EP2269834A1 - Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression - Google Patents

Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression Download PDF

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Publication number
EP2269834A1
EP2269834A1 EP09164137A EP09164137A EP2269834A1 EP 2269834 A1 EP2269834 A1 EP 2269834A1 EP 09164137 A EP09164137 A EP 09164137A EP 09164137 A EP09164137 A EP 09164137A EP 2269834 A1 EP2269834 A1 EP 2269834A1
Authority
EP
European Patent Office
Prior art keywords
image
printing
resolution
pixel
printing plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09164137A
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German (de)
English (en)
Inventor
Matthias Dr. Riepenhoff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wifag Maschinenfabrik AG
Original Assignee
Wifag Maschinenfabrik AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wifag Maschinenfabrik AG filed Critical Wifag Maschinenfabrik AG
Priority to EP09164137A priority Critical patent/EP2269834A1/fr
Publication of EP2269834A1 publication Critical patent/EP2269834A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/006—Cleaning, washing, rinsing or reclaiming of printing formes other than intaglio formes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41P—INDEXING SCHEME RELATING TO PRINTING, LINING MACHINES, TYPEWRITERS, AND TO STAMPS
    • B41P2227/00—Mounting or handling printing plates; Forming printing surfaces in situ
    • B41P2227/70—Forming the printing surface directly on the form cylinder

Definitions

  • the present invention relates to a method for changing the printed image on a printing form and to an apparatus for carrying out the method.
  • the invention relates to the field of reusable printing plates, such as planographic printing plates, in particular offset printing plates, in particular wet offset printing plates and in particular wet offset printing forms for newsprint printing.
  • a printing plate In offset printing, a printing plate is used which has ink-conducting and ink-repellent surfaces.
  • the ink-bearing areas are the image areas
  • the color-rejecting areas are the non-image areas.
  • non-image sites are hydrophilic
  • image sites are lipophilic.
  • Wet offset printing is the predominant process for newspaper printing.
  • CTP computer-to-plate
  • Imaging methods are referred to as Computer to Press (CTPress) or - in the case of a laser exposure in the printing unit - as direct imaging.
  • Potential benefits can be realized by reducing the cost of the devices, reducing changeover times, and requiring a large number of die changes due to the variety of print jobs.
  • the printing plate in wet offset is in most cases a known per se aluminum printing plate, which is mounted on a support cylinder.
  • the printing plate is imagewise exposed outside the printing machine and chemically developed so that it carries the desired image information. After printing, the pressure plate is changed.
  • process-free printing plates which are provided outside the printing unit or in the printing unit by means of laser radiation with a latent image which appears in the course of the printing process due to the contact with the liquids used during printing (printing ink and dampening solution), without a additional process step, such as, for example, a chemical development, is needed.
  • a process-free printing plate the printing plate must be changed after production. Manufacturing and changing of printing plates is usually associated with high labor and cost.
  • a liquid may be sprayed on an aluminum printing plate.
  • the liquid is dried and in this way creates a printing plate, which can be imaged like a process-free printing plate.
  • the plate is cleaned to prepare for the next printed item.
  • It can be prepared by spraying a liquid and further process steps in a separate device for printing a metal sleeve used as a printing forme.
  • the sleeve can be used multiple times, but must always be removed and reinstalled to change the printed image.
  • a steel cylinder can be used as a printing plate, on the surface of which structures can be applied or removed imagewise by means of a series of chemical, physical or mechanical processes, which are suitable for wet offset printing. These are reusable printing plates. Although the labor required for the change of the printed image is reduced, however, the erasure and re-imaging of the printing plate cylinder requires much time during which the printing press can not print.
  • the EP 1 837 175 A1 discloses a printing plate which contains in a layer a plurality of surface elements formed as electrodes, which influences the surface characteristic of a dielectric functional layer upon application of an electrical voltage.
  • EP 1 020 304 A2 discloses a method in which areas of a printing plate are switched by thermal processes between hydrophilic and hydrophobic behavior.
  • This printing form carries a first printed image A. It is desired to replace the existing first printed image A with a new, second printed image B.
  • the spatial distribution of the image and non-image areas of the first print image A and the second print image B is represented by two 2-dimensional matrices A, B of binary elements.
  • a matrix has the logical value 1 if there is an image location at the corresponding location of the printing form, or 0 if there is a non-image location.
  • TIFF image data
  • BMP PNG
  • RAW Raster Image Writer
  • JPG JPG
  • it may be a data format that does not use any methods of compressing the data set.
  • the image data may also be in compressed form, eg as TIFF / G4 data. Preferred are so-called lossless data formats.
  • the matrix C represents all picture elements (pixels) which have the same value in both matrices A and B. It corresponds to the areas whose surface property does not need to be changed, i. a color-guiding picture element remains color-guiding, a non-picture-point remains a non-picture-point.
  • add or remove are preferably to be understood to mean that image sites are added (for example by adding or removing material) or removed (for example by removing or adding material).
  • the removal process is applied to the pixels contained in the matrix D.
  • the adding process is applied to the picture elements contained in the matrix E.
  • Both pictorial processes refer neither to the first, original print image A, nor to the second, new print image B, but to two auxiliary images D and E to be calculated in each case.
  • Both imagewise processes are based on image data, which are preferably present with the same resolution.
  • image data which are preferably present with the same resolution.
  • image data In contrast to the erasure of an image known from the prior art by processing or influencing the entire surface of a printing form, only the (pixel-by-pixel) removal of the actual image areas that do not occur in the new image is necessary.
  • Imaging of a printed image In contrast to the well-known Imaging of a printed image is only the (pixelwise) adding the new image in the old image not yet available required. Thus, the effort to change the print image is minimized while reducing the time to change the print image.
  • image data of the new and the old print image are not available with the same resolution, it is possible to convert this data so that both print images have the same resolution.
  • Corresponding methods for changing the image resolution are known and implemented in programs that are used in the graphics industry, for example in the software "Photoshop” by the manufacturer Adobe, so that their description is omitted.
  • An addition process may be a process by which, for example, at least one image location or pixel is reformed by adding material, for example, color-friendly material, for example on a printing plate or printing plate.
  • an image location can be created, for example, by removing or ablating a non-image location of, for example, non-color-friendly material.
  • under the non-image forming color-repellent surface structure or layer of the printing form may be present, for example color-friendly material or a layer, with which or which an image location or pixels can be formed.
  • a removal process may be a process involving, for example, at least one image location or pixel by adding material, for example, ink-repellent material, for example, on a printing form or pressure plate, is removed.
  • an image location can be created, for example, by removing or removing an image location from, for example, color-friendly material.
  • a material or a layer may be present with which a non-image site can be formed.
  • a laser irradiation process can be used both as an add process and as a removal process.
  • a non-image site When a non-image site is converted into an image site by the action of laser radiation, it is an adding process (an image site). This may be the case, for example, when a printing form has a color-friendly, for example, hydrophobic surface which, at the non-image sites, has a color-repelling, e.g. having hydrophilic material. If, at one point, the dye-repellent material is desorbed by the action of laser radiation, an image site is formed there. In this case, the laser process acts as an add process, removing material.
  • an image site is converted into a non-image site by the action of laser radiation, this is a removal process.
  • This may be the case, for example, if a printing plate has an ink-repellent, for example, hydrophilic surface which has an ink-accepting material at the image locations. If, at one point, the dye-absorbing material is desorbed by the action of laser radiation, a non-image area is formed there. In this case, the laser process acts as a removal process.
  • An inkjet process can be used both as an adding process and as a removal process.
  • a non-image point is converted into an image point by an inkjet process, it is an addition process. This may be the case, for example, when a printing plate has an ink-repellent, for example, hydrophilic surface. If ink-accepting material is applied at one point by an inkjet process, an image location is created there. In this case, the inkjet process acts as an adding process.
  • an image point is converted into a non-image point by an inkjet process, it is a removal process. This may be the case, for example, if a printing plate has an ink-accepting surface. If ink-repellent, for example, hydrophilic material is applied at one point by an inkjet process, a non-image area is formed there. In this case, the inkjet process acts as a removal process.
  • the imaging of the printing form (s) or printing plates can also be done, for example, photomechanically with a subsequent development, for example by imagewise or pixelwise exposing and then solidifying (positive copy) an image location or a non-image site, such as a silicone layer, or by pixelwise or imagewise peeling (negative copy).
  • a spark erosion process or a thermal removal for example via laser beams, in particular IR laser, are performed.
  • the image-wise, for example, pixel-wise or independently, for example, temporally sequentially acting on individual image locations processes place high demands on the corresponding devices with regard to the register accuracy.
  • the devices should be able to be positioned to add and remove image locations with high accuracy to the, for example, curved or even flat printing form to act on the respective image locations.
  • the advantages of the method according to the invention are particularly useful when it is applied in the printing unit of a printing press, since the or all printing plates and the devices according to the invention can be permanently mounted and their relative position to each other remains unchanged.
  • the implementation of the method within a printing unit is therefore a particularly preferred embodiment.
  • the Entfemungs- and / or adding devices may be flat, linear or point (pixel) shaped provided.
  • the printing plate can be reimaged with a single drive past.
  • each image changing point may be formed of a pair of a material adding device, for example, an ink jet printing nozzle, and a material removing device, for example, a bearing member.
  • Both the material adding device and the material removing device may be punctiform, linear or planar, wherein, for example, a punctiform material removing device or material adding device may be combined with a linear or sheet-like material adding device or material removing device.
  • a linear-acting material removal device or material adding device can be combined with a surface-acting material adding device or material removal device.
  • a surface-acting material removal device or material processing device should be understood to mean a device which can act, for example, two-dimensionally pixel-by-pixel, ie image element by image element independently of one another, on a surface, for example a printing plate.
  • the imagewise processes may optionally be combined with non-image-wise, for example, surface-area and not pixel-wise processes on a printing plate, without violating the pictorial character in the sense of the invention. This is especially the case when in the non-imagewise process there is no material transfer to the printing form or away from the printing plate.
  • an image-wise application of a liquid by means of inkjet with subsequent surface hardening of the liquid for example by means of UV radiation or thermal radiation, is an overall image-wise process.
  • the removal process is performed with a laser.
  • this is to be generated by a laser light source Radiation minimized.
  • the removal process can be, for example, a desorption process in which material located on the printing form is thermally released from the surface. It may be a process in which the material to be removed is decomposed, leaving only gaseous residues, for example. Because the total amount of material to be removed is minimal, special measures can be dispensed with in many cases to remove residues (for example, suction devices, brush systems, cleaning cloths, rinsing devices). But it is also possible to take such measures if necessary.
  • the adding process is carried out by an inkjet method. Because only the difference image has to be formed anew with respect to the print image to be changed, the amount of material is minimized.
  • the imaging material may be a liquid in which molecules are dissolved that adsorb to the surface. Because the total amount of liquid applied is small, any solvent used can evaporate quickly. Because of the small amount can be dispensed with measures for the extraction of the solvent in many cases. But it is also possible to provide a suction.
  • the imaging material can be, for example, a hydrophilic or hydrophobic liquid which is cured by UV radiation or thermal radiation and is thereby bound to the surface of the printing plate.
  • a corresponding irradiation can take place imagewise with the same resolution of the addition process. However, irradiation can also take place with reduced resolution or concern the entire area or parts of the area.
  • the printing plate is cleaned over the entire surface before the process of changing the printed image.
  • residues of printing ink which are due to a previously made print production on the image locations of the printing form, removed.
  • This can be supported for example by spraying cleaning agents. It is also possible to achieve a cleaning of the printing form by the ink supply is interrupted, and the ink residues on the blanket are transferred to the paper.
  • the method according to the invention can preferably be used in cases in which a distribution of material on the printing form characterizes the printed image.
  • the method is used in the printing unit of a printing press, preferably for imaging several or all printing forms, for example simultaneously or successively.
  • the inventive method has improvements over the prior art.
  • the materials used are used very sparingly. It is usually not necessary to remove excess imagery through a separate process step. No previous or previous process steps are required to completely delete a picture. The energy required to change a print image is reduced. A disposal of cleaning residues is usually not necessary. The time required to change the printed image is less in the inventive method than in the prior art.
  • An apparatus comprises a removal and addition system, such as a laser imaging system and / or an inkjet imaging system. Furthermore, the device comprises means for reproducibly adjusting the position of the printing form, or of the printing forme cylinder, relative to the imaging systems. These include actuators, such as linear motors or stepper motors, and sensors, such as linear encoders or rotary encoders, for controlling linear movements or rotational movements of the printing plate and / or the removal and / or adding system. Furthermore, the device according to the invention comprises means for storing image data, processing and transferring them to the imaging systems and for synchronizing the imagewise action of the imaging systems with the relative movement between the printing form cylinder and the imaging system.
  • FIG. 1a a first printed image A is present on a printing form, wherein the FIG. 1a ) can also be regarded as a two-dimensional matrix A, wherein the locations of the printing form on which an image location is provided and which are represented in the matrix by the logical value 1, for example, are shown in black.
  • the non-image areas of the printing form or the elements of the matrix, which represent non-image areas and consequently carry a different value than those elements which represent an image location are shown in white (logical O in the matrix).
  • FIG. 1b shows a second printed image B, or a corresponding representation of a die, wherein the second printed image B, the in FIG. 1a ) should replace first printed image A shown.
  • a matrix C can be calculated in accordance with the above formula, wherein the matrix C represents all pixels or pixels which have the same value in both printed images or matrices A and B and thus do not have to be changed.
  • the not to be changed image locations in Figure 1c whereas changes must be made in the area of the white pixels shown.

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  • Manufacture Or Reproduction Of Printing Formes (AREA)
EP09164137A 2009-06-30 2009-06-30 Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression Withdrawn EP2269834A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP09164137A EP2269834A1 (fr) 2009-06-30 2009-06-30 Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP09164137A EP2269834A1 (fr) 2009-06-30 2009-06-30 Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression

Publications (1)

Publication Number Publication Date
EP2269834A1 true EP2269834A1 (fr) 2011-01-05

Family

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Application Number Title Priority Date Filing Date
EP09164137A Withdrawn EP2269834A1 (fr) 2009-06-30 2009-06-30 Procédé et dispositif de modification d'une image d'impression sur une plaque d'impression

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EP (1) EP2269834A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965444A1 (fr) * 1998-06-17 1999-12-22 Scitex Corporation Ltd. Système et méthode pour l'impression lithographique utilisant des supports à surface réutilisable
EP1020304A2 (fr) 1999-01-18 2000-07-19 Fuji Photo Film Co., Ltd. Procédé d'impression lithographique et imprimante l'utilisant
WO2000058095A1 (fr) 1999-03-29 2000-10-05 Kodak Polychrome Graphics Company Ltd. Plaque planographique pour impression directe et son procede de preparation
DE10024184A1 (de) 2000-05-15 2001-11-22 Koenig & Bauer Ag Verfahren zum Behandeln von erneut bebilderbaren Druckformen oder Druckformzylindern in Druckmaschinen
DE102005048983A1 (de) * 2005-10-13 2007-04-19 Man Roland Druckmaschinen Ag Verfahren zum Bebildern von Druckformen
EP1837175A1 (fr) 2006-03-22 2007-09-26 MAN Roland Druckmaschinen AG Plaque d'impression et unité d'impression d'une presse
JP2008046447A (ja) * 2006-08-18 2008-02-28 Toray Ind Inc 印刷版の製造方法
EP1769909B1 (fr) 2005-09-28 2008-06-11 MAN Roland Druckmaschinen AG Méthode pour former des images sur plaques d'impression

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0965444A1 (fr) * 1998-06-17 1999-12-22 Scitex Corporation Ltd. Système et méthode pour l'impression lithographique utilisant des supports à surface réutilisable
EP1020304A2 (fr) 1999-01-18 2000-07-19 Fuji Photo Film Co., Ltd. Procédé d'impression lithographique et imprimante l'utilisant
WO2000058095A1 (fr) 1999-03-29 2000-10-05 Kodak Polychrome Graphics Company Ltd. Plaque planographique pour impression directe et son procede de preparation
DE10024184A1 (de) 2000-05-15 2001-11-22 Koenig & Bauer Ag Verfahren zum Behandeln von erneut bebilderbaren Druckformen oder Druckformzylindern in Druckmaschinen
EP1769909B1 (fr) 2005-09-28 2008-06-11 MAN Roland Druckmaschinen AG Méthode pour former des images sur plaques d'impression
DE102005048983A1 (de) * 2005-10-13 2007-04-19 Man Roland Druckmaschinen Ag Verfahren zum Bebildern von Druckformen
EP1837175A1 (fr) 2006-03-22 2007-09-26 MAN Roland Druckmaschinen AG Plaque d'impression et unité d'impression d'une presse
JP2008046447A (ja) * 2006-08-18 2008-02-28 Toray Ind Inc 印刷版の製造方法

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