EP3882036A1 - Coalescence des buses de compensation - Google Patents

Coalescence des buses de compensation Download PDF

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Publication number
EP3882036A1
EP3882036A1 EP20164392.1A EP20164392A EP3882036A1 EP 3882036 A1 EP3882036 A1 EP 3882036A1 EP 20164392 A EP20164392 A EP 20164392A EP 3882036 A1 EP3882036 A1 EP 3882036A1
Authority
EP
European Patent Office
Prior art keywords
print
nozzles
printing
ink
nozzle
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.)
Pending
Application number
EP20164392.1A
Other languages
German (de)
English (en)
Inventor
Annika Kamper
Hans Köhler
Ralf Tita
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.)
Heidelberger Druckmaschinen AG
Original Assignee
Heidelberger Druckmaschinen 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 Heidelberger Druckmaschinen AG filed Critical Heidelberger Druckmaschinen AG
Priority to EP20164392.1A priority Critical patent/EP3882036A1/fr
Priority to CN202110294114.1A priority patent/CN113492594B/zh
Publication of EP3882036A1 publication Critical patent/EP3882036A1/fr
Pending 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
    • 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
    • B41J2/21—Ink jet for multi-colour printing
    • B41J2/2132—Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding
    • B41J2/2139—Compensation for malfunctioning nozzles creating dot place or dot size errors
    • 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
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • 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
    • B41J2/07—Ink jet characterised by jet control
    • B41J2/11—Ink jet characterised by jet control for ink spray
    • 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
    • B41J2/21—Ink jet for multi-colour printing
    • B41J2/2107—Ink jet for multi-colour printing characterised by the ink properties
    • B41J2/2114—Ejecting specialized liquids, e.g. transparent or processing liquids
    • B41J2/2117—Ejecting white liquids
    • 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
    • B41J2/21—Ink jet for multi-colour printing
    • B41J2/2132—Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding
    • B41J2/2146—Print quality control characterised by dot disposition, e.g. for reducing white stripes or banding for line print heads

Definitions

  • the present invention is concerned with a method for compensating for defective printing nozzles in an inkjet printing machine by utilizing the coalescence effect.
  • the invention lies in the technical field of inkjet printing.
  • the status of the print nozzles of the inkjet heads used in the printing units is a decisive criterion for the print quality to be achieved. It is relatively common for individual print nozzles to change their printing behavior over time, be it within the scope of a print job or across several print jobs. This can, for example, relate to the pressure level or a differently printing pressure nozzle. As soon as these deviations exceed certain limit values, the relevant pressure nozzles must be deactivated. It can also happen that pressure nozzles fail completely. The cause of these deviations is mostly due to clogged pressure nozzles. This occurs when ink dries in the nozzles if they are not used for too long. Problems in the ink supply channels can also lead to the error patterns described.
  • coalescence This affects the attraction between individual ink droplets on the print substrate.
  • viscous inks e.g. UV inks
  • the coalescence effect can be very strong, especially in connection with print heads that have a time difference between adjacent nozzles.
  • a "white line” generated by a defective pressure nozzle that has been switched off cannot be closed.
  • the printing error appears even more pronounced, as the ink collects to the right and left of the "white line” and thus increases the difference in contrast even more.
  • the compensation drop is made so large that the gap is closed, the printing speed is reduced due to the time required to generate a large drop.
  • overcompensation in the form of a "dark line” can result.
  • the object of the present invention is therefore to disclose a method for compensating for defective printing nozzles which works reliably and efficiently despite the coalescence effect of the printing inks used.
  • This object is achieved by a method for compensating for defective print nozzles in an inkjet printing machine by means of a computer, the computer correspondingly controlling an increased ink drop volume from directly adjacent print nozzles and these adjacent print nozzles of the inkjet printing machine to compensate for the defective print nozzles, which is characterized accordingly that the defective print nozzles, provided that the print nozzles are printing crookedly, are not deactivated by the computer, but are controlled in such a way that they continue to print more intensely, whereby the intensified ink drops placed between the two ink drops of the directly adjacent print nozzles via a coalescence effect Attracts ink droplets from the directly adjacent print nozzles.
  • the present proceedings therefore have two central points.
  • a preferred development of the method according to the invention is that the print nozzles that print crookedly print only part of the pixels to be set according to the image data with intensified ink drops in the printing direction. This prevents overcompensation and a corresponding dark line from occurring.
  • the proportion of the pixels to be set with intensified ink droplets depends on the printing conditions, the printing ink used and the printing substrate used.
  • next but one, adjacent print nozzles also print with an increased ink drop volume for compensation.
  • the problem of overcompensation with a dark line is inherent. In this case it is recommended to set the frequency of the to adjust accordingly increased ink drop of the defective print nozzle to be compensated.
  • a further preferred development of the method according to the invention is that the print nozzles that print crookedly print with intensified ink droplets only in areas in the print image with high surface coverages.
  • a further preferred development of the method according to the invention is that it is not the defective, crooked printing nozzle, but one of the two directly adjacent printing nozzles that prints more intensely, whereby the compensation of the defective, crooked printing nozzle and its neighboring pressure nozzles is increased by one pressure nozzle to the left or the right shifts right.
  • This approach is particularly useful if the pixel to nozzle mapping was unsuccessful. This means that the defective pressure nozzle determined by means of a detection method was assigned incorrectly. Most detection methods work with optical observations of a generated print image or test pattern and then have to assign corresponding image pixels to real print nozzles, which is done with the aforementioned pixel-to-nozzle mapping.
  • a further preferred development of the method according to the invention is that when several adjacent printing nozzles printing askew, the computer groups them according to a formation rule and classifies them as either intensely printing or normal printing nozzles and controls them accordingly. Kick frequently defective, so crooked printing, print nozzles as a cluster, ie next to each other. In this case, depending on the prevailing printing conditions, formation rules can often be created or specified with which it is possible to determine precisely with which compensation behavior these groups of defective pressure nozzles can best be compensated. So z. B. a group of three defective pressure nozzles exist in which the first pressure nozzle deviates to the left, the second to the right and the third again to the left.
  • the size of the reinforced ink drop is dependent on the color of the printing ink used and the printing substrate used.
  • a white printing ink is used as the printing ink to be compensated.
  • White printing inks often have a particularly high coalescence behavior, which makes the method according to the invention particularly suitable for this type of printing inks.
  • white printing ink is often used in the form of opaque white or primer in order to then continue printing on this white color with the actual printing inks. In this case, overcompensation by increasing the introduction of white printing ink is practically impossible. At most, too much area coverage would be disruptive. On the other hand, a white line, which would de facto be more of a dark line here, would be extremely annoying. Therefore, in this case it is only a matter of closing the disturbing white / dark line and then being able to dry it properly on the applied opaque white.
  • the area of application of the preferred embodiment variant is an inkjet printing machine 7.
  • This is a sheet-fed inkjet printing machine 7 which is controlled by a control computer 6.
  • This printing press 7, as already described failure of individual printing nozzles in the print heads 5 in the printing unit 4 can occur.
  • the result is then "white lines" 9 or, in the case of multicolored printing, distorted color values.
  • An example of such a "white line” 9 in a print image 8 is shown in FIG Figure 2 shown.
  • a modification of the original pixels is carried out in a group of five printing nozzles arranged next to one another.
  • Figure 4 shows this for the resulting pixels.
  • the relevant nozzle N is the nozzle to be compensated and is completely switched off.
  • the first neighboring nozzles n ⁇ 1 are reinforced, or a larger quantity of ink / pixel with larger gray values is used.
  • the compensation strengths are 0 to + 200%, ie pixels up to two gray levels larger.
  • the second neighboring nozzles n ⁇ 2 are weakened, or a smaller amount of ink / pixel with smaller gray values is used.
  • the compensation strengths here are 0 to -200%, ie from no change to two gray levels smaller pixels.
  • Another approach known from the prior art provides, with a group of five pressure nozzles next to one another, to only partially switch off the nozzle N as the nozzle to be compensated and thus to continue printing only in a weakened manner.
  • the first neighboring nozzles n ⁇ 1 are reinforced, or a larger amount of ink / pixels with larger gray values are used. This corresponds to the first compensation approach.
  • the nozzle to be compensated is not switched off or weakened, but rather reinforced in special situations.
  • Figure 5 shows this with the already known example with the five adjacent pressure nozzles. Ie if a nozzle to be compensated injects crooked, but the target position deviates by less than 21um at 1200dpi print resolution and the nozzle belongs to the set of nozzles in which the pressure points of the neighboring nozzles are pulled away from the position of the nozzle to be compensated according to the coalescence effect, Better compensation can thus be achieved if the nozzle to be compensated is itself reinforced. Nozzles with a skew of less than 21 ⁇ m are usually fully functional, i.e. they jet stable droplets, but not directly onto the target position.
  • FIG. 6 An alternative procedure of the method according to the invention is shown Figure 6 .
  • the second neighbors of the nozzle to be compensated are not weakened or provided with the original image pixels, but in special situations are reinforced - typically with the same strength as the direct neighboring nozzles.
  • the nozzle N as the nozzle to be compensated, does not print more intensely, as in the first embodiment, but continues printing normally.
  • the background is that if a nozzle is to be compensated, but the nozzle belongs to the set of nozzles in which the pressure points of the neighboring nozzles are pulled away from the position of the nozzle to be compensated according to the coalescence effect, better compensation can be achieved, even if the second neighbors are reinforced, so that such an amount of ink is created that due to the high amount, in addition to the coalescence effect, a level compensation takes place, which pushes the ink back in the direction of the nozzle to be compensated.
  • Both approaches of the method according to the invention can be used especially in the case of high area coverages, in which the area closure is more important than the exact reaching of the target position of the pixel.
  • a further variant of the method according to the invention consists in using the compensation algorithm according to the invention, but instead of the actual pressure nozzle N to be compensated, the first direct neighboring nozzle to be selected for compensation.
  • the first direct neighboring nozzle to be selected for compensation As a rule, a nozzle is selected that is easy to compensate from the point of view of coalescence and the nozzle actually to be compensated is reinforced as an adjacent nozzle. If the nozzle to be compensated belongs to the group of nozzles that are difficult to compensate, the number of the nozzle to be compensated is decreased by one and this nozzle is now compensated and thus the actual nozzle is reinforced.
  • Figure 7 shows this process for the example already used.
  • a further alternative embodiment of the method according to the invention consists in not only selecting nozzles that are not switched off in groups of malfunctioning pressure nozzles, but also groups nozzles that are specially reinforced. The application for this is typically if nozzles deviate from the target position by less than the print resolution.
  • Nozzles that are reinforced according to the invention are each shown in "bold”.
  • M stands for a completely failed pressure nozzle
  • X for a deactivated pressure nozzle that is compensated for by the neighboring nozzles, otherwise an arrow shows the direction of the deviation.

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  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Ink Jet (AREA)
EP20164392.1A 2020-03-20 2020-03-20 Coalescence des buses de compensation Pending EP3882036A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP20164392.1A EP3882036A1 (fr) 2020-03-20 2020-03-20 Coalescence des buses de compensation
CN202110294114.1A CN113492594B (zh) 2020-03-20 2021-03-19 通过计算机对喷墨印刷机中的缺陷印刷喷嘴补偿的方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20164392.1A EP3882036A1 (fr) 2020-03-20 2020-03-20 Coalescence des buses de compensation

Publications (1)

Publication Number Publication Date
EP3882036A1 true EP3882036A1 (fr) 2021-09-22

Family

ID=69941167

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20164392.1A Pending EP3882036A1 (fr) 2020-03-20 2020-03-20 Coalescence des buses de compensation

Country Status (2)

Country Link
EP (1) EP3882036A1 (fr)
CN (1) CN113492594B (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060007257A1 (en) * 2004-07-07 2006-01-12 Fuji Photo Film Co., Ltd. Image forming apparatus
JP2006051617A (ja) * 2004-08-10 2006-02-23 Brother Ind Ltd インクジェット記録装置用制御装置、インクジェット記録装置用制御プログラム、インクジェット記録装置の制御方法およびインクジェット記録装置
US20060244774A1 (en) * 2005-03-29 2006-11-02 Seiko Epson Corporation Printing device, printing program, printing method, image processing device, image processing program, image processing method, and recording medium in which the program is stored
US20070046715A1 (en) * 2005-08-24 2007-03-01 Fuji Photo Film Co., Ltd. Image forming apparatus
EP2631076A1 (fr) * 2012-02-22 2013-08-28 Fujifilm Corporation Imprimante à jet d'encre et méthode d'impression d'image
US20140063101A1 (en) * 2012-08-28 2014-03-06 Fujifilm Corporation Image forming apparatus and image forming method

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7338144B2 (en) * 2005-09-29 2008-03-04 Xerox Corporation Ink jet printer having print head with partial nozzle redundancy
JP2016041494A (ja) * 2014-08-19 2016-03-31 セイコーエプソン株式会社 印刷装置、印刷プログラムおよび印刷方法
DE102016203917A1 (de) * 2016-03-10 2017-09-14 Heidelberger Druckmaschinen Ag Verfahren zur Kompensation ausgefallener Druckdüsen in einer Inkjet-Druckmaschine
JP6711723B2 (ja) * 2016-08-09 2020-06-17 キヤノン株式会社 インクジェット記録装置およびインクジェット記録方法
JP2018167492A (ja) * 2017-03-30 2018-11-01 株式会社ミマキエンジニアリング インクジェットプリンタ及び印刷方法
DE102019211274A1 (de) * 2018-08-30 2020-03-05 Heidelberger Druckmaschinen Ag Druckdüsenkompensation unter Berücksichtigung benachbarte Flächendeckungen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060007257A1 (en) * 2004-07-07 2006-01-12 Fuji Photo Film Co., Ltd. Image forming apparatus
JP2006051617A (ja) * 2004-08-10 2006-02-23 Brother Ind Ltd インクジェット記録装置用制御装置、インクジェット記録装置用制御プログラム、インクジェット記録装置の制御方法およびインクジェット記録装置
US20060244774A1 (en) * 2005-03-29 2006-11-02 Seiko Epson Corporation Printing device, printing program, printing method, image processing device, image processing program, image processing method, and recording medium in which the program is stored
US20070046715A1 (en) * 2005-08-24 2007-03-01 Fuji Photo Film Co., Ltd. Image forming apparatus
EP2631076A1 (fr) * 2012-02-22 2013-08-28 Fujifilm Corporation Imprimante à jet d'encre et méthode d'impression d'image
US20140063101A1 (en) * 2012-08-28 2014-03-06 Fujifilm Corporation Image forming apparatus and image forming method

Also Published As

Publication number Publication date
CN113492594B (zh) 2023-12-26
CN113492594A (zh) 2021-10-12

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