JPH10148984A - Driving transmission mechanism and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the backlash of the gear on a paper feed unit side and the gear on an image forming device body side or both gear and to obviate the generation of large noises and vibrations by facilitating the miniaturization of an image forming device body and averting the interference of the tips of both gears at mounting the paper feed unit to the image forming device body. SOLUTION: A driving gear 100C as a driving transmission element is mounted on the image forming device body side. This driving gear 100C is a fully toothed gear having teeth over the entire periphery. A driven gear 200C which is the driving transmission element is installed to the paper feed unit side attachably and detachably mounted at the image forming device body. This driven gear 200C is a tooth lacked gear from which the plural tooth at one point of the outer periphery are removed. The drive of a main motor is transmitted via the driving gear 100C to the driven gear 200C fixed onto a paper feed roller shaft 201C. The tooth lacked part 202 of the driven gear 200C faces the driving gear 100C at the point of the time the paper feed unit is mounted at the prescribed position of the image forming device body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transmission mechanism for transmitting rotational drive from a machine body provided with a drive source to a machine component unit detachably attached to the machine body.

[0002]

2. Description of the Related Art In the case of an image forming apparatus such as a copying machine, a printer, a facsimile, etc., a mechanical component unit in which a plurality of components are unitized is incorporated in an image forming apparatus main body (machine main body) in a detachable state. The reason for this is to facilitate, for example, jam clearance, component replacement, maintenance, and the like. A typical example of such a mechanical component unit is a paper feed unit including a paper feed roller.

Some mechanical component units detachably attached to the main body of the image forming apparatus have their own drive sources. Rotation drive from a motor or the like) is transmitted via a drive transmission mechanism.

FIG. 9 shows a configuration of a drive transmission mechanism for a conventional paper feed unit (conventional example 1).

FIG. 9 shows a state in which a sheet feeding unit (not shown) is set at a predetermined position of an image forming apparatus main body (not shown). In this case, the paper feed unit is moved in the direction of arrow X. When the sheet feeding unit moves to a predetermined position of the image forming apparatus main body, the driven gear 200A provided on the sheet feeding unit side meshes with the driving gear 100A provided on the image forming apparatus main body side. Here, the driving gear 100A on the image forming apparatus main body side and the driven gear 20
In order to facilitate the meshing of 0A, the backlash is set larger than that of the normal gear.

The drive from a main motor (not shown) provided in the image forming apparatus main body is transmitted to the drive gear 100A. A driven gear 200A to which driving is transmitted from the driving gear 100A is fixed on a sheet feeding roller shaft 201A.

When the paper feeding unit is detached from the image forming apparatus main body due to jam clearance or replacement of a worn paper feeding roller, the paper feeding unit is unlocked, and then the paper feeding unit is mounted in the opposite direction. Move to By doing so, the engagement between the driving gear 100A on the image forming apparatus main body side and the driven gear 200A on the paper feeding unit side is also released.

FIG. 10 shows the configuration of another conventional drive transmission mechanism for a paper feed unit (Prior Art 2).

FIG. 10 shows a state in which a sheet feeding unit (not shown) is set at a predetermined position of an image forming apparatus main body (not shown). In this case, the paper feed unit is moved in the direction of arrow X. When the sheet feeding unit moves to a predetermined position of the image forming apparatus main body, the driven gear 200B provided on the sheet feeding unit side meshes with the driving gear 100B provided on the image forming apparatus main body side via the swing gear 101. .

The oscillating gear 101 is rotatably mounted on the tip side of an oscillating arm 103 rotatably mounted on a gear shaft 102A of a driving gear 100B, and meshes with the driving gear 100B. The swing arm 103 is urged clockwise by an urging force of a torsion spring 104 mounted on the gear shaft 102A.

Before the paper supply unit is attached to the image forming apparatus main body, the swing arm 103 is at a position slightly rotated clockwise from the position shown in FIG. 10 (the meshing position of the gears 101 and 200B). However, when the sheet feeding unit is moved in the direction of arrow X, the driven gear 200B pushes up the swing gear 101, so that the swing arm 103
Rotates counterclockwise to the position of FIG. 10 against the biasing force of the torsion spring 104. Then, the driven gear 200B set at a predetermined position and the swing gear 101 urged in the clockwise direction mesh with a normal gear meshing backlash.

As described above, if the drive gear 100B of the image forming apparatus main body and the driven gear 200B of the paper feed unit are engaged with each other via the swing gear 101, the drive gear 100B and the driven gear 200B are easily engaged with each other. Become.

A drive from a main motor (not shown) provided in the image forming apparatus main body is transmitted to the drive gear 100B. In addition, the driving gear 1
The driven gear 100B to which the drive is transmitted from 00B is fixed on the feed roller shaft 201.

When the paper feeding unit is detached from the image forming apparatus main body due to jam clearance or replacement of a worn paper feeding roller, the paper feeding unit is unlocked, and then the paper feeding unit is mounted in the opposite direction. Move to By doing so, the engagement between the driving gear 100B (oscillating gear 101) on the image forming apparatus main body side and the driven gear 200B on the paper feeding unit side is also released.

[0015]

However, when the drive transmission mechanisms of the first and second conventional examples are adopted, there are the following problems.

That is, in the case of the drive transmission mechanism of the conventional example 1, the meshing drive gear 100A and the driven gear 200A
Since the backlash of A is large, large noise and vibration are generated. Further, the drive transmission efficiency also decreases. Further, when both the load torque on the drive gear 100A side and the load torque on the driven gear 200A side are large, both gears 100A, 2A
If the tooth tips come into contact with each other when the 00A is engaged, the engagement becomes difficult.

Further, in the case of the drive transmission mechanism of the conventional example 2, the swing gear 10B is provided between the drive gear 100B and the driven gear 200B.
1 intervenes, the driving gear 100B and the driven gear 200B
The distance L between axes of B becomes large, which makes it difficult to reduce the size of the image forming apparatus main body (machine main body). When the driving direction of the driven gear 200B is reversed due to the interposition of the swing gear 101, the driving gear 10
An idler gear must be interposed between the driven gear 100B and the driven gear 200B.
Is further increased.

Therefore, the present invention has been made in view of the above-described circumstances, and (1) the distance between the axes of the machine body side gear and the machine part unit side gear does not increase; (2) the machine body side It is an object of the present invention to provide a drive transmission mechanism that has advantages such as easy engagement of a gear and a gear on a mechanical component unit side, (3) no generation of loud noise or vibration, and (4) reduction of drive transmission efficiency.

[0019]

According to the present invention, a first gear installed on a machine body side and a mechanical part unit detachably mounted on the machine body are provided. A second gear meshing with the first gear, and transmitting a drive of a drive source provided in the machine main body to the machine component unit via the first gear and the second gear; Related to a drive transmission mechanism.

According to the present invention, in order to achieve the above object, one of the first gear and the second gear is a full-tooth gear having teeth all around, and the other is a full-tooth gear. 1
A toothless gear with a plurality of teeth removed therefrom, and rotation stop means for stopping the rotation of the toothless gear at a position where the toothless portion faces the all-tooth gear.

In general, it is also necessary to provide an urging means for urging the toothless gear, which has been stopped by the rotation stopping means, in the rotational direction.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 shows the overall structure of an image forming apparatus (electrophotographic copying machine) to which the present invention is applied. 2, 3 and 5 show the configuration of the drive transmission mechanism of the present invention.

First, the overall configuration of the image forming apparatus shown in FIG. 1 will be described.

When a copy button (not shown) is pressed, the scanning unit 300 moves in the direction of arrow a,
The image of a document (not shown) set on the original 01 is read.

That is, the scanning unit 300 moves to a predetermined position in the direction of arrow a while irradiating the original with the light of the illumination lamp 302. When the scanning unit 300 moves to the predetermined position, the scanning unit 300 moves in the direction of arrow b with the illumination lamp 302 turned off and returns to the home position.

As the scanning unit 300 moves in the direction of the arrow a, the light (light image) L reflected on the original surface is reflected by the reflection mirror 303 of the scanning unit 300 as shown by an imaginary line.
And the reflection mirror 30 of the first reflection unit 304
The light is reflected at 5, 306, passes through the lens unit 307, is reflected by the reflection mirrors 309, 310 of the second reflection unit 308, is reflected by the final reflection mirror 311 and is on the photosensitive drum 312 rotating clockwise. Projected to

As a result, an electrostatic latent image is sequentially formed on the photosensitive drum 312, and the electrostatic latent image is visualized (toner image) by toner supplied from a developing unit (not shown).
Then, the sheet is conveyed to a transfer portion between the photosensitive drum 312 and the transfer roller 313.

While the toner image is formed on the photosensitive drum 312 in this manner, the sheet S as the transfer material is transferred from the sheet feeding cassette 314 or the manual feed tray 315 to the sheet S.
Paper is fed one by one.

The sheets S stacked in the sheet feeding cassette 314 are fed out one by one from the uppermost sheet by a sheet feeding roller 316 which stops one rotation counterclockwise from a position (home position) shown in the figure. Then, the sheet is fed to the registration roller pair 317 in the rotation stopped state.

Sheets (not shown) stacked on the manual feed tray 315 are fed out one by one from the uppermost sheet by a paper feed roller 318 that rotates clockwise until the registration roller pair 317 stops rotating. Sent.

Both the sheet S fed from the sheet feeding cassette 314 and the sheet fed from the manual feed tray 315 are stopped when the leading edge of the sheet strikes the nip of the pair of registration rollers 317 to form a predetermined amount of loop. It is supposed to. By forming this loop, the skew state of the sheet S is corrected, and the sheet S in the correct posture is sent to the transfer unit.

The sheet S whose skew has been corrected is sent to the transfer unit by a pair of registration rollers 317 which start rotating at the timing when the position of the toner image on the photosensitive drum 312 and the leading end of the sheet are adjusted. Then, the toner image on the photosensitive drum 312 is sequentially transferred to the sheet S passing through the transfer section by the transfer roller 313.

The sheet S having passed through the transfer section is transported by the transport belt 3
19 to the fixing device 320. The sheet S is heated and pressurized while passing through the nip of the fixing device 320, and the transferred toner image is fixed on the sheet surface.

The sheet S having passed through the fixing device 320 is discharged onto a discharge tray 322 outside the apparatus by a discharge roller pair 321.

In the case of the present image forming apparatus, all the mechanical components that are rotationally driven (paper feed rollers 316 and 318, registration roller pair 317, photosensitive drum 312, transport belt 319,
Drive from a main motor (drive source) 324 installed in the image forming apparatus main body 323 is transmitted to the fixing device 320 and the discharge roller pair 321.

In the case of the present image forming apparatus, the paper feed unit 325 including the paper feed roller 316 is provided for facilitating jam clearance and replacing the worn paper feed roller 316.
It is detachably attached to the image forming apparatus main body 323. A process cartridge 326 including a photosensitive drum 312 and a developing device (not shown) is also detachably attached to the image forming apparatus main body 323 in order to replenish the developer (toner) and replace process components.

Here, the configuration of the drive transmission mechanism of the present invention shown in FIGS. 2, 3 and 5 will be described. The drive transmission mechanism controls the drive of the main motor 324 by the feed roller 3
Tell 16

FIG. 2 (and FIG. 5) shows the sheet feeding unit 325.
Indicates a state at the time when the image is set at a predetermined position of the image forming apparatus main body 323. In this case, the paper feeding unit 325
Is moved in the arrow X direction.

A drive gear 100C as a drive transmission element is provided on the image forming apparatus main body 323 side. The drive from the main motor 324 is transmitted to the drive gear 100C. The drive gear 100C is a full-tooth gear having teeth all around.

A driven gear 200C, which is a drive transmission element, is provided on the sheet feeding unit 325 side. The driven gear 200C is fixed on the feed roller shaft 201C. The driven gear 200C is a toothless gear obtained by removing a plurality of teeth from one location on the outer circumference.

The paper feeding unit 325 is used for the image forming apparatus main body 3.
23, the image forming apparatus main body 3
The driving gear 100C on the 23 side and the driven gear 200C on the paper feeding unit 325 have a positional relationship capable of meshing with each other, but when the paper feeding unit 325 is set at a predetermined position of the image forming apparatus main body 323, the driven gear 200C Since the toothless portion 202 faces the drive gear 100C, the driven gear 200C does not mesh with the drive gear 100C.

The paper feed roller 316 makes one rotation counterclockwise from the home position (rotation start position) shown in FIG. 1 and stops rotating. When the paper feed roller 316 is at the home position, the paper feed roller 316 is turned off. The toothless portion 202 of the driven gear 200C that makes one rotation is located at a position facing the drive gear 100C. That is, the position where the toothless portion 202 faces the drive gear 100C is the home position of the driven gear 100C.

When the driven gear 100C makes one rotation in the counterclockwise direction from the home position, the claw 205 at the tip of the armature 204 of the solenoid 203 is moved to the driven gear 100C.
Of the cam 206 formed integrally with the side surface of the cam 206. Thereby, the driven gear 100C
Is stopped at a position where the toothless portion 202 faces the drive gear 100C. When this rotation is stopped, the driven gear 100C
Are urged in the counterclockwise direction by the urging force of the coil spring 208.

One end of the coil spring 208 is hooked on a hook member 210 rotatably mounted on a shaft 209 provided on the side surface of the cam 206, and the other end is provided on a shaft provided on the sheet feeding unit 325. It is hooked on 211. The hook member 210 on which one end of the coil spring 208 is hooked rotates integrally with the driven gear 100C around the feed roller shaft 201C.

When the copy button of the image forming apparatus is pressed, the main motor 324 is turned on, and the drive gear 100 is turned on.
C rotates clockwise. Also, solenoid 2
03 is turned on for a predetermined time (several seconds) and the amateur 204
Is sucked, and the claw 205 is moved to the stopper portion 207 of the cam 206.
Get off. As shown in FIG. 3, the driven gear 200 </ b> C, in which the claw 205 is disengaged from the stopper portion 207 and the rotation restriction in the counterclockwise direction is released, rotates counterclockwise by the urging force of the coil spring 208, and The driving gear 100C rotating in the circumferential direction is engaged with the driving gear 100C.

Driven gear 2 meshed with drive gear 100C
00C continues to rotate in the counterclockwise direction, and is turned on by the urging force of the coil spring 212 when the solenoid is turned off.
The rotation stops when the claw 205 slidingly contacting the outer peripheral surface of the cam 06 engages with the stopper 207 of the cam 206. The rotation of the driven gear 200C causes the paper feed roller 316 to make one rotation, and feeds out the sheet S in the paper feed cassette 314.

The toothless portion 202 of the driven gear 200C
As shown in FIG. 4, a groove 213 for absorbing a shock at the time of meshing is provided on the rotation start end side. Also,
Some of the teeth on the rotation start end side are provided with cuts 214 for facilitating meshing even if the tooth tips interfere with each other.

Next, the relationship between the driving gear 100C and the driven gear 200C when the paper feeding unit 325 is attached to and detached from the image forming apparatus main body 323 will be described.

Normally, when the image forming apparatus main body 323 is stopped, the paper feed roller 316 stops rotating at the home position shown in FIG. Therefore, the worn paper feed roller 316
When the paper feeding unit 325 is detached from the image forming apparatus main body 323 for exchanging the image forming apparatus, the driving gear 100C and the driven gear 200C have a relationship shown in FIG. That is, the toothless portion 202 of the driven gear 200C faces the drive gear 100C, and the two gears 100C and 200C are not meshed.

The position of the driven gear 200C is determined by the pawl 2
05 and the rotation of the driven gear 200C and the coil spring 2
08, the urging force is continuously applied, so that the sheet feeding unit 325 in which the sheet feeding roller 316 has been replaced or the like is maintained when the image forming apparatus main body 323 is attached again. Therefore, when attaching the paper feeding unit 325 to the image forming apparatus main body 323, the driving gear 100
There is no interference between the tooth tips of C and the driven gear 200C.

When a jam occurs in the paper feeding unit 325 and the image forming apparatus main body 323 stops, the paper feeding roller 316 stops rotating while returning to the home position shown in FIG. Therefore, when the paper feed unit 325 is removed from the image forming apparatus main body 323 for the jam clearance, the toothless portion 202 of the driven gear 200C is further moved counterclockwise than the position shown in FIG. The gear 100C and the driven gear 200C are in an engaged state. In this state, the solenoid 203
Is off, and the claw 205 of the armature 204 urged by the coil spring 212 is in contact with the outer peripheral surface of the cam 206.

When the paper feed unit 325 is removed from the image forming apparatus main body 323 for jam clearance, the toothless portion 202 of the driven gear 200C is not located at a position facing the drive gear 100C as described above, so that the paper jam has occurred. After removing the sheet, the driven gear 200C is rotated counterclockwise by the operator's hand, and the pawl 205 is locked to the stopper 207 of the cam 206. In this case, the driven gear 200C is located at the home position shown in FIG.
When attaching to the image forming apparatus main body 323, the tooth tips of the drive gear 100C and the driven gear 200C do not interfere with each other. <Second Embodiment> FIGS. 6 to 8 show another example of the drive transmission mechanism for transmitting the drive of the main motor 324 to the paper feed roller 316. FIG.

FIG. 6 (and FIG. 8) shows the sheet feeding unit 325.
Indicates a state at the time when the image is set at a predetermined position of the image forming apparatus main body 323. In this case, the paper feeding unit 325
Is moved in the arrow X direction.

The first, second, and third drive gears 100D, 100, which are drive transmission elements, are provided on the image forming apparatus main body 323 side.
E, 100F are installed. First drive gear 100
D is fixed on the gear shaft 101, and the second drive gear 100E and the third drive gear 100F are fixed on the gear shaft 102. The first drive gear 100D meshes with the second drive gear 100E, and the third drive gear 100F meshes with a driven gear 200D installed on the paper feed unit side. Drive from the main motor 324 is transmitted to the first drive gear 100D.

First drive gear 100D and driven gear 200
D is a small-diameter gear, which is a full-tooth gear having teeth all around. The second drive gear 100E and the third drive gear 100F are large-diameter gears, and are toothless gears from which a plurality of teeth at one position on the outer periphery are removed. Here, the number of teeth of the third drive gear 100F is about one more than the number of teeth of the driven gear 200D, and the second drive gear
Less than 0E teeth. That is, the toothless portion 104 of the gear 100F is larger than the toothless portion 103 of the gear 100E.

The paper supply unit 325 is the main body 3 of the image forming apparatus.
23, the image forming apparatus main body 3
The driving gear 100F on the 23 side and the driven gear 200D on the paper feeding unit 325 side have a positional relationship in which the driving gear 100F can engage with each other. Since the toothless portion 104 faces the driven gear 200D, the driven gear 200D does not mesh with the driving gear 100F.
The toothless portion 103 of the driving gear 100E is
The drive gear 100E does not mesh with the drive gear 100D because the drive gear 100D faces 00D.

The paper feed roller 316 rotates one rotation counterclockwise from the home position (rotation stop position) shown in FIG. 1 and stops rotating. When the paper feed roller 316 is at the home position, the paper feed roller 316 is turned off. Toothless portion 10 of drive gear 100F meshing with driven gear 200D to make one rotation
Reference numeral 4 is at a position facing the driven gear 200D. That is, the position where the toothless portion 104 faces the driven gear 200D is the home position of the drive gear 100F. At this time, the toothless portion 103 of the drive gear 100E is also
00D.

When the drive gear 100F makes one rotation clockwise from the home position, the claw 107 at the tip of the armature 106 of the solenoid 105 is brought into contact with the stopper 109 of the cam 108 formed integrally with the side surface of the drive gear 100E. Lock. As a result, the driving gear 100F
The rotation stops at a position where the toothless portion 104 faces the driven gear 200D. The drive gear 100E is provided with the toothless portion 10
3 stops rotating at a position facing the drive gear 100D.
When the rotation is stopped, the drive gears 100E and 100F are urged clockwise by the urging force of the coil spring 110.

One end of the coil spring 110 is hooked on a hook member 112 rotatably mounted on a shaft 111 provided on the side surface of the cam 108, and the other end is provided on the image forming apparatus main body 323. It is hooked on the shaft 113. The hook member 112 on which one end of the coil spring 110 is hooked rotates around the gear shaft 102 integrally with the drive gears 100E and 100F.

When the copy button of the image forming apparatus is pressed, the main motor 324 is turned on, and the drive gear 100 is turned on.
D drives counterclockwise. Also, the solenoid 10
5 is turned on for a predetermined time (several seconds), the armature 106 is sucked, and the pawl 107 comes off the stopper 109 of the cam 108. As shown in FIG. 7, the pawl 107 is
09, the drive gears 100E and 100F whose clockwise rotation restriction has been released are rotated clockwise by the urging force of the coil spring 110, and
0E is a driving gear 100D rotating counterclockwise.
It comes to mesh with.

Drive gear 1 meshed with drive gear 100D
A few seconds after 00E starts rotating clockwise, drive gear 1
00F meshes with the driven gear 200D, and the driven gear 200D
D starts to rotate counterclockwise. When the solenoid is turned off, the pawl 107 urged by the urging force of the coil spring 116 and slidingly contacting the outer peripheral surface of the cam 108 comes into contact with the cam 1.
08 at the time of locking to the stopper 109 of the drive gear 1.
00E and 100F stop rotating. During this time, the sheet feeding roller 316 makes one rotation, and the sheet S in the sheet feeding cassette 314 is fed out.

Incidentally, grooves 114 and 115 for absorbing a shock at the time of engagement are provided on the rotation start end side of the toothless portions 103 and 104 of the drive gears 100E and 100F. In addition, some teeth on the rotation start end side are cut (not shown) so that they can easily mesh even if the tooth tips interfere with each other.

Next, the relationship between the driving gear 100F and the driven gear 200D when the paper feeding unit 325 is attached to and detached from the image forming apparatus main body 323 will be described.

Normally, when the image forming apparatus main body 323 is stopped, the paper feed roller 316 stops rotating at the home position shown in FIG. Therefore, the worn paper feed roller 316
When the paper feed unit 325 is detached from the image forming apparatus main body 323, for example, to exchange the drive gear 100F, the drive gear 100F and the driven gear 200D have the relationship shown in FIG. That is, the toothless portion 104 of the drive gear 100F is opposed to the driven gear 200D, and the gears 100F and 200D are not engaged.

The position of the drive gear 100F is determined by the position of the claw 1
07 and the coil spring 1
Since the urging force is continuously applied by the sheet feeding unit 10, the sheet feeding unit 325 having the sheet feeding roller 316 replaced or the like is maintained when the image forming apparatus main body 323 is attached again. Therefore, when attaching the paper feeding unit 325 to the image forming apparatus main body 323, the driving gear 100
There is no interference between the tooth tips of F and the driven gear 200D.

When a jam occurs in the sheet feeding unit 325 and the image forming apparatus main body 323 stops, the sheet feeding roller 316 stops rotating while returning to the home position shown in FIG. Accordingly, when the paper feeding unit 325 is removed from the image forming apparatus main body 323 for the jam clearance, the toothless portion 104 of the driving gear 100F is further moved clockwise than the position shown in FIG. 100F and the driven gear 200D are in an engaged state. In this state, the solenoid 105 is off, and the claw 107 of the armature 106 urged by the coil spring 116 is in contact with the outer peripheral surface of the cam 108.

In the case of this configuration example, when the paper feeding unit 325 is to be detached from the image forming apparatus main body 323 for jam clearance, the paper feeding unit 325 is attached to the image forming apparatus main body 32.
3, the main motor 324 is driven for a predetermined time. As a result, the driving gear 100F being rotated is rotated clockwise, and the pawl 1 is rotated.
07 is locked to the stopper portion 109 of the cam 108, and the rotation of the drive gear 100F is stopped at a position where the toothless portion 104 faces the driven gear 200D.

In this way, when the paper feed unit 315 after the jam processing is mounted on the image forming apparatus main body 323, the drive gear 100F is located at the home position shown in FIG. There is no interference between the tooth tips of 100F and the driven gear 200D.

As in this configuration example, the toothless gear (drive gear 1)
00F) is installed on the image forming apparatus main body 323 side and the all-tooth gear (the driven gear 200D) is installed on the paper feed unit 325 side, the electric component (solenoid) used as the rotation stop means of the toothless gear 105) can be installed on the image forming apparatus main body 323 side. Therefore, there is no need to connect the image forming apparatus main body 323 and the paper feed unit 325 (between the CPU and the electrical components) via a signal line, and the connector unit may have poor contact when the paper feed unit 325 is attached or detached. Can be prevented.

[0070]

As described above, in the drive transmission mechanism of the present invention, the first gear mounted on the machine body and the mechanical component unit removably mounted on the machine body. The second gear is meshed with the second gear, and the drive is transmitted from the first gear to the second gear. It is easy to reduce the size of the main body.

Also, one of the first gear and the second gear is a full-tooth gear having teeth on the entire circumference, and the other is a toothless gear from which a plurality of outer teeth are removed. When the mechanical part unit is mounted on the machine main body, the toothless portion of the toothless gear is made to face the all gears. Therefore, when the mechanical part unit is mounted on the machine main body, the first gear and the second gear are connected. Gear tips do not interfere with each other. Therefore, the first
The backlash between the first gear and the second gear can be reduced, noise and vibration are reduced, and drive transmission efficiency is improved.

The toothless gear can also be used as a one-turn clutch.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing an overall configuration of an image forming apparatus (electrophotographic copying machine) to which the present invention is applied.

FIG. 2 is a side view showing a configuration example (1) of the drive transmission mechanism of the present invention.

FIG. 3 is a side view showing a configuration example (1) of the drive transmission mechanism of the present invention.

FIG. 4 is an enlarged side view showing a part of a driven gear of the drive transmission mechanism.

FIG. 5 is a perspective view showing a configuration example (1) of a drive transmission mechanism of the present invention.

FIG. 6 is a side view showing a configuration example (2) of the drive transmission mechanism of the present invention.

FIG. 7 is a side view showing a configuration example (2) of the drive transmission mechanism of the present invention.

FIG. 8 is a perspective view showing a configuration example (2) of the drive transmission mechanism of the present invention.

FIG. 9 is a side view showing a configuration of a drive transmission mechanism of a conventional example (1).

FIG. 10 is a side view showing a configuration of a drive transmission mechanism of a conventional example (2).

[Explanation of symbols]

100C, 100F Driving gear (first gear) 105, 203 Solenoid (rotation stopping means) 107, 205 Claw 108, 206 Cam (rotation stopping means) 200C, 200D Driven gear (second gear) 110, 208 Coil spring ( Biasing means) 323 image forming apparatus main body (machine main body) 324 main motor (drive source) 325 paper feed unit (machine part)

Claims (7)

[Claims] 1. A first gear installed on a machine body side, and a second gear installed on a machine component unit side detachably attached to the machine body and meshing with the first gear. And a drive transmission mechanism for transmitting the drive of a drive source provided in the machine body to the machine component unit via the first gear and the second gear. Either one of the first gear and the second gear is a full-tooth gear having teeth all around its circumference, and the other is a toothless gear from which a plurality of teeth on the outer circumference are removed. A rotation stopping means for stopping the rotation of the gear at a position where the toothless portion faces the all-tooth gear. 2. The machine according to claim 1, wherein the first gear on the machine body side is a full-tooth gear, and the second gear on the machine component unit side is a toothless gear. Drive transmission mechanism. 3. The machine according to claim 1, wherein the first gear on the machine body side is a toothless gear, and the second gear on the machine component unit side is a full-tooth gear. Drive transmission mechanism. 4. The rotation-stopping means includes a one-rotation cam that rotates integrally with the toothless gear, and a claw portion that is locked by a stopper part of the one-rotation cam that makes one rotation to rotate the toothless gear. The drive transmission mechanism according to claim 1, wherein a solenoid for stopping the drive is used. 5. The drive transmission mechanism according to claim 1, further comprising an urging unit that urges the toothless gear that has stopped rotating by the rotation stopping unit in a rotation direction. 6. The drive transmission mechanism according to claim 5, wherein a coil spring is used as said urging means. 7. An image forming apparatus main body, a component unit detachably attached to the image forming apparatus main body, and a drive source installed in the image forming apparatus main body.
A first gear provided on the image forming apparatus main body side and a second gear provided on the component unit side and meshing with the first gear; Wherein the first gear and the second gear are provided with teeth all around the image forming apparatus. Rotation stop means for stopping the rotation of the toothless gear at a position where the toothless portion faces the all-tooth gear, while the other is a toothless gear from which one tooth on the outer periphery is removed. And an urging means for urging the toothless gear, which has stopped rotating by the rotation stopping means, in a rotational direction.