The effect of film on the quality of color box printing
The development and fixing process of film
after exposure is directly related to the sharpness and contrast of the image
on the film. Therefore, for plate-making film, the key is to see the density of
the graphic part and the contrast between the graphic part and the non-image
part. The higher the density, the greater the contrast, the better the quality
of the plate-making film, and the quality of the plate printing produced by it
can be guaranteed. In addition, the thickness of the plate-making film base
also has an effect on the quality of the plate making. Generally, the film has
a better effect than the thick film.
The effect of printing on the quality of
color box printing
In the process of printing, the intensity
of the light source, the distance between the light source and the plate, and
the length of the exposure time will affect the quality of the printing plate.
The light source is strong, the distance is short, and the exposure time is
relatively short; the light source is weak, the distance is long, and the
exposure time is relatively long. Under a certain light source and distance, as
the exposure time increases, the decomposition of the film of the plate
material is intensified until the film surface is completely decomposed. If the
exposure time continues to increase, the edge of the film surface of the light
is not visible due to the radiation of strong light, and the photosensitive
film begins to gradually decompose, so that the printed graphic lines will
become thinner, even broken and blurred. If the exposure time is insufficient,
the non-image part will not completely decompose the film surface, and there
will still be a film in the non-image part after the printing plate is
developed, and it will be dirty when printed on the machine. In addition, the
exposure time required for different brands of plates is different, which must
be noticed.
In addition, when the vacuum is applied to
the printing plate, the degree of close contact between the film and the
printing plate also affects the quality of the printing plate. If the sticker
is not applied, the printed printing plate may have problems such as ghosting
and blurring.
The influence of paper suitability on the quality
of color box printing
The suitability of paper is mainly
reflected in smoothness, whiteness and stiffness. Paper with a high smoothness
requires a relatively small amount of ink; paper with a poor smoothness
requires a relatively large amount of ink. In the printing process, different
papers vary according to their surface conditions, and the amount of ink
required changes accordingly. Under the same variety, same quantitative, and
the same price, the paper with higher smoothness and whiteness is better than
the paper with lower smoothness and whiteness.
The influence of plate suitability on the
quality of color box printing
The quality of the base plate of the plate,
the hydrophilicity of the metal plate and the lipophilicity of the surface of
the coated polymer resin are related to the suitability of the plate, affecting
the ink transfer and the balance of the ink on the plate. In the process of
plate making, the quality of exposure and development will also affect the
performance of the plate.
The influence of ink balance on the quality
of color box printing
Ink balance is a relative balance, not an
absolute balance. During the high-speed operation of the equipment, the graphic
part and the non-image part of the printing plate are both inked, watered and infiltrated,
so ink emulsification will inevitably occur on the printing plate. If the
amount of water and ink is not well controlled, it will inevitably deepen the
emulsification of the ink, resulting in paste and dirty plates in printing.
Printing is usually done by reducing the amount of water and increasing the
amount of ink, but sometimes it also reduces the amount of ink. In addition,
the ink emulsification will change with the change of environmental conditions.
In the actual printing production, the ink viscosity and the pH value of the
fountain solution should be well controlled according to the actual situation,
and the ink volume and water volume should be controlled. The paste version and
the dirty version are the benchmarks.
The influence of printing pressure on the
quality of color box printing
The
printing pressure refers to the interaction force between the plate cylinder
and the blanket cylinder, and between the blanket cylinder and the impression
cylinder, which is a necessary condition for ink transfer. The printing
pressure is too small, the ink is not easy to convey, the ink is light and
faint; the printing pressure is too large, and the ink volume expands to the
non-image part, which makes the dot increase serious, the image is distorted, and
the printing plate and the blanket are easy to resist. decline. Therefore, the
mechanical pressure must be properly adjusted. Different quantitative papers
require different printing pressures, and only the proper printing pressure can
ensure uniform ink color and uniformity.
