JP2001117345A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely eliminate toner from the sensor surface of a toner detector and to surely detect the supply time of the toner without causing any malfunction in an image forming device and the like using plural developing units different in attitude. SOLUTION: This developing device 1 is constituted so that an electrostatic latent image formed at a latent image carrier 140 is developed with dry type developer supplied to the electrostatic latent image from the developing unit 10. Besides, it is constituted so that the plural developing units 10M and 10C whose postures are different are arranged upward and downward in parallel. The respective developing units are provided with developer supply time detection means 21M and 21C detecting the supply time of the developer and wipe means 24 periodically wiping the detection surfaces of the detection means 21M and 21C. Then, the structure of the units 10M and 10C neat the detection means 21M and 21C are made different according to the postures thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copier, a facsimile or a printer, and more particularly to a developing apparatus using a plurality of developing units having different postures.

[0002]

2. Description of the Related Art Conventionally, as a method of arranging developing units in an electrophotographic color image forming apparatus, four developing units corresponding to four colors are arranged rotatably in a rotary manner with respect to a photosensitive member. A type in which the rotary is rotated to bring the developing units of each color into contact with the photoconductor in order (for example, Japanese Patent Application Laid-Open No. 7-27121).
No. 0) and a type in which the same four developing units having the same posture are arranged in parallel with respect to a photosensitive body that moves linearly, and the developing units of each color are sequentially brought into contact with the photosensitive body (for example, Japanese Patent Laid-Open No. 10-1489).
No. 89) is known.

When a high-speed and small-sized color image forming apparatus is constructed using such a developing device, it is difficult to switch the developing device at a high speed in the case of a type in which a rotary is rotated. In the case of a type in which four developing units having the same attitude are arranged in parallel, there is a problem that the apparatus becomes large.

In view of this, for example, a type in which a plurality of color developing units having different postures are vertically arranged around a drum-shaped photoreceptor and are brought into contact with the photoreceptor in order is considered.

Although not related to a color image forming apparatus using a plurality of developing units, in a dry developing unit of an electrophotographic image forming apparatus, the timing of replenishing toner by detecting the level of the toner in the developing unit. When installing a toner detector that detects toner, a member that stirs and scrapes the toner near the sensor surface to prevent the toner from solidifying on the sensor surface of the toner detector and causing a malfunction may not be provided. And JP-A-62-56974.

[0006]

In a developing apparatus having a plurality of developing units having different postures arranged in parallel one above the other as described above, when a toner detector is installed in each developing unit, a sensor of the toner detector is used. In order to prevent the toner from solidifying on the surface and causing a malfunction, it is necessary to provide some means for scraping the toner from the sensor surface. However, since the attitude of each developing device is different, a scraping means corresponding to the attitude is required.

SUMMARY OF THE INVENTION The present invention has been made in response to the above circumstances, and has as its object to provide a small and high-speed color image forming apparatus using a plurality of developing units having different postures.
An object of the present invention is to reliably wipe off toner from a sensor surface of a toner detector and to reliably detect toner replenishment timing without malfunction.

[0008]

According to the present invention, there is provided a developing device for developing an electrostatic latent image formed on a latent image carrier with a dry developer supplied from a developing device. In a developing device in which a plurality of developing devices having different postures are vertically arranged in parallel, each of the developing devices includes a developer replenishing time detecting means for detecting a replenishing time of the developer and a detecting means for detecting the developer replenishing time detecting means. Wiping means for periodically wiping the surface, wherein the structure of the developing device in the vicinity of the developer replenishment timing detecting means is different depending on the attitude of the developing device.

In this case, each developing device has on its shaft a developer replenishing time detecting means for detecting the replenishing time of the developer and a wiping means for periodically wiping the detecting surface of the developer replenishing time detecting means. A first agitator chamber having a first agitator, and a developing chamber rotatably supporting the developer carrier.
A second agitator chamber having a second agitator disposed between the first agitator chamber and the developing chamber, wherein a second agitator chamber has a second agitator chamber and a second agitator chamber. The structure of the developing device in the vicinity of the developer replenishment timing detecting means can be different.

In this case, it is desirable that the wiping direction of the wiping means be the same as the rotation direction of the first agitator.

Further, in a developing device in which the rotation center of the first agitator is located above the rotation center of the second agitator in the direction of gravity, the developer water level decreases in the direction opposite to the developer replenishment timing detecting means of the wiping means. It is desirable to provide prevention means.

In this case, it is desirable that the width of the developer water level lowering prevention means and the width of the wiping means be substantially the same.

Further, it is desirable to provide developer conveying means on both sides of a portion of the second agitator corresponding to the means for preventing the developer water level from dropping.

In the present invention, each developing device has a developer replenishing time detecting means for detecting a replenishing time of the developer, and a wiping means for periodically wiping a detection surface of the developer replenishing time detecting means. Since the structure of the developing device in the vicinity of the developer replenishing timing detecting means is made different depending on the attitude of the developing device, the developer replenishing timing detecting means is different in any developing device even if the attitude of the developing device is different. There is no micro gradient in the water level of the developer near the water level detection surface, and the developer replenishment timing detecting means can accurately detect the level of the developer, and the developer replenishment timing can be reliably detected without malfunction. it can.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of an example of an image forming apparatus to which a developing device of the present invention is applied will be described with reference to FIG.

This image forming apparatus is capable of forming a full-color image using a developing device using four color toners of yellow (Y), magenta (M), shiashi (C) and black (K). It is a printer.

In FIG. 1, reference numeral 100 denotes an image carrier cartridge in which an image carrier unit is incorporated. In this example, the image carrier cartridge is constituted as a photoconductor cartridge, and a photoconductor (latent image carrier) 140 is not shown. It is rotationally driven in a direction indicated by an arrow by an appropriate driving means. Photoconductor 140
Has a thin cylindrical conductive substrate and a photosensitive layer formed on the surface thereof.

Around the photoreceptor 140, a charging roller 160 as a charging means, an exposure unit 40, and a developing device 10 (Y, M,
C, K), the intermediate transfer device 30, and the cleaning unit 170 are arranged.

The charging roller 160 contacts the outer peripheral surface of the photoconductor 140 to uniformly charge the outer peripheral surface. On the outer peripheral surface of the uniformly charged photoconductor 140, a selective exposure L1 according to desired image information is performed by the exposure unit 40,
By the exposure L1, an electrostatic latent image is formed on the photoconductor 140.

The electrostatic latent image is developed with, for example, a one-component non-magnetic toner by the developing device 1. As a developing device of the developing device 1, a developing device 10Y for yellow, a developing device 10M for magenta, a developing device 10C for cyan, and a developing device 10K for black are vertically arranged on the outer peripheral surface of the photoconductor 140 in different postures. They are arranged in parallel. And each developing device 1
The toner cartridges 20Y, 20M, 20C, and 20K are mounted on 0Y, 10M, 10C, and 10K, and toners (developers) of the respective colors are developed by the developing devices 10Y, 10M, and 1K.
It is designed to be replenished to 0C and 10K. Each of the developing devices 10Y, 10M, 10C, and 10K is configured to be swingable, so that only the developing roller 11 of one developing device can selectively contact the photoconductor 140. Therefore, these developing devices 10 apply any one of yellow, magenta, cyan, and black toners to the surface of the photoconductor 140 to develop the electrostatic latent image on the photoconductor 140. The developing roller 11 is formed of a hard roller, for example, a metal roller having a roughened surface, or a hard resin roller.

The developed toner image is transferred onto an intermediate transfer belt 36 of an intermediate transfer device.

The cleaning means 170 includes a cleaner blade for scraping off the toner remaining on and adhering to the outer peripheral surface of the photoreceptor 140 after the transfer, and a receiving portion for receiving the toner scraped off by the cleaner blade. I have.

The intermediate transfer device 30 includes a driving roller 31,
Four driven rollers 32, 33, 34, 35 and an endless intermediate transfer belt 36 stretched around these rollers.
And

The drive roller 31 is driven to rotate at substantially the same peripheral speed as the photosensitive member 140 because a gear (not shown) fixed to an end of the drive roller 31 meshes with a drive gear for the photosensitive member 140. The transfer belt 36 is driven to circulate at substantially the same peripheral speed as the photosensitive member 140 in the direction of the arrow shown in the figure.

The driven roller 35 is disposed at a position where the intermediate transfer belt 36 is pressed against the photosensitive member 140 by its own tension with the driving roller 31.
A primary transfer portion T1 is formed at a pressure contact portion between the intermediate transfer belt 36 and the intermediate transfer belt 36. The driven roller 35 is disposed near the primary transfer portion T1 on the upstream side in the circulation direction of the intermediate transfer belt 36.

The driving roller 31 has an intermediate transfer belt 36
A primary transfer voltage is applied to the conductive layer of the intermediate transfer belt 36 via the electrode roller (not shown).

The driven roller 32 is a tension roller, and urges the intermediate transfer belt 36 in the tension direction by an urging means (not shown).

The driven roller 33 is a backup roller that forms the secondary transfer portion T2. A secondary transfer roller 38 is opposed to the backup roller 33 via an intermediate transfer belt 36. The secondary transfer roller 38
It can be moved toward and away from the intermediate transfer belt 36 by a contacting / separating mechanism (not shown). A secondary transfer voltage is applied to the secondary transfer roller 38.

The driven roller 34 is a backup roller for the belt cleaner 39. Belt cleaner 39
Is a cleaner blade 39 which comes into contact with the intermediate transfer belt 36 and scrapes off the toner remaining and adhering to the outer peripheral surface thereof.
a, and a receiving portion 39b for receiving the toner scraped off by the cleaner blade 39a. The belt cleaner 39 can be moved toward and away from the intermediate transfer belt 36 by a contact / separation mechanism (not shown).

In the process of circulating the intermediate transfer belt 36, the toner image on the photosensitive member 140 is transferred onto the intermediate transfer belt 36 in the primary transfer portion T1, and the toner image transferred onto the intermediate transfer belt 36 is Is transferred to a sheet (recording material) S, such as a sheet, supplied between the secondary transfer roller 38 and the secondary transfer unit T2.

The sheet S is fed from the sheet feeding device 50,
The toner is supplied to the secondary transfer station T2 at a predetermined timing by the gate roller pair G. 51 is a paper feed cassette, and 52 is a pickup roller.

The sheet S, to which the toner image has been transferred in the secondary transfer portion T2, is fixed on the sheet S by passing through a fixing device 60, and is formed on a case 80 of the apparatus main body through a sheet discharge path 70. The sheet is discharged onto the received sheet receiving portion 81. In this image forming apparatus, as a paper discharge path 70,
It has two paper discharge paths 71 and 72 independent of each other, and the sheet that has passed through the fixing device 60 is discharged through one of the paper discharge paths (71 or 72). The paper discharge paths 71 and 72 also constitute a switchback path. When an image is formed on both sides of the sheet, the sheet once entering the paper discharge path 71 or 72 passes through the return path 73. Then, the sheet is fed again to the secondary transfer portion T2.

With such a configuration, the entire image forming apparatus operates in the following order.

When a drawing command signal (image forming signal) from a not-shown host computer or the like (a personal computer or the like) is input to the control unit 90 of the image forming apparatus, the photosensitive member 140, each roller 11 of the developing device 10, and , The intermediate transfer belt 36 is driven to rotate.

The outer peripheral surface of the photosensitive member 140 is
Is charged uniformly. Photoreceptor 14 uniformly charged
On the outer peripheral surface of 0, selective exposure L1 is performed by the exposure unit 40 according to the image information of the first color (for example, yellow), and an electrostatic latent image for yellow is formed.

Only the developing roller of the developing device 10Y for the first color (for example, yellow) comes into contact with the photosensitive member 140, whereby the electrostatic latent image is developed, and the toner image for the first color (for example, yellow) is developed. Is formed on the photoconductor 140.

A primary transfer voltage having a polarity opposite to that of the toner is applied to the intermediate transfer belt 36.
The toner image formed thereon is transferred onto the intermediate transfer belt 36 at the primary transfer portion T1. At this time, the secondary transfer roller 38 and the belt cleaner 39 are separated from the intermediate transfer belt 36.

After the toner remaining on the photoreceptor 140 is removed by the cleaning means 170, the photoreceptor 140 is discharged by the discharging light from the discharging means (not shown).

The above operation is repeated for the second color plane, the third color plane, and the fourth color plane according to the contents of the drawing command signal, and the toner image corresponding to the contents of the drawing command signal is transferred to the intermediate transfer belt. The intermediate transfer belt 36 is formed on the intermediate transfer belt 36 by being superposed on the intermediate transfer belt 36.

The sheet S is supplied from the sheet feeding device 50 at a predetermined timing, and immediately before or after the leading end of the sheet S reaches the secondary transfer portion T2 (that is, the intermediate transfer is performed at a desired position on the sheet S at a desired position). At the timing when the toner image on the belt 36 is transferred, the secondary transfer roller 38 is pressed against the intermediate transfer belt 36 and a secondary transfer voltage is applied, and the toner image on the intermediate transfer belt 36 (basically, A full-color image in which four color toner images are superimposed) is transferred onto the sheet S. Further, the belt cleaner 39 contacts the intermediate transfer belt 36, and after the secondary transfer, the intermediate transfer belt 3
6 is removed.

The toner image is fixed on the sheet S by passing the sheet S through the fixing device 60, and thereafter, the sheet S is directed to a predetermined position (or the sheet receiving section 81 in the case of non-double-sided printing. In the case of (1), the sheet is conveyed via the switchback path 71 or 72 to the return path 73).

Incidentally, as is apparent from FIG. 1, the four developing units 10Y, 10M, 10
C and 10K are vertically arranged side by side in different postures with respect to the outer peripheral surface of the photoconductor 140. The developing units 10Y and 10M are arranged downward, and the developing units 10C and 10K are arranged upward. Therefore, the developing device 1 for magenta
FIG. 2 is an enlarged view showing 0M as a representative of the downward developing device and 10C of the cyan developing device as a representative of the upward developing device. Here, the distinction between downward and upward will be described later.

In FIG. 2, both developing units 10M and 10C
Are composed of basic constituent members having the same function, and will be described by omitting M and C after the numerals indicating the respective members for the time being. However, as shown in FIG. 2, the members forming the developing units 10M and 10C "M" and "C" are added after the number to distinguish them.

Each developing unit includes a developing chamber 14, a first agitator chamber 18, a second agitator chamber 19, and a toner cartridge 20 (FIG. 1). Body) 11, a supply roller (developer supply body) 12 for supplying a developer (toner) to the surface of the developing roller 11, and a regulating member 13 for regulating the thickness of the toner layer carried on the surface of the developing roller 11. The developing bias voltage is applied to the developing roller 11, the supply bias voltage is applied to the supply roller 12, and the toner that is frictionally charged by the rotation of the supply roller 12. Is the supply roller 12 to the developing roller 11
The thickness of the toner layer carried on the surface of the developing roller 11 is regulated by the regulating member 13, and the toner carried on the surface of the developing roller 11 is subjected to further triboelectric charging.

A first agitator 16 for stirring the toner supplied from the toner cartridge 20 through the toner supply port 22 to maintain a high fluidity state is disposed in the first agitator chamber 18. In the agitator chamber 19, a second agitator 17 for stirring the toner conveyed from the first agitator chamber 18 and keeping the toner in a high fluidity state is disposed, and the toner is transferred to the developing chamber 14 while maintaining the fluidity of the toner. And convey.

A partition wall 23 is provided between the second agitator chamber 19 and the developing chamber 14 to divide the two chambers from below to some extent, and only the toner that has passed over the upper side is transported from the second agitator chamber 19 to the developing chamber 14. Is done.

In the first agitator chamber 18, a toner detector 21 composed of a piezoelectric element or the like is disposed below the toner supply port 22.
The toner level is detected, and the timing of replacing the toner cartridge 20 via the toner supply port 22 to supply toner is detected.

As is apparent from FIG. 2, the developing unit 10M disposed upstream of the photosensitive member 140 is provided with the first agitator 1
The rotation center of 6M is higher in the vertical direction than the rotation center of the second agitator 17M, and the developing unit 10C arranged downstream of the photoreceptor 140 has the rotation center of the first agitator 16C in the second direction.
It is lower in the vertical direction than the rotation center of the agitator 17C. As described above, the developing unit 10M whose rotation center of the first agitator 16M is higher than the rotation center of the second agitator 17M faces downward, and the rotation center of the first agitator 16C is lower than the rotation center of the second agitator 17C. The developing device 10C is an upward developing device.

In the present invention, in both the downward developing device 10M and the upward developing device 10C, the toner detector 21M in front of the toner detectors 21M and 21C is used.
M, the first agitator 16 corresponding to the width of 21C
A fin-shaped wiping member 24 for wiping the vicinity of the sensor surfaces of the toner detectors 21M and 21C with the rotation of the first agitators 16M and 16C in the arrow direction is attached to M and 16C. 3 and 4 show the first agitator 16M of the downward developing device 10M and the upward developing device 10C, respectively.
FIG. 13 is a plan view of the first agitator 16C of FIG.
Two fin-shaped wiping members 24 are attached at an interval of 80 ° by bonding or welding with a double-sided adhesive tape 26. As shown in FIG. 4, two fin-shaped toner conveying members 25 are similarly provided around the axis of the first agitator 16C of the upward developing device 10C at intervals 29 on both sides of the wiping member 24. Double-sided adhesive tape 27
It is attached by bonding or welding.

With such a configuration, the wiping member 24
Rotates with the rotation of the first agitators 16M and 16C, and wipes the sensor surfaces of the toner detectors 21M and 21C every half rotation. Therefore, the toner detectors 21M, 21M
The toner level in the vicinity of the 1C sensor surface has no micro gradient, and the toner level can be accurately detected by the toner detectors 21M and 21C.

However, especially in the downward developing device 10M, there is a slight problem by itself. In a downward developing device such as the developing device 10M, the toner moves from the first agitator chamber 18M to the second agitator chamber 19M by gravity.
Further, it is transported to the developing chamber 14M. In addition, when the fin-shaped wiping member 24 rotates, the wiping member 24 acts as a unit for transporting the toner to the second agitator chamber 19M at that portion (the portion of the toner detector 21M), and the portion of the toner detector 21M is formed. In such a case, the water level of the toner drops earlier than in other parts. Therefore, the developing device 10
Although a large amount of toner still remains in M,
There is a possibility that the toner detector 21M may erroneously detect the toner supply timing. In such a case, if the toner cartridge is replaced with a new toner cartridge 20M, the toner is excessively filled and the weight of the developing device 10M becomes heavier than a prescribed weight, so that the mechanism of separating and connecting the developing device 10M to the photoconductor 140 causes a failure. It causes the trouble such as.

Therefore, in the downward developing device 10M, the first portion of the portion to which the fin-shaped
Between the agitator chamber 18M and the second agitator chamber 19M,
As shown in the plan view of FIG. 5 and FIG. 2, a toner water level lowering prevention means 28 composed of a wall is provided. When such a wall 28 is provided, the wiping member 24 transfers the toner to the second agitator chamber 1.
Even if an action is taken to convey the toner to 9M, the toner conveying action is prevented by the wall 28.

Accordingly, the means 28 for preventing toner water level from dropping
The toner is agitated by the wiping member 24 between the first agitator chamber 18M and the toner detector 21M to reflect the water level of the toner in the entire first agitator chamber 18M. For example, the toner detector 21M
When the water level of the toner in the first agitator chamber 18M on both sides of the portion is lowered, the toner pressed against the wall 28 by the wiping member 24 is pushed out to both sides as a flow shown by a thick arrow in FIG. The water level of the toner at the detector 21M also drops.

Accordingly, in the downward developing device 10M, the first developing device 10M driven to rotate in front of the toner detector 21M is used.
The interaction between the wiping member 24 attached to the agitator 16M and the toner water level lowering prevention means 28 provided on the front side opposite to the toner detector 21M makes it possible to accurately detect the toner water level, and to supply toner. The timing can be reliably detected without malfunction.

In the case of the upward developing device 10C, since the second agitator chamber 19C is higher than the first agitator chamber 18C, the wiping member 24 detects the toner by the toner detector 21C.
Even when the toner is conveyed to the second agitator chamber 19C at the portion C, the toner is again returned to the first agitator chamber 18 by the action of gravity.
C, the water level of the toner detected by the toner detector 21C becomes the same as the toner level of the entire first agitator chamber 18C without providing the toner water level lowering prevention means. Can be accurately detected, and the toner supply timing can be reliably detected without malfunction.

In the case of the upward developing device 10C, as shown in FIG. 4, a fin-shaped toner conveying member 25 is attached to both sides of the wiping member 24 of the first agitator 16C with a space 29 therebetween. This toner conveying member 2
By the operation of 5, the toner in the first agitator chamber 18C is forcibly conveyed to the second agitator chamber 19C against gravity. Therefore, the water level of the toner at the position of the first agitator chamber 18C corresponding to the wiping member 24 may drop earlier than the other parts due to the effect of the operation of the toner conveying member 25.
A certain distance 2 between the mounting range of the toner conveying member 25 and the mounting range of the wiping member 24 of the agitator 16C.
It is desirable to provide 9 to prevent such an effect.

The width (the first agitator 16) of the wall 28 of the toner level lowering prevention means in the downward developing unit 10M
Regarding the relationship between the width of the wiping member 24 and the width of the wiping member 24, when the width of the wiping member 24 is larger, the water level of the toner decreases more rapidly than in other parts. If the width of 24 is smaller, even if the water level of the toner in the entire first agitator chamber 18M lowers, it becomes difficult for the toner to flow laterally from the front part of the toner detector 21M, and the lowering of the water level of the toner to other parts. In comparison, it is slower and neither is preferred. Therefore, it is desirable that the width of the water level lowering prevention means 28 and the width of the wiping member 24 be substantially the same (FIG. 5).

Next, in the downward developing device 10M arranged as shown in FIG. 5, the toner conveying members 25 such as the agitators 16C and 17C of the upward developing device 10C are not attached to the agitators 16M and 17M, and the replenishment is performed. The discharged toner is conveyed from the first agitator chamber 18M to the second agitator chamber 19M and further to the developing chamber 14M by the action of gravity, so that toner (blocking toner) staying without touching the agitators 16M and 17M is generated. Cheap.
In particular, such blocking toner is easily generated between the first agitator chamber 18M and the second agitator chamber 19M on both sides of the water level lowering prevention means 28, and when the blocking toner collapses, the toner detector 21 located in the vicinity thereof
M may erroneously detect the toner supply timing.

Therefore, as shown in FIG. 6, a fin-shaped member 200 having a function of transporting toner is wiped on both sides of a portion of the second agitator 17M corresponding to the wall 28 of the toner water level lowering prevention means by the wiping member 24. Alternatively, the toner conveying member 25
Attach it as above. After the developing chamber 14 on the front side of the second agitator chamber 19M is full of toner, the member 200 transfers the toner from the developing chamber 14 to the first agitator chamber 1M.
It acts as a toner transport member to be brought back in the 8M direction. Therefore, the first agitator chamber 18M and the second agitator chamber 1
9M, the gravity moves from the first agitator chamber 18M to the second agitator chamber 19M by gravity, and vice versa.
0, the second agitator chamber 19M moves to the first agitator chamber 18 as shown by the thick arrow in FIG.
The exchange of toner to M becomes active, and the occurrence of the blocking toner described above can be prevented, and erroneous detection of the toner supply timing of the toner detector 21M that occurs when the blocking toner collapses can be prevented.

Although the developing device of the present invention has been described based on the embodiments, the present invention is not limited to these embodiments, and various modifications are possible.

[0061]

As is apparent from the above description, according to the developing device of the present invention, each developing unit detects the developer replenishment timing by detecting the replenishment timing of the developer and the detection by the developer replenishment timing detector. Wiping means for periodically wiping the surface, and the structure of the developing device in the vicinity of the developer replenishment timing detecting device is made different depending on the posture of the developing device. Also in the developing device, there is no micro gradient in the developer water level near the developer water level detection surface of the developer replenishment timing detecting means, and the developer replenishment timing detecting means can accurately detect the developer water level. In addition, the developer supply timing can be reliably detected without malfunction.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an example of an image forming apparatus to which a developing device of the present invention is applied.

FIG. 2 is an enlarged sectional view showing both a downward developing device and a downward developing device according to an embodiment of the present invention.

FIG. 3 is a plan view of a first agitator of the developing device facing downward in FIG. 2;

FIG. 4 is a plan view of a first agitator of the upward developing device in FIG. 2;

FIG. 5 is a plan view of the main part of the downwardly directed developing device in FIG. 2 with a cover removed.

FIG. 6 is a plan view of a modification example of the present invention in which a cover of a main part of a downward developing device is removed.

[Explanation of symbols]

Reference Signs List 1 developing device 10 developing device 10Y yellow developing device (Y developing unit) 10M magenta developing device (M developing unit) 10C cyan developing device (C developing unit) 10K black developing device (K developing Unit) 11, 11M, 11C Developing roller (developer carrier) 12, 12M, 12C Supply roller (developer supplier) 13, 13M, 13C Control member 14, 14M, 14C Developing chamber 16, 16M 16C: first agitator 17, 17M, 17C: second agitator 18, 18M, 18C: first agitator chamber 19, 19M, 19C: second agitator chamber 20, 20Y, 20M, 20C, 20K: toner cartridge 21, 21M, 21C: toner detector 22, 22M, 22C: toner supply port 23, 23M, 23C: partition 24: Wiping member 25: Toner transport member 26: Double-sided adhesive tape 27: Double-sided adhesive tape 28: Toner water level lowering prevention means 29: Interval 30: Intermediate transfer device 31: Driving rollers 32, 33, 34, 35: Follower roller 36 ... intermediate transfer belt 38 ... secondary transfer roller 39 ... belt cleaner 39a ... cleaner blade 39b ... receiving part 40 ... exposure unit 50 ... paper feeder 51 ... paper feed cassette 52 ... pickup roller 60 ... fixing devices 70, 71, 72 ... Paper discharge path 73 Return path 80 Case 81 Sheet receiving section 90 Control section 100 Image carrier cartridge 140 Photoconductor 160 Charging roller 170 Cleaning means 200 Toner conveying member L1 Exposure light T1 Primary transfer Section T2: Secondary transfer section S: Sheet (recording material) G: Gate roller pair

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Claims (6)

[Claims] 1. A developing device for developing an electrostatic latent image formed on a latent image carrier with a dry developer supplied from a developing device, wherein a plurality of developing devices having different postures are vertically arranged in parallel. In the developing device, each of the developing devices includes a developer replenishing time detecting means for detecting a replenishing time of the developer, and a wiping means for periodically wiping a detection surface of the developer replenishing time detecting means. A developing device, wherein the structure of the developing device in the vicinity of the agent supply timing detecting means has a different structure depending on the attitude of the developing device. 2. Each developing device has, on its shaft, a developer replenishing time detecting means for detecting a replenishing time of the developer and a wiping means for periodically wiping a detection surface of the developer replenishing time detecting means. A first agitator chamber having a first agitator, a developing chamber rotatably supporting a developer carrier, a second agitator chamber disposed between the first agitator chamber and the developing chamber and having a second agitator; Wherein the structure of the developing device in the vicinity of the developer replenishment timing detecting means is different depending on the vertical relationship between the rotation center of the first agitator and the rotation center of the second agitator in the direction of gravity. The developing device according to claim 1. 3. The developing device according to claim 2, wherein the wiping direction of said wiping means is the same as the rotation direction of said first agitator. 4. In a developing device in which the rotation center of the first agitator is located above the rotation center of the second agitator in the direction of gravity, the developing is performed forward in a direction opposite to the developer replenishment timing detecting means of the wiping means. 4. The developing device according to claim 2, further comprising means for preventing a drop in the liquid level of the developer. 5. The developing device according to claim 4, wherein said developer water level lowering prevention means and said wiping means have substantially the same width. 6. A developer conveying means provided on both sides of a portion of the second agitator corresponding to the developer water level lowering preventing means. Developing device.