JP6513145B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming apparatus, and more particularly, to an image reading apparatus for reciprocating a scanning unit for reading an image on a document placed on a document table, and an image forming apparatus including the image reading apparatus It relates to the device.

  Patent Document 1 discloses an example of a conventional image reading apparatus provided with this type of driving device. The drive device of Patent Document 1 applies a tension to a transmission timing belt (traction member) for transmitting the driving force of a drive pulley to a reading unit (scanning unit) for reading image information, and the transmission timing belt. And a tension pulley (follower pulley). And this tension pulley is rotatably supported by the tension pulley stand (pulley holder) fixed to a guide rail.

JP H11-215320 A [H04N 1/04]

  When assembling the drive device of Patent Document 1, the driven pulley is fixed to the pulley holder with a screw or the like, and the pulley holder is fastened to the guide rail with a screw or the like while applying tension to the pulling member. Assembly work) was troublesome. Similarly, when replacing the driven pulley, it is necessary to remove and fasten the screw, and the replacement operation of the driven pulley is time-consuming.

  Therefore, the main object of the present invention is to provide a novel image reading apparatus and image forming apparatus.

  Another object of the present invention is to provide an image reading apparatus and an image forming apparatus capable of easily attaching and detaching a driven pulley to a pulley holder.

  The invention according to claim 1 is an image reading apparatus comprising a document placement table and a scanning unit for reading an image on a document placed on the document placement table, and a guide shaft for guiding the reciprocating movement of the scanning unit A pulling member disposed on the front side of the image reading device with respect to the guide shaft and pulling the scanning unit, a driving pulley transmitting the driving force to the pulling member, and the pulling member being wound in a state where tension is applied to the pulling member The driven pulley, the pulley shaft rotatably holding the driven pulley, and the driven pulley can be locked from the pulley shaft side, and the driven pulley can be inclined toward the axial center side of the pulley shaft by elastic deformation. The pulley holder has a locking claw that can be released from the locking position, and the locking claw is from the pulling member at the circumferential direction position of the driven pulley than at the axial center of the pulley shaft. A position of the tension acting direction side of the movement pulley, and at the position of the front side of the axial center of the pulley shaft, to lock the driven pulley, an image reading apparatus.

  According to the first aspect of the invention, the pulley holder is provided with the locking claw capable of locking the driven pulley from the pulley shaft side and capable of releasing the locking with the driven pulley by elastic deformation. By simply inserting the driven pulley into the pulley shaft, it is possible to hold the driven pulley in a rotatable and disengaged state with respect to the pulley holder. The driven pulley can be removed from the pulley holder simply by pulling the driven pulley from the pulley shaft while inclining the locking claw toward the axial center. That is, the driven pulley can be easily attached to and detached from the pulley holder.

  In addition, since a screw, a washer, and the like are not required when attaching the driven pulley to the pulley shaft, the number of parts can be reduced, and thus the manufacturing cost can be reduced.

  The invention according to claim 2 is according to the invention according to claim 1 and is a holding member for mounting an axial center of a drive pulley, an axial center of a driven pulley (that is, an axial center of a pulley shaft), and a pulley holder in an image reader. The center of is an image reading device arranged on a straight line.

  The invention of claim 3 is an image reading apparatus according to the invention of claim 1 or 2, wherein the pulley holder has two locking claws.

  According to the invention of claim 3, since the pulley holder has two locking claws, the driven pulley can be more reliably prevented from coming off.

  The invention according to claim 4 is according to any one of claims 1 to 3, and the holding member for mounting the pulley holder in the image reading apparatus is disposed on the tensioning direction side with respect to the pulley shaft. It is a reader.

  According to the invention of claim 4, since the holding member is arranged on the tension acting direction side of the pulling member with respect to the pulley shaft, the pulley shaft and the driven pulley can be arranged in the vicinity of the side plate of the housing of the image reading device It is possible to miniaturize the image reading apparatus in the sub scanning direction.

  The invention according to claim 5 is according to any one of claims 1 to 4, and the pulley holder has an elongated hole through which a holding member for mounting the pulley holder in the image reading apparatus is inserted, and the shaft of the pulley shaft An image reader mounted in the image reader movably in a linear direction extending from a center in a tensioning direction.

The invention of claim 6 is according to any one of claims 1 to 5, and the pulley holder is integrally formed with the pulley holder, and is upward at a position on a line extending in the tensioning direction from the axial center of the pulley shaft. It further has a protruding protrusion.

  The invention according to claim 7 is according to any one of claims 1 to 6, and the pulley shaft has a groove-like notch formed by notching a part in the circumferential direction, and the locking claw is The image reading apparatus is provided at a position corresponding to the notch.

  The invention according to an eighth aspect is according to any one of the first to seventh aspects, further comprising a guide portion for guiding the movement of the pulley holder, and a protrusion slidably abutting on the side surface of the pulley holder with respect to the guide portion. A part is formed, which is an image reading apparatus.

  The invention of claim 9 is an image forming apparatus comprising the image reading apparatus according to any one of claims 1 to 8.

  According to the invention of claim 9, as in the invention of claim 1, the driven pulley can be easily attached to and detached from the pulley holder, and the number of parts can be reduced. In addition, even in the state where tension is applied to the pulling member, the locking claw does not easily come off from the upper end portion of the driven pulley.

  A tenth aspect of the present invention is an image forming apparatus according to the ninth aspect of the present invention, comprising an operation unit disposed on the front side of the image reading apparatus.

  According to the present invention, the pulley holder is provided with the locking claw capable of locking the driven pulley from the pulley shaft side and capable of releasing the locking with the driven pulley by elastic deformation. For this reason, the driven pulley can be held in a rotatably and disengaged state with respect to the pulley holder only by fitting the driven pulley into the pulley shaft. The driven pulley can be removed from the pulley holder simply by pulling the driven pulley from the pulley shaft while inclining the locking claw toward the axial center. That is, the driven pulley can be easily attached to and detached from the pulley holder.

  The above-described objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments given with reference to the drawings.

FIG. 1 is an illustrative view showing an outer appearance of an image forming apparatus provided with an image reading apparatus according to a first embodiment of the present invention; It is a top view which shows the internal structure of the image reading apparatus of FIG. FIG. 2 is a cross sectional view schematically showing a longitudinal cross section of the image reading apparatus of FIG. 1; FIG. 2 is a partially enlarged perspective view showing the configuration of a part of a drive device provided in the image reading apparatus of FIG. 1; FIG. 6 is an illustrative view showing a pulley holder provided in the drive device of FIG. 4, (a) is a perspective view of the pulley holder, (b) is a plan view of the pulley holder, and (c) is a side view of the pulley holder as viewed from the front side It is. It is an illustration figure which expands and shows the front-end | tip part of the latching claw with which the pulley holder of FIG. 5 is provided. It is an illustration figure for demonstrating the arrangement position of the latching claw in a pulley shaft. FIG. 7 is an illustrative view showing a pulley holder provided in a drive device of an image reading apparatus according to a second embodiment of the present invention, (a) is a perspective view of the pulley holder, (b) is a plan view of the pulley holder, (c) These are the side views which looked at a pulley holder from the back side. FIG. 7 is an illustrative view showing a pulley holder provided in a drive device of an image reading apparatus according to a third embodiment of the present invention, (a) is a perspective view of the pulley holder, (b) is a plan view of the pulley holder, (c) These are the side views which looked at the pulley holder from the front side.

[First embodiment]
Hereinafter, an image reading apparatus 100 according to a first embodiment of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is an illustrative view showing an appearance of an image forming apparatus 102 provided with an image reading apparatus 100. 2 is a plan view showing the internal configuration of the image reading apparatus 100, and FIG. 3 is a cross-sectional view schematically showing a longitudinal section of the image reading apparatus 100. As shown in FIG.

  Referring to FIGS. 1 to 3, the image reading apparatus 100 includes a driving device 10 for reciprocating the scanning unit 32 in the sub scanning direction, and forms an image such as a copying machine, a facsimile, a printer, and a complex machine thereof. Used in the device 102. In this embodiment, the image forming apparatus 102 is a multifunction peripheral (MFP) having a copy function, a printer function, a scanner function, a facsimile function, and the like.

  First, the basic configuration of the image forming apparatus 102 will be schematically described. As shown in FIGS. 1 to 3, the image forming apparatus 102 includes the apparatus main body 12 and the image reading apparatus 100 disposed thereabove, and image data read by the image reading apparatus 100 or transmitted from an external computer Based on the image data, a multi-color or single-color image is formed on a predetermined sheet (recording sheet).

  A control unit 14 that controls the operation of each part of the image forming apparatus 102 is provided at a predetermined position in the apparatus main body 12. The control unit 14 includes a CPU, a memory, and the like, transmits control signals to each portion of the image forming apparatus 102 in response to an input operation to the operation unit 16 such as a touch panel and operation buttons, Run the action of

  Further, an image forming unit 18 including an exposure unit, a photosensitive drum, a charger, a developing device, a fixing roller, and the like is provided in the apparatus body 12. The image forming unit 18 forms an image on a recording sheet conveyed from the sheet feeding cassette 20 or the like, and discharges the recording sheet on which the image is formed to the discharge tray 22.

  The image reading apparatus 100 includes a housing 24 having a rectangular flat bottom plate 24a and a side wall 24b rising from the periphery thereof. A document placement table 26 formed of a transparent material is provided on the top surface of the case 24. Further, the document pressing cover 28 is attached to the upper side of the document placing table 26 via a hinge or the like so as to be freely opened and closed. The document holding cover 28 is provided with an automatic document feeder (ADF) 30 for automatically feeding the document placed on the document tray one sheet at a time to the image reading position. In addition, on the front side of the housing 24, an operation unit 16 such as a touch panel and operation buttons for receiving an input operation by the user is provided.

  In the housing 24, a CIS (Contact Image Sensor) scanning body 32 for reading an image on a document placed on the document placement table 26, a guide shaft 34, and a CIS scan below the document placement table 26 A drive 10 or the like for reciprocating the body 32 is provided. As described later, when the image on the document placed on the document placement table 26 is read, the CIS scanning body 32 reciprocates below the document placement plate 26 to read the image on the document, Acquire the image data. On the other hand, when reading an image on a document placed on the document tray, the CIS scanning body 32 stands by below a predetermined image reading position, and the document conveyed by the ADF 30 is an image reading position (CIS scanning body When the document passes through 32), the image on the original is read and its image data is acquired.

  The CIS scanning body (scanning unit) 32 is a so-called contact type image sensor, and includes a light source, a rod lens array, a plurality of imaging elements (photoelectric conversion elements), and the like. The light source is, for example, an LED array in which a plurality of LEDs are arranged, and illuminates the surface of the document. The rod lens array condenses the reflected light from the document onto a plurality of imaging elements. The plurality of imaging elements read pixel information imaged by the rod lens array. Instead of the CIS scanner 32, a scanning unit using a CCD (Charge Coupled Device) sensor can also be used.

  The guide shaft 34 guides the reciprocation of the CIS scanning body 32 and extends on the bottom plate 24 a of the housing 24 in the moving direction (sub-scanning direction) of the CIS scanning body 32. The CIS scanner 32 is movably supported by the guide shaft 34, and reciprocates below the document placing table 26 by obtaining a driving force from the driving device 10.

  Subsequently, the configuration of the drive device 10 will be specifically described with reference to FIGS. As shown in FIGS. 2 and 3, the drive device 10 includes a drive pulley 36, a driven pulley 38, a pulling member 40 and the like.

  The drive pulley 36 is provided near one end of the guide shaft 34, and the driven pulley 38 is provided near the other end of the guide shaft 34. An endless belt-like pulling member 40 is wound (wound) around the drive pulley 36 and the driven pulley 38, and the CIS scanner 32 is connected to the pulling member 40. The drive pulley 36 is rotated by a motor as a drive source, and transmits the drive force to the traction member 40. The pulling member 40 is configured by a timing belt, a wire, a chain, or the like, and pulls the CIS scanning body 32 by circumferential movement as the drive pulley 36 rotates. Thus, the CIS scanner 32 is reciprocated along the guide shaft 34. The driven pulley 38 applies a predetermined tension to the pulling member 40, and rotates in accordance with the circumferential movement of the pulling member 40.

  Hereinafter, the support structure of the driven pulley 38 will be described. FIG. 4 is a partially enlarged perspective view showing a configuration of a part (a peripheral part of the driven pulley 38) of the drive device 10 provided in the image reading apparatus 100. As shown in FIG. FIG. 5 is an illustrative view showing a pulley holder 42 provided in the drive device 10, where (a) is a perspective view of the pulley holder 42, (b) is a plan view of the pulley holder 42, and (c) is a pulley holder 42. It is a side view seen from the front side. FIG. 6 is a partial cross-sectional view showing a tip end portion of the locking claw 56 provided in the pulley holder 42 in an enlarged manner. FIG. 7 is an illustrative view for explaining an arrangement position of the locking claw 56 on the pulley shaft 44. As shown in FIG.

  As shown in FIG. 4, the driven pulley 38 is attached to the bottom plate 24 a of the housing 24 using a pulley holder 42. Specifically, in a state where the driven pulley 38 is rotatably supported by a pulley shaft 44 formed in the pulley holder 42, the pulley holder 42 is attached to the bottom plate 24a by a holding member 46 such as a washer and a step screw. The pulley holder 42 is slidable in the sub-scanning direction by being fitted in a guide portion 48 which protrudes in a substantially U shape from the bottom plate 24 a. Further, at an end of the pulley holder 42 on the drive pulley 36 side, a tension applying member 50 which is an elastic member such as a spring is provided. The pulley holder 42 is biased by the tension applying member 50 in such a direction as to apply tension to the pulling member 40, that is, in a direction to move the driven pulley 38 away from the drive pulley 36 along the guide shaft 34.

  Subsequently, a specific configuration of the pulley holder 42 will be described. As shown in FIG. 5, the pulley holder 42 includes a holder body 52, a spring mounting portion 54, and a pulley shaft 44 having a locking claw 56, which are integrally molded of synthetic resin or the like.

  The holder main body 52 is formed in a rectangular flat plate shape, and a short cylindrical spring mounting portion 54 is formed on the end face of the drive pulley 36 side (that is, the direction side in which the driven pulley 38 is pulled by the pulling member 40). . In the first embodiment, the direction in which the driven pulley 38 is pulled by the pulling member 40 is referred to as the tension application direction from the pulling member 40 to the driven pulley 38. The tension applying member 50 described above is attached to the spring attachment portion 54. Further, a pulley shaft 44 is formed at an end portion of the holder main body 52 opposite to the spring mounting portion 54 so as to project upward. The specific configuration of the pulley shaft 44 will be described later.

  Further, a long hole 60 is formed in the central portion of the holder main body 52 so that the position of the pulley holder 42 can be adjusted in the sub scanning direction. Then, the above-mentioned holding member 46 is fixed to the bottom plate 24 a through the long holes 60. That is, the holding member 46 for mounting the pulley holder 42 in the housing 24 of the image reading apparatus 100 is closer to the drive pulley 36 than the pulley shaft 44 supporting the driven pulley 38 (tension from the pulling member 40 to the driven pulley 38 Direction side). Specifically, in this embodiment, the holding member 46 is disposed on a line L extending from the axial center C of the pulley shaft 44 in the tensioning direction by the pulling member 40 (the axial center C and the line L refer to FIG. 7). Ru. Thus, by arranging the holding member 46 on the tension acting direction side of the pulling member 40 rather than the pulley shaft 44, the pulley shaft 44 and the driven pulley 38 can be arranged in the vicinity of the side plate 24b of the housing 24. Miniaturization in the sub-scanning direction of 100 is possible.

  Further, protrusions 62 having a substantially semicircular cross section are formed on both side surfaces of the holder main body 52 (both end surfaces in the direction orthogonal to the tension application direction by the pulling member 40). The contact area between the holder main body 52 and the guide portion 48 is reduced by the contact of the tip end portion of the projection 62 with the above-described guide portion 48, and the frictional force between the holder main body 52 and the guide portion 48 is reduced. . Accordingly, the pulley holder 42 can slide smoothly in the guide portion 48.

  Next, a specific configuration of the pulley shaft 44 will be described. As shown in FIG. 5, the pulley shaft 44 is a support shaft rotatably supporting the driven pulley 38, and includes a shaft main body 64 formed in a substantially cylindrical shape. The outer diameter of the shaft main body 64 is set to be substantially the same as the inner diameter of the driven pulley 38, and the inner surface of the driven pulley 38 slides on the outer surface of the shaft main body 64, and the driven pulley 38 rotates. . Further, a part of the shaft body 64 in the circumferential direction is cut out, and a locking claw 56 for locking the upper end portion of the driven pulley 38 is formed in the cut portion. In the first embodiment, among the circumferential positions on the pulley shaft 44, one locking claw 56 is disposed on the tensioning direction side from the pulling member 40 to the driven pulley 38. Specifically, the locking claw 56 is a line extending in the tensioning direction by the pulling member 40 through the axial center C of the pulley shaft 44 and is disposed closest to the driving pulley 36. That is, in this embodiment, the axial center of the drive pulley 36, the axial center of the driven pulley 38 (that is, the axial center C of the pulley shaft 44), the center of the locking claw 56, and the center of the holding member 46 are straight. It is arranged on a line (see FIG. 2).

  The locking claw 56 includes a tilting piece 56a projecting outward from the inner side surface of the shaft main body 64 and rising upward, and a locking piece 56b extending outward from the tip of the tilting piece 56a. The upper end portion of the driven pulley 38 is locked by the locking piece 56b, whereby the driven pulley 38 rotatably held by the pulley shaft 44 is prevented from coming off (see FIGS. 4 and 6). Further, the width dimension of the tilting piece 56 a in the radial direction of the pulley shaft 44 is formed smaller than the width dimension in the circumferential direction of the pulley shaft 44. That is, the tilting piece 56 a (the locking claw 56) is difficult to tilt in the circumferential direction side of the pulley shaft 44, but has a shape that is easy to tilt toward the axial center C side of the pulley shaft 44. The locking claw 56 can be released from the locking with the driven pulley 38 by tilting toward the axial center C of the pulley shaft 44 by elastic deformation. Further, a flat reinforcing portion 66 is integrally formed at the lower end portion of the locking claw 56.

  Further, as can be clearly understood from FIG. 6, on the upper end portion (upper surface of the tip end portion) on the outer side of the locking claw 56, a linear inclined surface 56c having a downward slope toward the outer side is formed. When attaching the driven pulley 38 to the pulley shaft 44 by forming the inclined surface 56 c, the lower end portion of the pulley shaft 44 abuts on the inclined surface 56 c so that the locking claw 56 naturally becomes the shaft of the pulley shaft 44. It will tilt toward the center C side. Therefore, the attachment of the driven pulley 38 is facilitated.

  Further, the upper end surface of the locking claw 56 is a flat surface 56 d extending in a direction orthogonal to the axial center C of the pulley shaft 44. By making the upper end surface of the locking claw 56 a flat surface 56 d, the height dimension of the locking claw 56 can be suppressed to a low level, and the pulley holder 42 can be thinned.

  Further, at the upper end portion of the locking claw 56 on the side of the axial center C, an arc-shaped (R-shaped) inclined surface 56 e is formed to be a downward slope toward the axial center C of the pulley shaft 44. By forming the inclined surface 56e, the locking claw 56 can be largely inclined toward the axial center C side of the pulley shaft 44 when the driven pulley 38 is attached and detached. That is, since the locking claw 56 tilts with its lower end as a fulcrum, the upper end thereof is largely inclined, but the inclined surface 56 e is formed at the upper end of the locking claw 56 on the axial center C side (that is, By eliminating the corner portion, it becomes difficult to interfere with the shaft main body 64 when the locking claw 56 is tilted. If the locking claw 56 can be largely inclined toward the axial center C side of the pulley shaft 44, the hooking amount (locking length) of the locking claw 56 to the driven pulley 38 is increased by that amount. Because the locking pawl 56 can prevent the driven pulley 38 from coming off more reliably. The effect of forming such an inclined surface 56e is particularly remarkable when forming a plurality of locking claws 56 on the pulley shaft 44 as in the third embodiment described later. This is because the locking claws 56 can be prevented from tilting and interfering with each other.

  In the first embodiment, the inclined surface 56c is a linear inclined surface, and the inclined surface 56e is an arc-shaped inclined surface. However, the inclined surface 56c may be an arc-shaped inclined surface, or the inclined surface 56e may be a linear inclined surface.

  Here, the arrangement position of the locking claw 56 in the circumferential direction of the pulley shaft 44 is the side where the driven pulley 38 is pulled by the pulling member 40 (the tension application direction side (see FIG. 7) It is preferable that it is). This is because when the locking claw 56 is disposed on the opposite side to the tension acting direction from the pulling member 40 to the driven pulley 38, there is a risk that the locking claw 56 may be detached by a load from the pulling member 40. is there. That is, in a state where tension is applied to the pulling member 40, the driven pulley 38 is pulled by the pulling member 40. The locking claws 56 are formed so as to be tiltable (easily bendable) toward the axial center C of the pulley shaft 44, and therefore, the locking claws are provided in the opposite direction to the tension acting direction from the pulling member 40 to the driven pulley 38. When 56 is disposed, the locking claw 56 is bent toward the axial center C of the pulley shaft 44 by the load from the pulling member 40. If this deflection becomes large, the driven pulley 38 will be in a state of riding on the tip of the locking claw 56, and the locking of the driven pulley 38 by the locking claw 56 will be released. As a result, the driven pulley 38 rotates in a state in which the tip of the locking claw 56 is in contact with the driven pulley 38, and the rotational load of the driven pulley 38 is increased. As a result, the pulley shaft 44 and the driven pulley 38 may be damaged. Therefore, as described above, the locking claw 56 is preferably disposed on the tensioning direction side from the pulling member 40 to the driven pulley 38 rather than the position farthest from the driving pulley 36.

  As shown in FIG. 7, in the present invention, in the tension application direction side indicating the arrangement position of the locking claw 56, the driven pulley 38 applies tension to the pulling member 40 (tension by the driven pulley 38) It can also be said that the range other than the application direction). Among them, preferably, in the circumferential direction position of the pulley shaft 44, the locking claw 56 is within a range R of 270 ° with the line L extending in the tension acting direction from the axial center C of the pulley shaft 44 as a center line (center). Two in a clockwise direction and a counterclockwise direction with respect to a line L extending in the tensioning direction from the axial center C, that is, in the tensioning direction side (the drive pulley 36 side). It is placed within a range R of 270 ° between the lines. More preferably, the locking claw 56 is on the tension application direction side (drive pulley 36 side), and with the line L extending in the tension application direction from the axial center C of the pulley shaft 44 as a center line, It is disposed at a position (range) on a line passing through the axial center C and orthogonal to a line extending in the tensioning direction. Particularly preferably, the locking claw 56 is at a position where it is most difficult to receive the load from the pulling member 40, and specifically, the tensioning action by the pulling member 40 from the axial center C of the pulley shaft 44 as shown in FIG. It is disposed on the line L extending in the direction, that is, the position closest to the drive pulley 36.

  In the pulley holder 42 having the pulley shaft 44 having such a configuration, the driven pulley 38 can be attached to the pulley shaft 44 simply by pressing the driven pulley 38 from above and fitting it into the pulley shaft 44. In a state where the driven pulley 38 is attached to the pulley shaft 44 (in use), the upper end portion of the driven pulley 38 is locked by the locking piece 56b of the locking claw 56, thereby reliably preventing the driven pulley 38 from coming off Be done. Further, at the time of replacement or maintenance of the pulling member 40, the driven pulley 38, etc., the driven pulley 38 can be removed from the pulley shaft 44 simply by pulling out the driven pulley 38 while tilting the locking claw 56 toward the shaft center C by elastic deformation. It can be removed.

  According to the first embodiment, the upper end portion of the driven pulley 38 can be locked with respect to the pulley shaft 44 provided in the pulley holder 42, and is driven toward the shaft center C by elastic deformation. A locking claw 56 capable of releasing the locking with the pulley 38 is provided. For this reason, only by fitting the driven pulley 38 into the pulley shaft 44, the driven pulley 38 can be held rotatable and prevented from coming off with respect to the pulley holder 42 (pulley shaft 44). That is, the work of attaching the driven pulley 38 to the pulley holder 42 is facilitated. Further, when the driven pulley 38 is removed, it is only necessary to pull out the driven pulley 38 from the pulley shaft 44 while tilting the locking claw 56 toward the axial center C, so the removal operation of the driven pulley 38 also becomes easy. That is, according to the first embodiment, the driven pulley 38 can be easily attached to and detached from the pulley holder 42.

  Further, according to the first embodiment, when the driven pulley 38 is attached to the pulley shaft 44, an attachment member such as a screw or a washer is not required. Therefore, the number of parts can be reduced and thus the manufacturing cost can be reduced.

  Furthermore, according to the first embodiment, since the locking claw 56 is disposed on the tension application direction side from the pulling member 40 to the driven pulley 38 than the position farthest from the driving pulley 36, tension is applied to the pulling member 40 Even in the closed state, the locking claw 56 does not easily come off the upper end portion of the driven pulley 38. In particular, in the first embodiment, the locking claw 56 is disposed at a position closest to the drive pulley 36, which is the position most difficult to receive the load from the pulling member 40. Therefore, the pulley shaft 44 is more stably driven. The pulley 38 can be held.

Second Embodiment
Next, an image reading apparatus 100 according to a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the arrangement position of the locking claw 56 is different from that of the above-described first embodiment. The configuration of the other parts is the same, so parts common to the first embodiment described above are denoted by the same reference numerals, and redundant description will be omitted or simplified. And only the structure of the pulley holder 42 with which the drive device 10 of the image reading apparatus 100 of this 2nd Example is equipped is demonstrated below. FIG. 8 is an illustrative view showing a pulley holder 42 provided in the drive device 10 of the image reading apparatus 100, (a) is a perspective view of the pulley holder 42, (b) is a plan view of the pulley holder 42, (c) Is a side view of the pulley holder 42 viewed from the back side.

  As shown in FIG. 8, the pulley holder 42 includes a holder body 52, a spring mounting portion 54, and a pulley shaft 44 having a locking claw 56, which are integrally molded of synthetic resin or the like. The locking claw 56 includes a tilting piece 56a and a locking piece 56b, and the width dimension in the radial direction of the pulley shaft 44 of the tilting piece 56a is formed smaller than the width dimension in the circumferential direction of the pulley shaft 44.

  In the second embodiment, the locking claw 56 is disposed on a line perpendicular to a line extending in the tension acting direction through the axial center C of the pulley shaft 44 in the circumferential direction position on the pulley shaft 44. When the locking claw 56 is disposed at such a position, the load from the pulling member 40 is mainly applied to the shaft main body 64 in a state in which the pulling member 40 is under tension, so the load applied to the locking claw 56 is reduced. . Further, since the locking claws 56 are shaped so as not to be inclined with respect to the circumferential direction side of the pulley shaft 44, even if a load is received from the pulling member 40, the locking claws 56 are not easily bent in the tension acting direction. Therefore, the locking claw 56 can not easily come off the upper end portion of the driven pulley 38, and the pulley shaft 44 can stably hold the driven pulley 38.

  According to the second embodiment, since the pulley shaft 44 has the locking claws 56, the driven pulley 38 can be easily attached to and detached from the pulley holder 42 as in the first embodiment described above.

  Further, according to the second embodiment, since the locking claw 56 is disposed on the tensioning direction side from the pulling member 40 to the driven pulley 38 than the position farthest from the driving pulley 36, tension is applied to the pulling member 40. Even in the closed state, the locking claw 56 does not easily come off the upper end portion of the driven pulley 38.

  In the second embodiment, the locking claw 56 is disposed on the back side in FIG. 8, but of course, the locking claw 56 may be disposed on the opposite side, that is, the front side.

Third Embodiment
Subsequently, an image reading apparatus 100 according to a third embodiment of the present invention will be described with reference to FIG. The third embodiment differs from the first and second embodiments in that two locking claws 56 are formed on the pulley shaft 44. The configuration of the other parts is the same, so parts common to the first and second embodiments described above are denoted by the same reference numerals, and redundant description will be omitted or simplified. And only the structure of the pulley holder 42 with which the drive device 10 of the image reading apparatus 100 of this 3rd Example is equipped is demonstrated below. FIG. 9 is an illustrative view showing a pulley holder 42 provided in the drive device 10 of the image reading apparatus 100, (a) is a perspective view of the pulley holder 42, (b) is a plan view of the pulley holder 42, (c) These are the side views which looked at the pulley holder 42 from the back surface side.

  As shown in FIG. 9, the pulley holder 42 includes a holder main body 52, a spring mounting portion 54, and a pulley shaft 44 having a locking claw 56, which are integrally molded of synthetic resin or the like.

  The pulley shaft 44 includes a shaft main body 64 formed in a substantially cylindrical shape. The shaft main body 64 is notched at two places on a line orthogonal to a line extending through the axial center C of the pulley shaft 44 in the tensioning direction, and the locking claws 56 are formed in each of the notched portions. That is, in the third embodiment, the pulley shaft 44 has two locking claws 56, and the two locking claws 56 center a line extending in the tensioning direction through the axial center C of the pulley shaft 44. It is arranged in line symmetry as a line.

  The locking claw 56 includes a rectangular plate-like tilting piece 56a projecting upward from the holder main body 52, and a locking piece 56b extending outward from the tip end of the tilting piece 56a. Further, the width dimension of the tilting piece 56 a in the radial direction of the pulley shaft 44 is formed smaller than the width dimension in the circumferential direction of the pulley shaft 44. Further, at the upper end portion on the side of the axial center C of the locking claw 56, an arc-shaped inclined surface 56e having a downward slope toward the axial center C of the pulley shaft 44 is formed (see FIG. 6). When two locking claws 56 are formed, each of the two locking claws 56 tilts toward the axial center C when the driven pulley 38 is demounted, but the axial center C side of the locking claw 56 is formed. By forming the inclined surface 56e at the upper end portion of the hook, the locking claws 56 are less likely to interfere with each other.

  According to the third embodiment, since the pulley shaft 44 has the locking claws 56, the driven pulley 38 can be easily attached to and detached from the pulley holder 42 as in the first embodiment described above.

  Further, according to the third embodiment, since the locking claw 56 is disposed on the tensioning direction side from the pulling member 40 to the driven pulley 38 than the position farthest from the driving pulley 36, tension is applied to the pulling member 40. Even in the closed state, the locking claw 56 does not easily come off the upper end portion of the driven pulley 38.

  Furthermore, according to the third embodiment, since the pulley shaft 44 has two locking claws 56, the driven pulley 38 can be more reliably prevented from coming off. Further, at this time, since the two locking claws 56 are disposed in line symmetry with a line extending in the tension acting direction passing through the axial center C of the pulley shaft 44, the pulley shaft 44 balances the driven pulley 38 It can be rotated well.

  The specific shape of the locking claw 56 is not limited to the shape shown in the first to third embodiments, and the upper end portion of the driven pulley 38 can be locked, and is elastically deformed. Thus, any shape can be adopted as long as the locking with the driven pulley 38 can be released by tilting toward the axial center C side.

  In each of the first to third embodiments described above, the drive unit 10 is configured for the image forming apparatus (multifunction machine) 102 in which the image reading apparatus 100 and the apparatus main body 12 including the image forming unit 18 are integrated. Although applied, it is not limited to this. For example, the image reading device 100 provided with the driving device 10 may be a separate product. That is, the driving device 10 may be applied to the image reading apparatus 100 having only the scanner function. In this case, the image reading apparatus 100 is connected to a network, for example, and transmits the read image to a personal computer or another image forming apparatus.

  The above-described specific numerical values such as dimensions and angles are merely examples, and can be appropriately changed according to the requirements of the product and the like.

DESCRIPTION OF SYMBOLS 10 ... Drive device 12 ... Device main body of image forming device 18 ... Image formation part 24 ... Case of image reading device 26 ... Document mounting base 32 ... Scanning unit (CIS scanning body)
34 ... guide shaft 36 ... drive pulley 38 ... driven pulley 40 ... traction member 42 ... pulley holder 44 ... pulley shaft 46 ... holding member 50 ... tension application member 56 ... locking claw 56 a ... tilting piece 56 b ... locking piece 56 c ... inclined surface 56d ... flat surface 56e ... inclined surface 100 ... image reading device 102 ... image forming device (multifunction machine)

Claims (10)

An image reading apparatus comprising: a document placement table; and a scanning unit for reading an image on a document placed on the document placement table,
A guide shaft for guiding the reciprocating movement of the scanning unit;
A pulling member disposed on the front side of the image reading device with respect to the guide shaft and pulling the scanning unit;
A driving pulley for transmitting a driving force to the pulling member;
A driven pulley around which the pulling member is wound while tension is applied to the pulling member, a pulley shaft rotatably holding the driven pulley, and the driven pulley can be locked from the pulley shaft side. A pulley holder having a locking claw which can be released from locking with the driven pulley by tilting toward the axial center side of the pulley shaft by elastic deformation;
The locking claw is a position on the tension application direction side from the pulling member to the driven pulley with respect to an axial center of the pulley shaft among circumferential positions of the driven pulley, and the shaft of the pulley shaft The image reader according to claim 1, wherein the driven pulley is locked at a position on the front side with respect to a center.   The image reading apparatus according to claim 1, wherein an axial center of the drive pulley, an axial center of the driven pulley, and a center of a holding member for mounting the pulley holder in the image reading apparatus are arranged in a straight line. .   The image reader according to claim 1, wherein the pulley holder has two of the locking claws.   The image reading device according to any one of claims 1 to 3, wherein a holding member for attaching the pulley holder in the image reading device is disposed closer to the tension acting direction than the pulley shaft.   The pulley holder has an elongated hole through which a holding member for mounting the pulley holder in the image reading apparatus is inserted, and the image reading is movably possible in a linear direction extending in the tension acting direction from an axial center of the pulley shaft. The image reading apparatus according to any one of claims 1 to 4, mounted in the apparatus. 6. The pulley holder according to claim 1, further comprising: a projection formed integrally with the pulley holder and projecting upward at a position on a line extending in the tensioning direction from an axial center of the pulley shaft. Image reader. The pulley shaft has a groove-like notch formed by notching a part in the circumferential direction,
The image reading device according to any one of claims 1 to 6, wherein the locking claw is provided at a position corresponding to the notch. A guide unit for guiding the movement of the pulley holder;
The image reading apparatus according to any one of claims 1 to 7, wherein a projection that slidably contacts the guide is formed on a side surface of the pulley holder.   An image forming apparatus comprising the image reading apparatus according to any one of claims 1 to 8.   The image forming apparatus according to claim 9, further comprising: an operation unit disposed on a front side of the image reading apparatus.

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