JPS6225554A - Picture reader - Google Patents

Abstract

PURPOSE:To always attain correct reading independently of deformation of an original by providing an original guide in the vicinity of a roller in contact with the original in reading a picture on the original. CONSTITUTION:The original guide 20 regulating the position of an original is provided between rollers 16a and 16b so that the original face is not placed upward from the focus of a rod lens 13, that is, so that the original face is not placed in a direction of the lens 13 from the focus of the lens 13. As the original guide 20, a light-transmittable material such as an acrylic plate is preferred and a light transmission window 19 of a long hole shape is formed on a position opposite to the lower part of the lens 13. As a result, even when the original is depressed by the rollers and then deformed, since it is prevented that the original face is defocused between the lens, reading without causing out-of-focus is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image reading device that reads an image on a document by manual sub-scanning, and particularly to an image reading device that can perform good reading without blur.

[Technical background of the invention and its problems]

Transmit the image on the original by facsimile, or
g! 2. Description of the Related Art Devices that read images on a document by being manually moved over the document for input into a processing device are known as handy scanners, hand scanners, and the like. This uses a line image sensor configured by arranging a plurality of photoelectric conversion elements in one direction, and the scanning of reading the image on the original in the arrangement direction, that is, the main scanning, is replaced by the movement of the image sensor relative to the original, that is, the sub-scanning. The image on the document is read by periodically repeating scanning. An image on a document is formed on an image sensor by an optical lens such as a Rondo lens. Unlike facsimile machines and the like that are currently in practical use, such image reading devices can easily read images on documents other than sheet-like documents, such as books, and It is also possible to selectively read only desired areas.

By the way, in this type of image reading device, for example, as described in Japanese Patent Application Laid-Open No. 59-63873,
Some devices use rollers to restrict the moving direction of the device to a direction perpendicular to the arrangement direction of the photoelectric conversion elements in the line image sensor, and to enable the device to move smoothly over the document. However, when an image reading device is pressed against a document, the document is deformed by being pressed by the row, which shortens the distance between the document surface and the optical lens, resulting in a problem in that the read image deteriorates. That is, since optical lenses such as the above-mentioned Rondo lens generally have an extremely shallow depth of focus, when the distance between the document surface and the lens becomes short,
As a result of the position of the document surface being outside the depth of focus, the image formed on the image sensor becomes blurred, making it impossible to read the document correctly.

[Purpose of the invention]

The present invention has been made in order to solve such conventional problems, and when reading an image on a document by manually moving it over the document, it is possible to always read the image correctly regardless of the deformation of the document due to pressure. The purpose of the present invention is to provide an image reading device capable of reading images.

[Summary of the invention]

In order to achieve this object, the present invention provides a document guide in the opening of the case of an image reading device in close proximity to a roller that comes into contact with the document when reading an image on the document. It is characterized in that the position of the document is regulated so that it does not deviate from within the depth of focus of the optical lens for forming an image on the line image sensor in the direction of the lens.

This document guide is preferably made of a translucent material so that a sufficient amount of light from the light source reaches the document, and a sufficient amount of light reflected from the document surface enters the optical lens. As such, a shape having a light transmission window at a position facing the optical lens is desirable.

〔Effect of the invention〕

According to the present invention, by providing the above-mentioned document guide, even if the document is pressed and deformed by the roller, the document surface is prevented from moving out of the depth of focus of the lens toward the lens. This enables good image reading without any blemishes.

[Embodiments of the invention]

Hereinafter, an embodiment will be described in which the present invention is applied to a facsimile machine in which an image reading device and a transmitting device are separable, and sub-scanning can be performed both manually and automatically. In Figures 1<a and (b), the image reading/taking device 1 and the transmitting device 2 are separated, and the image reading device 1 is manually moved over the document A (book) to perform reading by manual sub-scanning. FIG. 2 is a perspective view and a cross-sectional view showing aspects of the
) are a perspective view and a sectional view illustrating a case where an image reading device 1 and a transmitting device 2 are placed one on top of the other, and a sheet-like original B is automatically transferred between the two and read by automatic sub-scanning.

As shown in the figure, on the image reading device 1 there is a power button,
An operation section 3 such as a reading button and a display section 4 are provided. The image reading device 1 and the transmitting device 2 are coupled by a multicore cord 5, and the image signal obtained by reading the image with the image reading device 1 is modulated in the transmitting device 2 and then supplied to the acoustic coupler 6. . The acoustic coupler 6 is set in a telephone (not shown) and converts the modulated knee signal from the transmitting device 2 into an acoustic signal. The image reading device 1 has a first case 11 with an open bottom, and a line image sensor 12 is installed above the case 11. A rod lens 13 called a Selfoc lens (trade name) is installed in front (below) of the image sensor 12.
is located. The line image sensor 12 is constructed by arranging photoelectric conversion elements made of COD or amorphous silicon in a line, for example.
This is called a contact type image sensor having a length equal to the width of a standard size document such as No. 4. rod lens 13
transmits the image on the document to this image sensor 12.
This constitutes a so-called equal-magnification imaging system that forms images with a size of 1:1. In addition, a light source for illuminating the document surface (for example, fluorescent 14 lights are provided.

And line image sensor 12. Rotsudre. The shafts 15a and 15b are provided parallel to the lens 13 and the light source 14 and at a predetermined distance from each other so as to slightly protrude from the opening of the case 11, in other words, to protrude slightly from the rod lens 13 toward the document side. As such, the roller 16a is preferably substantially rigid, for example made of hard plastic or lightweight metal.

16b is supported. The rollers 16a and 16b are connected by a rotation transmission mechanism 17a such as a belt. Further, a rotary encoder 18 for detecting the relative movement speed of the image sensor 12 with respect to the original is attached to another shaft 15c provided above in the first case 11 in parallel with the shafts 15a and 15b. There is. This rotary encoder 18 is a rotation transmitter 117b such as a belt.
via a roller 16t).

And, between the rollers 16a and 16b, so that the document surface is not located above the depth of focus of the rod lens 13,
That is, a document guide 20 is provided for regulating the position of the document so that the document surface does not deviate from the depth of focus of the lens 13 toward the lens 13 . This document guide 20 is preferably made of a translucent material such as an acrylic plate, and the lens 1
A long hole-shaped light transmitting window 19 is formed at a position facing the lower part of the window 3 .

On the other hand, as shown in FIG. 2(b), the transmitting device 2 has a second case 21 that is separate from the first case 11 of the image reading device 1 and has an open upper side. Inside this second case 21, there is a shaft 1 in the second case 11.
Shafts 22a and 22b are provided at positions facing 5a and 15b, and rollers 23a and 23 are attached to these shafts 22a and 22b.
b is supported. Note that in this example, the roller 23a.

There are a plurality of each 23b, and the shafts 22a, 2 are connected at predetermined intervals.
It is attached to 2b. Further, a motor 24 as a drive source for automatic document feeding is arranged inside the second case 21. The rotation of this motor 24 is caused by the gear 25a
~25d. Note that the gear 25d provided coaxially with the roller 23a also meshes with the gear 25e provided coaxially with the roller 16a of the image reading device 1 in the state shown in FIG.

Furthermore, a document guide 26 is provided in the opening of the second case 21 to prevent the surface of the document B from being located below the depth of focus of the rod lens 13.

Note that it is desirable that one end of the document guide 26 on the side in the insertion direction of the document B is bent downward as shown in the figure or formed into a taper so as not to interfere with insertion of the original IB.

In the above configuration, when reading an image on an original mA such as a book by manual sub-scanning, the image reading device 1 is separated from the transmitting device 2 as shown in FIG.
manually move it in the direction of the arrow above the page of document A that you want to read. This causes the image on that page to be displayed on the rod lens 13.
The image signal is read by the line image sensor 12 via the line image sensor 12, and an image signal is output from the image sensor 12. This image signal is sent to the transmitting device 2 via the code 5, modulated, and then sent out to the telephone line via the acoustic coupler 6.

Rotary encoder 1 provided in image reading device 1
8 generates one pulse signal every time the roller 16b rotates a certain maximum. That is, the rotary encoder 18 detects the relative movement speed of the image sensor 12 with respect to the document A via the roller 16b and the rotation transmission mechanism 17b, generates a pulse signal with a frequency corresponding to the detected speed, and thereby controls the image sensor 12. Controls the start timing of main scanning.

Here, when the document reading device 1 is moved over the document A,
The document A is pressed and deformed by the rollers 16a and 16b, and tends to be displaced in the direction of the lens 13. Especially when the original @A is a book, the roller 16a.

This situation is likely to occur because it has elasticity against the pressure of 16b. However, according to the present invention, the roller 16a
, 16b is provided, and this document guide 20 prevents the surface of the original IA from moving out of the depth of focus of the lens 13 and toward the lens 13. Therefore, there is no blur caused by the surface of the document A being outside the depth of focus of the lens 13, and good image reading is possible.

Furthermore, if the document guide 2o is made of a translucent material, the light from the light source 14 will sufficiently reach the document A, and the reflected light from the document A will be incident on the lens 13 without being hindered. Furthermore, if a light transmission window 19 made of a long hole parallel to the photoelectric conversion element array direction of the image sensor 12 is formed at the bottom of the lens 13 of the document guide 20, the loss of the amount of light reflected from the document A can be eliminated. , line image sensor 12
It is possible to improve the S/N ratio of the image signal output from the.

Note that the document guide 20 may be formed with both sides separated with the light transmission window 19 in between, but as shown in FIG. It is more desirable. In this way, the document guide 20
Since both ends of the light-transmitting window 19 come into contact with the original A, the edges of the original A will not be caught by the ends of the light-transmitting window 19 when the image reading device 1 is moved over the original MA. , it becomes possible to move the image reading device 1 smoothly.

FIG. 4 shows another example of the configuration of the document guide 20, in which the end 19a opposite to the direction of relative movement of the light transmitting window 19 with respect to the document A (indicated by an arrow) is folded upward, that is, toward the lens 13. It's bent. In this way, when the image reading device 1 is moved in the direction indicated by the arrow, even if the end of the original IA hits the end 19a of the light transmission window 19, the end 19a of the original IA
By being guided by the surface of the document guide 20 at point a, the image reading device 1 can be moved smoothly in the same manner as in the case of FIG. 3 because it does not get caught by the end portion 19a. Further, even if the width of the document is smaller than the length of the light transmission window 19, this effect is the same. Note that it is also possible to combine the configuration in FIG. 4 and the configuration in FIG. 3.

Next, when reading the image on the sheet document B by automatic sub-scanning, as shown in FIG. Second
superimposed on the case 21 of. In this state, the rollers 16a and 16b on the image reading device 1 side and the roller 23a on the transmitting device 2 side.

23b, the document B is inserted from above the protrusion 21a of the second case 21, and the motor 24 is energized and driven by pressing the read button. The rotation of the motor 24 is caused by the gear 2
The rotation is transmitted to the roller 16a at a predetermined reduction ratio via the rotation transmission mechanism 17a from the roller 16a through the rotation transmission mechanism 17a. As a result, the document B is transferred to rollers 16a, 16b and roller 23a.

23b, the image is transferred in the direction of the arrow, and the image is read in the same manner as described above.

Note that the present invention is not limited to the above embodiments,
For example, in the embodiment, the case where the present invention is applied to a facsimile machine has been described, but the present invention can also be applied to an image reading device for inputting a read image to an image processing device using a computer or the like. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[Brief explanation of drawings]

1(a) and 1(b) are a perspective view and a cross-sectional view illustrating a mode in which an image reading device according to an embodiment of the present invention is used to read an image by manual sub-scanning of a facsimile machine, and FIG. Figures (a) and (b) are perspective views and cross-sectional views showing modes of image reading by automatic sub-scanning of the facsimile machine, and Figures 3 and 4 are configurations of the document guide in the image reading apparatus of the present invention. It is a perspective view and a sectional view showing an example. 1... Image reading device, 2... Transmitting device, 3...
Operation unit, 4...Display unit, 5...Multi-core cord, 6...
・Acoustic coupler, 11...first case, 12...
Line image sensor, 13... Rod lens, 14
...Light source, 16a, 16b-o-ra, 17a, 17b
...Rotation transmission mechanism, 18...Rotary encoder,
19...Light transmission window, 20... Original guide, 21...
・Second case, 23a, 23b・O-ra, 24...
- Motor, 25a to 25e...Gear, 26...Document guide. Applicant's agent Patent attorney Takehiko Suzue (b) Figure 1 Figure 2 Figure 3 Figure 4

Claims (5)

[Claims] (1) An image reading device that reads images on a document by manually moving it over the document includes a case with an open bottom and a plurality of photoelectric conversion elements fixed in the case and arranged in one direction. a line image sensor, a lens for forming an image on a document on the line image sensor, a shaft attached to the case parallel to the arrangement direction of the photoelectric conversion elements in the line image sensor, and a shaft on the axis. a roller that is attached to protrude from the lens toward the document side and comes into contact with the document when reading an image on the document; and a roller that is installed in the opening of the case in close proximity to this roller so that the document surface is at the focal depth of the optical lens. An image reading device comprising: a document guide for regulating the position of the document so that the document does not come off from inside toward the lens. (2) The image reading device according to claim 1, wherein the document guide is made of a translucent material. (3) The image reading device according to claim 1 or 2, wherein the document guide has a light transmission window at a position facing the optical lens. (4) The image reading device according to claim 3, wherein the light transmission window is a long hole formed in a direction parallel to the arrangement direction of the photoelectric conversion elements and closed at both ends. (5) The image according to claim 3 or 4, wherein the light transmitting window has an end portion facing the direction of relative movement with respect to the original document that is bent toward the optical lens side. reader.