Ningbo Smile tools Co.,ltd , https://www.nbsmiletools.com
Replacing the water roller flannel is a waste of time. Therefore, the operator should prepare a spare water roller for replacement at any time. During the operation of the printing press, dirty water rollers can be replaced and cleaned. When cleaning the water roller sleeve, the water roller flannel must be carefully. The tightness of the water roller flannel should be kept even along the length of the roller. The amount of sag at both ends should also be equal. After the knot is knotted, the ends are flat and should not be It is a circle.
If the roller is removed from the press, the roller should be held in the correct orientation when installed again, and the two ends cannot be placed upside down. Otherwise, wrinkling of the paper roll cover or fleece of the water roll can be caused.
Regardless of the coating material used, as long as the water roller sleeve is changed, the operating diameter of the water roller will be changed, and accordingly, the setting of the water roller should also be checked, and if necessary, appropriate adjustments may be made.
3. Preparation for printing plates before storage. Some types of plates require a layer of printing plate glue as long as the press is down for more than a few minutes. (This glue may be gum arabic, or it may not be). Plate manufacturers can recommend appropriate plate protection adhesives to printers, and printers are also advised to use the protective tape recommended by the plate manufacturer. For example: Asphalt-gum etch (AGE) may cause poor inking in certain graphic areas on the plate.
A thin layer of glue (the type of glue to be determined depending on the condition of the printing plate used) can protect the printing plate and prevent oxidation of the surface of the plate (oxidation may lead to paste). In general, the rubberized plate has better adaptability and the speed of ink and ink balance is faster. If the printing plate is installed on the plate cylinder, since the space on the printing machine is very limited, it is inconvenient to conduct the gluing work. At this time, the printing press personnel can quickly stencil the printing plate, and in the subsequent process ( For example, in the next printing process), the plate is then scrutinized on a large work bench.
Usually, the plate mounted on the printing press is first wiped with a sponge impregnated with glue, and then the surface of the plate is evenly wiped with a soft, damp cloth. If the amount of glue applied is appropriate, it will not cover the image area on the plate (the surface will also carry ink); if the glue is excessive, the graphic part will also be covered with a very thick layer of protective glue, blocking the solvent from passing through and May cause poor ink.
After the coated glue is dried to form a uniform layer, the ink in the image area on the printing plate is wiped off with solvent, and the plate is covered with paper to prevent the printing plate from being scratched.
(2) Check and compare the inspections of the manuscripts, plates, papers and inks with the detailed descriptions listed on the worksheet. If there are any differences, the workshop director should pay great attention at once. In general, this check should be done before the end of the previous job print, which is also part of the preparation.
(c) Setting up a paper control device
This work is more time-consuming. In general, all settings need to be adjusted if the size and thickness of the paper are changed. Some of the newer types of printers have devices that automatically adjust the paper control device. When the size or thickness of the paper being used is changed, the device can automatically adjust the corresponding paper control device.
When replacing paper, some typical steps for manually setting the paper control on the press include the following:
A, place a pile of paper, and put the paper on the printing machine's pile table.
B, adjust the different components of the paper separation unit: paper stack height regulator, separation brush, rear suction, front suction foot, and hair suction nozzle.
C. Adjust the various components of the paperboard, including: paper feed rollers, double-sheet detectors, continuous paperboard devices, suction devices, and front-to-back detectors, among which the continuous paperboard device includes many components, for example, pressure Tightening rollers, conveyor belts and brushes, etc. It is responsible for sending the paper to the front gauge.
D. Adjust the front gauge and side gauge.
E. Set the stoppers of the grippers and the impression cylinder, and if necessary, compensate the images on the printed product as recommended by the printer manufacturer.
F. Set the pressure value of the impression cylinder according to the thickness of the paper used.
G. First print a test on the printing press, and set up the paper catcher, the auxiliary delivery device (function to slow down the paper), and release time of the gripper.
Repeat the above steps until the paper passes through the printer smoothly. In order to ensure that the image overprint is accurate, the position of the side gauge and the feed table must be slightly adjusted.
Due to the different number of press operators and the structure of the press itself (some printers have automatic or semi-automatic loading devices), the installation steps of the printing plate are also very different. In most cases, an operator stands between the printing units. Another operator hands him the plate and installs the plate. No matter what steps are taken, every operator must know how to safely use the jog control of the press.
The basic operation is as follows:
a. Check whether the plate to be installed is correct against the production task list.
b. Check the quality of the printing plate and the quality of the graphic.
c. Measure the thickness of the plate with a screw micrometer and prepare the pad (if necessary to adjust the length of the print, make the necessary compensation in the pad).
d. Check whether the back of the plate cylinder and plate is clean and clean. Adjust the plate cylinder and plate clamp to their starting position or “zero pointâ€.
e. Install printing plates and pads on the press.
Keep the following three points in mind when installing a plate:
a. The size and thickness of the gasket should be correct;
b. Make sure that the tension on all screws is the same, and that the plate is fully affixed to the roller;
c. Be sure to align the plate with the pre-registered marks and rules.
Sometimes it is necessary to twist or bend an installed plate to reposition it to a pre-designated location. If the printed image is not completely parallel to the paper (or the color printed in front of it), the plate must be repositioned and positioned. Repositioning the plate is always better than adjusting the former. The basic steps to reverse the printing plate are as follows:
a. If the printer does not have pre-registered marks and rules, use a pencil to draw a line (from the plate to the cylinder);
b. Determine how far the plate should be twisted to be able to make the image parallel on the paper and draw a new mark on the cylinder. Note: Torsion can damage the plate.
c. Loosen the tension bolt on the tail clamp and drag the plate forward to the proper position.
d. Use the bolts on one side of the plate cylinder to push the tail clamp sideways, and the distance from the printing plate is the same.
e. Tighten the tension bolts on the jaws.
f. Tighten the tension bolt on the tail clip.
1, automatic loading. In the past few years, some printing press manufacturers have added automatic or semi-automatic loading devices to printing presses. Depending on the degree of automation of the plate assembly and the different manufacturers, the operating procedures and operating methods of these devices are also different. Therefore, it is advisable to refer to the corresponding operating manual when operating. The basic operation of the automated plate system includes the following steps:
a. The operator puts the new plate into the plate box.
b. The operator selects the printing unit that needs to install the new printing plate, and presses the button to start loading.
c. The safety protection device is automatically opened, and the rear of the plate loading machine is close to the plate cylinder.
d. The plate clamps open, releasing the old plate into the plate loading machine.
e. The plater inserts the new plate into place and installs it on the plate cylinder.
f. When the printing plate is closed, the plate loading machine is returned to its original position, and the safety protection device is also closed.
2, cleaning and wetting system. Although the ink cleaning agent can be used to clean certain types of paper water roller sleeves, it cannot be used to clean the wetting system in general. In addition, if the water roller is covered with a water roller cover, there is a lot of capillary due to the water roller fleece. Holes will absorb a certain amount of ink solvent, which may cause its hydrophilic properties and water transfer effect to be reduced. Therefore, the wetting system should be cleaned with a suitable cleaning agent, and it should be thoroughly rinsed after cleaning.
December 31, 2023