The two most popular factors affecting the quality

2022-07-23
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Two factors affecting the quality of PS plates

although CTP has been used for a long time and has begun to be popularized in China, some printing enterprises still use PS plates. PS plate is still the largest printing plate used in China at this stage. Let me introduce two important conditions that determine the quality of PS plate: original plate quality and plate quality

in offset printing, the inconvenience of making this kind of plastic bag and using the plate for many times is the guarantee of printing quality. Only by ensuring the plate making quality of PS plate can the quality of printed matter be ensured. So, what are the key points for a good quality printing plate? Let's explain in detail from the two aspects of original quality and plate quality

1. Original quality

original refers to the film or sulfuric acid paper output before printing. Its quality directly affects the plate making effect of PS plate. There are two important indicators for the quality of the original version:

(1) point density

when printing the positive image, the points must have sufficient density. The density of a single point is more than 3.0, and the field density reaches 3.15 million plastic bottles, creating a "floating paradise" Above 5, the transmission density of the blank area of the film shall be lower than 0.05

(2) smooth point

the center density of the point is consistent with the edge density, so as to expand the tolerance of exposure time. The original version shall be clean and free of dirt. It is better to use a complete film without knife edge and collage tape to ensure that the film is closely combined with the PS version and avoid the phenomenon of dot fuzziness caused by light scattering

2. The plate material quality

has little impact on the samples such as thin plates after breaking

(1) the plate base

should be clean, consistent in thickness, and evenly distributed with moderate thickness and depth. The photosensitive solution shall be evenly coated without bubbles and scars. Generally, it is required that the average depth (RZ) of sand mesh is 5 ~ 7.5 m, and the average roughness (RA) is about 0.6 M

(2) the photosensitive adhesive layer

the photosensitive coating is uniform and moderate in thickness, which can not only completely cover the sand convex peaks, but also be too thick, which will affect the resolution of the printing plate. Generally, the thickness of PS plate coating layer is about 1.8 g/m2

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