JPH02175250A - Apparatus and method for making plate for offset press - Google Patents

Abstract

PURPOSE: To remarkably accelerate a transfer speed of a plate to a plate cylinder by delivering a meltable substance material for affecting an influence to an ink/water affinity on a point-to-point basis because of an energy action of the point-to-point basis using an electrically controlled dot delivery unit. CONSTITUTION: A transfer tape 10 is fixed to the apparatus at an upper side, movable in an intermediate space between various printing mechanism units together with the apparatus in a folded state and brought into contact with various plate cylinders at a lower side by an outward turn and suitable turn of individual sections. An image delivering unit constituted as a heatable roller 16 is advantageously combined with the lower side. When the roller 16 is brought into contact with a plate cylinder 4, the tape is press bonded to the cylinder, and substance melted by heating is delivered to a surface of the cylinder. Such delivery is conducted in a row state or a plurality of rows and hence executed remarkably faster than the delivery of the substance in the point-to- point basis to the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The invention relates to an apparatus and a method for producing plates in an offset printing press, in which a dot-like energy effect is produced using an electrically controlled dot transfer unit. The present invention relates to a type in which the printing form is transferred onto at least one printing form cylinder by means of point-wise delivery of a meltable substance material which influences the ink/water affinity accordingly.

In the device known from the prior art DE-P S 32 48 178, an electrically controlled dot transfer unit with a feeding device for the thermal transfer film is brought into direct contact with the form cylinder. Material is melted from the thermal transfer film coated with an oleophilic substance and applied to the plate cylinder by point-like energy action in response to electrical print image information. Relatively complex dot transfer units are used in each case only on one form cylinder. The preparation time for transferring a new sheet onto the plate cylinder is relatively long because the image information is transferred in a dotted manner.

Problems to be Solved by the Invention The object of the present invention is to provide a starting point which can be used satisfactorily with a dot transfer unit and which can significantly increase the speed of transfer of the plate onto the plate cylinder. To provide a method and apparatus of the type described.

Means for Solving the Problems The above-mentioned problem has not been solved by the structure of claim 1 and 14.

Effects of the Invention By interposing the transfer depth between the image point transfer unit and the plate cylinder, the time-consuming point-like transfer process in which a substance that affects the image surface of the plate is transferred to the plate cylinder. The linear or planar material transfer from the transfer tape to the plate cylinder can be carried out at extremely high speeds. '
In the configuration as a functional cassette, the transfer tape can be brought into contact with the various plate cylinders alternately.

If the length of the transfer tape is sufficient, all the print image information required in the various printing systems for shift production or day-to-day production can be easily intermediately stored on the transfer tape. The transfer of new print images to the transfer tape can take place during continuous printing. Various methods known per se are useful for transferring the material to the transfer belt and from the transfer belt to the form cylinder.

Advantageous developments of the invention are specified in the further claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a section of an offset printing press having a number of printing unit units 1, 2. Each printing mechanism unit 1, 2 consists of two printing mechanisms arranged one above the other, each of which consists of one blanket cylinder 3, one plate cylinder 4, an inking device 5, and a dampening device #6. be done.

The production of the respective plate on the plate cylinder takes place directly in the printing press. For this purpose, the following parts are provided: Above the printing mechanism units 1, 2, a rail device 7 is arranged which is supported on the side wall of the machine. is known from the crane mechanism.
The device 8 that matches is movable. The device 8 supports a pixel transfer unit 9, which is connected via signal lines to an electrical image storage (not shown). Depending on the input image signal, the image point 1 transfer unit 9 transfers the substance, which is solid at room temperature and melts under the action of energy, pointwise in a stepwise manner onto the transfer tape 10 passing through it. The transfer of the substance can take place in various ways, namely according to the thermal transfer method, in which case the underside of the transfer tape is completely coated with the substance between a dot transfer unit with a heating element and a transfer tape. Film 11 is fed out. The heating element melts the individual areas from the material layer and presses these areas onto the transfer tape 10, where the areas immediately harden by contact with the relatively cold surface of the transfer tape.

The material transfer can also be carried out according to the resistive ribbon method, in which case the dot transfer unit is provided with an electrode, which contacts the film made up of a number of layers with different electrical resistances and which has a high resistance. The electric current flowing through the layers generates the heat necessary to melt the material.

Another material transfer method for transfer tapes consists in using dot transfer units, which are equipped with heatable nozzles and work in the melt jet method and whose basic structure is similar to ink jet printers. The method consists in using a pixel transfer unit. In this case, the molten substance is either injected into the transfer tape or transferred by direct contact between the effluent material and the transfer tape.

Furthermore, the material delivery to the transfer tape can be carried out in two successive steps by forming a charge latent image on the transfer tape by means of electrometography and magnetography, and applying a toner image subsequently applied to the transfer tape. This can be done in such a way that the material is deposited more or less significantly in conjunction with the charge latent image. This is followed by intermediate fixation of the toner by heating.

In FIG. 1, the transfer tape 10 is installed in a switching robot as an endless belt that can be individually pivoted in a number of links. The link consists of a deflection roller 12, which supports the transfer tape 10 on the inside, and an elastically supported pressure roller 13, which brings the transfer tape into contact with the deflection roller. Each link is a reinforcing member 14
are connected to one another by and additionally have a drive transmission reservoir mechanism which allows separate pivoting of the individual transfer tape sections.

The measures necessary for this are technical measures known in the field of fabrication and assembly robots and are therefore not described in detail. The transfer tape 10 is fixed to the device in its upper part and can run together with the device in the folded state into the intermediate spaces between the various printing unit units and can be moved to the lower side by outward pivoting of the individual sections and appropriate pivoting. It contacts various plate cylinders at some points. An image transfer unit, preferably constructed as a heatable roller 16, is integrated in the lower part. When the roller 16 comes into contact with the plate cylinder 4, it presses the transfer tape against the plate cylinder and transfers a portion of the material which is melted by heating to the plate cylinder surface. Such a transfer takes place in a line or in a plurality of lines and is therefore much faster than transferring the material point-wise onto the transfer tape.

When the image has been transferred to the plate cylinder 4, the transfer tape 10 is
is separated from the plate cylinder. During further printing on the now image-transferred forme cylinder, the transfer tape contacts the further forme cylinder 4 and transfers the intermediately stored further printed image to the forme cylinder as a material part. The time for continued printing can also be used to transfer new printed images to the transfer belt 10 by the dot transfer unit 9. The drive for transfer tape 10 is designed with at least two different speeds in mind. That is, the intermittent slow speed is designed to deliver material in spots to the transfer tape and the continuous high speed is designed to deliver material in rows to the plate cylinder.

In the embodiment shown in FIGS. 2a, 2b and 2c, the dot transfer unit 17 is completely separated in terms of space from the offset printing press. A transfer tape 19 is provided for transferring the printed image to the plate cylinder 18 in the form of particles of a substance that influences the ink/water affinity, which transfer tape is fixedly incorporated in the cassette 30 and is located within the cassette. It is arbitrarily wound up and unwound between two reels.

The pixel transfer unit 17 is configured as a thermal transfer device similar to the pixel transfer unit 9 of the first embodiment.
It is also possible to use other devices as described in the first embodiment for the pixel transfer unit. A thermoprinthead 20 with at least one pin electrode or heating element is movable along a guide 21 arranged transversely to the running direction of the transfer tape 19. The movement of the printhead and the energy loading on the electrodes/heating elements are controlled by a control unit 22 which is connected via signal conductors 23 to an electrical or opto-electrical image memory (not shown). There is. Between the electrodes/heating elements of the 7° lint head 20 and the transfer tape 19 is located a film 24 with a layer of material on its underside.

The heating element dissolves individual areas from the substance j- by melting when heated in a manner controlled according to the print image information. This area is applied to the surface of the transfer tape 19 and immediately hardens again on the cold surface of the transfer belt. If the material parts are transferred for one row or, if multiple heating elements are used, for multiple rows, the transfer belt 19
is moved by the appropriate number of rows and the next row is passed.

The transfer tape 19 is preferably made of two layers, namely a base layer and a material part that is extremely strong against the tensile forces rc for the desired registration in the longitudinal direction, has non-stick properties and is heat resistant. It consists of a cover layer. For the cover layer, for example polytetrafluoroethylene (PTF
E) is particularly suitable. Transfer tee 7019 has some degree of compressibility in its thickness to compensate for linear variations in transferring material to the plate cylinder with a suitable compression force.

The length of the transfer stacker '19 used in the cassette 30 is designed to allow intermediate storage of a large number of printed images (e.g. all the printed images required for a shift production or -day production) in the transfer stacker '19. It's been done. However, it is also possible to record only one printed image out of seven, and to record this printed image on plate 1.
During the transfer to 114 the image can already be transferred to another cassette.

The cassette 30 to which the image has been delivered is transferred to the image point delivery unit 17
It is then conveyed away from the printing form +110118 (see FIG. 2b) onto which the image is to be transferred and is pulled out of contact with this printing form cylinder.

A series of solutions are available for transporting and mounting the cassettes, which are not important to the invention and will only be described in broad strokes.

The cassettes are held by grippers in a conveying device mounted, for example, on the printing press frame or on the factory ceiling, and
8 and is latched in a receiving device installed there. In this case, a driving connection is advantageously provided between the transmission element that drives the form cylinder and the transmission element that drives at least one of the reels of the cassette.

This is because, in the case of material transfer, the plate cylinder and transfer chip must move at synchronous speeds.

The material part is transferred to the form cylinder 18 by applying a thermal effect to the back side of the transfer tape 19 using the image transfer unit 25 . Thermal action is assisted by pressing a transfer tape 19 onto the plate cylinder 18. In the case of suitable ferromagnetic material transfer or material transfer using charged or polarized particles, the transfer to the plate cylinder can be assisted magnetically or electrostatically.

For this purpose, a pair of magnets 26 are arranged inside the plate cylinder 18 and on the back side of the transfer tape 19. Instead of magnets 26, electrodes can be placed on the back side of transfer tape 19. The electrode and the plate cylinder are energized so that an electric field is created that aids material transfer. Image delivery unit 2
5 is preferably formed by a heatable transfer drum 29, which contacts the rear side of the transfer tape 19 after the cassette 30 has been hooked up in front of the plate cylinder (second c.
(see figure). In a further variant, not shown, an image transfer unit is integrated into each cassette and is simultaneously connected to the energy source when the cassette is latched in front of the form cylinder.

According to the invention, in order to erase the image transferred to the plate cylinder, after washing away the residual ink, the plate cylinder is heated internally or externally to liquefy the material and the plate cylinder surface is heated by a suitable doctor and cleaning device. remove from

In a preferred embodiment, the surface of the plate cylinder is provided with a consistent hydrophilic coating and the ink-guiding image areas are each formed by applying a thermoplastic, oleophilic zolantic.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIG. 1 shows an apparatus having a transfer tape configured as a moving transfer that can contact various plate cylinders. 1.2...Printing mechanism unit, 3...Blank cylinder, 4゜18...Plate cylinder, 5...Inking device, 6...Moistening device, 7...Rail device, 8...・Device, 9, 17...
Image point delivery L unit, 10.19...Transfer tape, 1
1゜24...Film, 12...Deflection roller, 13...
- Pressure roller, 14..., reinforcing member, 16... roller, 20... print head, 21... guide, 22
...Control unit, 23...Signal conductor, 25...
Image transfer unit, 26...Magnet, 30-...Cassette FIG, 2Q FIG, 2b

Claims (1)

[Claims] 1. An apparatus for producing a plate in an offset printing press, which affects ink/water affinity in response to a dot-like energy action using an electrically controlled dot transfer unit. of the type in which the printing form is transferred onto at least one printing form cylinder by a dot-like delivery of meltable substance material, in which a dot transfer unit (9, 17) and a printing form cylinder (4) are used.
, 18), a transfer tape (10, 19) is arranged on which transfer tape (10, 19) is provided with an image-wise material transfer by means of a dot transfer unit, and is arranged between one or more plates. An image transfer unit (1) is attached to the cylinder (4, 18).
6, 25) are contactable, and this image transfer unit transfers the plate cylinder or plate cylinders from the transfer tape (10, 19) by linear or areal energy action on the transfer tape (10, 19). (4, 18) A device for producing a plate in an offset printing press, characterized in that it is adapted to deliver a substance to (4, 18). 2. The transfer tape (10) and/or the image transfer unit (16, 25) are pivotable and/or movable at least in a plane perpendicular to the axis of the plate cylinder (4, 18). The device described. 3. Device according to claim 1 or 2, characterized in that the transfer tape (10) is designed as an entresive tape. 4. The dot transfer unit (17) is completely separated from the plate cylinder (18) in terms of space and the transfer tape (19)
) is arranged in an exchangeable cassette (30),
Apparatus according to any one of claims 1 to 3. 5. The image dot transfer unit (9, 17) is configured as a thermal transfer printing unit equipped with a heating head, and the film (11) covered on the side of the transfer tape can be fed out between the heating head and the transfer tape. 5. The device according to claim 1, wherein the device is arranged such that: 6. a pixel transfer unit (9) which first forms an image-wise charged latent image on the transfer tape according to an electrophotographic, electrographic or magnetographic method;
, 17) to transfer the image to the transfer tape (10, 19), said charged latent image forming an image forming a plate via a toner-like substance in a connected application device. 5. The device according to claim 1, wherein the device is configured as follows. 7. The dot transfer unit (9, 17) is constituted by a unit having a structure similar to an ink jet printer, which jets the substance onto the transfer tape (10, 19) according to the melt jet method. , any one of claims 1 to 4
The device described. 8. At least one layer of the transfer tape (10, 19) carrying the material part is made of polytetrafluoroethylene (PT).
8. The device 9 according to claim 1, wherein at least one layer of the transfer tape (10, 19) consists of a material that is compressible in terms of thickness. Apparatus according to any one of claims 1 to 8. 10. Device according to one of the preceding claims, characterized in that the image transfer unit (16, 25) consists of a heatable roller. 11. Device according to claim 10, characterized in that the rollers (16, 25) are mounted in such a way that they press the transfer tape (10, 19) onto the plate cylinder (4, 18). 12. A pair of stationary magnets or electrodes (26) are provided on the back side of the transfer tape (19) near the roller (16) and inside the plate cylinder (18), the magnets or electrodes being ferromagnetic. in the case of substances to be delivered by means of electrostatically charged or polarized particles, adapted to magnetically or electrostatically assist the delivery of the substance to the plate cylinder; Apparatus according to any one of claims 10 to 11. 13. The device according to claim 1, wherein the plate cylinder (4, 18) has a seamless ceramic surface. 14. A method for producing plates in an offset printing press, comprising a meltable substance material which influences the ink/water affinity in response to a dot-like energy action using an electrically controlled dot transfer unit. In the type of printing plate that is transferred to at least one plate cylinder by passing the printing image in the form of dots, a) the electrically stored printed image is read out from the memory device in the form of dots, and the dots are (b) transfer by means of the pixel transfer unit in which the substance is passed in a stepwise manner along the pixel transfer unit in a dot-like manner by the action of energy in accordance with the printed image; tape(
10, 19), C) Transfer tape (10, 19)
Transfer tape (10, 1
9) is guided through an image transfer unit (16, 25) which contacts the various plate cylinders (4, 18) alternately; d) is transferred by the image transfer unit (16, 25) under the action of energy A method for producing plates in an offset printing press, characterized in that the material applied to the tape (10, 19) is transferred in rows or planes to the plate cylinder (4, 18). 5. Remove the image transfer unit (16, 25) and the transfer tape from the plate cylinder (4, 18) after complete transfer of the plate and transfer another printed image to another plate while continuous printing is being carried out. Transfer to the barrel or transfer tape to the image transfer unit (
15. The method according to claim 14, wherein the image is delivered anew by 9, 17). 6. To erase the plate on the plate cylinder, after printing is finished, the plate on the plate cylinder is erased by heating or chemically melting and then mechanically removing the residual material and preparing it for receiving a new plate. The method according to claim 14 or 15.