JPH1020640A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device where the deterioration of image quality such as the fogging of developer and the unstableness of density is not caused. SOLUTION: A toner hopper 43 is provided on the upside of a developing chamber 44 equipped with a developing roller 40, a doctor blade 41, a toner replenishing roller 39 and a toner residual amount detecting means. A discharge port 50 is provided at the lower part of the toner hopper 43, and a toner supply member 48 for supplying toner is turnably arranged at the upper part of the port 50. A light emitting element 45B and a light receiving element 45C for detecting the residual amount of the toner are provided on the upside in the chamber 44. In the case the residual amount of the toner becomes the fixed one, the member 48 is turned to supply the fixed amount of the toner to the chamber 44 from the port 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color electrophotographic recording apparatus such as an electronic copying machine, a laser beam printer, and a facsimile.

[0002]

2. Description of the Related Art In recent years, a color electrophotographic apparatus sequentially develops a plurality of developing devices of different colors on a belt-shaped photosensitive member, synthesizes a toner image on the photosensitive member with an intermediate transfer member, and collectively transfers the intermediate image onto paper. Such a configuration has been adopted. Conventionally, this type of color electrophotographic apparatus has a configuration in which one side of a photoreceptor belt is provided vertically, and a developing device is abutted against a vertical surface of the photoreceptor belt from a horizontal direction to perform development, or one side of a photoreceptor belt is provided horizontally, In general, a configuration is used in which a developing device is brought into contact with a horizontal surface of a photoreceptor belt from a vertical direction to perform development. However, recently, as described in, for example, Japanese Patent Application Laid-Open No. 4-318875, the latter configuration, which is advantageous in shortening the paper transport path, is becoming mainstream.

The process of visualizing an electrostatic latent image formed on a photoreceptor with toner is broadly divided into dry development and liquid development, and dry development is generally employed. . In dry development, there are a two-component development method using a toner containing a carrier (magnetic powder such as iron powder and ferrite) and a one-component development method using a toner not containing a carrier. The one-component developing method is becoming mainstream mainly in small copying machines. The one-component developing type developing device may have a relatively simple configuration as compared with the two-component developing type, and does not require a toner density control device, which is very advantageous for cost reduction and size reduction.

A developing device using the one-component developing method generally has a developing chamber for frictionally charging a one-component toner (hereinafter, simply referred to as toner) to make a thin layer on a developing roller, and a toner hopper for storing the toner. Although there is no particular member for blocking the two, there is a configuration in which the toner in the toner hopper is agitated by the toner conveying member and is sequentially conveyed to the developing chamber side.

Hereinafter, a conventional electrophotographic apparatus and a one-component developing apparatus used therein will be described with reference to the drawings.

FIG. 9 is a sectional view of a conventional electrophotographic apparatus, and FIG.
0 is a cross-sectional view of a conventional one-component developing device, and FIG. 11 is an enlarged view of a thin toner layer portion of the conventional one-component developing device.

In FIG. 9, a photosensitive belt 1 is formed by applying a photosensitive receiving layer such as an organic photoconductor (OPC) in a thin film shape. The photoreceptor belt 1 is tuned and supported by three photoreceptor belt support / conveyance rollers 2, 3, 4 so as to form a horizontal plane, and is driven by a drive motor (not shown). Along the circumference in the direction of arrow A. A one-component developing device (hereinafter simply referred to as a developing device) that stores toner of each color of black (B), yellow (Y), magenta (M), and cyan (C) along the outer peripheral surface of the photosensitive belt 1 7B, 7Y, 7
M, 7C are provided. A photoreceptor cleaning device 9, a static eliminator 10, and a charger 5 are provided below the photoreceptor belt 1, and a laser beam generator 6 is provided thereunder.

The charger 5 includes a charging wire 11 made of a tungsten wire or the like, a shield plate 12 made of a metal plate, and a grid plate 13. When a high voltage is applied to the charging line 11, the charging line 11 causes a corona discharge to uniformly charge the photosensitive belt 1 via the grid plate 13. A laser beam 14 is emitted from the laser beam generator 6 to the photoreceptor belt 1, and the laser beam 14 indicates image data. In the example of the laser printer, the laser beam 14 is controlled by a signal from a host computer (not shown), and a plurality of static colors corresponding to specific components among a plurality of predetermined color components are formed on the photoreceptor belt 1. An electrostatic latent image is formed.

The developing devices 7B, 7Y, 7M, and 7C of the respective colors are removably arranged in a horizontal direction at equal intervals in a predetermined storage portion provided in the main body of the apparatus, and are detachably arranged in a horizontal line. Are configured similarly. The contact cams 15B, 15Y, 15M, and 15C are used for developing the electrostatic latent images of a predetermined color, respectively.
The separation springs 16B, 16Y, 16M, and 16C are provided for bringing the developing devices 7B, 7Y, 7M, and 7C away from the standby position. . The contact cams 15B, 15
Y, 15M, and 15C are provided on the developing device attaching / detaching cover 17 on the upper surface of the apparatus main body. The developing device attaching / detaching cover 17 is supported by a fixed developing device attaching / detaching cover shaft 18 so as to be freely opened and closed.

The intermediate transfer body unit 8 includes a belt-shaped intermediate transfer body belt 19 made of a conductive resin or the like, and three intermediate transfer body belt supporting / conveying rollers 20 for adjusting and supporting the intermediate transfer body belt 19. 21 and 22. Here, the surface circumference of the intermediate transfer belt 19 is set to be equal to the surface circumference of the photosensitive belt 1. An intermediate transfer roller 23 is disposed opposite to the photosensitive belt 1 with the intermediate transfer belt 19 interposed therebetween. This intermediate transfer roller 2
Reference numeral 3 is provided for transferring the toner image on the photosensitive belt 1 onto the intermediate transfer belt 19. An intermediate transfer member belt cleaning device 24 is provided at a position facing the intermediate transfer member belt supporting and conveying roller. The intermediate transfer member belt cleaning device 24 is a device that scrapes residual toner on the intermediate transfer member belt 19, and
While the composite image is being formed thereon, it is separated from the intermediate transfer belt 19 and is in contact only when it is used for cleaning.

Paper cassette 25 containing paper 26
Is provided directly below the laser beam generator 6. The paper 26 is sent out one by one from a paper cassette 25 to a paper transport path 28 by a paper feed roller 27. Paper transport path 2
8 is provided with a registration roller 29. The registration roller 29 is provided for temporarily stopping the sheet 26 in order to match the position of the sheet 26 with the position of the composite image formed on the intermediate transfer belt 19, and is in pressure contact with the driven roller 30. ing. Further, a sheet transfer roller 31 is disposed at a position facing the intermediate transfer belt support roller 22. The paper transfer roller 31 transfers the composite image formed on the intermediate transfer belt 19 to the paper 26, and rotates in contact with the intermediate transfer belt 19 only when the composite image is transferred to the paper 26. A fixing device 32 is disposed downstream of the paper transfer roller 31. The fixing device 32 includes a heat roller 33 having a heat source therein and a pressure roller 34, and transfers the composite image transferred to the paper 26 to the heat roller 3.
With the nipping and rotation of the pressure roller 3 and the pressure roller 34, the toner image is fixed on the sheet 26 by pressure and heat to form a color image. Further, a pair of paper discharge rollers 35, 3
6 are arranged. Further, a discharge tray 37 for storing the sheets 26 is formed on the exit side of the discharge rollers 35 and 36.

The operation of the conventional electrophotographic apparatus configured as described above will be described below.

In FIG. 9, first, a high voltage is applied to a charging line 11 in a charger 5 connected to a high-voltage power supply to cause corona discharge, and the surface of the photoreceptor belt 1 is uniformly charged to -500 V to -500 V.
It is charged to about 650v. Next, the photoreceptor belt 1 is rotated in the direction of arrow A by a driving device (not shown), and a predetermined color of a plurality of color components, for example, black ( When the laser beam 14 corresponding to the image B) is irradiated, the irradiated portion on the photoreceptor belt 1 loses its charge and an electrostatic latent image is formed. On the other hand, in the developing device 7B in which the black toner contributing to the development is stored, the contact cam 15B makes a half rotation by the color selection signal from the host computer (not shown), and thereby comes into contact with the photosensitive belt 1. In the developing device 7B in which the development is completed, the contact cam 15B is further rotated by a half turn, and the separation spring 1B is rotated.
By the spring force of 6B, the photosensitive drum 1 moves from the contact position to the photosensitive belt 1 to the standby position. While the developing device 7B is developing, the other developing devices 7Y, 7M, and 7C are separated from the photosensitive belt 1. Next, for example, when the color of cyan (C) is selected, the developing device 7C is brought into contact with the photoreceptor belt 1 and starts developing cyan.

In the case of a copying machine or a printer using four colors, the developing operation is sequentially repeated four times, and the toner images of four colors B, C, M and Y are superimposed on the intermediate transfer belt 19 to form a composite image. Form. The composite image formed in this way is applied to a paper transfer roller 31 at a high voltage having a polarity opposite to that of the toner, and is collectively transferred to the paper 26 sent from the paper cassette 25 along the paper transport path 28 by the pressure.
Subsequently, it is sent to the fixing device 32, where the heat and the heat roller 3
3 is fixed by the holding force of the pressing roller 34 and a color image is formed. The paper 26 that has passed through the fixing device 32 passes through a pair of paper discharge rollers and is discharged to a paper discharge tray 37.

Referring now to the drawings, the developing device (7B)
Will be described in detail. Inside the developing device (7B)
A plurality of agitators 38 are formed to be bent in a rectangular shape by a wire, a resin, or the like, and both ends thereof are rotatably supported. The agitator 38 draws a trajectory of a circle indicated by a dashed line in conjunction with the rotation of the toner supply roller 39, agitates the toner supplied into the developing device 7 </ b> B to prevent coagulation, and agitates the toner. Transport to Both ends of the toner replenishing roller 39 are rotatably supported by a toner hopper, and replenish the toner agitated and transported by the agitator 38 to the surface of the developing roller 40.

The toner replenishing roller 39 is made of a metal such as stainless steel as a base material, and a conductive layer made of an elastic material such as urethane or silicon is formed in a layer on the outer peripheral surface thereof. It is rotatably supported and rotates counterclockwise. The toner supply roller 39 has a predetermined bite amount with the developing roller 40 to stabilize the charge amount due to friction with the toner.

The developing roller 40 is made of a metal such as stainless steel as a base material, and a conductive elastic body such as urethane or silicon is formed in a layer on the outer peripheral surface thereof. Further, the developing roller 40 is rotatably supported at both ends of the developing device 7B. It is driven to rotate counterclockwise. The doctor blade 41 is formed of a conductive member such as silicon or urethane formed at the same time as a stainless steel leaf spring, and frictionally charges the toner supplied by the toner supply roller 39 to form an outer peripheral surface of the developing roller 40. To form a thin layer state. A developing roller 4 is provided below a contact portion between the developing roller 40 and the toner supply roller 39.
A recovery sheet 42 that comes into contact with zero is attached. The recovery sheet 42 is made of urethane, PET (polyethylene terephthalate), or the like, and prevents toner leakage due to toner backflow from the developing chamber.

The operation of the conventional developing device constructed as described above will be described below. First, the toner in the toner hopper 43 is transported onto the toner supply roller 39 by the agitator 38. The toner conveyed onto the toner supply roller 39 is supplied to the toner supply roller 39 and the developing roller 40.
And is attached to the surface of the developing roller 40 by electrostatic force. The attached toner layer is conveyed to the pressure contact portion with the doctor blade 41 while being carried on the surface of the developing roller 40 by the rotation of the developing roller 40.
The transported toner is subjected to a frictional action between the developing roller 40 and the doctor blade 41, further increasing the amount of triboelectric charge and regulating the toner layer thickness to form a uniform thin layer state.

The toner that has passed through the doctor blade 41 is transported in a thin layer while maintaining the above-mentioned amount of triboelectric charge to a contact position (developing area) with the photoreceptor belt 1. When a potential difference is applied between the developing roller 40 and the photoreceptor belt 1 while the toner layer is in contact with the photoreceptor belt 1 at this contact position, the toner is transferred and adheres to the electrostatic latent image portion formed on the photoreceptor belt 1 Then, a visible image is formed and development is completed. Further, the toner not transferred and attached to the photoreceptor belt 1 is
The recovery sheet 42 and the developing roller 40 remain thin.
, Is scraped off by the toner supply roller 39, and is returned to the developing chamber 7B again.

[0020]

However, in the above-described conventional developing device configuration, the flow of the toner stagnates or blocks in the portion B in FIG. There is a problem that a proper charge amount cannot be given, and the image quality is greatly deteriorated.

In general, as shown in FIG. 11, the one-component toner is rotated by the rotation of the developing roller 40 made of a material having a high friction coefficient such as urethane or silicon, and similarly from the material having a high friction coefficient such as urethane or silicon. When the doctor blade 41 is pressed, the individual toners are frictionally rolled to obtain electric charges. If the load C (pressing force) against which the doctor blade 41 presses the developing roller 40 is insufficient, the amount of toner passing therethrough increases, and the toner in the upper layer (the layer farther from the surface of the developing roller) increases. The rotation of the developing roller 40 is less likely to be affected, and the charge amount is reduced.

As a result, toner scattering occurs, the transfer process is not performed properly, fog (toner adhesion to non-image portions) increases, image density becomes unstable, and high image quality and high resolution Will be difficult. in this case,
Although the toner in the toner hopper 43 is stirred by the rotation of the agitator 38, the toner is accumulated in the portion B and condensed over time due to the influence of gravity. Accordingly, the pressing force C of the doctor blade 41 decreases, and the charge amount of the toner decreases.

Therefore, the pressing force C of the doctor blade 41 is
There is also a means to increase the toner force condensed in the portion B, but since an elastic material is used for the material of the developing roller 40, creep occurs on the roller surface and abrasion becomes severe, and further This results in image quality degradation.

FIG. 12 is a sectional view of a conventional one-component developing apparatus according to another example. As shown in FIG. 12, there is a means for disposing the toner hopper 43 obliquely upward from the developing chamber 44 so that the toner does not accumulate freely around the doctor blade 41. However, since the width D of the developing device 7B is increased, The circumference of the belt 1 becomes longer, and the apparatus body becomes larger. Another problem is that if the capacity of the toner hopper 43 is reduced, the developing device must be frequently replaced.

An object of the present invention is to provide a developing apparatus which does not cause deterioration in image quality such as fogging of a developer and unstable density.

[0026]

A developing device according to the present invention includes a developing roller for supplying a developer held on a surface to a developing object, a developer supply roller for supplying a developer to the surface of the developing roller, A developing chamber in which a layer thickness adjusting means for adjusting the developer on the surface of the developing roller to a predetermined thickness is disposed; and a developer storage section disposed above the developing chamber and storing the developer therein. The developing device includes a detecting unit that detects a remaining amount of the developer in the developing chamber, and a fixed amount of developer supplying unit that supplies a fixed amount of the developer from the developing chamber storage unit to the developing chamber according to a detection output of the detecting unit. It is a thing.

In the developing device according to the present invention, the detecting means monitors the remaining amount of the developer in the developing chamber. And
When the remaining amount of the developer in the developing chamber reaches a predetermined amount, the developer constant supply means supplies the developer from the developer storage unit into the developing chamber. For this reason, the amount of the developer in the developing chamber is always kept within a certain range, so that the thickness of the developer on the developing roller surface by the layer thickness adjusting means can be kept at a predetermined amount. As a result, deterioration in image quality such as fogging of the developer and unstable image density can be prevented, and a highly reliable developing device can be obtained.

[0028]

According to a first aspect of the present invention, there is provided a developing device for supplying a developer held on a surface to a developing object, a developer supply roller for supplying a developer to the surface of the developing roller, and A developing chamber in which a layer thickness adjusting means for adjusting the developer on the surface of the developing roller to a predetermined thickness is disposed, and a developer storage section disposed above the developing chamber and storing the developer therein. In the developing device, detecting means for detecting the remaining amount of the developer in the developing chamber, and developer constant supply means for supplying a fixed amount of developer from the developer storage to the developing chamber in accordance with the detection output of the detecting means. It is provided.

Thus, by keeping the amount of the developer in the developing chamber within a certain range, it is possible to suppress the deterioration of the image quality such as the fog and the unstable density of the developer.

According to a second aspect of the present invention, in the developing device according to the first aspect of the present invention, the developer constant supply means is provided between the developing chamber and the developer storing section, and Provided with an outlet for discharging the developer from the developer storage to the developing chamber, and a supply member for supplying the developer through the outlet.

As a result, since the developer is supplied to the developing chamber through the discharge port at a constant rate, deterioration of the image quality due to stagnation and condensation of the developer can be prevented.

According to a third aspect of the present invention, in the developing device according to the first aspect of the present invention, the developer storage section has a vertically stacked opening at the bottom for discharging the developer. It has a plurality of storage containers, and the developer fixed amount supply means includes an opening / closing member for opening and closing an opening of the storage container.

Thus, a fixed amount of the developer stored in each of the plurality of storage containers can be supplied into the developing chamber according to the opening / closing operation of the opening / closing member, thereby preventing the deterioration of the image quality.

According to a fourth aspect of the present invention, in the developing device according to the third aspect of the present invention, the opening and closing member is
It comprises a lid member that opens and closes the opening by rotating about an axis arranged around the opening of the storage container.

Accordingly, when the lid member is opened, a fixed amount of the developer is sequentially supplied downward through the opening at the bottom of the storage container. By such an operation, the amount of the developer in the developing chamber is kept within a certain range, and deterioration of the image quality is prevented.

According to a fifth aspect of the present invention, in the developing device according to the third aspect of the present invention, the opening and closing member comprises:
It comprises a plate-like lid member extending in opposite directions about the rotation axis and rotating around the rotation axis.

Thus, when the lid member rotates, the opening at the bottom of the storage container is opened, and a certain amount of the developer is sequentially supplied downward. As a result, the amount of the developer in the developing chamber can be kept within a certain range, and the deterioration of the image quality can be prevented.

According to a sixth aspect of the present invention, in the developing device according to the fourth or fifth aspect of the present invention, the plurality of lid members are sequentially opened from the lower side in accordance with the detection output of the detecting means. The amount of the developer stored in the storage container is supplied to the developing chamber.

Thus, the developer stored in each of the plurality of stacked storage containers is sequentially supplied into the developing chamber, so that the amount of the developer in the developing chamber can be kept within a predetermined range. Image quality can be prevented from deteriorating.

According to a seventh aspect of the present invention, in the configuration of the developing device of the first to sixth aspects of the present invention, the detecting means is provided at a predetermined position above the developer supply roller in the developing chamber. And light receiving means for receiving light from the light emitting means.

Thus, the remaining amount of the developer in the developing chamber can be easily detected, and the amount of the developer in the developing chamber can be kept within a predetermined range.

Hereinafter, an electrophotographic apparatus and a developing apparatus according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an electrophotographic apparatus according to the first embodiment of the present invention, and FIG. 2 is a sectional view of a developing device (one component) according to the first embodiment of the present invention. Here, since the configuration and operation of the conventional electrophotographic apparatus other than the developing device are the same, the detailed description will not be repeated.

In FIG. 2, a developing roller 44, a toner supply roller 39, a doctor blade 41,
A toner remaining amount detecting member 45, a first agitator 46, and a recovery sheet 42 are provided. The developing roller 40 is formed by winding and bonding a silicone rubber having a rubber hardness of 60 ° (Asker C) and a rubber thickness of 1 mm in a roll shape to a stainless steel core material, an outer diameter of φ22 mm, and a surface roughness of 1 ≦ Rz μm.
Polished to ≦ 3. The toner supply roller 39 was formed by winding and bonding a urethane foam sponge to a stainless steel core material in a roll shape, and polishing the outer diameter to 22 mm. Developing roller 40
Both ends of the toner supply roller 39 and the toner supply roller 39 are rotatably supported by the developing chamber 44, and the surface of the roller portion is in contact with a bite of 0.5 mm.

The toner supply roller 39 is a developing roller.
It is rotated at a ratio of 0.9 to a peripheral speed of 40. Doc
Tar blade 41 is a stainless steel plate having a thickness of 0.15 mm.
Urethane with rubber hardness 70 ° (Asker C) at the tip of the spring
Rubber is integrally molded, and a sheet metal 47 having a thickness of 2 mm is supported.
Is fixed to the developing chamber 44. To the developing roller 40
The pressing force P of the doctor blade 41 becomes 120 gf / cm
The developing roller 40 after setting and passing the doctor blade 41
0.6 mg / cm of toner layer thickness ^Two, Electrification
The amount was defined between -13 and -15 [mu] C / g.

The first agitator 46 is formed of a polystyrene resin, and rotates in a clockwise direction along the trajectory of a circle indicated by a dashed line in conjunction with the rotation of the toner supply roller 39.
This prevents the toner in the developing chamber 44 from condensing. Reference numeral 45A denotes a window for detecting the remaining amount of toner, which is made of polymethyl methacrylate and has excellent transparency, and is provided on both sides of the developing chamber 44.

FIG. 3 is a block diagram of the toner remaining amount detecting means. The toner remaining amount detecting means 45 detects the presence or absence of light transmission between the light emitting element 45B and the light receiving element 45C attached to the apparatus main body. The first agitator 46 includes a cleaning member 4.
5D is attached, and rotates with the first agitator 46 to periodically contact the surface of the toner remaining amount detection window 45A to wipe off the toner from the inner surface of the toner remaining amount detection window 45A to perform cleaning. The position of the toner remaining amount detection window 45A is set at a position where about 40 g of toner remains when the toner remaining amount detecting means 45 performs the detecting operation.

Next, as shown in FIG. 2, a toner hopper 43 for storing toner is disposed vertically above the developing chamber 44.
A toner supply member 48 and a second agitator 49 are provided inside the toner hopper 43. A toner outlet 50 is provided at the bottom of the toner hopper 43, and forms a toner supply path from the toner supply member 48. The toner supply member 48 was formed by winding and bonding a urethane foam sponge to a stainless steel core material in a roll shape, and polished to an outer diameter of 26 mm. At one end of the toner discharge port 50, a protruding portion 51 for scraping off the toner attached to the toner supply member 48 is provided, and the sponge portion of the toner supply member 48 is bitten by 1 mm. The toner supply member 48 is a motor (not shown) on the main body side.
The rotation speed was set to 20 rpm, and the amount of toner supplied to the developing chamber 44 was set to about 40 g / min.

A second agitator 49 made of a polystyrene resin member is provided diagonally above the toner supply member 48 to agitate the toner accumulated in the toner hopper 43 downward and accumulate the toner on the toner supply member 48. It is composed.

The operation of the developing device configured as described above will be described. First, the toner in the developing chamber 44 is agitated by the first agitator 46 and is conveyed in the upper direction of the toner supply roller 38. The toner conveyed onto the toner supply roller 38 is frictionally charged by the contact between the toner supply roller 38 and the developing roller 40 and adheres to the surface of the developing roller 40 by electrostatic force. The attached toner layer is the developing roller 4
With the rotation of 0, the toner is conveyed to the pressure contact portion with the doctor blade 41 while being carried on the surface of the developing roller 40. The transferred toner is a developing roller 40 and a doctor blade 41.
, The frictional charge is further increased, and the thickness of the toner layer is regulated to form a uniform thin layer state.

As described above, the toner has a thin layer with a toner layer thickness of 0.6 mg / cm ² and a charge amount of -13 to -15 μC / g. The toner that has passed through the doctor blade 41 is transported to a contact position (developing area) with the photosensitive belt 1. At this contact position, the toner layer is
When a potential difference is applied between the developing roller 40 and the photoreceptor belt 1 while making contact with the toner, the toner is transferred and adheres to the electrostatic latent image portion formed on the photoreceptor belt 1 to form a visible image and development is performed. finish. Further, the toner that has not been transferred and adhered on the photoreceptor belt 1 passes between the recovery sheet 42 and the developing roller 40 in a thin layer state, and is supplied to the toner replenishing roller 38.
And is returned into the developing chamber 44 again.

Here, while the developing roller 40 is rotating, the light emitting element 45B for detecting the remaining amount of toner sends a signal (ultraviolet light) to the light receiving element 45C at a rate of 10 times / sec.
When C is received six times or more, that is, when the remaining amount of toner in the developing chamber 44 reaches about 40 g, it is determined that the remaining amount of toner is insufficient, and this is a mark for supplying toner from the toner hopper 43. The amount supplied in response to one detection is 40 g, and is not supplied until the remaining amount of toner becomes insufficient again. in this case,
The maximum amount of toner existing in the developing chamber 44 is about 80 g. With this toner amount, the strictest white paper printing is continuously performed as a condition, and the result of the toner charge amount for each number of printed sheets at that time is shown in FIG.

Conventionally, fogging occurred around 3,000 sheets, but after printing 12,000 sheets, the toner charge amount was stable, and there was no fog or density fluctuation. This means that the maximum amount of toner in the developing chamber 44 is
This indicates that the amount is not an amount that affects the pressing of No. 1 but an appropriate amount. As a result, the regular toner layer thickness,
A stable charge amount was secured, and high reliability and high image quality were realized.

Next, a developing device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a sectional view of a developing device (one component) according to a second embodiment of the present invention, and FIG. 6 is a perspective view of a divided toner hopper according to the second embodiment of the present invention. Here, since the electrophotographic apparatus main body and the developing chamber of the developing apparatus have the same configuration and operation as those of the first embodiment of the present invention,
Detailed description is omitted.

As in the case of the developing device of the first embodiment, a plurality of toner hoppers 43 containing toner are arranged vertically above the developing chamber 44. In this case, it is divided into four layers, and each divided toner hopper 43A, 43
B, 43C, and 43D are provided with a toner supply opening 52 and a resin opening lid 53 that closes the toner supply opening 52 at the bottom, and have a capacity to accommodate 40 g of toner. A coil spring 54 is attached to each of the opening and closing pivots of the opening lid 53, and urges the opening lid 53 to open in the direction of arrow E.

A stopper 55 is provided at one end of the opening lid 53.
Are protruding and are engaged with the output shaft member 57 of the 回 転 rotation solenoid 56 attached to the main body side. The gear 58 of each solenoid 56 is connected to a main body motor (not shown), and the opening lid 53 is opened when the solenoid 56 is turned on.

The timing and the operation of supplying the toner are the same as those of the developing device of the first embodiment. After the detection of the remaining amount of toner in the developing chamber 44, the solenoid 56 attached to the lowermost divided toner hopper 43A is turned on. Then, the stopper 55 is released with the rotation of the output shaft member 57, and the toner is supplied to the developing chamber 44 collectively. Opening lid 53 after supply
Maintains the open state, the upper divided toner hopper 43B,
The toner from 43C and 43D is easily passed. Next, when the remaining amount of toner in the developing chamber 44 is detected,
The opening lid 53 of the divided toner hopper 43B, which is one layer above the previous divided toner hopper 43A, opens to supply the toner to the developing chamber 44. These operations are repeated to supply the toner to the uppermost divided toner hopper 43D. By supplying the toner collectively in a stepwise manner as described above, the pressure of the doctor blade 41 does not change with time as in the first embodiment, and the regular toner layer thickness and charge amount can be stably ensured, and high reliability is ensured. Quality and high image quality.

Further, a developing device according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a sectional view of a developing device (one component) according to a third embodiment of the present invention.
FIG. 9 is a perspective view of a toner hopper according to a third embodiment of the present invention. Here, the electrophotographic apparatus main body and the developing chamber of the developing apparatus have the same configuration and operation as those of the first embodiment of the present invention, and therefore detailed description is omitted.

As in the case of the developing device of the first embodiment, a toner hopper 43 containing toner is disposed vertically above the developing chamber 44. In this case, four toner supply regulating members 59 (59A, 59B,
59C, 59D) are rotatably supported at both ends, and two blades 60 are integrally formed of a resin member with a symmetrical rotation axis. Normally, the blade portion 60 holds the horizontal position and stores 40 g of toner above the blade portion 60.

The rotary shafts are engaged with solenoids 61 attached to the main body, respectively, and the solenoid gear 62 is connected to a main body motor (not shown). The configuration is such that the toner rotates and the toner falls to the lower layer. The timing and the operation of supplying the toner are the same as those of the developing device of the first embodiment. After detecting the remaining amount of the toner in the developing chamber 44, the solenoid 61 attached to the lowermost toner supply regulating member 59A is turned on. With the rotation of the shaft, the blade portion 60 moves in the direction of arrow F.
, And the toner is supplied collectively into the developing chamber 44.

After the supply, the blade portion 60 maintains a vertical state,
The toner from the upper layer is made to pass easily. Next, when the remaining amount of toner in the developing chamber 44 is detected, the toner supply regulating member 59 </ b> B on one of the previous toner supply regulating members 59 </ b> A rotates to supply toner to the developing chamber 44. By repeating these operations, the uppermost toner supply regulating member 5
The toner is supplied up to 9D. By supplying the toner collectively in a stepwise manner as described above, the pressure of the doctor blade 41 does not change with time as in the first embodiment, and the regular toner layer thickness and charge amount can be stably ensured, and high reliability is ensured. Quality and high image quality.

[0061]

As described above, according to the present invention, each time the remaining amount of the developer in the developing chamber reaches a certain amount, a fixed amount of the developer is supplied from the developer storing section into the developing chamber. By doing so, the amount of the developer in the developing chamber is maintained within a certain range, so that it is possible to suppress the toner layer thickness variation or the charge amount variation of the developing roller due to the quantitative variation of the developer, As a result, highly reliable and high-quality image reproduction without fogging or density fluctuation of the developer can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electrophotographic apparatus according to a first embodiment of the present invention.

FIG. 2 shows a developing device (one component) according to the first embodiment of the present invention.
Cross section of

FIG. 3 is a configuration diagram of a toner remaining amount detecting unit of the developing device according to the first embodiment of the present invention;

FIG. 4 is a correlation diagram showing the relationship between the toner charge amount and the number of printed sheets.

FIG. 5 shows a developing device (one component) according to a second embodiment of the present invention.
Cross section of

FIG. 6 is a perspective view of a divided toner hopper according to a second embodiment of the present invention.

FIG. 7 shows a developing device (one component) according to a third embodiment of the present invention.
Cross section of

FIG. 8 is a perspective view of a toner hopper according to a third embodiment of the present invention.

FIG. 9 is a sectional view of a conventional electrophotographic apparatus.

FIG. 10 is a sectional view of a conventional one-component developing device.

FIG. 11 is an enlarged view of a thin toner layer portion of a conventional one-component developing device.

FIG. 12 is a sectional view of a one-component developing device according to another example of the related art.

[Explanation of symbols]

 Reference Signs List 1 photoreceptor belt 6 laser beam generator 7B, 7Y, 7M, 7C developing device 8 intermediate transfer unit 39 toner replenishing roller 40 developing roller 41 doctor blade 43 toner hopper 44 developing chamber 45 remaining toner detecting means 48 toner supply member 50 discharging Outlet 51 Projection 52 Toner supply opening 53 Opening lid 59A, 59B, 59C, 59D Toner supply regulating member 60 Blade

Claims (7)

[Claims] A developing roller for supplying the developer held on the surface to the object to be developed, a developer supply roller for supplying the developer to the surface of the developing roller, and a developing roller for supplying the developer on the surface of the developing roller. A developing chamber in which a layer thickness adjusting means for adjusting to a predetermined thickness is disposed, and a developer storage unit disposed above the developing chamber and storing the developer therein; Detecting means for detecting the remaining amount of the developer in the developing chamber; and a fixed-quantity developer supplying means for supplying a fixed amount of the developer from the developer storage unit to the developing chamber in accordance with a detection output of the detecting means. A developing device comprising: 2. The developer metering means is provided between the developing chamber and the developer storage section, and has an outlet for discharging the developer from the developer storage section to the developing chamber. The developing device according to claim 1, further comprising: a partition wall configured to supply the developer through the discharge port. 3. The developer storage section has a plurality of storage containers stacked vertically and having an opening at the bottom for discharging the developer. The developing device according to claim 1, further comprising an opening / closing member that opens and closes the opening of the container. 4. The storage device according to claim 3, wherein the opening and closing member comprises a lid member that opens and closes the opening by rotating around an axis disposed around the opening of the storage container. The developing device as described in the above. 5. The developing device according to claim 3, wherein said opening / closing member comprises a plate-like lid member extending in opposite directions about a rotation axis and rotating around said rotation axis. 6. A method according to claim 6, wherein a plurality of said lid members are sequentially opened from a lower side in accordance with a detection output of said detection means to supply a fixed amount of said developer stored in said storage container to said developing chamber. The developing device according to claim 4. 7. A light emitting means for projecting light into the developing chamber at a predetermined position above the developer supply roller in the developing chamber, and a light receiving means for receiving light from the light emitting means. The developing device according to claim 1, further comprising: