Failure Analysis and Elimination of Imprinted Ghosts

Ghosting caused by too much ink viscosity

When the ink has a large consistency and strong viscosity, a slight slippage occurs during the imprinting process of the printed sheet, which can easily cause the occurrence of a ghosting failure. In particular, when the gripper has insufficient bite force, longitudinal ghosting is more pronounced. In this regard, as long as the ink is properly turned off, the ink is appropriately diluted, and the addition of additives to reduce the viscosity of the ink can eliminate the ghosting.

Plate is not taut or ghost caused by the "back pad"

At the time of loading, due to the lack of scientific operation knowledge, the fastening screws of the printing plate were not evenly tightened in order, so that the surface of the printing plate had uneven elasticity, localized traces of bowing, and the back pad of the printing plate was too soft. The use of multiple pads or pads to locally make the critical emptiness may easily lead to local ghosting. In this regard, it is necessary to close the screwing amount of each screw gradually and successively, by avoiding the operation of the good-fitting plate-laying technology and the pad-plate process technology. The child tightened it. Make the plate can not fully and evenly close to the surface of the roller. On the other hand, the pad used for padding on the back of the plate should be harder and try to avoid local multiple pads or hollowing in order to eliminate ghosting.

Ghosting caused by excessive printing pressure

When the pressure between the blanket cylinder and the impression cylinder is too large, the displacement of the blanket deformation will inevitably increase, so that the ink cannot be restored to the original state immediately after the ink transfer during the imprinting process, so that the impression is accepted from the plate cylinder again. At that time, a slight difference in position was generated and ghosting was formed. In this regard, as long as the roller pressure is properly reduced and the expansion and contraction coefficient of the blanket is reduced, this failure can be eliminated.

Ghosts or drums caused ghosting

When the blanket is tightly stretched, the force is not uniform, so that the local position is not tight against the surface of the drum, and an emptiness or a drum failure occurs, and when the back of the blanket is adhered to a multilayer pad or a foreign object, it is easy to make Partial layout imprinting ghost. In this regard, the rubber blanket should be released for inspection, and the bad impressions should be re-tightened to eliminate the impression of ghosting.

Ghosting due to incorrect clamping of plates or blankets

When the plate or blanket is not clamped, a slight loosening during the stamping process can easily cause ghosting failures. In this regard, as long as a careful inspection to take appropriate measures, you can eliminate the ghosting shadow failure.

Ghosting due to abnormal drum work

When the components related to the roller clutch pressure are not adjusted or each time the pressure is applied due to wear, a certain position difference will be generated, resulting in ghost images with different positions. In this regard, as long as the recalibration and adjustment of the clutch-compression mechanism and the repair of the worn-out parts are performed, the drum-disengagement-pressing work will be accurate, coordinated and uniform, and such failures will be eliminated.

Insufficient pressure due to paper pressure

When the roller teeth are worn and deformed due to wear, the force exerted on the printed sheets during the imprinting is insufficient, so that the printed sheets slide out of the teeth in the imprint during the imprinting, and the amount of each slip is not the same. At one time, the ghosting of the fistula area occurred due to the fact that there was no accurate overlap between the blurred blots retained on the blanket and the retransferred ink. In this regard, check the drum teeth, such as uneven deformation caused by lack of force, should be re-adjusted. If the crepe lines are worn and the edges are not tight, remove the new accessories to ensure that the paper is not slipping on the edges of the paper, and that ghosting defects can be eliminated.

Looseness due to looseness of roller gear or bearing wear

When the printer is used for a long period of time, the maintenance and repair work is not carried out seriously, which will cause serious wear of the roller gear or bearing. Inevitably, vibration will occur during the imprinting process. Imprinting will then follow. In this regard, after the worn parts should be repaired, the fault can be eliminated.

Dirty lining caused by roller lining

When the lining diameters of the plate cylinder and the blanket cylinder are too large, the speed difference and friction occur due to the inconsistent linear velocity at each imprint, which causes the surface of the blanket to be squeezed and deformed, and the inner liner material is easily moved. Until the wrinkles, blotting ghosting faults follow. In this regard, the center distance of the drum should be re-measured, and the thickness of the lining should be controlled according to the specifications of the equipment, and the roller line speed should be kept consistent to avoid the occurrence of ghosting and ghosting.