JPH11190401A - Driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device in which noise is a little even if it is rotated at high speed, a big driving force can be exactly transmitted and a cost is reduced. SOLUTION: A whirl-stop 82 made of metal is mounted on an output shaft 81 of a main motor 38, and a motor output gear 40 which is a helical gear made of a resin is mounted on the whirl-stop 82. Thus, at the time of driving of the main motor 38, a heat generated from the main motor 38 is not directly transmitted to the motor output gear 40 made of the resin, while the whirl-stop 82 made of metal is exactly secured to the output shaft 81 without expansion. Since the motor output gear 40 is the helical gear made of a resin, engagement thereof is stronger than that of a spur gear. Therefore, noise due to gear noise can be reduced and the big driving force can be exactly transmitted, and since the helical gear is made of a resin, big reduction of the cost is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power device, and more particularly to a power device,
It relates to a driving device.

[0002]

2. Description of the Related Art For example, an image forming apparatus such as a printer usually uses a motor as a drive source. A metal spur gear is attached to the output shaft of such a motor as a motor output gear.

[0003]

In recent years, as the image forming speed has been required to be increased, it has become necessary to increase the speed of the driving member. Therefore, if a high-output motor is used to rotate at high speed, the noise caused by gear noise will increase if the output gear of the motor is a spur gear with a gear groove cut parallel to the axial direction. Also, it is difficult to reliably transmit large power. On the other hand, if a bevel gear with a gear groove cut obliquely to the axial direction is used as the output gear of the motor, the meshing of the gears is larger than that of the spur gear, so that noise due to gear noise is small, and Suitable for high load and high speed transmission.

However, since the bevel gear is usually formed by cutting a metal, when the bevel gear is used as the output gear of the motor, there arises a problem that the machining cost is increased. On the other hand, if the helical gear is formed of resin, the cost is reduced, but if the helical gear is used as the output gear of the motor, the resin expands with respect to the output shaft due to the heat generated by the motor when the motor is driven. However, the gear may run idle with respect to the output shaft. In this case, idling can be prevented by performing knurling or the like on the motor shaft. However, if knurling is performed directly on the motor shaft, the cost increases and the cost reduction due to the use of resin is offset.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to transmit a large amount of power with low noise even when rotated at a high speed. It is to provide a drive device in which the number is reduced.

[0006]

According to a first aspect of the present invention, there is provided a driving device in which a resin bevel gear is mounted on an output shaft of a driving source.
A metal detent for preventing relative rotation of the bevel gear with respect to the output shaft is mounted around the output shaft, and the bevel gear is mounted around the detent. It is characterized by.

According to such a structure, the metal detent is attached to the output shaft of the drive source, and the resin bevel gear is attached to the detent, so that the drive source is driven when the drive source is driven. Is not transmitted directly to the resin bevel gear. Therefore, the bevel gear made of resin is firmly fixed to the detent, and since the detent is made of metal, it is firmly fixed without expanding to the output shaft. Accordingly, the relative rotation of the resin bevel gear with respect to the output shaft is prohibited, and large drive can be transmitted reliably.

[0008] The invention described in claim 2 is the first invention.
In the invention described in (1), the detent is press-fitted into the output shaft, and the bevel gear is press-fitted into the press-fitted detent. By press-fitting the detent into the output shaft and press-fitting the bevel gear into the press-fitted detent, the resin bevel gear can be easily and reliably attached to the output shaft of the drive source.

[0009] The invention described in claim 3 is the first invention.
Wherein the bevel gear is molded with the detent inserted, and the integrated bevel gear and the detent are press-fitted into the output shaft. And If a detent is pressed into the output shaft and the helical gear is pressed into the pressed detent, it is necessary to insert the detent into the helical gear twice. When integrally formed, the integrated helical gear and detent can be attached to the output shaft by one press-fitting. Therefore, shaft run-out and deformation due to press-fitting can be reduced as compared with the case of mounting by two press-fits.

[0010] The invention described in claim 4 is the first invention.
In the invention described in any one of (3) to (3), irregularities for prohibiting relative rotation of the helical gear with respect to the detent are formed on a part or the entire outer periphery of the detent. . When the drive source is driven, the heat generated by the drive source causes the resin bevel gear to expand with respect to the metal detent, thereby causing the detent to idle. On the outer circumference,
Since irregularities are formed to prohibit relative rotation of the bevel gear with respect to the detent, such idling can be prevented by engagement of the irregularities with the bevel gear.

[0011] The invention described in claim 5 is the same as in claim 4.
In the invention described in (1), the unevenness is formed only in a predetermined range in the axial direction of the outer periphery of the detent. The part of the bevel gear that faces the irregularities formed on the outer periphery of the detent is deformed along the irregular shape, and the accuracy of the gear in that part may be reduced. By forming it only in the range, the outer peripheral portion of the detent with no irregularities is secured, and the portion of the bevel gear facing the outer peripheral portion of the detent with no irregularities is formed with another gear. By using it for meshing with the gear, good use can be achieved without lowering the precision of the gear.

According to a sixth aspect of the present invention, a driving device according to any one of the first to fifth aspects is used as a driving source of an image forming apparatus. By using the driving device according to any one of claims 1 to 5 as a driving source of the image forming apparatus, noise caused by gear noise during operation of the image forming apparatus is small, and large power is reliably transmitted to the driving member. be able to.

[0013]

FIG. 1 is a side sectional view showing a main part of a laser printer as an embodiment of an image forming apparatus having a driving device according to the present invention. As shown in FIG. 1, the laser printer 1 includes a paper feed tray 3 provided on a rear upper side of a main body case 2 and an openable top cover 4 provided on a front upper side of the main body case 2. , Its appearance is configured.

A power supply substrate 32, a control substrate 33, a paper transport mechanism 5 as a recording medium supply means, a scanner unit 6, a process unit 7 as an image forming means, and a fixing unit as a fixing means are provided in the main body case 2. A process unit 7 is disposed downstream of the sheet transport mechanism 5, and a fixing unit 8 is disposed downstream of the process unit 7.

The paper feed tray 3 is detachably attached to the main body case 2, and sheets are set on the paper feed tray 3 in a stacked manner. The paper transport mechanism 5 is disposed downstream of the paper feed tray 3 and upstream of a recording material supply unit, which will be described later, and includes a pickup roller 9 for feeding stacked sheets one by one; And a registration roller 10 for transporting the sheet sent from the printer 9 to the process unit 7. The paper fed from the paper feed tray 3 by the pickup roller 9 is a registration roller 10
The registration roller 10 is conveyed to the process unit 7 by a predetermined registration operation, that is, after the registration roller 10 is once rotated in the reverse direction to align the leading ends of the sheets.

The scanner unit 6 is disposed below the process unit 7 and has a laser light emitting unit (not shown), a polygon mirror 11, reflection mirrors 12 and 13, a lens 14, and the like. Then, a laser beam based on predetermined image data emitted from the laser emitting section is passed or reflected in the order of the polygon mirror 11, the lens 14, the reflecting mirror 12, and the reflecting mirror 13 as shown by a chain line, and a process described later is performed. Irradiation is performed on the surface of the photosensitive drum 17 of the unit 7 by high-speed scanning.

FIG. 2 is a side sectional view showing the process unit 7 in an enlarged manner. Next, the process unit 7 will be described with reference to FIG. The process unit 7 includes, in its unit case 16, a toner box 23 containing a toner as a recording agent, a photosensitive drum 17 as an electrostatic latent image carrier, and supplying toner to the photosensitive drum 17 to form a static image. A toner supply unit 15 as a recording agent supply unit for developing an electrostatic latent image, that is, a developing roller 18, a supply roller 19, an agitator 25 in a toner box 23, a scorotron charger 20, a transfer roller 21, and a cleaning unit Roller 22, blade 37, two auger members 3
5 and 36 are accommodated.

The process unit 7 includes a main body case 2
It has a cartridge structure that can be attached to and detached from a predetermined portion of the inside. When the process unit 7 is detached from the main body case 2, the toner can be supplied by mounting the toner box 23 to the process unit 7. I have. The toner in the toner box 23 is agitated by the agitator 25 and discharged from the toner supply port 26 opened on the downstream side of the toner box 23. The toner used here is a non-magnetic one-component toner.

A supply roller 19 is rotatably disposed at a position on the downstream side of the toner supply port 26, and a position downstream of the supply roller 19 and opposed to the supply roller 19. , A developing roller 18 is rotatably disposed. The photosensitive drum 17 includes a developing roller 18
At a side position on the downstream side of the developing roller 18, the developing roller 18 is in contact with the developing roller 18 and is rotatably disposed. A portion of the surface of the photosensitive drum 17 which is in contact with the developing roller 18 is charged by a scorotron charger 20 disposed below the photosensitive drum 17, and the laser beam from the scanner unit 6 described above is charged. To form an electrostatic latent image based on predetermined image data.

The toner discharged from the toner supply port 26 is supplied to the developing roller 1 by the rotation of the supply roller 19.
8 and is carried as a thin layer of a certain thickness on the developing roller 26 by a blade 37 extending from the upper inner wall of the unit case 16 toward the developing roller 18.
At this time, the toner supplied to the developing roller 18 is charged by frictional contact between the supply roller 19 and the developing roller 18.

A constant voltage DC power supply device (not shown) applies a constant voltage bias to the shaft of the developing roller 18 such that the toner carried from the developing roller 18 moves toward the electrostatic latent image on the photosensitive drum 17. Voltage is applied. When the toner carried on the developing roller 18 comes into contact with the photosensitive drum 17 due to the rotation of the developing roller 18, the toner forms an electrostatic latent image formed on the surface of the photosensitive drum 17. Development is performed by the attachment.

A transfer roller 21 facing the photosensitive drum 17 is disposed above the photosensitive drum 17, and the toner adhered to the electrostatic latent image is transferred to the photosensitive drum 17 by a paper. 21 so that the image is transferred to a sheet. The sheet on which the toner has been transferred is sent to a fixing unit 8 disposed downstream of the photosensitive drum 17.

The toner remaining on the surface of the photosensitive drum 17 is removed from the cleaning roller 2 disposed on the side of the photosensitive drum 17 so as to face the photosensitive drum 17.
2 and temporarily collected by the developing roller 18 via the photosensitive drum 17 at a predetermined timing. Further, the toner supply port 2 of the toner box 23
6, two auger members 35 and 36 are rotatably disposed at positions near the respective auger members 35 and 3.
6 uniformly distributes the toner discharged from the toner supply port 26 in the unit case 16.

As shown in FIG. 1, the fixing unit 8 fixes the toner transferred from the photosensitive drum 17 of the process unit 7 onto the sheet by heat, and comprises a heating roller 28, a heating roller And a pressing roller 29 pressed by the pressing roller 28. The toner transferred to the sheet sent from the process unit 7 to the fixing unit 8 is heat-fixed by the heating roller 28 and the pressing roller 29, and thereafter, the downstream side of the rollers 28 and 29. The sheet is ejected onto a sheet ejection tray 31 by a pair of ejection rollers 30 for ejecting the sheet to the outside of the main body case 2.

FIG. 3 is an explanatory diagram showing a drive system of the laser printer 1 configured as described above, and FIG. 4 is an explanatory diagram showing a drive system driven by a main motor described later in the drive system shown in FIG. FIG. 5 is an explanatory diagram showing a drive system driven by a sub motor described later in the drive system shown in FIG. A main drive system of the laser printer 1 will be described with reference to FIGS.

As shown in FIG. 3, this laser printer 1
Is provided with two drive sources, a main motor 38 and a sub motor 39. The main motor 38 and the sub motor 39 are used to drive the above-mentioned components, that is, the paper transport mechanism 5,
The process unit 7 and the fixing unit 8 are driven. The main motor 38 has a higher output performance than the sub motor 39.

As shown in FIG. 4, the main motor 38
The toner supply unit 15 for supplying toner to the photosensitive drum 17, that is, the developing roller 18, the supply roller 19, and the agitator 25 in the toner box 23 are arranged below the paper transport mechanism 5, and the paper is driven. The transport mechanism 5, that is, the pickup roller 9 and the registration roller 10 are driven.

From the main motor 38 to the toner supply means 15
To the motor output gear 40 of the main motor 38.
From the first gear 4 which is arranged to mesh with each other.
The first gear 42 is transmitted to the agitator gear 45 for rotating the agitator 25 in the toner box 23 via the second gear 42, the third gear 43, and the fourth gear 44, and then the fifth gear meshes with the fourth gear 44. The light is transmitted through a gear 46 to a left developing roller gear 47 provided at the left end of the developing roller 18. The drive from the main motor 38 is transmitted to the agitator 25 and the developing roller 18 by these gear trains. These gear trains are arranged on the left side in the main body case 2. Next, the driving is performed via the developing roller 18 from the right developing roller gear 48 provided at the right end of the developing roller 18. Is transmitted to a sixth gear 49 disposed on the right side, and is transmitted to the supply roller gear 50 provided at the right end of the supply roller 19 via the sixth gear 49.

As described above, the main motor 38 is driven by the toner supply means 15, ie, the developing roller 18, the supply roller 19, and the first gear 41 through the sixth gear 49.
And the agitator 25 in the toner box 23 is driven. In such a drive system of the toner supply unit 15,
A relatively large driving force is required to supply the toner, especially to drive the agitator 25 that stirs the toner. For this reason, the high-output main motor 38 is arranged near the toner supply unit 15 so that the toner supply unit 15 can be driven at a high output via the gear train described above.

In the driving system of the toner supply means 15, a seventh gear 51 is meshed with the right developing roller gear 48, and the seventh gear 51 is provided on the side of the two auger members 35 and 36. Auger member gears 52 and 53 provided at the end portions are in mesh with each other.
Therefore, in the main motor 38, the two auger members 35 and 36 are also driven by such a drive system of the toner supply unit 15.

On the other hand, the drive from the main motor 38 to the paper transport mechanism 5 side is performed from the first gear 41 via an eighth gear 54, a ninth gear 55, and a tenth gear 56, which are disposed so as to mesh with each other. Is transmitted to a pickup roller gear 57 provided at a side end of the pickup roller 9, and then to an eleventh gear 58 meshing with the tenth gear 56.
Is transmitted to a registration roller gear 59 provided at a side end portion of the registration roller 10 through the control unit. In this way,
In the drive system to the paper transport mechanism 5 side, the main motor 38 is driven via the eighth gear 54 to the eleventh gear 58.
The pickup roller 9 and the registration roller 10 are driven.

Further, as shown in FIG.
Is disposed below the photosensitive drum 17, drives the photosensitive drum 17, and drives the heating roller 28 and the pressing roller 29 provided in the fixing unit 8. The drive from the sub motor 39 to the photoconductor drum 17 side is performed by a motor output gear 61 of the sub motor 39 via a thirteenth gear 62, a fourteenth gear 63, and a fifteenth gear 64 which are disposed so as to mesh with each other. Drum 1
7 is transmitted to the photosensitive drum gear 65 provided at the side end of the drum 7. As a result, the drive from the sub motor 39 is transmitted to the photosensitive drum 17 via the thirteenth gear 62 to the fifteenth gear 64. In such a drive system to the photosensitive drum 17 side, it is necessary to accurately rotate and drive so that an electrostatic latent image is formed favorably. Therefore, the sub motor 39 is disposed near the photosensitive drum 17 and has a drive transmission mechanism that is as simple as possible, that is, a small gear train (in the present embodiment, the thirteenth gear 62 and the fourteenth gear 63).
And three intermediate gears of the fifteenth gear 64).

In the driving system for the photosensitive drum 17, a cleaning roller gear 66 provided at a side end of the cleaning roller 22 meshes with the fifteenth gear 64. A transfer roller gear 67 provided at a side end of the transfer roller 21 meshes with 65. Therefore, in the sub motor 39, the cleaning roller 22 and the transfer roller 21 are also driven by such a drive system toward the photosensitive drum 17 side.

On the other hand, from the sub motor 39 to the fixing unit 8
To the side, the sixteenth gear 68 and the first gear 64, which are arranged to mesh with each other,
The power is transmitted to a heating roller gear 70 provided at a side end of the heating roller 28 via a seven gear 69. As described above, in the drive system toward the fixing unit 8, the sub motor 39 drives the heating roller 28 via the thirteenth gear 62 to the seventeenth gear 69. The pressing roller 29 is driven by the rotation of the heating roller 28.

According to such a configuration, the main motor 3
8, the sub-motor 39 drives the toner supply unit 15 at a high output required to increase the image forming speed, while the photoconductor drum 17 is required to form good image quality. It can be driven with accuracy. Therefore, the toner supply unit 15 and the photosensitive drum 17 can be appropriately driven according to the respective required driving, and a good image can be formed, and the image forming speed can be increased. .

Further, the pickup roller 9 and the registration roller 10 provided in the paper transport mechanism 5 and the heating roller 28 provided in the fixing unit 8 do not require a driving force as large as that of the toner supply means 15. It is not necessary to drive with a precision as high as 17. Therefore, the pickup roller 9 and the registration roller 10 arranged on the upstream side of the toner supply unit 15 are connected to the main motor 38.
In addition, by driving the heating roller 28 disposed downstream of the photosensitive drum 17 by the sub-motor 39, power can be efficiently applied to each appropriately disposed driving member with a minimum gear train. The transmission can be performed, and each driving member can be efficiently driven.

Further, since the output of the main motor 38 is higher than that of the sub motor 39, the toner supply means 15 can be driven with a higher output. Therefore, the image forming speed is further increased. On the other hand, the sub motor 39
Does not require a higher output than the main motor 38,
An inexpensive motor with a lower output than the main motor 38 can be used, and the cost can be reduced.

In the drive system of the sub motor 39,
The sub motor 39 and the photosensitive drum 17 are connected via three intermediate gears (the thirteenth gear 62 to the fifteenth gear 64), but the sub motor 39 and the heating roller 28 are further two, that is, five. Intermediate gear (13th gear 6
In other words, the sub motor 39 is connected to the heating roller 28 through the second through seventeenth gears 69).
It is connected to the photosensitive drum 17 by a smaller number of transmission stages (corresponding to the number of gears in the present embodiment).
Therefore, the power from the sub motor 39 is transmitted to the photosensitive drum 17 with less loss than that transmitted to the heating roller 28. Therefore, the power of the sub motor 39 can be accurately and reliably transmitted to the photosensitive drum 17, thereby further improving the accuracy.

In this embodiment, resin helical gears are used as the motor output gears 40 and 61 of the main motor 38 and the sub motor 39 used as the drive device of the laser printer 1. Hereinafter, the mode will be described taking the main motor 38 as an example. FIG. 6 is a sectional view around the motor output gear 40 provided on the main motor 38. As shown in FIG. 6, the output shaft 81 of the main motor 38 is made of metal, and a metal detent 82 having a cylindrical shape is attached around the output shaft 81. A motor output gear 40 composed of a resin bevel gear is mounted around 82.

That is, the detent 82 is for inhibiting the relative rotation of the motor output gear 40 with respect to the output shaft 81.
The main motor 38 is inserted into the through hole 83.
Output shaft 81 is inserted. A through hole 84 is also formed in the center of the motor output gear 40, which is a resin helical gear, in the axial cross section.
2 outer peripheral portion 85 is inserted.

As described above, since the rotation stopper 82 is interposed between the output shaft 81 and the motor output gear 40, when the main motor 38 is driven, the heat generated from the main motor 38 is directly transmitted to the motor output gear 40 made of resin. Without being transmitted
Therefore, the motor output gear 40 made of resin is
2 and the detent 82 is made of metal, so that it is firmly fixed to the output shaft 81 made of the same metal without expanding. by this,
Relative rotation of the resin-made motor output gear 40 with respect to the output shaft 81 is prohibited, and the drive from the main motor 38 is reliably transmitted. The motor output gear 40 is a bevel gear having a gear groove obliquely formed in the axial direction. The meshing of the gears increases, so that noise due to gear noise can be reduced and large power can be transmitted reliably. In addition, since the motor output gear 40 having the helical teeth is formed of resin,
Compared to the case where a metal bevel gear is used as the motor output gear 40, a significant cost reduction can be achieved.

The rotation stop 82 and the motor output gear 40 are connected to the output shaft 8 by the following two methods.
Attach to 1. First, the first method will be described with reference to FIG. That is, in the first method, the detent 82 is pressed into the output shaft 81, and then the motor output gear 40 is pressed into the detent 82. According to such a method, the main motor 3
Since the motor output gear 40 can be attached to the output shaft 81 of FIG. 8, the cost of the driving device can be reduced.

The second method will be described with reference to FIGS. In the second method, first, as shown in FIG. 8, both are integrally formed with the detent 82 inserted in the motor output gear 40. Then, as shown in FIG. 9, the integrated rotation stopper 82 and the motor output gear 40 are pressed into the output shaft 81. The first shown in FIG.
According to the method described above, the detent 82 and the motor output gear 4
Although two press-fittings are required to attach 0,
If the motor 2 and the motor output gear 40 are formed integrally, they can be attached to the output shaft 81 by one press-fitting. Therefore, as compared with the first method shown in FIG. 7, shaft run-out and deformation due to press fitting can be reduced, and the accuracy of the gear can be improved. In addition, detent 82
By integrally forming the motor output gear 40 and the motor output gear 40, the coupling force between the detent 82 and the motor output gear 40 is strengthened, and the rotational torque of the main motor 38 is more reliably reduced by the first method than in the first method shown in FIG. It can be transmitted to the gear 41.

Further, as shown in FIG. 7, in the first method, unevenness 86 is formed by knurling at one end in the axial direction of the outer periphery of the detent 82.
The unevenness 86 inhibits the relative rotation of the motor output gear 40 with respect to the rotation stop 82. When the main motor 38 is driven, heat generated from the main motor 38 causes the resin motor output gear 40 to The protrusions and recesses 86 engage with the inner peripheral surface of the motor output gear 40 made of resin when it expands with respect to the detent 82 made of a resin and thereby tries to idle the detent 82. This prevents such idling.
Therefore, idling is prevented by the unevenness 86,
Power can be transmitted well.

Further, the outer peripheral portion of the motor output gear 40 facing the unevenness 86 may be deformed along the shape of the unevenness 86, and the accuracy of the gear at the outer circumferential portion may be reduced. When the motor output gear 40 is attached to the rotation stopper 86, the deformation is large.
However, the unevenness 86 is formed only at one end in the axial direction of the outer periphery of the rotation stopper 82, and has an outer peripheral portion 87 in which the unevenness 86 of the rotation stopper 82 is not formed, as shown in FIG. In addition, by using the outer peripheral portion of the motor output gear 40 facing the outer peripheral portion 87 of the detent 80 on which the unevenness 86 is not formed, by engaging with the first gear 41 (in FIG. The unevenness 86 is formed only at the lower end, and the first gear 41
Are engaged with the outer peripheral portion of the motor output gear 40 facing the upper end of the rotation stopper 82 where the unevenness 86 is not formed, that is, the upper end of the motor output gear 40. ), Good use can be achieved without reducing the precision of the gear.

Further, as shown in FIG. 8, in the second method, unevenness 86 is formed by knurling on the entire outer periphery of the detent 82. In the second method shown in FIG. 8, since the rotation stopper 82 is integrally formed in a state inserted into the motor output gear 40, the outer periphery of the motor output gear 40 opposed to the unevenness 86 is compared with the case of press-fitting. Less deformation of parts. Therefore, detent 8
The unevenness 86 is formed on the entire surface of the motor 2, and the engaging force of the unevenness 86 on the motor output gear 40 made of resin is strengthened, so that the relative rotation of the motor output gear 40 with respect to the detent 82 is more reliably prohibited.

As described above, by using a drive device using resin bevel gears for the motor output gears 40 and 61 of the main motor 38 and the sub motor 39 in the laser printer 1, the main unit is operated when the laser printer 1 is operated. Noise due to gear noise of the motor 38 and the sub motor 39 is small, and large power can be reliably transmitted to each drive member. Accordingly, noise during operation of the laser printer 1 can be reduced, and the image forming speed can be increased.

In this embodiment, the main motor 38
The sub motor 39 and the sub motor 39 are controlled integrally by the CPU provided on the control board 33 without being distinguished from each other. Is also good. Further, the main motor 38 and the sub motor 39 as the driving device in the present embodiment may be, for example, a DC motor or a stepping motor.

[0049]

As described above, according to the first aspect of the present invention, a bevel gear made of resin can be used as the output gear of the drive source. Larger power can be reliably transmitted at high speed while reducing noise caused by gear noise. In addition, since the bevel gear is formed of resin, a metal bevel gear is used. Compared with the case, the cost can be significantly reduced.

According to the second aspect of the present invention, the resin bevel gear can be attached to the output shaft of the drive source by a simple method, so that the cost of the drive device can be reduced. According to the third aspect of the present invention, the integrated helical gear and the detent can be attached to the output shaft by one press-fitting. Shaft runout and deformation can be reduced. Therefore, the accuracy of the gear can be improved.

According to the fourth aspect of the invention, the relative rotation of the bevel gear with respect to the detent is prohibited by the unevenness formed on the outer periphery of the detent, so that the bevel gear idles with respect to the detent. Power can be transmitted satisfactorily, According to the invention described in claim 5, by forming the irregularities only in a predetermined range of the outer periphery of the detent, the outer peripheral portion of the detent having no irregularities is secured, and the irregularities are formed. By using the portion of the bevel gear facing the outer peripheral portion of the non-rotating gear for meshing with another gear, good use can be achieved without lowering the precision of the gear.

According to the sixth aspect of the present invention, noise during operation of the image forming apparatus can be reduced, and the image forming speed can be increased.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part showing a laser printer as an embodiment of an image forming apparatus including a driving device of the present invention.

FIG. 2 is an enlarged side sectional view showing a process unit of the laser printer shown in FIG.

FIG. 3 is an explanatory diagram showing a drive system of the laser printer shown in FIG.

FIG. 4 is an explanatory diagram showing a drive system driven by a main motor in the drive system shown in FIG. 3;

FIG. 5 is an explanatory diagram showing a driving system driven by a sub motor in the driving system shown in FIG. 3;

FIG. 6 is a cross-sectional view around a motor output gear provided in the main motor shown in FIG. 3;

FIG. 7 is an explanatory diagram illustrating a first method for attaching a motor output gear to an output shaft of a main motor.

FIG. 8 is an explanatory diagram illustrating a second method for attaching a motor output gear to an output shaft of a main motor.

FIG. 9 is an explanatory diagram illustrating a second method for attaching a motor output gear to an output shaft of a main motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer 38 Main motor 39 Sub motor 40 Motor output gear 61 Motor output gear 82 Non-rotating 86 Unevenness

Claims (6)

[Claims] 1. A drive device in which a resin bevel gear is attached to an output shaft of a drive source, wherein relative rotation of the bevel gear with respect to the output shaft is prohibited around the output shaft. A drive device, wherein a metal detent is attached, and the bevel gear is attached around the detent. 2. The drive device according to claim 1, wherein the detent is press-fitted into the output shaft, and the helical gear is press-fitted into the press-fitted detent. 3. The bevel gear is formed with the detent inserted therein, and the integrated bevel gear and the detent are pressed into the output shaft. The drive device according to claim 1, wherein 4. A part of or the entire outer periphery of the detent is formed with irregularities for inhibiting relative rotation of the bevel gear with respect to the detent.
The drive device according to claim 1. 5. The driving device according to claim 4, wherein the unevenness is formed only in a predetermined range in an axial direction of an outer periphery of the detent. 6. The driving device according to claim 1, which is used as a driving source of an image forming apparatus.