Some methods of troubleshooting ghosting shadows

Imprinting ghosting is one of the common faults in the printing process. Its production will affect the quality of the product, and it will result in the unqualified quality of the batch of products, which is unacceptable to customers. Therefore, only by accurately analyzing the root cause of the failure and accurately and quickly eliminating this failure can we ensure the smooth progress of production.

The so-called ghosting, also known as "double printing" or "double shadow", that is printed on the entire layout or a partial layout or a layout of the double outline of the footprint. From the phenomenon of ghosting, it can be seen that ghosting features vertical and horizontal double shadows. The reasons for this are both unilateral and multi-dimensional. Poor equipment accuracy, there are also technical operations, process discomfort, and so on.

First, the analysis of the situation caused by the longitudinal ghosting and exclusion method

1. Ghost caused by too much ink viscosity

When the ink has a large consistency and a strong viscosity, a slight slippage occurs during the imprinting process of the printed sheet, which can easily cause a ghosting failure. In particular, the gripper has insufficient bite force and the longitudinal ghosting is more obvious. In this regard, as long as the proper ink transfer process is turned off, the ink is properly diluted, and the auxiliary agent is used to reduce the viscosity of the ink, which can eliminate the double-image ghosting failure.

2. Plates are not taut or ghosts 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.

3. 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 accordingly, so that the ink cannot be restored to the original state immediately after the ink transfer during the imprinting process, so that the imprint is accepted again from the plate cylinder. 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, the failure can be eliminated.

4. Ghosts or drums causing 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 body, it is easy to make Partial layout imprinting ghost. In this regard, the blanket should be loosened for inspection, and the bad impressions should be re-tightened to eliminate the impression of ghosting.

5. Ghosting caused by improperly installed 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.

6. The ghost caused by the abnormal working of the roller pressing

When the parts related to the roller clutch pressure are not adjusted or due to wear, a certain position difference occurs each time the pressure is combined, resulting in ghost images that have different positions. In this regard, as long as the recalibration and adjustment of the clutch pressure mechanism is correct, and the worn-out parts are repaired, the roller declutching and pressing work will be accurate, coordinated and unified, and such failures will be eliminated.