JP3410941B2 - 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,
In particular, the present invention relates to a developing device arranged adjacent to a photosensitive drum of an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer and a facsimile, an electrostatic latent image based on image data is formed on the surface of a photosensitive drum by a laser scanning unit, for example. A developing device, a transfer separation device, a cleaning device, and the like are provided adjacent to each other around the photosensitive drum. The electrostatic latent image formed on the surface of the photoconductor drum is visualized as a toner image by the developing roller provided in the developing device. The toner image on the surface of the photoconductor drum is transferred to the surface of the paper by the transfer separation device.

In such an image forming apparatus, magnetic 2
When developing using a component type developer, a parallel developing roller which is driven to rotate in the opposite direction to the photosensitive drum and a reverse developing roller which is driven to rotate in the same direction as the photosensitive drum are provided side by side. A developing device may be used. In this case, it is possible to efficiently collect the carrier in the developing device after supplying the developer to the surface of the photosensitive drum to adhere the toner to the surface of the photosensitive drum.

In the developing device proposed in Japanese Utility Model Laid-Open No. 3-54956, the parallel developing roller and the reverse developing roller are axially supported by the same supporting side plate and detachably attached to the housing of the developing device. Has been. When mounting the supporting side plate to which the two developing rollers are attached to the housing of the developing device, first, the parallel developing roller is positioned with respect to the housing of the developing device, and then the rotation axis of the parallel developing roller is centered. Attach it so that it can rotate.
After this, rotate the rotating shaft of the parallel developing roller as the center,
The opposite developing roller is positioned and the supporting side plate is fixed to the housing.

[0005]

In the developing device described above, the blade for restricting the height of the magnetic brush formed by the developer formed on the surface of the parallel developing roller to a substantially predetermined value is the housing. It is provided inside and close to the parallel developing roller. This blade is provided on the inner side of the housing with respect to the position where the parallel developing roller and the opposite developing roller face each other, and the tip position is arranged a predetermined distance apart from the surface of the parallel developing roller.

The distance between the tip position of the blade and the surface of the parallel developing roller determines the height of the magnetic brush formed on the surface of the parallel developing roller, that is, the so-called spike-cutting dimension. The position of the blade and the parallel developing roller is adjusted while confirming the adjustment. As described above, when the parallel developing roller and the reverse developing roller are provided side by side on one supporting side plate, first, only the parallel developing roller is attached to the supporting side plate when adjusting the spike cutting dimension. Install the support side plate to the housing in the closed state.
In this state, the position of the blade is adjusted to adjust the cutting size. After that, the supporting side plate is once removed from the housing, the reverse developing roller is attached to the supporting side plate, and the supporting side plate is attached to the housing again.

In such a developing device, the work for adjusting the cutting size is very complicated, and it is difficult to maintain high accuracy of the cutting size. An object of the present invention is to provide a developing device including a parallel developing roller and a reverse developing roller, which facilitates the work of adjusting the cutting edge size and can position each part accurately and easily. It is in.

[0008]

A developing device according to the present invention is a developing device arranged adjacent to a photosensitive drum of an image forming apparatus, and includes a housing, a parallel developing roller, and
The counter developing roller, the support plate, and the regulation plate are provided.
The housing is provided with the developer therein and is disposed adjacent to the photosensitive drum. The parallel developing roller is axially supported by the housing so that its surface is separated from the surface of the photosensitive drum by a predetermined distance, and is driven to rotate in the direction opposite to the photosensitive drum.
The opposite developing roller is provided together with the parallel developing roller so that its surface is separated from the surface of the photosensitive drum by a predetermined distance, and is driven to rotate in the same direction as the photosensitive drum. The support plate detachably supports the reverse developing roller and is rotatable with respect to the housing about the rotation axis of the parallel developing roller. The regulation plate is provided inside the housing and adjacent to the parallel developing roller, and regulates the height of the magnetic brush formed on the surface of the parallel developing roller.

Here, it is possible to adopt a structure in which the support plate is biased in the direction in which the opposite developing roller is pressed against the photosensitive drum. Further, the rotation shafts of the parallel developing roller and the reverse developing roller may be provided with a gap holding roller member having an outer diameter slightly larger than that of each developing roller.

In the developing device according to the present invention, the reverse developing roller is attachable to and detachable from the support plate, and the tip end position of the regulating plate and the surface of the parallel developing roller are adjusted in order to adjust the cutting edge size. When adjusting the distance between and, it is possible to easily perform the work by removing only the reverse developing roller. Further, the support plate is rotatable about the rotation axis of the parallel developing roller, and after the parallel developing roller is once positioned, even if the support plate is rotationally moved, the parallel developing roller with respect to the photosensitive drum is rotated. The position of is unchanged.

Further, when the support plate is biased in the direction in which the opposite developing roller is pressed against the photosensitive drum,
It is possible to easily position the reverse developing roller with respect to the photosensitive drum simply by attaching the reverse developing roller after adjusting the brush cutting dimension with the reverse developing roller removed. Further, if the gap holding roller members each having an outer diameter slightly larger than that of each developing roller are provided on the rotating shafts of the parallel developing roller and the reverse developing roller, the photosensitive drum of each developing roller is provided. It is possible to accurately and easily perform positioning with respect to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a copying machine to which an embodiment of the present invention is applied. In the figure, an original placing table 2 is fixed to the upper surface of a copying machine main body 1. A document holder 3 is mounted on the document table 2 so as to be openable and closable. On the other hand, paper feed cassettes 5 and 6 are detachably mounted on the right side of the copying machine main body 1 in the figure, and a paper discharge tray 7 for discharging copied paper is mounted on the left side. . An optical system 8 for reading a document is provided in the upper portion of the copying machine main body 1. This optical system 8
Is composed of a light source, a mirror, a lens, and the like. Further, a photoconductor drum 9 on the surface of which an electrostatic latent image is formed is arranged at substantially the center of the copying machine main body 1. Around the photosensitive drum 9, a main charger 10 for charging the photosensitive drum 9 to a predetermined electric charge, a developing device 11, a transfer corona discharger 12 for transferring a toner image onto a sheet, and a photosensitive drum 9 Separating corona discharger for separating paper 1
3, and a cleaning device 14 for removing the residual toner on the surface of the photosensitive drum 9.

Paper feed rollers 16a and 16b are provided above the leading ends of the paper feed cassettes 5 and 6, respectively. Roller 16
A sheet feeding device 17 that conveys a sheet to the image forming unit is provided on the downstream side of a and 16b in the sheet feeding direction. On the downstream side of the image forming unit, a carrying device 18 for carrying the paper on which the toner image on the photosensitive drum 9 is transferred is provided.
A fixing device 20 for fixing the transferred image on the conveyed sheet is provided between the conveying device 18 and the discharge roller 19.
Is provided.

The developing device 11 comprises a developing device body 21 and a toner hopper 35 connected to the developing device body 21. The toner hopper 35 stores toner for replenishing the developing device main body 21. As shown in FIG. 2, the developing device main body 21 has a housing 22 into which the developer is supplied, and is arranged adjacent to the photosensitive drum 9 rotating in the direction of arrow A. The developing device main body portion 21 includes a pair of counter developing roller 23 and parallel developing roller 24 that are provided side by side so as to face the photosensitive drum 9. The developing rollers 23 and 24 are arranged in the housing 22 so that the opposite developing roller 23 is on the upper side, and the rollers 23 and 24 are rotatable in opposite directions. Opposite direction Development roller 23 rotation direction (arrow B
Direction) is the same direction as the rotation direction of the photoconductor drum 9, and therefore the photoconductor drum 9 and the opposite developing roller 23
In the portion facing to and, the movement direction of the surface is opposite. The rotation direction of the parallel developing roller 24 (direction of arrow C) is
The rotation direction of the photoconductor drum 9 is opposite to that of the photoconductor drum 9. Therefore, the surface of the photoconductor drum 9 and the parallel developing roller 24 face each other in the same direction. A plurality of fixed magnets (not shown) are provided inside the reverse developing roller 23 and the parallel developing roller 24, respectively. Further, the reverse developing roller 23 and the parallel developing roller 2
Reference numerals 4 are arranged at a predetermined distance from each other so that the developer can move between both rollers by the magnetic force of the internal magnet.

Inside the housing 22, in order to stir the developer and to supply the developer to the parallel developing roller 24 side, it rotates in the same direction as the parallel developing roller 24 (arrow D direction). A driven stirring paddle 25 is provided. Further, inside the housing 22, a brush height regulating blade for regulating the layer thickness of the developer that can be held on the surface by the parallel developing roller 24 (the height of the magnetic brush formed by the developer formed on the surface). 26 is provided so that its tip position is separated from the surface of the parallel developing roller 24 by a predetermined distance. From this, the parallel developing roller 24 from the stirring section
Draws up the developer, regulates the magnetic brush to a predetermined height by the blade 26, and then distributes the developer by magnetic poles (different poles) provided at the opposing portions of the developing rollers 23 and 24.

As shown in FIG. 3, one end of the rotary shaft 27 of the parallel developing roller 24 is pivotally supported by the first support plate 29 via an adjusting bearing member 28. As shown in FIG. 5, the other end of the rotary shaft 27 is pivotally supported by the second support plate 30 to position the fixed magnetic pole. At both ends of the parallel developing roller 24 in the length direction, the parallel developing roller 2 is provided.
A DS roller 31 having an outer diameter slightly larger than the outer diameter of No. 4 is provided. The DS roller 31 maintains its peripheral surface in contact with the surface of the photosensitive drum 9 so that the surface of the parallel developing roller 24 and the surface of the photosensitive drum 9 are separated from each other by a predetermined distance.

A drive system (not shown) is provided on the second support plate 30.
Idle gears 32, 33 for transmitting the driving force from the
Is rotatably supported, and the gear 3 attached to the rotary shaft 27
4, the driving force from the driving system is transmitted to rotate the parallel developing roller 24. The reverse developing roller 2 is provided on the first support plate 29 and the second support plate 30.
A reverse developing roller mounting portion 36 for receiving the rotating shaft 37 of No. 3 is formed. The first support plate 29 and the second support plate 30 are rotatably attached to the housing 22 about the rotation shaft 27 of the parallel developing roller 24, and the springs 38 and 39 allow the reverse developing process. The roller mounting portion 36 is urged in a direction to press it toward the photosensitive drum 9.

The rotating shaft 37 of the reverse developing roller 23 has one end pivotally supported by the first bearing member 40 and the other end pivotally supported by the second bearing member 41. DS rollers 42 having an outer diameter slightly larger than the outer diameter of the opposite developing roller 23 are provided at both ends of the opposite developing roller 23 in the length direction. This D
The S roller 42 keeps the surface of the opposite developing roller 23 and the surface of the photosensitive drum 9 separated from each other by a predetermined distance by the contact of the peripheral surface thereof with the surface of the photosensitive drum 9.

The reverse developing roller 23 includes a first bearing member 40.
Also, in a state of being axially supported by the second bearing member 41, the reverse developing roller mounting portion 3 of the first support plate 29 and the second support plate 30.
6 can be attached, as shown in FIGS. 4 and 6,
It is fixed to the first support plate 29 and the second support plate 30 by screws 43, 44 and 45. At this time, the gear 4 attached to the other end side of the rotating shaft 37 of the opposite developing roller 23
6 is an idle gear 3 supported by the second support plate 30.
Mesh with 2. As a result, the driving force from the driving system is transmitted to the reverse developing roller 23.

In the developing device according to the present invention, the parallel developing roller 24 is attached to the first support plate 29 and the second support plate 30, and the housing 22 of the first support plate 29 and the second support plate 30 and the photosensitive drum 9 are attached. To position. After that, the reverse developing roller 23 axially supported by the first bearing member 40 and the second bearing member 41 is attached to the first support plate 29 and the second supporting member 29.
It is attached to the support plate 30. The first support plate 29 and the second support plate 30 are biased by springs 38 and 39, respectively, and the opposite developing roller 23 is pressed against the photosensitive drum 29 side. Therefore, the reverse developing roller 23
The surface of the DS roller 42 provided on the rotating shaft 37 of the contact roller comes into contact with the peripheral surface of the photosensitive drum 9, and the reverse developing roller 23 is located at a position where the surface is separated from the surface of the photosensitive drum 9 by a predetermined distance. Will be positioned in. At this time, since the first support plate 29 and the second support plate 30 rotate about the rotation shaft 27 of the parallel developing roller 24, the position of the parallel developing roller 24 with respect to the photosensitive drum 9 remains unchanged. The positioning accuracy of the parallel developing roller 24 is not impaired.

In the developing device of the present invention as described above, when the cutting edge size is adjusted by the blade 26, the reverse developing roller 23 is removed as shown in FIG. This is, for example, the screws 43, 44, 4 in FIGS. 4 and 6.
5, the first bearing member 40 and the second bearing member 4 are removed.
It is possible to easily remove 1 by separating it from the first support member 29 and the second support member 30. At this time, the first support plate 29 and the second support plate 30 are urged toward the photoconductor drum 9 side by the spring 38 and the spring 39, respectively. It is configured to not move.

In this state, the thickness gauge 50 is provided between the surface of the parallel developing roller 24 and the tip of the blade 26.
Is inserted, and the positions of the blade 26 and the parallel developing roller 24 are adjusted while checking the gap. When the edge-cutting dimension adjustment is completed, the reverse developing roller 23 is processed in the same manner as described above.
Attach. At this time, it is not necessary to reposition the reverse developing roller 23, the work is simple, and high positioning accuracy can be maintained.

[0023]

In the developing device according to the present invention, the reverse developing roller is attachable to and detachable from the support plate, and the tip end position of the regulating plate and the parallel developing roller are used to adjust the cutting edge size. When adjusting the distance from the surface of the sheet, it is possible to easily remove the reverse developing roller and perform the operation.
Further, the support plate is rotatable about the rotation axis of the parallel developing roller, and after the parallel developing roller is once positioned, even if the support plate is rotationally moved, the parallel developing roller with respect to the photosensitive drum is rotated. The position of does not change, and the positioning accuracy of the parallel developing roller is not impaired.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a copying machine in which an embodiment of the present invention is adopted.

FIG. 2 is an enlarged cross-sectional view of a main part thereof.

FIG. 3 is a side view of a main part thereof.

FIG. 4 is a side view of a main part thereof.

FIG. 5 is a side view of the main part and the like.

FIG. 6 is a side view of the main part and the like.

FIG. 7 is an explanatory diagram when adjusting the cutting size.

[Explanation of symbols]

11 Developing device 21 Development unit main body 22 housing 23 Reverse developing roller 24 Parallel developing roller 26 blades 27 rotation axis 29 First support plate 30 Second support plate 31 DS Coro 37 rotation axis 38 springs 39 spring 40 First bearing member 41 Second bearing member 42 DS Coro

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-142568 (JP, A) JP-A-5-88531 (JP, A) JP-A-6-75471 (JP, A) JP-A-7- 121027 (JP, A) Actual Kaihei 1-177756 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 504 G03G 15/08 501 G03G 15/09

Claims (3)

(57) [Claims] 1. A developing device arranged adjacent to a photosensitive drum of an image forming apparatus, wherein a housing is provided adjacent to the photosensitive drum and a surface of the housing is provided with a developer. A parallel developing roller that is axially supported by the housing so as to be separated from the surface of the photosensitive drum by a predetermined distance and is driven to rotate in a direction opposite to the photosensitive drum, and the surface thereof is separated from the surface of the photosensitive drum by a predetermined distance. As described above, the reverse developing roller is provided in parallel with the parallel developing roller and is rotationally driven in the same direction as the photosensitive drum, and the reverse developing roller is detachably supported and the parallel developing roller is rotated. first and second support plate about an axis which is rotatable with respect to the housing, an internal of the housing is provided in proximity to the併向developing roller, the併向developing roller Developing apparatus comprising a regulating plate for regulating the height of the magnetic brush formed on the surface, a. 2. The developing device according to claim 1, wherein the first and second support plates are biased in a direction in which the opposite developing roller is pressed against the photosensitive drum. 3. A roller member for holding a gap, the outer diameter of which is slightly larger than that of each developing roller, is provided on the rotation shafts of the parallel developing roller and the reverse developing roller, respectively. Developing device.