As a salesperson for a printing company, it is crucial to understand the entire printing process and know what products your company can produce in-house and what products can be completed through cooperation with partner manufacturers. Before printing, there are several basic areas of knowledge you must master. Today, I’m going to explain the process of prepress platemaking.
First of all, the primary condition for printing is plate making.
Understand the relationship between platemaking and printing:
Plate making is the means of printing, and book printing is the purpose of plate making.
Patternmaking involves color separation, while printing involves color synthesis. Color separation must be carried out according to the conditions provided by color synthesis, which means that the platemaking form is determined according to the synthesis conditions.
Conditions for color synthesis:
The three main elements of printing are equipment, paper, and ink. In order to meet the requirements of color synthesis, we must understand:
Equipment capacity
Paper properties
Ink performance
Next, let’s discuss the printing process.
(1) Pre-press preparation:
First, do three things: check the job order, check the handover book or production daily report, and compare it with the original to understand the entire printing process and operate according to the technical requirements.
Obtain necessary PS plates, paper and ink additives according to paper and sample requirements.
Adjust machine pressure according to paper specifications. For oversized products, equipment is adjusted as needed to ensure smooth production.
Determine the color sequence based on the color characteristics of the product to improve efficiency and quality.
(2) Printing process:
After mounting the plate, perform self-calibration to ensure that it meets the sample requirements: ensure that all corners are printed, the bite is consistent, the graphics are complete, the registration is accurate, the layout is clean, and the ink color is consistent.
For multi-color printing, pay attention to accurate registration. The main registration deviation should be less than 0.1mm, and the secondary registration deviation should be less than 0.2mm. Report any unresolved issues promptly.
Continuously check the printing quality during the printing process, compare it with standard samples, and correct color differences in a timely manner.
Strictly follow the work plan. For jobs with large ink coverage, use a pumping plate to prevent excess ink and ensure proper stack thickness to avoid print damage and scratches.
Consider the ink-absorbing and drying properties of special papers to prevent color fading or ink bleeding issues. For double-sided printing, make sure the first side is dry before printing to avoid contamination.
For spot color printing, match the sample color exactly. When formulating spot color inks, consider paper characteristics. Maintain ink recipe records to ensure consistent quality when reprinting.
Keep samples: Keep three print samples and signature samples after each printing. For book publishing, approximately 200 print samples of each page are kept to ensure quality.
After completing the handover procedure, the handover record must be kept for 6 months, and the quantity of each batch of products must be recorded for verification, and the plates must be cleaned and sealed for reprinting or reprinting.
(3) Product inspection:
Inspections are carried out item by item according to the product inspection level. For key products, it is necessary to conduct inspections one by one to eliminate defective products such as double sheets, white pages, crooked sheets, and excessive ink color.
Counting paper must be accurate. When counting hundreds, five hundred or thousands, slips of paper must be inserted. After counting, the quantity must be checked to ensure that the quantity matches the customer’s requirements.
Inspection method: Mainly adopts trigger inspection combined with piece-by-piece inspection. After regular defects are found during the inspection, they are inspected one by one until the problem is solved.
Handle genuine and defective products according to standards and keep records.
(4) Post-press processing:
Before operating each subsequent process, you must check the work sheet, originals and printed materials, and operate according to the requirements.
Specifications must be carefully checked before lamination to avoid wasting raw materials and using the wrong film to avoid waste products.
After the glazing is completed, the paper strip should be clamped and handed over to the subsequent process.