JP2005263344A - Paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder, precisely detecting the size of paper placed on a paper loading part. <P>SOLUTION: This paper feeder A is adapted to deliver paper sheets set on the paper loading part 2 one by one and feed the same toward a paper transport path 5. A paper presence/absence discriminating sensor 19 and a plurality of paper width detecting sensors 20, 21, 22 are juxtaposed in the width direction above the paper loading part 2, and the paper presence/absence discriminating sensor 19 is positioned on the downstream side of the plurality of paper width detecting sensors 20, 21, 22 in the paper transport direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a paper feeding device that feeds originals and recording paper one by one and feeds them to an image reading unit and a recording unit through a paper conveyance path. More specifically, the present invention relates to a facsimile, a copying machine, a printer, or a combination thereof. The present invention relates to an automatic paper feeder for originals and recording paper in the so-called multi-function machine.

In the above apparatus, it is necessary to recognize in advance the presence and size of a document to be fed or recording paper for image reading control or recording control. Therefore, the document tray of the automatic document feeder (ADF) and the manual feed tray (free tray) for recording paper are provided with a paper presence / absence discrimination sensor and a plurality of paper width detection sensors in parallel. When the paper is set, the presence / absence of the paper and the size are detected. Patent Document 1 relates to a document width detection device in a facsimile apparatus. In FIG. 3 and FIG. 4, a document presence sensor and a plurality of document width sensors are arranged in parallel on a document set unit (document tray). An example is shown.
Japanese Utility Model Publication No. 5-9076

  In the document width detection apparatus disclosed in Patent Document 1, one document presence / absence determination sensor and three document width detection sensors (however, one also serves as a document presence / absence determination sensor) are linear in the width direction. Are installed side by side. The document presence / absence determination sensor is installed at a position that is always turned on when the document is placed on the document tray, and the document width detection sensor is installed at a position corresponding to each document size. Accordingly, the determination of the document width size is based on the premise that the document presence / absence determination sensor is on. In this case, the document presence / absence determination sensor and the maximum width detection sensor (for example, the A3 width detection sensor) are disposed in the most distant positional relationship across the center line of the document tray. Thus, for example, when the operator places an A3 document on the document tray at an angle, the document presence / absence determination sensor (also serving as the A4 width detection sensor) and the B4 width detection sensor are turned on. The detection sensor is turned off, and it may be erroneously determined that the document width is B4 even though the document is an A3 document.

  The document tray of Patent Document 1 is a so-called center reference type that aligns the document with the center in the width direction. Recently, from the viewpoint of simplifying the mechanism of the margin guide, the so-called one-side reference type that aligns with one side in the width direction of the document tray. Are also being used a lot. In the case of such a one-side reference type, the distance between the document presence / absence determination sensor and the document width detection sensor is larger than that of the center reference type, and the above-described erroneous recognition is more likely to occur. Such a problem also occurs in a recording paper feeding device using a manual feed tray, and drastic improvement has been desired.

  The present invention has been made in view of the above circumstances, and provides a paper feeding device capable of accurately detecting the size of a paper placed on a paper placement unit.

  The paper feeding device of the present invention is a paper feeding device for feeding the paper set on the paper placement unit one by one and feeding it to the paper transport path, and on the paper placement unit, A sheet presence / absence determination sensor and a plurality of sheet width detection sensors are juxtaposed in the width direction, and the sheet presence / absence determination sensor is located downstream of the plurality of sheet width detection sensors in the sheet conveyance direction.

  The sheet placing portion sets the sheet so as to follow the reference surface on one side in the width direction as in the invention of claim 2, and the sheet width detection sensor is located at a position near the reference surface. Can be provided at positions separated from the reference plane in the width direction. In this case, as in the invention of claim 3, the sheet width detection sensor is installed so that the sensor for a large size is located farther in the width direction than the reference plane.

  According to the present invention, since the paper presence / absence determination sensor is positioned downstream in the paper conveyance direction from the plurality of paper width detection sensors, even if the paper is placed on the paper placement portion at an angle, it is turned on. It is avoided that the paper width detection sensor to be turned off remains, and an accurate paper size is determined. Therefore, accurate control is performed in subsequent image reading control and recording control by determining the appropriate paper size. In particular, as in the second or third aspect of the invention, the effect is remarkable in a paper feeding device using a so-called one-side reference paper placing portion.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a main part of an automatic document feeder in a facsimile machine, a copying machine, or a so-called multi-function machine having both functions of facsimile and copying, and FIG. 2 is a schematic plan view of a paper feeder including a document tray. It is.

  The automatic document feeder (ADF) 1 shown in the figure is configured as a double-sided image reading device for reading double-sided images and outputting them as digital signals while conveying sheet-by-sheet originals D one by one. A document supply tray 2b is detachably attached to the document supply port 2a of the ADF 1 so as to incline downward toward the document supply port 2a, and a document (paper) is formed by the document supply port 2a and the document supply tray 2b. ) The mounting unit 2 is configured. A pickup roller 3 is provided on the document supply port 2a to feed the document D deposited on the document supply tray 2b from the upper layer portion. The pickup roller 3 is used to separate the fed documents one by one. Document separating means 4 for feeding is provided. The document separating means 4 is composed of a separation roller 4a and a retard roller 4b that is elastically contacted with a peripheral body of the separation roller 4a and is urged to rotate in the opposite direction. The document placing portion 2, the pickup roller 3, and the document separating means 4 constitute the sheet feeding device A of the present invention.

  The document fed out by the pickup roller 3 is introduced between the separation roller 4a and the retard roller 4b, and due to the difference in the coefficient of friction with respect to the two papers due to the rotation of the separation roller 4a and the counter-rotation biasing action of the retard roller 4b. Each sheet is separated and fed downstream. Needless to say, the document separating means 4 may be a combination of a separation roller and a separation pad, instead of the separation roller 4a and the retard roller 4b.

  Documents separated one by one by the document separation means 4 are registered by a registration roller (registration means) 6 and a large-diameter conveyance roller 7 which are sequentially arranged along a document conveyance path 5 formed in a U-turn shape. The oblique state is corrected, the paper is fed toward the reading point P, and is discharged onto the discharge tray 9 by the discharge roller 8 after passing through the reading position. Pressure rollers 6 a, 7 a, 7 b, and 8 a that nip the document D to be fed are elastically contacted with these rollers 6, 7, and 8. The discharge roller 8 can be rotated forward and backward, and when the rear end of the original on which the image on the first surface has been read at the reading point P reaches the discharge roller 8, the discharge roller 8 contacts the pressure roller 8a after the original. Stop once with the end nipped. Thereafter, the document is reversed and passes over the switching gate 10a, and is fed again from the switchback conveyance path 10 (the upper portion of the large-diameter conveyance roller 7) to the reading point P through the document conveyance path 5, and An image on the second surface is configured to be read. A switching gate 10a is installed at a branching portion to the switchback conveying path 10, and this switching gate 10a is switched to a position indicated by a broken line when the discharge roller 8 is reversed and the document D is switched back. Control is performed so that the back conveyance path 10 side is opened.

  A slit glass (platen) 11 is disposed at the reading point P. When the document passes over the slit glass 11, the reading glass P waits below the slit glass 11 (see the two-dot chain line portion in FIG. 1). Image information on the surface of the document is sequentially read by the scanning device 12 and output as a digital signal as described above. The image scanning / scanning device 12 also serves as a flat plate scanning / scanning device (FBS), and a full-rate carriage (scanning carriage) 14 and a box-type scanning / scanning housing 13 having a platen glass 18 installed on the upper surface. A half rate carriage (scanning carriage) 15, a condenser lens unit 16, and a CCD 17 are provided.

  The full rate carriage 14 includes a light source 14b made of a fluorescent lamp or a cold cathode tube and a first mirror 14c mounted on a carriage frame 14a, and is connected to a drive belt 14d and slidable on a guide rail (not shown). And reciprocate left and right within the housing 13 over substantially the entire range. The half-rate carriage 15 includes second and third mirrors 15b and 15c that form an angle of 90 ° on the carriage frame 15a, and is driven at a speed half that of the full-rate carriage drive belt 14d. It is connected to the belt 15d and slidably supported by a guide rail (not shown), and reciprocates left and right within the housing 13 over the range of its substantially left half.

  The drive belts (toothed belts are also possible) 14d and 15d are coaxially mounted on the drive pulleys 14e and 15e having a diameter of 2: 1, and are driven by the same motor (not shown). . Therefore, the full-rate carriage 14 and the half-rate carriage 15 connected to the drive belts 14d and 15d reciprocate so as to follow each other at a speed ratio of 2: 1 by the operation of the motor. The condensing lens unit 16 and the CCD 17 are fixed to the bottom plate 13 a of the housing 13, and when reading the document D 1 placed on the platen glass 18, the full rate stands by on the left side in the housing 13. As the carriage 14 and the half-rate carriage 15 move to the right, the reflected light emitted from the light source 14b to the document D1 is repeatedly reflected by the first to third mirrors 14c, 15b, and 15c, and the condenser lens unit 16 Then, the light is sequentially incident on the CCD 17 to form an image. In the CCD 17, the formed optical information is converted into a digital electric signal and output.

  Further, when reading the ADF document D, as described above, the full-rate carriage 14 moves and stands by at a position directly below the slit glass 11 (the half-rate carriage 15 also stops at a predetermined standby position). The image of the document D continuously conveyed on the slit glass 11 is similarly read by the ADF 1. During such scanning, the light reflected by the document D or D1 follows the optical path L and enters the CCD 17, but the moving speed ratio between the full rate carriage 14 and the half rate carriage 15 is 2: 1. The so-called inter-substance distance is always constant, so that the read image quality is kept constant.

  The ADF 1, the document supply tray 2b, and the discharge tray 9 are integrated to form a platen cover, and can be opened and closed up and down with the back side of the paper surface as a hinge portion (not shown). Therefore, when reading an original using the FBS function, the platen cover is opened and the original is placed on the exposed platen glass 18. Further, as the image reading / scanning device 12, the light source 14 b, the plurality of mirrors 14 c, 15 b, 15 c, the lens unit 16, and the CCD 17 are collectively mounted on one scanning carriage and reciprocated along the lower surface of the platen glass 18. It may be moved.

  The document placing portion 2, the pickup roller 3, and the document separating means 4 constitute the sheet feeding device A of the present invention, which will be described in more detail with reference to FIG. A document guide wall 2c protrudes from one side of the document placement unit 2 (right side in the document feeding direction indicated by the white arrow), and its inner surface (left side) serves as a reference surface 2d. . That is, the paper feeding device A is a right reference type, and the document D is set on the document placement unit 2 so as to follow the reference surface 2d. A document (paper) presence / absence determination sensor 19 is located near the reference surface 2d on the document placement unit 2, and three document (paper) width detection sensors 20 are spaced apart from the reference surface 2d in the width direction. 21 and 22 are arranged in this order.

In the illustrated example, the document placement unit 2 indicates that the maximum size of a document that can be handled is A3 portrait or A4 landscape, where the document width detection sensor 20 is an A4 portrait (A5 landscape) document detection sensor, document width. The detection sensor 21 indicates a B4 vertical (B5 horizontal) original detection sensor, and the original width detection sensor 21 indicates an A3 vertical (A4 horizontal) original detection sensor. The document width detection sensor 20 is at a position within 210 mm from the reference surface 2d, the document width detection sensor 21 is at a position within 256 mm from the reference surface 2d, and the document width detection sensor 22 is at a position within 297 mm from the reference surface 2d. Has been placed. Accordingly, the width size of the document is determined as follows based on the on / off patterns of the sensors 19 to 22 by the document placed on the document tray 2b so as to follow the reference surface 2d. That is,
(1) When the sensor 19 is off, the document has not been placed yet.
(2) When the sensor 19 is on and the other sensors are off, the document is smaller than A4 portrait or A5 landscape.
(3) When the sensor 19 and the sensor 20 are on and the other sensors are off, the document is an A4 portrait or A5 landscape document.
(4) When the sensor 19, the sensor 20, and the sensor 21 are on and the sensor 22 is off, the document is a B4 portrait or B5 landscape document.
(5) When all the sensors are on, the document is an A3 portrait or A4 landscape document.
It is determined.

  A document length detection sensor (not shown) is disposed in the middle of the document transport path 5, and a detection signal when the document passes through the document length detection sensor and the width size determination pattern are provided. Depending on the combination, A4 portrait or A5 landscape, B4 portrait or B5 landscape, A3 portrait or A4 landscape is determined, and the sizes of all usable rated documents are determined. Here, the vertical means that the long side of the original is along the original feeding direction, and the horizontal means that the short side of the original is along the original feeding direction.

  The document width detection sensors 20, 21, and 22 are arranged in a horizontal straight line, but the document presence / absence determination sensor 19 is disposed slightly downstream in the document feeding direction from the document width detection sensors 20, 21, and 22. ing. Accordingly, as shown in FIG. 2, even when the A3 portrait (A4 landscape) document D is placed obliquely, all of the document presence / absence determination sensor 19 and document width detection sensors 20, 21, and 22 are turned on. D is correctly determined to be an A3 portrait or A4 landscape document.

  Incidentally, positions S1, S2, and S3 indicated by imaginary lines in FIG. 2 are installation positions of conventional sensors corresponding to the document width detection sensors 20, 21, and 22, and are aligned with the document presence / absence determination sensor 19 in a horizontal straight line. Indicates that In this case, when the A3 portrait (A4 landscape) document D is placed obliquely as shown in the figure, the sensors corresponding to S1 and S2 are turned on, but the sensor corresponding to S3 may remain off. Therefore, the document D is determined to be a B4 portrait or B5 landscape document. In the case of the one side (right side) reference as shown in the figure, the distance between the document presence / absence determination sensor and the maximum document (A3) width detection sensor is larger than in the case of the center reference, and the document is placed obliquely. The frequency of erroneous size determination is increased, but if the document presence / absence determination sensor 19 is shifted to the downstream side, such trouble can be prevented in advance. This is particularly effective in a paper feeding device having a placement unit.

  In the above embodiment, the document feeding device in the switchback type double-sided reading device has been described. However, the present invention can also be applied to a one-through type double-sided reading device or a document feeding device in a single-sided reading device. Needless to say. Needless to say, the present invention can be applied not only to the image reading apparatus but also to a recording paper feeding apparatus having a free tray in the recording apparatus. Further, it is natural that the number of document width detection sensors 20, 21, and 22 can be changed depending on the specifications of the apparatus (the type and size of paper to be handled).

1 is a longitudinal sectional view of a main part of an automatic document feeder that can be combined with a facsimile machine, a copying machine, or a so-called multifunction machine. FIG. 3 is a schematic plan view of a paper feeding device including a document tray.

Explanation of symbols

2 Document (Paper) Placement Section 2d Reference Surface 5 Document (Paper) Conveyance Path 19 Document (Paper) Presence Sensor 20 Document (Paper) Width Detection Sensor 21 Document (Paper) Width Detection Sensor 22 Document (Paper) Width Detection Sensor A Feeder D Document

Claims (3)

A paper feeding device for feeding out the paper set on the paper placement section one by one and feeding it to the paper transport path,
A sheet presence / absence determination sensor and a plurality of sheet width detection sensors are juxtaposed in the width direction on the sheet placement portion, and the sheet presence / absence determination sensor is located downstream of the plurality of sheet width detection sensors in the sheet conveyance direction. A sheet feeding device characterized by being positioned.   The paper placement unit sets the paper so that it follows the reference surface on one side in the width direction, the paper presence / absence determination sensor is located near the reference surface, and the paper width detection sensor is separated from the reference surface in the width direction. The sheet feeding device according to claim 1, wherein the sheet feeding device is provided at each position.   The sheet feeding device according to claim 2, wherein the sheet width detection sensor is installed such that a sensor for a large size is located at a position away from the reference plane in the width direction.

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