JPH04234258A - Image reader - Google Patents

Abstract

PURPOSE:To surely detect original size by adhering the reflecting surface of a detecting element on a transparent member. CONSTITUTION:The transparent members 7, 8 fitted in the recessed parts of guide members 5, 6 are confronted with aperture parts 5a, 6a, and the reflecting surface is formed by vapor-depositing a reflecting surface on surfaces 7a, 8a spreading over areas (p), (q) that is the half each transparent member. The surface on one side of an original 100 carried on rollers 1, and 2 is irradiated with a lamp 9 via the aperture part 5a, and image light is introduced to an image-forming lens 19, and is image-formed on the plane of a CCD 21, and the surface on the other side is irradiated with a lamp 10 via the aperture part 6a, and the image light is introduced to a lens 20, and is image-formed on a CCD 22. A read original is sent to the next processing part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device for reading images on both sides of a document.

0002

2. Description of the Related Art In an apparatus that reads a document image using an image sensor such as a CCD, a method is used in which the background portion of the document is made black to detect the edges of the document and the size of the document is detected. In this case, in the case of a semi-transparent document such as tracing paper, the background portion becomes transparent and becomes completely black, making it impossible to read the image of the document. Conventionally, a reflector is provided in the background area, and in areas where there is no original, the original illumination light is reflected in a direction different from that of the image sensor such as a CCD, preventing the light from reaching the image sensor. In the case of a transparent original, one method is to detect the size of the original by diffusing light from the background and reaching an image sensor such as a CCD, making it appear as if the background part of the original is white. It is being

FIGS. 2(a) and 2(b) show an image reading section of an image reading apparatus constructed based on the above concept, in which a document 100 is moved in the direction of arrow B by document conveying rollers 101 and 102. Move the guide member 13
The original 1 is passed through the openings 130a and 131a of 0 and 131.
Both sides of 00 are read and conveyed to the next processing section by conveyance rollers 103 and 104. In FIG. 2A, the guide member 130 is arranged so that an inner surface 130b at one end extending over a range n of the guide member 130, which corresponds to the background of the reading section, and an inner surface 131b at the other end extending over a range m of the guide member 131 become reflective surfaces. 131 is subjected to surface treatment such as nickel plating. In FIG. 2(b), the width of the transparent members 132, 133 shown in FIG. 2(a) is increased, and the guide members 130, 13 are expanded.
130b and 131b corresponding to the background part of 1 are transparent members 13
2', 133'.

0004

[Problems to be Solved by the Invention] However, in the conventional example shown in FIG. 2(a), the background portion is in direct contact with the document and is easily scratched.
), the transparent members 132', 1
Although there is no problem since the transparent members 132', 133' and the guide plates 130, 131 are protected by the transparent members 132', 133' and the guide plates 130, 131, there is no problem. If the reflective surface located in the background part of the image reading is scratched or there is dust such as paper powder, the lamp 10 for illuminating the original is used in that area.
9,110 is scattered, and the light is transmitted to the CCD.
etc., and the light is reflected and C
It is no longer possible to reliably cut the document so that it does not fit into the image sensor of a CD or the like, and the detection of the document size does not function properly. Therefore, Fig. 2(a), Fig. 2(b)
The conventional example shown in Fig. 1 has the disadvantage that such problems tend to occur.

The present invention has been made to solve the above problems, and its object is to provide an image reading device that can reliably detect the size of a document.

[0006]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an image reading device including a detection means for detecting the document size, the detection means comprising:
A reflective surface that reflects the light emitted when reading the original;
A transparent member is provided for protecting the reflective surface from abrasion caused by movement of the document, and the reflective surface has at least an outer periphery in close contact with the transparent member.

[0007]

[Operation] In the image reading device with the above configuration,
Since the reflective surface and the transparent member, which are the components of the detection means, are configured so that at least their outer peripheries are in close contact with each other, dust such as paper powder does not enter between the reflective surface and the transparent member.
This prevents light from being reflected in unintended directions.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1(a) is a schematic diagram of an image reading apparatus according to an embodiment of the present invention, in which reference numerals 1, 2, 3, and 4 are conveyance rollers for conveying a document. The document 100 is conveyed at a constant speed in the direction of arrow A by conveyance rollers 1 and 3 which are driven and rotated and conveyance rollers 2 and 4 which are pressed by the respective conveyance rollers and driven to rotate. 5 and 6 are guide members forming a document conveyance path, and openings 5a and 6 for reading the document image.
A is provided. 7 and 8 are transparent members made of glass or the like fitted into the recesses of the guide members 5 and 6, and the openings 5
Reflective members such as aluminum are vapor-deposited on surfaces 7a and 8a, which are opposite to a and 6a and span approximately half of the regions p and q of the transparent member, to form reflective surfaces. 9 and 10 are lamps for illuminating the manuscript;
Reference numerals 11 and 12 are covers to prevent the light from the lamp from going around to unnecessary areas. 13, 14, 15 and 16,
17, 18 are plane mirrors, 19, 20 are imaging lenses, 2
1 and 22 are image sensors such as CCDs. here,
Transparent members 7, 8, reflective surfaces 7a, 8a, image sensor 2
1 and 22 constitute a detection means G.

One side of the document 100 sent by the transport rollers 1 and 2 is irradiated by the lamp 9 through the opening 5a of the guide member, and the image light is reflected by the plane mirror 13.
, 14, 15 to the imaging lens 19, and the CCD 2
The image is formed on one surface. The other surface is irradiated by the lamp 10 through the opening 6a of the guide member, and the image light is guided to the imaging lens 20 by the plane mirrors 16, 17, and 18, and is imaged on the surface of the CCD 22. Here, the dashed-dotted line indicates irradiation light and image light. And the scanned manuscript 1
00 is transported to the next processing section by transport rollers 3 and 4.

FIG. 1(b) shows the state when there is no document, and the irradiated light from the lamp 9 is reflected in 25 directions by the reflecting surface 8a and does not go toward the CCD image sensor direction 26. Therefore, it is the same as making the reflective surface 8a black. Similarly, the irradiated light from the lamp 10 is reflected in 27 directions by the reflecting surface 7a, and the CCD image sensor direction 28
I will never go to

FIG. 1(c) shows a case where a translucent original such as tracing paper is carried in, and the original illumination light 29 passes through the translucent original 40 and is reflected by the reflective surface 8a.
Illuminates semi-transparent originals from the back. And this light is the original 40
A part of it is scattered in the CCD image sensor direction 26.
The background of the manuscript appears as if it were a blank background. The same applies to the irradiated light 41 from the reflective surface.

[0012] In this way, by directly forming reflective surfaces by vapor deposition of aluminum or the like on the surfaces constituting the reading portions that serve as the background of the front and back sides of the transparent member 40, dust such as paper powder is removed from the reflective members 7a, Since it does not get between the transparent members 8a and the transparent members 7 and 8, misidentification of the original size can be reduced. Of course, if glass or the like is used as the transparent member 40, the transparent members 7 and 8 will protect the reflective surfaces, thereby preventing scratches from occurring during conveyance of the document.

Furthermore, the thickness of the vapor deposited layer can be virtually ignored, and it is sufficient to simply arrange the transparent part corresponding to the reading section and the part forming the reflective surface serving as the background alternately on the front and back sides of the transparent member. The structure is simple and the device can be assembled compactly.

Note that in the above embodiment, the reflective surfaces 7a,
8a is vapor-deposited on the transparent members 7 and 8, but as long as the outer peripheries of the reflective surfaces 7a and 8a are closely attached to the transparent members 7 and 8 by painting, adhesion, etc., the same method as described above can be applied. Effects can be obtained.

[0015]

As explained above, in the image reading device having the above configuration, the reflective surface and the transparent member, which are the constituent elements of the detection means, are configured so that at least the outer peripheries are in close contact with each other, so that the reflection Since dust such as paper powder does not enter between the surface and the transparent member, reflection of light in unintended directions is prevented. This makes it possible to reduce misidentification of document size. Of course, if glass or the like is used as the transparent member, the transparent member protects the reflective surface and prevents scratches from occurring during conveyance of the document.

[Brief explanation of the drawing]

FIG. 1(a) is a schematic configuration diagram of an image reading device according to an embodiment of the present invention, FIG. c) is an explanatory diagram of the operation when a translucent original is carried into the same apparatus.

FIG. 2(a) is a schematic configuration diagram of a conventional image reading device, and FIG. 2(b) is a schematic configuration diagram of another conventional image reading device.

[Explanation of symbols]

G Detection means 7, 8 Transparent member 7a, 8a Reflective surface

Claims (1)

[Claims] 1. An image reading device comprising a detection means for detecting the size of an original, the detection means comprising a reflective surface that reflects light emitted when reading the original; a transparent member to protect from wear associated with
An image reading device comprising: an image reading device, wherein the reflective surface has at least an outer periphery in close contact with the transparent member.