Sheet stacker and image forming apparatus

A sheet stacker includes a sheet adjuster movable to regulate a position of a sheet in the sheet stacker, an operation portion to release the sheet adjuster when the operation portion moves in a predetermined direction, and a lock movable together with the sheet adjuster and the operation portion to regulate a movement of the operation portion in the predetermined direction.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35 U.S.C. § 119 to Japanese Patent Application No. 2017-225783, filed on Nov. 24, 2017 in the Japanese Patent Office, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND

Technical Field

This disclosure relates to a sheet stacker such as a sheet tray in which sheets such as paper sheets are stacked and an image forming apparatus such as a copier, a printer, a facsimile machine, or a multifunction peripheral having at least two of the copier, printer, and facsimile machine functions and incorporating the sheet stacker.

Related Art

A known sheet stacker such as a sheet tray included in an image forming apparatus such as a copier or a printer includes a sheet adjuster such as a fence to set a position in the width direction and the conveying direction of stacked sheets.

SUMMARY

This specification describes an improved sheet stacker that includes a sheet adjuster movable to regulate a position of a sheet in the sheet stacker, an operation portion to release the sheet adjuster when the operation portion moves in a predetermined direction, and a lock movable together with the sheet adjuster and the operation portion to regulate a movement of the operation portion in the predetermined direction.

This specification further describes an improved image forming apparatus incorporating the sheet stacker described above.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring now to the drawings, embodiments of the present disclosure are described below. In the drawings illustrating the following embodiments, the same reference codes are allocated to elements (members or components) having the same function or shape and redundant descriptions thereof are omitted below.

With reference toFIG. 1, an overall configuration and operation of an image forming apparatus1is described below.

InFIG. 1, the image forming apparatus1, in this case a copier, includes a scanner2, an exposure device3, an image forming device4, a transfer device7, a document conveying device10such as an automatic document feeder, a sheet feeding device12, a sheet feeding device13, a manual sheet feeding device16, a pair of registration rollers17, a fixing device20, a sheet output tray31, a sheet stacker40and a sheet feeding mechanism52. The scanner2optically reads image data of an original document D. The exposure device3emits exposure light L based on image data read by the scanner2to irradiate the surface of the photoconductor drum5. The image forming device4forms a toner image on the photoconductor drum5. The transfer device7transfers the toner image formed on the surface of the photoconductor drum5onto a sheet P. The document conveying device10conveys the document D set on a document tray to the scanner2. The sheet feeding device12and the sheet feeding device13feed a sheet P accommodated in the sheet stacker40. The manual sheet feeding device16feeds the sheet P which a user sets manually. The pair of registration rollers17conveys the sheet P to the transfer device7. The fixing device20includes a fixing roller21and a pressing roller22and fixes the toner image transferred onto the sheet P on the sheet P. The sheet P ejected from the image forming apparatus body is stacked on the sheet output tray31. The sheet stacker40such as a sheet tray is a sheet stacker in each of the sheet feeding devices12and13. The sheet feeding mechanism52is in each of the sheet feeding devices12,13, and16.

A standard image forming operation of the image forming apparatus1illustrated inFIG. 1is described below.

The original document D is fed from the document tray by conveyance rollers of the document conveying device10and passes over the scanner2. The scanner2optically reads the image data on the document D passing over the scanner2.

The optical image data read by the scanner2is converted to electrical signals that are transmitted to the exposure device3. Then, the exposure device3emits exposure light L such as the laser light based on the image data of the electrical signals toward the surface of the photoconductor drum5of the image forming device4.

In the image forming device4, the photoconductor drum5rotates clockwise inFIG. 1, and a toner image according to the image data is formed on the photoconductor drum5through predetermined image forming processes such as charging, exposure, and developing processes.

Thereafter, the transfer device7transfers the toner image formed on the photoconductor drum5onto the sheet P conveyed by the pair of registration rollers17.

By contrast, the sheet P that is conveyed to the transfer device7is handled as described below.

Initially, one of the sheet feeding devices12and13in the image forming apparatus1is selected automatically or manually. For example, the lower sheet feeding device13is selected. Then, the sheet feeding mechanism52feeds and conveys the uppermost one of the sheets P stored in the sheet stacker40of the sheet feeding device13toward a sheet conveyance path K. Thereafter, the sheet P passes through the sheet conveyance path K in which multiple sheet conveying rollers are disposed and reaches the pair of registration rollers17.

When the user selects the manual sheet feeding device16disposed at one side of the image forming apparatus body, the sheet P set on a manual sheet feeding tray of the manual sheet feeding device16by the user (the uppermost sheet p when a plurality of sheets are set on the manual sheet feeding tray) is fed toward the sheet conveyance path K by the sheet feeding mechanism52and reaches the pair of registration rollers17.

The pair of registration rollers17aligns and conveys the sheet P toward the transfer device7when the image formed on the photoconductor drum5meets the sheet P.

After completion of the transfer process, the sheet P passes the transfer device7and reaches the fixing device20via the sheet conveyance path K. In the fixing device20, the sheet P is conveyed between the fixing roller21and the pressing roller22, so that the toner image is fixed on the sheet P by heat applied by the fixing roller21and pressure applied by the fixing roller21and the pressing roller22, which is a fixing process. The sheet P with the toner fixed thereto after the fixing process passes a fixing nip region formed between the fixing roller21and the pressing roller22. Then, the sheet P is ejected from the image forming apparatus1. After having been ejected from the image forming apparatus1, the sheet P is stacked as an output image, on the sheet output tray31, thus completing the image formation process

Although the following description relates to the lower sheet feeding device13of the sheet feeding devices12and13in the image forming apparatus1, the upper sheet feeding device12has the same structure as the lower sheet feeding device13except their positions. Therefore, a description of the sheet feeding device12is omitted.

FIG. 2is a diagram illustrating the sheet feeding device13included in the image forming apparatus1. The sheet feeding device13includes the sheet stacker40such as the sheet tray designed to load one or more sheets P and the sheet feeding mechanism52to feed the sheet P loaded on the sheet stacker40.

The sheet stacker40includes a bottom plate42capable of moving up and down, side fences46serving as a sheet adjuster movable in a width direction of the sheet P, an end fence47serving as the sheet adjuster movable in a feeding direction, which is described later in detail with reference toFIGS. 3 to 6.

As illustrated inFIG. 2, the sheet feeding mechanism52includes a feed roller53, a pickup roller54, and a separation roller55.

The feed roller53is disposed on the leading end side of the sheet P stacked on the bottom plate42of the sheet stacker40in the feeding direction that is the direction of arrow R1inFIG. 2and is the sheet conveyance direction. The feed roller53contacts the upper surface of the sheet P, rotates in the feeding direction of the sheet P, that is, counterclockwise inFIG. 2, and feeds the sheet P in the feeding direction indicated by an arrow R2inFIG. 2, that is, +X direction.

The pickup roller54contacts the upper surface of the sheet P stacked on the sheet stacker40, rotates in a counterclockwise direction along the feeding direction of the sheet P, and conveys the sheet P toward the feed roller53.

The timing belt59is supported by and entrained around a pulley at the pickup roller54and a pulley at the feed roller53. When a driving force is transmitted from a feed motor to the pickup roller54via a gear train, the feed roller53, and the timing belt59, the pickup roller54rotate counterclockwise inFIG. 2.

The pickup roller54is configured to be able to contact and separate from the uppermost sheet P stacked on the sheet stacker40. That is, the pickup roller54is movable between a retracted position at which the pickup roller54does not contact the sheet P stacked on the sheet stacker40and a contact position at which the pickup roller54contacts the sheet P.

Specifically, the pickup roller54is rotatably held by the arm58. The arm58is rotatably held by a shaft of the feed roller53. A spring and a solenoid are connected to the arm58. The spring urges the pickup roller54to move to the retracted position, and the solenoid resists the urging force of the spring to move the pickup roller54to the contact position. A controller controls the solenoid to move the pickup roller54to the contact position when the solenoid is activated and, when the solenoid is not activated, move the pickup roller54to the retracted position.

Even when the pickup roller54is moved to the contact position or the retracted position, the timing belt59is supported by and entrained around the pulley at the pickup roller54and the pulley at the feed roller53.

The separation roller55is disposed to form a nip portion between the separation roller55and the feed roller53.

The separation roller55rotates in a forward direction, which is the clockwise direction indicated by dashed arrow R3inFIG. 2, along the feeding direction when one sheet P is nipped at the nip portion and when the sheet P is not nipped at the nip portion.

By contrast, when a plurality of sheets P is nipped at the nip portion, the separation roller55rotates in a direction opposite to the forward direction which is the counterclockwise direction illustrated by solid arrow R4inFIG. 2. As a result, the rotation of the feed roller53feeds the uppermost sheet P among the plurality of sheets P sandwiched at the nip portion, and the rotation of the separation roller55moves the lower sheet P among the plurality of sheets P in the direction opposite to the forward direction that is the feeding direction, which prevents multiple feeding of the sheets P.

In the sheet feeding device13according to the present embodiment, the bottom plate42moves up and down in the vertical direction depending on the number of sheets P stacked on the bottom plate42so that the pickup roller54can contact the uppermost sheet P stacked in the sheet stacker40. The feeding operation of the sheet P is performed after the pickup roller54descends to the contact position at which the pickup roller54contacts the upper surface of the sheet P placed on the bottom plate42whose position in the vertical direction is adjusted.

In addition, an inlet guide plate is disposed between the sheet stacker40and the nip portion between the feed roller53and the separation roller55.

In the sheet feeding device13configured as described above, when the sheet P is not set in the sheet stacker40, an end-state sensor disposed at a bottom portion detects absence of the sheet P, and the controller controls the solenoid to set the pickup roller54at the retracted position.

When the sheet P is set in the sheet stacker40, the end-state sensor detects presence of the sheet P, and the controller controls the solenoid to move the pickup roller54from the retracted position to the contact position illustrated inFIG. 2.

As illustrated inFIG. 2, the pickup roller54contacts the upper surface of the uppermost sheet P stacked on the bottom plate42and starts to rotate counterclockwise. At the same timing, the feed roller53and the separation roller55start to rotate. The rotation of the pickup roller54feeds the uppermost sheet P in a bundle of sheets stacked in the sheet stacker40toward the nip portion between the feed roller53and the separation roller55, and, at the nip portion, the uppermost sheet P is separated as a single sheet P from the remaining sheets P and conveyed to the transfer device7.

When all sheets P stacked in the sheet stacker40are fed and there is no sheet in the sheet stacker40, the end-state sensor detects the absence of the sheet, and the controller controls the solenoid to move the pickup roller54to the retracted position again.

As illustrated inFIG. 3, the sheet stacker40is a substantially rectangular parallelepiped box-shaped member and includes the bottom plate42, a first guide rail44, a second guide rail45, side fences46, and an end fence47which are disposed on a base41and in the box-shaped member.

An exterior cover43is set on one of the four sides of the sheet stacker40. The exterior cover43includes a handle43a. The user grips the handle43aand inserts and removes the sheet stacker40in the ±Y direction inFIG. 3from the image forming apparatus body. Specifically, the sheet stacker40is removed in the +Y direction with respect to the image forming apparatus body, the sheets P are stacked in the sheet stacker40, and then the sheet stacker40is inserted in the −Y direction into the image forming apparatus body.

The bottom plate42is configured to move up and down by rotation of the bottom plate42in forward and reverse directions around the end position of the rear end side in the feeding direction that is the −X direction inFIG. 3as the rotation center. A mechanism to move the bottom plate42up and down may use a movable plate which is tilted by rotation of motor drive and disposed between the bottom plate42and the base41or a compression spring which urges or limits urging in conjunction with movement of the sheet stacker40.

The sheet stacker40includes the pair of side fences46and the end fence47which surround three sides of a space above the bottom plate42, that is, the space where the sheets P are stacked, which do not surround a leading side in the feeding direction that is +X direction inFIG. 3.

The side fences46function as the sheet adjuster to regulate a position in the width direction, which is ±Y direction inFIG. 3, of the sheet P stacked in the sheet stacker40. The side fences46are respectively provided at both end portions in the width direction to sandwich the sheet P, and are movable in the width direction according to the size in the width direction of the sheet P.

The first guide rail44extends on the base41in the width direction to guide the side fence46movably in the width direction. The side fences46are manually moved in the width direction along the first guide rail44to position the sheet P in the width direction in the sheet stacker40. As a result, the sheet P whose position in the width direction is fixed is smoothly fed from the sheet stacker40.

In the present embodiment, the pair of side fences46is configured to interlock and increase or decrease the interval in the width direction. That is, when one side fence46is manually moved in the +Y direction, the other side fence46moves in conjunction with the −Y direction, and when one side fence46is manually moved in the −Y direction, the other side fence46moves in conjunction with the +Y direction. Such a mechanism to interlock and move the pair of side fences46may use a pinion/rack mechanism including a rack gear unit integrally formed so as to extend in the width direction orthogonally to the one side fence46, another rack gear unit integrally formed so as to extend in the width direction orthogonally to the other side fence46, and a pinion gear sandwiched between the rack gear units and meshing therewith.

The end fence47functions as the sheet adjuster to regulate a rear end position in the feeding direction, which is −X direction inFIG. 3, of the sheet P stacked in the sheet stacker40. The end fence47is provided to contact the rear end of the sheet P in the feeding direction and movable in the feeding direction according to the size in the feeding direction of the sheet P.

The second guide rail45extends on the base41in the feeding direction to guide the end fence47movably in the feeding direction that is ±X direction. The end fence47is manually moved in the feeding direction along the second guide rail45to position the sheet P in the feeding direction in the sheet stacker40. As a result, the sheet P whose position in the feeding direction is fixed is smoothly fed from the sheet stacker40.

With reference toFIGS. 4, 5, and 6A through 6F, an operation portion48band a lock49serving as an operation restricting member are provided on an upper portion of the end fence47serving as a sheet adjuster.

FIGS. 6A, 6C, and 6Eare external views illustrating a pivoting operation of the lock49serving as the operation restricting member.FIGS. 6B, 6D, and 6Fare internal views of a main part corresponding toFIGS. 6A, 6C, and 6E, respectively.

The operation portion48bis moved in a predetermined direction that is the +Y direction inFIG. 4to release the end fence47serving as the sheet adjuster whose position is fixed. That is, the operation portion48bis manually operated and moved in the +Y direction, which changes the end fence47from a fixed state to a released state that enables the end fence47to change the position in the ±X direction that is the feeding direction. After the position of the end fence47in the ±X direction is fixed, the operation portion48bis not operated. Each time the sheet P having a different size is set in the sheet stacker40, the operation portion48bis operated to change the position of the end fence47.

Specifically, as illustrated inFIG. 5, the second guide rail45that movably guides the end fence47serving as the sheet adjuster includes a wall portion to sandwich the lower portion of the end fence47in the Y direction. The wall portion includes a concave portion45bin one side of the wall portion and a slit45ain the other side of the wall portion.

The concave portion45bformed in the one side of the wall portion determines the rear end position of the sheet P having a standard size (A size, such as A4 and A3, or B size, such as B4 and B3) in the feeding direction because an exposed latch claw51aof the end fence47, which is illustrated inFIG. 4, engages the concave portion45b. The latch claw is formed on the tip of an arm51illustrated inFIG. 5. The arm51is elastically and deformably supported in the end fence47.

Regarding the engagement between the concave portion45band the latch claw51a, the shape of the concave portion45band the latch claw51aand the elastic force of the arm51are designed such that a moderate and reliable click feeling can be obtained when the user manually moves the end fence47in the ±X direction, and applying a force of an appropriate magnitude can release the engagement between the concave portion45band the latch claw51a.

As illustrated inFIG. 5, the slit45aof the second guide rail45extends along the ±X direction that is a direction of movement of the end fence47in the other side of the wall portion.

On the other hand, in the end fence47, a pivot member48is supported to be rotatable around a support shaft48athat stands toward the −X direction. The pivot member48includes the operation portion48band a pawl portion48c. The pawl portion48cis a latch pawl that fits the slit45aon a side opposite the operation portion48bseen from the support shaft48a.

In addition, the end fence47includes a compression spring50serving as an urging member that urges the pivot member48so that the pawl portion48cof the pivot member48fits the slit45a. One end of the compression spring50serving as the urging member is coupled to an inner wall of the end fence47, and the other end of the compression spring50is coupled to a bottom portion of the pivot member48. The compression spring50urges the pivot member48so that the operation portion48bmoves in the −Y direction.

In such a structure, as illustrated inFIG. 5, when the operation portion48bis not operated, an urging force of the compression spring50pivots the pivot member48counterclockwise in a Y-Z plane ofFIG. 5. As a result, the pawl portion48cfits the slit45a. This restricts and fixes the position of the end fence47in the ±X direction and positions the end fence47. Therefore, even when the user sets the sheet P having an irregular size which is not the standard size or the sheet P having a minute dimensional error from the standard size due to a cutting error or the like in the sheet stacker40, the user can freely fix and position the end fence47at a position suitable for the size of the sheet P and may not position the end fence47at the position of the concave portion45bfor the standard size.

When the user moves the operation portion48bin the +Y direction, the pivot member48resists the urging force of the compression spring50and is pivoted in the clockwise direction in the Y-Z plane ofFIG. 5, which releases the engagement between the pawl portion48cand the slit45a. This releases the fixed state of the end fence47and enables a manual movement of the end fence47in the ±X direction, that is, sets the end fence47in the released state. In the present embodiment, a mark48b1that is an arrow indicating the +Y direction is formed at the top of the operation portion48b, which supports the user's operation of the operation portion48b.

When the latch claw51ais engaged with the concave portion45bfor the standard size of the sheet P, the pawl portion48cof the pivot member48is fitted to the slit45a. Therefore, when the end fence47is moved in the ±X direction in the above-described state, a same operation for the operation portion48breleases the fixed state of the end fence47.

On the other hand, the lock49serving as the operation restricting member is movable in the ±X direction together with the end fence47and the operation portion48band which regulates and locks the operation of the operation portion48bin a predetermined direction that is, for example, the +Y direction. That is, the lock49functions as a stopper so that the operation portion48bis not moved in the +Y direction in the fixed state of the end fence47. After the end fence47is positioned in the ±X direction, the lock49restricts the movement of the operation portion48bin the +Y direction.

Specifically, as illustrated inFIGS. 4, 5, 6A, and 6B, the lock49serving as the operation restricting member is configured to move between a first position that is a lock release position in which the lock49does not contact the operation portion48band a second position that is a locked position in which the lock49contacts the operation portion48b.

More specifically, as illustrated inFIG. 5, the lock49serving as the operation restricting member is rotatably supported on the end fence47around a boss47aas a pivot shaft so that the lock49is opposed to the front end of the operation portion48bin the predetermined direction that is +Y direction inFIG. 5. The boss47astands on the end fence47in the −X direction. The boss47ais inserted into a through-hole49aof the lock49, and a screw60is screwed into internal threads of the boss47asuch that a branch47bof the end fence47intervenes between the screw60and the boss47a. As illustrated inFIGS. 6A to 6F, this structure enables the lock49on the end fence47to be rotatable about the boss47a.

The lock49allows an operation of the operation portion48bthat moves the operation portion48bin the predetermined direction that is +Y direction when the lock49is set in a first position that is a lock release position illustrated inFIGS. 6A and 6Band prohibits the operation when the lock49is set in a second position that is a lock position illustrated inFIGS. 6E and 6F.

Specifically, with reference toFIGS. 5 and 6A to 6F, the lock49includes a projection49bto which a length from the boss47aserving as the pivot shaft is longer than lengths from the boss47ato other parts of the lock49.

As illustrated inFIGS. 6A and 6B, when a posture of the lock49in a pivoting direction is set so that the projection49bgets away from the operation portion48b, a clearance between the operation portion48band the lock49is enough for the operation portion48bto move in the +Y direction. That is, the end fence47becomes the released state that is a lock released state which enables the end fence47to move in the ±X direction.

After the end fence47is positioned in the ±X direction, the pivot member48is pivoted in an arrow direction ofFIG. 6Dand changes the state illustrated inFIGS. 6A and 6Bto a state illustrated inFIGS. 6C and 6D. As illustrated inFIGS. 6E and 6F, when the posture of the lock49in the pivoting direction is set so that the projection49bis opposite to the operation portion48b, there is no clearance between the operation portion48band the lock49to move the operation portion48bin the +Y direction. That is, the end fence47becomes the fixed state that is a lock state in which the end fence47is immovable in the ±X direction.

When the lock49is switched from the lock state to the lock released state, the lock49is operated and pivoted from the state illustrated inFIGS. 6E and 6Fto the state illustrated inFIGS. 6A and 6Bvia the state illustrated inFIGS. 6C and 6Dcounterclockwise.

As described above, in the present embodiment, after the end fence47is positioned in the ±X direction, the lock49is operated and pivoted to the state illustrated inFIGS. 6E and 6Fto restrict the movement of the operation portion48bin the +Y direction. This appropriately positions the end fence47to set the position of the sheet P and prevents a disadvantage due to misalignment of the end fence47from the appropriate position caused by user's operation error such as an error when the user accidentally moves the operation portion48b. The present embodiment, without attaching and detaching a member, provides easy and hassle-free operation involving pivoting the lock49disposed on the end fence47, which is the lock operation and the lock release operation, switches the end fence47from the fixed state to the fixed release state, or from the fixed release state to the fixed state. The lock49integrated with the end fence47prevents the lock49from dropping off or otherwise getting lost.

As illustrated inFIG. 5, in the present embodiment, the lock49serving as the operation restricting member includes a plurality of protrusions49cserving as an operation limiting member on the outer peripheral surface of the lock49in the direction of movement that is the pivoting direction. Specifically, as illustrated inFIG. 5, when the lock49is in the lock release position, the plurality of protrusions49care on the side surface in the +Y direction and the upper surface of the lock49.

This structure enables the user to easily turn the lock49by putting the user's finger on the protrusions49c.

In this embodiment, the plurality of protrusions49cis provided on the lock49. However, instead of the plurality of protrusions49c, a plurality of recesses on the lock49also have the same effect.

FIG. 7is an enlarged perspective view illustrating a top portion of the end fence as a variation.

As illustrated inFIG. 7, in the present embodiment, the lock49serving as the operation restricting member includes another mark49don the outer peripheral surface of the lock49to indicate that the lock49is in the second position that is the lock position. Specifically, another mark49dmarking a padlock as a key is printed on the upper surface of the lock49positioned at the second position as the lock position. The upper surface is a position visually recognized by the user. By another mark49d, the user can visually recognize that the lock49is at the second position, which supports the user's turning operation.

In the present variation, the lock49includes another mark49dindicating that the lock49is at the second position as the lock position. However, the lock49may include a mark indicating that the lock49is at the first position as the lock release position, or both marks may be included.

As described above, the sheet stacker40of the present embodiment includes the end fence47serving as the sheet adjuster that is movable to regulate the position of the sheet P, the operation portion48bthat changes the end fence47from the fixed state to the released state when the operation portion48bis moved in the predetermined direction, and the lock49serving as the operation restricting member movable together with the end fence47and the operation portion48bto regulate and lock the operation of the operation portion48bin the predetermined direction.

This uncomplicated structure enables the end fence47to freely fix and release at the appropriate positions and prevents a disadvantage due to misalignment of the end fence47from the appropriate position caused by user's operation error.

It is to be noted that the present embodiment of this disclosure is applied to the sheet stacker40provided to the image forming apparatus1that performs monochrome image formation. However, this disclosure is not limited thereto. For example, this disclosure can also be applied to a sheet tray serving as the sheet stacker provided to an image forming apparatus that performs color image formation.

Further, it is to be noted that the present embodiment of this disclosure is applied to the sheet stacker40provided to the image forming apparatus1that employs electrophotography. However, this disclosure is not limited thereto. For example, this disclosure can also be applied to a sheet stacker provided to an image forming apparatus that employs an inkjet method or a stencil printing machine.

Further, it is to be noted that the present embodiment of this disclosure is applied to the sheet stacker40such as the sheet tray in the sheet feeding device13located in the image forming apparatus1. However, this disclosure is not limited thereto. For example, this disclosure can be applied to the manual sheet feeding tray serving as the sheet stacker in the manual sheet feeding device16for the manual sheet feeding tray disposed outside the image forming apparatus1. Further, this disclosure can also be applied to the document tray serving as the sheet stacker in the document conveying device10(the automatic document feeder) as the sheet feeding device.

In such configurations, effects similar to those described above are also attained.

Further, the present embodiment of this disclosure is applied to the end fence47serving as the sheet adjuster including the operation portion48band the lock49serving as the operation restricting member. However, this disclosure is not limited thereto. For example, this disclosure can be applied to the side fence46as a sheet adjuster including the operation portion and the operation restricting member.

Further, the present embodiment includes the structure in which a pivoting operation of the lock49serving as the operation restricting member configured to be rotatable around the rotation axis moves the lock49serving as the operation restriction member between the first position that is the lock release position and the second position that is the lock position. Another structure may be adopted in which a sliding operation of the lock49serving as the operation restricting member configured to be slidable in the ±Y direction, ±X direction or ±Z direction moves the lock49serving as the operation restriction member between the first position that is the lock release position and the second position that is the lock position.

In such configurations, effects similar to those described above are also attained.

The present disclosure is not limited to the above-described embodiments, and the configuration of the present embodiment can be appropriately modified other than suggested in each of the above embodiments within a scope of the technological concept of the present disclosure. Also, the positions, the shapes, and the number of components are not limited to the embodiments, and they may be modified suitably in implementing the present disclosure.

It is to be noted that, as described above, a “sheet” in the above-described embodiments of this disclosure is not limited to indicate regular paper but also includes any other sheet-like material such as coated paper, label paper, an OHP film sheet, a metal film, a film, prepreg, a cloth.