JPH04180342A - Original document picture reader - Google Patents

Abstract

PURPOSE:To realize the miniaturization, the reduction of the weight, and the reduction of the cost of an original document picture reader by arranging the reading part of a line sensor on an original paper feeding side to be out of the nip of an original carrying roller, and providing the reading part with an original contacting means. CONSTITUTION:An original contacting member 3 is arranged on the original paper feeding side 13 of a point at which the line sensor 1 and the carrying roller 2 are brought into contact with each other, and on the outside of the collapsed width of the carrying roller 2. Distance between the original contacting member 3 and the carrying roller 2 on the line sensor 1 is determined so that the original contacting member 3 arranged in a reading position 4 and the carrying roller 2 do not interfere with each other. Besides, generally speaking, since there is possibility that the carrying force of the automatic paper feeding part 13 becomes unstable according to the variation of the paper quality of the original, the distance between the original contacting member 3 and the carrying roller 2 is preferably short, and 2 to 5mm is the distance not to cause trouble actually. Since the carrying roller 2 bears a function only to carry the original, the rubber part of the carrying roller 2 can be made short. Thus, the influence of the flatness of the reading surface of the line sensor can be reduced, and the original can stably be carried.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a document image reading device, and more specifically, it is applied to an image information processing device such as a facsimile machine or an image scanner, which optically reads image information of a document. The present invention relates to a document image reading device.

[Background Art] In recent years, there has been an increasing demand for image information processing devices such as facsimiles and image scanners to be smaller, lighter, and lower in price. Particularly in the field of facsimiles, as the market for home facsimiles for personal use has expanded, demands have increased not only for smaller size, lighter weight, and lower prices, but also for a wide variety of designs and functions.

The document image reading device that is installed in such an image information processing device and optically reads the image information of the document is a reduction reading method that combines a line sensor such as a CCD and a reduction optical system, and the length is the same as the width of the document. A close-contact reading method that integrates a line sensor with a lens array, a same-magnification optical system such as a focusing fiber lens array, and a light source such as an LED array in a frame, or a line sensor and a light source that do not use a lens array. A document image reading device such as a complete contact type reading method is employed, in which the document is integrated into a frame and the document is brought close to a line sensor to read the document image.

The schematic configuration of a conventional document image reading device is shown in Figures 1O and 1.
Shown in Figure 1. FIG. 1O is a sectional view schematically showing a conventional document image reading device, and FIG. 11 is a schematic perspective view of FIG. 10.

Here, l is a creeping sensor that optically reads the image of the document P. Reference numeral 13 denotes an automatic paper feeding unit consisting of a combination of a separation piece 11 and a binding roller 12, which separates and combines the originals P one by one toward the line sensor l. 2 is a conveyance roller, which transports the fed document P to the reading position 4 of the line sensor 1.
It has the function of a document conveying means for conveying the document P as well as a document adhering means for pressing the document P into close contact with the document P.

[Problem to be Solved by the Invention J] However, in the conventional document image reading device, since the document conveying means and the document contacting means are carried out on the conveying roller, there are the following problems.

(1) In order to read the original image with the line sensor, it is necessary to bring the line sensor and the original into close contact.
The length of the conveyance roller is required to cover the length of the line sensor or the entire reading width of the document. Therefore, due to the influence of the flatness of the reading surface of the line sensor, the conveying force varies depending on the position, causing skewing of the document.

(2) Place the original in close contact with the line sensor reading surface.

When conveying, the load applied to the motor that rotates the conveyance roller increases, which makes the motor more likely to generate heat, lose synchronization, and the like. Therefore, for stable document transport,
This requires the use of a large motor, making it difficult to reduce the size and weight of the document image reading device.

(3) Documents fed at an angle are more likely to become skewed.

This explanation will be made with reference to FIG.

FIG. 37 is a schematic plan view of the conventional document image reading device shown in FIGS. 1O and 11, viewed from above. Note that although not shown, the line sensor is arranged on the back side of the paper surface of the document transport roller 2.

In FIG. 7(A), when the document P is inserted diagonally into the automatic paper feeding section 13, the automatic paper feeding section 13 will be moved as shown in FIG. 7(B).
Accordingly, the document P is conveyed to the conveyance roller 2 by the conveyance force (a).

Next, in FIG. 7(C), a part of the document P sandwiched between the transport roller 2 and the line sensor is moved by the transport force of the transport roller 2 (
b) comes into play. Generally, the paper feed roller (not shown) of the automatic paper feed section 13 has a peripheral speed slightly lower than that of the conveyance roller 2. Therefore, due to the circumferential speed difference and the friction piece load, a load LC) acts in the opposite direction to the document conveyance direction, and (b)
A rotational force (d) is generated by the forces of and (C), and the original P is further skewed.

As with these problems, it cannot be said that the conventional structure is sufficient for the miniaturization, weight reduction, and cost reduction of document image reading devices, which have become increasingly popular in recent years. There are many.

[Means for Solving the Problems (and Effects)] According to the document image reading device of the present invention, the document is brought into close contact with the line sensor, the document is illuminated by a light source, and the reflected light on the document is detected by the line sensor. In a document image reading device that reads an image of a document using a document, the reading section of the line sensor is placed on the document feeding side so as to be outside the nip of the document transport roller, and the document adhesion means is provided in the reading section. The present invention solves technical problems and realizes miniaturization, weight reduction, and cost reduction of a document image reading device.

[Example] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic sectional view showing a first embodiment of a document image reading device according to the present invention, and FIG. 2 is a schematic perspective view of the document image reading device shown in FIG.

In FIGS. 1 and 2, 1 is a line sensor that reads the image of the document P, 2 is a conveyance roller that conveys the document P, and 3 is a document contact member that brings the document P into close contact with the reading position 4 of the line sensor I. be. Reference numeral 13 denotes an automatic paper feeding section consisting of a combination of a separating piece 11 and a feeding roller 12. The document adhering member 3 is disposed on the side of the document feeder 13 from a point 5 where the line sensor 1 and the conveyance roller 2 abut, and outside the collapsed width of the conveyance roller 2 . The distance between the document adhering member 3 and the conveying roller 2 on the line sensor l is determined so that the document adhering member 3 disposed at the reading position 4 and the conveying roller 2 do not interfere with each other. Incidentally, since the conveyance force of the automatic paper feeder i3 may become unstable due to changes in the paper quality of the document, it is desirable that the distance between the document contact member 3 and the conveyance roller 2 be as short as possible. A distance of 2 to 5 mm is a distance that does not pose a problem in practice.

Conveyance roller 2 is made of EPDM (ethylene propylene rubber)
, CR (chloroprene rubber), silicone, and other materials. The original adhesion member 3 is made of PE (polyethylene),
PET (polyethylene terephthalate)), PEEK
(polyetheretherketone), nylon, plastic films such as fluorine film, metal foil, aluminum foil,
Made of flexible material such as titanium foil. The thickness of the document adhesion member 3 is preferably 0.1 mm or less, and one end of the flexible member 3 is fixed to the support member 6 with an adhesive screw or the like.
The other end is brought into contact with the reading position 4 of the line sensor 1 by its own weight or by the springiness of the flexible member itself, and the line sensor 1
According to an embodiment of the invention, contacting the reading position of
It has the following effects.

(1) Since the transport roller 2 only has the function of transporting documents,
The rubber portion of the conveyance roller 2 can be shortened. As a result, the influence of the flatness of the reading surface of the line sensor can be reduced, making it possible to carry out stable document conveyance. Furthermore, since the flatness management of the reading surface of the line sensor, which was conventionally required, can be reduced, the cost can be easily reduced.

(2) Because the document transport function and document adhesion function are separated by separate members, the pressing force required to transport the document and the pressing force necessary to press the document onto the line sensor are different. can be minimized. In other words, the conventional force required to crush the conveying roller 2 and absorb the flatness of the line sensor is no longer necessary.

This reduces the load on the motor, making it possible to reduce the external dimensions and cost of the motor.

(3) Even when paper is fed diagonally, it is less likely to be skewed.

FIGS. 6(A) to 6(C) are schematic diagrams of an embodiment of the present invention viewed from above. Note that the line sensor is arranged on the back side of the paper surface of the document transport roller 2, although it is not shown. When the document P is inserted obliquely in FIG. 6(A), its leading edge collides with the document adhering means 3, which does not have the document conveyance force, as shown in FIG. 6(B), and load resistance (e) is generated. do.

In addition, since the paper feeding force (a) is working in the automatic paper feeding section 13, a rotational force (d) that corrects the original P is generated in combination with the load resistance (e), and the original P returns to the normal position. . When the load resistance (e) is distributed over the entire leading edge of the document,
The paper feeding force (a) overcomes the load resistance (e) and feeds the original to the original transport roller 2. In FIG. 6(C), the automatic paper feeder 1
Since almost no rotational force acts between the load (C) of No. 3 and the conveyance force (b) of the conveyance roller 2, the document can be conveyed without skew. At this time, by aligning the center of the rubber portion of the conveyance roller 2 in the main scanning direction, the center of the automatic paper feeder 13, and the center of the effective reading length of a line sensor (not shown), the document can be conveyed even more easily. can be done.

(4) By making at least a part of the reading position of the document contacting means 3 white, the image is not affected even when reading thin paper, transparent documents, or narrow documents. Furthermore, it can also be used as a white reference during multi-tone reading. In other words, it is possible to electrically correct the output of the line sensor 1 by storing it in bits, for example, using the reflectance of the white portion of the document contacting means 3 as a reference. As means for making it white, the document pressing means 3 itself may be white, or the surface of the document pressing means 3 on the document side may be provided with white painting, printing, etc. Alternatively, the same effect can be obtained by painting, printing, etc. on the surface of the transparent document pressing means 3 opposite to the document surface.

FIG. 3 is a schematic cross-sectional view showing a second embodiment of the document image reading device according to the present invention. In FIG. 3, the document adhesion means is composed of an elastic member 3 and a pressing spring 7. As the elastic member 3, a material such as rubber or sponge, or a member having elasticity in shape is used. Although the pressing spring 7 is used as an example of the pressing means, good effects can also be obtained by using gravity.

FIG. 4 is a schematic cross-sectional view showing a third embodiment of the document image reading device according to the present invention. FIG. 4 shows an embodiment in which the document conveyance roller 2 is provided outside the line sensor 1. The backup roller 8 is pressed by the document conveyance roller 2 and pinches and conveys the document P in a manner that follows the document conveyance roller 2. Also, the document pressing means is configured to press the flexible member 3 as shown in FIG. I am using it.

FIG. 5 is a schematic cross-sectional view showing a fourth embodiment of the document image reading device according to the present invention. In Figure 5, the first
A member (hereinafter referred to as a sliding member) 10 having a friction coefficient smaller than the friction coefficient between the reading surface of the line sensor 1 and the transport roller 2 is disposed at the contact point 5 of the document transport roller 2 in the illustrated embodiment. Usually, the reading surface of the line sensor I is made of glass, and the sliding member 10 is made of fluororesin or the like. The sliding member 10 is a line sensor 1
It may be provided on the reading surface by printing, painting, pasting, etc., or it may be provided on the casing of the line sensor 1, for example, outside the easy-to-read area that does not interfere with paper passing. As a result, even when the document P is not at the contact point 5 of the transport roller 2, it is possible to rotate the transport roller 2 with a light load.
This is effective for downsizing motors and reducing power consumption.

FIGS. 8 and 9 show an example in which the original image reading apparatus of FIG. 1 is integrally constructed within a frame to form a unit, as a fifth embodiment of the original image reading apparatus according to the present invention. be. Note that the separation piece 11 is supported by an unillustrated member,
It is locked to the frame 9. The frame 9 has a structure that integrally supports the line sensor 1, the separation piece 11, the paper feed roller 12, the document transport roller 2, and the document adhesion means 3.

[Effects of the Invention] As explained above, the document image reading device of the present invention provides
The conventional problems of skew, high cost, and large external dimensions of motors, etc., have been solved, and it has become possible to reduce the size, weight, and price that have been desired in recent years. Furthermore, the following advantages can be obtained by integrally arranging the embodiment of the present invention on a frame and forming a unit.

(1) The accuracy of assembling parts related to document reading is improved.

(2) By standardizing this unit and incorporating it into all types of image information processing devices, the burden of design, evaluation, and production can be greatly reduced, and the total cost of one image information processing device can be reduced. I can do it.

(3) Since the document image reading device is a small and lightweight unit, the layout inside the image information processing device is easy, and the degree of freedom in design is improved.

(4) When the document reading device in the image information processing device becomes defective or breaks down, it can be repaired by simply replacing the unit, so there is no need for special training, skills, or tools (and the user can easily repair it himself). be able to.

In addition, according to the present invention, an inexpensive and compact original image reading device is possible, and can be applied to various image information processing devices such as facsimiles, image sensors, computers, word processors, and copying machines.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a first embodiment of a document image reading device according to the present invention, and FIG. 2 is a perspective view schematically showing a first embodiment of a document image reading device according to the present invention. 3 is a sectional view schematically showing a second embodiment of the document image reading device according to the present invention, and FIG. 4 is a sectional view schematically showing a third embodiment of the document image reading device according to the present invention. FIG. 5 is a cross-sectional view schematically showing a fourth embodiment of the document image reading device according to the present invention. FIG. 6 is a diagram illustrating the state of document conveyance in the document image reading device according to the present invention. FIG. 7 is a diagram explaining the state of document conveyance in the conventional document image reading device. FIG. FIG. 9 is a sectional view schematically showing a fifth embodiment of the document image reading device according to the present invention; FIG. FIG. 11 is a cross-sectional view schematically showing a conventional document image reading device. FIG. 11 is a perspective view schematically showing a conventional document image reading device. l...Line sensor. 2... Document conveyance roller, 3... Document adhesion means, 4... Reading position, 5... Contact position of document conveyance roller, 6... Support member, 7... Pressing spring, 8 ...Backup roller, 9...Frame, IO...Sliding member, 11...Separation piece, 12...Paper feed roller, 13...Automatic paper feed section, P...Document, ( a) ...Document conveying force of the automatic paper feeder, (b)
...Document transport force of the transport roller, (c) ...Load on automatic paper feed section, (d) ...Rotational force, (e) ...Load.

Claims (9)

[Claims] (1) In a document image reading device that brings a document into close contact with a line sensor, illuminates the document with a light source, and reads an image of the document by detecting light reflected by the document with the line sensor, the line sensor reads the document. What is claimed is: 1. A document image reading device, characterized in that a document image reading device is arranged on a document feeding side so as to be outside a nip of a document conveyance roller, and a document adhering means is provided in the reading device. (2) The document image reading device according to claim 1, wherein the document contacting means is a film-like flexible member. (3) Claim 1, wherein the document contacting means is made of an elastic member that is elastically pressed against the line sensor.
The document image reading device described in . (4) The document image reading device according to claim 1, wherein the document conveyance roller is in contact with a reading surface of the line sensor. (5) The document image reading device according to claim 4, wherein the automatic paper feeder, the reading position, and the conveyance roller are arranged in this order from the paper feed side to the paper discharge side in the document conveyance direction. (6) A straight line connecting the center position of the paper feed roller of the automatic paper feed means in the direction perpendicular to the document transport direction and the center position of the document transport roller in the direction perpendicular to the document transport direction is the line sensor. 6. The document image reading device according to claim 5, wherein the document image reading device passes through the center of the effective reading length in the main scanning direction. (7) The document image reading device according to claim 1, wherein at least a portion of the document contacting means is white. (8) Document image reading according to claim 4, characterized in that a sliding member having a friction coefficient smaller than a friction coefficient between the reading surface and the document conveyance roller is disposed at a position where the document conveyance roller abuts. Device. (9) According to any one of claims 1 to 8, at least the automatic paper feeding means, the line sensor, the document conveying roller, and the document contacting means are integrally arranged in a frame to form a unit. original image reading device.