JP3292501B2 - Document scanning optical device of image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original scanning optical device for an image forming apparatus.

[0002]

2. Description of the Related Art In an original scanning method for exposing or reading an original in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, a scanner, etc., an original placed at a predetermined position on a contact glass is scanned by an optical system. Is moved and scanned to form an image on a photoreceptor or image sensor such as a CCD to perform exposure or reading, and an optical system fixed at a predetermined position while moving an original at a constant speed. There is a document moving optical system fixing system for forming an image on a body or an image sensor, and both are widely adopted.

A typical example of an original scanning optical apparatus using an optical system moving system will be described with reference to FIG. This figure shows a schematic configuration of a document reading section of an image scanner or a digital copying machine.
An image is formed on the upper side, the main scanning is performed by the self-scanning of the CCD, and the sub-scanning is performed by moving the optical system. In an exposure optical device of an analog copying machine, an original image is formed on a rotating photoconductor by an optical system, and exposure scanning is performed by moving the optical system and rotating the photoconductor. In this specification, the moving direction of the optical system is referred to as a scanning direction, and a direction parallel to the document surface and perpendicular thereto is referred to as a scanning width direction.

In FIG. 6, a light source lamp 3 for illuminating the original 1 in a slit shape directly below a contact glass 2 on which the original 1 is placed, and the reflected light from the illuminated original is reflected parallel to the original surface. A first mirror 4 is provided, and the traveling direction of the original light reflected by the first mirror is reversed by a second mirror 5 and a third mirror 6 which are orthogonal to each other, and formed on a CCD 8 by an imaging lens 7. The document image is read.

[0005] The light source lamp 3 and the first mirror 4 are integrally mounted on a first carriage 9, and second and third mirrors 5, 6 are provided.
Are integrally mounted on the second carriage 10.

In the original reading scanning, the first carriage 9 is moved at a constant speed V in a scanning direction parallel to the original surface,
By moving the carriage 10 in the same direction in synchronization with the movement of the first carriage at a speed of V / 2, the optical path length from the document surface to the imaging lens is always kept constant, and the image light is transferred onto the CCD 8. An image is formed.

As means for synchronously moving the first carriage 9 and the second carriage 10 at a speed ratio of 1: 1/2, one of the wire ropes 17 moved by one motor as shown in FIG. The point is fixed to a member 15 fixed on the first carriage 9 by a clamp 15a, and the same wire rope 17 is wound around a pulley 16 supported on a shaft fixed to the second carriage 10, and the wire rope 17 is fixed. Is moved at the speed V, so that the moving speed of the pulley 16 becomes V /
The one utilizing the principle of the so-called moving pulley which is 2 is widely adopted.

First carriage 9 and second carriage 10
As shown in FIG. 7, stay members 11 and 12 for holding optical components such as a light source lamp and a mirror, and a slide portion 1 provided at both ends in the scanning direction and sliding along a slide rail.
3 In order to improve the stability of the stay member, the slide portion 13 is provided on the lower surface of the end of the protrusion protruding forward and backward in the scanning direction at both ends of the stay portion.

The apparatus main body is provided with a pair of common slide rails 14 for guiding the slide portions 13 on both sides of the first and second carriages.

Conventionally, the slide shoe has a pipe shape on one side and a roller type rolling on a flat rail on the other side, and accordingly, one slide rail has a round bar shape.
Although the other side is often used as a horizontal plane, recently, in order to reduce the height of the optical device, as shown in this figure, both sides are formed as horizontal plane rails, and the rail is slid thereon. A type provided with a moving slide shoe 13 is used. In this case, the width of the stay members 11 and 12 in the scanning direction is reduced to reduce the size of the apparatus in the scanning direction. The width of the stay member in the scanning direction can be determined by the portion provided with the guide shoes at both ends, but if the distance between the slide shoes before and after the scanning direction of the carriage is small, it is possible to obtain stable driving during startup, deceleration, and rapid acceleration of scanning. Can not.

In FIG. 6, since the distance between the first and second carriages becomes narrower as they move to the left, the first and second carriages are sufficiently separated from each other at the scanning start position to increase the scanning advance distance. If there is no starting position, the first and second
The carriages will interfere with each other.

Therefore, it is conceivable to provide two stages of slide rails separately for the first carriage and the second carriage so as to increase the interval between slide shoes of the same carriage and to avoid interference during running. In this case, the control of the parallelism and the mounting direction of the slide rails provided in two stages becomes extremely strict, resulting in high costs, a complicated configuration, and an increase in the external dimensions of the apparatus.

Also, due to undulations and scratches on the slide rail,
When the slide shoe of the carriage passes through the place, vibration occurs in the carriage, and as a result, an image may be deteriorated.

[0014]

SUMMARY OF THE INVENTION The present invention relates to a document scanning optical system having the above-mentioned configuration, in which a pair of horizontal flat slide rails are provided on the left and right as guide rails of a carriage. In view of the drawback, there is provided an original scanning optical device which can increase the distance between the slide shoes of the first and second carriages in the scanning direction and increase the stability of the carriage and the approach distance without increasing the size of the device. It is a second object of the present invention to provide a document scanning optical device which does not vibrate the carriage even if the slide rail has undulations or scratches, thereby preventing image deterioration. Subject.

[0015]

According to a first aspect of the present invention, there is provided an original scanning optical apparatus having the above-described configuration.
The slide shoes on both sides of one of the first and second carriages are provided outside the scan width of the slide shoes on both sides of the other carriage in a range where they do not interfere with each other.

Further, if the height of the outer slide shoe in the scanning width direction is made higher than the height of the inner slide shoe so that the stay members of both carriages do not interfere with each other, the effect is further enhanced. The second problem is solved by mounting the elastic member between the slide shoe and the stay member in the original scanning optical device having the above-described configuration.

[0017]

According to the former structure for solving the first problem, the slide shoes on the same side of the first carriage and the second carriage are provided in a range that does not interfere with each other in the scanning width direction. The projections for providing the slide shoes of both carriages can be overlapped by being arranged in the scanning width direction in the same plane. Therefore, it is possible to increase the interval between the slide shoes by an amount corresponding to the overlap, or to avoid interference between the first carriage and the second carriage at the time of starting the approach.

Further, by changing the height of the slide shoes of the two carriages as described above, the stay portion of one carriage can be inserted under the stay portion of the other carriage to some extent. The effect is further improved.

Further, in order to solve the second problem, an elastic member is interposed between the slide shoe and the stay member, so that the vibration of the slide shoe caused by the undulations and scratches of the slide rail is absorbed by the elastic member. Thus, vibration of the stay member, and furthermore, the optical member such as a mirror carried on the stay member is eliminated or reduced, and deterioration of the image due to the vibration can be prevented.

Other problems and means for solving the problems of the present invention will be apparent from the description of the embodiments which will be described in detail below with reference to the drawings.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a view showing the first and second carriages 9 and 10 and a slide rail 14 according to the first embodiment of the present invention.

In this embodiment, the distance c between the slide shoes 13b on both sides of the second carriage 10 is at least smaller than the distance d between the slide shoes 13a on both sides of the first carriage 9 in the slide shoes 13a, 13b. Is set to be larger than the width of the protrusion protruding forward and backward from the stay in the scanning direction.

Therefore, the first and second carriages 9, 1
The sliding areas of the 0 slide shoes 13a and 13b on the slide rail 14 in the scanning width direction do not interfere with each other.

Therefore, at the start of the scanning run, FIG.
As shown in FIG. 5, the projection for attaching the slide shoe 13a projecting from the stay 11 of the first carriage 9 enters the inside of the projection for attaching the slide shoe 13b projecting from the stay 12 of the second carriage 10, and surprisingly, The slide shoe 13a of one carriage 9 is
Of the slide shoe 13b of FIG. As a result, the approach distance can be extended by an amount a in which one protrusion enters from the tip of the other protrusion. Further, the distance between the slide shoes in the scanning direction of each carriage can be increased without interfering with each other, so that the stability can be improved and the width of the apparatus body in the scanning direction can be reduced.

As described above, when the slide shoes on both sides of the first and second carriages are provided so as to be shifted inward and outward, respectively, as shown in FIG. A flange is provided, the outer peripheral surface of the inner slide shoe is engaged with the inner flange inner surface of both slide rails, and the outer peripheral surface of the outer slide shoe is engaged with the outer flange inner surface of both slide rails. Accordingly, meandering of the first and second carriages can be prevented.

FIG. 3 shows the first and second embodiments of the second embodiment of the present invention.
It is a figure which shows the engagement part with a carriage, a slide rail, and a drive wire rope. In this embodiment, not only the sliding areas of the slide shoes 13a and 13b of the first and second carriages 9 and 10 in the scanning width direction do not interfere with each other, but also the heights of the slide shoes 13a and 13b are different. The lower slide shoe (13b in the figure) can be lowered to some extent without lowering the stay without interfering with the other stay. The amount of depression depends on the point at which the bracket holding the mirror hits the other stay, or the point at which the arm holding the engaging portion with the drive wire hits the other slide shoe.

As a result, the amount by which the tip of the protrusion of one carriage can penetrate the tip of the protrusion of the other carriage becomes b larger than a in the first embodiment, and further increases the approach distance, or The width of the apparatus in the scanning direction can be increased.

As shown in FIG. 4, if the slide shoe 13 is attached to the stays 11 and 12 via the vibration isolating rubber 18, even if the slide rail 14 has undulations and scratches, the slide shoe 13 will vibrate. , Vibration is anti-vibration rubber 1
8, the stay and the mirror and the like carried on the stay do not vibrate, so that deterioration of the image due to the vibration can be prevented.

In changing the height of the slide shoes 13a, 13b of the first and second carriages 9, 10, the shape of the slide shoe body 13c is made the same as shown in FIG. By changing the total height, a cost reduction effect can be obtained by mass-producing the slide shoe body.

When the first and second carriages have a flat plate shape and the slide rails have a flat plate shape, a member for locking a wire rope for driving each carriage, or an arm having a pulley for winding the wire rope at a tip thereof. One may intersect the wire rope approximately coplanar. In this case, as shown in FIG. 3, if the arm crossing the wire rope 17 is bent so as not to contact the wire rope 17 and straddles the wire rope, the carriage can be smoothly scanned and driven.

[0032]

As described above, according to the present invention, the approach distance at the time of scanning can be increased without increasing the width of the apparatus in the scanning direction, and the posture of the carriage can be stabilized. This is effective in improving the quality of the product. Also, by attaching the slide shoe to the stay of the carriage via the elastic member, even when the slide shoe vibrates due to the undulation or damage of the slide rail, the carriage and the optical members such as mirrors carried on the carriage do not vibrate. This is effective in improving image quality. Further, by changing the height of the slide shoe by the size and shape of the elastic member interposed between the stay and the stay, mass production of the slide shoe body can be achieved, and the effect of cost reduction can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a carriage and a slide rail according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation.

FIG. 3 is a perspective view showing a main part of a second embodiment of the present invention.

FIG. 4A is a cross-sectional view showing a state in which a slide shoe is attached to a stay of a carriage via an anti-vibration rubber;
(B) is sectional drawing of a vibration-proof rubber.

FIG. 5 is a cross-sectional view showing a state in which the height of the slide shoe is changed according to the height of a vibration-proof rubber.

FIG. 6 is a cross-sectional view illustrating an overall configuration of an example of a document scanning optical device of a conventional image forming apparatus.

FIG. 7 is a perspective view showing the carriage and an engagement portion of the drive wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original 3 Light source lamp 4 1st mirror 5 2nd mirror 6 3rd mirror 7 Imaging lens 8 CCD 9 1st carriage 10 2nd carriage 11,12 Stay member 13,13a, 13b Slide shoe 14 Slide rail 15 Locking part 16 Pulley 17 Wire rope 18 Anti-vibration rubber

Claims (5)

(57) [Claims] 1. A light source for illuminating a document placed on a document placing glass in a slit shape, and a first mirror for reflecting reflected light from the document illuminated by the light source in parallel to the document surface. A first carriage that moves at a predetermined speed in the scanning direction; and a second mirror and a third mirror that invert the reflected light from the first mirror and that are orthogonal to each other. A second carriage that moves in the same direction in synchronization with the first carriage at a speed of 2. The first and second carriages each include a stay member that supports an optical element and a scan of the stay member. A pair of slide shoes provided on the lower surface of the end portion of the protrusion projecting back and forth in the scanning direction at both ends in the width direction, wherein the slide shoes of the first and second carriages slide in common on the upper surface and extend in the scanning direction. The horizontal plane In a document scanning optical device of an image forming apparatus having a ride rail, a range in which the slide shoes on both sides of one of the first and second carriages do not interfere with each other outside of the slide shoes on both sides of the other carriage in the scanning width direction. An optical device, comprising: Further, the height of the slide shoe on the outer side in the scanning width direction is higher than the height of the inner slide shoe so that the stay members of both carriages do not interfere with each other. The optical device according to claim 1. 3. The optical device according to claim 1, wherein an elastic member is interposed between the stay member and the slide shoe of each of the carriages. 4. An apparatus according to claim 1, wherein an elastic member is interposed between the stay member and the slide shoe of each carriage, and the height of the slide shoe including the elastic member is changed by changing the height of the elastic member. The optical device according to claim 2, wherein: 5. The first and second carriages are locked to arm ends extending outward from ends in the scanning direction of the respective carriages, or wound around pulleys pivotally supported by the arm ends. Driven via the turned wire rope, at a position where one of the arms intersects with the wire rope, the arm is bent so as to straddle the wire rope so that the wire rope and the arm do not contact each other. The optical device according to claim 1, wherein: