JPH09204084A - Driving device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the tilt of a driving shaft coupled to an output shaft side driven by a motor through a belt. SOLUTION: This driving device is provided with a motor unit 2 equipped with the motor 9 and the output shaft 10 driven by the motor 9, and a driving shaft unit 3 equipped with the driving shaft 16 coupled and connected to a part to be driven and fixed on an image forming device main body side; and two units 2 and 3 are coupled by a coupling mechanism 4 in a state where the belt 28 can be laid between pulleys 12 and 19 fixed on the output shaft 10 and the driving shaft 16, and fixed by a fixing mechanism 5. By fixing the unit 3 to a jig in the case of setting the tension of the belt 28, the tilt of the driving shaft 16 caused by the increase of the tension of the belt 28 is easily found out, so that the tension of the belt 28 is accurately set without depending on intuition. Therefore, the driving shaft 16 is accurately attached to the image forming device main body without causing the tilt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for driving a driven portion such as an image forming process portion or a sheet conveying portion in an image forming apparatus, and is particularly suitable for use in a color image forming apparatus. A drive device.

[0002]

2. Description of the Related Art An example of a conventional device of this type is shown in FIGS. The drive device shown in FIGS. 3 and 4 is composed of a motor unit 101 and a drive shaft unit 102. The motor unit 101 includes a motor 103 and an output shaft 104 to which rotational driving force is applied to the motor 103.
And a drive pulley 105 is fixed to the output shaft 104. The drive shaft unit 102 is a main frame 106 of the image forming apparatus main body (not shown).
A drive shaft 109 is rotatably mounted in a housing 107 fixed to the shaft via a pair of bearings 108, a driven pulley 110 is fixed to one end of the drive shaft 109, and a coupling 111 is fixed to the other end. Has been done. The coupling 111 is the driven portion 1 on the image forming apparatus main body side.
12, for example, is connected and coupled to the input shaft of the photosensitive drum or the input shaft of the paper transport mechanism. The motor unit 101 is fixed to the main frame 106 of the image forming apparatus main body with screws 114 while the belt 113 is stretched between the drive pulley 105 and the driven pulley 110. In this case, the mounting hole 115 on the side of the motor unit 101 into which the screw 114 is inserted has the output shaft 104 and the drive shaft 10.
It is formed in a long and slender long hole shape in a straight line connecting 9 and 9.
Therefore, by freely setting the position of the mounting hole 115 with respect to the screw 114, the output shaft 104 and the drive shaft 10
The distance between the shaft and the shaft 9 is variable.

In such a structure, the driving force of the motor 103 output to the output shaft 104 of the motor unit 101 is transmitted from the driving pulley 105 to the driven pulley 110 of the driving shaft unit 102 via the belt 113. The rotational driving force is transmitted to the driven portion 112 of the image forming apparatus main body via the coupling 111 fixed to the other end of the drive shaft 109. At this time, since the power is transmitted by the belt driving method using the belt 113, there is no gear backlash inevitable in the gear driving method, and the driven portion 112 can be rotationally driven with high accuracy. Therefore, the driving device as illustrated in FIGS. 3 and 4 is suitable for use in a color image forming apparatus, such as a color laser beam printer or a color copying machine, which requires strict accuracy in the alignment of each color.

FIG. 5 shows an example of a color laser beam printer. That is, the image forming process unit 155 is arranged in the order of yellow, magenta, cyan, and black in the conveying path 154 of the transfer paper 153 from the paper feeding unit 151 to the paper discharging unit 152, and fixing is performed on the downstream side thereof. A device 156 is located. Then, from the paper feeding unit 151 to the transport path 1
The transfer sheet 153 fed to the sheet 54 is made yellow by a sheet conveying mechanism 160 formed by a conveying belt 159 being stretched between a driving roller 157 and a driven roller 158.
The image forming process unit 155 is guided in the order of magenta, cyan, and black, and each image process unit 155 forms an image of each color. That is, in each image forming process unit 155, the surface of the photosensitive drum 162 uniformly charged by the charger 161 is irradiated with a laser beam from the optical writing unit 163 to form a desired electrostatic latent image. The electrostatic latent image is developed by the developing device 164 to form a toner image, and the toner image is transferred to the transfer paper 153 by the transfer roller 165. Then, the residual toner remaining on the photosensitive drum 162 after the transfer is removed by the toner cleaner 166, and the charged image on the photosensitive drum 162 is neutralized by the static eliminator 167 to prepare for the next image forming process. On the other hand, the transfer paper 153 on which the toner image has been formed is sent to the fixing device 156, where the toner image is fixed by heating and pressurization, and then discharged to the paper discharge unit 152.

The driving device illustrated in FIGS. 3 and 4 is, for example, the image forming process unit 155 and the paper transport mechanism 1 in the color image forming apparatus illustrated in FIG.
It is used as a driving unit of 60. That is, for example, the photosensitive drum 162 in the image forming process unit 155 is the driven unit 1.
22 or the drive roller 157 of the paper transport mechanism 160 becomes the driven portion 122, and the photosensitive drum 162, the drive roller 157, etc. are coupled to the coupling 111 of the drive shaft 109. As a result, the drive device takes advantage of the belt drive system, drives the image forming process unit 155 and the paper transport mechanism 160 with high accuracy, and contributes to the formation of a high-quality color image without color misregistration.

[0006]

In the drive device of the belt drive system as illustrated in FIGS. 3 and 4, the belt 113 is used.
Must be stretched between the two pulleys 105 and 110 with a predetermined tension without slipping. Therefore, in the drive device illustrated in FIGS. 3 and 4,
When the device is assembled, the mounting position of the motor unit 101 is set by adjusting the position of the mounting hole 115 with respect to the screw 114, whereby the output shaft 104 and the drive shaft 10 are set.
The distance between the shaft and the shaft 9 is adjusted, and the tension of the belt 113 is set. However, at this time, the tension of the belt 113 may be too high because the tension of the belt 113 may only be set by intuition. In this case, the tension of the belt 113 may be too high. There is a problem that the drive shaft 109 of FIG. As a result, the driven portion 112
Drive accuracy is reduced, and in some cases the drive shaft 109
111 and the driven part 11 fixed to the end of the
This may be an inconvenience because it may interfere with the connection with 2.

[0007]

According to a first aspect of the present invention, there is provided a drive device for an image forming apparatus including a motor unit, a drive shaft unit, a connecting mechanism, and a fixing mechanism. The motor unit supports an output shaft that coaxially fixes the drive pulley and a motor that applies a rotational driving force to the output shaft. The drive shaft unit rotatably supports a drive shaft that coaxially fixes a coupling that is coupled to a driven portion on the image forming apparatus body side and a driven pulley, and is fixed to the image forming apparatus body side. The connection mechanism has a positional relationship that allows the belt to be wound between the drive pulley and the driven pulley, and connects the motor unit and the drive shaft unit so that the axial distance between the output shaft and the drive shaft can be varied. The fixing mechanism fixes the motor unit and the drive shaft unit. Such a drive is
The motor unit and the drive shaft unit are fixed by the fixing mechanism in a state where the tension of the belt wound between the drive pulley and the driven pulley is optimized, and the drive shaft unit is fixed to the image forming apparatus main body side. When fixing the motor unit and the drive shaft unit, if the drive shaft unit is fixed to the jig, the shaft tilt of the drive shaft caused by the increase of the belt tension can be easily detected. You can do it accurately without relying on your intuition. Therefore, the drive shaft can be accurately attached to the image forming apparatus without tilting.

According to a second aspect of the present invention, in the drive unit of the image forming apparatus according to the first aspect, the connecting mechanism is formed by a structure for rotatably connecting the motor unit and the drive shaft unit. Therefore, if the motor unit and the drive shaft unit are rotated in the direction in which the output shaft and the drive shaft are separated from each other while the belt is stretched between the drive pulley and the driven pulley, the belt tension can be easily set. Done.

According to a third aspect of the present invention, in the drive unit for the image forming apparatus according to the first or second aspect, a force is applied to the motor unit to drive the drive unit and the driven pulley away from each other to apply tension to the belt. Further provided is a biasing portion added to the shaft unit. Therefore, the optimum tension is automatically set on the belt stretched between the drive pulley and the driven pulley by the urging force of the urging portion. As a result, the tension of the belt is always maintained at a constant optimum state without requiring special work.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. Further, the same parts as those described with reference to FIG. 5 are designated by the same reference numerals, and the description thereof will be omitted.

Driving device 1 for image forming apparatus according to the present embodiment
Is formed by connecting two units, a motor unit 2 and a drive shaft unit 3, by a connecting mechanism 4 and fixing them by a fixing mechanism 5. And
The driving device 1 is entirely fixed to a main frame 6 on the image forming apparatus main body side (not shown) and is driven by a driven portion 7 on the image forming apparatus main body side, for example, the photosensitive drum 162 in the image forming process portion 155 illustrated in FIG. And paper transport mechanism 1
This is a structure for driving the drive roller 157 and the like in 60.

In the motor unit 2, a motor 9 and an output shaft 10 are attached to a unit frame 8 bent in a U-shape, and a reduction gear train 11 for connecting a rotary shaft 9a of the motor 9 and the output shaft 10 is provided. It is provided and formed. A drive pulley 12 is coaxially fixed to the output shaft 10. In the unit frame 8, both ends bent into a U-shape form a flange 13, and the flange 13 is screwed to the main frame 6 on the image forming apparatus main body side with a screw 14.

The drive shaft unit 3 is formed by rotatably mounting a drive shaft 16 in a cylindrical housing 15 in the same axial direction. More specifically, the drive shaft 16
Is a bearing 17 fixed to one end of the housing 15.
It is supported by a and a bearing 17b fixed to a cap 18 that closes the other end of the housing 15. The two bearings 17a and 17b are both radial type bearings. The driven pulley 19 is coaxially fixed to the drive shaft 16 between the two bearings 17a and 17b, and the coupling 20 is coaxially fixed to the outer side of the one bearing 17a. There is. Further, the housing 15 has one bearing 17a.
A flange 21 is provided at the end on the fixed side.
Is fastened to the main frame 6 on the image forming apparatus main body side with a screw 22.

The connection mechanism 4 is a mechanism for rotatably connecting the motor unit 2 and the drive shaft unit 3. That is, the drive shaft unit 3 is integrally formed with a connecting piece 23 extending in a direction orthogonal to the axial direction of the drive shaft unit 3. A pin 24 is erected on the connecting piece 23 and a fixing screw 25 is screwed therein. ing. The unit frame 8 of the motor unit 2 is formed with a pin hole 26 into which the pin 24 of the drive shaft unit 3 is inserted, and a fixing screw hole 27 into which the fixing screw 25 of the drive shaft unit 3 is inserted. The fixing screw hole 27 is an elongated hole formed on the movement locus of the fixing screw 25 when the motor unit 2 and the drive shaft unit 3 relatively rotate about the pin 24 and the pin hole 26. Here, in each part, the output shaft 10 of the motor unit 2 and the drive shaft 16 of the drive shaft unit 3 are caused by the relative rotation of the motor unit 2 and the drive shaft unit 3 around the pin 24 and the pin hole 26. The positional relationship is such that and are separated from each other. Further, each part includes a drive pulley 12 fixed to the output shaft 10 of the motor unit 2 and a driven pulley 1 fixed to the drive shaft 16 of the drive shaft unit 3.
The belt 28 is set in such a positional relationship that the belt 28 can be stretched over the belt 9. In this case, a belt hole 29 for inserting the belt 28 is formed in the housing 15 of the drive shaft unit 3.

The fixing mechanism 5 is a mechanism for fixing the motor unit 2 and the drive shaft unit 3 to each other, and is a component of the connection mechanism 4, and the fixing screw 25 provided on the connecting piece 23 of the drive shaft unit 3 and the motor unit. 2 and the fixing screw hole 27 provided in the second.

Further, between the motor unit 2 and the drive shaft unit 3, a urging portion for urging the two units 2 and 3 in a direction of increasing the axial distance between the output shaft 10 and the drive shaft 16 is provided. A coil spring 30 is provided. The extension force of the coil spring 30 causes an optimum tension to be generated in the belt 28 stretched between the drive pulley 12 and the driven pulley 19 as the axial distance between the output shaft 10 and the drive shaft 16 increases. It is set to stretch.
The "optimum tension" is not so weak that the belt 28 slips with respect to the drive pulley 12 and the driven pulley 19 and is not so strong that the drive shaft 16 that fixes the driven pulley 19 is tilted. It is a tension.

In such a structure, when the fixing screw 25 which is the fixing mechanism 5 is loosened, the extension force of the coil spring 30 imparts a rotational force to the motor unit 2 and the drive shaft unit 3 to output the output shaft 10. And drive shaft 16
The inter-axis distance between the drive pulley 12 and the driven pulley 19 is increased, and an optimum tension is generated in the belt 28 stretched between the drive pulley 12 and the driven pulley 19. If you tighten the fixing screw 25 in this state,
The motor unit 2 and the drive shaft unit 3 are fixed in a state where the optimum tension is maintained on the belt 28, and the drive device 1 is configured as one unit. Therefore, by fixing such a driving device 1 to the main frame 6 and connecting and coupling the driven part 7 to the coupling 20 of the drive shaft 16, the driven part 7 is driven by the driving device 1. That is, the flange 13 of the motor unit 2 is attached to the screw 1
4 to the main frame 6 with screws, drive shaft unit 3
The drive device 1 is fixed to the main frame 6 by screwing the flange 21 of the above to the main frame 6 with the screw 22. Then, the rotation of the motor 9 is decelerated by the reduction gear train 11 and transmitted to the drive pulley 12, and from the drive pulley 12 to the driven pulley 19 via the belt 28, the drive shaft 16 rotates, whereby. The rotational driving force is transmitted to the driven part 7. At this time, since the tension of the belt 28 is set to the optimum state, the belt 28 does not slip with respect to the drive pulley 12 and the driven pulley 19,
Moreover, the drive shaft 16 for fixing the driven pulley 19 does not tilt. Therefore, the driven portion 7 is driven with high accuracy. Moreover, since the drive shaft 16 does not tilt,
The driven part 7 is smoothly connected and coupled to the coupling 20.

Here, in this embodiment, the tension of the belt 28 is automatically set only by loosening the fixing screw 25 by the extension force of the coil spring 30. Therefore, no special work is required for setting the tension of the belt 28, and the assembly of the device is facilitated. However, in practice, the coil spring 30 does not necessarily have to be provided. When the coil spring 30 is not provided, with the drive shaft unit 3 fixed to the jig,
The axial distance between the output shaft 10 and the drive shaft 16 is adjusted, and the tension of the belt 28 is set. In this case, since the drive shaft unit 3 is fixed to the jig, whether or not the drive shaft 16 is tilted can be easily found by measurement, and the tension of the belt 28 can be set easily and accurately. Become.

In carrying out the invention, the biasing portion is not limited to the coil spring 30, but may be a leaf spring, an elastic member or the like as long as it can generate a biasing force.

[0020]

According to the first aspect of the present invention, a motor unit including a motor and an output shaft driven by the motor, and a drive shaft connected and coupled to a driven portion are fixed to the main body of the image forming apparatus. Since a drive shaft unit is provided, and the motor unit and the drive shaft unit are connected by a connecting mechanism and fixed by a fixing mechanism, a drive pulley fixed to the output shaft and a driven pulley fixed to the drive shaft are provided. If the drive shaft unit is fixed to the jig when setting the tension of the belt that is stretched between the belt tension, it is possible to easily find the tilt of the drive shaft caused by the increase of the belt tension. It can be done accurately without relying on intuition. Therefore, the drive shaft can be accurately attached to the image forming apparatus without tilting.

According to the second aspect of the present invention, since the connecting mechanism is formed by the structure in which the motor unit and the drive shaft unit are rotatably connected, the belt is stretched between the drive pulley and the driven pulley. The belt tension can be easily set only by rotating the motor unit and the drive shaft unit in the direction in which the output shaft and the drive shaft are separated from each other, and the work therefor is simplified.

The invention according to claim 3 further comprises an urging portion for applying a force in a direction for applying tension to the belt by separating the driving pulley and the driven pulley from each other, and therefore the urging portion is urged. The optimum tension of the belt can be automatically set by the urging force of the section, and therefore, the tension of the belt can be always maintained in a constant optimum state without requiring special work.

[Brief description of drawings]

FIG. 1 is a front view in which a part (housing portion) of a drive device according to an embodiment of the present invention is cut away.

FIG. 2 is a longitudinal sectional side view thereof.

FIG. 3 is a front view showing an example of a conventional drive device.

FIG. 4 is a vertical sectional side view thereof.

FIG. 5 is a vertical cross-sectional front view showing an example of a conventional color image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive device 2 Motor unit 3 Drive shaft unit 4 Connection mechanism 5 Fixing mechanism 7 Driven part 9 Motor 10 Output shaft 12 Drive pulley 16 Drive shaft 19 Driven pulley 20 Coupling 28 Belt 30 Energizing part

Claims (3)

[Claims] 1. A motor unit that supports an output shaft that coaxially fixes a drive pulley, a motor that applies a rotational driving force to the output shaft, and a coupling that is coupled to a driven portion on the image forming apparatus main body side. A drive shaft that coaxially fixes a driven pulley is rotatably supported, and a belt can be wound between the drive shaft unit fixed to the image forming apparatus main body side and the drive pulley and the driven pulley. And a connection mechanism for connecting the motor unit and the drive shaft unit such that the inter-axis distance between the output shaft and the drive shaft is variable, and the motor unit and the drive shaft unit are fixed. A drive mechanism for an image forming apparatus, comprising: a fixing mechanism. 2. The drive device for an image forming apparatus according to claim 1, wherein the connecting mechanism is formed by a structure for rotatably connecting the motor unit and the drive shaft unit. 3. The urging part for applying a force in a direction for applying tension to the belt by separating the drive pulley and the driven pulley from each other, further comprising a biasing portion for applying a force to the motor unit and the drive shaft unit. A driving device of the image forming apparatus described in the above.