Image forming apparatus, program, and method for controlling image forming apparatus

Abstract

To provide an image forming apparatus that can determine the timing to end a toner recovery mode.SOLUTION: An image forming apparatus 1 comprises: a photoreceptor drum 4 on which a toner image is formed; a developing unit 5 that develops the photoreceptor drum 4; a cleaner 8 that removes toner from the photoreceptor drum 4; and a control unit 100 that executes a toner recovery mode for removing the toner from the photoreceptor drum 4 without transferring the toner image to a sheet. When the control unit 100 determines that the amount of toner that can be supplied to the photoreceptor drum 4 reaches a predetermined amount for ending the toner recovery mode, on the basis of toner amount information that changes according to the amount of toner that can be supplied to the photoreceptor drum 4, the control unit ends the toner recovery mode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, a program, and a control method for the image forming apparatus in which a toner collection mode is executed.

Background Art

[0002] The work on used maintenance parts of image forming apparatuses has started. Consideration has also begun to attach a label indicating that it is a genuine used maintenance part, and consideration of commercialization has started.

[0003] On the other hand, third-party toner refill products are also on the market. In order to restore the image quality as used maintenance parts, it is necessary to clean and remove the toner provided by a third party remaining in the image forming apparatus. When cleaning and removing the toner, for the toner bottle, it may be replaced. In contrast, for the toner remaining in parts of the image forming apparatus that are not assumed to be detached or replaced in normal maintenance, it is necessary to perform a cleaning and removing operation manually, which is very time-consuming.

[0004] Therefore, Patent Document 1 proposes having a toner collection mode in which the toner transferred to the photosensitive drum is collected by a cleaning means without being transferred to a recording medium.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As a method for determining the timing to end the toner collection mode, in a one-component development system, it has been proposed to determine based on the detection level of a toner detection sensor. However, with a sensor for detecting the remaining toner amount in the developing unit, it is impossible to accurately detect whether all the toner in the developing unit and the like has been collected. For this reason, there is a possibility that toner remains in the developing unit and the like. On the other hand, there is a possibility that the toner collection mode is continued even though the toner in the developing unit and the like has disappeared. If the toner collection mode is continued, in a two-component development system, carrier adhesion will occur, increasing the possibility of damaging the photoreceptor and the transfer belt.

[0007] The present invention has been made to solve such problems, and provides an image forming apparatus capable of determining the timing to end the toner collection mode. Further, a program capable of determining the timing to end the toner collection mode and a control method for the image forming apparatus are provided.

Means for Solving the Problems

[0008] To solve the above-described problems, the present invention includes a storage unit that stores toner, an image carrier unit on which a toner image is formed, a developing unit that develops the image carrier unit, a removing unit that removes toner from the image carrier unit, a detection unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier unit, and a control unit that executes a toner collection mode for removing toner from the image carrier unit without transferring the toner image to a recording medium. The control unit, based on the toner amount information detected by the detection unit, determines that the amount of toner that can be supplied to the image carrier unit has reached a predetermined amount for ending the toner collection mode, and then ends the toner collection mode. This is an image forming apparatus.

[0009] Further, the present invention includes an image carrier on which a toner image is formed, a removing unit that removes toner from the image carrier, and a detecting unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier. The present invention is a program executed by a control unit of an image forming apparatus in which a toner recovery mode is executed to remove toner from the image carrier without transferring the toner image to a recording medium. The program causes the control unit to execute a step of detecting toner amount information by the detecting unit, and a step of ending the toner recovery mode when it is determined based on the toner amount information detected by the detecting unit that the amount of toner that can be supplied to the image carrier has reached a predetermined amount for ending the toner recovery mode.

[0010] Furthermore, the present invention is a control method for an image forming apparatus including an image carrier on which a toner image is formed, a removing unit that removes toner from the image carrier, and a detecting unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier. The toner recovery mode is executed to remove toner from the image carrier without transferring the toner image to a recording medium. The control method includes a step of detecting toner amount information by the detecting unit, and a step of ending the toner recovery mode when it is determined based on the toner amount information detected by the detecting unit that the amount of toner that can be supplied to the image carrier has reached a predetermined amount for ending the toner recovery mode.

Advantages of the Invention

[0011] In the present invention, by recovering toner while directly or indirectly detecting the amount of residual toner, it is possible to accurately detect the timing when the recovery is completed. Thereby, it is possible to suppress the occurrence of insufficient recovery of residual toner. Further, it is possible to suppress continuing the toner recovery mode even when the residual toner has run out. As a result, it is possible to efficiently recover toner without damaging surrounding units.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0013] Hereinafter, with reference to the drawings, embodiments of the image forming apparatus, program, and control method of the image forming apparatus of the present invention will be described.

[0014] <Configuration Example of the Image Forming Apparatus and Program of the Present Embodiment> FIG. 1 is an overall configuration diagram showing an example of the image forming apparatus of the present embodiment. The image forming apparatus 1 integrates functions such as a copying machine, a printer, a facsimile machine, and an image reader. Such an image forming apparatus 1 is called an MFP (Multi-functional Peripheral).

[0015] The image forming apparatus 1 includes an automatic document feeder (ADF) 1A, a flatbed scanner 1B, a printer unit 1C, and a paper feeding unit 1D.

[0016] The automatic document feeder 1A conveys the document (sheet) set on the document tray to the reading position of the scanner 1B. The scanner 1B reads an image from the sheet-like document conveyed from the automatic document feeder 1A or various documents set on the platen glass and generates image data.

[0017] In a print job, the printer unit 1C forms color or monochrome images on one or both sides of a sheet of paper (recording sheet, recording medium) P. Print jobs include copying, network printing (PC printing), facsimile reception, and box printing. For example, in a copy job, an image is formed based on the image data generated by the scanner 1B.

[0018] In a configuration where the printer unit 1C forms color images, it is equipped with an electrophotographic tandem-type printer engine. The printer engine includes four imaging units 3Y, 3M, 3C, 3K, a print head 6, an intermediate transfer belt 10, and the like.

[0019] The imaging units 3Y to 3K each have devices such as a photosensitive drum 4, a charging roller 2, a developing unit 5, a toner supply unit 7, a cleaner 8, and a cleaning roller 9. Since the basic configurations of the imaging units 3Y to 3K are the same, they may be referred to as "imaging unit 3" without distinction hereinafter.

[0020] The print head 6 emits a laser beam LB as light for performing pattern exposure on each photosensitive drum 4 of the imaging units 3Y to 3K. The laser beam LB is a so-called Gaussian beam whose radiation intensity approximately exhibits a Gaussian distribution. The photosensitive drum 4 is an example of an image carrier.

[0021] The intermediate transfer belt 10 is an example of an image carrier and is a transfer member onto which a toner image is primarily transferred. The intermediate transfer belt 10 is wound and rotated between a pair of rollers. Inside the intermediate transfer belt 10, primary transfer rollers 11 are arranged for each of the imaging units 3Y, 3M, 3C, 3K.

[0022] The printer unit 1C includes a toner adhesion amount detection sensor 20 and a cleaner 21. The toner adhesion amount detection sensor (IDC sensor) 20 is an example of a detection unit, and detects the amount of toner transferred onto the intermediate transfer belt 10. The toner adhesion amount detection sensor 20 is, for example, a reflection type optical sensor, and is provided facing the intermediate transfer belt 10. The cleaner 21 removes and collects the toner transferred onto the intermediate transfer belt 10 from the intermediate transfer belt 10. The cleaners 8 and 21 are examples of removal units.

[0023] The paper feeding unit 1D has a plurality of paper feeding cassettes 12a, 12b, 12c, and takes out the paper P from any of the selected paper feeding cassettes and supplies it to the upper printer unit 1C.

[0024] In the color printing mode, the imaging units 3Y to 3K sequentially form toner images of four colors: Y (yellow), M (magenta), C (cyan), and K (black). The four-color toner images are sequentially primary-transferred onto the rotating intermediate transfer belt 10. For the four-color toner images, first the Y toner image is transferred, and then the M toner image, C toner image, and K toner image are sequentially transferred so as to overlap it. When the primary-transferred toner image faces the secondary transfer roller 16, it is secondary-transferred onto the paper P that has been conveyed from the paper feeding unit 1D via the timing roller 15. Thereafter, the paper P is discharged by the separating member 18 and sent out to the paper discharge tray 19 through the inside of the fixing device 17. When passing through the fixing device 17, the toner image is fixed onto the paper P by heating and pressurization.

[0025] The image forming apparatus 1 includes a control unit 100 that controls the whole, a power supply unit 200 that supplies power to each unit, and the like.

[0026] The image forming apparatus 1 has paper feeding rollers 13a, 13b, 13c that supply the paper P to the upper printer unit 1C for the paper feeding cassettes 12a, 12b, 12c of the paper feeding unit 1D, respectively. The paper feeding rollers of each cassette are rotationally driven using a paper feeding motor (not shown) as a common drive source, and convey the paper P one by one from the stack of papers loaded in the cassette.

[0027] Figure 2A is a cross-sectional view showing an example of the configuration of the toner supply unit and the developing device according to the present embodiment, and Figure 2B is a cross-sectional view showing an example of the configuration of the developing device according to the present embodiment.

[0028] The developing devices 5 and the toner supply units 7 of the respective imaging units 3Y to 3K have different colors of the developer used. However, since the configurations are basically the same, the developing device 5C and the toner supply unit 7C of the imaging unit 3C will be described below. The description of the developing devices 5 and the toner supply units 7 of the other imaging units 3Y, 3M, and 3K will be omitted. In addition, in Figure 2A, hatching is omitted for the toner and the developer.

[0029] The toner supply unit 7C includes a toner cartridge 71, a toner bottle 71b, a hopper 72, a spiral roller 721, and a toner supply motor 73, etc. The toner supply unit 7C supplies the cyan (C) toner E stored in the toner cartridge 71 to the developing device 5C according to the instruction of the control unit 100. The toner cartridge 71 and the toner bottle 71b can be detachably attached to the hopper 72.

[0030] The hopper 72 is provided with a spiral roller 721 inside the cylindrical portion 724. Further, the hopper 72 is provided with an opening 723 at the upper part of the circumferential surface at one end in the axial direction, and communicates with the toner cartridge 71 mounted on the upper part thereof through the opening 723. Furthermore, the toner cartridge 71 is provided with an openable and closable shutter 723a. When the shutter 723a opens, the toner E is supplied from the toner bottle 71b to the toner cartridge 71. Also, when the shutter 723a closes, the supply of the toner E from the toner bottle 71b is stopped.

[0031] The spiral roller 721 has spiral blades provided on the circumferential surface of the rotating shaft member. The spiral roller 721 rotates by receiving the driving force of the toner supply motor 73. The spiral roller 721 conveys the toner E that has moved by its own weight from the toner cartridge 71 mounted on the hopper 72 into the hopper 72 in the direction of the arrow. The spiral roller 721 supplies the toner E to the developing unit 5C via the toner supply port 722 and the toner receiving port 98.

[0032] The toner supply section 7C is provided with a toner supply port 722 at the end on the downstream side (opposite to the opening 723) of the above-described toner conveyance direction. Further, the toner receiving port 98 is provided in the housing 50 of the developing unit 5C facing the toner supply port 722.

[0033] The developing unit 5C is an example of a developing section and includes a housing 50, a developing roller 51, a supply screw 52, a stirring screw 53, a toner density sensor 54, etc. The housing 50, the developing roller 51, the supply screw 52, and the stirring screw 53 are elongated along the axial direction of the photosensitive drum 4C.

[0034] The housing 50 is partitioned into an upper supply chamber 58 and a lower stirring chamber 59 via a partition wall 57. The supply chamber 58 and the stirring chamber 59 are formed in an elongated cylindrical shape along the axial direction of the partition wall 57. The supply chamber 58 and the stirring chamber 59 communicate with each other via a first communication passage 93 provided at one axial end side of the partition wall 57. Further, the supply chamber 58 and the stirring chamber 59 communicate with each other via a second communication passage 94 provided at the other axial end side. The developing agent D is accommodated in the supply chamber 58 and the stirring chamber 59.

[0035] The developing roller 51 is provided at the opening 50a of the housing 50 in the supply chamber 58. The opening 50a faces the photosensitive drum 4C. The developing roller 51 includes a cylindrical developing sleeve 511 and a magnet roller 512 inserted axially inside the developing sleeve 511.

[0036] The magnet roller 512 is provided such that portions formed with a plurality of magnetic poles, for example, N poles and S poles, are arranged in order alternately in the circumferential direction. The axial end portions of the magnet roller 512 are fixed to the housing 50 so as not to rotate. Each of the magnetic poles extends along the axial direction.

[0037] The developing sleeve 511 faces the photosensitive drum 4C through the opening 50a of the housing 50. The developing sleeve 511 is held rotatably by the housing 50 while the portion facing the photosensitive drum 4C is exposed from the opening. The developing sleeve 511 rotates around the stationary magnet roller 512 while holding (carrying) the developer D on the surface by the magnetic force of the magnet roller 512.

[0038] The supply screw 52 is provided at a position facing the developing roller 51 in the supply chamber 58. The supply screw 52 is provided with spiral blades along the outer peripheral surface of the rotating shaft. The axial end portions of the supply screw 52 are rotatably supported by both side walls of the housing 50 via bearing members (not shown). The supply screw 52 rotates to supply the developer D in the supply chamber 58 to the developing roller 51 while conveying it along the axial direction.

[0039] The agitation screw 53 is provided in the agitation chamber 59. The agitation screw 53 is provided with spiral blades along the outer peripheral surface of the rotating shaft. The axial end portions of the agitation screw 53 are rotatably supported by both side walls of the housing 50 via bearing members (not shown). The agitation screw 53 rotates to agitate the developer D in the agitation chamber 59 while conveying it in a direction opposite to the developer conveyance direction by the supply screw 52.

[0040] Gears 55 are attached to the shaft portions on the rear side of the apparatus for the developing roller 51, the supply screw 52, and the agitation screw 53, respectively. The developing roller 51, the supply screw 52, and the agitation screw 53 rotate by the driving force from the developing motor 56 being transmitted through the meshing of these gears 55.

[0041] When the developing roller 51, the supply screw 52, and the agitation screw 53 rotate, the developer D in the supply chamber 58 is conveyed in the direction indicated by the arrow X1 by the supply screw 52. Also, the developer D in the supply chamber 58 is supplied to the developing roller 51 during its conveyance. When the developer D in the supply chamber 58 is conveyed by the supply screw 52 and reaches the second communication passage 94, it is conveyed through the second communication passage 94 to the agitation chamber 59.

[0042] The developer D conveyed to the agitation chamber 59 is conveyed in the direction indicated by the arrow X2 (opposite to the X1 direction) by the agitation screw 53. When the developer D in the agitation chamber 59 is conveyed by the agitation screw 53 and reaches the first communication passage 93, it is conveyed through the first communication passage 93 to the supply chamber 58. Thereby, the developer D is circulated and conveyed within the housing 50.

[0043] The toner replenished to the developing device 5C from the hopper 72 is sent to the supply chamber 58 via the toner inlet 98. The toner sent to the supply chamber 58 is sent to the agitation chamber 59 through the second communication passage 94 together with the developer D conveyed by the supply screw 52 within the supply chamber 58. Then, the toner sent to the agitation chamber 59 together with the developer D is conveyed while being agitated by the agitation screw 53.

[0044] The toner density sensor (TCR sensor) 54 is an example of a detection unit, and detects toner amount information that changes according to the amount of toner that can be supplied to the photosensitive drum 4 and the intermediate transfer belt 10. The toner density sensor 54 is provided on the wall surface of a portion corresponding to the bottom surface on the downstream side in the developer conveyance direction in the agitation chamber 59. The toner density sensor 54 is, for example, embedded in the wall surface of the agitation chamber 59, does not contact the agitation screw 53, and does not interfere with the rotation of the agitation screw 53.

[0045] The toner density sensor 54 is a magnetic sensor that detects the magnetic permeability of the developer D (toner and carrier) being conveyed in the agitation chamber 59, for example, from a change in the inductance of a coil. From the magnetic permeability of the developer D detected by the toner density sensor 54, the ratio of the carrier (T / C ratio), which is a magnetic substance contained in the developer D, is detected. Thereby, indirectly, the ratio of the toner to the developer D, that is, the toner density, is obtained. For example, when the carrier ratio contained in the developer is low, it is detected that the toner ratio is high. On the other hand, when the carrier ratio contained in the developer is high, it is detected that the toner ratio is low. And the detection signal from this toner density sensor 54 is input to the control unit 100, and based on this detection signal, the required toner replenishment amount is calculated.

[0046] Note that in a magnetic sensor, generally, the higher the toner density, the lower the sensor output value (voltage) [mV]. In the present embodiment, the toner density sensor 54 obtains, by calculation, a toner density detection value T, which is a value indicating the toner density in the developer based on the sensor output value (voltage) [mV]. Here, the toner density detection value T becomes a larger value as the toner density is higher.

[0047] FIG. 3 is a functional block diagram showing an example of the image forming apparatus of the present embodiment. The control unit 100 drives the toner replenishment motor 73 based on the detection signal from the toner density sensor 54 so that the mixing ratio of the carrier and the toner is within an appropriate range. Thereby, the control unit 100 controls the replenishment of the toner E from the hopper 72 to the developing device 5C.

[0048] Note that the toner replenishment motor 73 is a stepping motor, and its rotation amount is controlled by the number of drive pulses given from the control unit 100 to a stepping motor drive unit (not shown).

[0049] Further, the control unit 100 executes a toner recovery mode. The toner recovery mode is an operation mode for recovering the toner in the toner container 70. The toner container 70 includes the hopper 72 of the toner supply unit 7 and the supply chamber 58 and the agitation chamber 59 of the developing device 5. In the toner recovery mode, the control unit 100 develops the photosensitive drum 4 by the developing operation of the developing device 5 and transfers the toner to the photosensitive drum 4. Further, the control unit 100 removes the toner transferred to the photosensitive drum 4 by the recovery operation of the cleaner 8 without performing secondary transfer to the paper. In the toner recovery mode, the toner in the toner container 70 is recovered by performing the developing operation and the recovery operation.

[0050] Furthermore, the control unit 100 determines the amount of toner in the toner container 70 based on toner amount information that changes according to the amount of toner that can be supplied to the photosensitive drum 4 and the intermediate transfer belt 10. The toner amount information is, for example, the T / C ratio obtained from the detection signal of the toner density sensor 54.

[0051] The program causes the control unit 100 to execute a step of detecting toner amount information with the toner density sensor 54. Further, the program causes the control unit 100 to execute a step of determining whether the amount of toner that can be supplied to the photosensitive drum 4 has reached a predetermined amount for ending the toner recovery mode. The amount of toner that can be supplied to the photosensitive drum 4 is the amount of toner in the toner container 70. Then, when the program determines that the toner amount in the toner container 70 has reached the predetermined amount, the program causes the control unit 100 to execute a step of ending the toner recovery mode.

[0052] When the control unit 100 determines that the amount of toner in the toner container 70 has reached a predetermined amount for ending the toner recovery mode, the control unit 100 ends the toner recovery mode.

[0053] Alternatively, the program causes the control unit 100 to execute the step of detecting the toner amount information with the toner adhesion amount detection sensor 20. Further, the program causes the control unit 100 to execute the step of determining whether the amount of toner that can be supplied to the intermediate transfer belt 10 has reached a predetermined amount for ending the toner collection mode. The amount of toner that can be supplied to the intermediate transfer belt 10 is the amount of toner adhering to the intermediate transfer belt 10. Then, when the program determines that the amount of toner adhering to the intermediate transfer belt 10 has reached the predetermined amount, the program causes the control unit 100 to execute the step of ending the toner collection mode.

[0054] When the control unit 100 determines that the amount of toner adhering to the intermediate transfer belt 10 has reached a predetermined amount for ending the toner collection mode, the control unit 100 ends the toner collection mode.

[0055] Note that the image forming apparatus 1 includes a drive motor that drives other units, a solenoid that operates each unit, a polygon motor that scans the print head 6 with a laser beam LB, and the like. The control unit 100 controls these.

[0056] <Configuration example of the image forming apparatus and program according to the present embodiment> FIG. 4 is a flowchart showing an example of a control method of the image forming apparatus according to the present embodiment. Next, as a control method of the image forming apparatus, an example of a first embodiment of the toner collection mode will be described.

[0057] The toner collection mode is executed when the user selects the mode with the operation unit 101. The toner collection mode may be executed, for example, in a service mode that is not normally used by the user.

[0058] When the toner collection mode is selected with the operation unit 101 (step SA1), the control unit 100 starts the toner collection mode (step SA2).

[0059] In the toner collection mode, toner is not supplied from the toner bottle 71b to the toner container 70. Also, in the toner collection mode, paper (recording medium) is not fed or conveyed. Further, in the toner collection mode, secondary transfer and fixing of toner onto the paper are not performed. Therefore, the control unit 100 executes an inactivation process for functions not executed in the toner collection mode (step SA3).

[0060] In the inactivation process of step SA3, the control unit 100 closes the shutter 723a and stops the supply of toner to the hopper 72. Also, the control unit 100 stops the conveyance state detection function for jams and the like. Further, the control unit 100 stops the secondary transfer function, such as stopping the energization of the secondary transfer roller 16 and separating the secondary transfer roller 16. Also, the control unit 100 stops the fixing function, such as stopping the energization of a heater (not shown) of the fuser 17. Note that since the paper is not conveyed, the energization to the heater (not shown) of the fuser 17 may be continued by lowering the control temperature or reducing the input power.

[0061] In the toner collection mode, the control unit 100 develops each photosensitive drum 4 with a predetermined development pattern suitable for consuming the toner in the toner container 70 (step SA4). For example, the control unit 100 sets the potential of each photosensitive drum 4 to a potential at which development corresponding to a so-called solid (entire area) image can be performed. Then, the control unit 100 develops the photosensitive drum 4 by the development operation of the developing device 5. Note that the development pattern of the photosensitive drum 4 in the toner collection mode is related to the replenishable amount of toner. Therefore, it is not always necessary to develop the entire area of the photosensitive drum 4 corresponding to the maximum width of the paper. For example, when it is estimated that there is a sufficient amount of toner in the toner container 70, the photosensitive drum 4 in the range corresponding to the maximum width of the paper may be developed.

[0062] The control unit 100 repeats the recovery operation of removing and recovering the toner transferred to the photosensitive drum 4 in the developing operation with the cleaner 8 as it is. As a result, the toner in the toner container 70 gradually decreases. The control unit 100 determines whether the toner in the toner container 70 has reached a predetermined amount for ending the toner recovery mode based on the detection signal from the toner density sensor 54.

[0063] When the toner in the toner container 70 decreases, the T / C ratio obtained from the detection signal of the toner density sensor 54 increases. Therefore, the control unit 100 determines whether the T / C ratio is equal to or greater than a predetermined value (step SA5).

[0064] The control unit 100 determines that the toner in the toner container 70 has run out at the timing when the T / C ratio becomes equal to or greater than the predetermined value. Alternatively, the control unit 100 may determine that the toner in the toner container 70 has run out at the timing when a predetermined time has elapsed after the T / C ratio becomes equal to or greater than the predetermined value. When the control unit 100 determines that the toner in the toner container 70 has run out, it sets a toner recovery mode end flag (step SA6).

[0065] On the other hand, when the T / C ratio is lower than the predetermined value, the control unit 100 determines that the toner remains in the toner container 70. Then, the control unit 100 repeats the recovery operation of removing and recovering the toner transferred to the photosensitive drum 4 in the developing operation with the cleaner 8 as it is.

[0066] When the control unit 100 sets the toner recovery mode end flag, it stops the developing operation (step SA7). Even when it can be determined from the detection signal of the toner density sensor 54 that there is no toner in the toner container 70, there is still toner remaining on the waste toner recovery mechanism side including the cleaner 8. Therefore, after the control unit 100 sets the toner recovery mode end flag and stops the developing operation, it continues the recovery operation until a predetermined time elapses (step SA8).

[0067] When the control unit 100 continues the recovery operation for a predetermined time, it stops the recovery operation (step SA9) and ends the toner recovery mode (step SA10). The control unit 100 may notify the operation unit 101 of the end of the toner recovery mode by display or the like.

[0068] Note that the developing bias current may be detected as toner amount information that changes according to the amount of toner that can be supplied to the photoreceptor drum 4. The control unit 100 determines whether the toner in the toner container 70 has reached a predetermined amount for ending the toner recovery mode based on the detection signal from the developing bias current detection unit 102. When the toner in the toner container 70 decreases, the developing current value obtained from the detection signal of the developing bias current detection unit 102 becomes smaller. Therefore, the control unit 100 determines whether the developing current value is equal to or less than a predetermined value. The control unit 100 determines that the toner in the toner container 70 has run out at the timing when the developing current value becomes equal to or less than the predetermined value. Alternatively, the control unit 100 may determine that the toner in the toner container 70 has run out at the timing when a predetermined time has elapsed after the developing current value becomes equal to or less than the predetermined value. When the control unit 100 determines that the toner in the toner container 70 has run out, it sets a toner recovery mode end flag.

[0069] FIG. 5 is a flowchart showing another example of the control method of the image forming apparatus according to the present embodiment. Next, as an example of a second embodiment of the toner recovery mode, a control method of the image forming apparatus will be described.

[0070] When the toner recovery mode is selected by the operation unit 101 (step SB1), the control unit 100 starts the toner recovery mode (step SB2).

[0071] When the control unit 100 starts the toner recovery mode, it executes an inactivation process of functions not executed in the toner recovery mode (step SB3).

[0072] In the toner recovery mode, the control unit 100 develops each photosensitive drum 4 with a predetermined development pattern suitable for consuming the toner in the toner container 70 (step SB4). For example, the control unit 100 sets the potential of each photosensitive drum 4 to a potential at which development corresponding to a so-called solid (entire area) image can be performed. Then, the control unit 100 develops the photosensitive drum 4 by the developing operation of the developing device 5 to form a toner image on the photosensitive drum 4.

[0073] The control unit 100 primarily transfers the toner images formed on the photosensitive drums 4 of the respective imaging units 3Y, 3M, 3C, and 3K in the developing operation to the intermediate transfer belt 10.

[0074] The control unit 100 repeats a recovery operation of removing and recovering the toner primarily transferred to the intermediate transfer belt 10 in the primary transfer operation as it is with the cleaner 21. As a result, the toner in the toner container 70 gradually decreases. As a result, the amount of toner adhering to the intermediate transfer belt 10 decreases. Therefore, the control unit 100 detects the amount of toner adhering to the intermediate transfer belt 10 based on the detection signal from the toner adhesion amount detection sensor 20. The control unit 100 determines whether or not the toner adhering to the intermediate transfer belt 10 has become equal to or less than a predetermined amount for ending the toner recovery mode (step SB5).

[0075] The control unit 100 determines that the toner in the toner container 70 has run out at the timing when the toner adhering to the intermediate transfer belt 10 has become equal to or less than a predetermined amount. Alternatively, the control unit 100 may determine that the toner has run out at the timing when a predetermined time has elapsed after the toner adhering to the intermediate transfer belt 10 has become equal to or less than a predetermined amount. When the control unit 100 determines that the toner in the toner container 70 has run out, it sets a toner recovery mode end flag (step SB6).

[0076] On the other hand, when the toner adhering to the intermediate transfer belt 10 exceeds a predetermined amount, the control unit 100 determines that there is toner remaining in the toner storage unit 70. Then, the control unit 100 repeatedly performs a recovery operation of removing and recovering the toner primarily transferred to the intermediate transfer belt 10 by the primary transfer operation as it is with the cleaner 21.

[0077] When the control unit 100 sets the toner recovery mode end flag, it stops the developing operation and the primary transfer operation (step SB7). Further, after the control unit 100 sets the toner recovery mode end flag and stops the developing operation, it continues the recovery operation until a predetermined time elapses (step SB8).

[0078] When the control unit 100 continues the recovery operation for a predetermined time, it stops the recovery operation (step SB9) and ends the toner recovery mode (step SB10). The control unit 100 may notify the operation unit 101 by display or the like that the toner recovery mode has ended.

[0079] Note that the primary transfer current may be detected as toner amount information that changes according to the amount of toner that can be supplied to the intermediate transfer belt 10. The control unit 100 determines whether the toner has reached a predetermined amount for ending the toner recovery mode based on the detection signal from the primary transfer current detection unit 103. When the toner in the toner storage unit 70 decreases, the toner temporarily transferred to the intermediate transfer belt 10 decreases. When the toner temporarily transferred to the intermediate transfer belt 10 decreases, the primary transfer current value obtained from the detection signal of the primary transfer current detection unit 103 becomes smaller. Therefore, the control unit 100 determines whether the primary transfer current value is equal to or less than a predetermined value. The control unit 100 determines that the toner in the toner storage unit 70 has run out at the timing when the primary transfer current value becomes equal to or less than the predetermined value. Alternatively, the control unit 100 may determine that the toner in the toner storage unit 70 has run out at the timing when a further predetermined time has elapsed after the primary transfer current value becomes equal to or less than the predetermined value. When the control unit 100 determines that the toner in the toner storage unit 70 has run out, it sets the toner recovery mode end flag.

[0080] By the above toner collection mode, it is possible to collect the toner in the toner container 70 while directly or indirectly detecting the amount of toner in the toner container 70. Therefore, when reusing the image forming apparatus 1, it is not necessary to suck the toner remaining in the toner container 70 by an air pump or the like. Thus, toner can be collected efficiently without scattering toner around.

Explanation of Signs

[0081] 1 ··· Image forming apparatus, 1A ··· Automatic document feeder, 1B ··· Scanner, 1C ··· Printer unit, 1D ··· Paper feeding unit, 3Y, 3M, 3C, 3K ··· Imaging units, 4 ··· Photoconductor drum, 2 ··· Charging roller, 5 ··· Developing device, 6 ··· Print head, 7 ··· Toner supply unit, 8 ··· Cleaner, 9 ··· Cleaning roller, 10 ··· Intermediate transfer belt, 11 ··· Primary transfer roller, 12a, 12b, 12c ··· Paper feed cassettes, 13a, 13b, 13c ··· Paper feed rollers, 15 ··· Timing roller, 16 ··· Secondary transfer roller, 17 ··· Fuser, 18 ··· Separation member, 19 ··· Paper discharge tray, 20 ··· Toner adhesion amount detection sensor, 21 ··· Cleaner, 100 ··· Control unit, 101 ··· Operation unit, 102 ··· Developing bias current detection unit, 103 ··· Primary transfer current detection unit, 200 ··· Power supply unit

Claims

1. A housing portion for housing toner, An image carrier on which a toner image is formed, A developing unit that develops the image carrier, A removing unit that removes toner from the image carrier, A detection unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier, It includes a control unit that executes a toner recovery mode for removing toner from the image carrier without transferring the toner image to a recording medium, When the control unit determines based on the toner amount information detected by the detection unit that the amount of toner that can be supplied to the image carrier has reached a predetermined amount for ending the toner recovery mode, the control unit ends the toner recovery mode An image forming apparatus.

2. The detection unit includes a toner concentration sensor that detects the mixing ratio of the carrier contained in the developer, When the control unit determines that the ratio of toner to the developer has decreased and the mixing ratio of the carrier contained in the developer has become equal to or greater than a predetermined value, the control unit ends the toner recovery mode The image forming apparatus according to claim 1.

3. The image carrier includes a photoreceptor on which a toner image is developed by the developing unit and a transfer member to which the toner image is primarily transferred from the photoreceptor, The detection unit includes a toner adhesion amount detection sensor that detects the adhesion amount of the toner primarily transferred to the transfer member, When the control unit determines that the amount of toner primarily transferred to the transfer member has become equal to or less than a predetermined value for ending the toner recovery mode, the control unit ends the toner recovery mode The image forming apparatus according to claim 1.

4. The detection unit includes a developing bias current detection unit that detects a developing bias current, When the control unit determines that the developing bias current has become equal to or less than a predetermined value, the control unit ends the toner recovery mode The image forming apparatus according to claim 1.

5. The detection unit includes a primary transfer current detection unit that detects a primary transfer current, When the control unit determines that the primary transfer current has become equal to or less than a predetermined value, it ends the toner collection mode The image forming apparatus according to claim 1.

6. An image carrier on which a toner image is formed, A removal unit that removes toner from the image carrier, A detection unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier, A program executed by a control unit of an image forming apparatus in which a toner collection mode is executed to remove toner from the image carrier without transferring the toner image to a recording medium, A step of detecting toner amount information by the detection unit, Based on the toner amount information detected by the detection unit, when it is determined that the amount of toner that can be supplied to the image carrier has reached a predetermined amount for ending the toner collection mode, a step of ending the toner collection mode Causing the control unit to execute Program.

7. An image carrier on which a toner image is formed, A removal unit that removes toner from the image carrier, A detection unit that detects toner amount information that changes according to the amount of toner that can be supplied to the image carrier, A control method for an image forming apparatus in which a toner collection mode is executed to remove toner from the image carrier without transferring the toner image to a recording medium, A step of detecting toner amount information by the detection unit, Based on the toner amount information detected by the detection unit, when it is determined that the amount of toner that can be supplied to the image carrier has reached a predetermined amount for ending the toner collection mode, a step of ending the toner collection mode A control method for an image forming apparatus that executes.

Images