2016-8-9 11:12:23 Click times：
At present, our metal packaging enterprises to use metal plate offset printing machine mostly two-color machine, high-speed four-color machine, six color machine is in the part of the enterprise of printing production, only a handful of monochrome machine still in service. But no matter what type, if in the production preparation process pay attention to a little or a link in the adjustment of improper, it will in the printing production produce misregister phenomenon. From production practice, we can see that caused by misregister from many reasons, so we should also from various aspects.
We first from the original point of view, electronic or photographic materials have their own color overprint error. Misregister is caused by factors from many aspects, because of the reason, operation on the device. Then plate in the car in school version of the operating uneven force tensile deformation can lead to the shortcomings of misregister, mainly in the size of the pulling force. In addition, the rubber drum pad will cause unreasonable overprint error. Thus, most printing enterprises on the blanket lining material has a clear set of standards, so that you can avoid blanket gasket resulted from the unreasonable of misregister. From the blanket itself, the quality level is not high and often poor elasticity, easy deformation of rubber blanket will cause overprinter error. Adjust the printing machine is the highlight of the overprint error. The first printing machine the parts precision is better. According to the requirements of the printing, the first printing plate must be positioned after the cross line, cross line plate are coincident with this. Regulation should grasp the following principles: 1, a gear positioning in order to stretch to drop, easy to adjust; 2, a printing plate adjusting direction and position should strive for consistency; 3, it should be take more loose and less pull way school edition, prevent excessive force caused by from the version of the clip and deformation defects; 4, a printing plate adjusting amplitude should master ahead, to the plate and cylinder attached to the left margin. Side regulation requirements to master two points: first, according to the thickness of the metal sheet, the appropriate adjustment of the spring force size; second, the rules of the distance between the metal plate and the usual control in 4-5 mm is appropriate.
Secondly, in the printing, three roller under the action of mechanical force, pressure changes caused by misregister, we call for general misregister; printing machine in operation there part of the damaged parts and careless handling of misregister, we call for the particularity of misregister.
General misregister, three roller pressure caused by changes in the operation of fingerprint iron machine "pumped up" phenomenon. The so-called "pumping up" refers to the printing plate cylinder and rubber cylinder after the cylinder with the impression of the same diameter of the impression cylinder, but the impression is not clear. "Pumped up" the reason is: 1, printing plate cylinder and rubber drum pad changes, resulting in changes in pressure; 2, blankets, poor quality, poor elasticity. "Draw up" should make appropriate adjustments to the printing plate and Blanket Pad pad.
The particularity of misregister, mainly iron machine parts wear fingerprints or failure caused by misregister. Can be summarized as follows: 1, a printing plate or blanket to improper installation; 2, spring pusher and push and pull the rules and the elastic force of the spring is the improper choice; 3, the tooth supporting cooperation coordination; 4, dental care and clip occlusion is unreasonable.
The blanket factor misregister, printing misregister and blanket of elongation is closely related. Blanket deformation for two reasons: 1, blanket and a printing plate and sheet metal contact friction force magnitude and direction; 2, blanket elongation. The size and direction of friction, blanket elongation, deformation degree is also different. The operation of rubber cloth and the quality and the degree of tension. Under normal circumstances, the rubber blanket stretched tight little elongation, imprinted changed little; elongation, imprinted pattern prone to "reprint" phenomenon. So that different quality or blanket is a blanket, the installation of the tightening degree of the difference of printing effect is not the same. In the installation of the blanket should pay attention to the following points: (1) rubber blanket has the characteristics of small elongation. (2) the blanket after tightening it is not allowed to change, to ensure the accuracy of registration.
The plate thickness changes and deformation of sheet metal and the smoothness effect of overprint accuracy. The printing plate, aluminum, the nature of soft, general installation will produce tensile deformation, affect overprinter accuracy. The tensile deformation of the printing plate: the plate under tension, its elongation value and the tension, the length proportional relationship, and the cross-sectional area and the elasticity is inversely proportional relationship. In other words, the length becomes larger; the elongation value is small, and the cross-sectional area and elastic coefficient are larger. Practice has proved that the blanket installation should pay attention to warp, prevent parallel radial and drum shaft. Plate itself is to rely on tension and fixed in the plate cylinder, and its elongation value will be changed. However, the tensile strength increases with the increase of elongation. So in the installation, try to reduce repeated tension and forcibly shoulds not be too big, general master in the plate and the plate cylinder attached stringent is appropriate. In addition, the rules have accurate judgments, error as small as possible. This can keep the stability of the printing plate, the rules and regulations to be mastered in the minimum range. In addition, the longer the plate length, the larger the value, especially in the larger size of the printing rules, the plate length is larger, the installation must consider the change of elongation value. Secondly, the plate thickness may not be the same, that is, the thickness of the plate material, cross sectional area is bound to be large. Under the condition that the elastic coefficient is constant, the tension value of the plate surface is constant. So to a certain degree of tension, the thickness of the plate more, its elongation value of the corresponding small, these basic knowledge for the Indian construction workers should glance in the heart. Another reason is the misregister plate deformation. A plate mounted on the roller is the first to be the role of tension. But the force of the point of dispersion, some of the force will be transformed into a positive pressure on the plate. In addition, the plate in the school is in the side of the shift, which has a friction with the surface of the roller, the tension and the angle of the roller also has a relationship. Printing machine cylinder radius is small, is it angle, a printing plate is stretched; conversely, the radius of the drum is the small angle, the plate is the possibility of tensile.
In short, the construction of the ills of printing misregister is one of the quality problems of printing production must be taken seriously. Printing operator only in the construction must be strict implementation of the technology, strict material selection, strict construction, in order to ensure the printing product quality stability, eliminated due to "misregister" caused by the adverse consequences.
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