JP3266442B2 - Drum shaft coupling structure of image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum shaft coupling structure of an image forming apparatus, and more particularly to a drum shaft coupling structure of an image forming apparatus in which a flywheel is connected to a drum shaft to suppress a rotational vibration of a photosensitive drum. .

[0002]

2. Description of the Related Art In a conventional copying machine, in particular, a digital copying machine, unevenness occurs in a formed image due to slight rotation vibration (rotation unevenness) of a photosensitive drum. for that reason,
By fixing a flywheel as an inertial body to the shaft of the photoconductor drum, rotational vibration of the photoconductor drum is suppressed.

In a conventional copying machine having such a flywheel, in order to take out the photosensitive drum outside the machine, the flywheel is removed from the drum shaft, and the drum body is taken out together with the drum shaft. This task is difficult due to the heavy weight of the flywheel. SUMMARY OF THE INVENTION It is an object of the present invention to replace a photosensitive drum with a simple operation in an image forming apparatus in which a flywheel is connected to a drum shaft in order to suppress rotational vibration of the photosensitive drum.

[0004]

According to one aspect of the present invention , there is provided a drum shaft coupling structure for an image forming apparatus, wherein a flywheel is connected to a drum shaft to suppress rotational vibration of a photosensitive drum. The shaft coupling structure includes a first joint and a second joint. The first joint is provided at one end of the drum shaft. The second joint is axially movable between a first position coupled to the first joint and a second position disengaged from the first joint, and the flywheel is mounted thereon. A center hole is formed in the first joint, and the center hole is formed.
Is extended axially at two locations facing radially
An inclined surface that gradually narrows from the tip side to the back
Groove is formed. In addition, the second joint part is the first joint part.
A shaft that can be inserted into the center hole of the joint and a shaft that faces the shaft in the radial direction
A pin which is provided at two places and which can be fitted into the groove of the first joint portion;
have. An image forming apparatus according to another aspect of the present invention
The drum shaft coupling structure suppresses the rotational vibration of the photosensitive drum.
Image formation with flywheel connected to drum shaft
It is a drum shaft coupling structure of the device, and a first coupling portion and a second coupling portion.
A hand portion and an image forming apparatus main body frame are provided. No.
One joint is provided at one end of the drum shaft. 2nd joint
The part has been uncoupled from the first position coupled to the first joint part
The flywheel is movable in the axial direction between the second position and the second position.
Is attached. The frame of the main body of the image forming apparatus
The ram shaft and the first joint are supported. Then, the image forming apparatus
The drum shaft and the first joint are image-formed on the
Notch is formed on the front side of
Have been.

[0005] It is preferable to further include a locking mechanism capable of locking the second joint portion at the second position. The second joint portion is rotatable, and the locking mechanism includes a protrusion extending radially from the second joint portion, and a stopper member having a hole through which the second joint portion and the protrusion can pass. Is preferred.

[0006] It is preferable that a biasing member for biasing the second joint portion against the first joint portion is further provided.

[0007]

In the drum joint structure of the image forming apparatus according to one aspect of the present invention , the second joint is connected to the first joint at the first position during the operation of the image forming apparatus. At this time, when the photosensitive drum rotates, the flywheel rotates, and the rotational vibration of the photosensitive drum is suppressed.

When removing the photosensitive drum, the second joint is moved to the second position. Thereby, the photosensitive drum and the drum shaft can be pulled out from the image forming apparatus. Here, since the coupling with the first joint can be released by moving the second joint in the axial direction, the photosensitive drum can be easily removed. Also, when attaching the photoconductor drum
, The opposite of the removal work, but at this time,
The width of the groove of the center hole of the first joint part becomes narrower as it goes deeper.
So that the pin of the second joint is smooth.
Into the groove. Image form according to another aspect of the present invention
The drum shaft coupling structure of
When pulling out the ram shaft, the
The photoreceptor drum is suspended from the drum axis by the
Work can be done easily because it can be pulled out straight forward.
Becomes easier.

In the case where the locking mechanism is composed of the projecting portion of the second joint and the stopper member, the second joint is connected to the first joint.
After being separated from the joint and passing through the hole of the stopper member, it is rotated by a predetermined angle. Then, the projecting portion of the second joint portion comes into contact with the stopper member and is locked. Here, the second joint portion can be easily locked at the second position simply by moving and rotating the second joint portion in the axial direction.

[0010] In the case where a biasing member is further provided, the second
The joint between the first joint and the second joint is strengthened by urging the joint against the first joint. As a result, torque fluctuation between the two is reduced.

[0011]

1 shows a digital copying machine employing an embodiment of the present invention. In FIG. 1, a document table 2 is fixed on an upper surface of a copying machine body 1, and a document holder 3 is opened and closed on the document table 2. It is provided freely. Inside the copying machine body 1,
A scanning unit 4 for reading a document is provided on the upper part. The scanning unit 4 includes a light source, a mirror, a lens unit,
It is composed of a photoelectric conversion element and the like. A laser unit 5 having a laser light generator and the like is provided on the side of the scanning unit 4. Further, an image forming unit 6 for forming a toner image based on image information of a document is provided at a central portion of the copying machine main body 1. The image forming section 6 includes a photosensitive drum 21, a charging device, a developing device, and the like. A polygon mirror 7 for irradiating the photosensitive drum 21 with laser light emitted from the laser unit 5 is provided between the image forming unit 6 and the laser unit 5.

A paper feed unit 10 is provided below the copying machine main body 1. The paper supply unit 10 includes three paper supply cassettes 11, 12, and 13 arranged vertically, and a large paper supply cassette 14 disposed beside the paper supply cassettes 11 to 13.
And a paper feeder 15 for transporting the paper stored in each of the cassettes 11 to 14 to the image forming unit 6. On the downstream side of the image forming unit 6 for conveying the sheet, a sheet discharging and conveying device 16 for conveying the sheet to the left side of the apparatus, a fixing device 17 for fixing the toner image on the sheet, and discharging of the fixed sheet. And a discharge tray 19 for receiving the discharged paper.

Further, although not shown, the copier main body 1 is provided with a control unit composed of a microcomputer including a CPU, a RAM, a ROM and the like. next,
The photosensitive drum 21 will be described in detail with reference to FIGS. A cylindrical first joint member 33 is fixed to one end of the drum shaft 21 a of the photosensitive drum 21 by a rivet 34. The first joint member 33 has a flange 3 on the distal end side.
3a. Further, a center hole 33b is formed in the first joint member 33, and two axially extending grooves 33c are formed in the center hole 33b so as to oppose each other in the radial direction. The groove 33c has an inclined surface that gradually narrows from the front end toward the back. A ball bearing 35 is fixed around the first joint member 33. The ball bearing 35 is fitted in a hole of the main body frame 32.
As described above, the first joint member 33 is connected to the ball bearing 35.
And is supported by the main body frame 32. The photosensitive drum 21 can be slid from the main body frame 32 to the front of the apparatus. A mechanism for transmitting torque to the drum shaft 21a is provided at the other end of the photosensitive drum 21.

The drum bearing structure 31 is a structure for connecting / disconnecting the flywheel 46 to / from the drum shaft 21a of the photosensitive drum 21. The drum bearing structure 31 mainly includes
It comprises a mounting member 41, a flywheel shaft 42, a coil spring 43, a stopper 44, and a hub 45. The mounting member 41 is fixed outside the main body frame 32. The mounting member 41 has a hole 41a through which the flywheel shaft 42 penetrates.
Are bush bearings 56 arranged in the holes 41a,
It is supported by 57.

First joint member 33 of flywheel shaft 42
At the front end side facing the front end, coupling pins 42a provided at two locations facing each other in the radial direction protrude. Coupling pin 42a
Is fitted in the groove 33c of the first joint member 33, as shown in FIG. A retaining ring 51 is further fixed to the flywheel shaft 42. Coil spring 43
Has one end supported by the mounting member 41 and the other end
To the first joint member 33 side. Thus, the first joint member 33 and the flywheel shaft 42 are firmly connected.

A hub 4 is provided at the rear end of the flywheel shaft 42.
5 are provided. The hub 45 has a flywheel 46
Is attached. A stopper 44 is fixed to the flywheel 46 side of the mounting member 41. The stopper 44 is a plate-like member having a hole 44a corresponding to the shape of the flywheel shaft 42 and the release pin 52.

Next, the operation will be described. When the photosensitive drum 21 rotates in the coupled state shown in FIG. 3, the flywheel 46 rotates together via the flywheel shaft 42. At this time, the rotational vibration of the photosensitive drum 21 is suppressed by the inertia of the flywheel 46. As a result, the deterioration of the image quality due to the rotational vibration of the image formed on the paper is reduced. At this time, since the flywheel shaft 42 is urged by the coil spring 43 toward the first joint member 33, the connection between the two is strengthened. As a result, torque fluctuation between the two is reduced.

To remove the photosensitive drum 21, the operator moves the flywheel shaft 42 to the right in FIG. Then, the release pin 52 is passed through the hole 44a of the stopper 44, and the flywheel shaft 42 is slightly rotated. Then, the release pin 52 of the flywheel shaft 42 is locked by the stopper 44 (FIG. 3). Thus, the first joint member 3
In a state where the connection between the flywheel shaft 3 and the flywheel shaft 42 is released, the photosensitive drum 21 is pulled out together with the first joint member 33 and the ball bearing 35 toward the front side of the copying machine main body 1 (in the direction of the arrow in FIG. 3). In this work, the photosensitive drum 2
1 can be pulled out in the direction perpendicular to the drum shaft 21a, so that a large work space is not required. In addition, in this work,
Since there is no need to remove the flywheel 46,
Easy operation and high safety.

When the photosensitive drum 21 is mounted, the operation opposite to the above-mentioned operation is performed. At this time, the groove 33
Since c is inclined so as to become narrower toward the back, the coupling pin 42a smoothly enters the groove 33c. In the above-described embodiment, an example in which the drum is attached and detached in a direction perpendicular to the drum axis has been described. However, the present invention is not limited to this.
It is also possible to apply to a form in which the drum is attached and detached in the direction of the drum shaft.

[0020]

According to the drum shaft coupling structure of the image forming apparatus according to one aspect of the present invention, the coupling with the first coupling portion is released by moving the second coupling portion in the axial direction.
The photosensitive drum can be easily removed. Also, the photosensitive drum
When attaching the second joint to the groove in the center hole of the first joint
The hand pins smoothly enter and work becomes easier. Book
Drum shaft coupling structure of image forming apparatus according to another aspect of the invention
In the notch formed in the frame of the image forming device,
Therefore, the photosensitive drum is moved forward in the direction perpendicular to the drum axis.
Since the drawer can be pulled out as it is, the work becomes easier. In the case where a locking mechanism is further provided, the second joint portion is securely connected to the first joint.
It can be separated from the joint.

In the case where the locking mechanism comprises the projecting portion of the second joint portion and the stopper member, the second joint portion is moved to the second joint portion by a simple operation consisting only of the axial movement and rotation of the second joint portion. Can be locked in position. When the urging member is further provided, the torque fluctuation between the first joint and the second joint is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a digital copying machine employing one embodiment of the present invention.

FIG. 2 is a schematic partial cross-sectional view of a drum bearing structure as one embodiment of the present invention.

FIG. 3 is a schematic partial cross-sectional view of a drum bearing structure as one embodiment of the present invention.

FIG. 4 is a schematic perspective view of a drum bearing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier main body 21 Photoreceptor drum 21a Drum shaft 31 Drum bearing structure 33 First joint member 42 Flywheel shaft 46 Flywheel

──────────────────────────────────────────────────続 き Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 21/00 350 G03G 15/00 550 F16F 15/315

Claims (5)

(57) [Claims] 1. A drum joint structure for an image forming apparatus in which a flywheel is connected to a drum shaft in order to suppress rotational vibration of a photosensitive drum, wherein a first joint portion provided at one end of the drum shaft is provided. the first position in which first attached to the joint portion is movable in the axial direction between the second position releasing the coupling, and a second joint portion in which the flywheel is attached, said first joint A central hole is formed in the portion, and the central hole
Extends axially at two locations facing radially and has a tip
Has an inclined surface that gradually narrows from the side to the back
That the groove is formed, the second joint portion is insertable into a center hole of the first coupling part
And two shafts that are radially opposed to the shaft.
A drum shaft coupling structure for an image forming apparatus , comprising: a pin that can be fitted into a groove of the first coupling portion . 2. A drum shaft coupling structure of an image forming apparatus in which a flywheel is connected to a drum shaft in order to suppress a rotational vibration of a photosensitive drum, wherein a first coupling portion provided at one end of the drum shaft is provided. A second joint part to which the flywheel is attached, which is axially movable between a first position coupled to the first joint part and a second position disengaged from the coupling, the drum shaft and the first joint part; Image forming device book supporting joints
A body frame, wherein the image forming apparatus main body frame includes the drum shaft and
The first joint can be pulled out to the front side of the image forming apparatus.
A drum joint structure of an image forming apparatus , wherein a notch is formed . Wherein the second drum shaft joint structure of the image forming apparatus according to claim 1 or 2 further comprising a lockable locking mechanism joint portion at the second position. 4. The second joint portion is rotatable, and the locking mechanism includes a protrusion extending radially from the second joint portion, and a hole through which the second joint portion and the protrusion can pass. And a stopper member having:
4. The drum shaft coupling structure of the image forming apparatus according to 3 . 5. A drum shaft joint structure of the image forming apparatus according to still claim 1-4 comprising a biasing member for biasing said second coupling portion with respect to the first joint portion.