JP2000201260A - Picture reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent original floating phenomenon in a reading position on a sheet through original platen at the time of using a document feeder with inexpensive constitution. SOLUTION: Mylar 50 as a transportation limit member installed on the up stream side of a reading position Y in contact glass for sheet through 46 can freely be attached/detached, and it is exchanged to Mylar 50 in thickness corresponding to the paper thickness of an original 58. Since the transportation limit member is changed in accordance with the paper type of the original, picture deterioration owing to original floating can be prevented with inexpensive constitution.

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, a scanner, and the like. It relates to a reading device.

[0002]

2. Description of the Related Art In this type of image reading apparatus, a contact glass as a document table for sheet through is provided separately from a contact glass as a document table for fixing and reading a document. Sometimes, a scanning unit that scans a document placed on the contact glass while traveling in the sub-scanning direction is fixed at a reading position of the sheet-through contact glass, and the document is read while being transported on the sheet-through contact glass. Has been done. The read original is discharged onto a discharge tray of the DF. To reduce the size of the device, D
The transport path of F is configured to reverse the original.

For this reason, the original does not adhere to the glass surface at the reading position of the sheet-through contact glass, that is, the so-called floating of the original is likely to occur, and when the floating of the original occurs, the reading accuracy is reduced and image deterioration is caused. To cope with this problem, Japanese Patent Application Laid-Open No. Hei 10-186535 discloses a technique in which a sheet-through contact glass is constantly biased so as to be in close contact with a feed roller. According to this configuration, since the document is sandwiched between the feed roller and the sheet-through contact glass by the urging force, the document is securely brought into close contact with the sheet-through contact glass, and the document floating can be prevented. However, there is a problem that the provision of the biasing mechanism causes an increase in manufacturing cost.

As a low-cost method, a conveyance regulating member for guiding a document conveyed by a DF feed roller upstream of the reading position of the sheet-through contact glass so as to contact the reading position of the sheet-through contact glass. Is known. Mylar is used as a transfer regulating member.

[0005] An example of a simple configuration using a transport regulating member will be described with reference to FIG. A sheet-through contact glass 102 is positioned and provided so as to face the DF feed roller 100. The scanning unit 10 corresponds to the reading position Y of the sheet-through contact glass 102.
4 is fixed in position. Upstream of the reading position Y,
A mylar 106 as a transfer regulating member is provided with one end fixed. The mylar 106 is formed in a letter shape, and the document 110 nipped and conveyed by the feed roller 100 and the driven roller 108 is regulated by the free end of the mylar 106 and closely adheres to the sheet-through contact glass 102 at the reading position Y. You will be guided as follows. In FIG. 9, reference numeral 112 denotes a contact glass for fixing and reading an original, and reference numeral 114 denotes an upper guide plate.

[0006]

However, in the above-mentioned conventional technique, since the same mylar 106 is used regardless of the type of the document 110, for example, as shown in FIG. Is mylar 106
Is slightly lowered due to the weight of the original 110, whereby the original 110 is moved from the upstream side of the reading position Y to the sheet-through contact glass 102 as indicated by a broken line.
When the document is read normally by touching the
If the paper is thin, the original 11
0 loses the waist strength, so the free end of the mylar 106 hardly goes down.
Reference numeral 10 contacts the sheet-through contact glass 102 for the first time on the downstream side of the reading position Y. At the reading position Y, a gap g is formed and the document floats.

When the document floats, a change in density due to a change in illuminance from the illumination lamp of the scanning means 104, or a problem in that, if the document has an oblique line, the oblique line is distorted and read. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus which can solve the problem of document floating with an inexpensive configuration.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a document feeder for transporting a document, a document table for fixing and reading the document, and a document scanning direction. Scanning means for traveling and scanning to
A document table for sheet-through provided separately from the document table, and a conveyance regulating member provided upstream of the reading position of the document table for sheet-through and guiding the document conveyed by the document feeder to the reading position. In the image reading apparatus fixed at a position corresponding to the sheet-through platen when the document feeder is used, the scanning unit changes the conveyance regulating member according to the type of the document. I am taking it.

According to a second aspect of the present invention, in the configuration of the first aspect, the thickness of the conveyance regulating member is changed according to the thickness of the document.

According to a third aspect of the present invention, in the configuration of the first aspect, a plurality of the transport restricting members are provided at intervals in a width direction substantially orthogonal to the transport direction of the original, and are provided in accordance with the thickness of the original. , The number of the transport regulating members is changed.

According to a fourth aspect of the present invention, in the configuration of the first aspect, the mounting position of the transport regulating member is changed in accordance with the thickness of the document.

[0013] According to the fifth aspect of the present invention, the first, second, and third aspects are provided.
The configuration according to 3 or 4, wherein the attachment and detachment of the transport regulating member is performed by a planar fastener.

According to the sixth aspect of the present invention, the first, second, and third aspects of the present invention are provided.
In the configuration described in 3, 4, or 5, a configuration is adopted in which the transport regulating member is a mylar.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a scanner 2 as an image reading apparatus according to the present embodiment includes a reading unit 4 and a DF (rotatably provided in a vertical direction with respect to the reading unit 4 via a hinge unit 6). (Automatic document feeder) 8.
The reading unit 4 includes a first carriage 14 equipped with an illumination lamp 10 and a first mirror 12, a second mirror 16 and a third
A second carriage 20 equipped with a mirror 18 and the like is provided so as to be able to reciprocate in the sub-scanning direction, and these mainly constitute a scanning unit.

On the upper surface of the reading section 4, there is provided a contact glass 22 as a document table for fixing and reading a document. When a document is placed and fixed on the contact glass 22 for reading, the first carriage 14 moves forward at a constant speed, and the second carriage 20 moves the first carriage 14 at half the speed of the first carriage 14. The document on the contact glass 22 is optically scanned by moving forward following the carriage 14. The original is illuminated by an illumination lamp 10 and its reflected light image is reflected by a first mirror 12, a second mirror 16,
An image is formed on the CCD sensor 26 by the lens 24 via the third mirror 18.

The CCD sensor 26 photoelectrically converts the formed reflected light image of the original and outputs an analog image signal. The analog signal is converted into a digital image signal by an analog / digital converter. Various image processing (binarization, gradation processing, scaling, and editing) are performed, and the original is read. After the image reading is completed, the first carriage 14 and the second carriage 20 return to the home position. The position shown in FIG. 1 is between the first carriage 14 and the second carriage 14.
The carriage 20 is at the home position.

Next, the configuration of the DF8 and the reading operation when the DF8 is used will be described. Documents stacked on the document tray 30 are sent to a separation unit by a pickup roller 32, where the feed roller 34 and the separation roller 3 are separated.
The sheets are separated and transported one by one. Thereafter, the document is transported by a transport drum 38 as a feed roller and a plurality of driven rollers 40 arranged around the transport drum 38 and pressed by the transport drum 38.

When the conveyed document reaches the reading position (the home position) Y, the lower surface of the document is illuminated by the illumination lamp 10 at a predetermined timing, and the reflected light is reflected by the first mirror 12 and the second mirror. 16. An image is formed on the CCD sensor 26 by the third mirror 18 in the same manner as in the above operation, and is photoelectrically converted. The operation after the analog signal output by the CCD sensor 26 is the same as the above operation. The original is transported to the right side in FIG. 1 by the transport drum 38 and the driven roller 40, and the reflected light entering the CCD sensor 26 is scanned in the sub-scanning direction of the original. The document from which the image information has been read is discharged onto a discharge tray 44 by a discharge roller pair 42.

Next, the configuration around the reading position Y in this embodiment will be described in detail. As shown in FIG. 2, a sheet-through contact glass 46 is provided at the reading position Y so as to face the transport drum 38, and an upper guide plate 47 is provided above the sheet-through contact glass 40. . Contact glass 46 for sheet through
The driven roller 40 in the vicinity thereof is held by a support plate 48. As shown in FIG. 3, the support plate 48 is a molded part integrally formed. On the support plate 48, four driven rollers 40 are rotatably supported at intervals in a width direction (main scanning direction) substantially orthogonal to the document conveying direction. A mylar 50 as a transport regulating member is detachably attached to the bottom surface 48a.

The mylar 50 includes a mounting portion 50a and a regulating portion 50b extending obliquely downward from the mounting portion 50a. As shown in FIG. 4, a planar fastener 52 is fixed to the lower surface of the mounting portion 50a. I have. Correspondingly, the flat bottom surface 48a of the supporting recess of each driven roller 40 has
As shown in FIG. 7, the planar fastener 54 is fixed.
As shown in FIG. 5, the planar fastener 52 of the mylar 50 is provided.
The mylar 50 can be easily attached to the support plate 48 by connecting the mylar 50 with the planar fastener 54 of the bottom surface 48a. The planar fastener 54 on the bottom surface 48a side is a mylar 50
Are formed longer in the sub-scanning direction (the direction of arrow S) than the planar fasteners 52, so that the projecting position of the mylar 50 in the sub-scanning direction can be adjusted. As shown in FIG. 3, fixing holes 48b are formed at both ends of the support plate 48, and are fixed at the positions shown in FIG. In FIG. 6, reference numeral 56 denotes a white plate.

Each mylar 50 is for thin paper and is formed thinner than conventional ones. For this reason, as shown in FIG.
The bent original 58 contacts the sheet-through contact glass 46 on the upstream side of the reading position Y so that the inclination angle β of 0 is smaller than the inclination angle α of the mylar 106 in the conventional configuration shown in FIG. For this reason, the document does not float. If the original is a thick paper, replace it with a Mylar having a thickness corresponding to the original. As described above, the one-touch attachment / detachment using the planar fastener allows easy and quick replacement. In this embodiment, the original is roughly classified into thin paper and thick paper, and the corresponding Mylar 50 is prepared. However, the paper thickness of the original is divided into several stages, and the corresponding Mylar 50 is prepared and exchanged. Then, the floating of the document can be prevented with high accuracy. Further, the Mylar 50 for thin paper and the Mylar 50 for thick paper may be mixed so as to be able to cope with various paper thicknesses of the document.

In the above-described embodiment, the configuration is adopted in which the thickness of the mylar 50 is changed to cope with the change in the paper thickness of the original. However, the number of mylars 50 is changed so as to cope with the change in the paper thickness of the original. You can also. For example, in FIG. 3, when the original is thin paper, only the mylar 50 corresponding to the positions A and D is used, or only the mylar 50 corresponding to the positions A and C is used. When the number of mylars 50 decreases, the strength of the mylar as a whole with respect to the document changes, so that it is possible to cope with a change in paper thickness. In the case of the present embodiment, the total strength of the mylar waist when all four mylars 50 are used may be set to correspond to the cardboard document. In this way, there is no need to facilitate a different mylar as compared with the above embodiment, and thus parts management is easy.

Next, another embodiment will be described with reference to FIGS. Note that the same parts as those in the above embodiments are denoted by the same reference numerals, and redundant description will be omitted. The present embodiment is characterized in that a thin paper document can be handled by using only Mylar 60 having a thickness corresponding to thick paper. The number of mylars 60 and the attachment / detachment configuration are the same as in the above embodiments. FIG. 7 shows the attachment position when the original is thick paper. As shown in FIG. 5, the planar fastener 52 of the mylar 60 is
The length is smaller than that of the planar fastener 54 provided on the flat bottom surface 48a of the support concave portion so that the mounting position in the sub-scanning direction (the direction of arrow S) can be changed. In the present embodiment, the adjustment of the attachment position corresponds to a change in the paper thickness of the document.

FIG. 7 shows a state in which the mylar 60 is protruded in the sub-scanning direction. At the mounting position corresponding to the thick paper, the thin paper original 58 loses the rigidity of the mylar 60.
Document floating occurs. However, as shown in FIG.
If the projecting amount of the Mylar 6 is reduced, the contact position between the free end of the Mylar 60 and the thin paper document 58 changes (L1
<L2) There is no problem even if the stiffness of the mylar 60 is large, and the document 58 comes into contact with the sheet-through contact glass 46 on the upstream side of the reading position Y, and no document float occurs.

In the present embodiment, since the fixing is performed by the planar fastener, the amount of protrusion of the mylar 60 can be finely adjusted, so that one type of mylar 60 can cope with various thicknesses of the original. Also in the present embodiment, a usage mode in which the protrusion amount of any one of the four mylars 60 is different from the others may be used.

In each of the above embodiments, the mylar serving as the conveyance restricting member is changed in accordance with the change in the thickness of the document. However, the same applies to the case where the mylar is changed in accordance with the paper quality (type) of the document. Can be implemented.

[0028]

According to the first aspect of the present invention, since the conveyance regulating member is changed in accordance with the type of the original document,
It is possible to prevent the image deterioration due to the floating of the document with an inexpensive configuration.

According to the second aspect of the present invention, the thickness of the conveyance regulating member is changed according to the thickness of the document.
It is possible to prevent the image deterioration due to the floating of the document with an inexpensive configuration.

According to the third aspect of the present invention, the number of the transport regulating members is changed according to the thickness of the document.
Two types of transport regulating members can be used, and component management becomes easy.

According to the fourth aspect of the present invention, since the mounting position of the transport restricting member is changed according to the thickness of the document, one type of transport restricting member can be used, and component management is facilitated. .

According to the fifth aspect of the present invention, since the attachment / detachment structure of the transfer restricting member is formed by a planar fastener, the attachment / detachment operation can be performed with one touch and is easy. Also,
Since the attachment position can be finely adjusted, it is possible to cope with various paper thicknesses of the original.

According to the sixth aspect of the present invention, since the transfer regulating member is formed by Mylar, it can be made inexpensive and easy to manufacture.

[Brief description of the drawings]

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

FIG. 2 is a schematic sectional view around a reading position when a DF is used.

FIG. 3 is a perspective view showing a mounting position of a mylar.

FIG. 4 is a perspective view of the mylar seen from the back side.

FIG. 5 is a cross-sectional view of a main part showing a method for mounting a mylar.

FIG. 6 is a perspective view illustrating a state in which a DF of the image reading apparatus is rotated upward.

FIG. 7 is a schematic cross-sectional view around a reading position when a DF is used in another embodiment.

FIG. 8 is a schematic cross-sectional view around the reading position in a state in which the mounting position of the mylar is changed in the embodiment shown in FIG. 7;

FIG. 9 is a schematic cross-sectional view of the vicinity of a reading position when a conventional DF is used.

[Explanation of symbols]

58 Document 8 Document feeder 22 Contact glass as a document table S Sub-scanning direction 46 Sheet-through contact glass as a sheet-through document table 50, 60 Mylar 52, 54 as a conveyance regulating member 52, 54 Sheet fastener

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Nobuhiro Shima 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Hiroyuki Watase 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Junichi Murano 1-3-6 Nakamagome, Ota-ku, Tokyo ・ Ricoh Co., Ltd. (72) Keisuke Igarashi 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 5C062 AA02 AA05 AB02 AB17 AB30 AB31 AB32 AD05 BA01 5C072 AA01 BA02 BA13 BA20 DA21 DA23 LA02 LA18 MB06 NA01 XA01

Claims (6)

[Claims] A document feeder for conveying a document;
A document table for fixing and reading the document, scanning means for traveling and scanning the document in the sub-scanning direction, a sheet through document table provided separately from the document table, and a sheet through document table A transport regulating member provided upstream of the reading position and for guiding the document conveyed by the document feeder to the reading position, wherein the scanning means corresponds to the sheet-through document table when the document feeder is used. An image reading device fixed in position, wherein the transport regulating member is provided detachably, and the transport regulating member is changed in accordance with a paper type of a document. 2. The image reading apparatus according to claim 1, wherein the thickness of the conveyance regulating member is changed according to the thickness of the document. 3. The image reading apparatus according to claim 1, wherein a plurality of said transport restricting members are provided at intervals in a width direction substantially orthogonal to a transport direction of the original, and said transport restricting member is provided in accordance with a thickness of the original. An image reading apparatus, wherein the number of members is changed. 4. The image reading apparatus according to claim 1, wherein the mounting position of the conveyance regulating member is changed according to the thickness of the document. 5. An image reading apparatus according to claim 1, wherein said transfer regulating member is attached and detached by a sheet fastener. 6. An image reading apparatus according to claim 1, wherein said transport regulating member is a mylar.