EP1894728A1 - Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques - Google Patents

Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques Download PDF

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Publication number
EP1894728A1
EP1894728A1 EP06018297A EP06018297A EP1894728A1 EP 1894728 A1 EP1894728 A1 EP 1894728A1 EP 06018297 A EP06018297 A EP 06018297A EP 06018297 A EP06018297 A EP 06018297A EP 1894728 A1 EP1894728 A1 EP 1894728A1
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EP
European Patent Office
Prior art keywords
printed
printing
inkjet
camera
individual
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Withdrawn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
EP06018297A
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German (de)
English (en)
Inventor
Wolfgang Konstantin Baldauf
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.)
BCS machine vision GmbH
Original Assignee
BCS machine vision GmbH
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 BCS machine vision GmbH filed Critical BCS machine vision GmbH
Priority to EP06018297A priority Critical patent/EP1894728A1/fr
Publication of EP1894728A1 publication Critical patent/EP1894728A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
    • B41J29/38—Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
    • B41J29/393—Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/165—Prevention or detection of nozzle clogging, e.g. cleaning, capping or moistening for nozzles
    • B41J2/16579—Detection means therefor, e.g. for nozzle clogging

Definitions

  • Object of the present invention is to propose an optical test method, with the nozzle failures and other emerging Identify incorrect behavior of individual printhead nozzles or the entire printhead at an early stage.
  • the invention relates to a method and a device for automatic quality monitoring of inkjet printheads in digital printing machines by the high-resolution detection and evaluation of defined printing patterns using an image processing system.
  • the image processing system consists essentially of two high resolution cameras, one for the front and one for the back of the paper web, transversely to the direction of transport across the entire width by means of a mechanical shuttle for a few seconds the paper web are moved back and forth. In each case, they take up small sections of a test pattern strip with microscope-like resolution.
  • a connected image evaluation unit evaluates the image data at high speed and checks whether all the inkjet nozzles used are working properly.
  • the inkjet dots of a defined printed test strip are examined for their presence, their contrast, their size, their shape and their position. It also detects the intensity of satellite droplet formation and smearing.
  • tendencies deviations from preset target values are recognized in good time and compared with empirical data of earlier malfunctions of the same printheads. This makes it possible to replace printheads in time, possibly even before it comes to a total failure or other gross malfunction of individual nozzles or the entire printhead. If adjustable limit values are exceeded, warning signals and error messages can be output and, if necessary, the machine is also stopped.
  • the optical camera resolution is on the order of at least 1200 to 2400 ppi (pixels per inch). Because of the high transport speed of the substrate matrix cameras are used. In order to keep the motion blur very small during image acquisition at such high transport speeds of the objects to be detected, a combination of a short electronic shutter (shutter) of the camera and very short and bright strobe flashes are used. The required short exposure time is on the order of down to 2 ⁇ sec. The required sufficient field illumination is achieved by very bright flashes of light.
  • the "defined print pattern” is either a special test strip, which is located in the sheet edge area to be cut off later anyway, or specially selected, known cutouts in the used print field. Especially suitable are horizontal lines and line sections, where the behavior of the nozzles can be observed, especially at the edges.
  • "Defined Print Pattern” means the expected print pattern to be captured by the camera at a particular location. This is defined as a desired pressure pattern by a teach-in process or by the pressure-underlying record. Whether the defined print pattern is selected from the printed work area or is a test strip printed specifically for this purpose, in both cases the defined print pattern should meet some basic conditions. Each print dot position within the image window must be clearly assignable to a particular nozzle of the print head and printed at least once and printed at least once. The printed dots (Ink dots) should occur as isolated as possible in order to minimize the overlay by the influence of several adjacent pressure points on a specific point of the print pattern.
  • test strip definition is an example of such a test strip definition:
  • the test strip consists of 9 pressure point lines, of which only 5 are printed. Each nozzle prints 1 to 4 dark dots. Lines 1, 3, 5 and 9 are always empty (---------).
  • line 2 is a test pattern, where only every second point is printed, in line 4, the inverted pattern.
  • line 6 there is a position code.
  • the position code consists of a sequence of data blocks with 21 dot positions each. Each data block consists of an always identical start code (-xxx-) and an incremental 8-bit binary counter: 00000001 b, 00000010b, 00000011b, 00000100b, 00000101b ...
  • the paper may shift sideways, it may slightly buckle, warp, twist, stretch, or it may shrink slightly. Therefore, the exact position of the image section in the print pattern itself must be included, because even a very precise absolute position sensor on the camera positioning device can not measure exactly where the camera image field in the test strip and thus could not be determined which pressure point through which inkjet Nozzle has been printed. That is, without additional information in the image itself, it would not be possible to determine which pressure point is to be assigned exactly to which nozzle. It is less the exact absolute position of the pressure points on the paper important, but the relative position to the adjacent pressure points.
  • test strip includes such - just a few millimeters wide - individual dot sequences with a position code (e.g., a counter incrementing over the printhead width).
  • FIG. 1 shows an embodiment for double-sided inkjet monitoring in a web press.
  • the paper web (1) passes through the front-side printing roll (2) with the front-side inkjet printing head (6) or with a number of such print heads.
  • the back of the paper web is printed by means of one or a series of inkjet printheads (7).
  • Each inkjet print head (6,7) has a large number of parallel inkjet nozzles.
  • the inline inkjet inspection is done for the front of the paper web (4,8,9,10) and for the back (5,11,12,13), if it is double-sided printing.
  • the inspection has in each case a camera movement unit (10, 13) transversely to the transport direction of the paper web.
  • the movement units (10, 13) may be e.g. have a linear motor and the sensor units (8,9 and 11,12) over the entire width of the paper web.
  • the sensor units consist here of high-resolution, fast, triggerable matrix cameras (9,12) including macro lenses, as well as LED flash units (8,11), which are preferably equipped with monochrome black printing with infrared LEDs.
  • the image processing electronics (16) moves, positions and triggers the sensor units (8,9 and 11,12), generates the pulses for the flash lights (8,11) and has a communication interface to the printing press.

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  • Ink Jet (AREA)
EP06018297A 2006-09-01 2006-09-01 Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques Withdrawn EP1894728A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06018297A EP1894728A1 (fr) 2006-09-01 2006-09-01 Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06018297A EP1894728A1 (fr) 2006-09-01 2006-09-01 Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques

Publications (1)

Publication Number Publication Date
EP1894728A1 true EP1894728A1 (fr) 2008-03-05

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP06018297A Withdrawn EP1894728A1 (fr) 2006-09-01 2006-09-01 Surveillance du fonctionnement de têtes d'impression à jet d'encre dans des machines d'impression numériques

Country Status (1)

Country Link
EP (1) EP1894728A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008021447A1 (de) * 2008-04-29 2009-11-05 Manroland Ag Verfahren zum Betreiben einer in eine Rollendruckmaschine integrierten Bearbeitungseinrichtung
DE102009023963A1 (de) 2009-06-05 2010-12-09 Robert Bosch Gmbh Verfahren zum Bestimmen eines Qualitätsmaßes für ein von einer Bearbeitungsmaschine bearbeitetes Produkt
WO2015032127A1 (fr) * 2013-09-03 2015-03-12 北大方正集团有限公司 Procédé et dispositif pour vérifier une buse d'imprimante à jet d'encre
DE102014108342A1 (de) * 2014-06-13 2015-12-17 Océ Printing Systems GmbH & Co. KG Optische Erfassung und Bewertung von Refreshlines

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6094280A (en) * 1996-11-08 2000-07-25 Canon Kabushiki Kaisha Method and apparatus for correcting print density by printhead, printhead corrected by this apparatus, and printing apparatus using this printhead
US6106094A (en) * 1996-01-30 2000-08-22 Neopt Corporation Printer apparatus and printed matter inspecting apparatus
WO2002077108A2 (fr) * 2001-03-21 2002-10-03 Macdermid Colorspan, Inc. Sous-ensembles mecaniques cooperants pour imprimante numerique grand format a jet d'encre, a chariot balayeur
US20040021724A1 (en) * 2002-07-30 2004-02-05 Fuji Photo Film Co., Ltd. Image recording apparatus
US20060092199A1 (en) * 2004-11-04 2006-05-04 White John M Methods and apparatus for aligning print heads

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6106094A (en) * 1996-01-30 2000-08-22 Neopt Corporation Printer apparatus and printed matter inspecting apparatus
US6094280A (en) * 1996-11-08 2000-07-25 Canon Kabushiki Kaisha Method and apparatus for correcting print density by printhead, printhead corrected by this apparatus, and printing apparatus using this printhead
WO2002077108A2 (fr) * 2001-03-21 2002-10-03 Macdermid Colorspan, Inc. Sous-ensembles mecaniques cooperants pour imprimante numerique grand format a jet d'encre, a chariot balayeur
US20040021724A1 (en) * 2002-07-30 2004-02-05 Fuji Photo Film Co., Ltd. Image recording apparatus
US20060092199A1 (en) * 2004-11-04 2006-05-04 White John M Methods and apparatus for aligning print heads

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008021447A1 (de) * 2008-04-29 2009-11-05 Manroland Ag Verfahren zum Betreiben einer in eine Rollendruckmaschine integrierten Bearbeitungseinrichtung
DE102009023963A1 (de) 2009-06-05 2010-12-09 Robert Bosch Gmbh Verfahren zum Bestimmen eines Qualitätsmaßes für ein von einer Bearbeitungsmaschine bearbeitetes Produkt
WO2015032127A1 (fr) * 2013-09-03 2015-03-12 北大方正集团有限公司 Procédé et dispositif pour vérifier une buse d'imprimante à jet d'encre
US9662889B2 (en) 2013-09-03 2017-05-30 Peking University Founder Group Co., Ltd. Method and device for checking nozzle of inkjet printer
DE102014108342A1 (de) * 2014-06-13 2015-12-17 Océ Printing Systems GmbH & Co. KG Optische Erfassung und Bewertung von Refreshlines

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