JP2007201730A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader for restraining an influence caused by flare when reading an original. <P>SOLUTION: The image reader comprises contact glass having a read region for which the original is read and a non-read one for which no originals are read; a light source for emitting light onto the original placed on the read region; and a light reception means for receiving light that is reflected by the original and comes from the light source. The image reader has a non-reflection structure for reducing the reflection of light from the light source as compared with the read region, in a flare generation region that is the non-read region and receives the irradiation of light from the light source. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, and more particularly, to an image reading apparatus that suppresses the influence of flare during document reading.

  For example, due to a demand for reducing the area of an office or the like, downsizing of an image reading apparatus such as a scanner is required. Along with this, the internal structure of the image reading apparatus is forced to have a structure with little space and space. In a structure having a small optical margin, reflection of light that has not been affected in the past has affected reading of an image.

In addition, in order to suppress the influence of the flare, the reflected light which is not intended is referred to as flare. Thus, a configuration that eliminates unintentional light reception is disclosed.
JP-A-6-90328

Below, the flare problem associated with downsizing is specifically shown.
FIG. 5 shows a part of a general image reading structure. A document 501 placed on a contact glass 502 is irradiated with light from a light source 504 constituting a movable carriage 503 and reflected light thereof. Is reflected by the reflecting mirror 506 through the slit 505. When the reflected light is received by a light receiving element (not shown), the document 501 is read as an image.

In the above processing, the dotted line arrow shows an example of the optical path, but the light from the light source 504 is reflected on the non-reading area 507 on the contact glass 502, which is not related to the reading of the document, and the slit 505 Reflected also in the vicinity of the edge 508, the original surface is irradiated again.
FIG. 6 shows the read image density when flare occurs. FIG. 6 shows the image density in the vicinity of the document edge when a document having the same density on the entire surface is read. The larger the value on the Y axis, the brighter the image. That is, despite the same density on the entire surface, the image density (approximately 50 to slightly less than 60) from the edge of the document to approximately 100 pixels (approximately 4 cm) is higher than that of the document center (approximately 40 or more). Can be read.
By the way, it can be said that it is difficult to apply the above-described conventional technique to the above-described flare problem associated with downsizing. In other words, the above-described configuration for the purpose of downsizing has a small space margin, for example, there is not enough margin to arrange a plate-like member between the light source and the document. Naturally, the problem of the cost increase by the said plate member also arises. Further, the above-described conventional technique mainly prevents an adverse effect of reflected light from the edge direction of the slit (sub-scanning direction during document scanning), and prevents reflected light from the longitudinal direction (scanning direction) of the slit. There is also the problem that it cannot be done.

  The present invention has been proposed to solve the above-described conventional problems, and an object of the present invention is to provide an image reading apparatus in which the influence of flare at the document edge during document reading is suppressed.

  The present invention employs the following means in order to achieve the above object. In other words, an image reading apparatus according to the present invention includes a contact glass including a reading area that is a reading target of a document and a non-reading area that is not a reading target of the document, and a light source that irradiates light on the document placed in the reading area. And light receiving means for receiving light from the light source reflected by the document. The flare generation area that is a non-reading area and is irradiated with light from the light source has a non-reflective structure that reduces the reflection of light from the light source as compared with the reading area.

  With the non-reflective structure, the influence of flare can be suppressed and the amount of reflected light at both ends and the center of the document can be made uniform, that is, an image of the document can be acquired accurately.

The non-reflective structure can be implemented by coloring the flare generation region with a non-reflective color that reflects less light than the reading region. As the non-reflective color, black, gray, dark colored or similar colors can be applied.
Moreover, when a light source irradiates colored light, a non-reflective structure is good also as coloring of the complementary color corresponding to colored light to a flare generation | occurrence | production area | region.

  In addition, when the contact glass and the document placement plate are provided with a document placement plate indicating a reference for placing the document in a non-reading region on the document placement surface of the contact glass and receiving the light source from the irradiation surface, Flare can also be prevented by bonding with an adhesive means having a non-reflective color that reflects less light than the reading area.

  This configuration is advantageous in terms of manufacturing efficiency because the adhesive means is merely made a non-reflective color without changing the conventional manufacturing procedure.

  Further, the same effect can be expected when the non-reflective structure is converted to ground glass of the contact glass corresponding to the non-reading region.

The influence of flare can be suppressed and the amount of reflected light at both ends and the center of the document can be made uniform, that is, the image of the document can be obtained accurately.
Moreover, flare can be prevented by bonding the contact glass and the document placement plate with an adhesive means having a non-reflective color that reflects less light than the reading area. Since only the non-reflective color is used for the adhesive means without any change, it is advantageous in terms of manufacturing efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

  The image reading apparatus according to the present invention corresponds to, for example, a scanner, a copier, a fax machine, or a multifunction machine including these.

  The configuration of the scanner will be briefly described as an example of the image reading apparatus. FIG. 1 is a side view illustrating a schematic configuration of the image reading apparatus 101. As shown in FIG. 1, the image reading apparatus 101 includes a mounting table 102, a mounting table cover 103, a first moving carriage 104, a second moving carriage 108, a lens group 111, and a light receiving element 112 that functions as a light receiving unit. is doing.

  Further, the first moving carriage 104 includes a light source 105, a slit 107 that allows the light emitted from the light source to be reflected on the document surface, and a first carriage reflection mirror 106 that reflects the light received through the slit. It has.

  The second moving carriage 108 includes second carriage reflection mirrors 109 and 110 that reflect the reflected light from the first carriage reflection mirror 106.

  FIG. 2 is a schematic top view of the image reading apparatus, and is a view from above of the image reading apparatus in a state where the mounting table cover 103 is omitted. 3 is a cross-sectional view of the image reading apparatus in the scanning direction (near A-A ′ in FIG. 2).

  The mounting table 102 includes a contact glass 301 and document placing plates 201 and 202 provided on a document reading surface (upper surface) of the contact glass 301. The document placing plates 201 and 202 are disposed on the contact glass 301 and in a non-reading area that is not a reading target of the document. Not subject. Further, an area indicated by a broken line 203 in FIG. 2 where the original placing plates 201 and 202 are not provided can be an original reading area 203. The reading area is an area to be read from the original.

  Now, based on the above configuration, a process for reading an original by the image reading apparatus 101 will be described.

  When the image reading apparatus 101 reads an original, the original reading surface is arranged to face the original reading surface of the mounting table 102. At this time, the document is placed so that the corner of the document matches the reference point 113 defined by the document placing plate 201 that is a convex portion with respect to the contact glass 301. When the reading process is started after the original is placed and the mounting table cover 103 is attached to the upper part of the original (the state shown in FIG. 1), the first moving carriage 104 moves below the scanning line including the reference point 113.

  Subsequently, the light source 105 on the first moving carriage 104 irradiates the original with light from the irradiation surface direction which is the lower surface of the contact glass 301. The irradiated light is reflected on the reading surface of the original according to its density, and is reflected by the first carriage reflecting mirror 106 through the slit 107.

  The light reflected by the first carriage reflection mirror 106 is sequentially reflected by the second carriage reflection mirrors 109 and 110 constituting the second carriage 108, so that the optical path is changed and received through the lens group 111. Light is received by the element 112.

  When the reflected light of the document is received by the light receiving element 112, the light receiving element 112 converts the received light into an electrical signal, and thereby, for example, an image for one line in the scanning direction of the document is digitized.

  The first carriage 104 moves in the sub-scanning direction, and the light received based on the movement is converted as needed, so that the entire reading surface of the document placed in the reading area 203 is digitized and used as image information. To be acquired.

  The acquired image information is stored in, for example, a storage unit (not shown), and is transmitted to other devices or other processing units as necessary.

  In such an image reading apparatus 101, as shown in FIG. 3, the areas 302A and 302B corresponding to the non-reading areas on the contact glass 301 irradiation surface are not read. Since light is irradiated, it becomes a cause of flare, that is, it can be a flare generation region. The flare occurrence area corresponds to an area on the irradiation surface side of the document placing plates 201 and 202 in FIG.

  Therefore, the image reading apparatus 101 includes a non-reflective structure that reduces the reflection of light compared to the reading area 203 with respect to the flare occurrence area.

  As the non-reflective structure, the flare generation areas 302A and 302B are colored (non-reflective color) so that the reflectance is lower than that of the reading area 203. The coloring is performed, for example, by coloring the non-reading area in black on the irradiation surface of the contact glass 301 or the document placement surface. The coloring may be performed by coloring the paint directly on the contact glass 208, but may be performed by, for example, attaching a non-reflective color adhesive tape or a non-reflective color plate to the flare generation regions 302A and 302B. Furthermore, at least one surface of the document placement plates 201 and 202 that is in contact with the document placement surface may be a non-reflective color. The non-reflective color here refers to black, gray, dark colored, and a color obtained by applying a matte process to these. In the case of a monochrome image reading apparatus, the light source may be designed with, for example, green other than white light. In such a case, for example, red having a complementary color relationship with green can be applied as the non-reflective color. In addition to green light, even when other colors are used, flare can be prevented by using a non-reflective color having a complementary color relationship with the color of the light source.

  Further, it can be said that the use of an adhesive means such as an adhesive tape or the coloring of the document placing plates 201 and 202 is advantageous in terms of cost as compared with coloring with a paint.

  Further, when the contact glass 301 and the document placing plates 201 and 202 are bonded, the non-reflective double-sided tape 303A or 303B is used as the bonding means to prevent the occurrence of flare in the flare generation region. It becomes possible to do. In this case, since only the non-reflective color is used for the bonding means without changing the conventional manufacturing procedure, it is advantageous in terms of manufacturing efficiency.

When the document table 102 having the non-reflective structure is used, as shown by a broken line arrow 304 in FIG. 3, the surface irradiated with the non-reflective structure of the light emitted from the light source 105 to the flare generation region (see FIG. 3). The reflection at the middle (X) is reduced. Due to the reduction of the reflection, the reflected light based on the flare from the longitudinal direction (scanning direction) of the slit does not pass through the slit 107, that is, both end portions in the scanning direction of the original are unnecessarily bright compared to the central portion. This can be prevented.
FIG. 4 is a graph showing the read image density when a black adhesive tape is attached to the flare generation area (irradiation surface side) of the contact glass 208 under the same conditions as in FIG. It can be read that the image density from the edge of the document to about 100 pixels (approximately 45 to slightly less than 50) is darker than that in FIG. 6, that is, a value close to the density at the center of the document (approximately 40) is obtained. .

  That is, the amount of reflected light at both ends and the center of the document is uniform, that is, the image of the document can be accurately acquired while suppressing the influence of flare.

  In addition to the coloring of the non-reflective structure, the above effect can be expected, for example, by grounding the flare generation region of the contact glass.

  The image reading apparatus according to the present invention is useful as an image reading apparatus in which the influence of flare during document reading is suppressed.

FIG. 3 is a side view illustrating a schematic configuration of the image reading apparatus. FIG. 3 is a top view of the image reading apparatus. FIG. 3 is a cross-sectional view of the image reading apparatus in the scanning direction. FIG. 3 is a read image density diagram in the image reading apparatus according to the present invention. Sectional drawing which shows the reflection in the conventional flare generation | occurrence | production area | region. FIG. 6 is a read image density diagram in a conventional image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Image reading apparatus 102 Mounting stand 103 Mounting stand cover 104 1st moving carriage 105 Light source 106 First moving carriage reflective mirror 107 Slit 108 Second moving carriage 109, 110 Second moving carriage reflecting mirror 110 Second moving carriage reflecting mirror 111 Lens Group 112 Light Receiving Element 113 Reference Point 201, 202 Document Placement Plate (Non-Reading Area)
203 Reading area 301 Contact glass 302A, 302B Flare generation area 303A, 303B Double-sided tape

Claims (6)

A contact glass having a reading area to be read of a document and a non-reading area not to be read of the document;
A light source for irradiating light on a document placed in the reading area;
Light receiving means for receiving light from the light source reflected by the document,
An image reading apparatus having a non-reflective structure that reduces reflection of light from the light source in a flare generation region that is irradiated with light from the light source, compared to the reading region.   The image reading apparatus according to claim 1, wherein the non-reflective structure is colored with a non-reflective color with less light reflection in the flare occurrence region than in the reading region.   The image reading apparatus according to claim 2, wherein the non-reflective color is black. When the light source emits colored light,
The image reading apparatus according to claim 1, wherein the non-reflective structure is a complementary color corresponding to the colored light to the flare occurrence region. In the case where the non-reading area on the document placement surface of the contact glass is provided with a document placement plate showing a reference for placing the document, and is irradiated with the light source from an irradiation surface opposite to the placement surface. ,
The image reading apparatus according to claim 1, wherein the contact glass and the document placing plate are bonded by an adhesive unit having a non-reflective color that reflects less light than a reading region. The image reading apparatus according to claim 1, wherein the non-reflective structure is ground glass of contact glass corresponding to the non-reading region.

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