JP2000216955A - Image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of parallelism between a second traveling body and a first traveling body at driving by a wire (belt), due to the adhesion and accumulation of dusts or the like in the outer peripheral grooves of a pulley provided at the second traveling body, and to prevent the deterioration of reading image quality, as a result in a differential drive mechanism using a wire (belt) and a pulley for moving the second traveling body, at a speed which is 1/2 that of the first traveling body. SOLUTION: This image reading device is provided with a first traveling body moving, while supporting a light source for irradiating an original face with lights and an optical part for introducing original reflected lights to a prescribed direction, a second traveling body 7 moving at a prescribed speed while supporting the optical parts, and a drive mechanism constituted of a traveling body pulley 15 supported by the second traveling body so as to be freely rotatable and a wire 22 to be wound around the traveling pulley for driving the both traveling bodies at a prescribed speed difference. A cleaning member 40 is arranged at the second traveling body, so as to be brought into contact with an area in which a wire is not wound in grooves from among those formed on the outer peripheral face of the pulley.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an image reading apparatus used for an image forming apparatus such as a copying machine, a scanner, and the like, and more particularly, to a first traveling body which moves while supporting a light source and a mirror, and an optical component. And a second traveling body that supports the second traveling body and moves in the same direction at half the speed of the second traveling body. The present invention relates to an image reading apparatus capable of effectively preventing a deviation in parallelism between both traveling bodies caused by the attachment of dirt and the like.

[0002]

2. Description of the Related Art An arrangement for guiding reflected light of a document obtained by irradiating light from a light source onto an image surface of a document set on a document table such as a contact glass in a predetermined direction by using an optical component such as a mirror. Is used in image forming apparatuses such as copiers and scanners. For example, an image reading device used in a copying machine includes a first traveling body that includes a light source and a mirror and travels in a predetermined direction.
A second traveling body or the like that has a mirror and travels at a required speed in the same direction as the first traveling body is provided, and each traveling body (scanning unit) is provided with a guide member (scanning unit) provided on a housing of the image reading apparatus. And a reciprocating operation by a driving force transmitted from a driving force transmitting means such as a pulley or a belt driven by a driving source from a motor. Since it is absolutely necessary for the first and second traveling bodies to stably travel at a required speed while maintaining accurate parallelism, it is an absolutely necessary requirement to maintain image reading accuracy. Consideration must be given to the precision of the wire, the precision of the pulley around which the wire is wound, and the like. Also,
A differential drive mechanism for moving the second traveling body at half the speed of the first traveling body is provided on the device housing side, and the accuracy of each component constituting the differential drive mechanism is also high. This is an important factor in ensuring image reading accuracy. by the way,
As a method for driving the traveling body of the image reading apparatus, there are a one-side drive system and a two-side drive system. The one-side drive system is a system in which a guide rod is provided on the housing (frame) side, a slider member that slides along the guide rod is mounted on the traveling body side, and the vicinity of the slider member is driven by a single wire. In this method, the behavior of the traveling body on the drive side and the driven side is different due to imbalance in how the driving force is applied from the wire, backlash between the guide rod and the slider member, deflection of the rod, and the like. As a result, there is a problem that the image quality degradation on the driven side increases. Also,
In the double-side drive system, guide rails are provided along both side walls of the housing, sliders guided by the guide rails are mounted on the running body side, and one wire is arranged on both sides of the running body, and total This is a method of driving with two wires. According to this method, the disadvantage of the one-sided driving method is eliminated, and most image reading apparatuses currently employ this two-sided driving method.

However, in recent image reading apparatuses and image forming apparatuses using the same, the requirements for the image quality of the obtained read image have become more severe. One of such requirements is a vertical line (scanning). (Straight line parallel to the direction). Due to this vertical line, the relative positional relationship between the first traveling body and the second traveling body during the scanning of the traveling body is shifted between the front and rear of the machine, that is, both ends of the traveling body where the wire is hung, that is, the first traveling body
It has been known that this occurs due to a deviation in the parallelism between the traveling body and the second traveling body. One of the factors that cause the parallelism between the first traveling body and the second traveling body to shift is the accuracy of the pulley provided on the second traveling body. That is, the second
A rotatable pulley is supported at both ends in the longitudinal direction of the traveling body, and a driving force from the wire is transmitted to the second traveling body by winding the wire around a groove on the outer periphery of the pulley. Among the required precisions required for pulleys are the eccentricity of the outer circumferential groove around which the wire is wound and the roundness of the outer circumferential groove, and very tight tolerances (0.05 mm or less) are applied as these tolerances. The required image quality is satisfied by tightening the tolerance. However, dust and dirt usually adhere to the groove on the outer periphery of the pulley with time, and if dust and the like adhere to the groove, the dimensional tolerance, which should be strictly suppressed, increases, and the image quality deteriorates. The problem described above occurs. That is, first engagement of the wire into the outer peripheral groove of the pulley to which no dirt or the like is adhered causes the first
Despite the fact that the parallelism of the second traveling body with respect to the traveling body can be properly maintained, dust and the like adhere to and accumulate in the groove, thereby reducing the substantial dimensional tolerance of the groove, causing eccentricity, and As a result, the degree of circularity is deteriorated, and the parallelism between the two traveling bodies is shifted, which causes a problem that a read image with a vertical line is obtained.

[0004]

An object of the present invention is to use a wire (belt) and a pulley to move the second traveling body at half the speed of the first traveling body. In the differential drive mechanism, the degree of parallelism between the second traveling body and the first traveling body when driven by a wire due to dust and the like being deposited in the outer peripheral groove of the pulley provided on the second traveling body is reduced. It is an object of the present invention to provide an image reading apparatus capable of solving the problem that the reading quality is lowered and the reading image quality is lowered.

[0005]

In order to achieve the above object, the present invention is directed to a light source for irradiating light to a document surface and an optical component for guiding reflected light of the document in a predetermined direction. A first traveling body, a second traveling body that supports an optical component and moves at a predetermined speed, a traveling body pulley rotatably supported by the second traveling body, and a winding around the traveling body pulley. And a driving mechanism for driving both traveling bodies at a predetermined speed difference, wherein the driving mechanism comprises: The cleaning member is arranged on the second traveling body so as to be in contact with the second traveling body. Claim 2
The cleaning member according to claim 1, wherein the cleaning member is a roller-like member rotatably supported by a second traveling body around a center portion as a rotation center, and the cleaning member is driven to rotate with rotation of the traveling body pulley. Features. According to a third aspect of the present invention, in the second aspect, a one-way clutch is provided at a central portion of the roller-shaped cleaning member so that the cleaning member rotates only following rotation of the traveling body pulley in one direction. It is characterized by having comprised in.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 is an internal configuration diagram of an image reading apparatus as one embodiment of the present invention, and FIG. 2 is a perspective view of a main part thereof (schematic diagram of a traveling body drive system). The image reading apparatus has a configuration in which the opening of the housing 1 having an open upper surface is closed by a contact glass 30, and optical components and components constituting a driving mechanism are stored and supported inside the housing 1. . That is, reference numeral 1 denotes a box-shaped housing having an open upper surface, and guide members (not shown) are arranged on inner surfaces of two opposing side walls 2 and 3 of the side walls 2 to 5 of the housing 1. Both ends of the first traveling body 6 and the second traveling body 7 are supported by the two guide members so as to be able to advance and retreat in the scanning direction indicated by arrows. Reference numeral 8 denotes an imaging lens 8
a, an image reading unit including a CCD 8b. The first traveling body 6 moves forward and backward with the light source 10, the mirror 11, and optical components such as a reflection plate mounted on the carriage 12.
The second traveling body 7 advances and retreats separately from the first traveling body with the optical components such as the mirrors 13a and 13b mounted on the carriage 14.

A drive mechanism for each traveling body in the image reading apparatus is constituted by a traveling body pulley (idler pulley) 15 rotatably supported at both longitudinal ends of the carriage 14 of the second traveling body 7 and a drive motor 19. A drive pulley 17 having a shaft center fixed to both ends of a drive shaft 16 that is driven to rotate.
And housing-side turn pulleys 20 and 21 arranged at appropriate places on the side walls 2 and 3 of the housing 1, and a wire 22 wound around these pulleys. The two wires 22 have one ends 22a fixed to the housing 1, and the wire portions extending in the forward direction from the one end 22a are wound around the circumference of the traveling body pulley 15 at both ends of the carriage 14 of the second traveling body 7 by a half turn. After being attached, it is reversed in the return direction, and is reversed in the forward direction around the outer periphery of the first turn pulley 20 supported by the device housing.
7 is wound around the outer circumference by one turn, and then extends in the forward direction. The wire 22 extending in the forward direction from the driving pulley 17 is wound around the outer circumference of the second turn pulley 21 by a half turn and then reversed in the return direction, and a part of the wire 22 is clamped and fixed to both ends of the carriage 12 of the first traveling body. I do. A wire 22 extending further in the return direction from both ends (clamps) of the carriage 12 of the first traveling body is
Traveling body pulley 15 supported at both ends of the carriage 14
Is wound around the outer circumference for half a turn, and then reverses in the forward direction. The other end 22b of the wire 22 extending in the forward direction is supported by the housing via a spring (not shown).

Next, when reading the original set on the contact glass 30, the original is exposed by the light source 10 mounted on the first traveling body 6. The reflected light from the original is transmitted to the first mirror 11 and the second traveling body 7 mounted on the first traveling body 6.
The light is reflected by the second mirror 13a and the third mirror 13b mounted on the CCD and is incident on the CCD 8b through the lens 8a. The first traveling body 6 and the second traveling body 7 perform reading by scanning from left to right in the drawing (forward direction). The second traveling body 7 moves at half the speed of the first traveling body 6 to keep the distance from the document to the lens constant. FIGS. 3 and 4 are exploded views showing a configuration example of the traveling body pulley supported by the carriage of the second traveling body. In the example of FIG. 3, two pulley members are attached to a shaft 14 a protruding from both side end surfaces of the carriage 14. The pulley member 15a is rotatably supported by fitting each shaft hole of 15a. The pulley member 15a is non-detachably and rotatably supported by press-fitting or using a retaining ring. In the example of FIG. 4, the pulley members 15a are rotatably supported by fitting the respective shaft holes of the respective pulley members 15b with the two shafts 14b provided on both side end surfaces of the carriage 14, respectively. The pulley member 15a is non-detachably and rotatably supported by press-fitting or using a retaining ring. Each pulley member 15a is mainly made of a highly lubricating resin, and a ball bearing is inserted into the center of the pulley member 15a, so that the pulley rotates smoothly and the driving load is stabilized. The difference between the pulley support structures shown in FIGS. 3 and 4 is the degree of selection depending on the space of the reader, the manner of turning the wires, the method of attaching the pulleys, and the like, and there is no substantial difference. In the present invention, description will be made using the pulley of FIG. 4 for convenience of explanation.

FIGS. 5 (a) and 5 (b) are a front view of a main part showing a configuration of an embodiment of the present invention and a perspective view of a cleaning member supporting plate. This embodiment is characterized in that a cleaning member 40 that fits into the outer peripheral groove 15A of the traveling body pulley 15 supported by the carriage 14 and constantly cleans the outer peripheral groove when the pulley rotates is fixed in place on the carriage. It is a target. That is,
Cleaning member 40 made of felt, sponge, etc.
Is fixed to an end of the support plate 41 with an adhesive or a double-sided tape, and the support plate 41 is fixed to an end surface of the carriage 14 by fixing means such as a screw. Therefore, the cleaning member 40 is positioned so as to contact the outer peripheral groove (wire groove) of the second traveling body pulley 15. The cleaning member 40 is arranged along a region of the pulley outer peripheral groove where the wire 22 is not wound. When the traveling body moves, the cleaning member 4
Since the dust and dirt accumulated in the wire groove of the second traveling body pulley 15 can be removed by 0, the dimension in the groove of the second traveling body pulley 15 does not change apparently,
It is possible to maintain stable image quality over time. That is, when the diameter inside the outer peripheral groove 15A is eccentric or increases, the second traveling body 7 is slightly tilted when the wire is wound, and as a result, the parallelism between the second traveling body 7 and the first traveling body 6 deteriorates. However, in the present embodiment, it is possible to reliably prevent a change in the dimension in the groove of the second traveling body pulley 15 due to the attachment and accumulation of dust and the like in the outer peripheral groove.
In this embodiment, since the cleaning member 40 cleans the inside of the outer circumferential groove by rotating the second traveling body pulley 15,
Cleaning is performed when the second traveling body 7 moves in both the forward direction and the return direction. Further, a cleaning member having the same configuration may be disposed so as to be in sliding contact with the outer peripheral groove of another adjacently disposed second traveling body pulley 15 to clean the other pulley. Alternatively, a cleaning member that slides on the wire 22 to remove the stain on the wire may be provided on the support plate 41.

FIGS. 6 (a) and 6 (b) are a front view and an exploded perspective view showing a configuration example of a means for cleaning a second traveling body pulley according to another embodiment of the present invention. The cleaning member 45 of this embodiment is a donut-shaped member whose center hole is rotatably supported by a shaft 46 protruding from the end surface of the carriage 14, and the outer peripheral surface of the cleaning member 45 is formed of the second traveling body pulley 15. The outer peripheral groove 15A is configured to come into contact with and be cleaned. This cleaning member 45 rotates (slids and rotates) with the second traveling body pulley when the traveling body moves.
Then, dust accumulated in the outer peripheral groove of the second traveling body pulley is removed. The cleaning member 45 is made of felt, sponge, or the like. In the cleaning method of this embodiment, the cleaning member 4
5 rotates together with the second traveling body pulley 15, so that the second traveling body pulley can rotate more smoothly than in the case of the first embodiment, and the adverse effect on the image quality can be prevented. Next, FIGS. 7A and 7B are a front view and an exploded perspective view of a main part showing a configuration example of a means for cleaning a second traveling body pulley according to another embodiment of the present invention. This cleaning member 50 has the same donut shape as the cleaning member of FIG. 6, and further has a one-way clutch 51 inserted into the center hole thereof. The one-way clutch 51 is attached to the traveling body base such that the second traveling body pulley 15 rotates only in the direction of rotation shown by the arrow C. That is, when scanning the traveling body in the forward direction (when reading an image), the traveling body 14
Moves in the direction of arrow A, and at this time, the second traveling body pulley 15 rotates in the direction of arrow B. Therefore, the cleaning member cleans the inside of the outer peripheral groove 15A of the pulley while rotating in the same manner as in the case of FIG. Conversely, at the time of the return operation in which the traveling body 14 returns to the image reading start position, the rotation of the cleaning member 50 is stopped and comes into contact with the outer peripheral groove of the pulley. In the method of this embodiment, the cleaning member 50 can be caused to rotate only during the scanning of the traveling body where smooth rotation of the second traveling body pulley is required, which may involve an increase in driving load and a lack of stability. Therefore, stable image quality can be maintained over time.

[0011]

As described above, according to the present invention, a differential drive mechanism using a wire (belt) and a pulley to move the second traveling body at half the speed of the first traveling body. At the time of driving by a wire, the parallelism between the second traveling body and the first traveling body is reduced due to dust and the like adhering and accumulating in the outer peripheral groove of the pulley provided on the second traveling body. It is possible to solve the problem that the image quality of the result reading is reduced. That is, in the image reading device of the first aspect, since the cleaning member is always in contact with a portion of the outer peripheral groove of the second traveling body pulley where the wire is not hung, the outer peripheral groove of the second traveling body pulley accumulates. The dust can be removed, and the dimension of the second traveling body pulley does not change apparently, and a stable image quality can be maintained over time. In the image reading apparatus according to the second aspect, since the cleaning member rotates together with the second traveling body pulley, dust that accumulates in the outer peripheral groove of the second traveling body pulley can be increased without increasing drive load or lacking stability. Can be removed. In the image reading apparatus according to the third aspect, since the one-way clutch is mounted at the center of the rotatably supported cleaning member, there is an increase in driving load and a lack of stability when moving the traveling body for reading. Thus, dust accumulated in the outer peripheral groove of the second traveling body pulley can be more reliably removed.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of an image reading apparatus as one embodiment of the present invention.

FIG. 2 is a perspective view of a main part of FIG. 1 (schematic diagram of a traveling body drive system).

FIG. 3 is an exploded perspective view showing a structure for supporting a pulley.

FIG. 4 is an exploded perspective view showing another structure for supporting a pulley.

FIGS. 5A and 5B are a front view of a main part showing a configuration of an embodiment of the present invention, and a perspective view of a cleaning member support plate.

FIGS. 6A and 6B are a front view of a main part and an exploded perspective view of a main part showing a configuration of another embodiment of the present invention.

7 (a) and 7 (b) are a front view of a main part and an exploded perspective view of a main part showing a configuration of another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Housing, 2, 3, 4, 5 Side wall, 6 First running body, 7
Second traveling body, 8 image reading units, 10 light sources, 11 mirrors, 12 carriages, 13a, 13b
Mirror, 14 carriage, 15 traveling body pulley (idler pulley), 15A outer peripheral groove, 16 drive shaft, 17
Drive pulley, 19 Drive motor, 20, 21 Turn pulley on housing side, 22 Wire, 40 Cleaning member, 41
Support plate, 45 cleaning members, 46 shafts, 50 cleaning members, 5
1 One-way clutch.

Claims (3)

[Claims] 1. A light source for irradiating light to a document surface set at a predetermined position, a first traveling body that moves by supporting an optical component for guiding reflected light of the document in a predetermined direction, and supports the optical component. A second traveling body that moves at a predetermined speed, a traveling body pulley rotatably supported by the second traveling body, and a wire wound around the traveling body pulley. And a driving mechanism that drives at a speed difference of: 2. The cleaning member that contacts a region of the groove formed on the outer peripheral surface of the pulley where the wire is not wound around the driving member, is disposed on the second traveling body. An image reading apparatus, comprising: 2. The cleaning member is a roller-like member rotatably supported by a second traveling body around a center portion as a center of rotation, and is rotated by rotation of a traveling body pulley. Item 2. The image reading device according to Item 1. 3. A one-way clutch is provided at the center of the roller-shaped cleaning member, and the cleaning member is configured to rotate only following rotation of the traveling body pulley in one direction. The image reading device according to claim 2.