EP1254559A2 - Procede et dispositif de regulation de la concentration de toner dans un processus electrographique - Google Patents

Procede et dispositif de regulation de la concentration de toner dans un processus electrographique

Info

Publication number
EP1254559A2
EP1254559A2 EP01927648A EP01927648A EP1254559A2 EP 1254559 A2 EP1254559 A2 EP 1254559A2 EP 01927648 A EP01927648 A EP 01927648A EP 01927648 A EP01927648 A EP 01927648A EP 1254559 A2 EP1254559 A2 EP 1254559A2
Authority
EP
European Patent Office
Prior art keywords
toner
setpoint
printing
sensor
controller
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Withdrawn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
EP01927648A
Other languages
German (de)
English (en)
Inventor
Alexander Kreiter
Heiner Reihl
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
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 Oce Printing Systems GmbH and Co KG filed Critical Oce Printing Systems GmbH and Co KG
Publication of EP1254559A2 publication Critical patent/EP1254559A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0848—Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
    • G03G15/0849—Detection or control means for the developer concentration
    • 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
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0848—Arrangements for testing or measuring developer properties or quality, e.g. charge, size, flowability
    • G03G15/0849—Detection or control means for the developer concentration
    • G03G15/0855—Detection or control means for the developer concentration the concentration being measured by optical means
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/00025—Machine control, e.g. regulating different parts of the machine
    • G03G2215/00029—Image density detection
    • G03G2215/00033—Image density detection on recording member
    • G03G2215/00037—Toner image detection
    • G03G2215/00042—Optical detection

Definitions

  • the invention relates to a device and a method for regulating an electrographic printing or copying process.
  • the invention particularly relates to a device for regulating the coloring of a toner image on a carrier material.
  • the developer station contains a developer mixture of toner particles and carrier particles, e.g. ferromagnetic iron particles, the proportion of toner particles ⁇ in the developer mixture being adjustable by the replenishment of toner.
  • WO 99/36834 describes a device and a method for printing or copying, in which a toner mark is scanned by at least one sensor at at least two measuring locations and the respective optical toner density, i.e. the toner area coverage at these measuring locations is mapped as an electrical signal. Depending on the difference or the quotient of the amounts of the signals at these two measuring locations, the proportion of toner in the developer mixture is set.
  • the content of patent application WO 99/36834 is hereby incorporated by reference into the present description.
  • EP 403 523 B1 describes an electrographic process in which a number of process parameters are monitored and regulated, including the toner concentration in a developer station. For this purpose, it is provided to generate a toner mark on a photoconductor drum, to scan the mark with a reflected light sensor on the photoconductor drum and to measure the measured value for controlling the toner replenishment in the winder station to use.
  • the full-surface toner mark is produced on the side edge of the photoconductor drum, so that it relates to the web-shaped recording medium provided with ' edge holes only in the area of the edge holes and. so that it does not lie in the actual writing area of the recording medium or the photoconductor drum.
  • the toner mark is thus only to be made relatively small, as a result of which the scanning area and thus also the measuring accuracy is limited, in particular transversely to the transport direction of the photoconductor drum or of the recording medium.
  • web-shaped recording media e.g. of so-called continuous paper
  • paper waste arises because the recording medium printed in this way is no longer available for printing with other information.
  • edge effects occur on the edges of a photoconductor, e.g. of the electric field, which makes the meaningfulness of a measurement. is weakened in this area. The narrower a toner mark, the more overlapping edge effects that are caused by the edges of the toner mark.
  • EP 403 521 Bl it is described that the print image coloring by changing the Tonerförde- • approximate quantity is regulated in the developer station.
  • a toner mark is generated on the photoconductor and scanned.
  • the scanning result is compared to a control threshold and the comparison result is used to control the toner delivery into the developer station.
  • WO-A-97/17535 describes an electrophotographic printing device which contains compensating elements, in particular swing arms, springs and other tendons, which are intended to avoid fluctuations in the position of the recording medium in the area of the transfer printing zone. This is particularly necessary in a duplex operation in which the web-shaped recording medium is guided twice through the same transfer printing station. Regarding the regulation of the electrographic process, however, nothing significant can be found in this publication.
  • WO-A-00/41038 (sign of the applicant: 990101P) it is known to provide two operating states in an electrographic printing device.
  • a toner mark is generated on a photoconductor drum, the density of the toner mark is scanned and the toner mark is then removed again from the photoconductor drum.
  • the sampled toner density value is used to regulate the toner concentration in the developer station and is particularly influenced in a target toner concentration value and / or in a regulation threshold value.
  • information to be printed is generated on the photoconductor drum as a toner image and later printed on the recording medium.
  • WO-A-99/36834 describes a control method for the toner developer mixture, a so-called two-component development system, in an electrographic printing or copying machine.
  • a toner mark is scanned at at least two points with respect to the transport direction of the photoconductor drum.
  • an electographic developer station in which the toner coloring is controlled with a BIAS voltage.
  • Electrographic printer or copier usually have a toner carrier, for example a fot 'oleiter on which a latent image such as is produced by exposure.
  • a developer station is used to color the latent image with toner.
  • This developer station contains a developer mixture of toner particles and carrier particles.
  • a toner mark is colored with toner on the toner carrier and this toner mark is scanned, for example with the aid of a reflex sensor.
  • the reflex sensor irradiates the surface of the toner carrier, for example the surface of the photoconductor, with a predetermined radiation and detects the radiation reflected by the toner carrier or by the toner on the toner carrier.
  • the reflex sensor outputs an output signal which serves as a measure for the area coverage of the toner mark, ie for the optical toner density of the toner mark.
  • the signal level is also dependent on the reflection behavior of the toner and on the surface of the toner carrier.
  • the toner area coverage is essentially dependent on the toner supply in the developer zone, i.e. of the toner supply at the contact surface of the developer station and surface of the toner carrier, of the toner concentration in the developer mixture, of the electrostatic charging behavior of the surface of the photoconductor, of the triboelectric behavior of the developer mixture, i.e. the adhesive force between carrier particles and toner particles, and on the shape and size of the toner particles in the developer mixture.
  • an image recording device in which a toner through the sensor has two toner marks scanned on a photoconductor drum.
  • the sensor contains two photo receivers that evaluate the reflectance of the two toner marks.
  • the toner marks are arranged transversely to the direction of movement of the photoconductor drum, one toner mark having a high toner density and the other toner mark having a low toner density.
  • a pre-tension is set for the developer unit.
  • the information to be printed is generated as an intermediate toner image on an intermediate image carrier with a photoconductor drum and later transferred in a transfer zone from a transfer surface, for example from the surface of the photoconductor drum or from a transfer transfer tape, to a recording medium ,
  • a transfer surface for example from the surface of the photoconductor drum or from a transfer transfer tape
  • To control the toner density and thus also the color density i.e.
  • a toner mark is produced on the electrographic intermediate image carrier for the optical density of the recorded information on the intermediate image carrier (e.g. a photoconductor drum) or the final image carrier (e.g. paper).
  • the toner mark is scanned on the intermediate image carrier at least in some areas and later removed from the intermediate image carrier.
  • the optical density in particular is scanned at the toner mark.
  • the toner concentration is then regulated in a developer station with the measured value, in particular density value, so that the coloring can be kept constant.
  • Period between the generation of the toner mark on the intermediate image carrier and the removal of the toner mark from the intermediate Transfer of the intermediate toner image from the transfer printing surface to the recording medium is prevented at least temporarily. This hindrance to transfer printing is prevented, in particular, during a period in which the token passes through the transfer printing zone. Prevention of transfer printing can be done in particular by separating / lifting the recording medium from the transfer printing surface or by electrostatic measures.
  • the invention provides for the operation of an electrographic
  • Printing or copying machine in particular two operating states.
  • the first operating state the so-called measurement cycle
  • a toner mark is generated on the intermediate image carrier, the density of the toner mark is scanned and the toner mark is then removed from the intermediate image carrier again.
  • the sampled toner density value is used to regulate the toner concentration in the developer station and finds particular influence in a nominal toner concentration value and / or in a regulating threshold value.
  • the second operating state information to be printed is generated on the intermediate image carrier as a toner image and later printed on the recording medium.
  • the toner concentration is controlled in particular with the toner concentration or control threshold value determined from the first operating state.
  • the recording medium in the first operating state is at least temporarily separated or lifted off from the transfer printing surface, in particular from the intermediate image carrier.
  • the invention is therefore suitable for generating the toner mark on the intermediate image carrier in an area in which the information to be printed on the record carrier is also output.
  • the record carrier is in particular web-shaped and can be made of paper, for example.
  • a photoconductor drum is provided as the intermediate carrier on which the toner mark is produced.
  • the recording medium is held by it for at least one revolution.
  • ⁇ s ⁇ Q ⁇ -i HH li d DJ: tx T3 ⁇ 3 co o 3 ⁇ - ⁇ - tr er CQ N 3 N ⁇ - 3 ⁇ -3 ⁇ ⁇ er ⁇ 3 tr d 3 ⁇ Q ⁇ O ⁇ tx H ⁇ ⁇ - ⁇ - tx iQ 3 ⁇ rt ⁇ - ⁇ ⁇ ⁇ .Hi s: o ⁇ o tr ⁇ - DJ d ⁇ - ⁇ ⁇ - ⁇ iQ ⁇ H ⁇ -i li tu ⁇ - ⁇ - 1-5 ⁇ ⁇ tu tx ⁇ 3 o tr d O ⁇ ⁇ H
  • te has.
  • shape recognition of a large-area mark can be used advantageously.
  • toner marks are generated and scanned cyclically in an electrographic process — only at relatively large page intervals, for example only after a few thousand printed pages.
  • the toner concentration is then different, i.e. based on other measured variables only.
  • Such a different measurand can e.g. be the toner concentration measured in the developer station with a toner concentration sensor.
  • a target value is determined from the measured value determined by the toner mark (toner density, toner mark shape, etc.), e.g. for the toner concentration or for a control threshold and the toner concentration thus regulated.
  • This toner concentration control in a developer station to be used in the intervals between the toner mark measurements can be carried out in a manner known per se.
  • the subsequent toner delivery is regulated in a different way over relatively large printing intervals (between the toner mark evaluation cycles).
  • the toner consumption can also be determined on the basis of the printed information, in particular by the total number of printed pixels. This determination can also be made depending on the contrast ratio set on the printing device, a certain transfer printing efficiency, the age of the toner / developer mixture, the type of toner and / or other influencing variables. The quantities of toner determined in this way can then be used to regulate the toner supply into the developer station from a toner reservoir.
  • the object is achieved in the intervals between the formation and measurement of the to- o co M to h- 1 cn ono CJi o cn rt to 3 ⁇ 2 co ⁇ ⁇ ⁇ o Hi N co to tx tr er ⁇ 3 ⁇ CQ DJ ⁇ ! t?
  • tolerances of a toner mark sensor used in the inking setting process and the photoconductor drum, operating temperature, etc. are largely compensated for during the setting process.
  • the third aspect of the invention also makes it possible to adjust the inking in a printing device during printing via one or a few values, for example via the BIAS tension of a developer roller.
  • the toner concentration is to be kept constant during printing via a toner concentration control, for example by means of the measures of the first or second aspect of the invention.
  • the toner marks are preferably scanned on the light-sensitive intermediate image carrier (photoconductor).
  • the light-sensitive intermediate image carrier photoconductor
  • a fourth aspect of the invention which is a further development of the aforementioned aspects of the invention, it is provided that in the course of a regulation at a first point in time a first toner mark with a particularly relatively large first area is scanned on the light-sensitive intermediate image carrier and the regulation of the toner concentration Adjust the basis of the scanning result until a second toner mark with a second area, which is in particular smaller than the area of the first toner mark, is scanned on the recording medium. Afterwards, further small toner marks can be scanned on the recording medium and co CO M PO h- 1
  • the interference can e.g. result from a different toner requirement of successive print images due to a different ratio of the printed and non-printed area of the carrier material.
  • the toner concentration control is automatically adapted to changes in process conditions.
  • changes in process conditions can e.g. occur due to aging processes of the material of the photoconductor, aging of the developer mixture, change in the triboelectricity and due to a changed toner throughput in the developer station.
  • the first controller, the first sensor arrangement, the developer unit and a toner delivery unit form a first control loop which serves as an auxiliary control loop or a follow-up control loop.
  • the second controller, the second sensor arrangement, the first controller, the toner delivery unit, the developer unit and the printer unit form a second control loop which serves as the main control loop or guide control loop.
  • the first and / or second controller after a PID Control algorithm works. It is thereby achieved that the control of the toner density of the toner image of the electrographic printing and / or copying device is realized with the aid of known control algorithms and that a cascade control structure is used. Good dynamic behavior of the control loop is achieved especially with cascade controls.
  • the two control loops in series, with the first controller as a coarse controller and the. second controller acts as a fine controller.
  • the use of P-controllers, PI-controllers, PD-controllers is also conceivable, whereby the controllers can be continuous controllers and discontinuous controllers.
  • the region of the toner image detected by the second sensor arrangement is located, i.e. the toner mark on the photoconductor material.
  • the toner mark is on a photoconductor drum. It is also advantageous not to re-print this toner mark on the carrier material by applying the toner mark to a point on the photoconductor drum that is outside the region of the photoconductor drum to be re-printed, by removing the toner mark from the photoconductor drum before the transfer or by the transfer printing is interrupted during the application of the toner mark by swiveling and stopping the paper transport. It is thereby achieved that the carrier material is not provided with disruptive printed images or that it is not necessary for parts of the carrier material to be output as waste.
  • a toner concentration control is carried out in the developer station with the aid of the first control loop and a toner mark control is carried out with the aid of the second control loop. It is furthermore advantageous to generate the toner marks in the electrographic process only at relatively large page intervals, for example only after a few thousand printed pages, during a second operating phase and scan. The toner mark control is thus carried out during this second operating phase.
  • the toner concentration control is carried out in the intermediate printing intervals, ie during a first operating phase. From the measured value determined by the toner mark (toner density, toner mark shape, etc.), a target value or a control threshold value for the toner concentration is determined during the second operating phase, with the aid of which the toner concentration is regulated.
  • This toner concentration control to be carried out in the first operating phase in the developer station can be carried out in a manner known per se.
  • the toner marks can thus be re-printed on carrier material when the toner mark regulation is carried out, without the printed images of the print jobs being impaired.
  • a particular advantage of the invention is that the toner mark can be designed to be very wide transversely to the transport direction and of any length in the transport direction. This toner mark can extend up to the entire width of the intermediate image carrier, e.g. up to the width of a photoconductor drum. As a result, the toner mark can be evaluated at several points, in particular according to the method described in WO-A-99/36834. The content of this publication is hereby incorporated into the present description.
  • the toner consumption can also be determined on the basis of the printed information, in particular by the total number of printed pixels. This determination can also take place as a function of the contrast ratio set on the printing device, a certain transfer printing efficiency, the age of the toner / developer mixture, the type of toner and / or other influencing variables. These quantities can then be used to regulate the supply of toner into the developer station from a toner supply container. It is also advantageous that the carrier material printed in the second operating phase is output locally separately from the carrier material printed in the first operating phase. This automatically separates the backing material to be processed from the waste.
  • the printing result is checked by detecting the intensity of the toner coverage of the toner mark.
  • a new setpoint for the toner concentration control is determined with the aid of a setpoint / actual value comparison carried out in the toner mark controller.
  • a correction value it is also possible for a correction value to be determined with the aid of the toner mark control, which serves to correct a predetermined target value of the toner concentration control. It is particularly advantageous to multiply the determined correction value by the preset current target value.
  • the toner supply to the developer station and the triboelectric charging of the developer mixture are regulated with the aid of the first controller output signal. This ensures that too much toner is not supplied to the developer mixture in the developer station, since if the toner content is too high, the triboelectric charging of the developer mixture is hindered.
  • the triboelectric charging of the developer mixture is decisive for the coloring of the latent printed image on the photoconductor material with toner.
  • a latent image arranged on a toner carrier is colored with toner with the aid of a developer station.
  • the developer station contains a developer mixture of toner and carrier with an adjustable proportion of toner.
  • a first sensor arrangement determines a value from a first predetermined area of a toner image as a measure of the intensity of the toner coverage and outputs a first sensor signal corresponding to the intensity.
  • a second sensor arrangement determines a value from a second predetermined area of the toner image as a measure of the intensity of the toner coverage and outputs a second sensor signal corresponding to the intensity.
  • the first sensor signal and a first setpoint are fed to a first controller, which forms a first controller output signal with the aid of a setpoint / actual value comparison.
  • the second sensor signal and a second setpoint are fed to a second controller, which forms a second controller output signal with the aid of a setpoint / actual value comparison.
  • the first setpoint is determined using the second controller output signal.
  • the toner supply to the developer station is regulated using the first controller output signal.
  • the second controller determines the first setpoint during a second operating phase and that the first controller forms a controller output signal during a first operating phase with the aid of the setpoint determined in the second operating phase. It is thus possible to use the setpoint of the first controller a toner mark is determined, which has been generated on the area of the photoconductor to be printed on the carrier material and / or on the carrier material.
  • the toner mark can be generated, for example, over the entire width of the carrier material.
  • measurement errors due to so-called edge effects when determining the optical toner density are excluded.
  • the setpoint or a correction value for adapting the setpoint can be precisely determined.
  • print jobs are then processed by the electrophotographic printing and / or copying device, a small toner mark, the intensity of which is generated on an area of the carrier material which is not to be processed further and / or on an unprinted area of the photoconductor the toner coverage is determined using the first sensor arrangement. It is thereby achieved that the print jobs processed during the first operating phase have a high print quality and that the toner marks necessary for the regulation are not visible on the areas of the carrier material which are used further.
  • the first setpoint is determined with the aid of the second controller output signal during a third operating phase.
  • this third operating phase several toner marks are generated one after the other, the optical toner density of which is detected with the aid of the first and / or second sensor arrangement.
  • the first and / or second sensor arrangement can scan each toner mark at several points.
  • the first setpoint is phase varies, the setpoint being determined at which sufficient toner coverage is just being achieved. This ensures that no more toner is used than is necessary for a high-quality print image.
  • the determined values of the sensor arrangements, the first setpoint and / or the second setpoint are stored in a memory area of the electrographic printing and / or copying device. After replacing the photoconductor, a toner mark is generated, from which the sensor arrangements again determine values and compare them with the stored values. At least one correction value is determined using the comparison results.
  • the sensor signal of the first sensor arrangement, the sensor sensitivity of the first sensor arrangement, the sensor signal of the second sensor arrangement, the sensor sensitivity of the second sensor arrangement, the first setpoint and / or the second setpoint are adapted by addition, subtraction and / or multiplication with the correction value.
  • a correction value is determined by comparing the newly determined values with the stored values.
  • the sensor signal of the first sensor arrangement, the sensor sensitivity of the first sensor arrangement, the sensor signal of the second sensor arrangement, the sensor sensitivity of the second sensor arrangement, the first setpoint and / or the second setpoint are adapted by addition, subtraction and / or multiplication with the correction value. It is thereby achieved that during maintenance work on the electrographic printing and / or copying device an automatic adaptation to changed properties of components of the electrographic printing and / or copying device takes place.
  • the adjustment of the regulation of the electrographic printing and / or copying device to the properties and / or characteristics of the components changed as a result of the maintenance work can be carried out in a separate third operating phase. Generating of several toner marks on the carrier material is possible in the third operating phase, the so-called maintenance and calibration operating phase.
  • a method with the features of claim 49 or 50 enables the control quality to be increased by chaining two controllers.
  • the interference can e.g. result from a different toner requirement of successive print images due to a different ratio of the printed and non-printed area of the carrier material.
  • the toner concentration control is automatically adapted to changes in process conditions.
  • changes in process conditions can e.g. due to aging processes of the material of the photoconductor, aging of the developer mixture, change in the triboelectricity e.g. due to changed toner throughput in the developer station.
  • FIG. 1 shows a schematic sectional illustration of an electrophotographic printing device
  • FIG. 2 electronic components of the printing device
  • FIG. 3 shows a flow chart for printing and producing a toner mark
  • Figure 4 shows a second electrographic printing device
  • Figure 5 is a timing diagram for an electrophotographic parameter
  • FIG. 6 shows a flow chart for two operating states
  • FIG. 7 shows a block diagram of a control principle of the fifth aspect of the invention.
  • FIG. 8 shows a block diagram of a control principle of a further embodiment of the invention.
  • FIG. 9 shows a diagram in which the time course of the activation of a toner mark and a toner concentration control as well as the activation of the printing process according to the aspect of the invention shown in FIG. 7 is shown.
  • FIG. 10 shows a diagram in which the time profile of a first toner mark control and a further toner mark control as well as the activation of the printing process according to the aspect of the invention shown in FIG. 8 is shown.
  • 11a to 11c show a flowchart for controlling and regulating a printing and / or copying device according to the invention
  • Figure 12 shows the interaction of different elements of the printing and / or copying device with the Control unit of the printing and / or copying device
  • Figure 13 are a part of a pressure side of the continuous paper with margin, followed by a 'leash toner mark is transfer-printed, and a section of a photoconductor, on the two large toner marks shown, and
  • control panel 14 to 17 the structure of control panel functions of the control panel of the printing and / or copying device and examples of displays of the control panel.
  • a printing device 1 for web-shaped recording media working according to the principle of electrophotography is shown schematically.
  • the web-shaped recording medium in the form of a paper web 2 is fed from a drive unit 3 with a motor-driven friction roller 19 in the direction Ai to a photoconductor drum 4.
  • the unit additionally contains movable swivel elements 15 with which the paper web 2 can be pressed against the surface of the photoconductor or can be lifted off the latter. For this purpose, they can be moved automatically with an electrical actuator 20, for example a stepping motor or lifting magnet.
  • Suitable swivel elements are known in the form of transfer printing rockers, for example from WO 97/17635 AI. They can be designed in particular like the rockers 40 and 44 shown in FIG. 5 of the WO publication, and can be pivotably mounted on axes in such a way that the paper web can be pivoted in and out length-neutral with respect to parts of the drive unit which are further away.
  • the content of WO 97/17635 AI is hereby also incorporated by reference into the present description.
  • the paper web 2 is printed in a transfer printing zone 5.
  • an intermediate toner image is applied to the via a driven photoconductor drum 4 by various coupled units, which intermediate image is printed on the paper web 2 in the transfer printing zone 5.
  • a first unit is a character generator 6, which contains a light emitting diode comb with individually controllable light elements and which can be constructed, for example, in accordance with WO-A-96/37862. This publication is hereby incorporated by reference into the present description.
  • the character generator 6 can be regulated in its light intensity by varying the control voltage or the control current.
  • An electronic controller controls the individual light emitting diodes in accordance with the image information to be printed.
  • a charging sensor 7 adjoins the exposure station 13, which measures the surface potential on the photoconductor drum 4 and emits a signal as a function thereof.
  • the image (charge image) generated on the photoconductor drum 4 depending on the character with the character generator 6 is colored with the aid of a developer station 8.
  • the developer station 8 contains a toner reservoir 9 for receiving toner and a metering device 10 in the form of a metering roller. Depending on the toner consumption, the metering roller 10 supplies toner to a mixing chamber 11. In the mixing chamber 11 there is a toner / developer mixture of ferromagnetic carrier particles and toner particles. The toner mixture is fed to a developer roller 12.
  • the developer roller 12 acts as a so-called magnetic brush roller and consists of a hollow roller with magnetic strips arranged therein.
  • the developer roller 12 transports the developer mixture to a development nip 13 between the photoconductor drum 4 and the developer roller 12. Excess developer mixture is transported back into the mixing chamber 11 via the developer roller 12.
  • the toner mark sensor 14 is an optoelectronic scanner, which can be designed, for example, as a reflection light barrier. It consists of a light source and a photo transistor as a receiver. The output signal of the phototransistor depends on the reflectance of the information applied to the photoconductor drum 4 and colored by the developer station. The sensor is used in particular to scan a toner mark which is used to determine the color saturation, i.e. the applied optical density of the toner mark serves. The wavelength of the reflection light barrier is selected so that the scanning light has no influence on the function of the photoconductor drum 4.
  • BIAS voltage An electrical voltage, the so-called BIAS voltage, is applied between the developer station 8 and the photoconductor drum.
  • the BIAS voltage can be used to control the toner transfer from the developer station 8 to the photoconductor drum 13 and thus the coloring. Further details of a BIAS voltage regulation are described in US Pat. No. 5,767,888, the content of which is hereby incorporated by reference into the present description.
  • the toner mark is started during a second operating phase when a test routine is called up or automatically, for example after 2000 printed pages.
  • the toner mark that is then generated is scanned and the test pattern is evaluated, for example with regard to color density and / or color saturation.
  • the paper web 2 is pivoted away from the photoconductor drum 4 so that it does not touch the surface of the photoconductor drum in the transfer printing zone 5.
  • the drive unit 3 or the paper web 2 is pressed against the photoconductor drum 4.
  • kenden pressure elements 15 are then pivoted away from the photoconductor drum 4.
  • a cleaning device 16 behind the transfer zone 5, with which residual toner, which has not been detached from the photoconductor drum 4 in the area of the transfer printing zone 5 or has been transferred onto the paper 2, is removed from the photoconductor drum 4.
  • the cleaning station 16 is constructed in the usual way and contains e.g. a wiping element 17, which wipes off the excess toner or the carrier particles from the photoconductor drum 4.
  • the cleaning process is supported by a corona device 18.
  • further corona devices are provided in the printing device in a manner known per se. This includes, for example, a charging corotron, which is provided between the cleaning device 16 and the character generator 6.
  • Exposure devices which serve to discharge the photoconductor drum 4 can also be arranged in the device. Further details on the electrophotographic process and the associated devices are described, for example, in EP 403 523 B1, the content of which is hereby incorporated into the present description by reference, as is the content of the corresponding patent in the U.S.A.
  • FIG. 2 shows a device controller 25 of the electrographic printer, which is connected to all electronic components of the various units of the device, so that the processes can be coordinated with one another.
  • the device control 25 is connected to a controller 26, in which print data to be printed is received and the signals of the character generator 6, which can be controlled at points, are converted into signals which can be controlled. These signals are transmitted to the controller 27 of the character generator.
  • the device controller 25 is connected to a controller 28 which controls electrophotographic parameters such as the voltages of corotron wires.
  • the to- scanning the photoconductor drum 4 co o [V> to ⁇ 1 ⁇ > cn o cn o cn o c ⁇
  • step Sla A first operating state is shown in the method steps Sla to S5a, in which print data are printed on the paper web 2.
  • step Sla it is checked whether print data is available. If this is not the case, the printing device switches to a stand-by state in which various units, such as the photoconductor drum, transfer printing corotron, the transport unit, etc., are set for low energy consumption.
  • the device controller 25 receives a signal from the controller 26 that print data is available, it activates the units involved, in step S3a the electrophotographically relevant units and in step S4a the transport unit 3.
  • the servomotor 20 is activated by which the paper web 2 is pivoted to the surface of the photoconductor drum 4.
  • the drive motor is activated, which sets the friction transport roller 19 in motion for transporting the paper web.
  • the print data to be output are then written via the character generator 6 onto the photoconductor drum 4 as an intermediate toner image, the intermediate toner image is applied onto the photoconductor drum in the developer nip 13 of the developer station 8 onto the photoconductor drum 4 and is printed onto the paper web 2 in the transfer printing zone 5.
  • the toner image thus re-printed is later fixed in a fixing device on the recording medium 2.
  • the toner concentration in the developer station 8 is controlled by a toner concentration control.
  • the sensor 21 permanently detects the toner concentration in the developer station 8 and maintains a constant toner-developer mixture in the mixing chamber 11 by appropriate subsequent conveying with the conveying device 10.
  • the amount of toner conveyed by the device 10 per unit of time by counting the re-printed, set pixels in the controller 26 and / or other variables determining the toner consumption, such as using the contrast setting of the image, the temperature of the photoconductor drum or the like to determine the amount of toner delivered.
  • the normal printing process is interrupted and the current development conditions are checked using a toner mark.
  • the paper web 2 in the transfer printing zone 5 is first pivoted away from the surface of the photoconductor drum 4 by means of the pressure elements 15. The paper transport is also stopped.
  • step S9a the value of the page counter is stored in a memory of the printer controller 25.
  • Steps S12a to S17a describe a second operating state in which a toner mark is applied to the photoconductor 4 is written and evaluated to modify the toner delivery control, which takes place during the transfer printing phase (S5a) in normal printing operation.
  • step Sl2a one or more toner marks are written onto the photoconductor drum 4 one after the other.
  • the toner marks can be generated during one revolution of the photoconductor drum or, alternatively, several toner marks over several revolutions of the photoconductor drum 4.
  • the toner marks are so wide that they enter the write area of the photoconductor drum, in which printing information is output during normal printing operation (step S5a) normally be printed on the paper web 2. If necessary, the toner mark can even extend across the entire width of the photoconductor drum 4. Toner marks generated in this way on the photoconductor drum 4 or the marks are scanned with the sensor 14 in step S13a and evaluated in the controller 25.
  • the evaluation can take place with regard to the generated toner density and / or with regard to the shape of the toner mark. Depending on the type of toner used (e.g. different colors), the toner mark or the toner marks can have different densities, shapes and / or dimensions.
  • a value is then derived from the values, which is compared with a control threshold value RS in step S14a. If the toner density value OD of the toner marks lies in the interval [RS- ⁇ , ..., RS + ⁇ ], the operating mode of the toner mark printing can be terminated in step S17a and the system can be switched back to the normal printing operating mode.
  • step S15a If, on the other hand, the toner density OD lies outside the interval [RS- ⁇ , ..., RS + ⁇ ], toner delivery is initiated in step S15a and a further toner mark is generated in step S12a.
  • This process (steps S12a to S15a) is repeated until the inking OD of the toner mark lies in the required interval.
  • at least one correction value is determined from the operating mode of the toner mark generation in step S16a, with which the regulation of the toner concentration in the normal printing phase (steps S S5a to S8a) is adjusted.
  • a control threshold value for the toner concentration is changed.
  • step S13a can also lead directly to step S16a and / or to step S17a.
  • the toner concentration control in the printing intervals which lie between the adjustment operating states in which toner marks are formed and evaluated can be carried out, for example, according to the methods described in US 4,468,112 A or US 5,387,965 A. The contents of which are hereby incorporated by reference into the present description.
  • a difference is formed from the measured toner density and the target value of the toner density, and the difference value is used to determine a new toner concentration target value or a threshold value for controlling the toner concentration.
  • a factor from the measured value for the toner density is used to change a toner concentration setpoint and / or a toner concentration control threshold.
  • the amount of toner conveyed into the developer station per unit of time can also be adapted in step S12a.
  • other parameters such as the sum of set (i.e. set or colored, especially black pixels), the temperature of the photoconductor drum or the set image contrast can also be taken into account for more precise control.
  • a further printing device is described in FIG. 4, in which in a first printing unit 150a at least one latent image is shown on a photograph by a first character generator 124a. conductor band 122a is generated. With a multiplicity of developer stations 126a, 126b,... 126e, which contain toners of different colors, one or more intermediate toner images are generated on the photoconductor belt 122a in the direction of movement B. Correspondingly, latent images and intermediate toner images of different colors are generated by a second character generator 138a and by a plurality of developer stations 140a to 140 in a second printing unit 152a on a second photoconductor belt 136 in the direction of movement D.
  • This printing device is described in WO-Al-00/34831. The content of these is also hereby incorporated by reference into the present description.
  • the intermediate toner images are transferred at a first transfer location 128a from the first photoconductor belt 122a to a first transfer belt 130a running in the direction C and accordingly at a third transfer location 142a from the second photoconductor belt 136 to a second transfer belt 144a which moves in the direction E.
  • the transfer belts 130a, 132 each collect the intermediate toner images of the different color separations and then print the full-color image at a second transfer station 132 or a fourth transfer station 146 on the web-shaped recording medium 114a on both sides, that is to say duplex.
  • the recording medium 114a which is driven by friction with transport rollers 116a, then passes through a fixing station 118a in the transport direction A for fixing the two toner images and is then cooled in a cooling device 120a.
  • an operating state is carried out in which a toner mark is generated by the character generators 124a and 138a and by at least one of the developer stations 126a to 126e and 140a to 140e on at least one photoconductor 1122a, 136.
  • the toner mark is then printed onto one of the transfer belts 130a, 144a, scanned there by one of the optoelectronic sensors 154, 156 and from the transfer belt removed without being reprinted on the paper web 114a.
  • the two transfer belts 130a and 144a can be lifted off the paper web 114a in the area of the transfer printing stations 132 and 146, so that transfer printing onto the paper 114a can be prevented.
  • the toner mark can also be scanned on the photoconductor belts 122a, 136 by corresponding sensors. Then either the transfer printing on the transfer belts 130a, 144a or the transfer printing on the paper web 114a is prevented.
  • correspondingly fast switching means are provided in the area of the transfer printing zones 132, 146 and / or 128a, 142a.
  • FIG. 5 a shows how a parameter, here the BIAS voltage on the photoconductor drum, is set in various operating states of the device in accordance with the third aspect of the invention.
  • the corresponding colorations are shown in FIG. 5b.
  • a toner mark is generated on the photoconductor drum.
  • the BIAS voltage on the photoconductor is set to the defined reference value U BIAS; r and then performed the measurement on the toner mark.
  • the BIAS voltage U BIAS can be set to predetermined reference values for generating and / or during the scanning of the toner mark.
  • these parameters are always set to the same reference values, the BIAS voltage, for example to U B ⁇ as, r , regardless of which contrast level is set in the control at the time of calibration.
  • the setting of the inking is then only dependent on the BIAS voltage, as long as the toner concentration in the developer station is constant.
  • the BIAS voltage U B ⁇ AS ⁇ is set (see FIG. 5a).
  • the BIAS voltage UBIAS, 2 • is set from time t 2
  • FIG. 6 shows the procedure described in FIG. 5 in accordance with the third aspect of the invention again in a flow chart.
  • a desired coloring is set in step S22a.
  • the pressure device and thus all units involved are switched to the MixUp operating state and (corresponding to step S27) various device parameters such as the. BIAS voltage set to predefined reference values.
  • the paper transport unit lifts the paper web from the photoconductor in order to prevent transfer printing (see step S 11a in FIG. 3a).
  • step S24 After successful adjustment of the setting parameters in the MixUp state, this state is exited and in step S24 it is checked whether new parameters are available for normal printing operation. If this is not the case, normal printing is continued with the parameters last set (eg degree of inking) (step S25a). It is then checked in step S26a whether a predetermined number of pages, for example 10,000 pages, has been printed since the last comparison (mix-up comparison). As an alternative to the number of pages, a time query can also be carried out during printing. If this is the case, the device parameters are reset to the specified values for the mix-up state (step S27a). If it turns out in step S26a that the specified number of pages has not yet been reached, the process continues. prints (return to step S25a) until the predetermined number of printed pages is reached.
  • step S24a If it emerges in step S24a that a • new contrast level was desired and entered by the operator (steps S28a and S29a), then the corresponding device parameters, in particular only the BIAS voltage, are corresponding to the new contrast level (coloring ) set.
  • FIG. 7 shows a block diagram of a first embodiment of the printing and / or copying device according to the invention.
  • a printing unit 40 is used during a second operating phase with the aid of the toner mark sensor 42, e.g. with the help of a reflex light barrier, the intensity of the coloring of this toner mark with toner, i.e. the optical toner density.
  • the toner mark sensor 42 outputs an output signal s2 corresponding to the optical toner density, which is normalized with the aid of a converter 44 to the input area of a toner mark regulator 46.
  • the converter 44 is connected to the toner mark regulator 46.
  • the normalized sensor signal is fed to an input of the toner mark controller 46 as the actual value x2.
  • Another input of the toner mark controller 46 is connected to a central controller 48 which supplies the toner mark controller 46 with a setpoint value w2 standardized to the input area of the toner mark controller 46.
  • the central controller 48 is connected to an operating panel 50, for example a touch screen.
  • the central control 48 determines the target value w2 from the contrast setting preset on the control panel 50.
  • the contrast setting can be preset via an input mask by an operator on the control panel 50. If such a setting is not made, • a preset standard value is used.
  • the toner mark controller 46 compares the actual value x3 with the target value w2, ie it performs a target value-actual value comparison and determines a controller output signal y2 using a PID control algorithm.
  • a developer station 52 there is a developer mixture of ferromagnetic carrier particles and toner particles.
  • the quantitative ratio of carrier particles and toner particles is determined by a toner concentration sensor 54.
  • the output signal sl of the toner concentration sensor 54 is fed to a converter 46 which is connected to an input of the toner concentration controller 58.
  • the converter 56 converts the output signal sl of the toner concentration sensor 54 into a signal xl adapted to the input area of the toner concentration controller 58.
  • the regulator output signal y2 of the toner mark regulator 46 is fed to a converter 60.
  • the converter 60 is connected to a further input of the toner concentration regulator 58.
  • the regulator output signal y2 of the toner mark regulator 46 is normalized with the aid of the converter 60 to the input region of the toner concentration regulator 58 and supplied to it as a setpoint value w1.
  • the toner concentration controller 58 carries out an actual setpoint comparison, the normalized signal xl of the toner concentration sensor 54 being supplied as the actual value and the normalized signal wl of the controller output signal of the toner mark controller 46 being supplied as the setpoint to the toner concentration controller 58. Based on the setpoint-actual value comparison, the toner concentration controller 58 forms a controller output signal yl with the aid of a PID control algorithm.
  • the toner concentration controller 58 is also connected to a control unit (not shown) of a toner delivery unit 62.
  • the controller output signal yl is fed to this control unit.
  • the toner conveying unit 62 supplies toner to the developer mixture in the developer station 52, whereby the quantity ratio of carrier particles to toner particles in the developer station 52 is changed. This change is in turn detected by the toner concentration sensor 54.
  • the changed toner supply also affects the coloring Exercise a latent print image of the printing unit 40 and thus affects the print image on a printed carrier material. This changed print image is detected in the second operating phase by the toner mark sensor 42 using the toner mark.
  • the changed toner supply is thus detected by the toner concentration sensor 54 and by the toner mark sensor 42, which are supplied to the toner concentration controller 58 and the toner mark controller 46 as changed actual values x1 and x2, respectively.
  • the toner concentration sensor 54 also detects the quantity ratio of carrier particles to toner particles in the developer station 52 during a first operating phase in which print jobs are being processed. As a result of different print images of the print jobs, the toner requirement can fluctuate greatly, whereby the quantity ratio of the carrier particles to toner particles also varies.
  • the amount of toner conveyed by the toner conveying unit 62 is regulated in such a way that the quantity ratio of carrier particles to toner particles in the developer station 52 is kept constant in accordance with the desired value w1. A uniform optical toner density of the printed image is thus guaranteed.
  • the coloring is checked using a generated toner mark with the aid of the toner mark sensor 42. If the optical toner density deviates from the predetermined target value w2, the toner mark controller 46 changes the output signal y2 as a function of this deviation, as a result of which the target value w1 of the toner concentration controller 48 is changed.
  • FIG. 8 shows a block diagram of a second embodiment of the printing and / or copying device according to the invention.
  • the basic elements shown are identical to the basic elements shown in the block diagram in FIG. The same elements have the same reference symbols.
  • the printing and / or copying device of the embodiment of the invention shown in FIG. 8 does not have a toner concentration sensor 54 in the developer station.
  • Two toner mark sensors 64, 42 are arranged in the printing unit 40, the toner mark sensor 42 in this embodiment having the same function as the toner mark sensor 42 in the embodiment of FIG. 7.
  • a toner mark is generated in the first operating phase on a region of the photoconductor drum that is not to be printed, a toner mark sensor 64 detecting the optical toner density of this toner mark.
  • the toner mark sensor 64 outputs an output signal corresponding to the optical toner density of this toner mark.
  • the toner mark sensor 64 is connected to the converter 56, which normalizes the output signal of the toner mark sensor 64 to the input region of the controller 58.
  • the controller 58 functions as a toner mark controller and is referred to as a TM controller (1st controller).
  • the controller 46 is a toner mark controller and is referred to in this exemplary embodiment as a TM controller (2nd controller).
  • the mode of operation is identical to that of the toner mark regulator 46 according to the exemplary embodiment in FIG. 7.
  • a small toner mark is generated on an area of the carrier material that is not to be processed further.
  • This small toner mark has, for example, the dimensions of 12.7 mm in the transport direction of the carrier material and 3.4 mm transversely to the transport direction of the carrier material.
  • This small toner brand is also known as an online toner brand because it is generated at regular intervals during the processing of print jobs. In front- It is a good idea, for example, to create and evaluate an online toner brand with each print page to be generated.
  • the toner mark controller 58 also carries out a setpoint-actual value comparison and outputs a controller output signal y1.
  • a large toner mark is generated on the area of the photoconductor to be printed, which is e.g. Is 12.7 mm long and 6.8 mm across the direction of movement of the photoconductor drum.
  • the toner mark sensor 42 is used to make a more precise determination of the optical toner density, since a possible falsification of the toner mark signal, e.g. due to the edge effect is avoided. If the transport speed of the carrier material is increased, the toner mark can be extended as required and, if necessary, broadened.
  • two toner marks with different toner colors can also be generated in the second operating phase, one mark being detected by the toner mark sensor 64 and one toner mark being detected by the toner mark sensor 42. These signals are then fed directly to the central controller 48, which compares the determined optical toner densities with the preset target value w2 and directly supplies the toner mark controller 58 with a new target value w1. To determine the setpoint wl by the central controller 48 or to regulate the setpoint wl with the aid of the toner mark regulator 46, a plurality of toner marks, for example twenty toner marks, can also be generated in succession during the second operating phase.
  • the controllers 46, 58 can be integrated, for example, as software controllers in the central controller 48.
  • FIG. 9 shows a diagram which shows the time course of the activated control and the printing process of the first embodiment of the invention.
  • the diagram shows that during the normal printing process, ie during the first phase of operation when the printer is processing print jobs, the toner concentration control is active.
  • the first operating phase is ended, ie the processing of print jobs is stopped and the printer is in a second operating phase.
  • toner marks are generated, at which point the toner concentration control is deactivated and only the toner mark control is activated.
  • the toner mark and the toner concentration control are activated simultaneously during the second operating phase.
  • a predetermined number of toner marks are generated in succession.
  • the toner mark controller 46 uses the optical print density to determine a new target value for the toner concentration controller 58.
  • the toner marks can only be produced on the photoconductor or can be re-printed on the carrier material. When transferring the toner marks onto the carrier material, it makes sense to output the carrier material provided with the toner marks in a separate output slot of the printer in order to prevent mixing with the printed pages of processed print jobs.
  • FIG. 10 shows a diagram which shows the time course of the activated control and the printing process of the second embodiment of the invention.
  • the toner mark regulator 58 is activated.
  • the toner mark controller 58 evaluates small toner marks that have been generated in a non-printable area of the photoconductor or that have been printed on a part of the carrier material that cannot be processed further.
  • the second toner mark regulator is 46 disabled.
  • the first operating phase is ended, ie the processing of print jobs is interrupted. Large toner marks are generated during this second operating phase, the optical toner density of which is determined with the aid of the toner mark sensor 42.
  • the toner mark regulator 58 for evaluating the small toner marks is deactivated and the toner mark regulator 46 for evaluating the large toner marks is activated.
  • the toner mark regulator 58 and the toner mark regulator 46 are active simultaneously during the second operating phase.
  • the second operating phase has ended.
  • the printer is again in the first operating phase and processes print jobs.
  • the second operating phase can also only be ended when a satisfactory result of the optical toner density of the generated toner mark has been reached and thus a further adjustment of the target value is not necessary. This means that the first and second operating phases alternate during printer operation. A total of five cycles are shown in the diagrams of FIGS. 9 and 10, in which the first and second operating phases alternate.
  • FIGS. 11a to 11c show a flow chart of a printing and / or copying device according to the invention.
  • step S10 the sequence is started, for example after the printer has been switched on.
  • step S12 it is then checked whether an operator has entered in step S14 on a control panel of the printer that an exchange of the photoconductor has taken place. If this is not the case, it is checked in step S16 whether an operator in step S18 co o IV) IV ) ⁇ >> c ⁇ o cn o c ⁇ o c ⁇
  • fTK and the temperature value T are stored in a memory area.
  • step S52 It is then checked in step S52 whether an entry has been made in step S54 on the control panel of the printing and / or copying device that the developer mixture has been exchanged. If it is determined in step S52 that the mixture has been exchanged, standard values for the toner concentration setpoint TKmin and for the correction factor fTK are read out from a memory area in step S55. If there has been no exchange of the developer mixture, the setpoint TKmin (Sp.) Determined in step S48 and stored in step S50 is read out in step S56 and used as the current setpoint TKmin.
  • step S58 The current toner concentration is then measured in step S58. Furthermore, in step S58, the change in the toner concentration dTK is determined from the measured value and a stored value of the toner concentration. The change in the toner concentration dTK is a measure of the activation, ie the operational condition, of the developer mixture.
  • step S60 it is checked whether the difference between the measured and the stored toner concentration value determined in step S58 is sufficiently small. If this is not the case, the mixture is activated in step S61, for example by feeding toner into the developer station. Steps S58, S60 and S ⁇ 1 are repeated until a sufficiently small difference has been found in step S60, so that sufficient activation of the developer mixture can be assumed.
  • the time from switching on the printing and / or copying device to this point in time in which step S60 is processed can also be determined. With a sufficiently long period of time, sufficient activation of the developer mixture can also be assumed. If the developer mixture is sufficiently activated, the toner concentration TK is measured in step S62 and compared in step S64 with a maximum value of the toner concentration TKmax read from a memory area in step S66. If the measured toner concentration TK is greater than the maximum permissible toner concentration TKmax, an error message is issued in step S68 that the maximum value TKmax of the permissible toner concentration has been exceeded, and then an emergency stop of the printing and / or copying device is carried out in step S70. All units of the printing and / or copying device are thus switched off.
  • step S72 the sequence is ended after the emergency stop carried out in step S70.
  • the developer mixture must be replaced by appropriately trained maintenance personnel or the high toner concentration in the developer mixture must be eliminated in some other way.
  • step S74 the measured value TK of the toner concentration is compared with a toner concentration setpoint TKmin read from a memory area in step S76. This toner concentration setpoint TKmin read from the memory area was determined in steps S22 to S50. If the measured toner concentration value TK in step S74 is greater than the desired toner concentration value TKmin, then in step S80 the current number of printed pages is compared with a preset value.
  • step S74 If the measured toner concentration TK in step S74 is not greater than the target toner concentration value, toner delivery is activated for a predetermined time in step S78, so that toner particles are fed into the developer unit. It is then checked in step S80 whether the number of printed pages that have been generated since the generation and evaluation of the last toner mark are greater than a preset value that specifies the number of printed pages between the generation of two toner marks. This preset value is read out, for example, from a memory area in step S82. If the number of printed pages is smaller than the predetermined value, the toner delivery is activated in step S84 for a further predetermined time.
  • step S62 The toner concentration is then evaluated again in step S62, whereupon steps S62 to S80 are repeated until step S80 determines that the number of printed pages matches the preset number. If this is the case, then a toner mark is subsequently produced on the photoconductor drum, from which the optical toner density TM is determined in step S86.
  • the print job to be processed is interrupted to generate and evaluate the toner mark.
  • step S88 it is then checked whether the measured value TM of the optical toner density is greater than an im
  • Step S90 setpoint value TMmax read from a memory area for the maximum optical toner density to be achieved. If the measured value TM is greater than the maximum toner density (TMmax) to be achieved, the value fTK is overwritten with the negative amount of the value fTK in step S92.
  • step S94 If the measured optical toner density value TM in step S88 is not greater than the predetermined maximum value TMmax of the optical toner density, it is checked in step S94 whether the measured value TM of the optical toner density is smaller than a predetermined minimum value TMmin of the optical toner density. For this purpose, the minimum value TMmin of the optical toner density is read out of a memory area in step S9 ⁇ . If the measured value TM of the optical toner density is smaller than the predetermined minimum value of the optical toner density, the value fTK is overwritten with the positive amount of the value dTK in step S98.
  • step S20 After the value fTK has been overwritten in step S92 or step S98, that is to say that the value fTK newly determined in step S92 or S98 has been stored in the same memory area in which the previously current value fTK was previously stored, the procedure in step S20 continued. Because the setpoint for the toner concentration control TKmin is formed in step S48 from the old setpoint of the toner concentration control and the value fTK, the setpoint TKmin is adjusted. Thus, the im
  • Step S86 measured optical toner density in steps S88 to S98 determined a correction factor fTK with which the target value TKmin is adjusted for the toner concentration control.
  • an offset value can also be determined, to which the previous target value TKmin for the toner concentration control is added.
  • other parameters and influencing variables such as the temperature of the photoconductor drum, the discharge of the developer mixture or the air humidity in the developer station are taken into account.
  • these parameters can also be taken into account when forming the correction factor.
  • step S88 It was determined in step S88 that the measured value TM of the optical toner density does not exceed the maximum value TMmax of the optical toner density, and it was also determined in step S94 that the measured value TM of the optical toner density does not fall below a minimum value TMmin of the optical toner density , the measured optical toner density TM and the value of the temperature T are stored in a storage area in step S100. After these values TM, T have been stored in step S94 and after resetting the number of times since generation of the last to- If the printed pages are generated in step S102, the control is continued in step S62.
  • FIG. 12 shows a block diagram of a control unit 70 and important elements of the components necessary for regulating and controlling the printing and / or copying device according to the invention.
  • a temperature sensor 72, a toner mark sensor 74 and a toner concentration sensor 76 are connected to the control unit 70. These sensors 72, 74, 76 transmit measured values to the control unit 70.
  • the temperature sensor 72 detects the temperature of the photoconductor 78, e.g. a photoconductor drum.
  • the toner mark sensor 74 detects the optical toner density of a predetermined area of the photoconductor 78.
  • the toner concentration sensor 76 detects the toner concentration of the developer mixture in a developer unit 88.
  • control unit 70 is connected to memory areas 80, 82, default values and standard parameters being preset in the memory area 80 are stored and in the memory area 82 are stored measured values and limit values which are determined during the printing process.
  • the memory areas 80 and 82 can be overwritten by the control unit 70 with new values.
  • the control unit 70 is also connected to a control panel 84.
  • the control panel 84 serves as a human-machine interface with an operator of the printing and / or copying device. With the help of the control panel 84, an operator can, for example, change the standard values stored in the memory area 80. For this purpose, the operator enters a new value for the parameter to be changed, the control unit 70 overwriting the part of the memory area 80 with the new value in which the old value is stored.
  • the control unit 70 is also connected to a metering device 86 for the toner supply. Such a metering device 86 conveys toner particles from a toner reservoir into the developer unit 88, so that the developer mixture is enriched with toner particles.
  • FIG. 13 shows a section of a printed page 90 and a section of a photoconductor 92.
  • a reprinted toner mark 94 is reprinted outside of a print area 96 on the print page 90.
  • This reprinted toner mark 94 is located in an area in which there are also transport holes, one of which is designated 98.
  • the area with the transport holes 98 and the toner mark 94 is separated from the print area 96 during further processing of the printed page.
  • the reprinted toner mark 94 is primarily limited in its width on the one hand by the print area 96 and on the other hand by the holes 98.
  • Typical dimensions of such a toner mark are a width of 3.4 mm transversely to the transport direction of the paper in the printer and a length of 12.7 mm longitudinally to the transport direction of the paper in the printer. This small, reprinted toner mark is typically generated on each print page 90 during a first operating phase.
  • two further toner marks 100, 102 are produced, which have a width of 6.8 mm transversely to the transport direction of the paper and also have a length of 12.7 mm lengthwise to the paper direction like the overprinted small toner mark.
  • the toner mark 102 is in the same track as the small toner mark when viewed in the transport direction of the paper. This is advantageous since the small toner mark 94 and the large toner mark 102 can be detected by the same toner mark sensor on the photoconductor 96 or after the transfer printing by the same toner mark sensor on the print page 90.
  • the small toner mark 94 In the case of small toner marks, such as, for example, the small toner mark 94, it is possible that reliable information about the optical toner density of larger printed areas is not possible due to edge effects that occur. It therefore makes sense to generate and evaluate the toner marks 100 and 102 during the second operating phase.
  • the toner mark 100 is not colored with toner as much as the toner mark 102.
  • Through the evaluation of these two differently colored large toner marks 100, 102 it is possible to better adapt the developer mixture. Above all, this makes it possible to recognize in advance a possible overtoning of the developer mixture due to an excessively high optical toner density of the toner mark 100.
  • all three toner marks one after the other in the same track 104 in the transport direction. All three toner marks can thus be detected by the same toner mark sensor.
  • the toner marks 100 and 102 are arranged in different tracks 104, 106, at least one toner mark sensor must be arranged in the printing and / or copying device for each of these horizontal planes.
  • a first toner mark control takes place during the first operating phase.
  • the optical toner density of the toner mark 94 is recorded and compared with a target value. If the optical toner density is lower than the target value, toner is fed into the developer unit and the toner mixture is enriched with toner. If the measured value of the optical toner density is larger than the target value, i.e. if the toner mark is too strongly colored with toner, the supply of toner into the developer station is stopped, so that toner is removed from the developer station by the printing process, as a result of which the developer mixture is emaciated.
  • the first operating phase is ended, ie no further print jobs are processed and the second operating phase begins, in which large toner marks 100, 102 are generated and evaluated.
  • the optical toner density of these large toner marks is sensed by toner mark sensors and when different colors are intended Toner marks compared to a target value each.
  • the setpoint for the toner mark control is corrected during the first operating phase.
  • a toner concentration sensor determines the toner concentration of the developer mixture of the developer unit, which is compared with a predetermined target value.
  • the toner marks 100 and 102 continue to be generated and the optical toner density of these toner marks is measured and evaluated.
  • a correction value is determined by which the target value for the toner concentration control is multiplied.
  • toner mark sensor After changing the toner mark sensor, it is possible to generate toner marks by an input on the control panel for adjusting and calibrating the toner mark sensor. It is also conceivable to simultaneously detect the toner concentration of the developer mixture of the developer unit and the optical toner density of the toner mark 94 during the first operating phase. This means that there are even more possibilities to carry out an exact regulation of the optical toner density of the print image and to always obtain an optimal print image.
  • FIG. 14 shows a number of display images with selection fields which can be displayed on the control panel of the printing and / or copying device.
  • the control panel contains a touchscreen with a display unit and a touch-sensitive surface of this display unit. An operator can thus function by touching areas of the display unit. Activate those assigned to the respective display area.
  • the selectable function of such a picture element 112, 114, 116 means that such a picture element is also referred to as a button.
  • the buttons 112, 114, 116 of the display image 110 represent selection options for a main menu of the printing and / or copying device.
  • buttons 112, 114, 116 When a button 112, 114, 116 is touched, an operator selects a function or a further display image 118, 128 in which further functions and / or submenus can be selected. If an operator touches the button 112 "Basic Unit", the display field 118 with the buttons 120, 122, 124 and 126 is selected.
  • the display images 110, 118 and 128 can also contain image elements which have no functions stored and which only serve to inform the operator. Such picture elements can contain, for example, text that designates the respective menu.
  • button 126 "Print density control" When button 126 "Print density control" is activated, an operator selects another submenu for setting the toner density control. As a result, the display image 128 is displayed on the display unit of the control panel.
  • the display image 128 contains buttons 130, 132, 134, 136, 138, by means of which further functions can be selected. If an operator selects the button 134 "Numerical representation", all measured, calculated and preset values relevant for the regulation of the optical toner density are displayed as current numerical values. These values are constantly updated so that the operator can follow the control behavior based on these numerical values during the printing process.
  • the variables relevant for the regulation of the optical toner density are displayed as continuous graphs in the so-called roll mode.
  • the toner concentration measurement values, the measurement values of the optical toner density of the toner marks, the temperature of the photoconductor drum and the respective target values of the control are displayed.
  • the graphs are displayed in the respective color of the toner.
  • the display field 128 contains buttons 130, 13 ' 2, each of which activate a further submenu in which functions for setting and monitoring the pressure density control are arranged.
  • a submenu can be selected in which setting options for a pressure density control of a first paper web, the web A, can be selected with the aid of further buttons.
  • Such a submenu can also be selected for a second paper web, web B.
  • the button 132 is not shown.
  • the submenu shown in the display image 128 can be exited, whereupon the display field 118 is displayed again.
  • FIG. 15 shows a display image 140 which is shown on the display unit of the control panel after the button 130 "Settings path A" of the display image 128 has been selected.
  • the image element 142 gives the operator the information that the setting options of the submenu shown in the image 140 relate to the paper web A, and that the print images to be printed on the paper web A are printed in the toner color black.
  • a button 144 activates toner delivery that is independent of the toner density control. After pressing the button 144 "Manual toner delivery", the metering device, which delivers toner from a storage container into the developer station, is activated for 6 x 2 seconds. During this manual toner delivery, the background color of this button 144 changes from white to red. During this activation time, the operator cannot select further buttons 146, 148, 150, 152 of this submenu. These buttons are locked during this time.
  • a button 146 "Measure parameters" is used, for example, after setting the optical density by dimensioning. to determine new setpoints for the toner concentration and for the toner mark control, which are used for the further control of the ' optical toner density ', gladly or by manual toner conveyance on the basis of the current values of the toner concentration and the optical density determined by the toner mark sensor. To do this, a printing procedure must be started in which toner marks are generated. During such a calibration process, the background color of this button 146 changes from white to green until the calibration process is complete.
  • a button 148 can be used to select a display image for setting a number of interleaves. This number of interleaves specifies the number of printed pages that are printed during the first operating phase before the first operating phase ends automatically and the second operating phase is started. Creating then effected a 'toner mark 100, 102 and detecting the optical density of toner in the second operating phase of the toner mark 100, 102nd
  • a further display image, not shown, can be selected with the button 150, in which the activated control type can be selected.
  • a combined toner concentration and toner mark control is preset as standard. However, e.g. in the event of a defective toner mark sensor, the toner mark control is deactivated in order to be able to continue processing print jobs. Even if the toner concentration sensor is defective, it is possible to deactivate the toner concentration control and carry out the replenishment of toner using the toner mark control.
  • the button 152 is used to exit the submenu. After pressing the button 152, the display image 128 is displayed again.
  • FIG. 16 shows further display images that can be displayed on the display unit of the control panel.
  • the display image 154 appears when the printer is ready for operation.
  • the display image 154 contains a picture element with text which prompts the operator to start the printer using the "Ready” button 160.
  • the button 158 By pressing the button 158, the operator can leave this display and return to the menu shown in the display image 140.
  • the operator is shown the display image 170 after selecting the button 146 "Measure parameters", in which the operator is informed with the aid of the image element 172, which contains the text, that the parameters is only possible when the printing and / or copying device is ready for operation.
  • the button 174 the operator can leave this display and return to the higher-level menu.
  • the display image 162 is displayed after the successful completion of the measuring process, whereby the operator is informed of the successful completion of the measuring process.
  • button 164 the operator confirms that he is aware of this message.
  • the display image 140 with the higher-level menu is then automatically displayed.
  • the display image 166 is displayed on the display unit of the control panel. This display image informs the operator that the calibration process has been canceled and indicates possible causes of the error.
  • the button 168 the operator confirms that he has become aware of this message, whereupon the button 164 automatically returns to the higher-level menu.
  • FIG. 17 shows a further display image 180 for presetting the contrast.
  • the contrast can be preset by an operator.
  • Toner delivery unit (dosing device) sl, s2 sensor values xl, x2 actual values wl, w2 setpoints yl, y2 controller output signals
  • control panel touchscreen
  • 110, 118, 128, 140, 154, 170, 162, 166, 180 display images to be displayed on the display unit of the control panel
  • buttons 174, 188, 190 buttons

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

Abstract

Procédé de régulation d'un processus électrographique d'impression ou de photocopie selon lequel des informations à imprimer sont produites sous forme d'image intermédiaire de toner sur un support (4, 122a, 130a, 136, 144a) d'image intermédiaire, puis transférées dans une zone (5, 132, 146) de report, d'une surface (130a, 144a) de report sur un support (2, 114a) d'impression. Une marque de toner est produite sur un support (4, 130a, 144a) d'image intermédiaire électrographique, ladite marque de toner est palpée tout au moins partiellement sur le support (4, 122a, 136) d'image intermédiaire et finalement éliminée dudit support (4, 122a, 136). La concentration de toner est régulée dans une station de développement (8) sur la base de la valeur mesurée. Le transfert de l'image intermédiaire de la surface (130a, 144a) de report sur le support (2, 114a) d'impression est au moins partiellement empêché dans le laps de temps séparant la production de la marque de toner et son élimination. Le dispositif présente donc deux états de fonctionnement. Dans le premier état, des valeurs de régulation de la concentration de toner sont déterminées et dans le deuxième état, l'impression a lieu. Tandis que dans le premier état de fonctionnement, des paramètres électrographiques sont réglés pour répondre aux exigences de l'utilisateur, par exemple le potentiel de charge d'un photoconducteur ou d'un cylindre de développement pour opérer des réglages de contraste répondant aux exigences de l'utilisateur, dans le premier état de fonctionnement, ces paramètres sont automatiquement réglés, à l'aide d'une commande, sur des valeurs prédéterminées en fonction desquelles est effectuée la régulation de la densité de toner.
EP01927648A 2000-02-04 2001-02-05 Procede et dispositif de regulation de la concentration de toner dans un processus electrographique Withdrawn EP1254559A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE10004868 2000-02-04
DE10004868 2000-02-04
DE10046946 2000-09-21
DE10046946 2000-09-21
PCT/EP2001/001224 WO2001058135A2 (fr) 2000-02-04 2001-02-05 Procede et dispositif de regulation de la concentration de toner dans un processus electrographique

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EP1254559A2 true EP1254559A2 (fr) 2002-11-06

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EP (1) EP1254559A2 (fr)
WO (1) WO2001058135A2 (fr)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0740221B1 (fr) * 1995-04-26 2001-10-10 Canon Kabushiki Kaisha Appareil de formation d'images et élément de transfert intermédiaire
JP3589270B2 (ja) * 1996-10-21 2004-11-17 セイコーエプソン株式会社 画像形成方法
JPH10274891A (ja) * 1997-03-31 1998-10-13 Ricoh Co Ltd 画像形成装置
CA2316162C (fr) * 1998-01-16 2007-09-04 Oce Printing Systems Gmbh Dispositif et procede d'impression ou de photocopie, une marque de toner etant detectee au niveau d'au moins deux points de mesure
DE19900164A1 (de) * 1999-01-05 2000-07-27 Oce Printing Systems Gmbh Verfahren und Einrichtung zur Regelung der Tonerkonzentration in einem elektrografischen Prozess

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0158135A3 *

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WO2001058135A3 (fr) 2001-12-20

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