JP2006259069A - Image forming apparatus and adjustment method for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide appropriate adjusting operation sequence in accordance with the arrangement of a developing cartridge in an image forming apparatus equipped with a rotary developing unit. <P>SOLUTION: Of the developing units 4a, 4b and 4d which are arranged adjacently to each other on the rotary developing unit 4, the downstream-most developing unit 4d along the direction D4 of rotations of the rotary developing unit 4 is positioned first at a developing position and a patch image is formed. The rotary developing unit 4 then rotates 90 degrees, and the adjacent developing unit 4a is moved to the developing position. While the developing unit 4a forms a patch image, a memory of the developing unit 4b is updated. After this, while rotating the rotary developing unit 4 by 90 degrees each time, patch image formation with and memory update for the respective developing units 4a, 4b and 4d are carried out. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus including a rotary developing unit that can be mounted with a developing cartridge having a storage unit and rotatable in a predetermined direction, and an adjustment method for adjusting operating conditions of the apparatus in the apparatus. .

  Conventionally, in an image forming apparatus including a rotary developing unit capable of mounting a plurality of developing cartridges, an operation sequence has been established on the assumption that all the cartridges that can be mounted are mounted at predetermined positions. However, in recent years, in order to meet a wider range of user requirements, there is an apparatus capable of forming an image even when some of the developing cartridges are not installed or when the developing cartridges are installed in a different arrangement from the original arrangement. Has been proposed.

  For example, in the image forming apparatus described in Patent Document 1, when a development unit corresponding to a monochrome color is mounted among four development units (development cartridges) corresponding to four toner colors, the presence or absence of other units is present. Regardless of this, monochrome printing can be executed. Further, in the image forming apparatus described in Patent Document 2, monochrome image formation is possible in a state where a developing cartridge of the same color is attached to a developing rotary to which a developing cartridge of a different toner color should be originally attached.

Japanese Patent Laid-Open No. 2003-50495 (FIG. 6) JP 2002-351190 A (paragraph 0042)

  In this type of image forming apparatus, in order to appropriately manage the usage status of each developing cartridge, the developing cartridge may be provided with storage means (such as a memory) for storing information indicating the usage status of the cartridge. . The operation sequence in such an apparatus is configured such that the information stored in the storage means is updated after each developer cartridge is used. However, as described above, when the arrangement of the developing cartridge is irregular, such an operation sequence may not be optimal.

  In particular, in the adjustment operation of the operation condition of the apparatus that is performed at any time corresponding to each developing cartridge, the required time affects the throughput of image formation. Therefore, in order to improve the throughput, the arrangement of the developing cartridge at that time is required. It is desirable that an optimal operation sequence is executed. However, such an operation sequence has not been studied in detail conventionally.

  The present invention has been made in view of the above problems, and an object thereof is to provide an appropriate adjustment operation sequence according to the arrangement of the developing cartridge in an image forming apparatus including a rotary developing unit.

  In order to achieve the above object, the image forming apparatus according to the present invention is configured to be capable of mounting N developing cartridges (N is an integer of 3 or more) including storage means for storing information relating to the usage status of the developing cartridge. A rotary developing unit rotatable in a predetermined direction; an image forming operation for forming a toner image using a developing cartridge positioned at a predetermined developing position among the developing cartridges mounted on the rotary developing unit; Control means for executing an update operation for accessing the storage means provided in the developing cartridge positioned at the access position and updating the stored contents, wherein the development position and the access position are the rotary development unit. Of the two developing cartridges mounted at positions adjacent to each other above, the rotary Positional relationship such that when one developing cartridge positioned upstream in the rotation direction of the developing unit is positioned at the developing position, the other developing cartridge of the two developing cartridges is positioned at the access position. The control means executes the image forming operation using a developing cartridge mounted on the rotary developing unit, forms a toner image as a patch image, and detects the density of the patch image. Based on the result, an adjustment operation for adjusting an operation condition when the developing cartridge is used for the image forming operation is further executed, and M pieces mounted adjacently on the rotary developing unit. When the adjustment operation is performed for a developing cartridge (M is an integer of 2 or more and less than N), Among the M developing cartridges, the patches are sequentially positioned at the developing position while switching the developing cartridge from the developing cartridge located at the most downstream side in the rotation direction of the rotary developing unit toward the developing cartridge located at the most upstream side. An image is formed, and the update operation is performed on the developing cartridge positioned at the access position after the patch image is formed.

  In the invention thus configured, the development cartridge mounted on the most downstream side in the rotation direction of the rotary development unit is positioned at the development position to form a patch image, and then the development cartridge mounted on the most upstream side is developed. The amount of rotation of the rotary developing unit until it is positioned can be minimized. Therefore, the developing cartridge can be switched in a short time. In addition, the rotation of the rotary developing unit by a predetermined amount enables the positioning of the developing cartridge that has finished forming the patch image to the access position and the positioning of the next developing cartridge to the developing position at the same time. The required time can be shortened. It should be noted that the patch image formation using one developing cartridge and the update operation for the other developing cartridge can be executed at arbitrary timings within a period in which the rotary developing unit is stopped at the same position.

  Here, as the information to be stored in the storage unit, for example, the total operation time of the developing cartridge, the remaining amount of toner, and the like can be used. These pieces of information indicate the degree of consumption of the developing cartridge. By managing these information, the life management of the developing cartridge can be appropriately performed. Further, the operation parameters of each part of the apparatus corresponding to the developing cartridge obtained as a result of the adjustment operation may be stored. By storing these information in the storage means provided in the developing cartridge, even when the developing cartridge is removed, the information regarding the developing cartridge is attached to the developing cartridge, and once removed from the apparatus main body, Even if the developing cartridge is used in another apparatus, the life management thereof can be appropriately performed.

  Here, the control means forms a patch image using the developing cartridge newly positioned at the developing position by switching the developing cartridge, and updates the developing cartridge newly positioned at the access position by the switching. The operation may be executed in parallel with the operation. Thus, after the formation of the patch image using one developing cartridge is completed and the developing cartridge is switched, the patch image is formed for the next developing cartridge, while the storage means is used for the previous developing cartridge. Since the information can be updated, the adjustment operation can be performed more efficiently.

  By the way, when the adjustment operation is performed in the operation sequence as described above, the last used one, that is, the most upstream one of the M developing cartridges is stopped at the access position after the patch image is formed. There is no timing, and the information in the storage means cannot be updated. Therefore, the control unit forms the patch image using the developing cartridge that is located on the most upstream side in the rotation direction of the rotary developing unit among the M developing cartridges, and then moves the developing cartridge to the access position. It may be configured to perform the update operation by moving to. By doing so, the information stored in the storage unit can be updated for all of the M developing cartridges. Even in this case, the time required to move the developing cartridge last used for patch image formation from the developing position to the access position is short.

  Further, in an image forming apparatus that is used in a state in which a developing cartridge storing the same color toner is attached to a full-color image forming apparatus that must have all necessary toner colors, the attached developing cartridge is Any number of images can be formed. Therefore, in this type of apparatus, it is convenient for the user if an image can be formed with only a part of the mountable developing cartridge mounted. The adjustment operation sequence constructed according to the present invention can be preferably applied to such an apparatus. In other words, the present invention is particularly effective when the M developing cartridges store toners of the same color. Even in an apparatus equipped with a plurality of developing cartridges that store different color toners, the operation sequence according to the present invention can be applied when an adjustment operation is performed on some of the developing cartridges.

  The adjustment method of the image forming apparatus according to the present invention is configured so that N developing cartridges (N is an integer of 3 or more) including a storage unit that stores information on the usage status of the developing cartridge can be mounted. In an adjustment method of an image forming apparatus including a rotary developing unit that is rotatable in a direction, in order to achieve the above object, M (M is an integer less than or equal to 2 and less than N) mounted adjacently on the rotary developing unit. For each of the developing cartridges, the developing cartridge is positioned at a predetermined developing position, and a toner image as a patch image is formed using the developing cartridge, and the density of the patch image is detected. Based on the result, the operating condition of the apparatus when the toner cartridge is formed using the developing cartridge is adjusted. An adjustment step and an update step of accessing the storage means provided in the developing cartridge and updating the stored contents, and among the M developing devices, the update step is the most in the rotation direction of the rotary developing unit. When the patch image forming step is executed in order while switching the developing cartridge from the developing cartridge located on the downstream side toward the developing cartridge located on the most upstream side, and one developing cartridge is positioned at the developing position In addition, the updating step is performed on the developing cartridge adjacent to the downstream side in the rotation direction of the rotary developing unit as viewed from the developing cartridge.

  In the invention configured as described above, the operating conditions of the apparatus can be adjusted efficiently in a short time as in the above-described invention relating to the image forming apparatus.

  FIG. 1 is a view showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus of FIG. This apparatus forms a full color image by superposing four color toners (developers) of yellow (Y), cyan (C), magenta (M), and black (K), or only black (K) toner. The image forming apparatus forms a monochrome image using In this image forming apparatus 1, when an image signal is given to the main controller 11 from an external device such as a host computer, the engine controller 10 that functions as a “control unit” of the present invention is in response to a command from the main controller 11. A predetermined image forming operation is executed by controlling each part of the engine unit EG, and an image corresponding to the image signal is formed on the sheet S.

  In the engine unit EG, the photosensitive member 22 is provided to be rotatable in the arrow direction D1 in FIG. A charging unit 23, a rotary developing unit 4 and a cleaning unit 25 are arranged around the photosensitive member 22 along the rotation direction D1. The charging unit 23 is applied with a predetermined charging bias, and uniformly charges the outer peripheral surface of the photoconductor 22 to a predetermined surface potential. The cleaning unit 25 removes the toner remaining on the surface of the photosensitive member 22 after the primary transfer, and collects it in a waste toner tank provided inside. The photosensitive member 22, the charging unit 23, and the cleaning unit 25 integrally constitute the photosensitive member cartridge 2, and the photosensitive member cartridge 2 is detachably attached to the apparatus main body as a whole.

  Then, the light beam L is irradiated from the exposure unit 6 toward the outer peripheral surface of the photosensitive member 22 charged by the charging unit 23. The exposure unit 6 exposes the light beam L onto the photoconductor 22 in accordance with an image signal given from an external device to form an electrostatic latent image corresponding to the image signal.

  The electrostatic latent image thus formed is developed with toner by the developing unit 4. That is, in this embodiment, the developing unit 4 is a support frame 40 that is rotatably provided in a direction D4 in FIG. 1 around a rotation axis orthogonal to the paper surface of FIG. A yellow developing device 4Y, a cyan developing device 4C, a magenta developing device 4M, and a black developing device 4K, each of which is configured to contain toner of each color, are provided. The developing unit 4 is controlled by the engine controller 10. Based on the control command from the engine controller 10, the developing unit 4 is driven to rotate, and the developing units 4Y, 4C, 4M, and 4K are selectively brought into contact with the photoreceptor 22 or have a predetermined gap. When positioned at a predetermined developing position facing each other, the photosensitive member 22 is provided from the metal developing roller 44 which is provided in the developing unit and carries charged toner of a selected color and to which a predetermined developing bias is applied. Toner is applied to the surface. As a result, the electrostatic latent image on the photosensitive member 22 is visualized with the selected toner color.

  Each of the developing devices 4Y, 4C, 4M, and 4K includes nonvolatile memories 91 to 94 for storing information related to the developing devices, and wireless communication antennas 49Y, 49C, and 49M that are electrically connected to the memories, and 49K. In addition, a wireless communication antenna 109 connected to the CPU 101 via the transceiver 105 is provided in the vicinity of the outer peripheral portion of the rotary developing unit 4 on the apparatus main body side. Then, the rotary developing unit 4 is positioned so that one of the antennas 49Y, 49C, 49M, and 49K provided in each developing device is arranged close to the antenna 109 provided on the main body side. Then, wireless communication is performed between the CPU 101 of the engine controller 10 and the memories 91 to 94. In this way, information about each developing device is transmitted to the CPU 101, and information in each of the memories 91 to 94 is updated and stored.

  The toner image developed by the developing unit 4 as described above is primarily transferred onto the intermediate transfer belt 71 of the transfer unit 7 in the primary transfer region TR1. The transfer unit 7 includes an intermediate transfer belt 71 stretched between a plurality of rollers 72 to 75, and a drive unit (not shown) that rotates the intermediate transfer belt 71 in a predetermined rotation direction D2 by rotationally driving the roller 73. It has. When a color image is transferred to the sheet S, each color toner image formed on the photosensitive member 22 is superimposed on the intermediate transfer belt 71 to form a color image and taken out from the cassette 8 one by one. Then, the color image is secondarily transferred onto the sheet S conveyed along the conveyance path F to the secondary transfer region TR2.

  At this time, in order to correctly transfer the image on the intermediate transfer belt 71 to a predetermined position on the sheet S, the timing of feeding the sheet S to the secondary transfer region TR2 is managed. Specifically, a gate roller 81 is provided on the transport path F on the front side of the secondary transfer region TR2, and the gate roller 81 rotates in accordance with the timing of the circumferential movement of the intermediate transfer belt 71. S is sent to the secondary transfer region TR2 at a predetermined timing.

  Further, the sheet S on which the color image is thus formed is conveyed to the discharge tray portion 89 provided on the upper surface portion of the apparatus main body via the fixing unit 9, the pre-discharge roller 82 and the discharge roller 83. Further, when images are formed on both sides of the sheet S, when the rear end portion of the sheet S on which the image is formed on one side as described above is conveyed to the reversal position PR behind the pre-discharge roller 82. The rotation direction of the discharge roller 83 is reversed, whereby the sheet S is conveyed in the direction of the arrow D3 along the reverse conveyance path FR. Then, the sheet is again placed on the transport path F before the gate roller 81. At this time, the surface of the sheet S to which the image is transferred by contacting the intermediate transfer belt 71 in the secondary transfer region TR2 is first transferred. It is the opposite surface. In this way, images can be formed on both sides of the sheet S.

  In addition, as shown in FIG. 2, this apparatus includes a display unit 12 that is controlled by the CPU 111 of the main controller 11. The display unit 12 is constituted by, for example, a liquid crystal display, and in accordance with a control command from the CPU 111, the operation guidance to the user, the progress of the image forming operation, the occurrence of an abnormality in the apparatus, the replacement time of any unit, etc. A predetermined message for notification is displayed.

  In FIG. 2, reference numeral 113 denotes an image memory provided in the main controller 11 for storing an image given from an external device such as a host computer via the interface 112. Reference numeral 106 is a ROM for storing a calculation program executed by the CPU 101, control data for controlling the engine unit EG, and the like. Reference numeral 107 is a RAM for temporarily storing calculation results in the CPU 101 and other data. is there.

  A cleaner 76 is disposed in the vicinity of the roller 75. The cleaner 76 can be moved toward and away from the roller 75 by an electromagnetic clutch (not shown). Then, the blade of the cleaner 76 abuts on the surface of the intermediate transfer belt 71 that is stretched over the roller 75 while moving to the roller 75 side, and the toner that remains on the outer peripheral surface of the intermediate transfer belt 71 after the secondary transfer. Remove.

  Further, a density sensor 60 is disposed in the vicinity of the roller 75. The density sensor 60 is provided to face the surface of the intermediate transfer belt 71 and measures the image density of the toner image formed on the outer peripheral surface of the intermediate transfer belt 71 as necessary. Based on the measurement results, this apparatus uses the operating conditions of each part of the apparatus that affect the image quality, such as the developing bias applied to each developing device, the intensity of the exposure beam L, and the tone correction characteristics of the apparatus. Adjustments are being made.

  The density sensor 60 is configured to output a signal corresponding to the density of a predetermined area on the intermediate transfer belt 71 using, for example, a reflective photosensor. The CPU 101 can detect the image density of each part of the toner image on the intermediate transfer belt 71 by periodically sampling the output signal from the density sensor 60 while rotating the intermediate transfer belt 71.

  The image forming apparatus configured as described above is an apparatus capable of forming a full-color image, but also functions as a monochrome-only machine that forms only a monochrome image at the request of the user. That is, in this apparatus, instead of the four developing devices corresponding to the Y, M, C, and K toner colors, only one developing device or two or more developing devices of the same toner color are arranged in the rotary developing unit 4. The image forming operation with the toner color can be performed in the state of being attached to the printer. Therefore, in the following, the toner colors of the developing devices mounted on the rotary developing unit 4 are not particularly distinguished, and the four developing devices are represented by reference numerals 4a, 4b, 4c, and 4d in accordance with the order of use. Each developing device is used in order along the rotation direction D4 of the rotary developing unit 4, and is switched to a developing device located upstream one of the currently used developing devices as necessary. Shall. In this way, switching of the developing device in the image forming operation can be performed only by rotating the rotary developing unit 4 by 90 degrees in the rotation direction. However, which developing unit is to be used first is determined in advance. Here, the developing device 4a is used first, but is not limited to this.

  FIG. 3 is a diagram showing a stop position of the rotary developing unit. As shown in FIG. 3, the rotary developing unit 4 can be positioned and stopped at (a) the home position and (b) the image forming position. FIG. 3B shows an example of the image forming positions. Actually, there are four image forming positions corresponding to each of the four developing devices and having angles different from each other by 90 degrees. To do. Among these, the home position is a standby position of the rotary developing unit 4 when no image signal is given to the apparatus. At this home position, as shown in FIG. 3A, the developing rollers 44a, 44b, 44c and 44d provided in the developing units are all separated from the photosensitive member 22.

  In the state where the rotary developing unit 4 is stopped at the image forming position, the developing roller 44a provided in one of the developing devices (the developing device 4a in the example of FIG. 3B) is connected to the photosensitive member 22. Opposed. In this state, the electrostatic latent image formed on the surface of the photoconductor 22 can be visualized with the toner stored in the developing device 4a (image forming operation). That is, the position of the developing device 4a in FIG. 3B corresponds to the “developing position” in the present invention.

  On the other hand, in the developing device 4d that is one downstream of the developing device 4a in the rotation direction of the rotary developing unit 4, the antenna 49d provided in the developing device 4d is disposed opposite to the main body side antenna 109. Become. Therefore, it becomes possible to access the memory provided in the developing device 4d by wireless communication from the CPU 101. In this state, information on the usage status of the developing device stored in the memory is updated (update operation). That is, the position of the developing device 4d in FIG. 3B corresponds to the “access position” in the present invention.

  As described above, the developing position and the access position are arranged so that the other developing device is positioned at the access position in a state where the developing device mounted on the rotary developing unit 4 is positioned at the developing position. Thus, while the image forming operation is executed on the one hand, the memory update operation can be executed on the other hand simultaneously, and the processing time can be shortened.

  FIG. 4 is a diagram showing an operation sequence of the full-color image forming operation. More specifically, it is a schematic diagram showing the rotational movement and stop position of the rotary developing unit 4 in the image forming operation. In the full color image forming operation, the rotary developing unit 4 is first rotated 135 degrees from the home position. In this state, an image forming operation is performed by the developing device 4a positioned at the developing position. Next, the rotary developing unit 4 is rotated 90 degrees. In this state, the developing device 4a is positioned at the access position, and the developing device 4b is positioned at the developing position. Then, the updating operation of the developing device 4a and the image forming operation of the developing device 4b are performed in parallel. Similarly, while rotating the rotary developing unit 4 by 90 degrees, the updating operation of the developing device 4b and the image forming operation of the developing device 4c, and the updating operation of the developing device 4c and the image forming operation of the developing device 4d are performed in parallel. . Further, the rotary developing unit 4 is rotated 90 degrees, the developing unit 4d is positioned at the access position, the updating operation is performed, and then the home position is returned again.

  As described above, since the development position and the access position are provided at positions shifted by 90 degrees, in the full-color image forming operation using all the developing devices, the updating operation is performed on the developing device that has performed the image forming operation first. At the same time, the image forming operation can be executed for the developing device mounted on the upstream side one by one, and the time required for the entire processing is shortened.

  Next, the density control operation in this image forming apparatus will be described. This density control operation forms a toner image as a patch image, and controls the image density to a target density by adjusting the operating conditions (development bias, exposure power, etc.) of each part of the apparatus based on the density detection result. Is the processing operation. This density control operation is executed in a state where at least one developing device is mounted on the support frame 40. Further, it can be executed only for a part of the developing devices mounted on the support frame 40.

  When the density control operation is executed for all four developing devices, the processing can be performed by the same operation sequence as the full-color image forming operation described above. However, when the number of developing devices to be subjected to the density control operation is a part of the four, it may not be said that such an operation sequence functions effectively. In the following, a description will be given of an operation sequence suitable for the case where the density control operation is performed on three developing devices mounted on the support frame 40 and two adjacent developing devices. As will be described later, this operation sequence includes four operation sequences. The present invention can also be applied to the case where the density control operation is performed for each developing device.

  FIG. 5 is a flowchart showing the density control operation. In this density control operation, first, the developing unit located adjacent to the upstream side as viewed from the most downstream developing unit in the rotation direction D4 of the developing unit 4 is moved to the developing position (step S101). For example, when the density control operation is performed on the three developing devices 4a, 4b, and 4c, the developing device 4b located in the middle of them corresponds to this. Further, when the density control operation is performed on the two developing devices 4a and 4b adjacent to each other, the developing device 4b located on the upstream side of them corresponds to this. In the case where the density control operation is performed on the four developing devices, the developing device 4a may be handled as the most downstream developing device in the order of use.

  Next, a rotating operation is performed to rotate the developing roller provided in the developing device at the developing position by a predetermined amount (step S102). This rounding operation is performed in order to prevent density unevenness that occurs when an image is formed using toner left on the surface of the developing roller from appearing in a patch image to be formed later. By rotating the developing roller prior to image formation, fresh toner is supplied to the surface of the developing roller, and density unevenness is suppressed. At this time, in order to prevent the toner from scattering from the developing roller, it is desirable not to apply a developing bias or to set a potential different from that at the time of image formation.

  Then, it is determined whether there is another developing device subject to the density control operation at a position adjacent to the upstream side of the developing device currently in the developing position (step S103). Then, the developing unit 4 is rotated 90 degrees to switch the developing device (step S104), and the developing roller is rotated in the same manner for the developing device newly positioned at the developing position. Thus, the circulation operation is performed for the developing devices that are the target of the density control operation except for the developing device located on the most downstream side. Further, by rotating the developing unit 4 in this way, the toner in each developing device is agitated and made uniform before the formation of the patch image. The reason why the circulation operation for the developing device located on the most downstream side is omitted will be described later.

  Subsequently, a developing bias adjustment process for obtaining a developing bias value and an exposure power value when performing image formation using the developing device with respect to the developing device subjected to the density control operation (step S105, FIG. 6) and the exposure power adjustment process (step S106, FIG. 7) are successively executed. After the completion, the developing unit 4 is returned to the home position and the process is ended (step S107).

  FIG. 6 is a flowchart showing the developing bias adjustment process. In this processing, first, among the developing devices to be subjected to the density control operation, the developing device located on the most downstream side in the rotation direction D4 of the developing unit 4 is positioned at the developing position (step S201). Then, a rotating operation is performed on the developing device (step S202), and subsequently, a patch image of a predetermined pattern (for example, a solid image) is formed with each bias value while changing and setting the magnitude of the developing bias in multiple stages. (Step S203). As described above, with respect to the developing device used for the patch image formation first, the rotation operation is performed immediately before the patch image formation, thereby reducing the number of movements of the developing unit 4 and shortening the processing time. This is the reason why the circulation operation was not performed for the most downstream developer in the operation of FIG.

  Next, the density of each formed patch image is detected by the density sensor 60 (step S204), and based on the density detection results, an optimum value of the developing bias at which the image density becomes a predetermined target density is calculated (step S204). Step S205). Since there are many known techniques for calculating the optimum developing bias value, detailed description thereof is omitted here.

  It is determined whether or not the above processing has been completed for all the developing devices subject to the density control operation (step S206). If there is an unexecuted developing device, the developing unit 4 is rotated 90 degrees. After switching the developing device (step S207), the above processing is repeatedly executed. In addition, since the circulation operation | movement about another developing device is already complete | finished, it does not perform here. Subsequently, the exposure power is adjusted.

  FIG. 7 is a flowchart showing the exposure power adjustment process. In this process, the developing device located on the most downstream side in the rotation direction of the developing unit 4 is moved again to the developing position (step S301). Then, while changing and setting the power of the light beam L from the exposure unit 6 in multiple stages, a patch image of a predetermined pattern (for example, a halftone image) is formed with each exposure power (step S302).

  In parallel with the formation of the patch image, the information stored in the memory provided in the developing device is updated for the developing device located at the access position at that time (step S303). Since there is no developing device at the access position at this time or there is a developing device that is not the target of density control operation, the memory update (step S303) at this time may be omitted.

  Following the formation of the patch image, as in the development bias adjustment process, the density of each patch image is detected by the density sensor 60 (step S304), and the optimum exposure power is calculated based on the detection result (step S305). By repeating the above processing while switching the developing device (step S307) until the processing is completed for all the developing devices subject to the density control operation (step S306), the optimum value of the exposure power for each developing device is obtained. Desired. When the processing is completed for all necessary developing devices, the developing unit 4 is further rotated 90 degrees (step S308). As a result, the developing unit used for the last patch image formation, that is, the developing unit positioned at the most upstream side in the rotation direction of the developing unit 4 in the arrangement of the developing units to be subjected to the density control operation is positioned at the access position. . In this state, after updating the memory of the developing device, the process is terminated (step S309).

  By performing the density control operation configured as described above, an optimum developing bias and optimum exposure power are obtained for each developing device. By applying the optimum value thus obtained, an image can be formed with a predetermined target density in the subsequent image forming operation. In this density control operation, a patch image is formed by sequentially positioning the developing devices to be subjected to the density control operation from the position located on the most downstream side in the rotation direction of the developing unit 4 at the developing position. Therefore, as in the operation sequence in the case of the full-color image forming operation described above, all the necessary developing devices are sequentially moved to the developing position by simply rotating the developing unit 4 by 90 degrees each time patch image formation is completed. Can be positioned. Therefore, it is possible to switch the developing devices in a short time, and the density control operation can be completed in a short time.

  Note that, from the viewpoint of simply reducing the switching frequency of the developing devices, the developing bias adjustment and the exposure power adjustment may be continuously performed for one developing device. However, this is not the case in this embodiment. The reason is as follows. The patch image formation when adjusting the exposure power is preferably performed with the development bias set to the optimum value. For this purpose, the development bias is already set at the start of the formation of the patch image for adjusting the exposure power. The optimal value of must be determined. It takes a certain amount of processing time to form a patch image in development bias adjustment processing, detect its density, and calculate the optimal development bias based on the density detection result, and form a patch image for adjusting exposure power until the processing is completed. Can not do it. As a result, even if the development bias adjustment process and the exposure power adjustment process are continuously performed, the overall processing time is not necessarily shortened. Therefore, in this embodiment, a wasteful waiting time is not generated by executing the development bias adjustment process for the other developer unit between the development bias adjustment process and the exposure power adjustment process for one developer unit. In addition, by adopting an operation sequence that minimizes the time required for switching between developing devices, the processing can be completed in a short time.

  Further, in the exposure power adjustment processing, the information content in the memory is updated for the developing device that has finished forming the patch image and has moved from the development position to the access position. In this embodiment, information including at least the remaining amount of toner in the developing device and the total operation time of the developing roller, which is a parameter indicating the degree of deterioration of the developing device and the built-in toner, is stored in a memory in each developing device. ing. Since these values change due to the execution of the density control operation, it is possible to appropriately manage the life of the developing device by updating and storing the latest values in the memory. Further, the values of the optimum development bias and the optimum exposure power obtained as a result of the development bias adjustment process and the exposure power adjustment process may be stored. The reason why the memory is not updated when the development bias adjustment process is executed is that it is known that it is necessary to update again at that time because the exposure power adjustment process is subsequently performed.

  In addition, since the patch image is formed in order from the most downstream developing device in the rotation direction of the developing unit 4 and the processing is finished in the most upstream developing device, one development that has finished forming the patch image. When the developing device is moved from the developing position to the access position, the developing device for forming the patch image is inevitably moved to the developing position. Therefore, it is possible to minimize the rotation amount and frequency of the developing unit 4 necessary for sequentially moving the developing devices to the developing position and the access position, and to shorten the processing time. In addition, while performing the patch image formation using the developing device at the developing position, it is possible to update the memory for the developing device at the access position at the same time, thereby further improving the processing efficiency of the density control operation. .

  Note that the developing unit used for the last patch image formation must be moved to the access position in order to update the memory information after the completion. In this embodiment, since the position 90 degrees downstream of the developing position in the rotation direction D4 of the developing unit 4 is set as the access position, the rotating amount of the developing unit 4 in this case is only 90 degrees.

  In this way, the rotation operation of the developing unit 4 is always 90 degrees from the start of patch image formation for the first developer to the time when the memory is updated for the last developer. Therefore, not only the time required for switching is shortened, but also the rotational drive control of the developing unit 4 can be simplified.

  FIG. 8 is a diagram showing the movement of the developing unit in the density control operation for the three developing devices. FIG. 8 and FIGS. 9 and 10 described later show how the developing unit 4 rotates from the start time of the exposure power adjustment process to the end thereof. FIG. 8 illustrates the case where the density control operation is performed on the three developing devices 4a, 4b, and 4d. In this case, the original order of use along the operation sequence of the full-color image forming operation is the order of the developing devices 4a, 4b, and 4d. However, in the density control operation of this embodiment, the developing unit 4 is downstream in the rotation direction D4. Since they are used in order from the side, the order of use is the order of the developing devices 4d, 4a, and 4b.

  As shown in FIG. 8, at the time when the exposure power adjustment process is started, the developing unit 4 is stopped in a state where the developing device 4b used for forming the patch image is at the developing position. In order to move the most downstream developing device 4d from this state to the developing position, the developing unit 4 is rotated 180 degrees. In this state, after the patch image is formed using the developing device 4d, the development unit 4 is rotated by 90 degrees, and each time the memory is updated for the previous developing device and the patch image is formed by the next developing device. And in parallel. In addition, after the patch image is formed on the last (most upstream) developing device 4b, the developing unit 4 is further rotated 90 degrees to move the developing device 4b to the access position and update the memory.

  9 and 10 are diagrams showing the movement of the developing unit in the density control operation for two developing devices. 9 shows the movement of the developing unit 4 when the density control operation is performed for the two developing devices 4a and 4b, and FIG. 10 shows the development unit when the density control operation is performed for the two developing devices 4a and 4d. 4 movements are shown respectively. In the example of FIG. 9, since the developing device 4a is disposed on the downstream side and the developing device 4b is disposed on the upstream side, the use order in the density control operation is the same as the use order in the full-color image forming operation. That is, in this case, the formation of the patch image is started from the developing device 4a, and the information content in the memory of the developing device 4a is updated while the developing device 4b is moved to the developing position and the patch image is formed.

  On the other hand, in the example of FIG. 10, since the developing device 4d is arranged on the downstream side and the developing device 4a is arranged on the upstream side, in the density control operation, not the developing device 4a that is used first in the full-color image forming operation. The patch image formation is started from the developing device 4d on the downstream side. As described above, by executing the density control operation in the order based on the relative positional relationship between the developing devices to be subjected to the density control operation, the subsequent development unit 4 can be rotated by 90 degrees. As described above, in any of the cases shown in FIGS. 8 to 10, the rotation amount of the developing unit 4 required for switching the developing device from the start of patch image formation by the first developing device to the end of the last memory update. Is always 90 degrees. For this reason, the developing devices can be switched in a short time, and the rotation control of the developing unit 4 is easy.

  In the embodiment described above, the engine controller 10 functions as the “control means” of the present invention. The developing devices 4a, 4K, etc. correspond to the “developing cartridge” of the present invention. Further, the density control operation in the above embodiment corresponds to the “adjustment operation” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the image forming apparatus includes the developing unit 4 to which up to four developing devices can be mounted. However, the present invention is not limited to this, and the apparatus can be mounted with three or more developing devices. The present invention can be applied to the present invention.

  In the above-described embodiment, the rotation operation of the developing roller provided in each developing device is performed prior to the formation of the patch image, but such an operation is not essential in the present invention. In the density control operation of the above embodiment, the developing bias and the exposure power are adjusted as parameters related to the operating conditions of the apparatus. However, various types of parameters other than the above are known as this type of parameter, and there are many known techniques for density control techniques using them. For devices using such density control techniques, The present invention can also be applied.

  Further, for example, in the above embodiment, the memory contents are read and written by performing wireless communication between the memory provided in each developing device and the CPU 101, but between the apparatus main body and the developing device. You may connect with a connector and you may comprise so that reading / writing may be performed by wired communication.

  The present invention can be applied to both a full-color image forming apparatus equipped with a developer that stores toners of different colors and a monochrome image forming apparatus equipped with a developer that stores toner of a single color. Although possible, it has a remarkable effect especially in the latter case. This is because, in order to form a full color image, all the toner color developing devices must be prepared, whereas in a monochrome image forming apparatus, an image is formed if there is at least one developing device. This is because it is highly possible that only a part of the developing devices are mounted. Further, by permitting the image forming operation in such a state, it is possible to improve the convenience of the apparatus as seen by the user.

  In the above embodiment, four toner colors of yellow (Y), cyan (C), magenta (M), and black (K) are used. However, the number and types of toner colors are limited to this. It is not something. The present invention can also be applied to an apparatus provided with a plurality of developing devices of the same toner color. Furthermore, the present invention is not limited to the printer as in the above-described embodiment, and can be applied to other image forming apparatuses such as a copying machine and a facsimile machine.

1 is a diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus in FIG. 1. The figure which shows the stop position of a rotary image development unit. The figure which shows the operation | movement sequence of full color image formation operation | movement. The flowchart which shows density | concentration control operation | movement. 7 is a flowchart showing development bias adjustment processing. The flowchart which shows exposure power adjustment processing. FIG. 10 is a diagram illustrating the movement of a developing unit in a density control operation for three developing devices. FIG. 6 is a diagram illustrating a movement of a developing unit in a density control operation for two developing devices. FIG. 10 is a diagram illustrating another example of density control operation for two developing devices.

Explanation of symbols

  4 ... Rotary developing unit, 4a to 4d, 4C, 4K, 4M, 4Y ... Developing device (developing cartridge), 10 ... Engine controller (control means)

Claims (5)

A rotary developing unit configured to be capable of mounting N (N is an integer of 3 or more) developing cartridges having storage means for storing information about the usage status of the developing cartridge, and rotatable in a predetermined direction;
Of the developing cartridges mounted on the rotary developing unit, an image forming operation for forming a toner image using a developing cartridge positioned at a predetermined developing position and a developing cartridge positioned at a predetermined access position are provided. Control means for accessing the storage means and executing an update operation for updating the stored contents,
As for the development position and the access position, of the two development cartridges mounted at positions adjacent to each other on the rotary development unit, one development cartridge located upstream in the rotation direction of the rotary development unit is the development position. One of the two developing cartridges is positioned in a positional relationship such that the other developing cartridge is positioned at the access position when positioned at the position,
The control means includes
The image forming operation is executed using a developing cartridge attached to the rotary developing unit to form a toner image as a patch image, and the image forming operation is performed based on the density detection result of the patch image. An adjustment operation for adjusting an operation condition when using the developing cartridge is further executed,
When the adjustment operation is performed on M (M is an integer less than or equal to 2 and less than N) developing cartridges mounted adjacent to each other on the rotary developing unit, the rotational direction of the rotary developing unit among the M developing cartridges The patch image is formed by switching the developing cartridge from the developing cartridge located on the most downstream side to the developing cartridge located on the most upstream side in order to position the developing cartridge in the developing position, and the access is performed after the patch image is formed. An image forming apparatus that performs the updating operation on a developing cartridge positioned at a position.   The control means performs formation of a patch image using the development cartridge newly positioned at the development position by switching the development cartridge, and the update operation for the development cartridge newly positioned at the access position by the switching. The image forming apparatus according to claim 1, wherein the image forming apparatus is executed in parallel.   The control unit moves the developing cartridge to the access position after forming the patch image using the developing cartridge that is located on the most upstream side in the rotation direction of the rotary developing unit among the M developing cartridges. The image forming apparatus according to claim 1, wherein the update operation is performed.   The image forming apparatus according to claim 1, wherein the M developing cartridges store toners of the same color. An image forming apparatus including a rotary developing unit that is configured to be capable of mounting N developing cartridges (N is an integer of 3 or more) including a storage unit that stores information on the usage status of the developing cartridge, and is rotatable in a predetermined direction. In the adjustment method,
For each of M (M is an integer less than or equal to 2 and less than N) developer cartridges mounted next to each other on the rotary developing unit,
A patch image forming step of positioning the developing cartridge at a predetermined developing position and forming a toner image as a patch image using the developing cartridge;
An adjustment step of detecting the density of the patch image and adjusting the operating conditions of the apparatus when forming a toner image using the developing cartridge based on the result;
Performing an updating step of accessing the storage means provided in the developing cartridge and updating the stored contents;
The patch image forming process is executed in order while switching the developing cartridge from the developing cartridge located on the most downstream side in the rotation direction of the rotary developing unit to the developing cartridge located on the most upstream side among the M developing devices. And
An adjustment characterized in that, when one developing cartridge is positioned at the developing position, the updating step is performed on a developing cartridge adjacent to the downstream side in the rotation direction of the rotary developing unit as viewed from the developing cartridge. Method.

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