JP2011109240A - Document reader - Google Patents

Abstract

An image reading apparatus capable of reading a document simply by inserting the document without setting each thickness of the document to read a document having a different thickness.
A pair of conveying rollers for conveying an original with a predetermined contact pressure, a detecting means for detecting the thickness of the original, and a link for changing a gap for conveying the original in accordance with the thickness of the original. The mechanism 300 includes a control unit that determines the thickness of the document based on the detection result and operates the link mechanism 300 to create a gap corresponding to the thickness. The detecting means 200 detects the amount of bending of one of the conveying rollers when the original is inserted into the pair of conveying rollers 100.
[Selection] Figure 5

Description

The present invention relates to a document reading apparatus.

As a document reading device that reads data on documents having different thicknesses, there is a device such as that disclosed in Japanese Patent Application Laid-Open No. H10-228707.
JP-A-6-276371

  However, this configuration has to be set for each thickness of a document to be read, and it is difficult to continuously read documents having different thicknesses.

  In order to solve the above-described problems, the present invention provides a pair of conveyance rollers that convey an original document with a predetermined contact pressure, a detection unit that detects the thickness of the original, and an original corresponding to the thickness of the original. A link mechanism that varies the gap to be controlled, and a control unit that determines the thickness of the document based on the detection result and operates the link mechanism to create a gap corresponding to the thickness, and includes a pair of conveying rollers. One is biased toward the other transport roller by the biasing means, and the detection means detects the amount of deflection of one transport roller when the original is inserted into the pair of transport rollers.

  With the above configuration, according to the present invention, it is possible to read a document with a simple configuration, simply by biting the document between a pair of transport rollers, without being installed for each thickness of the document to be read.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic diagram of an image reading apparatus of the present invention. This apparatus is an image scanner that can be connected to a print output apparatus such as an LED printer that reads a large-size paper document P up to A0 size, for example, and is also used in a copier in which the scanner section and the printer section are integrated. .

  The image scanner includes a main body 610 that reads data written on a document P, a lid 510 that can be lifted up and down by a link mechanism 300 in accordance with the thickness of the document P, and a document. A pair of transport rollers 100 that transports P. Note that the data described in the document P refers to images, characters, or data including these.

  The main body 610 includes a reading unit 600, and a feed roller 620 and a discharge roller 630 disposed so as to sandwich the reading unit 600. The reading unit 600 is a reduction optical system, and is an image in which a first mirror M1, a second mirror M2, a third mirror M3, a fourth mirror M4, a projection lens L, and an imaging element are arranged in a line. The sensor S, two light sources (L 1 and L 2), and a fixed base 640 are included.

  In order to allow the light of the light source reflected on the document P to reach the image sensor S, the first mirror M1, the second mirror M2, the third mirror M3, and the fourth mirror M4 have a predetermined angle on the fixed base 640. Are arranged. With this configuration, the light of the light sources (L1, L2) reflected on the document P is projected through the first mirror M1, the second mirror M2, and the third mirror M3, the fourth mirror M4. The light is condensed by the lens L and read by the image sensor S.

  The lid 510 includes a front pressing roller 520, a platen roller 540, and a rear pressing roller 530. The front pressing roller 520 is disposed on the document insertion side, and is attached at a position facing the feed roller 620 when set at a position for reading the document P. As a result, a conveyance path for the document P is formed. The front pressing roller 520 and the feed roller 620, the rear pressing roller 530, and the discharge roller 630 form a pair of conveying rollers 100, respectively.

  Further, the rear presser roller 530 is disposed on the document discharge side, and is attached to a position facing the discharge roller 630 when set to a position for reading the document P. Further, as shown in FIG. 2B, the front presser roller 520 and the rear presser roller 530 have two or more small rollers 700 arranged on the axis.

  More specifically, in the small roller 700 of the front pressing roller 520 and the small roller 700 of the rear pressing roller 530, as shown in FIG. 2, the support shaft 710 extends in the width direction of the roller. The support shaft 710 is rotatably attached to an attachment member 800 provided on the lid 510.

  Further, the mounting member 800 is provided with a groove 810. The groove 810 is formed in a direction perpendicular to the axial direction of the small roller 700 (so-called long groove) so that the support shaft 710 can be shifted upward. This is because even if there is a variation in the thickness of the original P to be read, the support shaft 710 is shifted along the groove 810 to cooperate with the biasing means 820 described later to absorb this variation. In addition, this is because when the thick original P is read, the feed roller 620 and the front pressing roller 520 are bitten.

  An urging means 820 is attached to the support shaft 710 and the attachment member 800 provided on the lid 510. Thereby, the small roller 700 of the front pressing roller 520 and the small roller 700 of the rear pressing roller 530 are urged so that a force acts on the feed roller 620 and the discharge roller 630 side, respectively. The attachment member 800 is configured to cover the upper side of the small roller 700.

  A detection unit 200 is provided above the small roller 700. The detection means 200 is an optical sensor composed of a light emitting unit 210 and a light receiving unit 220. The upper surface of the mounting member 800 that covers the small roller 700 serving as the detection piece 230 is irradiated with the light of the light emitting unit 210, the reflected light is received by the light receiving unit 220, and the reflected light is changed to a voltage. Based on the value, the deflection of the biasing means 820, that is, the thickness of the read original P is detected.

  Here, as will be described, the feed roller 620 and the discharge roller 630 are also provided with two or more small rollers 700 on the axis, similarly to the front pressing roller 520 and the rear pressing roller 530. However, the difference between the front pressing roller 520 and the rear pressing roller 530 is that the biasing means 820 and the detection means 200 are not provided.

  Further, the lid 510 side into which the document P is inserted has an introduction portion 501 whose gap becomes narrower toward the reading means 600 side so as to be easily inserted into the front pressing roller 520 and the feeding roller 620 side, and a predetermined amount. A regulating unit 502 that regulates the conveyance of the document P having the above thickness is provided.

  The platen roller 540 guides the document P sent from the front pressing roller 520 above the contact glass, and fits the document P on the contact glass, that is, the reading position (reading surface).

  The link mechanism 300 varies the gap that the document P conveys in accordance with the thickness of the document P, and includes a fixed shaft 330, a cam member 320, and a moving shaft 310. The fixed shaft 310 is provided on the side surface of the main body 610.

  The cam member 320 has a substantially arc shape, and one end is fixed to the moving shaft 310. Furthermore, a guide groove 350 cut into an arc shape that restricts an upper limit and a lower limit of the movement of the lid 510 is provided in the interior in accordance with driving of the driving means 900 described later.

  A fixed shaft 330 is movably fitted in the guide groove 350. The fixed shaft 330 becomes a fulcrum when the driving member 900 is driven to move the cam member 320. The cam member 320 is moved using the fixed shaft 330 as a fulcrum, and the lid 510 is shifted upward to a predetermined position.

  The moving shaft 310 is configured such that the lid 510 can be shifted upward along the moving groove 360. The moving groove 360 is provided in the auxiliary member 340 disposed on the side surface of the main body 610.

  The driving means 900 shifts the lid 510 upward via the cam member 320 to form a gap for transporting the document P, and is connected to the moving shaft 310 via transmission means (not shown).

  As shown in FIG. 3, the control unit 400 drives the driving unit 900 to form a gap corresponding to the thickness of the document P based on the detection result of the detection unit 200. The control unit 400 stores a threshold value of a voltage value corresponding to the thickness of the document P. The control unit 400 compares the threshold value with the voltage value detected by the detection unit 200, determines the thickness of the document P being conveyed (read), and drives the drive unit 900 by the thickness. .

  Based on the above configuration, a thin document P is inserted between the feed roller 620 and the front presser roller 520 as shown in FIG. At this time, the detection means 200 detects that the biasing means 820 hardly bends. The control unit 400 determines that the document P is thin from the detection result, drives the feed roller 620 and the front pressing roller 520 without operating the link mechanism 300, and conveys the document P to the reading unit 600 side.

  As shown in FIGS. 4B and 4C, the thick original P is inserted between the feed roller 620 and the front pressing roller 520 in the same manner as before. At this time, the detection means 200 detects that the biasing means 820 is bent. The control unit 400 converts the displacement amount deflected by the urging unit 820 into a voltage value, and compares the converted voltage value with a threshold value of the voltage value corresponding to the thickness of the document P stored in the control unit 400.

  Thereafter, in order to obtain a gap corresponding to the thickness of the original P, the driving means 900 is driven from the state shown in FIG. 5A as shown in FIG. 5B as shown in FIG. When the driving unit 900 is driven, the moving shaft 310 moves along the moving groove 360 and moves upward.

  As the moving shaft 310 moves, the cam member 320 moves in the arrow direction b along the guide groove 350 with the fixed shaft 310 as a fulcrum. As a result, a gap (conveyance unit) corresponding to the thickness of the document P is formed.

  Even if the thickness of the document P varies, the pressure (nip pressure) generated between the feed roller 620 and the front pressing roller 520 on the document P at this time is the action of the urging means 820. Thus, the pressure is appropriate (pressure sufficient to convey the original P).

  Thereafter, the control unit 400 drives the feed roller 620 and the front pressing roller 520 to feed the document P to the reading unit 600 side.

  In this way, the document P can be read with a simple configuration, simply by biting the document P between the pair of transport rollers, without being installed for each thickness of the document P to be read.

1 is a schematic diagram of an image reading apparatus of the present invention. The figure which shows the detail of a front part pressing roller and a rear part pressing roller. The block diagram regarding the control of this invention. 4A and 4B are diagrams illustrating the operation of the detection unit and the biasing unit of the present invention, where FIG. 5A is a diagram illustrating a state where a thin document is conveyed, and FIGS. 5B and 5C are diagrams illustrating a state where a thick document is conveyed. 4A and 4B are diagrams showing a link mechanism of the present invention, in which FIG. 4A is a diagram showing a state where a thin document is conveyed, and FIG. 4B is a diagram showing a state where a thick document is conveyed.

100 Pair of Conveying Rollers 200 Detection Unit 400 Control Unit 500 Guide 600 Reading Unit P Document

Claims (5)

A pair of transport rollers for transporting the document with a predetermined contact pressure; a detecting means for detecting the thickness of the document; a link mechanism for varying a gap for transporting the document according to the thickness of the document; Control means for operating the link mechanism to determine the thickness of the document based on the detection result and to create a gap corresponding to the thickness;
One of the pair of transport rollers is biased toward the other transport roller by the biasing means,
The document reader according to claim 1, wherein the detecting means detects a deflection amount of the one transport roller when the document is inserted into a pair of transport rollers.   2. The document reading apparatus according to claim 1, wherein two or more pairs of the conveying rollers are arranged, and a reading unit that reads the document is provided between the pair of conveying rollers. 3.   The document transport path is a gap between the surfaces of the upper main body provided with one of the pair of transport rollers and the lower main body provided with the other of the pair of transport rollers and the reading unit. The document reading device according to claim 1, wherein A guide for guiding the leading edge of the document between the conveyance rollers is provided on the upper body portion side facing the lower body portion on the river upper side of the pair of conveyance rollers,
The guide is gradually narrowed toward the pair of conveyance rollers, and has an introduction portion that smoothly introduces the document and a regulation portion that regulates conveyance of the document having a thickness greater than or equal to a predetermined thickness. The document reading device according to claim 1, wherein the document reading device is a document reading device.   5. The document reading apparatus according to claim 1, wherein the pair of transport rollers are disposed on both sides of the reading unit, and transports the document from either one of them.

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