Patent Application
20250237990
This application is based on and claims the benefit of priority from Japanese patent application No. 2024-007186 filed on Jan. 22, 2024, which is incorporated by reference in its entirety.
The present disclosure relates to a drive transmission device and an image forming apparatus.
A main body side drive unit for transmitting a driving force to a photosensitive drum of an image forming apparatus is known. An axial center (coupling) of a drive input gear of the main body side drive unit is supported by a bearing attached to a main body frame sheet metal. The main body side drive unit includes a lock member having a cam portion, and the bearing has another cam portion which is in contact with the cam portion of the lock member. The cam portion of the lock member is turned in a reciprocating manner while in contact with the cam portion of the bearing such that the main body side drive unit is coupled and uncoupled to the photosensitive drum.
Incidentally, in the image forming apparatus, in order to form a good image, it is required to rotate the photosensitive drum with high accuracy without causing vibration (shaft deviation). In order to rotate the photosensitive drum with high accuracy, it is effective to connect the axial center (coupling) of the drive input gear as close as possible to the photosensitive drum.
However, in the above-described technique, since the bearing having the cam portion is attached to the body frame sheet metal, the axial center (coupling) of the drive input gear must be extended by a thickness of the bearing. Therefore, in the above-described technique, the photosensitive drum tends to vibrate easily, and a good image cannot be formed. Further, in the above-described technique, it is necessary to prepare the bearing that is a separate part from the body frame sheet metal, or to attach the bearing to the body frame sheet metal, thereby increasing the manufacturing cost of the body side drive unit.
A drive transmission according to the present disclosure is arranged to face a drive transmitted portion across a metal plate. The drive transmission device includes a gear part, a coupling part, a biasing member and a retracting part. The gear part is coupled to a drive source, and rotates around an axis by a driving force of the drive source. The coupling part is formed into a cylindrical shape, penetrates a through-hole of the metal plate, is connected to the drive transmitted portion, and rotates around the same axis of the gear part. The biasing member biases the gear part and the coupling part to a direction close to the drive transmitted portion. The retracting part is formed into an annular shape through which the coupling part penetrates, and rotates around the same axis as the coupling part in a reciprocating manner. The metal plate has at least two inclined parts which are arranged across the through-hole, and protrude in a direction away from the drive transmitted portion. The inclined part is formed by deforming a part of the metal plate. The retracting part rotates in one direction while in contact with the inclined part to move the gear part and the coupling part in the direction away from the drive transmitted portion against a biasing force of the biasing member.
An image forming apparatus according to the present disclosure includes the drive transmission device according
The above and other objects, features, and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present disclosure is shown by way of illustrative example.
With reference to the attached drawings, embodiments of the present disclosure will be described below. Fr, Rr, L, R, U and D shown in the drawings indicate the front, rear, left, right, upper and lower. Although terms showing direction and position are used herein, these terms are used for convenience of description and do not limit the technical scope of the present disclosure.
[Image forming apparatus] With reference to
The image forming apparatus 1 forms an image on a sheet P by an electrophotographic method. The image forming apparatus 1 includes an apparatus main body 2 constituting a substantially rectangular parallelepiped appearance. In the lower portion in the apparatus main body 2, a sheet feeding cassette 3 in which sheets P (medium) are stored is provided. On the upper surface of the apparatus main body 2, a sheet discharge tray 4 on which the image-formed sheet P is received is provided. A conveyance path 8 along which the sheet P is conveyed from the sheet feeding cassette 3 to the sheet discharge tray 4 is formed inside the apparatus main body 2. A sheet feeding device 5 is provided at the upstream end of the conveyance path 8, an image forming device 6 is provided at the midstream portion of the conveyance path 8, and a fixing device 7 is provided at the downstream portion of the conveyance path 8. The sheet P is not limited to a paper sheet but may be made of resin or the like.
The image forming device 6 includes a toner container 10, a drum unit 11, and an optical scanner 12. The toner container 10 contains, for example, black toner (developer). The drum unit 11 includes a photosensitive drum 13 and a charging device 14. The charging device 14, a developing device 15, a transfer roller 16 and a cleaning device 17 are arranged around the photosensitive drum 13 in the order of the image forming process. The transfer roller 16 is in contact with the photosensitive drum 13 from the lower side to form a transfer nip. The toner may be a two-component developer in which toner and carrier are mixed, or a one-component developer composed of magnetic toner.
The image forming apparatus forms an image on the sheet P based on image data outputted from an external terminal (personal computer, or the like). A control part (not shown) provided in the image forming apparatus 1 controls the image forming apparatus 1 based on the input image data, and the image forming process is executed as follows.
The charging device 14 charges the surface of the photosensitive drum 13. The photosensitive drum 13 is irradiated with scanning light emitted from the optical scanner 12, and carries an electrostatic latent image. The developing device 15 develops the electrostatic latent image on the photosensitive drum 13 into a toner image by using the toner supplied from the toner container 10. The sheet P is fed from the sheet feeding cassette 3 to the conveyance path 8 by the sheet feeding device 5, and the toner image on the photosensitive drum 13 is transferred to the sheet P passing through the transfer nip. The fixing device 7 thermally fixes the toner image to the sheet P. Thereafter, the sheet P is discharged to the sheet discharge tray 4. The cleaning device 17 removes the toner remaining on the surface of the photosensitive drum 13.
[Drive Transmission Device] Next, with reference to
As shown in
As shown in
As shown in
<Gear Part> The gear part 32 is a spur gear engaged with the final gear of the gear train 22 (see
<Coupling Part> As shown in
<Biasing member> As shown in
<Retracting Part> The retracting part 35 is made of synthetic resin such as polyacetal, for example, and is formed in a substantially annular shape, through which the coupling part 33 is penetrated. The retracting part 35 into which the coupling part 33 is passed is arranged between the gear part 32 and the main body sheet metal 20. As will be described in detail later, the retracting part 35 is supported around the outer circumferential surface of the coupling part 33, and is rotated around the same axis as the coupling part 33 in a reciprocating manner.
As shown in
The retracting part 35 has an arm portion 37 extending radially outward from the retracting body portion 35A. The arm portion 37 is formed longer in the radial direction than the retracting contact portion 35B. One end of a lever 26 is rotatably connected to the distal end of the arm portion 37. The other end of the lever 26 is rotatably coupled to the cover 25 of the apparatus main body 2 (not shown). The lever 26 connects the cover 25 and the retracting part 35, and the reciprocating rotation of the retracting part 35 is interlocked with the opening and closing of the cover 25.
<Inclined Part> As shown in
The inclined part 40 is formed in a generally conical shape having a contact inclined surface 41 and a non-contact inclined surface 42. More precisely, the inclined part 40 has a shape such that a cone is generally cut in half by the through-hole 24. The contact inclined surface 41 and the non-contact inclined surface 42 are generally inclined planes, and are connected by a curved surface 43 to constitute the inclined part 40. The contact inclined surface 41 and the non-contact inclined surface 42 are inclined so as to be close to each other as they are away from the photosensitive drum 13, and a joint portion (top portion 40T of the inclined part 40) between the contact inclined surface 41 and the non-contact inclined surface 42 is rounded in a substantially hemispherical shape.
As will be described later in detail, when the retracting part 35 is rotated in a reciprocating manner, the retracting contact portion 35B is in contact with the inclined part 40 of the main body sheet metal 20. The contact inclined surface 41 is a surface with which the retracting part 35 (retracting contact portion 35B) is in contact, and the non-contact inclined surface 42 is a surface with which the retracting part 35 (retracting contact portion 35B) is not in contact. The contact inclined surface 41 is inclined gentler than the non-contact inclined surface 42. As shown in
[Function of Drive Transmission Device] With reference to
In the initial state, the drum unit 11 is inserted along the guide rail 23 to the attachment position, and the cover 25 of the apparatus main body 2 is closed (see
When the drum unit 11 is replaced, the drive transmission device 30 (coupling part 33) is separated (uncoupled) from the photosensitive drum 13 (drum coupling 13A). Specifically, when the operator opens the closed cover 25, the rotational force in the opening direction of the cover 25 is transmitted to the retracting part 35 via the lever 26. As shown in
When the drum unit 11 is returned to the initial state after the replacement, the drive transmission device 30 (coupling part 33) is connected to the photosensitive drum 13 (drum coupling 13A). Specifically, when the operator inserts the drum unit 11 into the attachment position along the guide rail 23 and closes the opened cover 25, the rotational force in the closing direction of the cover 25 is transmitted to the retracting part 35 via the lever 26. As shown in
In the drive transmission device 30 according to the present embodiment described above, the two inclined parts 40 are formed by deforming a part of the main body sheet metal 20 (metal plate) so as to protrude in the direction away from the photosensitive drum 13 (drive transmitted portion). If, as shown in
In the drive transmission device 30 according to the present embodiment, the two retracting contact portions 35B of the retracting part 35 protrude radially outward from the retracting body portion 35A, and are in contact with the two inclined parts 40 formed across the through-hole 24. According to this configuration, the coupling part 33 can be substantially moved in parallel along the axial direction (the left-and-right direction). As a result, since a posture of the coupling part 33 is stabilized, the photosensitive drum 13 can be coupled and decoupled to the photosensitive drum 13 properly.
Further, according to the drive transmission device 30 according to the present embodiment, since the inclined part 40 is formed in a mountain shape having the contact inclined surface 41 and the non-contact inclined surface 42, a rigidity (mechanical strength) of the inclined part 40 can be improved compared with the case where the inclined part 40 is formed only by the contact inclined surface 41. Thus, the retracting part 35 riding on the inclined part 40 can be firmly supported. Since the non-contact inclined surface 42 has a steeper slope than the contact inclined surface 41, the inclined part 40 can be formed smaller than when the non-contact inclined surface 42 has the same slope as the contact inclined surface 41. Thus, since a space around the inclined part 40 can be secured widely, interference of the arm portion 37 and the lever 26 with the inclined part 40 can be suppressed, and a smooth rotation of the retracting part 35 can be ensured.
In the drive transmission device 30 according to the present embodiment, the retracting part 35 of the drive transmission device 30 is connected to the cover 25 of the apparatus main body 2 via the lever 26. According to this configuration, the opening and closing of the cover 25 can be interlocked with the reciprocating rotation of the retracting part 35. Thus, the coupling part 33 can be automatically decoupled to the photosensitive drum 13 by opening the cover 25, and the coupling part 33 can be automatically coupled to the photosensitive drum 13 by closing the cover 25.
In the drive transmission device 30 according to the present embodiment, the gear part 32 and the coupling part 33 are integrally molded, but the separately formed gear part 32 and coupling part 33 may be coupled and integrated (not shown).
Further, in the drive transmission device 30 according to the present embodiment, the contact inclined surface 41 of the inclined part 40 has a gentler slope than the non-contact inclined surface 42, but the contact inclined surface 41 and the non-contact inclined surface 42 may have the same slope (not shown). Further, the non-contact inclined surface 42 may be a plane perpendicular to the main body sheet metal 20, and only the contact inclined surface 41 may be an inclined plane (not shown).
In the drive transmission device 30 according to the present embodiment, the inclined part 40 is formed in a substantially conical shape (mountain shape), but the present disclosure is not limited thereto. For example, a pair of cuts (not shown) may be formed in parallel on the main body sheet metal 20, and a substantially V-shaped (or substantially A-shaped) inclined part (not shown) may be formed by extruding between the pair of cuts. In this case, the contact inclined surface 41 may have a gentler slope than the non-contact inclined surface 42, or the contact inclined surface 41 and the non-contact inclined surface 42 may have the same slope (not shown). In addition, a substantially U-shaped cut (not shown) may be formed in the main body sheet metal 20, and an area surrounded by the cut may be extruded to form the inclined part (not shown) having only the contact inclined surface 41 while omitting the non-contact inclined surface 42.
In the drive transmission device 30 according to the present embodiment, the two inclined parts 40 are formed across the through-hole 24, but the present disclosure is not limited thereto. For example, three or more inclined parts 40 may be formed so as to surround the through-hole 24 (not shown). Further, a number and a position of the retracting contact portion 35B of the retracting part 35 may be adjusted in accordance with a number and a position of the inclined parts 40 (not shown).
Further, in the drive transmission device 30 according to the present embodiment, the retracting part 35 includes the retracting body portion 35A and two retracting contact portions 35B, but the present disclosure is not limited thereto, and for example, the retracting part 35 may be formed in an elliptical shape, and the long diameter portions may be used as the two retracting contact portions (not shown).
Further, although the drive transmission device 30 according to the present embodiment transmits a driving force to the photosensitive drum 13 as an example of the drive transmitted portion, the present disclosure is not limited thereto. The drive transmission device 30 may transmit a driving force to a drive transmitted portion rotating around an axis, such as a stirring member of the toner container 10 or a developing roller of the developing device 15 (both not shown).
In the image forming apparatus 1 according to the present embodiment, the retracting part 35 is connected to the cover 25 via the lever 26, but the present disclosure is not limited thereto. For example, the lever 26 may not be connected to the cover 25, and an operator may operate the lever 26 to rotate the retracting part 35 in a reciprocating manner after opening the cover 25 (not shown). Another image forming apparatus may omit the lever 26 and include a sensor for detecting the opening and closing of the cover 25 and a motor for rotating the retracting part 35 in a reciprocating manner based on the detection result of the sensor (not shown).
In the description of the present embodiment, as an example, the image forming apparatus 1 is a printer, but it is not limited thereto, and may be, for example, a copying machine or a facsimile machine.
It should be noted that the description of the above-described embodiment shows one aspect of the drive transmission apparatus and the image forming apparatus according to the present disclosure, and the technical range of the present disclosure is not limited to the above-described embodiment. The present disclosure may be varied, replaced, and modified without departing from the spirit of the technical thought, and the scope of the claims includes all embodiments which may be included within the scope of the technical thought.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2024-007186 | Jan 2024 | JP | national |
