JP3422562B2 - Image reading device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus capable of reading original image data as an image input apparatus used in facsimiles, digital copying machines, scanners and the like.

[0002]

2. Description of the Related Art In recent years, a one-dimensional self-scanning line image sensor for scanning the image data of an original by scanning an optical carriage in the sub-scanning direction as an image input means for a facsimile machine, an electronic filing device, etc., including a digital copying machine. As a result, image reading apparatuses that can sequentially read each line have become mainstream.

In these apparatuses, the original is illuminated by the light source, and the diffuse reflection light of the illuminated original is imaged on the line image sensor using the imaging lens to read the original. The brightness of the original and the stability of the brightness are important.

A conventional image reading apparatus will be described below with reference to FIGS. 8 and 9. 8 is a schematic configuration diagram of a conventional image reading apparatus, and FIG. 9 is a schematic enlarged configuration diagram of the first carriage 55a shown in FIG. In FIGS. 8 and 9, 51 is an image reading apparatus main body, 2 is a document glass on which a document is placed, 3 is a document cover for bringing the document into close contact with the document glass 2, and 4 is a white reference plate which is a white reference of the document. It is attached to the image reading apparatus main body 1.

Reference numeral 55a is a first carriage for scanning and reading a document. In the first carriage 55a,
Reference numeral 6 is a light source for irradiating the original, and 7 is a first reflecting mirror that bends the optical path by 90 ° in order to guide diffused reflected light from the original to a line image sensor 12 (described later), and each is fixed to the first carriage 55a. . Reference numeral 17 denotes an original document aperture, which directly or directly reflects the diffused reflected light or other stray light of a portion of the original illuminated by the light source, which is an area on the original that is not read. Line image sensor 12 after being reflected
To prevent the incident.

Reference numeral 8a denotes a second carriage, and the second carriage 8a is provided with an optical path 9 for the reflected light from the first reflecting mirror 7.
Second reflection mirror 9 that bends at 0 °, and second reflection mirror 9
A third reflecting mirror 10 that bends the optical path of the reflected light from 90 degrees is fixed. Reference numeral 11 is an image forming lens for forming an image of the original on the line image sensor 12, and reference numeral 12 is a line image sensor for converting the image of the original formed by the image forming lens 11 into an electric signal.

Reference numeral 56a denotes an optical path of diffused / reflected light from the original that reaches the line image sensor 12 through the optical axis of the imaging lens 11, 13 is a supporting member for the first carriage 55a and the second carriage 8a, and 14 is a first carriage. 55 is a support roller, and 15 is a support roller for the second carriage 8a. The first carriage 55a and the second carriage 8a can be moved along the support member 13 by rotating or rotating the support rollers 14 and 15 on the support member 13 in the document reading direction. Also, 58
Is a light source unit that is configured integrally with the first carriage 55a and to which the light source 6 that illuminates the document surface is attached.

Next, with reference to FIGS. 8 and 9, the operation of the image reading apparatus configured as described above will be described. First, when a document reading command is issued from an external host (not shown), the light source 6 is turned on, a carriage drive motor (not shown) is rotated, and a first power is transmitted through a power transmission mechanism (not shown). The carriage 55a and the second carriage 8a are moved simultaneously. This power transmission mechanism (not shown) is set such that the moving distance of the second carriage 8a is half the moving distance of the first carriage 55a, and the optical path is set no matter where the first and second carriages 55a and 8a move. The optical path length of 56a is always constant.

For example, in FIG. 8, the first carriage 5
When 5a moves to the rightmost position 55b, the second carriage 8a moves half the distance from the position of the first carriage 55a to the position 55b.
Since it will move to b, the optical path 5 when moving
The optical path length of 6b is equal to the optical path length of the optical path 56a before moving. Therefore, the first carriage 55a is located at the position 55b.
Even while moving to, the optical path length is constant. Thus, the first carriage 55a and the second carriage 8a
A reading method in which the and are moved at the same time and the original is read while maintaining the above relationship is generally called a mirror moving method. Hereinafter, an image reading apparatus using the mirror moving method will be described.

Next, the image reading operation by the above image reading device will be described. In the image reading apparatus configured as described above, first, when the first carriage 55a reaches the position of the white reference plate 4, the white reference plate 4 is illuminated by the light source 6. The diffuse reflection light is reflected by the first reflection mirror 7, the second reflection mirror 9, and the third reflection mirror 10, respectively,
An image is formed on the line image sensor 12 by the image forming lens 11, converted into a white level electric signal, and the data obtained by the conversion serves as a white reference of the original.

Next, when the first carriage 55a reaches the original reading start position, the reading of the original is started. The diffusely reflected light of the document emitted from the light source 6 passes through the first, second and third reflection mirrors 7, 9 and 10 and is imaged on the line image sensor 12 by the imaging lens 11 for one line. Image is converted into an electrical signal. As the first carriage 55a scans, the original is read line by line and converted into an electric signal.
When reaches the reading end position of the document, image data of the entire document is obtained.

[0012]

However, the conventional image reading apparatus as described above has the following problems. In order to improve gradation in an image reading apparatus, it is generally necessary that the electric signal obtained by the line image sensor be sufficiently large within a range having linearity. When the line image sensor has the same sensitivity, the magnitude of the electric signal is determined by the amount of light incident on the line image sensor. Therefore, the amount of light incident on the line image sensor may be increased. If all other conditions are constant, in order to increase the amount of light incident on the line image sensor, place the light source as close to the original as possible so that the angle of incidence with respect to the original glass does not exceed the critical angle. It is necessary to increase (illuminance).

In recent years, in the case of a thin fluorescent tube used to miniaturize the apparatus, since the absolute light amount is small, the light source layout needs to bring the light source closer to the document surface. . However, as described above, in the configuration of the conventional image reading apparatus, the distance between the original glass and the first carriage is not always constant due to the influence of the attachment accuracy of the original glass and the flatness of the original glass itself.

Further, when a document is placed on the document glass, or when a heavy book is placed on the document glass, the document glass and its supporting member may be deformed and the parallelism may be lost. In consideration of the variation in the distance between the original glass and the first carriage and its change, it is necessary to provide a gap of 1 to 3 mm or more between the original glass and the first carriage. Moreover, in the conventional image reading apparatus as described above, since the light source is fixed to the first carriage, the distance between the light source and the document is naturally long, and the light amount is insufficient with a small light source, so that the document is not scanned. There is a problem that the illuminance on the surface cannot be increased.

Further, in the conventional structure as described above, it is difficult to keep the distance between the light source and the document constant when the carriage moves in the sub-scanning, and as the sub-scanning position moves,
There was a problem that the illuminance on the document surface fluctuated and stable image data could not be obtained. These problems are particularly remarkable when a thin fluorescent tube is used as described above and a light source layout in which the light source and the original are placed very close to each other is used.

The present invention has been made in view of the above problems, and increases the amount of light by making the distance between the light source and the original document closer to each other, so that the distance between the light source and the original document is increased despite the deformation of the original glass. Even with a small light source that maintains a constant distance, the gradation is high,
An object is to provide an image reading device that can obtain stable image data.

[0017]

In order to achieve the above object, an image reading apparatus according to the present invention scans a document glass on which a document is placed, a light source for illuminating the document, and a document reading range of the document glass. Scanning means, an optical system for forming an image of diffuse reflected light or transmitted light from a document illuminated by a light source, and an image for reading the diffuse reflected light or transmitted light from the document imaged by the optical system arranged in the apparatus body An image reading apparatus having a reading means, wherein the scanning means is provided with a light source holding means for stacking and holding the light source and for holding a constant distance between the light source and the original glass.
A light source holding member to be placed, and the light source holding member
The light source holding member contacting means that comes into contact with the original glass and the light source holding member
Maintain the relative position of the holding member and the scanning means in the scanning direction.
Hold the connecting means and the light source holding member against the original glass.
And a pressing means for urging, and the light source holding means is
By the pressing means that presses the light source holding member against the original glass.
The original glass is deformed and lowered.
The light source holding member contact means and the original glass
And contact with the light source holding member contact means at other places.
Gap adjuster that provides a specified gap between the original glass
It is characterized by including a step .

[0018]

[0019] The image reading apparatus according to the present invention, for achieving the above object, the light source holding member contacting means, times in the scanning direction by the operation of the scanning means in contact with the document glass provided in the light source holding member It is characterized by being a moving guide roller.

Further, in the image reading apparatus according to the present invention, in order to achieve the above object, the light source holding member contacting means is
The sliding member der Rukoto low friction provided on the holding member in which the features.

In the image reading apparatus according to the present invention, in order to achieve the above object, the pressing means for pressing the light source holding member against the original glass is made of metal or organic material between the light source holding member and the scanning means . It is characterized in that an elastic member is provided.

[0022] The image reading apparatus according to the present invention, for achieving the above object, in which the elastic member and wherein the spring, a leaf spring, a sponge or the rubber or Ranaru.

Further, in order to achieve the above object, the image reading apparatus according to the present invention serves as a pressing means for pressing the light source holding member against the original glass, at a position where the light source holding member and the scanning means face each other. The magnets are arranged so that the same poles face each other.

In order to achieve the above-mentioned object, the image reading apparatus according to the present invention is characterized in that the connecting means comprises a guide pin for supporting the pressing means and a guide hole for guiding the guide pin. .

Further, in order to achieve the above-mentioned object, the image reading apparatus according to the present invention is characterized in that the connecting means is composed of the guide surface of the light source holding means and the guide surface of the scanning means which are superposed on each other in the scanning direction. It is what

[0026]

The image reading apparatus according to the present invention is characterized in that the predetermined gap is in the range of 0.1 mm to 0.5 mm in order to achieve the above object.

In short, the image reading apparatus according to the present invention is
In particular, scanning is performed by separating the light source holding member holding the light source from the scanning means for scanning the original reading range of the original glass, and moving the separated light source holding member in the image reading direction while maintaining the relative position to the scanning means. Means, a light source holding member contacting means for contacting the light source holding member with the original glass so as to maintain a constant interval therebetween, and a pressing member which is mounted between the light source holding member and the scanning means and presses the light source holding member against the original glass. It is characterized in that the distance between the light source and the original glass is kept constant.

[0029]

The image reading apparatus according to the present invention is configured as described above, and moves the light source holding member, which is separated from the scanning means and holds the light source, in the image reading direction while holding the relative position to the scanning means, and presses it. The light source holding member is pressed against the original glass by the means, and the light source holding member is brought into contact with the original glass during movement so that the distance between the light source and the original glass is kept constant, whereby the original glass is deformed. Since the light source moves close to the original glass while keeping a constant distance from the original glass, the gap between the light source and the original glass can be minimized, so that the light flux emitted from the light source is efficiently emitted to the original surface. Since the document surface illuminance can be increased, image data with high gradation can be obtained even with a small light source. Moreover, since the gap between the light source and the document glass does not change, the illuminance on the document surface is always kept constant, and stable image data can be obtained.

The image reading apparatus according to the present invention is configured as described above, and further, as a light source holding member contact means for bringing the light source holding member and the original glass into contact with each other, the image reading apparatus is provided in the light source holding member and comes into contact with the original glass for scanning. By disposing the guide roller that rotates in the direction, even if the original glass is deformed,
Since the light source moves close to the original glass while keeping a constant distance, the gap between the light source and the original glass does not change, so that the illuminance on the original surface is always kept constant with a simple configuration and stable image data is obtained. Can be obtained.

The image reading apparatus according to the present invention is configured as described above, and further, as a means for bringing the light source holding member and the original glass into contact with each other, at least one of the light source holding member and the original glass is provided with a low friction sliding member. Since the light source holding member and the original glass are brought into contact with each other with the sliding member interposed therebetween, the light source can be smoothly moved along the original glass, and the gap between the light source and the original glass changes rapidly. Therefore, the illuminance on the document surface is always kept constant with a simple configuration, and stable image data can be obtained.

The image reading apparatus according to the present invention is constructed as described above, and further, the pressing distance by the pressing means for pressing the light source holding member against the original glass is limited so that a predetermined distance is provided between the light source holding member and the original glass. By providing the gap, it is possible to minimize the vibration of the light source holding member from the original glass and obtain stable image data.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The attached drawings, FIG. 1, FIG. 2, FIG. 3, FIG.
An image reading apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 5, 6, and 7. FIG. 1 shows the first of the present invention.
2 is a schematic configuration diagram of the image reading device in the embodiment of FIG. 2, FIG. 2 is an enlarged configuration diagram of a first carriage of the image reading device shown in FIG.
FIG. 3 is a state diagram showing the state of the original placement surface of the original glass and the state where the first carriage has moved, FIG. 4 is a schematic configuration diagram of an image reading apparatus in the second embodiment of the present invention, and FIG. 5 is FIG.
6 is an enlarged configuration diagram of the first carriage of the image reading apparatus shown in FIG. 6, FIG. 6 is a schematic configuration diagram of the image reading apparatus in the third embodiment of the present invention, and FIG. 7 is an enlargement of the first carriage of the image reading apparatus shown in FIG. It is a block diagram.

First, the structure of the image reading apparatus in the first embodiment of the present invention will be described with reference to FIG. In FIG. 1, 1 is an image reading apparatus main body, 2 is a document glass on which a document (not shown) is placed, 3 is a document cover for bringing the document into close contact with the document glass 2, and 4 is a white reference plate which is a white reference of the document. It is used by being attached to the image reading apparatus main body 1.

Reference numeral 5a designates a first portion for scanning and reading an original.
It is a carriage. In the first carriage 5a, 6 is a light source for illuminating the original, and 7 is a first reflecting mirror for bending the optical path by 90 ° to guide diffused reflected light from the original to the line image sensor 12 (described later). In the image reading apparatus main body 1, 8a is a second carriage, and the second carriage 8a includes a second reflection mirror 9 for bending the optical path of the reflected light from the first reflection mirror 7 by 90 degrees, and a second reflection mirror 9 for the second reflection mirror 9. The third reflection mirror 10 that bends the optical path of the reflected light of 90 degrees is fixed.

Reference numeral 11 is an image forming lens for forming an image of the original on the line image sensor 12, and 12 is an image reading means for converting the image of the original formed by the image forming lens 11 into an electric signal. In the example, it is a line image sensor. In addition, in this embodiment, the first, second, and third
The reflection mirrors 7, 9, 10 and the imaging lens 11 form an optical system.

Reference numeral 16a denotes an optical path of diffusely reflected light from the original which reaches the line image sensor 12 through the optical axis of the imaging lens 11, and 13 denotes a supporting member for the first carriage 5a and the second carriage 8a. 14 is the first carriage 5
a is a supporting roller, and 15 is a supporting roller for the second carriage 8a. When the supporting rollers 14 and 15 rotate on the supporting member 13 in the document reading direction, the first carriage 5a and the second carriage 5a. The carriage 8a is the support member 1
It is possible to move along 3. Further, in this embodiment, the first and second carriages 5a and 8a and the support rollers 14 and 15 form a scanning unit.

Next, referring to FIG. 2, the first carriage 5
A will be described. FIG. 2 is an enlarged configuration diagram of the first carriage 5a. In FIG. 2, 2 is a document glass, 5a is a first carriage, 6 is a light source mounted on a light source unit 18 (described later) to illuminate a document, 17 is direct light from the light source, or on the document illuminated by the light source. This is an original document aperture that prevents diffuse reflection light and other stray light of a portion that is not actually read in the area of (2) from entering the line image sensor 12 directly or by being reflected by the first reflecting mirror 7.

Reference numeral 18 denotes a light source unit (light source holding member) separated from the first carriage 5a according to the present invention, 1
9 is a guide pin attached to the light source unit 18, 2
Reference numeral 0 denotes a guide hole formed at a position facing the guide pin 19 of the first carriage 5a, and the guide pin 1 is provided therein.
The first carriage 5a can be moved only in the up-down direction while maintaining the relative position with respect to the first carriage 5a by guiding 9. In this embodiment, the guide pin 19
Also, the light source holding member 18 and the scanning means 5 are provided by the guide holes 20.
A connecting means for holding a relative position with respect to the scanning direction with respect to a, 8a, 14 and 15 is configured.

Further, 21 is a pressing means disposed on the guide pin 19 (in the present embodiment, a coil spring, but a leaf spring, sponge, rubber, or any other elastic member of metal or organic, Alternatively, any other urging means such as a magnet using magnetic force, static electricity or air may be used), and both ends of the magnet may be connected to the first carriage 5a and the light source unit 18, respectively. They are in contact with each other and act to urge the light source unit 18 toward the original glass 2.

Reference numeral 7 denotes a first reflection mirror 22 fixed to the first carriage 5a for reflecting the diffused and reflected light of the document emitted by the light source 6 and bending its optical path by 90 °.
Is a guide roller attached to the light source unit 18 and for guiding the light source unit 18 along the original glass 2.
That is, the light source holding member contacting means.

Next, the operation of the image reading apparatus according to the first embodiment of the present invention configured as described above will be described with reference to FIG. First, when an original reading command is issued from an external host (not shown), the light source 6 is turned on and the carriage drive motor (not shown) is rotated,
The first carriage 5a through a power transmission mechanism (not shown)
And the second carriage 8a is moved at the same time. This power transmission mechanism (not shown) is set so that the moving distance of the second carriage 8a is half the moving distance of the first carriage 5a, and the optical path is set wherever the first and second carriages 5a and 8a move. The optical path lengths of 16a and 16b are configured to be always constant.

For example, in FIG. 1, the first carriage 5
When a moves to the right end position 5b, the second carriage 8
Since a moves from the position of the first carriage 5a shown in the figure to a half of the distance of the position 5b, that is, the position of 8b, the optical path length of the optical path 16a before the movement and the optical path 16 after the movement.
It is equal to the optical path length of b. Therefore, the first carriage 5
Any optical path length during which a moves to position 5b is constant.

When the first carriage 5a reaches the position of the white reference plate 4, the white reference plate 4 is illuminated by the light source 6. The diffuse reflection light is reflected by the first reflection mirror 7, the second reflection mirror 9, and the third reflection mirror 10, respectively, and the imaging lens 11
Then, the image is formed on the line image sensor 12, converted into an electric signal (white level) by the line image sensor 12, and the data obtained by the conversion becomes the white reference of the original.
In addition, since the error of the black level obtained by turning off the light source 6 is generally smaller than the error when the white level is detected,
In this embodiment, only the white level is acquired.

In order to perform more accurate image reading, for example, it is possible to obtain an electric signal of a black level in addition to the white level. Therefore, the light source 6 is turned off and reflected from the first carriage 5a. A method of setting an electric signal obtained by preventing external light from entering the line image sensor 12 through a mirror to a black level, or a black reference plate (not shown)
Is provided in the image reading apparatus main body 1, and an electric signal obtained by reading this black reference plate in the same manner as the white reference plate is used as a black level.

Next, when the first carriage 5a reaches the original reading start position, the reading of the original is started. The diffusely reflected light of the document illuminated by the light source 6 passes through the first, second, and third reflection mirrors 7, 9, 10 and is imaged on the line image sensor 12 by the imaging lens 11 to form one line. The image is converted into an electrical signal. The original is read line by line by the scanning of the first carriage 5a, converted into an electric signal, and when the first carriage 5a reaches the reading end position of the original, image data of the entire original is obtained.

Next, with reference to FIGS. 2 and 3, the operation of the light source unit 18 mounted on the first carriage 5a via the guide pin 19, the guide hole 20, and the coil spring 21 will be described. Ideally, the surface of the original glass 2 on which the original is placed is preferably kept parallel to the first carriage 5a. However, as described above, in reality, the accuracy of attachment of the original glass 2 and the glass itself. The parallelism is not always maintained due to the thickness tolerance, the parallelism accuracy, and the like.

When a document is placed on the document glass 2, the document glass 2 and its supporting member (not shown) are deformed by pressing with a hand or placing a heavy book or the like, and the parallelism is lost. There are times when you are told. That is, considering the extreme state, the original glass 2 may be configured as shown in FIG.

Here, referring to FIG. 3, the first carriage 5 with respect to the original glass 2 in the state shown in FIG.
Consider the case of moving a. Since the first carriage 5a moves for scanning the original when reading the original, the light source unit 18 attached to the first carriage 5a via the guide pin 19 has a coil spring 21.
The original is scanned while being pressed against the original glass 2 by the pressing force of.

Therefore, for example, even if the right side of the document glass 2 is bent upward as shown in FIG. 3, the light source unit 18 follows the surface of the document glass 2 by the pressing force of the coil spring 21. Since the distance between the light source 6 and the document is always kept constant, the light source 6 can be brought close to the document, and the illuminance on the document surface can be increased even with a small light source.

Next, an image reading apparatus according to the second embodiment of the present invention will be described with reference to FIGS. In the present embodiment as well, as in the first embodiment, the distance between the original glass and the light source is shortened and held constant. Figure 4
5 is a schematic configuration diagram of an image reading apparatus according to a second embodiment of the present invention, and FIG. 5 is an enlarged configuration diagram of a first carriage of the image reading apparatus shown in FIG.

In FIG. 4, 2 is a document glass, 5c is a first carriage having a guide surface facing a guide surface of a light source unit 28 (described later) according to the present embodiment, and 6 is a document placed on the light source unit 28. The light source 17 illuminates the direct light of the light source, the diffuse reflected light and the other stray light of the portion of the document illuminated by the light source that is not actually read, or is reflected by the first reflection mirror 7. This is a document aperture that prevents the light from entering the line image sensor 12 by performing, for example.

Next, in FIG. 5, reference numeral 28 denotes a light source unit having a guide surface separated from the first carriage 5c according to the present invention and having a guide surface facing the guide surface with the first carriage 5c, and 23.
The inner surface of the light source unit 28 so that the light source unit 28 can move only in the vertical direction with respect to the first carriage 5c.
The guide surface of the light source unit 28 provided so as to face the outer surface of c, and 24 is the guide surface of the first carriage 5c that faces the guide surface 23 of the light source unit 28 and guides the light source unit 28 in the vertical direction.

Further, 25a is a magnet attached to the light source unit 28, and 25b is the first carriage 5c.
It is a magnet attached to the
The electrodes 5a and 25b are attached so that the poles of the same phase face each other, and act to repel each other and urge the light source unit 28 to the back side of the surface of the original glass 2 on which the original is placed.
Further, reference numeral 26a is a sliding member as a light source holding member contacting means for sliding the light source unit 28 smoothly along the original glass 2 by reducing friction, and 26b guides the light source unit 28 along the scanning direction. This is the guide surface of the original glass 2. The guide surface 26b may be formed by smoothly processing the back surface of the original glass 2 or by coating an appropriate material, or by attaching another member.

In the second embodiment, as can be seen from the above description, the connecting means for holding the relative position of the light source unit 28 and the first carriage 5c in the scanning direction is connected to the guide surface 23 of the light source unit 28 and the connecting means. 1 the guide surface 24 of the carriage 5c, and the light source unit 28 as the original glass 2
The pressing or urging means for pressing against the magnet 25
a and 25b, a means for guiding the light source unit 28 along the original glass 2 is a slide member 26a and a guide surface 26b.
The difference is that it is different from the first embodiment, and its substantial operation is the same as that shown in the first embodiment.
Therefore, detailed description of the operation of this embodiment will be omitted.

However, in the first embodiment, the guide roller 22 is simply used as the means for guiding the light source unit 28 along the original glass 2, and the guide roller 22 is moved directly in contact with the original glass 2. In this embodiment, the sliding member 2
Since 6a is used, the guide surface 26b is provided on the original glass 2 side, which is a little different. Therefore, the light source 6
Can be smoothly moved along the original glass 2 and the gap between the light source 6 and the original glass 2 does not change rapidly, so that stable image data can be obtained.

In the second embodiment, the guide surfaces 23 and 24 for allowing the light source unit 28 to move only vertically with respect to the first carriage 5c are the guide pins 19 and the guide holes in the first embodiment. The sliding member 26a and the guide surface 26b that guide the light source unit 28 along the original glass 2
Can be replaced with a guide roller 22, and the means for pressing or urging the light source unit 28 against the original glass 2 can be replaced by an elastic member such as a coil spring 21 instead of the magnets 25a and 25b. It is possible. In this regard, similarly to the first embodiment, the characteristic means in the second embodiment can be replaced separately.

Next, an image reading apparatus according to the third embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a schematic configuration diagram of an image reading device according to a third embodiment of the present invention, and FIG. 7 is an enlarged configuration diagram of a first carriage of the image reading device shown in FIG. In the present embodiment as well, as in the first and second embodiments, the distance between the original glass 2 and the light source 6 is shortened and kept constant.

However, the basic construction of the image reading apparatus in this embodiment is similar to that of the first embodiment,
The difference is that in the first embodiment, the light source unit 18
While the original glass 2 and the original glass 2 are always in contact with each other via the guide roller 22, a slight gap 27 is provided between the original glass 2 and the guide roller 22 in the third embodiment.

Therefore, almost the same components as those of the first embodiment are used. However, in this embodiment, in order to set the gap 27, the light source unit 18
A gap adjusting means 29 for restricting the upward movement of the light source unit 18 is arranged between the first carriage 5a and the first carriage 5a. As an example of the gap adjusting means 29, for example, a screw adjusting hole 33 is formed in the first carriage 5a, and a screw hole 35 through which a screw loosely passes toward the light source unit 18 is penetrated from there, and the screw 31 is passed through the screw hole 35. It is configured to be screwed into the unit 18. When adjusting the gap 27,
The screw 31 may be rotated to widen or narrow the distance between the light source unit 18 and the first carriage 5a. Although the screw 31 is separately provided in this embodiment, the guide pin 19 may be threaded so as to be used both for guiding the light source unit 18 and for adjusting the gap.

With such a structure, the desired gap 27 is secured, and when the original glass 2 is deformed and lowered, the gap 27 is contracted, and when the guide roller 22 contacts the original glass 2, At that time, the light source unit 18 is first pushed down along the surface of the original glass 2 and thereafter, the distance between the light source 6 and the original glass 2 is kept constant by the guide roller 22.

However, this is only one example of the gap adjusting means 29, and any other method may be used.
For example, the guide roller 22 may be attached so as to be adjustable in the vertical direction, and it is possible to limit the upward movement of the guide pin 19 to have an adjusting function, or the light source unit 18 can be moved downward. A gap adjusting plate provided with a hook on the upper side so as not to move upward may be attached between the light source unit 18 and the first carriage 5a, or by simply fixing both ends of the coil spring 21. Can be achieved.

Next, the operation of the image reading apparatus according to the third embodiment will be described. The difference from the first embodiment of the third embodiment is that a slight gap 27 is formed between the original glass 2 and the guide roller 22. Since it is only provided, the substantial operation is similar to that shown in the first embodiment. But,
As described above, in the first embodiment, the guide roller 22 always rotates on the original glass 2, whereas in the third embodiment, the guide roller 22 normally moves relative to the original glass 2. Although the document glass 2 moves while maintaining the gap 27, the document glass 2 is deformed and contacts the document glass 2 and rotates when it is projected in the direction of the light source unit 18.

Naturally, the light source 6 is provided only for the gap 27.
The distance between the original and the original varies, but by providing the gap 27 between the light source unit 18 and the original glass 2, the light source unit 18 is not carelessly affected by the vibration from the original glass 2. The fluctuation of the light quantity can be practically ignored if the size of the gap 27 is set to about 0.1 mm to 0.5 mm.

Although not particularly mentioned in the above description, the present invention can be applied to both monochrome and color image reading apparatuses. Further, it is possible to implement an image reading apparatus in which a light source and a reflecting mirror, as well as an imaging lens and a line image sensor are all mounted in one carriage.

[0066]

The image reading apparatus according to the present invention is configured as described above, and in particular, the light source unit for mounting the light source is separated from the first carriage for scanning the original reading range of the original glass, and the guide roller or The light source unit is moved in contact with the original glass by a sliding member or the like, and the light source unit is pressed against the original glass by the elastic member while maintaining the relative position of the light source unit and the first carriage. Since the light source can move close to the original glass even if the original glass is deformed, the gap between the light source and the original glass can be kept constant even if the original glass is deformed. By making it possible to minimize, the light flux emitted from the light source can be efficiently irradiated to the document surface to increase the document surface illuminance.
It is possible to provide an image reading apparatus that has a simple configuration and that can obtain image data with high gradation even with a small light source.

Moreover, since the light source can be smoothly moved along the original glass and the gap between the light source and the original glass does not change rapidly, the original surface illuminance is always kept constant and stable image data is obtained. It is possible to provide the obtained image reading device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged configuration diagram of a first carriage of the image reading apparatus shown in FIG.

FIG. 3 is a state diagram showing a state of a document placing surface of a document glass and a state where a first carriage has moved.

FIG. 4 is a schematic configuration diagram of an image reading apparatus according to a second embodiment of the present invention.

5 is an enlarged configuration diagram of a first carriage of the image reading apparatus shown in FIG.

FIG. 6 is a schematic configuration diagram of an image reading apparatus according to a third embodiment of the present invention.

7 is an enlarged configuration diagram of a first carriage of the image reading apparatus shown in FIG.

FIG. 8 is a schematic configuration diagram of a conventional image reading device.

9 is a schematic enlarged configuration diagram of the first carriage shown in FIG.

[Explanation of symbols]

1 Image reader body 2 Original glass 3 Original cover 4 White reference plate 5a first carriage 5b Rightmost position of the first carriage 5c First carriage 6 light source 7 First reflection mirror 8a Second carriage 8b Rightmost position of second carriage 9 Second reflection mirror 10 Third reflective mirror 11 Imaging lens 12 line image sensor 13 Support members 14 Support roller 15 Support roller 16a Optical path before moving 16b Optical path after moving 17 manuscript aperture 18 Light source unit 19 Guide pin 20 guide holes 21 coil spring 22 Guide roller 23 Light source unit guide surface 24 Guide surface of the first carriage 25a magnet 25b magnet 26a Sliding member 26b Document glass guide surface 27 gap 28 Light source unit 29 Gap adjustment means 31 Gap adjustment plate 33 Vertical hole 35 screws 37 hooks 51 Image reader 55a First carriage 55b Rightmost position of the first carriage 56a Optical path before moving 56b Optical path after movement 58 light source unit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/04-1/207 G03B 27/50 G03G 13/04-13/056 G03G 15/00 107 G03G 15 / 04-15/056 G03G 21/00 365

Claims (9)

(57) [Claims] 1. A document glass on which a document is placed, a light source for illuminating the document, a scanning means for scanning a document reading range of the document glass, and a diffuse reflection light or a transmitted light from the document illuminated by the light source. An image reading apparatus having an optical system for forming light and an image reading means arranged in the main body of the apparatus for reading diffused reflected light or transmitted light from a document imaged by the optical system, wherein the light source is mounted. The scanning means is provided with a light source holding means that holds the light source and the original glass at a constant distance, and holds the light source holding means.
Is a light source holding member for mounting the light source, and the light source holding member.
Light source holding member provided on the member and in contact with the original glass
Scanning of the contact means, the light source holding member and the scanning means
The connecting means for holding the relative position with respect to the direction,
Press to push the source holding member against the original glass
The light source holding means includes a light source holding member.
Pressing distance by pressing means for pressing the document glass against the original glass
If the original glass is deformed and lowered by limiting the separation
In the roller, contact the light source holding member contacting means with the original glass.
Touch the light source, and touch the light source holding member at other locations.
A gap that provides a predetermined gap between the step and the original glass.
Image reading apparatus characterized by including a flop adjusting means. 2. The light source holding member contact means is a guide roller which is provided on the light source holding member and which contacts the original glass and rotates in the scanning direction by the operation of the scanning means. 1. The image reading device described in 1 . 3. The image reading apparatus according to claim 1, wherein the light source holding member contact means is a low friction sliding member provided on the light source holding member. 4. The pressing means for pressing the light source holding member against the original glass comprises a metal or organic elastic member disposed between the light source holding member and the scanning means. The image reading device according to item 1, 2 or 3 . 5. The image reading device according to claim 4, wherein the elastic member is made of a spring, a leaf spring, a sponge, or rubber. 6. The pressing means for pressing and urging the light source holding member against the original glass has magnets arranged so that the same poles face each other at positions facing each other between the light source holding member and the scanning means. according to claim 1, characterized in that the set, or 3 image reading apparatus according. 7. The image reading apparatus according to claim 4, wherein the connecting means comprises a guide pin for supporting the pressing means and a guide hole for guiding the guide pin. 8. The connection means comprises a guide surface of the light source holding means and a guide surface of the scanning means which are superposed on each other in the scanning direction .
Or the image reading device described in item 6 . 9. The predetermined gap is 0.1 mm to 0.1 mm.
Claims 1, characterized in that in the range of 5 mm 8
The image reading device according to any one of 1.