JPH0922189A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of assembling work by providing an electrode member which feeds power to a developer carrier and is fitted to a rotation inhibiting part, so as to stop the rotation of a magnet roller. SOLUTION: When an electrode plate 7 is attached to an image forming device body, the electrode plate 7 comes into contact with a contact 11 and a sleeve electrode in the image forming device body, to be electrically conductive with a developing sleeve and apply a developing bias voltage to a developing roller. Then, the shape of one end 2b of the magnet roller 2 is for a projected noncylindrical rotation inhibiting part having a D-shaped cross section. Further, for holding the magnet roller 2 at a fixed angle position, a bearing member 5b has a rotation stopping shape for fitting to the rotation inhibiting part of the end part 2b of the magnet roller, that is, a D-shaped hole shape. Then, in a developing sleeve unit state, the magnetic pole of the magnet roller 2 is placed at the fixed angle position. In this state, only a part 5d of the bearing member 5b is engaged at two positions 3a of a developing unit body, the magnet roller 2 can be easily kept at the fixed angle position with respect to a photoreceptor drum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an image forming apparatus such as a copying machine or a printer and develops an electrostatic image on an image carrier.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus, an image carrier and any of process means such as a charger, a developing device, and a cleaning device are integrally incorporated into a common housing functioning as a support to carry out a process. Make up the cartridge,
Some process cartridges are attachable to and detachable from the image forming apparatus main body to improve the maintainability and serviceability of the image forming apparatus.

Development will be described by taking the process cartridge as an example.

A developing device is provided to visualize the electrostatic latent image formed on the photosensitive drum, which is an image carrier, with a developer (toner). A developing roller is provided in the developing device, and the magnetic force of the developing roller causes the toner in the developing device to be carried and supplied to the photosensitive drum.

FIG. 6 shows an enlarged sectional view of the developing roller which is the background of the present invention.

As shown in FIG. 6, the developing roller is composed of a cylindrical developing sleeve 1 which rotates in a fixed direction and a magnet roller 2 which is disposed in the developing sleeve 1. Further, the developing sleeve 1 has flange members 4a and 4b fixed to both ends thereof by press fitting or adhesion,
The flange members 4a and 4b are pivotally supported on the developing device main body 3 via bearing members 5a and 5b. Further, for bias power supply to the developing roller, the sleeve electrode 6 fixed to the flange member 4b is fixed so as to come into contact with the inner diameter of the developing sleeve 1, and comes into contact with the electrode plate 7 fixed to the holder 9b.

When this process cartridge is attached to the main body of the image forming apparatus, the electrode plate 7 and the contact 11 on the main body of the image forming apparatus are in contact with each other as shown in FIG.

The magnet roller 2 disposed in the developing sleeve 1 holds a predetermined amount of toner by holding the magnetic poles on the circumference of the magnet roller 2 at a predetermined angle with respect to the photosensitive drum (not shown). Is being supplied to the photosensitive drum. Therefore, at least one end 2b of the end portion of the magnet roller 2 has a shape capable of determining a predetermined angle. In FIG. 6, the cross-sectional shape of one end 2a is round and the cross-sectional shape of the other end 2b is D-shaped convex. Both ends 2a, 2b of the magnet roller 2 are supported by holders 9a, 9b fixed to the developing device main body 3, and a predetermined angle of the magnet roller 2 is provided on the holder 9b.
By engaging the shaped hole and the D-shaped convex portion of the one end 2b of the magnet roller 2, the predetermined angular position is maintained. At the time of assembly, when fixing the holder 9b to the developing device main body 3 with screws or the like, the positioning hole 9 of the holder 9b
The magnet roller 2 is assembled so as to be engaged with the D-shaped convex portion of the end portion 2b while adjusting d.

[0009]

When the magnetic poles on the circumference of the magnet roller are arranged at a predetermined angle with respect to the photosensitive drum,
Before the magnet roller is positioned by the holder, it is rotatable in the developing sleeve.

For this reason, when the holder is attached, it is necessary to provide positional accuracy on both the positioning hole 9d for the developing device main body and the end surface 2b of the magnet roller which is separated from the positioning hole 9d. Very bad to assemble.

Further, the holder cannot be assembled unless the positioning hole 9d and the fitting hole of the D-shaped convex portion are high in accuracy, and the accuracy of parts required for the holder is high.

[0012]

According to the present invention for solving the above-mentioned problems,
A developer carrying body that carries and rotates a developer, a magnet roll provided in the developer carrying body and having a non-cylindrical rotation inhibiting portion at an end, a power supply to the developer carrying body, and a rotation inhibiting portion. A developing device, comprising: an electrode member that is fitted to prevent rotation of the magnet roll; a developer carrier that carries a developer and rotates; and an end portion provided in the developer carrier. A magnet roll having a non-cylindrical rotation inhibiting portion, and a slide bearing that rotatably supports the developer carrier and that fits in the rotation inhibiting portion to prevent rotation of the magnet roll. It is a developing device.

[0013]

FIG. 7 is a sectional view of a process cartridge having a developing device embodying the present invention.

The process cartridge according to the present embodiment has a rotatable photosensitive member 20 as an image carrier, a charging device 30, a developing device 40, and a cleaner 50 in a cartridge frame.
And the four process means are integrally housed.

The developing device 40 contains a one-component magnetic toner T.

Reference numeral 1 designates a developing sleeve which is a developer carrying member which carries the toner T and rotates, 43 a regulating blade which regulates the toner layer thickness on the developing sleeve 1, 44 a scooping sheet,
Reference numeral 45 denotes an end seal that prevents toner from leaking from the end.

FIG. 1 is an enlarged sectional view around the developing sleeve of this embodiment.

In FIG. 1, the developing roller is a cylindrical developing sleeve that rotates in a fixed direction, and the magnet roller 2 is disposed in the developing sleeve 1.

The magnet roller 2 has a plurality of magnetic poles in the circumferential direction, and the magnetic pole arrangement is set in a predetermined positional relationship.

A flange 4b is fixed to one end of the developing sleeve 1 of a non-magnetic cylindrical body together with a sleeve electrode 6 by press fitting or adhesion, and development is performed via a slide bearing member 5b that rotatably supports the developing sleeve 1. It is pivotally supported by the container body 3. A flange 4a is fixed to the other end of the developing sleeve by press fitting or bonding, and is pivotally supported on the developing main body 3 via a bearing member 5a. Rollers 8 that contact a photosensitive drum (not shown) and keep the distance between the photosensitive drum and the developing sleeve 1 constant are inserted at both ends of the developing sleeve 1. A gear 10 is engaged with the flange 4a, and the developing sleeve 1 is rotated in a fixed direction at a predetermined rotation speed by being driven by a gear fixed to a photosensitive drum (not shown) by press fitting or adhesion. The sleeve electrode 6 fixed to the flange member 4b is
It is fixed so as to be inscribed in the developing sleeve 1, and is in contact with the electrode plate 7 fixed to the bearing member 5b. When this electrode plate 7 is attached to the image forming apparatus main body, it contacts the contact 11 inside the image forming apparatus main body and the sleeve electrode, and is electrically connected to the developing sleeve, and supplies a developing bias voltage to the developing roller. It becomes possible.

The magnet roller 2 arranged in the developing souve 1 here is required to hold the magnetic poles on the circumference of the magnet roller 2 with respect to the photosensitive drum (not shown) at a predetermined angular position. In the present embodiment, the one end shape 2b of the magnet roller 2 is a non-cylindrical section having a D-shaped convex rotation prohibition section. In order to hold the magnet roller 2 at a predetermined angle position, the bearing member 5b is provided with a rotation stopping shape that fits with the rotation prohibiting portion of the magnet roller end portion 2b to form a D-shaped hole shape (5c).

With this structure, as shown in FIG. 2, the magnetic pole of the magnet roller 2 can be aligned with a predetermined angular position in the state of the developing sleeve unit.
In this state, the magnet roller 2 can be easily maintained at a predetermined angular position with respect to the photosensitive drum (not shown) simply by engaging the two 3a of the developing device main body with the 5d portion of the bearing member 5b. Next, attach the holders 9a and 9b to the magnet roller 2
By pivotally supporting the developing device main body 3 with a screw or the like without requiring the positioning work, the developing device main body 3 will be completed, and a large work efficiency can be achieved.

At this time, since the slide bearing 5b rotatably supports the flange 4 at the end portion of the developing sleeve,
It suffices if a D-shaped hole is provided at the center of the hole, and the precision of the parts does not increase.

(Second Embodiment) FIG. 3 shows a partially enlarged view of another developing device embodying the present invention.

In this example, the rotation of the magnet roller is stopped by the electrode plate for supplying power to the developing sleeve.

That is, as shown in FIG. 3, in order to hold the magnet roller 2 at a predetermined angle position, a D-shaped hole (FIG.
(B)) is provided on the electrode plate 7.

In this example as well, when the sleeve unit is constructed, the angle of the magnet roller is already determined, and since it is sufficient to assemble this sleeve unit to the developing device, the efficiency of the assembling work can be achieved as in the above example.

Further, since it is sufficient for the electrode plate to obtain sufficient contact for power supply and high positional accuracy is not required, the number of parts does not increase even if a rotation stopping function is added to this electrode plate.

Further, since this electrode plate is fixed to the bearing member 5b, the position of the D-shaped hole for the rotation stopper can be easily obtained by aligning it with the center of the bearing member.

(Third Embodiment) As shown in FIG.
In order to hold the magnet roller 2 at a predetermined angle position, the bearing member 5b has a shape that engages with the magnet roller end 2b, and the bearing member 5b is made conductive so that a developing bias is applied to the developing sleeve via the bearing member. Power is being supplied.

In this example, since the electrode plate 7 can be omitted, the number of parts can be reduced and the structure can be simplified.

(Fourth Embodiment) As shown in FIG. 5, in order to hold the magnet roller at a predetermined angle position, the bearing member 5b has a shape that engages with the magnet roller end 2b. Further, the bearing member 5b and the flange member 4b are electrically conductive, and the developing bias is supplied to the developing sleeve through the bearing member and the flange member.

In this example, since the sleeve electrode 6 and the electrode plate 7 are not used, the number of parts can be reduced and the structure can be simplified.

[0034]

As described above, according to the present invention, the assembling work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a developing device embodying the present invention.

FIG. 2 is a sectional view of a developing sleeve unit.

FIG. 3 is a partially enlarged cross-sectional view of a developing device according to a second embodiment of the present invention.

FIG. 4 is a partially enlarged cross-sectional view of a developing device according to a third embodiment of the invention.

FIG. 5 is a partially enlarged cross-sectional view of a developing device according to a fourth embodiment of the present invention.

FIG. 6 is a partially enlarged cross-sectional view of a developing device that is the background of the present invention.

FIG. 7 is a sectional view of a process cartridge embodying the present invention.

[Explanation of symbols]

 1 developing sleeve 2 magnet roller 3 developing device main body 4 flange 5 bearing member 6 sleeve electrode 7 electrode plate 8 roller 9 holder 10 gear 11 bias contact of image forming apparatus main body

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Isamu Saito 3-7-22 Sakae, Niiza City, Saitama Prefecture

Claims (4)

[Claims] 1. A developer carrying member carrying and rotating a developer, a magnet roll provided in the developer carrying member and having a non-cylindrical rotation inhibiting portion at an end thereof, and supplying power to the developer carrying member. A developing device further comprising: an electrode member that fits in the rotation prohibiting portion and stops rotation of the magnet roll. 2. The developing device according to claim 1, further comprising a bearing that rotatably supports the developer carrier, and the electrode member is fixed to the bearing. 3. The developing device according to claim 1, wherein the electrode member is a conductive slide bearing that rotatably supports the developer carrier. 4. A developer carrying member which carries a developer and rotates, a magnet roll which is provided in the developer carrying member and has a non-cylindrical rotation inhibiting portion at an end thereof, and the developer carrying member is rotatable. And a slide bearing which is fitted to the rotation prohibiting portion and stops the rotation of the magnet roll.