Offset print forme is in on machine when pressworking, blank part is met sometimes on dirty, because develop is not caused thoroughly,be generally speaking, the sensitive colophony of forme blank part was not shown clean, have colophony remain.
Should make forme blank does not remain partly colophony, on one hand, want to decide light exposure according to the speed of PS edition when printing down, be like underexposure, meeting develop ungodliness falls in normal develop condition, a few colophony remain to go up in forme. On the other hand, taste to imprinting differently want distinction to treat, if high-grade and elegant colour is vivid, control of printing down time is in grey ladder feet 3 class are clean, even 2 class are clean, do not lose in order to ensure small site is basked in; And imprint newspaper edition, printing down control is in grey ladder feet 5 class are clean, show even sometimes 6, 7 class are clean, and adopt more expose to the sun by force, the pattern that shows by force, in order to shorten plate making time, ensure imprint the sex of effectiveness for a given period of time of the newspaper. Below certain condition, underexposure also can improve forme quality through aggrandizement develop, exposure crosses a head to be able to adopt the way that shows infirmly to remedy.
It is certain that at present home has this anthology pick the edition of open plan PS of 4 kinds of model makes 3 representative brands sample, with blank of edition of open plan PS the part is shown clean (without little green place) as show net level, the develop that has PS edition machines an experiment, discuss accurate develop method.
This experiment all is controlled to the exposure of PS edition in grey ladder feet 5 class are clean, be in after that microtherm 18 ℃ , normal temperature the condition of 28 ℃ issues 23 ℃ , high temperature, be opposite with PD of Hua Guang of different pH indicator developer solution respectively the edition of open plan PS of 4 kinds of model undertakes manual develop, it is the optimal develop time of this edition in order to show only time.
Edition of PS of graph of each brand this world, as a result of sensitive colophony recipe composition differs, place differs with structure of the colophony that become film, because this develop processing is endless also identical, some comfortable Yu Jiang is shown, some is comfortable show at losing. If the edition that is able to bear or endure to be shown by force is used show processing infirmly, often can show ungodliness; If be shown by force,get used to the edition that shows infirmly, often can destroy sensitive colophony layer, also dissolved the part that ought not to dissolve namely, common says edition.
(1) developer solution chroma
Developer solution chroma is develop first of 3 element, the concentration that needs to be recommended by manufacturer is made up. Usually, developer solution chroma is bigger, uses develop time is shorter, if should shorten,develop time must increase the concentration of developer solution. Of course, a lot of users are a basis actual condition determines develop condition, presswork like newspaper factory, to shorten plate making time, often adopt expose to the sun by force, the plate making condition that shows by force, developer solution chroma uses develop former liquid: Water =1: (3 ～ 4) , even 1: Of 2 deserve to compare; And high-grade colour vivid printing down, ask small site is not missing, big site has not been basked in, press exposure of condition of normal printing down commonly, grey ladder feet commands 3 stage clean, developer solution chroma uses commonly 1: (The thinner ratio of 5 ～ 6) . In addition, the chroma of developer solution must accord with the requirement of an edition that use PS.
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