JPH09270884A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the image quality, without damaging a white reference board by an original. SOLUTION: A contact glass 4a is fitted onto an upper side of a contact image sensor 4 in the image reader, and a contact glass 7 is arranged above the contact glass 4a with a prescribed gap by using a gap member 11. A white reference board 8 is arranged in close contact with the rear side of the contact glass 7, and the contact glass 7 side surface of the white reference board 8 is colored in white. A plane restriction structure 9 to improve flatness of the white reference board 8 is arranged on the rear side of the white reference board 8, and the plane restriction structure 9 is pressed onto the white reference board 8 by a compression spring 10. The contact image sensor 4 reads image of an original 6 being carried between the contact glass 4a and the contact glass 7 by a carrier roller 12 and a carrier follower roller 13 and the original 6, whose image is read, is discharged by a paper discharge roller 14 and a paper discharge follower roller 15.

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, and more particularly to an image reading device which prevents a white reference plate from being scratched by a document.

[0002]

2. Description of the Related Art An image reading apparatus is used in a scanner apparatus, a facsimile apparatus, or the like, and irradiates a conveyed original document with light, and photoelectrically converts light reflected from the original document.
Read the image on the original.

A conventional image reading apparatus generally reads a white reference plate provided on the opposite side of the reading position of the original from the reading means before the original is read to obtain the absolute white density and uneven density during reading. Get the standard shading data,
The white reference is determined based on the acquired shading data, the shading correction is performed, and the white reference plate is pressed in the document direction by the floating prevention spring.
The original is prevented from floating on the reading surface.

However, when the document is conveyed while being pressed against the reading surface by the white reference plate, the white reference plate is scratched by the document, or the toner on the back surface of the document adheres to the white reference plate to contaminate it. There was a problem that data could not be obtained and the image quality deteriorated.

In order to solve such a problem, conventionally,
For example, there is an image reading device described in Japanese Patent Laid-Open No. 5-63924. This image reading apparatus includes a holding member having a reading surface, a conveying unit that conveys a document to the reading surface,
The document is arranged on the non-reading surface side of the holding member, and has a document for irradiating the document conveyed to the reading surface with light, and a reading unit for receiving reflected light from the document and reading an image of the document. In the image reading device, at a position facing the reading surface of the holding member, the document is inclined so that the upstream side in the conveying direction of the document is not in contact with the reading surface and the downstream side is in elastic contact with the reading surface. A sheet-like pressing member is provided, and the pressing member is provided with a reference color that serves as a reference when the reading unit reads.

According to this image reading apparatus, since the document is pressed by the elastic force of the pressing member itself, which is not so large,
It is possible to prevent the toner, the paper powder, and the like attached to the original from attaching to the white reference plate.

[0007]

However, in such a conventional image reading mechanism, since the original is always pressed against the reading surface by the white reference plate, the original and the white are not. Due to the contact of the reference plate, the white reference plate is scratched or soiled, and when the white reference plate is read, it is not possible to obtain appropriate shading data, and black streaks or white streaks occur and the image quality deteriorates. There was a problem.

Therefore, in the image reading apparatus according to the first aspect of the present invention, a transparent member having a predetermined hardness is provided on the opposite side of the reading means with the original conveying path interposed therebetween, and a predetermined gap sufficient for conveying the original. A white reference member is provided on the side opposite to the reading means of the transparent member so that the original and the white reference member do not come into direct contact with each other and scratches or stains are attached to the white reference member by the original. It is an object of the present invention to provide an image reading apparatus capable of preventing the above-mentioned problem, performing an appropriate shading correction, and improving the image quality.

According to another aspect of the image reading apparatus of the present invention, the white reference member is formed of a white pressure plate having a predetermined thickness, and the flatness of the white pressure plate is improved on the surface of the white pressure plate opposite to the reading means. By disposing the flatness regulating member, the flatness of the white reference member can be improved, uniform white reference data with less unevenness can be obtained, and more appropriate shading correction can be performed.
It is an object of the present invention to provide an image reading device capable of further improving image quality.

In the image reading apparatus according to the third aspect of the present invention, the surface of the transparent member opposite to the reading means is white-painted to form a white reference member, so that the white reference member is provided between the white reference member and the transparent member. It is an object of the present invention to provide an image reading apparatus capable of preventing foreign matters such as dust and dirt from entering, reducing the number of parts, and being inexpensive and further improving image quality.

[0011]

According to another aspect of the present invention, there is provided an image reading apparatus which irradiates a document conveyed to a reading position with light, and reflects the light from the document to form an image of the document. Reading means for reading, conveying means for conveying the original document to the reading position, discharging means for conveying and discharging the original document whose image has been read by the reading means, and the reading means at a position facing the reading means. A transparent member having a predetermined hardness that guides the original conveyed to the reading position while pressing the original conveyed to the reading position toward the reading unit, and the reading unit of the transparent member. A white reference member disposed on the opposite side, at least the surface on the side of the reading unit being provided in white for providing white reference data; and a reading unit disposed between the reading unit and the transparent member. The above By providing a gap forming means for forming a predetermined gap between the light member, it has achieved the above objects.

According to the above construction, a transparent member having a predetermined hardness is provided on the opposite side of the reading means with the original conveying path interposed therebetween, and a transparent member having a predetermined hardness is disposed. Since the white reference member is provided on the side opposite to the reading means, it is possible to prevent the original and the white reference member from directly contacting each other, and it is possible to prevent the white reference member from being scratched or stained by the original. it can. As a result, appropriate shading correction can be performed, and the image quality can be improved.

In this case, for example, as described in claim 2, a white pressure plate having a predetermined thickness is used as the white reference member, and the white pressure plate is provided on the surface opposite to the reading means. A plane regulating member that improves the flatness of the pressure plate may be provided.

According to the above construction, the white reference member is formed of the white pressure plate having a predetermined thickness, and the plane regulating member for improving the flatness of the white pressure plate is arranged on the surface of the white pressure plate opposite to the reading means. Since the white reference member is provided, the flatness of the white reference member can be improved, and uniform white reference data with less unevenness can be obtained. As a result, more appropriate shading correction can be performed, and the image quality can be further improved.

Further, for example, as described in claim 3, the white reference member may be formed by applying white coating on a surface of the transparent member opposite to the reading means.

According to the above construction, the surface of the transparent member opposite to the reading means is white-painted to form the white reference member. Therefore, dust, dust, or the like is formed between the white reference member and the transparent member. It is possible to prevent foreign matter from entering, reduce the number of parts, make the image reading device inexpensive, and further improve the image quality.

[0017]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

1 to 3 are views showing an embodiment of an image reading apparatus of the present invention, and this embodiment is applied to an image reading apparatus using a contact image scanner.

FIG. 1 is a side view of a main portion of an image reading apparatus 1 to which an embodiment of the image reading apparatus of the present invention is applied. In FIG. 1, the image reading apparatus 1 includes a document feeding section 2 and a document reading unit. It comprises a part 3.

In FIG. 1, the document reading unit 3 of the image reading apparatus 1 is provided with a contact image sensor (reading means) 4, and the contact image sensor 4 has a contact glass 4a attached to the upper surface thereof. . The contact-type image sensor 4 is a document feeding path (indicated by the arrow line in FIG. 1)
By irradiating the original 6 conveyed on the contact glass 4a to the reading position on the contact glass 4a with light and photoelectrically converting the reflected light, the image of the surface (original surface) of the original 6 on the contact glass 4a side is displayed. read.

As shown in FIGS. 2 and 3, on the side opposite to the contact type image sensor 4 with the document feeding path 5 interposed therebetween, the contact glass 4a of the contact type image sensor 4 is provided with a predetermined hardness. The contact glass 7 as a transparent member having a
A white reference plate (white reference member) 8 which is a pressure plate having a predetermined thickness is disposed in close contact with the back surface (the surface opposite to the contact image sensor 4) of the. White reference plate 8
Has a surface (white reference surface) on the side of the contact glass 7 that is white for providing white reference data when the document 6 is read.

A plane regulating structure 9 is provided on the surface of the white reference plate 8 opposite to the contact glass 7, and a flat regulating structure 9 is provided on the surface of the plane regulating structure 9 opposite to the white reference plate 8. Pressure spring 1
0 is attached. The other end of the pressure spring 10 is fixed to a frame or the like of the image reading device 1 (not shown). The plane regulation structure 9 has a predetermined flatness, and by pressing the white reference plate 8 against the contact glass 7, the white reference plate 8 is pressed.
Improves the flatness of.

A gap member 11 is provided between the contact glass 4a and the contact glass 7 of the contact type image sensor 4 and a contact glass 4a and the contact glass 7 are provided.
The contact glass 4a and the contact glass 7 pass through the contact glass 4a while the normal original 6 is in close contact with the contact glass 4a. A possible gap δ, for example 0.35 mm, is formed.

The contact glass 7, the white reference plate 8 and the plane regulation structure 9 are integrally fixed, and the pressure spring 10 is a predetermined urging force, for example, a document thicker than the gap δ. When the original document 6 is conveyed through the original document conveyance path 5, the contact glass 7, the white reference plate 8, and the plane regulating structure 9 are moved upward by the original document 6 without disturbing the conveyance of the original document 6 and the thick original document. The plane restricting structure 9 is biased by a biasing force suitable for passing 6 appropriately.

Therefore, the contact glass 7 and the white reference plate 8 are urged toward the contact image sensor 4 by the pressure spring 10 via the plane regulating structure 9, and the contact glass 7 is moved to the gap member 11. By contacting the contact type image sensor 4, the contact type image sensor 4 is held at the shading position in a state of being close to the contact type image sensor 4, and when the document 6 thicker than the gap δ is conveyed, the contact type image sensor 4 is conveyed. The thick original document 6 can be conveyed by moving in a direction away from.

Referring again to FIG. 1, the document reading section 3 of the image reading apparatus 1 is provided with the contact image sensor 4 between them, and the feeding roller 1 is provided on the upstream side (the right side in FIG. 1) of the document 6 in the feeding direction.
2 and a conveyance driven roller 13 that comes into contact with the conveyance roller 12, and a paper ejection roller 14 and a paper ejection driven roller 15 that comes into contact with the paper ejection roller 14 are provided on the downstream side (the left side in FIG. 1) of the document 6 in the conveyance direction. It is arranged. The transport roller 12 and the paper discharge roller 14 are rotationally driven by a drive motor (not shown). The transport roller 12 and the transport driven roller 13 function as a transport unit that transports the document 6 to the reading position, and the paper discharge roller 14
The paper discharge driven roller 15 functions as a discharge unit that discharges the document 6 whose image is read by the contact image sensor 4.

A plurality of originals 6 are placed on the original placing table 16 of the original feeding section 2, and the originals 6 on the original placing 16 are picked up by the pickup roller 17 and sequentially from the lowermost original by the pickup roller 17. Feed roller 18
And the separation roller 19 between them. The originals 6 sent out between the feed roller 18 and the separation roller 19 are separated one by one by the feed roller 18 and the separation roller 19, and are brought into contact with the conveyance roller 12 and the conveyance driven roller 13 on the original conveyance path 5. Sent out.

The carrying roller 12 works together with the carrying driven roller 13 to carry the document 6 carried from the document placing table 16 between the contact glass 4a and the contact glass 7 of the contact-type image sensor 4 and contact-type. The image sensor 4 has a document 6 conveyed on the contact glass 4a.
The image on the surface (original surface) on the contact image sensor 4 side is read. The document 6 whose image has been read by the contact image sensor 4 is conveyed by the conveyance roller 12 and the conveyance driven roller 13, and when the leading end of the conveyance roller 12 and the conveyance driven roller 13 reaches the ejection roller 14, the ejection roller 14 and the ejection driven roller 15 As a result, the sheet is conveyed and discharged to a sheet discharge tray (not shown).

Next, the operation will be described. Image reading device 1
When reading the document 6, first, the contact image sensor 4
The white reference plate 8 is read by and the shading data is acquired.

At this time, since the white reference plate 8 is pressed against the contact glass 7 by the plane regulating structure 9, its flatness is improved and uniform white reference data (shading data) is obtained. be able to. As a result, appropriate shading correction can be performed, and the image quality of the image read by the contact image sensor 4 can be improved.

When the image reading apparatus 1 performs this shading, the drive motor is rotationally driven to pick up the lowermost original 6 placed on the original placing table 16 by the pickup roller 17 and the feed roller 18 and the separating roller 19. And the feed roller 18 is separated together with the separation roller 19 one by one, and is fed on the document feeding path 5 along the feeding roller 1.
2 and the conveying driven roller 13 are sent to the contact portion. The transport roller 12 cooperates with the transport driven roller 13 to transport the document 6 between the contact glass 4 a and the contact glass 7 of the contact image sensor 4, and the contact image sensor 4
Reads the image of the document 6 conveyed on the contact glass 4a.

At this time, the contact glass 7 is disposed on the contact glass 4a of the contact image sensor 4 with the gap member 11 interposed therebetween, and the contact glass 7 has a white surface on the side opposite to the contact image sensor 4. Since the reference plate 8 is provided, it is possible to prevent the white reference plate 8 from being damaged by the original 6 and to prevent the toner or the like on the back surface of the original 6 from adhering to the white reference plate 8. As a result, appropriate shading correction can be performed, and the image quality of the image read by the contact image sensor 4 can be improved.

Further, since the gap member 11 is disposed between the contact glass 4a and the contact glass 7 of the contact image sensor 4, the original surface of the original 6 is kept in contact with the contact glass 4a without clogging the original 6. The sheet can be smoothly conveyed in a state of being closely contacted with, and the image can be read appropriately.

In this way, the contact image sensor 4
The document 6 whose image has been read by is further transported by the transport roller 12 and the transport driven roller 13, and
The sheet is discharged to a sheet discharge tray (not shown) by the sheet discharge roller 14 and the sheet discharge driven roller 15.

When the original 6 is thicker than the gap δ between the contact glass 4a formed by the gap member 11 and the contact glass 7, the contact glass 7, the white reference plate 8 and the plane regulating structure 9 are integrally biased. Pressurizing spring 1
Since the biasing force of 0 is set appropriately, the contact glass 7, the white reference plate 8 and the plane regulating structure 9 are set by the document 4.
Can be moved upward to properly convey the original 6, and the original 6 having a large paper thickness can also be appropriately read.

As described above, the invention made by the inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

For example, in the above embodiment, the white reference plate 5 of the pressure plate is used as the white reference member, but the white reference member is not limited to the white reference plate 5, and for example, the contact glass 7 may be used. It may be formed by applying a white coating on the back surface (the surface opposite to the contact image sensor 4). In this case, foreign matter such as dust or dust is left between the contact glass 7 and the white reference plate. It is possible to prevent the entry and further improve the image quality, reduce the number of members, and make the image reading apparatus inexpensive.

In the above embodiment, the case where the contact type image sensor is used as the reading means has been described, but the reading means is not limited to the contact type image sensor, and for example, a reduction optical system is used. The same can be applied to the above image sensor.

[0039]

According to the image reading apparatus of the first aspect of the present invention, a transparent material having a predetermined hardness and a predetermined hardness sufficient to convey a document is provided on the opposite side of the reading means with the document conveying path interposed therebetween. Since the white reference member is provided on the opposite side of the transparent member from the reading means, the original and the white reference member can be prevented from directly contacting each other, and the white reference member is not damaged by the original. It is possible to prevent dirt and the like from being attached. As a result, appropriate shading correction can be performed, and the image quality can be improved.

According to the image reading apparatus of the second aspect, the white reference member is formed of a white pressure plate having a predetermined thickness, and the flatness of the white pressure plate is provided on the surface of the white pressure plate opposite to the reading means. Since the flatness regulating member that improves the white reference member is disposed, it is possible to improve the flatness of the white reference member and obtain uniform white reference data with less unevenness. As a result, more appropriate shading correction can be performed, and the image quality can be further improved.

According to the image reading apparatus of the third aspect of the invention, since the white reference member is formed by applying white coating on the surface of the transparent member opposite to the reading means, the white reference member and the transparent member are formed. It is possible to prevent foreign matter such as dust and dust from entering between the parts, reduce the number of parts, and make the image reading device inexpensive.
The image quality can be further improved.

[Brief description of drawings]

FIG. 1 is a side partial cross-sectional view of a main part of an image reading apparatus to which an embodiment of the image reading apparatus of the present invention is applied.

FIG. 2 is an enlarged front sectional view of the contact image sensor portion of FIG.

FIG. 3 is an enlarged side sectional view of the contact image sensor portion of FIG.

[Explanation of symbols]

 1 Image Reading Device 2 Document Feeding Unit 3 Document Reading Unit 4 Contact Image Sensor 4a Contact Glass 5 Document Transport Path 6 Document 7 Contact Glass 8 White Reference Plate 9 Plane Regulation Structure 10 Pressure Spring 11 Gap Member 12 Transport Roller 13 Transport Driven roller 14 Paper output roller 15 Paper output driven roller 16 Original platen 17 Pickup roller 18 Feed roller 19 Separation roller

Claims (3)

[Claims] 1. A reading unit that irradiates a document conveyed to a reading position with light and reads an image of the document by reflected light of the document, and a conveying unit that conveys the document to the reading position. And a discharge unit for conveying and discharging the document whose image has been read by the reading unit, and a position opposed to the reading unit so as to be movable by a predetermined amount in a direction away from the reading unit. A transparent member having a predetermined hardness that guides the original conveyed to the reading unit while pressing the original, and a transparent member disposed on the opposite side of the transparent member from at least the reading unit side. A white reference member provided in white for providing reference data, and a gap forming means disposed between the reading means and the transparent member to form a predetermined gap between the reading means and the transparent member. When, Image reading apparatus characterized by comprising. 2. A white pressure plate having a predetermined thickness is used as the white reference member, and a flatness regulating member for improving the flatness of the white pressure plate is arranged on a surface of the white pressure plate opposite to the reading means. The image reading apparatus according to claim 1, wherein the image reading apparatus is provided. 3. The image reading apparatus according to claim 1, wherein the white reference member is formed by applying white coating on a surface of the transparent member opposite to the reading unit.