JPH0614160A - Image reading mechanism - Google Patents

Abstract

PURPOSE:To prevent the optical reading positions of even originals with various kinds of thickness from being fluctuated. CONSTITUTION:A reading mechanism in which an automatic paper feed mechanism 1 is provided and which performs the white reference decision of the original with a white sheet 5 is comprised in such a way that a tensile force is applied to the original between the contact plane of the original with a full width roller with stage for original carrying and the contact plane with a roller in the automatic paper feed mechanism 1 and the original can be prevented from floating over the reading position by employing such constitution that a floating prevention guide 8 for original is provided, and the movable guide 9 of the white sheet moving in an original floating direction is unified with the white sheet 5 located on the reading plane of a reading device 2 on which the original is adhered closely and a prevention spring 6 which prevents the white sheet from floating functions in a direction to negate a force in the original floating direction when it is applied to the movable guide 9 of the white sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading mechanism, and more particularly to an image reading mechanism used in a facsimile apparatus and similar apparatus for reading a current image.

[0002]

2. Description of the Related Art Conventionally, an image reading mechanism of this type is shown in FIG.
Shown in (a) and (b). The image reading mechanism of FIG. 2A has a paper guide 11 for guiding the traveling of a document, a document contact-type reading device 13 for reading the document, a function of pressing the document for conveyance, and a function of determining a white reference when reading the document. It also has a white roller 12 that also serves as a sheet, and an automatic paper feed mechanism 10 that conveys a plurality of documents one by one.

The image reading mechanism shown in FIG. 2B has a paper guide 18 for guiding the travel of a document, a document contact type reading device 17 for reading a document, a document conveying roller 14,
15 and a white sheet 1 having a function of determining the white reference and pressing the document when the reading device 17 reads the document.
6 and an automatic paper feed mechanism 19 for conveying a plurality of originals one by one.

[0004]

In this conventional image reading mechanism, in FIG. 2 (a), the width of the white roller is pressed against the reading device via the document, so that the load becomes large, and when the document is read. Since it also serves as the white reference determination, it is difficult to control the light reflectance of the white roller, and the cost is higher than that of a general roller. Also, since this white roller is a full width roller,
There is also a problem that the document is easily skewed when it is conveyed.

In FIG. 2 (b), since the original feeding roller is not a full width roller, the load on the roller is reduced, skewing does not easily occur during the original feeding, and the white reference judgment is performed on the white sheet, so the roller light Although there is an advantage that it is not necessary to manage the reflectance of the document, the white reference value changes because the white sheet for judging the white standard of this document cannot completely press this document against a wrinkled document. There was a problem.

[0006]

SUMMARY OF THE INVENTION An image reading mechanism of the present invention comprises a central stepped full-width roller for bringing a document into close contact with a document reading surface and a device for reading the image, and the device for reading the document. When a white sheet used for white reference determination at the time, an automatic paper feed mechanism that conveys a plurality of originals one by one, and an original fed by the automatic paper feed mechanism is conveyed by the full width roller, the original Is a floating prevention guide for preventing floating from the reading surface of the device,
A movement guide having a fulcrum on the opening / closing frame, which is integrated with the white sheet and moves along the floating direction of the document.
The floating prevention spring works in a direction that hinders the movement of the movement guide.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a front view (a) and a side view (b) of an embodiment of the present invention.

In this embodiment, an original contact type reading device 2 for reading an original, a paper guide 4 provided on the discharge side of the reading device 2, and a central stage for conveying originals arranged above the paper guide 4. A full width roller 3 attached thereto, a white sheet 5 for determining the white reference of the original on the reading surface of the reading device 2, an automatic paper feeding mechanism 1 for feeding out the original one by one,
A guide 8 for preventing the document from floating, a white sheet moving guide 9 which has a fulcrum on the closing / opening frame 7 and moves integrally with the white sheet 5 following the floating direction of the document, and a white sheet moving guide 9. The white sheet floating prevention spring 6 is provided with a force that acts in a direction that impedes movement.

Next, the operation of this embodiment will be described. When a plurality of originals are fed out one by one by the automatic paper feeding mechanism 1, pass through the original floating prevention guide 8, and reach the white sheet 5 located on the reading surface of the original reading device 2, the white and white of the originals The white of the sheet 5 is compared, the white reference is determined, the threshold value of the black and white signal is set, and the information of the document is read by the document contact type reading device 2.

Next, when the original that has passed through the reading device 2 reaches and is conveyed by the full-width roller 3 with a step for conveying the original mounted on the original discharge side, tension is applied to the original, so that the original is read from the reading position. A force acts in the floating direction, and the white sheet moving guide 9 integrated with the white sheet 5 also tries to move in the floating direction by the force, but the white sheet floating prevention spring 6 prevents the white sheet 5 from floating. Then, the document is conveyed while being in close contact with the reading surface of the reading device 2.

Further, since the white sheet movement 9 integrated with the white sheet 5 moves up and down in accordance with the document floating direction, the document is conveyed while being pushed by the white sheet 5 by the force of the white sheet floating prevention spring 6. Nevertheless, it is possible to pass the white sheet surface in a very stable state.

[0012]

As described above, according to the present invention, the document floating prevention guide is provided, and the white sheet moving guide that moves following the document floating direction is integrated with the white sheet located on the reading surface of the reading device. By providing the white sheet floating prevention spring in the direction in which the force applied by the white sheet moving guide in the document floating direction is canceled, it is possible to prevent the optical reading position from varying even for documents of various thicknesses.

Further, since there is a step in the central portion of the stepped full width roller for conveying an original, there is an effect that a load is reduced when an original is conveyed and skew is less likely to occur.

[Brief description of drawings]

FIG. 1 is a front view (a) and a side view (b) of an embodiment of the present invention.

FIG. 2 is a diagram for explaining an image reading mechanism of a first conventional example (a) and a second conventional example (b).

[Explanation of symbols]

 1 Automatic Paper Feeding Mechanism 2 Reading Device 3 Full Width Roller with Steps for Document Transport 4 Paper Guide 5 White Sheet 6 Reading Device Lifting Prevention Spring 7 Closed Open Frame 8 Lifting Prevention Guide 9 Moving Guide

Claims (1)

[Claims] 1. A full-width roller with a central step for bringing an original into close contact with a surface of a device for reading an image in close contact with an original, and a white sheet used for white reference determination when the device reads an original, An automatic paper feed mechanism that conveys a plurality of originals one by one, and when the originals fed by the automatic paper feed mechanism are conveyed by the full width roller, the originals are prevented from floating from the reading surface of the device. A floating prevention guide, a moving guide that has a fulcrum on the opening / closing frame and moves integrally with the white sheet to follow the floating direction of the document, and a floating prevention spring that acts in a direction that hinders the movement of the moving guide. An image reading mechanism characterized by the above.