JP2013222149A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for averaging wear of photoreceptors included in process units while preventing the process units from being simultaneously supplied with start-up current, and for averaging the periods left till the end of the service life of the process units.SOLUTION: An image forming device 100 predicts, for each of photoreceptors 13Y, M, C, K, residual available time (residual service life), and decides the order of starting the photoreceptors 13Y, M, C, K not in operation, according to a result of prediction. The image forming device 100 is configured to adaptively control the start-up order according to the residual service life, without fixing the start-up order of the photoreceptors 13Y, M, C, K at all times.

Description

  The present invention relates to an electrophotographic image forming apparatus for forming a multicolor image, such as a laser printer or a copying machine.

  2. Description of the Related Art In recent years, image forming apparatuses that support multi-color (multi-color) are widely used in so-called in-line image forming, in which each color toner image is formed on each surface of a plurality of photoconductors as the image forming speed increases. Has been done. An in-line image forming apparatus develops a plurality of electrostatic latent images formed by independently scanning the surfaces of a plurality of photoconductors with light beams from a plurality of optical devices, using a plurality of color toners. Color toner images are formed on a plurality of photoconductors. Further, a multi-color image is formed on the intermediate transfer belt by transferring a plurality of color toner images on the intermediate transfer belt, and finally transferred onto a recording material (paper). Alternatively, a multi-color image is formed on the recording material by transferring a plurality of color toner images on the recording material on the transfer belt. In such an in-line image formation, since a plurality of color toner images can be formed simultaneously, the final image is formed in comparison with a four-pass image formation in which a plurality of color toner images are sequentially formed on a single photoconductor. The time required to form a typical multicolor image can be greatly reduced.

  However, since the in-line method uses a plurality of photoconductors and a plurality of optical devices, there is a problem that color misregistration is likely to occur in the formed multi-color image compared to the 4-pass method. The color misregistration occurs due to variations in mounting positions of the photosensitive member and the optical device, dimensional tolerances, and the like. Such color misregistration includes DC component color misregistration that occurs at a constant magnitude and AC component color misregistration whose magnitude varies periodically. The color shift of the AC component is caused by the eccentricity of the gear driving each photoconductor and the uneven rotation of the motor. In particular, low-frequency color shifts of components corresponding to the rotation period of the photoconductor due to the eccentricity of the gear driving the photoconductor are relatively easy to occur and are very noticeable visually.

  Among such color shifts, the DC component color shift can be reduced by correcting the timing of image formation. As for the color shift of the AC component, it has been studied to reduce the color shift by making the relationship between the rotational phases of a plurality of photoconductors a desired relationship. For example, in Patent Document 1, a phase detection sensor for detecting the rotational phase of a plurality of photoconductors is provided, and the operation at the time of starting the photoconductor is controlled based on the detection result of the sensor when the rotation of the photoconductor is stopped. Has been proposed. Specifically, at the time of starting the plurality of photoconductors, by starting the drive motors of the plurality of photoconductors while shifting the time so that the rotational phase relationship between the plurality of photoconductors becomes a desired relationship, The color shift of the AC component is reduced. Furthermore, even when a plurality of photoconductors are stopped at the same phase and a plurality of motors need only be started at the same time in order to match the rotational phase, a large current can be obtained by simultaneously flowing a starter current to the plurality of motors. To prevent them from flowing, start their motors at different times.

JP 2010-2754 A

  However, the above-described technique has the following problems. In an in-line image forming apparatus, the design life of an integrated cartridge composed of a plurality of parts (photosensitive member, developing device, toner container, etc.) is the shortest of the design life of each of the plurality of parts. Is equal to For example, among the parts of an integrated cartridge, the total drive time of the photoconductor becomes longer, and when the photoconductor reaches the design life most quickly, other parts (developer, toner container, etc.) reach the life. Even if it is not, the lifetime of the whole integrated cartridge has been reached. In that case, even if the developing device has not reached the end of its life or the toner remains in the toner container, the integrated cartridge cannot be used continuously.

  Also, the parts that cause the integral cartridge to reach the end of its life change depending on how the user uses it. For example, when a large number of jobs are executed in which the ratio (printing rate) of the area occupied by the formed toner image with respect to the surface area of the recording material is relatively large, the toner container consumes less toner than the toner container. However, the photoconductor can reach the end of its life earlier. Further, even when a large number of jobs with a small number of printed sheets are executed, the ratio of the driving time for the preliminary rotation to the driving time during printing increases in the photosensitive member, and the driving time of the photosensitive member becomes longer. The photoconductor can reach the end of its life earlier than the toner container.

  As described above, when a specific part of the plurality of parts provided in the integrated cartridge reaches the end of its life, it is necessary to replace the entire integrated cartridge even if other parts can be used sufficiently. Such a situation is undesirable from the viewpoint of effective use of resources. For this reason, it would be desirable to be able to use a plurality of parts in a well-balanced manner without reaching only a specific part at an early stage.

  Further, in the start timing control of a plurality of motors as described above at the time of starting the photoconductor, the photoconductor driven by the motor started first has a longer driving time than the photoconductor driven by the motor started after that. Becomes longer. For this reason, the life of the cartridge including the photoconductor that starts driving first can be shorter than the life of the cartridge including the photoconductor that starts driving later. In particular, when the activation order of a plurality of photoconductors is fixed, the time difference until the end of the life becomes large between the photoconductor activated first and the photoconductor activated last.

  As described above, in order to prevent the start timings of the starter currents from overlapping each motor, when performing control to shift the start timings of a plurality of photoconductors, if the start order is fixed, a specific cartridge is more than the other cartridges. Life can be reached early. That is, in the plurality of cartridges, the variation in the period until the end of the life becomes large, and the specific cartridge needs to be replaced particularly frequently because the specific cartridge reaches the end of its life early.

  The present invention has been made in view of the above problems. The present invention averages the degree of wear of the photosensitive members included in each cartridge while preventing the energization timings of the starting currents for a plurality of cartridges (process units) from overlapping, and determines the period until each cartridge reaches the end of its life. The purpose is to provide an averaging technique.

  The present invention can be realized as an image forming apparatus, for example. The image forming apparatus is attachable to and detachable from the main body of the image forming apparatus, and includes at least a plurality of process units having a photoconductor, and a photoconductor before the process unit reaches the end of its life. Prediction means for predicting the remaining time that can be driven from the information indicating the usage status of the process unit, and prediction order for predicting the starting order when starting the stopped photosensitive members included in the plurality of process units And determining means for determining according to the remaining time.

  According to the present invention, it is possible to average the time until each cartridge reaches the end of its life by averaging the degree of wear of the photoconductor included in each cartridge while preventing the start-up current application timings for a plurality of cartridges from overlapping. it can.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus 100 according to a first embodiment. FIG. 2 is a diagram illustrating a configuration of a drive system of a photoreceptor 13 according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of a photoconductor gear 31 according to the first embodiment. It is a figure shown about an example of the phase detection method of the photoreceptor 13 which concerns on 1st Embodiment. 2 is a block diagram of a control configuration of the image forming apparatus 100 according to the first embodiment. FIG. It is a figure which shows the several stop position of the photoreceptor 13 based on 1st Embodiment. 6 is a timing chart when stopping the photoreceptor 13 according to the first embodiment. It is a table used for control of the drive motor 32 for stopping the photoreceptor 13 at each stop position according to the first embodiment. 6 is a table showing the activation waiting time corresponding to the phase difference of the photoreceptor 13 according to the first embodiment. 6 is a timing chart showing the timing of the operation of the drive motor 32 when the photosensitive member 13 is activated according to the first embodiment. It is a figure which shows a part of data stored in RAM44 based on 1st Embodiment. 6 is a flowchart illustrating a stop control procedure for selecting a stop position of the photoconductor 13 and stopping the rotation of the photoconductor 13 according to the first embodiment. 6 is a flowchart illustrating a determination control procedure for determining the activation order of the photoreceptors according to the first embodiment. 6 is a block diagram of a control configuration of an image forming apparatus 100 according to a second embodiment. FIG. It is a figure which shows a part of data stored in RAM44 based on 2nd Embodiment. 10 is a flowchart illustrating a determination control procedure for determining the activation order of the photosensitive members 13 according to the second embodiment. 10 is a flowchart illustrating a procedure of a process for measuring the total drive time of the photosensitive member 13 according to the second embodiment. 10 is a flowchart illustrating a procedure of toner consumption measurement processing according to the second embodiment. It is a figure which shows a part of data stored in RAM44 based on 3rd Embodiment. 10 is a flowchart illustrating a determination control procedure for determining the activation order of the photosensitive members 13 according to the third embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention.

[First Embodiment]
First, as a first embodiment of an image forming apparatus according to the present invention, a case where the present invention is applied to an inline multicolor image forming apparatus will be described. In the first embodiment, the activation sequence when starting a plurality of photoconductors from a stopped state is determined according to the prediction result of the remaining time that each photoconductor can be driven before each cartridge (process unit) reaches the end of its life. It is characterized by deciding. In particular, the remaining time during which each photoconductor can be driven is determined based on the total drive time of each photoconductor after each cartridge is mounted on the main body of the image forming apparatus.

<Configuration of Image Forming Apparatus 100>
First, the configuration of an inline image forming apparatus 100 according to the first embodiment will be described with reference to FIG. The image forming apparatus 100 superimposes toner images of a plurality of colors formed using four toners of yellow (Y), magenta (M), cyan (C), and black (K). A multi-color (full-color) image is formed on the recording material (paper 21).

  The image forming apparatus 100 includes laser scanners 11Y, 11M, 11C, and 11K and cartridges 12Y, 12M, 12C, and 12K for forming four-color images. Cartridges 12Y, 12M, 12C, and 12K include toner containers 10Y, 10M, 10C, and 10K, photoreceptors 13Y, 13M, 13C, and 13K, photoreceptor cleaners 14Y, 14M, 14C, and 14K, and charging rollers 15Y, 15M, and 14K. This is a so-called integrated cartridge that includes 15C and 15K and developing rollers 16Y, 16M, 16C, and 16K, respectively.

  In the toner containers 10Y, 10M, 10C, and 10K, Y, M, C, and B toners are stored as toners for image formation of the respective colors. The photoreceptors 13Y, 13M, 13C, and 13K rotate in the directions of arrows in FIG. The photoreceptor cleaners 14Y, 14M, 14C, and 14K are disposed at positions that contact the photoreceptors 13Y, 13M, 13C, and 13K, respectively.

  The cartridges 12Y, 12M, 12C, and 12K are detachable from the main body of the image forming apparatus 100. When any device (part) included in the cartridges 12Y, 12M, 12C, and 12K reaches the end of its life, the cartridge itself that includes the device has reached the end of its life. In this case, the cartridge needs to be replaced with a new cartridge. In the present embodiment, the cartridges 12Y, 12M, 12C, and 12K are detachable from the main body of the image forming apparatus 100, and each include the photosensitive members 13Y, 13M, 13C, and 13K. Functions as multiple process units.

  The image forming apparatus 100 further transfers the intermediate transfer belt 17 at a position in contact with the photoreceptors 13Y, 13M, 13C, and 13K, and performs primary transfer at a position facing the photoreceptors 13Y, 13M, 13C, and 13K with the intermediate transfer belt 17 in between. Rollers 18Y, 18M, 18C, and 18K are provided. In the image forming apparatus 100, corresponding to the intermediate transfer belt 17, a belt cleaner 19 that collects (scraps) toner remaining on the surface of the intermediate transfer belt 17, and the collected toner is stored as waste toner. A waste toner container 20 is also disposed.

  In the cassette 22 that stores the paper 21, a size guide 23 that regulates the position of the paper 21 in the cassette 22 and a paper presence sensor 24 that detects the presence or absence of the paper 21 in the cassette 22 are disposed. A feeding roller 25, separation rollers 26 a and 26 b, and a registration roller 27 are arranged as rollers for transporting the paper 21 along the transport path of the paper 21. A registration sensor 28 is disposed in the vicinity of the downstream side of the registration roller 27 in the conveyance direction of the paper 21. Further, a secondary transfer roller 29 is disposed at a position in contact with the intermediate transfer belt 17, and a fixing device 30 is disposed downstream of the secondary transfer roller 29 in the conveyance direction of the paper 21.

<Electrophotographic process of image forming apparatus 100>
The image forming apparatus 100 uniformly charges the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K with the charging rollers 15Y, 15M, 15C, and 15K in the dark place in the cartridges 12Y, 12M, 12C, and 12K. Next, when the laser scanners 11Y, 11M, 11C, and 11K irradiate the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K with laser light modulated according to image data, the charged charges in the portions irradiated with the laser light are generated. Removed. As a result, electrostatic latent images are formed on the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K. The developing rollers 16Y, 16M, 16C, and 16K adhere the charged toner from the toner containers 10Y, 10M, 10C, and 10K to the electrostatic latent images on the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K. As a result, the developing rollers 16Y, 16M, 16C, and 16K form toner images of the respective colors on the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K. Thereafter, the primary transfer rollers 18Y, 18M, 18C, and 18K sequentially transfer the toner images of the respective colors on the surfaces of the photoreceptors 13Y, 13M, 13C, and 13K to the surface of the intermediate transfer belt 17 in a superimposed manner. As a result, a multicolor image composed of four color toner images is formed on the surface of the intermediate transfer belt 17.

  On the other hand, the paper 21 in the cassette 22 is fed and conveyed in accordance with the toner image formation timing described above. The paper 21 is fed from the cassette 22 onto the conveyance path by the paper feed roller 25. When a plurality of sheets 21 are set in the cassette 22, the separation rollers 26 a and 26 b convey the sheets 21 one by one toward the registration roller 27. At the nip portion between the intermediate transfer belt 17 and the secondary transfer roller 29, the secondary transfer roller 29 transfers the toner image on the intermediate transfer belt 17 onto the paper 21 conveyed by the registration roller 27. Thereafter, the fixing device 30 applies heat and pressure to the toner image on the paper 21 to fix the toner image on the paper 21. Finally, the sheet 21 is discharged outside the image forming apparatus 100.

  Hereinafter, the subscripts Y, M, C, and K attached to the above-described elements may be omitted for simplification of description. For example, in the case where the photoconductor 13 is simply described, this represents the photoconductors 13Y, 13M, 13C, and 13K. For the suffixes Y, M, C, and K, for example, the photoconductors 13Y, 13M, 13C, and 13K are simply expressed as photoconductors 13Y, M, C, and K.

<Configuration of Photoreceptor 13>
Next, with reference to FIG. 2 and FIG. 3, a driving configuration of the photoconductor 13 according to the first embodiment will be described. In FIG. 2, the photoconductors 13Y, 13M, 13C, and 13K and the photoconductor gears 31Y, 31M, 31C, and 31K are connected so as to always operate at the same phase by coupling (not shown). . Drive motors 32Y, M, C, and K are connected to the photoconductor gears 31Y, M, C, and K, respectively. The drive motors 32Y, 32M, 32C, and 32K drive the photoconductor gears 31Y, 31M, 31C, and 31K, respectively, thereby driving the photoconductors 13Y, 13M, 13C, and 13K.

  FIG. 3 shows the respective configurations of the photoconductor gear 31. (a), (b), and (c) show the photoconductor gear 31 in three directions: a side direction, an oblique direction, and a front direction, respectively. It shows the case observed from. The photoreceptor gear 31 is provided with a slit plate 34. The slit plate 34 is provided with slits 35 (35a and 35b). The phase detection sensor 36 including a light emitting unit and a light receiving unit can detect the rotational phase of the photosensitive member 13 by detecting these slits 35 (35a and 35b). The slits 35a and 35b have different lengths, and the slit 35a is shorter than the slit 35b. For this reason, the phase detection sensor 36 can detect and detect the slits 35a and 35b.

  When the photoconductor gears 31Y, 31M, 31C, and 31K are manufactured in the same mold, the direction of the eccentricity of the photoconductor gears 31Y, 31M, 31C, and 31K and the positional relationship between the slits 35Y, 35M, 35C, and 35K The same applies to the photoconductor gears 31Y, M, C, and K. For this reason, the relationship between the phase detected by the slits 35Y, 35M, 31C, 35K and the phase of the photoconductor gears 31Y, 31M, 31C, 31K is the same for all the photoconductor gears 31Y, 31M, 31C, 31K. . In other words, the relationship between the phases detected by the slits 35Y, 35M, 35C, and 35K and the phases of the photoreceptors 13Y, 13M, 13C, and 13K is the same for all the photoreceptors 13Y, 13M, 13C, and 13K.

  On the other hand, when the photoconductor gears 31Y, 31M, 31C, and 31K are manufactured in a plurality of different types, for example, the phases of the slits Y, M, C, and K and the photoconductors 13Y, 13M, 13C, and 13K are as follows. It is possible to specify the relationship. In this case, the toner pattern formed at equal time intervals on the photosensitive member 13 is transferred onto the intermediate transfer belt 17 as shown in FIG. 4 and the pattern detection sensor 37 reads the toner pattern, thereby accumulating the pattern intervals. Find the fluctuation component. From the obtained cumulative fluctuation component, the relationship between the slits 35Y, 35M, 35C, and the phase of the photoreceptors 13Y, 13M, 13C, and 13K can be specified. In addition, about the specific identification method of the said relationship, since the relevance is low with description of this invention, description is abbreviate | omitted. In the following, it is assumed that the relationship between the slits 35Y, M, C, K and the phases of the photoconductors 13Y, M, C, K is the same for all the photoconductors 13Y, M, C, K. explain.

<Control Configuration of Image Forming Apparatus 100>
A control configuration of the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. The CPU 42 is connected to the ROM 43, the RAM 44, the nonvolatile memory 45, the motor driving unit 50, and the phase detection sensors 36Y, M, C, and K. The CPU 42 uses the RAM 44 as a work area, reads out the control program and various tables stored in the ROM 43 to the RAM 44, and controls the operation of the image forming apparatus 100 based on them. The motor drive unit 50 is connected to the drive motors 32Y, 32M, 32C, 32K, and outputs drive control signals for starting, stopping, and controlling the rotation speed of the drive motors 32Y, 32M, 32C, 32K. , M, C, and K to control their drive. The drive motors 32Y, 32M, 32C, 32K transmit an FG pulse signal indicating the rotational speed of the drive motors 32Y, 32M, 32C, 32K to the motor drive unit 50. The motor drive unit 50 controls the drive of the drive motors 32Y, 32M, 32C, and 32K based on the transmitted FG pulse signal.

  The CPU 42 starts or stops the drive motors 32Y, 32M, 32C, and 32K using the motor drive unit 50. In the present embodiment, the target rotational speeds when the drive motors 32Y, 32M, 32C, 32K are rotated are the photoreceptors 13Y, M, C, K, the photoreceptor gears 31Y, M, C, K, and the slits 35Y, M. , C, and K are set to rotate at a speed of 1200 ms. The drive motors 32Y, M, C, and K are each 1500 ms from the stop state until reaching a state where the drive motor 32Y is rotating at the target rotation speed and from the state where the drive motor 32Y is rotating at the target rotation speed until reaching the stop state. It takes time. Meanwhile, the CPU 42 causes the motor driving unit 50 to slow up and slow down the rotation of the photoreceptors 13Y, 13M, 13C, and 13K at a constant acceleration.

<Stopping position of photoconductor 13>
When stopping the operation (rotation) of the photoconductor 13Y, the CPU 42 calculates the time from the reference timing to the timing of stopping the drive motor 32Y with reference to the timing at which the pulse signal is output from the phase detection sensor 36Y. To do. Further, after the calculated time has elapsed from the reference timing, the CPU 42 starts decelerating the drive motor 32Y and finally stops it. Thereby, the CPU 42 stops the photosensitive member 13Y at a predetermined rotational phase. Note that the CPU 42 performs the same control as the photoconductor 13Y when stopping the photoconductors 13M, 13C, and 13K.

  In the present embodiment, when the rotating photoconductors 13Y, 13M, 13C, and 13K are stopped, they are stopped at any one of the first to fourth stop positions shown in FIG. The stop positions of the photoreceptors 13Y, 13M, 13C, and 13K can always be the same stop position for all the photoreceptors 13Y, 13M, 13C, and 13K. However, by providing a plurality of different stop positions, it is possible to prevent local wear of the gear and the drum when the photosensitive member 13 is started and stopped. Therefore, in the present embodiment, four stop positions (first to fourth stop positions) in which the rotation phase of the photoconductor 13 is shifted by 90 degrees are used.

  FIGS. 7A to 7D show timing charts when the photosensitive member 13 is stopped at the first to fourth stop positions shown in FIGS. 6A to 6D, respectively.

(1) When stopping the photoreceptor 13 at the first stop position When the slit 35a is detected first by the phase detection sensor 36, the CPU 42 starts decelerating the drive motor 32 after the time Ta1 has elapsed from the detection timing. Then stop. On the other hand, when the slit 35b is detected first, the CPU 42 starts decelerating the drive motor 32 and stops after the elapse of time Tb1 from the detection timing.

(2) When the photosensitive member 13 is stopped at the second stop position When the slit 35a is detected first, the CPU 42 starts to decelerate and stop the drive motor 32 after the time Ta2 has elapsed from the detection timing. On the other hand, when the slit 35b is detected first, the CPU 42 starts decelerating the drive motor 32 and stops after the elapse of time Tb2 from the detection timing.

(3) When the photosensitive member 13 is stopped at the third stop position When the slit 35a is detected first, the CPU 42 starts to decelerate and stop the drive motor 32 after the time Ta3 has elapsed from the detection timing. On the other hand, when the slit 35b is detected first, the CPU 42 starts decelerating the drive motor 32 and stops after the elapse of time Tb3 from the detection timing.

(4) When the photosensitive member 13 is stopped at the fourth stop position When the slit 35a is detected first, the CPU 42 starts decelerating the drive motor 32 and stops after the passage of time Ta4 from the detection timing. On the other hand, when the slit 35b is detected first, the CPU 42 starts decelerating the drive motor 32 and stops after the elapse of time Tb4 from the detection timing.

  In the present embodiment, the CPU 42 uses the table 800 shown in FIG. 8 in order to stop the photosensitive member 13 at any one of the first to fourth stop positions described above. Data corresponding to the table 800 may be stored in the ROM 43 in advance. The table 800 includes the time from when any of the slits (slit 35a or slit 35b) is detected by the phase detection sensor 36 until the deceleration of the drive motor 32 is started. The CPU 42 may perform the above-described control according to the table 800. In the table 800, the phase (angle) corresponding to each stop position of the photosensitive member 13 is based on the case where the slit 35b is at the position of the phase detection sensor 36 (corresponding to FIG. 6A) as a reference (0 degree). Yes.

<Stop Control of Photoreceptor 13>
Next, referring to FIG. 11 and FIG. 12, in order to stop the rotation of the photoconductor 13 by selecting the stop position when the photoconductor 13 is stopped from any of the first to fourth stop positions described above. The stop control will be described.

  FIG. 11 shows a part of data stored in the RAM 44 and used when the CPU 42 controls the driving of the photosensitive member 13. The CPU 42 stores data indicating the stop positions of the photoconductors 13Y, 13M, 13C, 13K, the total drive time of the photoconductors 13Y, 13M, 13K, and the photoconductor 13 to be activated first to fourth in the RAM 44. Store. Further, the CPU 42 copies these data stored in the RAM 44 to the nonvolatile memory 45 so that the data can be held even when the power of the image forming apparatus 100 is turned off. When the power of the image forming apparatus 100 is changed from the OFF state to the ON state, the CPU 42 copies the data stored in the nonvolatile memory 45 to the RAM 44 and uses it.

  FIG. 12 is a flowchart showing a stop control procedure for selecting the stop position of the photoreceptor 13 and stopping the rotation of the photoreceptor 13. The processing of each step shown in FIG. 12 is realized on the image forming apparatus 100 by the CPU 42 reading the control program stored in the ROM 43 into the RAM 44 and executing it. The CPU 42 performs the same processing for each of the photoreceptors 13Y, 13M, 13C, and 13K (drive motors 32Y, 32M, 32C, 32K).

  For example, the CPU 42 starts stop control for stopping the photosensitive member 13 that is rotationally driven in accordance with the end of image formation in the image forming apparatus 100. First, in S101, the CPU 42 starts detecting the slit 35a or 35b by the phase detection sensor 36. If the CPU 42 determines that any one of the slits 35 (slit 35a or 35b) has been detected (Yes in S101), the process proceeds to S102.

  In S102, the CPU 42 rotates the photoconductor 13 in the shortest time after starting to decelerate the rotation speed of the photoconductor 13 after any one of the first to fourth stop positions is detected. Select a stop position that can be stopped. Specifically, the CPU 42 refers to the table 800, and among the first to fourth stop positions, the time until the rotation speed of the photoconductor 13 starts to be reduced in order to stop the rotation of the photoconductor 13. The stop position with the shortest is selected. According to the table 800, when the slit 35a is detected in S101, the CPU 42 selects the first stop position corresponding to Ta1 (= 0). Further, when the slit 35b is detected in S101, the CPU 42 selects the third stop position corresponding to Tb3 (= 0).

  Next, in S103, the CPU 42 waits for a predetermined time (Ta1 or Tb3) until the rotation speed is decelerated to stop the photosensitive member 13 at the stop position selected in S102. When the predetermined time has elapsed, the CPU 42 starts decelerating the rotational speed of the drive motor 32 in S104. When the drive motor 32 stops and the photosensitive member 13 stops at the selected stop position, the CPU 42 stores the selected stop position in the RAM 44 in S105 and also stores it in the nonvolatile memory 45 in S106. As described above, the CPU 42 ends the stop control of the photosensitive member 13.

<Decision Control for Starting Order of Photoconductor 13>
Next, with reference to FIG. 13, the determination control for determining the activation order when activating the plurality of photoconductors 13Y, 13M, 13C, 13K being stopped will be described. For each of the cartridges 12Y, 12M, 12C, and 12K (the cartridge 12), the CPU 42 according to the remaining time during which the photosensitive member 13 included in the cartridge 12 can be driven before the cartridge 12 reaches the end of its life. The starting order of the photosensitive member 13 is determined. Further, the CPU 42 predicts the remaining time during which the photosensitive member 13 can be driven from information indicating the usage status of the cartridges 12Y, 12M, 12C, and 12K. That is, in the present embodiment, the starting order when starting the stopped photoreceptors 13Y, 13M, 13C, and 13K is not always fixed, but the prediction is based on the usage status of the cartridges 12Y, 12M, 12C, and 12K. Then, it is determined adaptively according to the remaining time during which each photoconductor can be driven.

  As a result, it is possible to prevent the specific cartridge 12 from always reaching the end of its life due to the specific photoconductor 13 reaching its end of life at an early stage as in the case where the starting order of the photoconductors 13 is fixed. be able to. Further, it is possible to average the life bias of the photoconductor 13 and the life bias of the cartridge 12.

  The prediction of the remaining time during which the photoconductor 13 can be driven and the determination of the activation order of the photoconductor 13 can be executed at an arbitrary timing. Hereinafter, as an example, a case where the remaining time is predicted and the activation order of the photosensitive member 13 is determined when the driving of the photosensitive member 13 included in the cartridge 12 is stopped according to the end of image formation will be described. By predicting the remaining time at such timing, the latest usage status of the cartridge 12 until the timing at which the photosensitive member 13 stops is used to determine the remaining time prediction result and to determine the activation order of the photosensitive member 13. It can be reflected. As a result, the life bias of the photosensitive member 13 can be more effectively averaged, and the life bias of the cartridge 12 can be more effectively averaged.

  In the following, as an example, the CPU 42 will be described with respect to a case where the startup sequence when starting the stopped photoconductors 13Y, 13M, 13C, and 13K is determined as the longest predicted remaining time. As a result, when the photoconductor 13 is activated, the cartridge 12 having a long remaining time until the photoconductor 13 reaches the end of its life is preferentially activated first. As a result, it is possible to prevent the specific cartridge 12 from always reaching the end of its life due to the specific photoconductor 13 reaching its end of life at an early stage as in the case where the starting order of the photoconductors 13 is fixed. be able to. Further, it is possible to more effectively average the life bias of the photoconductor 13 and more effectively average the life bias of the cartridge 12.

  In the following description, the CPU 42 predicts the remaining time during which the photosensitive member 13 included in the cartridge 12 can be driven before the cartridge 12 reaches the end of its life, after the photosensitive member 13 is mounted on the main body of the image forming apparatus 100. The case where it carries out based on the measurement result of this total drive time is demonstrated. In other words, as information indicating the usage status of the cartridges 12Y, 12M, 12C, and 12K, the total driving time after the photoconductor 13 is mounted on the main body of the image forming apparatus 100 is used as an example, and the photoconductor 13 is displayed. Predict the remaining drive time.

  FIG. 13 is a flowchart illustrating a determination control procedure for determining the activation order of the photoreceptors 13 according to the present embodiment. The processing of each step shown in FIG. 13 is realized on the image forming apparatus 100 by the CPU 42 reading out the control program stored in the ROM 43 to the RAM 44 and executing it. Note that the CPU 42 stores the measurement result of the total driving time of the photosensitive member 13 after the cartridge 12 is mounted on the main body of the image forming apparatus 100 in the RAM 44 as shown in FIG.

  In S201 to S203, the CPU 42 determines whether or not each of the drive motors 32Y, 32M, 32C, 32K (drive motor 32) has stopped, and each of the photoreceptors 13Y, 13M, 13C, and 13K (photoreceptor 13). The total drive time is measured every second. After waiting for 1 second to elapse while the drive motor 32 is activated (rotated) in S201, 1 second is added to the total drive time of the photoconductor 13 in the RAM 44 in S202. Further, in S203, the CPU 42 determines whether or not the drive motor 32 is stopped. If not, the CPU 42 returns the process to S201 and waits for one second to elapse. On the other hand, if the drive motor 32 is stopped, the process proceeds to S204. Here, the drive time measurement is described as one second as an example here, but the present invention is not limited to this, and can be set as appropriate according to the accuracy with which the drive time is desired to be measured.

  In S204 to S207, the CPU 42 determines and determines the starting order when starting the stopped photosensitive members 13Y, 13M, 13C, and 13K based on the total driving time of the photosensitive members 13Y, 13M, 13C, and 13K. Data indicating the activation order is stored in the RAM 44. As shown in FIG. 11, the RAM 44 stores data indicating the first to fourth activated photoconductors 13. Specifically, the CPU 42 selects the photoconductors 13Y, 13M, 13C, and 13K. Then, it is determined that the measured total drive time (stored in the RAM 44) should be started in ascending order.

  In the processing of S204 to S207, the difference between the predetermined total driving time corresponding to the design life of the photoconductor 13 and the measured total driving time is predicted as the remaining time during which the photoconductor 13 can be driven, and the above-described processing is performed. This corresponds to the order in which the remaining times are longest.

  Finally, in S <b> 208, the CPU 42 also stores (updates) the total driving time of each photoconductor 13 stored in the RAM 44 in the nonvolatile memory 45. As described above, the CPU 42 ends the control for determining the activation order of the photosensitive members 13. As described above, when the image forming apparatus 100 is powered on, the data stored in the nonvolatile memory 45 is copied to the RAM 44. When any one of the photoconductors 13 is replaced, the value of the total drive time in the RAM 44 and the nonvolatile memory 45 corresponding to the replaced photoconductor 13 is cleared to zero.

  In the image forming apparatus 100, every time driving of the drive motors 32Y, 32M, 32C, and 32K is stopped in accordance with the end of image formation, etc., start-up when the stopped photoconductor 13 is started according to the procedure shown in FIG. Determine the order. Further, the data indicating the determined activation order stored in the RAM 44 and the nonvolatile memory 45 is updated with the newly determined activation order.

<Starting Control of Photoconductor 13>
Next, activation control for activating the photoreceptors 13Y, M, C, and K that are stopped will be described. When activating the photoconductors 13Y, 13M, 13C, and 13K, the photoconductors are activated in the order indicated by the information stored in the RAM 44, and each photoconductor is activated at a timing when the rotation phases thereof are the same. The activation order of the photoconductors 13Y, 13M, 13C, and 13K is stored in the RAM 44 by the above-described determination control. Here, it is assumed that data indicating the photosensitive member 13Y, the photosensitive member 13C, the photosensitive member M, and the photosensitive member K are stored in the RAM 44 as the first to fourth starting photosensitive members. That is, it is assumed that the photoconductor 13Y, the photoconductor 13C, the photoconductor M, and the photoconductor K are activated in this order.

  When the CPU 42 starts the activation control of the photoreceptors 13Y, 13M, 13C, and 13K, first, the activation of the photoreceptor 13K is started by starting the drive motor 32K. Next, the CPU 42 activates the drive motor 32C after a predetermined time has elapsed from the start of activation of the drive motor 32K in accordance with the stop position of the photoreceptor 13K and the stop position of the photoreceptor 13C. Thereafter, similarly, the drive motor 32M is activated after a predetermined time has elapsed from the start of activation of the drive motor 32C in accordance with the stop position of the photoreceptor 13C and the stop position of the photoreceptor 13M. Finally, the drive motor 32Y is activated after a predetermined time has elapsed from the start of activation of the drive motor 32M in accordance with the stop position of the photoreceptor 13M and the stop position of the photoreceptor 13Y.

  The acceleration and time from when the drive motor 32 (each photoconductor 13) is started until the rotation speed reaches the target rotation speed is constant for all the drive motors 32 (photoconductors 13). For this reason, in the present embodiment, in consideration of the phase difference between the stop position of the photosensitive member 13 that starts first and the stop position of the photosensitive member 13 that starts next, the drive corresponding to the photosensitive member 13 that starts next. The motor 32 is started. As a result, the rotational phases of the photoconductors 13Y, 13M, 13C, and 13K after the activation of all the drive motors 32Y, 32M, 32C, 32K can be made the same.

  FIG. 9 shows the phase difference between the photosensitive members 13 corresponding to the stop positions of the photosensitive member 13 that starts first and the photosensitive member 13 that starts next, and the photosensitive member that starts next from the start of starting the photosensitive member 13 that starts first. A table 900 showing the relationship with the waiting time until the start of the body 13 is described. Data corresponding to the table 900 may be stored in the ROM 43 in advance. As shown in the table 900, in the present embodiment, each of the photoreceptors 13Y, 13M, 13C, and 13K has four stop positions, so there are 16 combinations of stop positions between different photoreceptors 13. The CPU 42 refers to the table 900 stored in the ROM 43 when starting up the photoconductors 13, and uses the waiting time corresponding to the stop position of each photoconductor 13 to drive each photoconductor 13 (drive motor 32). ) Control the operation timing.

  FIG. 10 is a timing chart showing the operation timing of the drive motor 32 when the photosensitive member 13 is activated. Here, four cases (cases 1 to 4 in FIG. 9) in which the photosensitive body 13K to be driven first is in the first stop position will be described with reference to FIG. FIGS. 10A to 10D show a case where the photosensitive member 13K that starts first is in the first stop position, and the photosensitive member 13C that starts next is in the first to fourth stop positions, respectively.

(1) Photoconductor 13K: First stop position, Photoconductor 13C: First stop position As shown in FIG. 10A, the drive motor 32C is started after a lapse of time Td1 from the start of the start of the drive motor 32K. After the drive motors 32K and 32C reach the target rotational speed, the rotational phases of the photoconductors 13K and 13C are in the same state. In the table 900, since the phase difference between the photoconductors 13K and 13C is 0 degree, the activation waiting time of the drive motor 32C is set to time Td (= 1200 ms). This time Td1 corresponds to the time (= 1200 ms) required for each photoconductor 13 rotating at the target rotation speed to make one rotation (rotation of 360 degrees having the same phase as 0 degree). As described above, the time difference between the activation timings of the drive motors 32K between the photoconductors 13K and 13C is set as one turn of each photoconductor 13 in order to consume each photoconductor 13 on average. Even when the time Td1 = 0 [ms], it is possible to make the rotational phases of the photoconductors 13K and 13C the same.

(2) Photoconductor 13K: First stop position, Photoconductor 13C: Second stop position As shown in FIG. 10B, the drive motor 32C is started after a lapse of time Td2 from the start of the start of the drive motor 32K. After the drive motors 32K and 32C reach the target rotational speed, the rotational phases of the photoconductors 13K and 13C are in the same state. In the table 900, since the phase difference between the photoconductors 13K and 13C is 90 degrees, the activation waiting time of the drive motor 32C is set to time Td2 (= 300 ms). This time Td2 corresponds to the time required for the photoconductor 13 rotating at the target rotation speed to make a quarter turn (90 ° rotation).

(3) Photoconductor 13K: First stop position, Photoconductor 13C: Third stop position As shown in FIG. 10C, by starting the drive motor 32C after a lapse of time Td3 from the start of the start of the drive motor 32K. After the drive motors 32K and 32C reach the target rotational speed, the rotational phases of the photoconductors 13K and 13C are in the same state. In the table 900, since the phase difference between the photoconductors 13K and 13C is 180 degrees, the activation waiting time of the drive motor 32C is set to time Td3 (= 600 ms). This time Td2 corresponds to the time required for the photoconductor 13 rotating at the target rotation speed to make a half turn (180 ° rotation).

(4) Photoconductor 13K: First stop position, Photoconductor 13C: Fourth stop position As shown in FIG. 10 (d), by starting the drive motor 32C after a lapse of time Td4 from the start of the start of the drive motor 32K. After the drive motors 32K and 32C reach the target rotational speed, the rotational phases of the photoconductors 13K and 13C are in the same state. In the table 900, since the phase difference between the photoconductors 13K and 13C is 270 degrees, the activation waiting time of the drive motor 32C is set to time Td4 (= 900 ms). This time Td2 corresponds to the time required for the photoreceptor 13 rotating at the target rotation speed to make 3/4 rotation (rotation of 270 degrees).

  In FIG. 10, only cases 1 to 4 of the table 900 are shown. However, in cases 5 to 16 as well, in accordance with the phase difference between the photoconductors 13K and 13C, the time Td1 to Td4 from the start of activation of the drive motor 32K. The drive motor 32C may be activated after any of the passages. As a result, the rotational phases of the photoconductors 13K and 13C can be made the same. Further, FIG. 10 shows the relationship between the photoconductors 13K and 13C, but it is possible to rotate all the photoconductors with the same phase by similarly controlling the start-up between the other photoconductors.

<Effect of this embodiment>
Next, the effect of the start control according to the present embodiment will be described by comparing the case where the start order of the photoconductors 13Y, 13M, 13C, and 13K is always fixed. In this comparative example, it is assumed that the drive stop requests for the photoconductors 13Y, 13M, 13C, and 13K are made simultaneously for all the photoconductors, so that all the photoconductors stop at the same phase. However, in the comparative example, when starting the stopped photoconductors 13Y, 13M, 13C, and 13K, the start-up time of each photoconductor 13 is set to 1200 ms in order to avoid overlap of start-up currents for the photoconductors 13. (That is, the time required for each photoconductor 13 to make one rotation) is shifted and started.

In this comparative example, the photoconductor 13 that is always started first is always driven for a longer time than the photoconductor 13 that is started after that, and the wear is most severe. As a result, the photoconductor 13 that is always started first reaches the earliest of the photoconductors 13Y, 13M, 13C, and 13K. Assuming a case where a single color print is executed 1500 times using a fixed starting order of the photoreceptors 13Y, 13M, 13C, and 13K, the total drive time of each photoreceptor 13 is as follows. Become.
The total drive time of the photoconductor 13Y is 5400000 ms (= 1200 ms × 3 × 1500 times) longer than the drive time of the photoconductor 13K.
The total drive time of the photoconductor 13M is longer by 3600000 ms (= 1200 ms × 2 × 1500 times) than the drive time of the photoconductor 13K.
The total drive time of the photoconductor 13C is 1800000 ms (= 1200 ms × 1 × 1500 times) longer than the drive time of the photoconductor 13K.

As a result, when the driving time of the photoconductors 13 per color print is about 30 seconds, the degree of wear of each photoconductor 13 is as follows.
The photoconductor 13Y has a longer drive time and wear level for 180 color prints than the photoconductor 13K.
The photoconductor 13M has a longer driving time and a degree of wear for 120 color prints than the photoconductor 13K.
The photoconductor 13C has a longer driving time and wear level for 60 color prints than the photoconductor 13K.
Since the photosensitive member 13K is always activated last, the extra driving time is 0 ms.

  In contrast to the comparative example described above, in the start-up control of this embodiment, each of the start-up waiting times for phase alignment of the photoconductors 13Y, 13M, 13C, and 13K when 1500 color prints are executed, The extra driving time of the photoreceptor 13 is averaged to the driving time for 90 color prints. As a result, all the photoconductors 13Y, 13M, 13C, and 13K can be consumed uniformly.

  As described above, in this embodiment, when the photoreceptors 13Y, 13M, 13C, and 13K are stopped, the remaining driveable time (that is, the remaining lifetime) is predicted, and the stopped photoreceptors 13Y, 13Y, When M, C, and K are activated, it is determined that the remaining time should be activated in descending order. As described above, the activation order of the photosensitive members 13Y, 13M, 13C, and 13K is not always fixed, but the activation order is controlled so that the photosensitive elements 13Y, M, C, and K are activated in order from the longest remaining life.

  As a result, while the energization timing of the starting current to the drive motor 32 corresponding to each photoconductor 13 is prevented from overlapping, the degree of wear of each photoconductor 13 is averaged, and the time until each photoconductor 13 reaches the end of its life is obtained. Can be averaged. That is, it is possible to reduce variations in time until each photoconductor 13 reaches the end of its life. As a result, the period until each cartridge 12 reaches the end of its life can be averaged, and only a specific cartridge 12 can be prevented from reaching the end of its life early.

  In the present embodiment, an example of selecting a stop position that can be stopped in the shortest time after starting reduction of the rotation speed of each photoconductor when performing stop control of the photoconductor 13 has been described. However, the method for selecting the stop position of the photoconductor 13 may be any other method as long as the method can grasp the stop position of each photoconductor 13. For example, for each photoconductor 13, any one of a plurality of stop positions (for example, the above-described first to fourth stop positions) may be selected at random. In this case, it is possible to avoid local shaving and wear of each photoconductor 13.

  Further, when starting each photoconductor 13, it is not necessary to control the photoconductors 13 to rotate at the same phase as described above. For example, in order to prevent the energization timings of the activation currents for the drive motors 32 corresponding to the respective photoconductors 13 from being overlapped, the respective photoconductors 13 are sequentially activated in the activation order determined by the above-described procedure at regular time intervals. May be.

  In addition, the configurations of the image forming apparatus 100 and the photoconductor 13 described in the present embodiment, the time intervals when the photoconductors 13 are sequentially started up are merely examples, and can be appropriately set by individual image forming apparatuses. is there.

[Second Embodiment]
In the second embodiment, in the determination control of the activation order of each photoconductor 13, each photoconductor is considered in consideration of the remaining amount of toner contained in each toner container 10 in addition to the total drive time of each photoconductor 13. 13 start orders are determined. In the following description, only parts different from the first embodiment will be described for simplification of description. For example, the configuration of the image forming apparatus 100 is the same as the configuration illustrated in FIG. 1 in the first embodiment.

  As in the first embodiment, when the activation order of each photoconductor 13 is determined only by the remaining time (remaining life) until each photoconductor 13 reaches the end of its life, in the cartridge 12 with a low printing rate, the photoconductor 13 When the toner reaches the end of its life, a large amount of toner may still remain in the toner container 10.

  For example, of the two cartridges, the remaining life of the photoreceptor 13 of the cartridge A is 50% and the remaining amount of toner is 60%, the remaining life of the photoreceptor 13 of the cartridge B is 40%, and the remaining amount of toner is 30%. In some cases, the activation order of the photoreceptors 13 can be determined as follows. That is, when only the remaining life of the photoconductor 13 is compared, the photoconductor 13 of the cartridge A is controlled to start before the photoconductor 13 of the cartridge B. However, in the cartridge A, the remaining amount of toner is larger than the remaining life of the photoconductor 13, and a large amount of toner remains when the photoconductor 13 reaches the end of its life. On the other hand, in the cartridge B, the remaining amount of toner is small with respect to the remaining life of the photosensitive member 13, and there is a high possibility that the remaining amount of toner will run out earlier (the toner container 10 reaches the end of its life).

  In this way, when any part in the cartridge reaches the end of its life particularly earlier than the other parts, it cannot be said that all parts are used up in a balanced manner, and it is not desirable from the viewpoint of effective use of resources. In view of this, the present embodiment is characterized in that the activation order of each photoconductor 13 is determined in consideration of not only the remaining life of the photoconductor 13 included in each cartridge 12 but also the remaining amount of toner in the toner container 10. To do. As a result, the photoconductor 13 is consumed according to the usage status of other parts (the toner container 10 in this embodiment), and the photoconductor 13 and the toner container 10 can be used up in a balanced manner.

<Control Configuration of Image Forming Apparatus 100>
A control configuration of the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. As can be seen from FIG. 14, the difference from the first embodiment (FIG. 5) is that printing rate measurement sensors 40Y, 40M, 40C, 40K are added. The printing rate measurement sensors 40Y, 40M, 40C, and 40K are connected to the CPU 42, and transmit data indicating the printing rate measurement result to the CPU 42. The printing rate corresponds to the ratio of the area occupied by the formed toner image (that is, the toner attached to the surface of the recording material by image formation) to the area of the surface of the recording material. Each time the image formation is performed in the image forming apparatus 100, the print rate measuring sensors 40Y, 40M, 40C, 40K measure the amount of toner adhering to each recording material, calculate the print rate, and calculate the calculation result. It transmits to CPU42.

<Decision Control for Starting Order of Photoconductor 13>
Next, determination control for determining the activation order of the photoreceptors 13Y, 13M, 13C, and 13K according to the present embodiment will be described with reference to FIGS.

  FIG. 15 shows a part of data stored in the RAM 44 and used when the CPU 42 controls the driving of the photosensitive member 13. As in the first embodiment, the CPU 42 stops the photoconductors 13Y, 13M, 13C, 13K, the total driving time of the photoconductors 13Y, 13M, 13C, and 13K, and the first to fourth photoconductors. Data indicating 13 is stored in the RAM 44. In the present embodiment, the CPU 42 further includes the total toner consumption amount, the remaining toner amount, and the photoreceptors 13Y, M, C, and K for the cartridges 12Y, 12M, 12C, and 12K (toner containers 10Y, 10M, 10C, and 10K). The ratio of the K driveable time is also stored in the RAM 44.

  FIG. 16 is a flowchart showing a determination control procedure for determining the activation order of the photoreceptors 13 according to this embodiment. The processing of each step shown in FIG. 16 is realized on the image forming apparatus 100 by the CPU 42 reading out the control program stored in the ROM 43 to the RAM 44 and executing it.

  First, in S <b> 301, the CPU 42 performs a measurement process of the total driving time after the photosensitive member 13 is mounted on the main body of the image forming apparatus 100. Here, with reference to the flowchart of FIG. 17, the procedure of the process for measuring the total drive time of the photoreceptor 13 executed in S301 will be described. In S401 to S403, the CPU 42 performs the same processing as in S201 to S203 (FIG. 13) in the first embodiment, so that the total drive of each of the photoreceptors 13Y, 13M, 13C, and 13K (photoreceptor 13) is performed. Measure time. The CPU 42 stores the measurement result of the total driving time of each photoconductor 13 in the RAM 44 as shown in FIG. Further, in S <b> 404, the CPU 42 also stores (updates) the total driving time of each photosensitive member 13 stored in the RAM 44 in the nonvolatile memory 45.

  Next, in S <b> 302, the CPU 42 performs a measurement process of the total toner consumption of each cartridge 12 after the cartridge 12 is mounted on the main body of the image forming apparatus 100. Here, with reference to the flowchart of FIG. 18, the procedure of the total toner consumption measurement process of each cartridge 12 executed in S302 will be described.

  When image formation is started, the CPU 42 starts measurement of the printing rate for each color using each printing rate measurement sensor 40 in S501. The CPU 42 waits until the image forming operation ends in S502, and ends the measurement of the printing rate in S503 in response to the end of image forming. Thereafter, in step S504, the CPU 42 calculates the toner consumption amount used for the image formation executed this time for each cartridge 12 based on the measured printing ratio of each color. Further, in step S <b> 505, the CPU 42 calculates and updates the total toner consumption amount by adding the calculated toner consumption amount to the total toner consumption amount of each cartridge 12 stored in the RAM 44.

  Finally, in S <b> 506, the CPU 42 also stores the toner consumption amount of each cartridge 12 stored in the RAM 44 in the nonvolatile memory 45. As described above, the CPU 42 ends the measurement of the total toner consumption amount of each cartridge 12. When any one of the cartridges 12 is replaced, the total toner consumption value in the RAM 44 and the nonvolatile memory 45 corresponding to the replaced cartridge 12 is cleared to zero.

  Next, in step S303, when the CPU 42 stops the drive motor 32, the CPU 42 controls the photosensitive member 13 based on the total driving time of the photosensitive member 13 and the total toner consumption amount of the cartridge 12 measured in steps S301 and S302. Determine the startup order when starting from a stopped state. Specifically, the CPU 42 determines the remaining amount of toner in each cartridge 12 with respect to the remaining time during which the photosensitive member 13 can be driven until the cartridge 12 reaches the end of its life. The smaller the value, the higher the weight.

  As a result, the smaller the remaining amount of toner, the longer the remaining time for which the photosensitive member 13 can be driven (the remaining lifetime of the photosensitive member 13) is adjusted. As a result, the lower the toner remaining in the cartridge 12, the earlier the activation order determined for the photoconductor 13 of the cartridge 12. In this way, the photosensitive member 13 and the toner container 10 can be used in a well-balanced manner by preferentially using the photosensitive member 13 for the cartridge 12 with a small amount of remaining toner, that is, the cartridge 12 that is approaching the end of its life. To.

In the following, a specific example of weighting (adjustment) of the remaining life of the photoreceptor 13 based on the measured remaining toner amount (corresponding to the total toner consumption amount) will be described. First, the CPU 42 obtains the ratio between the remaining amount of toner and the remaining life of the photoreceptor 13 for each cartridge 12. First, the remaining life (ratio) of the photoreceptor 13 and the remaining amount (ratio) of toner are obtained for each cartridge 12 using the equations (1) and (2).
Residual Life of Photoreceptor 13 = (Total Design Drive Time Corresponding to Photoreceptor Life-Measured Total Drive Time)
/ Total driving time in design corresponding to the life of photoconductor (1)
Toner remaining amount = (total amount of toner in toner container 10−total amount of toner consumption measured)
/ Total amount of toner in toner container 10 (2)
Further, the CPU 42 obtains a ratio R between the remaining amount of toner and the remaining life of the photoreceptor 13 based on the calculation results of the equations (1) and (2) using the equation (3).
R = remaining life of photoconductor 13 / remaining toner (3)
In this way, for each cartridge 12, the remaining life of the photoconductor 13 estimated from the measured total drive time of the photoconductor 13 (that is, the remaining time during which the photoconductor 13 can be driven) is divided by the remaining amount of toner. As a result, the remaining life of the photoreceptor 13 is adjusted.

  The CPU 42 determines the activation order of the photoreceptors 13 included in the cartridge 12 in descending order of the ratio R based on the calculation result of the expression (3) for each cartridge 12. Similarly to the first embodiment, the CPU 42 further updates the data indicating the determined activation order stored in the RAM 44 and the nonvolatile memory 45 with the newly determined activation order.

  Note that the activation control for activating the stopped photoreceptors 13Y, 13M, 13C, and 13K may be performed in the activation order determined in S303 in the same manner as in the first embodiment.

  As described above, by determining the starting order of the photoconductors 13 as in the present embodiment, the remaining life of the photoconductors 13 and the remaining amount of toner in each cartridge 12 can be obtained as the image forming apparatus 100 is used. It will decrease in a balanced manner. That is, the photoconductor 13 is consumed in accordance with the usage state of the toner container 10, and the photoconductor 13 and the toner container 10 can be used in a well-balanced manner. As a result, even when the usage status of a plurality of parts included in each cartridge 12 can be biased, the photoconductor 13 can be consumed according to the usage status of other parts, and each part can be used effectively. .

  In this embodiment, the activation order of the photoconductors 13 is determined based on the ratio R of the remaining life of the photoconductors 13 to the remaining amount of toner. However, the method for determining the activation order is not limited to this. For example, even if the activation order is determined based on the difference value between the remaining amount of toner and the remaining life of the photosensitive member 13, the same effect as in the present embodiment can be obtained.

[Third Embodiment]
In the third embodiment, the remaining life of each photoconductor 13 is predicted based on the total average printing rate of each cartridge 12 in the determination control of the activation order of each photoconductor 13, and the photoconductor is used using the prediction result. 13 start orders are determined. In the following description, only parts different from the first and second embodiments will be described for simplification of description. For example, the configuration of the image forming apparatus 100 is the same as the configuration illustrated in FIG. 1 in the first embodiment. The control configuration of the image forming apparatus 100 is the same as that in the second embodiment (FIG. 14).

  In the second embodiment, the case where the printing rate is measured at the time of image formation and the activation order of the photosensitive members 13 is determined in consideration of the printing rate has been described. Here, the total average printing rate corresponding to the average value of the printing rate correlates with the toner consumption amount in each cartridge 12. Specifically, the toner consumption increases as the total average printing rate increases. Further, in consideration of the case where there is not much difference in the total driving time of each photoconductor of each photoconductor 13, as the toner consumption amount in the cartridge 12 increases, the toner container 10 may reach the end of its life before the photoconductor 13. It can be said that there is. That is, it can be said that the cartridge 12 having a high total average printing rate has a margin before the photosensitive member 13 reaches the end of its life, compared with the cartridge 12 having a low total average printing rate.

  Therefore, in the present embodiment, the remaining life of each photoconductor 13 is predicted as being longer as the total average print rate of each cartridge 12 is larger, so that the photoconductor included in the cartridge 12 is larger as the total average print rate is higher. The start order of 13 is advanced. As a result, the photoconductor 13 is consumed according to the usage state of the toner container 10, and the photoconductor 13 and the toner container 10 can be used in a well-balanced manner.

<Decision Control for Starting Order of Photoconductor 13>
FIG. 19 shows a part of data stored in the RAM 44 and used when the CPU 42 controls the driving of the photosensitive member 13. As in the first embodiment, the CPU 42 stores data indicating the first to fourth activated photoreceptors 13 in the RAM 44. In the present embodiment, the CPU 42 further determines the total number of image formations corresponding to the number of recording materials on which the image is formed after the cartridges are mounted on the image forming apparatus 100 for the cartridges 12Y, 12M, 12C, and 12K. The total average printing rate is also stored in the RAM 44.

  FIG. 20 is a flowchart showing a determination control procedure for determining the activation order of the photoreceptors 13 according to the present embodiment. The processing of each step shown in FIG. 20 is realized on the image forming apparatus 100 by the CPU 42 reading the control program stored in the ROM 43 into the RAM 44 and executing it. In this embodiment, it is assumed that image formation is performed for each recording material. That is, every time image formation is performed on one recording material, the CPU 42 updates the activation order of the photosensitive member 13 when the drive motor 32 is activated next time.

  First, when image formation is started, the CPU 42 starts measurement of the printing rate for each color using each printing rate measurement sensor 40 in S601. In step S602, the CPU 42 waits until the image forming operation is completed. In response to the completion of the image formation, the CPU 42 ends the measurement of the printing rate.

In step S <b> 604, the CPU 42 calculates a total average print rate for each cartridge 12 based on the measured print rate and the total number of formed images stored in the RAM 44. Here, the CPU 42 calculates the total average printing rate of each cartridge 12 using the equation (4).
Total average printing rate = ((total average printing rate x total number of images formed) + measured printing rate)
/ (Total number of images formed + 1) (4)
In step S <b> 605, the CPU 42 adds 1 to the total number of formed images stored in the RAM 44.

  Next, in S606 to S609, the CPU 42 determines an activation order for activating the stopped photoreceptors 13Y, 13M, 13C, and 13K based on the total average printing rate calculated using Expression (4). The data indicating the determined activation order is stored in the RAM 44. Specifically, the CPU 42 determines that the photoconductors 13Y, 13M, 13C, and 13K should be started in descending order of the measured total average printing rate (stored in the RAM 44).

  Finally, in S610, the CPU 42 also stores (updates) the total driving time of each photoconductor 13 stored in the RAM 44 in the nonvolatile memory 45. As in the first and second embodiments, the CPU 42 further updates the data indicating the determined activation order stored in the RAM 44 and the nonvolatile memory 45 with the newly determined activation order. When any one of the cartridges 12 is replaced, the values of the total average printing rate and the total number of formed images in the RAM 44 and the nonvolatile memory 45 corresponding to the replaced cartridge 12 are cleared to zero.

  As described above, in this embodiment, the remaining life of each photoconductor 13 is predicted to be longer as the total average print rate of each cartridge 12 is larger. The starting order of the included photoconductors 13 is made earlier. As a result, as in the second embodiment, the photoconductor 13 is consumed according to the usage status of the toner container 10, and the photoconductor 13 and the toner container 10 can be used in a well-balanced manner.

Claims (12)

An image forming apparatus,
A plurality of process units that are detachable from the main body of the image forming apparatus and have at least a photoconductor;
For each of the plurality of process units, a prediction unit that predicts a remaining time during which the photoconductor can be driven before the process unit reaches the end of life from information indicating a use status of the process unit;
And an deciding means for deciding an activation order when activating the stopped photoconductor included in the plurality of process units according to the remaining time predicted by the prediction means. Forming equipment.   2. The prediction unit predicts a remaining time during which the photosensitive member can be driven when driving of the photosensitive member included in the process unit is stopped according to the end of the image formation. The image forming apparatus described in 1.   3. The image forming apparatus according to claim 1, wherein the determination unit determines the activation order of the photoconductors in the descending order of the remaining time predicted by the prediction unit. The prediction means includes
For each of the plurality of process units, the total drive time of the photoconductor after the process unit is mounted on the main body of the image forming apparatus is measured, and the remaining time is predicted from the measured total drive time. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The prediction means includes
5. The difference between a predetermined total driving time corresponding to the life of the photosensitive member and the measured total driving time is predicted as the remaining time for each of the plurality of process units. Image forming apparatus. Each of the plurality of process units further includes a toner container storing toner for forming the image,
The predicting means further includes:
For each of the plurality of process units, the remaining time predicted from the measured total driving time is weighted so that the remaining time becomes longer as the remaining amount of toner contained in the toner container is smaller. The image forming apparatus according to claim 4, wherein: The prediction means includes
The image formation according to claim 6, wherein a value obtained by dividing the remaining time predicted from the measured total driving time by the remaining amount of toner is predicted for each of the plurality of process units. apparatus. Each of the plurality of process units further includes a toner container storing toner for forming the image,
The prediction means includes
For each of the plurality of process units, a printing rate indicating a ratio of an area occupied by the toner attached to the recording material by the image formation to an area of the recording material is measured, and the process unit is a main body of the image forming apparatus 4. The image forming apparatus according to claim 1, wherein the remaining time is predicted as a longer time as the average value of the printing rate after being attached to the printer is larger. 5. A selection means for selecting one of a plurality of predetermined stop positions as a stop position when stopping the photosensitive member included in each of the plurality of process units from a rotating state;
The image forming apparatus according to claim 1, further comprising a stop unit that stops the rotation of the photoconductor at a stop position selected by the selection unit.   The image according to claim 9, wherein the selection unit selects a stop position that can be stopped in the shortest time after the rotation speed of the photosensitive member is started to be reduced, among the plurality of stop positions. Forming equipment.   The image forming apparatus according to claim 9, wherein the selection unit randomly selects one of the plurality of stop positions. The apparatus further comprises start means for starting the stopped photoconductors in the order determined by the determination means so that the photoconductors included in the plurality of process units rotate at the same phase. Item 12. The image forming apparatus according to any one of Items 1 to 11.

Images