JP4545913B2 - Sleeve unit mounting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus and a process cartridge that can be attached to and detached from the main body.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image process, a photosensitive drum and process means acting on the photosensitive drum are integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. The method is adopted.
[0003]
According to this process cartridge system, the apparatus can be maintained by the user himself / herself without depending on the service person, so that the operability can be remarkably improved. As shown in FIGS. 7 and 8, as a method of attaching the developing sleeve 102 to the developing container 101 of the cartridge which is a replacement part, the covers 103 and 104 are fitted to both ends in the longitudinal direction of the developing container 101, and development is performed with the covers 103 and 104. A method of supporting the sleeve 102 is common.
[0004]
[Problems to be solved by the invention]
However, the conventional image forming apparatus has a problem that there are many parts for supporting the developing sleeve 102 and the positioning accuracy of the developing sleeve 102 with respect to the developing container 101 is low.
[0005]
Therefore, the present invention aims to facilitate assembly and improve the support accuracy of the developing sleeve by reducing the number of parts for supporting the sleeve.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a sleeve unit mounting method according to the present invention is a sleeve unit for developing an electrostatic latent image formed on a photosensitive drum, the developing sleeve being a hollow nonmagnetic metal cylinder, A fixed magnet inside the developing sleeve, a driving-side swing arm provided on the driving side for positioning the developing sleeve on the developing container, and a non-driving for positioning the developing sleeve on the developing container In the sleeve unit attaching method for attaching the non-driving side swing arm provided on the side and the sleeve unit having the developing unit to the developing container,
(A) The sleeve unit is moved between two developing container walls provided at both ends in the longitudinal direction of the developing container at intervals longer than the length of the sleeve unit, and is provided in the developing container. The drive-side swing arm and the non-drive-side swing arm are engaged with a mounting groove, a support hole provided in the developer container wall, a shaft of the magnet, and an end seal provided in the developer container Is temporarily positioned by contacting the developing sleeve so that is substantially coaxial,
(B) After the temporary positioning, the developing sleeve is slid to the driving side in the longitudinal direction, and one shaft of the magnet is fitted into one of the support holes,
(C) inserting a support member from the other outside of the support hole, and a hole provided in the support member;
Fitting the other shaft of the magnet;
It is characterized by that.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
[First embodiment]
A first embodiment of a sleeve unit mounting method according to the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of an image forming apparatus, FIG. 2 is a longitudinal sectional view of a process cartridge, FIG. 3 is a longitudinal sectional view showing a support structure of a developing sleeve, and FIG. 4 is a perspective view of a developing container as viewed from below. 5 is a cross-sectional view showing the developing sleeve being attached, and FIG. 6 is a cross-sectional view after the developing sleeve is assembled.
[0008]
In the following description, the longitudinal direction refers to a direction that intersects the recording medium conveyance direction and is parallel to the recording medium. Further, left and right are left and right as viewed in the conveyance direction of the recording medium. Further, the top of the process cartridge means the top of the process cartridge in the mounted state.
[0009]
As shown in FIG. 1, a feeding cassette 3 for loading and storing a plurality of recording media (for example, recording paper, OHP sheets, cloth, etc.) P is detachably mounted on the image forming apparatus 1. The recording medium P fed from the feeding cassette 3 by the pickup roller 4 is separated one by one by the retard roller pair 5 and conveyed to the registration roller pair 8 by the conveying rollers 6 and 7 which are conveying means.
[0010]
The recording medium P conveyed to the registration roller pair 8 has its skew corrected by being abutted against the nip of the registration roller pair 8 that has stopped rotating, and is sent to the secondary transfer roller pair 39 at a predetermined timing. .
[0011]
On the other hand, in the image forming apparatus 1, four process cartridges BY, BM, BC, and BB of yellow, magenta, cyan, and black are detachably arranged in parallel to the main body of the image forming apparatus. The process cartridges BY, BM, BC, and BB integrally form a photosensitive drum 15 (15Y, 15M, 15C, and 15BK) and process means that act on the photosensitive drum 15. Optical scanning systems 2Y, 2M, 2C, and 2BK are provided for the process cartridges BY, BM, BC, and BB, respectively, and a toner image is formed on the photosensitive drum 15 for each color by an image signal. Each color toner is superimposed and transferred onto the intermediate transfer belt 12 rotated by the transfer rollers 11Y, 11M, 11C, and 11BK.
[0012]
The recording medium P sent to the secondary transfer roller pair 39 is transferred with the toner image on the intermediate transfer belt 12, fixed with the fixing device 13, and then discharged onto the apparatus main body 29 by the discharge roller pair 9, 10. Are discharged to the discharge tray 14.
[0013]
The image forming units 37Y, 37M, 37C, and 37BK include optical scanning systems 2Y, 2M, 2C, and 2BK, process cartridges BY, BM, BC, and BB, and toner containers TY, TM, TC, and TB. Since the configuration of each process cartridge is the same, the process cartridge BY will be described, and the description of the other process cartridges will be omitted.
[0014]
As shown in FIG. 2, the process cartridge BY has a charger 16 as a charging means, an exposure unit, a sleeve unit 21 as a developing means, a developing container 22, and a transfer opening around a photosensitive drum 15. is there. In this embodiment, a two-component developer having magnetic carrier powder (hereinafter referred to as toner) is used.
[0015]
The magnetic brush charger 16 uses a magnetic carrier, and a fixed magnet 18 is provided in a hollow cylindrical charging roller 17 that is rotatably supported. After the transfer, the charger 16 rotates in a direction to take in the toner remaining on the photosensitive drum 15, and cleans the photosensitive drum 15.
[0016]
As shown in FIG. 4, the sleeve unit 21 includes a developing sleeve 24 that is a developer carrier sleeve, and driving side spacers 19 that are provided at both ends of the developing sleeve 24 and regulate the gap between the sleeve surface and the photosensitive drum 15. And a non-drive side spacer 20, a swing arm (drive side swing arm, non-drive side swing arm) 38 for positioning the developing sleeve 24 to the developing container 22, and a sleeve gear 36. The swing arm 38 is provided outside the drive side spacer 19 and the non-drive side spacer 20, and the sleeve gear 36 is inserted and disposed outside the swing arm 38 on the drive side spacer 19 side.
[0017]
The developing sleeve 24 is a hollow cylindrical non-magnetic metal cylinder, and is rotatably supported. A fixed developing magnet 23 is included in the developing sleeve 24. The developing sleeve 24 rotates in the same direction as the photosensitive drum 15, and the circumferential surface moves in a direction opposite to the moving direction of the circumferential surface of the photosensitive drum 15. The photosensitive drum 15 and the developing sleeve 24 are non-contact with a gap of about 0.2 to 1.0 mm, and development (two-component non-contact development) can be performed while the toner is in contact with the photosensitive drum 15. Is set to Since the image forming apparatus 1 has a printing capacity of 20 to 30 sheets / minute, the rotation speed of the drum 15 is set to about 75 rpm, and the rotation speed of the developing sleeve is set to about 230 rpm.
[0018]
The toner mixed with the carrier is supplied by stirring screws 27 and 28 in a casing partitioned by a partition wall 26 in the longitudinal direction excluding both ends. The stirring screws 27 and 28 are both rotated at about 330 rpm in order to supply toner to the developing sleeve 24 that rotates at a high speed, and the toner is stirred and conveyed. The toner supplied from the toner container TY falls to one end side of the agitating screw 27 and is sent in one direction in the longitudinal direction while being agitated by the stirring screw 27, and a portion without the partition wall 26 on the other end side (not shown) And sent to one end of the stirring screw 28. The toner sent to one end side of the stirring screw 28 is fed in one direction in the longitudinal direction while being stirred by the stirring screw 28, and passes through the portion without the partition wall 26 (not shown) on the other end side of the stirring screw 27. Sent to the other end.
[0019]
Here, a part of the toner stirred and conveyed by the stirring screw 28 is pumped up by the pole of the developing magnet 23 as the developing sleeve 24 rotates, and is supplied to the developing sleeve 24. In this supply process, the toner is regulated by a regulating blade (developing blade) 25 disposed perpendicular to the developing sleeve 24, and a thin layer is formed on the developing sleeve 24. Here, when the toner formed in a thin layer is conveyed to the developing main electrode, a spike is formed by the magnetic force. The electrostatic latent image on the photosensitive drum 15 is developed with the toner formed in the shape of a spike, and then the toner on the developing sleeve 24 is returned into the developing container 22 by a repulsive magnetic field.
[0020]
A DC voltage and an AC voltage are applied to the developing sleeve 24 from a power source (not shown). In general, in the two-component development method, when an AC voltage is applied, the development efficiency increases and the image becomes high-quality, but conversely, fogging easily occurs. For this reason, by providing a potential difference between the DC voltage applied to the developing sleeve 24 and the surface potential of the photosensitive drum 15, toner is prevented from adhering to the non-image area during development, and fogging is prevented.
[0021]
Next, a method for attaching the developing sleeve will be described. As shown in FIG. 4, the developing container 22 is provided with an abutting-side developing container wall 30 and a developing container wall 31 at both ends on the drive transmission side and the non-driving side in the longitudinal direction. The distance between the abutting side developing container wall 30 and the developing container wall 31 is longer than the entire length of the sleeve unit 21. The sleeve unit 21 is moved so as not to hit the two developer container walls, and temporarily attached so that the swing arm 38 engages with the swing arm mounting groove 34 of the developer container 22. The developing sleeve 24 is in pressure contact with the developing end seal 35 affixed to the developing container 22, and the axial center of the sleeve unit 21 and the magnet shaft support hole 30a of the abutting side developing container wall 30 are temporarily positioned substantially coaxially.
[0022]
As shown in FIG. 5, the sleeve unit 21 is inserted into the developing container 22 as described above to make a temporary determination state. In FIG. 5, the sleeve gear 36 is indicated by broken lines so that the state of the developing sleeve 24 and the magnet shaft 33 can be easily understood. In the tentatively determined state, the drive side spacer 19 serves as a movement allowance for allowing the developing sleeve 24 to move between a step between the swinging arm 38 positioned in the swinging arm mounting groove 34 and the developing sleeve 24 (hereinafter referred to as a sleeve step). It is arranged so that there is a gap. On the other hand, the non-driving side spacer 20 is substantially in close contact with both the sleeve step and the swing arm 38.
[0023]
Next, slide movement will be described. As shown in FIG. 6, when the developing sleeve 24 is slid and moved to the longitudinal drive side with respect to the developing container 22 and the swing arm 38, the magnet shaft 33 and the magnet shaft support hole 30a of the developing container 22 are substantially coaxial. Therefore, the magnet shaft 33 is easily fitted into the magnet shaft support hole 30a of the abutting side developing container wall 30. When the developing sleeve 24 is slid, the driving side spacer 19 comes into close contact with the swing arm 38 at the sleeve step, and the non-drive side spacer 20 generates a gap between the swing arm 38 and the sleeve step. Since the non-driving side spacer 20 is movable in the longitudinal direction, a sleeve cover (protective cover) for protecting the developing sleeve 24 is attached after the sleeve unit 21 is attached, and the non-driving side spacer is provided by a rib provided on the sleeve cover. Position 20.
[0024]
Next, insertion of the magnet support member 32 will be described. FIG. 5 shows a state before insertion, and FIG. 6 shows a state after insertion. As shown in FIG. 5, a magnet support member 32 for supporting the magnet shaft 33 is inserted into the magnet support member mounting hole 31 a of the developer container 22 from the outside of the developer container wall 31. The inserted magnet support member 32 is fitted into the magnet support member mounting hole 31 a so that the developing container 22 and the magnet shaft 33 are coaxially arranged, and is fitted into the magnet shaft 33.
[0025]
In this way, the abutting side developing container wall 30 and the developing container wall 31 are integrally formed with the developing container 22, and the magnet shaft 33 is supported by the magnet shaft support hole 30a of the developing container 22 on the driving side and the non-driving side on the non-driving side. The magnet support member 32 is supported by the magnet support member mounting hole 31a of the developing container 22 through the magnet support member 32. As a result, the number of parts to be supported is reduced and assembly is facilitated, and the positioning accuracy of the magnet shaft 33 with respect to the developing container 22 is significantly improved.
[0026]
Next, a developer carrier sleeve replacement method will be described. First, the magnet support member 32 is removed from the magnet shaft 33, the developing sleeve 24 is slid in the longitudinal direction, the developing magnet 23 is removed from one of the magnet supporting member mounting holes 31a, and the sleeve unit 21 is removed from the developing container 22. Thereafter, the developing sleeve 24 is replaced by attaching a new developing sleeve 24 by the above-described developing carrier sleeve attaching method.
[0027]
【The invention's effect】
As described above, the entire length of the sleeve unit is made shorter than the width of the developing container, slides after temporarily attaching to the container, the developing magnet is inserted into one of the mounting holes and fitted, and the magnet support member is attached in front. The other side of the hole is inserted from the outside of the mounting hole, and the hole of the magnet support member and the magnet shaft are fitted to attach the developing carrier sleeve. Thereby, the assembly can be facilitated by reducing the number of parts to be supported, and the positioning accuracy of the developing magnet roller with respect to the developing container can be remarkably improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an image forming apparatus. FIG. 2 is a longitudinal sectional view of a process cartridge.
FIG. 3 is a longitudinal sectional view showing a support structure of a developing sleeve.
FIG. 4 is a perspective view of the developing container as viewed from below.
FIG. 5 is a cross-sectional view showing the developing sleeve during installation.
FIG. 6 is a cross-sectional view of the developing sleeve after assembly.
FIG. 7 is a developing container in the middle of assembling a conventional developing sleeve.
FIG. 8 is a developing container after assembling a conventional developing sleeve.
[Explanation of symbols]
BB ... Process cartridge BC ... Process cartridge BM ... Process cartridge BY ... Process cartridge P ... Recording medium TB ... Toner container TC ... Toner container TM ... Toner container TY ... Toner container 1 ... Image forming apparatus 2BK ... Optical scanning system 2C ... Optical scanning System 2M ... Optical scanning system 2Y ... Optical scanning system 3 ... Feed cassette 4 ... Pickup roller 5 ... Retard roller pair 6 ... Conveying roller 7 ... Conveying roller 8 ... Registration roller pair 9 ... Discharge roller pair
10… discharge roller pair
11BK ... transfer roller
11C: Transfer roller
11M ... transfer roller
11Y: Transfer roller
12 ... Intermediate transfer belt
13… Fixer
14… discharge tray
15… Photoconductor drum
16… Magnetic brush charger
17… Charging roller
18… Magnet
19… Driver side spacer
20… Non-drive side spacer
21… Sleeve unit
22… Developer container
23… Developing magnet
24… Development sleeve
25… Regulator blade
26… Bulkhead
27… stirring screw
28… stirring screw
29… Main unit
30… Abutting developer wall
30a… Magnet shaft support hole
31… Developer container wall
31a… Magnet support member mounting hole
32… Magnet support member
33… Magnet shaft
34… Swing arm mounting groove
35… Development end seal
36… Sleeve gear
37BK ... Image forming section
37C ... Image forming section
37M ... Image forming section
37Y ... Image forming section
38… Swing arm
39… Secondary transfer roller pair

Claims (2)

A sleeve unit for developing an electrostatic latent image formed on a photosensitive drum, the developing sleeve being a hollow non-magnetic metal cylinder, a magnet fixed inside the developing sleeve, and the developing sleeve as a developing container A drive-side swing arm provided on the drive side for positioning the sleeve, and a non-drive-side swing arm provided on the non-drive side for positioning the developing sleeve on the developing container. In the sleeve unit attaching method for attaching to the developer container,
(A) The sleeve unit is moved between two developing container walls provided at both ends in the longitudinal direction of the developing container at intervals longer than the length of the sleeve unit, and is provided in the developing container. The drive-side swing arm and the non-drive-side swing arm are engaged with a mounting groove, a support hole provided in the developer container wall, a shaft of the magnet, and an end seal provided in the developer container Is temporarily positioned by contacting the developing sleeve so that is substantially coaxial,
(B) After the temporary positioning, the developing sleeve is slid to the driving side in the longitudinal direction, and one shaft of the magnet is fitted into one of the support holes,
(C) A support member is inserted from the other outer side of the support hole, and the hole provided in the support member is fitted to the other shaft of the magnet.
A sleeve unit mounting method characterized by the above. The sleeve unit includes a driving spacer that regulates a gap between the developing sleeve and the photosensitive drum between the developing sleeve and the driving-side swing arm, the developing sleeve, and the non-driving-side swing arm. A non-driving side spacer that regulates a gap between the developing sleeve and the photosensitive drum,
In the temporary positioning state, the non-driving side spacer contacts the developing sleeve and the non-driving side swing arm,
In a state where the developing sleeve is slid to the driving side in the longitudinal direction, the driving side spacer is in contact with the developing sleeve and the driving side swing arm,
Creating a gap between the non-driving side spacer and the non-driving side swing arm;
After that, by attaching a protective cover for protecting the developing sleeve to the developing container, a rib provided on the protective cover is inserted into the gap to position the developing sleeve in the longitudinal direction. Item 2. The sleeve unit mounting method according to Item 1.

Images