JP5315272B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus including an image carrier and a developing device.

  An electrophotographic image forming apparatus reads an original image or irradiates light on the peripheral surface of an image carrier (photosensitive drum) with light based on image information transmitted from an external device such as a computer to form an electrostatic latent image. A toner (developer) is supplied to the electrostatic latent image from a developing device to form (develop) the toner image, and then the toner image is transferred to a sheet. The paper after the transfer process is subjected to a toner image fixing process and then discharged to the outside. Further, the toner is replenished to the developing device by rotating the toner conveying member from the toner container by the amount reduced by the development.

  In such an image forming apparatus, by increasing the rotation accuracy of the toner conveying member, the toner container is prevented from being oversupplied or oversupplied to the developing device, and the toner replenishment amount is stabilized to improve the image quality. be able to. Therefore, a technique for adjusting the toner replenishment amount by controlling the rotation speed and rotation time of the toner conveying member has been proposed.

  For example, Patent Document 1 discloses that the number of rotations and the rotation time of a toner conveying screw are controlled from the amount of toner consumed in the developing device. Patent Document 2 discloses that the rotation time and the rotation speed of the toner conveying member are controlled based on the number of print pixels.

  Further, in Patent Document 3, a model identification unit that can be detected by an optical sensor is formed on a flange portion surrounding a rotation shaft in a rotation drive transmission gear provided on the rotation shaft of a stirring member, and a detection signal from the optical sensor is used as a detection signal. On the basis of this, it is disclosed that the number of rotations of the stirring member is counted and the toner replenishment amount is quantitatively integrated. Patent Document 4 discloses that a circular stop member provided with a slit is formed integrally with a conveying member, and the rotation of the circular stop member is detected by a photo sensor.

JP 2003-316144 A JP 2006-145766 A JP 2005-99434 A JP 2005-3796 A

  However, Patent Documents 1 and 2 do not disclose or suggest that the rotation amount of the rotation shaft is detected using an optical sensor. In Patent Document 2, a pulse corresponding to the pixel number signal is input to the pulse motor to adjust the rotation speed of the pulse motor. However, the pulse motor is expensive.

  In addition, for example, when an inexpensive brush motor is used, fluctuations in the number of revolutions may occur due to the performance of the motor itself such as fluctuations in the starting performance of the revolutions during operation of the motor, fluctuations in brake performance, and torque fluctuations. There is. If the fluctuation of the rotational speed is simply adjusted by the rotation time or the like, the toner replenishment amount may fluctuate and image defects such as fog may occur.

  On the other hand, in Patent Document 3, the light from the optical sensor is emitted to the flange portion of the rotational drive transmission gear. However, when the shaft variation of the gear, the positional deviation between the flange portion and the optical sensor, or the like occurs, There is a possibility that the number of rotations of the stirring member cannot be sufficiently detected.

  Moreover, in patent document 4, since the circular stop member and the transmission part of the rotational drive from the drive motor in a conveyance member are not integrated, the arrangement | positioning shift | offset | difference of the rotating shaft of a conveyance member, a rotation shaft, and a circular stop member There is a possibility that the amount of rotation of the conveying member cannot be stably detected due to the influence of the positional deviation. Further, in Patent Document 4, when the slit of the circular stop member is detected by the photosensor, the rotation of the conveying member is stopped. However, as described above, for example, when a brush motor is used, due to fluctuations in motor performance, There is a possibility that the rotation amount of the conveying member cannot be detected appropriately.

  SUMMARY An advantage of some aspects of the invention is that it provides a developer supply device capable of stabilizing the amount of developer supplied to the developing device and an image forming apparatus including the developer supply device.

  In order to solve the above-described problems, the present invention provides a container in which a developer for replenishing the developing device is accommodated, and a conveying member that supplies the developer in the container while rotating the developer. A developer replenishing device having a drive transmission gear portion disposed at one axial end portion of the rotation shaft of the conveying member and transmitting the rotational drive from the driving means; and integrally formed with the drive transmission gear portion. A flange portion that protrudes along a vertical direction with respect to the axial direction and has a substantially circular shape centered on the rotation axis, and has a slit arranged concentrically around the rotation axis. A drive transmission member having a light emitting portion that is disposed across a peripheral edge portion of the flange portion and capable of emitting light to the slit; and a light receiving portion capable of receiving light emitted from the light emitting portion. , Pulse by the slit Detection means for detecting a rotation amount of the conveying member to read the form, it is characterized in that is provided.

  According to the present invention, in the developer replenishing device having the above-described configuration, a support portion that is detachable from the storage container and forms a part of an outer wall of the storage container is provided, and the detection unit is attached to the support portion. It is characterized by that.

  According to the present invention, in the developer replenishing device configured as described above, the slit is formed by a gap between protruding portions that protrude substantially perpendicularly from a peripheral edge portion of the flange portion.

  According to the present invention, in the developer replenishing device having the above-described configuration, the number of pulses generated by the rotation of the conveying member is counted based on the detection result of the detecting unit, and the conveying member is counted according to the counted number of pulses. It is characterized by adjusting the amount of rotation at the next rotation.

  According to the present invention, in the developer replenishing device having the above-described configuration, when it is detected that the transport member has overrun the target pulse number, the number of pulses increased from the target pulse number is reduced. It is characterized in that the amount of rotation at the next rotation of the conveying member is adjusted.

  Further, the present invention is an image forming apparatus provided with the developer supply device having the above-described configuration.

  According to the first configuration of the present invention, the drive transmission gear portion to which the rotational drive from the driving means is transmitted to the one axial end portion of the rotation shaft of the transport member, and the drive transmission gear portion are formed integrally. A drive transmission member having a flange portion that protrudes along the vertical direction and is formed in a substantially circular shape centering on the rotation axis and having a slit concentrically arranged around the rotation axis And having a light emitting part capable of emitting light to the slit and a light receiving part capable of receiving the light emitted from the light emitting part, and having a pulse waveform by the slit By providing a detecting means for detecting the rotation amount of the conveying member by reading the above, it is not necessary to detect the rotation amount of the drive transmission member via a rotating shaft or the like.

  Thereby, since the rotation amount of the conveying member can be detected without being affected by the displacement of the rotation shaft or the positional deviation between the rotation shaft and the flange portion, the rotation amount of the conveying member can be detected stably. Therefore, the developer replenishment amount to the developing device can be stabilized.

  Further, according to the second configuration of the present invention, in the developer supply device of the first configuration, the support unit that is detachable from the storage container and forms a part of the outer wall of the storage container is provided, and the detection unit is provided. By attaching the support part to the receiving container, the flange part and the detection means are positioned by simply attaching the support part to the storage container. Therefore, it is possible to prevent the flange part and the detection means from being displaced during assembly. . Thereby, the rotation amount of the conveying member can be detected more stably. Further, even when a positional deviation or the like occurs, it is effective because the positional relationship between the two can be easily corrected by detaching the support portion from the storage container.

  According to the third configuration of the present invention, in the developer replenishing device having the first or second configuration, the slit is formed from a gap between the protruding portions that protrude substantially perpendicularly from the peripheral edge portion of the flange portion. This facilitates detection by the detecting means. In addition, when the detection means is detachably attached to the support portion, the slit can be detected only by projecting the light emitting portion and the light receiving portion along the axial direction from the support portion. Thereby, a detection means can be attached without difficulty and the detection of a detection means can be stabilized.

  According to the fourth configuration of the present invention, in the developer supply device having any one of the first to third configurations, the number of pulses generated by the rotation of the conveying member is calculated based on the detection result of the detection unit. Counting and adjusting the amount of rotation at the next rotation of the conveying member according to the counted number of pulses, even when using a drive means such as a brush motor that tends to vary in the number of rotations. Since the amount can be adjusted appropriately, the amount of developer replenishment to the developing device can be stabilized.

  According to the fifth configuration of the present invention, in the developer supply device of the fourth configuration, when it is detected that the conveying member has overrun the target pulse number, the target pulse number is exceeded. By adjusting the amount of rotation at the next rotation of the conveying member by reducing the increased number of pulses, the developer replenishment amount can be adjusted to an appropriate amount even if fluctuations occur in the start-up performance and braking performance of the driving means. Therefore, it is effective.

  According to the sixth configuration of the present invention, the developer replenishment amount to the developing device is stabilized by using the image forming apparatus including the developer replenishing device having any one of the first to fifth configurations. Image quality can be improved.

1 is a schematic configuration diagram of an image forming apparatus including a developer supply device according to an embodiment of the present invention. Schematic side sectional view showing a configuration of a developing device in which developer is replenished from the developer replenishing device of the present embodiment Schematic side cross-sectional view showing the configuration around the conveying member in the developer supply device of this embodiment Schematic perspective view showing the configuration around the drive transmission member and the optical sensor Schematic perspective view showing a drive transmission member The figure which shows the state where the slit overruns FIGS. 7A and 7B are diagrams showing a modification of the drive transmission member together with the optical sensor, in which FIG. 7A is a front view, and FIG. 7B is a view of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus equipped with the developing device of the present invention. Here, a tandem color image forming apparatus is shown. In the main body of the color printer 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  The image forming portions Pa to Pd are provided with photosensitive drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors, and are further driven by a driving unit (not shown). The intermediate transfer belt 8 that rotates clockwise is provided adjacent to the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1a to 1d are sequentially primary-transferred and superimposed on the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1a to 1d, and then the secondary transfer roller. 9 is secondarily transferred onto a transfer paper P as an example of a recording medium, and further fixed on the transfer paper P in the fixing unit 13 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d counterclockwise in FIG.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the apparatus, and drives a secondary transfer roller 9 and an intermediate transfer belt 8 described later via a paper feed roller 12a and a registration roller pair 12b. It is conveyed to the nip portion with the roller 11. A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt having no seam is mainly used. A blade-like belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed downstream of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure device 5 for exposing the toner, the developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning parts 7a, 7b, 7c and 7d are provided.

  When image data is input from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated according to the image data by the exposure device 5. The electrostatic latent images corresponding to the image data are formed on the respective photosensitive drums 1a to 1d. Each of the developing devices 3a to 3d is filled with a predetermined amount of a two-component developer containing toner of each color of cyan, magenta, yellow, and black. If the ratio of the toner in the two-component developer filled in each of the developing devices 3a to 3d is less than the specified value due to the formation of a toner image described later, the toner containers (developer supply devices) 4a to 4d Developers (toner and carrier) are supplied to each of the developing devices 3a to 3d. The toner in the developer is supplied onto the photosensitive drums 1a to 1d by the developing devices 3a to 3d and electrostatically adheres to the electrostatic latent image formed by the exposure from the exposure device 5. A toner image is formed.

  Then, by applying a predetermined transfer voltage to the primary transfer rollers 6 a to 6 d, yellow, cyan, magenta, and black toner images on the photosensitive drums 1 a to 1 d are primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning units 7a to 7d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched between an upstream conveyance roller 10 and a downstream drive roller 11, and the intermediate transfer belt 8 rotates clockwise as the drive roller 11 is rotated by a drive motor (not shown). When the rotation starts, the transfer paper P is conveyed from the registration roller 12b to the nip portion (secondary transfer nip portion) between the drive roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing. The full color image on the intermediate transfer belt 8 is transferred onto the transfer paper P. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressurized by the fixing roller pair 13a, and the toner image is fixed on the surface of the transfer paper P, so that a predetermined full color image is formed. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching portion 14 that branches in a plurality of directions. When an image is formed only on one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller 15.

  On the other hand, when forming images on both sides of the transfer paper P, the transfer paper P that has passed through the fixing unit 13 is once transported in the direction of the discharge roller 15, and the discharge roller after the rear end of the transfer paper P has passed through the branching unit 14. 15 is rotated in the reverse direction and the conveyance direction of the branching portion 14 is switched, so that the paper is distributed from the rear end of the transfer paper P to the paper conveyance path 18 and re-conveyed to the secondary transfer nip portion with the image surface reversed. . Then, after the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the surface of the transfer paper P where the image is not formed and conveyed to the fixing unit 13 and the toner image is fixed. , And discharged to the discharge tray 17.

  FIG. 2 is a schematic side cross-sectional view showing the configuration of the developing device in which the developer is replenished from the developer replenishing device of the present embodiment. 2 shows a state viewed from the back side of FIG. 1, and the arrangement of each member in the developing device is opposite to that in FIG. Further, the developing device 3a disposed in the image forming unit Pa in FIG. 1 will be described here, but the configuration of the developing devices 3b to 3d disposed in the image forming units Pb to Pd is basically the same, and thus described. Is omitted.

  As shown in FIG. 2, the developing device 3a includes a developing container (casing) 20 in which a two-component developer (hereinafter simply referred to as a developer) is accommodated. The developing container 20 is separated by partition walls 20a and 20b. The agitating and conveying chamber 21, the supply and conveying chamber 22, and the recovery and conveying chamber 23 are partitioned. In the agitating / conveying chamber 21 and the supply / conveying chamber 22, the agitating / conveying screw 25 a for supplying toner (positively charged toner) supplied from the toner container 4 a (see FIG. 1) with the carrier, agitating and charging, and the supplying and conveying Each screw 25b is rotatably arranged. In addition, a collection conveyance chamber 23 provided above the vicinity of the boundary between the supply conveyance chamber 22 and the stirring conveyance chamber 21 has a collection conveyance screw 25c for conveying the developer peeled off from a magnetic roller 30 (described later). It is rotatably arranged.

  Then, the developer is agitated by the agitating and conveying screw 25a and the supply and conveying screw 25b while being conveyed in the axial direction (perpendicular to the paper surface of FIG. 2), and passes through the developer (not shown) formed at both ends of the partition wall 20a. It circulates between the stirring and conveying chamber 21 and the supply and conveying chamber 22 through the path. Further, the developer peeled off from the magnetic roller 30 (described later) is transported in the axial direction by the recovery transport screw 25c, and the developer in the supply stirring chamber 22 from a communication portion (not shown) formed at one end of the partition wall 20b. To join. That is, a developer circulation path is formed in the developer container 20 by the agitation transport chamber 21, the supply transport chamber 22, the recovery transport chamber 23, the developer passage, and the communication portion.

  The developing container 20 extends obliquely upward to the right in FIG. 2. A magnetic roller 30 is disposed in the developing container 20 above the feeding and conveying screw 25 b, and a developing roller 31 is disposed obliquely to the upper right of the magnetic roller 30. Opposed. The developing roller 31 faces the photosensitive drum 1a (see FIG. 1) on the opening side (the right side in FIG. 2) of the developing container 20, and the magnetic roller 30 rotates counterclockwise in the figure with respect to the respective rotation axes. The developing roller 31 rotates counterclockwise in the figure.

  A toner concentration sensor (not shown) is disposed in the agitating / conveying chamber 21 so as to face the agitating / conveying screw 25a, and is agitated and conveyed from the toner container 4a via a toner supply port (not shown) based on the detection result of the toner concentration sensor. The chamber 21 is supplied with toner. As the toner concentration sensor, for example, a magnetic permeability sensor that detects the magnetic permeability of a two-component developer composed of toner and magnetic carrier in the developing container 20 is used.

  The magnetic roller 30 is composed of a non-magnetic rotating sleeve that rotates counterclockwise in FIG. 2 and a fixed magnet body that has a plurality of magnetic poles contained in the rotating sleeve.

  The developing roller 31 includes a cylindrical developing sleeve that rotates counterclockwise in FIG. 2 and a developing roller-side magnetic pole fixed in the developing sleeve. The magnetic roller 30 and the developing roller 31 face each other. It faces with a predetermined gap at (opposite position). The developing roller side magnetic pole has a different polarity from the opposing magnetic pole (main pole) of the fixed magnet body.

  Further, a spike cutting blade 35 is attached to the developing container 20 along the longitudinal direction of the magnetic roller 30 (perpendicular to the paper surface of FIG. 2), and the spike cutting blade 35 rotates in the direction of rotation of the magnetic roller 30 (see FIG. In the counterclockwise direction), it is positioned upstream of the position where the developing roller 31 and the magnetic roller 30 face each other. A slight gap (gap) is formed between the tip of the ear cutting blade 35 and the surface of the magnetic roller 30.

  A DC voltage (hereinafter referred to as Vslv (DC)) and an AC voltage (hereinafter referred to as Vslv (AC)) are applied to the developing roller 31, and a DC voltage (hereinafter referred to as Vmag (DC)) is applied to the magnetic roller 30. And an alternating voltage (hereinafter referred to as Vmag (AC)) is applied. These DC voltage and AC voltage are applied to the developing roller 31 and the magnetic roller 30 from a developing bias power source via a bias control circuit (both not shown).

  As described above, the developer is agitated by the agitating / conveying screw 25a and the supply / conveying screw 25b, and the toner is charged by circulating through the agitating / conveying chamber 21 and the supplying / conveying chamber 22 in the developing container 20, and the supply / conveying screw 25b. The developer is conveyed to the magnetic roller 30. Then, a magnetic brush (not shown) is formed on the magnetic roller 30, and the layer thickness of the magnetic brush on the magnetic roller 30 is regulated by the earbrushing blade 35, and then the opposite portion between the magnetic roller 30 and the developing roller 31. A thin toner layer is formed on the developing roller 31 by the potential difference ΔV between the Vmag (DC) conveyed and applied to the magnetic roller 30 and the Vslv (DC) applied to the developing roller 31 and a magnetic field.

  The toner layer thickness on the developing roller 31 varies depending on the resistance of the developer and the difference in rotational speed between the magnetic roller 30 and the developing roller 31, but can be controlled by ΔV. When ΔV is increased, the toner layer on the developing roller 31 is thickened, and when ΔV is decreased, the toner layer is thinned. The range of ΔV at the time of development is generally about 100V to 350V.

  The toner thin layer formed on the developing roller 31 by the magnetic brush is conveyed to an opposing portion (opposing region) between the photosensitive drum 1 a and the developing roller 31 by the rotation of the developing roller 31. Since Vslv (DC) and Vslv (AC) are applied to the developing roller 31, the toner flies due to a potential difference with the photosensitive drum 1a, and the electrostatic latent image on the photosensitive drum 1a is developed. .

  The remaining toner that is not used for development is conveyed again to the opposite portion between the developing roller 31 and the magnetic roller 30 and is collected by the magnetic brush on the magnetic roller 30. Then, the magnetic brush is peeled off from the magnetic roller 30 at the same pole portion of the fixed magnet body, and then falls into the collection conveyance chamber 23. The developer in the collection conveyance chamber 23 is conveyed in the axial direction by the collection conveyance screw 25c, and merges with the developer in the supply conveyance chamber 22 from a communication portion (not shown).

  Thereafter, a predetermined amount of toner is replenished from the toner replenishing port 20c based on a detection result of a toner concentration sensor (not shown), and is uniformly made to an appropriate toner concentration again while circulating through the supply conveyance chamber 22 and the agitation conveyance chamber 21. It becomes a charged two-component developer. This developer is again supplied onto the magnetic roller 30 by the supply stirring screw 25 b to form a magnetic brush, and is conveyed to the ear cutting blade 35.

  FIG. 3 is a schematic side cross-sectional view showing the configuration around the conveying member in the developer supply device of the present embodiment, and FIG. 4 is a schematic perspective view showing the configuration around the drive transmission member and the optical sensor. 5 is a schematic perspective view showing a drive transmission member. In FIG. 4, the upper wall of the casing 45 is omitted. Moreover, the same code | symbol is attached | subjected to the part which is common in FIG.1 and FIG.2, and description is abbreviate | omitted. The toner container 4a disposed above the developing device 3a includes a toner storage unit 41, a toner transport unit 44, and a toner supply unit 55. The toner storage container 42, the casing 45, and the toner supply unit 55 are entirely included. As one storage container is formed.

  The toner storage unit 41 is provided with a toner storage container 42 that has a connection part 42a with the toner transport part 44 and stores toner, and a toner supply screw 43 disposed in the connection part 42a. The toner agitated by a stirring paddle (not shown) in the toner container 42 is supplied to the toner conveying portion 44 by the toner supply screw 43.

  A toner transport unit 44 is disposed below the toner storage unit 41. The toner transport unit 44 includes a casing 45 and a toner transport screw (transport member) 46 disposed in the casing 45. Yes. The toner conveying screw 46 conveys the toner supplied from the toner storage unit 41 to the downstream side (right side in FIG. 3). Further, the bottom surface of the casing 45 on the downstream side (right side in FIG. 3) 45a in the toner conveyance direction is connected to and communicates with the toner replenishing portion 55.

  The toner replenishing portion 55 is formed of a cylindrical member arranged in the vertical direction of the drawing, and the upper end of the toner replenishing portion 55 is connected to the toner transport portion 44 as described above, and the lower end is the toner replenishing port 20c of the developing container 20. Connected to and in communication with this. The toner transported by the toner transport screw 46 passes through the toner replenishing section 55 and is replenished to the developing container 20 through the toner replenishing port 20c.

  An upstream end (left side in FIG. 3) of the casing 45 in the toner conveyance direction is detachably attached to the casing 45, and a support portion 47 constituting a part of the casing 45 by being attached to the casing 45 is provided. ing. An upstream end 46aa in the toner transport direction of the rotation shaft 46a of the toner transport screw 46 is rotatably supported by a boss 47a formed on the support 47, and a downstream end 46ab is a downstream end of the casing 45. It is rotatably supported by a boss 45aa formed on 45a.

  Further, a drive transmission member 49 having a drive transmission gear portion 49a and a flange portion 49b formed integrally with the drive transmission gear portion 49a is provided at the upstream end portion 46aa. The drive transmission member 49 is fitted to the upstream end 46aa and is engaged with the upstream end 46aa by a pin (not shown) to move the drive transmission member 49 in the circumferential direction with respect to the rotation shaft 46a. Is regulated. Thereby, the drive transmission member 49 rotates with the rotating shaft 46a.

  As shown in FIG. 4, the drive transmission gear portion 49 a meshes with a worm gear 53 a that protrudes from the drive motor 53 via two idle gears 51 and 52. Here, a brush motor is used as the drive motor 53, and the worm gear 53 a rotates with the rotation of the drive motor 53. Thereby, the rotational driving force of the drive motor 53 is transmitted to the drive transmission gear portion 49, and the toner conveying screw 46 can be rotated.

  As shown in FIGS. 4 and 5, the flange portion 49b is perpendicular to the axial direction from the drive transmission gear portion 49a (up and down direction in FIGS. 4 and 5) and has the same center as the drive transmission gear portion 49a. It is formed in a disk shape (circular shape). Further, as shown in FIG. 5, a plurality of protrusions 49ba are formed at a circumferential interval in the peripheral portion of the flange portion 49b, and a plurality of slits 50 are formed by gaps between adjacent protrusions 49ba. Has been.

  As shown in FIG. 3, a through hole 47b is formed at a position facing the lower end of the flange portion 49b in the support portion 47, and an optical sensor (detection means) 51 is fitted into the through hole 47b. . The optical sensor 51 has a light emitting part 51a and a light receiving part 51b, both of which project toward the flange part 49b side (right side in the figure) along the axial direction (left and right direction in the figure). In addition, the light emitting part 51a and the light receiving part 51b are arranged at a certain distance from each other in the direction perpendicular to the axial direction (up and down direction in the figure), and a protruding part positioned below in the flange part 49b between them. 49ba is sandwiched in a non-contact manner.

  As a result, when the drive transmission member 49 rotates and the protrusion 49ba and the slit 50 rotate, the light transmission unit 51a and the light receiving unit 51b sequentially pass. When the protrusion 49ba passes between the two, the light emitted from the light emitting portion 51a is blocked, so that the amount of light received by the light receiving portion 51b decreases, and when the slit 50 passes, the light emitted from the light emitting portion 51a is reduced. Since the light is not blocked, the amount of light received by the light receiving unit 51b does not decrease.

  As a result, the amount of light received by the light receiving unit 51b becomes a pulse waveform, and the rotation amount of the drive transmission member 49, that is, the rotation amount of the toner conveying screw 46 can be detected by counting the number of pulses in the pulse waveform. At this time, since the drive transmission gear portion 49a and the flange portion 49b are integrally formed, it is not necessary to detect the rotation amount of the drive transmission member 49 via the rotation shaft 46a or the like.

  As shown in FIGS. 3 and 4, a substantially U-shaped engaging portion 51c that opens downward is provided on the lower end portion of the optical sensor 51 on the side opposite to the flange portion 49b (outside, FIG. 3). A locking piece 51d protruding outward is formed at the end of the left side. Then, the optical sensor 51 is inserted into the through-hole 47b of the support portion 47 from the outside, and the engagement portion 51c is fitted with an engagement protrusion 47c that protrudes upward from the lower end portion of the support portion 47. The optical sensor 51 can be fixed to the support portion 47 by engaging 51 d with the peripheral edge portion of the through hole 47 b of the support portion 47.

  The downstream end 46ab of the rotating shaft 46a is supported by the downstream end 45a of the casing 45, the drive transmission member 49 is fitted to the upstream end 46aa, and the support 47 to which the optical sensor 51 is attached is provided. By mounting on the casing 45, the drive transmission member 49 is pressed against the protruding end of the boss portion 47 a of the support portion 47 and positioned in the axial direction. Further, the light emitting part 51a and the light receiving part 51b of the optical sensor 51 are arranged at positions where the projecting part 49ba arranged below the flange part 49b is sandwiched in a non-contact manner.

  Next, adjustment of the rotation amount of the toner conveying screw 46 using the optical sensor 51 will be described. FIG. 6 is a diagram schematically showing a state in which the slit is overrun. In FIG. 6, an alternate long and short dash line arrow indicates a traveling direction (rotating direction) of the slit 50.

  The rotation speed of the toner conveying screw 46 is set in advance. The toner replenishment amount is calculated by a control unit (not shown) based on a detection result of a toner density detection sensor (not shown), and the rotation amount of the toner conveying screw 46 is calculated based on the calculated toner supply amount. . The toner is replenished from the toner container 4a to the developing device 3a by repeatedly operating and stopping the toner conveying screw 46 based on the rotation amount (intermittent operation).

  When the toner conveying screw 46 rotates (when toner is replenished), the optical sensor 51 detects the slit 50 formed in the flange portion 49b, whereby the rotation amount of the toner conveying screw 46 is detected.

  Here, when the rotational performance of the drive motor 53 varies, such as when the rise performance of the drive motor 53 varies or when the brake performance varies when a small amount of toner is replenished, as shown in FIG. In addition, an overrun may occur in the toner conveying screw 46.

  When the overrun occurs, the slit 50 (shown as A in FIG. 6) that should stop between the light emitting part 51a and the light receiving part 51b of the optical sensor 51 (shown as A in FIG. 6) is advanced from the target position. Become. As a result, the number of pulses (that is, the number of slits) detected by the optical sensor 51 increases, and more toner is supplied to the developing container 20 (see FIG. 3) than necessary.

  Therefore, the increment n of the pulse is calculated, and the number of pulses at the next rotation of the toner conveying screw 46 is reduced by the increment n from the number of pulses calculated from the detection result of the toner density sensor (not shown). It was. As a result, the toner replenishment amount can be reduced by the amount replenished during the previous rotation, so that the toner replenishment amount from the toner container 4a to the developing container 20 can be adjusted appropriately.

  As described above, in the present embodiment, the drive transmission gear portion 49a to which the rotational drive from the drive motor 53 is transmitted to the upstream end portion 46aa (one end portion in the axial direction) of the rotation shaft 46a of the toner conveying screw 46, It is formed integrally with the drive transmission gear portion 49a, protrudes along the vertical direction with respect to the axial direction, is formed in a substantially circular shape around the rotation axis, and is arranged concentrically around the rotation shaft 46a. A drive transmission member 49 having a flange portion 49b having a slit 50 is provided, and a light emitting portion 51a that is arranged to sandwich the peripheral portion of the flange portion 49b and can emit light to the slit 50, and is emitted from the light emitting portion 51a. And an optical sensor 51 that detects the amount of rotation of the toner conveying screw 46 by reading a pulse waveform from the slit 50. Because, the amount of rotation of the drive transmission member 49, it is not necessary to detect through a rotary shaft 46a and the like.

  Accordingly, the rotation amount of the toner conveying screw 46 is not affected by the displacement of the rotation shaft 46a, the displacement of the rotation shaft 46a and the drive transmission gear portion 49a, the displacement of the rotation shaft 46a and the flange portion 49b, and the like. Can be detected. Therefore, the rotation amount of the toner conveying screw 46 can be detected stably. Furthermore, the toner replenishment amount to the developing device 3a can be stabilized. In addition, the apparatus main body can be downsized.

  Further, in this embodiment, the support portion 47 that is detachable from the casing 45 and constitutes a part of the outer wall of the casing 45 is provided, and the optical sensor 51 is attached to the support portion 47, so that the support portion 47 is attached to the casing 45. Only the positioning of the flange portion 49b and the optical sensor 51 can be performed.

  Thereby, the position shift with the flange part 49b and the optical sensor 51 at the time of an assembly etc. can be prevented. Therefore, the rotation amount of the toner conveying screw 46 can be detected more stably. Further, even if a positional deviation or the like occurs, it is effective because the positional relationship between the two can be easily readjusted by detaching the support portion 47 from the casing 45. Furthermore, further miniaturization can be achieved and assembly is facilitated. However, the support portion 47 can also be formed integrally with the casing 45.

  In the present embodiment, the slit 50 is formed from the gap between the plurality of protruding portions 49ba that protrude substantially perpendicularly from the peripheral edge of the flange portion 49b, so that detection by the optical sensor 51 is facilitated. Further, when the optical sensor 51 is detachably attached to the support portion 47 as described above, the slit 50 can be detected simply by projecting the light emitting portion 51a and the light receiving portion 51b from the support portion 47 along the axial direction. It becomes possible.

  Thereby, the optical sensor 51 can be attached without difficulty, and the detection of the optical sensor 51 can be stabilized. However, the shape or the like of the flange portion 49b is not particularly limited to the present embodiment, and can be appropriately set according to the device configuration and the like.

  FIG. 7A is a front view showing a modified example of the drive transmission member together with the optical sensor, and FIG. 7B is a view of FIG. 7A viewed from the right. For example, as shown in FIGS. 7A and 7B, the flange portion 49b can be formed in a flat circular shape, and the slit 50 can be formed in the peripheral portion thereof. In such a case, the light emitting part 51a and the light receiving part 51b of the optical sensor 51 may be disposed along the flange part 49b.

  In the present embodiment, the number of pulses generated by the rotation of the toner conveying screw 46 is counted based on the detection result of the optical sensor 51, and the toner conveying screw 46 is rotated at the next rotation according to the counted number of pulses. Since the rotation amount is adjusted, the rotation amount can be appropriately adjusted even when the drive motor 53 such as a brush motor that tends to vary in the rotation speed is used. Thereby, the toner replenishment amount to the developing device 3a can be stabilized.

  Further, in this embodiment, when the toner conveying screw 46 overruns the target number of pulses, the toner conveying screw 46 is reduced by the increased number of pulses (increment n) at the next rotation of the toner conveying screw 46 (at the time of toner replenishment). This is effective because the toner replenishment amount can be adjusted to an appropriate amount even when the rising performance and braking performance of the drive motor 53 vary. In addition, when the rotation of the toner conveying screw 46 is smaller than the target number of pulses, the amount of rotation at the next rotation of the toner conveying screw 46 can be adjusted by increasing the number of decreased pulses.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the number, shape, and the like of the slit 50 shown in the above embodiment are merely examples, and can be set as appropriate according to the detection accuracy of the rotation amount, the configuration of the optical sensor 51, other device configurations, and the like. Moreover, in the said embodiment, although the drive motor 53 formed from a brush motor was used, if a rotational drive can be transmitted to the drive transmission gear part 49a, another motor can also be used.

  In the above-described embodiment, the present invention uses a two-component developer, forms a magnetic brush on the magnetic roller 30, moves only the toner from the magnetic roller 30 to the developing roller 31, and then develops the photosensitive drum from the developing roller 31. The present invention is applied to the developing devices 3a to 3d that supply toner to 1a to 1d. However, the present invention is also applied to a developing device that uses a one-component developer, or a developing device that has only the developing roller 31 without the magnetic roller 30. Can do. In the above embodiment, the tandem type color image forming apparatus 100 is used. However, the present invention can also be applied to, for example, a copying machine, a multifunction machine, and a facsimile, and can also be applied to a monochrome multifunction machine, a printer, a fax machine, and the like. Needless to say, it can be done.

  The present invention is arranged at one end in the axial direction of the rotation shaft of the conveying member, and is formed integrally with the drive transmission gear portion to which the rotational drive from the driving means is transmitted, and is perpendicular to the axial direction. A drive transmission member having a flange portion that protrudes along the direction and has a slit portion that is formed in a substantially circular shape around the rotation axis and that is concentrically arranged around the rotation axis; and A light emitting unit that is arranged with a peripheral portion interposed therebetween and capable of emitting light to the slit, and a light receiving unit capable of receiving light emitted from the light emitting unit, and reading a pulse waveform by the slit to And a developer replenishing device provided with a detecting means for detecting a rotation amount.

  Thereby, the developer replenishment amount to the developing device can be stabilized. Further, by using the image forming apparatus provided with the developer replenishing means, it is possible to stabilize the amount of developer replenished to the developing apparatus and improve the image quality.

Pa to Pd Image forming unit 1a to 1d Photosensitive drum 3a to 3d Developing device 4a to 4d Toner container (developer supply device)
DESCRIPTION OF SYMBOLS 20 Developing container 20a, 20b Partition wall 20c Toner replenishment port 30 Magnetic roller 31 Developing roller 35 Ear cutting blade 41 Toner container 42 Toner container (accommodating container)
44 Toner transport unit 45 Casing (container)
46 Toner conveying screw (conveying member)
46a Rotating shaft 46aa Upstream end (one axial end)
46ab downstream end portion 47 support portion 47a boss portion 47b through hole 47c engagement protrusion 49 drive transmission member 49a drive transmission gear portion 49b flange portion 49ba projection portion 50 slit 51 optical sensor (detection means)
51a Light emitting part 51b Light receiving part 51c Engagement hole 51d Projection part 55 Toner replenishing part (container)
100 color printer (image forming device)

Claims (6)

A developer replenishing device comprising: a housing container that contains a developer for replenishing the developing device; and a transport member that supplies the developing device while rotating the developer in the housing container,
A drive transmission gear portion, which is disposed at one axial end portion of the rotation shaft of the transport member and transmits the rotational drive from the drive means, is formed integrally with the drive transmission gear portion, and is perpendicular to the axial direction. A drive transmission member having a flange portion that protrudes along and is formed in a substantially circular shape centered on the rotation axis, and has a slit arranged concentrically around the rotation axis;
A pulse waveform generated by the slit, having a light emitting part that is disposed across a peripheral edge of the flange part and capable of emitting light to the slit, and a light receiving part capable of receiving light emitted from the light emitting part. And a detecting means for detecting the amount of rotation of the conveying member. A support portion is provided which is detachable from the storage container and constitutes a part of the outer wall of the storage container.
The developer supply device according to claim 1, wherein the detection unit is attached to the support portion.   The developer replenishing device according to claim 1, wherein the slit is formed by a gap between protrusions protruding substantially perpendicularly from a peripheral edge portion of the flange portion.   The number of pulses generated by the rotation of the conveying member is counted based on the detection result of the detecting means, and the amount of rotation at the next rotation of the conveying member is adjusted according to the counted number of pulses. The developer supply device according to claim 1.   When it is detected that the conveying member has overrun the target pulse number, the rotation amount at the next rotation of the conveying member is adjusted by reducing the number of pulses increased from the target pulse number. The developer replenishing device according to claim 4.   An image forming apparatus comprising the developer supply device according to claim 1.

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