JP3210210B2 - 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 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, an image forming apparatus has a process in which an image carrier and any process means such as a charger, a developing device, and a cleaning device are integrated into a common housing functioning as a support. Make up the cartridge,
Some process cartridges are detachable from the main body of the image forming apparatus to improve the maintainability and serviceability of the image forming apparatus.

[0003] Development will be described using the process cartridge as an example.

A developing device is provided for visualizing an electrostatic latent image formed on a photosensitive drum as an image carrier with a developer (toner). A developing roller is provided in the developing device, and the toner in the developing device is carried by the action of the magnetic force of the developing roller and supplied to the photosensitive drum.

FIG. 6 is an enlarged sectional view of a developing roller as a background on which the present invention is found.

As shown in FIG. 6, the developing roller comprises a cylindrical developing sleeve 1 rotating in a certain direction and a magnet roller 2 disposed in the developing sleeve 1. The developing sleeve 1 has flange members 4a and 4b fixed at both ends by press-fitting or bonding.
The flange members 4a and 4b are pivotally supported by the developing device main body 3 via bearing members 5a and 5b. In addition, bias power is supplied to the developing roller so that the sleeve electrode 6 fixed to the flange member 4b is fixed to be in contact with the inner diameter of the developing sleeve 1 and is in contact with the electrode plate 7 fixed to the holder 9b.

When the process cartridge is mounted in the main body of the image forming apparatus, the electrode plate 7 and the contact 11 on the main body side of the image forming apparatus come into contact with each other, as shown in FIG.

The magnet roller 2 disposed in the developing sleeve 1 holds a magnetic pole on the circumference of the magnet roller 2 at a predetermined angle with respect to a photosensitive drum (not shown) so that a predetermined amount of toner is provided. Is supplied to the photosensitive drum. Therefore, at least one end 2b of the end of the magnet roller 2 has a shape that allows a predetermined angle to be determined. In FIG. 6, the cross-sectional shape of one end 2a is a round shape, and the cross-sectional shape of the other end 2b is a D-shaped protrusion. Both ends 2a and 2b of the magnet roller 2 are supported by holders 9a and 9b fixed to the developing device main body 3, and a predetermined angle of the magnet roller 2 is set by a D formed on the holder 9b.
The predetermined angular position is maintained by the engagement between the shape hole and the D-shaped convex portion at one end 2b of the magnet roller 2. At the time of assembling, when fixing the holder 9b to the developing device main body 3 with screws or the like, the positioning holes 9 of the holder 9b are used.
The magnet roller 2 is assembled so as to engage with the D-shaped convex portion of the end 2b of the magnet roller 2 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 mounted, it is necessary to provide positional accuracy to both the positioning hole 9d for the main body of the developing device and the end face 2b of the magnet roller away from the 9d. Very poor assemblability to do.

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

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a developer-carrying developer-carrying member, and a non-cylindrical rotation-prohibiting portion provided at the end of the developer-carrying member. And an electrode member that supplies power to the developer carrier and fits into the rotation prohibiting portion to stop rotation of the magnet roll.

[0013]

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

In the process cartridge of the present embodiment, a rotatable photosensitive member 20 as an image carrier, a charger 30, a developing device 40, and a cleaner 50 are provided in a cartridge frame.
And four kinds of process means are integrally accommodated.

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

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

FIG. 1 is an enlarged sectional view of the vicinity of the developing sleeve of the present embodiment.

In FIG. 1, a cylindrical developing sleeve which rotates in a fixed direction is provided, and a 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 non-magnetic cylindrical developing sleeve 1 by press-fitting or bonding together with a sleeve electrode 6, and is developed via a sliding bearing member 5b which 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 by the developing main body 3 via a bearing member 5a. At both ends of the developing sleeve 1, rollers 8 which are in contact with a photosensitive drum (not shown) and maintain a constant distance between the photosensitive drum and the developing sleeve 1 are inserted. A gear 10 is engaged with the flange 4a, and is driven by a gear fixed to a photosensitive drum (not shown) by press-fitting or bonding, so that the developing sleeve 1 rotates in a predetermined direction at a predetermined rotation speed. 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 the electrode plate 7 is mounted on the main body of the image forming apparatus, the electrode plate 7 comes into contact with the contact 11 in the main body of the image forming apparatus and the sleeve electrode, thereby establishing electrical conduction with the developing sleeve, and supplying a developing bias voltage to the developing roller. It becomes possible.

In this case, the magnet roller 2 disposed in the development souv 1 must maintain a magnetic pole on the circumference of the magnet roller 2 at a predetermined angular position with respect to a photosensitive drum (not shown). In this embodiment, the one end shape 2b of the magnet roller 2 is a non-cylindrical convex rotation prohibition portion having a D-shaped cross section. In order to hold the magnet roller 2 at a predetermined angular position, the bearing member 5b is provided with a rotation stop shape that fits with the rotation prohibiting portion of the magnet roller end 2b, and has a D-shaped hole shape (5c).

With this configuration, as shown in FIG. 2, the magnetic pole of the magnet roller 2 can be adjusted to a predetermined angle position in the state of the developing sleeve unit.
In this state, only by engaging the 5d portion of the bearing member 5b with the two portions 3a of the developing device main body, the predetermined angular position of the magnet roller 2 with respect to the unillustrated photosensitive drum can be easily maintained. Next, the holders 9a and 9b are
If the developing device main body 3 is pivotally supported by a screw or the like without the need for the positioning work described above, the developing device main body 3 is completed, and the efficiency of the work is greatly improved.

At this time, since the sliding bearing 5b rotatably supports the flange 4 at the end of the developing sleeve,
It is sufficient to provide a D-shaped hole at the center, and the precision of the parts does not increase.

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

In this embodiment, the rotation of the magnet roller is stopped by an 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 angular position, a D-shaped hole (FIG. 3) is fitted into the rotation prohibiting portion 2b at the end of the magnet roller.
(B)) is provided on the electrode plate 7.

In this embodiment as well, the angle of the magnet roller is already determined when it is configured as a sleeve unit, and this sleeve unit may be simply assembled to the developing device, so that the efficiency of the assembling operation can be improved as in the above-described embodiment.

Further, since the electrode plate only needs to provide sufficient contact for power supply and does not require high positional accuracy, the number of components does not increase even if a rotation stop 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 stopping rotation can be easily obtained by making it coincide with the center of the bearing member.

(Third Embodiment) As shown in FIG.
In order to hold the magnet roller 2 at a predetermined angular position, the bearing member 5b has a shape that engages with the magnet roller end 2b, and the developing member 5b is made conductive to apply a developing bias 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 configuration can be simplified.

(Fourth Embodiment) As shown in FIG. 5, in order to hold the magnet roller at a predetermined angular 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 conductive, and supply a developing bias to the developing sleeve via the bearing member and the flange member.

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

[0034]

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

[Brief description of the 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 sectional view of a developing device according to a second embodiment of the present invention.

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

FIG. 5 is a partially enlarged 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 as a background of the present invention.

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

[Explanation of symbols]

 DESCRIPTION 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

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isamu Saito 3-7-22 Sakae, Niiza-shi, Saitama (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/08-15/09

Claims (3)

(57) [Claims] 1. A developer-carrying member for supporting and rotating a developer, a magnet roll provided in the developer-carrying member and having a non-cylindrical rotation prohibiting portion at an end, and supplying power to the developer-carrying member. And an electrode member fitted to the rotation prohibiting portion to stop rotation of the magnet roll. 2. The developing device according to claim 1, further comprising a bearing that rotatably supports the developer carrier, wherein the electrode member is fixed to the bearing. 3. The developing device according to claim 1, wherein the electrode member is a conductive sliding bearing that rotatably supports the developer carrier.