JP5834459B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

Patent Document 1 discloses an image carrier, a developing device that develops an electrostatic latent image formed on the image carrier with a developer having toner and a carrier, and a replenishment unit that replenishes the developer with the developer. A supply amount control means for controlling the amount of developer supplied by the supply means; and a control means capable of executing a discharge mode for forcibly discharging the developer in the developing device without forming an image on a recording material. An image forming apparatus comprising:
In the discharge mode, the replenishment amount control means is configured such that the ratio of toner and carrier in the developing device after starting the discharge mode is higher than the ratio of toner and carrier in the developing device when the discharge mode is started. An image forming apparatus is disclosed in which the replenishment amount of the replenishing means is controlled so as to be low.

  Japanese Patent Application Laid-Open No. 2005-228561 discloses a developing device that contains toner and performs development using toner, print execution means that executes printing using the toner, and image stabilization that executes image stabilization processing using the toner. Image processing means, acquisition means for acquiring the amount of staying toner in the developing device, and after printing, toner discharge processing is performed using the amount of staying toner acquired by the acquisition means and the first reference. An image forming apparatus including a toner discharge unit that performs a toner discharge process using the amount of staying toner acquired by the acquisition unit and a second reference after the stabilization process ends is disclosed.

JP 2010-91801 A JP 2009-282443 A

  An object of the present invention is to provide an image forming apparatus capable of replacing a developer during an image forming operation.

  According to a first aspect of the present invention, there is provided an image holding body that holds an image, and a developer supply member that supplies a developer having toner and carrier to the image holding body, and the latent image held by the image holding body A developing device that develops toner, a toner collecting member that collects toner from the developer supply member, and a toner discharge device that discharges toner from the developing device; and development from the developer supply member to the image carrier And a control unit that controls the toner recovery member so as to recover the toner from the developer supply member during supply of the agent.

  The present invention according to claim 2 further includes a voltage applying device that applies a voltage to the toner recovery member, and the controller is configured to move the toner from the developer supply member toward the toner recovery member. The image forming apparatus according to claim 1, wherein the voltage application device is controlled so that a voltage and a voltage in a direction in which toner adhesion is rejected are applied to the toner recovery member.

  According to a third aspect of the present invention, the controller applies the voltage so that the force of the toner collecting member to attract the toner is stronger than the force of the toner retaining portion of the image carrier to attract the toner. The image forming apparatus according to claim 2, wherein the apparatus is controlled.

  The present invention according to claim 4 further includes: a toner supply device that supplies toner to the developing device; and a latent image forming device that forms a latent image on the image holding member, and the control unit includes the toner When the time when the toner is supplied from the supply device to the developing device is equal to or shorter than a predetermined time, or the number of pixels of the latent image formed on the image carrier by the latent image forming device is predetermined. 4. The image forming apparatus according to claim 1, wherein the toner collecting member controls the toner collecting member to collect toner from the developer supply member when the number of pixels is equal to or less than the number of pixels.

  According to a fifth aspect of the present invention, the control unit is configured such that the difference between a time when the toner is supplied from the toner supply device to the developing device and a predetermined time, or the latent image forming device is the image carrier. 5. The image forming apparatus according to claim 4, wherein a time for the toner collecting member to collect the toner from the developer supply member is determined in accordance with a difference between the number of pixels of the latent image formed in a predetermined number and a predetermined number of pixels. It is.

  According to a sixth aspect of the present invention, the developer supply member rotates when the developer is supplied to the image carrier, and the toner recovery member is configured to recover the toner from the developer supply member. The image forming apparatus according to claim 1, wherein the image forming apparatus rotates with a peripheral speed difference from a developer supply member.

  The present invention according to claim 7 is the image forming apparatus according to any one of claims 1 to 6, wherein the toner discharging device is detachable from the developing device.

  According to the first aspect of the present invention, it is possible to provide an image forming apparatus capable of replacing toner during an image forming operation.

  According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, an image forming apparatus capable of electrostatically collecting toner from a developer supply member is provided. be able to.

  According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, the toner can be efficiently recovered from the developer supply member as compared with the case without the present configuration. It is possible to provide an image forming apparatus capable of performing the above.

  According to the fourth aspect of the present invention, in addition to the effects of the first aspect of the present invention according to any one of the first to third aspects, the toner is collected at an appropriate timing as compared with the case without the present configuration. It is possible to provide an image forming apparatus capable of performing the above.

  According to the fifth aspect of the present invention, in addition to the effects of the first aspect of the present invention according to any one of the first to third aspects, the time for collecting the toner can be appropriately set as compared with the case without the present configuration. An image forming apparatus that can be defined can be provided.

  According to the sixth aspect of the present invention, in addition to the effects exhibited by the present invention according to any one of the first to fifth aspects, the toner can be efficiently recovered as compared with the case without the present configuration. It is possible to provide an image forming apparatus capable of performing the above.

  According to the seventh aspect of the present invention, in addition to the effects exhibited by the present invention according to any one of the first to sixth aspects, an image forming apparatus that is easier to maintain than the case without the present configuration is provided. Can be provided.

1 is a diagram illustrating an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged view illustrating an image forming unit included in the image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram for explaining a relationship among potentials of a photoconductor, a developing roll, and a collecting roll in the image forming apparatus shown in FIG. 1. FIG. 2 is a block diagram illustrating a control unit included in the image forming apparatus illustrated in FIG. 1. 3 is a first flowchart illustrating an operation of the image forming apparatus illustrated in FIG. 1. 6 is a second flowchart for explaining the operation of the image forming apparatus shown in FIG. 1. FIG. 5 is a block diagram illustrating a control unit included in an image forming apparatus according to a second embodiment of the present invention. 6 is a flowchart illustrating an operation of an image forming apparatus according to a second embodiment of the present invention. FIG. 4 is an enlarged view illustrating an image forming unit included in an image forming apparatus according to a comparative example.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to a first embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 12, and an image forming unit 100 and a control unit 500 are provided in the image forming apparatus main body 12.

  The image forming unit 100 is used as an image holding member that holds an image. The image forming unit 100 is formed on the photosensitive member 102, for example, a cylindrical photosensitive member 102, a developing device 130 that develops a latent image held by the photosensitive member 102, and the photosensitive member 102. And a transfer device 110 that transfers the toner image to a sheet. Details of the image forming unit 100 will be described later.

  In the image forming apparatus main body 12, a fixing device 180 that fixes the toner image transferred onto the paper by the transfer device 110 to the paper, and a toner supply device 200 that supplies toner to the developing device 130 are disposed. In addition, a conveyance path 400 for conveying a sheet used as a recording medium is formed in the image forming apparatus main body 12.

  The fixing device 180 fixes, for example, toner on paper using heat. As the fixing device 180, for example, a flash-type fixing device is used.

  Further, the image forming apparatus main body 12 has an insertion hole 14 used for inserting paper into the image forming apparatus main body 12 and a discharge hole 16 used for discharging paper from the image forming apparatus main body 12. Is formed.

  Further, on the outside of the image forming apparatus main body 12, a paper storage unit 480 that stores paper before image formation and a paper discharge unit 490 that discharges paper after image formation is provided. ing. In the image forming apparatus 10, for example, a long recording paper such as a continuous form is used, and the long recording paper is stored in the paper storage unit 480 in a folded state. In the image forming apparatus 10, the long sheet on which the image is formed is discharged to the sheet discharge unit 490 in a folded state.

  The conveyance path 400 is a conveyance path that is used to convey a sheet from the insertion hole 14 to the discharge hole 16. In the image forming apparatus main body 12, the conveyance path 400 is sequentially along the conveyance path 400 from the upstream side in the sheet conveyance direction. A delivery device 410 that feeds the paper toward the downstream side, a guide plate 414 that guides the paper, the photosensitive member 102 and the transfer device 110, a guide plate 416 that guides the paper, a fixing device 180, and a paper transport toward the discharge hole 16 A transport roll 418 is disposed.

  The toner supply device 200 is connected to the toner storage container 204 that stores the toner and the developing device 130, and is driven by driving transmission from the toner supply motor 208 to remove the toner in the toner storage container 204. The toner is conveyed to the developing device 130 and supplied to the developing device 130.

FIG. 2 shows the image forming unit 100.
The image forming unit 100 forms, for example, a monochromatic image and employs an electrophotographic system. As described above, the image forming unit 100 includes the photoconductor 102, the developing device 130, and the transfer device 110. The image forming unit 100 is further charged by the charging device 104 and the charging device 104 that uniformly charges the photoconductor 102. The surface of the photoconductor 102 is irradiated with light, and the latent image forming device 106 that forms an electrostatic latent image on the surface of the photoconductor 102 and the photoconductor 102 after the toner image is transferred onto the paper by the transfer device 110 are cleaned. A cleaning device 114 for discharging the toner, and a toner discharging device 150 for discharging the toner from the developing device 130.

  The developing device 130 includes a developing device main body 132. The developing device main body 132 is used as a developer conveying member 134, a developer conveying member 136, and a developer supply member that supplies developer to the photosensitive member 102. A developing roll 138 and a toner density sensor 140. The developing device main body 132 contains a developer in which toner and a carrier are mixed.

  The developer conveying member 134 conveys the developer from the near side to the far side in FIG. 2 by rotating in the arrow direction shown in FIG. The developer transport member 136 rotates in the direction of the arrow shown in FIG. 2 to transport the developer from the back side to the front side in FIG. By being conveyed by the developer conveying member 134 and the developer conveying member 136, the toner and the carrier are agitated.

  The developing roll 138 rotates in the direction of the arrow shown in FIG. A developing bias applying device 142 having a high voltage power source is connected to the developing roll 138, and a developing bias is applied from the developing bias applying device 142.

  The toner concentration sensor 140 detects the concentration of toner in the developer stored in the developing device main body 132.

  The toner discharge device 150 has a toner discharge device main body 152, a recovery roll 154 used as a toner recovery member for recovering only toner from the developing roll 138 in the toner discharge device main body 152, and the surface of the recovery roll 154 A scraping member 156 that scrapes off the toner from the toner discharging unit, and a transport member 158 that transports the toner scraped off by the scraping member 156 to the outside of the toner discharging apparatus main body 152.

  The collection roll 154 can collect the toner from the development roll 138 during the supply of the developer from the development roll 138 to the photoreceptor 102, and the collection roll 154 is connected to the collection roll motor via the drive transmission mechanism 162. 164 is connected. The collection roll 154 receives drive transmission from the collection roll motor 164 and rotates, for example, in a direction different from that of the development roll 138 as indicated by an arrow in FIG. Instead of rotating the collecting roll 154 in a direction different from that of the developing roll 138, the collecting roll 154 may be rotated in the same direction as the developing roll 138. The collection roll 154 preferably rotates with a difference in peripheral speed from the development roll 138 when the toner is collected from the development roll 138. Instead of rotating the collection roll 154 in response to drive transmission from the collection roll motor 164, the collection roll 154 is rotated in conjunction with the rotation of the development roll 138 as drive transmission from the rotation mechanism of the development roll 138. Also good.

  The recovery roll 154 is connected to a recovery bias application device 168 having a high voltage power supply. The recovery bias application device 168 applies a recovery bias when collecting toner, and applies a non-recovery bias when toner recovery is not performed. The

  The developer discharging device 150 can be attached to and detached from the developing device 130.

  FIG. 3 illustrates the relationship among the potentials of the photosensitive member 102, the developing roll 138, and the collection roll 154. As shown in FIG. 3, the surface of the photoreceptor 102 is charged to −400 V, for example, by the charging device 104. Then, the potential of the portion where the latent image is formed by the latent image forming device 106 is, for example, −100V. For example, a developing bias of −200 V is applied to the developing roll 138 by the developing bias applying device 142. For this reason, some of the negatively charged toner in the developer adheres to the portion of the photoreceptor 102 where the latent image is formed, and the positively charged carrier does not adhere to the photoreceptor 102. The remaining toner is retained on the developing roll 138 and is peeled from the developing roller 138 in the developing device main body 132 and is transported by the developer transport member 134 and the developer transport member 136 to be mixed with new toner. And stirred again.

  A voltage of, for example, −100 V is applied to the recovery roll 154 by the recovery bias applying device 168. Then, only the toner in the developer adhering to the developing roll 138 moves to the collecting roll 154, and only the toner is collected from the developing roll 138 to the collecting roll 154. As described above, the collection roll 154 collects only the toner from the developing roll 138 by applying the voltage in the direction in which only the toner moves from the developing roll 138 toward the collecting roll 154 by the collection bias applying device 168. Here, the voltage (−100V) applied to the recovery roll 154 is a portion where the latent image of the photoconductor 102 is formed, and is equal to the potential (−100V) of the portion where the negatively charged toner adheres. . When toner collection is not required, for example, −400 V is applied to the collection roll 154 by the collection bias applying device 168. Then, a voltage in a direction in which toner adhesion is rejected from the collection roll 154 toward the developing roll 138 is applied by the collection bias application device 168, so that the toner can be prevented from adhering to the collection roll 154. Here, the voltage (−400 V) applied to the collecting roll 154 is a portion where a latent image is not formed on the photosensitive member 102, and is equivalent to the potential (−400 V) of the background portion where no toner adheres.

  The voltage applied to the collecting roll 154 is changed to be equal to the potential of the portion where the latent image of the photosensitive member 102 is formed and the toner adheres, and the toner of the photosensitive member 102 is applied to the collecting roller 154. A voltage may be applied so that the force of the collecting roll 154 to attract the toner is stronger than the force of the holding portion to attract the toner. For example, in the first embodiment, a bias of −50 V may be applied to the collection roll 154.

  The voltage is applied to the collection roll 154 by the control unit 500 (see FIG. 1) controlling the collection bias application device 168.

  FIG. 4 shows the control unit 500. The control unit 500 includes a control circuit 502 including, for example, a CPU, and image data is input to the control circuit 502 via the communication interface 504. Further, the output from the toner density sensor 140 is input to the control circuit 502. Further, the control circuit 502 controls the toner supply motor 208, the recovery bias applying device 168, and the recovery roll motor 164. In addition to the recovery bias applying device 168 and the recovery roll motor 164, each device constituting the image forming unit 100 is controlled by an output from the control circuit 502.

  Further, the control circuit 502 counts the toner supply time, which is a time that can be measured by, for example, the driving time of the toner supply motor 208 and the toner supply device 200 supplies the toner to the developing device 130. A supply time counter 510 is connected. The control circuit 502 also includes a toner supply motor 208 from the time when the toner discharging device 150 discharges toner from the developing device 130 to the time when the toner discharging device 150 discharges toner inside the developing device 130. Is connected to a supply time memory 512 that stores a supply time that is a drive time. The supply time can be set to a predetermined time, for example.

  When the control circuit 502 determines from the output of the toner density sensor 140 that the developer concentration in the developing device 130 is lower than a predetermined value, the toner supply motor 208 is driven to drive the toner supply device 200. The toner is supplied to the developing device 130.

  FIG. 5 is a flowchart for explaining the operation of the image forming apparatus 10 according to the first embodiment. When image data is input and a series of operations starts as shown in FIG. 5, in a first step S 12, the control circuit 502 determines that the toner supply time counted by the supply time counter 510 is the supply time memory. It is determined whether or not the time is equal to or shorter than the predetermined time stored in 512. If it is not determined that the toner supply time by the toner supply device 200 is equal to or less than the predetermined time stored in the supply time memory 512, the process proceeds to step S100, and the toner supply time by the toner supply device 200 is determined. If it is determined that the time is less than the predetermined time stored in the supply time memory 512, the process proceeds to step S200.

  In step S100, the control circuit 502 controls the image forming unit 100 to cause the image forming unit 100 to perform image formation in the normal mode. Here, the normal mode is an image forming mode in which the toner is not discharged from the developing device 130 by the toner discharging device 150 while the developer is being supplied from the developing device 130 to the photosensitive member 102. In an image forming mode in which toner is not discharged, a non-collecting bias is applied to the collecting roll 154 by the collecting bias applying device 168. When step S100 is completed, the process proceeds to step S20.

  In step S200, the control circuit 502 controls the image forming unit 100 to cause the image forming unit 100 to form an image in the toner discharge mode. Here, the toner discharge mode is an image forming mode in which toner is discharged from the developing device 130 by the toner discharging device 150 while the developer is being supplied from the developing device 130 to the photosensitive member 102. Details of image formation in the toner discharge mode in step S200 will be described later. When step S200 is completed, the process proceeds to step S20.

  In step S20, it is determined from the input image data whether or not the series of processes is related to the last image data. If the last image data, the series of processes is terminated. If so, the process returns to step S12.

  FIG. 6 is a flowchart showing the operation of the toner discharge device 150 during image formation in the toner discharge mode in step S200. In step S12 (see FIG. 5), it is determined that the toner supply time by the toner supply device 200 is equal to or less than the predetermined time stored in the supply time memory 512, and the toner discharge mode (step S200) starts. In the next step S202, the control circuit 502 controls the recovery bias applying device 168 to cause the recovery bias applying device 168 to switch the application to the recovery roll 154 from the non-recovery bias to the recovery bias.

  In the next step S204, the control circuit 502 controls the collection roll motor 164 to start the rotation of the collection roll 154.

  In the next step S206, after confirming that a predetermined time has passed, the process proceeds to the next step S208. Instead of confirming that a predetermined time has passed in step S206, the difference between the time when the toner is supplied from the toner supply device 200 to the developing device 130 and the predetermined time stored in the supply time memory 512 Accordingly, the time for collecting the toner from the developing roll 138 may be calculated and determined, and it may be confirmed whether or not the determined time has elapsed.

  In step S208, the control circuit 502 controls the recovery bias applying device 168 to cause the recovery bias applying device 168 to switch the application to the recovery roll 154 from the recovery bias to the non-recovery bias. In the next step S210, the control circuit 502 controls the collection roll motor 164 to stop the rotation of the collection roll 154, thereby ending a series of toner discharge modes.

  FIG. 7 shows a control unit 500 included in the image forming apparatus according to the second embodiment of the present invention. In the image forming apparatus 10 according to the first embodiment described above, the control circuit 502 is supplied with a supply time counter 510 that counts a toner supply time that is a time during which the toner supply device 200 supplies toner to the developing device 130, After the toner is discharged from the developing device 130 by the toner discharging device 150, the toner supply motor 208 is driven until the toner is discharged from the developing device 130 by the toner discharging device 150. A supply time memory 512 to be stored was connected. On the other hand, in the second embodiment, a pixel number counter 520 and a pixel number memory 522 are connected to the control circuit 502.

  A pixel number counter 520 counts the number of pixels of image data input via the communication interface 504. The pixel number memory 522 is an image of image data input after the toner discharging device 150 discharges the toner from the developing device 130 until the toner discharging device 150 discharges the toner in the developing device 130 next. I remember the number. The number of pixels to be stored can be, for example, a predetermined number of pixels.

  FIG. 8 is a flowchart for explaining the operation of the image forming apparatus according to the second embodiment. In the image forming apparatus 10 according to the first embodiment described above, the control circuit 502 stores the toner supply time by the toner supply device 200 counted by the supply time counter 510 in the supply time memory 512 in the first step S12. It was determined whether or not the predetermined time was exceeded (see FIG. 5). On the other hand, in the second embodiment, the control circuit 502, in the first step S14, inputs the number of pixels input through the communication interface 504 and stored in the pixel number counter 520, that is, latent image formation. It is determined whether or not the number of pixels of the latent image formed on the photosensitive member 102 by the device 106 is equal to or greater than a predetermined number of pixels stored in the pixel number memory 522.

  If it is not determined that the number of pixels of the latent image formed on the photosensitive member 102 by the latent image forming apparatus 106 is equal to or less than the predetermined number of pixels stored in the pixel number memory 522, the process proceeds to step S100. If it is determined that the number of pixels of the latent image formed on the photosensitive member 102 by the image forming apparatus 106 is equal to or less than the predetermined number of pixels stored in 522, the process proceeds to step S200.

  Further, in the image forming apparatus 10 according to the first embodiment described above, the application of the collection bias to the collection roll 154 is started and rotation of the collection roll 154 is started in step S206 (see FIG. 6). Instead of confirming that a predetermined time has passed, a difference between the time when the toner is supplied from the toner supply device 200 to the developing device 130 and the predetermined time stored in the supply time memory 512 is determined. It was possible to calculate the time for collecting the toner from the developing roll 138 and check whether or not the calculated time has elapsed. On the other hand, in the second embodiment, it is confirmed that the application of the collection bias to the collection roll 154 is started and a predetermined time has elapsed since the rotation of the collection roll 154 has started. Instead, the difference between the number of pixels counted by the pixel number counter 520, that is, the number of pixels formed on the photosensitive member 102 by the latent image forming device 106, and the predetermined number of pixels stored in the pixel number memory 522. Accordingly, the time for collecting the toner from the developing roll 138 may be calculated, and it may be confirmed whether or not the calculated time has elapsed.

  Since the configuration and control of the image forming apparatus according to the second embodiment are the same as those of the image forming apparatus 10 according to the above-described first embodiment except for the portions described above, the description of the same portions will be described. Omitted.

  FIG. 9 is an enlarged view of the image forming unit 100 included in the image forming apparatus according to the comparative example. In the first embodiment and the second embodiment described above, the image forming apparatus has the toner discharge device 150, and the toner in the developing device 130 is discharged to the outside of the developing device 130 using the toner discharge device 150. It was. On the other hand, the image forming apparatus according to this comparative example does not include the toner discharge device 150. For this reason, in the image forming apparatus according to this comparative example, when the toner in the developing device 130 is discharged, for example, because the ratio of the deteriorated toner in the developing device 130 is reduced, for example, a sheet of black solid image or the like In other words, a large amount of toner is transferred to form an image.

  In addition, in the image forming apparatus according to this comparative example, as in the image forming apparatuses according to the first embodiment and the second embodiment described above, the toner discharge device 150 is used during an image forming operation, that is, development. During the supply of the developer from the roll 138 to the photosensitive member 102, the toner cannot be discharged from the developing device 130. For this reason, in order to replace the toner in the developing device 130, for example, a large amount of paper on a black solid image or the like is formed after the end of image formation on a long recording paper such as a continuous form. It is necessary to form an image to which toner is transferred. For this reason, while the developer in the developing device 130 is replaced, for example, an image in which a large amount of toner is transferred to a sheet such as a black solid image must be formed. Image formation or the like cannot be performed.

  As described above, the present invention can be used at least in an image forming apparatus such as a printer, a facsimile machine, and a copying machine.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 102 ... Photoconductor 106 ... Latent image forming apparatus 130 ... Developing apparatus 138 ... Developing roll 140 ... Toner density sensor 150 ... Toner discharging apparatus 154 ... Collection roll 164: Collection roll motor 168 ... Collection bias application device 200 ... Toner supply device 500 ... Control unit 510 ... Supply time counter 512 ... Supply time memory 520 ... Pixel number counter 522 ... Pixel number memory

Claims (5)

An image carrier for holding an image;
A developing device for developing a latent image held by the image carrier, the developer supply member supplying a developer having toner and carrier to the image carrier;
A toner discharge device that has a toner recovery member for recovering toner from the developer supply member, and discharges the toner from the development device;
A voltage applying device for applying a voltage to the toner image collecting member;
A control unit that controls to collect toner from the developer supply member during supply of the developer from the developer supply member to the image carrier;
Have
The controller is
The toner holding part of the image holding member is attracted so that the toner containing toner having the same polarity and the same potential as the toner used for developing the latent image is collected from the developer supply member. The voltage applying device is controlled so that the force is the same as the force of attracting the toner of the toner collecting member, or the toner of the toner collecting member is more than the force of attracting the toner of the portion of the image holding member that holds the toner. Controlling the voltage application device so that the pulling force becomes stronger ,
The voltage application device is controlled so that a voltage in a direction in which the toner moves from the developer supply member toward the toner collection member and a voltage in a direction in which toner adhesion is rejected are applied to the toner collection member. to <br/> image forming apparatus. A toner supply device for supplying toner to the developing device;
A latent image forming apparatus for forming a latent image on the image carrier;
Further comprising
The controller is configured to detect a pixel of a latent image formed on the image carrier by the latent image forming apparatus when the time when the toner is supplied from the toner supply apparatus to the developing device is equal to or less than a predetermined time. If the number is less than a predetermined number of pixels previously determined, the toner collecting member is an image forming apparatus according to claim 1 wherein the control so as to collect the toner from the developer supply member. The control unit includes a difference between a time when the toner is supplied from the toner supply device to the developing device and a predetermined time, or the number of pixels of the latent image formed on the image carrier by the latent image forming device. The image forming apparatus according to claim 2 , wherein a time for the toner collecting member to collect toner from the developer supply member is determined according to a difference from a predetermined number of pixels. The developer supply member rotates when the developer is supplied to the image carrier, and the toner recovery member has a peripheral speed difference from the developer supply member when recovering toner from the developer supply member. the image forming apparatus according to any one of claims 1 to 3 rotates. The toner discharging device, the developing device in a detachable and is claims 1 to 4 The image forming apparatus according to any one.

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