Pre-press Preparation and Test Printing Process for Album Printing
(I) Pre-press Preparation for Album Printing
1. Understand the Printing Process Requirements(1) Familiarize yourself with the standard sample (proof), including its color characteristics, main image features, and key technical requirements.
(2) Review the printing color sequence and propose modifications if necessary.
(3) Understand the main properties of the substrate material.
(4) Master the key characteristics of the inks and solvents used.
(5) Confirm layout design, dimensions, positioning, registration accuracy, and printing pressure requirements.
2. Preparation Inspection
- Inspection of Sheet-fed Printing Plates: Check each color plate for damage and ensure plate dimensions meet requirements.
- Plate Cylinder Inspection: Verify that the markings on each plate cylinder are clear, and measure their circumferences to select appropriate gear wheels.
- Bearing Quality Check: Ensure bearing clearance is within the specified range, bearings are clean, and lubricated.
- Substrate, Ink, and Additive Quality Inspection.
3. Cleaning and Inspection of the Printing Press
If the press has not been fully cleaned after a previous job, inspect and clean the following key areas:
A. Remove the roll shaft and check for damage.
B. Clean ink trays and ink fountains.
C. Flush ink pumps and hoses.
D. Clean ink rollers.
E. Clean plate cylinders and anilox rollers.
Adjustments to the Album Printing Press
(1) Parallelism Adjustment for the First Printing Unit:
- Plate cylinder and impression cylinder.
- Plate cylinder and anilox roller.
- Anilox roller and ink fountain roller.
- Measuring tool: Feeler gauge (0.05 mm thickness).
(2) Adjust registration for the front half of the press to ensure alignment marks overlap as required.
(3) Apply ink to the front half of the press.
(4) Adjust registration for the rear half of the press.
(5) Apply ink to the rear half of the press.
(6) Adjust ink roller performance to ensure even ink distribution and proper ink volume.
(7) Adjust web tension to maintain stability during printing.
Once the above steps are completed without issues, test printing can begin.
(II) Test Printing
The test printing process is as follows:(1) Start the press with the impression cylinder engaged for the first test print.
(2) Inspect the sample sheet for registration accuracy and print positioning. Make further adjustments if needed to ensure longitudinal and lateral alignment of the plate cylinders.
(3) Activate the ink pump, adjust ink volume, and supply ink to the rollers.
(4) Conduct a second test print.
(5) Inspect the second test print for the following:
- Color Density: If abnormal, adjust ink viscosity or change the anilox roller line count.
- Color Deviation: Replace ink if the color difference is unacceptable.
- Other Defects: Inspect and adjust as needed.
(6) Once qualified prints are achieved, conduct a small batch print run for final verification before full-scale production.
(7) During printing, monitor registration, color consistency, ink volume, drying conditions, and web tension regularly for timely adjustments.
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