JP2000075638A - Developing device, developing cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent coarse-grain toner from being produced and to prevent the toner from leaking due to sticking to developer regulation member caused by turbulence of a photographed image or movement of the coarse-grain toner by securing a clearance between the end surface of a developer supply member and a developing container. SOLUTION: A toner coating roller 29YA is rotatably supported by a developing frame body 29b and the clearance 100 being 0.5 to 2.0 mm is secured at both ends of the roller 29YA in the longitudinal direction, for example. Thus, the roller 29YA can rotate without being rubbed with the frame body 29b. Therefore, the coarse-grain toner is prevented from being produced at both ends of the roller 29YA in the longitudinal direction. Besides, the toner retained in a toner receiving chamber is made to flow and returned to a toner housing chamber from the clearance 100. Thus, the toner is prevented from being leaked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer, a developing device used in the electrophotographic image forming apparatus, and a developing cartridge including at least the developing device. .

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, an electrostatic latent image formed on an image carrier is visualized as a toner image by a developing device.

As one of such developing devices, various dry single-component developing devices have been proposed and put into practical use. However, it is difficult for any developing device to form a thin layer of toner, which is a one-component developer, on a developer carrier.

However, at present, there is a demand for improvements in image resolution, sharpness, etc., and research on a method and an apparatus for forming a thin layer of toner is indispensable. Proposed.

For example, as described in Japanese Patent Application Laid-Open No. 54-43038, an elastic blade as a regulating member made of a material such as metal or rubber is brought into contact with a developing roller as a developer carrying member. By restricting the toner by passing it between the contact portions between the elastic blade and the developing roller, a thin layer of the toner is formed on the developing roller, and sufficient tribo is given to the toner at the contact portions. Things.

In this case, when the non-magnetic toner is regulated by the elastic blade, a toner supply member for supplying the toner onto the developing roller is separately required. This is because in the case of a magnetic toner, the developer on the developing roller can be supplied by the magnetic force of a magnet in the developing roller, but in the case of a non-magnetic toner, the toner cannot be supplied by the magnetic force.

Therefore, a developing device 50 as shown in FIGS. 6 and 7 has been proposed. In this conventional developing device 50, a developing container 54 containing a non-magnetic toner 53 as a one-component developer is provided at a position on the rotationally upstream side of a developing roller 52 which is a developer carrier with respect to a developing blade 51 which is a regulating member. An elastic roller 55 which is a toner supply member using a polyurethane foam, a sponge or the like, or a fur brush, which comes into contact with the roller 55, is provided, and the toner 53 is supplied onto the developing roller 52 by rotating in the direction of arrow D. .

The toner 53 supplied onto the developing roller 52 is supplied to the developing blade 5 by the rotation of the developing roller 52.
The toner is sent to a contact portion between the developing roller 1 and the developing roller 52 to be thinned, and is used for developing an electrostatic latent image on the photoconductor 1.

The toner 53 remaining without being consumed in the development on the developing roller 52 is peeled off by the applying roller 55, and new toner 53 is supplied to the developing roller 52 by the applying roller 55 as described above. The above operation is repeated.

In this case, when the developing roller 52 is made of a metal material, the developing blade 51 made of a thin metal plate is not preferable in terms of abrasion of the developing roller. It is necessary to use a rubber material such as urethane or silicon.

[0011]

However, in the conventional developing apparatus as described above, in recent years, in order to pursue high image quality, toner having a high particle size and a low viscosity, that is, penetrating into any gaps, has been developed. The use of easy-to-use toner has increased.

The toner 53 having such properties is supplied from the developing container 54 to the developing roller 5 via the application roller 55.
2 and enters the rubbing surface between the application roller 55 and the developing device frame 57 that rotatably supports the coating roller 55, generates coarse toner, and causes the developing blade 51 to disturb the developed image and to move the coarse toner. To the toner, and may cause toner leakage.

The toner regulated by the developing blade 51 and not applied to the developing roller 52 or the toner conveyed by the applying roller 55 and not applied to the developing roller 52 is opened by the developing roller 52 and the developer seal 56. Is packed in the space of the sealed toner receiving opening due to excessive supply, the internal pressure is increased, and there is a possibility that toner leakage may occur from a weak part due to the configuration of the developer seal 56 to the outside.

Accordingly, an object of the present invention is to prevent the generation of coarse-grained toner near the support portion of the developer supply member even when a toner having a high particle size and a low viscosity is used, and to prevent disturbance of a developed image A developing device capable of preventing toner leakage due to fusion of toner to the developer regulating member due to movement of toner, and preventing toner leakage due to occurrence of packing due to excessive supply of toner, a developing cartridge including the developing device, An object of the present invention is to provide an image forming apparatus including the developing device or the developing cartridge.

[0015]

The above object is achieved by a developing device, a developing cartridge and an image forming apparatus according to the present invention. In summary, the present invention provides a developing container for storing a developer, a developer carrier rotatably supported at an opening of the developing container and carrying the developer, and rotatably supported by the developing container. A developing device having a developer supply member for supplying a developer to the developer carrier, wherein a clearance is secured between an end surface of the developer supply member and the developing container. Device.

According to another aspect of the present invention, there is provided a developer container for storing a developer, a developer carrier rotatably supported by an opening of the developer container, and carrying and transporting the developer; A developing cartridge having at least a developer supply member rotatably supported and supplying a developer to the developer carrier, wherein the developer supply member is detachably mounted on an image forming apparatus main body. A clearance is secured between the end surface of the developing container and the developing container.

According to another aspect of the present invention, there is provided a developer container for storing a developer, a developer carrier rotatably supported by an opening of the developer container for carrying and transporting the developer, An image forming apparatus including a developing device rotatably supported by a container and having a developer supply member for supplying a developer to the developer carrier; An image forming apparatus characterized in that a clearance is secured.

In the above invention, the clearance is preferably 0.5 to 2.0 mm. In addition, it is preferable that the clearance is secured by positioning the shaft of the developer supply member against at least one bearing member.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developing device, a developing cartridge and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 [Overall Description of Image Forming Apparatus] First, the overall configuration of a color image forming apparatus will be schematically described with reference to FIG. FIG. 1 shows a color laser printer which is an embodiment of a color image forming apparatus.

As shown in FIG. 1, the color laser printer includes an image carrier (photosensitive drum) 2 which rotates at a constant speed.
1 and a fixed black developing device (also referred to as “developing device”) 30
B, and three rotatable color developing devices (yellow developing device 29Y, magenta developing device 29M, cyan developing device 29C,
An image forming unit composed of:
Further, the transfer material 19 which has been developed in the image forming unit and holds the multi-transferred color image, and which has been fed from the transfer material feeding unit.
Is provided with an intermediate transfer member 33 for further transferring the image. The transfer material 19 on which the color image has been transferred from the intermediate transfer body 33 is conveyed to the fixing unit 44 to be fixed on the transfer material 19, and the discharge roller 16,
It is discharged to the discharge section 49 on the upper surface of the apparatus by 17 and 18.

The three color developing units and the fixed black developing unit are configured to be individually attachable and detachable as a developing cartridge to the printer main body.

Next, the configuration of each section of the image forming apparatus will be described in detail in order.

[Image Carrier Unit] Image Carrier Unit 2
Numeral 0 indicates that the image carrier 21 and the container 22 of the cleaning device also serving as a holder for the image carrier 21 are integrally formed. The image carrier unit 20 is detachably supported by the printer main body, and is configured so that the unit can be easily replaced according to the life of the image carrier 21.

The image carrier 21 according to this embodiment has a diameter 62
mm of an aluminum cylinder is coated with an organic photoconductor layer on the outside thereof.
It is supported rotatably.

On the periphery of the image carrier 21, a cleaner blade 23 and a primary charging means 24 are arranged.
By transmitting the driving force of a driving motor (not shown) to one end of the image bearing member 1, the image carrier 21 is rotated counterclockwise in the figure according to the image forming operation.

[Charging Means] The primary charging means 24 is a conductive roller using a contact charging method. The charging roller is brought into contact with the image carrier 21, and a voltage is applied to the conductive roller 24 to carry the image. It charges the surface of the body 21 uniformly.

[Exposure Means] Exposure to the image carrier 21 is performed from the scanner unit 25. That is, when an image signal is given to the laser diode, the laser diode irradiates the polygon mirror 26 with an image corresponding to the image signal.

The polygon mirror 26 is a scanner motor 26
a, the image light reflected by the polygon mirror 26 selectively exposes the surface of the image carrier 21 rotating at a constant speed via the imaging lens 27 and the reflection mirror 28, and as a result, the image carrier An electrostatic latent image is formed on 21.

[Developing Means] The developing means serves to make each of the yellow (Y), magenta (M), cyan (C) and black (B) colors as described above in order to visualize the electrostatic latent image. Three rotary developing devices 29Y, 29M, 29 that enable development
C and one black developing unit 30B.

The black developing device 30B is a fixed developing device. A developing roller 30BS, which is a developer carrying member, is provided at a position facing the image carrying member 21 at a minute interval (300 μm) with respect to the image carrying member 21.
m) and a developing bias is applied to the developing roller 21BS, so that the surface of the image carrier 21 is visualized as a toner image using black toner.

The black developing device 30B sends the toner (developer) in the container to the developing roller 30BS, which is a developer carrier, by a feeding mechanism, and the application blade 30BB pressed against the outer periphery of the developing roller 30BS in a clockwise direction in FIG. A thin layer of toner is applied to the outer periphery of the developing roller 30BS rotating at a time, and a charge is applied to the toner (friction charging).

Three rotary developing units 29Y, 29M, 29C
Each of the cartridges contains toner corresponding to 6000 pages (A4, 5% printing), and is detachably held as a developing cartridge on a developing rotary 32 that rotates about an axis 31.

At the time of image formation, each developing device is rotated around the shaft 31 while being held by the developing rotary 32, a predetermined developing device is stopped at a position facing the image carrier 21, and the developing roller is further moved. A minute interval (3
(Approximately 00 μm), and a visible image is formed corresponding to the electrostatic latent image on the image carrier 21.

When forming a color image, one of the intermediate transfer members 33
The developing rotary 32 rotates with each rotation, and the yellow developing device 2
9Y, a magenta developing unit 29M, a cyan developing unit 29C, and then a black developing unit 30B are developed in this order.

FIG. 2 shows a state in which the yellow developing unit 29Y is positioned and stationary at a position facing the image carrier unit 20. The yellow developing device 29Y sends the toner in the container frame 29a to an application roller 29YA serving as a developer supply member by a feeding mechanism 29YT, and the application roller 29YA rotating clockwise in the drawing and the outer periphery of the development roller 29YS serving as a developer carrier. A developing blade 29YB as a developer regulating member pressed against the developing roller 29YB applies a thin layer of the developer to the outer periphery of the developing roller 29YS rotating clockwise in the drawing, and applies a charge to the toner (friction charging).

The toner is developed on the image carrier 21 in accordance with the latent image by applying a developing bias to the developing roller 29YS facing the image carrier 21 on which the latent image is formed.

Magenta developing device 29M, cyan developing device 29
For C, developer development is performed by the same mechanism as described above.

Each of the rotary developing devices 20Y, 20M, 20C
When each developing device is rotated to the developing position, each developing roller is connected to a high-voltage power supply for each color development provided in the printer main body and a driving source, and a voltage is sequentially and selectively applied for each color development. The drive is applied and transmitted.

[Intermediate Transfer Body] The intermediate transfer body 33 transfers the toner image on the image carrier 21 visualized by each developing device four times (each of four colors of Y, M, C, and B) during a color image forming operation. (Image), the image carrier 21
And rotates clockwise in FIG. Further, the intermediate transfer body 33 that has received the multiple transfer transfers the transfer material 2 between the transfer rollers 34 to which a voltage is applied, and conveys the developer images of the respective colors on the intermediate transfer body 33 onto the transfer material 2 at the same time. I do.

The intermediate transfer member 33 according to the present embodiment has a diameter of 1
The outer circumference of an 86 mm aluminum cylinder 35 is covered with an elastic layer 36 of medium resistance sponge, medium resistance rubber or the like. The intermediate transfer member 33 is rotatably supported, and is rotated by being driven by a gear (not shown) fixed integrally.

[Cleaning Unit] The cleaning unit is configured to transfer the toner visualized on the image carrier 21 by the developing unit to the intermediate transfer member 33, and then transfer the toner to the image carrier 21.
This is for cleaning the toner remaining on the top. The removed toner that has been cleaned is stored in the cleaner container 22. The amount of the removed toner stored in the container 22 does not fill the container 22 earlier than the life of the image carrier 21.
Therefore, when the life of the image bearing member 21 is replaced, the container 22 is simultaneously replaced.

[Paper Feeding Unit] The paper feeding unit feeds the transfer material 19 to the image forming unit, and includes a cassette 37 containing a plurality of transfer materials 19, a paper feed roller 38, a feed roller 39,
It mainly includes a retard roller 40 for preventing double feed, a paper feed guide 41, a transport roller 43, and a registration roller 42.

During image formation, the paper feed roller 38 is driven and rotated in accordance with the image forming operation, and the transfer material 1 in the cassette 37 is rotated.
9 are separated and fed one by one, guided by a guide plate 41, and reach a registration roller 42 via a transport roller 43.

During the image forming operation, the registration rollers 42
Non-rotational operation of making the transfer material 19 stand still and the transfer material 1
The rotation of the transfer material 9 toward the intermediate transfer body 33 is performed in a predetermined sequence, and the position of the image and the transfer material 19 at the time of the transfer process, which is the next process, is aligned.

[Transfer Section] The transfer section is composed of a swingable transfer roller 34. The transfer roller 34 has a metal shaft wound with a medium-resistance foam elastic material, and is movable up and down in the figure and has driving. .

While the developer images of four colors are being formed on the intermediate transfer member 33, that is, while the intermediate transfer member 33 is rotating a plurality of times, the transfer roller 34 is connected by a solid line in the drawing so as not to disturb the image. And is separated from the intermediate transfer member 33.

After the formation of the four color toner images on the intermediate transfer member 33, the transfer roller 34 is shown by a thin line in the figure by a cam member (not shown) in accordance with the timing of transferring the color image onto the transfer material 2. At the upper position, it is pressed against the intermediate transfer body 33 via the transfer material 19 with a predetermined pressure. At this time, a bias is simultaneously applied to the transfer roller 34, and the toner image on the intermediate transfer body 33 is transferred to the transfer material 19.

Here, since the intermediate transfer member 33 and the transfer roller 34 are driven respectively, the transfer material 19 sandwiched between the two is subjected to the transfer process and at the same time, at a predetermined speed to the left in the figure. And is sent to the fixing unit 44 which performs the next process.

[Fixing Section] The fixing section 44 includes the developing devices 29 and 3
0 fixes the toner image formed on the transfer material 19 via the intermediate transfer body 33 to the toner image formed by the fixing roller 45. As shown in FIG. And a pressure roller 46 for pressing the transfer material 19 against the fixing roller 45. Each roller 4
Reference numerals 5 and 46 denote hollow rollers, each of which has a heater 4 inside.
7 and 48, and is configured to be driven to rotate and to convey the transfer material 19 at the same time.

That is, the transfer material 19 holding the toner image is conveyed by the fixing roller 45 and the pressure roller 46, and the toner is fixed to the transfer material 19 by applying heat and pressure.

Next, the configuration of the Y, M, and C rotary developing units, which are characteristic parts of the present invention, will be described with the yellow developing unit 29Y shown in FIGS. 2 and 3 as a representative example.

The developing device 29Y includes a developing container in which a container frame 29a for storing yellow toner and a developing frame 29b for rotatably supporting the developing roller 29YS and the like are welded.

The container frame 29a is provided with a stirring member 29YT in the toner storage chamber 29a1, and has an opening 29c at the joint with the developing frame 29b.

On the other hand, the developing frame 29b has a toner receiving chamber 29b1 and a toner supply chamber 29 adjacent to the opening 29c.
b2, a developing roller 29YS for supplying toner to the photosensitive drum 21 is rotatably mounted in the illustrated α direction, and a developing blade 29YB for regulating a layer thickness of the toner supplied to the developing roller 29YS is a blade. The developing roller 29YS is provided with an end peripheral surface sealing member 159 for preventing toner leakage at a longitudinal end of the developing roller 29YS. Further, a toner application roller 29YA that supplies the toner supplied from the toner storage chamber 29a1 to the developing roller 29YS is supported by the developing frame 29b so as to be rotatable in the α direction in the drawing.

The hatched portion in FIG. 3 indicates a nip portion between the developing blade 29YB and the developing roller 29YS.

At the time of image formation, the toner agitated and supplied from the toner storage chamber 29a1 by the rotation of the agitating member 29YT in the β direction is supplied to the developing roller 29YS by rotating the toner applying roller 29YA, and the toner layer is formed by the developing blade 29YB. The toner development is performed by forming a toner layer on the rotating developing roller 29YS while regulating the thickness, and transferring the toner according to the latent image formed on the photosensitive drum 21.

As shown in FIG. 3, the toner application roller 29
YA is rotatably supported by the developing frame 29b, but a clearance 100 is secured at both longitudinal ends of the toner applying roller 29YA, whereby the toner applying roller 29YA rubs against the developing frame 29b. You can rotate without.

Therefore, it is possible to prevent generation of coarse-grained toner at both ends in the longitudinal direction of the toner application roller 29YA, to create a flow in the toner accumulated in the toner receiving chamber 29b1, and to move the toner from the clearance 100 to the toner storing chamber 29YA.
The surplus toner is sent back to a1, and the occurrence of toner leakage can be prevented.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the toner application roller 2
9YA is rotatably supported by a bearing member 64 provided on the developing frame 29b, and at least one of the bearing members 6
4, the shaft body 29YA1 of the toner application roller 29YA is abutted and positioned, and a clearance 100 is secured at both ends in the longitudinal direction of the toner application roller 29YA with a set value in the range of 0.5 to 2.0 mm.

FIG. 4 shows a case where the shaft 29YA1 of the toner application roller 29YA abuts and is positioned on the bearing member 64 on the left side in the figure, and FIG. 5 shows the case where toner is applied to the bearing member 64 on the right side in the figure. Shaft 29YA of roller 29YA
1 shows a case in which the position of the end 1 is positioned.

The set value of the clearance 100 is determined by study, and is set to an optimum value for forming a flow in the toner accumulated in the toner receiving chamber 29c in order to prevent toner leakage.

The toner application roller 29YA is rotatable without rubbing against the developing frame 29b, thereby preventing generation of coarse toner.

Embodiment 3 As a third embodiment, the present invention is applied to a developing cartridge which has at least the developing devices of the above-described first and second embodiments and is detachable from an image forming apparatus. Similar effects can be obtained.

Embodiment 4 The fourth embodiment is applied to an image forming apparatus provided with the developing devices of the first and second embodiments, and the same effects as in the above embodiment can be obtained.

[0067]

As is apparent from the above description, according to the developing device, the developing cartridge and the image forming apparatus of the present invention, the clearance is secured between the end surface of the developer supply member and the developing container. Thus, even when a toner having a high particle size and a low viscosity is used, generation of coarse-grained toner in the vicinity of the support portion of the developer supply member is prevented, and the toner is transferred to the developer regulating member due to disturbance of a developed image or movement of coarse-grained toner. Can be prevented from leaking due to toner fusion, and toner leakage due to packing occurring due to excessive toner supply can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an image forming apparatus using a developing device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a developing device according to a first embodiment of the present invention.

FIG. 3 is an explanatory view of the developing device according to the first embodiment of the present invention when viewed from the photosensitive drum direction, when a developing roller is removed.

FIG. 4 is an explanatory view of the developing device according to the second embodiment of the present invention in which the developing roller is removed and the application roller is positioned to abut on the left side in the figure when viewed from the same direction as in FIG. 3;

FIG. 5 is an explanatory diagram of the developing device of the second embodiment according to the present invention when the developing roller is removed and the application roller abuts on the right side in the figure and is positioned when viewed from the same direction as in FIG. 3;

FIG. 6 is a cross-sectional view illustrating an example of a conventional developing device.

FIG. 8 is a view of the developing device of FIG.

[Explanation of symbols]

 21 Photosensitive Drum (Image Carrier) 29a Container Frame 29b Developing Frame 29Y, 29M, 29C Developing Device 29YA Toner Coating Roller (Developer Supplying Member) 29YA1 Shaft 29YB Developing Blade (Developer Regulating Member) 29YS Developing Roller (Developing) Agent carrier)

[Procedure amendment]

[Submission date] November 6, 1998 (1998.11.
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an image forming apparatus using a developing device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a developing device according to a first embodiment of the present invention.

FIG. 3 is an explanatory view of the developing device according to the first embodiment of the present invention when viewed from the photosensitive drum direction, when a developing roller is removed.

FIG. 4 is an explanatory view of the developing device according to the second embodiment of the present invention in which the developing roller is removed and the application roller is positioned to abut on the left side in the figure when viewed from the same direction as in FIG. 3;

FIG. 5 is an explanatory diagram of the developing device of the second embodiment according to the present invention when the developing roller is removed and the application roller abuts on the right side in the figure and is positioned when viewed from the same direction as in FIG. 3;

FIG. 6 is a cross-sectional view illustrating an example of a conventional developing device.

FIG. 7 is a view of the developing device of FIG. 6 viewed from a direction of an arrow A with a developing roller removed.

[Description of Signs] 21 Photosensitive drum (image carrier) 29a Container frame 29b Developing frame 29Y, 29M, 29C Developing device 29YA Toner coating roller (developer supply member) 29YA1 Shaft 29YB Developing blade (developer regulating member) 29YS developing roller (developer carrier)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Naofumi Horikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H077 AA31 AB03 AB14 AC04 AC05 AD06 AD13 AD17 AD23 AD35 AE03 BA08 BA09 BA10 CA02 CA12 EA14 FA22 GA13

Claims (9)

[Claims] A developing container for storing the developer, a developer carrier rotatably supported by an opening of the developing container and carrying the developer, and rotatably supported by the developing container;
A developing device having a developer supply member for supplying a developer to the developer carrier, wherein a clearance is secured between an end surface of the developer supply member and the developing container. . 2. The clearance is 0.5 to 2.0 mm.
The developing device according to claim 1, wherein 3. The developing device according to claim 1, wherein said developer supply member is secured in position by a shaft of said developer supply member abutting against at least one bearing member. 4. A developer container containing a developer, a developer carrier rotatably supported by an opening of the developer container and carrying the developer, and rotatably supported by the developer container.
A developing cartridge including at least a developing device having a developer supplying member for supplying a developer to the developer carrying member, the developing cartridge being detachably attached to an image forming apparatus main body, wherein an end face of the developer supplying member and the developing container A clearance is secured between the developing cartridge and the developing cartridge. 5. The clearance is 0.5 to 2.0 mm.
The developing cartridge according to claim 4, wherein 6. The developing cartridge according to claim 4, wherein said developer supply member secures said clearance by positioning a shaft of said developer supply member against at least one bearing member. 7. A developer container for storing a developer, a developer carrier rotatably supported by an opening of the developer container and carrying the developer, and rotatably supported by the developer container.
In an image forming apparatus including a developing device having a developer supply member that supplies a developer to the developer carrier, a clearance is secured between an end surface of the developer supply member and the developing container. An image forming apparatus comprising: 8. The clearance is 0.5 to 2.0 mm.
The image forming apparatus according to claim 7, wherein 9. The image forming apparatus according to claim 7, wherein the clearance is secured by positioning the shaft of the developer supply member against at least one of the bearing members.