JP3742519B2 - Gear transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear transmission configured to engage a pinion provided on a drive shaft of a motor with two driven gears rotatably supported at predetermined intervals.
[0002]
[Prior art]
In an image forming machine such as a printer or a copying machine, a photosensitive drum, a developing roller of a developing device, a transporting roller for transporting transfer paper, a fixing roller of a fixing device, and the like are driven to rotate. These photosensitive drums, rollers, and the like are generally configured to be driven via a gear transmission by a driving force of an electric motor. In such a gear transmission, the reaction force when the driven gear is driven by a pinion provided on the drive shaft of the electric motor is balanced, and the drive load is reduced by reducing the gear train to the drive target member. In order to reduce this, a configuration in which a pinion is meshed with two driven gears and a gear train is driven from the two driven gears is generally put into practical use.
[0003]
In the gear transmission described above, the electric motor is mounted on the mounting board after the gear mechanism including the two driven gears is rotatably supported on the board for ease of assembly. At the time of mounting, a pinion provided on the drive shaft of the electric motor is engaged with each of the two driven gears while being inserted through a positioning mounting hole provided on the mounting board.
[0004]
[Problems to be solved by the invention]
Thus, in the above-described conventional gear transmission, the pinion provided on the drive shaft when the electric motor is mounted is disposed between the side surfaces of the two driven gears disposed on the mounting substrate at a predetermined interval. It becomes a form to pry, causing damage to the driven gear, such as scratching.
[0005]
The present invention has been made in view of the above-mentioned facts, and its main technical problem is that the pinion provided on the drive shaft of the motor can be meshed without damaging the two driven gears. Another object of the present invention is to provide a gear transmission capable of securely mounting a motor at a predetermined position.
[0006]
[Means for Solving the Problems]
In order to solve the above technical problem, according to the present invention, a mounting board, two driven gears rotatably supported at a predetermined interval on the mounting board, and the two driven gears A gear transmission comprising a motor having a drive shaft with a pinion meshing with each gear;
The mounting board has a circular mounting hole formed around a midpoint between the two driven gears on a line connecting the shaft centers of the two driven gears, and the two driven gears. A guide groove which is formed perpendicular to the line connecting the shaft cores and continuous with the mounting hole and has a width smaller than the diameter of the mounting hole and larger than the diameter of the pinion,
The motor is provided with a positioning portion that has a diameter corresponding to the mounting hole on the end surface on the drive shaft side and that fits into the mounting hole.
The gear transmission characterized by this is provided.
[0007]
The guide groove is preferably formed around a line passing through the intermediate point and perpendicular to a line connecting the axis of the two driven gears, and the motor includes the guide groove at the front end of the positioning portion. It is desirable that a guided portion having a diameter corresponding to the guide groove and fitted in the guide groove is provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a gear transmission configured according to the present invention will be described with reference to the accompanying drawings.
[0009]
FIG. 1 is a schematic sectional view of a laser beam printer equipped with a gear transmission constructed according to the present invention.
The illustrated laser beam printer includes a rectangular parallelepiped housing 2 made of synthetic resin. In the substantially central portion of the housing 2, there is a space between a front side plate and a rear side plate made of a metal plate (not shown) arranged in the housing 2 at a predetermined interval in the front-rear direction (a direction perpendicular to the paper surface in FIG. 1). A photosensitive drum 4 is rotatably arranged. The photosensitive drum 4 is driven to rotate in a direction indicated by an arrow 4a by a gear transmission to be described later. Around the photosensitive drum 4 rotated in the direction indicated by the arrow 4a, the charging corona discharger 6, the developing device 8, the transfer roller 10, the peeling corona discharger 12, and the cleaning device 14 are sequentially seen in the direction of the arrow 4a. And the static elimination lamp 16 is arrange | positioned. In the illustrated embodiment, the photosensitive drum 4, the charging corona discharger 6, the cleaning device 14, and the charge eliminating lamp 16 are mounted on one unit frame to constitute a photosensitive unit.
[0010]
The charging corona discharger 6 charges the photosensitive layer mounted on the peripheral surface of the photosensitive drum 4 to a specific polarity. In the illustrated embodiment, the developing device 8 includes a developing housing 81 that contains a developer composed of one-component toner, a developing roller 82 disposed in the developing housing 81, a stirring means 83, and the like, as will be described later. Thus, the electrostatic latent image formed on the peripheral surface of the photosensitive drum 4 is developed into a toner image. A toner cartridge 18 containing replenishing toner is detachably mounted above the developing housing 81 so that the toner is replenished sequentially when a predetermined amount of toner is consumed. The transfer roller 10 is made of, for example, conductive foamed urethane, is rotatably supported by the front and rear side plates, and is driven to rotate in a direction indicated by an arrow by a gear transmission described later. For example, a constant current of about 10 μA is applied to the transfer roller 10. The peeling corona discharger 12 performs corona discharge on the back surface of the recording paper after transfer. The cleaning device 14 includes a cleaning housing 141 and a cleaning fur brush 142 disposed in the cleaning housing 141, a cleaning blade 143, a toner conveying member 144, and the like, and removes toner remaining on the surface of the photosensitive drum 4.
[0011]
A laser unit 20 is disposed in the upper part of the housing 2, that is, above the photosensitive unit. The illustrated laser unit 20 includes a box-shaped unit housing 201. In the housing 201, a laser light source (not shown), a rotating polygon mirror 202 rotated in a predetermined direction, and a first imaging lens are provided. 203, a second imaging lens 204, a first reflecting mirror 205, a second reflecting mirror 206, a third reflecting mirror 207, and a cylindrical lens 208 are provided. A laser light source (not shown) irradiates the rotary polygon mirror 202 with laser light based on image information output from a computer, for example. The laser light reflected from the rotating polygonal mirror 202 passes through the first imaging lens 203 and the second imaging lens 204 to the first reflecting mirror 205 as shown by a broken line in FIG. Are reflected by the reflecting mirror 205, the second reflecting mirror 206, and the third reflecting mirror 207 and then passed through the cylindrical lens 208 to form a projection area formed between the charging corona discharger 6 and the developing device 8. Is projected onto the peripheral surface of the photosensitive drum 4.
[0012]
In the housing 2, a recording paper transport mechanism, which is indicated by the number 22 as a whole from the lower part to the upper left part, is disposed. The illustrated recording paper transport mechanism 22 includes a paper feed roller pair 24, a guide plate 26, a registration roller pair 28, a guide plate 30, a guide plate 32, a fixing roller pair 34 constituting a fixing device, a guide plate 36, a transport roller pair 38, A guide claw 40, a guide plate 42, a conveying roller pair 44, a guide plate 46, and a discharge roller pair 48 are provided. Recording paper cassettes 50 and 50 are connected to the lower side of the housing 2. The recording paper cassette 50 includes a paper feeding unit (not shown), and the recording paper is fed toward the paper feed roller pair 24 by the paper feeding unit. On the other hand, the recording paper sent out by the action of the discharge roller pair 48 is discharged to the receiving portion 2 a defined on the upper surface of the housing 2.
[0013]
Note that the illustrated laser beam printer is configured such that a reversing unit 52 indicated by a two-dot chain line in the drawing can be optionally attached to the lower side of the recording paper transport mechanism 22. The reversing unit 52 is used when recording on both sides of a recording sheet. That is, when recording on both sides of the recording paper, when the image is recorded on the surface of the recording paper, the guide claw 40 is positioned at a position indicated by a two-dot chain line, and the recording paper on which the image is recorded is recorded. Is guided to the reversing unit 52. The recording paper introduced into the reversing unit 52 is transported toward the guide plate 26 with its back surface turned upside down.
[0014]
Here, the operation of the laser beam printer described above will be briefly described.
While the photosensitive drum 4 is rotated in the direction indicated by the arrow 4a, the charging corona discharger 6 charges the photosensitive layer of the photosensitive drum 4 to a specific polarity. Next, laser light from a laser light source (not shown) of the laser unit 20 is projected onto the photosensitive drum 4 in the projection area, and an electrostatic latent image corresponding to image information is formed on the peripheral surface of the photosensitive drum 4. The Thereafter, the developing roller 82 of the developing device 8 causes the toner to act on the electrostatic latent image on the photosensitive drum 4 to develop the electrostatic latent image into a toner image. On the other hand, the recording paper is fed by a paper feeding means (not shown) of the recording paper cassette 50. The recording paper is conveyed by the paper feed roller 24, temporarily stopped by the registration roller pair 28, and conveyed to a transfer area where the photosensitive drum 4 and the transfer roller 10 face each other at a timing with the photosensitive drum 4. The toner image formed on the peripheral surface of the photosensitive drum 4 by the action of the transfer roller 10 is transferred to the recording paper conveyed to the transfer area. The recording paper on which the toner image has been transferred is peeled off from the photosensitive drum 4 by the action of the peeling corona discharger 12, and then conveyed to the fixing roller pair 34. The toner image is transferred to the surface of the recording paper by the action of the fixing roller pair 34. To be established. The recording paper on which the toner image has been fixed is conveyed by the conveying roller pair 38 and 44 and discharged to the receiving portion 2 a on the housing 2 through the discharging roller pair 48. On the other hand, the photosensitive drum 4 continues to rotate, the residual toner is removed from the surface of the photosensitive drum 4 by the action of the cleaning device 14, and the photosensitive layer of the photosensitive drum 4 is discharged by the action of the charge removal lamp 16.
[0015]
Next, a gear transmission for rotationally driving the photosensitive drum 4 and each roller will be described with reference to FIGS.
The gear transmission 60 in the illustrated embodiment is mounted on the back surface of the rear side plate (not shown) described above. The gear transmission 60 includes a mounting substrate 601. A first driven gear 602 and a second driven gear 603 having an electromagnetic clutch are rotatably supported on the mounting substrate 601 at a predetermined interval. Further, on the mounting substrate 601, the respective gears that transmit the driving force of the electric motor described later via the first driven gear 602 and the second driven gear 603 are rotatably supported. . Each gear will be described in accordance with a power transmission path from the first driven gear 602 and the second driven gear 603.
[0016]
The first driven gear 602 meshes with the intermediate gear 605 via the intermediate gear 604 and the electromagnetic clutch. One intermediate gear 604 that meshes with the first driven gear 602 is mounted on the rotation shaft of the transfer roller 10 and drives the transfer roller 10 to rotate. The intermediate gear 604 is meshed with an intermediate gear 606 that meshes with a drum gear (not shown) mounted on the photosensitive drum 4 via an electromagnetic clutch.
[0017]
The other intermediate gear 605 that meshes with the first driven gear 602 is configured as a two-stage gear and meshes with the intermediate gear 607. The intermediate gear 607 meshes with an intermediate gear 608 that meshes with a developing gear (not shown) that transmits power to the developing roller 82 and the agitating unit 83 of the developing device 8. The intermediate gear 607 is meshed with a registration gear 609 for rotationally driving the registration roller pair 28 via a one-way clutch (not shown). Further, the intermediate gear 607 meshes with a paper feed gear 610 for driving the paper feed roller pair 24 via an electromagnetic clutch (not shown).
[0018]
The second driven gear 603 meshes with an intermediate gear 611 constituted by a two-stage gear, and the fixing roller pair 34, the transport roller pairs 38 and 44, and the discharge roller pair via the intermediate gear 612 and the intermediate gear 613. The gear train is connected to a gear train (not shown) for driving 48.
[0019]
An electric motor 70 for driving the first driven gear 602 and the second driven gear 603 is mounted on the mounting substrate 601 from the back. The electric motor 70 is mounted such that a pinion 72 provided on the drive shaft 71 meshes with the first driven gear 602 and the second driven gear 603. In order to facilitate the meshing of the pinion 72 with the first driven gear 602 and the second driven gear 603 when the electric motor 70 is attached to the mounting substrate 601 as a set, the mounting substrate 601 is shown in FIG. Thus, a mounting hole 616 and a guide groove 615 are formed. The mounting hole 616 is formed in a circular shape centering on an intermediate point P between the two gears on a straight line 617 connecting the axial centers of the first driven gear 602 and the second driven gear 603. The guide groove 615 is formed continuously with the mounting hole 616 perpendicular to a straight line 617 connecting the shaft centers of the two gears. The guide groove 615 is formed around a line 618 orthogonal to the straight line 617 passing through the intermediate point P, and its width (B) is smaller than the diameter (D) of the mounting hole 616 and the diameter (d1) of the pinion 72. It is configured larger.
[0020]
On the other hand, the electric motor 70 to be mounted on the mounting substrate 601 is provided with a positioning portion 73 formed to project from the end surface of the case 700 on the drive shaft 71 side. The positioning portion 73 is formed in a columnar shape around the axis of the drive shaft 71 and has a diameter (d2) corresponding to the mounting hole 616. By fitting into the mounting hole 616, the electric motor 70 is positioned. Is positioned at the mounting position. On the front end surface of the positioning portion 73, a guided portion 74 formed to protrude is provided. The guided portion 74 has a diameter (d3) corresponding to the width (B) of the guide groove 615 and is formed in a cylindrical shape with the axis of the drive shaft 71 as the center, and is fitted into the guide groove 615. It can move while being guided along the guide groove 615. A mounting plate 80 for mounting on the mounting substrate 601 is fixed to the drive shaft 71 side of the case 700 of the electric motor 70. The mounting plate 80 is provided with four mounting holes 81.
[0021]
Next, a procedure for mounting the electric motor 70 on the mounting substrate 601 will be described.
First, when the pinion 72 provided on the drive shaft 71 of the electric motor 70 is inserted through the guide groove 615 from the back side of the mounting substrate 601 and the guided portion 74 is fitted into the guide groove 615, the positioning portion 73 is attached to the mounting substrate 601. It touches the back of the. Next, when the electric motor 70 is moved toward the mounting hole 616, the guided portion 74 moves along the guide groove 615. As described above, the guide groove 615 is a line orthogonal to the straight line 617 passing through the intermediate point P between the two gears on the straight line 617 that connects the axial centers of the first driven gear 602 and the second driven gear 603. The pinion 72 is moved between the first driven gear 602 and the second driven gear 603 by the above movement toward the mounting hole 616 of the electric motor 70. To do. Accordingly, the pinion 72 can enter between the first driven gear 602 and the second driven gear 603 and can easily and reliably mesh with both gears. At this time, since the first driven gear 602 and the second driven gear 603 are rotatably supported, when the meshing phase with the pinion 72 is shifted, the phase difference is corrected by rotating. Engage easily. In this way, when the pinion 72 reaches a position where the first driven gear 602 and the second driven gear 603 are engaged with each other, the positioning portion 73 is fitted into the mounting hole 616, and the electric motor 70 is mounted in a predetermined manner. Positioned. When the electric motor 70 is positioned at a predetermined mounting position, the screw 90 is inserted through the mounting hole 81 and screwed into the screw hole 620 formed in the mounting substrate 601, so that the electric motor 70 is mounted on the mounting substrate 601. be able to.
[0022]
The gear transmission configured according to the present invention has been described based on the embodiment applied to the laser beam printer. However, the present invention is not limited to the embodiment, and the gear transmission mounted on various machines. Can be applied to.
[0023]
【The invention's effect】
According to the present invention, the mounting substrate on which the two driven gears are rotatably supported at a predetermined interval is provided between the two driven gears on the line connecting the shaft cores of the two driven gears. Since a circular mounting hole formed around a point and a guide groove formed perpendicular to the line connecting the shaft cores and continuous with the mounting hole are provided, when mounting the motor on the mounting board, By inserting a pinion provided on the drive shaft of the motor through the guide groove and moving toward the mounting hole along the guide groove, the pinion enters between the two driven gears and is easy and reliable with both gears. Can mesh with each other. And it can position to a predetermined mounting position by fitting the positioning part provided in the motor in the mounting hole.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a laser beam printer equipped with a gear transmission constructed according to the present invention.
FIG. 2 is a front view of a gear transmission constructed according to the present invention.
3 is a rear view of the gear transmission shown in FIG. 2. FIG.
4 is a perspective view of an electric motor constituting the gear transmission shown in FIG. 2. FIG.
[Explanation of symbols]
2: Housing 4: Photoconductor drum 6: Charging corona discharger 8: Developing device 10: Transfer roller 12: Peeling corona discharger 14: Cleaning device 16: Static elimination lamp 20: Laser unit 22: Recording paper transport mechanism 24: Paper feed roller pair 28: Registration roller pair 34: Fixing roller pair 60: Gear transmission 601: Mounting substrate 602: First driven gear 603: Second driven gear 616: Mounting hole 617: Guide groove 70: Electric Motor 71: Drive shaft 72: Pinion 73: Positioning part 74: Guided part 80: Mounting plate

Claims (3)

An attachment board, two driven gears rotatably supported on the attachment board at a predetermined interval, and a motor having a drive shaft provided with pinions that mesh with the two driven gears, respectively. In the gear transmission provided,
The mounting board has a circular mounting hole formed around a midpoint between the two driven gears on a line connecting the shaft centers of the two driven gears, and the two driven gears. A guide groove which is formed perpendicular to the line connecting the shaft cores and continuous with the mounting hole and has a width smaller than the diameter of the mounting hole and larger than the diameter of the pinion,
The motor is provided with a positioning portion that has a diameter corresponding to the mounting hole on the end surface on the drive shaft side and that fits into the mounting hole.
A gear transmission characterized by that. The gear transmission according to claim 1, wherein the guide groove is formed around a line passing through the intermediate point and orthogonal to a line connecting the shaft cores of the two driven gears. The gear transmission according to claim 1 or 2, wherein the motor is provided with a guided portion having a diameter corresponding to the guide groove at a front end of the positioning portion and fitted into the guide groove.

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