high frequency screen printer

custom t shirt printing, high-quality screen printing - threadbird

custom t shirt printing, high-quality screen printing - threadbird

We're a custom t-shirt printing & apparel company, specializing in high-quality discharge , waterbase and plastisol screen printing for brands, clothing companies, businesses and more. Take a look around our website to get a feel for what we're all about!

Our customers come in all shapes and sizes, but regardless of where you're headed or where you've been, Threadbird can help you achieve your goals through high-quality custom t-shirt printing, screen printing, embroidery and other custom merchandise.

frequency and angle for screen printing separations - coreldraw graphics suite x3 - coreldraw x3 and older - coreldraw community

frequency and angle for screen printing separations - coreldraw graphics suite x3 - coreldraw x3 and older - coreldraw community

Frequency depends on equipment, screen printing use a very low frequency 60 LPI or lower, and what is important with anglesis that theyhave to be30 degrees apart. Usually, cyan 15, magenta 75, yellow0, and black 45.Are you producing the separation? To produce truly low frequencies you may need an imagesetter, because laser printer cannot to produce them.

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the secret to full color screen printing screensilk

the secret to full color screen printing screensilk

Ever wonder how t-shirts are made that feature photographic quality design, in full color? This articles takes an in-depth look at the subject of cmyk printing and color separations, and their uses in screen printing. This casual approach to a difficult subject, should provide you everything you need to know to start producing full color artwork for fun and profit.

To tell you the truth, youre not alone. Many people ask me, but I have been hesitant to trust this information with you (or anyone else for that matter), because of the power you will have at your finger tips once I am through. This isnt a power to be taken lightly, with this power you can change the world.

I know, who are we kidding? I can see that certain something in your eyes. Something in there that says, Hey man, I want it quick and easy, and dont make me think. I feel ya homey, so heres my advice,

What? Really? You want to do it yourself? I mean, wouldnt you rather just hire a professional, pay outrageous fees, and not have to bore yourself with the advanced mathematics and the tedious process of memorizing formulas and stuff?

Ok, then.. But dont say I didnt warn you! And when your family starts sending me emails because your head exploded from this advance knowledge, you can bet I will sell their email address to some head implant specialist mailing list, and make a fortune off your tragedy. Are we still cool? Alright then.

Well, by Wikipedias definition, CMYK is a subtractive color model used in color printing. Yup, that pretty much sums it up. So, now that we have that out of the way, lets get onto something interesting.What? You still dont understand? Really? I thought that was pretty clear, but I will try to explain it for you.

This whole CMYK thing is based on the mixing of specific pigments in particular percentages to create a wide range of colors. Often times referred to as 4 color process. These specific pigments are as follows:

Now, the reason this is considered a subtractive color model is because the higher percentage of cyan, magenta, and yellow I smear onto a white sheet of paper, the less amount of light that will reflect through, ultimately creating a black (in this case, smudge) on our paper.

Why is black referred to as the letter K in CMYK? Well, back in the old days, when people really did use silk for screen printing, the word for black was actually Klack. What? Oh.. well, apparently that isnt true. Allegedly, the K actually stands for Key, as in the key plate used by a printer. I am being told that it was referred to as the key plate because it generally contained the artistic detail for a piece and was usually printed in klack.

Hold up a second. There is actually a bit more to discuss before we can dive in and start burning screens. Understanding what CMYK is and why it does what it does is really only the first step to moving forward into four color process printing.

Next we need to understand color separations. I had mentioned earlier how specific percentages of these particular pigments (cyan, magenta, yellow, and black), could be combined to create a wide range of colors.

Ok, so this is a pretty solid green. He looks to have his act together. Maybe a summer home on the cape, a nice car, a pretty little pink number he comes home to every night. But, if we look close we can see that this guy is just holding it together. In order to stay this solid green, he really needs to maintain some tight percentages. If one of these percentages starts to slip, he starts to lose his solid reputation.

We understood that all together, these color percentages make him what he is, but when they are separate, they are just percentages of color by themselves. Oh snap! Did you see what I said? When they are separate! So, pulling these colors away from each other into individual instances, is the act of creating color separations. And with color separations, we can make screens!

Oh, ya.. I almost forget about that part. Halftones. What? No, no its not a ska band. A halftone is the series of little dots you see when you look at a photograph in a newspaper. Halftones are dots of varying sizes and angles. The smaller the dot, the more white from the paper shows through effectively creating a lower percentage of color. The larger the dot (yup you guessed it), the higher the color percentage and the less white that shows through. When these dots are angled just right and printed over each other with their corresponding ink color, the effect is breath taking. These little dots, of varying sizes and colors, standing up against their diversities, united under a common good, to change our perception of the world around us. Or, in other words, they just appear to make some really pretty colors.

Ok, so where do we start. We have discussed how CMYK color separations require halftones in order to achieve the multitude of colors we want in a 4 color process image. There has been mention of dot sizes and angles that are necessary to achieve this effect properly. You may have noticed that I have yet to give you any solid numbers as far as dot sizes or angles for your halftones. I didnt do that so you would read through to the end of this article, if thats what your thinking. I did that because this is where I supply you with the facts and figures you need to make this work for you in the real world.

Lets start at the end and work back to the beginning. Mesh Count and thread diameter. Mesh count is the number of threads, per inch, that makes up your screen. Professional screen printers generally utilizes a screen with a mesh count of about 255 threads per inch and above, but typically mesh counts can range anywhere from 110 to 305. To make matters worst, there is also different thread diameters for screens. The higher your thread diameter in combination with your mesh count, the finer detail your artwork can contain, but also, the less ink that gets pushed through the screen. Inversely, the lower the thread diameter, the more ink that can be pushed through the screen, but the ability to maintain high details is lost.

So how do you go about choosing a mesh count? Well, for the sake of this article, and the process of 4 color printing on a screen, we want to go with the highest possible mesh count with the largest diameter of threads suitable for the material we are printing to. The higher our mesh count, the tighter our dots can be when we create our halftone.

First, we need to look at our mesh count, we can call that M. In order to figure out the optimal dot size of our halftone for our screen, we need to divide M by 3.5. Why 3.5 you ask? Mostly, because I like that number and have good result with it. But, because there are differing ideas of what number to use, most ranging anywhere from 3 5, feel free to experiment and let me know what works best for you.

Our LPI will dictate how many lines per inch we will have in our halftone. The higher our LPI, the more dots we can fit in per inch in our halftone, allowing us the ability to print a higher quality image.

Lets do a quick example of figuring out our LPI, and then we can move on to the awesomeness of angles. Lets say I have a screen with a mesh count of 220 threads per inch. If I divide that 220 mesh count by 3.5, I get a quotient of roughly 63. Looking at our reference table, that will produce a lower quality halftone than used in newspapers, but fairly average for screen printing. While it might be ok for this example, I would probably look at buying a higher mesh count screen to improve my halftone frequency.

Also, as a side note, if you dont have the screen yet, but now you want to achieve a halftone with an 85 lpi, you can always reverse the math to come up with the mesh count you should purchase. Always remember to round up if possible. Obvious? Maybe, but I thought Id mention it.

The final key to producing accurate 4 color halftone separations for output is the screen angle. Not the silk screen, the halftone screen! The series of dots that create the halftone are referred to as a screen. It is this screen, that once overlapped with the other color screens creates the final image. Each separation screen is printed at its own angle to prevent what is commonly referred to as the moir effect. Moir produce a sort of distorted, dizzying effect, and can ruin a good print job. To prevent moir patterns in your prints, a general rule of thumb is to offset each screen angle by 15 to 30 degrees.

Thanks for the wonderful insight into screen printing, Im just a little confused when you say offset screen angel by 15 to 30 degrees. What are the original values to offset it from? And how do you get to a suitable screen angle sample of c-75 m-15 y-105 k-45. I apologize if this sounds like a stupid question and if I am missing something simple.

Just read through this. Thanks for the info! Really aided my understanding. I think I understood everything, but the end part is a bit confusing to me still. If it is not the actual silk screen that is being offset, what screen is it? I know its the halftone screen you are talking about, but where would that be exactly? Asking because I cant see where the halftone angle printing would come in between printing your positive on the vinyl and then burning the positive image into the screen. ( Im new to this. Just trying to understand before I start off manually doing it )

Hi! This article was extremely helpful! I am teaching a class on color management and I was trying to convey a way to explain screen printing so that any student level could understand it! Perfect! Thank you, Lisa

This article has been super educational for me! Thanks so much for taking the time to write it. Theres one part Im still unclear about and thats how to actually create silk screens from halftone artwork in photoshop. I totally get how the color separation works to create an image but Im just not sure how to create multiple layers from this halftone pattern. HALP!

choosing the right image resolution for your print job

choosing the right image resolution for your print job

Have you ever had a print job done and was disappointed with the quality of the images?This could have been the result of low image resolution of the photos you provided. Using low resolution images is one of the most common errors designers make when creating designs for print. But first, let us clarify some of the terminology before we explain further.

Image Resolution is the fineness ordetail in a bitmap image and is measured in pixels per inch (ppi). The more pixels per inch, the greater the resolution. Generally, an image with a higher resolution produces a better quality printed image. A lower resolution image will be fuzzy, and less detailed (see illustrations below).

Printer resolution is measured in dots per inch (dpi) and refers to the smallest size dot a printing device can print. Generally, the more dots per inch, the finer the printed output youll get. However, image resolution (ppi) and screen frequency (lpi) generally affects the quality of the print project more than printer resolution (dpi) does. Most consumer grade laser and inkjet printers print at 300 dpi to 1,200 dpi. High-end inkjet, laser printers and imagesetters print at 1,200 to 2,400 dpi. Printer resolution is different from, but related to image resolution.

Screen frequency (also known asscreen rulingorline screen) is the number of printer dots orhalftone dots per inch used to print images. Screen frequency is measured in lines per inch (lpi.) The higher the resolution of the output device (printer), the higher (finer) screen frequency you can use. A typical 300dpi laser printer will producehalftones at about 50 lpi. Newspapers print about 85 lpi and most magazines print runs at 133 lpi to 150 lpi.

If you are printing at 150 lpi, you will need an image that is 300 ppi (150 lpi x 2 = 300 ppi). For printing at 200 lpi, you will need an image that is 400 ppi (200 lpi x 2 = 400 ppi). Normally, type should not be embedded inside non-vector graphics but when this is unavoidable, the image resolution should be set at or above 600 ppi.Line artshould be set at 1,200 ppi.

If you are going to scale your photos, keep in mind that they will lose quality as you enlarge them. Image resolution is inversely proportional to size. A 300 ppi image enlarged by 200% becomes 150 ppi. So the same formula can be expanded to:

So, if you are printing at 150 lpi and you are enlarging the image 200%, you will need a graphic that is 600 ppi ([150 lpi x 2]x2 = 600 ppi). If you enlarge the same image by 150%, you will need a graphic that is 450 ppi([150 lpi x 2]x 1.5= 450 ppi).

As a general rule, make sure that the photos you use are at least 300 ppi at 100% of the final size for general print services. Offset presses at higher screen frequencies require higher resolution bitmapped images.

For large format print marketing materialslike banners, posters, window graphics etc. that are meant to be viewed at more than an arms length away, we dont quite need the same image resolution.You should be able to get great results as long as the imagesare at least 150 ppi at 100% size. Typically, the further the viewing distance is, the lower the image resolution needs to be. A billboard is typically printed at 10 ppi to 30 ppi. Bear in mind though that image quality is not just measured by image resolution exposure, sharpness, noise, dynamic range, contrast, colour accuracy, etc. also play a part in creatinghigh qualityprinted materials.

If you try to use an image from a website (typically saved as 72 ppi) for printing, you will be vastly disappointed with the results. You will need to get the original image (before it was downsized and compressed for the web) and resize it to the right size with the necessary image resolution. Should you up-sample the image (increase the resolution of the image) in Photoshop?Sometimes, you just dont have a choice but to increase the resolution of an image to try and improve the print quality. Photoshops Bicubic interpolation works well for digital images with low noise. However, normal enlargement will usually cause a loss of detail or sharpness and introduce artifacts. To up-sample images with low resolution, weemploystate-of-the-art softwaretechnologies that uses fractal-based algorithms that optimizes clarity and detail of the enlarged image.

How do you get good quality images from your digital camera? Set your cameras image quality to the highest setting possible with the least amount of compression and use the largest image size. Save your photos as Raw files or digital negatives (e.g. Nikon uses NEF, Canon uses CRW) to retain the most image information. You can also save your images as TIFF, which is a lossless file format (as opposed to JPEG, which is a lossy format meaning that every time you save a JPEG file, the file is compressed by throwing away image information). To print a 8 x 10 photo at 300 dpi, you will need an image that is 2,400 x 3,000 pixels or a total area of 7,200,000 pixels (7.2 million pixels or megapixels). Most digital cameras and mobile phones can at shoot more than 7 megapixels these days.

Samco Printers is a full service commercial printer providing exceptional offset, digital and large format printing in Vancouver, British Columbia, Canada using the latest pre-press, printing and finishing technologies. We also have a fully equipped art department to handle your graphic and web design needs.

Need help? Let us help you get started or put the finishing touches on your printed materials. Our Art Director will be happy to spend some time with you. Give us a call at 604.683.6991 or send an email to [email protected]

screen printed passive components for flexible power electronics | scientific reports

screen printed passive components for flexible power electronics | scientific reports

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Additive and low-temperature printing processes enable the integration of diverse electronic devices, both power-supplying and power-consuming, on flexible substrates at low cost. Production of a complete electronic system from these devices, however, often requires power electronics to convert between the various operating voltages of the devices. Passive componentsinductors, capacitors and resistorsperform functions such as filtering, short-term energy storage and voltage measurement, which are vital in power electronics and many other applications. In this paper, we present screen-printed inductors, capacitors, resistors and an RLC circuit on flexible plastic substrates and report on the design process for minimization of inductor series resistance that enables their use in power electronics. Printed inductors and resistors are then incorporated into a step-up voltage regulator circuit. Organic light-emitting diodes and a flexible lithium ion battery are fabricated and the voltage regulator is used to power the diodes from the battery, demonstrating the potential of printed passive components to replace conventional surface-mount components in a DC-DC converter application.

Recent years have seen the development of a wide variety of flexible devices for applications in wearable and large-area electronics and the Internet of Things1,2. These include energy harvesting devices such as photovoltaics3, piezoelectrics4 and thermoelectrics5; energy storage devices such as batteries6,7; and power-consuming devices such as sensors8,9,10,11,12 and light sources13. While a great deal of progress has been made on the individual energy sources and loads, combining these components together into a complete electronic system typically also requires power electronics to overcome any mismatch between the source behavior and the loads requirements. For example, batteries produce a variable voltage dependent on their state of charge. If a load requires a constant voltage, or a higher voltage than the battery can produce, then power electronics are necessary. Power electronics use active components, transistors, to perform switching and control functions, as well as passive componentsinductors, capacitors and resistors. In a switching voltage regulator circuit, for example, inductors are employed to store energy during each switching cycle, capacitors are used to reduce voltage ripple and the voltage measurement required for feedback control is accomplished using a resistor divider.

Power electronics appropriate for the demands of wearable devices such as the pulse oximeter9, which requires a few volts and a few milliamps, typically operate at frequencies in the range of hundreds of kHz to a few MHz and require inductance and capacitance of several H and several F, respectively14. The conventional approach for manufacturing these circuits is to solder discrete components onto a rigid printed circuit board (PCB). While the active components of a power electronic circuit are often combined into a single silicon integrated circuit (IC), the passive components are usually external, either to allow customization of the circuit or because the required inductance and capacitance values are too large to be achieved in silicon.

Fabrication of electronic devices and circuits by additive printing processes offers a number of advantages in terms of simplicity and cost when compared to the conventional PCB-based manufacturing techniques. First, since many components of a circuit require the same materials, such as metal for contacts and interconnects, printing allows multiple components to be fabricated simultaneously, with relatively few processing steps and few sources of materials15. Replacing subtractive processes such as photolithography and etching with additive processes further reduces process complexity as well as materials waste16,17,18,19. In addition, the low temperatures used in printing are compatible with flexible and inexpensive plastic substrates, allowing large areas to be covered with electronics using high-speed roll-to-roll manufacturing processes16,20. For applications that cannot be fully realized using printed components, hybrid approaches have been developed in which surface-mount technology (SMT) components are attached at low temperature to flexible substrates alongside the printed components21,22,23. In such hybrid approaches, replacing as many SMT components as possible with their printed counterparts is still desirable to reap the benefits of the additive processes and improve the overall flexibility of the circuit. To achieve flexible power electronics, we propose a combination of SMT active components and screen-printed passive components, with particular emphasis on replacing bulky SMT inductors by planar spiral inductors. Of the various technologies for fabricating printed electronics, screen printing is especially well suited for passive components because of its large film thickness (which is necessary to minimize series resistance of metallic features) and its high printing speed, even when covering centimeter-scale areas with material24.

It is essential to minimize losses in passive components for power electronics, since the efficiency of the circuit directly affects the size of the energy source that is required to power a system. This is particularly challenging for printed inductors, which consist of long coils and are therefore susceptible to high series resistance. As a result, although there has been some effort toward minimizing resistance of printed coils25,26,27,28, there remains a lack of efficient printed passive components for power electronics. To date, many reported printed passive components on flexible substrates are designed to operate in resonant circuits for radio frequency identification (RFID) or energy harvesting purposes10,12,25,27,28,29,30,31. Others focus on materials or fabrication process development and demonstrate general-purpose components that are not optimized for a particular application26,32,33,34. Power electronic circuits such as voltage regulators, by contrast, tend to utilize larger components than the typical demonstrations of printed passives and do not require resonance, thus demanding different component designs.

Here, we present the design and optimization of screen-printed inductors in the H range to achieve minimal series resistance and high performance at frequencies relevant to power electronics. Screen-printed inductors, capacitors and resistors with various component values are fabricated on flexible plastic substrates. The suitability of these components for flexible electronics is first demonstrated in a simple RLC circuit. Printed inductors and resistors are then integrated with an IC to form a step-up voltage regulator. Finally, organic light-emitting diodes (OLEDs) and a flexible lithium-ion battery are fabricated and the voltage regulator is used to power the OLEDs from the battery.

To design printed inductors for power electronics, we first predicted the inductance and DC resistance of a range of inductor geometries based on the current sheet model presented in Mohan et al.35 and fabricated inductors of different geometries to confirm the accuracy of the model. A circular shape was selected for the inductors in this work because higher inductance can be achieved with lower resistance compared to polygon geometries36. The effect of the type of ink and the number of print cycles on resistance was determined. These results were then used along with the current sheet model to design 4.7H and 7.8H inductors optimized for minimum DC resistance.

The inductance and DC resistance of a spiral inductor can be described by a few parameters: the outer diameter do, turn width w and spacing s, number of turns n and the sheet resistance Rsheet of the conductor. Fig. 1a shows a photograph of a screen-printed circular inductor with n=12, indicating the geometric parameters that determine its inductance. Inductance was calculated for a range of inductor geometries according to the current sheet model of Mohan et al.35, in which

(a) Photograph of a screen-printed inductor, indicating geometric parameters. Diameter is 3cm. Inductance (b) and DC resistance (c) for a variety of inductor geometries. Lines and markers correspond to calculated and measured values, respectively. (d,e) DC resistance of inductors L1 and L2, respectively, screen-printed from Dupont 5028 and 5064H silver inks. (f,g) SEM micrographs of films screen-printed from Dupont 5028 and 5064H, respectively.

At high frequencies, the skin effect and parasitic capacitance change an inductors resistance and inductance from their DC values. It is desirable to operate the inductor at frequencies low enough that these effects are negligible and the device behaves as a constant inductance with a constant resistance in series. Thus, in this work we analyze the relationships between the geometric parameters, inductance and DC resistance and use the results to obtain a given inductance with minimum DC resistance.

Inductance and resistance were calculated for a range of geometric parameters achievable with screen printing and expected to give inductances in the H range. Outer diameters of 3 and 5cm, line widths of 500 and 1000m and various numbers of turns were compared. The calculations were performed assuming a sheet resistance of 47m/, corresponding to a single 7m thick layer of Dupont 5028 silver microflake conductor printed using a 400-mesh screen and setting w=s. Calculated inductance and resistance values are shown in Fig. 1b,c, respectively. The model predicts that inductance and resistance both increase as the outer diameter and number of turns are increased, or as the line width is decreased.

Inductors spanning a range of geometries and inductances were fabricated on polyethylene terephthalate (PET) substrates in order to assess the accuracy of the model predictions. Measured inductance and resistance values are shown in Fig. 1b,c. While the resistances show some deviation from the expected values, mainly due to variations in thickness and uniformity of the deposited ink, the inductance shows excellent agreement with the model.

These results can be used to design inductors having a desired inductance with minimum DC resistance. For example, suppose an inductance of 2H is desired. Figure 1b shows that this inductance can be achieved using 3cm outer diameter, 500m line width and 10 turns. The same inductance can also be produced using a 5cm outer diameter, with either 500m line width and 5 turns or 1000m line width and 7 turns (also shown in the figure). Comparing the resistance of these three possible geometries in Fig. 1c reveals that the 5cm inductor with 1000m line width has the lowest resistance of 34, about 40% lower than the other two. The generalized design process to achieve a given inductance with minimum resistance is summarized as follows: first, the largest allowable outer diameter is selected based on the spatial constraints imposed by the application. Then, the line width should be made as large as possible while still allowing the desired inductance to be reached, resulting in a high fill ratio (equation (3)).

Reducing the sheet resistance of the metal films, either by increasing the thickness or by using a material with higher conductivity, can further reduce the DC resistance without impacting the inductance. Two inductors, with geometric parameters given in Table 1, referred to as L1 and L2, were fabricated with varying number of coats to evaluate the change in resistance. As the number of coats of ink was increased, the resistance decreased proportionally as expected, as shown in Fig. 1d,e for inductors L1 and L2 respectively. Figure 1d,e show that up to 6-fold reduction in resistance can be achieved, through the application of 6 coats, while the greatest reduction in resistance (5065%) occurs between 1 and 2 coats. A screen with a relatively small mesh size (400 threads per inch) was used to print these inductors because each coat of ink is relatively thin, allowing us to investigate the effect of conductor thickness on resistance. Similar thickness (and resistance) could be achieved faster by printing a smaller number of coats with a larger mesh size, as long as the patterned features remain larger than the minimum resolution of the mesh. This approach could be used to achieve the same DC resistance as the 6-coat inductors discussed here, but with higher production speed.

Figure 1d,e also show that a twofold reduction in resistance is achieved by using a higher-conductivity silver flake ink, Dupont 5064H. As seen in the SEM micrographs of films printed from the two inks, Fig. 1f,g, the lower conductivity of the 5028 ink arises from its smaller particle size and the presence of many voids between the particles in the printed film. The 5064H, on the other hand, has larger and more closely packed flakes, giving behavior closer to that of bulk silver. While this ink produced thinner films than the 5028 ink, 4m for a single coat and 22m for 6 coats, the enhancement in conductivity was substantial enough that the resistance was reduced overall.

Finally, while the inductance (equation (1)) depends on the period of the turns (w+s), the resistance (equation (5)) depends only on the line width w. Therefore, by increasing w relative to s, the resistance can be reduced even further. Two additional inductors, L3 and L4, were designed with w=2s and large outer diameter, as shown in Table 1. These inductors were fabricated using 6 coats of Dupont 5064H, shown previously to give the highest performance. L3 had inductance of 4.720 0.002H with resistance of 4.9 0.1, while L4 had 7.839 0.005H and 6.9 0.1, in good agreement with the model predictions. This represents an improvement in the L/R ratio of more than an order of magnitude relative to the values in Fig. 1, due to the enhancements in thickness, conductivity and w/s.

Although a low DC resistance is promising, assessing the suitability of the inductors for power electronics operating in the kHz-MHz range requires characterization at AC frequencies. Figure 2a shows the dependence of resistance and reactance of L3 and L4 on frequency. For frequencies below 10MHz, the resistance stays roughly constant at its DC value and the reactance increases linearly with frequency, implying a constant inductance as expected. The self-resonant frequency, defined as the frequency at which the impedance transitions from inductive to capacitive, occurs at 35.6 0.3MHz for L3 and 24.3 0.6MHz for L4. The dependence of the quality factor Q, equal to L/R, on frequency is shown in Fig. 2b. L3 and L4 reach their maximum quality factors of 35 1 and 33 1 at frequencies of 11 and 16MHz respectively. The inductance of several H and relatively high Q in the MHz frequencies make these inductors adequate replacements for conventional surface-mount inductors in low-power DC-DC converters.

To minimize the required footprint for a given capacitance, it is desirable to use a capacitor technology with a large specific capacitance, equal to the dielectric permittivity divided by the thickness of the dielectric. In this work, we chose a barium titanate composite for the dielectric, because it presents higher than other solution processed organic dielectrics. The dielectric layer was screen-printed between two layers of the silver conductor to form a metal-dielectric-metal structure. Capacitors with various dimensions on the centimeter scale, as shown in Fig. 3a, were fabricated using either two or three coats of dielectric ink, to maintain good yield. Figure 3b shows cross-sectional SEM micrographs of a representative capacitor fabricated with two coats of dielectric, for a total dielectric thickness of 21m. The top and bottom electrodes are one and six coats of 5064H, respectively. The micron-scale barium titanate particles are visible in the SEM image as brighter areas surrounded by the darker organic binder. The dielectric ink wets the bottom electrode well forming a clear interface with the printed metal film, as shown in the higher-magnification inset figure.

(a) Photographs of the capacitors with five different areas. (b) Cross-sectional SEM micrographs of a capacitor with two coats of dielectric, showing the barium titanate dielectric and silver electrodes. (c) Capacitance of capacitors with 2 and 3 coats of barium titanate dielectric and varying area, measured at 1MHz. (d) Capacitance, ESR and dissipation factor of a 2.25cm2 capacitor with 2 coats of dielectric, vs. frequency.

The capacitance scales proportionally with area as expected, as shown in Fig. 3c, with a specific capacitance of 0.53nF/cm2 for two coats of dielectric and 0.33nF/cm2 for three coats. These values correspond to a permittivity of 13. Capacitance and dissipation factor (DF) were also measured at varying frequency, as shown in Fig. 3d for a 2.25cm2 capacitor with two coats of dielectric. We found that capacitance is relatively flat over the frequency range of interest, increasing by 20% from 1 to 10MHz, while the DF increases from 0.013 to 0.023 over that same range. As the dissipation factor is a ratio of energy lost to energy stored per AC cycle, a DF of 0.02 signifies that 2% of the power handled by the capacitor is dissipated. This loss is also often expressed as a frequency-dependent equivalent series resistance (ESR), equal to DF/C, in series with the capacitor. As shown in Fig. 3d, the ESR is below 1.5 for frequencies greater than 1MHz and below 0.5 for frequencies greater than 4MHz. While the F-scale capacitances needed for DC-DC converters would require prohibitively large areas using this capacitor technology, the 100pF - nF capacitance range and low loss of these capacitors makes them suitable for other applications, such as filters and resonant circuits. A number of approaches could be used to increase the capacitance. A higher dielectric constant would increase the specific capacitance37; this can be achieved by increasing the concentration of barium titanate particles in the ink, for example. A smaller dielectric thickness could be used, although this would require a bottom electrode with lower roughness than the screen printed silver flakes. Thinner, lower roughness layers for capacitors can be deposited by inkjet printing31 or gravure printing10, which could be integrated with the screen printing process. Finally, multiple alternating layers of metal and dielectric could be printed in a stack and connected in parallel, increasing the capacitance per unit area34.

Voltage dividers, consisting of a pair of resistors, are typically used to perform the voltage measurement necessary for feedback control of a voltage regulator. For this type of application, printed resistors should present resistances in the range of k-M and low variation from device to device. Here, a single coat of screen-printed carbon ink was found to have a sheet resistance of 900/. This information was used to design two straight-line resistors (R1 and R2) and one serpentine resistor (R3) with nominal resistances of 10k, 100k and 1.5M, respectively. Resistances in between the nominal values were achieved by printing two or three coats of ink, as shown in Fig. 4 alongside photographs of the three resistors. 812 samples of each type were fabricated; in all cases, the standard deviation of the resistances was 10% or less. Samples with two or three coats tended to have slightly less variation in resistance than those with one coat. The small variation in measured resistance and close agreement with the nominal values suggests that other resistances in this range can be obtained straightforwardly by modifying the resistor geometry.

An RLC circuit, a classic textbook example of the combination of resistor, inductor and capacitor, was fabricated to demonstrate and verify the behavior of the passive components integrated into a truly printed circuit. In this circuit, an 8H inductor and a 0.8nF capacitor were connected in series and a 25k resistor was placed in parallel with them. A photograph of the flexible circuit is shown in Fig. 5a. This particular series-parallel combination was selected because its behavior is dominated by each of the three components at different frequencies, allowing the performance of each one to be highlighted and assessed. The expected frequency response of the circuit was calculated, taking into account the 7 series resistance of the inductor and the 1.3 ESR of the capacitor. The circuit diagram is shown in Fig. 5b and the calculated impedance magnitude and phase are shown in Fig. 5c and d along with measured values. At low frequency, the high impedance of the capacitor means that the behavior of the circuit is dominated by the 25k resistor. As the frequency increases, the impedance of the LC path decreases; the overall circuit behavior is capacitive until the resonant frequency of 2.0MHz. Above the resonant frequency, the inductor impedance dominates. Figure 5 clearly shows the excellent agreement between the calculated and measured values over the entire frequency range. This signifies that the model used here, where the inductors and capacitors are ideal components with series resistances, is accurate for predicting circuit behavior at these frequencies.

(a) Photograph of screen-printed RLC circuit using a series combination of 8H inductor and 0.8nF capacitor, in parallel with a 25k resistor. (b) Model of the circuit including inductor and capacitor series resistances. (c,d) Impedance magnitude (c) and phase (d) of the circuit.

Finally, the printed inductors and resistors were implemented in a step-up voltage regulator. The IC used in this demonstration was the Microchip MCP1640B14, a PWM-based synchronous boost regulator operating at 500kHz. The circuit diagram is shown in Fig. 6a. A 4.7H inductor and two capacitors (4.7F and 10F) are used as the energy storage elements and a pair of resistors is used to measure the output voltage for the feedback control. The resistor values were chosen to regulate the output voltage to 5V. The circuit was fabricated on a PCB and its performance was measured over a range of load resistances and input voltages between 3 and 4V, simulating the voltages of a lithium ion battery at various states of charge. The efficiency with printed inductors and resistors was compared to that with SMT inductor and resistors. SMT capacitors were used in all cases, because the capacitances required for this application were too large to accomplish using the printed capacitors.

(a) Diagram of voltage regulator circuit. (bd) Waveforms of (b) Vout, (c) Vsw and (d) current into the inductor, with 4.0V input voltage and 1k load resistance, measured using printed inductor. Surface-mount resistors and capacitors were used for this measurement. (e) Efficiency of a voltage regulator circuit using all surface-mount components vs. one with printed inductor and resistors, for various load resistances and input voltages. (f) Ratio of efficiencies of the surface-mount and printed circuits shown in (e).

Waveforms measured using a printed inductor are shown in Fig. 6bd, for a 4.0V input voltage and 1000 load resistance. Figure 6c shows the voltage at the Vsw terminal of the IC; inductor voltage is Vin-Vsw. Figure 6d shows current into the inductor. Efficiency of the circuits with SMT and printed components is shown as a function of input voltage and load resistance in Fig. 6e, Fig. 6f shows the ratio of efficiency with printed components to that with SMT components. The measured efficiencies with the SMT components are similar to the expected values given in the manufacturers data sheet14. At high input currents (low load resistance and low input voltage), the efficiency is substantially lower with the printed inductor than the SMT inductor due to the higher series resistance. However, with higher input voltage and higher output current the resistive losses become less significant and the performance with the printed inductor begins to approach that of the SMT inductor. For load resistances >500 with Vin=4.0V, or >750 with Vin=3.5V, the efficiency with the printed inductor is >85% of the SMT inductor.

Comparing the current waveform in Fig. 6d with the measured power loss shows that resistive losses in the inductor are primarily responsible for the difference in efficiency between the printed and SMT circuits, as expected. The measured input and output power for 4.0V input voltage and 1000 load resistance were 30.4mW and 25.8mW for the circuit with SMT components and 33.1mW and 25.2mW for the circuit with printed components, respectively. The loss in the printed circuit is therefore 7.9mW, which is 3.4mW higher than the circuit with SMT components. The RMS inductor current calculated from the waveform in Fig. 6d is 25.6mA, giving an expected power loss of 3.2mW due to its series resistance of 4.9. This is 96% of the measured 3.4mW difference in DC power. Additionally, circuits were fabricated with a printed inductor and printed resistors as well as a printed inductor and SMT resistors and no significant difference in efficiency was observed between them.

A voltage regulator was then fabricated on a flex-PCB (performance of this circuit with printed vs. SMT components is given in Supplementary Fig. S1) and connected between a flexible lithium-ion battery as the source and an array of OLEDs as the load. The OLEDs were fabricated according to Lochner et al.9 and each OLED pixel drew 0.6mA at 5V. The battery employed lithium cobalt oxide and graphite respectively as the cathode and anode and was fabricated by blade coating, the most common battery printing method.7 The capacity of the battery was 16mAh and its voltage was 4.0V at the time of testing. Figure 7 shows a photograph of the circuit on a flex-PCB, powering three OLED pixels connected in parallel. This demonstration shows the potential of the printed power components to be integrated with other flexible and organic devices to form more complex electronic systems.

We have demonstrated screen-printed inductors, capacitors and resistors with a range of values on flexible PET substrates, with the goal of replacing surface-mount components in power electronics. We have shown that the resistance of the inductors, which is of great concern for power electronics, can be reduced by more than an order of magnitude by designing the spiral with large diameter, fill ratio and line width-space width ratio and by using a thick layer of low resistivity ink. The components were integrated into a fully printed and flexible RLC circuit and show predictable electrical behavior in the kHz-MHz frequency range that is most of interest for power electronics.

A typical use case for printed power electronics would be in a wearable or product-integrated flexible electronic system powered by a flexible rechargeable battery, such as lithium ion, which produces a variable voltage depending on its state of charge. If the loads, which would include printed and organic electronic devices, require a constant voltage or one that is higher than the battery output, a voltage regulator is needed. For this reason, the printed inductor and resistors were integrated into a step-up voltage regulator alongside a conventional silicon IC, which was used to power OLEDs at a constant voltage of 5V from a variable-voltage battery source. Efficiency of the circuit surpassed 85% of that of a control circuit using surface-mount inductor and resistors over a range of load currents and input voltages. Despite the material and geometry optimization, resistive losses in the inductor remained the limiting factor of the circuit performance at high current levels (input current greater than about 10mA). At lower currents, however, the losses in the inductor were reduced and the overall performance became limited by the IC efficiency. Since many printed and organic devices require relatively low currents, such as the small OLEDs used in our demonstration, the printed power inductor can be deemed appropriate for this type of application. Higher overall converter efficiency may be achieved by utilizing an IC designed to have the highest efficiency at lower current levels.

In this work, voltage regulators were built upon conventional PCB, flex-PCB and soldering techniques for the surface-mount components and the printed components were fabricated on separate substrates. However, the low temperatures and high-viscosity inks used to produce screen-printed films should allow the passive components, as well as interconnects between devices and contact pads for surface-mount components, to be printed on arbitrary substrates. This combined with the use of existing low-temperature conductive adhesives for the surface-mount components would allow the entire circuit to be built, without subtractive processes such as PCB etching, on an inexpensive substrate such as PET. The screen-printed passive components developed in this work therefore help to pave the way for flexible electronic systems integrating energy sources and loads with high-performing power electronics, using inexpensive substrates, primarily additive processes and a minimum number of surface-mount components.

All layers of the passive components were screen printed onto flexible PET substrates, 76m in thickness, using an Asys ASP01M screen printer and stainless steel screens supplied by Dynamesh Inc. Mesh size was 400 threads per inch for the metal layers and 250 threads per inch for the dielectric and resistor layers. Screen printing was performed using a squeegee force of 55N, print speed of 60mm/s, snap-off distance of 1.5mm and Serilor squeegees with hardness of 65durometer (for metal and resistor layers) or 75durometer (for dielectric layer).

Conductive layersinductors and the contacts to the capacitors and resistorswere printed from either Dupont 5082 or Dupont 5064H silver micro-flake ink. Resistors were printed from Dupont 7082 carbon conductor. For the capacitor dielectric, Conductive Compounds BT-101 barium titanate dielectric was used. Each coat of dielectric was produced using a double pass (wet-wet) print cycle to improve uniformity of the film. For each component, the effect of multiple print cycles on component performance and variability was examined. Samples made with multiple coats of the same material were allowed to dry for 2minutes at 70C between coats. After the final coat of each material, the samples were baked at 140C for 10minutes to ensure complete drying. The screen printers automatic alignment feature was used to align subsequent layers. Contacts to the center of the inductor were made by cutting a via into the center pad and stencil printing a trace on the backside of the substrate with Dupont 5064H ink. Interconnects between printed devices were also stencil printed from Dupont 5064H. For the demonstration of printed components and SMT components together on a flex-PCB shown in Fig. 7, printed components were attached using Circuit Works CW2400 conductive epoxy and SMT components were attached using conventional soldering.

Lithium cobalt oxide (LCO) and graphite based electrodes served as the cathode and anode for the battery, respectively. Slurry for the cathode was a mixture of 80wt% LCO (MTI Corp.), 7.5wt% graphite (KS6, Timcal), 2.5wt% carbon black (Super P, Timcal) and 10wt% polyvinylidene fluoride (PVDF, Kureha Corp.) and for the anode was a mixture of 84wt% graphite, 4wt% carbon black and 13wt% PVDF. N-methyl-2-pyrrolidone (NMP, Sigma Aldrich) was used to dissolve the PVDF binder and disperse the slurry. The slurries were homogenized by stirring overnight with a vortex mixer. A 0.0005 thick stainless steel foil and 10m nickel foil served as the current collectors for the cathode and anode, respectively. The inks were printed on the current collector with a doctor blade at a print speed of 20mm/s. The electrodes were heated in an oven at 80 C for 2hr to remove the solvent. The height of the electrode after drying was ~60m resulting in theoretical capacity of 1.65mAh/cm2 based on the weight of the active material. The electrodes were cut to a dimension of 1.31.3cm2 and heated overnight in a vacuum oven at 140 C before sealing them with aluminum-laminated pouch in nitrogen filled glove box. Polypropylene based membrane separated with anode and cathode and a solution of 1M LiPF6 in EC/DEC (1:1) served as the electrolyte for the battery.

Green OLEDs were fabricated from a blend of poly(9,9-dioctylfluorene-co-n-(4-butylphenyl)-diphenylamine) (TFB) and poly((9,9-dioctylfluorene-2,7-diyl)-alt-(2,1,3-benzothiadiazole-4, 8-diyl)) (F8BT), according to the procedure outlined in Lochner et al.9.

Film thickness was measured with a Dektak stylus profilometer. The films were cut to prepare cross-sectioned samples for a study by scanning electron microscope (SEM). A FEI Quanta 3D field emission gun (FEG) SEM was used to characterize the structure of the printed films and confirm thickness measurements. SEM study was carried out under 20keV accelerating voltage and typical working distance of 10mm.

DC resistances, voltages and currents were measured with a digital multimeter. AC impedance of inductors, capacitors and circuits was measured with an Agilent E4980 LCR meter for frequencies below 1MHz and an Agilent E5061A network analyzer for frequencies above 500kHz. Voltage regulator waveforms were measured with a Tektronix TDS 5034 oscilloscope.

Rabaey, J. M. The Human Intranet: Where Swarms and Humans Meet. Paper presented at 2015 Design, Automation & Test in Europe Conference & Exhibition, Grenoble, France. San Jose, CA, USA: EDA Consortium. 637-640 (2015, March 9-13).

Subramanian, V. et al. Printed electronics for low-cost electronic systems: Technology status and application development. Paper presented at ESSDERC 200838th European Solid-State Device Research Conference, Edinburgh, UK. IEEE. 1724. doi:10.1109/ESSDERC.2008.4681691 (2008, September 15-19).

Ben-Salah Akin, M., Rissing, L. & Heumann, W. Enabling eutectic soldering of 3D opto-electronics onto low Tg flexible polymers. Paper presented at 2014 IEEE 64th Electronic Components and Technology Conference (ECTC), Orlando, FL, USA. IEEE. 15951600. doi:10.1109/ECTC.2014.6897507 (2014, May 27-30).

McKerricher, G., Perez, J. G. & Shamim, A. Fully inkjet printed RF Inductors and capacitors using polymer dielectric and silver conductive ink with through vias. IEEE Trans. Electron Devices 62, 10021009 (2015).

Stojanovic, G. & Zivanov, L. Comparison of optimal design of different spiral inductors. Paper presented at 2004 24th International Conference on Microelectronics, Serbia and Montenegro. IEEE. 2, 613616 (2004, May 16-19).

Reboun, J., Blecha, T., Syrovy, T., Hamacek, A. & Shlykevich, A. Printed passive components for RFID labels. Paper presented at 5th Electronics System-integration Technology Conference (ESTC), Helsinki, Finland. IEEE. 15 (2014, September 16-18).

This work was supported in part by the National Science Foundation under Cooperative Agreement No. ECCS-1202189. A.E.O. and C.M.L. were supported by the NSF Graduate Research Fellowship Program under Grant No. 1106400. We thank Cambridge Display Technology Limited (CDT) for supplying OLED materials and Dr. Anita Flynn, Dr. Balthazar Lechne, Joseph Corea and Yasser Khan for helpful technical discussions.

A.E.O. designed and fabricated the passive components and circuits and performed electrical characterization. I.D. performed the SEM imaging. A.M.G. fabricated the batteries. C.M.L. fabricated the OLEDs. A.E.O. wrote the manuscript, while A.C.A., I.D. and A.M.G. contributed to the experimental design and writing. All authors discussed the results and commented on the manuscript.

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the articles Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

electric, magnetic and high frequency properties of screen printed ferrite-ferroelectric composite thick films on alumina substrate
 | emerald insight

electric, magnetic and high frequency properties of screen printed ferrite-ferroelectric composite thick films on alumina substrate | emerald insight

The purpose of this article is to study the effect of ferrite content on electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) thick films on alumina.

Thick films of ferriteferroelectric composite on alumina substrate have been delineated using screen printing technique. The structural analysis was carried out using X-ray diffraction method and scanning electron microscopy. The DC electrical resistivity was measured using the two-probe method. The magnetic measurement was carried out using a vibrating sample magnetometer. Microwave absorption was studied in the 8-18 GHz frequency range by using the vector network analyzer (N5230A). The permittivity in the 8-18 GHz frequency range was measured by using voltage standing wave ratio slotted section method.

The formation of two individual ferriteferroelectric phases in composite thick films was confirmed by the X-ray diffraction patterns. The scanning electron microscope morphologies show the growth of cobalt-substituted nickel cadmium ferrite grains which are well dispersed in lead zirconium titanate matrix. The DC electrical resistivity increases with increase in ferrite content and decreases with increase in temperature. The present ferrite shows ferromagnetic nature and it increases saturation magnetization and coercivity of the composite thick films. Tuning properties are observed in the Ku-band and broadband X-band microwave absorption is observed in the composite thick films. The imaginary part of permittivity increases with an increase in ferrite content, which increases microwave absorption. The real part of microwave permittivity varied from 17 to around 22 with an increase in ferrite content and it decreases with frequency. The microwave conductivity, which increases with an increase in ferrite content, reveals the loss of polaron conduction, which supports the dielectric loss in the microwave region.

Electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) composite thick films on alumina substrate is reported for the first time.

One of the authors, Dr Vijaya Puri, gratefully acknowledges UGC for the award of research scientist C. N.D. Patil thanks UGC-BSR for the meritorious fellowship. N.B. Velhal acknowledges DAE-BRNS for providing JRF. R.S. Pawar acknowledges DST for the award of Women Scientist A.

Patil, N., Velhal, N.B., Pawar, R. and Puri, V. (2015), "Electric, magnetic and high frequency properties of screen printed ferrite-ferroelectric composite thick films on alumina substrate", Microelectronics International, Vol. 32 No. 1, pp. 25-31. https://doi.org/10.1108/MI-12-2013-0080

film output tutorial

film output tutorial

Colors from a color separation are imaged as positives onto transparent film for screen printing.Film positives are output onto sheets or rolls of film using many types of film output devices. Inkjet printers with the correct film work well for output, are inexpensive, and readily available.

Black and White Film positives for making a screen printing stencil are printed with solid black shapes on a clear background. Gray tones that are not 100% white or black need to be converted to a shape or pattern. The most common approach is to use aHalftone dot.

Halftone Dots Halftones are named by the number of dots used per inch, this is the halftone frequency.While the size of the white and black areas in a Halftone pattern changes, the number of dots per inch remain the same. The halftone dots create a pattern of light and dark . Overlapping halftone patterns can be rotated to reduce interference, or moire. The degree of rotation is called the Screen Angle.

Frequency The size of the dot used is determined by the screen printing mesh. For simulated process and process printing it is best to keep the dots as small as possible, so using a fine mesh is best. Mesh counts between 195 and 355 are common, using halftone dot frequencies between 40 and 65 lpi.

Increasing the mesh count can help to reduce moire. Underbase use a 195 mesh with a 45 to 50 lpi halftone. Colors Use 230 to 305 mesh with 50 to 55 lpi. Black and Highlight Use 305 to 355 Mesh with 50 to 65 lpi.

Angle and the Moire Pattern Moire appears as light and dark areas in an image when two regular patterns are overprinted. When halftone screens are used, their alignment can be changed by a few degrees to reduce this effect. The regular patterns that can cause Moire in screen printing include various halftone dots, the mesh itself, and the garment being printed on. A good set of angles are: 22.5 52.5 82.5

On light colored garments the white, yellow and blacks can all be at the same angle:22.5 The reds and oranges :52.5 And the blues, greens and purples at the third angle:82.5 On a dark colored garment put the under print at 22.5 and the black at 52.5.

Edge definition and Banding When considering the quality of your film output it is important to look closely at the edges of the halftone dots, text and graphics. Output resolutions below 600ppi will leave halftone dots poorly defined. Output resolution is determined by the Printers resolution as well as the halftone conversion method.

The ability of a halftone to represent a grayscale is also determined by its output resolution. Lower output resolutions from a printer or a Rip (Raster Image Processor), can limit a halftones range of values, and the result is banding. Banding is an apparent step between different values in a grayscale. To eliminate banding, either increase the output resolution, or decrease the halftone screen count.

Check for banding in the original image first. Banding can be caused by several factors before your image is output. If an image is smooth but the output is banded then it is caused by the output resolution and halftone line count. The number of gray levels that can be created by a halftone line screen at a specific output resolution can be calculated using a formula. .

According to the formula, at an output resolution of 720ppi, we will need to use a 45 line screen to get the 256 levels of gray we see on screen. In practice a 50 line screen works well with an output resolution of 720 ppi. If you do have problems with banding in your output, you can either reduce the halftone line count, or increase the output resolution, until the banding is eliminated.

Printing from Adobe Photoshop In Adobe Photoshop the output settings can be found in the print preview dialog. Under the file menu choose Print, or Print with preview In earlier versions: ( PS7 to CS2 ) File/Print with Preview:

Color Management Print using the Print with Preview option. Select More Options to open the options dialog. Set the output drop down to Color Management. Set the print space to Document. Set the Color Handling Option to Separations.

Printing from Adobe Photoshop to a third party Rip A Rip is a software program does the job of controlling a printers output, providing control over a range of functions including color conversion, ink deposit and dot patterns. A Rip can convert grayscale images to a halftone dot screen as part of its function to control a printers output. Some Rips do not produce dots large enough to be screen printed and are designed for color reproduction, while other Rips are developed to produce only film and can not be used for color printing. Consult the Rips instruction manual to ensure it is capable of creating the needed halftones and the proper setup procedure. A Rip needs to be properly configured to create a quality film output. A good Rip will allow you to set your Screen angles and frequencies within Adobe Photoshop.

Film Output Settings Dot Size, Shape and Angle Choose the Output Settings drop down in the print preview menu, click Screen to set the halftone dots. In the Screen Menu, uncheck Use Default Screen and set the Frequency and Screen Angle for each channel. Each spot color and CMYK channel can be selected from the drop down menu. Select Ellipse for the dot shape, and select Use Accurate Screens and Use Same Shape for All Inks.

Bitmap Halftones High resolution 1 bit images can be printed straight to film with good results. Separation channels can be converted to halftones using the built in Bitmap function. Converting a document to grayscale or multichannel mode enables the bitmap mode option. Only the single, or top channel will be used in the conversion.

Film Output using SimRip SimRip2 is designed to take the hassle out of bitmap conversion in Adobe Photoshop. File processed through SimRip are ready to be sent to a film output device like an inkjet printer. SimRip2 automates the process of converting multiple channels to halftones.

Dot Gain All printing devices produce some dot gain which needs to be compensated for, and a Rip will allow for this gain by applying a linearization curve. A linearization curve can be made by taking a set of readings using a Transmission densitometer, measuring each 10% step along the value range from a printed halftone step wedge. These measurements are used to create a curve that compensates for the changes in dot size that result from printing.

Every printer is different in the amount of gain it produces on a particular film, so ideally we would want to create a Linearization curve for each printer and film combination. For screen printing we just need to get in the ballpark, however, so a generic curve will often work fine. To compensate for dot gain, apply a linearization curve to an image or separation channel prior to conversion to bitmap.

Files can be converted back to grayscale and multichannel as needed, being careful not to resize or modify the image. If the image size needs to be changed, it is best to go back and modify the original and reconvert the image to Halftones. To convert the bitmap image back to a channel choose: Image/Mode/Grayscale Enter 1 in the Size ratio box and click OK,

Printing bitmap images onto film using a standard Printer Driver. Files converted in this way can be printed straight to film using a standard printer driver, avoiding the need for processing with a Rip. Use a quality, transparent polyester film coated for inkjet printing, a printer with resolutions of 1440 or higher, and a quality ink such as Epson Black.

The quality of results from this technique depend entirely on the quality of the ink and film used. Inkjet printers using pigment based inks will require a specially coated waterproof film, while dye based inks generally print on coated, non-waterproof films as well. Most films are coated on a single side, and can be printed on the coated side only.

Printing from Adobe Photoshop Using the same process as above; Select your printer in the Print with Preview menu, set the color management settings to separations, and the output settings to print labels and registrations marks if needed. Screens should be left to the default setting. Click Print.

Increasing print density In most cases using a resolution of 1440 will provide a high density print when applied to a quality film. In some cases the ink density in the film output can be increased by merely increasing the output resolution. In other cases increasing the density may be possible within the driver itself. Increasing print density can greatly improve the quality of your film output.

In the dialog below the driver has additional output controls which allow for increased ink density. It is important to remember that any increases to the ink density will increase overall dot gain from the output device. The minimum ink deposit required for an opaque print is best.

Related Equipments