JP2017009668A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from being excessively supplied to a developing device.SOLUTION: A control unit, when toner is supplied to a developing device 48, drives a stepping motor 821A for the same time as the driving time of a supply gear 833 required for supplying toner to the developing device 48 in a case where an oscillation gear 834 is located at a supply position P1, drives the stepping motor 821A for the time calculated by adding the time required for moving oscillation gear 834 from an agitation position P2 to the supply position P1 to the driving time of the supply gear 833 required for supplying the toner to the developing device 48 in a case where the oscillation gear 834 is located at the agitation position P2, and drives the stepping motor 821A for the same time as the driving time of the supply gear 833 required for supplying the toner to the developing device 48 in a case where the position of the oscillation gear 834 is unknown.SELECTED DRAWING: Figure 11

Description

  The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a combination of these functions.

  2. Description of the Related Art Conventionally, an image forming apparatus includes a developing device that develops an electrostatic latent image formed on an image carrier with toner, a toner bottle that contains replenishing toner and is detachable and replaceable, and temporary replenishing toner. Some have a sub-hopper that stores them automatically. The sub hopper is provided with a screw member that conveys the toner in the sub hopper in order to replenish toner to the developing device, and the toner is supplied from the sub hopper to the developing device by rotating the screw member. .

  The sub hopper is provided with a toner amount detection sensor. When the toner amount detection sensor detects that the toner in the sub hopper is low, the operation panel or the like notifies the user that the toner has run out. . Thereafter, when the user replaces the toner bottle, the toner is supplied from the new toner bottle to the sub hopper.

  Conventionally, as such a toner amount detection sensor, there is an image forming apparatus using a sensor of a type that detects a toner amount in a sub hopper in conjunction with rotation of a screw member (see, for example, Patent Document 1). ).

JP 2011-175056 A

  However, in the image forming apparatus described in Patent Document 1, when the toner amount in the sub hopper is detected, the screw member also rotates at the same time, so that the toner is replenished excessively to the developing device. Therefore, there is a problem that the toner amount in the sub hopper cannot be detected at an arbitrary timing.

  An object of the present invention is to provide an image forming apparatus which has been improved by examining the current situation as described above.

  The first aspect of the present invention is a motor (821A), a first gear (833) for replenishing toner to the developing device (48), and a first position where the driving force by the motor can be transmitted to the first gear. A swing gear (834) swinging between (P1) and a second position (P2) where the driving force by the motor cannot be transmitted to the first gear, and the position of the swing gear are determined. An image forming apparatus including a position determination unit (control unit, S18, S39) and a replenishment control unit (control unit, FIGS. 11 and 12) that controls replenishment of toner to the developing device. When the position determination unit determines that the position of the swing gear is positioned at the first position when supplying toner to the developing device (YES in S19), the control unit Before it becomes necessary to supply toner to the developer When the motor is driven for the same time as the first gear drive time (necessary replenishment time), and the position determination unit determines that the position of the swing gear is located at the second position (in S13) YES), the time required for the rocking gear to move from the second position to the first position during the driving time of the first gear necessary for supplying toner to the developing device ( The motor is driven for the time added by (gear moving time), and when the position determining unit determines that the position of the rocking gear is unknown (NO in S19), the toner is supplied to the developer. The motor is driven for the same time as the drive time of the first gear necessary for the operation. Note that reference numerals, figure numbers, and capturing descriptions in parentheses show an example of a correspondence relationship with embodiments described later (the same applies hereinafter).

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the oscillating gear is rotated in the first direction (counterclockwise in FIG. 7) by the motor so that the oscillating gear is The oscillating gear is moved from the first position to the second position by rotating the oscillating gear in the second direction (clockwise in FIG. 8) by moving from the second position to the first position. It is configured to move to.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, when the position determining unit rotates the swing gear in the first direction by the motor for a predetermined time or more (YES in S17), When it is determined that the swing gear is located at the first position and the swing gear is rotated in the second direction by the motor for a certain period of time (YES in S38), the swing gear is It is determined to be located at the second position.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the position determination unit is turned on after the power of the image forming apparatus is turned off. Alternatively, when the motor is stopped while the swing gear is moving between the first position and the second position, it is determined that the position of the swing gear is unknown. It is.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the image forming apparatus further includes a toner amount detection unit (481) for detecting a toner amount in the developing unit, and the position determination unit. Is that when the toner amount detected by the toner amount detector increases (YES in S51), it is determined that the swing gear is located at the first position.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, when the replenishment control unit replenishes toner to the developing device, the position determination unit does not know the position of the swing gear. If it is determined that the motor is driven for the same time as the driving time of the first gear necessary for supplying toner to the developing device, the toner is started from the time when the driving of the motor is started. The drive of the motor is extended by the drive amount (unconnected time) of the motor until the toner amount detected by the amount detector increases (S53).

  According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, when the replenishment control unit replenishes the developer with toner, the position determination unit positions the swing gear. Is determined to be unknown, the motor is driven until at least the toner amount detected by the toner amount detection unit increases (FIG. 13).

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the second gear (837) and a sensor (830) whose output changes in conjunction with the rotation of the second gear. ), And the second position is a position at which the driving force of the motor can be transmitted to the second gear, and the position determination unit determines that the output of the sensor has changed (YES in S61). The swinging gear is determined to be located at the second position.

  A ninth aspect of the present invention is the image forming apparatus according to any one of the first to seventh aspects, further comprising a second gear (837), wherein the second position is driven by the motor by the second position. The position of the oscillating gear is determined by the position determination unit when the second gear is driven without driving the first gear (NO in S12). Is determined to be in the first position (YES in S33), the swinging gear is moved from the first position to the second position during the time for which the second gear should be driven (required stirring time). The motor is driven only for a time obtained by adding the time necessary for moving to (gear moving time).

  According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the sub hopper (82) temporarily stores the toner to be supplied to the developing device, the rotation of the second gear, and the inside of the sub hopper. A swing member (824) whose state changes according to the height of the toner surface, an empty sensor (830) that outputs an on signal or an off signal according to the state of the swing member, and the empty sensor And an empty determination unit (control unit) for determining whether or not the toner amount in the sub hopper is insufficient based on the output, and the output of the empty sensor has a sufficient amount of toner in the sub hopper. In the case where the amount of toner in the sub hopper is insufficient, the signal varies between the on signal and the off signal, and the The key determining unit determines whether or not the amount of toner in the sub hopper is insufficient based on the number of ON signals output from the empty sensor, and the replenishment control unit controls the first gear. When the position determination unit determines that the position of the swing gear is unknown (NO in S33) when driving the second gear without driving (NO in S12), the second gear The motor is driven for a time obtained by adding a time (gear moving time) required for the rocking gear to move from the first position to the second position to a time for driving the gear (necessary stirring time). The empty determination unit may be configured to start the drive of the motor by the replenishment control unit when the position determination unit determines that the position of the swing gear is unknown. When the ON signal from the empty sensor until the rocking gear is moved to the second position it is outputted is that ignores the ON signal.

  According to an eleventh aspect of the present invention, in the image forming apparatus according to the ninth or tenth aspect, a sub hopper (82) that temporarily stores toner to be supplied to the developing device, and rotation of the second gear. A swinging member (824) whose state changes according to the height of the toner surface in the sub hopper, an empty sensor (830) which outputs an on signal or an off signal according to the state of the swinging member, An empty determination unit (control unit) that determines whether or not the amount of toner in the sub hopper is insufficient based on the output of the empty sensor, and the output of the empty sensor is When the amount of toner is sufficient, the signal remains off, and when the amount of toner in the sub hopper is insufficient, the signal changes between the on signal and the off signal. The empty determination unit determines whether the amount of toner in the sub hopper is insufficient based on the number of ON signals output from the empty sensor, and the replenishment control unit includes the first supply control unit. When driving the second gear without driving the gear (NO in S12), if the position determination unit determines that the position of the swinging gear is unknown (NO in S33), The motor is operated only for a time obtained by adding a time (gear moving time) required for the rocking gear to move from the first position to the second position to a time for driving the second gear (necessary stirring time). When the on-signal is output from the empty sensor until the motor starts driving so that the swing gear moves to the second position. From that point, is that for driving the second by time period to drive the gear the motor.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the position determination unit is configured such that the swing gear moves between the first position and the second position. When the power of the image forming apparatus is turned off during the determination, it is determined that the position of the swing gear is unknown.

  According to the present invention, whether or not the driving force of the motor is transmitted to the first gear for replenishing toner to the developing device can be switched by the swing gear, so that the developing is performed when the motor is driven. It can be avoided that toner is unnecessarily supplied to the container.

  The replenishment control unit replenishes the developer with toner when the position determining unit determines that the position of the swing gear is located at the first position when replenishing toner to the developer. Since the motor is driven for the same time as the driving time of the first gear required for this, it is possible to prevent the toner from being excessively supplied to the developing device.

  The replenishment control unit replenishes the developer with toner when the position determination unit determines that the position of the swing gear is in the second position when replenishing toner to the developer. Since the motor is driven only for the time required for the swing gear to move from the second position to the first position to the driving time of the first gear required for this, a desired amount of toner is supplied to the developing device. Can be properly replenished.

  The replenishment control unit is necessary for replenishing the developer with toner when the position determination unit determines that the position of the swing gear is unknown when replenishing toner to the developer. Since the motor is driven for the same time as the driving time of the first gear, it is possible to prevent the toner from being excessively supplied to the developing device.

1 is an external perspective view illustrating a configuration of an image forming apparatus. 1 is a schematic configuration diagram illustrating an internal configuration of an image forming apparatus. FIG. 4 is a perspective view illustrating configurations of a toner bottle and a sub hopper. FIG. 2 is a schematic diagram illustrating a configuration of a toner bottle, a sub hopper, and a developing device. 4 is a cross-sectional view of a main part showing a positional relationship between a toner bottle and a sub hopper. FIG. It is a perspective view which shows the structure of a sub hopper. It is the schematic which shows the structure of a sub hopper drive mechanism. It is the schematic which shows the structure of a sub hopper drive mechanism. FIG. 6 is a diagram for describing toner empty detection control. FIG. 6 is a diagram for describing toner empty detection control. 6 is a part of a flowchart illustrating a first embodiment of toner replenishment control. 6 is a part of a flowchart illustrating a first embodiment of toner replenishment control. 7 is a flowchart illustrating a second embodiment of toner supply control. 12 is a flowchart illustrating a third embodiment of toner supply control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same parts or corresponding parts.

(1) Configuration of Image Forming Apparatus The configuration of the image forming apparatus 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is an external perspective view illustrating the configuration of the image forming apparatus 1, and FIG. 2 is a schematic configuration diagram illustrating the internal configuration of the image forming apparatus 1.

  As shown in FIGS. 1 and 2, the image forming apparatus 1 includes an image forming unit 2 that prints an image on a recording sheet, and an image reading unit 3 that reads an image from a document, and reads the image above the image forming unit 2. The structure which mounted the part 3 is provided. Further, the image forming apparatus 1 includes an operation panel 116 that performs various displays for the user and accepts an input operation by the user.

  The image reading unit 3 is a known unit that reads a document placed on a document glass plate by moving a scanner. The original image is color-separated into three colors of red (R), green (G), and blue (B), converted into an electrical signal by a CCD (CHARGE COUPLED DEVICE) image sensor, and R, G, B image data Is obtained. The image data of each color component obtained by the image reading unit 3 is subjected to various processes in the image control unit 11, and each reproduced color of cyan (C), magenta (M), yellow (Y), and black (K). Converted to image data.

  The image forming unit 2 includes an image forming device 4 that transfers a toner image based on image data onto a recording paper, a fixing device 5 that fixes the toner image transferred onto the recording paper by the image forming device 4, and an image for printing the image. And a paper discharge mechanism 7 for discharging the recording paper on which the toner image is fixed by the fixing device 5 and discharging the recording paper. The image reading unit 3 includes a scanner device 31 that reads an image from a document, and an automatic document feeder (ADF: AUTO DOCUMENT FEEDER) that is provided above the scanner device 31 and that transports the document to the scanner device 31 one by one. 32.

  The image forming device 4 located at the center in the image forming unit 2 plays a role of transferring a toner image formed on a photoconductor, which is an example of an image carrier, to a recording material P. A belt 42 and four image forming mechanisms 41 corresponding to the respective colors of yellow (Y), magenta (M), cyan (C) and black (K) are provided. In FIG. 2, for convenience of explanation, symbols Y, M, C, and K are attached to the image forming mechanisms 41 according to the reproduction colors.

  The intermediate transfer belt 42 is stretched between the driving roller 43 and the driven roller 44, and the driven roller 44 is urged to the left in FIG. 2 by a spring (not shown), thereby applying tension to the intermediate transfer belt 42. It has been. Then, the drive roller 43 rotates counterclockwise by power transmission from a transfer drive motor (not shown). A resin material such as polycarbonate, polyimide, or polyimide amide is used for the intermediate transfer belt 42. A transfer belt cleaner 421 is disposed on the outer peripheral side of the portion of the intermediate transfer belt 42 that is wound around the driven roller 44. The transfer belt cleaner 421 is for removing untransferred toner remaining on the intermediate transfer belt 42, and is in contact with the intermediate transfer belt 42.

  Below the intermediate transfer belt 42, image forming mechanisms 41 for each color of yellow (Y), magenta (M), cyan (C), and black (K) are arranged at predetermined intervals. A primary transfer roller 46 is disposed at a position facing the photosensitive drum 45 of each image forming mechanism 41 with the intermediate transfer belt 42 interposed therebetween. On the outer periphery of the photosensitive drum 45, a charger 47, a developing device 48, a primary transfer roller 46, and a photosensitive cleaner 49 are arranged in this order along the clockwise rotation direction in FIG.

  The photosensitive drum 45 is negatively charged and is configured to be driven to rotate clockwise in FIG. 2 by power transmission from a photosensitive motor (not shown). The charger 47 is of a roller charging type, and a voltage for charging the photosensitive member is applied to the charger 47 at a predetermined timing from a charging power source (not shown). The developing device 48 makes the electrostatic latent image formed on the photosensitive drum 45 visible by reversal development using toner having a negative polarity.

  The primary transfer roller 46 is located on the inner peripheral side of the intermediate transfer belt 42 and rotates in the counterclockwise direction of FIG. 2 as the intermediate transfer belt 42 rotates. A primary transfer nip portion, which is a primary transfer region, is formed between the intermediate transfer belt 42 and the primary transfer roller 46 (contact portion). The photoconductor cleaner 49 removes untransferred toner remaining on the photoconductor drum 45 and is in contact with the photoconductor drum 45. An exposure unit 50 is arranged below the four image forming mechanisms 41. The exposure unit 50 forms an electrostatic latent image on each photosensitive drum 45 with a laser beam based on the image data. The image data is subjected to correction for positional deviation correction, and then read out for each scanning line in synchronization with the supply of the recording paper, and serves as a drive signal for a light emitting diode provided in the exposure unit 50.

  A secondary transfer roller 51 is disposed on the outer peripheral side of the portion of the intermediate transfer belt 42 that is wound around the drive roller 43. The secondary transfer roller 51 is in contact with the intermediate transfer belt 42 and forms a secondary transfer nip portion where the intermediate transfer belt 42 and the secondary transfer roller 51 (contact portion) is a secondary transfer region. ing. The secondary transfer roller 51 rotates in the clockwise direction in FIG. 2 with the rotation of the intermediate transfer belt 42 or with the movement of the recording paper held and conveyed by the secondary transfer nip portion.

  The image forming device 4 charges the surface of the photosensitive drum 45 with the charger 47 and then forms an electrostatic latent image corresponding to the image data with the exposure unit 50. The toner from the developing device 48 is formed on the electrostatic latent image. To form a toner image on the surface of the photosensitive drum 45. The toner image formed on the surface of the photosensitive drum 45 is in the order of yellow, magenta, cyan, and black when the intermediate transfer belt 42 passes between the photosensitive drum 45 and the primary transfer roller 46 (primary transfer nip portion). Thus, primary transfer is performed on the intermediate transfer belt 42. Untransferred toner remaining on the photosensitive drum 45 is scraped off by the photosensitive cleaner 49 and removed from the photosensitive drum 45. Then, when the recording paper passes through the secondary transfer nip portion, the superimposed four color toner images are collectively transferred onto the recording paper. Untransferred toner remaining on the intermediate transfer belt 42 is scraped off by the transfer belt cleaner 421, removed from the intermediate transfer belt 42, and stored in a waste toner box (not shown).

  The fixing device 5 positioned above the secondary transfer roller 51 includes a heating roller 55 that is long in a direction orthogonal to the conveyance direction of the recording paper, and a pressure roller 56 that extends parallel to the heating roller 55. The pressure roller 56 is in contact with the heating roller 55, and a fixing nip portion that is a fixing region is formed between the heating roller 55 and the pressure roller 56 (contact portion). When the recording paper on which the unfixed toner image is placed after passing through the secondary transfer nip portion of the secondary transfer roller 51 passes through the fixing nip portion between the heating roller 55 and the pressure roller 56, The pressure roller 56 heats and presses the recording paper to fix the unfixed toner image on the recording paper.

  A paper feed mechanism 6 located below the image forming device 4 includes a plurality of stages (two stages in the embodiment) of paper feed cassettes 61 for storing recording paper, and a feeding roller for feeding out the recording paper in the paper feed cassette 61 one by one. 62, and a pair of registration rollers 63 for conveying the fed recording paper to the secondary transfer nip portion (secondary transfer region) at a predetermined timing. The paper discharge mechanism 7 includes a discharge roller 71 that discharges the recording paper on which the toner image is fixed by the fixing device 5 to the outside of the apparatus, and a paper discharge tray 72 that receives the discharged recording paper.

  Each paper feed cassette 61 is detachably disposed at the bottom of the image forming unit 2. The recording paper in each paper feed cassette 61 is sent out one by one from the top to the transport path 30 by the rotation of the corresponding feeding roller 62. The conveyance path 30 passes from each paper feed cassette 61 of the paper feed mechanism 6 to the nip portion between the registration rollers 63 and the secondary transfer nip portion (secondary transfer region) in the image forming device 4. It reaches the fixing nip. The conveyance path 30 extends from the fixing nip portion of the fixing device 5 to a discharge tray 72 on the upper surface of the image forming unit 2 via a pair of discharge rollers 71.

(2) Configuration of Toner Supply Path In the image forming apparatus 1, the toner bottle 81 is detachable in order to cause the developing device 48 to supply toner. As shown in FIG. 2, a bottle storage chamber 80 is provided above the intermediate transfer belt 42, and a toner bottle 81 that stores replenishment toner supplied to each developer 48 in the bottle storage chamber 80. Is detachably arranged. In FIG. 2, for convenience of explanation, the bottle storage chamber 80 and the toner bottle 81 are also denoted by symbols Y, M, C, and K according to the reproduction color. Details of the toner supply path from the toner bottle 81 to the developing device 48 will be described below with reference to FIGS.

  As shown in FIG. 4, a sub hopper 82 capable of storing a fixed amount of toner is provided corresponding to each developing device 48, and the toner is supplied from the sub hopper 82 to the developing device 48 via a joint 83. . As shown in FIG. 3, a toner bottle 81 is detachably provided above the sub hopper 82. When the remaining amount of toner in the sub hopper 82 decreases, toner is supplied from the toner bottle 81 to the sub hopper 82. When the toner in the toner bottle 81 runs out, it is replaced with a new toner bottle 81. In FIG. 3, for convenience of explanation, the toner bottle 81 and the sub hopper 82 are also provided with symbols Y, M, C, and K according to the reproduced colors.

  The toner bottle 81 includes a bottle portion 812 that stores toner, a cap portion 813 in which a supply port 813A is formed on the outer peripheral surface, and a shutter portion 815 that opens and closes the supply port 813A. The bottle part 812 and the cap part 813 are attached so as to be relatively rotatable. A knob 814 that rotates the toner bottle 81 is formed on the front side of the cap portion 813. Each cap portion 813 of the toner bottle 81 provided for each color is placed on the upper surface of a unit in which a sub-hopper 82 for each color is integrally formed.

  On the back side of the toner bottle 81, a bottle rotation mechanism 811 for rotating the bottle portion 812 is provided. The bottle rotation mechanism 811 includes a stepping motor 811A serving as a drive source, and transmits the rotational force of the stepping motor 811A to the toner bottle 81 via a gear mechanism (not shown). In FIG. 3, only two bottle rotation mechanisms 811 are shown, but the two-color toner bottle 81 is driven by one rotation drive mechanism, and is switched by a clutch mechanism (not shown). It has become. When the bottle portion 812 is rotated by the bottle rotation mechanism 811, the toner stored in the bottle portion 812 is guided to the supply port 813 A of the cap portion 813 by the spiral groove 817 formed on the inner peripheral surface of the bottle portion 812. It is burned. Then, the toner is dropped and supplied from the supply port 813A to the sub hopper 82.

  As shown in FIG. 4, the supply port 813 </ b> A of the cap portion 813 of the toner bottle 81 is positioned on the upper portion of the sub hopper 82. As shown in FIG. 5, a float member 824 for detecting the upper surface level of the toner is provided in the sub hopper 82 so as to be swingable about a shaft 824A. A cam 822 that rotates with the stirring shaft 825 is provided below the float member 824, and the float member 824 swings up and down by the rotation of the cam 822. In addition to the cam 822, the stirring shaft 825 is provided with a stirring plate 826 for leveling the upper surface of the toner.

  As shown in FIGS. 4 and 6, a shading plate 824B is attached to the shaft 824A in addition to the float member 824. When the float member 824 swings up and down, the shading plate 824B also moves up and down accordingly. Swing. A transmissive photosensor 830 is provided in the vicinity of the light shielding plate 824B, and the transmissive photosensor 830 causes the light shielding plate 824B to rise above a predetermined height (that is, the float member 824 exceeds the predetermined height). Can be detected).

  On the other hand, as shown in FIG. 4, the developing device 48 is provided with a toner concentration sensor 481, and when the toner concentration of the developing device 48 becomes low, the sub hopper 82 has a predetermined toner concentration. The replenishing roller 823 rotates to replenish the developer 48 with toner.

  The stirring shaft 825 and the replenishing roller 823 are driven by the sub hopper driving mechanism 821. Hereinafter, the sub hopper drive mechanism 821 will be described in detail with reference to FIGS. 7 and 8.

(3) Configuration of Sub Hopper Drive Mechanism As shown in FIGS. 7 and 8, the sub hopper drive mechanism 821 includes a stepping motor 821A serving as a drive source and a supply gear 833 for rotating a supply roller 823 of the sub hopper 82. And a stirring gear 837 for rotating the stirring shaft 825 of the sub hopper 82, a swinging gear 834, and a plurality of relay gears. Note that the stepping motor 821A can be rotated forward and backward, and FIG. 7 shows the state of the sub hopper drive mechanism 821 when the stepping motor 821A is driven to rotate forward. FIG. 8 shows the stepping motor 821A. The state of the sub hopper drive mechanism 821 when the reverse drive is performed is shown.

  The relay gear 831 rotates in conjunction with the rotation of the stepping motor 821A via another relay gear (not shown). The relay gear 832 is connected to the relay gear 831 and the swing gear 834. The swing gear 834 is supported so as to be swingable along an arcuate slide hole 835 formed along a circle centering on the rotation axis of the relay gear 832.

  As shown in FIG. 7, when the stepping motor 821A is driven to rotate forward, the relay gear 832 rotates in the clockwise direction. When the relay gear 832 rotates in the clockwise direction, in addition to the counterclockwise rotational force, the swing gear 834 moves along the sliding hole 835 toward the replenishment position P1 shown in FIG. The force to act acts. As a result, the swing gear 834 moves toward the replenishment position P1 while rotating counterclockwise, and finally rotates counterclockwise at the replenishment position P1 as shown in FIG. At the replenishment position P 1, the swing gear 834 is connected to the relay gear 832, the replenishment gear 833, and the agitation gear 837. Therefore, when the stepping motor 821A is driven forward, the swing gear 834 moves to the replenishment position P1, and the rotational force of the stepping motor 821A is transmitted to the replenishment gear 833 and the agitation gear 837. Both will rotate.

  As shown in FIG. 8, when the stepping motor 821A is driven in reverse, the relay gear 832 rotates counterclockwise. When the relay gear 832 rotates counterclockwise, the swing gear 834 moves along the sliding hole 835 toward the stirring position P2 shown in FIG. 8 in addition to the clockwise rotational force. The force to act acts. As a result, the swing gear 834 moves toward the stirring position P2 while rotating clockwise, and finally rotates clockwise at the stirring position P2 as shown in FIG. In the stirring position P2, the swing gear 834 is connected to the relay gear 832 and the relay gear 836. Since the relay gear 836 is connected to the stirring gear 837, when the stepping motor 821A is driven in the reverse direction, the swinging gear 834 moves to the stirring position P2, and the stirring gear 837 rotates.

  As described above, when the stepping motor 821A is driven to rotate forward, both the replenishment gear 833 and the agitation gear 837 rotate, so that the toner is replenished to the developing device 48 by the rotation of the replenishment roller 823 and at the same time the rotation of the agitation shaft 825. Thus, the toner in the sub hopper 82 is agitated. When the stepping motor 821A is driven in reverse, only the agitation gear 837 rotates, so that the toner in the sub hopper 82 is agitated by the rotation of the agitation shaft 825, but the toner is not replenished to the developing device 48.

(4) Toner Empty Detection Control Next, toner empty detection control executed by the control unit of the image forming apparatus 1 will be described with reference to FIGS. 9 and 10. Here, for the sake of convenience, description will be made assuming that there is no toner in the sub hopper 82.

  As shown in FIGS. 4, 9, and 10, a transmission type photosensor 830 is attached to the outer surface of the sub hopper 82, and the light shielding plate swings in conjunction with the float member 824 in the sub hopper 82. Depending on the position of 824B, an ON signal or an OFF signal is output from the transmissive photosensor 830.

  FIG. 9 shows a state where the float member 824 is pushed up to the highest position by the cam 822. In this state, the light shielding plate 824B is at the lowest position, and an OFF signal is output from the transmissive photosensor 830.

  When the stepping motor 821A of the sub hopper drive mechanism 821 described above is driven, the stirring shaft 825 and the replenishing roller 823 (or only the stirring shaft 825) rotate. When the stirring shaft 825 further rotates from the state of FIG. 9, the float member 824 is lowered at the same time, and the light shielding plate 824B is raised simultaneously (that is, the float member 824 and the light shielding plate 824B are centered on the shaft 824A). As clockwise). Then, light from the transmissive photosensor 830 is blocked by the light shielding plate 824B, and a signal output from the transmissive photosensor 830 changes from an OFF signal to an ON signal.

  FIG. 10 shows a state where the float member 824 is lowered to the lowest position. In this state, the light shielding plate 824B is at the highest position, and an ON signal is output from the transmissive photosensor 830.

  When the stirring shaft 825 further rotates from the state of FIG. 10, the float member 824 rises at the same time, and the light shielding plate 824B descends simultaneously (that is, the float member 824 and the light shielding plate 824B are centered on the shaft 824A). As counterclockwise). Then, light from the transmissive photosensor 830 is not blocked by the light shielding plate 824B, and a signal output from the transmissive photosensor 830 changes from an ON signal to an OFF signal.

  Note that when the sub hopper 82 is sufficiently filled with toner, the float member 824 stays on the surface of the toner and does not fall further therefrom. Therefore, even if the stirring shaft 825 rotates, the output of the transmissive photosensor 830 always remains an OFF signal.

  When an ON signal is output from the transmissive photosensor 830, the bottle rotation mechanism 811 is driven to rotate the bottle portion 812 of the toner bottle 81 for a predetermined time (for example, 10 seconds), and the toner is transferred from the toner bottle 81 into the sub hopper 82. Supply. At this time, the stepping motor 821A of the sub hopper driving mechanism 821 is also driven at the same time, and the stirring shaft 825 is also rotated. When the toner is supplied from the toner bottle 81 to the sub hopper 82, the height of the toner surface in the sub hopper 82 increases, and the float member 824 pushed up to the highest position by the cam 822 falls below the toner surface. Therefore, the output of the transmissive photosensor 830 remains an OFF signal.

  However, when the toner in the toner bottle 81 runs out, the toner is not replenished into the sub hopper 82 even if the bottle portion 812 is rotated. Therefore, in this case, the height of the toner surface in the sub hopper 82 does not rise, and the float member 824 pushed up to the highest position by the cam 822 is lowered to the original height again. The output of the photo sensor 830 once becomes an OFF signal and then becomes an ON signal again. As described above, when the ON signal is repeatedly output from the transmission type photosensor 830 even though the bottle unit 812 is rotated by the bottle rotation mechanism 811, it is determined that the toner in the toner bottle 81 has run out. This can be notified to the user.

  In this way, by monitoring the change in the signal output from the transmission type photosensor 830 while rotating the stirring shaft 825, the toner in the sub hopper 82 is insufficient or the toner in the toner bottle 81. Can be detected.

  On the other hand, the developing device 48 is provided with a toner concentration sensor 481 (see FIG. 4) for detecting the toner concentration in the two-component developer. When the toner concentration in the developing device 48 becomes low, the sub hopper driving mechanism 821 rotates the replenishing roller 823 of the sub hopper 82 so that the predetermined toner concentration is maintained, and the developing device 48 is supplied with the toner. Replenish. For example, when the target toner concentration is 5%, when the toner concentration becomes 4.5% or less, the supply roller 823 rotates and toner is supplied from the sub hopper 82 to the developing device 48. When the toner density reaches 5%, the replenishment roller 823 stops rotating.

  As described above, when the sub hopper drive mechanism 821 rotates the replenishing roller 823 of the sub hopper 82, the stirring shaft 825 also rotates at the same time. Therefore, while the toner is being supplied from the sub hopper 82 to the developing device 48, as described above, it is detected that the toner in the sub hopper 82 is insufficient or the toner in the toner bottle 81 is exhausted. Then, if necessary, toner is supplied from the toner bottle 81 to the sub hopper 82 and a notification that the toner in the toner bottle 81 is exhausted is issued.

(5) First Example of Toner Supply Control Next, a first example of toner supply control executed by the control unit of the image forming apparatus 1 will be described with reference to FIGS. 11 and 12.

  In step S11 of FIG. 11, a toner supply request (specifically, a toner supply request to only the developing device 48, a toner supply request to only the sub hopper 82, or a toner supply to both the developing device 48 and the sub hopper 82). When the request is generated, in step S12, the control unit determines whether it is necessary to supply toner to the developing device 48. When the toner supply to the developing device 48 is necessary (that is, the toner supply request to only the developing device 48 or the toner supply request to both the developing device 48 and the sub hopper 82), the processing is performed. The process proceeds to step S13. Otherwise (that is, in the case of a toner supply request to only the sub hopper 82), the process proceeds to step S31 in FIG.

  In step S13 of FIG. 11, the control unit determines whether the “gear state” is the “stirring position”. Here, the “gear state” is information that the control unit holds in the storage device as information indicating the current state of the swing gear 834. The “gear state” includes, for example, “replenishment position”, “stirring position”, “refilling movement”, and “stirring movement”. “Supply position” indicates that the swing gear 834 is located at the supply position P1 shown in FIG. The “stirring position” indicates that the swing gear 834 is positioned at the stirring position P2 shown in FIG. “During replenishment movement” indicates that the swing gear 834 is moving from the stirring position P2 toward the replenishment position P1. “During stirring movement” indicates that the swing gear 834 is moving from the replenishment position P1 toward the stirring position P2.

  In step S13, if the “gear state” is “stirring position”, the process proceeds to step S14, and if not, the process proceeds to step S19.

  By the way, when the toner is supplied to the developing device 48 in a state where the swing gear 834 is at the stirring position P2, the swing gear 834 is moved to the stirring position P2 after the stepping motor 821A starts to rotate forward. The replenishing gear 833 does not rotate during the period from when it moves to the replenishment position P1. That is, toner is not supplied to the developing device 48 during this period. Therefore, when the toner is replenished to the developing device 48 according to the time indicated in the toner replenishment request, that is, the time when the toner should be replenished to the developing device 48 (hereinafter referred to as a necessary replenishing time), It is necessary to drive the stepping motor 821A only for the time required for the swing gear 834 to move from the stirring position P2 to the replenishment position P1 (hereinafter referred to as gear movement time).

  Therefore, in step S14, the control unit calculates the time during which the stepping motor 821A should be driven forward (hereinafter referred to as the replenishment drive time) by adding the gear movement time to the necessary replenishment time. As the gear movement time, for example, a time (for example, 160 milliseconds) obtained in advance by actual measurement can be used. For example, when the necessary replenishment time is 600 milliseconds and the gear movement time is 160 milliseconds, the replenishment drive time is 760 milliseconds.

  In step S15, the control unit changes the “gear state” from “stirring position” to “replenishment moving”.

  In step S16, the control unit starts the replenishment drive for the replenishment drive time calculated in step S14 (that is, the forward rotation drive of the stepping motor 821A).

  In step S17, the control unit determines whether or not the time corresponding to the gear movement time has elapsed since the start of the replenishment drive in step S16. If the gear movement time has elapsed, the process proceeds to step S18.

  In step S18, the control unit changes the “gear state” from “during replenishment movement” to “replenishment position”.

  In step S19, the control unit determines whether the “gear state” is the “replenishment position”. If the “gear state” is “replenishment position”, the process proceeds to step S20. If not, the process proceeds to step S21.

  By the way, when the toner is replenished to the developing device 48 in a state where the swing gear 834 is located at the replenishment position P1, the replenishment gear 833 also rotates at the same time as the stepping motor 821A starts the forward rotation driving. Therefore, in step S20, the control unit starts the replenishment drive for the replenishment drive time using the replenishment drive time as it is without correcting the necessary replenishment time.

  On the other hand, when it is determined in step S19 that the “gear state” is not the “replenishment position”, in step S21, the control unit changes the “gear state” to the “replenishment position”. As described above, in step S20, the replenishment drive for the replenishment drive time is started as it is as the replenishment drive time without correcting the necessary replenishment time. For example, when the necessary replenishment time is 600 milliseconds, the replenishment drive time is also 600 milliseconds.

  As a case where the process of step S21 is performed, a case where the “gear position” is neither the “stirring position” nor the “replenishment position”, that is, the “gear position” is “refilling movement”, “stirring movement” or null It is a case that is a value. In these cases, since the exact position of the swing gear 834 cannot be grasped (that is, the position of the swing gear 834 is unknown), the swing gear 834 moves from the current position to the supply position P1. It is not possible to correctly calculate the time required for. Therefore, in this embodiment, when the position of the swing gear 834 is unknown as described above, replenishment control is performed assuming that the swing gear 834 is located at the refill position P1. Thus, when the position of the swing gear 834 is unknown, the replenishment drive for the replenishment drive time is performed as it is as the replenishment drive time without correcting the necessary replenishment time. There is no excessive supply of toner.

  As a result of the control described above, the time during which toner is actually supplied to the developing device 48 becomes shorter than the necessary supply time, and there is a possibility that a sufficient amount of toner will not be supplied to the developing device 48. However, in this case, since the toner supply request is generated again and the toner is supplied, the influence is small. On the other hand, when the toner is excessively supplied to the developing device 48, the toner remains in the developing device 48 because the influence remains for a long time until the excessive toner is consumed by the printing process. Priority should be given to preventing oversupply.

  As a typical example of the case where the position of the swing gear 834 is unknown, when the power of the image forming apparatus 1 is turned off and then turned on, or when the swing gear 834 is in the replenishment position P1 and the stirring position. For example, when the drive of the stepping motor 821A is interrupted because the door of the image forming apparatus 1 is opened or an error such as a jam occurs while moving between P2.

  In order to make it possible to accurately grasp the position of the swinging gear 834 even if the driving of the stepping motor 821A is interrupted while the swinging gear 834 is moving between the replenishment position P1 and the stirring position P2. When the swing gear 834 moves from the replenishment position P1 to the agitation position P2 (or from the agitation position P2 to the replenishment position P1), the number of drive pulses of the stepping motor 821A may be stored in the RAM as needed. Then, as long as the power of the image forming apparatus 1 is not turned off, the position of the swing gear 834 can be accurately grasped even if the driving of the stepping motor 821A is interrupted.

  In order to prevent the position of the swing gear 834 from becoming unknown even when the power of the image forming apparatus 1 is turned off, the “gear state” is changed when the “gear state” is changed (step S18 in FIG. 11 and the like). However, even in such a case, the power of the image forming apparatus 1 is turned off while the swing gear 834 is moving between the replenishment position P1 and the stirring position P2. When this happens, the position of the rocking gear 834 becomes unknown.

  In order to completely prevent the position of the oscillating gear 834 from becoming unknown, the current position of the oscillating gear 834 is detected by a sensor, or the stepping motor 821A after the oscillating gear 834 starts to move is detected. It is conceivable to store the number of drive pulses in the backup memory as needed, but there are problems that the configuration becomes complicated and the cost becomes high. Further, when the position of the swinging gear 834 becomes unknown, it is conceivable that the swinging gear 834 is temporarily moved to the stirring position P2 by driving the stepping motor 821A in the reverse direction for the gear moving time. If such control is performed every time the position of the moving gear 834 becomes unknown, there is a problem that power consumption increases.

  In step S <b> 22, the control unit determines whether the toner supply to the developing device 48 has been completed. Specifically, it is determined whether or not a time corresponding to the supply drive time has elapsed since the start of supply drive. When the toner supply to the developing device 48 is completed, the process proceeds to step S23.

  When the toner supply request generated in step S11 is a toner supply request to both the developing device 48 and the sub hopper 82, toner supply to the sub hopper 82 is performed simultaneously with toner supply to the developing device 48. . Even when the toner replenishment request generated in step S11 is a toner replenishment request to only the developing device 48, the toner in the sub hopper 82 is insufficient during the toner replenishment to the developing device 48. Is detected, toner supply to the sub hopper 82 is performed.

  In step S <b> 23, the control unit determines whether toner supply from the toner bottle 81 to the sub hopper 82 is completed. If the toner supply to the sub hopper 82 has been completed, the process proceeds to step S24. If not, the process proceeds to step S34 in FIG.

  In step S24, the control unit stops the replenishment drive. That is, the forward drive of the stepping motor 821A is stopped.

  In step S31 of FIG. 12, the control unit determines whether the “gear position” is the “stirring position”. If the “gear position” is the “stirring position”, the process proceeds to step S32. If not, the process proceeds to step S33.

  By the way, when the stirring shaft 825 is rotated in a state where the swing gear 834 is located at the stirring position P2, the stirring gear 837 also rotates at the same time as the stepping motor 821A starts the reverse rotation driving. Therefore, in step S32, the control unit corrects the necessary stirring time (that is, the time for rotating the stirring shaft 825 indicated in the toner replenishment request to the sub hopper 82) without correcting the stirring driving time ( That is, using the stepping motor 821A as the time for reverse driving, stirring driving for the stirring driving time (that is, reverse driving of the stepping motor 821A) is started.

  In step S33, the control unit determines whether the “gear position” is the “supply position”. If the “gear position” is the “supply position”, the process proceeds to step S34. If not (ie, the gear position is unknown), the process proceeds to step S35.

  By the way, when the stirring shaft 825 is rotated in a state where the swinging gear 834 is located at the replenishment position P1, the swinging gear 834 is moved from the replenishment position P1 to the stirring position after the stepping motor 821A starts reverse rotation driving. The stirring gear 837 does not rotate during the period until it moves to P2. That is, the stirring shaft 825 is not rotated during this period. Therefore, when the stirring shaft 825 is rotated according to the required stirring time indicated in the toner supply request, the time required for the swing gear 834 to move from the supply position P1 to the stirring position P2 during the required stirring time (ie, It is necessary to drive the stepping motor 821A for the time obtained by adding the gear movement time).

  Therefore, in step S34, the control unit calculates a time during which the stepping motor 821A should be driven in reverse (hereinafter referred to as agitation drive time) by adding the gear movement time to the required agitation time. In this embodiment, the time required for the swing gear 834 to move from the replenishment position P1 to the stirring position P2 is the same as the time required for the swing gear 834 to move from the stir position P2 to the refill position P1. However, if these times are different, different gear movement times may be used in step S14 in FIG. 11 and step S34 in FIG.

  On the other hand, if it is determined in step S33 that the “gear state” is not the “replenishment position” (that is, the position of the swing gear 834 is unknown), in step S35, the control unit determines that the “gear state” Change to “Replenishment position”. As described above, in step S34, the agitation drive time is calculated by adding the gear movement time to the required agitation time. Thereby, even when the position of the swing gear 834 is unknown, the stirring shaft 825 can be rotated at least for the necessary stirring time.

  In step S36, the control unit changes the “gear state” from “replenishment position” to “under stirring movement”.

  In step S37, the control unit starts stirring driving for the stirring driving time calculated in step S34.

  In step S38, the control unit determines whether or not a time corresponding to the gear movement time has elapsed since the start of the agitation drive in step S37. If the gear movement time has elapsed, the process proceeds to step S39.

  In step S39, the control unit changes the “gear state” from “stirring movement” to “stirring position”.

  In step S <b> 40, the control unit determines whether toner supply from the toner bottle 81 to the sub hopper 82 is completed. Specifically, it is determined whether or not the time corresponding to the stirring drive time has elapsed since the start of stirring drive. When the toner supply to the sub hopper 82 is completed, the process proceeds to step S41.

  In step S41, the control unit stops stirring drive. That is, the reverse drive of the stepping motor 821A is stopped.

(6) Second Example of Toner Supply Control Next, a second example of toner supply control executed by the control unit of the image forming apparatus 1 will be described with reference to FIG. Since the second embodiment is different from the first embodiment only in the processing after step S21 in FIG. 11, the description of the other processing is omitted. In FIG. 13, the same processes as those in FIG. 11 are denoted by the same reference numerals.

  In the case of NO in step S19 of FIG. 11 (that is, when the position of the rocking gear 834 is unknown), in the same manner as in the first embodiment, in step S21 of FIG. Then, in step S20, the replenishment drive for the replenishment drive time is started using the replenishment drive time as it is without correcting the necessary replenishment time.

  In step S51, the control unit determines whether the toner density in the developing device 48 detected by the toner density sensor 481 has increased. If the toner density in the developing device 48 has increased, the process proceeds to step S52.

  The increase in the toner density in the developing device 48 means that the toner is supplied from the sub hopper 82 to the developing device 48. The fact that the toner is supplied from the sub hopper 82 to the developing device 48 means that the replenishing gear 833 and the replenishing roller 823 are rotated, that is, the swinging gear 834 is located at the replenishing position P1. That is, by confirming that the toner density in the developing device 48 has increased, it is possible to confirm that the swing gear 834 is located at the replenishment position P1.

  In step S52, the control unit calculates the elapsed time after starting the replenishment drive in step S20 as the unconnected time. That is, the unconnected time is the time from when the replenishment driving is started until it is confirmed that the swing gear 834 is located at the replenishment position P1 due to the increase in toner density. It can be considered that it is the time from the start of driving until the swing gear 834 is actually connected to the replenishing gear 833.

  In step S53, the control unit extends the replenishment drive time by the unconnected time and continues the replenishment drive. For example, if the replenishment drive time set in step S20 (ie, the required replenishment time) is 600 milliseconds and the unconnected time is 80 milliseconds, the extended replenishment drive time is 680 milliseconds.

  The processing following step S53 (the processing after step S22) is the same as in the first embodiment.

  As described above, according to the second embodiment, when the position of the swing gear 834 is unknown, it is assumed that the swing gear 834 is positioned at the supply position P1, and the replenishment drive is started. When it is confirmed that the toner density in the developing device 48 has increased, the replenishment drive time is extended by the elapsed time up to that point. Therefore, the toner can be reliably supplied to the developing device 48 for at least the necessary supply time.

  Further, according to the second embodiment, for example, when the necessary replenishment time is shorter than the gear movement time (for example, when the necessary replenishment time is 100 milliseconds and the gear movement time is 160 milliseconds), However, the replenishment drive is continued until it is confirmed that the toner density in the developing device 48 has increased (that is, until it is confirmed that the swing gear 834 is located at the replenishment position P1). Therefore, it is possible to avoid the supply drive from being stopped before the swing gear 834 reaches the supply position P1.

  Here, the replenishment drive time is extended by the time from the start of the replenishment drive until the toner density in the developing device 48 increases. However, the present invention is not limited to this. The replenishment drive may be extended by the drive amount (for example, the rotation angle or the number of drive pulses) of the stepping motor 821A until the toner density in 48 increases.

  Although the toner density sensor 481 is used here, the present invention is not limited to this, and any sensor that can detect that the amount of toner in the developing device 48 has increased or toner has been supplied to the developing device 48. May be used.

(7) Third Example of Toner Supply Control Next, a third example of toner supply control executed by the control unit of the image forming apparatus 1 will be described with reference to FIG. Since the third embodiment is different from the first embodiment only in the processing after step S35 in FIG. 12, the description of the other processing is omitted. In FIG. 14, the same processes as those in FIG. 12 are denoted by the same reference numerals.

  In the case of NO in step S33 of FIG. 12 (that is, when the position of the rocking gear 834 is unknown), in the same manner as in the first embodiment, in step S35 of FIG. Is changed to the “replenishment position”, and then in step S34, the agitation drive time is calculated by adding the gear moving time to the required agitation time. In step S36, the “gear state” is changed from the “replenishment position”. In step S37, the agitation drive for the agitation drive time calculated in step S34 is started.

  In step S61, the control unit determines whether the output signal of the transmissive photosensor 830 has changed (that is, whether the output signal has changed from an ON signal to an OFF signal or from an OFF signal to an ON signal). If the output signal of the transmissive photosensor 830 has changed, the process proceeds to step S62.

  The change in the output signal of the transmissive photosensor 830 means that the light shielding plate 824B and the float member 824 are swung. The fact that the float member 824 is swung means that the stirring gear 837 and the stirring shaft 825 are rotated, that is, the swinging gear 834 is located at the stirring position P2. That is, by confirming that the output signal of the transmissive photosensor 830 has changed, it can be confirmed that the swing gear 834 is located at the stirring position P2.

  In step S62, the control unit calculates an elapsed time after starting the agitation drive in step S37 as an unconnected time. That is, the unconnected time is the time from the start of stirring driving until it is confirmed that the rocking gear 834 is positioned at the stirring position P2 by the change in the output signal of the transmission type photosensor 830. Thus, this can be regarded as the time from the start of the agitation drive until the swing gear 834 is actually connected to the agitation gear 837.

  In step S63, the control unit shortens the stirring drive time by the difference between the gear moving time and the unconnected time, and continues the stirring drive. For example, if the necessary stirring time is 600 milliseconds, the gear moving time is 160 milliseconds, and the unconnected time is 40 milliseconds, the stirring driving time set in step S37 is 760 milliseconds. The replenishment drive time after shortening in step S63 is 640 milliseconds (that is, the sum of the necessary stirring time and the unconnected time).

  The processing following step S63 (the processing after step S39) is the same as in the first embodiment.

  As described above, according to the third embodiment, when the position of the swing gear 834 is unknown, it is temporarily regarded that the swing gear 834 is located at the replenishment position P1, and the stirring drive is started. When it is confirmed that the output signal of the transmissive photosensor 830 has changed, the agitation drive time is reduced in consideration of the elapsed time up to that point. As a result, from the time when it is confirmed that the output signal of the transmission type photosensor 830 has changed (that is, when it is confirmed that the rocking gear 834 is located at the stirring position P2), only the necessary stirring time. Then, stirring drive is performed. Therefore, it is possible to avoid the stirring drive being performed unnecessarily long.

  Here, the agitation drive time is shortened according to the time from when the agitation drive is started to when the output signal of the transmission type photosensor 830 is changed. The agitation drive may be shortened according to the drive amount (for example, the rotation angle and the number of drive pulses) of the stepping motor 821A until the output signal of the transmissive photosensor 830 changes.

  Although the output signal of the transmissive photosensor 830 is used here, the present invention is not limited to this, and the output of any sensor that can detect that the float member 824 has swung or the stirring shaft 825 has rotated. A signal may be used.

  As described above, in toner empty detection control, an ON signal is repeatedly output (for example, three times) from the transmissive photosensor 830 even though the bottle portion 812 is rotated by the bottle rotation mechanism 811. Is determined that the toner in the toner bottle 81 has run out. Therefore, since it is preferable to rotate the bottle part 812 and the stirring shaft 825 at the same time, when the swing gear 834 is located at the replenishment position P1 or when the position of the swing gear 834 is unknown, the swing gear The bottle portion 812 is rotated after 834 reaches the stirring position P2.

  By the way, at the time of step S61, the “gear state” is “being moved by stirring”, so that the sub-hopper 82 is not yet supplied with toner. In such a state, even if the signal of the transmissive photosensor 830 changes from the OFF signal to the ON signal, this does not mean that the toner in the toner bottle 81 has run out. Therefore, when the signal of the transmissive photosensor 830 changes from the OFF signal to the ON signal in step S61, this ON signal (that is, the first ON signal) is ignored in the toner empty detection control. preferable.

(8) Modifications The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, a printer has been described as an example of the image forming apparatus. However, the image forming apparatus is not limited thereto, and may be a copier, a facsimile, or a complex machine having these functions in combination. In addition, the configuration of each unit is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 82 Sub hopper 481 Toner density sensor 821 Sub hopper drive mechanism 821A Stepping motor 822 Cam 823 Supply roller 824 Float member 824A Shaft 824B Shading plate 825 Stirring shaft 826 Stirring plate 830 Transmission type photo sensor 831 Relay gear 832 Relay gear 833 Supply gear 834 Oscillating gear 835 Sliding hole 836 Relay gear 837 Stirring gear

Claims (12)

A motor,
A first gear for supplying toner to the developing device;
A swing gear that swings between a first position where the driving force by the motor can be transmitted to the first gear and a second position where the driving force by the motor cannot be transmitted to the first gear;
A position determination unit for determining the position of the rocking gear;
A replenishment control unit that controls replenishment of toner to the developing unit;
The replenishment control unit, when replenishing toner to the developer,
When the position determination unit determines that the position of the swing gear is positioned at the first position, the driving time of the first gear necessary for supplying toner to the developing device; Drive the motor for the same time,
If the position determination unit determines that the position of the swing gear is in the second position, the driving time of the first gear necessary for supplying toner to the developer is reached. Driving the motor for a time that is added to the time required for the swing gear to move from the second position to the first position;
When the position determination unit determines that the position of the swing gear is unknown, the motor is operated for the same time as the driving time of the first gear necessary for supplying toner to the developer. An image forming apparatus to be driven.   The rocking gear is moved from the second position to the first position by rotating the rocking gear in the first direction by the motor, and the rocking gear is rotated in the second direction by the motor. The image forming apparatus according to claim 1, wherein the swing gear is configured to move from the first position to the second position. The position determination unit
When the swing gear is rotated in the first direction by the motor for a predetermined time or more, it is determined that the swing gear is located at the first position;
The image forming apparatus according to claim 2, wherein the swinging gear is determined to be located at the second position when the swinging gear is rotated in the second direction by the motor for a predetermined time or more.   The position determination unit is turned on after the power of the image forming apparatus is turned off, or while the swinging gear is moving between the first position and the second position. The image forming apparatus according to claim 1, wherein when the motor is stopped, the position of the swing gear is determined to be unknown. A toner amount detector for detecting the amount of toner in the developing unit;
The position determination unit determines that the swing gear is located at the first position when the toner amount detected by the toner amount detection unit increases. The image forming apparatus described in the item.   The replenishment control unit is configured to replenish toner to the developer when the position determination unit determines that the position of the swing gear is unknown when replenishing toner to the developer. The motor is driven for the same time as the required driving time of the first gear, and the motor of the motor from the time when the driving of the motor is started to the time when the amount of toner detected by the toner amount detecting unit increases. The image forming apparatus according to claim 5, wherein the driving of the motor is extended by a driving amount.   The replenishment control unit detects at least the toner amount detection unit when the position determination unit determines that the position of the swing gear is unknown when replenishing toner to the developer. The image forming apparatus according to claim 5, wherein the motor is driven until a toner amount increases. The second gear,
A sensor whose output changes in conjunction with the rotation of the second gear;
The second position is a position where the driving force by the motor can be transmitted to the second gear,
The image forming apparatus according to claim 1, wherein the position determination unit determines that the swing gear is positioned at the second position when an output of the sensor changes. . A second gear,
The second position is a position where the driving force by the motor can be transmitted to the second gear,
The replenishment control unit, when driving the second gear without driving the first gear, when the position determination unit determines that the position of the swing gear is in the first position. The motor is driven for a time obtained by adding a time required for the rocking gear to move from the first position to the second position to a time for driving the second gear. The image forming apparatus according to any one of the above. A sub hopper for temporarily storing toner to be supplied to the developing unit;
A swing member whose state changes according to the rotation of the second gear and the height of the toner surface in the sub hopper;
An empty sensor that outputs an on signal or an off signal according to the state of the swing member;
An empty determination unit that determines whether the amount of toner in the sub hopper is insufficient based on the output of the empty sensor;
The output of the empty sensor remains an off signal when the amount of toner in the sub hopper is sufficient, and between the on signal and the off signal when the amount of toner in the sub hopper is insufficient. Fluctuate,
The empty determination unit determines whether the amount of toner in the sub hopper is insufficient based on the number of ON signals output from the empty sensor,
When the position determination unit determines that the position of the swing gear is unknown when driving the second gear without driving the first gear, the replenishment control unit Driving the motor for a time obtained by adding a time required for the swing gear to move from the first position to the second position to a time to drive two gears;
When the position determining unit determines that the position of the swinging gear is unknown, the empty determining unit determines that the swinging gear is moved to the second position after the motor is started to be driven by the replenishment control unit. The image forming apparatus according to claim 9, wherein when an ON signal is output from the empty sensor before moving to a position, the ON signal is ignored. A sub hopper for temporarily storing toner to be supplied to the developing unit;
A swing member whose state changes according to the rotation of the second gear and the height of the toner surface in the sub hopper;
An empty sensor that outputs an on signal or an off signal according to the state of the swing member;
An empty determination unit that determines whether the amount of toner in the sub hopper is insufficient based on the output of the empty sensor;
The output of the empty sensor remains an off signal when the amount of toner in the sub hopper is sufficient, and between the on signal and the off signal when the amount of toner in the sub hopper is insufficient. Fluctuate,
The empty determination unit determines whether the amount of toner in the sub hopper is insufficient based on the number of ON signals output from the empty sensor,
When the position determination unit determines that the position of the swing gear is unknown when driving the second gear without driving the first gear, the replenishment control unit The driving of the motor is started so as to drive the motor only for a time obtained by adding the time necessary for the swing gear to move from the first position to the second position to the time to drive the two gears. Thereafter, when an ON signal is output from the empty sensor until the swing gear moves to the second position, the motor is driven for the time to drive the second gear from that point. The image forming apparatus according to claim 9, wherein the image forming apparatus is driven.   The position determination unit is configured to detect the position of the swing gear when the power of the image forming apparatus is turned off while the swing gear is moving between the first position and the second position. The image forming apparatus according to claim 1, wherein the image forming apparatus determines that is unknown.

Images