The purpose of printing is to reproduce high-quality prints. The color registration and accuracy of printed images are very important index parameters for evaluating image quality. All along, people have paid enough attention to the quality of the dots before printing, and the transfer of dots in the printing process, and the dots on the film are transferred to the PS version. If they do n’t pay enough attention, they often even ignore some very important issues. Based on the experience of taking students to the factory for internship, the author currently ignores some seemingly simple but important copying issues at many factories as follows:
First, the correct operation of the transfer of graphic outlets from film to PS version
The domestically-used positive-working PS plate is used for this type of printing plate. The prepared photosensitive solution is applied to the surface-treated aluminum plate, which is heated and dried to form a photosensitive layer, which is made into a pre-coated plate and stored for later use. During printing, the photosensitive plate coated with the photosensitive layer is exposed to the positive film in close contact. The sensitizer in the visible part decomposes and emits nitrogen gas, causing cracking of the ring, rearrangement of the molecular structure, generation of indenone compound, and generation of indenic acid in water The compound is subjected to a development process to remove the photosensitive layer that has been decomposed by light, and the non-photosensitive area, that is, the graphic part of the plate, is preserved to make a printing plate.
We know that the contact quality of the film and the photosensitive layer of the PS plate is an important factor affecting the quality of the printing plate. The different contact conditions and the changes of the dots are also different. Good contact is a prerequisite for the controlled transfer of dot adjustment. During the operation, the face of the drug film should be strictly opposed, and the air can be tightly closed to ensure the good transfer of the graphic network. However, the situation of the drug film facing each other still occurs during production. Due to the thickness of the film base, light scattering will occur, the dot transfer will be uneven, and its change cannot be controlled. It should be strictly avoided. In daily production, there are many problems in this regard, as described below.
â‘ The plate making machine itself has poor vacuum contact, and the glass and rubber of the plate making frame are uneven. The rubber pad of a good printing machine should be raised in the middle, otherwise the suction will be offset; if it is not smooth, a woolen cloth should be placed in the middle to suck out the uniform.
â‘¡The pumping capacity of the vacuum pump is too low. A good plate-making machine can adopt segmented pumping, which is enough to ensure that it is closely packed and evacuated to make good contact.
â‘¢ Overlapping of 1 ~ 3 small pieces on the imposition film and sticking tape on the side of the picture, resulting in unsatisfactory pumping and partial edge of the picture. Inconsistent cropping of the film, the distance between the base edges of the film is different, resulting in different deformation of the spelling.
â‘£ Some of the original film and the plate have dirt, which causes the partial pumping to be not tight and the dots to become false.
In response to these problems, the author makes several suggestions:
1. Ensure the good working condition of the printing equipment to ensure that the air can be evacuated and the film contact is good.
2. Before printing, you should check the film carefully to minimize the overlapping of the imposition pictures and too much adhesive tape.
3. Check the glass, PS plate and film of the printing platform, there must be no dirt.
4. Add a diffuser film or diffuser, use segmented exposure or double exposure to reduce the film lines and dirty spots.
Second, the registration problem of the printed version
For a set of film, we will pay attention to their registration. When the picture and text are transferred to the printing plate, we will hand over the registration to the next process: printing. In fact, some operations in production often prevent the printed version from registering:
1. Film transfer occurred during printing.
2. The temperature in the baking plate is unstable or uneven, causing the printing plate to deform to varying degrees.
Due to the inaccurate printing of the printing plate, correction operations such as plate pulling are required during printing, which inevitably causes graphic distortion.
In this regard, the author believes that even in the imposition or production, even if you pay attention to the registration of the picture, you should not take it lightly when printing the printing plate, thinking that the printing plate must be accurately registered. Only strict process specifications can be printed. High-quality qualified printing plate. A good printing opportunity includes a plate punching positioning device, which cooperates with the plate mounting device of the printing machine to ensure the accuracy of plate registration. For example, Heidelberg has a professional printing positioning device, which cooperates with the automatic plate setting device of the printing machine to minimize the operation of pulling the plate during printing, which is almost unnecessary. When the long version of the work must be baked, the baking machine must be operated in a stable working state to ensure the uniform deformation of the PS version.
As the intermediate of image and text information transfer, the quality of the printing plate directly determines the quality of the printed image and text. Therefore, it must be fully paid attention to. It cannot be taken for granted that it will cause trouble for the printing operation and the image and text cannot be reproduced well.
This small plastic trash can is mainly made by Eco-friendly plastic PP or ABS. The living room garbage bin with press lid will easily replace the top open Wastepaper Basket in your home. Living room garbage bin with press lid can protect your room environment away from the bacterium and virus. Small plastic trash bin won't take up too much space of your room and easy to clean.
Room press type trash bin, Small plastic trash can, Living room garbage bin with press lid
ZHEJIANG ERHUI TECHNOLOGY CO.,LTD , https://www.jahhome.com