JPH0727184A - Drive transmission device - Google Patents

Abstract

PURPOSE:To reduce size and a cost by a method wherein even when a gear itself is not moved, a process unit is smoothly mounted and parts not related directly to drive transmission are eliminated. CONSTITUTION:A gear 6 is formed rotatably in the direction of an arrow mark B in a way that a drive transmission device comprises a gear 6; another gear located coaxially with the gear 6 and engaged so as to have a constant backlash in a rotation direction; and a spring through the force of which a backlash between the gears is energized in one-way. Since the gear 6 is rotated in the direction of the arrow mark B even when the gears 2 and 6 are interfered with each other when a process unit 1 is mounted, the process unit 1 is smoothly mounted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transmission device for an image forming apparatus such as a printer, a copier, a facsimile, etc., and more particularly, a drive transmission portion for a unit detachable from the image forming apparatus main body and the image forming apparatus main body. In regard to the drive transmission device.

[0002]

2. Description of the Related Art Conventionally, a drive transmission device in an image forming apparatus has been remarkably inexpensive and compact.

A conventional drive transmission device will be described below. 4A and 4B are schematic configuration diagrams of an image forming apparatus including a conventional drive transmission device, FIG. 5 is a schematic configuration diagram of a conventional drive transmission device, and FIG. 6 is a perspective view of the conventional drive transmission device. Is.

In FIGS. 4A and 4B, 18 is a lower chassis, 19 is an upper chassis rotatably supported by the lower chassis 18, 20 is a sheet material, and 21 is a sheet material 20.
A paper feed cassette filled with paper, 22 a paper feed roller for feeding the sheet material 20 in the paper feed cassette 21, 23 a conveyance roller for conveying the fed sheet material 20 to an image transfer portion, 2
Reference numeral 4 denotes an image carrier that forms an image on the outer peripheral surface thereof and transfers it to the sheet material 20, 25 is a laser scanning unit that is fixed to the upper chassis 19 and scans the laser light on the image carrier 24 to form a latent image, 1 Is a process unit in which an apparatus for performing an image forming process including the image carrier 24 is integrated,
Reference numeral 2 denotes a gear that is fixed to the image carrier 24 and transmits a driving force from a driving device such as a motor in the lower chassis 18 into the process unit 1, and 26 transfers an image on the image carrier 24 onto the sheet material 20. A transfer device, 27 is a fixing device for fixing the image on the sheet material 20 by an internal heat source and two rollers,
8 is a discharge roller for discharging the fixed sheet material 20, 2
9 is a tray on which the discharged sheet materials 20 are stacked.

Next, in FIGS. 5 and 6, 3 is a support shaft for supporting the gear 2, 4 is a side plate fixed to the lower chassis 18 shown in FIG. 4, 5 is a side plate 4, and the support shaft 3 is fitted therein. Accordingly, the process unit 1 is positioned with respect to the lower chassis 18, and the gears 30, 31, 32 are gears to which the driving force from the driving device is first transmitted to the gears 32, 3 and 3.
It is sequentially transmitted to 0. 33 and 37 are shafts fixed to the side plate 4 and rotatably supporting the gears 31 and 32, and 34 is rotatably supported by the shaft 33, and the gears 30 and 3 are rotatably supported.
1 is a holder which supports 1 so that the center-to-center distance is constant, 35 is a shaft which is fixed to the holder 34 and rotatably supports the gear 30, and 36 is one end which is fixed to the side plate 4 and which attaches the holder 34 in the arrow G direction. It is a spring that is urging.

The operation of the drive transmission device configured as described above will be described below. First, in FIG. 4B, the process unit 1 is a consumable item and needs to be frequently replaced by the user. When the upper chassis 19 is opened, the process unit 1 can be easily attached and detached.

When the process unit 1 is mounted, the support shaft 3 is inserted in the direction of arrow A as shown in FIG. At this time, since the gear 30 is biased by the spring 36 in the direction of arrow G, it does not interfere with the gear 2. Therefore, the process unit 1 is mounted smoothly. When the drive device operates, the gear 31 rotates, and the gear 30 moves in the direction of the arrow H to be coupled with the gear 2 because the force of the spring 36 is set smaller than the torque due to this torque. Gear 30 to gear 2
When the driving force is transmitted to the gear 2 due to the reaction force between the gears,
Is applied to the gear 30, and a force in the direction of arrow E is applied to the gear 30, so that the process unit 1 is urged in the direction not to be disengaged from the groove 5,
The gear 30 is further urged in the direction of arrow H, that is, in the direction in which it meshes with the gear 2. When the drive device stops, the gear 30 moves in the direction of the arrow G by the spring 36 and the interference with the gear 2 disappears, so that the process unit 1 can be taken out smoothly. Therefore, since the process unit 1 can be coupled and retracted with the gear unit 30 and the process unit 1 can be fixed by operating and stopping the drive unit, the process unit 1 does not require a special mechanism.
It is possible to smoothly attach and detach and fix.

[0008]

However, in the above-mentioned conventional structure, since the gear 30 moves, a space for it is required, and the holder 3 which is not directly related to drive transmission.
Since there are 4 parts and the like, there is a problem that the cost becomes high.

[0009]

In order to solve the above-mentioned problems, the present invention transmits a driving force from a driving means provided on the frame body to the unit side which is detachable from the frame body into the unit. The first gear, the second gear that is provided on the frame side and meshes with the first gear, and has a certain amount of play in the rotation direction of the second gear, and transmits the driving force from the driving means to the second gear. And a resilient member that biases the third gear in a specific rotation direction.

[0010]

With the above structure, the present invention allows the rotation of the third gear that transmits the driving force to the unit to be free when the unit is attached to or detached from the frame.

[0011]

An embodiment of the present invention will be described with reference to the drawings. 1 is a schematic configuration diagram of a drive transmission device according to an embodiment of the present invention, FIG. 2 is a perspective view of the drive transmission device according to an embodiment of the present invention, and FIGS. 3 (a), 3 (b), and 3 (c) are main drawings. In the detailed drawings of the main parts of the drive transmission device according to the embodiment of the invention, the same components as those of the conventional drive transmission device shown in FIGS.

In FIG. 1, 6 is a gear, and 7 is a shaft fixed to the side plate 4 to rotatably support the gear 6. Figure 2
In the figure, 8 and 9 are gears, and the driving force from a driving device such as a motor is first transmitted to the gear 9 and then sequentially transmitted to the gear 6. 10 is a lower chassis 18 shown in FIG.
Is a support plate that is fixed to and supports the end of the shaft 7.
In FIG. 3, 11 is a spring and 12 and 13 are ends of the spring 11, which are bent. Reference numeral 14 is a protrusion formed on the gear 6, and 15 is a groove formed on the gear 6, which is the end portion 1 of the spring 11.
2 is inserted. Reference numeral 16 is a protrusion formed on the gear 8 and is engaged with the protrusion 14 of the gear 6. Reference numeral 17 denotes a groove formed in the gear 8 into which the end portion 13 of the spring 11 is inserted.

The operation of the drive transmission device according to the embodiment of the present invention constructed as above will be described below.

First, as shown in FIG. 3C, the protrusion 14 of the gear 6 and the protrusion 16 of the gear 8 are engaged with each other with a certain amount of play in the rotation direction of the gears 6, 8. Since the spring 11 is formed so as to bias the protrusion 14 in the arrow F direction, the gear 6 can rotate in the arrow B direction when no load is applied.

Next, in FIG. 1, when the process unit 1 is mounted, the support shaft 3 is inserted in the direction of arrow A. At this time, the gear 2 and the gear 6 interfere with each other, but since the gear 6 can rotate in the direction of the arrow B as described with reference to FIG. 3C, the process unit 1 can be mounted smoothly. When the drive device works here, the gear 6 rotates. When the driving force is transmitted from the gear 6 to the gear 2, a reaction force between the gears applies a force in the direction of the arrow D to the gear 2 and a force to the gear 6 in the direction of the arrow E, so that the process unit 1 does not come out of the groove 5. Be energized.

When taking out the process unit 1, the gear 2 is used.
And the gear 6 mesh with each other, the following operation is performed. Since the gear 6 has a large reduction ratio from the drive unit and is also coupled to the elements of other image forming apparatuses, a large torque is required to rotate it. However, since the gear 2 is connected only to the elements in the process unit 1 and has a small gear ratio, a relatively small torque is required to rotate the gear. Therefore, when the process unit 1 is taken out, an extra force for rotating the gear 2 is required more than when mounting the process unit 1. However, when the process unit 1 is mounted, the process unit 1 needs to be accurately positioned, and smooth mounting property is required to prevent the mounting failure, but a relatively strong force is not a problem when taking it out.

As described above, according to this embodiment, the gear 6 for transmitting the drive to the process unit 1 and another gear 6 coaxially connected to the process unit 1 so as to have a certain play in the rotational direction. Since the gear 8 and the spring 11 that biases the play between the gears 6 and 8 in a certain direction are provided, the gear 6 does not move when the process unit 1 is attached or detached, so that the apparatus can be downsized. Since it is possible to reduce parts such as a holder that supports the gear 6 that are not directly related to drive transmission, it is possible to achieve low cost.

[0018]

According to the present invention, the first gear is provided on the unit side which is detachable from the frame and transmits the driving force from the drive means provided on the frame into the unit, and the first gear provided on the frame side. A second gear that meshes with the first gear, a third gear that has a certain amount of play in the rotation direction of the second gear and that transmits the driving force from the driving means to the second gear, and a third gear. By providing an elastic member that biases in a specific rotation direction, the rotation of the third gear that transmits the driving force to the unit can be made free when the unit is attached to or detached from the frame, and when the unit is attached or detached. Since the third gear itself that transmits the driving force to the unit does not move, the device can be downsized, and the cost can be reduced by reducing the number of parts.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a drive transmission device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a drive transmission device according to an embodiment of the present invention.

FIG. 3 is a detailed view of main components of the drive transmission device according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an image forming apparatus including a conventional drive transmission device.

FIG. 5 is a schematic configuration diagram of a conventional drive transmission device.

FIG. 6 is a perspective view of a conventional drive transmission device.

[Explanation of symbols]

 1 Process Unit 2, 6, 8 Gear 3 Support Shaft 4 Side Plate 5 Groove 11 Spring 14 and 16 Protrusion

Claims (2)

[Claims] 1. A drive unit, a frame body provided with the drive unit, a unit having a member driven by the drive unit and detachable from the frame body, and the drive unit provided on the unit side. A first gear that transmits the driving force from the inside of the unit, a second gear that is provided on the frame side and that meshes with the first gear, and a certain amount of play in the rotation direction of the second gear. Drive transmission comprising a third gear for transmitting the drive force from the drive means to the second gear and an elastic member for urging the third gear in a specific rotation direction. apparatus. 2. The drive transmission according to claim 1, wherein the centers of rotation of the second gear and the third gear are coaxial with each other, and the elastic member is a torsion coil spring concentric with the shaft. apparatus.