JP5340132B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus for forming an image on a sheet.

  In general, an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions forms an image while conveying a sheet. Many image forming apparatuses convey sheets from a box-shaped cassette in which sheets are stored, and also draw and convey sheets from a tray disposed so as to be exposed from the outside of the image forming apparatus casing. (See, for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-40224

  A sheet feeding mechanism for drawing a sheet placed on a tray into a casing and supplying the sheet to a conveyance path formed in the casing is generally fixedly attached to the casing. Such a structure makes it difficult to take out the jammed sheet downstream of the paper feed mechanism.

  In order to make it easier to take out jammed sheets downstream of the paper feed mechanism, when the paper feed mechanism is movably attached to the housing, it causes difficulty in the paper feed preparation work after the sheet is removed. there is a possibility.

  Thus, at present, there is a demand for a technique that makes it easy to take out a jammed sheet on the downstream side of the sheet feeding mechanism and easily perform a sheet feeding preparation operation after removing the sheet.

  The present invention has been made to solve the above-described problem, and facilitates the removal of a jammed sheet on the downstream side of the sheet feeding mechanism, and facilitates the reinstallation of the sheet feeding mechanism after the sheet is removed. An object of the present invention is to provide an image forming apparatus that can be used.

An image forming apparatus according to one aspect of the present invention cooperates with a housing that houses an image forming portion for forming an image on a sheet, and an inner wall portion formed inside the housing. A transport wall that forms a transport path that extends to the inner wall, the transport wall is close to the inner wall, and a first position that forms the transport path and a second position that the transport wall is spaced from the inner wall A rotation unit attached to the housing so as to be rotatable between the sheet, a paper feed mechanism attached to the rotation unit and for feeding the sheet to the conveyance path, and attached to the housing and the rotation. A control mechanism that is connected to the sheet feeding mechanism and controls the operation of the sheet feeding mechanism when the unit is in the first position, and the sheet feeding mechanism sends the sheet to the conveyance path. A rotating paper feed roller; And a lift plate attached to the rotating unit so as to be at least partially supported and detachable from the paper feed roller, and in conjunction with the control mechanism, the lift plate is separated from the paper feed roller. An operating mechanism formed so as to cause a lock mechanism to lock the lift plate at a position spaced from the paper feed roller and to unlock the lift plate in conjunction with the control mechanism, When the rotation unit is in the second position, the linkage between the operation mechanism and the control mechanism is released, and the lock mechanism locks the lift plate at a position spaced from the paper feed roller. It shall be the.

  According to the above configuration, the rotation unit is rotatably attached to the housing that houses the image forming unit for forming an image on the sheet. The conveyance wall of the rotation unit forms a conveyance path that extends to the image forming unit in cooperation with an inner wall formed inside the housing. The rotation unit is rotatable between the first position and the second position. In the first position, the transfer wall is close to the inner wall and forms a transfer path. In the second position, the transfer wall is spaced from the inner wall. A sheet feeding mechanism for feeding the sheet to the opposite runway is attached to the rotation unit. Accordingly, it is possible to relatively easily remove the jammed sheet generated downstream of the sheet feeding mechanism. The control mechanism attached to the housing is connected to the paper feed mechanism when the rotation unit is in the first position, and controls the operation of the paper feed mechanism. The paper feed roller of the paper feed mechanism rotates to send the sheet to the conveyance path. The lift plate of the paper feed mechanism supports the sheet at least partially and is attached to the rotating unit so as to be detachable from the paper feed roller. Therefore, when the lift plate approaches the paper feed roller, the sheet supported by the lift plate is sent out to the conveyance path by the paper feed roller. The lift plate is separated from the paper feed roller by an operating mechanism that is linked with the control mechanism. The lock mechanism of the paper feed mechanism locks the lift plate at a position away from the paper feed roller and releases the lock on the lift plate in conjunction with the control mechanism. When the rotation unit is in the second position, the linkage between the operation mechanism and the control mechanism is released, and the lock mechanism locks the lift plate at a position away from the paper feed roller. Thus, when the rotating unit is in the second position, a gap is formed between the paper feed roller and the lift plate, so that it is easy to insert a sheet into the gap and facilitate the paper feeding preparation work. It becomes.

In the above configuration, the operating mechanism includes a first elastic member that urges the lift plate toward the paper feed roller, and an operating piece that separates the lift plate from the paper feed roller, and the control mechanism includes , Including a cam piece rotatably attached to the housing, and a rotation locus of the cam piece is interlocked between a first rotation section in which the cam piece is interlocked with the operating piece and the cam piece and the operating piece. The cam piece is formed so as to have a second rotation section that is released, and when the cam piece is in the first rotation section, the operating piece separates the lift plate from the paper feed roller, and the cam piece when the piece is in said second rotation interval, the first elastic member is not preferably be brought close to the lifting plate to the paper feed roller.

  According to the above configuration, the first elastic member of the operating mechanism biases the lift plate toward the paper feed roller. On the other hand, the operating piece of the operating mechanism separates the lift plate from the paper feed roller. The cam piece of the control mechanism is rotatably attached to the housing. The cam piece is formed such that the rotation locus of the cam piece has a first rotation section in which the cam piece is interlocked with the operating piece and a second rotation section in which the interlock between the cam piece and the operating piece is released. When the cam piece is in the first rotation section, the operating piece interlocks with the cam piece and separates the lift plate from the paper feed roller. When the cam piece is in the second rotation section, the first elastic member causes the lift plate to approach the paper feed roller. Thus, the lift plate can be suitably separated from and in contact with the paper feed roller.

In the above configuration, the operating piece is a lever element including an arm portion that contacts the lift plate, a pin that contacts the peripheral surface of the cam piece, and a support shaft portion that is rotatably attached to the rotating unit. It is not preferred.

  According to the above configuration, the operating piece is a lever element. The pin of the lever element makes contact between the lever element and the cam piece by contacting the peripheral surface of the cam piece. The lever element rotates around the support shaft portion by contact between the pin and the peripheral surface of the cam piece. The arm portion of the lever element contacts the lift plate, and when the cam piece is in the first rotation section, the lift plate is separated from the paper feed roller in conjunction with the cam piece. Thus, the interlocking between the lever element and the cam piece is suitably achieved.

In the above configuration, the lift plate is in contact with the base end portion rotatably supported by the rotation unit and the arm portion, and is disposed at a position closer to the conveyance path than the base end portion. The support shaft portion is provided between the pin and the arm portion, and the pin is formed at a position farther from the transport path than the support shaft portion. It has preferred.

  According to the above configuration, when the rotation unit is rotated from the second position to the first position, the rotation of the pin around the support shaft portion is within the range in which the cam piece rotates the pin in the first rotation section. An actuating piece and a cam piece are arranged in As a result, when the rotating unit is returned from the second position to the first position, it is possible to suppress a force in a direction different from that during normal operation from being applied to the lever element, and it is easy to avoid damage to the lever element.

In the above configuration, the lock mechanism includes: a lock piece formed to be engageable with the lift plate; and a second elastic member that urges the lock piece toward a lock position to be engaged with the lift plate. And when the cam piece is in the second rotation section, the control mechanism moves the lock piece in a direction opposite to the biasing direction of the second elastic member, and between the lock piece and the lift plate. it preferred it to unlock.

  According to the above configuration, the second elastic member of the lock piece biases the lock piece toward the lock position that engages with the lift plate. Therefore, the 2nd elastic member can lock a lift board suitably using a lock piece. When the cam piece is in the second rotation section, the control mechanism moves the lock piece in a direction opposite to the urging direction of the second elastic member, and releases the lock between the lock piece and the lift plate. Thus, the lock between the lock piece and the lift plate is preferably released by the interlocking of the cam piece and the lock piece.

In the above-described configuration, the second elastic member biases the lock piece toward the control mechanism, the control mechanism includes a protruding portion that protrudes toward the lock piece, and the cam piece is the second piece. when in the rotating section, the protrusion is in contact with the lock piece, it has preferably be unlocked between the lift plate and the lock piece.

  According to the above configuration, the second elastic member biases the lock piece toward the control mechanism. When the cam piece is in the second rotation section, the protruding portion of the control mechanism that protrudes toward the lock piece comes into contact with the lock piece and releases the lock between the lock piece and the lift plate. Thus, the lock between the lock piece and the lift plate is preferably released by the interlocking of the cam piece and the lock piece.

In the above configuration, the control mechanism further includes a drive source for rotating the cam piece, the paper feed roller includes a gear, and when the rotating unit is in the first position, the drive source is the gear. It has preferred that transmits the driving force to the feed roller via the.

  According to the above configuration, the drive source that rotates the cam piece transmits the driving force to the paper feed roller via the gear of the paper feed roller when the rotation unit is in the first position. Thus, a drive source for operating the control mechanism can be used for operating the paper feed mechanism, and the number of components can be reduced, and the image forming apparatus can be reduced in size and weight.

  As described above, the present invention makes it easy to take out a jammed sheet on the downstream side of the paper feed mechanism, and allows the paper feed mechanism to be easily reinstalled after the sheet is removed.

1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an internal configuration of the image forming apparatus illustrated in FIG. 2. It is an expansion perspective view of the rotation unit in the 1st position. It is an expansion perspective view of the rotation unit in a 2nd position. It is a figure which shows roughly arrangement | positioning of a paper feed mechanism and a control mechanism. It is a figure which shows a paper feeding mechanism. It is a perspective view of a paper feed mechanism and a control mechanism. It is a figure explaining the interlocking of an operation mechanism and a control mechanism. It is a figure explaining the interlocking of an operation mechanism and a control mechanism. It is a figure explaining the interlocking of an operation mechanism and a control mechanism. It is a figure explaining the drive mechanism which transmits a drive force to a control mechanism and a paper feed roller. It is a figure explaining a locking mechanism. It is a figure explaining the interlocking of a control mechanism and a lock mechanism. It is a figure which shows the lock mechanism which cancel | released the lock | rock of the lift board.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that terms used in the following description, such as “up”, “down”, “left”, “right” and the like, are merely for the purpose of clarifying the explanation and do not limit the present invention. Not what you want. In the following description, the term “sheet” includes a sheet material that is subjected to an image forming process such as copy paper, coated paper, an OHP sheet, cardboard, postcard, and tracing paper. The terms “upstream”, “downstream” and similar terms used in the following description mean “upstream”, “downstream” and similar concepts in the sheet conveyance direction.

  FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 schematically shows the internal structure of the image forming apparatus shown in FIG. The image forming apparatus shown in FIGS. 1 and 2 is a so-called in-body discharge type copier, but in other embodiments, a printer, a facsimile machine, a multifunction machine having these functions, or a toner image on a sheet. Other devices for forming may be used.

  The image forming apparatus 1 includes a housing 2 having a substantially rectangular parallelepiped shape. The casing 2 includes a substantially rectangular parallelepiped lower casing 21, a substantially rectangular parallelepiped upper casing 22 disposed above the lower casing 21, and a connection that connects the lower casing 21 and the upper casing 22. And a housing 23. The connection housing 23 extends along the right edge and the back edge of the housing 2. The sheet subjected to the printing process is discharged into a discharge space 24 surrounded by the lower casing 21, the upper casing 22, and the connecting casing 23.

  The operation unit 221 protruding in the front direction of the upper housing 22 includes, for example, an LCD touch panel 222. The operation unit 221 is formed so as to be able to input information related to the image forming process. For example, the user can input the number of sheets to be printed, the print density, and the like through the LCD touch panel 222. Housed in the upper housing 22 are mainly an apparatus for reading an image of a document and an electronic circuit that controls the entire image forming apparatus 1.

  A pressing cover 223 disposed on the upper housing 22 is used for pressing the document. The presser cover 223 is attached to the upper housing 22 so as to be rotatable up and down. The user rotates the holding cover 223 upward to place the document on the upper housing 22. Thereafter, the user can operate the operation unit 221 to cause the device for reading the document disposed in the upper housing 22 to read the image of the document.

  The lower casing 21 accommodates a cassette 211 formed so as to accommodate sheets. The cassette 211 can be pulled out from the lower housing 21 in the front direction. The sheets stored in the cassette 211 are subjected to an image forming process in the lower housing 21 based on an instruction input by the user through the operation unit 221, and are discharged into the discharge space 24.

  A tray 212 is rotatably attached to the right surface of the lower housing 21. As shown in FIG. 1, when the tray 212 is in a position protruding to the right of the lower housing 21, the user can place a sheet on the tray 212. The sheet on the tray 212 is drawn into the lower housing 21 based on an instruction input by the user through the operation unit 221, is subjected to image forming processing, and is discharged into the discharge space 24. When the tray 212 is rotated upward, the tray 212 is accommodated in the accommodation space 213 that is recessed in the right surface of the lower casing 21, and the supply port for drawing the sheet into the lower casing 21 is closed.

  The lower housing 21 accommodates various devices for forming an image on a sheet. Further, the connection housing 23 accommodates various devices for discharging the sheet subjected to the image forming process to the discharge space 24.

  FIG. 2 schematically shows the internal structure of the image forming apparatus 1 shown in FIG. The image forming apparatus 1 will be further described with reference to FIG. 1 in conjunction with FIG.

The upper housing 22 accommodates the scanning mechanism 224. The user can cause the image forming apparatus 1 to read an image of a desired document through the scanning mechanism 224. A contact glass 225 attached to the upper surface of the upper housing 22 is disposed on the scanning mechanism 224. The pressing cover 223 is used for pressing a document placed on the contact glass 225.
And a pressing cover 162 that rotates on the contact glass 161. When the user operates the image forming apparatus 1 through the operation unit 221, the scanning mechanism 224 scans and reads an image of the document on the contact glass 225. Analog information of the image read by the scanning mechanism 224 is converted into a digital signal. The image forming apparatus 1 forms an image on a sheet based on the digital signal.

  The lower housing 21 accommodates toner containers 900Y, 900M, 900C, and 900K, an intermediate transfer unit 92, an image forming unit 93, an exposure unit 94, a fixing unit 97, and a paper discharge unit 96.

  The image forming unit 93 is used for forming an image on a sheet. The image forming unit 93 includes a yellow toner container 900Y, a magenta toner container 900M, a cyan toner container 900C, and a black toner container 900K. Below these containers, developing devices 10Y, 10M, 10C, and 10K corresponding to the respective colors of YMCK are disposed.

  The image forming unit 93 includes a photosensitive drum 17 (a photosensitive member on which a latent image is formed by an electrophotographic method) that carries a toner image of each color. As the photosensitive drum 17, a photosensitive drum using an amorphous silicon (a-Si) material can be used. The photosensitive drums 17 are supplied with yellow, magenta, cyan, and black toners from the toner containers 900Y, 900M, 900C, and 900K, respectively.

  Around the photosensitive drum 17, a charger 16, a developing device 10 (10Y, 10M, 10C, 10K), a transfer device (transfer roller) 19 and a cleaning device 18 are arranged. The charger 16 uniformly charges the surface of the photosensitive drum 17. The surface of the photosensitive drum 17 after charging is exposed by the exposure unit 94 to form an electrostatic latent image. The exposure unit 94 emits laser light based on the digital signal generated by the scanning mechanism 224 described above. The developing devices 10Y, 10M, 10C, and 10K develop the electrostatic latent images formed on the respective photosensitive drums 17 using the toners of the respective colors supplied from the toner containers 900Y, 900M, 900C, and 900K, respectively ( Visualization). The transfer roller 19 forms a nip portion with the photosensitive drum 17 across the intermediate transfer belt 921, and primarily transfers the toner image on the photosensitive drum 17 onto the intermediate transfer belt 921. The cleaning device 18 cleans the peripheral surface of the photosensitive drum 17 after the toner image is transferred.

  Each developing device 10Y, 10M, 10C, 10K includes a housing 20. A two-component developer having a magnetic carrier and toner is accommodated in the housing 20. In the housing 20, two agitating rollers 11 and 12 (developer agitating members) are rotatably arranged in parallel near the bottom of the housing 20 with the longitudinal direction as an axial direction.

  A developer circulation path is set on the inner bottom surface of the housing 20, and the stirring rollers 11 and 12 are disposed in the circulation path. A partition wall 201 erected from the bottom of the housing 20 is provided in the axial direction between the stirring rollers 11 and 12. The partition wall 201 divides the circulation path. A circulation path is formed so as to circulate around the partition wall 201. The two-component developer is charged while being stirred and conveyed on the circulation path by the stirring rollers 11 and 12.

  The two-component developer circulates in the housing 20 while being stirred by the stirring rollers 11 and 12, and the toner is charged. The two-component developer on the stirring roller 11 is attracted and conveyed by the magnetic roller 14 located on the upper side. The sucked two-component developer forms a magnetic brush (not shown) on the magnetic roller 14. The layer thickness of the magnetic brush is regulated by the doctor blade 13. The toner layer on the developing roller 15 is formed by a potential difference between the magnetic roller 14 and the developing roller 15. The electrostatic latent image on the photosensitive drum 17 is developed by the toner layer.

  The exposure unit 94 includes various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror. Light based on image data is provided on the peripheral surface of the photosensitive drum 17 provided in each of the image forming units 93. To form an electrostatic latent image.

  The intermediate transfer unit 92 includes an intermediate transfer belt 921, a driving roller 922, and a driven roller 923. On the intermediate transfer belt 921, toner images are overcoated from a plurality of photosensitive drums 17 (primary transfer). The overcoated toner image is secondarily transferred to a sheet supplied from the cassette 211 or the tray 212 (see FIG. 1) in the secondary transfer unit 98. A driving roller 922 and a driven roller 923 that rotate the intermediate transfer belt 921 are rotatably supported by the lower housing 21.

  The fixing unit 97 performs a fixing process on the toner image on the sheet secondarily transferred from the intermediate transfer unit 92. The sheet with the color image that has been subjected to the fixing process is discharged toward a paper discharge unit 96 formed in the upper part of the fixing unit 97 (in the connection housing 23).

  The paper discharge unit 96 discharges the sheet conveyed from the fixing unit 97 onto the upper surface 213 of the lower housing 21 used as a paper discharge tray.

  The cassette 211 stores a sheet bundle formed by stacking a plurality of sheets on which images are formed. As described above, the cassette 211 is detachably attached to the lower housing 21. When the pickup roller 40 provided in the cassette 211 is driven, the uppermost sheet of the sheet bundle in the cassette 211 is taken out one by one, fed out to the paper feed conveyance path 133, and introduced into the image forming unit 93. The

  The tray 212 is disposed above the cassette 211. The tray 212 shown in FIG. 2 is in a closed position for closing the paper feed port. The lower end portion of the tray 212 serves as a rotation shaft, and the tray 212 is rotated rightward so that a sheet bundle formed by stacking a plurality of sheets can be supported. A paper feed mechanism 500 is disposed near the lower end of the tray 212.

  A conveyance path 600 extending from the downstream side of the paper feeding mechanism 500 to the secondary transfer unit 98 of the image forming unit 93 is formed. The conveyance path 600 is formed between an inner wall portion 610 formed in the housing 2 and a conveyance wall 621 that forms the inner surface of the rotation unit 620. The sheet feeding mechanism 500 is used for feeding sheets on the tray 212 to the conveyance path 600.

  As shown in FIG. 1, the outer surface of the rotation unit 620 forms part of the right surface of the lower housing 21 and the connection housing 23. A lower end portion of the rotation unit 620 is rotatably attached to the lower housing 21. A knob 622 is formed adjacent to the upper edge of the outer surface of the rotation unit 620. The user operates the knob 622 to rotate the rotation unit 620 downward to expose the inner wall portion 610 of the housing 2 forming the conveyance path 600 and the conveyance wall 621 of the rotation unit 620 to the outside. be able to. The paper feed mechanism 500 described above is attached to the rotation unit 620 and rotates together with the rotation unit 620.

  FIG. 3 is an enlarged perspective view showing the rotation unit 620 in the first position. When the rotation unit 620 is in the first position, as shown in FIG. 2, the conveyance wall 621 of the rotation unit 620 is close to the inner wall portion 610 of the housing 2, and the conveyance path 600 is formed. FIG. 4 is an enlarged perspective view showing the rotation unit 620 in the second position. When the rotation unit 620 is in the second position, the transport wall 621 is separated from the inner wall portion 610 of the housing 2, and the inner wall 610 and the transport wall 621 forming the transport path 600 are exposed to the outside. FIG. 5 schematically shows the position of the sheet feeding mechanism 500 and the control mechanism for controlling the operation of the sheet feeding mechanism 500 when the rotation unit 620 is in the second position. The rotation unit 620, the paper feed mechanism 500, and the control mechanism will be described with reference to FIGS.

  As described above, the rotation unit 620 includes the rotation shaft 623 attached to the inner surfaces of the front wall 25 and the rear wall 26 of the housing 2. The rotation shaft 623 is positioned at the lower end of the rotation unit 620 when the rotation unit 620 is in the first position, and is positioned at the left end of the rotation unit 620 when the rotation unit 620 is in the second position. The rotation unit 620 rotates up and down around the rotation shaft 623 and moves between the first position and the second position.

  The paper feed mechanism 500 is provided in the rotation unit 620. The control mechanism 700 is provided in the housing 2 of the image forming apparatus 1. As described above, the tray 212 is rotatably attached to the outer surface of the rotation unit 620. The lower end of the tray 212 is provided below the rotation unit 620, and the tray 212 rotates around the lower end. When the tray 212 is rotated so as to protrude from the rotation unit 620, a conveyance path that connects the lower end portion of the tray 212 to the sheet feeding mechanism 500 is opened. The control mechanism 700 is attached to the lower part of the inner surface of the back wall 26 that forms a space for accommodating the rotation unit 620 in the first position. When the rotation unit 620 is in the first position, the control mechanism 700 is connected to the paper feed mechanism 500 and controls the operation of the paper feed mechanism 500.

  FIG. 6 schematically shows the paper feed mechanism 500. The sheet feeding mechanism 500 partially rotates the sheet feeding roller 510 that feeds the sheet placed on the tray 212 to the conveyance path 600, and partially supports the sheet on the tray 212 and is separated from the sheet feeding roller 510. The lift plate 520 is formed in a possible manner, and the separation pad 539 is disposed on the downstream side of the lift plate 520 and pressed against the peripheral surface of the paper feed roller 510.

  A base end portion of the lift plate 520 located inside the housing 2 is rotatably supported inside the rotation unit 620. With the base end portion of the lift plate 520 as an axis, the tip end portion of the lift plate 520 (the end portion closer to the conveyance path 600 than the base end portion) rotates up and down. When the sheet on the tray 212 is fed into the housing 2, the tip of the lift plate 520 causes the sheet to approach the paper feed roller 510. The sheet in contact with the sheet feed roller 510 is guided to the downstream conveyance path 600 as the sheet feed roller 510 rotates. The separation pad 539 generates a frictional force on the lower surface of the sheet fed by the paper feed roller 510. As a result, when the sheet feeding roller 510 attempts to convey a plurality of sheets downstream, the separation pad 539 removes the uppermost sheet (a sheet that directly contacts the sheet feeding roller 510) to the conveying path 600. Hindering the transport. As a result, the sheets are sent out to the conveyance path 600 one by one.

  FIG. 7 is a perspective view of the paper feed mechanism 500 and the control mechanism 700. FIG. 8 shows the lift plate 520 in a position close to the paper feed roller 510. FIG. 9 shows the lift plate 520 at a position spaced from the paper feed roller 510. The operation of the lift plate 520 will be further described with reference to FIGS. 5 and 6 in conjunction with FIGS. 7 to 9, the walls, brackets, and frames for supporting the elements of the paper feed mechanism 500 and the elements of the control mechanism 700 are omitted to avoid unnecessarily obscuring the drawings. Yes. Therefore, each component of the paper feed mechanism 500 is attached to a wall portion forming the casing of the rotation unit 620 or the paper feed mechanism 500, a bracket or a frame attached to the casing of the rotation unit 620 or the paper feed mechanism 500. It should be interpreted as being properly supported. Each component of the control mechanism 700 should be interpreted as being appropriately supported by the inner wall surface of the housing 2 of the image forming apparatus 1 or a bracket or frame attached to the inner wall surface.

  The paper feed mechanism 500 includes an operation mechanism 530 for bringing the lift plate 520 into and out of contact with the paper feed roller 510. The operating mechanism 530 includes a first elastic portion including a proximal end portion connected to the bottom portion of the housing 540 of the paper feeding mechanism 500 disposed in the rotation unit 620 and a distal end portion connected to the lower surface of the lift plate 520. A member (for example, a coil spring) 531 and an operating piece 532 that contacts the lift plate 520 and moves the lift plate 520 downward are included.

  The first elastic member 531 biases the lift plate 520 toward the paper feed roller 510. The lift plate 520 includes a protrusion 521 that protrudes from the side edge of the lift plate 520 toward the back wall 26 of the housing 2 of the image forming apparatus 1 to which the control mechanism 700 is attached. The protrusion 521 is formed at the tip of the lift plate 520 that is separated from the tray 212. The upper surface of the protruding portion 521 is brought into contact with the operating piece 532 and is pushed downward along with the rotational movement of the operating piece 532 due to the interference between the arm portion 534 and the protruding portion 521.

  In the present embodiment, the operating piece 532 is formed as a lever element. However, in another embodiment, any structure or element that can push down the lift plate 520 in conjunction with the control mechanism 700 is used as the operating piece 532. May be used. The operating piece 532 is a substantially L-shaped element, and a substantially annular support shaft portion 533 is formed at a bent portion of the operating piece 532. The support shaft portion 533 is rotatably supported by, for example, a housing 540 of the paper feed mechanism 500, a wall portion of the rotation unit 620, a shaft formed on a bracket or a frame. The operating piece 532 further includes a rod-shaped arm portion 534 extending from the support shaft portion 533 toward the downstream side. The arm portion 534 is in contact with the upper surface of the protruding portion 521 of the lift plate 520. The operating piece 532 further includes a holding plate 535 extending obliquely downward from the support shaft portion 533 toward the upstream, and a pin 536 protruding from the holding plate 535 toward the back wall 26 to which the control mechanism 700 is attached. The pin 536 is formed on the tray 212 side (that is, a position separated from the conveyance path 600) from the support shaft portion 533. The pin 536 rotatably attached to the holding plate 535 is used to contact the control mechanism 700 attached to the back wall 26 and rotate the operation piece 532 in conjunction with the control mechanism 700.

  The control mechanism 700 includes a control piece 710. The control piece 710 includes an annular support shaft portion 711 and a cam piece 712 having a curved contour protruding from the support shaft portion 711. The support shaft 711 is rotatably supported by, for example, a shaft formed on the back wall 26 of the housing 2 of the image forming apparatus 1.

  As shown in FIGS. 8 and 9, when the control piece 710 rotates around the support shaft portion 711 (in FIG. 8 and FIG. 9, the control piece 710 rotates clockwise), the circumferential surface of the cam piece 712 Contacts the peripheral surface of the pin 536 and applies an upward force to the pin 536. As a result, the operating piece 532 rotates around the support shaft portion 533 formed between the arm portion 534 and the pin 536. The arm portion 534 extending from the support shaft portion 533 moves downward as the operation piece 532 rotates. As a result, the arm portion 534 interferes with the protruding portion 521 of the lift plate 520, the tip end portion of the lift plate 520 is pushed downward, and the lift plate 520 is separated from the paper feed roller 510.

  FIG. 10 shows the control piece 710 further rotated. The interlocking between the control mechanism 700 and the operation mechanism 530 will be further described with reference to FIGS. 8 and 9 in conjunction with FIG.

  The peripheral contour of the cam piece 712 is formed so that the contact between the cam piece 712 and the pin 536 is released at a position where the lift plate 520 is sufficiently separated from the paper feed roller 510. Accordingly, the rotation locus of the cam piece 712 is in contact with the pin 536, the first rotation section in which the operating piece 532 is interlocked with the cam piece 712, and the second interlocking state between the operating piece 532 and the cam piece 712 is released. The rotation section is included. The cam piece 712 shown in FIGS. 8 and 9 is in the first rotation section, and the cam piece 712 shown in FIG. 10 is in the second rotation section. As described above, when the cam piece 712 is in the first rotation section, the operating piece 532 separates the lift plate 520 from the paper feed roller 510.

  When the cam piece 712 is in the second rotation section, the cam piece 712 is separated from the pin 536. Accordingly, the upward force generated on the pin 536 disappears. On the other hand, the lift plate 520 rotated downward by the arm portion 534 sufficiently compresses the first elastic member 531. The sufficiently compressed first elastic member 531 pushes the lift plate 520 upward. As a result, when the cam piece 712 is in the second rotation section, the lift plate 520 approaches the paper feed roller 520. Thus, the operating mechanism 530 moves the lift plate 520 to and away from the paper feed roller 510 in conjunction with the control mechanism 700.

  FIG. 11 shows a drive mechanism for the control mechanism 700 and the paper feed roller 510. The driving of the control mechanism 700 and the paper feed roller 510 will be described with reference to FIG. 7 in conjunction with FIG.

  The paper feed roller 510 includes a shaft 511, a cylindrical roller portion 512 that protrudes radially from the outer peripheral surface of the shaft 511 and rotates integrally with the shaft 511, and a base end portion of the shaft 511 (of the image forming apparatus 1. Gear 513 attached to the rear wall 26 side end). The control piece 710 is attached coaxially with a gear 750 disposed below the gear 513. A gear 750 connected to a drive source (not shown) such as a motor rotates under the control of a solenoid switch 753. The control piece 710 rotates integrally with the rotation of the gear 750. A gear 513 is disposed on the rotation shaft of the gear 750, and the output gear 752 meshes with the gear 513. Accordingly, the paper feed roller 510 rotates as the output gear 513 rotates. As shown in FIG. 11, the gear 750 includes a non-engagement portion 751 in which gear teeth are not formed and an engagement portion 752 in which gear teeth for meshing with the gear 513 are formed. The non-meshing portion 751 and the meshing portion 752 rotate when the lift plate 520 comes close to the paper feed roller 510 and rotates when the lift plate 520 is separated from the paper feed roller 510. Not formed. When the rotation unit 620 is in the first position, the gear 513 of the paper feed roller 510 is disposed at a position where it can mesh with the gear 750.

  Refer to FIG. 7 again. As shown in FIG. 7, the paper feed mechanism 500 further includes a lock mechanism 550 disposed below the operation piece 532. The lock mechanism 550 interlocks with the control mechanism 700 to lock and unlock the lift plate 520.

  FIG. 12 is a cross-sectional view showing the lock mechanism 550. The locking mechanism 550 is further described with reference to FIG. 7 in conjunction with FIG.

  The lock mechanism 550 includes a lock piece 551 formed in a substantially rectangular parallelepiped shape, and a second elastic member (for example, a coil spring) 552 that biases the lock piece 551 toward the control piece 710. By the second elastic member 552, the end surface 553 of the lock piece 551 is pressed against the inner surface 714 of the control piece 710 (the surface facing the paper feed mechanism 500).

  An engagement hole 522 is formed at the side end of the lift plate 520. The lock piece 551 includes an engagement portion 554 that extends upward and is inserted into the engagement hole 522. A hook portion 555 having a substantially triangular prism shape that protrudes toward the control piece 710 is formed at the tip of the engaging portion 554. The hook portion 55 engages with a lift plate 520 located at a position separated from the paper feed roller 510. As a result, the lift plate 520 is locked at a position away from the paper feed roller 510. The lift plate 520 shown in FIG. 12 is located away from the paper feed roller 510 and is locked by the hook portion 555. The position of the lock piece 551 shown in FIG. 12 is referred to as a lock position for convenience. The second elastic member 552 biases the lock piece 551 toward the lock position.

  FIG. 13 is a perspective view showing the shape of the control piece 710 on the inner surface 714 side. The operation of the locking mechanism 550 will be described with reference to FIGS. 7 and 12 in conjunction with FIG.

  The inner surface 714 of the control piece 710 includes a protrusion 715 that protrudes toward the lock piece 551. An inclined surface 556 is formed at the corner on the downstream side of the end surface 553 of the lock piece 551. When the control piece 710 rotates, the protrusion 715 contacts the inclined surface 556. Due to the contact between the inclined surface 556 and the projecting portion 715, the lock piece 553 moves in the direction opposite to the biasing direction of the second elastic member 552.

  FIG. 14 is a cross-sectional view showing the lock piece 551 that has been moved in the direction opposite to the urging direction of the second elastic member 552 by contact with the protrusion 715. The interlocking between the lock piece 551 and the control piece 710 will be described with reference to FIGS. 7, 12, and 13 in conjunction with FIG.

  When the lock piece 551 is moved in the direction opposite to the urging direction of the second elastic member 552 by contact with the projecting portion 715, the lock of the lift plate 520 by the hook portion 555 is released. At this time, the lift plate 520 can move upward. As described above, the lift plate 520 rotates toward the paper feed roller 510 when the cam piece 712 is in the second rotation section. Accordingly, the protruding portion 715 and / or the lock piece 551 of the control piece 710 is not in the release position (the position of the lock piece where the hook 555 does not interfere with the lift plate 520) while the cam plate 712 is in the second rotation section. ) To keep. As a result, while the cam plate 712 is in the second rotation section, the lock between the lock piece 551 and the lift plate 520 is released.

  As schematically shown in FIG. 5, when the rotation unit 620 is in the second position, the paper feed mechanism 500 including the operation mechanism 530 and the lock mechanism 550 is separated from the control mechanism 700. As a result, a first elastic member 531 (see, for example, FIG. 8) disposed below the lift plate 520 applies a force to the lift plate 520 in a direction approaching the paper feed roller 510. However, since the connection between the lock mechanism 550 and the control mechanism 700 is also released at the same time, the second elastic member 552 (for example, see FIG. 12) moves the lock piece 551 to the lock position. As a result, when the rotation unit 620 is in the second position, the lift plate 520 is locked and can be kept away from the paper feed roller 510. For this reason, it becomes easy to insert the leading edge of the sheet between the lift plate 520 and the paper feed roller 510. Therefore, for example, in order to remove the jammed sheet in the conveyance path 600 (see FIG. 2), the print preparation work after the rotation unit 620 is moved toward the second position is relatively easily performed. It becomes.

  As described above, the pin 536 is disposed closer to the tray 212 than the support shaft portion 533 (that is, a position farther from the conveyance path 600 than the support shaft portion 533). Further, the positional relationship of the control piece 710 including the operating piece 532 and the cam piece 712 is such that when the turning unit 620 is turned from the second position to the first position, the cam piece 712 is pin 536 in the first rotation section. Is determined so that the rotation of the pin 536 around the support shaft portion 533 is within the range of rotation of the shaft 533. Therefore, even when the rotation unit 620 is returned to the first position, the control piece 710 receives a force that moves in the same direction as during normal operation (the operation described in connection with FIGS. 7 to 14). Abnormal force (force in the direction opposite to that during normal operation) does not act on the operating piece 532, and damage to the operating piece 532 is suppressed.

  The present invention can be applied to a printer, a copier, a facsimile machine, a multifunction machine having these functions, and various apparatuses for forming an image on a sheet.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Housing 500 ... Paper feed mechanism 510 ... Paper feed roller 513 ... Gear 520 ... Lift plate 530 ... Actuation mechanism 531 ..First elastic member 532... Operation piece 533... Support shaft portion 534... Arm portion 536... Pin 550... Lock mechanism 551. 600 ... conveying path 610 ... inner wall 620 ... rotating unit 621 ... conveying wall 700 ... control mechanism 712 ... cam piece 715 ... projecting portion 93 ... image formation Part

Claims (7)

A housing that houses an image forming unit for forming an image on a sheet;
A conveyance wall that forms a conveyance path extending to the image forming unit in cooperation with an inner wall formed inside the housing; and the conveyance wall is adjacent to the inner wall to form the conveyance path. A rotation unit attached to the housing so as to be rotatable between a first position and a second position where the transfer wall is separated from the inner wall;
A paper feed mechanism attached to the rotating unit and for feeding the sheet to the transport path;
A control mechanism that is attached to the housing and is connected to the paper feed mechanism when the rotating unit is in the first position, and controls the operation of the paper feed mechanism;
A drive mechanism for driving the paper feed mechanism and the control mechanism;
A drive control unit for controlling the drive of the drive mechanism ,
The paper feed mechanism includes a paper feed roller that rotates to send the sheet to the transport path;
A lift plate that supports the sheet at least partially and is attached to the rotating unit so as to be detachable from the paper feed roller;
In conjunction with the control mechanism, an actuation mechanism formed to bring the lift plate into and out of contact with the paper feed roller;
A lock mechanism that locks the lift plate at a position spaced from the paper feed roller and unlocks the lift plate in conjunction with the control mechanism;
The drive control unit when the rotation unit is in the second position, by the drive mechanism, the control mechanism is driven, while the cause releasing the interlocking between said actuation mechanism and the control mechanism, An image forming apparatus, wherein the lock mechanism is driven to lock the lift plate at a position separated from the paper feed roller. The operating mechanism includes a first elastic member that urges the lift plate toward the paper feed roller, and an operating piece that separates the lift plate from the paper feed roller,
The control mechanism includes a cam piece rotatably attached to the housing,
The cam piece has a rotation locus of the cam piece having a first rotation section in which the cam piece is interlocked with the operating piece and a second rotation section in which the interlock between the cam piece and the operating piece is released. Is formed
When the cam piece is in the first rotation section, the operating piece separates the lift plate from the paper feed roller;
The image forming apparatus according to claim 1, wherein when the cam piece is in the second rotation section, the first elastic member causes the lift plate to approach the paper feed roller.   The operating piece is a lever element including an arm portion that contacts the lift plate, a pin that contacts a peripheral surface of the cam piece, and a support shaft portion that is rotatably attached to the rotating unit. The image forming apparatus according to claim 2. The lift plate is in contact with the arm portion and a base end portion that is rotatably supported by the rotation unit, and is disposed at a position closer to the transport path than the base end portion. Including
The support shaft portion is provided between the pin and the arm portion,
The image forming apparatus according to claim 3, wherein the pin is formed at a position farther from the conveyance path than the support shaft portion. The lock mechanism includes a lock piece formed to be engageable with the lift plate, and a second elastic member that biases the lock piece toward a lock position to be engaged with the lift plate,
When the cam piece is in the second rotation section, the control mechanism moves the lock piece in a direction opposite to the urging direction of the second elastic member, and locks between the lock piece and the lift plate. 5. The image forming apparatus according to claim 2, wherein the image forming apparatus is released. The second elastic member biases the lock piece toward the control mechanism,
The control mechanism includes a protrusion that protrudes toward the lock piece,
6. The image according to claim 5, wherein when the cam piece is in the second rotation section, the protrusion comes into contact with the lock piece and releases the lock between the lock piece and the lift plate. Forming equipment. The control mechanism further includes a drive source for rotating the cam piece,
The paper feed roller includes a gear;
The image according to any one of claims 2 to 6, wherein when the rotating unit is in the first position, the driving source transmits a driving force to the paper feeding roller via the gear. Forming equipment.

Images