JPS622611Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a release position of a member, such as a squeeze roller, which is removably attached to a predetermined position near a photosensitive drum of an electrophotographic copying machine.

The photoreceptor drum of an electrophotographic copying machine includes various chargers for charging and discharging the photoreceptor drum, a developing device for visualizing the electrostatic latent image formed by the exposure device, and a transfer paper for transferring the visible image. A transfer device for transferring images onto the surface of the photosensitive drum, a cleaning device for preparing the surface of the photoreceptor drum for the next copying process, and the like are arranged opposite to each other near the entire circumferential surface of the photosensitive drum. In particular, devices that are close to the photoreceptor drum and that maintain a predetermined position in close proximity at all times include rotating rollers such as a developing roller, squeeze roller, magnetic brush roller, and cleaning foam roller, developing electrode plates, separation claws, and cleaning blades. There are various unit parts. Although these members have different structures, they are all close to or in contact with the photoreceptor drum. Therefore, when the photoreceptor drum is removed from its normal position, for example, when replacing the photoreceptor drum, regularly inspecting the copying machine, repair work, or when there is paper jam around the photoreceptor,
The surface of the photoreceptor drum may be damaged by unit members that come into contact with or come close to the photoreceptor drum. Conventionally, in order to eliminate such inconveniences, when removing the photoreceptor drum, the unit member u that is in contact with or in the vicinity of the photoreceptor drum is separated from the surface of the photoreceptor drum, and then the photoreceptor drum is removed from the copying machine main body. For removal, the unit member u is fitted with a release device which separates this member from the predetermined position. A conventional release device A for a unit member such as a squeeze roller is constructed as shown in FIGS. 3 and 4. A squeeze roller 21, which is located close to the lower surface of the photosensitive drum 13, is attached to one end of a roller support arm B whose center portion is pivotally connected to the substrate 11. The other end of the roller support arm B is biased by a tension spring B1, and this biasing force is configured to rotate the squeeze roller 21 around a support shaft B2 toward the photosensitive drum.
Bearings 211 having a radius larger by a predetermined amount than the squeeze roller are attached to both ends of the squeeze roller 21, and these bearings 211 are in contact with the photosensitive drum 13. Therefore, the developer adhering to the photoreceptor drum 13 and the visualized toner image face the squeeze roller 21, and when they pass through this, the developer on the photoreceptor drum 13 is compressed to a predetermined amount with a constant developer thickness. ie squeezed. In the figure, 212 is a scraper for scraping off the developer squeezed from the surface of the photoreceptor drum 13 by the squeeze roller 21. A pressing force is applied to rotate it counterclockwise in the figure. With this configuration, squeeze roller 2
1 is disposed at a predetermined position H (indicated by a one-dot chain line in the figure), but the roller support arm B further has a squeeze roller 21 detached from the predetermined position H against the biasing force of a tension spring B1. A locking protrusion B3 is provided, and a push piece C2 protruding from the rotation shaft C1 of the release lever C is in contact with this locking protrusion B3. The release lever C is pivotally mounted to the base plate 11 via a rotation shaft C1 that rotates integrally with the release lever. A fitting protrusion C3 that fits into a fitting hole D1 provided in the face plate D is provided at one end of the release lever C. This face plate D is the photosensitive drum 13
The center support shaft 13a of the photoreceptor drum 13 is fitted to support the photoreceptor drum 13 at a fixed position on the substrate 11, and the photoreceptor drum is mounted on the substrate 11. Therefore, when the photosensitive drum 13 is removed from the central support shaft 13a, this face plate D is removed from the substrate 11 in advance. In the figure, C4 is a tension spring biased to rotate the release lever C clockwise, and this spring is configured to have a stronger bias force than the tension spring B1 of the roller support arm B. For this purpose, hold the clamping piece C5 on the fitting protrusion C3 side of the release lever C and rotate the release lever C counterclockwise about the rotation axis C1 against the biasing force of the tension spring C4. By operation, the fitting protrusion C3 and the fitting hole D1
The face plate D is attached by fitting and connecting them. At this time, the push piece C2, which had been receiving a clockwise moment due to the biasing force of the tension spring C4, is rotated in the opposite direction, so the locking protrusion B3 of the roller support arm B is released from the restraint from the push piece C2. As a result, the roller support arm B rotates clockwise around the support shaft B2 by the biasing force of the tension spring B1, rotates the squeeze roller 21 toward the photosensitive drum 13 side, and brings it into the predetermined position H. have it arranged. When connecting the release lever C to the face plate D by such an operation, the operator must hold the gripping piece C5 of the release lever with one hand.
It is necessary to grasp and rotate it counterclockwise, and at the same time, use the other hand to fit the mating protrusion 11a on the base plate 11 into the mating hole D2 on the face plate D, which requires operation with both hands. It is. In addition, in this release device A, when the release lever C is removed from the face plate D, the squeeze roller 21 does not naturally separate from the photoreceptor drum 13 due to its own weight;
4 has a stronger biasing force than the tension spring B1, and is separated from the tension spring B1. Therefore, if the biasing force of both tension springs C4 and B1 deteriorates due to long-term use and changes in strength, the above-mentioned configuration will no longer work. Sometimes cases may arise. In order to eliminate this inconvenience, the face plate D can be attached to the substrate 11 with one hand, and the release lever and roller support arm are pivoted on the same axis so that the squeeze roller is separated from the photoreceptor drum by its own weight. The face plate may apply a pressing force to the release lever so that the roller support arm is rotated via the release lever in a direction opposite to such movement due to its own weight.

Therefore, in this invention, the unit members are separated from the photoreceptor drum before the photoreceptor drum is removed from the main body of the copying machine, and each unit member is placed in a predetermined position simply by attaching the face plate to the substrate. An object of the present invention is to provide a release device configured to be able to release by applying a pressing force to a release lever at the same time as the release lever is attached.

According to this invention, the configuration of the release device is simplified and the number of parts is fewer than that of the conventional release device, thereby reducing costs. It has the advantage of being able to be operated with one hand, and since the unit member is moved away from the operating position facing the photoconductor drum to the retracted position, there is an advantage that damage to the photoconductor drum can be prevented and the life of the photoconductor drum can be extended.

Before explaining this invention, an example of an electrophotographic copying machine to which the releasing device of the invention is applied will be explained first.

In FIG. 2, an electrophotographic copying machine, designated as a whole by reference numeral 10, has a base plate 11 fixed to a hollow stand 12. A photoreceptor drum 13 having a photoconductor layer on its circumferential surface is located above the stand 12
is connected to a suitable rotation transmission device by a driving motor 14 shown to the left of the photoreceptor drum 13;
For example, it is designed to be driven in the direction of arrow a via a chain sprocket device.

Around the photoreceptor drum 13, there is a charger 15 for image formation and transfer, a transfer paper separation device 16 for separating the transfer paper from the surface of the photoreceptor drum 13 and guiding it in a predetermined direction, and a focusing light transmission device. body (product name:
A developing device on the surface of the photoreceptor drum that has passed through the exposure device 17 consisting of a row of self-opening devices, a charger 18 for static elimination, a liquid developing device 19, a cleaning blade 20 whose free end can move toward and away from the photoreceptor drum 13, and the developing device 19. Squeeze rollers 21 for regulating the liquid layer to a predetermined thickness are arranged in this order. The charger 15 for image formation and transfer uniformly charges the entire surface of the photoreceptor drum 13 before slit exposure is performed by the exposure device 17, and also charges the visible image, that is, the toner image, on the photoreceptor drum 13 to a transfer paper. It is attached close to the surface of the photoreceptor drum in order to transfer it to the side. Similarly, a static eliminating charger 18 is also provided near the photosensitive drum 13 so as to eliminate static electricity from the surface of the photosensitive drum 13. The developing electrode 37 constituting the developing device 19 is used to remove toner particles adhering to areas other than the electrostatic latent image when the electrostatic latent image on the photoreceptor drum 13 is visualized with toner particles. It is usually placed close to the surface of the photoreceptor drum 13. The cleaning blade 20 removes the developer adhering to the surface of the photoreceptor drum 13, and the squeeze roller 21 removes the developer while retaining the visualized toner image on the surface of the photoreceptor drum 13. This is a device that adjusts the amount to a constant value, and both are installed close to the photoreceptor drum.

The photosensitive drum 13 starts rotating when the main switch of the copying machine is turned on.
When a print button is pressed, the photosensitive drum 13 is moved from the right-hand position shown in the figure to the left-hand position at a speed synchronized with the photosensitive drum 13 , and the original image is projected onto the photosensitive drum 13 via an exposure device 17 .

The transfer paper fed by the pair of registration rollers 56 and 57 has a few millimeters of one side edge attached to the photoreceptor drum 1.
The protruding portion of the leading edge of the transfer paper that has come into contact with the photoreceptor drum 13 and passed through the transfer device 15 is scooped up by the guide portion 66 of the separation device 16, and as the transfer paper advances further, this protruded portion is The transfer paper is sandwiched between the turn roller 67 and the turn belt 68, and is separated from the photoreceptor drum. The separated transfer paper passes over a guide plate 69 and is delivered to a paper discharge table 7 by a pair of paper discharge rollers 70 and 71.
2 is discharged on top.

In the above-mentioned electrophotographic copying machine 10, there is a squeeze roller as the unit member u, and in particular, the bearings 211 at both ends of the squeeze roller 21 are in contact with both ends of the photoreceptor drum, and the squeeze roller 21
However, when removing the photoreceptor drum 13 from the central support shaft 13a, if the bearing 211 is pulled out in that state, there is an inconvenience that the bearing 211 will damage the photoreceptor drum surface. Easy to release.

This invention relates to a release device A for disposing a unit member U, such as the squeeze roller 21, at a predetermined position H so that it can approach and separate, and is constructed as shown in FIGS. 5, 6, and 7.

In FIG. 5, a central support shaft 13a, which supports the photosensitive drum 13, is mounted on the parallel substrates 11, 11, each of which is pivotally mounted by a bearing 111. The base plate 11 on the front side is configured such that a face plate 74 to which a bearing 111 is fixed is screwed with a drum mounting screw 131, and the base plate 11 on the rear side has a bearing 111 and a central support shaft at a position away from the bearing. Support frame 11 that cantilevers support 13a
2 is permanently installed. The photosensitive drum 13 has a front flange 113 that is removably attached to the central support shaft.
and a rear flange 114 fixed to the central support shaft. A squeeze roller 21 and a pair of bearings 211 for the squeeze roller are integrally attached to the support shaft.
11 is in contact with the peripheral surfaces of both flanges 113 and 114, the squeeze roller 21 is configured to be able to rotate at a predetermined position H by rotation of the support shaft. This bearing 211 is in a position where the surface of the photoreceptor drum 13 will be damaged if the photoreceptor drum 13 is separated from between the flanges 113 and 114 in this state. A release device A is installed to prevent this. A release lever 75 having a pressure contact portion 751 is pivoted to a support shaft 73 protruding from the base plate 11 and is rotated clockwise in FIG. 6 by a pressing force F received by a protrusion 741 of the face plate 74. . Furthermore, it is pivotally connected to the support shaft 73 in parallel with the release lever 75, and its connecting end 76
1 to the connection end 752 of the release lever 75 and the elastic member 7
A roller support arm 76 as a unit arm u1 connected via a tension spring 771 as a unit arm u1.
A squeeze roller 21 is pivotally mounted on the other end in a direction parallel to the surface of the photoreceptor drum. The roller support arm 76 has a tendency (indicated by an arrow in the figure) to position its center of gravity on the vertical line of the support shaft 73 due to the weight of the squeeze roller 21;
4 is mounted in a fixed position by fitting the mating hole 742 of the face plate into the mating protrusion 11a on the substrate 11, the protruding part 741 of the face plate applies a pressing force F to the pressure contact part 751 facing thereto. The protruding portion 741 may be integrally constructed with the face plate so as to protrude from the face plate 74 in an inclined manner, or may be formed of a leaf spring S so as to elastically generate the pressing force F.
This has the advantage that the protruding portion 741 can be reliably pressed against the pressing portion 751. When the release lever 75 rotates clockwise in this manner, the roller support arm 76 elastically places the squeeze roller 21 at a predetermined position H facing the photoreceptor drum via the tension spring 771 as an elastic member. Next, when the face plate 74 is removed from the base plate 11, the pressing force F from the protruding part 741 is removed from the pressure contact part 751, so that the release lever 75 and the tension spring 771 are connected to each other on the support shaft 73.
The roller support arm 76 connected to the roller support arm 76 operates only by its own rotational behavior due to its own weight. That is, due to its own weight, the squeeze roller 21 is rotated away from the predetermined position H, and the center of gravity is moved in the direction perpendicular to the support shaft 73. After this, the photoreceptor drum 13 is pulled out from the center support shaft 13a, and the squeeze roller 2 is fully tightened.
1 is spaced apart from the photoreceptor drum surface, so that the photoreceptor drum surface will not be damaged. In this case, the squeeze roller 21 is replaced by a scraper 212 made of a thin Mylar sheet for scraping off the adhering developer.
Since rotational force can be applied in the counterclockwise direction even if the squeeze roller 21 is removed from the predetermined position by removing the face plate 74, there is an advantage. This embodiment has one tension spring 771 as an elastic member, a roller support arm 76 as a unit arm, and a release lever 75 as compared to the conventional embodiment shown in FIGS. There is an advantage that only one support shaft is required for pivotally mounting the roller, and that the structures of the release lever 75 and the roller support arm 76 are also simplified. Furthermore, the squeeze roller 21 is rotated around the support shaft 73 by the pressing force F applied to the pressure contact portion 751 and is elastically disposed at the predetermined position H, while the squeeze roller 21 is moved away from the predetermined position H to the retracted position I. Since the roller is operated by its own weight, it has the advantage of a reasonable structure and stable operation over a long period of time without deterioration of function.

This invention biases the elastic member 77 interposed between the release lever 75 and the unit arm u1 when the protruding part 741 of the face plate and the pressure contact part 751 of the release lever come into pressure contact with each other, and elastically releases the unit member u such as the squeeze roller. As long as the unit member U is disposed at a predetermined position H and the unit member U is removed from the predetermined position when the face plate and the press-contact portion are separated, the deformation is free. For example, as shown in FIGS. 8 and 9, a helical spring 772 is fitted and attached as an elastic member to the squeeze roller shaft 213 of the roller support arm 76, and one end of the helical spring 772 is locked near the squeeze roller shaft of the roller support arm 76. Then, the other end is locked to the connection end 752 side of the release lever 75. When the protruding portion 741 of the face plate applies a pressing force F to the pressure contact portion 751 of the release lever 75 in this state, the release lever 75 receives a clockwise moment, which is transferred onto the roller support arm 76 via the helical spring 772. to the squeeze roller shaft 213. Therefore, the squeeze roller 21 is elastically disposed at the predetermined position H. Furthermore, when the pressing force F is removed, the squeeze roller 21 is retracted from the predetermined position H to the retracted position I, and the release lever 75 is rotated counterclockwise. If the release lever 75 is formed to have a certain position, the release lever 75 is supported with the pressure contact end 751 positioned above the support shaft 73. In this embodiment, the helical spring 77
2 can be used, which has the advantage of making the whole structure compact. Furthermore, compressed rubber 773 can also be used as the elastic member in this embodiment. That is, as shown in FIG. 10, the connecting end 752 of the release lever 75 and the roller support arm 76 facing thereto
A compressed rubber 773 is interposed between them, and one end of the compressed rubber 773 is fitted and adhered to a receiving portion 762 recessed in the end of the roller support arm 76.
A receiving portion 753 whose other end is recessed in the connecting end 752
It is inlaid and pasted. Therefore, the release lever 75 rotates clockwise when the pressing force F from the protrusion 741 is applied, so that the compressed rubber 77
3, the squeeze roller 21 is elastically disposed at a predetermined position H.

Although the above-mentioned unit member u and unit arm u1 are provided in a pivotally connected state, the present invention is not limited to this, and a configuration in which a cleaning blade or various chargers (not shown) are fixed to the unit arm u1 as the unit member u is also possible. can be used.
Furthermore, although the unit member u can be removed from the predetermined position H by its own weight in each of the above-described embodiments, the present invention is not limited to this. For example, as shown in FIG.
For example, if the transfer charger 15 is fixedly installed and a tension spring 153 is attached to pull it up from the predetermined position H to the retracted position I, the unit member u can be operated against its own weight.

This invention forcibly moves the various unit members U disposed facing each other over the entire circumferential surface of the photosensitive drum 13 from a predetermined position H to the retracted position I before the photosensitive drum 13 is attached or detached. body drum 1
3 can be easily attached and detached, and also has the effect of preventing damage to the photosensitive drum 13.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view showing an example of an electrophotographic copying machine in which the present invention is implemented, and FIG. 2 is a vertical cross-sectional view of the central portion of the same electrophotographic copying machine. FIG. 3 is a front view of a conventionally used release device, FIG. 4 is a perspective view of the same release device, FIG. 5 is a cross-sectional view showing the mounting state of the release device to which this invention is applied, and FIG.
8, 10 and 11 are front views, FIGS. 7 and 9, respectively, of different embodiments of the same release device.
The figures are side sectional views taken along line XX in FIG. 6 and line Y-Y in FIG. 8, respectively. DESCRIPTION OF SYMBOLS 11... Board, 73... Support shaft, 74... Face plate, 741... Projection part, 75... Release lever,
751... Pressing end, 77... Elastic member, A... Release device, F... Pressing force, H... Predetermined position, u...
Unit member, F...pressing force, H...predetermined position,
u...Unit member, u1...Unit arm,
S...Plate spring.

Claims (1)

[Claims for Utility Model Registration] 1. A unit member that is removably provided at a predetermined position facing the photosensitive drum and is provided with an arm-shaped unit arm, and a release lever that restricts rotation of the unit member. The release lever is pivotally mounted, and the release lever has a press-contact portion that is pressed against a protruding portion of a face plate that removably supports the photoreceptor drum on the substrate, and the unit member is moved into a predetermined position by attaching and detaching the face plate to and from the substrate. A release device configured so that it can be attached to and separated from a position. 2. The release device according to claim 1, wherein the unit member and the release lever are connected by an elastic member. 3. The release device according to claim 1 or 2, wherein the unit member is detachable from a predetermined position by its own weight. 4. The protruding portion of the face plate is formed of a leaf spring.
or the release device according to paragraph 3.