JPH11122427A - Picture reading unit and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture reading unit in which a unit main body can be miniaturized by always holding a parallel interval between a transparent board and a unit main body to be constant. SOLUTION: A picture reading unit is arranged on the lower face of a transparent board A on which a reading original is placed so as to be faced to it, and moved in parallel along the transparent board A in an arrow M shown in a figure, and a picture is optically fetched through a condenser lens 7 provided at a unit main body 1. In this case, the unit main body 1 is provided with a roller 2 rotated in contact with the lower face of the transparent board A when this picture reading unit is moved in parallel along the transparent board A, and the main body 1 is energized to the transparent board A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading unit that optically captures an image while moving in parallel along the lower surface of a transparent plate on which a document to be read is placed, and a flat bed type using this image reading unit. The present invention relates to an image reading device.

[0002]

2. Description of the Related Art Heretofore, as this type of image reading apparatus, there has been known an image reading apparatus which reads an image of a read document in a so-called flat bed format. It has a reading unit. The image reading unit optically captures an image by receiving light reflected on a read document by an image sensor provided in the unit body. When reading is performed using such an image reading unit, the unit body is moved in parallel along the transparent plate in conjunction with a wrapping belt mechanism or the like. Further, in a flat-bed type image reading apparatus, since an image is generally read by a line scanning method, the unit main body is formed in a longitudinal shape that is horizontally long in the moving direction, and in a longitudinal direction of the unit main body. An image reading line of the image sensor is formed along the line.

In such an image sensor of the unit main body, a condensing lens for converging light reflected on a read original to a light receiving element is incorporated. This kind of condensing lens has one characteristic as a characteristic. The focal point has a limit range (hereinafter, referred to as a depth of focus) at which a clear image can be formed before and after the focal point. Therefore, it is desirable that the parallel distance between the transparent plate and the unit main body is constant at any moving position, whereby the parallel distance between the transparent plate and the unit main body is adjusted to be constant. On the other hand, when the unit body moves in parallel along the transparent plate, due to the mounting tolerance and deformation tolerance of the transparent plate and the unit body,
Because the parallel spacing fluctuates slightly, locally,
As the condenser lens incorporated in the image sensor, a lens having a large depth of focus is adopted, and an optical path system having a long focal length is necessarily set in the unit body.

[0004]

However, in the above-mentioned conventional image reading apparatus, a depth of focus is used as a condensing lens for converging light to a light receiving element of an image sensor by a mounting tolerance or a deformation tolerance of a transparent plate and a unit body. Since the optical path system with a long focal length is inevitably set in the unit body,
This has led to an increase in the size of the unit body itself and, in turn, an increase in the size of the entire image reading apparatus. That is, when the unit body moves in parallel along the transparent plate, the parallel interval between the two should be kept constant, but the optical path system from the read original to the light receiving element of the image sensor must be large. Accordingly, there is a need to increase the size of the unit body and the entire apparatus.

The present invention has been devised in view of the above circumstances, and when the unit main body moves in parallel along the transparent plate, the parallel distance between the transparent plate and the unit main body is always kept constant. Accordingly, it is an object of the present invention to provide an image reading unit capable of reducing the size of a unit main body and, consequently, the size of the entire image reading device, and a flat bed type image reading device using the image reading unit.

[0006]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, the image reading unit provided according to the first aspect of the present invention is disposed to face the lower surface of a transparent plate on which a read original is placed, and moves parallel to the transparent plate while attaching to the unit body. An image reading unit that optically captures an image by the provided optical system means, and when moving in parallel along the transparent plate, a roller that rotates in contact with the lower surface of the transparent plate is provided in the unit main body, The unit body is biased against the transparent plate.

According to the image reading unit provided by the first aspect in which the above technical means are taken, when the unit main body moves in parallel along the transparent plate, the roller provided on the unit main body is always transparent. It rotates while being in contact with the lower surface of the plate, and the roller is interposed between the transparent plate and the unit body.Therefore, the parallel spacing between the two is not affected by the mounting tolerance and deformation tolerance of the two. Is always kept constant. Therefore, when the unit main body moves in parallel along the transparent plate, the parallel distance between the transparent plate and the unit main body is always kept constant without slightly changing, so that the optical system means provided in the unit main body is provided. It is possible to reduce the optical path system as small as possible, and it is possible to reduce the size of the unit body by securing the optical path system as small as possible. In addition, since the parallel distance between the transparent plate and the unit main body is always kept constant, the optical image capturing by the optical system means over the entire moving range of the unit main body is stabilized, and the whole image with a constant reading condition is obtained. Can be obtained.

As the unit body, when it moves parallel to the transparent plate, for example, there is one that moves along the longitudinal direction of the transparent plate formed in a rectangular shape, but the moving direction is not particularly limited. .

The unit body is formed of, for example, a resin case. However, the unit body is not limited to the resin case, but may be made of metal or other materials.

The optical means includes, for example, an image sensor having a light receiving element incorporated therein. The light receiving element is fixedly arranged at a position different from the unit main body, and a reflection means for guiding light from the unit main body to the light receiving element. The member may be provided on the unit main body as optical means.

When the moving direction of the unit body is fixed, the roller may be, for example, a cylindrical roller which rotates along the moving direction. However, the roller is not particularly limited to the cylindrical roller, but may be a spherical roller. There may be.

In a preferred embodiment, a plurality of the rollers are arranged along a moving direction of the unit body.

According to such an image reading unit, since a plurality of rollers are arranged along the moving direction of the unit main body, when the unit main body moves in parallel along the transparent plate, the rollers are arranged in the moving direction of the unit main body. Since the parallel distance along the axis is reliably kept constant by the interposition of the plurality of rollers, it is possible to stabilize the capture of an optical image over the entire moving range along the moving direction of the unit body.

[0015] In another preferred embodiment, the unit main body is formed in a longitudinal shape that is horizontally long in the moving direction, and the rollers are arranged in a plurality at regular intervals along the longitudinal direction of the unit main body. Have been.

According to such an image reading unit, the unit main body is formed in a longitudinal shape that is horizontally long in the moving direction, and a plurality of rollers are arranged at regular intervals along the longitudinal direction of the unit main body. When the unit body moves in parallel along the transparent plate, the parallel spacing along the longitudinal direction of the unit body is reliably kept constant by the interposition of a plurality of rollers, so that the unit body is moved in the longitudinal direction of the unit body. It is possible to stabilize the capture of the optical image over the entire reading width along the range.

Further, in another preferred embodiment, the unit main body is formed in a longitudinal shape that is laterally long in the moving direction, and the rollers are disposed only at both ends in the longitudinal direction of the unit main body. .

According to such an image reading unit, the unit main body is formed in a longitudinal shape that is horizontally long in the moving direction, and the rollers are disposed only at both ends in the longitudinal direction of the unit main body. When the parallel movement is performed along the transparent plate, since the roller contacts and rotates at both end positions of the transparent plate facing the both ends in the longitudinal direction of the unit main body, that is, outside the reading width by the optical means, such a roller is used. A trouble in reading is prevented without leaving a contact mark or a rotational scratch on the reading surface of the transparent plate.

Further, in another preferred embodiment, the roller is supported by the unit main body via a bearing.

According to such an image reading unit, since the roller is pivotally supported by the unit main body via the bearing, when the unit main body moves in parallel along the transparent plate, the roller comes into contact with the transparent plate. Is rotated smoothly, so that the parallel movement of the unit body with respect to the transparent plate can be performed smoothly.

Further, in another preferred embodiment, the optical means comprises an image sensor having a light receiving element.

According to such an image reading unit, since the optical means comprises an image sensor having a light receiving element, it is only necessary to secure an optical path system to the image sensor in the unit main body, and the optical path extends to outside the unit main body. Since there is no need to secure a system, it is possible to reduce the size of the entire image reading apparatus.

Further, in another preferred embodiment, the image sensor includes a condenser lens that condenses and guides reflected light reflected by the read original and transmitted through the transparent plate to a light receiving element. .

According to such an image reading unit, the image sensor is provided with the condensing lens for guiding the reflected light reflected by the read original and transmitted through the transparent plate while converging the light to the light receiving element. Since the parallel distance between the plate and the unit body is always kept constant, it is possible to adopt a so-called condensing lens with a small depth of focus. As a result, it is only necessary to secure an optical path system with a short focal length in the unit body. Thus, the size of the unit body can be reduced. In addition, the use of a condenser lens having a small depth of focus results in an improvement in optical performance, so that a sharper image can be obtained.

Examples of the condensing lens include a spherical lens and an aspherical lens such as a convex lens and a rod lens. However, the present invention is not particularly limited thereto, and other types of condensing lens may be used.

Further, in another preferred embodiment, the image sensor includes an irradiation light source and a light guide member that guides the irradiation light of the irradiation light source to the read original while transmitting the irradiation light of the irradiation light source through the transparent plate. ing.

According to such an image reading unit, the image sensor includes an irradiation light source and a light guide member that guides the irradiation light from the irradiation light source to the read original while transmitting the irradiation light through the transparent plate. Because
Since the parallel distance between the transparent plate and the unit body is always kept constant, the amount of light guided from the irradiation light source to the read original via the light guide member is constant, and the optical performance is improved. Images can be obtained.

Examples of the irradiation light source include a cold cathode tube and an LED, but are not particularly limited thereto, and other types of irradiation light sources may be used.

An image reading apparatus provided by the second aspect of the present invention reads an image of a read original in a flat bed format using the image reading unit provided by the first aspect of the present invention. It is characterized by.

According to the image reading apparatus provided by the second aspect in which the above technical means are employed, by using the image reading unit exhibiting the above-described excellent effects, the image of the read original can be read in a flat bed format. As a result, it is needless to say that such an effect of the image reading unit itself can be enjoyed, and furthermore, a drive system for moving the unit main body and the like can be downsized, and the whole image reading apparatus can be downsized.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view, partly in section, showing an image reading unit according to a first embodiment of the present invention.
2 is an exploded perspective view of a main part of the image reading unit shown in FIG. 1, FIG. 3 is an external plan view showing the image reading unit shown in FIG. 1 from above, and FIG. 4 is an image reading unit shown in FIG. FIG. 5 is a side view of the appearance showing
FIG. 2 is a cross-sectional view showing a XX cross section of FIG. 1.

In these figures, this image reading unit is used in a flat bed type image reading apparatus, and its unit body 1 is arranged opposite to the lower surface of a transparent plate A on which a document to be read is placed. While translating along the transparent plate A in the direction indicated by the arrow M in the figure,
The image is optically captured by an image sensor described later in the unit body 1. Here, the unit main body 1 is connected to a not-shown wrapping belt mechanism, and the wrapping belt mechanism is circulated by a driving force of a stepping motor or the like, so that the unit main body 1 is located inside the image reading apparatus housing. Although it is configured to move along the slide rail, such a wrapping belt mechanism is conventionally known, and thus a detailed description thereof is omitted. In this image reading apparatus, a line scanning method which is a general image sensor reading method in this type of flatbed type is applied.

The transparent plate A is made of, for example, glass.
It is attached and fixed to the upper surface of a casing of an image reading device (not shown), and is formed in a rectangular shape with a predetermined thickness with a direction indicated by an arrow W in the drawing as a short side. A document to be read is placed on the transparent plate A in such a manner that the surface to be read faces downward.

As shown in FIG. 2, the components incorporated in the image reading unit include a unit body 1, a plurality of rollers 2, a cover plate 3, a cold cathode tube 4, a reflector 5, a shield member 6, and a condenser lens 7. And a circuit board 8 on which a plurality of light receiving elements 8a are mounted. Such a cold cathode tube 4, a reflector 5, a shield member 6, a condenser lens 7, and a circuit board 8 are main components of the image sensor, and other circuits such as an inverter (not shown) are also incorporated as components of the image sensor. Have been.

The unit main body 1 is a case made of, for example, a synthetic resin, and is movable in a direction indicated by an arrow M in FIG. It is formed in a horizontally long shape, that is, a shape whose longitudinal direction is the direction indicated by the arrow W in the figure. As shown in FIG. 5 in particular, such a unit main body 1 has an arrow M in FIG.
And a roller 2 to be described later is interposed in the parallel interval PT, so that the roller 2 is slightly urged against the lower surface of the transparent plate A and is not shown. They are opposed to each other while being supported by slide rails. Here, the parallel interval PT is a length from the lower surface of the transparent plate A to the light incident surface 7a of the condenser lens 7 described later. As shown in FIG. 3, concave portions 1 a for fitting the rollers 2 are formed along the longitudinal direction W at regular intervals WT on the surface facing the transparent plate A of the unit main body 1 in three divided portions. As shown in FIG. 2, a pinhole 1b for supporting the roller 2 is formed on the inner surface of the concave portion 1a. As shown in FIG. 3, the concave portions 1a formed at both ends in the longitudinal direction W of the unit main body 1 and the concave portions 1a formed at the divided positions near the central portion are arranged in the moving direction M of the unit main body 1. Are arranged so as to be at a constant interval MT along. Further, the unit body 1 includes
As shown in FIG. 2, a first opening-shaped first housing for accommodating a cold cathode tube 4, a reflector 5, and a shield member 6 described later.
Is formed, and the condenser lens 6 is formed.
Is formed, and a circuit board 8 to be described later is joined to the lower surface side of the unit body 1.

The roller 2 is a cylindrical rolling element made of rubber, for example, and has a concave portion 1 a formed in the unit main body 1.
When the shaft 2a is supported by the pinhole 1b, the unit 2 is fitted so that the rotation direction is the moving direction M of the unit body 1. In a state in which the roller 2 is fitted in the concave portion 1a and the unit main body 1 is arranged to face the transparent plate A, a part of the outer peripheral surface of the roller 2 always contacts the lower surface of the transparent plate A as shown in FIG. The roller 2 in such a state is rotatable with the parallel movement of the unit body 1 with respect to the transparent plate A. That is, when the unit main body 1 moves in parallel along the transparent plate A, the roller 2 is interposed in the parallel space PT between the transparent plate A and the unit main body 1, and the transparent plate A and the unit main body 1 The parallel space PT is always kept constant without being affected by the mounting tolerance and the deformation tolerance.

The cover plate 3 is a transparent plate made of, for example, a synthetic resin.
c It is attached so as to close the upper surface opening. As a result, the cold cathode tube 4, the reflector 5, and the like, which will be described later, are covered by the cover plate 3, and the irradiation light from the cold cathode tube 4 and the reflected light from the reflector 5, as shown in FIG. It is possible to reach the image reading position P on the transparent plate A while transmitting the light.

As shown in FIG. 5, the cold-cathode tube 4 is used as an irradiation light source for irradiating a desired image reading position P with light, and has a substantially full length area excluding electrode portions at both ends in the longitudinal direction. Irradiate white light from the light emitting surface of.

The reflector 5 has a function as a light guiding member for efficiently guiding the irradiation light from the cold cathode tube 4 to the image reading position P, and also has a function to support the cold cathode tube 4 itself. The reflector 5 has a length substantially equal to that of the cold-cathode tube 4, and has a uniform cross-sectional shape at various points in the longitudinal direction. Further, as shown in FIG. 5, the reflector 5 is formed with a concave light source accommodating portion 5a for accommodating the cold cathode tube 4, and the cold cathode tube 4 accommodated in the light source accommodating portion 5a. Irradiation light can reach the image reading position P through the aperture surface. On the other hand, the reflected light emitted from the cold cathode tube 4 and reflected on the inner wall surface 5b of the light source housing 5a can reach the image reading position P through the opening surface. 5b is a white light reflecting surface so as to reflect light efficiently.

The shield member 6 is formed by pressing a metal plate or the like, and has a length substantially equal to that of the cold cathode tube 4 and the reflector 5. The shield member 6 is accommodated in the first accommodating portion 1c of the unit body 1 in a state where the shield member 6 is assembled integrally with the cold cathode tube 4 and the reflector 5.

The condensing lens 7 is for converging the light reflected at the image reading position P based on the light emitted from the cold cathode tube 4 to a plurality of light receiving elements 8a on a circuit board 8, which will be described later. For example, a so-called Selfoc lens array in which aspherical rod lenses capable of converging an image of a read document at an erect equal magnification are arranged along the longitudinal direction M of the unit body 1 is applied. Such a condenser lens 7
As described above, since the parallel distance PT between the transparent plate A and the unit main body 1 is always kept constant, a so-called relatively small focal depth is adopted. As a result, as shown in FIG. As described above, the incident optical path L1 from the image reading position P, which is the focal length, to the light incident surface 7a and the exit optical path L2 from the light exit surface 7b to the light receiving element 8a are relatively short, so that a general flat bed type A short optical path system L is ensured as the image reading device. Also,
The condenser lens 7 is incorporated in a state of being fitted into a second housing portion 1d formed in the unit main body 1, and is located substantially directly above the light incident surface 7a of such a condenser lens 7. The surface portion of the transparent plate A is the image reading position P.

The circuit board 8 is joined to the lower surface of the unit body 1 with the light receiving element 8a on the board positioned substantially directly below the condenser lens 7.
The light converged by the light receiving element 8a is photoelectrically converted by the light receiving element 8a, so that an image signal having a voltage value corresponding to the amount of received light is captured. The captured image signal is output to a control unit (not shown) outside the unit main body 1 through a flexible wiring cord (not shown) via a connector terminal 8b provided on the circuit board 8. A plurality of such light receiving elements 8a are arranged along the longitudinal direction of the circuit board 8 according to the line scanning method of the image sensor.

In the above configuration, the operation and effect at the time of reading will be described with reference to FIG.

First, when the unit main body 1 is translated along the transparent plate A in the direction of arrow M in FIG.
Light from the reflector 5 is guided to the image reading position P, and light reflected at the image reading position P is focused on the light receiving element 8a via the condenser lens 7. That is, the image of the read document is optically continuously captured while the unit main body 1 moves parallel to the transparent plate A.

At this time, while the rollers 2 arranged in the unit body 1 are always rotating while being in contact with the lower surface of the transparent plate A, the rollers 2 are interposed in the parallel space PT between the transparent plate A and the unit body 1. As a result, no matter where the unit body 1 is located in the movement direction M, the parallel space PT is always kept constant, and any part of the unit body 1 along the longitudinal direction W is The state is kept constant with respect to the transparent plate A.

Here, assuming that there is no roller 2, the incident optical path L1 from the image reading position P to the light incident surface 7a of the condenser lens 7 may fluctuate due to the following factors. . The factors include the influence of the relative displacement of the unit body 1 with respect to the transparent plate A due to the mounting tolerance, the influence of the curved deformation of the transparent plate A itself due to the deformation tolerance, the influence of the local thickness difference of the transparent plate A, the transparency. Influence of a focal displacement caused by a refractive index that varies according to the thickness of the plate A, and the like.

Therefore, the unit main body 1 is
In the state where is always kept at a constant parallel interval PT with respect to the transparent plate A, it is not possible to exclude the influence based on the thickness tolerance of the transparent plate A described above, but it is affected by the mounting tolerance and the deformation tolerance. You will not get it. The reason is clear from the fact that the unit main body 1 is translated while being urged against the transparent plate A via the roller 2, that is, the unit main body 1 is not displaced relative to the transparent plate A itself. It is possible to capture images without being affected by mounting tolerances and deformation tolerances while moving in parallel along the curved and deformed shape of.

Therefore, when the unit main body 1 translates along the transparent plate A, the parallel distance PT between the transparent plate A and the unit main body 1 is always kept constant without slight fluctuation. By using the condenser lens 7 having a small focal length and a short focal length, the image reading position P
It is possible to reduce the optical path system L from the optical path L to the light receiving element 8a as small as possible. By keeping the optical path system L small, it is possible to reduce the size of the unit main body 1 and the overall size of the image reading apparatus.

Further, since the parallel space PT between the transparent plate A and the unit main body 1 is always kept constant, the parallel distance PT in the entire moving range along the moving direction M of the unit main body 1 and the longitudinal direction W of the unit main body 1 Along the entire reading width along,
An optical image is stably captured by the image sensor, and an entire image with a constant reading condition can be obtained.

Further, by employing the condenser lens 7 having a small depth of focus, the optical performance is improved, so that a sharper image can be obtained.
Even when the amount of light guided to the read original via the reflector 5 from the light source is constant, the optical performance is improved, so that a clearer image can be obtained.

Further, as another example of the first embodiment, there is an image reading unit as shown in FIGS. Note that this image reading unit is the first
Since it has almost the same configuration as the image reading unit according to the embodiment, only the characteristic portions will be described.

In the image reading unit shown in FIGS. 6 and 7, a bearing holder 10 for supporting the roller 12a is joined to both ends of the unit body 11 in the longitudinal direction W via bearings (not shown). Near the center of the main body 1 in the longitudinal direction W, a roller 12
The roller support member 19 that supports the b in a state of being fitted into the concave portion 19a is joined. In addition, such a bearing holder 10 and a roller supporting member 19 are attached to the unit body 11.
It is not necessary to provide the unit separately, and it may be formed integrally with the unit main body 11. The roller 1 supported by the bearing holder 10 and the roller support member 19
2a and 12b are supported at a higher position than the roller 2 according to the above-described first embodiment. Therefore, the parallel distance PT1 between the transparent plate A and the unit body 11 is increased.
Are kept slightly large as shown in FIG. As shown in FIG. 6, the rollers 12a and 12b supported by the bearing holder 10 and the roller support member 19 are fixed at intervals M along the moving direction M of the unit body 11.
They are arranged so as to be T1. Roller 12
a and 12b are arranged at regular intervals WT1 along the longitudinal direction W of the unit body 11.

Therefore, according to the image reading unit having such a configuration, since the rollers 12a and 12b are arranged in three rows along the moving direction M of the unit main body 11, the unit main body 11 is arranged along the transparent plate A. When the unit body 11 is moved in parallel, the parallel interval PT1 along the moving direction M of the unit main body 11 is surely kept constant by the interposition of a number of rollers 12a and 12b. The capture of an optical image over the entire moving range can be further stabilized.

The rollers 12a disposed at both ends in the longitudinal direction W of the unit main body 11 are supported by the bearing holder 10 via bearings (not shown). When the unit 12 is moved in parallel, the smooth rotation of the roller 12a allows the unit body 11 to be moved in parallel with the transparent plate A smoothly.

Next, a description will be given of a second embodiment of the image reading unit according to the present invention.

FIG. 8 is an external plan view showing the image reading unit according to the second embodiment from above, and FIG. 9 is an external side view showing the image reading unit shown in FIG. 8 from the side. Since the image reading unit shown in FIG. 2 has substantially the same configuration as that of the first embodiment, only the characteristic portions will be described.

The image reading unit shown in FIGS. 8 and 9 has substantially the same configuration as the image reading unit shown in FIGS. 3 and 4, except that the roller 22 is arranged in the longitudinal direction of the unit body 21. It is in a state of being arranged only at both ends of W. Further, the rollers 22 arranged only at both ends in the longitudinal direction W are arranged in two rows at a constant interval MT2 along the moving direction M of the unit body 21, as shown in FIG.

In such an image reading unit, when the unit body 21 moves in parallel along the transparent plate A, the transparent plate A opposing the both ends of the unit body 21 in the longitudinal direction W is used.
, Ie, the roller 22 comes into contact with the outside of the reading width A1 of the image via the condenser lens 27 and the cover plate 23 and rotates. Here, as in the image reading unit according to the first embodiment, the case where the rollers 2 arranged at positions other than both ends in the longitudinal direction W of the unit main body 1 rotate by contacting the image reading surface of the transparent plate A In addition, there is a possibility that contact marks and rotational scratches by the roller 2 may remain on the reading surface due to long-term use.

On the other hand, in the image reading unit according to the second embodiment, since the rollers 22 are disposed only at both ends in the longitudinal direction W of the unit main body 21, the unit main body 21 is parallel to the transparent plate A. When moving, the roller 22 comes into contact with the outside of the reading width A1 of the image via the condensing lens 27 and the cover plate 23 and rotates. Disturbance in reading an optical image is prevented without leaving it on the reading surface.

Further, as another example of the second embodiment, there is an image reading unit as shown in FIGS. 10 and 11, and this image reading unit is basically the same as that of the second embodiment. It has a configuration.

That is, the image reading unit shown in FIGS. 10 and 11 has substantially the same configuration as the image reading unit as shown in FIGS. 6 and 7, but has both ends in the longitudinal direction W of the unit body 31. The roller 32 is rotatably supported via the bearing holder 30 only in the portion, and such a roller 32 is configured to rotate in contact with the outside of the image reading width A1.

Therefore, it goes without saying that the effect of the second embodiment as described above can be enjoyed by such an image reading unit.

As another example of the second embodiment, there is an image reading unit as shown in FIGS. 12 and 13. In this image reading unit, instead of the bearing holder 30, a roller holder 40 is provided. It is attached to both ends in the longitudinal direction W of the unit main body 41 via fastening members 40a such as. A roller 42 is rotatably supported on the support shaft 40b of the roller holder 40 projecting in the longitudinal direction W of the unit body 41. Even with such an image reading unit, the roller 42 is located outside the image reading width A1. Since the contact and rotation are performed, it is possible to enjoy the effects of the second embodiment as described above.

[Brief description of the drawings]

FIG. 1 is a first view of an image reading unit according to the present invention.
FIG. 2 is a perspective view of a partial cross-sectional appearance showing the embodiment.

FIG. 2 is an exploded perspective view of a main part of the image reading unit shown in FIG.

FIG. 3 is an external plan view showing the image reading unit shown in FIG. 1 from above.

FIG. 4 is an external side view showing the image reading unit shown in FIG. 1 from a side.

FIG. 5 is a sectional view showing a section taken along line XX of FIG. 1;

FIG. 6 is an external plan view showing an image reading unit as another example of the first embodiment as viewed from above.

7 is an external side view showing the image reading unit shown in FIG. 6 from the side.

FIG. 8 shows a second example of the image reading unit according to the present invention.
It is an external appearance side view which showed embodiment of FIG.

9 is an external side view showing the image reading unit shown in FIG. 8 from the side.

FIG. 10 is an external plan view showing an image reading unit as another example of the second embodiment from above.

11 is an external side view showing the image reading unit shown in FIG. 10 from the side.

FIG. 12 is an external plan view showing an image reading unit as another example of the second embodiment from above.

13 is an external side view showing the image reading unit shown in FIG. 12 from the side.

[Explanation of symbols]

 1, 11, 21, 31, 41 Unit body 2, 12, 22, 32, 42 Roller 3, 13, 23, 33, 43 Cover plate 4 Cold cathode tube 5 Reflector 7, 17, 27, 37, 47 Condensing lens Reference Signs List 8 circuit board 8a light receiving element 10, 30 bearing holder 19 roller support member 40 roller holder

Claims (9)

[Claims] 1. An image reading unit disposed opposite to a lower surface of a transparent plate on which an original to be read is placed, and taking an image optically by an optical system provided in a unit body while moving in parallel along the transparent plate. When the parallel translation along the transparent plate, provided in the unit body a roller that rotates in contact with the lower surface of the transparent plate,
An image reading unit, wherein the unit main body is urged against the transparent plate. 2. The image reading unit according to claim 1, wherein a plurality of the rollers are arranged along a moving direction of the unit main body. 3. The unit body according to claim 1, wherein the unit body is formed in a longitudinal shape that is horizontally long in the moving direction, and the rollers are arranged in a plurality at regular intervals along the longitudinal direction of the unit body. Item 3. The image reading unit according to Item 2. 4. The unit according to claim 1, wherein the unit main body is formed in a longitudinal shape that is horizontally long in a moving direction, and the rollers are disposed only at both ends in the longitudinal direction of the unit main body. An image reading unit as described. 5. The image reading unit according to claim 1, wherein the roller is supported by the unit body via a bearing. 6. The image reading unit according to claim 1, wherein said optical system means comprises an image sensor having a light receiving element. 7. The image reading device according to claim 6, wherein the image sensor includes a condenser lens for guiding the reflected light reflected by the read document and transmitted through the transparent plate to a light receiving element while converging it. unit. 8. The image sensor according to claim 6, further comprising an irradiation light source, and a light guide member that guides the irradiation light of the irradiation light source to the read original while transmitting the irradiation light through the transparent plate. 8. The image reading unit according to 7. 9. An image reading apparatus using the image reading unit according to claim 1 to read an image of a document to be read in a flat bed format.