JP4081367B2 - Development device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device, and more particularly to a developing device that is provided in an electrophotographic image forming apparatus such as a printer, a copying machine, and a facsimile, and that supplies a single component toner to a latent image on a photosensitive member and develops it. Is.
[0002]
[Prior art]
Conventionally, an image forming apparatus of this type includes a photosensitive member as a latent image carrier and a plurality of developing devices that store toners of different colors and perform contact and separation operations on the photosensitive member. Are known. In this image forming apparatus, the toner images of the respective colors sequentially developed by the respective developing devices are transferred onto the transfer material by superimposing the superimposed toner images on the photosensitive member, or the respective colors on the photosensitive member developed by the respective developing devices. The toner images are sequentially superimposed and transferred on the intermediate transfer member, and the superimposed toner images on the intermediate transfer member are collectively transferred onto a transfer material, whereby a color image is formed.
[0003]
Further, as a developing device used in this type of image forming apparatus, a one-component developer composed of toner particles to which an additive such as toner particles or an auxiliary agent is externally added, that is, a developer containing no carrier particles is used as a developer. There is known a one-component developing type developing device that supplies a developing roller as a carrier and forms a toner layer having a predetermined thickness on the developing roller. This type of developing device does not need to control the toner concentration (no toner concentration sensor is required), compared to a two-component developing type developing device using a two-component developer composed of toner and carrier, and Since there is no need for mixing and stirring means for mixing and stirring the toner and the carrier, there is an advantage that the maintenance and management of the apparatus is simplified, and the apparatus can be reduced in size and cost.
[0004]
In the above one-component developing type developing apparatus, there are known a non-magnetic toner and a magnetic toner as a one-component developer. Regardless of which toner is used, a developer layer regulating member for forming a toner layer having a predetermined layer thickness is provided on the developing roller. In the one-component developing type developing device using non-magnetic toner, the toner layer regulating member frictionally charges the toner supplied from the supply roller to the developing roller at the nip portion between the toner layer regulating member and the developing roller. There is also a role.
[0005]
As the developer layer regulating member, a blade-like regulating blade is generally used. For example, when a so-called hard roller made of metal or resin is used as the developing roller, an elastic material such as urethane rubber is used as the regulating blade, and at least the surface portion of the developing roller is elastic like rubber. In the case of using a so-called soft roller having a metal blade, a metal blade or the like is used as the regulating blade.
[0006]
However, even if any of the regulating blades is used, since the regulating blade is brought into contact with and pressed against the developing roller, the surface of the regulating blade is worn over time, and it is difficult to extend the life of the regulating blade. In addition, the toner charged at the contact portion between the developing roller and the regulating blade is melted by frictional heat generated between the blade and the rotating developing roller, and a toner lump is easily generated at the contact portion. When a lump is formed, a streak-like mark is made on the toner, and when the solid portion is developed, white stripes are generated in the solid portion. In particular, when non-magnetic toner is used, the charging ability of the toner is deteriorated due to wear of the regulation blade, and the non-image portion is soiled due to insufficient charging of the toner, or the reproducibility of the minute dots is reduced. There was a problem to do.
[0007]
In view of this, a developing device that uses a roller-shaped regulating roller as a developer layer regulating member instead of the regulating blade has been proposed. However, with this restriction roller, in addition to the problem that the power consumption of the developing device increases, the size and cost of the device become difficult, and the fluctuation in the rotation speed of the developing roller increases, the developing roller There has been a problem in that the thickness of the toner layer formed thereon fluctuates and density unevenness occurs on the image.
[0008]
As a technique for solving this problem, a housing having a one-way clutch is provided at the end of a restriction roller (toner layer restriction doctor roller), and the rotation drive transmission to the developing device is reversely rotated so that the development roller is imaged. There has been proposed a developing device configured to drive the doctor roller by rotating it in the direction opposite to the rotating direction at that time (see Patent Document 1 below).
[0009]
The image forming apparatus disclosed in Patent Document 1 includes a latent image carrier and a developing device that develops a latent image on the latent image carrier, and the developing device includes the developer carrier and the developer carrier. In an image forming apparatus having a developer layer regulating roller that abuts against the time body and regulates the layer thickness of the developer carried on the developer carrying body, the developer carrying body is reverse to the rotation direction during development. A developer carrier reverse rotation driving means for rotating in the direction, and the developer layer regulating roller stops rotating at the time of development, and the developer carrier is reversely rotated by the reverse rotation driving means at the time of non-development. It is characterized by rotating and rotating. In this image forming apparatus, the rotation direction of the developer layer regulating roller is regulated by a one-way clutch.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-182470
According to this configuration, unlike the case where the regulating blade is used, the same surface is not always worn out, and the toner does not stay in the nip portion, so that the above problem is solved. The doctor roller is driven when the developing roller is reversely rotated at a time other than the time of image formation (the rotation direction at the time of image formation is the normal rotation direction), and is supplied from the supply roller onto the developing roller by the reverse rotation. Toner blowing from above the developing roller due to the thick toner layer, and abnormal images and background stains due to thin layer defects are prevented. Further, a toner storage chamber is formed in the developing device, and a predetermined amount of toner is supplied to the developing roller side based on a toner end signal on the developing roller side, so that the developing device causes the excessive amount of toner in the developing device. Preventing packing.
[0012]
However, in this developing device, when the toner is supplied from the toner storage chamber, the toner supply amount varies depending on the toner state on the developing roller side. In addition, the toner used up to the toner end undergoes considerable stress due to friction between the developing roller, the supply roller, and the toner layer regulating member due to scratching by the agitator, and the toner lump is likely to occur. It has become. Then, the toner block may be caught on the developing roller or the toner layer regulating member to form a white stripe or may be worm-eaten on the image.
[0013]
[Problems to be solved by the invention]
Accordingly, the first object of the present invention is to stop the agitator at a position away from the toner replenishing port leading from the toner storage chamber to the developing chamber at the time of toner end, and to smoothly supply the toner from the toner storing chamber to the developing chamber. An object of the present invention is to provide a developing device capable of preventing white stripes, insect erosion and the like.
A second object of the present invention is to realize a reduction in the size of the developing device and to suppress an increase in cost by making the toner end detection device also serve as an agitator position detection device.
[0014]
[Means for Solving the Problems]
The invention according to claim 1 includes a developing roller, a toner supply roller, a toner layer regulating member that regulates toner on the developing roller supplied by the toner supply roller to a thin layer having a predetermined layer thickness, and an agitator for toner conveyance. A developing chamber and a toner storage chamber having an agitator for conveying the toner. The toner storage chamber communicates with the developing chamber through a toner supply port, and the toner in the toner storage chamber is passed through the toner supply port by the agitator. The toner is conveyed to the developing chamber in the horizontal direction, and the toner in the developing chamber is further supplied to the developing roller via the toner supply roller by the agitator, and at a suitable position in the developing chamber above the toner supply port. deployed toner end detection device to the site, the position of the agitator body of those nearest to the toner replenishing port of the agitator deployed in the developing chamber Deployed agitator position detection equipment to output, nearest the agitator in the toner supply port is conveyed paddle, in close contact with the developing chamber wall, it has a function of stirring blade is the agitator body is rotated based on the toner end detection signal from the toner end detection device, the agitator position detector than said stirring blade of the toner supply port by stopping the lower position, forming a free space in the toner replenishing opening neighborhood portion of the developing chamber In this state, the developing device is characterized in that the toner in the toner storage chamber is conveyed and supplied to the developing chamber in the horizontal direction by the toner conveying agitator.
[0015]
The invention according to claim 2 is the developing device according to claim 1, wherein the toner end detection device also serves as an agitator position detection device.
[0016]
In the present invention , the agitator nearest to the toner replenishing port is a transport paddle, and the stirring blade, which is the main body of the agitator, stops at a predetermined position based on a detection signal from the agitator position detection device, thereby An empty space is formed in the vicinity of the toner supply port .
[0017]
According to a third aspect of the present invention, the toner replenishing port is a through hole formed in a partition member that partitions the developing chamber and the toner storage chamber, and the agitating blade of the transport paddle nearest to the toner replenishing port is from the toner replenishing port. The developing device according to claim 1 , wherein the empty space is formed by stopping at a lower position.
[0018]
According to a fourth aspect of the present invention, the developing device is detachably attached to the apparatus main body of the image forming apparatus independently. The image forming apparatus moves closer to a photosensitive member provided in the apparatus main body at the time of image formation. In this state, the developing roller is in contact with the photosensitive member or the developing roller is stopped at a minute interval with respect to the photosensitive member, and the toner is supplied from the developing roller to the photosensitive member. The developing device according to claim 1 , wherein when the image is not formed, an operation of separating from the photosensitive member is performed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing the structure of an image forming apparatus (color laser printer) to which a developing device according to the present invention is attached. FIG. 2 is a schematic sectional view showing the structure of the developing device. FIG. 3 is a cross-sectional view showing a state in the developing device shown in FIG. 4A is a front view of a drive gear for driving the first transport paddle constituting the developing device of FIG. 2, and FIG. 4B is an explanatory view showing the relationship between the drive gear and the mark detection unit. is there.
[0020]
The printer shown in FIG. 1 includes a photosensitive belt 1 as a latent image carrier that is wound around a plurality of support rollers. The photosensitive belt 1 is rotationally driven in a clockwise direction indicated by an arrow A in the drawing, and there are a charger 3, an optical writing unit 4, four sets of developing devices 5Bk, 5C, 5Y, and 5M, and an intermediate transfer member. An intermediate transfer belt 6 and a photoreceptor cleaning device 7 are arranged. An organic photosensitive layer is formed on the surface of the photoreceptor belt 1.
[0021]
The developing device 5Bk and the like are detachably attached to the printer main body independently. At the time of image formation, the developing devices 5Bk and the like move closer to the photosensitive belt 1 provided in the printer main body, thereby developing rollers 11Bk, 11C, and 11Y. , 11M come into contact with the photosensitive belt 1 or stop at a minute interval to supply toner to the photosensitive belt 1 from the developing roller. It is configured to perform an operation of separating from 1. In FIG. 1, reference numeral 10 (10Bk, 10M) is a developing container.
[0022]
When an image forming operation (printing operation) is executed by this printer, the photosensitive belt 1 is uniformly charged by applying a high voltage to the charger 3. In an image signal processing unit (not shown), color image information such as a color image signal sent from an external computer is converted into an optical writing signal and sent to the optical writing unit 4. In the optical writing unit 4, a laser as a light source (not shown) is controlled based on the optical writing signal, and Black (Bk) and Cyan (C) are passed through the polygon mirror 8, the f / θ lens 9a, and the reflecting mirror 9b. , Yellow (Y), and Magenta (M) image writing is performed, and an electrostatic latent image is formed on the photosensitive belt 1.
[0023]
The electrostatic latent image on the photosensitive belt 1 is subjected to each color by each of the developing devices 5Bk, 5C, 5M, and 5Y each having toner of each color as a developer charged with a charge having a polarity opposite to that of the latent image. Developed. As a result, a toner image is formed for each color on the photosensitive belt 1.
[0024]
At the contact portion between the photosensitive belt 1 and the intermediate transfer belt 6, the toner image on the photosensitive belt 1 is transferred onto the intermediate transfer belt 6 by applying a charge having a polarity opposite to that of the toner to the intermediate transfer belt 6. The By repeating this toner image formation and transfer operation four times, a four-color color toner image is formed on the intermediate transfer belt 6. The color toner image on the intermediate transfer belt 6 is transferred by a paper transfer roller 43 as a secondary transfer member to a transfer paper as a recording material sent from a paper feed cassette 40 or a manual feed tray 41 by a conveying roller pair 42. Is done. The transfer paper onto which the color toner image has been transferred is conveyed to a fixing unit comprising a fixing roller pair 44, and the toner image is melted and fixed.
[0025]
Next, the developing devices 5Bk, 5C, 5Y, and 5M according to the present embodiment will be described. As shown in FIG. 2, in the developing container 10 (for example, 10Bk, 10M in FIG. 1) constituting the developing device, the developing chamber 21 and the toner storage chamber 22 are partitioned by a plate-shaped partition member 31. The partition member 31 communicates through a toner supply port 32 that is a through hole formed in the center of the partition member 31.
[0026]
In the developing chamber 21, a developing roller 11, a toner supply roller 12, and a regulating roller (doctor as a toner layer regulating member for regulating the toner on the developing roller 11 supplied by the toner feeding roller 12 to a thin layer having a predetermined layer thickness) Roller) 14 and a first transport paddle 17a as a toner transport agitator. The first transport paddle 17 a is disposed in the vicinity of the toner supply port 32. In the toner storage chamber 22, a second transport paddle 17b and a third transport paddle 17c are provided as toner transport agitators.
[0027]
Further, in the developing chamber 21, a toner end detection device 71 is disposed above the toner supply port 32 of the partition member 31. The toner end detection device 71 also serves as an agitator position detection device. The toner end detection device 71 detects the position of the stirring blade of the first transport paddle 17a, and based on the toner end detection signal from the toner end detection device 71, the agitator position detection device By stopping the rotation of one transport paddle 17a and stopping the stirring blade at a predetermined position, that is, by stopping the stirring blade at a position lower than the toner supply port 32, a portion in the vicinity of the toner supply port 32 in the developing chamber 21. In this state, toner is transported and supplied from the toner storage chamber 22 to the developing chamber 21. If a plurality of transport paddles are provided in the developing chamber 21, the stirring blade closest to the toner supply port 32 among these transport paddles is stopped at a position below the toner supply port 32.
[0028]
Hereinafter, the developing device (such as 5Bk) according to the present embodiment will be described in more detail. This developing device is a one-component developing type developing device using non-magnetic one-component toner (hereinafter referred to as toner). Each developing device includes a developing container 10 having an opening toward the photosensitive belt 1, a developing roller 11 as a developer carrying member, and a toner supply roller 12 that supplies toner onto the developing roller 11. Further, each of the developing devices sends the toner stored in the first toner storage portion 18a, the second toner storage portion 18b, and the third toner storage portion 18c in the developing container 10 to the supply roller 12 side. 3 conveying paddles 17a to 17c, and a regulating roller as a developer layer regulating roller that contacts the developing roller 11 to regulate the layer thickness of the toner carried on the developing roller and forms a toner layer having a predetermined thickness 14 and so on.
[0029]
A part of the developing roller 11 is exposed from the opening of the developing container 10 and is installed so as to be rotatable in a clockwise direction indicated by an arrow at a predetermined linear speed at the time of development. The latent image formed on the photosensitive belt 1 is developed. The toner supply roller 12 is in contact with the developing roller 11 with a predetermined pressure, and the surface portion is made of polyurethane foam. Further, a toner regulating blade 13 is brought into contact with the toner supply roller 12 so that the amount of toner supplied to the developing roller 11 is regulated. Each of the transport paddles 17a to 17c is installed so as to be rotatable in the clockwise direction indicated by an arrow, and the toner is sent to the supply roller 12 side by this rotation. As a material of each transport paddle, for example, a soft and elastic material such as polypropylene can be used, and the toner is reliably transported by rotating in close contact with the inner wall of the developing container 10 using the elasticity.
[0030]
The regulating roller 14 regulates the toner on the developing roller 11 to a predetermined layer thickness, and frictionally charges the toner by making sliding contact with the toner. The toner charged on the developing roller 11 develops the electrostatic latent image on the photoreceptor belt 1. In the present embodiment, urethane rubber with resin coating is used as the material of the surface portion of the regulating roller 14. Further, a regulating roller cleaning blade 16 is in contact with the regulating roller 14 so that the surface of the regulating roller 14 that has passed through the contact portion with the developing roller 11 is cleaned.
[0031]
In the present embodiment, in order to absorb changes in the outer diameter of the developing roller 11 and the regulating roller 14 due to environmental fluctuations such as humidity, a spring 19 is provided as a biasing means for the regulating roller 14 to develop the regulating roller 14. Pressure is applied to the roller 11.
[0032]
Further, in the present embodiment, in order to prevent the toner from leaking out from the gap between the developing roller 11 and the developing container 10, an inlet that extends to the inner surface of the developing container 10 so that the tip is in contact with the surface of the developing roller 11. An artificial seal (not shown) is provided as a seal member.
[0033]
In FIG. 2, cams (not shown) that are independently rotatable are in contact with the side end portions of the developing devices (the right end portion of the developing container 10 in FIG. 2). 11 is separated from the photosensitive belt 1, while the developing roller 11 is moved to a developing position where it contacts the photosensitive belt 1 before the development. When the electrostatic latent image on the photosensitive belt 1 is developed, for example, when the Bk electrostatic latent image is formed on the photosensitive belt 1, the cam located at the rear portion of the developing device 5Bk The developing device 5Bk (that is, the developing container 10Bk) is pushed to the photosensitive belt 1 side by a drive control unit (not shown), and the developing roller 11Bk moves to a developing position where the developing roller 11Bk contacts the photosensitive belt 1. The same applies to the developing devices 5C, 5Y, 5M of other colors.
[0034]
The image forming mechanism by the developing device will be further described. The toner is transported to the toner supply roller 12 by the first transport paddle 17a, and then supplied from the supply roller 12 to the developing roller 11. The toner supplied to the developing roller 11 is charged and thinned by a regulating roller (doctor roller) 14, and the electrostatic latent image formed on the photosensitive belt 1 is developed and visualized.
[0035]
Toner is supplied from the toner storage chamber 22 to the developing chamber 21 through a toner replenishing port 32 that is an opening formed in a substantially central portion of the partition member 31. The developing chamber 21 is provided with a toner end detecting device 71. When a sufficient amount of toner is stored in the developing chamber 21, the amount of toner supplied from the toner storage chamber 22 to the developing chamber 21 is almost the same. Zero. Further, when the remaining amount of toner in the developing chamber 21 becomes equal to or less than a predetermined value, toner supply from the toner storage chamber 22 to the developing chamber 21 is performed for a specified time by an end detection signal of the toner end detection device 71.
[0036]
Various methods for supplying toner from the toner storage chamber 22 to the developing chamber 21 can be employed. For example, (1) a shutter mechanism is added to the toner replenishing port 32, and when there is a sufficient amount of toner in the developing chamber 21, the shutter is closed and the remaining amount of toner in the developing chamber 21 has become a predetermined value or less. At this time, the shutter is opened by the end detection signal to perform a toner supply operation, or (2) when there is a sufficient amount of toner in the developing chamber 21, the second and third transport paddles 17b and 17c are rotated. Stop (however, the first conveyance paddle 17a remains rotated), and when the remaining amount of toner in the developing chamber 21 becomes a predetermined value or less, the second and third are detected based on the end detection signal. It is possible to perform a toner supply operation by rotating the transport paddle.
[0037]
The toner end detecting device 71 has a structure in which lenses (not shown) are provided on one side and the other side in the longitudinal direction of the developing device, light is incident through one lens, and light is incident through the other lens. One that detects light by a light receiving sensor and detects the end based on the output of the light receiving sensor, or one that detects by unit torque (when there is a sufficient amount of toner in the developing chamber 21, the torque of the transport paddle increases), A device that detects the pressure during cleaning of the transport paddle with a piezoelectric sensor can be used. In the case of the above light receiving sensor, when the conveyance paddle cleans the lens, the signal level of the light receiving sensor decreases (the signal level decreases as the amount of received light increases), and the end can be detected by the number of times the threshold level is cut.
[0038]
The toner in the developing chamber 21 is considerably stressed when it approaches the toner end due to stress due to rotation of the first transport paddle 17a and stress due to friction with the developing roller 11, the toner supply roller 12, and the regulating roller 14. Since the fluidity is reduced due to accumulation, toner aggregates are easily generated. Since this toner aggregate may be sandwiched between the developing roller 11 and the regulating roller 14 to form white stripes, or the transferability may change on the image and become worm-eaten, the following means are used in the present invention. I try to give it.
[0039]
FIG. 3 is a cross-sectional view showing a state inside the developing device at the time of toner end. When the first transport paddle 17a is below the toner replenishing port 32, that is, in the range of the position indicated by reference numeral 51 (horizontal broken line) to the position indicated by reference numeral 52 (vertical broken line) in FIG. As a result of the toner being brought close to the developing roller 11 and an empty space (a space having a low toner density) being formed in front of the toner replenishing port 32 of the developing chamber 21, toner supply from the toner storage chamber 22 to the developing chamber 21 is efficiently performed. Done.
[0040]
FIG. 4 relates to a means for detecting the rotational position of the stirring blade, which is the main body of the first transport paddle 17a, and FIG. 4 (a) is a front view of a drive gear 60 for driving the first transport paddle 17a. FIG. 4B is a diagram for explaining the relationship between the drive gear 60 and the mark detection unit 70. The mark detection unit 70 constitutes an agitator position detection device for detecting the rotational position of the stirring blade. The gear 60 is marked with a mark 61 whose positional relationship with the first transport paddle 17a is determined.
[0041]
Based on the toner end detection signal from the toner end detection device 71, the agitator position detection device stops the stirring blades of the first transport paddle 17 a in the space between the reference numerals 51 and 52. In this way, an empty space is formed near the toner supply port 32 in the developing chamber 21. In this case, the mark detection unit 70 in which the positional relationship with the space between the reference numerals 51 and 52 is determined performs the mark 61 detection operation, and when this is detected, the rotation of the first transport paddle 17a is stopped, The stirring blade is stopped in the space between reference numerals 51 and 52. Further, the stirring blades of the first transport paddle 17a can be stopped in the space also by the end detection signal of the toner end detection device 71 whose positional relationship with the space is determined in advance. The rotation of the first transport paddle 17a can be stopped by a clutch or the like.
[0042]
【The invention's effect】
As is apparent from the above description, the developing device according to the first to fourth aspects of the present invention includes a toner end detecting device at an appropriate position in the developing chamber, and an agitator closest to the toner supply port among the agitators disposed in the developing chamber. An agitator position detection device that detects the position of the main body is deployed, and based on the toner end detection signal from the toner end detection device, the agitator position detection device stops the agitator main body of the nearest agitator at a predetermined position, thereby developing. An empty space is formed near the toner replenishing port in the room, and in this state, the toner in the toner storage chamber is transported and supplied to the development chamber by the toner transport agitator. The toner can be smoothly and efficiently supplied to the developing chamber, and the fluidity of the toner is reduced. It is not possible to, white streaks and the occurrence of worm-eaten on the image can be prevented appropriately.
[0043]
In particular, in the developing device according to the second aspect of the invention, since the toner end detecting device also serves as the agitator position detecting device, the number of parts can be reduced, and the cost increase and the miniaturization of the developing device can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing the structure of an image forming apparatus (color laser printer) to which a developing device according to the present invention is attached.
FIG. 2 is a schematic cross-sectional view showing a structure of a developing device according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a state in the developing device shown in FIG. 2 at the time of toner end.
4A is a front view of a first transport paddle driving gear provided in the developing device of FIG. 2, and FIG. 4B is an explanatory diagram showing a relationship between the driving gear and a mark detection unit.
[Explanation of symbols]
1: Photoconductor belt 3: Charger 4: Optical writing unit 5Bk, 5C, 5Y, 5M: Developing device 6: Intermediate transfer belt 7: Photoconductor cleaning devices 10, 10Bk, 10M: Developer containers 11, 11Bk, 11C, 11Y , 11M: developing roller 12: toner supply roller 13: toner regulating blade 14: regulating roller (doctor roller)
16: restriction roller cleaning blade 17a: first transport paddle 17b: second transport paddle 17c: third transport paddle 18a: first toner storage unit 18b: second toner storage unit 18c: third toner storage unit 19: spring 21: Developing chamber 22: Toner storage chamber 31: Partition member 32: Toner replenishment port 51: Position 52: Position 60: Drive gear 61: Mark 70: Mark detector 71: Toner end detector

Claims (4)

A developing chamber having a developing roller, a toner supply roller, a toner layer regulating member for regulating the toner on the developing roller supplied by the toner supply roller to a thin layer having a predetermined thickness, and an agitator for toner conveyance;
A toner storage chamber equipped with an agitator for toner conveyance,
The toner storage chamber communicates with the developing chamber via the toner supply port,
The toner in the toner storage chamber is conveyed by the agitator to the developing chamber in the horizontal direction via the toner replenishing port, and the toner in the developing chamber is further supplied to the developing roller via the toner supply roller by the agitator. With
A toner end detection device is provided at an appropriate position in the developing chamber and above the toner supply port ,
The agitator position detection equipment for detecting the position of the agitator body of those nearest to the toner replenishing port of the agitator deployed in the developing chamber deployed,
The agitator nearest to the toner replenishing port is a transport paddle, and has a function of rotating the stirring blade that is the main body of the agitator while in close contact with the wall of the developing chamber.
Based on the toner end detection signal from the toner end detection device, the agitator position detection device stops the stirring blade at a position below the toner supply port, thereby forming an empty space near the toner supply port in the developing chamber. ,
In this state, a developing device characterized in that the toner in the toner storage chamber is transported and supplied to the developing chamber in the horizontal direction by the toner transport agitator.   The developing device according to claim 1, wherein the toner end detection device also serves as an agitator position detection device. The toner replenishing port is a developing device according to claim 1 or 2, characterized in through holes der Rukoto formed in the partition member to define a developing chamber and a toner storage chamber. The developing device is detachably attached to the main body of the image forming apparatus independently.
At the time of image formation, the developing roller comes into contact with the photosensitive member by moving closer to the photosensitive member arranged in the apparatus main body, or the developing roller is stopped at a minute interval with respect to the photosensitive member. , Respectively, to supply toner from the developing roller to the photoreceptor,
4. The developing device according to claim 1 , wherein when the image is not formed, an operation of separating the photosensitive member from the photosensitive member is performed. 5.

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