Size adjustment of printing film

Printed film is used as a manuscript for producing printing plates. Its imposition precision directly affects the product's registering effect, and the registering accuracy is one of the important inspection indicators of product quality requirements. According to the CY/T5-1999 lithographic print quality requirements and inspection methods, the overprint tolerance for fine prints is ≤ 0.1mm, and the overprint tolerance for general prints is ≤ 0.2mm. This means that the imposition of the film as a basic condition must be absolutely accurate.

In the production process of printing products, when the problem of plate making is encountered due to imposing imposition, or the misprinting caused by printing distortion is not accurate, a slight adjustment must be made to a certain position of the printing plate. Make adjustments to meet the requirements for print registration. However, in order to accurately adjust the trace position of a layout in a film, visual adjustments are made to adjust the layout. The effect is not satisfactory. Especially the slight adjustment of the position of the layout, due to the inconspicuousness of the contour of the graphic text after the two-color film is superimposed, it is difficult to detect with the naked eye, and it is easy to cause misalignment. For example, if you want to shift a location to the left by 0.2mm, the result will be inaccurate because of visual errors.

In order to overcome this problem, we used the “dashing method” to achieve a fast and accurate adjustment of the layout of the film on two layers of film (the bottom layer is a transparent film base). The specific approach: the middle part of the film on the four sides of the layout will be transferred, and a straight line of fine line marks with a length of about 6 mm shall be drawn with a sharp knife respectively, and the drawn line marks shall extend to the base surface of the base film. In this way, the film to be adjusted in position has a position mark on the film base, and no matter which position the micro-displacement adjustment is made to, the film can be quickly and accurately adjusted by looking at the relative position of the film scratch and the scratch on the film base. The location on the base. The adjustment of the film layout is based on the results of the printing overprinting. That is, according to the actual overprinting condition of the printing, it is determined which one of the small plates of the negative film is to be adjusted, to which side the displacement, and how much. There are scratch marks on the film and film base, and the accuracy of the amount of adjustment has a reliable guarantee. In the production process of our factory, we must adopt the “dash method” to adjust the negative film or the printing distortion to adjust the position of the negative film, and received good results.

Source of information: pack.cn