JP2584043B2 - Developing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a developing device used in an electrophotographic apparatus.

2. Description of the Related Art Conventionally, there is a developing unit that develops an electrostatic latent image on an image carrier by providing a developing roller in a toner container containing toner and supplying the toner in the toner container from the developing roller to the image carrier. . Conventionally, as described in JP-A-62-192771 and JP-A-63-144370, means for maintaining the relative position between the image carrier and the developing roller constant has been considered. The contents described in JP-A-62-192771 are such that a case of a developing unit is movably supported by rollers, and the developing unit is urged toward the image carrier by a spring and pressed downward by another spring. It is. Further, the contents described in JP-A-63-144370 are such that a developing casing holding a developing roller is rotatably supported by a support shaft, and the developing casing is urged toward an image carrier by a spring. It is.

The problem described in JP-A-62-192771 is that when the strength of the spring is weak, the position of the developing unit becomes unstable, and the gap between the developing roller and the image carrier fluctuates. It will be easier. For this reason, while increasing the strength of the spring,
The strength of the supporting portion for supporting the spring must be increased, and the total weight increases because the number of components increases.
Similarly, those described in JP-A-63-144370,
The force of the spring for urging the developing casing must be increased. In addition, the springs have large variations in force and therefore have a large influence, and require a space for disposing the spring and a supporting member for supporting the spring.

Means for Solving the Problems A lower body having a support portion for positioning and supporting the bearing of the image carrier and having an opening opening upward is provided, and a cover for opening and closing the opening is provided above the lower body. A developing unit is formed by rotatably attaching a developing roller to a toner container containing toner, and the developing unit is rotatably held with an axis parallel to the axis of the image carrier. A fulcrum, which is located on the image carrier side above the center of gravity of the developing unit and above the developing roller and makes the developing roller abut on the image carrier, is provided inside the lower main body, and the developing unit is provided on the cover. An opposing portion is provided in the unit with a predetermined gap therebetween.

Since the center of gravity of the developing unit is located on the side opposite to the image carrier with respect to the vertical line passing through the fulcrum, the developing unit can be urged toward the image carrier with the fulcrum as a center. By rotating the unit by its own weight, the developing roller can be brought into contact with the image carrier or the like to be stabilized at a fixed position.
Further, the floating of the developing unit due to extreme vibration during transportation or the like can be prevented by the opposing portion of the upper body, and the opposing portion for preventing the floating should face the developing unit with a predetermined gap. Accordingly, it is possible to prevent the vibration generated by applying an external force to the upper main body from being transmitted to the developing unit.

Embodiment An embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a longitudinal sectional side view showing the entire structure, in which 1 is a lower body constituting a part of the main body of the electrophotographic printer, and this lower body 1 connects a base cover 2 and an upper cover 3. One end of a top cover 4 as an upper body is attached to the upper part of the lower body 1 so as to be vertically rotatable. A power supply 5 and a circuit board 6 are mounted on the base cover 2. The upper cover 3 is provided with a paper transport path 8 for transporting the paper in the paper feed cassette 7. At the end of the paper transport path 8, a paper receiving tray 9 formed on the upper surface of the top cover 4 is provided. A paper discharge path 10 is connected to the connection section, and a switching section 11 that switches the paper discharge path to the side of the lower main body 1 on the extension surface of the paper discharge path 10 or the paper transport path 8 is connected to the connection section. Is provided. The paper transport path 8 includes a paper feed roller 12 that comes into contact with the uppermost paper of the paper cassette 7, a start sensor 13 that optically detects the paper being transported, A registration roller 14 whose rotational movement is controlled by a signal, and a transfer unit 15 that transfers a developed image on an image carrier 24 described below to a sheet
A separating unit 16 for separating the sheet from the image carrier 24, a high-voltage power supply 17, and a fixing unit 18 for holding the sheet passing through the transfer unit 15 and fixing a transfer image on the sheet are arranged from upstream to downstream. They are arranged sequentially.

The upper cover 3 is provided with a vertically open basket 19 located above the paper transport path 8, and the image forming unit 20 removably housed in the basket 19 is provided with an image carrier unit 21 and a developing unit. Consists of unit 22. The image carrier unit 21 is a charging unit that rotatably mounts image carriers 24 on both sides of a support 23 and applies electric charges to the image carriers 24.
25, a static eliminator 26 for exposing the image carrier 24 to make the charge on the outer periphery uniform, and a waste toner container 27 attached to the support 23, and the waste toner adhered to the image carrier 24 in the waste toner container 27. A blade 28 for scraping off the toner and a roller 29 for transporting the scraped waste toner toward the back of the waste toner container 27 are attached. The developing unit 22 is provided with a developing roller 31 and a stirring blade 32 for stirring the toner in a toner container 30 containing the toner (see FIG. 5). Further, at both ends of the developing roller 31, flange-like projections 31a that contact the outer peripheral surfaces of both ends of the image carrier 24 are formed. Further, an optical section 33 for scanning a light beam on the photosensitive surface of the image carrier 24 is mounted on the inner surface of the top cover 4.

Next, FIGS. 1, 3 and 4 show the mounting structure of the basket 19 and the image forming section 20. FIG. FIG. 1 is a longitudinal sectional side view showing a supporting structure of the basket 19 and the image forming unit 20, FIG. 3 is an exploded perspective view showing a relationship between the lower body 1 and the basket 19, and FIG. FIG. 2 is a plan view of a basket 19 which has been set. As shown in these figures, a pair of handles 34 located above both ends of the image carrier 24 are integrally formed at both ends of the basket 19.
The image carrier protrudes from both outer sides of the support 23.
Guide groove 36 that guides bearing 35 that supports 24 so that it can move up and down
And a guide groove 38 for guiding a support shaft 37 protruding from both sides of the toner container 30 so as to be vertically movable. Also,
The transfer unit 15 and the peeling unit 16 are connected to the upper cover 3
The supporting portion 40 for positioning and supporting the bearing 35 and the fulcrum portion 41 for positioning and supporting the supporting shaft 37 so as to be rotatable are fixed to the frame 39 fixed to the frame 39 by screws. Are formed, and a stopper 42 that abuts on the lower end of the support 23 of the image carrier unit 21 is provided upright. The support portion 40 and the fulcrum portion 41 have a concave shape with an upper opening, and have a shape that expands upward.

Further, the frame 39 is provided with locking means 43 which resiliently engages with the image carrier unit 21. The locking means 43 includes a lever 45 that rotates about a support shaft 44 and a support shaft 46.
And a lever 47 that rotates around the center. These levers
The upper portions 45 and 47 are urged in the opposite directions by the urging force of a spring 48. At the top of one lever 45, the bearing
A downward slope 49 for pressing the bottom 35 of the support portion 40 of the frame 39 and a slope 50 whose inclination is changed upward from the slope 49 are formed, and the other lever 47 is provided with the image carrier unit. A downward slope 52 for pressing a pin 51 protruding from the outer peripheral surface of the support 23 of the support 21 and a slope 53 whose inclination is changed upward from the slope 52 are formed. Further, a handle 54 is integrally formed on the housing of the charge removing section 26 which is a component of the image carrier unit 21, and handles 56 are integrally formed on both outer sides of the toner container 30. .
These handles 54 and 56 are so close to the handle 34 that the fingers of the same hand are hooked when the handle 34 of the basket 19 is gripped. In addition, these handles 54, 56 have upward pressing portions 55, 57 and downward finger hanging portions 55a, 5
7a are formed.

Further, a first surface is provided on the lower surface of the housing of the optical unit 33.
As shown in the drawing, a proximity portion 61 is formed on the upper edge of the support 23 of the image carrier unit 21 so as to face the gap with a predetermined gap.

Thus, the position of the fulcrum portion 41 is different from that of the developing unit.
The developing roller is located on the image carrier 24 side from the center of gravity of the developing roller 22.
It is located above 31. Further, a motor 58 for driving the developing roller 31 and the stirring blade 32 is fixed to the developing unit 22.
The power supply input terminal 59 connected to the power supply input terminal 59 is provided so as to protrude downward, and a knife-shaped connector 60 for elastically holding the power supply input terminal 59 is fixed to the inner surface of the frame 39. This connector 60 is connected to a power supply. Motor 58
Is positioned in a direction away from the image carrier 24 with respect to the fulcrum portion 41. Further, as shown in FIG. 5, an opposing portion 62 is formed on the inner surface of the top cover 4 so as to oppose a part of the toner container 30 with a predetermined gap s. The facing portion 62 is formed by a cushioning member.

FIG. 6 is a partial front view showing a state in which the support shaft 37 of the developing unit 22 is fitted to the fulcrum 41 of the frame 39 with the frame 39 as a cross section.

In such a configuration, during jam processing and maintenance, the top cover 4 is pivoted upward to open the upper surface of the upper cover 3, and in this state, the handle 34 is gripped and the basket 19 is moved to the image carrier unit 21. Developing unit 22
Then, the paper transport path 8 is opened. Alternatively, the image carrier unit 21 and the developing unit are placed in a state in which the basket 19 is positioned inside the upper cover 3 by placing a finger on the finger holders 55a, 57a of the handles 54, 56 and pulling up.
22 can be removed alone.

When assembling after jam processing or maintenance,
The bearing 35 of the image carrier unit 21 is inserted into the guide groove 36 of the basket 19 taken out of the upper cover 3, and the support shaft 37 of the developing unit 22 is inserted into the guide groove 38, and the handle 34 of the basket 19 is removed. The basket 19 is stored in the upper cover 3 while the bearing 35 is fitted to the support portion 40 of the frame 39 and the support shaft 37 is fitted to the fulcrum portion 41. Alternatively, a bearing 35 or a support shaft 37 is provided in the guide grooves 36, 38, the support portion 40, and the fulcrum portion 41 of the basket 19 stored in the upper cover 3.
The image carrier unit 21 and the developing unit 22
Are stored in the basket 19. At this time, the bearing 35 whose movement other than the vertical direction is restricted by the guide groove 36 is supported by the upward slope 50 of the lever 44, and the pin 51 is supported by the upward slope 53 of the lever 47. The pressing portion 55 of the handle 54 can be pressed by the finger playing while holding the grip. By this operation, the lever 45 rotates counterclockwise against the force of the spring 48 by the component force generated by the contact between the bearing 35 and the slope 50, and allows the bearing 35 to move downward. Similarly, the pin 51 is also supported by the inclined surface 53 of the lever 47, and by pressing down the pressing portion 55 of the handle 54,
The lever 47 pivots clockwise against the force of the spring 48 by the component force generated by the contact between the pin 53 and the slope 53, and allows the pin 51 to move downward. Then, the lever 45 returned by the return force of the spring 48 presses the bearing 35 against the bottom of the support portion 40 with its downward slope 49, and similarly, the lever 47 presses the pin 51 downward with its downward slope 52 to support The lower edges of both sides of the body 23 are pressed against the stopper 42.

The developing unit 22 is supported by the support shaft 37 positioned at the fulcrum portion 41 by its own weight.
Is located on the image carrier 24 side from the center of gravity of the developing unit 22 so that the developing unit 22
Rotating clockwise around the center 41, the projections 31 a provided at both ends of the developing roller 31 abut on the outer periphery of the end of the image carrier 24. As a result, the developing unit 22 is mounted on the frame 39 in a stable state in which the gap at the intermediate portion between the image carrier 24 and the developing roller 31 is kept constant.

As described above, the image carrier unit 21 and the developing unit 22
Means that the image carrier 24 can be accurately positioned relative to the transfer unit 15 and the peeling unit 16 because it is mounted in a stable state on the frame 39 that positions and fixes the transfer unit 15 and the peeling unit 16.

In addition, in the case of jam handling and maintenance,
In this process, the bearing 35 presses the downward slope 49 of the lever 45, and the lever 45 turns counterclockwise against the force of the spring 48 by the component force generated by the contact between the bearings. To allow the bearing 35 to move upwards,
51 presses the downward slope 52 of the lever 47, and the lever 47 rotates clockwise against the force of the spring 48 by the component force generated by the contact between the two, and the upward movement of the pin 51 is stopped. Allow.

As described above, since the developing unit 22 can be biased toward the image carrier 24 around the fulcrum 41, the developing unit 22 can be urged.
A spring for biasing the spring 22 and a supporting member for supporting the spring can be omitted, and there is no need to use a mechanism for locking the developing unit 22. Also, the developing unit 22
Since it is easy to reduce the variation between the weight of the developing unit and the position of the center of gravity, it is possible to reduce the variation in the urging force of the developing unit 22, thereby effectively preventing the vibration of the developing unit 22. And the developing roller 31
58, which drives the agitating blade 32 and the like, is positioned in a direction away from the image carrier 24 with respect to the fulcrum 41, and the developing unit
By attaching the developing unit 22 to the developing unit 22, the own weight of the entire developing unit 22 can be increased, and thus, when the position of the fulcrum 41 is fixed, the urging force for rotating the developing unit 22 toward the image carrier 24 is provided. When the biasing force is set to be smaller than a certain range, the position of the fulcrum portion 41 can be freely changed, thereby increasing the degree of freedom in design. Further, floating of the developing unit 22 due to extreme vibration during transportation or the like can be prevented by the facing portion 62 of the top cover 4. In this case, since the facing portion 62 is formed of a buffer member, even if it interferes with the developing unit 22, there is no damage. Further, since the facing portion 62 faces the developing unit 22 with a predetermined gap s therebetween, vibration generated by applying an external force to the top cover 4 can be prevented from being transmitted to the developing unit 22. . The lower body 1 has a large number of components mounted via the frame 39, has high rigidity to hold heavy components, and has a small vibration because it is placed on a stable table or desk.
This causes harmful vibrations from the lower body 1 to the developing unit.
There is no risk of transmission to the image carrier 22 or the image carrier unit 21.

By making the support shaft 37 made of metal, it is possible to prevent wear of the support shaft 37 due to contact with the metal frame 39. Thus, the developing unit 22 can be positioned with high accuracy. Of course, the support shaft 37 is
A method may be adopted in which the productivity is improved by resin molding integrally with the 30. In this case, a synthetic resin chip that contacts the support shaft 37 is attached to a part of the frame 39,
It may be formed of a synthetic resin to prevent the support shaft 37 from being worn. Also, as shown in FIG.
May be formed with a protrusion 37a at the end of the. The projection 37a comes into contact with the side surface of the frame 39 to act as a guide member when the support shaft 37 is fitted to the fulcrum portion 41, and also prevents the developing unit 22 from oscillating in the left-right direction, and the frame 39 Even if the width is expanded by deformation, the width of the frame 39 can be corrected by fitting the support shaft 37 to the fulcrum portion 41.

Effect of the Invention Since the present invention is configured as described above, the center of gravity of the developing unit is located on the side opposite to the image carrier with respect to the vertical line passing through the fulcrum, so that the developing unit is supported around the fulcrum. The developing unit can be rotated by its own weight, and the developing roller can be brought into contact with the image carrier or the like to be stabilized at a fixed position. It is not necessary to use a supporting member for supporting or a locking mechanism for fixing the developing unit, so that the structure can be simplified and downsized, and the variation between the weight of the developing unit and the position of the center of gravity can be reduced. Since it is easy, the variation of the urging force of the developing unit can be reduced, thereby effectively preventing the vibration of the developing unit. Floating of the developing unit can be prevented by the opposing portion of the upper body, and the opposing portion for preventing the floating opposes the developing unit with a predetermined gap, thereby applying an external force to the upper main body. This has the effect of preventing the resulting vibration from being transmitted to the developing unit.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a vertical sectional side view showing a supporting structure of a basket and an image forming section.
3 is an exploded perspective view showing the relationship between the lower body and the basket, FIG. 4 is a plan view of the basket in which the image forming unit is housed, and FIG. 5 is a view of the developing unit. FIGS. 6 and 7 are partial front views showing the mounting state of the developing unit with the frame in cross section. 1. Lower body, 4 ... Upper body, 22 ... Developing unit, 24 ...
Image carrier, 30: toner container, 31: developing roller, 41: fulcrum, 62: facing part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Sato 570 Ohito, Oni-cho, Tagata-gun, Shizuoka Prefecture Inside the Tokyo Electric Power Company's Ohito Plant (56) References Real Open Sho-61-203756 (JP, U)

Claims (2)

(57) [Claims] 1. A lower body having a support portion for positioning and supporting a bearing of an image carrier and having an opening opened upward, and a cover for opening and closing the opening is provided above the lower body. A developing unit is formed by rotatably mounting a developing roller on a toner container in which toner is stored, and the developing unit is rotatably held with an axis parallel to the axis of the image carrier. A fulcrum, which is located on the image carrier side and above the developing roller with respect to the center of gravity of the unit and makes the developing roller abut on the image carrier, is provided inside the lower main body, and the cover is provided on the cover with the developing unit. A developing device comprising: a facing portion facing a predetermined gap. 2. The developing device according to claim 1, wherein the opposing portion is formed by a buffer member.