JPH02199488A - Developing device - Google Patents

Abstract

PURPOSE:To simplify the structure, to miniature its size and to improve the operability of maintenance by holding a developing unit rotatably on part of an image carrier unit mounted detachably on a frame so that the developing unit can be energized with its own weight toward a carrier. CONSTITUTION:The developing unit 22 which has a developing roller 31 rotatably on a toner container 30 with an axis parallel to the axis of the image carrier 24 is held rotatably on part of the image carrier unit 21 which has the image carrier 24 and is mounted detachably on the frame 39. The fulcrum part 62 for the rotation is closer to the carrier 24 than the centroid of the unit 22 and positioned above the roller 31 to make the unit 22 abut on the carrier 24 with the rotating force based upon its own weight, so that the unit is set at a fixed position stably. Further, the unit 22 is supported by the fulcrum part 62 of the unit 21, so both units can be attached to and detached from the frame by single operation to improve the operability of jam processing and maintenance.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device used in an electrophotographic apparatus.

BACKGROUND 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 to the image carrier through the developing roller. . Conventionally, as described in Japanese Patent Application Laid-open No. 62-192771 and Japanese Patent Application Laid-open No. 63-144370, means for maintaining a constant relative position between an image carrier and a developing roller have been considered. Japanese Patent Publication No. 1986-1927
The content described in Japanese Patent No. 71 is such that the case of the developing unit is movably supported by rollers, the developing unit is biased toward the image carrier by a spring, and is pressed downward by another spring. Moreover, the content described in Japanese Patent Application Laid-Open No. 63-144370 is that a developing casing holding a developing roller is rotatably supported by a support shaft, and this developing casing is biased toward the image carrier side by a spring. It is.

Problems to be Solved by the Invention The invention described in JP-A-6:2-192771 discloses that if 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 increases. Becomes more likely to fluctuate. Therefore, it is necessary to increase the strength of the spring as well as the strength of the support portion that supports the spring, and the number of components increases, which increases the overall weight. Similarly, in the device disclosed in Japanese Patent Application Laid-Open No. 63-144370, the force of the spring that biases the developer casing must be increased. Further, since the spring has a large variation in force, the influence is large, and since a space is required for arranging the spring and a support member that supports the spring, there is a problem that the size of the spring increases.

Means for Solving the Problems A developing unit in which a developing roller is rotatably attached to a toner container in which toner is stored is provided, and an image carrier unit having an image carrier and detachably attached to a frame is provided. A fulcrum part that rotatably holds the developing unit with an axis parallel to the axis of the image carrier is located on the image carrier side with respect to the center of gravity of the developing unit and above the developing roller. It was set up as follows.

Function Since the center of gravity of the developing unit is located on the opposite side of the image carrier with respect to the vertical line passing through the fulcrum, the developing unit can be biased toward the image carrier around the fulcrum. The unit can be rotated by its own weight, and the developing roller can be brought into contact with the image carrier or a support that supports the image carrier, thereby stabilizing it in a fixed position. Furthermore, since the developing unit is supported by the fulcrum of the image carrier unit, the image carrier unit and the developing unit can be attached to and detached from the frame in one motion, making it possible to perform jam removal and maintenance work. can improve sex.

Example An embodiment of the present invention will be described based on the drawings.

FIG. 2 is a longitudinal side view showing the overall structure. In the figure, 1 is a lower body that constitutes a part of the main body of the electrophotographic printer. This lower body 1 connects a base cover 2 and an upper cover 3. One end of a top cover 4 serving as an upper body is attached to the upper part of the lower body 1 so as to be vertically movable. A power source 5 and a circuit board 6 are attached to 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, and at the end of this paper transport path 8, the paper is transported to a paper ejection tray 9 formed on the top surface of the top cover 4. A paper ejection path 10 for ejecting the paper toward is connected to this connecting portion, and a switching unit 11 for switching the ejection path of the paper to the side surface of the lower main body 1, which is on the extension surface of the paper ejection path 10 or the paper conveyance path 8, is connected to this connection part. It is provided. Further, the paper conveyance path 8 includes a paper feed roller 12 that contacts the uppermost sheet of the paper feed cassette 7, a start sensor 13 that optically detects the conveyed paper, and a detection sensor 13 that detects the paper that is being conveyed. A registration roller 14 whose rotational movement is controlled by a signal, a transfer section 15 that transfers a developed image on an image carrier 24 to a sheet of paper, which will be described later, a peeling section 16 that separates the paper from the image carrier 24, and a high-voltage power source 17. and a fixing section 18 that clamps the paper that has passed through the transfer section 15 and fixes the transferred image on the paper are sequentially arranged from upstream to downstream.

Further, a basket 19 with vertical openings located above the paper transport path 8 is attached to the upper cover 3, and an image forming unit 2 is detachably housed in the basket 19.
0 consists of an image carrier unit 21 and a developing unit 22. The image carrier unit 21 includes an image carrier 24 rotatably mounted on both sides of a support 23, a charging section 25 that charges the image carrier 24, and a charging section 25 that charges the image carrier 24 and exposes the image carrier 24 to light on its outer periphery. A static eliminator 26 that makes the charge uniform and a waste toner container 2
7 is attached to the support body 23, and a blade 2 is attached to the waste toner container 27 to scrape off the waste toner adhering to the image carrier 24.
8 and a roller 29 that conveys the scraped off waste toner toward the back of the waste toner container 27. The developing unit 22 includes a developing roller 31 and a stirring blade 32 that stirs the toner in a toner container 30 containing toner.
(See Figure 5). Furthermore, flange-shaped protrusions 31a are formed at both ends of the developing roller 31 to contact the outer circumferential surfaces of both ends of the image carrier 24. Further, the image carrier 24 is provided on the inner surface of the top cover 4.
An optical section 33 is attached to scan the light beam on the photosensitive surface of the photosensitive surface.

Next, the mounting structure of the basket 19 and the image forming section 20 is shown in FIGS. 1, 3, and 4. FIG. 1 is a longitudinal sectional side view showing the support structure for the basket 19 and the image forming section 20, FIG. 3 is an exploded perspective view showing the relationship between the lower main body 1 and the basket 19, and FIG. 4 is an exploded perspective view showing the support structure for the image forming section 20. FIG. 3 is a plan view of the basket 19. 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 . A guide groove 36 for vertically movably guiding a bearing 35 protruding from the outside and supporting the image carrier 24, and a guide groove 38 for vertically movably guiding a support shaft 37 protruding from both sides of the toner container 30. It is formed. Further, the transfer portion 15 and the peeling portion 16 are positioned on a frame 39 fixed to the upper cover 3 and fixed by screws, and the bearing 35 and the support shaft 37 are positioned on this frame 39. Support portions 40 and 41 are formed to support the image carrier unit 21, and a stopper 42 is provided upright to abut the lower ends of the supports 2 and 3 of the image carrier unit 21. These support portions 40, 41 are in the form of a concave portion with an opening at the upper portion and have a shape that widens toward the upper portion. Furthermore, the frame 39 is provided with a locking means 43 that elastically engages with the image carrier unit 21. This locking means 43 includes a lever 45 that rotates around a support shaft 44 and a lever 47 that rotates around a support shaft 46 . The upper portions of these levers 45, 47 are urged in opposite directions by the urging force of a spring 48. A downward slope 49 for pressing the bearing 35 against the bottom of the support portion 40 of the frame 39 is formed on the upper part of one lever 45, and a slope 50 whose slope direction is changed upward from this slope 49. The lever 47 has the image carrier unit 2
A downward slope 52 that presses the bottle 51 protruding from the outer surface of the first support body 23, and a slope 53 whose slope direction is changed upward from this slope 52 are formed. Furthermore, a handle 54 is integrally formed on the housing of the static eliminator 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 when the handle 34 of the basket 19 is grasped, the fingers of the same hand can be hung thereon. Further, these handles 54 and 56 are formed with upward pressing portions 55 and 57 and downward finger hook portions 55a and 57a for hanging fingers. Further, on the lower surface of the housing of the optical section 33, as shown in FIG. 1, a proximal section 61 is formed which faces the upper edge of the support body 23 of the image carrier unit 21 with a predetermined gap therebetween. .

Thus, fulcrum portions 62 that rotatably hold the support shaft 37 of the developing unit 22 with an axis parallel to the axis of the image carrier 24 are formed on both sides of the support 23 of the image carrier unit 21. There is. These fulcrum portions 62 are formed by U-shaped notches, and the support shaft 37 can be attached and detached. Further, these fulcrum portions 62 are located closer to the image carrier 24 than the center of gravity of the developing unit 22 and above the developing roller 31 . Further, a motor 58, which is a drive source for driving the developing roller 31 and the stirring blade 32, is fixed to the developing unit 22, and a power input terminal 59 connected to the motor 58 projects downward. established,
A knife-shaped connector 60 that elastically holds these power input terminals 59 is fixed to the inner surface of the frame 39. This connector 60 is connected to a power source. The motor 58 is positioned in a direction away from the image carrier 24 with respect to the fulcrum portion 41 .

In such a configuration, when performing jam removal or maintenance, the top cover 4 is rotated upward to open the upper surface of the upper cover 3, and in this state, the handle 34 is grasped to move the basket 19 to the image carrier unit 21 and the upper cover 3. When it is pulled up together with the developing unit 22, the paper conveyance path 8 is opened. Alternatively, the image carrier unit 21 and the developing unit 22 can be moved independently with the basket 19 positioned inside the upper cover 3 by hooking the fingers on the finger hooks 55a and 57a of the handle 54 and 56 and pulling up. It can also be removed.

When disassembling a jam or assembling after maintenance, insert the bearing 35 of the image carrier unit 21 into the guide groove 36 of the basket 19 taken out from the upper cover 3, and insert the support shaft 37 of the developing unit 22 into the guide groove 38. While inserting, the basket 19 is fitted into the fulcrum part 62, the handle 34 of the basket 19 is gripped, and the bearing 35 and the support shaft 37 are fitted into the support part 40, 41 of the frame 39, and the basket 19 is housed in the upper cover 3. Alternatively, the guide grooves 36 and 38 of the basket 19 housed in the upper cover 3 and the support part 4
The image carrier unit 21 and the developing unit 22 are housed in the basket 19 after fitting the bearing 35 or the support shaft 37 to the 0.41. At this time, the support shaft 37 is fitted into the support part 62, and the bearing 35 whose movement in directions other than the vertical direction is regulated by the guide groove 36 is supported by the upward slope 50 of the lever 44. slope 53
However, while holding the handle 34 of the basket 19, the user can press the pressing portion 55 of the handle 54 with his or her fingers. By this operation, the lever 45 is moved against the spring 48 by the force generated by the contact between the bearing 35 and the slope 50.
It rotates counterclockwise against the force, allowing the bearing 35 to move downward. Similarly, the bottle 51 is also supported by the slope 53 of the lever 47, and by pushing down the pressing part 55 of the handle 54, the lever 47 resists the force of the spring 48 with the force generated by the contact between the bottle 51 and the slope 53. to allow the bottle 51 to move downward. Then, the lever 45, which has returned to its original state due to the restoring force of the spring 48, presses the bearing 35 against the bottom of the support part 40 with its downward slope 49, and similarly, the lever 47 presses the bottle 51 downward with its downward slope 52, supporting it. The lower edges of both sides of the body 23 are pressed against the stopper 42.

The developing unit 22 is supported by its own weight with a support shaft 37 positioned at a fulcrum portion 41, but this fulcrum portion 41 is located above the developing roller 31 and closer to the image carrier 24 than the center of gravity of the developing unit 22. As a result, the developing unit 22 rotates clockwise about the fulcrum portion 41, and the protrusions 31a provided at both ends of the developing roller 31 come into contact with the outer periphery of the end portion of the image carrier 24. As a result, the developing unit 22 is attached to the frame 39 in a stable state with a constant gap at the intermediate portion between the image carrier 24 and the developing roller 31.

As described above, the image carrier 21 and the developing unit 22 are
Since it is stably attached to the frame 39 that positions and fixes the transfer section 15 and the peeling section 16, the relative position of the image carrier 24 with respect to the transfer section 15 and the peeling section 16 can be determined accurately.

Also, when handling jams or maintaining the basket,
9 is pulled up, but in this process the bearing 35 is pulled up by the lever 4.
5, the lever 45 rotates counterclockwise against the force of the spring 48 due to the force generated by the contact between the two, allowing the bearing 35 to move upward;
Similarly, the bottle 51 presses the downward slope 52 of the lever 47, and the lever 47 rotates clockwise against the force of the spring 48 due to the force generated by the contact between the two, and the bottle 51
Allow upward movement.

As described above, since the developing unit 22 can be biased toward the image carrier 24 around the fulcrum portion 62, the spring for biasing the developing unit 22 and the support member that supports the spring can be omitted. Developing unit 2
There is no need to use a mechanism to lock 2. Further, since it is easy to reduce variations in the weight of the developing unit 22 and the position of the center of gravity,
yr7) Variations can be reduced, thereby effectively preventing vibration of the developing unit 22, and furthermore, the motor 58 that drives the developing roller 31, stirring blade 32, etc. can be By mounting the developing unit 22 in a direction away from the carrier 24, the weight of the entire developing unit 22 can be increased, and as a result, when the position of the fulcrum portion 62 is kept constant, the developing unit 22 The position of the fulcrum part 62 can be freely changed by increasing the biasing force for rotating the image carrier 24 toward the image carrier 24 and setting the biasing force below a certain range, thereby increasing the degree of freedom in design. can be increased.

In addition, as shown in FIG.
The chip 63 may be fixed with a screw or the like. Thereby, when the fulcrum portion 62 wears out, only the tip 63 can be replaced as long as the life of the image carrier unit 21 remains.

Effects of the Invention Since the present invention is configured as described above, the center of gravity of the developing unit is located on the opposite side of the image carrier with respect to the vertical line passing through the fulcrum. This allows the developing unit to be rotated by its own weight, and the developing roller to be brought into contact with the image carrier or a support that supports the image carrier, etc., and to be stabilized in a fixed position. Therefore, there is no need to use a spring, a support member that supports the spring, a lock mechanism that fixes the developing unit, etc., and the structure can be simplified and downsized, and the weight and center of gravity of the developing unit can be reduced. Since it is easy to reduce the variation in the biasing force of the developing unit, it is possible to reduce the variation in the biasing force of the developing unit, thereby effectively preventing vibration of the developing unit. Since it is supported by the fulcrum of the unit, the image carrier unit and developing unit can be attached to and detached from the frame in one motion.
This has the effect of improving the workability of jam removal and maintenance.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG.
The figure is a longitudinal side view showing the overall structure, Figure 3 is an exploded perspective view showing the relationship between the lower main body and the basket, Figure 4 is a plan view of the basket housing the image forming section, and Figure 5 is a view of the developing unit. FIG. 6 is a side view showing a part of an image carrier unit according to a modification of the present invention. 21... Image carrier unit, 22... Developing unit, 24... Image carrier, 30... Toner container, 31...
...Developing roller, 39...Frame, 41...Fully point, 58...Drive source procedure amendment 1, Indication of incident Patent application No. 20346/1999, Title of invention Developing device 3, Make corrections Relationship with the Patent Applicant's Case (Volunteer) Written Amendment to Patent Application No. 1-20346 Regarding this application, the description and drawings in the specification are amended as follows. Note 1. In the specification, page 8, line 14 to line 15 [
The bearing...support parts 40, 41J are corrected to ``a support part 40J that positions and supports the bearing 35.'' Support part 4
0.41J is corrected to "this support part 40". None 3. In the specification, on page 12, lines 11 to 17, "to store the bearing 35" has been changed to "to store the basket 19 in the upper part while fitting the bearing 35 into the support part 40 of the frame 39." Store in cover 3. Alternatively, the bearing 35 of the basket 19 housed in the upper cover 3 is fitted into the guide groove 36 and the support part 40, and the support shaft 37 is fitted into the guide groove 38, and then the image carrier unit 21 and the developing device are connected. The unit 22 is stored in the basket 19. ”. Add ", 62... fulcrum part". 9.Amend the drawings in Figures 1, 3, and 4 as shown in the attached sheet. 4. In the specification, "fulcrum portion 41" in the third to fourth lines of page 14 is corrected to "F fulcrum portion 62". 5°, page 14, lines 4 and 5, "fulcrum portion 41J" is corrected to "fulcrum portion 62." 6° is corrected to "fulcrum portion 62" on page 14, line 7 in the specification. "Fulcrum portion 44J 7, first point on page 18 in the specification" is deleted. On the 6th line [4 ■... Support 8゜In the specification, at the end of the 17th line on page 18,

Claims (1)

[Claims] A developing unit in which a developing roller is rotatably attached to a toner container in which toner is stored is provided, and the image carrier is attached to a part of the image carrier unit that has an image carrier and is detachably attached to a frame. A fulcrum portion for rotatably holding the developing unit with an axis parallel to the axis of the developing unit is provided at a position closer to the image carrier than the center of gravity of the developing unit and above the developing roller. Characteristic developing device.