Colored mesh overprinting of packaging containers (5)

The screen printing version of the screen requires the same requirements as the spot color printing, but when you need to handle the small screens, you must dry it on the screen. Whether you choose direct photosensitive coating or capillary stencil, your template must meet two requirements: one is to establish a sealing plate that can cover the mesh lines and level; the other is to minimize the deposition of ink. When the edge of the mesh is clear, it should be as thin as possible. If the template is too thick, the ink will be deposited in the mesh position during printing, and transfer to the substrate will result in dot gain and image smudging. For screen-printing makers, it is very difficult to make flat, smooth, thin-stenciled screens, because to make the screens relatively flat, multiple layers of photosensitive layers must be applied, but doing so is bound to Causes the coating to be thicker. The use of high-quality, high-curing direct emulsions is a requirement for half-tone printing, and is also a requirement for making capillary stencil films matching the number of screen lines. Emulsion coating technology plays a very important role in the quality of the finished product of the template. If it is practiced many times, it will make the technology more perfect. If you want to measure and control the stencil thickness and surface roughness, you should consider buying a thickness measurement device such as a triangometer and a Rz meter. These instruments can measure stencil surface characteristics or roughness. Exposure-related exposures are described in detail in the control and determination of the correct exposure and are not explained here. Correct exposure is very important for halftone printing because over or under exposure affects the size of the dot, which in turn affects the quality and color of the printed image. The effective exposure is mainly related to the light source. Therefore, in order to obtain a uniform light energy, it is best to use an optical integrator to compensate for the attenuation of the light energy and the light. Silk screen printing has been described in many articles on moire, but also stressed here. When you perform color separation printing, screen overlays are used. When different color screens are overlaid together, an unacceptable pattern will inevitably appear. This is the moire, but it can be to some extent. cut back. Moreover, the occurrence of moire is also related to color separation personnel. Each color has a different angle, yellow is at the smallest angle, and black is at the maximum angle. In short, make sure that the next color does not interfere with the previous process color. Although each color separation person knows that color separation uses a different angle, you must tell him what you need for the best angle for screen printing. A color separation person experienced in screen printing is undoubtedly a great help. Although you have the correct halftone screen angle, you should also pay attention to the angle of the screen because the image is exposed on the screen plate. Interference from the screen can also produce moiré patterns on the screen, so container printers sometimes encounter moiré patterns when the screen is tilted. Of course, this situation is rare, unless you use a scalable frame. However, since the angle of the original cannot be controlled on the container printer, the screen angle must be adjusted during the screen making process. So how do you determine the angle of the screen? Place the separation plate on the taut screen and rotate the separation plate until the angle of the moire is at the desired angle. The same method is applied to each color separation, and you can get satisfactory results. This shows that the angle you get this time is not suitable for other color separations. Another point is that if you overprint the screen on a sloping frame, it cannot be regenerated.