Produce ink bars in offset printing (below)

In addition, when the pressure between the ink roller and the iron roller is too large, the iron roller will produce a squeeze on the rubber roller and the glue roller will temporarily deform due to its elasticity, which will cause sliding friction to the printing plate and cause ink bars. Moreover, due to the different pressures of the collector roller and the serigraph roller and the printing plate, it is easier to cause the surface line speed of their surface to be out of synchronization to cause ink bars. Therefore, the pressure between the rubber roller and the chain iron roller should be adjusted properly to avoid the roller being squeezed, and the resistance and the friction force are increased and the ink bar easily occurs. There is also a situation where the cohesiveness of the rubber roller is not good and not straight, and the ink bar is also prone to happen. This is because during the rolling process of the machine, the contact pressure between the rubber roller and the plate is inconsistent, and when the machine rolls, local friction increases to cause stripe marks. In this regard, high-precision ink rollers should be replaced for printing full-field and textured versions.
Similar to the ink roller caused by excessive roller pressure, there are some reasons in the printing that can cause the roller roller, and the principle is basically similar to the ink roller caused by excessive roller pressure. Such as: roller bending; roller expansion, cracking; poor cleaning; ink roller, water roller aging; ink roller shaft wall hole do not care; bearings, gears and other wear and tear; roller arrangement problem; roller bearing fulcrum problem.
4. Other In addition to the three conditions mentioned above, the reason why ink bars sometimes appear in printing production is really difficult for others to think of. Here we introduce some reasons that may lead to ink bars for reference.
Material: wrinkles of plate-making table paper; wrinkles on the underside of blanket; uneven thickness of plate; uneven thickness of blanket; remaining residual coating oil; wear of rollers and bearings on machine; excessive clearance of bearing support , The preload is too large; the bearings are skewed;
The use of upper plate cylinders or blanket cylinders is too large: If these two conditions exist, they will cause stripe marks due to inconsistent line speeds on their surfaces, and they will also cause shock chatter when the cylinders are imprinted. It is prone to friction and triggers traces of ink marks. In addition, sometimes the ink sticks are easily caused due to the inconspicuous imprinting of the mouthpiece (lower pressure) and excessive number of paper strips. In this regard, the thickness of the lining should be accurately adjusted, and the ink layer should be uniformly transferred with the minimum printing pressure so as to maintain the consistency of the line speed between the rollers as a precondition. When adding padding to the mouth part of the mouth, gradual padding should be adopted, and no padding should be added at once to avoid the appearance of ink marks.
The blanket is loose. If the blanket has just been changed soon, the stretching during the printing process becomes loose, and it is not tightened in time, so that sliding friction easily occurs during rolling, and thus a stripe-like ink stick trace appears. Therefore, when the blanket has a loose condition, measures should be taken to tighten it in time to prevent the production of printing ink bars.
5. Judgment and elimination after the emergence of ink bars We mentioned at the beginning of the article that the general appearance of ink sticks is very troublesome. The cause of the occurrence of bar marks is various and the situation is sometimes complicated. For one reason, there are also many kinds of unfavorable conditions that exist together; there are wear and tear caused by the parts and components of the equipment, and there are also misoperations and adjustments. Moreover, there are not many opportunities for the general ink bar to appear in production. It is difficult for the average operator to accumulate much experience in this area.
However, after careful analysis, we will find that the production and elimination of ink bars still have certain rules to follow.
1. The appearance of some parts of the ink bar is lighter than the normal part, and the general problem may be larger on the water roller.
2. When the ink at the position of the ink bar is dark, priority is given to whether the ink roller mechanism is normal.
3. When the ink bar is more visible at the mouth of the mouth, when the drag is less noticeable, give priority to the water roller or ink roller.
4. When the full version has dark and light streaks with a width of about 1 cm, it may be a problem with the gear (most likely due to gear wear or problems with gear spacing).
5. When the width of the ink bar is relatively wide and the position is relatively fixed on each print, it may be due to wear of the roller bearings or excessive roller pressure.
6. When the ink bar is relatively wide, its production may be related to the vibration of the machine.
7. If the appearance of ink bars is very regular, it may be caused to a great extent by the periodic vibration of a certain institution. Based on the spacing and position of the ink bars, further judgments can be made.
8. If the appearance of the ink stick is completely irregular, it may be caused by the loosening of bolts or the loosening and abrasion of the bolts at some place.
In fact, after understanding the causes and laws of the appearance of ink bars, the problem of ink bars in production will be solved much easier.
In fact, treating diseases is not as good as preventing diseases. In daily production, the emphasis is placed on strengthening the maintenance and the maintenance of equipment. Scientifically and rationally using and adjusting the machines to prevent and avoid opportunities for ink bars is the best way to deal with problems.