Analysis and elimination of all kinds of ghosting

2022-10-14
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Analysis and elimination of all kinds of ghosting caused by imprinting

ghosting caused by too high ink viscosity

when the ink consistency is high and the viscosity is strong, a small amount of slip occurs during the stamping process, which is easy to cause ghosting failure, especially when the paper teeth are insufficient, the longitudinal ghosting is more obvious. In this regard, as long as the inking process is well controlled, the ink is properly diluted, and some additives are added to reduce the viscosity of the ink, the imprint ghosting can be better eliminated

the printing plate is not tight or the double image caused by the deficiency and reality of the "bottom pad"

when installing the plate, due to the lack of scientific operation knowledge, the fastening screws of the printing plate are not tightened evenly in turn, resulting in uneven tightness on the surface of the Baole cylinder of the printing plate, a small amount of bow shape in some parts, too soft padding on the back of the printing plate, or partial use of more or less padding under the condition of stretching and abetting the light to make it critical void, It is easy to cause local ghosting. In this regard, we should pay attention to the operation technology of plate loading and the technology of plate cushion, that is, when the printing plate Baole is tightened, the screw in amount of each screw should be tightened gradually and evenly, and we should not tighten a screw at once. Make the printing plate not fully and evenly close to the surface of the drum. On the other hand, when it reaches 54000 dollars, the padding used for padding on the back of the printing plate should be harder, and try to avoid local padding or hollowing out, so as to achieve the effect of eliminating ghosting faults

ghosting caused by excessive printing pressure

when the pressure between the rubber cylinder and the embossing cylinder is too large, the displacement of the rubber blanket's extrusion deformation is bound to increase, so the ink can't be restored to its original state in time after it is transferred during the embossing process. In this way, a small amount of potential difference is generated when receiving the print from the plate cylinder, forming a ghosting. In this regard, as long as the pressure of the drum is appropriately reduced and the expansion deformation coefficient of the blanket is reduced, the fault can be eliminated

ghosting caused by virtual loosening or bulging of the rubber cloth

when the rubber cloth is tightened, the force is uneven, so that the local position is not close to the surface of the drum, resulting in void or bulging, as well as local multi-layer padding or foreign matter adhesion on the back of the rubber cloth, it is easy to make the local layout imprint ghosting. In this regard, the blanket should be loosened for inspection, and the blanket should be tightened again after cleaning up the defects, so as to eliminate the imprinting and ghosting fault

ghosting caused by opaque, halogen-free, phthalate free, non-toxic, easy to process, flexible thermoplastic elastomer (TPE) particles when the printing plate or blanket is clamped

when the printing plate or blanket is not clamped, micro loosening during the stamping process is also easy to cause ghosting failure. In this regard, as long as careful inspection and corresponding measures are taken, the imprinting and ghosting fault can be eliminated

ghosting caused by abnormal drum closing work

when the drum clutch pressure related parts are not adjusted properly or there is a certain level difference during each closing due to wear, resulting in different imprint positions, causing ghosting. In this regard, as long as the clutch pressure mechanism is recalibrated and adjusted, and the worn parts are repaired, so that the drum clutch pressure work is accurate, coordinated and unified, this kind of fault can be eliminated

ghosting caused by insufficient pressure of paper gripping teeth

when the roller gripping teeth are worn and deformed, the gripping force of the printing sheet is insufficient during paper gripping and stamping, so that the printing sheet slips out of the gripping teeth in the stamping process, and the amount of slip is different each time. In this way, when printing the next time, the ghosting of the mouth is produced because the fuzzy imprint retained on the blanket does not accurately overlap with the ink transferred again. In this regard, it is necessary to check the drum teeth. If the clamping force is uneven or insufficient due to deformation, it should be adjusted again. If the paper teeth are worn and cannot hold the paper edge tightly, they should be removed and replaced with new accessories to ensure that the paper teeth do not slip when holding the paper edge tightly, and the ghosting fault at the mouth can be eliminated

ghosting caused by loose drum gear or bearing wear

when the printer is used for a long time, the maintenance and overhaul work is not carefully implemented, it will lead to serious drum gear or bearing wear, and vibration will inevitably occur in the stamping process, and the imprint ghosting will follow. In this regard, the fault can be eliminated after the worn parts are repaired

ghosting caused by improper cylinder lining

when the diameter of the lining of the printing plate cylinder and the rubber cylinder is too large, the speed difference and friction are generated due to the inconsistency of the linear speed during each impression, so that the surface of the blanket is squeezed and deformed, and it is easy to move the inner liner until it is wrinkled, and the imprint ghosting fault also follows. In this regard, it is necessary to re measure the center distance of the drum, control the lining thickness according to the requirements of the equipment specification, maintain the consistency of the linear speed of the drum, and avoid the occurrence of imprinting and ghosting faults

source: Guangdong Printing Factory

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