JP2000134417A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably feed a sheet origin and to prevent the sheet original from being adsorbed electrostatically onto the surface of a contact image sensor(CIS) by making a guide member covering a gap between a read means and a carrying guide member of a metallic plate, and connecting the plate electrically to ground thereby reducing the feeding resistance of the sheet original. SOLUTION: A metal-made CIS mount plate 11 fixes a CIS 6 connecting electrically to ground to a main body. An input guide plate 10 whose width is wider than that of a sheet original P at an upper-stream of the CIS 6 and which is placed at an entrance of an original read section 4 is made of a metallic plate whose surface is smooth such as a stainless steel plate and is fixed to the CIS mount plate 11 to connect itself electrically to ground. Since the entrance guide plate whose surface is smooth such as a stainless steel plate is fixed to the CIS mount plate 11 in this way, a friction resistance of this part on a carrying face of the sheet original P is lower to reduce the feeding resistance. Even when the sheet original P charged with static electricity is fed, the statictricity is removed by the electrically grounded entrance guide plate 10.

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 image information on a sheet document, and more particularly to an image reading section.

[0002]

2. Description of the Related Art Conventionally, the configuration around an image reading section (contact image sensor, hereinafter referred to as CIS) of an image reading apparatus for reading image information of a sheet document is as shown in FIG.

In FIG. 5, P is a sheet document, and 51 is a feed separation unit of a lower separation system for feeding the documents P one by one into the image reading apparatus. Reference numeral 52 denotes a transport roller for transporting and inserting a sheet document into the CIS at a stable speed; 53, a transport guide plate for guiding the sheet document P to the transport roller 52;
Is a leading edge detection sensor for detecting the leading edge of the sheet document, 55 is a CIS for reading image information of the sheet document that is in close contact, 56
Reference numeral 57 denotes an image reading unit of the CIS 55 for reading image information; 57, a conveyance guide plate for guiding the document P to the image reading unit 56;
Reference numeral 8 denotes a pressing plate for bringing the sheet document P into close contact with the CIS 55 by a spring force and its own weight; 59, a discharge roller for reliably discharging the sheet document P to the outside of the apparatus; 60, the sheet document P from the image reading unit 56 to the discharge roller 59; It is a discharge guide to guide.

The sheet document P is fed and separated by a feed / separation unit 51 of the image reading apparatus, and after passing through a conveying roller 52,
After the leading edge of the sheet document is detected by the leading edge detecting sensor 54, the image reading unit 56 between the CIS 55 and the pressing plate 58
Are sequentially fed one by one along the transport guide plates 53 and 57 while keeping the distance between the sheet documents constant.

[0005] The sheet document P sent along the transport guide plates 53 and 57 is sandwiched between the CIS 55 and the pressing plate 58, and image information on the sheet document is read by an image reading section of the CIS 55, and the electrical information is read. Converted to a signal.
The converted electric signal is processed by an output signal processing circuit (not shown), and thereafter, the sheet document P is discharged to the outside of the image forming apparatus by the discharge roller 59.

[0006]

In the above-mentioned conventional image reading apparatus, the connecting portion between the transport guide plate 57 and the CIS 55 forms a guide surface on the casing of the CIS 55 or the plastic transport guide plate 57. CI at the end
It extends to the entrance of S55 and overlaps,
Alternatively, as shown in FIG. 5, a synthetic resin sheet 61 such as polyethylene terephthalate is attached to the rear end of the transport guide plate 57, and the synthetic resin sheet 61 overlaps the entrance of the CIS 55.

However, in the configuration around the image reading section as described above, depending on the attitude of the sheet document after the sheet document has passed the leading edge detection sensor, the transport guide plate 57 and the CI
The document conveyance resistance of the connection portion in S55 increases, and the reading timing in the image reading unit 56 is shifted, which causes a problem in stably conveying the sheet document to the image reading unit 56.

In addition, static electricity is easily generated during conveyance of a sheet document.
A reading error occurs in S55, or in the worst case CIS55
Had to be destroyed.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the quality of an image reading apparatus by making it possible to stabilize sheet document transport performance without impairing the CIS reading performance. It is.

[0010]

An image reading apparatus according to the present invention has been made in view of the above circumstances, and includes reading means for reading image information on a sheet document, conveying means for conveying the sheet document, and A transport guide member for guiding the sheet document transported by the transport unit to the reading unit; and a guide member for covering a gap between the reading unit and the transport guide member, wherein the guide member is electrically grounded. It is characterized by having.

An image reading apparatus according to the present invention has been made in view of the above circumstances, and includes reading means for reading image information on a sheet document, conveying means for conveying the sheet document, and conveyance by the conveying means. A conveyance guide member for guiding the sheet document to be read to the reading unit, and a guide member fixed to the conveyance guide member and covering a gap between the reading unit and the conveyance guide member, wherein the guide member includes:
It is characterized by being electrically grounded.

Further, an image reading apparatus according to the present invention has been made in view of the above circumstances, and includes a reading means for reading image information on a sheet document, a conveying means for conveying the sheet document, and the reading means. And a transport guide member that guides a sheet document transported by the transport unit to the reading unit by filling a gap between the transport guide members.
It is characterized by being electrically grounded.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a cross-sectional configuration around a CIS of an image reading apparatus for reading image information of a sheet document.

In FIG. 1, reference numeral 1 denotes an image reading unit for reading image information of a sheet document.

P is a sheet document and 2 is a sheet document P
This is a feed separation unit of a lower separation system for feeding sheets one by one.

Reference numeral 3 denotes a transport roller pair for transporting the sheet document to the image reading section 4, and reference numeral 5 denotes a leading edge detection sensor for detecting the leading edge position of the sheet document.

Reference numeral 6 denotes a CIS including a substrate having a semiconductor light receiving element, a rod lens array, an LED for illumination, a light receiving element driving circuit, an output signal processing circuit, and the like in a housing for reading image information of a sheet document.

Reference numeral 7 denotes a pressing plate for bringing the sheet document P into close contact with the image reading section 4 by its own weight and spring force, and reference numeral 8 denotes a discharge roller for discharging the sheet document P to the outside of the image reading apparatus.

Reference numeral 9 denotes a conveying guide plate for conveying and guiding the sheet document P to the image reading unit 4. Reference numeral 10 denotes an entrance guide plate which is disposed upstream of the CIS at an entrance of the document reading unit 4 and which is wider than the sheet document. This is a metal CIS mounting plate for fixing the electrically grounded CIS 6 to the apparatus body.

In the first embodiment, the entrance guide plate 10 is made of a metal plate having a smooth surface such as a stainless steel plate, and is fixed to the CIS mounting plate 11 to be electrically grounded.

FIG. 2 is an enlarged sectional view showing the image reading unit 1 in an enlarged manner.

Since the entrance guide plate 10 having a smooth surface, such as a stainless steel plate, is fixed to the CIS mounting plate 11, the frictional resistance of the conveying surface of the sheet document P at this portion is reduced, and the conveying resistance is reduced. .

Also, even if a sheet document charged with static electricity is conveyed, or the sheet document P is charged during transport, the sheet document P is removed by the entrance guide plate 10, so that the sheet document P is placed on the surface of the CIS 6. Electrostatic attraction can be prevented, and reading errors can be prevented.

Further, it is possible to prevent the light receiving element and the output signal processing circuit inside the CIS from being abnormal or destroyed due to static electricity on the sheet document P.

In the first embodiment, the entrance guide plate 10 is made of a metal plate having a smooth surface such as a stainless steel plate. However, a sheet metal whose surface is plated or a plastic plate whose surface is plated is used. You may use a board,
Further, a sheet having excellent surface conductivity and an extremely small surface friction coefficient may be electrically grounded and attached to a suitable plate.

The entrance guide plate 10 may be independently grounded.

(Embodiment 2) Embodiment 2 according to the present invention will be described with reference to the drawings.

FIG. 3 is a diagram showing a cross-sectional configuration around the CIS of an image reading apparatus for reading image information of a sheet document according to the second embodiment.

In FIG. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

In the second embodiment, the entrance guide plate 12 is attached to the conveyance guide plate 9 of the sheet original by screws 13 and is brought into contact with the electrically grounded CIS attachment plate 11 to be grounded. .

With this configuration, the positions of the entrance guide plate 9 and the conveyance guide plate 9 with respect to the original reading surface can be easily regulated, so that the conveyance of the sheet original P can be stabilized.

(Third Embodiment) Next, a third embodiment according to the present invention will be described with reference to the drawings.

FIG. 4 is a diagram showing a cross-sectional configuration around the CIS of an image reading apparatus for reading image information of a sheet document according to the third embodiment.

In FIG. 4, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

In the third embodiment, the entrance guide plate 14 also serves as a transport guide plate, and is abutted against the CIS mounting plate 11 to be electrically grounded.

With this configuration, the entrance guide plate 14 also serves as the transport guide plate, and can easily be grounded and positioned with respect to the CIS, thereby simplifying the component configuration.

[0038]

As described above, according to the present invention,
By providing an entrance guide plate made of a low friction metal plate with a smooth surface such as a stainless steel plate on the upstream side of the CIS housing, the conveyance resistance of the sheet document is reduced and the conveyance can be stabilized. Was.

Even if a sheet document charged with static electricity is conveyed, or a sheet document charged with static electricity is conveyed during the conveyance, the entrance guide plate which is grounded can be used.
The static electricity can be removed, the sheet document can be prevented from being electrostatically attracted to the CIS surface, and reading error of image information on the sheet document can be prevented.

Further, it is possible to prevent abnormalities or destruction of the light receiving element and the output signal processing circuit inside the CIS due to the static electricity on the sheet document.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cross-sectional configuration around a CIS of an image reading apparatus that reads image information of a sheet document according to a first embodiment.

FIG. 2 is an enlarged cross-sectional view in which an image reading unit 1 is enlarged.

FIG. 3 is a diagram illustrating a cross-sectional configuration around a CIS of an image reading apparatus that reads image information of a sheet document according to a second embodiment.

FIG. 4 is a diagram illustrating a cross-sectional configuration around a CIS of an image reading apparatus that reads image information of a sheet document according to a third embodiment.

FIG. 5 is a diagram illustrating a cross-sectional configuration around a CIS of a conventional image reading apparatus that reads image information of a sheet document.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading unit 2 Feed separation part 3 Conveyance roller pair 4 Image reading part 5 Edge detection sensor 6 Contact image sensor (CIS) 7 Press plate 8 Discharge roller 9 Transport guide plate 10 Inlet guide plate 11 CIS mounting plate

Claims (12)

[Claims] A reading unit that reads image information on a sheet document; a conveying unit that conveys the sheet document; a conveyance guide member that guides the sheet document conveyed by the conveying unit to the reading unit; And a guide member for covering a gap between the transport guide member, wherein the guide member is electrically grounded. 2. The image reading apparatus according to claim 1, wherein the guide member is formed of a smooth metal plate. 3. The image reading apparatus according to claim 2, wherein said guide member is formed of a stainless steel plate. 4. The image reading apparatus according to claim 1, wherein the guide plate is a synthetic resin plate having a surface plated. 5. The image reading apparatus according to claim 1, further comprising: a mounting member that electrically grounds the reading unit and that is attached to the image reading apparatus main body, wherein the guide member is electrically grounded by being fixed to the mounting member. The image reading device according to claim 1, wherein: 6. A reading device for reading image information on a sheet document, a conveying device for conveying the sheet document, a conveyance guide member for guiding the sheet document conveyed by the conveying device to the reading device, An image reading apparatus, comprising: a guide member fixed to a guide member and covering a gap between the reading unit and the transport guide member, wherein the guide member is electrically grounded. 7. The image reading apparatus according to claim 6, wherein the guide member is formed of a smooth metal plate. 8. The image reading apparatus according to claim 7, wherein said guide member is formed of a stainless steel plate. 9. The image reading apparatus according to claim 6, wherein said guide member is a synthetic resin plate having a surface subjected to a plating process. 10. An image reading apparatus further comprising: an attachment member electrically grounding the reading means and attaching to the image reading apparatus main body.
The image reading apparatus according to claim 6, wherein the guide member is electrically grounded by being abutted against the mounting member. 11. A reading means for reading image information on a sheet document, a conveying means for conveying the sheet document, and a sheet document conveyed by the conveying means by filling a gap between the reading means and the reading means. And a transport guide member for guiding the transport guide member, wherein the transport guide member is electrically grounded. 12. The image reading apparatus according to claim 12, further comprising: a mounting member that electrically grounds the reading unit and attaches the reading unit to an image reading apparatus main body.
The image reading apparatus according to claim 11, wherein the conveyance guide is electrically grounded by being fixed to the mounting member.