JP2877014B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic recording apparatus such as an electrocopier, a laser beam printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus mainly uses a device using dry toner, and has been practically used as many copying machines, laser beam printers and the like, and has achieved remarkable development. This image forming apparatus is an apparatus to which an electrophotographic process technology is applied, and visualizes an electrostatic latent image formed on a photoconductor having a photosensitive layer with toner particles. A developing device of an image forming apparatus employing a one-component developing method using only a toner as a developer generally includes a toner thin layer portion that frictionally charges the toner and thins it on a developing roller, and a toner hopper that stores the toner. Have. The toner in the toner hopper is supplied to the toner replenishing roller by the toner transport member, and the supplied toner is transported to the developing roller by friction between the developing roller and the toner replenishing roller. The toner conveyed onto the developing roller is charged by frictional force between the developing roller and the doctor blade, and forms a thin layer on the developing roller. Part of the thin layer toner on the developing roller is used to visualize the electrostatic latent image formed on the photoconductor, while the remaining unused toner is a polyethylene terephthalate (PET) sheet and a developing roller. And is returned to the hopper again. The flow of toner can be roughly classified into toner circulating in the toner hopper to prevent blocking (solidification), toner for visualizing an electrostatic latent image, and visualization of an electrostatic latent image. It is divided into unused toner. Here, the amount of toner supplied from the inside of the toner hopper to the toner replenishing roller must be an amount of toner required to visualize the electrostatic latent image. This results in a multi-layer state, causing excessive development and toner leakage. On the other hand, when the value is lower than the required value, the necessary minimum amount of toner is not replenished onto the developing roller, resulting in insufficient development. In either case, the image is adversely affected. Therefore, various measures have been taken to regulate the amount of toner supplied from the inside of the toner hopper to the toner supply roller.

A developing device of a conventional image forming apparatus will be described below with reference to the drawings. FIG. 12 is a side view of an image forming apparatus provided with a conventional developing device, FIG. 13 is a side view of a developing device in the conventional image forming apparatus, and FIG. 14 is a perspective view of the developing device in the conventional image forming apparatus.

In FIG. 12, reference numeral 1 denotes a photosensitive member having a metal belt made of aluminum or the like as a base material, and a photosensitive receiving layer such as selenium (Se) or an organic photoconductor (OPC) applied on the outer peripheral surface thereof in a thin film form. Body. The photoreceptor 1 is tuned and supported by three photoreceptor belt supporting and conveying rollers 2, 3 and 4 so that a vertical plane is formed between the photoreceptor belt supporting and conveying rollers 2 and 3, and is driven by a drive motor (not shown). It rotates circumferentially in the direction of arrow A along the photoreceptor belt supporting and conveying rollers 2 and 3.

On the peripheral surface of the belt-shaped photoconductor 1, a charger 5, an exposure optical system 6, black (B), yellow (Y), magenta (M), and cyan ( Developing devices 7B, 7Y, 7 for storing the developers of each color of C)
M, 7C, an intermediate transfer body unit 8, a photoconductor cleaning device 9, and a static eliminator 10 are provided. 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 photoconductor 1 via the grid plate 13.

Reference numeral 14 denotes an exposure light beam of image data emitted from the exposure optical system 6. In the case of a laser printer, the exposure light beam 14 is controlled by a signal from a host computer (not shown), and a plurality of exposure light beams corresponding to specific components among a plurality of predetermined color components are formed on the photoreceptor 1. An electrostatic latent image is formed.

The developing units 7B, 7Y, 7M, 7C for the respective colors are removably stacked one below the other in predetermined storage portions provided in the body of the machine, and the developing units 7B, 7Y, 7M, 7M,
7C has the same configuration except for the toner. For example, the black (B) developing device 7B has an agitator 15, a toner supply roller 16, a developing roller 17, a doctor blade 18, and a recovery sheet 19 as shown in FIGS. Reference numeral 15 denotes an agitator which is bent and formed in a rectangular shape by a wire or the like and whose both ends are rotatably supported. The agitator 15 draws a locus of a circle shown by a dashed line in a clockwise direction with the rotation of the toner supply roller 16,
The toner supplied into the developing device 7B is stirred to prevent coagulation, and the toner is conveyed to the toner supply roller 16. Reference numeral 16 denotes a toner replenishing roller which is rotatably supported at both ends by a toner hopper of the developing device 7B, and replenishes the toner agitated and conveyed by the agitator 15 to the surface of the developing roller 17 which is driven to rotate counterclockwise. The toner replenishing roller 16 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 silicone is formed in a layer on the outer peripheral surface thereof. It is supported and rotated counterclockwise. The developing roller 17 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. The developing roller 17 is rotatably supported at both ends of the developing device 7B and is driven to rotate counterclockwise. doing. The doctor blade 18 is made 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 16 to form a doctor blade 18 on the outer peripheral surface of the developing roller 17. To form a thin layer state.

The intermediate transfer body unit 8 includes a belt-like intermediate transfer body belt 20 made of a conductive resin or the like, and three intermediate transfer body belt supporting / conveying rollers 21 for adjusting and supporting the intermediate transfer body belt 20. 22, and an intermediate transfer roller 24 arranged to face the photoconductor 1 with the intermediate transfer belt 20 interposed therebetween to transfer the toner image on the photoconductor 1 to the intermediate transfer belt 20. .

Here, the surface circumference of the intermediate transfer belt 20 is designed to be equal to the surface circumference of the photoreceptor 1. Reference numeral 25 denotes an intermediate transfer belt cleaning device for scraping residual toner on the intermediate transfer belt 20, and is separated from the intermediate transfer belt 20 while a synthetic image is formed on the intermediate transfer belt 20. , Contact only when used for cleaning. Reference numeral 26 denotes a paper cassette that stores paper 27.

The paper 27 is sent out one by one from a paper cassette 26 to a paper transport path 29 by a paper feed roller 28. Reference numeral 30 denotes a sheet 27 temporarily in order to match the position of the sheet 27 with the composite image formed on the intermediate transfer belt 20.
Is a registration roller for stopping and waiting for a stop, and is in pressure contact with the driven roller 31. Reference numeral 32 denotes a paper transfer roller for transferring the composite image formed on the intermediate transfer belt 20 to the paper 27, and rotates in contact with the intermediate transfer belt 20 only when the composite image is transferred to the paper 27.

Reference numeral 33 denotes a heat roller 3 having a heat source therein.
4 and a pressure roller 35.
The composite image transferred to the heat roller 34 and the pressure roller 3
5, the toner image is fixed on the sheet 27 by pressure and heat with the rotation of the sheet 5 to form a color image.

Reference numerals 36 and 37 denote paper discharge roller pairs provided on the downstream side of the fixing device 33. Reference numeral 38 denotes a paper discharge tray provided on the side of the machine body, which is rotatably supported by a paper discharge tray shaft 39.

The operation of the developing device of the conventional image forming apparatus configured as described above will be described below. First, a high voltage is applied to the charging line 11 in the charger 5 connected to the high-voltage power supply to cause corona discharge, thereby uniformly charging the surface of the photoconductor 1 to about -500v to -650v.

Next, the photosensitive member 1 is rotated in the direction of arrow A by a driving device (not shown) to uniformly charge the photosensitive member 1.
When a predetermined color in a plurality of color components, for example, an exposure light beam 14 such as a laser beam corresponding to an image of black (B) is irradiated on the surface of the photosensitive member 1, the irradiated portion on the photoconductor 1 loses its charge and becomes static. An electrostatic latent image is formed. On the other hand, in the developing device 7B in which the black developer contributing to the development is stored, the separation / contact means is operated by a color selection signal from a host computer (not shown), and thereby comes into contact with the photosensitive member 1.

At this time, in the developing unit 7B, the toner is conveyed onto the toner supply roller 16 by the agitator 15. The toner conveyed onto the toner supply roller 16 is frictionally charged by the contact between the toner supply roller 16 and the developing roller 17 and adheres to the surface of the developing roller 17 by electrostatic force. The attached toner layer is conveyed to the pressure contact portion with the doctor blade 18 while being carried on the surface of the developing roller 17 by the rotation of the developing roller 17. The transported toner is subjected to a frictional action between the developing roller 17 and the doctor blade 18, and the amount of triboelectric charge is further increased to form a uniform thin layer state. The toner that has passed through the doctor blade 18 is transported in a thin layer while maintaining the above-mentioned triboelectric charge amount to a contact position (developing area) with the photoconductor 1. At this contact position, the developing roller 17
When a potential difference is applied between the photoconductor 1 and the toner, the toner is transferred and adhered to the electrostatic latent image formed on the photoconductor 1 to form a visible image, and the development is completed. Further, the toner that has not been transferred and adhered to the photoreceptor 1 passes between the recovery sheet 19 and the developing roller 17 in a thin layer state, is scraped off by the toner replenishing roller 16, and is returned to the developing device 7B again. It is. The developing device 7B that has completed the development is moved by the separating / contacting means 60 from the contact position with the photoconductor 1 to the separated position. While the developing unit 7B is developing, the other developing units 7Y, 7M, and 7C are separated from the photosensitive member 1.

Next, when the color of, for example, cyan (C) is selected, the developing unit 7C is brought into contact with the photosensitive member 1 and starts developing cyan. In the case of a copier or a printer using four colors, the developing operation is sequentially repeated four times to superimpose the toner images of four colors (B, C, M, Y) on the intermediate transfer belt 20 to form a composite image.

The composite image formed in this way is applied to a paper transfer roller 32 with a high pressure and is collectively transferred to the paper 27 sent from the paper cassette 26 along the paper transport path 29 by the pressure. The color image is formed by fixing the heat roller 34 and the pressure roller 35 between the heat roller 34 and the pressure roller 35. The sheet 27 that has passed through the fixing device 33 passes through a pair of discharge rollers 36 and 37 and is discharged to a discharge tray 38.

In FIG. 13, the amount of toner transported from the inside of the toner hopper to the toner replenishing roller 16 by the agitator 15 changes the amount of toner consumed in development, that is, the electrostatic latent image formed on the photosensitive member 1 into a visible image. It must be the same as the toner amount. Therefore, in order to regulate the amount of toner transported to the toner supply roller 16, the developing units 7B, 7Y, 7M,
The housing inside 7 </ b> C protrudes from above and below.
Regulates the amount of toner supplied to the printer. Agitator 1
The number of rotations of 5 is designed to be の of the number of rotations of the developing roller 17. Therefore, the amount of toner supplied to the toner replenishing roller 16 depends on the opening area of the toner conveyance amount regulating slit 40 and the rotation speed and shape of the agitator 15.

[0019]

However, in the conventional example described above, in this image forming apparatus system, the toner amount Md consumed in the development is determined by the respective developing units 7B and 7B.
In one contact of 7Y, 7M, 7C, about 0 g ≦ Md ≦
0.6 g. Therefore, in order to regulate the amount corresponding to the toner amount Md by the toner conveyance amount regulating slit 40, the opening is a minute space. However, toner blocking occurs in the minute space during environmental fluctuations or long-time use, and image quality deterioration such as image blurring due to insufficient toner supply to the toner supply roller 16 has been caused.

When a small amount of toner is continuously consumed, the amount of toner transported by the agitator becomes excessive, and a space surrounded by the doctor blade 18, the developing roller 17, the toner replenishing roller 16, and the toner transport amount regulating slit 40 is provided. E causes blocking of the toner, and the doctor blade 18 causes the developing roller 17 to be blocked by the blocking toner.
In some cases, the pressure is pushed up in a direction opposite to the pressing direction, resulting in a value deviating from an appropriate pressure.

Further, there is a method in which a toner amount detection sensor is provided in the space E and the toner is supplied from the inside of the toner hopper to the toner supply roller 16 in accordance with the detected amount. There was a problem that was inevitable.

Therefore, in order to solve the above-mentioned conventional problems, the present invention stabilizes the amount of toner supplied from a toner hopper, and further, in an apparatus such as a color image forming apparatus, in which a developing device is stacked for each color. In order to provide a developing device for an image forming apparatus which can achieve a cost reduction with a simple compact structure even when a plurality of agitators are provided in a toner hopper because the image forming apparatus main body and the developing device must be kept thin. With the goal.

[0023]

In order to achieve the above object, a developing device according to the present invention provides a toner conveying member for supplying a toner from a toner hopper containing toner to a toner replenishing means with a flat or curved toner conveying surface. And the number of rotations of the toner conveying member and the number of rotations of the developing roller.
Is 1/4 ≦ (number of rotations of toner conveying member) / (development
(The number of rotations of the roller) ≦ 1 .

[0024]

[0025] is obtained by constituting the toner conveying member which is closest to at least a toner supplying means in a plane in the developing device in which a plurality disposed toner conveying member.

Further, a projection is provided on the toner conveying surface of the toner conveying member closest to at least the toner supplying means.

Further, a through hole is provided in addition to the protrusion on the toner conveying surface of the toner conveying member closest to at least the toner supplying means.

[0028]

According to the present invention, the toner in the toner hopper can be circulated without stagnation, the toner can be supplied stably without inducing toner blocking, and the fluctuation of the toner layer thickness on the developing roller can be prevented. it can. In addition, since a special device is not required, even a configuration including a plurality of agitators can suppress an increase in cost with a simple compact structure.

[0029]

【Example】

(Embodiment 1) Hereinafter, a developing device of an image forming apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of an image forming apparatus provided with a developing device according to a first embodiment of the present invention, FIG. 2 is a side view of a developing device of the image forming apparatus according to the first embodiment of the present invention, and FIG. FIG. 2 is a perspective view of a developing device of the image forming apparatus according to the first embodiment of the present invention.

Here, the same reference numerals are given to the same constituent members as those of the developing device of the conventional image forming apparatus, and the detailed description is omitted.

Reference numeral 41 depicts the trajectory of a circle indicated by a dashed line in the clockwise direction along with the rotation of the toner replenishing roller 16 to agitate the toner and prevent toner from entering into the developing unit 7B and replenish the toner. The toner conveying surface 71 is formed integrally with a shaft ( shaft ) 70 that supports the agitator 41 in a planar shape using resin. Also, doctor blade 18,
In a space E surrounded by the developing roller 17 and the toner replenishing roller 16, the toner replenished onto the developing roller 17 by the toner replenishing roller 16 is scraped off by the toner thinning action of the doctor blade 18, and the toner E is easily returned to the toner hopper. It is formed as wide as possible.

The operation of the developing device of the image forming apparatus according to the first embodiment of the present invention configured as described above will be described below. First, the charger 5 connected to the high-voltage power supply
A high voltage is applied to the charged wire 11 in the inside to cause corona discharge,
The surface of the photoconductor 1 is uniformly charged to about -500v to -650v.

Next, the photosensitive member 1 is rotated in the direction of arrow A by a driving device (not shown) to uniformly charge the photosensitive member 1.
When a predetermined color in a plurality of color components, for example, an exposure light beam 14 such as a laser beam corresponding to an image of black (B) is irradiated on the surface of the photosensitive member 1, the irradiated portion on the photoconductor 1 loses its charge and becomes static. An electrostatic latent image is formed. On the other hand, in the developing device 7B in which the black developer contributing to the development is stored, the separation / contact means is operated by a color selection signal from a host computer (not shown), and thereby comes into contact with the photosensitive member 1.

At this time, in the developing device 7B, the toner is conveyed onto the toner supply roller 16 by the agitator 41. The toner conveyed onto the toner supply roller 16 is frictionally charged by the contact between the toner supply roller 16 and the developing roller 17 and adheres to the surface of the developing roller 17 by electrostatic force. The attached toner layer is conveyed to the pressure contact portion with the doctor blade 18 while being carried on the surface of the developing roller 17 by the rotation of the developing roller 17. The transported toner is subjected to a frictional action between the developing roller 17 and the doctor blade 18, and the amount of triboelectric charge is further increased to form a uniform thin layer state. The toner that has passed through the doctor blade 18 is transported in a thin layer while maintaining the above-mentioned triboelectric charge amount to a contact position (developing area) with the photoconductor 1. At this contact position, the developing roller 17
When a potential difference is applied between the photoconductor 1 and the toner, the toner is transferred and adhered to the electrostatic latent image formed on the photoconductor 1 to form a visible image, and the development is completed. Further, the toner that has not been transferred and adhered to the photoreceptor 1 passes between the recovery sheet 19 and the developing roller 17 in a thin layer state, is scraped off by the toner replenishing roller 16, and is returned to the developing device 7B again. It is. The developing device 7B, which has completed the development, is moved from the contact position with the photoconductor 1 to the separated position by the separating means. While the developing unit 7B is developing, the other developing units 7Y, 7M, and 7C are separated from the photosensitive member 1.

Next, when, for example, the color of cyan (C) is selected, the developing unit 7C is brought into contact with the photosensitive member 1 and starts developing cyan. In the case of a copier or a printer using four colors, the developing operation is sequentially repeated four times to superimpose the toner images of four colors (B, C, M, Y) on the intermediate transfer belt 20 to form a composite image.

The composite image thus formed is applied to a paper transfer roller 32 with a high pressure, and is collectively transferred to the paper 27 sent from the paper cassette 26 along the paper transport path 29 by the pressure. The color image is formed by fixing the heat roller 34 and the pressure roller 35 between the heat roller 34 and the pressure roller 35. The sheet 27 that has passed through the fixing device 33 passes through a pair of discharge rollers 36 and 37 and is discharged to a discharge tray 38.

In FIG. 2, since the rotation speed of the agitator 41 is set within a predetermined range (to be described later), the toner agitating action in the toner hopper acts more than the toner feeding action to the toner supply roller 16. become. Furthermore,
In order to emphasize this toner stirring action, a toner transport surface 73 provided on a shaft 72 like an agitator 42 shown in FIG.
The toner may be formed into a curvature shape having a center of curvature on the side. In this case, the flow of the toner returning from the space E to the toner hopper is promoted, and the stagnation and blocking of the toner not only in the toner hopper but also in the developing device 7B are prevented. It will also prevent it.
Here, regarding the rotation speed of the agitator 41, if the rotation speed is extremely low, the effect of promoting the toner flow described above is reduced, and the stagnation and blocking of the toner occur, and the developing roller 1
7, the toner layer thickness becomes multilayer. Conversely, when the rotation speed is increased, the structure forming the toner is destroyed, the original toner characteristics are not satisfied, and the dot reproducibility on the image is disturbed, and development loss and transfer loss are caused. In addition, the consumption rate increases and the life is shortened. Therefore, the ratio of the number of rotations of the developing roller 17 and the agitator 41 obtained from the experiment (the agitator 4
1 / the number of rotations of the developing roller 17 = R) and the number of rotations of the developing roller 1 after passing through the doctor blade 18 before and after development.
FIG. 5 shows the relationship between the toner amount difference per unit area above (toner amount per unit area after development−toner amount per unit area before development = S). Since the range of S where the density difference is not conspicuous on the output image is ± 0.2 mg / cm ² , the optimum range of R is preferably ≦≦ R ≦ 1.

(Embodiment 2) Next, a developing device of an image forming apparatus according to a second embodiment of the present invention will be described with reference to the drawings.

Here, the configuration of the image forming apparatus main body according to the second embodiment of the present invention is the same as that of the image forming apparatus main body according to the above-described first embodiment, and the description thereof will be omitted.

FIG. 6 is a side view of the developing device of the image forming apparatus according to the second embodiment of the present invention, and FIG. 7 is a perspective view of the developing device of the image forming apparatus according to the second embodiment of the present invention.
Note that the same components as those of the developing device of the image forming apparatus according to the first embodiment of the present invention are given the same reference numerals, and detailed description thereof will be omitted.

In FIG. 6, reference numeral 43 denotes the toner supply roller 1
With the rotation of 6, the trajectory of the circle shown by the one-dot chain line is drawn clockwise, and the agitator that stirs the toner in order to prevent the toner charged in the developing device 7B from condensing and conveys the toner to the toner supply roller 16 The toner conveying surface is integrally formed of resin and a shaft portion that supports the agitator 43 in a planar shape. The agitators 44, 45, and 46 respectively draw the trajectories of the circles indicated by the dashed lines in the clockwise direction as they rotate, stir the toner in order to prevent the toner charged in the developing device 7B from aggregating, and transfer the toner to the front agitator. (44 goes to 43, 45 goes to 44, 46 goes to 45
F) The agitator to be transported, and the toner transport surface may be flat or linear such as a wire. Ideally, a flat toner conveying surface is preferable in order to promote the circulation of the toner in the toner hopper. If there is, the agitators 44, 45, shown in FIG.
There is a possibility that the rotational load torque of 46 will increase and step out and lock will occur in the agitator rotation drive gear train 47.

The operation of the developing device of the image forming apparatus according to the second embodiment of the present invention configured as described above will be described below. The image forming apparatus main body according to the above-described first embodiment of the present invention will be described. The description of the same operation as the operation of the developing device and the operation of the developing device will be omitted.

Since the agitator 43 operates in the same manner as in the first embodiment of the present invention, the same effects can be obtained. However,
Due to the configuration of the image forming apparatus, a thin developing device 7B as shown in FIG.
In, the agitators 43, 44, 45, 46 are disposed, so that attention must be paid to the rotation speed of the agitators 44, 45, 46. It is, for example, an agitator 44
In order to prevent interference between adjacent agitators such as the agitator 45 and the agitator 45, each agitator (43, 4
4, 45, 46) to the integral multiple and (1 / integer)
Must be set to double. In addition, when the agitators 44, 45, and 46 whose toner conveying surfaces are not formed in a planar shape rotate at a high speed, the toner is excessively conveyed onto the toner replenishing roller 16, so that the rotational speed of the agitator 43 needs to be reduced. There is. In the developing device according to the second embodiment of the present invention, the developing roller 17, the agitator 43, the agitator 4
4. The rotational speed ratios of the agitator 45 and the agitator 46 are respectively set to 1: 1/2: １ ／: １ ／: １ ／.

(Embodiment 3) Next, a developing device of an image forming apparatus according to a third embodiment of the present invention will be described with reference to the drawings.

Here, the configuration of the image forming apparatus main body according to the third embodiment of the present invention is the same as that of the image forming apparatus main body according to the above-described first embodiment, and therefore the description thereof is omitted.

FIG. 8 is a side view of the developing device of the image forming apparatus according to the third embodiment of the present invention, and FIG. 9 is a perspective view of the developing device of the image forming apparatus according to the third embodiment of the present invention.
Note that the same components as those of the developing device of the image forming apparatus according to the second embodiment of the present invention are given the same reference numerals, and detailed description thereof will be omitted.

In FIG. 8, reference numeral 48 denotes the toner supply roller 1.
With the rotation of 6, the trajectory of the circle shown by the one-dot chain line is drawn clockwise, and the agitator that stirs the toner in order to prevent the toner charged in the developing device 7B from condensing and conveys the toner to the toner supply roller 16 A projection 49 is provided on the flat toner conveying surface. The side cross section of the agitator 48 is formed in an L shape perpendicular to the toner conveying surface, but this angle is not particularly limited. It is considered that the position of the protrusion 49 is closer to the outer periphery than the rotation locus, but the position and the height with respect to the toner conveying surface are not particularly limited.

The operation of the developing device of the image forming apparatus according to the third embodiment of the present invention configured as described above will be described below. The main body of the image forming apparatus according to the above-described second embodiment of the present invention will be described. The description of the same operation as the operation of the developing device and the operation of the developing device will be omitted.

The agitator 48 operates in the same manner as in the first embodiment of the present invention, so that the same effect can be obtained. More specifically, the agitator 48 promotes the flow of the toner returning from the space E into the toner hopper. However, the effect of preventing toner stagnation and blocking in the developing device 7B is improved as compared with the developing device of the image forming apparatus according to the second embodiment of the present invention.

(Embodiment 4) Next, a developing device of an image forming apparatus according to a fourth embodiment of the present invention will be described with reference to the drawings.

Here, the configuration of the image forming apparatus main body according to the fourth embodiment of the present invention is the same as that of the image forming apparatus main body according to the above-described first embodiment, and the description thereof will be omitted.

FIG. 10 is a side view of a developing device of an image forming apparatus according to a fourth embodiment of the present invention, and FIG.
FIG. 4 is a perspective view of a developing device of the image forming apparatus according to the embodiment. Note that the same components as those of the developing device of the image forming apparatus according to the third embodiment of the present invention are given the same reference numerals, and detailed description thereof will be omitted.

In FIG. 10, the reference numeral 50 indicates a clockwise trajectory of a circle shown by a dashed line with the rotation of the toner replenishing roller 16 and agitates the toner in the developing device 7B to prevent coagulation of the toner. The agitator transports the toner to the toner replenishing roller 16. The projection 49 and the through hole 51 are provided on the planar toner transport surface.
The shape, position, and number of the through holes 51 are not particularly limited.

The operation of the developing device of the image forming apparatus according to the fourth embodiment of the present invention configured as described above will be described below. The image forming apparatus main body according to the above-described third embodiment of the present invention will be described. The description of the same operation as the operation of the developing device and the operation of the developing device will be omitted.

Since the agitator 50 operates in the same manner as the first embodiment of the present invention, the same effect can be obtained. However, as described above, for example, when the toner is biased only on one side of the developing device 7B due to transportation or the like. FIG. 1 shows that the rotational load torque of the agitators 44, 45 and 46 increases when the toner transport surface is flat.
Step-out and locking may occur in the agitator rotation drive gear train 47 shown in FIG. Therefore, if a plurality of through holes 51 are provided in the toner conveying surface, the agitators 44, 4
5, 46 increase in rotational load torque can be suppressed,
Step-out and locking in the agitator rotation drive gear train 47 can be prevented. Regarding the circulation of the toner, the protrusion 49 is provided, so that stagnation and blocking of the toner do not occur.

[0056]

As described above, according to the present invention, the toner in the toner hopper can be circulated without stagnation, the toner can be supplied stably without inducing toner blocking, and the toner layer on the developing roller can be stably supplied. Thickness fluctuation can be prevented. In addition, since a special device is not required, an excellent developing device that can suppress a rise in cost with a simple compact structure can be realized even with a configuration including a plurality of agitators.

[Brief description of the drawings]

FIG. 1 is a side view of an image forming apparatus including a developing device according to a first embodiment of the present invention.

FIG. 2 is a side view of a developing device of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a developing device of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a curvature-shaped agitator of the developing device of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a ratio between the rotation speeds of a developing roller and an agitator of a developing device of an image forming apparatus according to a first embodiment of the present invention, and a difference between a toner amount per unit area on a developing roller after passing a doctor blade before and after development. Relationship diagram

FIG. 6 is a side view of a developing device of an image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a developing device of an image forming apparatus according to a second embodiment of the present invention.

FIG. 8 is a side view of a developing device of an image forming apparatus according to a third embodiment of the present invention.

FIG. 9 is a perspective view of a developing device of an image forming apparatus according to a third embodiment of the present invention.

FIG. 10 is a side view of a developing device of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a perspective view of a developing device of an image forming apparatus according to a fourth embodiment of the present invention.

FIG. 12 is a side view of an image forming apparatus provided with a conventional developing device.

FIG. 13 is a side view of a developing device in a conventional image forming apparatus.

FIG. 14 is a perspective view of a developing device in a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Photoconductor belt support conveyance roller 3 Photoconductor belt support conveyance roller 4 Photoconductor belt support conveyance roller 5 Charger 6 Exposure optical system 7 Developing device 8 Intermediate transfer body unit 9 Photoconductor cleaning device 10 Static eliminator 11 Charge line DESCRIPTION OF SYMBOLS 12 Shield plate 13 Grid plate 14 Exposure light beam 15 Agitator 16 Toner supply roller 17 Developing roller 18 Doctor blade 19 Recovery sheet 20 Intermediate transfer member belt 21 Intermediate transfer member belt support and conveyance roller 22 Intermediate transfer member belt support and conveyance roller 23 Intermediate transfer member belt Supporting and Conveying Roller 24 Intermediate Transfer Roller 25 Intermediate Transfer Body Belt Cleaning Device 26 Paper Cassette 27 Paper 28 Feeding Roller 29 Paper Conveying Path 30 Registration Roller 31 Follower Roller 32 Paper Transfer Roller 33 Fixer 34 Heat Roller 35 Pressure roller 36 Discharge roller pair 37 Discharge roller pair 38 Discharge tray 39 Discharge tray shaft 40 Toner transport amount regulating slit 41 Agitator 42 Agitator 43 Agitator 44 Agitator 45 Agitator 46 Agitator 47 Agitator rotation drive gear train 48 Agitator 49 Projection Reference Signs List 50 agitator 51 through hole 60 separation / contact means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Ueoka 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Nobuo Kishiyama 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Person Yoshiyuki Okamura 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-330471 (JP, A) JP-A-3-267963 (JP, A) JP-A-3-3 140982 (JP, A) JP-A-8-106208 (JP, A) JP-A-5-119621 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/08

Claims (5)

(57) [Claims] A developing roller which is formed in a roller shape and rotatably carries toner on its surface; and a doctor blade which comes into contact with said developing roller and adheres and charges the toner on said developing roller to regulate the layer thickness of the toner. A toner replenishing means for replenishing the developing roller with toner, a toner hopper for storing the toner, and a diametrical piece of a rotating shaft for supplying the toner by rotation from the toner hopper to the toner replenishing means.
The toner conveying surface provided only on one side has a plate-shaped toner conveying member, and the rotation direction of the toner conveying member is
When the tip of the conveying member is closest to the developing roller
At the same time , the ratio of the rotation speed of the toner conveying member to the rotation speed of the developing roller is set to 1
/ 4 ≦ (number of rotations of the toner conveying member) / (number of rotations of the developing roller) ≦ 1. 2. The developing device according to claim 1, wherein a toner conveying surface of said toner conveying member is flat. 3. The developing device according to claim 1, wherein a plurality of said toner conveying members are provided, and said toner conveying member closest to said toner replenishing means is a flat surface. 4. The developing device according to claim 3, wherein a projection is provided on a toner conveying surface of the toner conveying member closest to the toner replenishing means among the plurality of toner conveying members. 5. The developing device according to claim 4, wherein a through-hole is provided in a toner conveying surface of said toner conveying member having a projection on said toner conveying surface among said plurality of toner conveying members.