DE1206917B - Process for writing on lithographic printing plates - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4Ä PATENT OFFICE Int. α .:

B 41 c

EDITORIAL

German K] 15 b -1/05

Number: 1206 917

File number: C26180VIb / 15b

Filing date: February 7, 1962

Opening day: December 16, 1965

The invention relates to a new method for inscribing planographic printing plates using new donation sheets.

Lithographic planographic printing plates are usually made under pressure, e.g. B. by tapping or Writing, inscribed on its hydrophilic surface with an imaging, oleophilic composition. The plate labeled in this way is then colored with an oily, conventional lithographic ink, this color adheres to the oleophilic image areas, but from the unmarked, hydrophilic ones Place the plate is repelled. Such a system allows the manufacture of numerous Prints or copies.

It has been shown that in many cases the manual application of the oleophilic image to the surface the printing plate is inconvenient or impossible, e.g. B. if the printing plate is too wide to be in a Typewriter to fit, or consists of a rotating roller, as z. B. for sample printing and the like is used.

Also arise with the manual labeling of plates, z. B. by typing or tapping on it, very often errors which either have to be erased or why the plate was discarded and a new must be started. Although in most cases the surface of the plate is strong enough to Withstand erasing, care must be taken to ensure that the hydrophilic surface coating is not removed or damaged, otherwise the plate will become unusable.

Another disadvantage of the manual inscription of lithographic plates is based on the fact that the Plate surface is hydrophilic and oleophobic and therefore repel the oleophilic images adhering to it tries. If when writing or typing these images on the plate surface therefore not If the work is done carefully, the images can easily rub off during the making of copies or removed.

The object of the invention is therefore the inscription of lithographic plates without affecting the Surface of the plate an imaging pressure needs to be exerted.

According to the invention, one inscribes a donor sheet which is permeable to infrared radiation with a heat-fusible, infrared radiation absorbing, oleophilic, image-forming material, a lithographic plate is placed on the written surface of the donor sheet in contact with it, and the donor sheet is exposed to infrared radiation until the image areas have melted and to methods for marking lithographic
Printing plates

Applicant:

Columbia Ribbon and

Carbon Manufacturing Co., Inc.,

Glen Cove, Long Island, N.Y. (V. St. A.)

Representative:

Dipl.-Ing. E. Prince and Dr. rer. nat. G. Hauser,

Patent attorneys,

Munich-Pasing, Ernsbergerstr. 19th

Named as inventor:

Douglas Alexander Newman,

Glen Cove, Long Island, N.Y. (V. St. A.)

Claimed priority:

V. St. v. America February 13, 1961 (88 745)

adhere to the working surface of the plate, and then separates the plate and the donor sheet from each other with at least partial transfer of the material d: image areas on the plate.

It is the heat transfer of a pattern for the production of stencils, hectographic printing plates or planographic printing forms known. For the production of planographic printing forms, it is based on A transfer sheet is placed on the plate, which does not have a layer of oleophilic, infrared radiation absorbing composition, and on this sheet in turn an infrared radiation absorbing Original sheet bearing the image. Absorb the image areas on the original sheet with infrared radiation the radiation and convert it into heat, which causes the image areas corresponding points in the heat transferable layer are melted and onto the plate surface flow where they result in oleophilic image areas.

The main advantage of the method according to the invention over the known method consists in that upon infrared irradiation of the translucent sheet carrying the original image areas these original image areas become soft and sticky and with the result that they are sharply outlined and more faithful to the original Imprints of the original image areas adhere to the planographic printing plate, while in the known Process the oleophilic, heat transferable material must melt and then onto the plate surface flows so that the image areas obtained thereon

509 758/26

3 4

will be slightly widened and imprecise, especially since the image sections are never on the donor sheet

can be completely avoided that applied in the environment by placing the sheet 10 in surface

the image areas, d. H. at their edges, the thermal contact with the transfer printing layer 21 on the

transferable layer of the transfer sheet further brings transfer sheet 20 and either on the Boals is intended to be soft and partially with over- 5 over 10 or on the arch 20, depending on the shape of the

goes. desired image, an image-forming print

Another advantage exercised by the practice of the invention. If a typewriter is used for this

driving consists in the fact that the on the surface of the, one expediently removed the ribbon, so

Planographic printing plate formed, oleophilic image areas that the typewriter types either directly with Absorb infrared radiation and heat around the sheet 10 or with the sheet 20 in contact

you can, so that such plates also come thermographic and thus produce sharper image areas,

can be phically reproduced. This applies to when this would be possible in the presence of the band,

the known plates do not, since that to their Her- The composition of the transfer printing layer 21 form-

Position used, oleophilic material no infra- det an essential feature of the invention, since the may contain substances that absorb red radiation. 15 this layer-forming mass in the form of image

Furthermore, the threading 30 a according to the invention, which take up the color, move onto the plate, is of course much more economical than the known method, since the copy sheet or sheets are transferred to. In order to produce each individual planographic printing form, not a printing layer, an oleophilic, transferable transfer sheet must be used every time a transfer sheet is used. Contain composition which has an affinity for the Rather, according to the invention with an ao conventional oily lithographic printing inks. The composition must also be able to see infrared radiation, absorb original translucent sheets repeatedly and convert it into heat. In addition, it must have a melting point between about 38 to produce several planographic printing plates. The lettering can be, for. B. in and 121 ° C, as this temperature range is done on a typewriter. 25 generated by the usual infrared radiation devices

The invention is illustrated by the following description.

Exercise in connection with the drawing. It has also proven to be useful that

tert. In the drawing, the mass forming the transfer printing layer does not show any

Fig. 1 has a perspective view of a sharp melting point, so that therefrom

written original or donor sheet 10 together- 30 generated image areas 11 over a temperature

Men with a transfer sheet 20 that melts an area of several degrees. To this

Transfer layer 21 carries, with which the sheet way, the image areas are only soft and adhere

10 was inscribed, sharp on the surface of the plate, and the complete

Fig. 2 is a schematic cross-sectional view in melting of the image areas takes place slowly. Will be a enlarged scale of the inscribed original 35 transfer printing material with a sharp melting point or donor sheet 10 is used with a lithographic one, the image areas 11 suddenly become Plate 30, the two being liquefied for the sake of clarity and having a tendency to separate on the plate and spread out below the surface to be interwoven, so that indistinct lithocations are produced from infrared radiation, receives graphic copies. Excellent results

Fig. 3 shows the sheets of Fig. 2 after irradiation, 40 obtained in this regard when the transfer printing was the image areas 30 a of the sheet 10 on the mass a mixture of different binders, entOberfläche The lithographic plate does not transfer waxes or thermoplastic resins or became. preferably mixtures of the same with different

The objects of the invention are how the melting points together with an infrared drawing shows, through the use of an origi- 45 radiation absorbing pigment, z. B. nigrosine Nal- or Donatorbogens 10 met, the surface and / or carbon black contains.

borrowed image areas 11 from an oleophilic mass, the following examples show transfer printing masses, absorbs the infrared radiation and converts it into heat, which is converted in the method according to the invention and a melting point between about 38 will provide plotted results. However, it is and 121 ° C. 50 notes that these masses are for illustrative purposes only

These image areas 11 can either be used directly and the invention is not restricted thereto.

legible positive lettering or a reversed example 1

Be mirror image lettering, depending on the type of ^p

Printing process for which the finished lithographic components are parts by weight

phical plate should be used. 55 carnauba wax 45

The original or donor sheet 10 can be removed from the beeswax 5

neither from paper nor from a clear plastic- Polymerized butene isomers 15

film, e.g. B. cellophane or mylar; on every nigrosine 20

In this case, it must be relatively translucent, such as mineral oil 20

that infrared radiation to the image areas 11 is at 60. .

can penetrate the underside. The translucent example

The nature of the donor sheet gives the other constituents parts by weight

Ren advantage that the lettering on its lower part

side in the form of the paraffin 5 denoted by 12 in FIG. 1

Image areas becomes visible and through the top, 65 polyisobutylene 10

d. H. the unlabeled side, can be checked. Nigrosine 15

This is particularly important when the label is soot 10

device 11 is a mirror image, as shown in FIG. 1 shows. Rapeseed oil 20

Claims (1)

5 6 Example 3 The type of infrared radiation source used Components parts by weight jf * ^{not k} ? ^US ? ^h > ^eS ^ Pf ^ P ^ P ^ ' ^coal " bent and photographic flashlights under Microcrystalline Wax 15 used producing excellent results Carnauba wax 20 5. A conventional one is preferably used Chlorinated rubber 20 Flat form or belt conveyor, e.g. Legs Nigrosin 25 thermofax machine. Irradiation of the arches ermineral oil 15 only follows until the image areas 11 have melted Lanolin 5 are, depending on the proximity and strength of the 10 source either immediately or within about Which is the case with one of the above compositions for 5 to 10 seconds. labeled, translucent donor sheets. The invention can be varied widely is first experienced with a suitable, customary, lithographic technique, without leaving its scope graphic printing plate 30 collapsed so that,
the image areas 11 with the hydrophilic surface 15 surface of the plate are in surface contact. Patent claims:
The sheets are then exposed to a light source 50 rich in infrared radiation directed at the donor lithographic sheet 1. Method of Writing, as shown in FIG. 2 shows printing plates irradiated with an oleophilic image generator for so long that the image areas 11 melt and adhere to the material characterized on the plate surface. After removing the sheet from the area of the radiation source that is permeable to infrared radiation, parts of the image areas 11 are heat-fusible, infrared radiation absorbed from the plate surface in the form of oleophilic, oleophilic, image-generating sheets Adjust material 30 α has been recorded, as can be seen in FIG. 3 25, which points to the image-forming material; On the donor sheet, remnants of the image-written surface of the donor sheet have remained in positions 11a which, for writing contact with it, places a lithographic plate of further lithographic plates on the same way that donor sheet can be used with infrared radiation. If necessary, long exposure until the image areas have melted, the used donor sheet can also be kept as a lead file and stick to the work surface of the plate. and then the plate and donor sheet from- The inscribed lithographic plate can separate for one another. Usual lithographic copying processes for the production of 2. Process for the writing of lithographic supply of three hundred to four hundred sharp printing plates according to claim 1, characterized in trains are used. 35 records that the imaging material is over The type of the process according to the invention has a wide temperature range of several Ren used lithographic plate 30 is not degrees Celsius melts. significant; Usual plates with hydrophilic 3. A method for inscribing lithographic surfaces on the basis of carboxymethylcellu- printing plates according to claim 2, characterized in that sodium alginate, polyvinyl alcohol, gelatin, 40 distinguishes that the image-forming material can be seen in the manner described melts around 38 and 121 ° C,
with good results. 4. A method for labeling lithographic It has been shown that the use of printing plates according to one of the preceding infrared radiation is an essential feature of the He- claims, characterized in that the invention represents, since it is the selective heating of the 45 image-forming material a mixture of different Image areas on the donor sheet without substantial dener wax binder with different heating of the donor sheet itself and the litho-melting temperatures,
graphic printing plate allows. The heated 5th method for inscribing lithographic image areas go sharp and clean on the plate printing plates according to one of the preceding surfaces, which in printing and copying 50 claims, characterized in that the drive in which the quality of hundreds of image-generating Material, a mixture of copies produced from the plate ultimately depends on the quality of the wax and a thermoplastic resin binder of the lithographic image on the plate with different melting temperatures. It was found holds. that when using heat instead of infrared 55 6. Process for marking lithographic red radiation for the transfer of the donor sheets and printing plates according to one of the preceding the lithographic plate can also be heated, so claims, characterized in that the that the image areas 11 on the warm or hot oleophilic, image-forming material in a Donor sheets melt and dissolve and therefore put a transfer layer on a transfer sheet Lose sharpness; on the tub or hot 60 takes place and imagewise by pressing on a surface The donor sheet is transferred to the lithographic plate. then even further, so that one is on the finished plate blurry images and very poor lithographic fonts considered: receives phical copies. German publication No. 1019 320. 1 sheet of drawings 509 758/26 12.65 © Bundesdruckerei Berlin