CS220392B1 - Method of preparing patterns for offset print and copying on plastic foils - Google Patents

Abstract

The object of the invention is to achieve the reproduction of pen or halftone originals, including the possibility of distinguishing details and achieving line sharpness. The novel process increases, on the one hand, the transparency of the paper base of the negative or positive as a result of saturation with naphtha, paraffin oil or similar substances, and, on the other hand, the difference in the optical densities of the base and the drawing.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing offset printing and copying patterns on plastics.

At present, negative or positive printing plates are used for the preparation of offset printing plates on transparent substrates, most often by means of flat technical film capable of reproducing both spring and halftone originals in a high quality;

To create a positive or negative printing master using either autoreverzních Ilm ^{f p} ro Contact No ^b oo ^p TFC ^for Copying providing direct positive print templates or use ORK ^{p p p} Ostu negative - pos ^^ ^P ro which is characterized by double the consumption of film material than the area of a positive print original.

Print templates may be processed ^to ontaktním ^{- -} or OPTI-YM ko ^{pi observation, - - -} i.e. the dimension of the original artwork is either unchanged or is converted into a desired dimension in a photographic reproduction machine honzonWmm ^ or vertical.

Said ^{p p} ro ^py Ostu pnpravu ^Prin b ^s template according to the invention changing. The essence is that the photomechanical transfer - the image of the original to be reproduced is used in black and white positive photographic paper in both the negative and positive processes and the resulting negative or positive image is copied onto the printing plate or plastic sheet by photochemical processing. Saturating paper pads image suitable ^{plnгdlem, p} ara napnktad a new ^{fi l} ej ^on the ^F and the like, paper pads ztransparentní.

In the process according to the invention is replaced by a flat photographic film technical pa ^p Ira domestic production, of which the sensitive layer has similar sensitometric characteristics as the previously used film and the paper ^P on ^the OZ ^dl u ^l of zprůsvitntt enough. ^T hese properties are currently reflex photographic papers, document, bromo white glossy.

Because senzltomctrické sensitivity of Materials ^{ALU p} ODD ^b to S ^d NVE ^p o ^p Sanyo Шmovými materials is possible for paper negative as a photographic reproduction device, and contact copying the ^ ipads that ^{Pla dl} OHA is inmsvUne ^p o ^{d l} the ^{f ce,} but Netaji her account without rav ^{p yp} Rimo copy for the lack of difference in optical density pad and drawings.

The basic advantage of the method according to the invention lies in the high-quality results and it is possible to reproduce both spring and halftone originals with sufficient detail resolution and preservation of line sharpness, both for use - distance or contact autotypes, as well as for copopies.

Da advantage ^LSI 's ^p očív ^Å. in ^{that p} and ^p Ira ^s negative and positive after the chemical treatment can be rapidly dried in a drum or other polisher and. ' there is no need to wait for the film to dry. ; _in ^Zp USO ^bp ODTA in ^y n and ^l is a cut ^{- away} e ^- further ^- described in the following examples.

Example 1

In the photographic reproduction ..přístroji the zatož ^s noses to the ^{Pla dl h} pustasM ^- Original artwork and adjusted Dimension- 'and - - sharpness drawing an image on the focusing screen. Then - in ^the film .- azetidin ^y u ^{p f} intestinal oto ^g ra ^fi c is ^{c p} and ^p incrementally contrast-working.

After exposure, which formed in. - The susceptible VRS ^{t of} the ^p and ^p a ^b handbook tatentrn ^once, this C ^HE cally processed. Contrasting developer, break baths and fixers are used. After thorough washing, the paper negative is dried, for example in a polishing machine. Dry paper negative on its underside saturated paraffinic -okjem ^'d a te ^ peace and ^{by -} at Ravita ^{p p} r ^{i u} sv tNOS ^{Tp d} lie in its ^{alkyl world} tlých ptechách. Excess -olej is wiped cotton swab bumčhé VA of ^{the p} and 15th minutes of the RNC ^runs through the ^{p H} of the ^dl and saturated oz ^{to evenly} ... ^of oil across the surface is laterally reversed - negative ready - to. copying onto a printing plate or plastic, coated with a photosensitive negative copying layer.

Example 2

If an inverting member (prism, mirror) is attached to the lens of the photographic reproducing apparatus, the correct negative is obtained by the procedure described in Example 1 laterally. The negative created in this way results in a side inverted positive by contact copying. For further poziHvrn ^to the ^{pI o} w Eq form an ink flowed ^e p e ^{of d} Required preinstallation tasks on a printing plate or plastic is necessary to modify the translucency of the paper ^{P dl} oz ^{ky p} Ostu uvetteným ^are converted in ^{the examples} range of the first

Example 3

It is well-drawn artwork on a transparent substrate, and can not be copied on a printing plate or plastic for lack of difference in optical density pad and drawings -odstraníme this lack of contact -kopírováním contrast to pracujírn ^- pa r ^{pi. Pi} contact ^to the Eq him ^á may arise:

(a) negative, inverted

(b) negative sidewise.

P ^{p p} r rava ^the S-vitnosti jepch ^{dl p} o ^d Oz ^alkyl and the other of ^p racovárn ^p o ^p sano u ^p and ^{d at} pH ua) in ^p RU clade 1, case b) in the Example 2.

In the examples, the pattern is made on a non-transparent substrate and thus cannot be copied by the procedure of Example 3, so that a negative reversal of the negative reflective copying process is obtained. Its processing and further use is described in Example 1.

Thus, it is clear that both positive and negative copying can be used to produce an offset printing or plastic copying template.

The proposed technology is applicable to the printing industry, reproduction and planography, racing printers, special purpose printers and can be used for both monochrome and multicolor printing, regardless of size.

The dimensional deformation of the paper substrate resulting from the wet process is reduced to a negligible limit, if necessary, by wetting the photographic paper and allowing it to dry in a dark room before exposure.

Claims (2)

1. A process for preparing an offset printing and copying original for plastics, characterized in that the photomechanical transfer of the original image to be reproduced using black and white positive photographic paper in both a negative and a positive process and after photochemical processing the resulting negative or positive is copied onto printing plate or plastic film. 2. A process for preparing a printing document according to claim 1, characterized in that after the photochemical treatment, the black and white positive photographic paper is saturated with a suitable filler, for example paraffin oil, diesel, and the like.