JP2011197221A - Image forming apparatus, control method of image forming apparatus, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which prevents image deterioration and efficiently uses a developer by reducing damage to a transfer belt caused by a residual toner on a transfer belt, and to provide a control method of the image forming apparatus, and a program.SOLUTION: The image forming apparatus includes: an image holding means for forming an electrostatic latent image on its surface; a developing means for forming a toner image by developing an electrostatic latent image with a developer containing a toner and an external additive adhering to the periphery of the toner; a transfer means to which a toner image is transferred; a toner image reading means for reading the toner image formed on the transfer means; and a control means for controlling the formation of a toner image pattern on the transfer means. The control means determines a use level based on a use condition of at least the developing means or the transfer means. Based on the determined use level, the control means controls the toner image pattern formed on the transfer means opposite to a portion through which the toner image reading means passes, and the timing of the formation of the toner image pattern.

Description

  The present invention relates to an image forming apparatus such as a color copying machine, a facsimile machine, a color printer or a color multifunction machine, and a control method and program for the image forming apparatus, and in particular, superimposes different color toner images on a transfer belt of an intermediate transfer member. The present invention relates to an image forming apparatus configured to obtain a color image by transferring the image, a control method for the image forming apparatus, and a program.

  In recent years, various image forming apparatuses such as a color copying machine, a facsimile machine, a color printer, and a multi-function machine have been widely used. An image forming operation by such an image forming apparatus will be described below.

  First, an electrostatic latent image is formed by exposing the photosensitive member, which is an image carrier that rotates in the sub-scanning direction according to a document image or image data, by exposure means. At this time, the photosensitive member is uniformly charged in advance by a charger. Next, toner is attached to the electrostatic latent image on the photosensitive member by a developing unit to form a toner image, and the toner image is transferred onto a sheet as a recording medium by a transferred unit. Then, the toner image on the paper is fixed by being heated and pressed by a fixing unit including a heating roller and a pressure roller with a built-in heater. In order to construct a color image, the toner image formed on the photosensitive member is superimposed on the transfer belt of the intermediate transfer member and transferred by the developing means.

  In the developing device mounted on the image forming apparatus as described above, a toner containing a toner and an external additive attached to the outer periphery of the toner is used to be carried on a latent image carrier such as a photoreceptor. A system for developing a latent image is known.

  A developer carried on a developer carrier such as a developing roller is transported to a development area which is an area opposite to the latent image carrier, and the toner in the developer is transferred to a latent image on the latent image carrier. Then, the latent image is developed, and a color image is formed on the transfer belt. Although the toner image formed on the transfer belt is transferred to the paper, toner, external additives, and paper dust on the paper that are not transferred to the paper may remain on the transfer belt. As shown in FIG. 8, toner, external additives, and the like remaining on the transfer belt are collected by a cleaning blade disposed in contact with the transfer belt.

  An external additive having a smaller diameter than the toner adheres to the contact portion between the transfer belt and the cleaning blade. Unnecessary toner and external additive on the transfer belt are collected in a waste toner box by the external additive deposited on the contact portion between the transfer belt and the cleaning blade. Here, the toner having particles larger than the external additive is prevented from slipping between the transfer belt and the cleaning blade. Further, the external additive becomes a polishing effect with the rotating transfer belt, and the fixed matter on the transfer belt can be removed at the contact portion with the cleaning blade.

  The external additive adhering to the outer periphery of the toner is supplied onto the transfer belt as a developer together with the toner in the developing device. As the developing device drive time elapses, the developer is agitated in the developing device by repeating a warm-up operation and a printing operation that accompany power off / on and return from the sleep mode, which is an energy saving mode. For this reason, as the driving distance of the developing device becomes longer, the number of times of stirring increases, so that the external additive externally added to the toner particle surface is detached. That is, as shown in FIG. 9, the amount of attached external additive is smaller in the final developer having a long driving time of the developing device than in the initial developer having a short driving time of the developing device.

  As the amount of the external additive supplied from the developing device to the transfer belt is reduced, the amount of the external additive deposited on the contact portion between the transfer belt and the cleaning blade is reduced. That is, in the developer supplied from the developing device driven for a certain time or more, the polishing effect by the external additive in the transfer belt is reduced, and the toner passing through the cleaning blade increases, and the wax contained in the toner There has been a problem that components and the like adhere to the transfer belt. As shown in FIG. 10, it is known that the number of fixing points of the toner component on the transfer belt increases when the driving distance of the developing device exceeds a certain distance.

  The fixing of the toner component as described above is fine that does not appear in the printing result, but increases as the traveling distance of the transfer belt increases. If the toner component is fixed on the transfer belt and the toner component is fixed on the transfer belt facing the toner image reading sensor passing portion on the transfer belt, the color matching control pattern reference position is erroneously detected. . As a result, there is a problem that the color matching control cannot be adjusted correctly and the sub-scanning position of the printing result is shifted. In addition, a toner image is not formed at the toner component fixing portion, and the detection result read by the sensor with the density adjustment pattern is erroneously detected, so that there is a problem that density stability cannot be guaranteed. Furthermore, since the toner image is not formed when the toner component fixing portion becomes large, there is a problem that an image omission occurs in the printing result.

  In order to solve the above-described problem, for example, a technique for forming a toner image pattern on a transfer belt facing a toner image reading sensor passing portion according to a use state of a developing device has been proposed (for example, Patent Document 1). . In Patent Document 1, toner adhesion is reduced by forming a toner image pattern on a transfer belt facing the toner image reading sensor passage portion based on the usage state of the developing device, and the color matching control pattern reference position and This prevents misalignment adjustment of the color matching control, which is a misalignment in the sub-scanning position of the printing result.

  Further, as another technique for solving the above-mentioned problem, the image carrier is moved so that the residual toner on the transfer belt can be sufficiently collected at the contact portion between the cleaning blade and the transfer belt. A technique for enhancing the cleaning mechanism by changing the relative position has been proposed (for example, Patent Document 2). Further, as a technique for preventing image deterioration due to residual toner on the transfer belt, a technique for positively discharging toner from a developing device has been proposed (for example, Patent Document 3).

  Here, the opportunity to supply the developer onto the transfer belt is mainly a printing operation, but the developer may be used for the adjustment operation of each actuator in a warm-up operation or the like. However, in general, this adjustment operation is controlled not to be executed frequently because the warm-up time and the like become longer. Therefore, a technique has been proposed in which a developer is supplied to the contact portion between the transfer belt and the cleaning blade to suppress the cleaning blade and thereby improve the cleaning effect (for example, Patent Document 4).

  However, in the technique of Patent Document 1 described above, toner adhesion on the transfer belt facing the toner image reading sensor passing portion can be reduced, but the transfer belt has a longer rotation distance when the toner image pattern is formed, so that the life of the transfer belt is increased. There was a problem that became short-lived.

  Moreover, although the technique of the said patent document 2 can improve the cleaning effect, there existed a subject that cost will become high because the number of parts increases.

  Furthermore, in the technique of the above-mentioned Patent Document 3, all the toner that may remain on the transfer belt is forcibly discarded when a normal image forming operation is performed. There was a problem that it was not possible.

  In the technique described in Patent Document 4, since the developer is supplied to the entire surface of the transfer belt, the amount of toner consumption increases, and there is a problem that the toner cannot be used efficiently.

  The present invention has been made in view of such circumstances, solves the above-described problems, reduces damage to the transfer belt due to residual toner on the transfer belt, prevents image deterioration, and efficiently applies the developer. An object of the present invention is to provide an image forming apparatus to be used, an image forming apparatus control method, and a program.

  The image forming apparatus of the present invention comprises at least one or more image bearing means for forming an electrostatic latent image on the surface, and a developer containing toner on the electrostatic latent image and an external additive attached to the outer periphery of the toner. At least one developing means for developing a toner image, a transfer means to which the toner image is transferred, a toner image reading means for reading the toner image formed on the transfer means, and a toner to the transfer means Control means for controlling the formation of the image pattern, and the control means determines the use level based on the use state of at least one of the developing means and the transferred means, and based on the determined use level, the toner A toner image pattern formed on a transfer-receiving unit facing the image reading unit passing portion and a formation timing of the toner image pattern are controlled.

  According to the control method of the image forming apparatus of the present invention, at least one image carrying step for forming an electrostatic latent image on the surface and at least one developing unit are attached to the electrostatic latent image on the toner and the outer periphery of the toner. At least one of a developing step for developing the developer containing the external additive and forming a toner image, a transfer step for transferring the toner image to the transfer means, and a development means and a transfer means A toner image formed on a transfer-receiving means that faces a passage portion of a toner image reading unit that determines a use level based on a use state and reads a toner image formed on the transfer-receiving unit based on the determined use level And a control step for controlling the formation timing of the pattern and the toner image pattern.

  The program of the present invention is a developer in which an electrostatic latent image is formed on a surface, and at least one or more developing means includes toner on the electrostatic latent image and an external additive attached to the outer periphery of the toner. The usage level is determined based on the processing state of developing the toner image to form a toner image, the processing of transferring the toner image to the transfer means, and the use state of at least one of the development means and the transfer means. A process for controlling the toner image pattern formed on the transfer-receiving means facing the passing portion of the toner image reading means for reading the toner image formed on the transfer-receiving means based on the level, and the formation timing of the toner image pattern; Is executed by a computer.

  According to the present invention, it is possible to prevent image deterioration while efficiently using a developer.

1 is a diagram illustrating an overall schematic configuration example of a mechanism unit of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram illustrating a schematic functional configuration example of a control mechanism of the image forming apparatus according to the present embodiment. 5 is a flowchart illustrating a schematic example of a flow of warm-up processing that is pre-printing processing of the image forming apparatus according to the present exemplary embodiment. 6 is a flowchart illustrating an example of a flow of processing for supplying a developer to a transfer belt of the image forming apparatus according to the exemplary embodiment. 6 is a flowchart illustrating an example of a flow of a developing device selection process that is a target of toner image pattern formation in the image forming apparatus according to the present exemplary embodiment. 6 is a flowchart illustrating an example of a flow of toner image length selection / pattern latent image timing selection processing in the image forming apparatus according to the present exemplary embodiment. FIG. 4 is a diagram illustrating an example of a toner image pattern of the image forming apparatus according to the present embodiment. It is a figure which shows the example of the cleaning blade arrange | positioned in contact with a transfer belt. It is a figure which shows the example of a relationship between the drive time of a developing device, and the attachment amount of an external additive. FIG. 6 is a diagram illustrating an example of a relationship between a driving distance of a developing device and an increase in a fixing portion of a toner component on a transfer belt.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings. Bk, M, C, and Y shown in the following embodiments and drawings indicate black, magenta, cyan, and yellow, respectively.

(Configuration of image forming apparatus)
FIG. 1 shows an example of the overall configuration of a mechanism unit of an image forming apparatus according to the present embodiment. The image forming apparatus according to the present embodiment includes a paper feed tray 1, a paper feed roller 2, a registration roller 3, a registration sensor 4, a transfer belt 5, development devices 6Bk, 6M, 6C, and 6Y, a secondary transfer driving roller 7, and a transfer. Belt tension roller 8, photoreceptors 9Bk, 9M, 9C, 9Y, chargers 10Bk, 10M, 10C, 10Y, exposure unit 11, developing units 12Bk, 12M, 12C, 12Y, cleaner blades 13Bk, 13M, 13C, 13Y, laser Light 14Bk, 14M, 14C, 14Y Primary transfer rollers 15Bk, 15M, 15C, 15Y, Secondary transfer roller 16, Belt cleaner 17, Paper discharge roller 18, Fixing device 20, Cleaning blade 21, Paddles 40Bk, 40M, 40C 40Y, TM (toner image reading) sensor 41, waste toner full detection sensor 43, waste toner And a over box 44 or the like. Note that the image forming apparatus according to the present embodiment does not necessarily have all the above-described configurations.

  In this embodiment, as the image forming apparatus, developing devices 6Bk, 6M, 6C, and 6Y that are image forming units (for example, electrophotographic process units of multiple colors) are arranged along a transfer belt 5 corresponding to a transfer target. An example of what is called a tandem type in which the toner image formed on the photoconductor in the developing device is pressed against the transfer belt at once will be described. However, the configuration of the image forming apparatus is not limited to this.

  The transfer belt 5 rotates in the direction indicated by the arrow in FIG. 1 (counterclockwise), and a plurality of developing devices 6Bk, 6M, 6C, and 6Y are arranged in order from the upstream side in the rotation direction. The plurality of developing devices 6Bk, 6M, 6C, and 6Y have the same internal configuration except that the color of the toner image to be formed is different. The developing device 6Bk forms a black toner image, the developing device 6M forms a magenta toner image, the developing device 6C forms a cyan toner image, and the developing device 6Y forms a yellow toner image. Further, the developing devices 6Bk, 6M, 6C, and 6Y include paddles 40Bk, 40M, 40C, and 40Y that stir the developer containing toner and an external additive, respectively. Here, silica or the like can be applied as the external additive, but is not limited thereto.

  In the following description, the developing device 6Bk will be specifically described as an example, but the other developing devices 6M, 6C, and 6Y are the same as the developing device 6Bk, and therefore each configuration of the developing devices 6M, 6C, and 6Y is described. Regarding the elements, instead of Bk attached to each component of the developing device 6Bk, only the symbols distinguished by M, C, and Y are displayed in the drawing, and the description is omitted.

  The transfer belt 5 is an endless belt wound around a secondary transfer driving roller 7 and a transfer belt tension roller 8 that are rotationally driven. The secondary transfer drive roller 7 is rotationally driven by a drive motor which is a drive source (not shown). The drive motor, the secondary transfer drive roller 7 and the transfer belt tension roller 8 function as drive means for moving the transfer belt 5.

  The developing device 6Bk includes a photoconductor 9Bk, a charger 10Bk, an exposure device 11, a developing device 12Bk, a cleaner blade 13Bk, and the like.

  The charger 10Bk is a charging unit that is arranged around the photoconductor 9Bk and uniformly charges the photoconductor 9Bk. The exposure device 11 is an exposure unit and is configured to irradiate laser beams 14Bk, 14M, 14C, and 14Y that are exposure lights corresponding to image colors formed by the developing devices 6Bk, 6M, 6C, and 6Y. . The developing device 12Bk visualizes the electrostatic latent image with a black toner as a developer. As a result, a black toner image is formed on the photoreceptor 9Bk. The cleaner blade 13Bk cleans the photoreceptor 9Bk.

  At the time of image formation, the outer peripheral surface of the photoconductor 9Bk is uniformly charged by the charger 10Bk in the dark and then exposed by the laser beam 14Bk corresponding to the black image from the exposure device 11, thereby forming an electrostatic latent image. Is done. The developing device 12Bk visualizes the electrostatic latent image with black toner, and a black toner image is formed on the photoreceptor 9Bk.

  The toner image is transferred onto the transfer belt 5 by the action of the primary transfer roller 15Bk at a position (primary transfer position) where the photoconductor 9Bk and the transfer belt 5 are in contact with each other. By this transfer, an image of black toner is formed on the transfer belt 5. After the transfer of the toner image is completed, the photoreceptor 9Bk waits for the next image formation after unnecessary toner remaining on the outer peripheral surface is removed by the cleaner blade 13Bk.

  As described above, the transfer belt 5 onto which the black toner image is transferred by the developing device 6Bk is conveyed to the next developing device 6M. In the developing device 6M, a magenta toner image is formed on the photoreceptor 9M by a process similar to the image forming process in the developing device 6Bk, and the toner image is superimposed on the black image formed on the transfer belt 5. Transcribed. The transfer belt 5 is further sequentially conveyed to the next developing devices 6C and 6Y, and a cyan toner image formed on the photoconductor 9C and a yellow toner image formed on the photoconductor 9Y by a similar operation. Are superimposed and transferred onto the transfer belt 5.

  As described above, a full-color image is formed on the transfer belt 5, and the transfer belt 5 on which the full-color superimposed image is formed is conveyed to the position of the secondary transfer roller 16. In the case of image formation with only black at the time of image formation, the primary transfer rollers 15M, 15C, and 15Y are retracted to positions separated from the photoreceptors 9M, 9C, and 9Y, respectively, and the above-described image formation process is performed in black. Only if.

  During the sheet transport operation during image formation, the sheets S stored in the sheet feeding tray 1 are sequentially driven by rotating the sheet feeding roller 2 in the direction indicated by the arrow (counterclockwise) in FIG. It is sent out, stops at the position of the registration roller 3 and waits. The stop timing is when a predetermined time has elapsed since the leading edge of the paper S was detected by the registration sensor 4. Here, an example has been described in which the top sheet stored in the sheet feeding tray 1 is sent out, but the present invention is not limited to this.

  The driving of the registration roller 3 is started at a timing such that the position of the toner image and the paper S overlaps on the toner image conveyed by the transfer belt 5 and the secondary transfer roller 16. At this time, the registration roller 3 sends out the paper S by being rotationally driven in the direction indicated by the arrow (counterclockwise) in FIG.

  A toner image on the transfer belt 5 is transferred by the secondary transfer roller 16 to the sheet S sent out by the registration roller 3. Thereafter, the toner image is fixed by heat and pressure by the fixing device 20, and discharged (discharged) to the outside of the image forming apparatus by the discharge roller 18 that is rotationally driven in the direction of the arrow (counterclockwise) in FIG. Is done.

  The fixing device 20 includes a heating roller 201 and a pressure roller 202. The heating roller 201 is, for example, an aluminum core metal material coated with a rubber material, and has a heater built therein. On the other hand, the pressure roller 202 can also be made of, for example, a coating of a rubber material on an aluminum core as in the case of the heating roller 201, and is in contact with the heating roller 201 with a certain pressure. Hereinafter, this contact portion is referred to as a “nip portion”.

  By rotating the heating roller 201 by a driving system (driving means) not shown, the pressure roller 202 in contact with the heating roller 201 is also rotated. The toner image secondarily transferred to the paper S is fixed to the paper S by heat and pressure when passing between the two rollers.

  After the transfer of the toner image onto the paper S is completed, the transfer belt 5 is collected by the cleaning blade 21 disposed on the transfer belt 5 in contact with unnecessary toner remaining on the outer peripheral surface and removed by the belt cleaner 17. After that, it waits for the next image formation.

  In this way, an electrostatic latent image of the image is formed on the photosensitive member of the image carrier that is rotationally driven by a drive motor, which is a drive means (not shown), and toner is attached to the formed electrostatic latent image. Thus, a toner image is formed, the formed toner image is transferred to a sheet, the transferred toner image is fixed on the sheet, and the image is printed on the sheet. The removed toner is stored in a waste toner box 44. The waste toner full detection sensor 43 is a detection unit that detects that the amount of waste toner in the waste toner box 44 is full.

  FIG. 2 shows a schematic functional configuration example of the control mechanism of the image forming apparatus according to the present embodiment. As shown in the figure, the image forming apparatus according to the present embodiment includes a control mechanism unit 101 including a control unit 101 corresponding to a CPU and a nonvolatile memory 106 corresponding to a nonvolatile storage unit.

  The control unit 101 is an arithmetic control device that controls functions including operations of the image forming apparatus according to the present embodiment. The control unit 101 includes a ROM 102 and a RAM 103. The ROM 102 is a fixed storage device that stores programs executed by the control unit 101. The RAM 103 is a main storage device used when the control unit 101 executes various control processes, and includes a count value storage unit 104 and a developing device replacement date storage unit 105. The count value storage unit 104 is a part of the storage capacity of the RAM 103, and the control unit 101 adds a drive time count and a drive distance count value of the transfer belt and the developing device, which are added according to the driving state of the photosensitive member drive motor 111. This area stores the total value. The developing device replacement date storage unit 105 is a part of the storage capacity of the RAM 103, and is an area in which the use start date and time when the developing devices 6Bk, 6M, 6C, and 6Y are installed is stored.

  The nonvolatile memory 106 includes a rotation time count storage unit 107, a travel distance count storage unit 108, and a developing device use start date / time storage unit 109, and the total value of the count values stored in the count value storage unit 104. Is stored in the storage unit. The non-volatile memory 106 also stores the date and time when a new product is installed in the developing device use start date and time storage unit 109.

  The photoconductor drive motor 111 is a device that rotationally drives the photoconductors 9Bk, 9M, 9C, and 9Y. When the control unit 101 issues an on / off operation instruction at a timing necessary for the printing operation or warm-up operation by executing the program in the ROM 102, the control unit 101 rotates and stops in response to the operation instruction.

  When the photoconductor drive motor 111 receives an ON operation instruction from the control unit 101, the photoconductor drive motor 111 rotates and drives the photoconductors 9Bk, 9M, 9C, and 9Y and the developing units 12Bk, 12M, 12C, and so on by a mechanical mechanism. The driving force is transmitted to 12Y. On the other hand, when the photosensitive member driving motor 111 receives an OFF operation instruction from the control unit 101, the photosensitive member driving motor 111 stops rotating, and the photosensitive members 9Bk, 9M, 9C, 9Y and the developing devices 12Bk, 12M, 12C, The driving of 12Y is also stopped.

(Warming up process)
FIG. 3 shows a schematic example of the flow of warm-up processing that is pre-printing processing of the image forming apparatus according to the present embodiment. Hereinafter, a schematic example of the flow of the warm-up process will be described with reference to the flowchart shown in FIG.

  First, the image forming apparatus performs initial processing when the power is turned on (step S301). In the initial processing, the mounting check of each consumable such as the developing devices 6Bk, 6M, 6C, and 6Y is performed, and the heater built in the heating roller 201 in the fixing device 20 is turned on. In the initial processing, the polygon motor in the optical unit is started up and the waste toner in the waste toner box 44 is agitated. Next, a developing bias is applied to activate an actuator such as a black developing image forming motor or a color image forming motor (step S302). After the motor is started, a cleaning process for the transfer belt 5 is performed in order to remove waste toner, paper dust, and the like adhering to the transfer belt 5 (step S303). When the cleaning process on the transfer belt 5 is completed, each developer forms a density adjustment pattern on the surface of the transfer belt 5 facing the TM sensor 41, and the TM sensor 41 measures the amount of light to adjust the development bias and the like. To control the density to be stable (step S304).

  Next, an alignment pattern is formed on the transfer belt 5 facing the three TM sensors 41 so that the development positions of Bk, C, M, and Y are aligned on the transfer belt 5. Control is performed so that the positions match (step S305). After the toner image pattern is formed by the color matching process, the driving time and driving distance of the transfer belt 5 and the developing devices 6Bk, 6C, 6M, and 6Y are determined, and the transfer belt 5 that faces the TM sensor 41 is determined on the driving state. A toner image pattern is formed. After completion of the adjustment operation, the transfer roller is cleaned while waiting until the roller surface temperature of the fixing device 20 reaches the target temperature (step S306).

(Developer supply means)
FIG. 4 shows an example of the flow of processing for supplying a developer to the transfer belt 5 of the image forming apparatus according to the present embodiment. Hereinafter, the developer supply unit on the transfer belt 5 in the image forming apparatus according to the present embodiment will be described with reference to the flowchart shown in FIG. The developing device 6Bk will be specifically described below as an example. As described above, since the other developing devices 6M, 6C, and 6Y have the same configuration as the developing device 6Bk, the developing device 6M. , 6C, and 6Y are the same as those of the developing device 6Bk, and the description thereof is omitted here.

  Based on the driving time and driving distance of the transfer belt 5 of the intermediate transfer member and the developing device 6Bk, the usage state of each unit is set to an initial state (level 1), an intermediate state (level 2), and an end state (level 3). It is determined in which state. Level 1 (initial state) determination threshold values are transfer belt rotation time = T1, transfer belt travel distance = M1, development device drive time = S1, development device drive distance = N1, and level 2 (intermediate state) determination threshold values. Transfer belt rotation time = T2, transfer belt travel distance = M2, developing device driving time = S2, developing device driving distance = N2, and when the level is equal to or greater than the level 2 determination threshold, it is determined that the level is 3 (the end state). . In this embodiment, an example in which the level is divided into three levels of level 1, level 2, and level 3 will be described. However, any number of levels can be applied as long as the number is two or more, and the number of levels is increased. Therefore, more delicate control can be performed.

  First, based on the rotation time and the travel distance of the transfer belt 5, it is determined whether the usage level is level 3 (step S401). That is, it is determined whether the rotation time of the transfer belt 5 is T2 or more and the travel distance of the transfer belt 5 is M2 or more. When it is determined that the state of the transfer belt 5 is level 3 (step S401 / YES), the developing device selection process for forming a toner image pattern is performed regardless of the driving time and driving distance of the developing device 6Bk. Transition is made (step S402).

  On the other hand, when the state of the transfer belt 5 is level 1 and level 2 (step S401 / NO), the driving time and driving distance of the developing device 6Bk are determined (step S404). When the rotation time of the developing device 6Bk is less than S1 and the travel distance of the developing device 6Bk is less than N1 (step S404 / NO), it is determined that the state of the developing device 6Bk is level 1. If it is determined that the state of the developing device 6Bk is level 1, the mounting start date and time of the developing device 6B is determined (step S405). Here, when it is determined that the development device mounting start date / time is less than U1 (NO in step S405), since the external additive is deposited on the contact portion of the transfer belt 5 and the cleaning blade 21, the transfer is performed. The toner image pattern is not formed on the belt 5 and the process is terminated.

  In the process of step S404, when it is determined that the rotation time of the developing device 6Bk is S1 or more and the travel distance of the developing device 6Bk is N1 or more (step S404 / YES), the state of the developing device 6Bk is It is determined that the level is 2 or 3, and the process proceeds to step S402. In other words, the developing device to be subjected to pattern formation is selected. Next, a process for selecting a toner image pattern to be formed on the transfer belt 5 is performed (step S403). The toner image is adjusted so that the amount of toner formed on the transfer belt is maximized by adjusting charging and laser light.

  In the above, an example in which the level of the usage state is determined based on at least one of the development device installation start date and time, the development device drive time, the development device drive distance, the transfer belt rotation time, and the transfer belt travel distance. Although described, the present invention is not limited to this. The method of determining the usage state level can be changed as appropriate. For example, the usage state level can be determined based only on the developing device drive time, or can be determined based on other requirements.

(Developer selection process)
FIG. 5 shows an example of the flow of a developing device selection process to be a pattern formation target, which is the process shown in step S402. Hereinafter, an example of the flow of developing device selection processing to be a pattern formation target will be described with reference to the flowchart shown in FIG.

  First, based on the driving time and driving distance of the developing device 6Bk, it is determined whether the developing device 6Bk is within the level 1 threshold (step S501). That is, it is determined whether the driving time of the developing device 6Bk is less than S1 and the driving distance of the developing device 6Bk is less than N1. If it is determined that it is level 1 (step S501 / YES), the developing device state is set to level 1 (step 502).

  Next, when it is determined that the state of the developing device 6Bk is equal to or higher than the threshold value of level 1 (step S501 / NO), the developing device 6Bk is set to level 2 based on the driving time S and the driving distance N of the developing device 6Bk. It is determined whether it is within the threshold value. That is, it is determined whether the driving time of the developing device 6Bk is less than S2 and the driving distance of the developing device 6Bk is less than N2. If it is determined that it is level 2 (step S503 / YES), the developing device state is set to level 2 (step 504). If it is determined in step S503 that the level is equal to or higher than the threshold level 2 (step S503 / NO), the developing device state is set to level 3 (step S505).

  The developing device selection process is repeated for four colors Bk, C, M, and Y. After the target developing device for the toner image to be formed on the transfer belt 5 is determined, the toner image length selection / pattern latent image timing selection process, which is the process of step S403, is performed.

(Toner image length selection / pattern latent image timing selection processing)
FIG. 6 shows an example of the flow of toner image length selection / pattern latent image timing selection processing. Hereinafter, an example of the flow of the toner image length selection / pattern latent image timing selection process shown in step S403 will be described with reference to the flowchart shown in FIG.

  As shown in FIG. 7, the toner image pattern length of the image forming apparatus according to the present embodiment is such that when the state of the developing device is level 1, the main scanning and the sub scanning centering on the toner reading sensor passing portion on the transfer belt 5. The area is set to be narrow in the direction. On the other hand, when the state of the developing device is level 3, the toner image pattern length is set so that the area increases in the main scanning direction and the sub-scanning direction. That is, in this embodiment, as the state level of the developing device increases, the toner image pattern length increases and the area of the toner image pattern in the main scanning and sub-scanning directions also increases. In the present embodiment, the toner image pattern latent image timing formed on the transfer belt 5 becomes shorter as the level of the state of the developing device becomes higher.

  Here, in this embodiment, the toner image formation interval and the toner image pattern length selected when it is determined that the state of the developing device is level 1 are the toner image formation interval 1 and the toner image pattern length 1. Similarly, the toner image formation interval and the toner image pattern length selected when it is determined that the state of the developing device is level 2 are defined as toner image formation interval 2 and toner image pattern length 2. Further, the toner image formation interval and the toner image pattern length selected when it is determined that the state of the developing device is level 3 are set as the toner image formation interval 3 and the toner image pattern length 3. Note that the toner image formation intervals and toner image pattern lengths shown in FIG. 7 are examples, and are not limited to these, and can be changed as appropriate.

  First, the level of any one of the developing devices 6Bk, 6M, 6C, and 6Y is determined based on the driving time S and the driving distance N of the developing devices 6Bk, 6M, 6C, and 6Y by the above-described pattern forming target developing device selection process. It is determined whether or not 1 is set (step S601). When at least one of the developing devices 6Bk, 6M, 6C, and 6Y is set to be level 1 (YES in step S601), the toner image formation interval and the toner image pattern length are set to the toner image formation interval 1. The toner image pattern length is set to 1 (step 602).

  Next, when it is determined that the settings of the states of the developing devices 6Bk, 6M, 6C, and 6Y are not all level 1 (step S601 / NO), the driving time S and driving of the developing devices 6Bk, 6M, 6C, and 6Y are driven. Based on the distance N, it is determined whether any one of the developing devices 6Bk, 6M, 6C, and 6Y is set to be level 2 (step S603). When at least one of the developing devices 6Bk, 6M, 6C, and 6Y is set to be level 2 (YES in step S603), the toner image formation interval and the toner image pattern length are set to the toner image formation interval 2 and The toner image pattern length is set to 2 (step S604).

  On the other hand, if it is determined in step S603 that the settings of the developing devices 6Bk, 6M, 6C, and 6Y are not all level 2 (step S603 / NO), all the developing devices 6Bk, 6M, 6C, and 6Y are set. Is set to level 3, the toner image formation interval and the toner image pattern length are set to the toner image formation interval 3 and the toner image pattern length 3 (step S605).

  In this embodiment, when at least one of the developing devices is set to level 1, an example in which the toner image formation interval and the toner image pattern length are set to the toner image formation interval 1 and the toner image pattern length 1 is described. And explained. This is because if there is one or more developing devices in the level 1 state, it is possible to sufficiently maintain the amount of accumulated external additive at the contact portion between the transfer belt 5 and the cleaning blade 21. However, the present invention is not limited to this, and the setting criteria for the toner image formation interval and the toner image pattern length can be appropriately changed.

  In this embodiment, when forming a toner image pattern on a transfer belt using at least one developer, the developer used is developed more than the developer of level 1 with a short stirring time in the developing device. Control is performed so that the level 3 developer having a longer stirring time in the apparatus has a larger area in the main scanning direction and the sub-scanning direction. As described above, in the level 3 developer in which the supply amount of the external additive to the transfer belt decreases, the area of the toner image pattern to be formed in the main scanning direction and the sub-scanning direction is widened, and the discharge amount of the developer is increased. Also, the amount of external additive supplied onto the transfer belt is increased. On the other hand, when there is at least one level 1 developer having sufficient external additives, the area of the toner image pattern to be formed in the main scanning direction and the sub-scanning direction is narrowed. By executing only when the belt travel distance exceeds a certain distance, wasteful consumption of developer is suppressed.

  Therefore, in this embodiment, it is possible to efficiently reduce the amount of external additive accumulated between the transfer belt and the cleaning blade contact portion while suppressing toner consumption, reducing toner slipping through the cleaning belt, and transferring the toner onto the transfer belt. It is possible to prevent the toner and the toner wax component from sticking. As a result, it is possible to suppress scratches on the transfer belt caused by toner fixation. In addition, since the rotation speed of the developing device and the transfer belt can be suppressed, the life of the developing device and the transfer belt can be extended.

  Note that a program for the CPU to execute the processing shown in the flowcharts of the respective drawings constitutes a program according to the present invention. As a computer-readable recording medium for recording the program, a semiconductor storage unit, an optical and / or magnetic storage unit, or the like can be used. By using such a program and a recording medium in a system having a configuration different from that of each of the above-described embodiments and causing the CPU to execute the program, substantially the same effect as the present invention can be obtained.

  Although specifically described based on the preferred embodiments, the present invention is not limited to the above-described image forming apparatus, control method and program for the image forming apparatus, and various modifications can be made without departing from the scope of the invention. It goes without saying that.

DESCRIPTION OF SYMBOLS 1 Paper feed tray 2 Paper feed roller 3 Registration roller 4 Registration sensor 5 Transfer belt 6 Developing device 7 Secondary transfer drive roller 8 Transfer belt tension roller 9 Photoconductor 10 Charger 11 Exposure unit 12 Developer 13 Cleaner blade 14 Laser light 15 Primary transfer roller 16 Secondary transfer roller 17 Belt cleaner 18 Paper discharge roller 20 Fixing device 21 Cleaning blade 40 Paddle 41 TM sensor 43 Waste toner full detection sensor 44 Waste toner box 100 Control mechanism portion 101 Control portion 102 ROM
103 RAM
104 Count value storage unit 105 Development device replacement date storage unit 106 Non-volatile memory 107 Rotation time count storage unit 108 Travel distance count storage unit 109 Development device use start date storage unit 111 Photoconductor drive motor 201 Heating roller 202 Pressure roller

JP 2008-317175 A JP 2004-233670 A JP 2008-033286 A JP-A-2005-250215

Claims (11)

At least one image bearing means for forming an electrostatic latent image on the surface;
At least one developing means for developing a developer containing toner and an external additive attached to the outer periphery of the electrostatic latent image to form a toner image;
A transfer means to which the toner image is transferred;
Toner image reading means for reading a toner image formed on the transferred means;
Control means for controlling the formation of a toner image pattern on the transfer receiving means,
The control unit determines a use level based on a use state of at least one of the developing unit and the transferred unit, and faces the toner image reading unit passing unit based on the determined use level. An image forming apparatus that controls the toner image pattern formed on the transfer means and the formation timing of the toner image pattern. The usage level is determined based on at least one of a usage period of the developing unit, a driving time of the developing unit, a driving distance of the developing unit, a rotation time of the transferred unit, and a rotating time of the transferred unit. ,
The height of the use level is at least one length of a use period of the developing unit, a driving time of the developing unit, a driving distance of the developing unit, a rotation time of the transferred unit, and a rotating time of the transferred unit. The image forming apparatus according to claim 1, wherein the height of the image forming apparatus increases with the increase.   3. The control unit according to claim 2, wherein the control unit performs control so that a pattern length in a sub-scanning direction of a toner image pattern formed on the transfer unit increases with the use level. Image forming apparatus.   The control unit determines a timing of forming a toner image pattern formed on the transferred unit based on a usage level of the developing unit having the lowest usage level among the at least one developing unit. The image forming apparatus according to claim 2, wherein the image forming apparatus is controlled.   The control means controls so that an area of a toner image pattern formed on the transferred means increases in a main scanning direction and a sub-scanning direction as the use level is high. The image forming apparatus according to any one of 2 to 4. At least one image carrying step for forming an electrostatic latent image on the surface;
A developing step in which at least one or more developing means develops a developer containing toner and an external additive attached to the outer periphery of the electrostatic latent image to form a toner image;
A transferred step of transferring the toner image to a transferred means;
A toner image reading unit that determines a usage level based on a usage state of at least one of the developing unit and the transferred unit, and reads a toner image formed on the transferred unit based on the determined usage level; A control method for an image forming apparatus, comprising: a toner image pattern formed on the transfer unit facing the passage portion; and a control step for controlling the formation timing of the toner image pattern. In the control step, the usage level is set to at least one of a usage period of the developing unit, a driving time of the developing unit, a driving distance of the developing unit, a rotating time of the transferred unit, and a rotating time of the transferred unit. Based on
The height of the use level is at least one length of a use period of the developing unit, a driving time of the developing unit, a driving distance of the developing unit, a rotation time of the transferred unit, and a rotating time of the transferred unit. The method of controlling an image forming apparatus according to claim 6, wherein the image forming apparatus becomes higher as the image data increases.   8. The control step according to claim 7, wherein the control is performed so that a pattern length in a sub-scanning direction of a toner image pattern formed on the transfer unit increases with the use level. Image forming apparatus control method.   In the control step, a timing of forming a toner image pattern formed on the transferred unit is determined based on a usage level of the developing unit having the lowest usage level among the at least one developing unit. The method of controlling an image forming apparatus according to claim 7 or 8, wherein the control is performed.   2. The control step according to claim 1, wherein the area of the toner image pattern formed on the transfer unit is controlled to increase in the main scanning direction and the sub-scanning direction as the usage level increases. The method for controlling an image forming apparatus according to any one of 7 to 9. Processing to form an electrostatic latent image on the surface;
A process in which at least one developing means develops a developer containing toner and an external additive attached to the outer periphery of the electrostatic latent image to form a toner image;
A process of transferring the toner image to a transfer means;
A toner image reading unit that determines a usage level based on a usage state of at least one of the developing unit and the transferred unit, and reads a toner image formed on the transferred unit based on the determined usage level; A program that causes a computer to execute a toner image pattern formed on the transfer-receiving unit facing the passage and a process for controlling the formation timing of the toner image pattern.

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