JPH0556231A - Image reader - Google Patents

Abstract

(57) [Abstract] [Purpose] As an image scanner for a facsimile machine, a pair of rod lens arrays are arranged so as to be symmetrical to each other with respect to the center line, so that the apparatus is downsized and the resolution is high. An object of the present invention is to provide an improved image reading device. [Structure] Two rows of rod lens arrays 22 and 23 for forming an image of reflected light from the original 2 are provided toward the reading line of the original, and are arranged at the image forming positions of the rod lens arrays 22 and 23, and the main of the original 2 is arranged. Line-shaped photoelectric conversion elements 24, 25 having the same resolution as the specifications of the reading device 1 in the scanning direction
Is provided corresponding to the rows of the rod lens arrays 22 and 23, the image reading device can be downsized, and the image reading device having excellent portability can be provided.

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 used for an image scanner such as a facsimile machine.

[0002]

2. Description of the Related Art In recent years, facsimile machines have become widespread in general households, and various image reading apparatuses have been proposed.

The image reading device is mounted on an image scanner such as a facsimile device, and the image reading device is downsized in response to downsizing and high resolution of these devices.
There is a strong demand for higher resolution.

The conventional reading device is a reduction optical system using a CCD image sensor as its reading sensor. This reading device is suitable for high resolution of the CCD image sensor, but the device becomes large and small. It was an unsuitable method for becoming a person. Here, in order to realize downsizing, a complete contact image sensor (eg: KICB series made by Kyocera Corporation) or contact image sensor (eg:
An image reading device, which is much smaller than the conventional reduction optical system such as Mitsubishi Electric C series), has come on the market.

A conventional image reading apparatus will be described below with reference to the drawings. As shown in FIGS. 8 and 9, a reading window 3 is provided on the conveying surface of the original 2, and a linear light source 4 for irradiating the reading portion 2a of the original 2 and the reflected light from the original 2 are erected at the same magnification. Rod lens array 5 for imaging
The linear photoelectric conversion element 6 of the contact image sensor, which is an assembly of photoelectric conversion elements 6a having the same resolution as the specifications of the reading device 1 in the main scanning direction, is arranged at the imaging position of the rod lens array 5. It is arranged. Since the line-shaped photoelectric conversion element 6 reads an equal-magnification erect image formed by the rod lens array 5, it has a length equal to or longer than the reading width of the original 2 in the main scanning direction. The line-shaped photoelectric conversion element 6 is mounted on the substrate 6b, and has a feed roller 8 for intermittently moving the main body 7 and the original 2 in the sub-scanning direction at a certain resolution, and is driven by a gear train and a step motor (not shown). is doing.

The operation of the image reading apparatus configured as described above will be described below. The original 2 is intermittently fed in the sub scanning direction by the feed roller 8. At the reading start position, the document 2 is temporarily stopped and one reading line in the main scanning direction is read. Line reading has the following mechanism. First, the reading portion 2 a of the original 2 sent to the reading window 3 is illuminated with the linear light source 4. Then, the information on the document 2 is reflected as light and dark. The reflected light forms an erect image of equal magnification on the surface of the linear photoelectric conversion element 6 by the rod lens array 5.
Since the line-shaped photoelectric conversion element 6 has the same resolution in the main scanning direction as the specifications of the reading device 1, one line is read at a certain resolution. When the reading of one line is completed, the document 2 is sent in the sub-scanning direction by the resolution and stopped, and the reading of the next line is started. Less than,
By repeating this, all the information of the document 2 is read.

[0007]

However, in the above-mentioned conventional structure, the contact image sensor is not suitable for increasing the resolution, and the following problems occur when trying to increase the resolution of the contact image sensor. As shown in FIG. 9, the line-shaped photoelectric conversion element 6 of the contact image sensor is normally divided into the appropriate length D in the main scanning direction as the line length is longer, and the lines are connected in the main scanning direction. ing. From the endmost photoelectric conversion element 6a of the divided line-shaped photoelectric conversion element 6 to the divided end portion, one half of the pitch P of the photoelectric conversion element 6a determined by the main scanning resolution (indicated by P / 2 in the figure). Is. When attempting to increase the resolution, the absolute size of P / 2 becomes very small, so there was a limit to the high resolution in terms of processing technology.

There is also a limit to miniaturization. As described above, since the line-shaped photoelectric conversion element 6 needs to have a length equal to or longer than the width of the original 2 to be read, there is a problem that it cannot be made smaller than the reading width of the original 2. is doing.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an image reading apparatus which is downsized and has a high resolution.

[0010]

In order to achieve the above object, the image reading apparatus of the present invention combines reflected light from an original document in order to solve the drawbacks of high resolution and miniaturization. At least two rows of imaged rod lens arrays are provided toward the same reading line of the original,
The linear photoelectric conversion elements, which are arranged so as to be symmetrical to each other with respect to the center line and have the same resolution as the specifications of the reading device in the main scanning direction of the original, are formed at the imaging position of the rod lens array. Are arranged and are provided corresponding to the rows of the rod lens array.

[0011]

With this configuration, it is possible to separately provide a high resolution and further downsizing of the image reading apparatus which has been conventionally demanded, and it is possible to provide an image reading apparatus excellent in high image quality and portability.

[0012]

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same parts as those in the conventional example are designated by the same reference numerals. The point different from the conventional one is that two rod lens arrays for imaging reflected light from the original are provided toward the same reading line of the original, arranged at the image forming position of the rod lens array, and a reading device in the main scanning direction of the original. The point is that line-shaped photoelectric conversion elements having the same resolution as the specifications of are provided corresponding to the columns of the rod lens array.

As shown in FIGS. 1 (a), 1 (b) and 1 (c), a reading window 3 is provided on the conveying surface of a document 2 having a width L, and the linear light sources 20 and 21 serve as a reading section 2a for the document 2.
2 arranged so as to irradiate the laser beam, divided into two in the main scanning direction and slid in the main scanning direction.
6 and the main body 7 so as not to overlap each other in the sectional direction. Rod lens arrays 22 and 23 for erecting the reflected light from the original 2 at an equal magnification are provided, and are mounted on the arm 26 and the main body 7, respectively.
They are arranged so as not to block the optical paths of 0 and 21 toward the reading line 2a of the original 2 and in different directions with respect to the original 2. Since the rod lens arrays 22 and 23 are constructed by forming a composite image by a plurality of rod lenses, it is necessary to wrap them in the main scanning direction.
The line-shaped photoelectric conversion elements 24 and 25 are arranged at the imaging positions of the rod lens arrays 22 and 23, respectively, and an assembly of photoelectric conversion elements 6a having the same resolution (pitch P1) as the specifications of the reading device 1 in the main scanning direction. And are mounted on the substrates 27 and 28, respectively, and are mounted on the arm 26 and the main body 7 (the linear photoelectric conversion element 24 mounted on the arm 26 is the main photoelectric conversion element 25 for the photoelectric conversion element 25 mounted on the main body 7). In order to absorb the mechanical variation in the scanning direction, the overlapped portion may be subjected to image processing by an image processing unit (not shown) by overlapping in the main scanning direction). The feed roller 8 for intermittently moving the document 2 in the sub-scanning direction at a certain resolution is driven by a gear train (not shown) and a step motor.

The operation of the image reading apparatus configured as described above will be described with reference to FIGS. First, the document 2 is intermittently fed in the sub-scanning direction by the feed roller 8. At the reading start position, the document 2 is temporarily stopped and one reading line in the main scanning direction is read. Line reading has the following mechanism. First, the reading section 2a of the original 2 sent to the reading window 3 is illuminated with the linear light sources 20 and 21. Then, the information on the document 2 is reflected as light and dark. The reflected light forms an equal-magnification erect image on the surfaces of the linear photoelectric conversion elements 24 and 25 by the rod lens arrays 22 and 23. The line-shaped photoelectric exchange elements 24 and 25 have a pitch P1 in the main scanning direction.
Since it has a resolution of, one line is read at this resolution. When the reading of one line is completed, the document 2 is sent in the sub-scanning direction by the resolution and is stopped, and the reading of the next line is started. Hereinafter, by repeating this, all the information of the original 2 is read.

In the case of non-reading, as shown in FIGS. 3 and 4, the arm 26 having the linear light source 20, the rod lens array 22, and the linear photoelectric conversion element 24 mounted thereon is slid, and the arm 26 is housed in the main body 7. Size of original 2
Can be smaller than the width of.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS.

As shown in FIGS. 5A and 5B, a reading window 3 is provided on the conveying surface of the original 2 having a width L, and the linear light source 30 is arranged so as to illuminate the reading portion 2a of the original 2. Has been done. The rod lens arrays 31 and 32 are for erecting the reflected light from the original 2 at an equal magnification, and are directed toward the reading line 2a of the original 2 so as not to block the optical path of the linear light source 30, and the original. 2 are arranged in different directions. The linear photoelectric conversion elements 34 are arranged at the image forming positions of the rod lens arrays 31 and 32, respectively.
A set of photoelectric conversion elements 6a having the same resolution (pitch P2) as the specifications of the reading device 1 in the main scanning direction,
The photoelectric conversion elements 6a are mounted on the same substrate 35 in a zigzag manner by dividing the photoelectric conversion elements 6a into an appropriate length D1 in the main scanning direction. However, it may be mounted on another substrate). The feed roller 8 is for intermittently moving the document 2 in the sub-scanning direction at a certain resolution, and is driven by a gear train (not shown) and a step motor.

The operation of the image reading apparatus configured as described above will be described with reference to FIG. The original 2 is intermittently fed in the sub scanning direction by the feed roller 8.
When the reading start position is reached, the original 2 temporarily stops,
One reading line in the main scanning direction is read. Line reading has the following mechanism. First, the reading portion 2 a of the original 2 sent to the reading window 3 is illuminated with the linear light source 30. Then, the information on the document 2 is reflected as light and dark. The reflected light is imaged by the rod lens arrays 31 and 32 on the surface of the linear photoelectric conversion elements 34 arranged in a zigzag pattern as shown in FIG.
Since the line-shaped photoelectric conversion element 34 has a resolution of the pitch P2 in the main scanning direction, one line is read at this resolution. When the reading of one line is completed, the document 2 is sent by the resolution in the sub-scanning direction and stopped, and the reading of the next line is started. Hereinafter, by repeating this, all the information of the original 2 is read.

With the structure of this embodiment, the line-shaped photoelectric conversion element 34 divided by the length D1 as shown in FIG.
P3 from the photoelectric conversion element 6a at the end to the division end
Can be made longer than half of the pitch of the photoelectric conversion elements 6a as in the conventional case, so that high resolution can be achieved.

Further, as shown in FIG. 7, the photoelectric conversion element 6a
Are arranged in a staggered pattern for each minimum pitch P4, the dimension P5 from the photoelectric conversion element 6a at the division end to the division end can be made the same as the photoelectric conversion element 6a at the minimum pitch P4. Is obtained.

[0021]

As described above, according to the present invention, it is possible to separately increase the resolution of an image reading apparatus, which has been widely demanded, and further reduce the size, and it is possible to realize an image reading apparatus excellent in high image quality and portability. Can be realized.

[Brief description of drawings]

1A is a plan view of an image reading apparatus according to a first embodiment of the present invention, FIG. 1B is a sectional view taken along line AA of the apparatus, and FIG. 1C is a sectional view taken along line BB of the apparatus.

FIG. 2 is a perspective view of the same.

FIG. 3A is a plan view of the same device when not being read, and FIG. 3B is a sectional view taken along line CC of the same device.

FIG. 4 is a perspective view of the same.

FIG. 5A is a plan view of an image reading apparatus according to a second embodiment of the present invention, and FIG. 5B is a sectional view taken along line DD of the apparatus.

FIG. 6 is a plan view of the same line photoelectric conversion element.

FIG. 7 is a plan view of another example of a line photoelectric conversion element in the same embodiment.

FIG. 8 is a sectional view of a conventional image reading device.

FIG. 9 is a plan view of a conventional linear photoelectric conversion element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reading device 2 Original 3 Reading window 8 Feed roller 20, 21, 30 Line light source 22, 23, 31, 32 Rod lens array 24, 25, 34 Line photoelectric conversion element

Claims (2)

[Claims] 1. A document is conveyed in the sub-scanning direction, and
A light source for irradiating a document is provided, and at least two or more rows of rod lens arrays for imaging reflected light from the document are provided toward the reading line in the main scanning direction of the document, and the image formed by the rod lens array is read. An image reading apparatus, which is arranged at an image forming position and has a reading sensor row having a certain resolution in the main scanning direction of the document corresponding to the row of the rod lens array. 2. A reading line in the main scanning direction of a document is
2. The image reading device according to claim 1, wherein at least two rows corresponding to the rows of the rod lens array are arranged so that the reading sensor rows are divided and read in the main scanning direction.