JP2007230750A - Sheet carrying detection mechanism and sheet carrying device with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet carrying detection mechanism formed in a compact structure in which the number of parts is reduced and capable of surely preventing sheet carrying from being erroneously detected, and to provide a sheet carrying device with the same. <P>SOLUTION: The sheet carrying detection mechanism 4 comprises a detection member 40 and a sensor part 50. The detection member 40 is rotatably journaled on bearing parts 70 and 71. A detection bar 42 is projected from one end of a bar-like rotating shaft 41 and they are formed integrally with each other. An operation bar 43 is projected from the other end thereof, and they are formed integrally with each other. A compression spring 60 is wound around and inserted onto the rotating shaft 41. One end of the compression spring is engaged with the operation bar, and the other end is fixed so that the compression spring is not axially moved. The compression spring 60 biases the operation bar so as to be turned upward and also biases it in the axial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet conveyance detection mechanism that can be applied to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a sheet conveyance apparatus including the sheet conveyance detection mechanism.

  In the image forming apparatus described above, various types of sheets such as postcards and envelopes are conveyed in addition to the standard paper, and the image forming process is performed. When reading an original, the original is conveyed. There is also a type that performs a document reading process and performs an image forming process on a sheet based on the read image data. As described above, when a sheet such as a sheet or a document is transported, a detection mechanism for the transported sheet is provided because it is necessary to synchronize the timing of the image forming process or the image reading process with the sheet transporting operation. . Various detection mechanisms are provided to detect that a sheet has been set and to detect the size of the sheet.

For example, in Patent Document 1, a detection lever is rotatably provided on the upper side of the sheet conveyance path, a photo interrupter is provided on the lower side of the sheet conveyance path, and the detection lever is lifted by the conveyed sheet. The point which detected the sheet | seat is described. Further, in Patent Document 2, when the arm is swingably attached to a filler that shields the transmission type optical sensor, and the arm is rotated only on one side by a torsion coil spring, and the paper is conveyed in the opposite direction. The point that is not detected is described. Patent Document 3 describes that an actuator that rotates by contact of paper is provided, and the displacement of the actuator is detected by a sensor.
JP-A-11-199090 JP 2004-75376 A Japanese Patent Laying-Open No. 2005-298091

  In the conventional sheet conveyance detection mechanism described above, a detection lever or actuator that is rotated by the conveyed sheet is used to detect the rotation operation by a light detection sensor or the like, and the sheet conveyance state is detected. When using the detection member provided so that rotation is possible, there exists a fault which a detection member rotates carelessly and is easy to perform a misdetection. Further, in the image forming apparatus described above, since a large number of sheet conveyance detection mechanisms are provided in the sheet conveyance apparatus, an increase in installation space and an increase in the number of parts may cause an increase in cost and hinder downsizing of the apparatus. There is.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveyance detection mechanism capable of reliably preventing erroneous detection with a compact structure with a reduced number of parts, and a sheet conveyance apparatus including the sheet conveyance detection mechanism.

  A sheet conveyance detection mechanism according to the present invention detects a rotation of a detection member that is pivotally supported so as to be able to rotate in contact with a conveyed sheet while projecting into a sheet conveyance path. And a sensor unit that detects the presence or absence of the sheet, and a predetermined compression biasing member that urges the rotation shaft in the axial direction by a coiled compression spring member wound around the rotation shaft of the detection member. It is characterized by urging in the direction of rotation. Furthermore, the detection member includes a rod-shaped rotation shaft, a detection bar provided on the rotation shaft and protruding into the sheet conveyance path, and an operation bar provided on the rotation shaft and operating the sensor unit. The compression spring member is fixed such that one end thereof does not move in the axial direction of the rotation shaft, and the other end is engaged with the operation bar.

  A sheet conveying apparatus according to the present invention includes the sheet conveyance detecting mechanism described above.

  With the above configuration, the detection member is not prepared because the rotation shaft is biased in a predetermined rotation direction using the compression spring member wound around the rotation shaft of the detection member. When the sheet is conveyed, it can be reliably rotated and detected, and the rotation axis is urged in the axial direction by the compression spring member to detect the axial direction of the detection member. Thus, the detection member can be maintained in a stable state in the axial direction and the rotational direction.

  The compression spring member has a plurality of such functions, so that the number of parts can be reduced, and since it is wound around the rotating shaft and set, almost no installation space is required. Therefore, the structure of the detection mechanism itself can be made compact.

  The detection member includes a rod-shaped rotation shaft, a detection bar provided on the rotation shaft and projecting into the sheet conveyance path, and an operation bar provided on the rotation shaft and operating the sensor unit. The compression spring member is fixed so that one end thereof does not move in the axial direction of the rotation shaft, and the other end is engaged with the operation bar. Therefore, the detection bar and the operation bar are kept in a stable state at predetermined positions. Further, the operating bar itself engages with the compression spring member and is urged in a predetermined rotation direction, so that it is possible to reliably prevent the operating bar from inadvertently operating the sensor unit.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

    FIG. 1 is a schematic sectional view of a document reading apparatus provided with an embodiment according to the present invention. The document reading device 1 includes a document conveying unit 2 and a document reading unit 3, and is carried by the document conveying unit 2 set on the document tray 10 and conveyed to the document reading unit 3. Then, the document read by the document reading unit 3 is discharged to the discharge tray 11.

  The document transport unit 2 is provided with a pickup roller 21 and a separation roller 22, and the document placed on the document tray 10 is drawn by the pickup roller 21, and the leading edge of the document is held by the separation roller 22. The separation roller 22 carries documents one by one, and the leading edge of the loaded document is sandwiched between the feed roller 23 and the press roller 24 and conveyed.

  The document is further conveyed downward along the outer periphery of the feed roller 23 and is sandwiched between the press roller 24 and the feed roller 23. The sandwiched document is conveyed to the reading position along the document guide member 25 disposed close to the lower portion of the feed roller 23.

  A sheet conveyance detection mechanism 4 is provided adjacent to the feed roller 23 on the upstream side in the conveyance direction of the press roller 24, and the detection member 40 rotates when the document carried in by the pickup roller 21 contacts the detection member 40. To detect that the document has arrived. Subsequent conveyance control and reading control are processed according to the detection timing.

  In the document reading section 3, a reading head 30 on which a lamp, an image sensor, and the like are mounted is moved in the left-right direction by a carriage mechanism (not shown). When reading the document conveyed by the document conveying unit 2, the reading head 30 is positioned below the platen glass 31 and is allowed to stand, and the document passing between the document guide member 25 and the platen glass 31 is read. It is supposed to read.

  The read original is guided upward by the guide protrusion 32 and is sandwiched between the discharge roller 26 and the press roller 27. Then, the paper is discharged to the discharge tray 11 by the discharge roller 26.

  The document transport unit 2 also serves as a document cover. When reading a book or the like, the document transport unit 2 is rotated upward so that a portion to be read such as a book is placed on the flat bed platen 33 and read. The reading operation is performed by moving the head 30 in the left-right direction.

  FIG. 2 is an external perspective view of the sheet conveyance detection mechanism 4, and FIG. 3 is an exploded perspective view of the sheet conveyance detection mechanism 4. The sheet conveyance detection mechanism 4 is disposed in a space between the divided roller portions of the field roller 23 that is pivotally supported by the main body frame 28 of the document conveyance unit 2. The sheet conveyance detection mechanism 4 includes a detection member 40 and a sensor unit 50. In the detection member 40, a detection bar 42 protrudes in a direction substantially orthogonal to the axial direction on one end side of a rod-shaped rotation shaft 41. The actuating bar 43 is integrally formed on the other end side so as to project in a direction substantially perpendicular to the axial direction.

  A shaft support portion 44 formed in a double D-cut is provided on the center side of the detection bar 42, and a stopper portion 46 that protrudes in a flange shape in the circumferential direction is formed on the center side of the shaft support portion 44. A compression spring 60 is wound around the other end side of the operating bar 43 so as to be slidable in the direction of the axis T of the rotation shaft 41, and is attached to the other end side of the compression spring 60. Is provided with a shaft support 45 formed in a double D-cut.

  The shaft support portions 44 and 45 are fitted into bearing portions 70 and 71 erected on the main body frame 28 and are rotatably supported. The bearing portion 70 is provided with a support portion 70 a having an inner surface formed in an arc shape and an insertion portion 70 b opened at the top of the support portion 70 a, and the insertion portion 70 b is between the double D cut surfaces of the shaft support portion 44. The support portion 70a is formed in a slightly larger shape than the uncut circular shape of the shaft support portion 44.

  Similarly to the bearing portion 70, the bearing portion 71 is provided with a support portion 71 a and an insertion portion 71 b. Then, the shaft support portions 44 and 45 are inserted into the insertion portions 70b and 71b so that the double-D cut surface is vertical, and the rotation shaft 41 is rotated in the support portions 70a and 71a to double-cut the surface. The shaft support portions 44 and 45 are held so as to be rotatable without being removed from the bearing portions 70 and 7.

  The compression spring 60 is formed by winding a wire rod in a coil shape. One end portion 61 extends downward linearly, and the tip is bent into a hook shape, and is engaged with the lower portion of the operation bar 43. . Further, the other end portion 62 extends linearly downward, and is fitted in a locking groove 72 a of a locking projection 72 that stands adjacent to the bearing portion 71. Since the compression spring 60 is inserted in a compressed and twisted state, the compression bar 60 is urged so as to rotate the operation bar 43 upward by a repulsive force by twisting, and the operation bar 43 is pivoted by a repulsive force by compression. It is biased in the direction T.

  The rotation shaft 41 is rotated by the urging force in the rotation direction R by the compression spring 60, but the plate-like portion 47 integrally formed along the axial direction of the rotation shaft 41 comes into contact with the main body frame 28 and has a predetermined value. It is held in a stable state at the pivot position. By forming the plate-like portion 47, it plays a role as a balancer and contributes to the stability of the detection member 40. Further, the rotating shaft 41 moves in the axial direction by the urging force in the axial direction T by the compression spring 60, but the stopper portion 46 contacts the side surface of the bearing portion 70 and is held in a stable state in the axial direction. The Therefore, the detection member 40 is held in a stable state free from play in the rotation direction and the axial direction by the urging force of the compression spring 60, so that it does not operate carelessly.

  When the compression spring 60 is mounted, as shown in FIG. 3, it is only necessary to insert the shaft support portion 45 into the bearing portion 71 by inserting from the other end side, and it can be easily attached.

  The sensor unit 50 is a transmission type photosensor in which a light emitting unit 51 having a light emitting element and a light receiving unit 52 having a light receiving element are arranged to face each other, and the operation bar 43 enters and exits between the light emitting unit 51 and the light receiving unit 52. Then, the light receiving element detects that the light from the light emitting element is shielded, and detects that the original is carried in.

  FIG. 4 is a view of the operating state of the detection member 40 as viewed from the axial direction of the rotation shaft 41. In a state where the detection member 40 is not in contact with the loaded original (indicated by a solid line), the detection member 40 is The operation bar 43 is held between the light emitting unit 51 and the light receiving unit 52. Therefore, the light of the light emitting element is shielded by the operation bar 43 and the sensor unit 50 is turned off.

  When the loaded document comes into contact with the detection bar 42, the detection member 40 rotates counterclockwise against the urging force of the compression spring 60 and is indicated by a dotted line), so that the operation bar 43 moves downward and the light emitting element. The light receiving element detects the light and the sensor unit 50 is turned on. In this way, the loaded original is detected, and conveyance control and reading control are performed.

  As described above, the sheet conveyance detection mechanism according to the present invention includes the detection member in which the detection bar and the operation bar are integrally formed, the compression spring wound around the rotation shaft of the detection member, and the sensor unit. Simple structure with little installation space. In addition, by urging the detection member in the rotation direction and the axial direction by the compression spring, a plurality of actions can be exerted by one component, and the detection member can be stably operated with few components to perform an inadvertent operation. It can be surely prevented.

  In the above example, the document conveying unit of the document reading device has been described as an example. However, the present invention is not limited to the document conveying device, and various sheet conveying devices such as a sheet conveying device, a postcard, and an envelope of the image forming apparatus, for example. The present invention can also be applied to a device detection mechanism.

1 is a schematic sectional view of an entire document reading apparatus provided with an embodiment according to the present invention. It is an external appearance perspective view regarding a sheet conveyance detection mechanism. It is a disassembled perspective view regarding a sheet conveyance detection mechanism. It is explanatory drawing which shows the operating state of a detection member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Document reading apparatus 2 Document conveyance part 3 Document reading part 4 Sheet conveyance detection mechanism
41 Rotating axis
42 Detection bar
43 Actuator bar
50 Sensor section
60 compression spring
70 Bearing
71 Bearing

Claims (3)

  A detection member that protrudes into the sheet conveyance path and is pivotally supported so as to be rotatable in contact with the conveyed sheet; and a sensor unit that detects the presence or absence of the sheet by detecting the rotation of the detection member; In the sheet conveyance detection mechanism, the coil-shaped compression spring member wound around the rotation shaft of the detection member urges the rotation shaft in the axial direction and urges the rotation shaft in a predetermined rotation direction. A sheet conveyance detection mechanism.   The detection member includes a rod-shaped rotation shaft, a detection bar provided on the rotation shaft and protruding into the sheet conveyance path, and an operation bar provided on the rotation shaft and operating the sensor unit. 2. The compression spring member according to claim 1, wherein one end portion of the compression spring member is fixed so as not to move in an axial direction of the rotation shaft, and the other end portion is engaged with the operation bar. Sheet conveyance detection mechanism.   A sheet conveying apparatus comprising the sheet conveyance detecting mechanism according to claim 1.

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