Lithography in lithographic offset printing

The dots of the plate image are not normally zoomed out. Spreading. Blurring is called the paste version. In fact, they are a pair of faults - flowers and pastes - that appear in the opposite form. Such failures are also the most common in lithography. The phenomenon.

A flower version

In the printing of dots, the printing plate's internet point is reduced. The emptiness disappears. It is called the flower plate. The small line on the printing plate. The text disappears. It is also called the flower version. When the flower version occurs, the high-profile fine dots will soon be lost. Printed products, due to the foundation of the base of the oil-based destruction of the phenomenon of bleaching, also called the flower version.

The main reason for the flower version is the fountain solution and friction.

1. First, it refers to the amount of fountain solution and the acidity of the fountain solution. The amount of dampening solution is large, which will promote emulsification and aggravate, which will make the dot narrow, the fine dot will be lost, and the floral version will have strong acidity. result.

2. The friction of the printing plate is caused by the contact between the water roller, the ink roller, and the blanket. The size of the friction depends on the degree of parallelism between them. The size of the pressure and the surface condition. The friction of the printing plate is mainly determined by the friction. The water roller, as well as the friction between the blanket and the printing plate, is the largest. If the paper is heavily powdered during the printing process, it will aggravate the friction.

Second, paste version

The characteristics of the stencil are: enlargement of the layout of the outlets, mutual adhesion and merger, and the level of the printed matter is blurred. It is mainly reflected in the low-key part of the image.

There are many reasons for producing paste version. The main reasons are water delivery, ink transfer and pressure.

1. The control of the water delivery system is closely related to the stencil printing. With a small amount of water, the ink can easily expand, spreading the outlets, and can cause stencil printing. The loss of large amounts of ink and emulsification of the ink can also cause stencil printing. The emulsified ink is poor in oiliness, so that it floats freely to the fountain solution. It first expands outward at the low-medium-medium outlet to form a paste.

2. Too much ink is one of the basic causes of stencil printing. Because the ink volume will inevitably cause network expansion, over time, it will form a paste version. Too much ink is also the cause of the weight of stencils. Thin ink flow If it is too big, after being squeezed, it will produce a paste phenomenon.