JPH10327296A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader with high reading performance so as to satisfactorily read an original by preventing an optical system from getting out of focus even when reading the original on contact glass either at a 1st reading position or at a 2nd reading position. SOLUTION: The upper surface of 1st contact glass 2 is made lower than the upper surface of 2nd contact glass 3 and the conveying surface of original to be conveyed onto the 1st contact glass 2 is matched with the upper surface of 2nd contact glass 3. Besides, a white guide 17 is arranged so that the lower surface of white guide 17 facing the upper surface of 1st contact glass 2 can become the same height as the upper surface of 2nd contact glass 3.

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 such as a copying machine, a facsimile apparatus, and a scanner, and more particularly, to a first apparatus for reading a document by an optical system stopped below a first reading position while conveying the document. Scan mode and original
The present invention relates to an image reading apparatus having a second reading mode in which a document is read by being placed on a reading position and moving an optical system below the second reading position.

[0002]

2. Description of the Related Art Conventional image reading apparatuses of this type include:
For example, there is one as described in Japanese Utility Model Laid-Open No. 23137/1991. In this apparatus, an automatic document feeder (hereinafter, simply referred to as an ADF) is provided on an upper surface of an image reading device. The ADF separates only one document from a document bundle and transports the document onto a contact glass. A first reading mode for reading an original conveyed by an optical system stopped below the glass, and after opening the ADF and placing the original on the contact glass, the ADF is moved down to the contact glass side to move the optical system. And a second reading mode for reading a document that is stopped.

[0003]

However, in such an image reading apparatus, since the upper surface of the contact glass is located in the same plane, the first reading mode is smaller than that in reading the original in the second reading mode. When reading a document in the reading mode, there is a problem that the focus of the optical system is deviated and the document cannot be read properly.

That is, when a document is read in the first reading mode, the focus of the optical system is provided so as to face the contact glass in the first reading mode, and forms a part of the document transport path together with the contact glass. It is adapted to the guide member. This is because, when reading a document in the second reading mode, the document is placed on the contact glass and stopped, whereas when reading the document in the first reading mode, the document is placed on the contact glass and the guide. This is because the document is transported above the contact glass when transported between the members.

When the original is read in the first reading mode and the second reading mode, the focus of the optical system is usually adjusted to the same focus. ing. Therefore, in the conventional image reading apparatus, since the upper surface of the contact glass is located in the same plane, the optical system for reading the original in the first reading mode is more complicated than for reading the original in the second reading mode. Is out of focus and the original cannot be read satisfactorily.

Accordingly, the present invention provides a first reading position and a second reading position.
Even when reading a document on any contact glass at the reading position, it is possible to prevent the optical system from being out of focus,
It is an object of the present invention to provide an image reading apparatus with high reading performance that can read a document satisfactorily.

[0007]

According to the first aspect of the present invention,
In order to solve the above-mentioned problems, a first reading mode in which a document is read by an optical system stopped below a first reading position while the document is being conveyed, and the document is placed on a second reading position and the second reading position is set. A second reading mode for reading a document by moving the optical system downward, wherein the upper surface of the contact glass provided at the first position is set to the upper surface of the contact glass provided at the second reading position. It is characterized by being lower than that.

In this case, when the original is read on the contact glass at the first reading position, the upper surface of the contact glass provided at the second reading position is aligned with the conveying surface of the original conveyed onto the first reading position. Can be adjusted to the focus of the optical system when reading an original on the contact glass at the second reading position. As a result, when the original is read on the contact glass at the first reading position and the second reading position, the focus of the optical system is the same, the original can be read well, and the reading performance of the original can be improved.

According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect of the present invention, the contact glass is provided so as to face an upper surface of the contact glass provided at the first reading position. And a guide member forming a part of a document conveyance path, and a lower surface of the guide member facing the contact glass is flush with or slightly higher than an upper surface of the contact glass provided at the second reading position. It is characterized in that the guide member is arranged so as to be as follows.

In this case, by aligning the lower surface of the guide member provided opposite to the contact glass provided at the first reading position with the upper surface of the contact glass at the second reading position, the contact glass at the first reading position can be formed. Even when the document is transported above the contact glass when the document is transported between the guide members, the focus when reading the document on the contact glass at the first reading position is set to the second focus.
It is possible to reliably focus on the optical system when reading an original on the contact glass at the reading position.

Note that the case where the guide member is arranged such that the lower surface of the guide member facing the contact glass is slightly higher than the upper surface of the contact glass provided at the second reading position means that the contact glass of the first reading section When the optical system is focused on a white reference sheet or the like provided on the lower surface of the pressure plate that can be opened and closed above, when the original is placed on the contact glass, the optical system focuses by the thickness of the original. In this case, the guide member is arranged so that the lower surface thereof is slightly higher than the upper surface of the contact glass in consideration of the thickness of the document.

According to a third aspect of the present invention, in order to solve the above problem, in the first or second aspect of the invention, the contact glass provided at the first reading position and the second reading position is divided, The upper surface of the contact glass provided at the first reading position is treated with a material having a low friction coefficient, and the rear surface is treated with a conductive material.

In this case, when the document surface comes into contact with the surface of the contact glass, it is difficult for the ink and toner to be peeled off from the document surface, and it is possible to prevent the document from rubbing at the time of contact and to generate paper dust and the like. In addition, since static electricity generated by contact with the document is grounded to the main body frame of the image reading device and does not remain on the contact glass, floating dust such as paper dust and toner can be hardly attached.

As a result, it is possible to prevent dust from adhering to the contact glass, so that white streaks caused by the adhesion of white dust such as paper debris and black streaks caused by the adhesion of black dust such as ink and toner. Can be prevented from being read, and a good image can be continuously read. Further, since the contact glass provided at the second reading position is treated with a material having a low friction coefficient and a conductive material on the front and back surfaces of the divided contact glass, the processing area is reduced, and the production of the contact glass is reduced. An increase in cost can be prevented.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of an image reading apparatus according to the present invention. First, the configuration will be described. In FIG. 1, reference numeral 1 denotes an image reading device such as a copying machine, a facsimile device, a scanner device, and the like. A first contact glass (first reading position) 2 and a second contact A glass (second reading position) 3 is provided separately.

An exposure lamp 4 and a first mirror 5 are provided below the first contact glass 2 and the second contact glass 3, and the exposure lamp 4 and the first mirror 5 are provided.
When reading a document placed on the second contact glass 3, the user moves left and right in FIG. 1 below the second contact glass 3, and reads a document on the first contact glass 2. After stopping below the first contact glass 2 and reading the original surface by the exposure lamp 4, the reflected light is transmitted through a first mirror 5 and an optical system such as a lens (not shown) to a CCD or the like in a known manner. The image is formed on an imaging element or a photosensitive drum.

An ADF 6 is provided above the image reading apparatus 1.
The ADF 6 is connected to the image reading apparatus 1 via a hinge (not shown) and can be opened and closed with respect to the image reading apparatus 1. On the lower surface of the ADF 6, an original P1 placed on the second contact glass 3 is pressed against the second contact glass 3, and on the lower surface, a white sheet 7a and a white sheet 7 serving as a white reference when reading the original.
pressure plate 8 having cushioning material 7b provided on the upper surface
Is provided.

A document table 9 is provided above the ADF 6, and a document bundle P composed of a plurality of documents is placed on the document table 9 with the document surface facing upward. I have. The document bundle P placed on the document table 9
Is composed of a separation roller 11 and a reverse roller 12 which are movably provided at positions indicated by solid lines and broken lines, are fed by a calling roller 10 which can be brought into contact with and separated from the document bundle P, and then rotate clockwise together. The uppermost document is separated by the separation roller pair.

The conveyor roller pair 13 is rotated at a conveying speed (rotational speed) V1 separated by the separating roller pair, and is conveyed onto the first contact glass 2 by the conveying roller pair 13, and stops below the first contact glass 2. After the original surface is read by the exposure lamp 4 or the like,
Transport speed (rotational speed) V
The paper is discharged onto the pressure plate 8 by a paper discharge roller pair 15 rotating in 2.

The first contact glass 2 is a holding member.
It is fixed to the main body frame 1a by 16 and a white guide (guide member) 17 is opposed to the upper surface. The white guide 17 constitutes a white reference when reading the original, and also constitutes a part of the original transport path between the first contact glass 2 and a curved guide for securing the reverse path of the original. You are.

The upper surface 2a of the first contact glass 2
Is treated with a material having a low coefficient of friction such as silicon or fluorine, the back surface 2b is treated with a conductive material such as indium, and grounded to the main body frame 1a by indium. On the other hand, the first mirror 5 is used to set the focal length of the optical system.
Is located below the upper surface of the first mirror 5 by H.
Maintains the distance of H while contact glass 2,
3 is moved below.

The white guide 17 is arranged so that its lower surface is located on substantially the same plane A as the upper surface of the second contact glass 3.
It is provided on the lower surface by Δy (about 0.5 mm) with respect to
The upper surface 2a of the contact glass 2 is disposed below the upper surface (document placement surface) of the first contact glass 2.

In the present embodiment, the relationship between the transport speed V1 of the transport roller pair 13 and the transport speed V2 of the discharge roller pair 15 is V1
<V2 = V1 × 1.01, and the transport speed V2 of the paper discharge roller pair 15 is set to be 1% faster than the transport speed V1 of the transport roller pair 13. The reason why the document is marked with is to indicate the procedure of feeding and discharging the document. Next, the operation will be described.

First, when reading a document in the second reading mode, after the pressure plate 8 is opened, the document is placed on the second contact glass 3 and then the pressure plate 8 is closed to move the document P1 to the second position.
The contact glass 3 is pressed. In this state, when the start switch provided on the image reading device 1 is pressed, the exposure lamp 4 and the first mirror 5 move below the second contact glass 3 in the left-right direction in FIG.

On the other hand, a method of reading a document in the first reading mode will be described with reference to FIG. When the original bundle P is placed on the original placing table 9 with the original surface facing downward and the start switch is pressed, the call roller 10 moves to the position shown by the broken line, and comes into contact with the original bundle P and rotates. Feed P. After the uppermost document Pn is separated by the separation roller pair including the separation roller 11 and the reverse roller 12, the separated document Pn is moved toward the first contact glass 2 by the transport roller pair 13. Conveyed.

When the original Pn is conveyed onto the second contact glass 2, the leading end of the original Pn comes into contact with the second contact glass 2 as shown in FIG. Touch At this point, the reading of the document Pn is started with the exposure lamp 4 and the first mirror 5 stopped below the first contact glass 2. Next, when the document Pn is picked up by the paper discharge guide 14, as shown in FIG. 2B, the document Pn is curved by the thickness t of the document Pn itself, rises from the second contact glass 2, and rises from the second contact glass 2. Contact with

Next, the leading end of the document Pn is set to the discharge roller pair 15.
2C, the transport speed V2 of the discharge roller pair 15 is set to be 1% faster than the transport speed V1 of the transport roller pair 13, and as shown in FIG. The sheet is lifted from the second contact glass 2 and is conveyed while being in contact with the white guide 17, and is discharged onto the pressure plate 8 by the discharge roller pair 15 after reading is completed.

As described above, in the present embodiment, the upper surface 2a of the first contact glass 2 is lower than the upper surface of the second contact glass 3, and is conveyed onto the first contact glass 2 on the upper surface 2a of the second contact glass 3. Since the transport surface of the original Pn is adjusted, the focus of the optical system when reading the original Pn on the first contact glass 2 is adjusted to the focus of the optical system when reading the original Pn on the second contact glass 3. Can be.

As a result, when the original Pn is read on the first contact glass 2 and the second contact glass 3, the focus of the optical system is the same, and the original Pn can be read well, and the reading performance of the original Pn can be improved. Can be enhanced.
In particular, in the present embodiment, the white guide 17 is arranged so that the lower surface of the white guide 17 facing the upper surface 2a of the first contact glass 2 is at the same height as the upper surface of the second contact glass 3. When the document Pn is conveyed above the first contact glass 2 when the document Pn is conveyed between the second contact 2 and the white guide 17, the focus when reading the document Pn on the first contact glass 2 is set to the second position. The focus can be reliably adjusted to the focus of the optical system when reading the document Pn on the contact glass 3.

Further, the first contact glass 2 and the second contact glass 3 are divided, the upper surface 2a of the first contact glass 2 is treated with a material having a low coefficient of friction such as silicon or fluorine, and the back surface 2b is formed of indium or the like. When the original Pn surface comes into contact with the upper surface 2a of the first contact glass 2, ink, toner, and the like can be hardly peeled off from the original Pn surface when the original Pn surface comes into contact with the upper surface 2a. Generation of paper dust and the like can be suppressed. In addition, since static electricity generated by contact with the document Pn is grounded to the main body frame 1a and can be prevented from remaining on the first contact glass 2, floating dust such as paper dust and toner can be hardly attached. .

As a result, since dust can be prevented from adhering to the first contact glass 2, white streaks such as paper dust and black streaks such as ink and toner adhere to the first contact glass 2. It is possible to prevent an abnormal image such as a black stripe from being read, and it is possible to continuously read a good image. In addition, the first contact glass 2 divided with respect to the second contact glass 3
Since the above-mentioned processing is performed on the front and back surfaces of the first contact glass 2, it is possible to reduce the processing area and prevent the manufacturing cost of the first contact glass 2 from increasing.

In the present embodiment, the white guide 17 is arranged so that the lower surface of the white guide 17 facing the first contact glass 2 is flush with the upper surface of the second contact glass 3. Alternatively, the white guide 17 may be arranged so that the lower surface of the white guide 17 is slightly higher than the upper surface of the second contact glass 3. This is done in the second
When the optical system is focused on a white sheet 7a provided on the lower surface of a pressure plate 8 which can be opened and closed on the contact glass 3, when the original P1 is placed on the second contact glass 3, This is because the focus of the optical system is adjusted by the thickness (that is, the focal length is H + the thickness t of the document with respect to H described above).

[0033]

According to the first aspect of the present invention, the upper surface of the contact glass provided at the second reading position is aligned with the conveying surface of the document conveyed to the first reading position.
The focus when reading the document on the contact glass at the first reading position can be adjusted to the focus of the optical system when reading the document on the contact glass at the second reading position.

As a result, when the original is read on the contact glass at the first reading position and the second reading position, the focus of the optical system is the same, and the original can be read well.
Original reading performance can be improved. According to the invention described in claim 2, the upper surface of the contact glass at the second reading position is aligned with the lower surface of the guide member provided opposite to the contact glass provided at the first reading position,
When reading an original on the contact glass at the first reading position, even when the original is transported above the contact glass when the original is transported between the contact glass at the first reading position and the guide member. Can be reliably adjusted to the focus of the optical system when reading an original on the contact glass at the second reading position.

According to the third aspect of the present invention, it is possible to make it difficult for ink or toner to peel off from the original surface when the original surface comes into contact with the surface of the contact glass, and also to cause the original to rub at the time of contact and to remove paper dust or the like. Can be suppressed. In addition, since static electricity generated by contact with the document is grounded to the main body frame of the image reading device and does not remain on the contact glass, floating dust such as paper dust and toner can be hardly attached.

As a result, it is possible to prevent dust from adhering to the contact glass, so that white streaks caused by the adhesion of white dust such as paper debris and black streaks caused by the adhesion of black dust such as ink and toner. Can be prevented from being read, and a good image can be continuously read. Further, since the contact glass provided at the second reading position is treated with a material having a low friction coefficient and a conductive material on the front and back surfaces of the divided contact glass, the processing area is reduced, and the production of the contact glass is reduced. An increase in cost can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an image reading apparatus according to the present invention.

FIG. 2 is a diagram illustrating a document conveying procedure in a first reading mode according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 1st contact glass (1st reading position) 3 2nd contact glass (2nd reading position) 17 White guide (guide member)

Claims (3)

[Claims] A first reading mode in which the original is read by an optical system stopped below the first reading position while the original is being conveyed; and a document is placed on the second reading position and optically read below the second reading position. A second reading mode for reading an original by moving the system, wherein the upper surface of the contact glass provided at the first position is lower than the upper surface of the contact glass provided at the second reading position. An image reading apparatus, comprising: A guide member that is provided opposite to an upper surface of the contact glass provided at the first reading position and forms a part of a document conveyance path together with the contact glass; 2. The image reading apparatus according to claim 1, wherein the guide member is arranged such that a lower surface of the guide member is flush with or slightly higher than an upper surface of the contact glass provided at the second reading position. . 3. The contact glass provided at the first reading position and the second reading position is divided, and the upper surface of the contact glass provided at the first reading position is treated with a material having a low friction coefficient. 3. The image reading device according to claim 1, wherein the back surface is treated with a conductive material.