JPH06282013A - Optical device - Google Patents

Abstract

PURPOSE:To provide an optical device which can be smoothly ran without jumping even when it is accelerated or decelerated without increasing the weight thereof. CONSTITUTION:A first carriage 25 scanning an original G placed on an original platen glass in a prescribed direction while exposing it, guide rails 72 and 73 freely slidably guiding the carriage 25, supporting shafts 68 and 69 supporting the carriage 25 on the rails 72 and 73, contact members 70 and 71 provided at both end parts of the shafts 68 and 69 in a direction in parallel with a scanning direction and brought into contact with the rails 72 and 73, driving belts 76 and 77 fixed at one part of the carriage 25 a driving motor 90 sliding the carriage 25 by driving the belts 76 and 77 in a state where the contact members 70 and 71 of the shafts 68 and 69 are brought into contact with the rails 72 and 73 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device for exposing and scanning an original provided in an electronic copying machine, for example.

[0002]

2. Description of the Related Art Some electronic copying machines expose a document surface by irradiating a document set on a platen glass with light while an optical device is running.

By this exposure scanning, the reflected light reflected from the document surface is guided to the photosensitive drum to form an image, thereby forming a document image.

For example, an optical device as disclosed in Japanese Examined Patent Publication No. 5-2214 has a carriage base that moves in the scanning direction. The carriage base is provided with an exposure lamp and a reflector that guides the light from the exposure lamp to the document surface. Further, the carriage base is provided with a reflection mirror and a cover for reflecting the light reflected from the document surface in a predetermined direction to form an exposure scanning unit. A pair of contact members are attached to both ends of the bottom surface of the carriage base in the direction orthogonal to the scanning direction. The pair of contact members are attached at a predetermined interval along the scanning direction of the carriage base. The carriage base 1 brings the pair of contact members into contact with a guide rail, and the contact members are guided by the guide rail.
The car slides in contact with the car.

However, conventionally, since the pair of contact members of the carriage base are arranged within the width dimension of the carriage base in the traveling direction, the distance between the pair of contact members is small and the center of gravity of the exposure scanning unit is small. It may not be located between the pair of contact members.

For this reason, the stability of the exposure scanning unit during traveling is poor, and the exposure scanning unit jumps up and down during acceleration and deceleration, resulting in large image blurring and noise.

If the width of the carriage base itself is increased, the distance between the pair of contact members can be increased, and the center of gravity of the carriage base can be arranged between the contact members. You can

[0008]

However, in this case, the weight of the carriage base becomes large, the load torque of the motor increases, and this causes malfunction of the carriage motor. Therefore, the width of the carriage base cannot be simply increased.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical device capable of running smoothly without jumping even when accelerated or decelerated without increasing weight.

[0010]

In order to solve the above-mentioned problems, the present invention solves the above-mentioned problems by exposing an original document placed on a document table while exposing the original document in a predetermined direction, and by mounting the exposure scanning means. A guide means for slidably guiding the exposure scanning means and both ends of the exposure scanning means in a direction orthogonal to the scanning direction and having a length longer than a width of the exposure scanning means in the scanning direction. Having and supporting means for supporting the exposure scanning means on the guide means,
By providing contact means provided at both ends of the support means in a direction parallel to the scanning direction and in contact with the guide means, a drive belt fixed to a part of the exposure means, and driving the drive belt. Drive means for sliding the exposure scanning means while the contact means of the supporting means is in contact with the guide means.

Further, a movable exposure scanning means for scanning while exposing a document placed on a document table, a guide means for guiding the movement of the exposure scanning means, and a side which is orthogonal to the scanning direction of the exposure means. Provided at both ends of the rod-shaped member having a length longer than the width of the exposure scanning means in the scanning direction, and provided at both ends of the rod-shaped member parallel to the scanning direction of the exposure scanning means. And a support member for supporting the rod-shaped member on the guide means.

[0012]

By the above means, the center of gravity of the exposure scanning means can be positioned between the contact members, and the stability of the exposure scanning means during traveling can be improved to reliably prevent the exposure scanning means from jumping during acceleration and deceleration. It can be so.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS.

FIG. 1 shows an image forming apparatus.
Reference numeral 1 is a device body.

The apparatus body 11 is mounted on the upper surface of the mounting table 12.

A document table glass 13 on which a document G is placed is provided on the upper surface of the apparatus main body 11, and an operation unit 14 is provided on the front side. The operation unit 14 includes a setting key 18 for setting the number of copies, a selection key 19a for selecting the paper size, a magnification setting key 19b for setting the image magnification, a copy button 17 for starting the copying operation, and the like. Operation key
Is provided.

Further, a manual paper feed section 15 for feeding manual paper is provided on one side surface of the apparatus main body 11, and a paper discharge tray 1 for discharging paper on which an image is formed on the other side surface.
6 is provided.

First to third sheet feeding cassettes 35 to 37 for accommodating sheets are arranged in the table 12 so as to be freely inserted and removed, and a large amount of sheets are provided on one side of the table 12. A large-capacity sheet feeding device 39 for accommodating is provided.

FIG. 2 shows the internal structure of the apparatus main body 11. An optical device 41 is provided on the upper side of the device body 11. On the lower side of the optical device 41, a photosensitive drum 20 as an image bearing member is rotatably provided in the arrow direction. The optical device 41 includes first to second carriages 25, 26, a lens block 46, and fourth to sixth reflection mirrors 47, 48, 49 for guiding the light passing through the lens 46 to the photosensitive drum 20. It is configured. The detailed configuration of the optical device 41 will be described later. A charging charger 21 for uniformly charging the surface of the photoconductor drum 20 is sequentially disposed around the photoconductor drum 20 along the rotation direction thereof, and charges remaining on the surface of the photoconductor drum 20 are erased. Erase array 28, developing device 23 for developing the latent image formed on the surface of the photoconductor drum 20 by exposure
Is provided. Further, a transfer charger 24 for transferring the developer image formed on the surface of the photoconductor drum 20 to a sheet and a developer image are sequentially provided around the photoconductor drum 20 along the rotation direction thereof. A peeling charger 27 that peels the transferred sheet from the photoconductor drum 20, a cleaning device 29 that removes the developer remaining on the photoconductor drum 20, and a charge remaining on the photoconductor drum 20 are removed. A static eliminator 30 is provided.

Reference numeral 31 in the drawing denotes a conveying path for conveying the paper, and the conveying path 31 is sequentially arranged along the conveying direction of the paper.
Registration roller pair 32 for aligning the sheet, the transfer and peeling chargers-24, 27, and a conveyor belt 3 for conveying the sheet.
3, a fixing device 34 for fixing the transfer image transferred to the paper,
A discharge roller 38 and a paper discharge roller 40 that carry out the paper are provided.

The discharging roller 38 and the discharging roller 4 are also provided.
Between 0 and 0, a gate 51 for selectively changing the sheet conveying direction is rotatably provided. By this gate 51, the paper is sent to the paper discharge roller 40 or the conveyance path 52 for the superposition copying.

An accumulating section 53 for accumulating sheets is provided on the lower side of the above-mentioned conveying path 52 for superposition copying, and this accumulating section 5 is provided.
The sheets stacked on the sheet 3 are sent to the aligning roller 32 through the conveying path 54.

The optical device 41 is constructed as shown in FIGS.

As shown in FIG. 4, the optical device 41 includes a platen glass 1 provided on the upper surface of the device body 11.
First and second carriages 2 traveling back and forth along
5, 26 are provided.

The first carriage 25 constitutes an exposure unit as an exposure scanning means, and the first carriage 25 has an exposure lamp 42 for irradiating the original with light and a reflected light reflected from the original in a predetermined direction. A first reflection mirror 43 for reflecting is provided. The second carriage 26 has second and third reflection mirrors that reflect the reflected light from the first reflection mirror 43 in a predetermined direction.
44 and 45 are arranged.

In the optical path of the reflected light reflected from the third reflection mirror 45, as shown in FIG.
Further, fourth to sixth reflection mirrors 47, 48, 49 for guiding the light passing through the lens 46 in a predetermined direction are provided.

As shown in FIG. 4, the first carriage 25 has a carriage base 61, and the carriage base 61 has a reflector 62 and the exposure lamp 42.
Is attached.

Further, an electric component 65 is attached to the carriage base 61 via a mounting member 64, and the electric component 65 is covered by a cover 66.

As shown in FIG. 5, a light amount adjusting member 67 for adjusting the amount of light from the exposure lamp 42 toward the original is attached to the upper surface of the cover 66.

By the way, the carriage base 61 is provided at both ends in a direction orthogonal to the traveling direction of the carriage base 61.
Support shafts 68 and 69 as support means are attached along the traveling direction of the space 61. These support shafts 68, 69 are longer than the length in the running direction (length in the width direction) of the first carriage 25 as an exposure unit including the carriage base 61, the reflector 62, the exposure lamp 42 and the like. Has full length. Both ends of the support shafts 68 and 69 are first
It is located at a position largely protruding from the end of the carriage 25 in the width direction, and the central portion is fixed to the carriage base 61 by fixing tools 68a and 69a.

Contact members 70 and 71 made of synthetic resin as fulcrums are detachably attached to both ends of the support shafts 68 and 69 protruding from the first carriage 25. The contact members 70 and 71 have a hemispherical bottom surface and are in point contact with flat surface portions 72a and 73a of guide rails 72 and 73, which will be described later. The support shafts 68, 69 support the first carriage 25 by bringing their contact members 70, 71 into contact with a pair of guide rails 72, 73 as guide means provided in the apparatus main body 11. The pair of guide rails 72,
Flat portions 72a and 73a are formed on the upper surface of 73, and the support shafts 68 and 6 are formed on the flat portions 72a and 73a.
The contact members 70 and 71 of 9 are adapted to come into point contact and slide. Here, the flat surface portions 72a and 73a of the guide rails 72 and 73 are smoothed in order to reduce friction generated between the support shafts 68 and 69 and the contact members 70 and 71.

Further, as shown in FIG. 5, drive belts 76 and 77 are fixed to both ends of the carriage base 61 through fixing members 74 and 75. The drive belt 7
6, 77 are respectively hung on the pulleys 78, 79, and the pulleys 78, 79 are connected via the shaft 80. The shaft 80 includes a pulley 81 and a gear belt 8
2, the shaft 85 of the drive motor 84 via the pulley 83
Are linked to.

When forming an image, the document G is set on the document table glass 13 and the copy button 17 of the operation unit 14 is turned on. As a result, the exposure lamp 42 is turned on, and the first and second carriages 25 and 26 travel along the platen glass 13. At this time, the first carriage 25 is moved by the traveling of the drive belts 76 and 77. The driving force of the driving motor 84 is transmitted to the shaft 80 by the gear belt 82, and the pulleys 78 and 79 rotate. The drive belts 76 and 77 are rotated by the rotation of the pulleys 78 and 79, and the first carriage 25 is run along with this rotation. At this time, the support shafts 68 and 69 of the first carriage 25 have their contact members 70 and 71 connected to the flat portions 72 of the guide rails 72 and 73.
It is slid on a and 73a and runs. here,
In this embodiment, the first carriage 25 is accelerated by the acceleration curve as shown in FIG.
It is scanned at the speed of. As shown in FIG. 5, the first carriage 25 is fixed to the drive belts 76 and 77 by the fixtures 74 and 75.
The first carriage 25 is caused by the rotation of 6, 77.
Is to be moved. Here, in FIG. 7, the center of gravity G of the first carriage 25, the fixing point a to the drive belt 76 (77), the contact members 70 and 71, and the guide rails 72 and 7 are shown.
3 shows the relationship between the contact points q and r. In FIG. 7,
For convenience, the shape of the first carriage 25 is shown as a rectangle.
Here, the center of gravity G and the fixed point P are located at the center in the width direction of the first carriage 25.
The length of the shafts 68 and 69 of 5 is 2L. In addition, the distance between the center of gravity G and the fixed point P is 1, and the first carriage 2
The weight of 5 is m.

Further, the acceleration when moving the first carriage 25 is a, and the gravitational acceleration is g. In this definition, the contact points q and r of the first carriage 25 with the guide rails 72 and 73 are applied with a force of F ′ = mg / 2 in the gravity direction. Drive belt 76
(77) is rotated and the first carriage 25 is accelerated a
When accelerated by, a force F = ma is applied to the fixed point O between the first carriage 25 and the drive belt 76 (77) in the moving direction of the first carriage 25. At this time, the first carriage 25 is centered on the center of gravity G and M =
A moment of l · ma occurs. At this time, the following force F ″ acts on point q shown in FIG.

F ″ = F′−M / L (1) Here, when the force in the (−) direction shown in FIG. 7 occurs at point q, the first carriage 25 jumps up.

As described above, when the force F ″ acting on the first carriage 25 is negative, jumping occurs. That is, when F ″ = F′−M / L <0 (2), the first carriage 25 jumps up.

Therefore, in order to prevent the first carriage 25 from jumping up at point q during acceleration, it is sufficient that F ″ = F′−M / L> 0 (3).

That is, mg / 2−M / L ≧ 0 (4) M / L ≦ mg / 2 (5) l · ma ≦ mgL / 2 (6), and the shafts 68, 69 of the first carriage 25 are If the length satisfies S = 2L ≧ 4al / g (7), the first carriage 2 at the time of acceleration
It is possible to prevent the jumping up of 1.

As the first carriage 25 travels, the original G on the original table glass 13 is scanned with light, and the original G
The reflected light reflected from the first to third reflection mirrors-4.
It is sent to the lens 46 through 3, 44 and 45, and after passing through this lens 46, the fourth to sixth mirrors 47 to 49.
An image is formed on the photosensitive drum 20 via the. The surface of the photoconductor drum 20 is charged by the charging charger 21, and an electrostatic latent image of the document G is formed by the image formation. This electrostatic latent image is developed by the rotation of the photosensitive drum 20 to the developing device 23.
The toner as a developer is supplied from the developing device 23 and is developed.

On the other hand, at this time, the paper feed cassettes 35 to 35
38, or a large-capacity paper feed cassette 3
The paper is sent out from 9. This sheet is sent to the registration roller 32, where it is aligned and then the photosensitive drum 20.
The image is transferred to the image transfer section between the transfer charger 24 and the transfer charger 24. The sheet on which the image is transferred is peeled from the photoconductor drum 20 by the action of the peeling charger 27. Then, the peeled sheet is conveyed by the conveyor belt 33.
Is conveyed to the fixing device 34. The sheet conveyed to the fixing device 34 is pressurized here to fix the image. After that, the paper is discharged onto the paper discharge tray 16 via the discharge roller 38 and the discharge roller 40 at the time of normal copying, and at the conveying path via the gate 51 at the time of overlapping copying. Sent to 52.

As mentioned above, the support shafts 68, 69
Since the contact members 70 and 71 as support members at both ends of the first carriage 25 as the exposure unit including the carriage base 61, the reflector 62, and the exposure lamp 42 are projected from the end portions in the width direction of the reflector 62, Center of gravity, the center of gravity of the mirror 43, and the center of gravity of the carriage base 61 are all located inside the contact members 70 and 71 and do not shift outward, and the stability of the carriage 25 in the traveling direction is significantly improved. . As a result, the first carriage 25 does not shake during the exposure scanning, and the image formation is not adversely affected.

The length 2L of the support shafts 68 and 69 varies depending on the size of the reflector 62 and the size of the cover 66, and in any case, it is set so as to satisfy the above expression (1). And various components (components attached to the carriage 25) within the traveling width of 2 L.
If all the center of gravity of the carriage 25 can be accommodated, the carriage 25 does not shake during traveling and the stability in the traveling direction can be improved. In addition, the guide rails 72, 73
Is formed by bending the upper end portions of the side frames 86, 86, and the upper surface portion thereof is made of a super-high molecular weight polyethylene sheet having a thickness of 0.65 mm and having high wear resistance which constitutes the flat portions 72a, 73a. Is attached. Thereby, the friction between the contact members 70 and 71 of the first carriage 25 is reduced, and the friction between the contact members 70 and 71 can be prevented.

The contact members 70 and 71 may be fixed to the shafts 68 and 69 by an adhesive or welding, or may be detachably press-fitted or hooked to be attached.

Although the support shafts 68 and 69 are used as the support means in the above-described embodiment, the support means is not limited to this, and the support shafts shown in FIGS. 8 and 9 may be used.

That is, both ends of the carriage base 61 in the direction orthogonal to the traveling direction are integrally extended along the traveling direction, and the extending portions 81 and 82 serve as supporting means. Contact members 83 and 84 as fulcrums are detachably attached to both ends of the extending portions 81 and 82 of the carriage base 61, and these contact members 83 and 84 are attached to the guide rail 7.
The flat surface portions 72a and 73a of the reference numerals 3 and 73 are point-contacted and supported. The exposure lamp 42 and the first reflection mirror-4 are provided between the contact members 83 and 84 provided at both ends of the extending portions 81 and 82 with respect to the carriage base 61.
The first carriage 21 having the number 3 is mounted.

Further, the contact members 83 and 84 are detachable from the carriage base 61 and can be easily replaced when worn.

[0047]

As described above, according to the present invention,
The center of gravity of the exposure scanning unit can be located between the contact members without increasing the weight, and the stability of the exposure scanning unit during traveling is good. Therefore, the exposure scanning unit does not jump at the time of acceleration and deceleration, an image can be formed well, and noise is not generated.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an electronic copying machine that is an embodiment of the present invention.

FIG. 2 is an internal configuration diagram showing the electronic copying machine of FIG.

3 is a perspective view showing an optical device provided in the electronic copying machine of FIG.

FIG. 4 is a side sectional view showing the optical device of FIG.

5 is a perspective view showing a drive system of the optical device shown in FIG. 3;

6 is a diagram showing an acceleration curve in which the optical device of FIG. 3 travels stably.

7 is a diagram showing a relationship of forces applied to the optical device of FIG.

FIG. 8 is a plan view showing a carriage base of an optical device according to another embodiment of the present invention.

9 is a side view showing the carriage base of FIG.

[Description of Reference Signs] 13 ... Original platen glass (original platen), 25 ... First carriage (exposure scanning means), 72, 73 ... Guide rail (guide means), 68, 69 ... Support shaft (supporting means), 7
0, 71 ... Contact member (contact means), 76, 77 ... Drive belt, 90 ... Drive motor (drive means), 81, 82 ... Extension part (support means), 83, 84 ... Contact member (contact means) ).

Claims (6)

[Claims] 1. An exposure scanning means for scanning a document placed on a document table in a predetermined direction while exposing it, and a guide means for mounting the exposure scanning means and slidably guiding the exposure scanning means. And has a length longer than the width of the exposure scanning means in the scanning direction, and is provided on both ends of the exposure scanning means in a direction orthogonal to the scanning direction, and supports the exposure scanning means on the guide means. Supporting means, contact means provided at both ends of the supporting means in a direction parallel to the scanning direction and contacting the guide means, and a drive belt fixed to a part of the exposure scanning means, Driving means for sliding the exposure scanning means in a state where the contact means of the supporting means is in contact with the guide means by driving the belt. Optical device. 2. The exposure means is arranged so that both ends of the support means in a direction parallel to the scanning direction project from both ends of the exposure means in a direction parallel to the scanning direction. The optical device according to claim 1, wherein the optical device is attached. 3. The guide means has a flat surface portion subjected to a smooth surface treatment, the contact means has a hemispherical projection portion, and the guide means are in point contact with each other. The optical device according to claim 1. 4. A movable exposure scanning means for scanning a document placed on a document table while exposing it, a guide means for guiding the movement of the exposure scanning means, and a direction orthogonal to the scanning direction of the exposure scanning means. A rod-shaped member provided at both end portions on the side and having a length longer than the width of the exposure scanning unit in the scanning direction, and both end portions of the rod-shaped member on the side parallel to the scanning direction of the exposure scanning unit. An optical device, comprising: a support member that is provided to support the rod-shaped member on the guide means. 5. The exposure means is arranged such that both ends of the support means in a direction parallel to the scanning direction project from both ends of the exposure means in a direction parallel to the scanning direction. The optical device according to claim 4, wherein the optical device is attached. 6. The guide means has a flat surface portion subjected to a smooth surface treatment, the support member has a hemispherical projection portion, and the guide means are in point contact with each other. The optical device according to claim 4.