JP2006267972A - Image formation apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct a control system by accurately estimating the amount of wear of a photoreceptor. <P>SOLUTION: A driving torque measuring part 17 for measuring a driving torque is arranged between a photoreceptor 10 and a photoreceptor rotary driving part 20 for driving the photoreceptor 10, and the driving torque of the photoreceptor 10 is measured with every certain time interval. Which section of a driving torque waveform should be used is preliminarily determined under setting conditions (the maximum value, average value, minimum value or the like), and charge acting on the photoreceptor 10 is calculated. The amount of the wear of the photoreceptor of the measurement interval is calculated from the calculated charge and the rotary frequency increment of the photoreceptor with the measurement interval. The film thickness of the photoreceptor 10 is calculated from the cumulative value of the calculated amount of wear, and charging conditions, exposure conditions and development conditions are corrected by using the calculated film thickness as a standard. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus, and adjusts a control system of an image forming apparatus main body by determining a wear amount of a photoreceptor.

  In an electrophotographic image forming apparatus such as a copying machine, the surface of the photoreceptor is worn because a charger, a developer, a cleaning blade, a sheet, and the like come into contact with the surface of the photoreceptor. There is a problem in that the image density changes due to changes in the light attenuation characteristics and development characteristics of the photoreceptor due to this wear.

  In order to cope with such a problem, Patent Document 1 arranges a film thickness measuring unit having an eddy current generator, and measures the film thickness by measuring the magnitude of the eddy current in contact with the photoreceptor. Has proposed. However, there is a problem that the photoconductor is scratched by the contact of the film thickness measuring unit.

  Patent Document 2 proposes to detect the lifetime of the photoreceptor by calculating the damage index of the photoreceptor from the voltage application conditions and the application time of the contact charger. However, this proposal does not take into account the effects of the cleaning blade and the paper type, and thus cannot deal with the problem of wear resulting therefrom.

Japanese Patent Application Laid-Open No. 2004-133830 proposes to calculate the abrasion amount of the photosensitive member from the predetermined amount of abrasion per rotation number of the photosensitive member and the photosensitive member rotation number. However, this proposal cannot take into account the effects of paper.
JP-A-8-95433 JP 10-39691 A JP 2002-244368 A

  The present invention has been made in consideration of the above circumstances, and accurately determines the amount of wear on the surface of the photoconductor, reflecting the effect of the members, recording materials, etc. that contact the surface of the photoconductor without leaving an image. It is an object to enable various controls of the forming apparatus and error notification.

  In the configuration example of the present invention, in order to achieve the above-mentioned object, the charged potential of the photoconductor is adjusted by providing a photoconductor wear amount predicting unit. The photoconductor wear amount prediction means predicts the wear amount by measuring the torque of the photoconductor.

  In addition, when the result of exceeding the preset maximum and minimum values is obtained for the torque measurement result of the photosensitive member, or the preset maximum and minimum values are exceeded. If the number of results obtained is equal to or greater than the set number, it may be determined that a cleaning failure or the like has occurred, and processing such as displaying an error on the display device or reporting the error to an engineer may be performed.

  Since the loads of all the members in contact with the photosensitive member are obtained by measuring the torque of the photosensitive member, the wear amount of the photosensitive member can be accurately predicted. A good image can be formed by correcting and controlling the potential condition and the development condition based on the predicted film thickness of the photoreceptor.

  Specifically, a driving torque measuring device for measuring the driving torque of the photosensitive member is disposed between the photosensitive member and the driving device, and the transition of the photosensitive member driving torque is measured at certain time intervals. The representative value of the driving torque is obtained from the transition of the driving torque, and the wear amount of the photosensitive member is predicted from the representative value of the driving torque and the number of rotations of the photosensitive member at the measurement interval. A torque measuring device may be mounted inside the photoconductor driving device.

  Further, the present invention will be described.

  According to one aspect of the present invention, in order to achieve the above-mentioned object, an image forming apparatus that forms an image by rotating, driving, and charging, exposing, developing, and transferring in association with the photoconductor: Torque measuring means for measuring the driving torque of the photoconductor; rotation amount measuring means for measuring the rotation amount of the photoconductor; measured values of the torque measuring means; measured values of the rotation amount measuring means; Wear amount predicting means for predicting the wear amount; and control system correcting means for controlling the control amount of image formation based on the predicted wear amount are provided.

  In this configuration, the amount of wear can be accurately grasped by reflecting the addition of various members to the photoconductor based on the measured value of the drive torque, and the control error caused by the wear can be eliminated. .

  The control system correction means corrects the target value of the charging potential or corrects the output level of the laser output to make the image density appropriate.

  Also, when the measured value of the torque measuring means exceeds at least one limit of the set maximum value and the set minimum value, or the measured value of the torque measuring means exceeds at least one limit of the set maximum value and the set minimum value. An error detection means may be further provided for detecting an error when the number of times exceeds the set number.

  In this way, it is possible to display a warning such as defective cleaning. In addition, a maintenance request can be notified to the maintenance staff.

  For example, the wear amount estimation means calculates A × ΔR × t (A is a constant) from the rotation increment ΔR of the photosensitive member and the corresponding measured value t of the driving torque for each measurement period, and calculates the calculated value. Cumulatively determines the amount of wear.

  As the measured value of the driving torque, any one of the maximum value, the minimum value, and the average value of the measurement section can be used, and a means for setting which one to employ may be provided.

  The present invention can be realized not only as an apparatus or a system but also as a method. Of course, a part of the invention can be configured as software. Of course, a software product used for causing a computer to execute such software is also included in the technical scope of the present invention.

  The above and other aspects of the present invention are set forth in the appended claims and will be described in detail below using examples.

  According to the present invention, it is possible to calculate the load affecting the photosensitive member from the driving torque of the photosensitive member. From this load and the number of rotations of the photoconductor, the wear amount of the photoconductor can be estimated sequentially. The image formation control system can be corrected from the estimated wear amount.

  Examples of the present invention will be described below.

  FIG. 1 shows an image forming apparatus according to an embodiment of the present invention. In this example, only one image forming portion is shown, but a plurality of image forming portions may be provided in accordance with the color image. Further, in the drawing, the portion related to the present invention is shown in a more simplified manner and the fixing unit or the like is not shown, but it is needless to say that it can be provided as appropriate.

  In FIG. 1, an image forming apparatus 100 includes a photoconductor 10, a charging unit 11, an exposure unit 12, a developing unit 13, a transfer unit 14, a cleaning unit 15, a paper transport mechanism 16, a drive torque measuring unit 17, and a wear amount estimating unit 18. Etc. are configured. The photoconductor 10, the charging unit 11, the exposure unit 12, the developing unit 13, the transfer unit 14, the cleaning unit 15, and the paper transport mechanism 16 are ordinary electrophotographic systems. The photosensitive member 10, the charging roll of the charging unit 11, the developing roll of the developing unit 13, and the transfer roll of the transfer unit 14 are rotated as indicated by arrows. As is well known, the surface of the photoreceptor 10 is charged to a predetermined potential using the charging unit 11, the surface of the photoreceptor 10 is exposed by the exposure unit 12 to form a latent image, and the toner image is developed in the developing unit 13. In the transfer unit 14, the toner image is transferred to a recording medium (not shown). The recording medium carrying the toner image is fixed by a fixing unit (not shown).

  The drive torque measuring unit 17 measures the rotational torque of the photoconductor 10. This will be further described with reference to FIG. The wear amount estimation unit 18 estimates the wear amount of the surface of the photoreceptor 10 based on the measurement value of the drive torque measurement unit 17, and corrects the target value of the charging potential of the charging unit 11 based on the estimated value, The output level of the laser diode of the exposure unit 12 is corrected. As a result, the density of the formed image is controlled to an appropriate value within a certain range regardless of the wear of the surface of the photoreceptor 10.

  FIG. 2 shows a configuration example of the wear amount estimation unit 18 together with examples of the photoconductor 10, the photoconductor rotation drive unit 20, and the drive torque measurement unit 17. In this figure, the photoconductor 10 is a photoconductor rotation drive unit. 20 is rotated by a drive torque measuring unit 17 (shown by an arrow in FIG. 1). The photoreceptor rotation driving unit 20 also includes a transmission system. The photosensitive member rotation drive unit 20 itself may be configured to include the drive torque measurement unit 17. The drive torque measuring unit 17 measures the torque applied to the photoconductor 10 from the photoconductor rotation drive unit 20.

  The wear amount estimation unit 18 estimates wear on the surface of the photoconductor 10 and supplies a correction amount to the image formation control portion, and also performs error detection. The signal processing unit 30 and the wear amount calculation unit 31 are also provided. , A target value correction amount calculation unit 32, an error detection unit 33, a photoconductor rotation amount measurement unit 34, and the like. The correction amount is supplied to, for example, the potential controller 11A of the charging unit 11 to adjust the target charging potential.

  The signal processing unit 30 measures the transition of the torque measurement value at predetermined time intervals and supplies the representative value to the wear amount calculation unit 31. Further, the photoconductor rotation amount measuring unit 34 measures a rotation increment for each predetermined time interval. The wear amount calculation unit 31 calculates the wear amount based on the torque measurement value and the rotation increment measurement value. The wear amount at each time interval is given by A × t × ΔR, and this is accumulated to calculate the total wear amount. However, A is a predetermined constant, t is a torque, and ΔR is a rotation increment.

  The target value correction amount calculation unit 32 corrects the target amount of the electronic control unit 11A of the charging unit 11 based on the estimated value of the accumulated wear amount of the photoconductor 10. The correction method depends on the structure, material, and the like of the photoconductor 10. For example, a predetermined function with the wear amount as a parameter can be determined and used based on an experimental value, but is not limited thereto. Usually, it is considered that the potential attenuation is increased due to wear, and therefore it is expected that the target potential is increased. However, the present invention is not limited to this. Instead of adjusting the target value, the control factor of the transfer function of the control system, for example, the integral element, the differential element, and the proportional element may be adjusted, or the transfer function itself may be changed.

  The error detection unit 33 determines whether the torque measurement value exceeds a predetermined upper limit (maximum value) and a lower limit (minimum value), or the number of times that the torque measurement value exceeds a predetermined upper limit (maximum value) and a lower limit (minimum value). Monitors whether the number of times exceeds the set number of times and detects an error. For example, when the measured torque value falls below the lower limit, or when the number of times the measured torque value falls below the lower limit becomes equal to or greater than the set number, it is expected that the cleaned toner is on the surface of the photoreceptor 10. Based on this, a cleaning error can be notified. Further, when the torque measurement value exceeds the upper limit, or when the number of times the torque measurement value exceeds the upper limit exceeds the set number, it is expected that the load on the blade of the cleaning unit 15 is too large, and the cleaning unit 15 Can be notified of problems.

  In such a configuration, the drive torque measuring unit 17 that measures the drive torque is arranged between the photoconductor 10 and the photoconductor rotation drive unit 20 that drives the photoconductor 10, and the photoconductor 10 is arranged at certain time intervals. Measure the drive torque. The measured driving torque waveform is as shown in FIG. 4. The setting of the cleaning blade, the type of toner to be used, the type in which the charging unit is in contact with the photoconductor 10 or the non-contact type, the photoconductor 10 to the paper When the toner is directly transferred to the sheet, the type of the sheet and the contact state between the sheet and the photoconductor 10, and when the toner is transferred to the sheet via the intermediate transfer medium, the contact state between the intermediate transfer medium and the photoconductor 10, etc. It depends on. Therefore, a part of the driving torque waveform to be used is determined in advance according to the set conditions (maximum value, average value, minimum value, etc.), and the load acting on the photoconductor 10 is calculated. From the calculated load and the rotation speed increment of the photoconductor 10 at the measurement interval, the amount of photoconductor wear at the measurement interval is calculated. The film thickness of the photosensitive member is calculated from the calculated cumulative amount of wear, and the charging condition is corrected based on the calculated film thickness. In addition to or separately from the charging conditions, the exposure conditions or the development conditions may be modified.

  When the drive torque waveform deviates from the preset range, it is determined that an operation failure has occurred and an error is displayed.

  According to this embodiment, the wear amount of the photoconductor 10 can be estimated by accurately grasping the load of the photoconductor 10 caused by various contact members, and an appropriate image forming control system can be estimated based on this. You can make adjustments.

  In addition, this invention is not limited to the above-mentioned Example, A various change is possible in the range which does not deviate from the meaning. For example, although the charging potential control system is corrected in the above-described example, the control system (laser output control unit 12A) such as the laser output of the exposure unit may be corrected as indicated by a broken line in FIG. It is good or both may be adjusted. Further, the selection unit 35 may be configured to select what is to be selected as the representative value of the torque measurement value.

It is a figure which shows the structure of the Example of this invention as a whole. It is a figure explaining the example of a principal part structure of the above-mentioned Example. It is a figure explaining the relationship between the cycle number of the photoconductor of the said Example, and the abrasion loss of a photoconductor. It is a figure explaining the example of the measured value of the torque of the above-mentioned Example. It is a figure explaining the modification of the above-mentioned Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photoconductor 11 Charging unit 11A Potential control part 12 Exposure unit 13 Development unit 14 Transfer unit 15 Cleaning unit 16 Paper conveyance mechanism 17 Driving torque measurement part 18 Wear amount estimation part 20 Photoconductor rotation drive part 30 Signal processing part 31 Wear amount calculation Unit 32 target value correction amount calculation unit 33 error detection unit 34 photoconductor rotation amount measurement unit 35 selection unit 100 image forming apparatus

Claims (10)

In an image forming apparatus that charges, exposes, develops, and transfers in association with the photosensitive member while rotating the photosensitive member to form an image.
Torque measuring means for measuring the driving torque of the photosensitive member;
A rotation amount measuring means for measuring the rotation amount of the photoreceptor;
Wear amount estimating means for estimating the wear amount of the photoconductor based on the measured value of the torque measuring means and the measured value of the rotation amount measuring means;
An image forming apparatus comprising: a control system correcting unit that corrects an image forming control system based on the estimated wear amount.   The image forming apparatus according to claim 1, wherein the control system correction unit corrects a target value of the charging potential.   The image forming apparatus according to claim 1, wherein the control system correction unit corrects a target value of output power of the laser output for exposure.   The image forming apparatus according to claim 1, further comprising an error detection unit that detects an error when a measured value of the torque measurement unit exceeds at least one of a set maximum value and a set minimum value.   The error detection means for detecting an error when the frequency at which the measured value of the torque measurement means exceeds at least one limit of the set maximum value and the set minimum value exceeds the set number of times. An image forming apparatus according to claim 1.   The wear amount estimating means calculates A × ΔR × t (A is a constant) from the rotation increment ΔR of the photosensitive member and the corresponding measured value t of driving torque for each measurement period, and accumulates the calculated values. The image forming apparatus according to claim 1, wherein the wear amount is determined.   The image forming apparatus according to claim 6, wherein the measurement value of the driving torque uses one of a maximum value, a minimum value, and an average value of a measurement section.   8. The image forming apparatus according to claim 7, further comprising means for setting which of a maximum value, a minimum value, and an average value of the measurement section is adopted as the measurement value of the driving torque.   3. The image forming apparatus according to claim 2, wherein a notification is made that there is a possibility that a cleaning failure has occurred based on the error detection of the error detection means. In an image forming method for forming an image by charging, exposing, developing and transferring in association with the photoconductor while rotating the photoconductor,
A step of measuring a driving torque of the photosensitive member by a torque measuring means;
A rotation amount measuring means for measuring the rotation amount of the photosensitive member;
A wear amount estimating means for determining a wear amount of the photoreceptor based on a measured value of the torque measuring means and a measured value of the rotation amount measuring means;
And a control system correction unit that controls a control amount of image formation based on the determined wear amount.

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