Offset press: standard operation of the whole machine

The standardization operation of the whole machine is in essence a comprehensive embodiment of the standardized operation of the six major alignments. The following takes the printing process of a printed product as an example to discuss the standardized operation of the entire machine.

1. Preparation before starting H

Before starting the machine, check the machine first, especially when operating the machine that has not been turned on for a long time or picking up someone else's machine. The main inspection area is the joint between the drum and the drum, the notch of the drum, etc. If there is any debris, it should be promptly removed. The sacred bucket and the ink fountain roller are also an important part of the inspection. One is to check if there is any debris in the middle, and the other is to check whether the ink fountain roller and the ink fountain blade are too tight. When the machine is idle, the ink fountain needs to be opened. In addition, check if there are any looseness in some important parts (such as paper-handling teeth, delivery chain, etc.). In addition, we must not forget the oil standard, especially those that do not have oil pressure testing. The unsafe items should be promptly removed on the paperboard, on the wall boards on both sides of the ink path, on the cover of the delivery area, on the footboard, etc.

After the above inspection, if the hand is used in a handcart, if the force is not uniform within one week, check the relevant parts in detail and then jog the machine. If there is abnormality, stop the inspection. After these tasks are completed, you can start up.

2. Start up

Before starting the machine, ring the bell first so that people around the machine can get ready for extraction. If there are more people, the ring time should be longer. To ensure safety, you should also observe around. Before pressing the switch, the other hand should be placed on the emergency stop switch. If there is an abnormality, the emergency stop should be performed (this judgment is usually based on the sound of the machine). Usually, the machine should be idled when it is on the surface of the printing plate, the blanket or the surface of the cleaning roller. The purpose is to make the surface of bearings, gears, cams, sprocket wheels, etc., have sufficient lubricating oil.

3. Sheung Shui, Ink

The amount of water used and the amount of ink applied depend on the specific print product. Generally, the amount of water and ink should be slightly larger than the actual demand (by experience estimation, the required amount can also be given by approximate calculation). When watering, care should be taken not to pour water on the outside of the water tank or the water tank so as to avoid dropping water on the machine and causing the surface of the machine parts to rust. When inking, the ink should be made to rest on the lowest part between the ink fountain blade and the ink fountain roller as much as possible, and it is not suitable to make the whole ink fountain everywhere. Sheung Shui and Sheung Shui should generally be carried out at the time of parking. If you are operating at boot, you must pay attention to safety. When the ink is applied, the ink and impurities in the ink tank should be removed.

4. On the plate, on the blanket

The blanket should generally be installed in advance. The suitability of the blanket can be judged by the sound of the hand. Use a rubber blanket on the middle of your finger. If the sound is crisp, it indicates that the blanket is tight. The sound is dull, indicating that the blanket is loose. Both sides should be carefully examined.

The plate should be mounted under pressure, so that the plate can be placed against the roller. For dry equipment that does not incorporate pressure on the plate, it is possible to set down the water roller. A detailed examination of the printing plate should be carried out before the edition. The specific inspection method is described above.

5. Even water, even ink

Start the machine and let the water and ink go into the water and ink roads and beat them evenly. If the amount of ink is insufficient, it can be quickly inked by pressing the ink bucket. After the water and ink are all evened out, press the water roller back on the printing plate to make the surface of the plate water first, after it is basically uniform (the surface water can be observed through the surface reflection), and then put down the printing roller . At this time, the ideal condition of the surface of the printing plate should be the reflection of the invisible water, and it is also a phenomenon of ambiguity. If there is reflection of water, indicating that the water is large, the amount of water should be reduced; if there is a paste version, it means that the water is small and the amount of water should be increased. In short, water and ink should be in balance.

6. On the rules line

The paper used at this time should be paper for rules. The usual way is to find some white paper in the waste sheets. Note that the overprinting paper should be basically the same as the blank paper to be printed (format, basis weight, category) until the rules are aligned. If the rules are not accurate, the rules can be made accurate by drawing on plates, borrowing rollers, and taking rules.

There are two points to pay attention to when looking for rules: When the 1 version is moving, the paper will not move, and the upcoming version will be pulled forward. Then the position of the graphic and text will move forward on the paper (in the same direction); when the paper moves (regular movement), the version When it is not moving, ie when the paper moves forward, the text moves toward the back of the paper (in the opposite direction).

The accuracy of the rules refers to the fact that the graphic and paper are parallel to the front edge of the paper and the side edge of the paper (pull gauge edge), and the entire graphic text can be printed on the surface of the paper, with the left and right substantially centered.

There are two ways to judge whether the rule line is parallel to the first four: First, fold the paper in half, make its rules line up, and see the degree of difference in the paper front mouth; second, align the front edge of the paper and see the relative degree of the rule line. After the beginner folds the paper, the two sides of the paper can be pressed together with a nail.

Judging whether the picture and the front of the paper are consistent or not, can be observed through the degree of phase difference of the rules. The usual practice is to pick up a sheet of paper with the side of the mouth as a reference, and then pry it sideways and measure the amount of difference. If you can't see the difference basically, you can think that it is qualified; if there are obvious differences, you need to analyze the reasons in detail (this problem is caused by improper adjustment of the rule).

Judging whether the side conventions are more accurate than the use of scribes. According to the position of the printed sheet on the edge of the paper, on the plate (pull gauge side), use the scribing hand to draw two lines (1mm apart from each other, so that the two lines can be printed on the printed sheet, and The first line on the page is printed on the edge of the paper. If this line is not printed on the other side, it means that the side rule is not pulled in place, and the size of the error can be estimated through the second line. You can use the dot method, but this mark is not easy to observe.It should be noted that after the line is drawn, the ink should be lapped (that is, the ink is applied on the scribe line, and then the excess ink is wiped off with a tarpaulin). We should always look at the rules line. If the rules are not accurate, it will bring great difficulties to follow-up work.

For monochrome overprinting, it can be done exactly as described above. For multi-color overprinting, a baseline should be selected first from among the colored rules to minimize the amount of adjustment without introducing other problems. After selecting the benchmarks, pull the other plates again so that the rules line coincides with the reference line of the datum, and then pass the rules to meet the requirements. However, the more standardized approach is to first meet the requirements for monochrome overprinting for all regulatory lines, and then to align the regulatory lines of the various color plates through the overall circumferential and axial movement of the plate cylinder. This method is carried out in the actual process as follows: advanced to a color plate closest to the requirements of the monochromatic rule line as a reference, through the pull plate to make it meet the required requirements, and then pull the other color plate close to the rule line. If there is a rule line parallel to the reference rule line, the rule lines can be overlapped by the overall movement of the roller. Double-sided overprinting should also be corrected according to this method, that is, one side as a reference, the other side and the reference plane overprint.