Lithography suitability (on)

To adapt to the quality of printing and copying, processes and technologies for manuscripts, copying, printing, processing and binding, and various materials involved

All requirements for materials, equipment, environment and related conditions, in order to obtain the best quality of all operations.

Second, the relationship between printing and fitness

(a) Letterpress printing: The printed part is indented, and the imprint is surrounded by a framed edge. Suitable for a small number of forms, business cards, envelopes, stationery, self-adhesive stickers or sleeve numbers

Coded text or simple illustration prints.

(b) Lithographic printing: The printed lines are not convex or concave, and the lines are fine and delicate. Suitable for black and white and color books, color magazines, posters, advanced stationery,

Multi-color prints such as paper boxes, calendars, newspapers, etc.

(3) Gravure Printing: There are two kinds: 1. Gravure-engraving: The printed part has a protruding feeling when touched by hand, and the ink is thick and strong. Suitable for securities,

Printing of banknotes. 2. Photogravure - its imprint appears to have a faint dot-like appearance, also like continuous tone. Suitable for large circulation of color miscellaneous

Zhi, plastic film, aluminum foil and other packaging printing.

(d) stencil printing: imprinting into burrs and thick ink layers. Hard and soft printed objects suitable for plane and curved surfaces, including plastic surfaces

Newspapers, printed circuit boards, local glazing, transfer paper, fabrics, etc.

(5) Non-engraving printing: The printing methods applied by electronic means include the use of dry type toner and liquid type ink. The former has a slightly convex pattern on the printed pattern.

The latter is similar to lithography. Suitable for small lot, medium and low quality color printing or color printing.

Third, the manuscript's suitability

(i) Texts, ideal conditions should include:

(b) The form draft, ideal conditions should include:

(3) Drawings such as charcoal paintings, Chinese paintings, oil paintings or watercolours, ideal conditions should include:

(d) positive or photo, ideal conditions should include:

Fourth, the appropriateness of the replication technology

(1) Text reprint: Due to the different types of manuscripts, there are printed on paper, written on molded paper, handwritten on burrs or other papers.

Zhang Shang, its reflectance is not the same. Special attention must be paid to the revised exposure time when copying. Followed by the naked eye and the copying of the camera

If there are often slight differences, it will often take time and experience to do a good job.

(B) black and white scan over the network: As the density of the original document often can not match with the scanner, over the net must pay special attention, especially from bright to dark

Concentration and curve values ​​(or gamma values), or bright and dark-tone photographs, are all different due to the operator's technology, and there will be a considerable difference in quality.

do not. Therefore, at the time of adjustment, it is not difficult to obtain a perfect reproduction by paying attention to and comparing quality differences between manuscripts and reproductions.

(c) scanning and separation: the control of color and gray balance, as well as the control and adjustment of the light division and sub-light division adjustment, all require some experience.

Can do it well. Sometimes the need to make local color corrections is a difficult operation. It takes many years and months before the operation can be handy.

(D) manual imposition: Before the imposition must first consider the binding method, because the different binding methods, the number and order of the imposition will also be different, and glue

The order of loading, hardcovering, and paperbacking is the same, but the distance between the back and the back is not the same. Before the imposition, the binding method must be decided so that

With the arrangement and imprint. In the collage, one page should be used for the entire collage. It is not allowed to cut in the film so as to avoid streaks during printing.

The situation is not easy to find in the platemaking process. When it is printed on the machine, it is found that using chemical liquids or grinding off with a pumice pen is not only a waste of time, but also

It will damage the layout, and it will damage the layout, and sometimes there will be other problems.

(5) Computer group pages: Although this equipment is the latest, there are still many printing factories that do not have the ability to purchase such expensive facilities except for a few large factories.

Preparation, although it is fast on the job, but can not be modified after the output of the film, otherwise you must re-release the film, will increase a lot of costs. Therefore, in the country

More often than not, it is used to make a small version without using it. The big version still uses manual imposition. Since this operation depends on computer equipment,

Input, storage, editing, calculation, output, and auxiliary devices are different because of their different software systems, but the basic principles are similar.

Fifth, the suitability of printing technology

Lithography is very different from other formats. Other formats are mostly direct printing, that is, physical printing in which the printing plate is in direct contact with the paper or the printed body.

Brush way. The lithography is a chemical printing method using the principle of mutual exclusion of water and ink. Therefore, the applicability of other technologies is quite different from other formats.

(a) stack of paper: It should be noted that the cross-threaded paper can not be mixed together, the entire pile must be a consistent stream, otherwise it will produce paper due to the expansion of the paper

Changes in color, product quality will not be consistent.

(B) Ink balance: Since the lithographic printing machine must have a wet system to provide layout water. There are three types of systems:

1. Traditional water system.

2. Semi-alcoholic system.

3. Continuous alcohol system.

In order to make the distribution of moisture and ink on the printing plate average, an appropriate proportion should be adjusted to obtain the best printing quality. When there is too much ink

Caused layout pollution, too little will make the line drawing not printed or incomplete. Too much water will make the ink lighter, and vice versa.

ink. The alcohol system should pay attention to the composition and proportion of alcohol, and it also has a great influence on quality. Although these are very important jobs in lithographic operations

However, as long as it does not work for a certain period of time, it is easy to achieve the desired degree.

(C) dusting: There are two types of dusting devices:

1. Universal type.

2. Electrostatic type.

Regardless of the type used, the main function is still spraying a layer of thin powder on the dry ink to keep a little distance from the paper stacked on it.

Anti-printing occurred. However, special attention should be paid to the quality of the powder and the amount of powder to be sprayed. Poor quality or too much dusting will cause the next overprint or backside.

Poor ink transfer during printing, poor ink, poor printing patterns and so on. Too little dusting will cause the upper and lower papers to stick together

Such phenomena.

(d) Indoor temperature, humidity, and air flow: These are also the main factors affecting the printing quality. Although it is not directly related to the technology, it is like the printing machine.

Side, side due to changes in temperature, humidity and air flow will make the layout of water difficult to control. In the past, because of the cold air outlet on the top left of the printing press,

The airflow on one side of the printing plate is larger than the other side. Therefore, on the large airflow side, the layout water is easier to dry, and the operation of ink and ink balance is difficult to reach.

As a result, printing technicians are very troubled and cannot get good print quality.