JP2000029312A - Developing device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently recycle recovered toner recovered with a cleaning device and to prevent a deterioration in the quality of a formed toner image. SOLUTION: This developing device 32 for an image forming device is provided with a casing having groove parts isolated by a partition wall 88 whose both ends have notched parts 89 and 90, spirals 81 and 82 arranged in the groove parts, a toner supplying port 96 for supplying toner from a toner cartridge 91 onto the spiral 81 and a recovered toner supplying port 97 for supplying the toner recovered from the cleaning device.

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 image forming apparatus, and more particularly, to a cleaning device for collecting toner remaining on the peripheral surface of a photosensitive drum and a conveying device for conveying the toner collected by the cleaning device. The present invention relates to a developing device used for an image forming apparatus provided.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, and a facsimile apparatus, a document is placed on a document table provided on an upper surface of the apparatus, and the document image is irradiated with light and reflected from the document. The document image is read based on the. Based on the read document image, an electrostatic latent image is formed on the surface of the photosensitive drum. The photoreceptor drum is charged to a predetermined polarity by the main charging device, and when light is irradiated based on a document image, the charge at that portion is removed to form an electrostatic latent image.

Around the photosensitive drum, a developing device, a transfer device, a separating device, a cleaning device and the like are arranged. The developing device contains therein toner charged to the same polarity as the photosensitive drum. The toner stored in the developing device is adsorbed to a portion of the photosensitive drum where there is no charge at a position close to the developing device and the photosensitive drum. Therefore, the electrostatic latent image formed on the peripheral surface of the photosensitive drum is visualized as a toner image.

The transfer device applies a voltage having a polarity opposite to that of the toner from the back surface of the paper to the paper conveyed between the photosensitive drum and attracts the toner on the peripheral surface of the photosensitive drum onto the paper. To transfer the toner image. A separation device is disposed downstream of the transfer device in the sheet conveyance direction. This separation device prevents the paper from wrapping around the photoconductor drum.
The sheet is sucked from the back side, and for example, a separation needle to which a predetermined voltage is applied is employed.

The cleaning device is for removing the toner remaining on the peripheral surface of the photosensitive drum, and includes a cleaning blade that comes into contact with the peripheral surface of the photosensitive drum and scrapes off the toner. A fur brush for weakening the binding force, a toner transport device for transporting the toner separated from the peripheral surface of the photosensitive drum to a collection unit, and the like are provided. It is conceivable that the collected toner removed from the peripheral surface of the photosensitive drum is transported to the toner collecting case, for example, by attaching a toner collecting case in the image forming apparatus. It is also conceivable to directly convey the collected toner to a developing device, a toner cartridge, or the like for recycling.
In any case, a rotating body having spiral blades called a spiral is provided in a tube-shaped transport container, and by rotating the spiral, the toner is transported from the cleaning device to the recovery unit to be recovered. ing.

[0006]

The toner collected by the cleaning device is agitated in the developing device, rubbed between the developing roller and the photosensitive drum, rubbed between the photosensitive drum and the transfer roller, and removed from the cleaning device. It is considered that the quality has deteriorated to some extent since the toner has been compressed in the toner conveying device when it is carried out. When such collected toner is directly returned to the developing device for recycling, if the collected toner is supplied to the developing roller in an uneven manner, the image quality of the toner image formed on the photosensitive drum may be deteriorated.

Therefore, it is preferable that the new toner supplied from the toner cartridge and the like and the collected toner collected by the cleaning device are sufficiently stirred and supplied to the developing roller. SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device of an image forming apparatus that efficiently recycles collected toner collected by a cleaning device and prevents deterioration in image quality of a formed toner image.

[0008]

A developing device of an image forming apparatus according to the present invention includes a cleaning device for collecting toner remaining on the peripheral surface of a photosensitive drum, and a conveying device for conveying the toner collected by the cleaning device. Is a developing device used in an image forming apparatus including a developing material storage section, a first supply port, a second supply port, a stirring member, and a developing roller. The developing material storage section stores the developing material. The first supply port supplies toner from the toner cartridge to the developer storage section. The second supply port carries the toner collected by the cleaning device and transported by the transport device into the developer storage unit. The stirring member is for stirring the developer and the toner in the developer storage unit. The developing roller visualizes the electrostatic latent image formed on the peripheral surface of the photosensitive drum into a toner image.

Here, the stirring member can be configured to stir while transporting the developer and the toner in a predetermined direction. In addition, a first supply port is provided so that the stirring member replenishes the toner on a transport path for transporting the developer and the toner, and a second supply port is provided upstream of the first supply port in the transport direction of the stirring member. Can be.

Further, the stirring member can be a spiral rotatably arranged in the developer accommodating portion, and two agitators arranged in parallel with the rotation axis of the developing roller. A partition can be formed to isolate the transport path of each spiral except for both ends.
Further, a configuration may be adopted in which a stirring paddle for supplying the developing material and the toner stirred by the stirring member to the developing roller is rotatably disposed between the stirring member and the developing roller.

[0011]

FIG. 1 is a longitudinal sectional view of a copying machine to which an embodiment of the present invention is applied. The copying machine 1 has a main body 10 and a document holder 11 mounted on the upper part of the main body 10 so as to be openable and closable. An original platen 15 on which an original is placed is disposed on the main body 10 at an upper portion thereof. Inside the main body 10, an image forming unit 16 is provided at the left end as viewed from the front and substantially at the center in the vertical direction.
Further, a paper supply unit 17 for supplying paper to the image forming unit 16 is provided at a lower portion.

The paper supply unit 17 is detachably attached to the main body 10 and stores paper supply cassettes 18 and 19 for storing paper.
And a stack bypass 20 provided thereabove. An optical system 21 for reading image information of a document placed on the document table 15 is provided below the document table 15. The optical system 21 includes a light source 22 for irradiating light to the surface of the document placed on the document table 15 and mirrors 23, 24, and 2 for deflecting light reflected from the surface of the document.
5 and a lens 2 for converging the light from the mirror 25
6 and an image sensor 27 such as a CCD sensor that receives light converged by the lens 26 and generates an image data signal corresponding to an original image.

The image forming section 16 has a photosensitive drum 30 on the surface of which an electrostatic latent image is formed.
0, a main charging device 31, a developing device 32,
It has a transfer roller 33 and a cleaning device 34. The main charging device 31 is a device for charging the surface of the photoconductor drum 30, and is disposed diagonally above and to the right of the photoconductor drum 30. The photosensitive drum 3 is disposed diagonally below and to the right of the photosensitive drum 30 with a predetermined gap from the main charging device 31.
A developing device 32 for forming a toner image on the image sensor 0 is disposed. The developing device 32 stores toner inside, and visualizes the electrostatic latent image formed on the photosensitive drum 30 by the toner. The transfer roller 33 is a device for transferring the toner image on the photosensitive drum 30 to a sheet, and is disposed on the left side of the photosensitive drum 30. The cleaning device 34 is a device for removing residual toner and the like on the surface of the photoconductor drum 30.
0.

On the right side of the photosensitive drum 30, a laser unit 35 for forming an electrostatic latent image on the peripheral surface of the photosensitive drum 30 is provided. The laser unit 35 forms an electrostatic latent image on the peripheral surface of the photosensitive drum 30 based on an image data signal obtained from the image sensor 27. The paper feed unit 17 includes a vertical transport path 41 for transporting paper from each of the paper cassettes 18 and 19 toward the image forming unit 16 and a bypass transport path for transporting paper from the stack bypass 20 to the image forming unit 16. 42 are provided. Each paper cassette 1
Pickup rollers 43, 4 for taking out the stored paper are provided in the stack bypasses 8, 19 and the stack bypass 20.
4, 45 and a pair of paper feed rollers 46, 47, 48 for feeding the paper one by one to the transport path. The vertical transport path 41 is provided with pairs of transport rollers 49 and 50, and the bypass transport path 42 is provided with a pair of transport rollers 51. The vertical transport path 41 and the bypass transport path 42 join below the transfer position where the photosensitive drum 30 and the transfer roller 33 face each other. At the confluence, a registration roller 52 for stopping the conveyed sheet at a predetermined position is provided.

Above the photosensitive drum 30 and the transfer roller 33, a fixing device 53 for fusing and fixing the toner transferred onto the paper is provided. The fixing device 53
A heating roller 54 having a built-in heater and a pressure roller 55 pressing the heating roller 54 are provided. The sheet is nipped between the rollers and transported, and the toner image formed on the surface of the sheet is heated and fixed. Things.

Further above the fixing device 53, a branch portion 5 is provided.
6 are provided. On the right side of the branch portion 56, a discharge tray 57 for discharging sheets via a discharge roller pair 60 is provided.
And a discharge roller pair 6 disposed above the discharge tray 57.
1 and a sub-eject tray 58 from which sheets are ejected. A switchback unit 59 for reversing the sheet at the time of double-sided copying is provided at the lower left of the branch unit 56.
Is arranged. The branching portion 56 is provided with a branching claw 62 for switching the sheet conveying direction between the direction of the discharge tray 57 and the direction of the switchback portion 59. Branch claw 62
Two branch claws 63 and 64 are provided on the left side of. Below the two branch claws 63 and 64, a switchback transport path 65 for guiding a sheet to a switchback section 59 is provided.
A sub-tray conveyance path 66 for guiding the sheet to the sub-discharge tray 58 is provided above, and a sheet is conveyed to a finisher (not shown) such as a sorter or a staple sorter between the two branch claws 63 and 64. A finisher transport path 67 is provided. Branch claws 63, 64
Switches the transported paper to the switchback transport path 65,
It is possible to switch so as to guide to either the sub-tray conveyance path 66 or the finisher conveyance path 67. [Toner Conveying Mechanism] The cleaning device 34 is for removing toner remaining on the peripheral surface of the photosensitive drum 30. The toner removed from the peripheral surface of the photosensitive drum 30 is transferred to the toner conveying device via the toner conveying device. The developer is conveyed to the developing device 32. This toner conveying device will be described with reference to FIG.

The cleaning device 34 includes a cleaning blade (not shown) that presses against the peripheral surface of the photosensitive drum 30 in order to scrape off the toner remaining on the peripheral surface of the photosensitive drum 30, and a cleaning blade that scrapes off the toner. Spiral 70 that conveys the discharged toner to one end in the width direction
And The toner conveying device 71 is provided at one end in the width direction of the cleaning device 34. The toner conveying device 71 includes a toner conveying container 72 having a hollow inner tube shape, and a conveying member 73 rotatably disposed in the toner conveying container 72.

The toner conveying container 72 has an opening 74 communicating with one end in the width direction of the cleaning device 34 and a developing device 3.
2 is provided with a discharge port 75 for discharging toner. The transport member 73 includes a rotating shaft 76 and a contact member 77 provided in a spiral shape around the rotating shaft 76. The contact member 77 is made of a fiber made of a synthetic resin material,
6 and is provided so as to be in contact with the inner wall of the toner transport container 72.

The rotating shaft 76 is supported by bearings 78 and 79 provided at both ends in the length direction of the toner carrying container 72, and is driven to rotate by driving means (not shown).
The residual toner scraped off from the peripheral surface of the photosensitive drum 30 by the cleaning blade is conveyed by the spiral 70 to the toner conveying device 71 side, and falls onto the conveying member 73 in the toner conveying container 72 from the opening 74.

Here, the conveying member 73 is driven to rotate, and the toner conveyed by the spiral 70 is conveyed in the toner conveying container 72 in the right direction in FIG. The toner is further discharged into the developing device 32. At this time, the contact member 77 of the transport member 73 is formed of a brush made of an elastic synthetic resin material, and transports the toner while rubbing the inner wall of the toner transport container 72. Therefore, the tip of the contact member 77 always cleans the inner wall of the toner transport container 72, and the toner does not stick to the inner wall of the toner transport container 72. Further, since the contact member 77 has elasticity, the contact member 77 is always elastically deformed by rotating.
It is difficult for the toner to adhere to the surface, and even if the toner adheres, the toner is easily separated by elastic deformation, so that the adhered toner does not become a large lump and does not block the inside of the toner transport container 72. Therefore, the toner conveying device 71
Can be prevented from lowering. [Developing Apparatus] The developing apparatus 32 has a casing 85 as shown in FIGS. In this casing 85, two spirals 81 and 82 and a stirring paddle 83
And a developing roller 84 are provided.

The casing 85 includes spirals 81 and 8
Grooves 86 and 87 in which 2 are arranged are formed. The grooves 86 and 87 form a transport path in which the carrier and the toner are stirred and transported by the spirals 81 and 82. In the groove 86, the spiral 81 is driven to rotate, so that the carrier and the toner are transported upward from the bottom in FIG. Further, in the groove 87, the carrier 82 and the toner are transported downward from above in FIG. 3 by rotating the spiral 82. Between the groove 86 and the groove 87, a partition wall 88 for isolating both transport paths is formed. This partition wall 88
Has notches 89 and 90 at both ends in the length direction, and the notches 89 and 90 connect the groove 86 and the groove 87. From this, spiral 8
The carrier and toner conveyed by 1, 82
Circulation is performed along the groove 86 and the groove 87 while being stirred.

The developing device 32 has a detachable toner cartridge 91 for storing toner therein and replenishing the developing device 32 with toner. The toner cartridge 91 has a casing 94 in which a spiral 92 and a stirring paddle 93 are built. Casing 94
Is provided with a toner outlet 95 for discharging toner.

In the casing 85 of the developing device 32, a toner supply port 96 is provided at a position corresponding to the toner discharge port 95 of the toner cartridge 91. The toner supply port 96 is provided above the groove 86 in which the spiral 81 is arranged. In the casing 85 of the developing device 32, a collected toner supply port 97 is provided at a position corresponding to the discharge port 75 of the toner conveying device 71. The recovered toner supply port 97 is provided above the groove 87 in which the spiral 82 is disposed and near the notch 90.

As a result, the collected toner conveyed by the toner conveying device 71 is supplied to the collected toner supply port 9.
7, falls on the spiral 82. The position where the collected toner falls is the lower end position of the spiral 82 in FIG. Since the conveying direction of the spiral 82 is downward from above in FIG. 3, the collected toner dropped on the spiral 82 is immediately conveyed to the groove 86 in which the spiral 81 is arranged via the cutout 90. .

The collected toner is mixed with the toner supplied from the toner cartridge 91 through the toner supply port 96, is stirred with the carrier by the spiral 81, and is conveyed upward from the bottom in FIG. Spiral 8
The carrier and toner transported upward by 1 are
The spiral 8 is conveyed to the groove 87 through the cutout 89.
2 and is further conveyed in the groove 87.

A part of the carrier and toner transported in the groove 87 overflows to the stirring paddle 83 side, and the stirring paddle 83
Is transported to the developing roller 84 side. Developing roller 8
Due to the toner attached to 4, the electrostatic latent image formed on the peripheral surface of the photosensitive drum 30 is visualized as a toner image. As described above, since the collected toner collected by the cleaning device 34 is directly conveyed to the developing device 32 and recycled, the resources can be effectively used. In the developing device 32, two spirals 8 are provided.
1 and 82 are disposed, and by dropping the collected toner collected from the cleaning device 34 onto the spiral, the mixing of the carrier and the toner can be suitably performed. In particular, since the collected toner supply port 97 is provided upstream of the supply port 96 for supplying new toner from the toner cartridge 91 in the carrier and toner transport paths formed by the spirals 81 and 82, each of the spirals 81 , 82, the carrier, the recovered toner and the new toner can be sufficiently stirred, and the image quality does not deteriorate.

[0027]

According to the present invention, new toner from the toner cartridge is supplied from the first supply port, and recovered toner recovered by the cleaning device is supplied from the second supply port. The collected toner can be sufficiently stirred by the stirring member. Therefore, even if the recovered toner that is expected to be slightly deteriorated is used, it is sufficiently stirred with the new toner.
It is possible to reduce a decrease in image quality.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a copying machine employing an embodiment of the present invention.

FIG. 2 is an explanatory view of a main part.

FIG. 3 is an explanatory diagram of a main part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier 30 Photosensitive drum 32 Developing device 34 Cleaning device 71 Toner transport device 72 Toner transport container 81, 82 Spiral 86, 87 Groove portion 88 Partition wall 91 Toner cartridge 96 Toner supply port 97 Recovered toner supply port

Claims (6)

[Claims] 1. A developing device for use in an image forming apparatus, comprising: a cleaning device for collecting toner remaining on the peripheral surface of a photosensitive drum; and a transport device for transporting the toner collected by the cleaning device. A developer container for storing materials, a first supply port for replenishing toner from the toner cartridge to the developer container, and a toner collected by the cleaning device and transported by the transport device to the developer material. A second supply port for carrying the toner into the storage unit, a stirring member for stirring the developer and the toner in the developer storage unit, and a toner image formed on the peripheral surface of the photosensitive drum. And a developing roller for visualizing the image. 2. The developing device of an image forming apparatus, wherein the stirring member stirs the developer and the toner while transporting the developer and the toner in a predetermined direction. 3. The first supply port is provided so that the stirring member replenishes toner on a transport path for transporting the developer and the toner, and the second supply port is provided more than the first supply port. It is provided on the upstream side in the transport direction of the stirring member,
A developing device for the image forming apparatus according to claim 2. 4. The developing device for an image forming apparatus according to claim 1, wherein said stirring member is a spiral rotatably disposed in said developer accommodating portion. 5. The stirring member comprises two spirals arranged in parallel with a rotation axis of the developing roller, and a partition separating a conveying path of each spiral except for both ends between the two spirals. The developing device of the image forming apparatus according to claim 4, wherein the developing device is formed. 6. A stirring paddle for supplying the developing material and toner stirred by the stirring member to the developing roller is rotatably disposed between the stirring member and the developing roller. 6. The developing device of the image forming apparatus according to any one of 1 to 5.