JP2003270732A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately determine a read range of each CCD sensor and easily assemble CCD sensors even in the case that a plurality of CCD sensors are arrayed in the main scanning direction. <P>SOLUTION: A contact glass 1 is divided into a plurality of read areas 3 (3a to 3c) arranged in the main scanning direction (X direction) correspondingly to the number of CCD sensors 2 (2a to 2c) arranged in the main scanning direction, and the read areas 3 are formed by polarizing plates 4 (4a to 4c) out of which adjacent read areas 3 have different polarization directions, and second polarizing plates 7 (7a to 7c) having almost the same polarization directions as polarizing plates 2 are arranged on the incidence face side of the CCD sensors 2. Consequently, read ranges which the CCD sensors 2 should take charge of are accurately determined. A plurality CCD sensors 2 can be easily assembled without maintaining a high assembling precision when being arranged in the main scanning direction. <P>COPYRIGHT: (C)2003,JPO

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 for making an image on a contact glass incident on a CCD sensor line by line in a main scanning direction.

[0002]

2. Description of the Related Art Conventionally, there is an image reading apparatus in which a document placed on a contact glass is irradiated with light so that an image on the document is incident on a CCD sensor line by line in the main scanning direction. In such an image reading apparatus, it is necessary to increase the number of light receiving elements of the CCD sensor in order to increase the resolution in the main scanning direction. However, the number of light receiving elements is limited in order to maintain the accuracy of the arrangement interval of the light receiving elements, and it is difficult to manufacture a line sensor in which a large number of light receiving elements are arranged along the main scanning direction. High cost. Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 6-98098, a configuration in which a plurality of CCD sensors are arranged in the main scanning direction has been proposed.

[0003]

When a plurality of CCD sensors are arranged in the main scanning direction, it is difficult to assemble them while maintaining the arrangement interval between the CCD sensors accurately.
The reading range covered by the CD sensor is also undefined. For this reason, other optical elements such as a light blocking plate and a slit plate that prevent light from interfering with the adjacent CCD sensor are required, and higher assembly accuracy is required.

Therefore, an object of the present invention is to provide an image reading apparatus which can be easily assembled when a plurality of CCD sensors are arranged in the main scanning direction without maintaining high assembly accuracy.

[0005]

The invention according to claim 1 is
Illuminate the original and pass the original image through the contact glass to C
In the image reading device which is incident on the CD sensor, the CC
A plurality of D sensors are arranged in the main scanning direction, the contact glass is divided into a plurality of reading regions arranged in the main scanning direction corresponding to the number of the CCD sensors, and these reading regions are adjacent to each other. In this case, a second polarizing plate having a polarization direction different from that of the polarizing plate in the reading area is disposed on the incident surface side of the CCD sensor.

Therefore, the original image is polarized by the polarizing plates having different polarization directions between the adjacent reading areas, and passes through the second polarizing plate having the same polarization direction as C to pass through the second polarizing plate.
It is incident on the CD sensor.

According to a second aspect of the invention, in the first aspect of the invention, the polarization directions of the second polarizing plates are orthogonal to each other between the second polarizing plates adjacent to each other in the main scanning direction. Has been defined.

Therefore, the reflected light from the original can be clearly separated and made incident on the adjacent CCD sensor. Therefore, the accuracy with respect to the assembly of the adjacent CCD sensors can be further roughened.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing the arrangement of a reading optical system when the contact glass is viewed from below. Below the contact glass 1 on which a document (not shown) is placed, a plurality of CCD sensors 2a, 2b, 2c each having a large number of light receiving elements arranged in the main scanning direction (X direction) are arranged in the main scanning direction. Has been done. The contact glass 1 is divided into a plurality of reading areas 3a, 3b, 3c arranged in the main scanning direction corresponding to the number of CCD sensors 2a, 2b, 2c, and these reading areas 3a, 3b, 3c are polarizing plates 4a, It is formed by 4b and 4c.

Below the contact glass 1, a light source (not shown) for illuminating the original, a mirror 5 for reflecting the reflected light from the original through the contact glass 1, and a reflected light reflected from the mirror 5 are provided. Reading areas 3a, 3b, 3c
Converging lenses 6a, 6b, 6c that converge on the CCD sensors 2a, 2b, 2c are arranged in the main scanning direction. Further, second polarizing plates 7a, 7b, 7c are arranged on the incident surface side of the CCD sensors 2a, 2b, 2. The above polarizing plates 4a, 4b and 4c and the second polarizing plates 7a, 7b and 7c
Are polarized in the same direction when they are opposed to each other in the sub-scanning direction. The polarization directions of the polarization plates 4a, 4b, 4c and the second polarization plates 7a, 7b, 7c are the polarization plates 4a, 4b, 4c adjacent to each other in the main scanning direction, respectively.
The polarization directions of the second polarizing plates 7a, 7b and 7c are orthogonal to each other.

In order to read the original image, the original is read along the upper surface of the contact glass 1 in the sub-scanning direction (Y direction) with respect to the reading optical system 8 including the light source, the mirror 5, the converging lenses 6a, 6b and 6c. ) Moving original method of scanning,
The manuscript on the contact glass 1 is stopped and the reading optical system 8
Although there is a fixed document type in which the scanning is performed in the sub-scanning direction, any method may be used. In the case of a system in which the document is stationary, the document is pressed against the contact glass 1 by the pressure plate 6.

In such a structure, the original on the contact glass 1 is illuminated from below, and the reading optical system contact 8 is relatively scanned with respect to the original in the sub-scanning direction. In this process, reflected light (original image) 10 from the original for each line x1 in the main scanning direction is input to the CCD sensors 2a, 2b and 2c.

More specifically, the reflected light 1 from the document is
0 passes through any one of the polarizing plates 4a, 4b, 4c which become the reading areas 3a, 3b, 3c obtained by dividing the contact glass 1 in the main scanning direction, the reflection direction is bent by the mirror 5, and the converging lenses 6a, 6b, 6c, converges by any of the second polarizing plates 7a, 7b, 7c, and C
It is incident on any of the CD sensors 2a, 2b, 2c.

Therefore, the CCD sensors 2a, 2b, 2
When c are arranged in the main scanning direction, the original image can be read finely by increasing the resolution in the main scanning direction without accurately determining the arrangement interval. In particular, the polarizing plates 7a, 7
The polarization directions of b and 7c are determined so that the polarization directions of the polarizing plates 7a, 7b and 7c adjacent to each other in the main scanning direction are orthogonal to each other.
Even if there is an error in the arrangement interval of b and 2c, the reading range that each CCD sensor 2a, 2b and 2c is responsible for can be accurately determined. Therefore, the adjacent CCD sensors 2
The accuracy for assembling a, 2b, and 2c can be further roughened.

Further, each CCD sensor 2a, 2b, 2c
Since the reading range of the reading area 3a can be accurately determined, a special member for distinguishing the reflected light 10 for each reading area 3a, 3b, 3c is not required, which can contribute to simplification of the structure.

Further, by increasing the number of the CCD sensor 2, the polarizing plate 4, and the second polarizing plate 7 arranged in the main scanning direction, it is possible to easily deal with a wide original, and the structure of the original reading device. Since it is simple, it can be easily manufactured.

[0017]

According to the invention described in claim 1, the contact glass is divided into a plurality of reading areas arranged in the main scanning direction corresponding to the number of CCD sensors, and these reading areas are
The adjacent reading areas are formed by polarizing plates having different polarization directions, and a second polarizing plate having the same polarization direction as the polarization direction of the contact glass having the corresponding polarization direction is disposed on the incident surface side of the CCD sensor. Therefore, the original image is polarized by the polarizing plates having different polarization directions between the adjacent reading areas, and is incident on the CCD sensor through the second polarizing plate having the same polarization direction. As a result, even if the reading area of the original image is divided in the main scanning direction and the reflected light from the original is incident on the plurality of CCD sensors arranged in the main scanning direction, the reading range covered by the CCD sensor can be accurately measured. Can be specified. Therefore, when a plurality of CCD sensors are arranged in the main scanning direction, they can be easily assembled without maintaining high assembly precision.

According to a second aspect of the present invention, in the first aspect of the invention, the polarization directions of the second polarizing plates are such that the polarization directions of the second polarizing plates adjacent to each other in the main scanning direction are orthogonal to each other. Since it is determined, the reflected light from the original can be clearly separated and made incident on the adjacent CCD sensor. Therefore, the accuracy with respect to the assembly of the adjacent CCD sensors can be further roughened.

[Brief description of drawings]

FIG. 1 is a perspective view showing an arrangement of a reading optical system when a contact glass is viewed from below.

[Explanation of symbols]

1 contact glass 2a, 2b, 2c CCD sensor 3a, 3b, 3c reading area 4a, 4b, 4c Polarizing plate 7a, 7b, 7c Second polarizing plate

Claims (2)

[Claims] 1. An image reading apparatus which illuminates an original and makes an image of the original incident on a CCD sensor through a contact glass, wherein a plurality of the CCD sensors are arranged in a main scanning direction, and the contact glass corresponds to the number of the CCD sensors. Correspondingly, the reading area is divided into a plurality of reading areas arranged in the main scanning direction, and these reading areas are formed by polarizing plates having different polarization directions in the adjacent reading areas. An image reading device is characterized in that a second polarizing plate having the same polarization direction as that of the polarizing plate in the corresponding reading area is arranged. 2. The image reading device according to claim 1, wherein the polarization directions of the second polarizing plates are determined so that the polarization directions of the second polarizing plates adjacent to each other in the main scanning direction are orthogonal to each other. .