The present invention relates to a sheet stacking device in which sheets are stacked, an image forming device including the sheet stacking device, and a regulation member.
Image forming devices such as printers stack and house sheets in sheet stacking devices such as sheet feed cassettes, convey the sheets one by one to a conveyance path, and form an image on each of the sheets.
Such a sheet stacking device includes a regulation member that contacts, when a sheet is housed in the sheet stacking device, an upstream end of the sheet in a conveyance direction (rear end in the conveyance direction) or a lateral end of the sheet in a width direction orthogonal to the conveyance direction and thereby regulates a position of the sheet upstream in the conveyance direction or in the width direction.
In many structures, the regulation member is supported so that the regulation member is movable in the conveyance direction (or the width direction) of sheets. For example, when replacing sheets of A4 size with sheets of B5 size, a user can move the regulation member from a regulation position corresponding to the A4 size to a regulation position corresponding to the B5 size. This structure makes the sheet stacking device compatible with sheets of different sizes.
When the regulation member is moved by a user to a regulation position corresponding to the size of the sheets, the regulation member is locked so that the regulation member does not move from the regulation position. Japanese Patent Application Publication No. 2010-6596 discloses, as such a locking mechanism, a structure in which a stopper of the regulation member is engaged with a rack unit at a bottom surface of the sheet stacking device. In order to maintain such an engagement, a restoring force of a spring is utilized. Unlocking of the regulation member is achieved by a user pushing a release lever in a travel direction of the regulation member with a force greater than the restoring force of the spring.
According to the structure disclosed by Japanese Patent Application Publication No. 2010-6596, in order to unlock the regulation member and move the regulation member to another regulation position, a user has to apply to the regulation member a force greater than the restoring force of the spring that maintains the engagement of the regulation member and continue to push the regulation member to maintain unlocking of the regulation member.
Continuing to apply a great force to the regulation member is a burden for a user. Further, when an amount of the force applied to the regulation member by the user is insufficient, the user may fail to stop the regulation member at a desired regulation position. Also, when the force applied to the regulation member by the user is too great, the regulation member may be pushed into the sheets while the regulation member is in contact with the sheets, which may result in damaging the sheets.
Problems as described above are not limited to sheet feed cassettes of image forming devices, and may occur in any sheet stacking device including a regulation member regulating a position of a sheet in the sheet stacking device.
An object of the present invention is to provide a sheet stacking device whose regulation member is manipulated by a user with ease, an image forming device including such a sheet stacking device, and a regulation member.
To achieve at least one of the abovementioned objects, a sheet stacking device reflecting one aspect of the present invention includes: a stacking unit in which a sheet is stacked; and a regulation member that is movably supported by the stacking unit and is brought into contact with an edge of the sheet to regulate a position of the sheet. In the sheet stacking device, the regulation member includes: a locking member that is movable between an engagement position and a disengagement position, the engagement position being a position at which the locking member is engaged with an engaging portion of the stacking unit, and the disengagement position being a position at which the locking member is disengaged from the engaging portion; a biasing member that biases the locking member toward the engagement position; a force receiver that receives a user operation; a releaser that converts a first force in a first direction applied to the force receiver by a user operation into a second force in a second direction opposing a biasing force from the biasing member and being applied to the locking member, moving the locking member from the engagement position to the disengagement position; and a stopper that, after the locking member disengages from the engaging portion and a user operation is not applied to the force receiver, prevents a movement of the locking member back to the engagement position due to the biasing force from the biasing member.
The advantages and features provided by one or more embodiments of the invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the invention.
In the drawings:
Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments.
The following describes an embodiment of a sheet stacking device, an image forming device, and a regulation member pertaining to the present invention, taking a tandem-type color printer (hereinafter referred to as “printer”) as an example.
As illustrated in
The image forming units 1Y, 1M, IC, and 1K are arrayed in parallel directly below the intermediate transfer belt 2 along a travel direction of the intermediate transfer belt 2.
The image forming unit 1Y forms a toner image of the Y color on a photoreceptor drum 6 that rotates in a direction indicated by an arrow in
The sheet feed unit 3 includes components such as a sheet feed cassette 31, a pickup roller 32, conveyance rollers 33, and timing rollers 34.
The sheet feed cassette 31 is a sheet stacking device for stacking and housing sheets S as recording sheets, and is supported by a device main body 9 so that the sheet feed cassette 31 can be pulled out toward a device front side relative to the device main body 9. When supplying a sheet S into the sheet feed cassette 31, a user pulls out the sheet feed cassette 31 toward the device front side, puts a new sheet S into the sheet feed cassette 31, and pushes back the sheet feed cassette 31 toward a device back side so that the sheet feed cassette 31 is in its original sheet feed position.
The pickup roller 32 picks up a sheet S from the sheet feed cassette 31 and feeds the sheet S to a conveyance path 30. The conveyance rollers 33 convey the sheet S downstream in a conveyance direction.
The timing rollers 34 are driven according to a timing at which the sheet S conveyed by the conveyance rollers 33 is conveyed to secondary transfer rollers 2a.
The fixing unit 4 includes a fixing roller and a pressure roller that fix the toner images by heating and pressurizing the sheet S at a predetermined fixing temperature.
The control unit 5 causes, on the basis of image data from the external terminal device, the image forming units 1Y, 1M, IC, and 1K to respectively form toner images on the corresponding photoreceptor drums 6.
The toner images on the photoreceptor drums 6 are transferred onto the intermediate transfer belt 2 (primary transfer). Here, each of the toner images is transferred at a different timing so that the toner images are transferred onto the same position of the intermediate transfer belt 2.
The toner images that are transferred onto the same position of the intermediate transfer belt 2 move, through a circular travel of the intermediate transfer belt 2, to a secondary transfer position 2b at which the secondary transfer rollers 2a are pressed onto the intermediate transfer belt 2.
In accordance with the image forming timing described above, the sheet S is conveyed from the timing rollers 34 of the sheet feed unit 3. The sheet S is conveyed while being sandwiched between the intermediate transfer belt 2, which travels in circulation, and the secondary transfer rollers 2a. The toner images on the intermediate transfer belt 2 are then transferred all at once onto the sheet S at the secondary transfer position 2b (secondary transfer).
After passing through the secondary transfer position 2b, the sheet S is conveyed to the fixing unit 4, and the toner image is fixed to the sheet S through heat and pressure at the fixing unit 4. The sheet S is then ejected by ejection rollers 35 and is stored in a storage tray 36.
As illustrated in
The side walls 11 include a front side wall 11a at the device front side, a right side wall 11b, a left side wall 11c, and a back side wall 11d. The front side wall 11a has a cover 11e attached thereto. The cover 11e has a handle 11f that a user holds when the user pulls out the sheet feed cassette 31 to the device front side or when the user pushes the sheet feed cassette 31 into the device back side.
A guiding region 16 is arranged at the bottom surface 10. The guiding region 16 extends in the sheet feed direction (direction of arrow A) of sheets S, and a rear end regulation plate 15 is arranged so as to be slidable along the guiding region 16. The rear end regulation plate 15 regulates, in accordance with the size (such as A4 and B5) of sheets S stacked onto the bottom surface 10, a position of an edge (sheet rear end) of the sheets S in a sheet rear end direction (direction of arrow B).
A push-up plate 12 is disposed on the bottom surface 10, at a front of the bottom surface 10 in the sheet feed direction. When the sheet feed cassette 31 is at the sheet feed position (that is, when the sheet feed cassette 31 is pushed into the device main body 9), the push-up plate 12 pushes up, from the bottom surface 10, a portion at a front in the sheet feed direction of the sheets S stacked and housed in the sheet feed cassette 31, and pushes an uppermost sheet S onto the pickup roller 32. In this state, a rotation of the pickup roller 32 causes the uppermost sheet S to be fed to the conveyance path 30.
Side regulation plates 13 and 14 that are spaced away from each other in the Y-axis direction are disposed between the front side wall 11a and the back side wall 11d. The side regulation plates 13 and 14 are supported by guiding grooves (not illustrated) arranged at the bottom surface 10 and extending in the Y-axis direction, so that the side regulation plates 13 and 14 are slidable on the bottom surface 10 in the Y-axis direction. The side regulation plates 13 and 14 regulate positions of edges (sheet side ends) of the sheets S in the Y-axis direction (sheet width direction) in accordance with a size of sheets S stacked on the bottom surface 10.
As illustrated in
The low-floor portion 16a and the groove portion 16b extend in the sheet feed direction.
Each pair of the recesses 16c corresponds to a different one of lengths in the sheet feed direction of sheets S having different sizes. The rear end regulation plate 15 includes a lever 54 having protrusions 54c and a lever 55 having protrusions 55c (
As illustrated in
The base 51 is a plate-like member having a substantially trapezoidal shape, and a guiding member 51a protruding in a downward direction is arranged at a lower surface of the base 51. A projecting portion 51b extending from the guiding member 51a in a direction orthogonal to the downward direction is arranged at a leading end of the guiding member 51a.
During assembly, the guiding member 51a of the base 51 is inserted from an opening 16f (
The body 52 is at an end of the base 51 in the sheet rear end direction, and has two walls 52a protruding at ends of the body 52 in the Y-axis direction and having a gap between each other in the Y-axis direction, and an upper body portion 52b connecting upper ends of the walls 52a.
The operation member 53 receives from a user a locking operation for establishing locking of the rear end regulation plate 15 at a regulation position at the sheet rear end and an unlocking operation for releasing the locking.
As illustrated in
The receiving portion 53a receives a force that the user applies by pushing down the operation member 53. The receiving portion 53a has, at each end of the receiving portion 53a in the Y-axis direction, a ridge portion 53c and a tapered portion 53d. The ridge portion 53c is elongated in the Z-axis direction. The tapered portions 53d each taper so that the length of the receiving portion 53a in the Y-axis direction is shorter toward a lower end of the receiving portion 53a, and each have a tapered surface continuing from a lower end of the ridge portion 53c.
The upper body portion 52b has a cut-out portion 52c. At each end of the cut-out portion 52c in the Y-axis direction is a guiding groove 52p elongated in the Z-axis direction. The ridge portions 53c fit into the guide grooves 52p and are supported so that the ridge portions 53c are movable in the Z-axis direction along the guiding grooves 52p.
The guiding portion 53b has a shorter length in the Y-axis direction and a smaller thickness than the receiving portion 53a. Each side end 53e of the guiding portion 53b in the Y-axis direction is supported by a guiding member 52e so that each side end 53e is movable in the Z-axis direction. The guiding members 52e are elongated in the Z-axis direction and are located below the cut-out portion 52c of the upper body portion 52b. Consequently, the operation member 53 is movable in the Z-axis direction relative to the upper body portion 52b.
The guiding portion 53b has a guiding groove arrangement portion 53f and a spring holding portion 53g arrayed in the Y-axis direction. The guiding groove arrangement portion 53f has a main surface where a guiding groove 53h is arranged. The guiding groove 53h has a Y-shape in front view from the X-axis direction. The spring holding portion 53g has a projecting portion 53i projecting downward.
The guiding groove 53h is a bottomed groove engaged with a guiding rod 58. As described below, the guiding groove 53g has portions with different depths, and the narrowest portion of the guiding groove 53h has a width of, for example, about 0.8 mm.
The guiding rod 58 is made of a metal material such as a piano wire or a drawn steel wire having a small diameter (for example, 0.5 mm), and has a straight portion, a bent portion 58a at an upper end of the straight portion, and a bent portion 58b at a lower end of the straight portion. The bent portions 58a and 58b are formed by bending the metal material at a right angle.
The bent portion (engagement projection) 58a of the guiding rod 58 fits into the guiding groove 53h, and has a length greater than the depth of the deepest portion of the guiding groove 53h. The bent portion 58b of the guiding rod 58 fits into and is fixed to a recess 52f at a lower end of the upper body portion 52b. Because the bent portion 58b of the guiding rod 58 is fixed to the recess 52f, the guiding rod 58 is fixed to the upper body portion 52b.
The guiding rod 58 is biased by a biasing force from the leaf spring 59 so that the bent portion 58a is always in contact with the bottom surface of the guiding groove 53h. The leaf spring 59 has two protrusions 59a at its lower end. The protrusions 59a fit into and are fixed to two recesses 52g at the lower end of the upper body portion 52b. The leaf spring 59 further has an upper end 59b that applies the biasing force to the bent portion 58a in a direction in which the bent portion 58a is pressed onto the bottom surface of the guiding groove 53h.
The groove 71 is elongated in the Z-axis direction, and is located at a position lower than the other grooves 72 through 77. As illustrated in
The groove 72 extends obliquely left and upward from an upper end of the groove 71. The bottom surface 79 of the groove 72 slopes so that the bottom surface 79 of the groove 72 has a depth smaller than the reference depth toward an upper end of the groove 72.
The groove 73 extends upward from the upper end of the groove 72. The groove 72 connects to the groove 73 at a level difference 81, and the upper end of the groove 72 inclines so that the level difference 81 is not parallel to the Y-axis direction but has a right end lower than the left end. Due to the level difference 81, the bottom surface 79 of the groove 73 has a depth greater than the bottom surface 79 at the upper end of the groove 72.
The groove 74 extends from a branching position 73a at a lower end of the groove 73, and forms an inclining groove portion inclining at an acute angle from a direction extending from upward to downward, that is, a direction along the groove 72 away from the branching portion 73a (third direction).
The groove 75 has a V-shape in front view. A left upper end of the groove 75 connects to a terminal end of the groove 74 at a level difference 82, and forms a bending groove portion that bends in a direction away from the third direction relative to the terminal end of the groove 74. Because of the level difference 82, the bottom surface 79 of the groove 75 has a depth greater than the bottom surface 79 of the groove 74. When regarding the grooves 71, 72, and 73 as a single groove (first groove) extending in the Z-axis direction and the grooves 74 and 75 as another groove (second groove), the second groove can be regarded as a branching groove branching from the first groove at the branching position 73a.
The groove 75 has a right upper end connecting to a lower end of the groove 76 at a level difference 83. Because of the level difference 83, the bottom surface 79 of the groove 76 has a depth greater than the bottom surface 79 of the groove 75.
The groove 76 extends upward from its lower end, to which the right upper end of the groove 75 connects at the level difference 83.
The groove 77 extends obliquely left and downward from a lower end of the groove 76. The bottom surface 79 of the groove 77 slopes so that the bottom surface 79 of the groove 77 has a depth smaller than the bottom surface 79 of the groove 76 toward a lower end of the groove 77. The bottom surface 79 at the lower end of the groove 77 has a depth smaller than the reference depth, and the lower end of the groove 77 continues to the upper end of the groove 71 at a level difference 84.
As described above, the grooves 71 through 77 are continuous around the central region 90, starting from the groove 71, passing the grooves 72 through 77 in this order, and eventually returning to the groove 71, via the level differences 81 through 84. The central region 90 has a substantially V-shape in front view, and is on the same plane as portions of the guiding groove arrangement portion 53f where the guiding groove 53h is not arranged.
The groove 74 and the groove 76 connect to each other through the groove 75, which has a V-shape. The groove 75 is formed by the bottom surface 79, an upper side wall 75a, and a lower side wall 75b. The upper side wall 75a and the lower side wall 75b both protrude from the bottom surface 79. The upper side wall 75a and the lower side wall 75b each have a V-shape in front view and an angular portion in a downward direction. A position of an angular portion 92 of the lower side wall 75b is slightly removed to the right from a position of an angular portion 91 of the upper side wall 75a. Further, a position of an angular portion 93 at a lower end of the central region 90 is slightly removed to the right from the groove 71. The reason why the angular portions 91 and 92 are removed from each other and the angular portion 93 is removed from the groove 71 is described later.
Going back to
As described above, the guiding rod 58 is fixed to the upper body portion 52b. However, the operation member 53 is movable in the Z-axis direction relative to the upper body portion 52b. Accordingly, when the operation member 53 moves in the Z-axis direction, the bent portion 58a moves relative to the grooves 71 through 77 of the guiding groove 53h so that the bent portion 58a traces a locus of a Y-shape along the grooves 71 through 77 (hereinafter referred to as a relative movement). Details of this relative movement are described later.
The lever 54 is a plate-like member elongated in the Z-axis direction along one wall 52a, and the lever 55 is a plate-like member elongated in the Z-axis direction along the other wall 52a. The levers 54 and 55 and the two walls 52a are arranged such that the two walls 52a are between the levers 54 and 55 in the Y-axis direction. The levers 54 and 55 have symmetry about line 5z (
As illustrated in
As illustrated in
That is, the lever 55 has a through hole 55b into which a pin 52j standing on the upper body portion 52b fits. The upper end 55a of the lever 55 is always biased in a direction indicated by arrow C by a biasing force from the compression spring 62 at the upper body portion 52b and is pressed onto the receiving portion 53a of the operation member 53.
The lever 54 has, at a surface of its lower end portion in a direction away from a center of the body 52, the protrusions 54c for locking the rear end regulation plate 15. Likewise, the lever 55 has, at another surface of its lower end in a direction away from the center of the body 52, the protrusions 55c for locking the rear end regulation plate 15.
As illustrated in
The cover 57 shields the upper body portion 52b from the outside of the upper body portion 52b so that members at the upper body portion 52b, such as the guiding rod 58 and the compression springs 61 through 63, are not seen by a user. Further, the cover 57 has a function of lidding the upper body portion 52b so that the levers 54 and 55 do not come off. That is, the cover 57 prevents the lever 54, which is supported by the pin 52d, from coming off the pin 52d. Likewise, the cover 57 prevents the lever 55, which is supported by the pin 52j, from coming off the pin 52j. Further, the cover 57 has a function of causing the leaf spring 59 to deflect so that the leaf spring 59 can apply a biasing force to the guiding rod 58.
In the structure described above, both a locking operation and an unlocking operation are achieved by a push-down operation of the operation member 53 by a user. That is, a push-down operation establishes locking of the rear end regulation plate 15, and performing a push-down operation again causes the rear end regulation plate 15 to be released from the locking. The following provides a detailed explanation.
As illustrated in
When a user pushes down the operation member 53 in the locked state illustrated in
When the push-down force applied by the user becomes stronger and the forces in the directions opposing the biasing forces from the compression springs 61 and 62 become stronger than the biasing forces from the compression springs 61 and 62, the operation member 53 descends. In accordance with the descending of the operation member 53, the tapered surfaces 53m of the operation member 53 descend while maintaining their orientations. This causes the upper end 54a and the upper end 55a to move relative to the tapered surfaces 53m so that the upper ends 54a and 55a climb up the tapered surfaces 53m.
This relative movement causes the compression springs 61 and 62 to compress and the lever 54 to swing about the pin 52d and the lever 55 to swing about the pin 52j in the directions indicated by arrows D. Eventually, the protrusions 54c and 55c stop in positions inward of the base 51 (unlocked state), as illustrated in
As described in “Problems to be Solved by the Invention” above, in a structure in which the operation member 53 automatically returns to its original initial position (i.e. the locked state) because of biasing forces from the compression springs 61 through 63 when the user performs unlocking by pushing down the operation member 53 and then removes her or his hand from the operation member 53, the user has to continue pushing down the operation member 53 in order to maintain the unlocking when moving the rear end regulation plate 15 to another regulation position. This is a burden for a user. Further, when a force of pushing down the operation member 53 increases and friction between the base 51 of the rear end regulation plate 15 and the low-floor portion 16a of the bottom surface 10 increases accordingly, the friction may function as a braking force against the movement of the rear end regulation plate 15. This makes it difficult for the user to move the rear end regulation plate 15.
In view of this, the present embodiment has a structure in which the operation member 53 does not return to its original initial position and stops at a holding position at which unlocking of the rear end regulation plate 15 is maintained even when the user removes her or his hand from the operation member 53 after unlocking the rear end regulation plate 15. Maintenance of the unlocking is terminated when the user pushes down the operation member 53 again, and the operation member 53 returns to the initial position and transition to the locked state is achieved. This structure is achieved by the bent portion 58a of the guiding rod 58 being guided and moved along the guiding groove 53h of the operation member 53 in accordance with a push-down operation of the operation member 53 by a user.
As illustrated in
When a user pushes down the operation member 53 at the initial position, the guiding groove arrangement portion 53f, at which the guiding groove 53h is arranged, descends in accordance with descending of the operation member 53 as illustrated in
Because the guiding groove 53h moves downward relative to the guiding rod 58, the bent portion 58a moves relative to the guiding groove arrangement portion 53f in accordance with descending of the guiding groove arrangement portion 53f, so that the bent portion 58a is guided along the guiding groove 53h.
In the present embodiment, the levers 54 and 55 are not engaged with the recesses 16c of the bottom surface 10 (i.e. the unlocked state) when the bent portion 58a, which is guided along the guiding groove 53h, is at any position above a boundary position 101 (broken line) illustrated in
As illustrated in
Further, the bent portion 58a is biased by the biasing force from the leaf spring 59 described above so that the bent portion 58a is always in contact with the bottom surface 79 of the guiding groove 53h. Due to this, the bent portion 58a is prevented from moving over the level difference 84, and cannot move from the groove 71 to the groove 77 before reaching the angular portion 93. The bent portion 58a thus is guided along the level difference 84 inclining obliquely left and upward, and to the groove 72.
When the user removes her or his hand from the operation member 53 in the unlocked state illustrated in
When the operation member 53 moves upward, the bent portion 58a moves from the groove 73, through the branching position 73a, to the groove 74, then through the level difference 82 to the V-shaped groove 75, and is hooked to the angular portion 92 (bending portion) of the lower side wall 75b of the groove 75 as illustrated in
The biasing force from the compression spring 63 in the upward direction is continuously applied to the operation member 53. However, an upward movement of the operation member 53 is prevented when the bent portion 58a is hooked to the angular portion 92 of the groove 75. This causes the operation member 53 to stop. In this sense, the guiding rod 58 functions as a stopper that prevents the operation member 53, when no operation (operation force) is applied by a user, from moving to its original initial position due to the biasing forces from the compression springs 61 through 63.
Because a position at which the operation member 53 stops illustrated in
The position at which the operation member 53 stops when the bent portion 58a is at the angular portion 92 (bending portion) of the groove 75 as illustrated in
When the operation member 53 is at the unlocking holding position, no push-down force from a user is applied to the operation member 53 because the user has removed her or his hand from the operation member 53. That is, the unlocking is maintained without relying upon a user operation (in other words, a force applied by a user).
The user can move the rear end regulation plate 15 along the groove portion 16b of the guiding region 16 to a desired regulation position by applying only a small amount of force while the unlocking is maintained.
When the user removes her or his hand from the operation member 53 in
In this sense, the level difference 81 functions as a switching portion having the following functions. Firstly, the switching portion guides the bent portion 58a (engagement protrusion) of the guiding rod 58, which has been guided along the grooves 71 and 72 (first groove portion), so that the bent portion 58a enters the groove 73 (second groove portion) from the branching position 73a. Due to no operation by the user being applied to the operation member 53, the operation member 53 moves in the direction returning to the initial position. Then, the switching portion guides the bent portion 58a, which moves along the groove 73 in a direction returning to the branching position 73a, so that the bent portion 58a enters the grooves 74 and 75 (second groove) from the branching position 73a, in accordance with the movement of the operation member 53 returning to the initial position.
The switching portion is not limited to the example of the level difference 81; it suffices that the switching portion has the function of switching the destination of the bent portion 58a. One example of a mechanism that may be used as the switching portion is a branching mechanism that allows the bent portion 58a to proceed from the groove 72 to the groove 73 and from the groove 73 to the groove 74 while preventing the bent portion 58a from returning from the groove 73 to the groove 72.
When the user has moved the rear end regulation plate 15 to a desired regulation position and pushes down the operation member 53 illustrated in
When the operation member 53 descends due to the push-down operation in
When the user removes her or his hand from the operation member 53 in a state in which the operation member 53 has been pushed down as illustrated in
When the user pushes down the operation member 53 (
Further, the grooves 76 and 77 function as third grooves for guiding the bent portion 58a (engagement protrusion) of the guiding rod 58 back from the angular portion 92 of the groove 75 to the home position at the groove 71.
When the operation member 53 ascends due to the biasing forces from the compression springs 61 through 63 because the user has removed her or his hand from the operation member 53 in
As described above, in the present embodiment, a user can establish unlocking of the rear end regulation plate 15 and maintain the unlocking of the rear end regulation plate 15 by pushing down the operation member 53 one time when in the locked state. By pushing down the operation member 53 one time when in the holding unlocking state, the user can terminate holding of the unlocking, and returning to the locked state is achieved.
Consequently, the user does not have to apply a force for maintaining the unlocking to the rear end regulation plate 15 in the unlocking holding state while the user moves the rear end regulation plate 15. The user can move the rear end regulation plate 15 in the sheet feed direction by applying a small amount of force with her or his finger to the rear end regulation plate 15. This accordingly reduces the user's burden and facilitates moving of the rear end regulation plate 15.
Further, in the present embodiment, the shapes of the recesses 16c at the guiding region 16 of the bottom surface 10, the protrusions 54c, and the protrusions 55c are devised so that the rear end regulation plate 15 can be unlocked even when in the locked state, upon receiving a force greater than a certain amount.
Specifically, as illustrated in
The edge 54d of the protrusions 54c, which inclines relative to the Y-axis direction, receives a force (reaction) from the side wall 16d. Here, a component of the force (reaction) in a direction indicated by arrow Y functions as a force moving the lever 54 in the direction indicated by arrow Y. A biasing force in a direction opposite the direction indicated by arrow Y is applied to the lever 54 by the compression spring 61. When the force in the direction indicated by arrow Y applied to the protrusions 54c becomes greater than the force applied by the compression spring 61, the lever 54 moves in the direction indicated by arrow Y and the rear end regulation plate 15 is unlocked.
Accordingly, even when a user forgets to push down the operation member 53 of the rear end regulation plate 15 and applies a force greater than necessary to the rear end regulation plate 15 in the locked state in order to forcibly move the rear end regulation plate 15 in the sheet feed direction, the protrusions 54c move so as to escape from the recess 16c, leading to the rear end regulation plate 15 unlocking. This structure prevents problems such as breakage of the protrusions 54c. The protrusions 55c have a similar structure.
Meanwhile, an edge 54e of the protrusions 54c at a back in the sheet feed direction is parallel to the Y-axis direction. Accordingly, even when a force in a direction opposite the sheet feed direction is applied, the locked state is maintained. For example, the edge 54e of the protrusions 54c may also incline in a direction (sheet feed direction) away from the side wall 16e of the recess 16c toward the tip of the edge 54e. Alternatively, the edges 54d and 54e of the protrusions 54c may both be parallel to the Y-axis direction.
Although description of the present invention has been provided with reference to an embodiment thereof, the present invention should not be construed as being limited to the above embodiment, and the following modifications are possible.
(1) In the above embodiment, the guiding groove arrangement portion 53f of the operation member 53 has the Y-shaped guiding groove 53h, and the bent portion 58a is guided along the guiding groove 53h in accordance with ascending and descending of the operation member 53. However, the present invention should not be construed as being limited to this. The present invention may also include structures that achieve, after transition from the locked state to the unlocked state, switching into the unlocking holding state that maintains the unlocking and switching from the unlocking holding state into the locked state.
For example, as an example of alternating actions, a ratchet cam system may be adopted to achieve a structure in which a cam rotates at a predetermined angle and stops each time the operation member 53 is pushed down. In this structure, upon each rotation of the cam at the predetermined angle, one of the following is alternately performed due to swinging of the levers 54 and 55: (i) the levers 54 and 55 moving from the engagement positions illustrated in
(2) The above embodiment describes a structure in which the operation member 53 has the guiding groove 53h and the guiding rod 58 (engagement protrusion) is fixed to the body 52, but the present invention should not be construed as being limited to this. For example, the present invention may also include a structure in which the body 52 has a guiding groove and the operation member 53 has an engagement protrusion. In such a structure, the guiding groove at the body 52 may be a vertical inversion of the guiding groove 53h illustrated in
That is, when a user pushes down the operation member 53 at the initial position (locked state), the engagement protrusion fixed to the operation member 53 is guided along the grooves 71 through 73 (first groove) of the guiding groove at the body 52 in accordance with descending of the operation member 53. When the operation member 53 starts to ascend due to the user removing her or his hand from the operation member 53, the engagement protrusion of the operation member 53 is guided along the groove 73, through the branching position 73a, and to the groove 74 and the groove 75, and the operation member 53 stops at the unlocking holding position (unlocking holding state).
When the user pushes down the operation member 53 resting at the unlocking holding position, the engagement protrusion fixed to the operation member 53 is guided from the groove 75 along the groove 76. When the operation member 53 starts to ascend due to the user removing her or his hands from the operation member 53, the engagement protrusion of the operation member 53 is guided from the groove 76, through the groove 77, to the groove 71, and the operation member 53 stops at the initial position (locked state).
(3) In the above embodiment, the user performs an operation of pushing down the operation member 53, but the present invention should not be construed as being limited to this. For example, the present invention may also include a structure in which the operation member 53 is pulled up. Specifically, the tapered portion 53d of the operation member 53 illustrated in
In such a structure, the operation member 53 always receives a biasing force in the downward direction from the tension spring. When the user pulls up the operation member 53 from the initial position, the bent portion 58a is guided along the guiding groove 53h in the order of the groove 71, the groove 72, and the groove 73, and the unlocked state is achieved. When the user removes her or his hand from the operation member 53 after unlocking, the operation member 53 starts to descend. In accordance with the start of descending of the operation member 53, the bent portion 58a is guided in the order or the groove 73, the groove 74, and the groove 75, and the bent portion 58a is hooked to the angular portion 92 of the groove 75. This causes the operation member 53 to stop in the middle of descending (unlocking holding).
When the user pulls up the operation member 53 and then removes her or his hand from the operation member 53, the bent portion 58a is guided to the groove 75, the groove 76, and the groove 77 in this order, and returns to the groove 71, and the operation member 53 stops at the initial position (locked state).
(4) In the above embodiment, the operation member 53 functions both as the disengaging portion establishing the unlocking of the levers 54 and 55 and the unlocking holding portion maintaining the unlocking, but the present invention should not be construed as being limited to this.
For example, the present invention may also include a structure in which unlocking is performed by the operation member 53 and holding of the unlocking is performed by a hook-shaped member other than the operation member 53. Specifically, such a hook-shaped member may be a stopper that is directly hooked to (engaged with) the levers 54 and 55 when the levers 54 and 55 move to the disengagement positions and holds the levers 54 and 55 at the disengagement positions against the biasing forces from the compression springs. The present invention may further include, for example, another holding terminating member that terminates holding of unlocking by engaging with the stopper upon receiving an operation force by a user and consequently disengaging the stopper from the levers 54 and 55.
(5) The above embodiment describes a structure in which compression springs are used as members biasing the levers 54 and 55 to the engagement positions, at which the levers 54 and 55 engage with the recesses 16c. However, the present invention should not be construed as being limited to this, and another elastic member or the like may be used as a biasing member.
(6) The above embodiment describes an example of a structure in which the sheet stacking device is applied to a tandem-type printer as an example of an image forming device, but the present invention should not be construed as being limited to this. The present invention is applicable to sheet stacking devices in image forming devices such as copiers, facsimile devices, and multi-function peripherals (MFPs).
Further, description is given of an example of a structure of the rear end regulation plate 15 as a regulation member regulating sheets housed in the sheet feed cassette 31, but the present invention should not be construed as being limited to this. For example, the present invention is applicable to the side regulation plates 13 and 14. Further, the present invention should not be construed as being applicable only to the sheet feed cassette 31. For example, the present invention is applicable to a structure in which the storage tray 36, in which a sheet after image forming is stacked and housed, has a regulation member.
Further, in the above embodiment, the locking of the rear end regulation plate 15 is achieved by the protrusions 54c (engaged portion) of the lever 54 engaging with a recess (engaging portion) 16c of the bottom surface 10. However, the present invention should not be construed as being limited to engagement between a protrusion and a recess. For example, the present invention may also include a structure in which the rear end regulation plate 15 has a protruding portion and the bottom surface 10 has a rack with which the protruding portion engages.
Further, in the above embodiment, the rear end regulation plate 15 is supported so that the rear end regulation plate 15 is movable along the guiding region 16 of the bottom surface 10. However, the present invention should not be construed as being limited to this; any structure is possible as long as the rear end regulation plate 15 is supported by the sheet stack unit 10a, so that the rear end regulation plate 15 is movable in a direction toward sheets S stacked and housed on the bottom surface 10 and in a direction away from the sheets S.
Further, any possible combinations of the above-described embodiment and the modifications are construed as being included in the scope of the present invention.
The above embodiment and modifications represent one aspect for solving the problem described in “Problems to be Solved by the Invention”, and is summarized as in the following.
That is, a sheet stacking device reflecting one aspect of the present invention includes: a stacking unit in which a sheet is stacked; and a regulation member that is movably supported by the stacking unit and is brought into contact with an edge of the sheet to regulate a position of the sheet. In the sheet stacking device, the regulation member includes: a locking member that is movable between an engagement position and a disengagement position, the engagement position being a position at which the locking member is engaged with an engaging portion of the stacking unit, and the disengagement position being a position at which the locking member is disengaged from the engaging portion; a biasing member that biases the locking member toward the engagement position; a force receiver that receives a user operation; a releaser that converts a first force in a first direction applied to the force receiver by a user operation into a second force in a second direction opposing a biasing force from the biasing member and being applied to the locking member, moving the locking member from the engagement position to the disengagement position; and a stopper that, after the locking member disengages from the engaging portion and a user operation is not applied to the force receiver, prevents a movement of the locking member back to the engagement position due to the biasing force from the biasing member.
In the sheet stacking device, the regulation member may further include a body, the force receiver and the releaser forming an operation member that is supported by the body and movable in the first direction, the releaser may apply the second force to the locking member when the operation member moves in the first direction from an initial position due to a user operation, the initial position being a position of the operation member when the locking member is at the engagement position, the operation member may be biased toward the initial position by the biasing member after the locking member disengages from the engaging position and a user operation is not applied to the operation member, and the stopper may engage with the operation member and act against the biasing force from the biasing member to stop the operation member at an unlocking holding position, thereby holding the locking member at the disengagement position.
In the sheet stacking device, the releaser may have a tapered surface that is a surface of a tapered portion of the releaser, the tapered portion tapering relative to the first direction, and converting the first force into the second force in accordance with an angle at which the tapered portion tapers and applies the second force to the locking member.
The sheet stacking device may further include a holding terminating portion that disengages the operation member resting at the unlocking holding position and the stopper, thereby terminating holding of the locking member at the disengagement position by the stopper.
In the sheet stacking device, when a force in the first direction is applied to the operation member resting at the unlocking holding position, the holding terminating portion may release the engagement between the operation member and the stopper with use of the force in the first direction.
In the sheet stacking device, the operation member may have a guiding groove defined by guiding groove walls, the stopper may be an engagement protrusion that is fixed to the body and engages with a surface of the guiding groove walls, the guiding groove may include: a first groove elongated in the first direction; a second groove branching from a branching position of the first groove; and a switching portion at the branching position, the first groove may be divided, at the branching position, into a first groove portion and a second groove portion, the second groove may include an inclining groove portion and a bending groove portion, the bending groove portion having a bending portion, when denoting a direction that is along the first groove portion and away from the branching position as a third direction, the inclining groove portion may extend from the branching position at an acute angle from the third direction and connect to the bending groove portion, the bending groove portion may bend at the bending portion in a direction away from the third direction, when denoting a position of the engagement protrusion when the operation member is at the initial position as a home position, as the operation member moves in the first direction from the initial position and the engagement protrusion moves from the home position along the first groove portion toward the branching position, the switching portion may guide the engagement protrusion so that the engagement protrusion passes the branching position and enters the second groove portion, and when the engagement protrusion is at the second groove portion and the user operation is not applied, the switching portion, as the operation member moves toward the initial position and the engagement protrusion moves in a direction returning to the branching position along the second groove portion, may guide the engagement protrusion so that the engagement protrusion moves from the branching position, through the inclining groove portion, to the bending portion of the bending groove portion.
In the sheet stacking device, when a force in the first direction is applied by a user to the operation member resting at the unlocking holding position, the operation member may move from the unlocking holding position, subsequently, when a user operation is not applied to the operation member, the operation member may return to the initial position due to the biasing force from the biasing member, the guiding groove may include a third groove, and when the engagement protrusion moves from the bending portion in accordance with a movement of the operation member from the unlocking holding position to the initial position, the engagement protrusion may be guided by the third groove to the home position at the first groove portion.
In the sheet stacking device, the operation member may further include an engagement protrusion, the body may have a guiding groove defined by guiding groove walls, the stopper may be a surface of the guiding groove walls that engages with the engagement protrusion, the guiding groove may include: a first groove elongated in the first direction; a second groove branching from a branching position of the first groove; and a switching portion at the branching position, the first groove may be divided, at the branching position, into a first groove portion and a second groove portion, the second groove may include an inclining groove portion and a bending groove portion, the bending groove portion having a bending portion, when denoting a direction that is along the first groove portion and away from the branching position as a third direction, the inclining groove portion may extend from the branching position at an acute angle from the third direction and connect to the bending groove portion, the bending groove portion may bend at the bending portion in a direction away from the third direction, when denoting a position of the engagement protrusion when the operation member is at the initial position as a home position, as the operation member moves in the first direction from the initial position and the engagement protrusion moves from the home position along the first groove portion toward the branching position, the switching portion may guide the engagement protrusion so that the engagement protrusion passes the branching position and enters the second groove portion, and when the engagement protrusion is at the second groove portion and the user operation is not applied, the switching portion, as the operation member moves toward the initial position and the engagement protrusion moves in a direction returning to the branching position along the second groove portion, may guide the engagement protrusion so that the engagement protrusion moves from the branching position, through the inclining groove portion, to the bending portion of the bending groove portion.
In the sheet stacking device, when a force in the first direction is applied by a user to the operation member resting at the unlocking holding position, the operation member may move from the unlocking holding position, subsequently, when a user operation is not applied to the operation member, the operation member may return to the initial position due to the biasing force from the biasing member, the guiding groove may include a third groove, and when the engagement protrusion moves from the bending portion in accordance with a movement of the operation member from the unlocking holding position to the initial position, the engagement protrusion may be guided by the third groove to the home position at the first groove portion.
In the sheet stacking device, the first direction may be a direction in which the operation member is pushed down.
The sheet stacking device may further include a holding terminating portion terminating holding of the locking member at the disengagement position by the stopper.
An image forming device reflecting another aspect of the present invention conveys a sheet from a sheet stacking unit to a conveyance path and forms an image on the sheet, the image forming device including: a regulation member that is movably supported by the sheet stacking unit and is brought into contact with an edge of the sheet to regulate a position of the sheet. In the image forming device, the regulation member includes: a locking member that is movable between an engagement position and a disengagement position, the engagement position being a position at which the locking member is engaged with an engaging portion of the sheet stacking unit, and the disengagement position being a position at which the locking member is disengaged from the engaging portion; a biasing member that biases the locking member toward the engagement position; a force receiver that receives a user operation; a releaser that converts a first force in a first direction applied to the force receiver by a user operation into a second force in a second direction opposing a biasing force from the biasing member and being applied to the locking member, moving the locking member from the engagement position to the disengagement position; and a stopper that, after the locking member disengages from the engaging portion and a user operation is not applied to the force receiver, prevents a movement of the locking member back to the engagement position due to the biasing force from the biasing member.
A regulation member reflecting yet another aspect of the present invention is movably supported by a stacking unit in which a sheet is stacked and is brought into contact with an edge of the sheet to regulate a position of the sheet, the regulation member including: a locking member that is movable between an engagement position and a disengagement position, the engagement position being a position at which the locking member is engaged with an engaging portion of the stacking unit, and the disengagement position being a position at which the locking member is disengaged from the engaging portion; a biasing member that biases the locking member toward the engagement position; a force receiver that receives a user operation; a releaser that converts a first force in a first direction applied to the force receiver by a user operation into a second force in a second direction opposing a biasing force from the biasing member and being applied to the locking member, moving the locking member from the engagement position to the disengagement position; and a stopper that, after the locking member disengages from the engaging portion and a user operation is not applied to the force receiver, prevents a movement of the locking member back to the engagement position due to the biasing force from the biasing member.
The above-described structure maintains the unlocked state with use of the stopper, without relying upon a user operation. Because of this, a user does not have to apply to the regulation member a force greater than, for example, a restoring force of a spring for performing unlocking. The user can move the regulation member to a regulation position by applying a small amount of force with his/her finger to the regulation member. This makes it easy for the user to move the regulation member.
Although one or more embodiments of the present invention have been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and not limitation; the scope of the present invention should be interpreted by terms of the appended claims.
Number | Date | Country | Kind |
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2016-148773 | Jul 2016 | JP | national |