Conveying device and image recording apparatus

A conveying device includes: a conveyor for conveying a sheet; a path defining member having a first conveying surface that guides the sheet; and a sensor device for sensing the sheet. The sensor device includes: a sensor casing provided on the path defining member and including a second conveying surface that guides the sheet and a main wall whose outer surface is exposed from the path defining member and contiguous to the first conveying surface; a movable member including (i) a contact portion projecting to a second-conveying-surface side of the main wall through an opening formed in the main wall and (ii) a sensed portion located in the sensor casing and moved by the sheet conveyed on the second conveying surface while contacting the contact portion; and a signal output device, provided in the sensor casing, for sensing the sensed portion to output a signal related to its position.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2013-029341, which was filed on Feb. 18, 2013, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a conveying device and an image recording apparatus including a sensor for sensing a sheet.

2. Description of the Related Art

There is conventionally known an image recording apparatus configured to record an image on a sheet conveyed by a conveyor roller. The conventional image recording apparatus includes: a conveyor roller pair configured to nip and convey a sheet; and a recording device configured to record an image on the sheet conveyed by the conveyor roller pair, for example.

Some image recording apparatuses having the above-described construction include a sensor disposed on a conveyance path to sense the presence or absence of the sheet in order to control operations for supplying a sheet, and determine whether there is a sheet jam or not. For example, disposed on the sheet conveying path is a sensor including, as a unit, a sensing lever with which a sheet is brought into contact, an optical sensor constituted by a light emitter and a light receiver, and an electric circuit for controlling the optical sensor.

SUMMARY OF THE INVENTION

In the image recording apparatus having such construction, a face of the sensor which faces the sheet conveying path is not covered. Thus, the sheet on the conveyance path may get snagged on the sensor, causing a skew or a jam of a sheet. Since the optical sensor is kept exposed to the conveyance path, dust may land on the optical sensor, or the light receiver may erroneously sense light that differs from one emitted from the light emitter.

This invention has been developed to provide a conveying device configured to reliably sense a sheet on a conveyance path and ensure smooth conveyance of the sheet, and an image recording apparatus including such a conveying device.

The present invention provides a conveying device comprising: a conveyor configured to convey a sheet in a conveying direction; a path defining member comprising a first conveying surface that guides the sheet conveyed by the conveyor; and a sensor device configured to sense the sheet conveyed by the conveyor and comprising: a sensor casing comprising a main wall and provided on the path defining member such that an outer surface of the main wall, which is exposed from the path defining member is contiguous to the first conveying surface, the sensor casing further comprising a second conveying surface which guides the sheet conveyed by the conveyor; a movable member comprising (i) a contact portion projecting to a side of the main wall on which the second conveying surface is located, through a casing opening formed in the main wall and (ii) a sensed portion which is located in the sensor casing and moved from a first position to a second position by movement of the sheet that is conveyed on the second conveying surface while contacting the contact portion; and a signal output device provided in the sensor casing and configured to sense a position of the sensed portion to output a signal related to the position of the sensed portion.

DETAILED DESCRIPTION OP THE EMBODIMENT

Hereinafter, there will be described one embodiment of the present invention by reference to the drawings. It is to be understood that the following embodiment is described only by way of example, and the invention may be otherwise embodied with various modifications without departing from the scope and spirit of the invention. A multi-function peripheral (MFP)10is used in a state illustrated inFIG. 1. In the present embodiment, three arrows illustrated inFIG. 1indicate an up and down direction7, a front and rear direction8, and a right and left direction9. In the following explanation, the up and down direction7is defined as an up and down direction of the MFP10illustrated inFIG. 1, i.e., the MFP10being in a normal state. Also, the front and rear direction8is defined by regarding a side of the MFP10on which an opening13is formed as a front side, and the right and left direction9is defined in a state in which the MFP10is seen from the front side.

<Overall Structure of MFP10>

As illustrated inFIG. 1, the MFP10as one example of an image recording apparatus according to the present invention is of a slim type having a generally rectangular parallelepiped shape. A printing section11is provided in a lower portion of the MFP10. The MFP10has various functions such as a facsimile function and a printing function. One example of the printing function of the MFP10is a function for ejecting ink to record an image on one side of a recording sheet12(seeFIG. 2). It is noted that the MFP10may be configured to record images on both sides of the recording sheet12. A conveying device is provided in the MFP10. The conveying device is configured to convey the recording sheet12in the MFP10and includes an inner guide member19, a conveyor unit80, and a sensor unit70which will be described below.

As illustrated inFIG. 1, the opening13is formed in a front face of the printing section11. A supply tray20capable of accommodating recording sheets12of various sizes can be inserted into and removed from the printing section11through the opening13in the front and rear direction8. An output tray21is stacked on the supply tray20. The output tray21is moved together with the supply fray20. The output tray21supports a recording sheet12recorded by a recording unit24which will be described below and discharged by an output roller pair61which will be described below. An upper face of the printing section11is provided with a cover member17. The cover member17pivots about an axis extending in the right and left direction9, with its rear end in the front and rear direction8as a basal end and its front end as a free end. In this structure, the upper face of the printing section11is opened and closed.

As illustrated inFIG. 3, the supply tray20has a box shape opening upward and includes a bottom plate81, a left side plate82, a right side plate83, a front plate84, and an inclined plate85. The left side plate82and the right side plate83project upward respectively from opposite edge portions of the bottom plate81in the right and left direction9. The front plate84projects upward from a front edge portion of the bottom plate81in the front and rear direction8. The output tray21is supported by the left side plate82, the right side plate83, and the front plate84(seeFIG. 1). The inclined plate85extends in a rear upward direction from a rear end of the bottom plate81in the front and rear direction8to guide a recording sheet12to a conveyance path35after the recording sheet12is supplied from a supply unit16.

The bottom plate81can support recording sheets12of a plurality of standard sizes such as the A4 size, the B5 size, the legal size, and the postcard size. The bottom plate81has marks each indicating a position of one of edge portions (a left; edge portion in the example inFIG. 3) of the recording sheet12of a corresponding one of the various standard sizes in the right and left direction9.FIG. 3illustrates “A4”, “B5”, and “Postcard” as examples of the mark, but other marks may be used of course. As illustrated inFIG. 3, provided on the bottom plate81are guide members90,91for positioning a recording sheet or sheets12placed on the bottom plate81by contacting opposite edges of the recording sheet(s)12in the right and left direction. The guide members90,91use center alignment to prevent skew of the recording sheet12and to position the various standard sizes of the recording sheets12placed on the bottom plate81. The center alignment is an operation for aligning a center of each recording sheet12in the right and left direction9to a center of the bottom plate81in the right and left direction9.

A user places the recording sheet(s)12on the bottom plate81such that the center of each recording sheet12is aligned to a center line (as one example of a reference position) of the bottom plate81in the right and left direction9. The user then slides the guide member90(as one example of a positioning member) in the left direction of the right and left direction9to a position indicated by the mark that corresponds to the size of the recording sheet(s)12, so that the guide member90is brought into contact with a right edge of the recording sheet(s)12. The guide member91is slid in the right direction by a pinion gear, not shown, in conjunction with the guide member90and brought into contact with a left edge of the recording sheet(s)12. The recording sheet or sheets12of the various standard sizes placed on the bottom plate81are thus positioned by the guide members90,91using the center alignment.

The printing section11includes a base member100(seeFIG. 4) and an exterior cover14for covering the base member100from above. As illustrated inFIG. 2, components provided in the printing section11include the supply unit16, a conveyor roller pair51, the recording unit24, the output roller pair61, and a platen42. The base member100supports the supply unit16, the conveyor roller pair51, the recording unit24, the output roller pair61, the platen42, side frames120,130, and other components. The base member100is covered with the exterior cover14.

The supply unit16picks up one of the recording sheets12from the supply tray20to supply the recording sheet12to the conveyance path35. The conveyor roller pair51conveys the recording sheet12supplied by the supply unit16into the conveyance path35, to a downstream side in a conveying direction15. The recording unit24ejects ink droplets onto the recording sheet12conveyed by the conveyor roller pair51, to record an image on the recording sheet12. The output roller pair61discharges onto the output tray21the recording sheet12recorded by the recording unit24. The platen42supports a lower side of the recording sheet12conveyed by the conveyor roller pair51.

As illustrated inFIG. 2, the conveyance path35extends from a rear edge portion of the supply tray20. The conveyance path35includes a curved conveyance path33and a straight conveyance path34. The curved conveyance path33curves, with a rear side of the printing section11being as an outside of the path33. The straight conveyance path34extends in the front and rear direction8. The recording sheet12supported on the supply tray20is conveyed so as to make an upward U-turn through the curved conveyance path33from a lower portion thereof and then conveyed frontward in the front and rear direction8through the straight conveyance path34to the recording unit24. After the image recording for the recording unit24, the recording sheet12is conveyed frontward in the front and rear direction8through the straight conveyance path34and discharged onto the output tray21. That is, the recording sheet12is conveyed in the conveying direction15indicated by one-dot chain line arrow inFIG. 2.

The curved conveyance path33is defined by an outer guide member18(as one example of a facing member) and the inner guide member19(as one example of a path defining member) which are opposed to each other with a predetermined, distance therebetween. The outer guide member18serves as an outer wall of the curved conveyance path31, and the inner guide member19serves as an inner wall of the curved conveyance path33. The straight conveyance path34is defined by the recording unit24and the platen42which are opposed to each other with a predetermined distance therebetween at a position where the recording unit24is disposed. That is, each of the guide members18,19forms at least a portion of the conveyance path35.

The outer guide member18is pivotably supported by the base member100which will be described below. Shafts48each extending in the right and left direction9are formed respectively on opposite ends of a lower end portion of the outer guide member18in the right and left direction9. In the present embodiment, each of the shafts48is a projection extending outward from a corresponding one of the opposite ends of the outer guide member18in the right and left direction9. The shafts48are fitted in holes, not shown, formed in the base member100. As a result, the outer guide member18is pivotable between a covering position (indicated by solid lines inFIG. 2) where the outer guide member18covers the curved conveyance path33and an exposing position (indicated by broken lines inFIG. 2) where the outer guide member18exposes the curved conveyance path33.

At the covering position, the outer guide member18defines the curved conveyance path33of the conveyance path35with the inner guide member19. At the exposing position of the outer guide member18, on the other hand, an outside face of the inner guide member19is exposed to an outside of the printing section11. That is, the outer guide member18at the exposing position exposes the curved conveyance path33of the conveyance path35to the outside. As a result, the user of the MFP10can clear a recording sheet12stuck in the curved conveyance path33, in other words, the user can perform a jam clearing operation.

The conveyor unit80includes: the supply unit16disposed upstream of the curved conveyance path33in the conveying direction15; the conveyor roller pair51disposed in the straight conveyance path34at a position located upstream of the recording unit24in the conveying direction15; and the output roller pair61disposed in the straight conveyance path34at a position located downstream of the recording unit24in the conveying direction15.

As illustrated inFIG. 2, the supply unit16is provided above the supply tray20and under the recording trait24in the printing section11. The supply unit16includes a supply roller25(as one example of a first conveyor roller), a supply arm26, and a drive-power transmitting mechanism27. The supply roller25is supported by a shaft at a distal end portion of the supply arm26. The supply arm26pivots in a direction indicated by arrow29about a support shaft28provided on a basal end portion of the supply arm26. As a result, the supply roller25can be moved toward and away from the supply tray20or the recording sheet12supported on the supply tray20. The supply roller25is rotated by a driving force produced by a conveyor motor, not shown, which is transmitted by the drive-power transmitting mechanism27constituted by a plurality of gears. It is noted that the supply roller25may be rotated by a driving force applied from a motor provided independently of the conveyor motor.

As illustrated inFIG. 2, the conveyor roller pair51is constituted by a conveyor roller52(as one example of a second conveyor roller) and pinch rollers53. In the present embodiment, the conveyor roller52is formed by coating an outer circumferential surface of a roller shall with ceramic, for example. Also, a metal cylindrical shaft (e.g., a hollow shaft) is employed as the roller shaft in the present embodiment. However, a concrete structure of the conveyor roller52is not limited to this structure. For example, the conveyor roller52may be (boned by fitting a roller on the roller shaft, and a solid shaft may be employed as the roller shaft.

In the present embodiment, the conveyor roller52is disposed in a lower portion of the straight conveyance path34and contacts a lower side of the recording sheet12conveyed from the curved conveyance path33to the straight conveyance path34. The conveyor roller52is rotated by a driving force applied from a conveyor motor that is capable of rotating forwardly and reversely. On the other hand, the pinch rollers53are disposed in an upper portion of the straight conveyance path34so as to be opposed to the conveyor roller52and contact an upper side of the recording sheet12. The pinch rollers53are rotated by the rotation of the conveyor roller52. The conveyor roller52and the pinch rollers53cooperate to nip the recording sheet12in the up and down direction7to convey the recording sheet12in the conveying direction15.

As illustrated inFIG. 2, the output roller pair61is constituted by an output roller62(as one example of a third conveyor roller) and spurs63. In the present embodiment, the output roller62is disposed in a lower portion of the straight conveyance path34and contacts the lower side of the recording sheet12conveyed through the straight conveyance path34. The output roller62is constituted by a shaft64rotated by a driving force applied from the conveyor motor and rollers65fitted on the shaft64so as to be rotated together with the shaft64. On the other hand, the spurs63are disposed in an upper portion of the straight conveyance path34so as to be opposed to the output roller62and contact the upper side of the recording sheet12. The spurs63are respectively fitted on shafts66and rotated by the rotation of the output roller62. The output roller62and the spurs63cooperate to nip the recording sheet12in the up and down direction7to convey the recording sheet12in the conveying direction15.

As illustrated inFIG. 2, the platen42is provided in a lower portion of the straight conveyance path34and between the conveyor roller pair51and the output roller pair61, that is, the platen42is provided downstream of the conveyor roller pair51in the conveying direction15and upstream of the output roller pair61in the conveying direction15. The platen42is disposed so as to be opposed to the recording unit24in the up and down direction7to support the lower side of the recording sheet12conveyed through the straight conveyance path34.

As illustrated inFIG. 2, the recording unit24is disposed in an upper portion of the straight conveyance path34so as to be opposed to the platen42in the up and down direction7. The recording unit24includes a carriage40and a recording head38. The carriage40is supported by two guide raids45,46. The two guide rails45,46each extending in the right and left direction9are arranged so as to be spaced apart from each other in the front and rear direction8. The carriage40is disposed over the two guide rails45,46and reciprocated along the two guide rails45,46in the right and left direction9ejects a main scanning direction. The recording head38is mounted on the carriage40. A lower face of the recording head38has nozzles39through which the recording head38ejects ink supplied from an ink cartridge, not shown. That is, during the reciprocation of the carriage40in the right and left direction9, the recording head38ejects irk droplets from the nozzles39toward the platen42to record an image on the recording sheet12supported on the platen42.

The cover member17is movable between a covering position (indicated by solid lines inFIG. 2) and an exposing position (indicated by broken lines inFIG. 2). The covering position is a position where the cover member17covers a portion of the straight conveyance path34which is located between the conveyor roller pair51and the output roller pair61(in other words, a portion of the straight conveyance path which is opposed to the recording unit24), and the exposing position is a position where the portion of the straight conveyance path34is exposed by the cover member17. This structure allows the user of the MFP10to clear a recording sheet12stuck in the straight conveyance path34, in other words, the user can perform a jam clearing operation.

As illustrated inFIG. 4, the base member100is constituted by a center base101located at a central portion thereof in the right and left direction9; and side bases102,103contiguous to the center base101in the right and left direction9. The side base102is located on the right side of the center base101, and the side base103on the left side of the center base101. That is, the side bases102,103are spaced apart from each other in the right and left direction9. Also, the center base101is located between the side bases102,103in the right and left direction9. In the present embodiment, the base member100is formed of resin as one member.

The center base101includes: a main board or wall113located at its rear portion in the front and rear direction8; and a main hoard or wall114located at its front portion in the front and rear direction8. The main boards113,114extend between the side bases102,103in the front and rear direction and the right and left direction9. The main boards113,114are spaced apart from each other in the front and rear direction8. The main board113supports components such as the supply unit16, the recording unit24, the conveyor roller pair51, the output roller pair61, and the platen42. The main hoard114supports components such as a control board, not shown, for controlling operations of the MIT10.

As illustrated inFIG. 4, projections115A,115B,116A,116B are provided on opposite edge portions of the upper surface of the main hoard113in the right and left direction9. The projections115A,115B are provided on a right edge portion of the upper surface of the main board113so as to be spaced apart from each other in the front and rear direction8. The projections116A,116B are provided on a left edge portion of the upper surface of the main board113so as to be spaced apart from each other in the front and rear direction8. Also, a generally central portion of each of the projections115A,115B,116A,116B has a threaded hole with which a screw as one example of a fastener is to be engaged.

As illustrated inFIG. 4, the pair of side frames120,130are mounted on the upper surface of the main hoard113at positions spaced apart from each other in the right and left direction9e. Each of the side frames120,130is formed by a sheet metal processing. The side frame120is constituted by a base portion121and a support wall122each shaped like a plate, such that the side frame120has a generally L-shape in cross section in a widthwise direction thereof. The side frame130is constituted by a base portion131and a support wall132each shaped like a plate, such that the side frame130has a generally L-shape in cross section in a widthwise direction thereof.

The base portion121is mounted on the upper surface of the main board113, with its longitudinal direction coinciding with the front and rear direction8. The base portion121has through holes123A,123B which are spaced apart from each other in the front and rear direction8. The projections115A,115B of the main board113are respectively inserted into the through holes123A,123B of the base portion121, and screws are engaged in the respective projections115A115B, whereby the side frame120is secured to the main board113. The support wall122stands on one of opposite edge portions of the base portion121in its widthwise direction. That is, the support wall122in the state in which the side frame120is mounted on the main board113extends upward and in the front and rear direction8. The side frame130has a construction similar to that of the side frame120. That is, the base portion131has through holes133A,133B.

As illustrated inFIG. 5, the guide rails45,46, the supply unit16, the conveyor roller pair51, and the output roller pair61are supported by the side frames120,130. The carriage40(in other words, the recording unit24) is supported by the side frames120,130via the guide rails45,46. That is, the guide rails45,46, the supply unit16, the conveyor roller pair51, the recording unit24, and the output roller pair61are supported by the main board113of the base member100.

The inner guide member19is provided at a rear end portion of the main board113in the front and rear direction8(Len, an upstream end portion of the main board113in the conveying direction15). Also, the inner guide member19is disposed downstream of the supply unit16in the conveying direction15and upstream of the conveyor roller52in the conveying direction15. The curved conveyance path33curves along a rear end portion of the main board113the inner guide member19) from a side of the main beard113nearer to its lower surface to a side of the main board113nearer to its upper surface. The straight conveyance path34is provided so as to extend linearly in the front and rear direction8in a horizontal plane expanding along the upper surface of the main hoard113and a lower surface of the main board114.

As illustrated inFIG. 6, the inner guide member19is constituted by: a first wall portion191extending generally in the up and down direction7and the right and left direction9; and a second wall portion19B contiguous to an upper edge of the first wall portion19A and extending generally in the front and rear direction8and the right and left direction9. That is, the first wall portion19A and the second wall portion19B extend in directions intersecting each other. A plurality of ribs19C are arranged in the right and left direction9on surfaces of the first wall portion19A and the second wall portion19B, and each of the ribs19C extends in the conveying direction15. More specifically, each rib19C extends generally in the up and down direction7on the first wall portion19A and extends generally in the front and rear direction8on the second wall portion19B. Accordingly, in the present embodiment, a first conveying surface defining the curved conveyance path33is an imaginary surface expanding so as to include distal edges of the respectively ribs19C. In a construction having no ribs, on the other hand, the first conveying surface is constituted by the surfaces of the first wall portion19A and the second wall portion19B.

As illustrated inFIGS. 4 and 8, the second wall portion19B of the inner guide member19has an opening19D at its central portion in the right and left direction9(as one example of a widthwise direction). This opening19D exposes an inner space of the inner guide member19which is defined by the first wall portion19A and the second wall portion19B. As illustrated inFIG. 6, this inner space accommodates the sensor unit70. Wall faces defining the inner space include a back or bottom wall face that faces the opening19D in the up and down direction7and that has engaging recessed portions19E.

The outer guide member18pivots between an exposing position illustrated inFIG. 6and a covering position illustrated inFIG. 7about an axis extending in the right and left direction9, with lower and upper ends of the outer guide member18being as a pivotal basal end and a free end, respectively. At the exposing position as illustrated inFIG. 6, the outer guide member18exposes the inner guide member19and the sensor unit70. At the covering position, on the other hand, as illustrated inFIG. 7, the outer guide member18covers the inner guide member19and the sensor unit70in a state in which a space (i.e., the curved conveyance path33) is defined between the outer guide member18and the inner guide member19.

As illustrated inFIGS. 9A and 9B, the sensor unit70is constituted by a sensor casing or housing71, a movable member72, an optical sensor73(as one example of a sensor), a sensor circuit board74, and an urging member78. As illustrated inFIG. 10, the sensor unit70is accommodated in the inner space of the inner guide member19and fastened to the inner guide member19by a screw70A (as one example of a fastener) illustrated inFIG. 8. The sensor unit70senses whether the recording sheet12is present or absent at a position of the sensor unit70and sends the control board a signal relating to a result of the sensing.

As illustrated inFIGS. 9A and 9B, the sensor casing71has a generally rectangular parallelepiped shape opening in its generally entire hack face and contains the movable member72, the optical sensor73, the sensor circuit board74, and the urging member78. As illustrated inFIG. 10, in a state in which the sensor unit70is mounted on the inner guide member19, an outer surface of an upper wall71A (as one example of a main wall) of the sensor casing71is exposed without being closed by the inner guide member19, and the outer surface closes the opening19D of the inner guide member19. More specifically, the outer surface of the upper wall71A of the sensor casing71generally flushes with an outer surface of the second wall portion19B of the inner guide member19.

Provided on the outer surface of the upper wall71A axe a plurality of ribs71B arranged in the right and left direction9, and each of the ribs71B extends in the conveying direction15(i.e., generally in the front and rear direction8). Accordingly, as illustrated in the partially enlarged view inFIG. 6, an imaginary surface expanding so as to include distal edges of the ribs71B provided on the upper wall71A which are exposed from the inner guide member19is a second conveying surface that is contiguous to the first conveying surface of the inner guide member19and guides the recording sheet12conveyed by the conveyor unit80. It is noted that in a construction not having the ribs71B on the upper wall71A, the second conveying surface is constituted by the outer surface of the upper wall71A. That is, the curved conveyance path33is defined by (i) the first conveying surface provided on the first wall portion19A and the second all portion19B of the inner guide member19and (ii) the second conveying surface provided on the outer surface of the upper wall71A of the sensor casing71.

A central portion of the upper well71A in the right and left direction9has a cutout71C (as one example of a casing opining) elongated in the front and rear direction8. A lower face of the sensor casing71is provided with engaged protruding portions71D that are to be inserted in the respective engaging recessed portions19E of the inner guide member19. The sensor casing71also has a partition portion71E that is provided below the outer surface of the upper well71A so as to project rearward (i.e., in a downstream direction in the conveying direction15in a state in which the sensor unit70is mounted). As illustrated in area P enclosed by a broken-line circle inFIG. 11A, an upstream corner portion oldie upper wall71A in the conveying direction15is covered with a distal edge portion of the first wall portion19A. Also, in the state in which the sensor casing71is mounted on the inner guide member19, a front edge of the upper wall71A in the front and rear direction8is located at as rear of the conveyor roller pair51. That is, a downstream edge portion of the upper wall71A in the conveying direction15is located upstream of the conveyor roller pair51in the conveying direction15.

The movable member72is constituted by a pivot shaft75, a contact portion76, and a sensed portion77. An orientation of the movable member72can be switched between a first orientation illustrated inFIG. 11Aand a second orientation illustrated inFIG. 11B. More specifically, when a leading edge of the recording sheet12(i.e., a downstream edge portion thereof in the conveying direction15) is brought into contact with the contact portion76, the orientation of the movable member72is switched from the first orientation to the second orientation. On the other hand, when the trailing edge of the recording sheet12(i.e., an upstream edge portion thereof in the conveying direction15) has passed through the contact portion76, the orientation of the movable member72is switched from the second orientation to the first orientation, it is noted that, when the orientation of the movable member72is switched from the first orientation to the second orientation as described above, the sensed portion77is moved from a first position to a second position, and when the orientation of the movable member72is switched from the second orientation to the first orientation, the sensed portion77is moved from the second position to the first position.

The pivot shaft75extends in the right and left direction9in the sensor casing71and is pivotably supported by the sensor casing71. The contact portion76extends outwardly from an outer circumferential surface of the pivot shaft75, specifically, the contact portion76projects from a central portion of the outer circumferential surface in an axial direction of the pivot shaft75. The sensed portion77also extends outwardly from the outer circumferential surface of the pivot shaft75, specifically, the sensed portion77projects from one of opposite end portions (in the present embodiment, a left end portion) of the our circumferential surface in the axial direction of the pivot shaft75. That is, the contact portion76and the sensed portion77project from the pivot shaft75at different positions in the axial direction of the pivot shaft75. In other words, the sensed portion77is located on a portion of the pivot shaft75which is different in its axial direction from the position at which the cutout71C is formed.

Also, the contact portion76projects through the cutout71C from the outer surface of the pivot shaft75to a side of the upper waft71A nearer to its outer surface (i.e., the second conveying surface). More specifically, in the state inFIG. 9A, the contact portion76projects upward through the cutout71C from the outer surface of the pivot shaft75to a side of the upper wall71A nearer to its outer surface. The sensed portion77projects from the outer surface of the pivot shaft75in a direction that differs from a direction directed toward the cutout71C. More specifically, in the state inFIG. 9A, the sensed portion77projects downward from the outer surface of the pivot shaft75, on a side of the sensor casing71nearer to its rear face. That is, the contact portion76and the sensed portion77respectively project in directions that differ from each other in a circumferential direction of the pivot shaft75.

The optical sensor73is electrically connected to the sensor circuit hoard74and is supported by the sensor circuit board74at a position corresponding to the sensed portion77in the up and down direction7. The optical sensor73is constituted by a light emitter73A and a light receiver73B which are opposed to each other in the right and left direction9. The light emitter73A emits light to the light receiver73B. The light receiver73B is disposed in a path of the light emitted from the light emitter73A to receive the light.

The sensor circuit board74is provided in the sensor casing71on an opposite side of the pivot shaft75from the cutout71C. That is the sensor circuit board74is disposed spaced apart from the upper wall71A and so on by a creepage distance in order to prevent static electricity from transferring from a user's hand to the sensor circuit board74. The sensor circuit board74is an elongated plate member whose length in the right and left direction9is longer than that in the front and rear direction8. The sensor circuit board74supports the optical sensor73on one of opposite end portions of an upper face of the sensor circuit board74in its longitudinal direction (in the present embodiment, a left end portion) and supports a connector74A on the other of the opposite end portions (in the present embodiment, a right end portion). To the connector74A is connected one end of a cable79for electrically connecting between the sensor circuit board74and the control board.

Depending upon whether light has been received by the light receiver73B of the optical sensor73or not, the sensor circuit board74outputs a signal to the control board through the cable79connected to the connector74A. More specifically, when light is received by the light receiver73B, the sensor circuit board74outputs a first signal to the control board. When no light is received by the light receiver73B, on the other band, the sensor circuit board74outputs a second signal that differs from the first signal to the control board. It is noted that the optical sensor73and the sensor circuit board74are one example of a signal output device.

As illustrated inFIG. 10, the cable79extends to an outside of the inner guide member19from a space that is formed in a lower portion of the partition portion71E at a position between the inner guide member19and the sensor casing71. The cable79extends to the control board supported on the upper surface of the main board114, while passing through the ribs provided on the upper surface of the main board113. It is noted thatFIGS. 6 and 10indicate that the partition portion71E is located below the conveyor roller52in the up and down direction7. That is, the partition portion71E is located between the conveyor roller52and the cable79in the up and down direction7.

As illustrated inFIGS. 9A and 11A, the movable member72is urged by the urging member7so as to establish the first orientation in which the sensed portion77is located at the first position. As a result, in the state in which the sensed portion77is located at the first position, the contact portion76of the movable member72projects from the second conveying surface, so that the contact portion76on contact the leading edge of the recording sheet12conveyed by the supply unit16through the curved conveyance path33. At the first position, the sensed portion77is not located in the path of the light emitted from the light emitter73A. That is when the sensed portion77is located at the first position, the light receiver73B receives the light emitted by the light emitter73A. As a result, the sensor circuit board74outputs the first signal to the control board through the cable79connected, to the connector74A.

The recording sheet12conveyed by the supply unit16through the curved conveyance path33is brought into contact with the contact portion76to pivot the movable member72against an urging force of the urging member78such that the movable member72takes the second orientation in which the sensed portion77is located at the second position as illustrated inFIG. 11B. That is, when the sensor unit70is seen in the direction as illustrated inFIG. 11B, the pivot shaft75pivots in a counterclockwise direction. Also, the distal end of the contact portion76is moved by the recording sheet12toward a downstream side in the conveying direction15. Also, the sensed portion77is moved in a direction toward the first wall portion19A and away from the cutout71C.

As a result, as illustrated inFIG. 11B, the contact portion76is located below the second conveying surface, so that the recording sheet12can pass through the curved conveyance path33. Since the sensed portion77is located in the light path between the light emitter73A and the light receiver73B, the light receiver73B does not receive the light emitted from the light emitter73A. As a result, the sensor circuit board74outputs the second signal to the control board through the cable79connected to the connector74A.

When the trailing edge of the recording sheet12has conveyed through a position just above the cutout71C (in other words, a position just above the contact portion76), the sensed portion77returns to the first position illustrated inFIG. 11Aby the urging force of the urging member78. As a result, the sensor circuit board74outputs the first signal to the control board through the cable79connected to the connector74A. That is, the sensor circuit hoard74outputs a signal related to the position of the sensed portion77.

<Effects of the Present Embodiment>

In the present embodiment, the inside of the sensor unit70mounted on the inner guide member19is covered with the upper wall71A. Also, the optical sensor73and the sensor circuit board74are disposed at positions far from the cutout71C in the sensor casing71. Also, the cutout71C and the optical sensor73are disposed at different positions from each, other in the axial direction of the pivot shaft75. These structures can prevent a malfunction or damage to the optical sensor73and the sensor circuit board74due to ingress of dust, outside light, static electricity, and so on into the inside of the sensor casing71.

In the present embodiment, the sensor unit70is exposed to an outside of the MFP10by moving the cover member17or the outer guide member18to the exposing position. Thus, the sensor unit70is disposed upstream of the conveyor roller52in the conveying direction15, that is, the sensor unit70is disposed on an opposite side of the conveyor roller52from the cover member17, resulting in reduction in effects of the dust, the outside light, the static electricity, and so on entering from the outside of the MFP10. Likewise, covering the sensor unit70with the first wall portion19A can reduce the effects of the dust, the outside light, the static electricity, and so on entering from the outside of the MFP10. That is, it is possible to reduce effects of the static electricity and so on which are caused in a case where the jam clearing operation is performed in the state in which the cover member17or the outer guide member18is located at the exposing position.

In the present embodiment, when moving from the first position to the second position, the sensed portion77pivots in the direction toward the first wall portion19A in the inner guide member19. Thus, the sensed portion77is provided in advance to project, at its first position, from the pivot shaft75in a direction away from the first wall portion19A, whereby the sensor unit70can be disposed near the first wall portion19A without extending the length of the second wall portion19B in the conveying direction15, resulting in reduction in size of the MFP10in the conveying direction15. Also, when moving from the first position to the second position, the sensed portion77is pivoted in a direction away from the cutout71C, whereby the optical sensor73can be made farther from the cutout71C.

In the present embodiment, the outer surface of the upper wall71A constitutes the second conveying surface defining the curved conveyance path33. Also, the outer surface of the upper wall71A is provided with the ribs71B extending in the conveying direction15. The upstream corner portion of the upper wall71A in the conveying direction15is covered with the distal edge portion of the first wall portion19A. As a result, the recording sheet12can be conveyed smoothly.

In the present embodiment, the partition portion71E is provided between the conveyor roller52and the cable79, preventing the cable79from floating to the position of the conveyance path35and from inhibiting the conveyance of the recording sheet12. Also, the partition portion71E can prevent the dust, the outside light, the static electricity, and so on from entering into the sensor casing71through the space for drawing the cable79.

In the present embodiment, when the sensor unit70is inserted into the inner space of the inner guide member19through the opening19D, the engaged protruding portions71D are respectively inserted into the engaging recessed portions19E. This structure can simply and reliably position the sensor unit70with respect to the inner guide member19. As a result, the first conveying surface and the second conveying surface can be reliably made contiguous to each other by a simple mounting operation, whereby the recording sheet12can be conveyed smoothly.

It is noted that the structure for positioning the sensor unit70with respect to the inner guide member19in the front and rear direction8and the right and left direction9is not limited to the combination of the engaging recessed portions19E and the engaged protruding portions71D. For example, this MFP10may be configured such that engaging protruding portions are provided on the back wall face of the inner guide member19, and engaged recessed portions are provided on a face that faces the back wall face of the sensor casing71. That is, the MFP10only needs to be configured such that protruding portions are provided on one of the sensor unit70and the inner guide member19, and recessed portions for receiving the respective protruding portions are provided on the other of the sensor unit70and the inner guide member19.

In the present embodiment, what is called a center registration is employed. In this type of registration, a change of position due to skew is the least at a center of the recording sheet12in the widthwise direction. Thus, the contact portion76is disposed at the center of the conveying surface in the widthwise direction (i.e., the right and left direction9), making it possible to accurately obtain the position of the recording sheet12using the sensor unit70. This accurate obtainment leads to image recording with high accuracy.

While the MFP10including the inkjet printing section11is explained as one example of the conveying device in the above-described embodiment, the present invention is not limited to this MFP10. For example, the present invention is applicable to a laser printer and a feeder mounted on an image reading apparatus to feed a document.