JP2014206767A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can effectively suppress toner from being accumulated to aggregate on the periphery of a thickness regulating member.SOLUTION: The present developing devices 3a to 3d each include a developing roller 31, a toner supply roller 30 that supplies toner to the developing roller 31, a thickness regulating member 32 that is arranged opposite to the toner supply roller 30 at a predetermined distance to regulate the thickness of the toner carried on the toner supply roller 30, and a developing container 20 that accommodates the developing roller 31, toner supply roller 30, and thickness regulating member 32. The thickness regulating member 32 is formed into a roller shape and rotatable.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus including the developing device, and in particular, a developing device including a developing roller that supplies toner to an image carrier and a toner supply roller that supplies toner to the developing roller, and an image including the developing device. The present invention relates to a forming apparatus.

  An electrophotographic image forming apparatus irradiates a peripheral surface of an image carrier (photosensitive drum) with light based on image information read from an original image or image information transmitted from an external device such as a computer. An electrostatic latent image is formed, toner is supplied from the developing device to the electrostatic latent image to form a 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.

  By the way, in recent years, in the image forming apparatus, the configuration of the apparatus becomes complicated with the progress of color printing and high-speed processing, and the toner stirring member in the developing device is forced to rotate at high speed to cope with high-speed processing. . In particular, in a development method using a two-component developer including a magnetic carrier and a toner and using a magnetic roller (toner supply roller) that carries the developer and a development roller that carries only the toner, the development roller and the magnetic roller In the opposite portion, only the toner is carried on the developing roller by the magnetic brush formed on the magnetic roller, and the toner that was not used for development is peeled off from the developing roller. For this reason, the toner easily floats in the vicinity of the facing portion between the developing roller and the magnetic roller, and the floating toner accumulates around the panicle blade (thickness regulating member), and the accumulated toner aggregates to the developing roller. If it adheres, there is a risk that the toner will fall out and an image defect will occur.

  Therefore, for example, Patent Document 1 discloses a developing device that uses a two-component developer including a magnetic carrier and a toner, uses a magnetic roller that carries the developer, and a developing roller that carries only the toner. A developing device is disclosed in which an air inflow hole for taking in air from the outside of the developing device is provided in a wall portion facing the roller and the magnetic roller, thereby generating an air flow that directs the floating toner around the panicle blade. Yes.

JP 2010-276654 A

  However, even when the air inflow hole is provided as in Patent Document 1, when the apparatus main body is increased in speed and the toner floating amount is large, the floating toner is generated in the air flow generated by the rotation of the magnetic roller and the developing roller. It is difficult to get enough. For this reason, toner may accumulate and aggregate around the cutting blade.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to develop a toner that can effectively suppress the accumulation and aggregation of toner around the thickness regulating member. The present invention provides an apparatus and an image forming apparatus including the apparatus.

  In order to achieve the above object, a developing device according to the present invention is arranged to face an image carrier on which an electrostatic latent image is formed and to supply toner to the image carrier in a region facing the image carrier. A toner supply roller that is disposed opposite to the development roller and a toner supply roller that supplies toner to the development roller in a region facing the development roller, and is disposed opposite the toner supply roller at a predetermined interval and is carried by the toner supply roller. A thickness regulating member that regulates the thickness of the toner to be discharged, and a casing that accommodates the developing roller, the toner supply roller, and the thickness regulating member, and the thickness regulating member is disposed below a region where the developing roller and the toner supply roller are opposed to each other. It is arranged and formed in a roller shape, and can rotate in the same direction as the rotation direction of the toner supply roller during the developing operation.

  In this developing device, as described above, the thickness regulating member is formed in a roller shape and is rotatable. Thus, by rotating the thickness regulating member, the toner that floats and accumulates on the thickness regulating member can be dropped. For this reason, it is possible to effectively suppress the accumulation and aggregation of the toner on the thickness regulating member. As a result, it is possible to effectively suppress the agglomerated toner from adhering to the developing roller, and thus it is possible to effectively suppress the occurrence of image defects.

  In the developing device, the thickness regulating member preferably includes a rotatable hollow cylindrical portion and a magnetic body disposed in the cylindrical portion so as to face the toner supply roller. According to this configuration, it is possible to easily regulate the thickness of the toner carried on the toner supply roller while suppressing toner aggregation on the thickness regulating member.

  In the developing device, preferably, the thickness regulating member rotates while the developing operation is stopped. If comprised in this way, it can suppress that the thickness of the toner borne by the toner supply roller deviates from the set value.

  In this case, preferably, the toner supply roller rotates in a direction opposite to the thickness regulating member when the thickness regulating member rotates. Thereby, in the opposing area | region of a toner supply roller and a thickness control member, the opposing surfaces of a toner supply roller and a thickness control member move (rotate) in the same direction. For this reason, the toner deposited on the thickness regulating member rotates along with the surface of the toner supply roller and smoothly passes between the thickness regulating member and the toner supply roller. Thereby, the toner on the thickness regulating member can be smoothly dropped.

  In the developing device, preferably, the thickness regulating member rotates at a lower speed than the rotation speed of the toner supply roller during the developing operation. If comprised in this way, it can suppress that the toner deposited on the thickness control member by rotation of the thickness control member floats again. As a result, it is possible to prevent the toner from adhering to the toner supply roller and the developing roller and causing the toner thickness to become larger than the set value, and the toner to leak to the outside of the casing.

  The image forming apparatus of the present invention includes the developing device having the above-described configuration. According to this configuration, it is possible to obtain an image forming apparatus capable of effectively suppressing toner accumulation and aggregation around the thickness regulating member.

  In this case, preferably, the thickness regulating member rotates every time the predetermined number of printed sheets is reached. If comprised in this way, the toner on a thickness control member can be dropped efficiently, suppressing rotation operation of a thickness control member to the required minimum.

  As described above, according to the present invention, it is possible to easily obtain a developing device and an image forming apparatus including the developing device capable of effectively suppressing toner accumulation and aggregation around the thickness regulating member. it can.

1 is a cross-sectional view schematically showing the structure of an image forming apparatus according to an embodiment of the present invention. 1 is a side cross-sectional view illustrating a structure of a developing device according to an embodiment of the present invention. FIG. 3 is a side cross-sectional view illustrating a structure around a thickness regulating member of the developing device according to the embodiment of the present invention. It is side surface sectional drawing which showed the structure of the image development apparatus of the modification of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  The structure of the image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. In the main body of the image forming apparatus 100 (here, a color printer), four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (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.

  These image forming units Pa to Pd are provided with photosensitive drums (image carriers) 1a, 1b, 1c and 1d for carrying visible images (toner images) of the respective colors, and further, driving means (FIG. 1), an intermediate transfer belt 8 that rotates clockwise in FIG. 1 is provided adjacent to each of 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. Thereafter, the toner image primarily transferred onto the intermediate transfer belt 8 is secondarily transferred onto a transfer paper P as an example of a recording medium by the action of the secondary transfer roller 9. Further, the transfer paper P on which the toner image is secondarily transferred is discharged from the main body of the image forming apparatus 100 after the toner image is fixed in the fixing unit 13. 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 on which the toner image is secondarily transferred is housed in a paper cassette 16 disposed at the lower part of the main body of the image forming apparatus 100, and is transferred to the secondary transfer roller via the paper feed roller 12a and the registration roller pair 12b. 9 and a nip portion between a later-described intermediate transfer belt 8 and a driving 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. Further, a blade-like belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side 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 devices 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 developing device 3a to 3d is less than a specified value due to the formation of a toner image to be described later, each development from the toner containers (replenishing units) 4a to 4d is performed. The toner is supplied to the 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.

  The primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d. A black toner image is 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, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer is removed by the cleaning units 7a to 7d.

  The intermediate transfer belt 8 is stretched over an upstream driven 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 pair 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 secondarily transferred onto the transfer paper P. The transfer sheet P on which the toner image is secondarily transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressed by the fixing roller pair 13a to fix the toner image on the surface of the transfer paper P, and 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 on only one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller pair 15.

  On the other hand, when images are formed on both sides of the transfer paper P, a part of the transfer paper P that has passed through the fixing unit 13 is once protruded from the discharge roller pair 15 to the outside of the apparatus. Then, after the trailing edge of the transfer paper P has passed through the branch portion 14, the discharge roller pair 15 is rotated in the reverse direction and the transport direction of the branch portion 14 is switched. As a result, the transfer paper P is distributed from the rear end to the paper transport path 18 and is transported again to the secondary transfer nip portion with the image surface reversed. Then, the next toner image formed on the intermediate transfer belt 8 is secondarily transferred to the surface of the transfer paper P on which the image is not formed by the secondary transfer roller 9. The transfer paper P onto which the toner image has been secondarily transferred is conveyed to the fixing unit 13 where the toner image is fixed and then discharged onto the discharge tray 17.

  Next, the detailed structure of the developing device 3a will be described with reference to FIG. 2 shows a state viewed from the back side of FIG. 1, and the arrangement of each member in the developing device 3a is opposite to that in FIG. Further, in the following description, the developing device 3a disposed in the image forming unit Pa of FIG. 1 is illustrated, but the configuration of the developing devices 3b to 3d disposed in the image forming units Pb to Pd is basically the same. Therefore, explanation 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, and the developing container 20 is stirred and conveyed by a partition wall 20a. It is divided into a chamber 21 and a supply transfer chamber 22. In the agitating / conveying chamber 21 and the supply / conveying chamber 22, the agitating / conveying screw 23 a and the supplying and conveying the toner (positively charged toner) supplied from the toner container 4 a (see FIG. 1) are mixed with the carrier and agitated and charged. Each screw 23b is rotatably arranged.

  The developer is agitated by the agitating / conveying screw 23a and the supply / conveying screw 23b and conveyed in the axial direction (perpendicular to the paper surface of FIG. 2) to pass 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. That is, a developer circulation path is formed in the developer container 20 by the agitating / conveying chamber 21, the supply / conveying chamber 22, and the developer passage.

  The developing container 20 extends obliquely upward and to the right of FIG. 2, a toner supply roller 30 is disposed above the supply and conveyance screw 23 b in the developing container 20, and the developing roller is disposed to the right and upward of the toner supply roller 30. 31 are arranged opposite to each other. The developing roller 31 faces the photosensitive drum 1a (see FIG. 1) on the opening side of the developing container 20 (right side in FIG. 2). The toner supply roller 30 and the developing roller 31 rotate in the counterclockwise direction in FIG.

  In the agitating / conveying chamber 21, a toner concentration sensor (not shown) is disposed so as to face the agitating / conveying screw 23a, and agitation is performed from the toner container 4a via a toner supply port (not shown) based on the detection result of the toner concentration sensor. The transfer 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 toner supply roller 30 is a magnetic roller composed of a non-magnetic rotating sleeve that rotates counterclockwise in FIG. 2 and a fixed magnet body having 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 that is fixed in the developing sleeve. The toner supply roller 30 and the developing roller 31 are opposed to each other at a facing position (opposing position) with a predetermined gap. The developing roller side magnetic pole has a different polarity from the opposing magnetic pole (main pole) of the fixed magnet body.

  A thickness regulating member 32 that regulates the thickness of the developer carried on the toner supply roller 30 is attached to the developing container 20 along the longitudinal direction of the toner supply roller 30 (direction perpendicular to the paper surface of FIG. 2). It has been. The thickness regulating member 32 is positioned upstream of the opposing position of the developing roller 31 and the toner supply roller 30 in the rotation direction of the toner supply roller 30 (counterclockwise direction in the drawing). Further, the thickness regulating member 32 is disposed below a facing portion (facing region) between the developing roller 31 and the toner supply roller 30. A slight gap (gap) is formed between the surface of the thickness regulating member 32 and the surface of the toner supply 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. The toner supply roller 30 is applied with a direct voltage (hereinafter referred to as Vmag (DC)) and an alternating voltage (hereinafter referred to as Vmag (AC)). These DC voltage and AC voltage are applied from the developing bias power source to the developing roller 31 and the toner supply roller 30 via a bias control circuit (both not shown).

  As described above, the toner in the developer is charged by circulating the agitating and conveying chamber 21 and the supplying and conveying chamber 22 in the developing container 20 while the developer is agitated by the agitating and conveying screw 23a and the supply and conveying screw 23b. The developer in the supply conveyance chamber 22 is conveyed to the toner supply roller 30 by the supply conveyance screw 23b. Then, a magnetic brush (not shown) is formed on the toner supply roller 30. After the layer thickness of the magnetic brush on the toner supply roller 30 is regulated by the thickness regulating member 32, the magnetic brush is conveyed to the opposite portion between the toner supply roller 30 and the developing roller 31 by the rotation of the toner supply roller 30. A thin toner layer is formed on the developing roller 31 by a potential difference ΔV between Vmag (DC) applied to the toner supply roller 30 and Vslv (DC) applied to the developing roller 31 and a magnetic field.

  The thickness of the toner layer on the developing roller 31 varies depending on the resistance of the developer, the rotational speed difference between the toner supply roller 30 and the developing roller 31, and the like, 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 contact with the magnetic brush on the toner supply roller 30 is conveyed to a facing portion (facing region) between the photosensitive drum 1 a and the developing roller 31 by the rotation of the developing roller 31. The Since Vslv (DC) and Vslv (AC) are applied to the developing roller 31, the toner flies from the developing roller 31 to the photosensitive drum 1a due to a potential difference between the developing roller 31 and the photosensitive drum 1a. The electrostatic latent image is developed.

  Remaining toner that is not used for development is conveyed again to the opposite portion between the developing roller 31 and the toner supply roller 30 and is collected by the magnetic brush on the toner supply roller 30. The magnetic brush is peeled off from the toner supply roller 30 at the same polarity portion of the fixed magnet body, and then falls into the supply conveyance chamber 22.

  Thereafter, a predetermined amount of toner is replenished from a toner replenishing port (not shown) based on a detection result of a toner concentration sensor (not shown), and an appropriate toner concentration is again obtained while circulating through the supply transport chamber 22 and the stirring transport chamber 21. The two-component developer is uniformly charged. This developer is again supplied onto the toner supply roller 30 by the supply / conveyance screw 23b to form a magnetic brush, and is conveyed to the thickness regulating member 32.

  The thickness regulating member 32 is formed in a roller shape and is rotatable. Specifically, the thickness regulating member 32 includes a hollow cylindrical portion 32a that rotates counterclockwise in FIG. 2 (the same direction as the rotation direction of the toner supply roller 30 during the developing operation), and the toner supply roller 30. And a fixed magnetic body 32b disposed in the cylindrical portion 32a so as to oppose each other. The magnetic body 32b is formed of, for example, a magnetic sheet metal or a magnet.

  As shown in FIG. 3, the toner T deposited on the thickness regulating member 32 (cylindrical portion 32 a) by the cylindrical portion 32 a rotating intermittently or continuously causes the thickness regulating member 32 and the toner supply roller to move. It passes between 30 and falls into the supply transfer chamber 22.

  At this time, the cylindrical portion 32a rotates at a low speed (for example, a speed lower than the rotation speed of the toner supply roller 30 during the developing operation). Further, the cylindrical portion 32a does not rotate during the developing operation, but rotates while the developing operation is stopped. In this case, it is preferable that the toner supply roller 30 is rotated in a direction opposite to the cylindrical portion 32a (a direction opposite to that during the developing operation, a clockwise direction in FIG. 2).

  The timing for rotating the thickness regulating member 32 may be performed every time the printing operation is completed, or may be performed when the number of printed sheets reaches a predetermined number. Further, the timing of rotating the thickness regulating member 32 and the timing of rotating the toner supply roller 30 in the reverse direction (clockwise direction in FIG. 2) may be the same or different.

  In the present embodiment, as described above, the thickness regulating member 32 is formed in a roller shape and is rotatable. Thus, by rotating the thickness regulating member 32, the toner that floats and accumulates on the thickness regulating member 32 can be dropped. For this reason, it is possible to effectively suppress the accumulation and aggregation of toner on the thickness regulating member 32. As a result, it is possible to effectively suppress the agglomerated toner from adhering to the developing roller 31, and thus it is possible to effectively suppress the occurrence of image defects.

  Further, as described above, the thickness regulating member 32 includes a rotatable hollow cylindrical portion 32 a and a magnetic body 32 b disposed in the cylindrical portion 32 a so as to face the toner supply roller 30. Thereby, the thickness of the toner carried on the toner supply roller 30 can be easily regulated while suppressing the toner from aggregating on the thickness regulating member 32.

  Further, as described above, the thickness regulating member 32 rotates while the developing operation is stopped. As a result, the thickness of the toner carried on the toner supply roller 30 can be prevented from deviating from the set value.

  Further, as described above, the toner supply roller 30 may rotate in the opposite direction to the thickness regulating member 32 when the thickness regulating member 32 rotates. In this case, in the opposed region between the toner supply roller 30 and the thickness regulating member 32, the opposed surfaces of the toner supply roller 30 and the thickness regulating member 32 move (rotate) in the same direction. For this reason, the toner deposited on the thickness regulating member 32 rotates along the surface of the toner supply roller 30 and smoothly passes between the thickness regulating member 32 and the toner supply roller 30. Thereby, the toner on the thickness regulating member 32 can be dropped smoothly.

  Further, as described above, the thickness regulating member 32 rotates at a low speed (for example, a speed lower than the rotational speed of the toner supply roller 30 during the developing operation). Thereby, it is possible to prevent the toner accumulated on the thickness regulating member 32 from floating again due to the rotation of the thickness regulating member 32. As a result, it is possible to prevent the toner from adhering to the toner supply roller 30 and the developing roller 31 and the toner thickness from becoming larger than the set value, and the toner from leaking outside the developing container 20.

  Further, as described above, the thickness regulating member 32 may be rotated every time the predetermined number of prints is reached. In this case, it is possible to efficiently drop the toner on the thickness regulating member 32 while minimizing the rotational movement of the thickness regulating member 32.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a tandem type color image forming apparatus as shown in FIG. 1 is shown, the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming apparatuses having a developing device having a developing roller and a toner supply roller, such as a monochrome copying machine, a monochrome printer, a digital multifunction peripheral, and a facsimile machine.

  In the above-described embodiment, an example in which the thickness regulating member is rotated while the developing operation is stopped has been described. However, the present invention is not limited thereto, and the thickness regulating member may be rotated during the developing operation.

  In the above-described embodiment, the example in which the thickness regulating member rotates at a lower speed than the rotation speed of the toner supply roller during the developing operation has been described. However, the present invention is not limited thereto, and the thickness regulating member The toner supply roller may be rotated at a higher speed than the rotation speed of the toner supply roller during operation.

  In the above-described embodiment, the present invention uses a two-component developer, forms a magnetic brush on the toner supply roller 30, moves only the toner from the toner supply roller 30 to the development roller 31, and performs photosensitivity from the development roller 31. Although applied to the developing devices 3a to 3d for supplying toner to the body drums 1a to 1d, the present invention is not limited to this. For example, as shown in FIG. 4, the arrangement of the developing roller 31 and the toner supply roller 30 in the above embodiment is reversed, and the developing roller 31 (in this configuration, a magnetic roller having the same configuration as the toner supply roller 30 in the above embodiment) The toner is supplied to the photosensitive drums 1a to 1d by a magnetic brush made of a two-component developer held on the surface, and the toner supply roller 30 (in this configuration, the same configuration as the developing roller 31 of the above embodiment) The toner held on the surface of the developing roller 31 is supplied to the developing roller 31, and the toner supply roller 30 is used to recover the excess toner on the surface of the developing roller 31. Even in this configuration, it is possible to effectively suppress the accumulation and aggregation of toner on the thickness regulating member 32.

1a to 1d Photosensitive drum (image carrier)
3a to 3d Developing device 20 Developing container (casing)
DESCRIPTION OF SYMBOLS 30 Toner supply roller 31 Developing roller 32 Thickness control member 32a Cylindrical part 32b Magnetic body 100 Image forming apparatus T Toner

Claims (5)

A developing roller that is disposed to face an image carrier on which an electrostatic latent image is formed, and that supplies toner to the image carrier in a region facing the image carrier;
A toner supply roller that is disposed to face the developing roller and supplies toner to the developing roller in a region facing the developing roller;
A thickness regulating member that is disposed opposite to the toner supply roller at a predetermined interval and regulates the thickness of the toner carried on the toner supply roller;
A casing that houses the developing roller, the toner supply roller, and the thickness regulating member;
An image forming apparatus including a developing device including:
The thickness regulating member is disposed below a facing region between the developing roller and the toner supply roller, is formed in a roller shape, and rotates in the same direction as the rotation direction of the toner supply roller during the developing operation. Is possible,
2. The image forming apparatus according to claim 1, wherein the thickness regulating member rotates every time a predetermined number of printed sheets is reached.   The said thickness control member contains the hollow cylindrical part which can be rotated, and the magnetic body arrange | positioned in the said cylindrical part so that the said toner supply roller may be opposed. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the thickness regulating member rotates while the developing operation is stopped.   The image forming apparatus according to claim 3, wherein the toner supply roller rotates in a direction opposite to the thickness regulating member when the thickness regulating member rotates.   The image forming apparatus according to claim 1, wherein the thickness regulating member rotates at a lower speed than a rotation speed of the toner supply roller during a developing operation.

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