Printing management must be consistent in the packaging printing process

Lithography is mainly two processes of plate making and printing. This is an organic whole. The quality of any link in the process of plate making directly affects the quality of printing.
The quality of printing is to take a new situation in the quality of printing itself, and second, to take a new situation in the quality of the plate. Therefore, platemaking and printing are inseparable and complete unity. At present, we all divide platemaking and printing into two different units. Therefore, in production operations, the business department in charge of production should coordinate the relationship between the two. This point is increasingly important. Doing this well will not only facilitate the implementation of the production plan, but also contribute to the improvement of product quality.
In our printing and production units, the separation between plate making and printing is too obvious, the boundary is too clear, and the plate making people do not understand the printing. The printing does not understand the plate making. The printing factory (team) is to be centered on printing, and the platemaking must be a printing service because the printed product is the final product.
The print sequence of map printing is generally black-brown and blue-green. In this way, the dark color comes first and the light color comes later. The main elements are in front, and the minor elements are in the back; the dot area is small in front and the dot area is large in the back; the darkness of the ink is dark in front and bright in the back.
The color sequence of proofing should also be unified with the above color sequence. Especially in the printing of other color paintings and field photos (such as topography and other pictures), we must emphasize the consistency of proofing and printing color sequence. If the proofing and printing color sequence are not uniform, there will be problems that printing cannot catch up with proofs.
In the printing of print and field photos, the printing sequence is unified: black-blue-magenta-yellow. This is conducive to highlighting the outline of the black version, stabilizing the tone at the bottom, and contributing to highlighting the main colors.
The reasons for the gap between print and plate making and the difference in printing and proofing are proposed. Some methods for reducing the difference between printing and proofing are proposed:
1, proofing is usually used thicker, more white copper plate, small deformation, high precision, and beautiful. The printing is mass production, and the use of paper must consider various factors such as cost, paper deformation rate, whiteness and so on. This makes it impossible to use thicker, whiter copper alloys. In order to reduce the difference between printing and proofing, printing must be considered when proofing, and the use of paper and printing should be the same.
2, color order problem. Usually considered in the proofing is the convenience of washing the ink, generally first light-proof, after proofing dark. In printing, the opposite is true. The main color (black) is printed first and the second color (green) is printed.
In order to reduce the difference between proofing and proofing, proofs must be taken into consideration when proofing, first proofing dark, and after proofing light colors.
3, overprinting method: proofing is wet and dry, that is, the ink after the first proofing for a period of time, the ink layer is moderately dry, and then proof the next color. The printing is wet and wet, the printing time is very short before and after, and the ink layer is too late to dry. For this problem, only a few colors are sampled in a timely manner at the time of proofing.
4. Imprinting method: When the proofing is round and flattened, and printing is a round pressurizing circle, under the same pressure bar width, the compression amount of the circular press is twice as much as the round press proofing machine. Therefore, when adjusting the printing pressure, the press bars of the two machines cannot be adjusted to be the same, that is, the thickness of the lining should be adjusted.
5, printing and proofing speed is different, so the paper and ink adhesion, paper and roller on the ink peel force are not equal. The speed of the proofer is low, and the roller, ink, and blanket have little peeling force on the paper, and the type of ink used for printing is thick, the dots are smooth, the expansion value is small, the layers are rich, and the contrast is large. The printing press has a high speed, generally at 8,000 printing/hours, and the contact time between the printing dots corresponding to the particles is reduced.
As the peeling force of the ink on the paper increases, the transfer of the ink volume is reduced, so that the spot is not true, and the dot is not strong, reflecting that the printed ink layer is thin and the contrast is small. To reduce this difference, from the printing point of view, we must properly control the speed; use a hard lining; 昼 reduce the amount of dampening fluid. This reduces the peeling force, thickens the printed ink layer, reduces the dot gain, and increases the contrast.