CN101054033A - Improved method for relief printing prepress production process - Google Patents

Abstract

The invention relates to an improved method for making process before relief printing. The original manuscript chooses the pattern which takes intermediate tone as the principal and avoids the pattern of light color, flat screen, gradual screen and large area dark color background; and printing graphic design modifies calibration black and white field via curve; amplification degree of screen node is 30% to 50%, and the thickness of the relief block ink layer can reach 30 mum m; screen node is corrected to truly duplicate the original manuscript; the making of printing plate needs to guarantee density of negative pattern, and blackness is required to be more than 4.0; correct exposure; adjusting output density and screen node linearization for laser phototypesetting machine; finding out best exposure time by using signal stripe during plate making procedure; avoiding small screen nodes loss. The invention has following effects: choice of intermediate tone pattern can avoid loss of the small screen nodes in noble part and class merger of the dark tone part. The invention can furthest duplicate the original manuscript, and has lowest printing error thereby reducing waste rate and saving cost and enhancing qualified rate for making plate.

Description

Improving one's methods of relief printing prepress production process

Technical field

The invention belongs to plate making, particularly a kind of relief printing prepress production process improves one's methods.

Background technology

Resin relief is printed on print field and belongs to new in recent years packages printing branch of rising.Rely on its early investment little, printing and seal back integrated process, printing is beautiful in colour, and order switches characteristics such as rapid and obtain high speed development aspect label printing.But the manufacture craft development of technology lags far behind the demand of industry developments such as IT, medicine, chemical industry before its seal.

Manufacture craft process before the seal: the selection-printing graphic design of original copy-forme is made.

Traditional method: on original copy is selected, apply mechanically offset printing sample or digital sample printing contribution.It is beautiful in colour that this kind way has exactly abandoned the letterpress middle tone, the full solid advantage in site.Make whole printing oppressiveness, tone variations is lofty, and picture is nature not.Traditional method: effective range and the dot gain rate of not considering the site level of letterpress.Indiscriminately imitate the universal law of offset printing picture and text design fully, carry out full contrast design.Cause 1% and 2% site disappear on the forme (even if 1% and 2% site is arranged on the negative, the printing opacity of site can not make the local enough sclerosis of resin plate, so that little site is removed when develop), make printed matter distortion, distortion.And shadow to 90%, be meant site more than 90% after printing almost completely and level, become on the spot.Even from 90% to 100% site can indistinctly be seen on the forme, but also be fuzzy a slice through printing figure message behind the last China ink, impression.Traditional method: depend critically upon plate-making operators'skills and experience, simply judge plate-making exposure parameter with film printing opacity light rate.Be difficult to reduce plate-making process percent defective and printing process scrappage in batches.

Summary of the invention

Technical problem to be solved by this invention is: improving one's methods of a kind of relief printing prepress production process is provided.

Technical scheme of the present invention is:

Selection-the printing graphic design of manufacture craft process original copy-forme is made before the seal.

Improving one's methods of a kind of relief printing prepress production process, it is characterized in that: the selection of original copy is improved one's methods: according to the characteristic of mode of printing and the characteristics of letterpress platemaking, the selection of original copy is selected to be adjusted to main pattern with the centre, avoid light color to a high-profile, the picture of plain net, gradual change net and large tracts of land deep dark background;

Printing graphic design is improved one's methods: in photoshop, by curve curve modification calibration black and white field; Usually, the black and white field of letterpress picture and text calibration scope is between 3%-90%, and the correction of every kind of color is between 5%-10%; It is the dot gain rate that the preceding picture and text of letterpress seal design another aspect; The amplification degree of relief printing plate site is at 30%-50%, and the thickness of relief printing plate China ink layer can reach 30um, that is to say the color density height; The site of carrying out on original copy is revised, and reaches the true copy original copy;

The making of forme is improved one's methods: at first will guarantee the field density of negative film, use the densimeter measurement film density, require more than 4.0; In qualified density range correct exposure; Next requires the computer RIP system of the laser photocomposing machine of slice to adjust, and both output density adjustment and site linearisation were adjusted; In the plate-making process, to find out best exposure time at last with signal strips; Avoid little screen nodes loss.

Effect of the present invention is:

The selection of original copy tells on: the letterpress contrast is short, and the also level at the loss of little site, high light position and shadow position makes picture lose level when selecting the middle tone pattern to avoid printing, fuzzy a slice.Select the middle tone original copy farthest to carry out original copy and duplicate, the error that printing is caused is minimum, and the rate of reducing the number of rejects and seconds is greatly saved cost.For the high light original copy of light color, because there are the blank and 1% of exhausted net, 2% little site in high light position, select the middle tone pattern can avoid the loss of little site, make picture transition nature, reduce the destabilizing factor in the Plate making printing process, the generation of effectively avoiding the batch printing to scrap.Printing graphic design tells on: improve plate-making process qualification rate and the new product first-time qualification rate of drawing a design, at utmost save time cost.The making of forme tells on: improve the forme qualification rate, the printing of effectively avoiding causing because of forme is bad is scrapped in batches.

The specific embodiment

Selection-the printing graphic design of manufacture craft process original copy-forme is made before the seal.

The selection of original copy is improved one's methods: according to the characteristic of mode of printing and the characteristics of letterpress platemaking, the selection of original copy is selected to be adjusted to main pattern with the centre as far as possible, avoids light color to a high-profile, the picture of plain net, gradual change net and large tracts of land deep dark background.

Printing graphic design is improved one's methods: in photoshop, by curve curve modification calibration black and white field.Usually, the black and white field of letterpress picture and text calibration scope is between 3%-90%, and the correction of every kind of color is between 5%-10%.But this rule changes flexibly according to actual conditions, and designing a desirable picture sometimes needs to revise several times.Must be pointed out that the correction of this black and white field calibration scope and every kind of color is the universal law of letterpress, rather than changeless rule.Some original copy, for reaching certain effect, the designer loses some tint hierarchies wittingly, creates number of C MYK artificially and be 0 place, strengthens contrast, makes original copy more lucid and more lively, finally obtains best effect, reaches the effect approaching with offset printing.To handle flexibly according to actual conditions in a word.Another aspect that the picture and text design should be considered before the letterpress seal is the dot gain rate.The amplification degree of relief printing plate site very big (30%-50%), and the thickness of relief printing plate China ink layer can reach 30um, that is to say the color density height.So the site on the original copy must be revised, just can reach the purpose of true copy original copy.

The making of forme is improved one's methods: at first will guarantee the field density of negative film, use the densimeter measurement film density, require more than 4.0.Qualified density has been arranged, could correct exposure.Next requires computer (RIP) system of the laser photocomposing machine of slice to adjust, and both output density adjustment and site linearisation were adjusted.This point is extremely important, and often the someone ignores this link, and the film of result's output is inconsistent with the site percentage of the film of original copy design, finally causes forme to scrap.In the plate-making process, to find out best exposure time at last with signal strips.Effectively avoid little screen nodes loss, because original protruding seal contrast is just short, lose little site again, and picture will distortion, causes printing to be scrapped in batches.

Claims (1)

1, a kind of relief printing prepress production process improves one's methods, it is characterized in that: the selection of original copy is improved one's methods: according to the characteristic of mode of printing and the characteristics of letterpress platemaking, the selection of original copy is selected to be adjusted to main pattern with the centre, avoid light color to a high-profile, the picture of plain net, gradual change net and large tracts of land deep dark background;

Printing graphic design is improved one's methods: in photoshop, by curve curve modification calibration black and white field; Usually, the black and white field of letterpress picture and text calibration scope is between 3%-90%, and the correction of every kind of color is between 5%-10%; It is the dot gain rate that the preceding picture and text of letterpress seal design another aspect; The amplification degree of relief printing plate site is at 30%-50%, and the thickness of relief printing plate China ink layer can reach 30um, that is to say the color density height; The site of carrying out on original copy is revised, and reaches the true copy original copy;

The making of forme is improved one's methods: at first will guarantee the field density of negative film, use the densimeter measurement film density, require more than 4.0; In qualified density range correct exposure; Next requires the computer RIP system of the laser photocomposing machine of slice to adjust, and both output density adjustment and site linearisation were adjusted; In the plate-making process, to find out best exposure time at last with signal strips; Avoid little screen nodes loss.