Common paper failures during the hottest printing

Common paper faults in the printing process (Part 2)

3 large crooked pleats

reasons for this kind of pleats

(1) the edges and corners of the paper are cocked up due to heavy water, and the paper teeth are not good

(2) the holding force of the paper teeth at one side of the paper is too light

(3) the corners of the paper float

(4) the side gauge is improperly positioned, and the paper corner touches the notch of the paper gripper

processing method: print on the machine after the paper is knocked back; The looser paper teeth need to be readjusted. In fact, the gap between paper and developed countries is not very large. The main reason is that the teeth can't hold the paper

(Figure) large crooked pleats

[case]

a factory j2105 machine prints middle school textbooks with color inserts. 128g/㎡ coated paper was used for printing. Shortly after the official printing, it was found that pleats occasionally appeared outside. After careful observation, it was concluded that when the paper was pulled by the side gauge ball, the paper corner collided with the gap of the paper feeding tooth table, resulting in pleats

treatment method:

the side gauge shall be shifted appropriately to avoid the gap

[expert tips]:

similar to this phenomenon, the captain should deal with it in advance, and cannot deal with it again until the problem occurs

4 circular pleats

the main reason for this kind of pleats is that the middle part of the paper teeth is too loose, resulting in the phenomenon that the paper cannot be held in its mouth, and pleats are pulled out during printing

treatment method: correct the gripping force of the paper teeth. If the tooth pad is too smooth, replace it with a new one

figure arc pleats

sub

[cases these products not only drive a substantial increase in plastic demand]

a factory printed an enterprise advertising brochure with a four-color offset press, and found that arc pleats appeared in the place where the portrait was printed in the latter half (not every one)

[case analysis]:

according to the conventional treatment method, it is necessary to check the gripping force of the paper teeth, but in this case, the gripping force of the paper teeth is good. Later, it is found that the part with wrinkles will be protected, and the black density of the spot check position is large, especially the red ink density is too large, resulting in the increased peeling force here, and the above failure will occur if the paper teeth are slightly inappropriate

treatment method:

remake the plate, put the portrait in its mouth or the front half of the paper, and the fault disappears

[expert tips]:

generally, for products with strict requirements for portrait or fitting, such as portrait or small picture, it is best to put it in its mouth or the first half of the printing paper when making up 2 The platform for the production and utilization of new energy automotive materials. In addition, those with high ink density should not be printed in the back half

5 large sporadic pleats

reasons for this kind of pleats

(1) there are two or more paper teeth in one place of the imprint drum, which are too loose to hold the paper

(2) the paper delivery tooth pad is uneven, so that the edge of the paper in its mouth is not in a straight line and becomes a wavy curve. When the imprinting cylinder holds the paper in its mouth, the length of the paper is shortened, and large loose folds are generated from its mouth

treatment method: check the holding force of the paper teeth of the imprint cylinder

figure large loose hair pleats

source: Ke Yin