JPH11160990A - Developing device and electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an erroneous detecting action from being executed, to optimize the quantity of toner in a developing container and to make an image excellent by providing a device with an electrical conductive member with which a toner scraping member is brought into contact before it is passed through the surface of a sensor detecting the residual quantity of the toner. SOLUTION: The end part 124a of a stirring spring 124 is brought into contact with the surface of a sensor oscillator 123 and the end surface of a ground bar 126. The spring 124 is arranged on this side of the oscillator 123 in the moving direction of the end part 124a of the spring 124 so that the end part 124a is brought into contact with the bar 126 and the oscillator 123 in this turn and electric charge is hardly generated again after it is brought into contact with the bar 126. Therefore, the spring 124 is brought into contact with a ground plate arranged so that the height thereof becomes almost identical to that of the oscillator 123 incorporated in the developing container 102 once before the spring 124 is passed through the oscillating surface of the toner residual quantity detection sensor 121. Thus, the erroneous detecting action is prevented from being executed because the electric charge by the developing bias of a developing sleeve or the electric charge by static electricity flows to the sensor 121.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an electrophotographic image forming apparatus such as a copying machine or a printer adopting an electrophotographic method, and an electrophotographic image forming apparatus having the developing device.

[0002]

2. Description of the Related Art Conventionally, a developing device for developing a latent image formed on a photosensitive drum using toner detects a developing sleeve and the remaining amount of toner in a developing container 102 as shown in FIG. And a member 106 for stirring the toner in the developing container.
And a toner replenishing means for replenishing the toner to the developing container by the input and output of. This toner remaining amount detection sensor 12
As one, there is one provided with a piezoelectric vibrator.

[0003] A stirring spring 124 is attached on the axis of the stirring means 106 to scrape off toner adhered to the surface of the vibrator 123 of the toner remaining amount detecting sensor 121.

Here, the stirring means 106 and the stirring spring 124 are generally made of metal such as stainless steel.

On the other hand, the developing sleeve is always applied with a developing bias, and the toner is
Because it is charged with stirring,
In order to prevent these charges from flowing to the toner remaining amount detection sensor 121 via the stirring means 106 and the stirring spring 124 and erroneously detecting them, the ground plate 125 and the stirring means 10 are used.
The ground is taken by the contact g of the end of the shaft 106a of No. 6.

[0006]

The present invention is a further development of the prior art.

A first object of the present invention is to provide a developing apparatus and an electrophotographic image forming apparatus capable of always adjusting the amount of toner in a developing container and preventing image defects from occurring even when the developing container is durably used. To provide.

A second object of the present invention is to provide a developing apparatus and an electrophotographic image forming apparatus which can prevent the generation of radiation noise which adversely affects other electric appliances generated from the developing container even when the developing container is used for a long time. To provide.

[0009]

Means for Solving the Problems The main aspects of the present invention are shown below with the same reference numerals as those in the claims.

According to a first aspect of the present invention, there is provided a developing device for developing a latent image formed on an electrophotographic photosensitive drum using toner, wherein a developing sleeve and a remaining amount of toner in a developing container are detected. Sensor for stirring the toner in the developing container, a member for scraping off the toner attached to the surface of the toner sensor in the developing container while rotating, and a toner container for input / output of the toner sensor. A toner supply means for supplying toner to the toner sensor in the developing container, and a conductive member for touching a member for scraping off toner attached to the surface of the toner sensor before passing through the surface of the toner sensor. It is.

According to a twelfth aspect of the present invention, there is provided an electrophotographic image forming apparatus having a developing device for developing a latent image formed on an electrophotographic photosensitive drum and forming an image on a recording medium. The apparatus includes a developing sleeve, a toner sensor for detecting a remaining amount of toner in the developing container, a member for stirring the toner in the developing container, and a toner attached to the surface of the toner sensor in the developing container while rotating. A member for scraping off toner, a toner replenishing means for replenishing toner to the developing container by input and output of the toner sensor, and a member for scraping off toner attached to the surface of the toner sensor in the developing container passes through the surface of the toner sensor. An electrophotographic image forming apparatus comprising: a conductive member to be touched before.

[0012]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an enlarged top view of the developing device according to the present invention, particularly the vicinity of the toner remaining amount detection sensor 121, FIG. 2 is a plan view showing a state in which a cover of the developing device is removed, and FIG.
3 is a plan view of a cover of the developing device, and FIG. 5 is a longitudinal sectional view of an electrophotographic copying machine provided with the developing device according to the present invention.

First, a schematic configuration of the electrophotographic copying machine will be described with reference to FIG.

A photosensitive drum 11 as an image carrier is rotatably housed in an apparatus body 10 of an electrophotographic copying machine. A primary charger 12 is provided around the photosensitive drum 11, and a developing device according to the present invention. 1, transfer charger 13, separation charger 1
4. Process equipment such as a cleaning device 15 is provided. A hopper 116 for replenishing toner as a developer is disposed above the developing device 1.

Further, on one side (right side in FIG. 5) of the apparatus main body 10, paper feed cassettes 17, 18, and 19 each of which accommodates a plurality of transfer papers P in a stacked state are provided in three upper and lower stages. Yes,
Above the paper feed cassette 17, a manual paper feed tray 20 is provided.
Is provided.

Thus, each of the sheet cassettes 17, 18, 19
Or the transfer paper P supplied from the manual paper feed tray 20
5 is conveyed from the right to the left in FIG. 5 in the apparatus main body 10, and a registration roller 21, a conveyance belt 22, a fixing device 23, a paper discharge roller 24, and the like are arranged on the conveyance path.

On the other hand, a lamp 25, reflection mirrors 26 to 29, an optical lens 30 and the like which constitute an optical system are arranged in the upper part of the apparatus main body 10.

An original (not shown) set on an original mounting table 31 provided on the upper surface of the apparatus main body 10 is read by an optical system, and an optical image corresponding to the original is rotated on the photosensitive drum 11. The photosensitive drum 11
An electrostatic latent image is formed thereon, and the electrostatic latent image is developed by the developing device 1 according to the present invention and is visualized as a toner image.

On the other hand, for example, transfer paper P is supplied from the paper feed cassette 17 and the transfer paper P is
The toner image formed on the photosensitive drum 11 is transferred by being transferred to the transfer unit between the photosensitive drum 11 and the transfer charger 13 at the same timing, and thereafter, the photosensitive drum is actuated by the operation of the separation charger 14. 11 is separated.

The transfer paper P separated from the photosensitive drum 11 is transported by the transport belt 22 to the fixing device 2.
After the toner image is fixed to the toner image by the fixing device 23, the toner image is discharged to the outside by the paper discharge roller 24.

Next, the developing device 1 according to the present invention will be described.

In the developing device 1 shown in FIG. 4, reference numeral 102 denotes a developing container for storing the toner t therein, and an upper portion of the developing container 102 is covered by a cover 103. At the opening of the developing container 102, a developing sleeve 104, which is a developer carrying member that is arranged to face the photosensitive drum 11 and is driven to rotate in the direction of the arrow shown in the figure, is provided. A developing blade 108 is fixed to the developing container 102, and the developing blade 108 is
4 to regulate the layer thickness of the toner layer and apply a triboelectric load to the toner.

A first stirring chamber S1 and a second stirring chamber S2 are formed in the developing container 102.
In the stirring chamber S1 and the second stirring chamber S2, a first stirring unit 105 and a second stirring unit 106, which are driven to rotate in the directions of arrows in FIG. 4, are provided, respectively. Further, at an end of the developing container 102 opposite to the side on which the developing sleeve 104 is disposed, a conveying screw 107 as conveying means is disposed in parallel with the developing sleeve 104 (see FIG. 2). The transport screw 107 is provided at a position higher than the developing sleeve 104 and the first and second stirring units 105 and 106.

On the other hand, a developing blade 108 for regulating the layer thickness of the toner t carried on the developing sleeve 104 is attached to the back surface of the cover 103, and one end in the width direction of the cover 103 (that is, one end in the width direction of the cover 103). As shown in FIG. 3, a rectangular toner supply port 103a is opened above the shaft end of the transport screw 107, and a toner supply port 116a of the hopper 116 is opened above the toner supply port 103a. (See FIG. 4).

In the developing device 1, when the toner t in the developing container 102 is consumed and its remaining amount is reduced, the remaining toner detecting sensor 121 provided on the longitudinal end wall of the developing container 102 is activated. Detecting that the amount of the toner t is low, the signal is sent to a control device (not shown) and displayed on a display (not shown) of the image forming apparatus main body 10. Thus, the user supplies toner to the toner hopper 116.

The developing container 102 is replenished from a hopper 116 through a toner replenishing port 103a. Then, the toner t replenished from the toner replenishing port 103a is conveyed by the conveying screw 107 in the developing container 102 in the longitudinal direction of the developing sleeve 104 (the direction perpendicular to the plane of FIG. 4 and the arrow C in FIG. 2).
(Hereinafter, simply referred to as a longitudinal direction), and in the middle of the first stirring chamber S1 from the screw wall 109.
To fall. Then, the toner t dropped into the first stirring chamber S1 is stirred by the first stirring means 105 which is driven to rotate in the direction of the arrow in FIG. The toner is agitated by the second agitating means 106 rotated and driven in the direction of arrow 4 and supplied to the developing sleeve 104 to be used for developing the electrostatic latent image formed on the photosensitive drum 11.

As shown in FIG. 1, the surface of the sensor vibrator 123 and the end surface of the earth rod 126 slightly protrude from the inner side surface 102a of the longitudinal end wall of the developing container 102. The end 124 a of the agitating spring 124 comes into contact with the surface of the sensor vibrator 123 and the end of the earth rod 126. This contact is made in the order of the ground rod 126 and the sensor vibrator 123 in the order of the end 124 of the stirring spring 124.
The end portion 124a is provided in front of the sensor oscillator 123 with respect to the moving direction of the end portion 124a so that the contact portion a is in contact with the ground bar 126 so that electric charge is not generated again after the contact.

According to the present embodiment, as shown in FIG. 1, the stirring spring 124 is connected to the toner remaining amount detecting sensor 1.
Before passing through the vibrating surface 21, the contact with the ground plate 126, which is built in the developing container 102 so as to be substantially at the same height as the sensor vibrator 123, is contacted by the developing bias of the developing sleeve 104. Or toner t
This prevents the charge such as static electricity due to the agitation by the first and second agitating means 15 and 16 from flowing to the toner remaining amount detection sensor 121 via the second agitating means 16 and the agitating spring 124, thereby preventing erroneous detection. For the development container 10
2, the amount of toner t can be made appropriate to prevent image defects.

Further, it is possible to prevent the generation of radiated noise from the developing container 102, which adversely affects other electric appliances.

(Embodiment 2) Further, as shown in FIG. 7, a contact portion of an agitating spring 124 of an earth plate 126 is provided in an arc shape surrounding a sensor vibrator 123, and a sensor vibration built in the developing container 102 is provided. By changing the shape and position of the ground plate 126 disposed so as to be substantially the same height as the child 123, it is possible to further enhance the effect,
The accompanying positions and shapes are naturally included in the present invention.

In the embodiment, the case where the sensor vibrator 123 is disposed in the second stirring chamber S2 has been described.
Is similarly effective when the sensor vibrator 123 is disposed

[0033]

As described above, according to the present invention, the conductive member to be touched is provided before the member for scraping off the toner passes through the surface of the sensor for detecting the remaining amount of toner. Charges due to the developing bias of the sleeve or charges such as static electricity due to the toner being stirred by the stirring means flow to the sensor for detecting the remaining amount of toner via the stirring means and the member which scrapes off the toner, thereby causing erroneous detection. Therefore, even if the developing device is used in a durable manner, the amount of toner in the developing container can always be set to an appropriate value, and the image can be kept good.

Further, even when the developing device is used for a long time, it is possible to prevent the generation of radiation noise which adversely affects other electric appliances generated from the developing device.

[Brief description of the drawings]

FIG. 1 is an enlarged top view of a portion B of the developing device of FIG.

FIG. 2 is a plan view showing a state where a cover of the developing device is removed.

FIG. 3 is a plan view of a cover of the developing device.

FIG. 4 is a sectional view of the developing device, taken along line AA of FIG. 2;

FIG. 5 is a longitudinal sectional view of an electrophotographic copying machine provided with a developing device according to the present invention.

FIG. 6 is a cross-sectional view taken along line AA of FIG. 2, showing a state where toner is not inserted in FIG. 4;

FIG. 7 is a cross-sectional view taken along the line AA of FIG. 2, showing a state where toner is not inserted in FIG. 4;

FIG. 8 is a plan view of a conventional example.

[Explanation of symbols]

 P: transfer paper S1: first stirring chamber S2: second stirring chamber t: toner 1: developing device 10: apparatus body 11: photosensitive drum 12: primary charger 13: transfer charger 14: separation charger 15: cleaning device DESCRIPTION OF SYMBOLS 17 ... Paper cassette 18 ... Paper cassette 19 ... Paper cassette 20 ... Paper tray 21 ... Register roller 22 ... Conveyer belt 23 ... Fixing device 24 ... Discharge roller 25 ... Lamp 26 ... Reflective mirror 27 ... Reflective mirror 28 ... Reflecting mirror 29 Reflecting mirror 30 Optical lens 31 Document mounting table 102 Developing container 102a Inner surface 103 Cover 103a Toner supply port 104 Developing sleeve 105 First stirring means 106 Second stirring means 107 Transport Screw 108: developing blade 116: hopper 116a: toner supply port 121: toner remaining amount detection sensorー 123 ・ ・ ・ Sensor vibrator 124 ・ ・ ・ Stirring spring 124a ・ ・ ・ End 125 ・ ・ ・ Earth plate 126 ・ ・ ・ Earth rod

Claims (12)

[Claims] 1. A developing device for developing a latent image formed on an electrophotographic photosensitive drum using toner, comprising: a developing sleeve; a toner sensor for detecting a remaining amount of toner in a developing container; A member for agitating the toner in the developing container, a member for scraping off the toner attached to the surface of the toner sensor in the developing container while rotating, a toner replenishing unit for replenishing the toner to the developing container by input and output of the toner sensor A conductive member that contacts a member that scrapes off toner adhered to the surface of the toner sensor in the developing container before passing through the surface of the toner sensor. 2. The time from when the member for scraping off the toner attached to the surface of the toner sensor in the developing container to the surface of the toner sensor after contacting and passing through the conductive member is longer than the surface of the toner sensor. 2. The developing device according to claim 1, wherein the developing device is arranged at a position shorter than a time required for passing through the conductive member and passing through the conductive member. 3. 3. The developing device according to claim 1, wherein the conductive member is connected to an electrical ground of the image forming apparatus main body. 4. A member for stirring the toner in the developing container, and a member for scraping off the toner attached to the surface of the toner sensor in the developing container while synchronizing and rotating with the operation of the stirring member. A developing device, wherein both are metal members. 5. The developing device according to claim 1, wherein the member that scrapes off the toner attached to the surface of the toner sensor rotates in synchronization with a member that stirs the toner. 6. The developing device according to claim 5, wherein the member for scraping off the toner attached to the toner sensor surface is attached to the toner stirring member. 7. The developing device according to claim 6, wherein the member for stirring the toner has a crank shape, and the member for scraping off the toner attached to the surface of the toner sensor is mounted on a journal of the member for stirring the toner. 8. A member for scraping off toner attached to the surface of the toner sensor is a torsion coil spring, one end of which is locked by a member for stirring toner, and the other end of which is connected to the conductive member and the toner sensor. The developing device according to claim 7, wherein the developing device is capable of contacting the surface. 9. The developing device according to claim 1, wherein the conductive member is provided apart from the toner sensor. 10. The developing device according to claim 1, wherein the conductive member surrounds a toner sensor. 11. A member for stirring the first toner for stirring the toner received from the toner replenishing means, and a second member for stirring the toner sent from the member for stirring the first toner and supplying the toner to the developing sleeve. A member for stirring the toner,
The developing device according to any one of claims 1 to 10, further comprising: a toner sensor and a conductive member arranged in a state where the toner sensor and the first toner are stirred. 12. An electrophotographic image forming apparatus having a developing device for developing a latent image formed on an electrophotographic photosensitive drum and forming an image on a recording medium, wherein the developing device comprises: a developing sleeve; A toner sensor for detecting the remaining amount of toner in the developing container; a member for stirring the toner in the developing container; a member for rotating and scraping off the toner attached to the surface of the toner sensor in the developing container; A toner replenishing unit that replenishes toner to the developing container by input and output of a sensor, a conductive member that contacts a member that scrapes off toner attached to the toner sensor surface in the developing container before passing through the surface of the toner sensor, An electrophotographic image forming apparatus comprising: