Among the professional knowledge of the most popul

2022-08-18
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Professional knowledge of lithography technology management personnel (middle)

III. detection lines, color codes and control strips must be prepared on the printing plate

1 Proofreading + word line: the standard of various color overprint, and the error should be within the range of 0.05 ~ 0.1 mm

2. Drag tip crosshair: located at the midpoint outside the drag tip tangent, it can distinguish between bite and drag tip, which is conducive to plate installation

3. Bite center line: it is located at the midpoint outside the bite tangent to distinguish the bite from the trailing tip, which is conducive to plate installation

4. Outer corner line: it is distributed 3mm outside the tangent line of the four corners of the printing plate, which is the basis of the corner size when the first color is calibrated, and it is also the standard for reserving the cutting position

5. Inner corner line: cutting line of finished product specification

6. Color code: located outside the tangent line on one side of the needle position, it is composed of four color blocks of yellow, red, blue and black, which are used to check the color leakage and needle position marks, which is conducive to the paper filling and beer cutting processes. For example, the speed of the high-speed train is about 300km/h

7. Control strip: comprehensively control the printing quality. Put it outside the trailing tangent

IV. requirements of printing operation on printing plate

1 Crosshair alignment, no error is allowed. Check with a magnifying glass. 

2. The size of both sides of the bite is consistent; The bite size meets the requirements of the printing machine

3. The blank part of the printing plate has no dirty spots and has good hydrophilic property

4. The ink absorption performance of the graphic part is good; The establishment of dianer tire development database provides a shortcut for the formulation of tire alignment plan, which is solid and smooth; The text is clear, without paste and broken lines; The field is flat and firm, without revealing the bottom line; It is even and flat, without uneven depth

5. It can reproduce the gradient of the depth and depth of the positive image

6. The detection line is complete.

7.15 times magnifying glass detection, 3% points are visible, and 5% points are just angled.

v. factors affecting the printing quality

version

the quality of PS version should be identified from six main aspects: sand mesh water storage, oxide layer quality, photosensitive layer quality, photosensitive performance, inking and hydrophilic performance

from the perspective of printing technology, PS version must have the following advantages:

the photosensitive layer has high resolution, rich layers, bright and solid dots, good ink absorption and transmission performance, good repeatability, wear resistance of oxidation film, good hydrophilic and oil repellent performance

for half tone printing plates, the printing resistance rate should be at least 50000

2. Printing light source

two factors should be considered for printing light source:

the emission spectrum should be consistent with the absorption spectrum of PS version as far as possible. The emitted spectrum can pass through glass

in recent years, the most popular one in the printing industry is gallium iodide lamp, whose radiation spectrum is 350 ~ 450 μ M. It is consistent with the best spectral sensitivity required by PS version

generally, it is appropriate to choose about 3000W, with increased wattage and relatively shorter exposure time

note that the lamp spacing adjustment complies with the provisions of the manual

3. Exposure time

generally controlled between 60 ~ 120s. (subject to the performance test of the used plate). If the point is small and the density is low, the relative time is short. Field, coarse and yellow are relatively long

two expressions for controlling exposure: 1 Exposure time. 2. Input the luminous flux

luminous flux f reflects the amount of light energy passing through a certain area in unit time, in "lumens"

illuminance e, the physical quantity that reflects the illumination degree of the object surface:

illuminance unit: lumen/m2, also known as lux

all kinds of PS plates have continuously adjusted printing scales to control the exposure

taking Huaguang version as an example, the control of drying machine version 5.2 the calculation scale of the total root mean square value of random vibration acceleration is: the first level to the third level of whitening; Photochemical reaction occurs in the fourth stage, and the density is blurred and diluted

national professional standards, print with the corresponding ladder:

the density value of the ladder is between 0.65 ~ 0.8, which should be retained and has inking property. If the density value is in the area of 0.35, remove it and whiten it without inking

at this time, all the print exposure is the standard and optimal exposure

4. Developer concentration, development time

developer is a weak alkaline solution. It should be controlled between PH10 ± 2 (reference value)

the development time should be controlled between 60s and 100s, which makes it difficult for the equipment to be backward. Too fast, difficult to control, small points are easy to lose, which affects the lipophilicity of the layout. If the speed is too slow, it is easy to cause incomplete development, and the blank part is easy to be dirty. The temperature of developing solution should be controlled in the range of 20 ℃ ± 2 ℃. Pay attention to fatigue failure and replenish fluid in time. (to be continued)

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