JP2008089795A - Image forming apparatus and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong, according to user's request, a period from the time when a near end state is detected till the time when a waste developer container becomes full of waste developer, in an image forming apparatus that performs an image forming operation for forming an image on an image carrier with developer and removes and recovers residual developer on the image carrier as waste developer, and in a control method for the apparatus. <P>SOLUTION: A user is allowed to set a mode relating to the execution of a patch process after the detection of a near end state. By setting a patch process reduction mode, the number of times that the patch process is executed is allowed to be decreased after the detection of the near end state (steps S23 to S28). During the setting of the patch process reduction mode, the number of times that the patch process is executed is restrained. This restrains a quantity of waste toner from increasing in a waste toner tank. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  An image forming apparatus that executes an image forming operation for forming an image on an image carrier using a developer, removes the developer remaining on the image carrier, and collects the developer as a waste developer. The present invention relates to a method for controlling the apparatus.

  2. Description of the Related Art Conventionally, an apparatus that forms an image using a developer such as toner is known. For example, in the apparatus described in Patent Document 1, a plurality of color toner images are sequentially formed on a photoconductor, and each toner image of each color is primarily transferred to an intermediate transfer medium, thereby superimposing the plurality of color toner images. A color toner image is formed on the intermediate transfer medium. The color toner image is secondarily transferred onto a transfer sheet. In an image forming apparatus that does not include an intermediate transfer medium, only the photoconductor has a function as an image carrier. In an image forming apparatus that includes an intermediate transfer medium, an intermediate transfer medium is also used as an image carrier. It has a function.

  In these image forming apparatuses, the transfer efficiency from the image carrier to the transfer target (for example, the primary transfer efficiency from the photoconductor to the intermediate transfer medium or the secondary transfer efficiency from the intermediate transfer medium to the transfer paper) is 100%. Therefore, the toner remains on the image carrier after the transfer is completed. Therefore, the image forming apparatus described in Patent Document 1 includes a cleaning unit that removes residual toner on the image carrier and a waste toner container that stores residual toner removed by the cleaning unit as waste toner. Further, in order to prevent the waste toner from overflowing from the waste toner container, an optical for detecting that the waste toner storage capacity stored in the waste toner container is close to the maximum storage capacity of the container, that is, a so-called near-end state. Near-end detectors such as sensors and limit switches are provided. That is, the amount of waste toner is constantly monitored by the near-end detector, and when a near-end state is detected, a message prompting the user to replace the waste toner container is displayed.

Japanese Patent Laying-Open No. 2003-271023 (FIG. 6)

  Thus, the near-end detector is arranged and adjusted so that the waste toner capacity at the time of near-end detection is smaller than the maximum capacity of the container. Therefore, it is not necessary to prohibit printing immediately after near-end detection, and printing is continued until the maximum capacity is reached. This is because the user does not always prepare a replacement waste toner container. By displaying such a near-end display, a new waste toner container is printed before printing is prohibited due to a full waste toner. Can be prepared. Therefore, some users may wish to set a longer period from the entry of the near-end state to the prohibition of printing due to reasons such as securing a sufficient preparation period.

  Here, when the cause of the waste toner was analyzed, the following was found. That is, the main factor for generating waste developer such as waste toner is not only the residual developer after the transfer described above, but also the patch image is one of the generation factors. This patch image is an image for condition control processing that adjusts the operating condition (image forming condition) of each part of the apparatus when executing the image forming operation to the optimum condition. That is, when a predetermined execution requirement (for example, a predetermined number of continuous prints immediately after the apparatus is turned on) is satisfied, a charging bias and a developing bias as density control factors that affect image quality are changed for each color. A plurality of patch images are formed on the image carrier. The charging bias and the developing bias are set to optimum values based on the density detection result of the patch image. On the other hand, the patch image after density detection is entirely removed by the cleaning means. Then, all the developer constituting the patch image is collected as a waste developer in a waste developer container. Thus, a large amount of waste developer such as waste toner is generated each time the condition control process is executed. For this reason, frequent condition control processing in the near-end state has been one of the factors that hinder the user's desire to print for as long as possible after entering the near-end state.

  The present invention has been made in view of the above problems, and performs an image forming operation for forming an image on an image carrier using a developer, and removes the developer remaining on the image carrier to eliminate waste. In an image forming apparatus to be collected as a developer and a control method of the apparatus, a technique that can extend a period from a near-end detection until a waste developer container is full according to a user's request. The purpose is to provide.

  The present invention is an image forming apparatus that executes an image forming operation for forming an image on an image carrier using a developer, removes the developer remaining on the image carrier, and collects it as a waste developer. In order to achieve the above object, the waste developer container for storing the waste developer and the amount of the waste developer stored in the waste developer container are close to the maximum capacity of the waste developer container. Near-end detection means for detecting the near-end, and control means for executing a condition control process for adjusting the image forming condition to the optimum condition when executing the image forming operation based on the density detection result of the patch image formed by the image forming operation And the control means is characterized by allowing the number of executions of the condition control process after the near-end detection to be reduced.

  In addition, the present invention executes an image forming operation for forming an image on an image carrier using a developer, and removes the developer remaining on the image carrier and collects it as a waste developer. In order to achieve the above object, the apparatus control method is a condition control that adjusts an image forming condition when performing an image forming operation to an optimum condition based on a density detection result of a patch image formed by the image forming operation. When the process is executed and when it is detected that the amount of the waste developer accommodated in the waste developer container approaches the maximum capacity of the waste developer container, the number of executions of the condition control process after the detection is reduced. And a process for allowing this.

  In the invention thus configured (image forming apparatus and method for controlling the apparatus), a condition control process is executed, and a patch image is formed on the image carrier for the condition control process. The developer constituting the patch image is collected in a waste developer container as a waste developer after the condition control process. Therefore, as the condition control process is executed, the amount of waste developer in the container increases and eventually becomes full. Therefore, before the waste developer container is filled with the waste developer (maximum capacity), the amount of waste developer stored in the waste developer container approaches the maximum capacity of the waste developer container. Near end is detected. Further, the present invention allows a reduction in the number of executions of the condition control process after the near end is detected. For this reason, it is possible to reduce the number of executions of the condition control process after near-end detection as necessary, and the increase in the amount of waste developer in the waste developer container is also reduced by the reduction in the number of times. As a result, it is possible to extend the period from the near-end detection until the waste developer container is full.

  Here, the following can be adopted as a specific mode for reducing the number of executions of the condition control process after the near-end detection. That is, the control unit may receive a command related to the number of executions of the condition control process, and may include a regulating unit that regulates part or all of the condition control process after the near-end detection according to the command. As a result, the number of executions of the condition control process after the near-end detection can be reliably reduced.

  Further, notification means for notifying that the waste developer container is approaching full in response to near end detection is further provided, and the control means is configured to accept information input by the user in response to the notification as a command. May be. By providing the notification means in this way, it is possible to prompt the user to replace the waste developer container at an appropriate timing. In addition, at this timing, the user can specify the control of the condition control process after the near-end detection. For example, the user can also specify that no condition control processing is performed after the near-end detection. This corresponds to the above-mentioned “restrict all of the condition control processing”. In addition, the user may specify that the condition control process is thinned out after the near-end detection, and this corresponds to the above-mentioned “restrict part of the condition control process”.

  Moreover, the following can be mentioned as another aspect of "restricting part of the condition control processing" described above. That is, the control means sets a plurality of device operation statuses in advance as execution requirements for executing the condition control process, while receiving a command, removes some or all of the device operation statuses from the execution requirements and performs condition control. You may comprise so that the frequency | count of execution of a process may be reduced. As an execution requirement of the condition control process, for example, setting of an apparatus operation status such as power-on of the apparatus, return from sleep, and reaching a predetermined number of prints has been conventionally performed. Therefore, after the near-end detection, only a part of the plurality of execution requirements may be an execution requirement, and a part of the condition control process may be prohibited and the number of executions of the condition control process after the near-end detection may be executed. . Note that the waste developer container is replaced after the near end is detected. At this time, it is possible to return to normal printing by returning the operation status of the apparatus that is out of the execution requirement to the execution requirement.

<Device configuration>
FIG. 1 is a diagram showing an embodiment of an image forming apparatus to which the present invention is applied. 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, when an image signal is given to the main controller 11 from an external device such as a host computer, the CPU 101 provided in the engine controller 10 controls each part of the engine unit EG in response to a command from the main controller 11. Then, a predetermined image forming operation is executed, 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 roller 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 roller 23 is applied with a predetermined charging bias, and charges the outer peripheral surface of the photosensitive member 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 roller 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 roller 23. The exposure unit 6 exposes the light beam L onto the photosensitive member 22 in accordance with an image signal given from an external device, and forms 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 configured as a support frame 40 that is rotatably provided about a rotation axis center 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 are provided. The developing unit 4 is rotationally driven by a developing unit drive motor 47 that is a stepping motor controlled by the engine controller 10. Further, the apparatus main body is provided with a rotary lock 45 that comes into contact with and separates from the developing unit 4. If necessary, the rotary lock 45 abuts on the outer peripheral portion of the support frame 40 of the developing unit 4 to act as a brake and lock mechanism that restrains the rotation of the developing unit 4 and stops and positions the developing unit 4 at a predetermined position. .

  Then, based on a control command from the engine controller 10, when the developing unit 4 is driven to rotate, the developing devices 4Y, 4C, 4M, and 4K are selectively positioned at predetermined positions facing the photoconductor 22. A developing roller 44 that is provided in the developing unit and carries toner of a selected color is disposed to face the photosensitive member 22 with a predetermined gap therebetween, and the surface of the photosensitive member 22 from the developing roller 44 at the opposed position. Toner is applied. As a result, the electrostatic latent image on the photosensitive member 22 is visualized with the selected toner color.

  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, the color toner images formed on the photosensitive member 22 are superimposed on the intermediate transfer belt 71 to form a color image, and the color image is taken out from the cassette 8 and conveyed. The color image is secondarily transferred onto the sheet S conveyed to the secondary transfer region TR2 along the FF.

  The secondary transfer region TR2 is a nip portion where the surface of the intermediate transfer belt 71 stretched over the roller 73 and the secondary transfer roller 86 that contacts and separates from the belt surface. The sheets S stacked and stored in the cassette 8 are taken out one by one by the rotation of the pickup roller 88 and placed on the transport path FF. Then, the feed rollers 84 and 85 and the gate roller 81 are rotated and conveyed to the secondary transfer region TR2 along the conveyance path FF.

  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, it is as follows. A gate roller 81 is provided on the front side of the secondary transfer region TR2 on the transport path FF, and a pre-gate sheet detection sensor 801 is further provided on the front side thereof. When the pre-gate sheet detection sensor 801 detects that the sheet S conveyed on the conveyance path FF has arrived, the conveyance of the sheet S is temporarily stopped and synchronized with the timing of the circumferential movement of the intermediate transfer belt 71. By restarting the rotation of the gate roller 81, the sheet S is fed into the secondary transfer region TR2 at a predetermined timing. In this way, the toner image formed on the intermediate transfer belt 71 is secondarily transferred onto the surface of the sheet S passing through the secondary transfer region TR2.

  The sheet S on which the color image is thus formed is fixed with the toner image by the fixing unit 9 and is conveyed to the discharge tray portion 89 provided on the upper surface portion of the apparatus main body via 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, it is placed again on the transport path FF before the gate roller 81. At this time, the image is transferred first on the surface of the sheet S that contacts the intermediate transfer belt 71 and transfers the image in the secondary transfer region TR2. It is the opposite surface. In this way, images can be formed on both sides of the sheet S.

  In addition to the pre-gate sheet detection sensor 801, sheet detection sensors 802 to 804 for detecting whether or not a sheet has passed on the path are provided at each position on the sheet conveyance path FF and the reverse conveyance path FR. Based on the outputs of these sensors, the sheet conveyance timing is managed and jam detection is performed at each position.

  A cleaner 76 is disposed in the vicinity of the roller 75. The cleaner 76 includes a cleaner blade 761 that can be moved toward and away from the roller 75 by an electromagnetic clutch (not shown), and a waste toner tank 762. Then, the cleaner blade 761 abuts on the surface of the intermediate transfer belt 71 stretched over the roller 75 in a state of moving to the roller 75 side, and the toner remaining on the outer peripheral surface of the intermediate transfer belt 71 after the secondary transfer is removed. Remove by scraping. The toner scraped off is stored in a waste toner tank 762 as waste toner. The waste toner tank 762 is provided with a waste toner sensor 763 for detecting the fullness (maximum capacity) of the tank. Further, in the present embodiment, a near-end detection sensor 764 is disposed below the waste toner sensor 763. Therefore, when the top of the waste toner in the tank 762 reaches the sensing height position P1 of the near-end detection sensor 764 as the waste toner is collected, it indicates that the waste toner amount has approached the maximum accommodation amount. That is, a near end is detected.

  The cleaner blade 761 is controlled to be separated and abutted so as to remove the toner remaining on the intermediate transfer belt 71 in the same rotation when the image is transferred to the sheet S in the secondary transfer region TR2. The Therefore, for example, when the apparatus continuously forms monochrome images, the image transferred to the intermediate transfer belt 71 in the primary transfer region TR1 is immediately transferred to the sheet S in the secondary transfer region TR2, and thus the cleaner blade 761. Is held in contact. On the other hand, when forming a color image, it is necessary to keep the cleaner blade 761 away from the intermediate transfer belt 71 while the toner images of the respective colors are superimposed on each other. Then, the toner images of the respective colors are superimposed on each other to complete a full-color image, and the cleaner blade 761 is brought into contact with the intermediate transfer belt 71 in order to remove residual toner in the same rotation as the secondary transfer onto the sheet S. The Rukoto.

  Further, a density sensor 60 and a vertical synchronization sensor 77 are arranged 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 adjusts the operating conditions of each part of the apparatus affecting the image quality, for example, the developing bias applied to each developing device and the intensity of the light beam L (condition control processing; patch processing). It is carried out. The density sensor 60 is configured to output a signal corresponding to the image density of a region of a predetermined area on the intermediate transfer belt 71 using, for example, a reflection type 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 vertical synchronization sensor 77 is a sensor for detecting the reference position of the intermediate transfer belt 71 and is used to obtain a synchronization signal output in association with the rotational drive of the intermediate transfer belt 71, that is, a vertical synchronization signal Vsync. Functions as a sensor. In this apparatus, the operation of each part of the apparatus is controlled based on the vertical synchronization signal Vsync in order to align the operation timing of each part and accurately superimpose the toner images formed in the respective colors.

  Further, memory tags 49Y, 49C, 49M, and 49K are respectively attached to the outer peripheral surfaces of the developing devices 4Y, 4C, 4M, and 4K that correspond to the side surfaces of the developing unit 4 that has a substantially cylindrical shape as a whole. For example, a memory tag 49Y attached to the yellow developing device 4Y is electrically connected to the memory 491Y for storing data relating to the manufacturing lot and usage history of the developing device, the remaining amount of built-in toner, and the like. Loop antenna 492Y. In addition, memory chips 491C, 491M, and 491K and loop antennas 492C, 492M, and 492K are also provided in the memory tags 49C, 49M, and 49K provided in the other developing devices, respectively.

  On the other hand, a wireless communication antenna 109 is also provided on the apparatus main body side. The wireless communication antenna 109 is driven by a transceiver 105 connected to the CPU 101, and by performing wireless communication with the wireless communication antenna on the developing device side, the CPU 101 and a memory provided in the developing device Various data such as consumables management related to the developing device are managed by transmitting and receiving data between them.

  Further, as shown in FIG. 2, the apparatus includes an operation display unit 12 that is controlled by the CPU 111 of the main controller 11. The operation display unit 12 is constituted by, for example, a liquid crystal display, and according to a control command from the CPU 111, operation guidance to the user, progress of the image forming operation, occurrence of an abnormality in the apparatus, replacement timing of any unit, and the like. A predetermined message for notifying is displayed. A plurality of keys (not shown) are provided to give various commands to the apparatus from the user.

  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.

<Correlation between device operation and waste toner amount>
In the image forming apparatus configured as described above, for example, as illustrated in FIG. 3, the amount of waste toner stored in the waste toner tank 762 gradually increases with the printing process. Further, as already described in the section “Problems to be Solved by the Invention”, the image forming apparatus executes patch processing corresponding to “condition control processing” of the present invention in order to improve image quality. Then, the patch image formed on the intermediate transfer belt 71 in the patch processing is completely removed from the intermediate transfer belt 71 by the cleaner blade 761 after the image density is detected, and all the toner constituting the patch image is used as a waste toner tank 762 as waste toner. To be recovered. Here, comparing the amount of waste toner generated in the patch process with the amount of waste toner generated in the printing process, the amount of waste toner generated in one process is overwhelmingly larger. In other words, if the patch process is performed once, the amount of waste toner stored in the tank 762 is greatly increased, and the tank 762 is almost full. Therefore, in the present embodiment, it is possible to execute a mode (hereinafter referred to as “patch process reduction mode”) that reduces the number of executions of the condition control process after the near-end detection. At an appropriate timing, mode switching can be executed between (1) the patch processing normal mode (the patch processing is always performed when the execution requirement is satisfied) and (2) the patch processing reduction mode.

<Mode setting process>
FIG. 4 is a flowchart showing a mode setting process executed by the image forming apparatus shown in FIG. In this embodiment, when the near-end detection sensor 764 detects a near-end and gives a signal to that effect to the CPU 101 of the engine controller 10, the engine controller 10 and the main controller 11 control each part of the apparatus as follows to reduce patch processing. Set the mode transition.

  When the waste toner tank 762 is not in the near-end state, that is, while the near-end signal is not output from the near-end detection sensor 764, the patch processing normal mode is set, and when the patch processing execution requirement is satisfied, Patch processing is always executed. The amount of waste toner in the tank 762 increases as image formation such as patch processing and printing processing is performed.

  When near end is detected in step S11, the main controller 11 controls the operation display unit 12 to display a replacement request for the waste toner tank 762 and an inquiry about mode change (step S12). More specifically, a message prompting the replacement of the waste toner tank 762 is displayed on the operation display unit 12, and the patch processing up to the completion of the tank replacement is performed in either the patch processing normal mode or the patch processing reduction mode. A message to select is displayed. This display informs that the waste toner tank 762 is almost full. Thus, in the present embodiment, the operation display unit 12 functions as the “notification unit” of the present invention.

  Then, the user selects the mode setting via the operation display unit 12 based on the display message of the operation display unit 12, and the mode setting is performed according to the selection result. That is, in step S13, when the main controller 11 receives a user instruction to shift from the patch processing normal mode to the patch processing reduction mode, the main controller 11 sets the patch processing reduction mode (step S14). On the other hand, when the user selects the patch processing normal mode as it is, the patch processing normal mode is maintained as it is.

  As described above, in this embodiment, the operation display unit 12 notifies that the waste toner tank 762 is almost full in response to near-end detection. Therefore, it is possible to prompt the user to replace the waste toner tank 762 at an appropriate timing. In addition, at this timing, the user can set the mode for executing patch processing after near-end detection, and by setting the patch processing reduction mode, it is possible to reduce the number of times patch processing is executed after near-end detection. Yes. In this way, the user can reduce the number of times patch processing is executed after near-end detection according to his / her usage, and the increase in the amount of waste toner in the waste toner tank 762 can be reduced by reducing the number of times. Can be reduced. As a result, it is possible to extend the period from the detection of near end until the waste toner tank 762 becomes full.

  In the present embodiment, the mode setting process of FIG. 4 is executed when the near end is detected for the first time with respect to the currently installed waste toner tank 762, but the execution timing of the mode setting process is limited to this. Is not to be done. For example, the mode setting process (steps S12 to S14) may be executed at a user-desired timing when the user presses a key (not shown) of the operation display unit 12. Further, the mode setting process may be executed using a host computer connected to the image forming apparatus. That is, a program for executing the mode setting process may be incorporated in the printer driver, and the user may read the printer driver screen and perform the mode setting process (steps S12 to S14).

  Next, the operation of the image forming apparatus configured to be able to switch between the patch processing normal mode and the patch processing reduction mode by the mode setting processing as described above will be described in detail with reference to FIGS. In this apparatus, the engine controller 10 controls each part of the apparatus according to a program stored in the ROM 106 in advance, and executes the following control operations.

  FIG. 5 is a flowchart showing an embodiment of the control method of the image forming apparatus according to the present invention. In this embodiment, the CPU 101 of the engine controller 10 confirms that the execution requirements of the patch processing (power-on of the apparatus, return from sleep, reaching a predetermined number of prints, etc.) are satisfied (step S21), and the next step S22. Proceed to In step S22, the CPU 101 determines whether or not the patch processing reduction mode is set. When the normal mode is set (“NO” in step S22), the patch process (step S26) is executed as in the conventional apparatus.

  FIG. 6 is a flowchart showing the patch processing operation. This patch processing is processing for obtaining an optimum exposure power after obtaining an optimum developing bias for each toner color of yellow (Y), magenta (M), cyan (C), and black (K). Specifically, one toner is selected (S260), and a patch image of a predetermined pattern is formed with each bias value while changing and setting the development bias to another stage (step S261). Then, the image density of the patch image formed in this way is detected by the density sensor 60 (step S262). When the image density of the toner color patch image is obtained in this way, the correspondence between the developing bias and the image density can be found from these values, so that the image density matches the predetermined target density based on the relationship. The development bias value is calculated. Thereby, the optimum developing bias is obtained (step S263). However, if the optimum value is not within the development bias variable range of the apparatus, the value closest to the optimum value calculated in the variable range is set as the optimum development bias. In this manner, the process of obtaining the optimum developing bias (steps S260 to S263) is repeated until “YES” is determined in step S264, and the optimum current developing bias is obtained for all colors.

  Subsequently, the optimum exposure power for each color, that is, the optimum value of the intensity of the exposure beam L when the electrostatic latent image corresponding to each color is formed on the photosensitive member 22 is calculated (steps S265 to S268). The processing here is the same as the optimum development bias calculation processing (steps S261 to S263) described above except that the control factor is exposure power instead of the development bias, but if necessary, a patch image to be formed is formed. The image patterns may be different. In this case, it is preferable to use the optimum value obtained previously as the setting value of the developing bias. Thus, “YES” is determined in step S269, the optimum developing bias and the optimum exposure power are obtained for each color, and the patch processing is ended.

  Returning to FIG. 5, when the patch process (step S26) is completed, the image forming condition is set to the optimum condition obtained by the patch process (step S27). Thus, the condition establishment process for each color is completed. In the present specification, “condition control processing” refers to processing for adjusting the image forming condition when executing the image forming operation to the optimum condition based on the density detection result of the patch image.

  On the other hand, when it is determined in step S22 that the patch processing reduction mode is set, patch processing is executed at a rate of once every predetermined number of times n0 (steps S24 to S28). That is, in the present embodiment, the count n is stored in the RAM 107 in a non-volatile manner so that patch processing is performed after the near-end detection, and zero is stored as an initial value when the waste toner tank 762 is attached. In step S23, the count n is read from the RAM 107.

  In the next step S24, it is determined whether or not the count n coincides with a predetermined value n0 (≧ 1). If they do not match, the patch processing is skipped while incrementing the count n by 1. On the other hand, if they match, the count n is cleared and returned to zero, and then the patch processing (step S26) and optimum condition setting ( Step S27) is performed. That is, in this embodiment, when the patch processing reduction mode is set, even if the patch processing execution requirement is satisfied, the patch processing is executed only once per predetermined value n0.

  As described above, in this embodiment, when the patch processing reduction mode is set, the number of times patch processing is executed can be suppressed, and the increase rate of the waste toner amount in the waste toner tank 762 can be reduced. it can. As a result, it is possible to extend the period from the detection of near end until the waste toner tank 762 becomes full. As described above, in this embodiment, the CPU 101 of the engine controller 10 accepts the patch processing reduction mode, and when the mode is set, part of the patch processing after near-end detection is regulated. Part ". Further, the patch processing reduction mode setting substantially corresponds to “command related to the number of times of execution of the condition control processing”.

  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 embodiment of FIG. 5, the number of times of patch processing is thinned out, which corresponds to “regulating part of the condition control processing” of the present invention. Here, you may comprise so that a part of patch processing may be controlled according to the kind of execution requirement.

  FIG. 7 is a flowchart showing another embodiment of the image forming apparatus according to the present invention. In this embodiment, three apparatus operating conditions are set as execution requirements for patch processing: (a) power-on of the apparatus, (b) return from sleep, and (c) a predetermined number of prints. In step S31, it is determined whether the CPU 101 of the engine controller 10 is set to the patch processing reduction mode. When the normal mode is set (“NO” in step S31), the patch process (step S35) is performed in any of the above three apparatus operating situations (steps S32 to S34) as in the conventional apparatus. And optimal condition setting (step S36) is performed.

  On the other hand, when the reduction mode is set (“YES” in step S31), (a) patch processing (step S35) and optimum condition setting (step S36) are executed only immediately after the apparatus is turned on. The That is, in the patch processing reduction mode, the apparatus operating statuses (b) and (c) are excluded from the execution requirements for patch processing. Thus, the number of executions of the patch process is reduced, which corresponds to “restrict part of the condition control process” of the present invention. When the patch processing normal mode is restored, the apparatus operating statuses (b) and (c) are returned to the patch processing execution requirements.

  Further, in the above embodiment, a part of the condition control process is regulated by thinning out the number of times of patch processing or by narrowing down the execution requirements. This corresponds to “restrict part of the condition control processing” in the present invention. However, when patch processing is not performed at all, there is a possibility that image quality, particularly color image degradation, may occur, so it is desirable to adopt the embodiment shown in FIGS. 5 and 7 for color images.

  In the above embodiment, the case where the patch process is shifted from the normal mode to the reduction mode has been mainly described. However, when the waste toner tank 762 is replaced, the mode setting process is not executed, and the normal mode is automatically set. You may comprise so that it may be set. Further, it may be configured to automatically clear the count n corresponding to the automatic setting, or to automatically perform the process of returning the apparatus operation statuses (b) and (c) to the execution requirements of the patch process.

  Further, in the above-described embodiment, the present invention is applied to an apparatus that forms an image using toners of four colors of yellow, magenta, cyan, and black. However, the type and number of developers are limited to the above. It is not a thing but arbitrary. In addition to the rotary development type apparatus as in the present invention, the so-called tandem type image forming apparatus in which developing units corresponding to the respective toner colors are arranged in a line along the sheet conveying direction. The present invention is also applicable. Furthermore, the present invention is not limited to the electrophotographic apparatus as in the above embodiment, but can be applied to all image forming apparatuses.

1 is a diagram showing an embodiment of an image forming apparatus to which the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus in FIG. 1. FIG. 6 is a diagram illustrating a correlation between apparatus operation and waste toner amount. 3 is a flowchart showing mode setting processing executed by the image forming apparatus in FIG. 1. 3 is a flowchart illustrating an embodiment of a method for controlling the image forming apparatus according to the present invention. The flowchart which shows a patch process. 9 is a flowchart showing another embodiment of the image forming apparatus according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine controller (control means) 11 ... Main controller (control means) 12 ... Operation display part (notification means) 71 ... Intermediate transfer belt (image carrier), 101 ... CPU (control means, regulation part), 762 ... Waste toner tank (waste developer container), 764 ... Near-end detection sensor

Claims (6)

In an image forming apparatus that executes an image forming operation for forming an image on an image carrier using a developer, removes the developer remaining on the image carrier, and collects it as a waste developer.
A waste developer container containing the waste developer;
Near-end detection means for detecting a near-end indicating that the amount of the waste developer accommodated in the waste developer container has approached the maximum capacity of the waste developer container;
Control means for executing a condition control process for adjusting an image forming condition to an optimum condition when executing the image forming operation based on a density detection result of the patch image formed by the image forming operation
The image forming apparatus according to claim 1, wherein the control unit allows a reduction in the number of executions of the condition control process after the near-end detection.   2. The control unit according to claim 1, further comprising a restriction unit that receives a command related to the number of execution times of the condition control process and regulates part or all of the condition control process after the near-end detection according to the command. Image forming apparatus. A notification means for notifying that the waste developer container is approaching full in response to the near-end detection;
The image forming apparatus according to claim 2, wherein the control unit receives information input by a user in response to the notification as the command.   The control means sets in advance a plurality of apparatus operating conditions as execution requirements for executing the condition control process, and when receiving the command, part or all of the apparatus operating conditions are excluded from the execution requirements. The image forming apparatus according to claim 2, wherein the number of executions of the condition control process is reduced.   5. The image forming apparatus according to claim 4, wherein when the waste developer container is replaced after the near-end is detected, the control unit returns the operation status of the apparatus deviating from the execution requirement to the execution requirement. In a control method of an image forming apparatus that executes an image forming operation for forming an image on an image carrier using a developer, removes the developer remaining on the image carrier, and collects it as a waste developer.
Executing a condition control process for adjusting an image forming condition when executing the image forming operation to an optimum condition based on a density detection result of the patch image formed by the image forming operation;
When it is detected that the amount of the waste developer accommodated in the waste developer container has approached the maximum capacity of the waste developer container, it is allowed to reduce the number of executions of the condition control processing after the detection. And a method for controlling the image forming apparatus.

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