JPH05297477A - Optical system driving device - Google Patents

Abstract

PURPOSE:To accomplish an optical system driving device capable of surely preventing the backlash of a light source lamp unit and improving reading accuracy in the case of applying this device to an image forming device for a copying machine etc., by having an easy and simple device constitution. CONSTITUTION:As to the optical system driving device provided with a traveling body 70 having a 1st pinion 71 engaged with a fixed rack gear 50 and a 2nd pinion engaged with a movable rack gear, and also where the 1st pinion 71 and the 2nd pinion 72 are coaxially supported by a rotary shaft 73, and also having such a constitution that a light source unit 20 is assembled with the traveling body 70, cushion material 80 is arranged in between the fixed rack gear 50 and a frame for supporting the rack gear 50. The spring performance of the cushion material 80 is given so as to eliminate the backlash lying between the 1st pinion 71 and the fixed rack gear 60, and also to push the part of the traveling body 70 upward. Thus, a sliding member 91 installed on the other end part of the traveling body 70 is pushed against the traveling surface of a traveling rail 90, thus, the traveling body 70 and the light source unit 20 can be smoothly moved in an up-and-down direction and a front-and-back direction without causing the backlash.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system driving device used in a scanner of an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art As a conventional example of an optical system driving device of this type, there is one proposed by the applicant of the present application in Japanese Patent Application No. 3-272923. This optical system driving device will be described below with reference to FIGS.
Follow the instructions below. However, FIGS. 1 and 2 are drawings showing an optical system driving device of the present invention described later.

This optical system driving device is used, for example, in a scanner of a fixed platen type copying machine. Below the document table 10, a light source unit 20 for scanning the document on the document table 10 is provided.
Is provided. The light source unit 20 has a movable base 21 that is movable over the entire length in the scanning direction.
A lamp 22, a reflector 23, a first mirror 24, and the like are mounted on the movable base 21.

The light emitted from the lamp 22 is emitted from the document table 1
The document above 0 is illuminated. The reflected light from the document is guided to the movable mirror unit 31 via the first mirror 24. The mirror unit 31 includes a second mirror 32 and a third mirror 32.
A mirror 33 is mounted, and the reflected light guided to the mirror unit 31 is converted to an opposite optical path by the second mirror 32 and the third mirror 33 and guided to the position of the mirror holder 40 through the lens 34. ..

A fourth mirror 41 and a fifth mirror 42 are mounted on the mirror holder 40. The fourth mirror 41 and the fifth mirror 42 convert the optical path of the guided reflected light in the opposite direction and guide it to the sixth mirror 43 fixedly arranged in the copying machine. The sixth mirror 43 converts the optical path of this reflected light downward, and exposes it on a photosensitive drum (not shown). A known image forming process is performed below.

The mirror unit 31 is a light source unit 20.
Is located at one end of the moving path and is located at the center of the moving path, and the moving range is from the center to the other end of the moving path. The mirror unit 31 is synchronously driven at a speed of 1/2 in the moving direction of the light source unit 20 by an optical system driving device described below.

The optical system driving device is provided below the moving path of the light source unit 20 over the entire length of the moving path, and above the fixed rack gear 50 in parallel with the fixed rack gear 50. A movable rack gear 60 that is movable in the longitudinal direction and a traveling body 70 that is self-propelled along the fixed rack gear 50 and that drives the light source unit 20 and the movable rack gear 60 are provided.

The traveling body 70 is attached to the lower surface of the movable base 21 of the light source unit 20. The traveling body 70
Is a first pinion 71 and a second pinion 7 that mesh with the fixed rack gear 50 and the movable rack gear 60, respectively.
Have two. As shown in FIG. 2, the first pinion 71 and the second pinion 72 are coaxially supported by the same rotary shaft 73.

The rotating shaft 73 of the traveling body 70 is
Is rotated in both forward and reverse directions by a motor (not shown) mounted on the first pinion 71 and the second pinion 72.
Is rotated in directions a and b shown in FIG. When the first pinion 71 rotates in the direction of the arrow a, the rack formed by the first pinion 71 and the fixed rack gear 50.
The traveling body 70 is fixed to the fixed rack gear 50 by the pinion mechanism.
The light source unit 20 supported by the movable base 21 is moved in the scanning direction indicated by the arrow A.

In addition, a pair of front and rear traveling rails 90 are provided at both longitudinal end portions (longitudinal end portions) of the traveling body 70.
Sliding members 91, 91 that slide on 90 are provided. These sliding members 91, 91 reduce the running resistance of the running body 70 and allow the running body 70 to move smoothly. Further, stopper springs 92, 92 are disposed at both ends of the traveling body 70 in the front-rear direction so as to sandwich the traveling surfaces of the L-shaped traveling rails 90, 90 so as to face the sliding members 91, 91.

With the above-mentioned structure, in the above-mentioned conventional apparatus, the traveling rail 90 is sandwiched between the sliding member 91 and the stopper spring 92, so that the traveling body 70 is provided.
Further, the light source unit 20 connected thereto is moved in the vertical direction without play.

[0012]

By the way, in the case of the gear mechanism as described above, the backlash generated between the fixed rack gear 50 and the large diameter first pinion 71 meshing with the fixed rack gear 50 is eliminated. Due to the running body 7
There is a drawback that 0 is loose in the vertical direction and the front-back direction. Particularly, the light source unit 2 assembled to the traveling body 70
When 0 is rattling, the reading accuracy of the original image is deteriorated.

The present invention solves the above-mentioned drawbacks of the prior art. When the present invention is applied to an image forming apparatus such as a copying machine, the light source lamp unit can be reliably prevented from rattling with a simple apparatus configuration. It is an object of the present invention to provide an optical system driving device capable of improving reading accuracy.

[0014]

In the optical system driving device of the present invention, the light source unit is reciprocally moved, and the mirror unit provided in the optical path between the light source unit and the photosensitive member is moved in the moving direction of the light source unit. An optical system driving device for moving at a predetermined speed ratio to a fixed rack gear arranged along the moving path of the light source unit, and a longitudinal direction for moving the mirror unit provided along the fixed rack gear. The movable rack gear movable in the direction, a cushion material provided between the fixed rack gear and the main body frame, a first gear directly meshing with the fixed rack gear, and the movable rack gear directly or indirectly Second to mesh
And the first gear and the second gear are integrally attached to a rotary shaft, and the light source unit is moved by self-propelled along the fixed rack gear by rotation of the rotary shaft. , The diameter ratio of the pitch circles of the first gear and the second gear is set in association with the speed ratio of the light source unit and the mirror unit, and on the longitudinal ends of the traveling body. And a traveling rail that supports the provided sliding member, thereby achieving the above object.

Preferably, the cushion material has a thickness of 1 m.
m neoprene rubber is used.

Preferably, a cushion material is also provided between the movable rack gear and the main body frame.

[0017]

The operation in the case where the cushion material is provided between the fixed rack gear and the main body frame will be described with reference to FIG. In FIG. 3, a sliding member 91 (only one side is shown) that moves on the traveling rail 90 is provided at both front and rear ends of the traveling body 70 that is integrally movable with the light source unit 20. The large diameter first pinion 71 and the small diameter second pinion 72 are connected.

A fixed rack gear 50 is provided on the main body frame (not shown) with the cushion material 80 sandwiched between the fixed rack gear 50 and the tooth surface of the fixed rack gear 50.
It meshes with 1. Therefore, when the first pinion 71 rotates, the traveling body 70 moves on the traveling rail 90 in the front and back direction of the drawing by the rack and pinion mechanism including the first pinion 71 and the fixed rack gear 50.

Reference numeral 93 in the drawing denotes a mirror slide bearing for smoothly guiding the movement of the mirror unit 31 (see FIG. 1) which is integrally moved with the traveling body 70. That is, the guide shaft 94 provided on the mirror unit 31 is inserted into the mirror slide bearing 93.
The mirror unit 31 is smoothly moved by being guided by.

In the above structure, the fixed rack gear 50
When the cushion material 80 is provided between the main body frame 81 and the main body frame 81, the cushion material 80 exerts a spring property and urges the fixed rack gear 50 upward. Along with this, the backlash existing between the fixed rack gear 50 and the first pinion 71 is eliminated, and the first pinion 71, the second pinion 72, and the like are rotated around the center O of the mirror slide bearing 93 as an arrow. It is rotated upward as indicated by F1. As a result, a downward force indicated by arrow F2 acts on the sliding member 91 at the opposite end of the traveling body 70, and the sliding member 91 is pressed against the traveling surface of the traveling rail 90.

Therefore, according to this structure, the traveling body 70 can be smoothly moved in a stable posture without rattling in the up-down direction and the front-rear direction, so that the light source unit 20 is rattled during the movement. There is nothing to do.

The cushion material 80 is a fixed rack gear 50.
It is not limited to between the main frame 81 and the main body frame 81, and may be provided between the movable rack gear 60 and a frame (not shown). If the cushion material 80 is provided at this position as well,
Since the backlash existing between the second pinion 72 and the movable rack gear 60 is eliminated, there is an advantage that the traveling body 70 and the light source unit 20 can be moved more smoothly.

[0023]

EXAMPLES Examples of the present invention will be described below.

The optical system driving device of the present invention is used, for example, in a scanner of a fixed platen type copying machine.

The scanner is, as shown in FIG.
There is provided a light source unit 20 below 0 for scanning the document on the document table 10. The light source unit 20 has a movable base 21 that is movable over the entire length in the scanning direction. The movable base 21 includes a lamp 22 and a reflector 23.
Further, the first mirror 24 and the like are mounted.

The light emitted from the lamp 22 is emitted from the document table 1
The document above 0 is illuminated. The reflected light from the document is guided to the movable mirror unit 31 via the first mirror 24. The mirror unit 31 includes a second mirror 32 and a third mirror 32.
A mirror 33 is mounted, and the reflected light guided to the mirror unit 31 is converted in the reverse optical path by the second mirror 32 and the third mirror 33, and the fixed focus type lens 3
4 to the position of the mirror holder 40.

A fourth mirror 41 and a fifth mirror 42 are mounted on the mirror holder 40. The fourth mirror 41 and the fifth mirror 42 convert the optical path of the guided reflected light in the opposite direction and guide it to the sixth mirror 43 fixedly arranged in the copying machine. The sixth mirror 43 converts the optical path of this reflected light downward and exposes it on the photosensitive drum 100 (see FIG. 5).
A known image forming process is performed below.

The mirror unit 31 is the light source unit 20.
Is located at one end of the moving path and is located at the center of the moving path, and the moving range is from the center to the other end of the moving path. The mirror unit 31 is synchronously driven at a speed of 1/2 in the moving direction of the light source unit 20 by an optical system driving device described below.

The optical system driving device is provided below the moving path of the light source unit 20 over the entire length of the moving path, and above the fixed rack gear 50 in parallel with the fixed rack gear 50. A movable rack gear 60 that is movable in the longitudinal direction, and a traveling body 70 that runs along the fixed rack gear 50 and drives the light source unit 20 and the movable rack gear 60 are provided.

As shown in FIG. 2, the fixed rack gear 50 has elongated holes 51 at both ends thereof, and a screw 52 is passed through the elongated holes 51 and screwed into the screw holes of the frame of the copying machine main body. It is attached with the tooth side facing up. Then, by using the long hole 51, the mounting position of the fixed rack gear 50 in the longitudinal direction with respect to the frame can be finely adjusted.

The movable rack gear 60 is the fixed rack gear 5
It is supported near 0 with the tooth side facing up. The length of the movable rack gear 60 is approximately half the length of the fixed rack gear 50, and the movable rack gear 60 is reciprocated along the fixed rack gear 50. One end of the movable rack gear 60 has the mirror unit 3
It is connected to 1.

The traveling body 70 is attached to the lower surface of the movable base 21 of the light source unit 20. The traveling body 70
Is a first pinion 71 and a second pinion 7 that mesh with the fixed rack gear 50 and the movable rack gear 60, respectively.
Have two. As shown in FIG. 2, the first pinion 71 and the second pinion 72 are coaxially supported by the same rotary shaft 73. The first pinion 71 has a larger diameter than the second pinion 72, and the diameter ratio of the pitch circle thereof corresponds to the speed ratio of the light source unit 20 and the mirror unit 2: 2:
It is set to 1. This diameter ratio is realized by setting the number of teeth of both gears to 2: 1 in this embodiment.

The rotating shaft 73 of the traveling body 70 is
Is rotated in both forward and reverse directions by a motor (not shown) mounted on the first pinion 71 and the second pinion 72.
Is rotated in directions a and b shown in FIG. When the first pinion 71 rotates in the direction of the arrow a, the rack formed by the first pinion 71 and the fixed rack gear 50.
The traveling body 70 is fixed to the fixed rack gear 50 by the pinion mechanism.
The light source unit 20 supported by the movable base 21 is moved in the scanning direction indicated by the arrow A.

When the light source unit 20 is located at the scan start position, the mirror unit 31 of the movable rack gear 60 is provided.
The other end on the side opposite to the connecting position meshes with the second pinion 72.

According to the optical system driving device of the present invention having such a mechanism, the light source unit 20 and the mirror unit 31 are synchronously driven as follows.

When the light source unit 20 is located at the scan start position, the mirror unit 31 is located at the center of its moving path. When the first pinion 71 and the second pinion 72 are rotated in the direction of arrow a from this state and scanning is started, the first pinion 71 meshes with the fixed rack gear 50 and the fixed rack gear 50 is fixed. When the pinion 71 makes one rotation in the a direction, the traveling body 70 moves in the arrow A direction by the pitch circumference of the first pinion 71. The movable rack gear 60 is the second pinion 72.
Since it is connected to the traveling body 70 via the
Along with this, it moves by an amount corresponding to the direction of arrow A, but at this time, since the second pinion 72 is also rotated in the direction of arrow a, the rack and pinion constituted by the second pinion 72 and the movable rack gear 60. The mechanism moves the movable rack gear 60 also in the direction of arrow B, which is the opposite direction to the scanning direction.

Since the diameter of the pitch circle of the second pinion 72 is 1/2 the diameter of the pitch circle of the first pinion 71, the amount of movement of the movable rack gear 60 in the direction of arrow B is the amount of movement in the direction of arrow A. It becomes 1/2 of. Therefore, arrows A and B
In the end, due to the difference in the amount of movement in the direction, the movable rack gear 60
Will be moved in the scanning direction by a half of the moving amount of the traveling body 70. Since the mirror unit 31 is connected to the other end of the movable rack gear 60, according to the above configuration, the mirror unit 31 is moved in the moving direction of the light source unit 20 at a speed ratio of 1/2 of the moving speed of the light source unit 20. You can move in sync with. Therefore, the optical path length can be maintained constant regardless of the movement position of the light source unit 20 during scanning.

When the light source unit 20 reaches the other end of its moving path, that is, the scan end position, the mirror unit 3
1 is also located at the other end of the moving path, and the first pinion 71 and the second pinion 72 are rotated in the arrow b direction. As a result, the light source unit 20 moves in the direction of arrow B, and the mirror unit 31 moves at a speed of 1/2 in the moving direction. Therefore, when the light source unit 20 returns to the scan start position, the mirror unit 31 returns to the center of the moving path shown in FIG.

In addition to the above configuration, in the optical system driving device of the present invention, the fixed rack gear 50 and the main body frame 81.
Cushion members 80 are provided between the movable rack gear 60 and a frame (not shown). The lengths of the cushion members 80, 80 substantially correspond to the lengths of the fixed rack gear 50 and the movable rack gear 60, respectively.

When the cushion material 80 is provided between the fixed rack gear 50 and the main body frame 81 in this way, the traveling body 70 and the light source unit 20 assembled to the traveling body 70 can be smoothly moved in the vertical direction and the front-back direction without rattling. Can be done. The reason for this is shown in FIGS. 3 and 4 below.
Follow the instructions below.

As shown in FIGS. 3 and 4, a sliding member 91 that moves on the traveling rail 90 is provided at both ends in the front-rear direction of the traveling body 70 that can move integrally with the light source unit 20.
(Both are shown on one side only). Further, the mirror unit 31 is provided with a mirror slide bearing 93 that smoothly guides its movement. That is, the mirror slide bearing 93 includes the mirror unit 31.
A guide shaft 94 provided in the mirror unit 31 is inserted therein, and the mirror unit 31 is smoothly moved by being guided by the guide shaft 94.

In such a structure, the cushion material 8
0 exerts a spring property and urges the fixed rack gear 50 upward. Along with this, the backlash existing between the fixed rack gear 50 and the first pinion 71 is eliminated, and the first pinion 71, the second pinion 72, and the like are rotated around the center O of the mirror slide bearing 93 as an arrow. It is rotated upward as indicated by F1. As a result, a downward force indicated by the arrow F2 acts on the sliding member 91 at the opposite end of the traveling body 70, and the sliding member 91 is pressed against the traveling surface of the traveling rail 90.

Therefore, according to the above configuration, the traveling body 70 can be smoothly moved in a stable posture without rattling in the up-down direction and the front-rear direction, and thus rattling occurs in the light source unit 20 during the movement. Never. Therefore, there is an advantage that the reading accuracy of the original image can be improved. Moreover, since it is sufficient to provide the cushion material 80, the device configuration does not become complicated and large, and the cost does not increase.

In the present embodiment, the movable rack gear 60
A cushion material 80 is also provided between the frame and a frame (not shown). If the cushion member 80 is provided also in this position, the backlash existing between the second pinion 72 and the movable rack gear 60 is eliminated, so that there is an advantage that the traveling body 70 and the light source unit 20 can be moved more smoothly. is there.

The material of the cushion member 80 as described above is preferably neoprene rubber, and the thickness thereof is preferably 1.0 mm. That is, as the cushion material 80, a urethane rubber having a thickness of 1.0 mm, a neoprene rubber having a thickness of 1.0 mm and a neoprene rubber having a thickness of 1.5 mm were used. It was confirmed that the backlash can be reliably eliminated by using the cushion material 80 made of neoprene rubber of 0.0 mm.

5 and 6 show another embodiment of the present invention. In this embodiment, the fourth mirror 41 and the fifth mirror 42
Further, without providing the mirror holder 40 supporting them, the reflected light from the second mirror 41 ′ corresponding to the fourth mirror 41 and the third mirror 42 ′ corresponding to the fifth mirror 42 is reflected by the sixth mirror 43. Of the fourth mirror 43 'corresponding to the above. Also, in this embodiment, unlike the above-described embodiment, the fixed rack gear 50 that meshes with the first pinion 71 is attached to the upper side, and the movable rack gear 60 that meshes with the second pinion 72 is provided below. Further, the second pinion 72 and the movable rack gear 60 are meshed with each other via an idle gear 74. Reference numeral 76 is a rotating shaft of the idle gear 74. Further, the optical system drive device is provided with a drive gear 75 that meshes with the movable rack gear 60.

The fixed rack gear 50 is provided with elongated holes 111 at both ends in the longitudinal direction so that the position of the fixed rack gear 50 can be adjusted in the moving direction of the traveling body 70.
The frame 110 on which 111 is formed is fixed by screws 52, 52. In the above configuration,
The gear ratio between the first pinion 71 and the second pinion 72 is
The gear ratio between the first pinion 71 and the idle gear 74 is 2: 1, and the gear ratio between the second pinion 71 and the idle gear 74 is 1: 1.

In such a structure, the light source unit 2
The movement of 0 and the traveling body 70 is performed as follows. When the first pinion 71 makes one rotation in the arrow C direction, the rotation shaft 73 of the first pinion 71 moves in the A direction by the pitch circumference. If the first pinion 71 is the module 1 and the number of teeth is 36, when the first pinion 71 makes one rotation, the rotation 74 rotates in the A direction by 36π.

Next, the second gear meshing with the idle gear 74
The pinion 72 also makes one rotation by one rotation of the first pinion 71, but since the gear ratio of both is 2: 1, the number of teeth of the second pinion 72 is 18. Therefore, the pitch circle moving distance is 18π. Therefore, the idle gear 74 rotates in the direction of arrow D for the pitch circle moving distance of 18π, and transmits this to the movable rack gear 60.
As a result, the movable rack gear 60 moves to the first pinion 7
Rotational shafts 73 and 76 of the first and second pinion 72 and the idle gear 74, that is, the moving distance 36π of the light source unit 20 in the A direction, and the idle gear 7 that is returned in the opposite direction.
4 will be moved in the A direction by 18π which is the difference from the moving distance of 18 in the B direction of 18π. Therefore, according to the above configuration, with respect to the moving speed v of the light source unit 20, the movable rack gear 60 has v × 18π / 36π, that is, v / 2.
It moves in the same direction as the light source unit 20 at the speed of.

Also in this embodiment, the fixed rack gear 5 is used.
0 and the movable rack gear 60 are supported by the frame via the cushion members 80, 80 similar to the above. Therefore, also in the case of this embodiment, the traveling body 7 is the same as the above embodiment.
The movement of the light source unit 20 and the light source unit 20 can be smoothly performed in the up and down direction and the back and forth direction without rattling. The parts corresponding to those in the above-described embodiment are designated by the same reference numerals, and the detailed description will be omitted.

Although the whole of the illustrated embodiment is as described above, the present invention can be variously modified. For example, the mounting form of the movable rack gear 60 and the fixed rack gear 50 is not limited to the form of the above-described embodiment, and may be screwed through a round hole, for example.

[0052]

According to the optical system driving device of the first aspect, since the cushion material is provided between the fixed rack gear and the main body frame, the fixed rack gear is attached due to the spring property exhibited by the cushion material. Since the backlash existing between the fixed rack gear and the first pinion meshed with the fixed rack gear is eliminated and the other end of the traveling body is pressed against the traveling surface, the traveling body and the light source unit assembled to the traveling body are eliminated. Can be smoothly moved in the up and down direction and the back and forth direction.

Therefore, when such an optical system driving device is applied to an image forming apparatus such as a copying machine, there is an advantage that the reading accuracy can be improved. Moreover, since it is only necessary to provide the cushioning material, the apparatus configuration is not complicated, the size is large, and the cost is not increased.

In particular, according to the optical system driving device of the third aspect, there is an advantage that the traveling body and the light source unit can be moved more smoothly.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a copying machine to which an optical system driving device of the present invention is applied.

FIG. 2 is an exploded perspective view showing a rack and pinion mechanism that constitutes the optical system driving device of the present invention.

FIG. 3 is a front view showing a traveling body of the optical system driving device of the present invention.

FIG. 4 is a view in the direction of the arrow X in FIG.

FIG. 5 is an exploded perspective view showing a rack and pinion mechanism that constitutes a conventional optical system driving device.

6 is a partial cross-sectional view showing a conventional example of a copying machine to which the optical system driving device shown in FIG. 5 is applied.

FIG. 7 is a front view showing a traveling body of a conventional optical system driving device.

[Explanation of symbols]

 10 Document Plate 20 Light Source Unit 31 Mirror Unit 40 Mirror Holder 50 Fixed Rack Gear 60 Movable Rack Gear 70 Traveling Body 71 First Pinion 72 Second Pinion 73 Rotating Shaft 80 Cushion Material 81 Frame 90 Traveling Rail 91 Sliding Member 93 Mirror Slide Bearing

Claims (3)

[Claims] 1. An optical system driving device for reciprocating a light source unit and moving a mirror unit provided in an optical path between the light source unit and a photoconductor at a predetermined speed ratio in a moving direction of the light source unit. A fixed rack gear arranged along the moving path of the light source unit, a movable rack gear provided along the fixed rack gear and movable in the longitudinal direction to move the mirror unit, and the fixed rack gear. A cushion material provided between the rack gear and the main body frame; a first gear that directly meshes with the fixed rack gear; and a second gear that meshes with the movable rack gear directly or indirectly. And the second gear are integrally attached to the rotary shaft, and the light source unit is moved by self-propelled along the fixed rack gear by the rotation of the rotary shaft. A traveling body in which a diameter ratio of pitch circles of the first gear and the second gear is set in association with a speed ratio between the light source unit and the mirror unit; An optical system driving device comprising: a traveling rail that supports the provided sliding member. 2. The optical system driving device according to claim 1, wherein the cushion material is neoprene rubber having a thickness of 1 mm. 3. The optical system driving device according to claim 1, wherein the cushion material is also provided between the movable rack gear and the main body frame.