PS version of the printing process

Exposure→Development→Washing→Retouch→Sticking→Drying→Print on the machine. (Positive Photographic Photopolymer film is decomposed by light)

First, the printing process on the impact of the PS version of the Indian version of the positive version of the PS plate in the Stencil iodine lamp (3000W) under the irradiation of ultraviolet light, the exposure time is generally about 100 seconds, PS version of the photosensitive film by the light irradiation part Quickly decompose, then add 70g water to 1000ml with a weak alkaline solution containing sodium silicate, sodium hydroxide component of the developer powder, can also be used 1:8 ratio formulation of the developer kit. Since the photosensitive film of the non-graphic part of the PS plate is decomposed by light, a solution that encounters alkalinity during development is dissolved in an alkaline developer to form a hydrophilic blank, and the unsensitized image portion remains after development. Stayed on the plate base, become the printing part of the printing plate, the exposure and development here are the factors that affect the printing plate's printing rate.

The PS version has a spectral sensitivity range in the blue and near-ultraviolet regions (310 to 450 nm). Exposure to iodine and metal halide light sources is most suitable. The standard exposure time can be used as a printed signal bar produced by the China Institute of Printing Research. Reference to determine the control exposure time is determined by continuously adjusting the transmission ash ladder, screen ladder, or print control bar.

The above printing time is based on the distance between the light source and the layout distance of 1m, and the exposure time is adjusted according to the change of the exposure distance of the light source. In addition, the iodine and xenon lamp has new and old points. If the iodine lamp is used for a long time, the luminous intensity is correspondingly weaker. To increase the exposure time accordingly, at the same time, the level of voltage at work will also have an impact on the luminous intensity, and it is necessary to adjust the situation in time.

Because the type of light source used in the exposure PS plate is different, it is difficult to determine a uniform exposure time. However, for a PS plate produced by the same model and the same manufacturer, there should be an exposure amount to determine the exposure time based on: 3% of small dots Not lost, 50% of the outlets do not scale, and 98% of outlets do not paste. The ideal exposure time enables the ideal degree of reduction on the PS plate to be achieved on the soft sheet, sulfate text, lines, and image density levels and dots.

In short, controlling the exposure of the PS plate during printing is the key, and the small dots of the overexposed plate are lost, which will affect the reduction of the tone. If the exposure time is not enough, it is difficult to develop, and the blank part is easy to print. Dirty, latent image. In order to overcome the development difficulties caused by underexposure, in general, two approaches are taken: 1. Increase the developer concentration; 2. Extend the development time of PS version. However, since the alkali-resistance of the PSA film of the PS plate is poor, it is easily eroded by the alkali solution and dissolved. Therefore, it is necessary to grasp the correct exposure time and reduce the erosion of graphic parts due to high developer concentration and long development time.

Second, the impact of development on the printing plate printing rate to increase the PS version of the printing rate, in addition to grasping the correct amount of exposure, but also pay attention to the development process on the printing plate printing rate impact.

The diazo compound of the photosensitive resin film of the positive PS plate is decomposed by ultraviolet light and becomes light-soluble light. In the process of development of the PS plate, the photosensitive resin film of the light-receiving portion dissolves in the alkaline form. The PS plate portion of the developer that is not affected by light cannot be affected.

The ideal developing effect is that after the PS plate is developed, the dots are clean, the plate surface is clean, and the unexposed part is not damaged, so that the blank part has hydrophilic properties. Therefore, in the development process to control three aspects: the concentration of the developer; the temperature of the developer; the development time.

PS version of the machine development: developer powder 56g, add water to 1000ml, developer ratio 1:7 ratio of water can be used.
Hand-developed: developer powder 67g, add water to 1000ml, developer ratio 1:7 ratio of water, you can use.
Groove development: consistent with manual development.

The concentration of the developer has a significant impact on the development process. Since the manufacturer of the PS plate has different properties and different performances, it is necessary to avoid the formulation of the developer solution. When deploying the developer solution of the PS plate, refer to the manufacturer's instructions for use. It is not possible to rely on feelings and experience to achieve standards. Positive PS version of the developer