EP0916113B1 - Procede pour optimiser une representation de demi-teintes sur un photoconducteur de systemes d'impression et de copie electrophotographique - Google Patents

Procede pour optimiser une representation de demi-teintes sur un photoconducteur de systemes d'impression et de copie electrophotographique Download PDF

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Publication number
EP0916113B1
EP0916113B1 EP97932732A EP97932732A EP0916113B1 EP 0916113 B1 EP0916113 B1 EP 0916113B1 EP 97932732 A EP97932732 A EP 97932732A EP 97932732 A EP97932732 A EP 97932732A EP 0916113 B1 EP0916113 B1 EP 0916113B1
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EP
European Patent Office
Prior art keywords
toner
optical density
bias potential
value
max
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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.)
Expired - Lifetime
Application number
EP97932732A
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German (de)
English (en)
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EP0916113A1 (fr
Inventor
Volkhard Maess
Martin Schleusener
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.)
Canon Production Printing Germany GmbH and Co KG
Original Assignee
Oce Printing Systems GmbH and Co KG
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Publication of EP0916113A1 publication Critical patent/EP0916113A1/fr
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • G03G15/5033—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor
    • G03G15/5041—Detecting a toner image, e.g. density, toner coverage, using a test patch

Definitions

  • the invention relates to a method for optimizing a Halftone display by optimizing the Toner deposition intensity on a photoconductor from electrophotographic printing and copying equipment.
  • a latent image is generated.
  • a photoconductor is placed on a defined one Charging potential and then be charged in Depends on the method used in the expression areas appearing white or black.
  • the then exposed areas have a Charging potential lower discharge potential.
  • the generated latent image is then developed by in Depends on the method used on the exposed or unexposed areas of toner applied so that these areas appear black in the printout.
  • the toner commonly used is preferably by two-component toner, which consists of a Carrier component and micro toner exists.
  • the Two-component toner is dependent on that applied procedures positively or negatively charged.
  • the image developed on the photoconductor is then opened Transfer paper or another record carrier and then in a fuser by heating in the Melted record carrier or with this through at Melting of the toner image resulting adhesion forces connected.
  • the photoconductor After transferring the image from the photoconductor to the The photoconductor becomes a record carrier in preparation for Generation of the next image cleaned and complete discharged.
  • Such fluctuations can be caused, for example, by Process parameters, such as the charging potential to which the Photoconductor is charged at the beginning of each printing process is, by the discharge potential, which certain areas of the photoconductor after exposure, and by Variations in the exposure intensity caused become.
  • the charging and / or discharging potential of the In particular, the photoconductor can be from the manufacturing batch that Operating time, the temperature and the cyclical load of the Dependent on the photoconductor.
  • a toner deposition intensity i.e. the amount of toner that is in an area to be blackened deposited on the photoconductor is essentially from the humidity and the Toner concentration in the two-component toner, i.e. the Mixing ratio between microtoner and carrier component, dependent.
  • the toner deposition intensity is from the triboelectric excitation state of the Two-component toner depending, for example, in turn on the temperature, humidity, duration of use, the intensity and duration of the mixing of the Two-component toner and the amount of the mixture supplied fresh toner is dependent.
  • toner brands are understood to mean areas which are arranged outside the printed image on the photoconductor, and exposed to process monitoring and control and be developed.
  • DE-A1-38 43 672 describes a method for optimizing a toner deposit intensity in analog working Known copiers, in which depending on one optical density of a toner mark a bias potential and / or a toner concentration is changed.
  • a toner brand an unscreened "image pattern" with full-surface coloring used.
  • the well-known toner brands are specially designed to control one individual process parameters designed or suitable.
  • To Regulation of the various parameters of the overall process are different, differently designed Toner brands used.
  • the object of the invention is a method for optimizing the halftone display in electrophotographic Printing and copying equipment by setting the Process parameters influencing the print image depending to be provided by a raster toner brand at which by scanning the raster toner mark all the printed image influencing essential parameters are detected so that it is possible by setting a few parameters optimal halftone reproduction with high resolution to reach.
  • this is a method for Optimize a halftone display by optimizing the Toner deposition intensity in electrophotographic printing and Copying devices by the features in claim 1 or 9 reached.
  • Advantageous further developments are the subject of to claim 1 or 9 directly or indirectly related claims.
  • a photoconductor is used creates a halftone toner mark with fine halftone elements and their integral optical density averaged over the surface determined.
  • a bias voltage is changed and / or a density Toner concentration changed.
  • toner depositing intensity or to influence the optical density of a toner mark is a variation of the toner concentration, i.e. of Mixing ratio of microtoner and carrier component.
  • the toner deposition intensity a photoconductor.
  • toner concentration simply by adding toner to the two-component developer can be increased, but decreasing the Toner concentration only through more complex "printing" can be achieved.
  • Print out a Perform multiple print or copy operations understood, it is colored as possible Pictures should act to get one as quickly as possible large amount of toner from the two-component developer remove.
  • the method according to the invention Possibilities of changing the bias voltage and the Toner concentration linked together, creating a Fluctuations in the toner deposition intensity or the optical Density of a toner brand and thus the quality of one Halftone is kept within extremely small limits becomes.
  • the method according to the invention thus has in particular the advantage that already through the targeted change of two parameters fluctuations of others on the system acting parameters are compensated. This is about it is the process parameters described above, such as for example, the batch of photoconductor whose Duration of use, the temperature and the cyclical load of the Photoconductor and humidity.
  • the bias voltage increases once the optical Density of the toner mark has fallen below a target value. At the same time, however, the optical density of the toner mark may have not fallen below a minimum value and the bias voltage must be below a predetermined upper limit lie.
  • the bias voltage is reduced. Lowering the bias voltage is only performed when the bias voltage is greater than a predetermined lower limit.
  • optical density of the toner mark exceeds the toner concentration of the Two-component developer reduced by toner is printed out.
  • the toner concentration is corresponding increases as soon as the optical density of the toner mark falls below the lower limit.
  • the current bias voltage set a target value to prevent the optical Density the upper limit due to the time delay Effect of increasing the toner concentration in the short term exceeds.
  • Such an overshoot of the optical density can also can be avoided by, for example, between the Minimum value of the bias potential and the maximum value of the bias potential additional comparative values are provided.
  • Fig.1a To 1d is an example of a control start if the start is too high Toner concentration described.
  • the optical density OD has a maximum value OD max . Since the optical density OD should ideally be reduced to a desired value OD s and in the present example the toner deposition intensity on a photoconductor and thus also the optical density OD of a toner mark can be reduced by keeping the bias voltage V B as low as possible in the present case the bias voltage V B at time t 0 has a lower limit value V B min .
  • FIG. 1c depending on the printing or copying cycles, a toner request is shown, which is not carried out at time t 0 , since, as can be seen from FIG. 1a, the optical density is above the target value OD s .
  • the toner concentration in the two-component developer is also shown in FIG. 1d as a function of printing or copying cycles.
  • the bias voltage V B is raised by one step above the minimum value V b min (see FIG. 1b), thereby reducing the toner deposition intensity on the photoconductor to increase.
  • the bias voltage V B is increased by a further voltage step as soon as the optical density OD of the toner mark has dropped below the target value of the optical density OD s .
  • the toner delivery is activated, as can be seen in FIG. 1c.
  • the bias voltage V B is kept at its maximum value V B max at time t 3 .
  • the toner concentration increases from time t 3 .
  • the optical density OD (FIG. 1) also increases and at a time t 4 is already above the target value OD s ; the bias voltage V B (Fig.1b) is therefore reduced again.
  • the bias voltage V B is reduced until the optical density OD falls below the target value OD s .
  • the bias voltage V B is increased or maintained as a function of the value of the optical density OD from a time t 6 . From time t 6 , the method according to the invention thus proceeds analogously to the above steps carried out from time t 1 .
  • step 1c shows a flow chart of a preferred embodiment of the method according to the invention for optimizing a toner deposition intensity in electrophotographic printing and copying devices.
  • the photoconductor is charged to a charging potential and only exposed with a set or regulated exposure energy, so that a discharging potential reaches a predetermined target value.
  • the bias potential is set to a standard value V B s .
  • Step 2 asks whether the printing or Copier is in print mode or not. If the printing or copying device is not yet in Printing operation, but for example still in one Warm-up phase, so there is a on the photoconductor Halftone toner mark exposed and then developed (Step 3). During printing, in addition to Raster toner mark also a printed page on the photoconductor exposed and developed (step 3 ').
  • step 4 the optical density OD of the screen toner mark generated in step 3 or 3 'is measured. If the decision in step 5 is "yes", since the optical density OD of the halftone toner mark corresponds to the desired target value OD s , further regulation of the toner deposition intensity or the optical density OD is not necessary, so that steps 6 to 10 or 6 ' to 10 'are omitted and steps 11a to 11c are carried out, in which the photoconductor is cleaned, the photoconductor charge is deleted and the photoconductor is subsequently recharged. Following steps 11a to 11c, step 2 is returned to for the next printing process.
  • step 6 determines whether or not the optical density OD of the halftone toner mark is greater than the target value OD s . If the target value OD s is greater, step 7 examines whether the optical density OD of the halftone toner mark is greater than a maximum value OD max or not. If the optical density is greater than the maximum value OD max , the toner concentration is reduced in step 8, for example by printing out toner.
  • step 9 it is determined in step 9 whether or not the bias potential V B is greater than a minimum value V B min . If the bias potential V B is greater than the minimum value V B min , the bias potential V B can be reduced in step 10 to reduce the optical density OD or the toner deposition intensity.
  • steps 11a to 11c are carried out, ie the photoconductor is cleaned, the photoconductor charge is deleted and the photoconductor is then recharged. Following steps 11a to 11c, step 2 is continued again.
  • step 6 If the decision in step 6 is "no", ie the optical density OD of the halftone toner mark is not greater than the target value OD S , steps 7 'to 10' are carried out instead of steps 7 to 10.
  • step 7 ' it is determined whether or not the optical density OD is less than a minimum value OD min . If the optical density is less than the minimum value OD min , the toner concentration is increased in step 8 ′ by adding toner to the two-component developer. However, if the optical density OD is not less than the minimum value OD min , a decision is made in step 9 'as to whether the bias potential V B is less than a maximum value V B max . If the decision is "yes", then the bias potential V B is raised in step 10 '.
  • step 11a to 11c are carried out as described above. Following step 11c, the optimization process is also repeated again from step 2.
  • FIG. 3 shows a detail of a Raster toner mark as in an electrophotographic Printer with a resolution of 600 dpi and an LED character generator Application.
  • the halftone toner mark is made of MIP micropixels Macropixels MAP built.
  • a micropixel MIP with the Edge length a (in this case 42 ⁇ m) defines the smallest colorable stain that is used with the LED character generator the image of a single LED light spot on the photoconductor. The length a becomes also called micropixel pitch.
  • a raster structure S is now represented in the macropixel MAP, which corresponds to a fine gray value in the gray value scale (halftone display).
  • This fine structure S is dimensioned such that in the macropixel MAP (1,1) at least any micropixel is not colored with toner.
  • the structure S is colored and the surrounding micropixels remain toner-free or vice versa. In the example shown with reverse development in which the charged photoconductor is discharged depending on the character, the structure S remains toner-free.
  • the size of this toner brand is however any. It depends on the location and the type of Scanning.
  • a halftone tone mark can also be used individual lines extending in the Y direction.
  • the lines then have a width in the X direction the width a of a micropixel and any length.
  • On Line macropixels then have a width b in the X direction and a length in the Y direction which can be a multiple of b.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Or Security For Electrophotography (AREA)
  • Developing For Electrophotography (AREA)

Abstract

L'invention concerne un procédé pour optimiser une représentation de demi-teintes par optimisation de l'intensité de dépôt du toner, dans des systèmes d'impression et de copie électrophotographiques. Ledit procédé consiste, après détermination des valeurs fondamentales, à produire une empreinte de toner quadrillée sur un photoconducteur, avant et pendant une opération d'impression ou de copie, puis à déterminer la densité optique de l'empreinte de toner quadrillée. Ce procédé consiste ensuite à réduire un potentiel de polarisation pour la valeur instantanée, si la densité optique dépasse une valeur seuil et si le potentiel de polarisation est supérieur à une valeur minimale. Le photoconducteur est déchargé, nettoyé et rechargé avant d'être réinitialisé.

Claims (14)

  1. Procédé d'optimisation de la représentation en demi-teintes dans des appareils d'impression ou de copie électrographiques, dans lequel un potentiel de polarisation (VB) et/ou une concentration en toner sont modifiés en fonction d'une densité optique (OD), intégralement déterminée sur la surface, d'une marque de toner tramée, la marque de toner étant constituée par des répétitions de macropixels bidimensionnels (MAP), un macropixel (MAP) étant plus grand d'au moins une dimension que la dimension a de la trame constituant le macropixel et étant inférieur à 0,5 mm, et le macropixel comportant au moins un micropixel (MIP) non coloré avec du toner et au moins un micropixel (MIP) coloré avec du toner.
  2. Procédé selon la revendication 1, dans lequel le potentiel de polarisation (VB) est élevé par rapport à la valeur en cours lorsque la densité optique (OD) est inférieure à une valeur de consigne (ODS) et supérieure à une valeur minimale (ODmin), et que le potentiel de polarisation (VB) est inférieur à une valeur maximale (VB max).
  3. Procédé selon la revendication 1, dans lequel le potentiel de polarisation (VB) reste inchangé lorsque la densité optique (OD) correspond à la valeur de consigne (ODS).
  4. Procédé selon la revendication 1, dans lequel le potentiel de polarisation (VB) est abaissé par rapport à la valeur en cours lorsque la densité optique (OD) est supérieure à une valeur de consigne (ODS) et inférieure à une valeur maximale (ODmax), et que le potentiel de polarisation (VB) est supérieur à une valeur minimale (VB min).
  5. Procédé selon la revendication 1 ou 2, dans lequel la concentration en toner est élevée lorsque la densité optique (OD) est inférieure à la valeur minimale (ODmin).
  6. Procédé selon la revendication 5, dans lequel le potentiel de polarisation (VB) est abaissé pendant, ou peu avant le moment de l'élévation de la concentration en toner.
  7. Procédé selon la revendication 1 ou 4, dans lequel la concentration en toner est abaissée lorsque la densité optique (OD) est supérieure à une valeur maximale (ODmax).
  8. Procédé selon l'une des revendications précédentes, dans lequel des valeurs de compensation supplémentaires sont prévues entre la valeur minimale (VB min) du potentiel de polarisation et la valeur maximale (VB max) du potentiel de polarisation.
  9. Procédé d'optimisation d'une représentation en demi-teintes dans des appareils d'impression ou de copie électrographiques, consistant à
    a) régler des valeurs de base,
    b) générer une marque de toner tramée sur un photoconducteur avant ou pendant un processus d'impression ou de copie, la marque de toner étant constituée par des répétitions de macropixels bidimensionnels (MAP), un macropixel (MAP) étant plus grand d'au moins une dimension que la dimension a de la trame constituant le macropixel et étant inférieur à 0,5 mm, et le macropixel comportant au moins un micropixel (MIP) non coloré avec du toner et au moins un micropixel (MIP) coloré avec du toner,
    c) déterminer une densité optique (OD), mesurée intégralement sur la surface, de la marque de toner tramée,
    d) abaisser un potentiel de polarisation (VB) par rapport à une valeur en cours lorsque la densité optique (OD) est supérieure à une valeur de consigne (ODS), et que le potentiel de polarisation (VB) est supérieur à une valeur minimale (VB min),
    e) décharger, nettoyer et recharger le photoconducteur, puis
    f) répéter les étapes b) à e).
  10. Procédé selon la revendication 9, dans lequel à une étape d1) remplaçant l'étape d), le potentiel de polarisation (VB) et la concentration en toner sont abaissés par rapport à la valeur en cours lorsque la densité optique (OD) est supérieure à une valeur maximale (ODmax) et que le potentiel de polarisation (VB) est supérieur à une valeur minimale (VB min).
  11. Procédé selon la revendication 9, dans lequel à une étape d2) remplaçant l'étape d), le potentiel de polarisation (VB) est relevé lorsque la densité optique (OD) est inférieure à une valeur de consigne (ODS) et supérieure à une valeur minimale (ODmin), et que le potentiel de polarisation (VB) est inférieur à une valeur maximale (VB max).
  12. Procédé selon la revendication 9, dans lequel à une étape d3) remplaçant l'étape d), le potentiel de polarisation (VB) est relevé lorsque la densité optique (OD) est inférieure à une valeur minimale (ODmin), et que le potentiel de polarisation (VB) est inférieur à une valeur maximale (VB max).
  13. Procédé selon la revendication 9, dans lequel à une étape d4) remplaçant l'étape d), la concentration en toner est abaissée lorsque la densité optique (OD) est supérieure à une valeur maximale (ODmax), et que le potentiel de polarisation (VB) est inférieur ou égal à une valeur minimale (VB min).
  14. Procédé selon la revendication 9, dans lequel à une étape d5) remplaçant l'étape d), la concentration en toner est relevée lorsque la densité optique (OD) est inférieure à une valeur minimale (ODmin), et que le potentiel de polarisation (VB) est supérieur ou égal à une valeur maximale (VB max).
EP97932732A 1996-08-02 1997-07-02 Procede pour optimiser une representation de demi-teintes sur un photoconducteur de systemes d'impression et de copie electrophotographique Expired - Lifetime EP0916113B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19631378 1996-08-02
DE19631378 1996-08-02
PCT/DE1997/001405 WO1998006011A1 (fr) 1996-08-02 1997-07-02 Procede pour optimiser une representation de demi-teintes sur un photoconducteur de systemes d'impression et de copie electrophotographique

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EP0916113A1 EP0916113A1 (fr) 1999-05-19
EP0916113B1 true EP0916113B1 (fr) 2002-10-30

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US (1) US6081677A (fr)
EP (1) EP0916113B1 (fr)
DE (1) DE59708627D1 (fr)
WO (1) WO1998006011A1 (fr)

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DE102008056967A1 (de) 2008-11-11 2010-05-20 OCé PRINTING SYSTEMS GMBH Verfahren zur Regelung der Zeichenbreite von von einem elektrografischen Druckgerät auf einem Aufzeichnungsträger zu druckenden Zeichen
DE102008056966A1 (de) 2008-11-11 2010-05-20 OCé PRINTING SYSTEMS GMBH Verfahren zur Regelung der Tonereinfärbung von Ladungsbildern auf einem Fotoleiterelement bei einem elektrografischen Druckgerät

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DE102006058580A1 (de) * 2006-12-12 2008-06-26 OCé PRINTING SYSTEMS GMBH Verfahren und Anordnung zum Einstellen der Punktgröße von mit Hilfe eines elektrografischen Druck- oder Kopiersystems erzeugten Druckbildern
DE102007009070A1 (de) * 2007-02-23 2008-08-28 OCé PRINTING SYSTEMS GMBH Verfahren und Vorrichtung zum Erfassen eines elektrischen Potentials sowie von elektrischen Ladungen ein einem Drucker oder Kopierer
DE102009034227A1 (de) 2009-07-22 2011-01-27 OCé PRINTING SYSTEMS GMBH Verfahren und Vorrichtung zur Regelung einer Eigenschaft eines auf einem Trägermaterial gedruckten Druckbildes

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008056967A1 (de) 2008-11-11 2010-05-20 OCé PRINTING SYSTEMS GMBH Verfahren zur Regelung der Zeichenbreite von von einem elektrografischen Druckgerät auf einem Aufzeichnungsträger zu druckenden Zeichen
DE102008056966A1 (de) 2008-11-11 2010-05-20 OCé PRINTING SYSTEMS GMBH Verfahren zur Regelung der Tonereinfärbung von Ladungsbildern auf einem Fotoleiterelement bei einem elektrografischen Druckgerät

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EP0916113A1 (fr) 1999-05-19
WO1998006011A1 (fr) 1998-02-12
DE59708627D1 (de) 2002-12-05
US6081677A (en) 2000-06-27

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