How to solve the problem of ink marks in flexo printing

How to solve the problem of ink marks in flexo printing?

Is the printer with a squeegee? Is it a darker ink bar or a lighter colored ink bar? I have the same problem. If the anilox roller does not have a squeegee, check the roundness of the rubber roller, the wear of the roller gear and the bearing, and check the anilox roller if it has a squeegee blade. Machine oscillations also produce ink sticks.

We use the machine foot Heidelberg GALLUS 410. Anilox rollers, stainless steel squeegees and machines are new and there are no vibration issues. The color of the printed products is one deep and one shallow, especially the deep blue printed on the ground.

Your problem is probably caused by gear meshing. It is also a toothed bar. It is easy to appear when the gear bar has a low speed. It should be said that the machine of GALLUS is helical gear meshing, and the chance of occurrence of gear bars is small. As far as I know, helical gears certainly do not have ink sticks at high speeds, but at low speeds, it is easier to produce ink bars than straight teeth, and it is difficult to eliminate the ink bars by changing the meshing relationship of the gears. You can try to see if there are no ink bars at 80 to 90m/min. Then make a judgment.

At least you say it's obvious when printing dark blue on the ground. Actually not the printing color is different, the size of the ink stick will be different. There is a saying in the printing industry that "blue ink does not hide ugliness," which means that when printing, a slight problem with blue ink will appear ugly. The same is true for green ink.

We used two plates, 164 teeth and 159 teeth when printing the same product. With the 159 tooth plate roller there is no ink bar and there is 164 teeth. What's going on here?

This will be divided into two scenarios:

If your product is the same and only a different version of the roller is used, the number of gears with a larger number of teeth must be more in the neutral position of the platen. For example, if you print a Red River soft pack, 159 teeth can be completely wrapped in one week, and the neutral position of the edition mouth may be only one point, such as l0mm. When you use a 164 tooth roller, your neutral position becomes 10+3.175 x (16+4-15.9)=25.8m. Then when the plate roller rotates one revolution, it will be more than twice the time in the neutral position. To know that this extra space, the roll rotation may be unstable, it is not surprising that the ink stick is generated. Solution: 1. Bold balance line: 2. Paste off the solid ground from the waste plate in the neutral position, and use it for the vibration generated by the balance roller during rotation. 3. The pressure should not be large.

Second, if the two sets of roller prints do not have the same graphics, you must first eliminate the first reason. Second, you can observe when your cross cutter blade comes into contact with the bottom roller. If it is, then the reason for the ink stick is definitely because of the vibration of the cross cutter. This kind of vibration has a very large effect at low machine speeds. Solution: 1. Lower the blade of the cross cutter to just cut off the paper as well. It is better to produce vibration. This may require a little patience and skill; 2. Increase the speed of the machine to above l00m/min. There is no ink bar; 3, the printed paper through the paper to change the line, so that when the cross-cutting knife, the version of the port on the roller is just in the printing of the binding position, that is, it does not give it an ink bar Opportunity, we call it "the knife bar."

I don't think that the saying that a die cutter roller vibrates to produce an ink stick does not necessarily make sense. The position of the die cutter is more than five meters away from the location of the printing unit that produces the ink bars, and our machine has a rotary screen that can only reach up to 60 m/min.

Die cutting (or slicing) production of ink bars has been confirmed in production. The phenomenon is that there is only one or two prominent ink bars on a printing perimeter. As for the interval of five meters you said, if the speed is low, the vibration of the knife will surely have an effect.

Bearing damage can also produce ink bars. I would like to ask what kind of ink bars are produced by bearing damage. What type of bearing is best for flexo presses?

Bearing wear or damage is also an important cause of ink sticks. The mandrel type flexographic printing machine is generally used, and the roller bearings used in the version are all ball bearings, and there are no special requirements. Roller bearings are generally used for integrally mounted flexo roller bearings. At present, most imported flexographic presses use a mandrel type, and roller bearings are not easily damaged. The bearings upstairs brothers may refer to the pressurised bearings in the flexo press clutch mechanism. It is generally a fall-shaped bearing and it is easily damaged. Slight wear results in serious ink bars.

The machine I use is an old-fashioned flexo machine. The anilox roller does not have a squeegee; the amount of ink is controlled by the squeezing of the rubber roller and the anilox roller, and ink bars have frequently appeared recently. It is very obvious when driving at low speed, but the ink stick phenomenon will be less noticeable because the ink volume will increase automatically at high speed. For this old-fashioned machine, is the damage to the rubber roller the main reason for the generation of ink bars?

ABS engineering plastics are used as the material of the anilox roller gears and plate roller gears. Then divide the gear into two, clamp off a bit (how much is staggered in relation to the gear module) and tighten the separate gears with screws to eliminate the gear transmission gap and eliminate the gear bars.

According to what you said, the ink bars should be caused by the unevenness of the roller. The solution is to take the roller and turn it over. Rubber roller is best used with self-aligning bearings, such as: 1204, 1205, 1206 and so on.

The ink bar is mainly caused by the unsuitable or non-parallel pressure of the anilox roller, the plate roller, and the embossing roller, and can be solved by using a feeler adjustment.

Can an anilox roller produce an ink bar? In the printing process, ink bars appear in the middle of the layout, eliminating the accuracy of the roller and the pressure position. The equipment is the Andy 4150.

The anilox roller does not produce ink bars (no vibration and gear damage on the machine). The problem of gear accuracy will produce a toothed bar, which is to distinguish between an ink stick and a toothed bar.

Anilox rollers do not produce ink bars. You can see how much the difference between the diameter of the anilox roller and the plate cylinder is different. Try a different version of the platen roller. Also look at the viscosity of the ink. If the viscosity is too high, it can be thinned.