JP4755001B2 - Document conveying apparatus and image processing apparatus - Google Patents

Description

  The present invention relates to an original conveying apparatus and an image processing apparatus, and more particularly to an original forming apparatus mounted on an image forming apparatus such as a copying machine, a facsimile apparatus and a printer, an image reading apparatus such as a scanner, or the like.

  Document transport devices mounted on image forming devices such as copiers, facsimile machines and printers, and image reading devices such as scanners, etc., feed a document or printing paper loaded on a platen into the device by a feed roller. To do. At this time, if the document feeding roller is driven in a state where the document is not stacked on the document table or the document is loaded at a position where the document does not contact the sheet feeding roller at the time of feeding, the sheet feeding roller rubs against the document table, The surface of the paper feed roller is worn and the conveying force is reduced.

  In addition, dust is generated when the paper feed roller rubs against the document table, and when the dust enters the apparatus, it adheres to each member in the apparatus and causes a conveyance failure. In an image reading apparatus or an image forming apparatus, Reading failure or image printing failure may occur. In addition, noise may occur due to rubbing between the feed roller and the document table. Also, in order to provide a function of automatically starting feeding when a document is stacked on the document table, it is necessary to detect the presence or absence of the document on the document table in the vicinity of the sheet feed roller.

  FIG. 4A shows conventional document detection means for detecting a document on a document table by shielding a photosensor using a mechanical lever (see, for example, Patent Document 1).

  In the document detection means shown in FIG. 4A, a lever 41 is disposed in the vicinity of the feed roller of the document table, and the lever 41 rotates when the lever 41 is pushed by the document leading edge 25 of the document D that passes through the conveyance path 40. It has a configuration. The rotating lever 41 detects the document by shielding the photo interrupter 42 disposed in the vicinity of the lever.

  Further, FIG. 5A shows a document detection means for detecting a document on a document table using a reflection type optical detection element integrated with a light projecting / receiving element.

In the document detection means shown in FIG. 5A, a substrate 51 having a reflection type optical detection element 50 in which both light projecting and receiving elements are integrated is arranged below the document table 2, and the document D is stacked on the document table 2. Then, the light P from the light emitting element 50a is reflected by the original D and is incident on the light receiving element 50b to detect the original.
JP-A-8-119493 (FIG. 10 on page 6)

  However, the document detection means on the document table described above has the following problems.

  (1) In the document detection means using the mechanical lever shown in FIG. 4A for light shielding of the photosensor, as shown in FIG. The leading edge 25 of the document D may be bent due to the rotation load of the lever 41. When the document D is loaded, the lever 41 is always in contact with the document D, and the document D and the detection lever 41 rub when the document is conveyed. For this reason, there is a possibility that the detection lever 41 may be worn out and erroneously detected if it is used for a long time.

  (2) In the document detection means using the reflection type optical detection element in which the light projecting and receiving elements shown in FIG. 5 (a) are integrated, the effective range of the sensor is generally short and the effective range is narrow. In order to accurately detect the document D mounted on the substrate 2, the substrate 51 on which the reflective optical detection element 50 is mounted must be disposed on the document table side and very close to the document stacking surface, which is limited in layout. End up. For this reason, a dedicated board on which only the reflective optical detection element is mounted is often required. In this case, electrical wiring is also required, which increases the number of parts and the number of assembly steps, resulting in an increase in cost. Further, even if the substrate 51 on which the reflective optical detection element 50 is mounted is disposed in the vicinity of the original stacking surface, as shown in FIG. 5B, the distance from the reflective optical detection element becomes large if the original is bent. , It may not be detected.

  The present invention has been made in view of the above problems, and reliably detects the presence or absence of a document fed from a document table by a feed roller without erroneous detection due to wear of a mechanical part or bending of the document. Provided are a document conveying device and an image processing device.

In order to achieve the above object, a document conveying device according to claim 1 is a document table on which documents are stacked, a document take-in member that is rotated while being in contact with the document on the document table, and takes in the document; A document conveying device having a document detecting unit for detecting the presence or absence of a document on the document table, wherein the document detecting unit includes a light emitting element disposed on one side of a rotation axis direction of the document taking member. A light receiving element disposed on the other side of the original take-in member in the rotation axis direction, and a light guide member attached to the original table and guiding a light beam emitted from the light emitting element to the light receiving element. It is characterized by.

According to the present invention, the document detecting means includes a light emitting element disposed on one side in the rotation axis direction of the document taking member, and a light receiving element disposed on the other side in the rotation axis direction of the document taking member. And a light guide member that is attached to the document table and guides the light beam emitted from the light emitting element to the light receiving element. Accordingly, it is possible to reliably detect the presence / absence of the document fed from the document table by the feed roller without erroneous detection due to abrasion of the mechanical part or bending of the document.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic structural diagram of an internal view of an image reading apparatus equipped with a document conveying device according to an embodiment of the present invention as viewed from the side. In the figure, the configuration of a scanner, which is an example of an image reading device on which the document conveying device according to the present invention is mounted, is shown, but the configuration is not limited thereto.

  In FIG. 1, an image reading apparatus 1 includes a document table 2 on which a document D is placed, a light projecting / receiving unit 3, a light guide 4, a sheet feeding roller 5, a feeding roller 6, and a separation roller 7. The registration sensor 8, the transport roller pair 9, the image reading units 10 and 11, the paper discharge roller pair 12, and a controller unit (not shown) that controls the overall operation of the image reading apparatus 1.

  The light projecting / receiving unit 3 detects the document D on the document table 2. The light guide 4 guides the light beam irradiated from the light emitting element mounted on the light projecting / receiving unit 3 and incident from the incident surface to the exit surface facing the light receiving element so as to go around the vicinity of the paper feed roller 5.

  The paper feed roller 5 feeds the original D on the original table. The feed roller 6 feeds the document D fed by the feed roller 5 into the apparatus. The separation roller 7 separates the fed documents D one by one. The registration sensor 8 detects the leading edge of the document D fed into the apparatus. The conveyance roller pair 9 conveys the document D fed into the apparatus to the image reading unit (image reading units 10 and 11).

  The image reading unit 10 reads image information on the upper surface (back surface) of the document D. The image reading unit 11 reads image information on the lower surface (front surface) of the document D. The paper discharge roller pair 12 is disposed on the downstream side of the image reading units 10 and 11 and discharges the original D to the outside of the apparatus.

  The image reading apparatus 1 includes an upper frame 1a and a lower frame 1b. The upper frame 1a can be rotated around a rotation shaft 13, and the apparatus can be manually opened and closed.

  Next, the operation at the time of reading the image of the document D in the image reading apparatus 1 will be described. The image reading apparatus 1 is connected to a computer (not shown) directly or via a network or the like, and receives an original reading instruction from the computer.

  When a reading start signal is received from a computer (not shown) after the document D is loaded on the document table 2, the controller unit (not shown) indicates the presence of the document D by blocking light incident on the light receiving element of the light projecting / receiving unit 3. Is recognized, the paper feeding roller 5 is rotated while being pressed against the document D, and the document D is fed to the feeding roller 6. The fed document D is conveyed into the apparatus by the feeding roller 6, but when there are a plurality of documents D fed by the feeding roller 5, they are arranged to face the feeding roller 6. Then, the sheet is separated and conveyed by the separating roller 7. Thereafter, the document D is nipped and conveyed by the pair of conveying rollers 9, and the front and back images are read by the image reading units 10 and 11 and converted into reading signals.

  A controller unit (not shown) reads image data while taking a timing based on a signal from the registration sensor 8 and converting read signals from the image reading units 10 and 11 into digital data. After the image data is read, the document D is discharged outside the apparatus while being nipped and conveyed by the pair of discharge rollers 12.

  Next, the configuration and operation of the document detection means in the image reading apparatus 1 of FIG. 1 will be described with reference to FIGS.

  2A and 2B are diagrams schematically showing the configuration of the document detection means in the image reading apparatus 1 of FIG. 1, wherein FIG. 2A is a perspective view and FIG. 2B is a front view. 3A and 3B are views showing a state of the original detection unit when the original is placed, in which FIG. 3A is a perspective view and FIG. 3B is a front view.

  In FIGS. 3A and 3B, 2 is a document table, 5 is a paper feed roller, and 14 is a paper feed roller holder that pivotally supports the paper feed roller 5. The document detection means includes a light emitting element 3a, a light receiving element 3b, a light projecting / receiving unit 3 provided with the light emitting element 3a and the light receiving element 3b, and a light beam L emitted from the light emitting element 3a. The light guide 4 is made incident from the incident surface 4a and emitted from the exit surface 4d.

  The light projecting / receiving unit 3 and the light guide 4 are in a paper feeding operation (paper feeding roller) when the optical path of the light beam L emitted from the light emitting element 3a toward the incident surface 4a on the original table is blocked by the original D. The document D is disposed at a position where the document D can be reliably fed by the feed roller 5 at the time of rotation 5.

  Since the light emitting element 3a and the light receiving element 3b reliably detect a narrow original and feed it by the paper feeding roller 5, the presence or absence of the original is detected in the vicinity of the place where the paper feeding roller 5 and the original D are in contact with each other. Since they need to be detected, they are arranged in the vicinity of the end of the sheet feeding roller 5 in the direction of the rotation axis as shown in the figure.

  The light emitting element 3a is attached to the light projecting / receiving unit 3 at a predetermined angle with respect to the vertical direction at a position facing the incident surface 4a on the document table. On the other hand, the light receiving element 3b is disposed in the vicinity of the end of the paper feed roller 5 on the side opposite to the light emitting element 3a with the paper feed roller 5 interposed therebetween. The light receiving element 3b is attached to the light projecting / receiving unit 3 at a position facing the exit surface 4d on the document table and inclined at a predetermined angle with respect to the vertical direction.

  The light guide 4 is formed by elongating a transparent resin material such as acrylic or polycarbonate into a substantially U shape, and each end face is used as an entrance surface 4a and an exit surface 4d to place a document on the document table. It is attached to the document table 2 so as to be the same as the surface. The entrance surface 4a and the exit surface 4d of the light guide 4 are on a tangent line where the document table 2 and the paper feed roller 5 are close to each other, and are provided at a predetermined interval on the document table side. Thus, when the document D is detected, the document D can be detected at a position where the paper feeding roller 5 can reliably feed the paper.

  The light guide 4 includes a first bent portion 4b bent at a predetermined angle to change the traveling direction of the light beam incident from the incident surface 4a, and the light beam whose traveling direction is changed by the first bent portion 4b. And a second bent portion 4c bent at a predetermined angle in order to change the traveling direction toward the exit surface 4d. The first bent portion 4b and the second bent portion 4c of the light guide 4 are such that the light flux L incident on the light guide 4 is totally reflected into the light guide 4 without leaking outside (air layer) ( The shape satisfies Snell's law. Further, the angles of the first bent portion 4b and the second bent portion 4c are set to be substantially right angles or obtuse angles so as to be the same angle according to Snell's law.

  The light beam L emitted from the light emitting element 3 a is incident substantially perpendicular to the incident surface 4 a of the light guide 4 or substantially parallel to the central axis of the light guide 4. The light beam L incident from the incident surface 4a of the light guide 4 is totally reflected by the first bent portion 4b and the second bent portion 4c, is emitted from the emission surface 4d, and reaches the light receiving element 3b.

  As shown in FIGS. 2A and 2B, in the state where the document D is not on the document table, the light beam L emitted from the light emitting element 3a travels on the above-described optical path and reaches the light receiving element 3b. be able to. On the other hand, as shown in FIGS. 3A and 3B, in a state where the document D is stacked on the document table, the light beam L emitted from the light emitting element 3 a is reflected on the document stacked on the document table 2. The light is shielded by D and is not incident on the light guide 4 and cannot reach the light receiving element 3b. As a result, by determining whether or not the light beam L from the light emitting element 3a is blocked by the document D, the presence or absence of the document D placed on the document table can be reliably detected.

  According to the above-described embodiment, the document detection means for detecting the presence or absence of the document D placed on the document table is disposed in the vicinity of one end in the rotation axis direction of the paper feed roller 5, The light emitting element 3a that irradiates the light beam L toward the incident surface 4a, and the light beam L from the light emitting element 3a is incident from the incident surface 4a and totally reflected by the first bent portion 4b and the second bent portion 4c. A light guide 4 that exits from the exit surface 4d and a light receiving element 3b that is disposed in the vicinity of the other end in the rotational axis direction of the paper feed roller 5 and that receives the light beam L emitted from the exit surface 4d on the document table. With. Accordingly, it is possible to reliably detect the presence or absence of the document D fed from the document table by the sheet feeding roller 5 without erroneous detection due to abrasion of the mechanical part or bending of the document.

  In addition, by providing at least one of the entrance surface 4 a and the exit surface 4 d on an extension line of a line where the document table 2 and the paper feed roller 5 are in contact with each other, the original document D can be moved back to a position where it does not contact the paper feed roller 5. It is determined that there is no wear, and wear of the paper feed roller 5 can be prevented.

  In addition, since the degree of freedom of arrangement of the substrate on which the photosensor is mounted is higher than that of the above-described conventional document detection means, the substrate can be integrated with another substrate disposed around the document detection means, Costs can be reduced by reducing the number of parts and man-hours for electrical wiring. In addition, since either the portion incident on the light guide 4 or the portion emitted from the light guide 4 only needs to be blocked by the document D, the presence or absence of the document can be determined for a document having a hole or a damaged document. It can be detected more accurately.

  In the above embodiment, the light guide 4 is formed by molding a transparent resin material such as acrylic or polycarbonate. However, the light guide 4 is not limited to this, and guides the light beam emitted from the light emitting element 3a to the light receiving element 3b. If so, it may be constituted by a mirror or a prism. The light guide 4 may be a light guide such as an optical fiber having an incident surface and a light exit surface having a predetermined area. Moreover, the light guide which bundled the optical fiber etc. may be sufficient.

  The light receiving element 3b in the above embodiment may include an electronic circuit such as a waveform shaping circuit or an output buffer in addition to a phototransistor or a photodiode.

  Further, the image reading apparatus 1 in the above embodiment includes the image reading units 10 and 11 that read the front and back images of the document D. However, the image reading apparatus 1 may include only one of the image reading units. Good. Further, it goes without saying that the present invention includes the case where the document conveying apparatus according to the present invention is mounted on an image forming apparatus such as a copying machine, a facsimile apparatus, or a printer. The document conveying device image according to the present invention may be externally attached to the image reading device or the image forming device.

1 is a schematic structural diagram of an inside of an image reading apparatus on which a document conveying device according to an embodiment of the present invention is mounted as viewed from the side. FIG. 2 is a diagram schematically illustrating a configuration of a document detection unit in the image reading apparatus 1 of FIG. 1, in which (a) is a perspective view and (b) is a front view. 4A and 4B are diagrams illustrating a state of the original detection unit when the original is placed, where FIG. 5A is a perspective view, and FIG. It is a longitudinal cross-sectional view which shows schematic structure of an example of the conventional document detection means, (a) shows the state at the time of document detection, (b) shows the state at the time of document erroneous detection. It is a longitudinal cross-sectional view which shows schematic structure of the other example of the conventional document detection means, (a) shows the state at the time of document detection, (b) shows the state at the time of document erroneous detection.

Explanation of symbols

D Document L Light beam 1 Image reading device 2 Document table 3 Projecting / receiving unit 3a Light emitting element 3b Light receiving element 4 Light guide 4a Incident surface 4b First bent portion 4c Second bent portion 4d Ejecting surface 5 Feed roller 6 Feeding Roller 7 Separating rollers 10 and 11 Image reading unit 14 Paper feed roller holder

Claims (8)

A manuscript having a manuscript table on which a manuscript is loaded, a manuscript take-in member that is rotated while being in contact with the manuscript on the manuscript table, and a manuscript detection unit that detects the presence of the manuscript on the manuscript table A conveying device,
The document detection means includes a light emitting element disposed on one side of the rotation axis direction of the document capture member;
A light receiving element disposed on the other side in the rotation axis direction of the document take-in member;
And a light guide member that is attached to the document table and guides the light beam emitted from the light emitting element to the light receiving element.   The document detection unit is configured to detect at least one of a light beam emitted from the light emitting element and a light beam emitted from the light guide member after being incident on the light guide member. 2. The document conveying device according to claim 1, wherein the presence of the document is detected when the light is blocked.   3. The document conveying apparatus according to claim 1, wherein the document detection unit includes a light projecting / receiving unit including the light emitting element and the light receiving element.   The light guide member has an incident surface on which the light beam emitted from the light emitting element is incident on the document table and an exit surface from which the light beam is emitted toward the light receiving element, and the light beam incident from the incident surface. 4. The document conveying device according to claim 1, comprising a light guide formed by forming a transparent material into an elongated shape so as to guide the light to the exit surface. 5. 5. The document conveying device according to claim 1, wherein the light guide member is formed so as to be emitted from the emission surface by totally reflecting a light beam incident on the incident surface. 6. . The light guide member has at least two bent portions in which a light beam incident from the incident surface is refracted, and the bent portion totally reflects the light beam incident on the incident surface of the light guide member. Item 5. The document conveying device according to Item 4. 7. The document transport device according to claim 4, wherein the entrance surface and the exit surface are arranged on an extension line of a line segment where the document table and the document take-in member are in contact with each other.   8. An image processing apparatus on which the document conveying device according to claim 1 is mounted, comprising at least one of an image reading unit that reads an image and an image forming unit that forms an image. An image processing apparatus.

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