JPH10136168A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a defective image with black stripes by preventing deposition of a foreign material onto a read effective range of an original contact member in the case of reading an image while a face of an original is directed upward. SOLUTION: An original contactor member 20 made of a metal or a resin or the like is formed entirely to be opaque. An opening slit 21 is made to the middle of the member 20. The size of the opening 21 is selected larger than the size of an effective image area 22 at image reading, resulting that a plane of the original contact member 20 covering the effective image area range 22 is cut off. Thus, a foreign material is no longer depositted onto the effective image area range 22 of the original contact member 20, occurrence of a defective image due to the foreign material is prevented.

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 reading an image with a document image facing upward, such as a document reading apparatus for reading a book document, such as a copying machine, a scanner, and a facsimile.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 02-035568 and Japanese Utility Model Application Laid-Open No.
Although there is one disclosed in Japanese Patent Publication No. 139063, the configuration of a book document reading apparatus having a page turning mechanism as shown in FIG. 1 will be described.

A main body 1 shown in FIG. 1 includes a pair of document tables 3a and 3b on which a book document 2 such as a book is placed in an open state, and a carriage 4 for reading the book document 2. The carriage 4 includes an optical system 6 for reading a document in a case 5 and a turning belt 7 for turning pages of the book document 2, and the carriage 4 is reciprocated by a drive system (not shown). . The optical system in the case 5 includes a photoelectric device 8 such as a CCD, a condenser lens 9, a first to a third
Mirrors 10 to 12 and light sources 13 and 14 are provided. In the figure, reference numeral 15 denotes a contact glass disposed below the carriage 4 so as to contact the originals on the original tables 3a and 3b. In the drawings, 16a and 16b are pressing rollers, and 17a and 17b are pressing sheets.

When reading the book original 2 with this apparatus,
Light emitted from the light sources 13 and 14 and reflected on the original surface is reflected by the first mirror 10, the second mirror 12 and the third mirror 12 through the contact glass 15,
The reflected light that is incident upon and is read is collected and
, Where it is converted to an electrical signal.

[0005]

The contact glass 15 of the conventional image reading apparatus as described above, that is, the original contact member, is a transparent member having a flat plate shape as shown in FIG. The reflected light from the original for reading the image is transmitted through the transparent flat contact glass 15. Therefore, when foreign matter (dust) adheres to the reading effective range on the contact glass 15 surface,
There has been a problem that both the light from the light sources 13 and 14 and the reflected light from the document are interrupted in the optical path, and the image at that portion is lost, resulting in a black streaked read image.

In the apparatus shown in the figure, the original is read upward, and the opened pages of the original are not fixed, and the contact glass 15 moves together with the carriage 4.
If the document 5 is in contact with the document, the spread page of the document may be dragged and damaged, or the read image may have an extended image. Therefore, a clearance is actually provided between the contact glass 15 and the uppermost page of the book document 2. However, due to the clearance, once a foreign matter adheres to the surface of the contact glass 15, the foreign matter is not rubbed against the document, so that the foreign matter is not removed and continues to adhere. There is also a problem that the generation continues until the foreign matter is actively removed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus which can prevent the occurrence of a black stripe-like abnormal image without adhering foreign matter to the effective reading range of the original contact member.

[0008]

According to a first aspect of the present invention, there is provided an image reading apparatus in which an original image surface is turned upward and an original image is placed via an original contact member. An image reading device that irradiates light on a surface and condenses reflected light of the irradiation light on the original image surface to read an original image, wherein an opening is provided in a part of the original contact member, The opening is made larger than the optical path range of the image effective range at the time of image reading.

According to a second aspect of the present invention, the shape of the edge of the opening is a curved surface or an inclined surface.

According to a third aspect of the present invention, the document contact member is opaque.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a cross-sectional view (A) and a plan view (B) showing a main part of an embodiment of the image reading apparatus according to the present invention. The document contacting member 20 according to the present embodiment is entirely formed of an opaque member (such as metal or resin), and has a slit-shaped opening 21 in the center. As shown, the opening 21 is larger than the optical path range of the image effective range at the time of image reading, that is, the effective image area range 22 in the main scanning and sub-scanning directions.

When the flat portion including the effective image area range 22 of the document contact member 20 is deleted as in this embodiment, no foreign matter can adhere to the effective image area range 22 of the document contact member 20. The occurrence of abnormal images such as the above is prevented. Further, among materials generally used as a document contact member, such as glass and plastic, those made of opaque materials are generally inexpensive and easy to process, and therefore are advantageous in terms of cost.

FIG. 4 is a sectional view showing another shape of the opaque document contact member used in the image reading apparatus according to the present invention.
The document contact member 20a in FIG. 4A is made of metal,
A slope 23 is provided at the lower edge of the opening 21 to make it difficult for the end of the original to be caught during a reading operation, thereby reducing the possibility of damage to the original. The document contact member 20b in FIG. 4B is formed by molding resin, and the lower edge of the opening 21 is provided with a curved slope 24 so as to make it difficult to catch the edge of the document. Further, the original contact member 20c shown in FIG. 4 (C) is made of sheet metal, and rises the edge 25 of the opening 21 in an inclined state so that the end of the original is hardly caught. Of course, the original contact member of the present invention is not limited to such opaque ones.

[0014]

As described above, in the image reading apparatus according to the first aspect, the flat portion of the effective image area range of the document contact member is deleted to form the opening, so that the foreign matter to the document contact member can be removed. There is an effect that adhesion can be prevented and occurrence of an abnormal image such as a black stripe image can be easily prevented.

In the image reading apparatus according to the second aspect, as described above, since the edge of the opening of the document contact member is formed as a curved surface or an inclined surface, the document is hardly caught in addition to the above common effects. Thus, there is an effect that the document breakage rate can be significantly reduced.

In the image reading apparatus according to the third aspect, as described above, by using an opaque material as the document contact member, in addition to the above-mentioned common effects, the manufacturing process is easy and inexpensive. This has the effect of reducing costs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a general structure of a book document reading device provided with a page turning mechanism.

FIG. 2 is an enlarged cross-sectional view showing a periphery of a document contact member of the apparatus shown in FIG.

3A and 3B are a cross-sectional view and a plan view, respectively, showing a main part of an embodiment of the image reading apparatus according to the present invention.

FIG. 4 is a cross-sectional view showing another shape of the opaque document contact member used in the image reading apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus main body 2 Book original 3a, 3b Original table 4 Carriage 5 Carriage case 7 Turning belt 6 Optical system 15 Contact glass 13, 14 Light source 8 Photoelectric element 20, 20a, 20b, 20c Document contact member 21 Opening 22 Effective Image area range 23 Slope of opening 24 Curved slope of opening 25 Edge rising of opening

Claims (3)

[Claims] 1. An original image surface is directed upward, light is applied to the original image surface via an original contact member, and reflected light of the irradiation light on the original image surface is condensed. An image reading device for reading an image, wherein an opening is provided in a part of the document contact member, and the opening is made larger than an optical path range of an image effective range at the time of image reading. 2. The image reading apparatus according to claim 1, wherein the edge of the opening has a curved surface or an inclined surface. 3. The image reading apparatus according to claim 1, wherein said document contact member is opaque.