JPH04213959A - Image reader - Google Patents

Abstract

PURPOSE:To form the optical path of an optical system for introducing the light reflected from a document toward image sensors perpendicular to the document plane and to form the images for one line of the document as 1:1 erecting real images by arraying plural pieces of the image sensors in 3 directions without using half mirrors. CONSTITUTION:The optical system which introduces the reflected light for one line of the document in the direction perpendicular to the document plane is disposed to face the moving route of the document. The plural image sensors are arrayed in the 2 directions in such a manner that the effective widths for reading are optically connected. Mirrors 22, 27, 28, 35 which have approximately the same widths as the effective widths for reading of the image sensors 25, 31, 32, 36 are provided to face the image sensors 25, 31, 32, 36 of at least the one direction. A part of the images for one line of the document are made incident on the image sensors 25, 31, 32, 36 on one direction side facing these mirrors by the mirrors and the other part of the images for the above-mentioned one line are formed as the 1:1 erecting real images on the image sensors 20, 21, 30, 33, 34 arranged on the extension of the optical path of the above- mentioned optical system 18 without intervening the half mirrors.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact sensor type image reading device.

0002

[Prior Art] Japanese Patent Publication No. 1-13787 describes the fifth
A half-mirror type image reading device shown in FIG. 6 and FIG. 6 is disclosed.

The image reading device shown in FIG. 5 has a plurality of image sensors 1 and 2 arranged in two directions so that their effective reading widths are optically connected, and the image sensor 2 in one direction is affected by the reflection action of a half mirror 3. A part of the image of one line of the original 4 is incident on the image sensor 1 in the other direction.
The light transmission effect of the half mirror 3 allows light to enter the other part of the image of one line of the original 4. In the figure, 5, 6
is a light source, and 7 is an optical system.

In the image reading device shown in FIG. 6, among the image sensors 1a, 1b and the image sensor 2 arranged in two directions, the image sensors 1a, 1b arranged in one direction receive an image of the document directly from an optical system. The image from the optical system is transmitted to the image sensor 2 arranged in the other direction by the mirror 8.
Several pixels of the mirror 8 near the joints of the image sensors 1a, 1b, 2 serve as half mirrors 9, 10.

The image reading device shown in FIG. 7 disclosed in Japanese Patent Publication No. 59-42511 has a pair of optical systems 11 and 12 arranged in an inverted V-shape below the original 4 and directed toward the reading line on the 4th side of the original. A plurality of IC image sensor chips 1 and 2 are arranged in a staggered manner so as to cover the width of the original without any gaps.
, 2, the reflected light from the reading line of the original is imaged as a substantially one-to-one erect real image. Note that 13 and 14 are light sources.

[0006]

[Problems to be Solved by the Invention] In the half mirror system shown in FIG. The limit is about 43% to 43%, and not 50% to 50%. For this reason, it is difficult to secure a sufficient amount of light, forcing the use of fluorescent lamps.

[0007] The use of fluorescent lamps increases the size of the apparatus, which has the drawback of leading to a reduction in resolution. The partial half-mirror system shown in FIG. 6 solves the defects of the half-mirror system described above. However, the light incident state of each image sensor is divided into three states: direct incidence, transmitted incidence through a half mirror, and reflected incidence through a high reflection mirror.

When three image sensors are considered as one image sensor, there are differences in performance at the chip level or module level of each image sensor, and differences in reading conditions due to differences in the amount of light. However, there is a drawback that image uniformity cannot be ensured.

The V-shaped method shown in FIG. 7 has a drawback in that the optical path of the optical system is tilted with respect to the original, resulting in reading the original from an oblique angle, resulting in a reading error. The present invention aims to eliminate the above-mentioned defects.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention provides light sources 17 and 18, and optical paths facing substantially perpendicularly to the original onto which the light from the light sources 17 and 18 is irradiated. an optical system 18 that guides the reflected light over the entire area for one line onto a substantially vertical axis; and an optical system 18 that is disposed opposite to each other on an extension of the optical path of the optical system 18 and guides a portion of the reflected light in a predetermined direction. mirrors 22, 27, 28, 35 having a width corresponding to a portion of the width of the mirrors 22, 27, 2;
Image sensor 25 arranged in the reflection direction of 8, 35,
31, 32, 36, and image sensors 20, 21, 30, 33, 34 arranged on an extension of the optical path of the optical system 18 so as to receive other parts of the reflected light,
The reflected light for one line of the document is divided and formed on the plurality of image sensors as a substantially one-to-one erect real image.

[0011]

[Operation] In the above configuration, the image on the reading line of the original is guided by the optical system 18 and the mirrors 22, 27, 28, and 35 and arranged in one direction as a substantially 1:1 erect real image. Images are formed on image sensors 25, 31, 32, and 36. On the other hand, the image from the optical system 18 is formed as a one-to-one erect real image on the image sensors 20, 21, 30, 33, and 34 arranged on the extension line of the optical path of the optical system 18.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail below with reference to embodiments shown in the accompanying drawings. In FIG. 2, a paper guide 13 is supported by the body of the image reading device, and is made of a transparent glass plate.

A paper conveyance roller 14 connected to a drive system is disposed on the upper surface side of the paper guide 13.
The document 15 is configured to be conveyed in the arrow direction on the paper guide 13 by the rotation of the paper guide 13 .

Light sources 17, 17 consisting of light emitting diodes are supported by the body so as to face the reading line 16 on the paper guide 13.

An optical system 18 consisting of a focusing rod lens array (trade name Selfoc Lens, manufactured by Nippon Sheet Glass) is disposed below the reading line 16 over the entire length of the reading width on the paper guide 13. supported by the aircraft.

The optical system 18 is configured to guide approximately one line of image on the reading line 16 of the original 15 in a downward direction perpendicular to the supporting surface of the paper guide 13, that is, the original 15.
The direction of the optical path is set perpendicular to the surface of the paper guide 13.

Below the optical system 18, there is provided a width that is inclined at approximately 45 degrees with respect to a vertical axis perpendicular to the surface of the paper guide 13, and has a width that is equal to or slightly longer than the entire length of the reading line 16. A transparent glass plate 19 is provided.

Image sensors 20 and 21 are arranged directly below a predetermined range on both sides of the transparent glass plate 19.

A high-reflection mirror 22 is formed by vapor deposition on the central surface of the transparent glass plate 19 facing the optical system 18.

Transparent portion 23 on one side of the transparent glass 19
The image of one third of the reading line 16 passes through the transparent part 24 on the other side, and the image of one third of the reading line 16 passes through the transparent part 24 on the other side.
The widths of each of the transparent parts 23 and 24 and the mirror 22 are set so that the image of the remaining one-third of the reading line 16 is guided to the mirror 22. .

An image sensor 25 is arranged parallel to the horizontal reflection direction of the mirror 22.

The image sensors 20, 21, 25 are:
The length of each reading section, that is, the effective reading width is set to one third of the length of the reading line 16 so that the entire area of the image on the reading line 16 can be read as one line.

Regarding the mirror 22, if the effective reading width of the image sensor 25 is l and the width of the mirror 22 is L, it is preferable that L=l plus or minus 1/2 pixel width or less. That is, the error range of the width of the mirror 22 is 2 pixels.
It is set to less than one-fold.

The distance between the reading line 16 and each image sensor 20, 21, 25 is set at a constant interval.

In the above configuration, when the original 15 moves on the paper guide 13 in the arrow direction, an image of the original 15 along the reading line 16 set on the paper guide 13 enters the optical system 18. Via the transparent parts 23 and 24 and the mirror 22, the image is formed in a line on the image sensors 20, 21, and 25 as a substantially one-to-one real image.

In this embodiment, one line of image along the reading line 16 is divided into three parts, and each image is formed into one line on the corresponding image sensors 20, 25, and 21.

In the above embodiment, one-third of the central part of the image for one line is guided to the mirror 22, and the remaining parts on both sides are guided to the transparent parts 23 and 24. 3
As shown in the figure, one-third of each side of the image for one line is guided to mirrors 27 and 28 provided on a transparent glass plate 26 by vapor deposition, and the central part of the image for one line is The remaining one-third part is guided to the transparent part 29, the image sensor 30 is arranged directly under the transparent part 29, and the mirror 27
, 28 may be provided with image sensors 31 and 32 facing each other.

Furthermore, as shown in FIG. 4, the transparent parts 23, 24, 29 in the above embodiment are not glass plates 19, 26, but are simply space parts, and the light image from the optical system passes through these space parts. It may be configured so that the light directly enters the image sensors 33 and 34 through the light. In this example, mirror 3
5 is disposed only in an area that reflects an optical path of a predetermined width, and the mirror 35 guides an image of a predetermined divided width on the reading line 16 to the opposing image sensor 36.

[0029]

[Effects] As described above, the present invention does not use a half mirror, so there is little reduction in the amount of light. Furthermore, since the image sensor is optically connected using a mirror, the image on the reading line of the document sheet can be read with a uniform amount of light. Furthermore, since the optical path of the optical system can be set perpendicular to the document paper, there are advantages such as fewer reading errors compared to a case where a pair of optical systems are arranged in a V-shape.

[Brief explanation of the drawing]

FIG. 1 is an explanatory external view showing the configuration of an image reading device.

FIG. 2 is an explanatory side view showing the configuration of an image reading device.

FIG. 3 is an explanatory external view showing another embodiment.

FIG. 4 is an explanatory external view showing another embodiment.

FIG. 5 is an explanatory diagram of the prior art.

FIG. 6 is an explanatory diagram of the prior art.

FIG. 7 is an explanatory diagram of the prior art.

[Explanation of symbols]

1 Image sensor 2 Image sensor 3 Half mirror 4 Manuscript 5 Light source 6. Light source 7. Optical system 8 Mirror 9 Half mirror 10 Half mirror 11 Optical system 12 Optical system 13 Paper guide 14 Paper leaf conveyance roller 15 Manuscript 16 Reading line 17 Light source 18 Optical system 19 Transparent glass plate 20 Image sensor 21 Image sensor 22 Mirror 23 Transparent part 24 Transparent part 25 Image sensor 26 Transparent glass plate 27 Mirror 28 Mirror 29 Transparent part 30 Image sensor 31 Image sensor 32 Image sensor 33 Image sensor 34 Image sensor 35 Mirror 36 Image sensor

Claims (1)

[Claims] Claim 1: Light sources 17, 18 and the light sources 17, 1
an optical system 18 whose optical path faces substantially perpendicularly to the original onto which the light from 8 is irradiated, and which guides the reflected light over the entire area of at least one line of the original onto a substantially vertical axis; mirrors 22, 27, 28, and 35 arranged oppositely on an extension line and having a width corresponding to the width of a portion of the reflected light that guides a portion of the reflected light in one predetermined direction;
image sensors 25, 31, 32, and 36 arranged in the direction of reflection of the lights 27, 28, and 35; and an image sensor arranged on an extension of the optical path of the optical system 18 to receive other parts of the reflected light. 20, 21, 30, 33, and 34, and the reflected light for one line of the document is divided and imaged on the plurality of image sensors as a substantially one-to-one erect real image. Characteristic image reading device.