Sheet processing device, image forming device provided with the same, and folded sheet pressing method

Provided is a sheet processing device capable of preventing a folded sheet bundle from being opened after pressing to improve accumulating property and aligning property of the sheet bundle. A sheet processing device B that presses a folded sheet bundle includes a pair of pressing rollers 70 that press a fold of the folded sheet bundle in a thickness direction of the fold, a pressing roller unit 56 that moves the pressing roller pair 70 along the fold of the folded sheet bundle, and a cam member 80 that regulates an interval between the pressing roller pair 70. When the pressing roller unit 56 is moved along the fold of the folded sheet bundle to press the fold in the fold thickness direction, the cam member 80 reduces stepwise the interval between the pressing roller pair 70 in accordance with a moving direction of the pressing roller unit 56.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a device for folding a sheet bundle formed by sheets that are sequentially carried out from an image forming device such as a copier or a printer and accumulated in a bundle and, more particularly, to a sheet processing device that performs pressing against a fold of a two-folded sheet bundle.

Description of the Related Art

There are widely known processing devices that align sheets carried out from an image forming device, bind them, and fold them into a booklet. Among them, some processing devices are configured to saddle-stitch the sheet bundle with a staple or an adhesive and fold the sheet bundle into a booklet.

Such a device performs folding for sheet bundle formed by about 20 to 30 sheets in half; however, there may be a case where the two-folded sheet bundle is unintentionally opened after being discharged from the device, degrading aligning property of the sheet bundle, which results in reduction in accumulation amount.

Thus, it is widely known that, after the folding, the two-folded sheet bundle is subjected to pressing from above and below the fold.

For example, Japanese Patent No. 4,217,640 discloses a device that moves along a fold of a two-folded sheet bundle while pinching/pressing the fold by means of rollers disposed above and below the fold. This device is also provided with a flattening roller that presses the fold from a front side thereof at a position slightly rearward of the pinching/pressing position of the upper and lower rollers. That is, in this device, the rollers that pinch/press the fold from thereabove and therebelow and flattening roller that presses the fold from the front side thereof are formed into one unit, and this unit is moved along the sheet folding direction. Thus, only a portion that is pinched by the rollers can be made flat, thereby reducing wrinkles and breaks of a portion other than the fold due to a difference in gripping force.

Further, as illustrated in detail inFIGS. 11 and 12, Japanese Patent No. 4,217,640 discloses, as a device of a second embodiment of the specification, a device in which a unit provided with a flattening roller that presses the fold from the front side thereof and pinching roller pairs that are arranged at front and rear of the flattening roller so as to pinch/press the fold from thereabove and therebelow moves along the sheet folding direction. A device of such a type moves from outside one end portion of the sheet bundle in its width direction toward inside and passes the other end portion thereof while pinching/press the fold by means of the pinching roller pairs to thereby flatten a back-folded portion.

Further, Jpn. Pat. Appln. Laid-Open Publication No. 2014-76903 discloses a processing device provided with a pair of pressing rollers that press a fold of a two-folded sheet bundle in a sheet width direction and a moving unit that reciprocates the pressing roller pair in the sheet width direction. Further, this processing device is configured to move the pressing roller pair between a position where they are separated away from each other and a position where they are brought into pressure contact with each other. Upon pressing the sheet bundle, the moving unit moves inward from an end portion in the sheet width direction with the pressing roller pair separated away from each other and then moves from the inside to one end portion of the sheet bundle while pressing the sheet bundle. After passing the one end portion, pressing by the pressing roller pair is released to separate the pressing roller pair away from each other. When moving again for pressing, the moving unit passes the one end position of the sheet bundle with the pressing roller pair separated away from each other and then moves from the inside to the other end portion of the sheet bundle while pressing the sheet bundle. In other words, the pressing against the fold of the sheet bundle is started from the inside in the sheet width direction to the one or the other end portion of the sheet bundle.

The above-described devices that perform pressing against the folded sheet bundle carried out from an image forming device or the like have the following problems, respectively.

In the device disclosed in Japanese Patent No. 4,217,640, the roller pair that is previously brought into a pressure contact state is moved along the fold, so that even if the roller pair is reciprocated many times, the roller pair presses the same position, that is, the folded positions are overlapped in a straight line, with the result that the folded sheet bundle may be opened after the pressing. Thus, an accumulating property and an aligning property of the folded sheet bundle cannot be effectively improved.

Also, in the device disclosed in Jpn. Pat. Appln. Laid-Open Publication No. 2014-76903, the pressing against the fold of the sheet bundle by means of the pressing roller pair is repetitively performed with the same pressing force, so that, as in the case of the device disclosed in Japanese Patent No. 4,217,640, the folded positions are overlapped in a straight line, with the result that the folded sheet bundle may be opened after the pressing. Thus, improvement of the accumulating property and aligning property of the folded sheet bundle is conventionally difficult to achieve.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems and based on the following idea. That is, when a fold of a folded sheet bundle is subjected to pressing, a plurality of pressing operations are not made for the same position of the fold but for different positions in a thickness direction of the fold, with the result that created fold lines are directed inward in the sheet thickness direction after the last pressing operation.

To solve the above problem, a sheet processing device includes a pair of sheet pressing members that press a fold of the folded sheet bundle in a thickness direction of the fold, a moving member that moves the sheet pressing member pair along the fold of the folded sheet bundle, and an interval regulating member that regulates an interval between the sheet pressing member pair. When the moving member is moved along the fold of the folded sheet bundle to press the fold in the fold thickness direction, the interval regulating member reduces stepwise the interval between the sheet pressing member pair in accordance with a moving direction of the moving member.

The present invention provides the following effects by having the above features.

The first sheet pressing roller pair in the moving direction is moved in a sheet width direction while pressing the folded sheet bundle in the fold thickness direction in a state of being separated from each other to create a fold, and the second sheet pressing roller pair in the moving direction is moved in the sheet width direction while pressing the folded sheet bundle with the interval therebetween reduced to create a new fold, whereby the fold of the folded sheet bundle is directed inward. Thus, the sheet bundle itself is directed to its binding direction, thereby preventing the folded sheet bundle from being opened after the pressing, which allows more sheet bundles to be accumulated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail based on illustrated embodiments.FIG. 1illustrates an entire configuration of an image forming system according to the present invention including an image forming device,FIG. 2is an explanatory view of an entire configuration of a sheet processing device, andFIGS. 3A to 3Dare views explaining a folded state of a sheet bundle in the sheet processing device.FIG. 4is a perspective view of a sheet pressing device incorporated in the sheet processing device as viewed from the sheet discharge side, andFIG. 5is a cross-sectional view of the sheet pressing device.

The image forming system illustrated inFIG. 1is constituted by an image forming device A and a sheet processing device B, and a sheet pressing device50is incorporated in the sheet processing device B.

[Configuration of Image Forming Device]

The image forming device A illustrated inFIG. 1feeds a sheet from a sheet supply section1to an image forming section2, performing printing for the sheet in the image forming section2, and carries out the resultant sheet from a main body sheet discharge port3. In the sheet supply section1, sheets of a plurality of sizes are housed in sheet cassettes1aand1b, respectively, and sheets of a specified size are fed to the image forming section2while being separated one from another. The image forming section2includes, for example, an electrostatic drum4, a print head (laser emitter)5, a developing unit6, a transfer charger7, and a fixing unit8. The print head5, developing unit6, transfer charger7, and fixing unit8are disposed around the electrostatic drum4. In this image forming section2, the laser emitter5forms an electrostatic latent image on the electrostatic drum4, the developing unit6makes toner adhere to the obtained electrostatic latent image, the transfer charger7transfers an image onto the sheet, and the fixing unit8thermally fixes the image to the sheet. The sheets with the thus formed image are sequentially carried out from the main body sheet discharge port3. A reference numeral9is a circulation path for double-sided printing. More specifically, the sheet on a front side of which the image has been printed is fed from the fixing unit8, reversed in a main body switchback path10, and enters the circulation path9, along which the sheet is fed once again to the image forming section2for printing on a back side of the sheet. The thus double-side printed sheet is reversed in the main body switchback path10and carried out from the main body sheet discharge port3.

A reference numeral11is an image reading device. The image reading device11scans a document sheet set on a platen12using a scan unit13, and light reflected from the document and passing through a reflective mirror and a condenser lens is electrically read by a photoelectric conversion element14. This image data is subjected to, e.g., digital processing in an image processing section, transferred to a data storage section17, from which an image signal corresponding to the resultant image data is transmitted to the laser emitter5. A reference numeral15is a document feeder that feeds a document sheet housed in a document stacker16to the platen12.

A controller is provided in the image forming device A having the above configuration, and image formation conditions, for example, print-out conditions such as sheet size designation, color/monochrome printing designation, number-of-copies designation, one-side/two-side printing designation, and scaling printing designation are set through a control panel18. Further, in the image forming device A, image data read by the scan unit13or image data transferred from an external network is stored in the data storage section17. The image data is transferred from the data storage section17to a buffer memory19, from which data signals corresponding to the image data are sequentially transmitted to the laser emitter5.

Upon input of the image formation conditions, sheet processing conditions are also input (designated) through the control panel18. Through input of the sheet processing conditions, the following modes are designated. The image forming device A forms an image on the sheet according to the image formation conditions and post processing conditions.

[Configuration of Sheet Processing Device]

The sheet processing device B connected to the above-described image forming device A is configured to receive the image-formed sheet from the main body sheet discharge port3of the image forming device A and perform sheet processing according to one of the following modes.

The modes include: (1) “print-out mode” in which the image-formed sheet is housed in a first sheet discharge tray21; (2) “staple-binding mode” in which the sheets from the main body sheet discharge port3are aligned in a bundle, bound by an end face stapler33, and housed in the first sheet discharge tray21; (3) “saddle stitching and folding mode” in which the sheets from the main body sheet discharge port3are aligned in a bundle in a stacker section35which is a second processing tray, bound at a portion near a center thereof using a saddle stitching stapler40, folded into a booklet, and stored in a second sheet discharge tray22; and (4) “folded sheet pressing mode” in which a sheet loop is pressed at a fold of a sheet bundle that has been saddle-stitched and folded into a booklet and then stored in the second sheet discharge tray22.

As illustrated inFIG. 2, the sheet processing device B includes, in a casing20thereof, the first and second sheet discharge trays21and22and a sheet carry-in path P1having a carry-in port23connected to the main body sheet discharge port3. The sheet carry-in port P1is constituted by a straight line path extending in a substantially horizontal direction. Further, first and second switchback conveying paths SP1and SP2are branched from the sheet carry-in path P1, along which the sheet is conveyed in a reverse direction to the conveying direction of the sheet conveyed on the sheet carry-in path P1. The first switchback conveying path SP1is branched from the sheet carry-in path P1at a path downstream side, and the second switchback path SP2is branched from the sheet carry-in path P1at a path upstream side. The first and second switchback conveying paths SP1and SP2are distanced from each other.

In such a path configuration, in the sheet carry-in path P1, there are disposed a carry-in roller24and a sheet discharge roller25. The sheet discharge roller25is configured to be rotatable in normal and reverse directions. Further, in the sheet carry-in path P1, there is disposed a path switching piece (not illustrated) for guiding the sheet to the second switchback conveying path SP2, and the piece is coupled to an operation means such as a solenoid. Further, the sheet carry-in path P1has, on the downstream side of the carry-in roller24, a stamp means for performing stamping on the sheet fed from the carry-in port23or a single-sheet punching unit28for punching the sheets fed from the carry-in port23one by one.

[Configuration of First Switchback Conveying Path SP1]

The first switchback conveying path SP1disposed on the downstream side (rear end portion of the device) of the sheet carry-in path P1as illustrated inFIG. 2is configured as described below. The sheet carry-in path P1is provided, at its exit end, with the sheet discharge roller25and a processing tray29on which the sheets fed by the sheet discharge roller25are stacked and supported. There is disposed, above the processing tray29, a normal/reverse rotation roller30capable of moving up and down between a position to come into contact with the sheet on the tray and a standby position spaced apart therefrom. The normal/reverse rotation roller30is controlled to rotate in a clockwise direction inFIG. 2when the sheet approaches the processing tray29to which the normal/reverse rotation roller30is coupled, and to rotate in a counterclockwise direction after a sheet rear end passing through the sheet discharge roller25enters the processing tray29. Thus, the first switchback conveying path SP1is positioned above the processing tray29.

Further, the first sheet discharge tray21is located downstream of the first switchback conveying path SP1and is configured to support a leading end of the sheet to be guided to the first switchback conveying path SP1and the second switchback conveying path SP2.

An end face stapler33is disposed at a rear end portion of the processing tray29in the sheet discharge direction. The illustrated end face stapler33staples a sheet bundle on the processing tray29at one or more positions of a rear end edge of the sheet bundle. The staple-bound sheet bundle is discharged onto the first sheet discharge tray21.

The first switchback conveying path SP1configured as described above aligns the sheets fed by the sheet discharge roller25on the processing tray29in the “(2) staple-binding mode” as described above, and the end face stapler33staples the sheet bundle at one or more portions of the rear end edge of this sheet bundle. In the “(1) print-out mode”, the sheet fed by the sheet discharge roller25is not subjected to the switchback, but conveyed along the processing tray29and discharged to the first sheet discharge tray21by a rotation of the normal/reverse rotation roller30in a clockwise direction inFIG. 2.

[Configuration of Second Switchback Conveying Path SP2]

The following describes a configuration of the second switchback conveying path SP2branched from the sheet carry-in path P1. The second switchback conveying path SP2is a conveying path for guiding a switchback-conveyed sheet. That is, in a state where the sheet is nipped by the sheet discharge roller25, rotation of the sheet discharge roller25is changed from the normal rotation to the reverse rotation, with the result that the sheet is switchback-conveyed along the switchback conveying path SP2. As illustrated inFIG. 2, the second switchback conveying path SP2is located in a substantially vertical direction inside the casing20. A conveying roller36is located at an inlet of the second switchback conveying path SP2, and an exit conveying roller37is located at an outlet of the second switchback conveying path SP2. A stacker section35constituting a second processing tray that aligns and temporarily stacks the sheets fed along the second switchback conveying path SP2is provided downstream of the second switchback conveying path SP2. The illustrated stacker section35includes a conveying guide that transfers the sheet. A saddle stitching stapler40and a folding roller45are arranged along the stacker section35. The configuration of these components will be sequentially described below.

The stacker section35is formed of a guide member that guides the sheet being conveyed. The stacker section35is configured such that the sheets are stacked and housed thereon. The illustrated stacker section35is connected to the second switchback conveying path SP2and located in a center portion of the casing20so as to extend in the substantially vertical direction. This allows the device to be compactly configured. The stacker section35is shaped to have an appropriate size to house maximum sized sheets. In particular, the illustrated stacker section35is curved or bent so as to project toward an area in which the saddle stitching stapler40and the folding roller45to be described later are arranged.

A switchback approaching path35ais connected to a conveying direction rear end of the stacker section35. The switchback approaching path35aoverlaps the outlet end of the second switchback conveying path SP2. This is to allow the leading end of a carried-in (succeeding) sheet fed from the exit conveying roller37on the second switchback conveying path SP2to overlap the rear end of the stacked (preceding) sheets supported on the stacker section35to ensure the page order of the stacked sheets. A leading end regulating member (hereinafter, referred to as stopper38) regulating a sheet leading end of the sheet in the conveying direction is located downstream of the stacker section35. The stopper38is supported by a guide rail and the like so as to be movable along the stacker section35. The stopper38is configured to be movable to a position where the sheet is carried in the stacker section35by means of a not illustrated shift means, a position where the sheet bundle is bound at a center thereof in the stacking direction, and a position where the sheet bundle is folded by the folding roller45. Further, an aligning means39for aligning the sheets is provided in the middle of the stacker section35in the sheet conveying direction. The aligning means39presses a side edge of the sheet for alignment every time the sheet is carried in.

The saddle stitching stapler40positioned above the stacker section35includes a driver unit41and a clincher unit42which are arranged opposite to each other with respect to the stacker section35. The driver unit41drives a staple into a sheet bundle. The clincher unit42bends leg portions of the driven staple in a direction facing each other. With this configuration, the sheet bundle is bound at a binding position X illustrated inFIG. 2corresponding to the half of a sheet length. The saddle stitching stapler40may perform the binding not only by using a metallic staple, but also by using a paper-made staple, by performing press-bonding (without use of the metallic or paper-made staple), or by forming a cut in the paper sheets (without use of the metallic or paper-made staple).

The following describes a configuration of the folding roller45. As illustrated inFIG. 2, the folding roller45for folding the sheet bundle and a folding blade46for inserting the sheet bundle into a nip position of the folding roller45are disposed at a folding position Y set on the downstream side of the above-described saddle stitching stapler40. As illustrated inFIGS. 3A to 3D, the folding roller45is constituted by an upper pressure contact roller45aand a lower pressure contact roller45bwhich are brought into pressure contact with each other. The upper and lower pressure contact rollers45aand45beach have a length slightly longer than the maximum width of the sheet. The folding roller pair45are biased in the pressure contact direction by a not illustrated compression spring. The folding roller pair45are each formed of a material, such as rubber, having a comparatively large friction coefficient.

Further, the folding blade46configured to be moved toward the pressure contact position of the folding roller pair45is disposed so as to be capable of advancing and retreating. After the sheet bundle is saddle-stitched by the saddle stitching stapler40, the folding blade46is moved to push the binding position between the folding roller pair45to cause the folding roller pair45to be rotated while pressed against each other, whereby the saddle-stitched sheet bundle is center-folded. In the middle of the above folding processing, the folding blade46is returned to its original position and waits for the next sheet bundle. A movement path along which the folding blade46is moved is illustrated as the folding position Y which coincides with the binding position X of the sheet bundle.

Hereinafter, a procedure of folding processing of the stacked sheet bundle or stacked and saddle-stitched sheet bundle will be described usingFIGS. 3A to 3D. The sheets are stopped by the stopper38and stacked as a sheet bundle. Then, the stopper38is moved upward to allow the saddle stitching stapler40to saddle-stitch the sheet bundle at about a center position of the sheet bundle in the sheet conveying direction. After the saddle stitching, the stopper38supporting the resultant sheet bundle is moved down and stopped at a position where the sheet binding position coincides with a folding position. This state is illustrated inFIG. 3A. This position coincides with the pressure contact position between the upper and lower pressure contact rollers45aand45bconstituting the folding roller45. Thereafter, the upper and lower pressure contact rollers45aand45bare rotated in the same direction by a not illustrated drive motor, and the folding blade46is moved so as to be pushed to the pressure contact position. This state is illustrated inFIG. 3B.

Then, as illustrated inFIG. 3C, the upper and lower pressure contact rollers45aand45bcontinue being rotated in the same direction, while the folding blade46is once stopped before the pressure contact position. Then, the folding blade46is retracted in a returning direction. Afterward, when the upper and lower pressure contact rollers45aand45bare further rotated in the same direction, a folded sheet bundle BS to be folded is folded while forming a certain loop BL as illustrated inFIG. 3D. In this state, there are formed a folding loop leading end BL1which is a fold formed as a result of pushing of the folding blade46, an upper loop BL2swelling upward with the folding loop leading end BL1as a center, a lower loop BL3swelling downward, and a loop base end portion BL4that presses the sheets so as to maintain the loop, and the folding operation is once stopped.

The loop at the fold is generated due to action of force for the sheet bundle to be opened outward. Thus, the larger the number of the sheet bundle BS to be folded, the greater the force for the sheet bundle itself to be opened and spread. Accordingly, if no countermeasure is taken, a discharged sheet bundle is opened. So, in the present invention, sheet pressing to be described below is performed.

The folding roller45may be used for detecting a thickness of the sheet bundle BS to be folded. That is, by measuring a difference between a distance between axes of the upper and lower pressure contact rollers45aand45bin a state where the sheet bundle BS is not inserted and a distance therebetween in a state where the sheet bundle BS is inserted, the thickness of the sheet bundle BS can be detected.

Hereinafter, the sheet pressing device constituting a part of the sheet processing device according to the present invention will be described. The sheet pressing device50is a device for preventing the folded sheet bundle BS from being opened. First, a configuration of the sheet pressing device50will be described with reference toFIG. 4(perspective view),FIG. 5(cross-sectional view), andFIG. 6(front view viewed as the folding roller side), followed by description of operation thereof with reference toFIGS. 7 to 15andFIGS. 16A to 16E.

As illustrated inFIG. 2, the sheet pressing device50is disposed so as to cross a folded sheet conveying path PB installed downstream of the folding roller45. More in detail, the sheet pressing device50performs pressing for the sheet bundle folded in two by the folding roller45. The sheet pressing device50faces the fold of the folded sheet bundle BS having the fold in the sheet width direction and a certain loop.

The sheet pressing device50illustrated inFIG. 2is installed between the folding roller45and a bundle discharge roller49that discharges the sheet bundle BS outside the device; alternatively however, the sheet pressing device50may be disposed downstream of the bundle discharge roller49as long as it crosses the folded sheet conveying path PB.

As illustrated inFIG. 4, in the sheet pressing device50, a connecting angle55connecting a right side plate53and a left side plate54disposed at one side of the device is used to constitute the entire frame of the device. A pressing roller unit56is disposed between the right side plate53and the left side plate54so as to be reciprocated therebetween. The pressing roller unit56configured to be reciprocated is slidably moved along an upper guide rail57and a lower guide rail58extending between the right side plate53and the left side plate54. More specifically, the pressing roller unit56is supported such that an upper slide block60attached to an upper portion of the pressing roller unit56is slid along the upper guide rail57and a lower slide block61attached to a lower portion of the pressing roller unit56is slid along the lower guide rail58.

A moving belt65is provided above the pressing roller unit56so as to be stretched between the right side plate53and the left side plate54. A right pulley63that winds the moving belt65is provided at the right side plate53side, and a left pulley64that winds the moving belt65is provided at the left side plate54side. One end of the moving belt65is fixed to a belt fixing portion65bat an upper end of the pressing roller unit56. Thus, when the moving belt65is moved to move the belt fixing portion65bfrom a device back side (right side) to a device front side (left side), the pressing roller unit56is moved from the device back side (right side) to the device front side (left side) along the upper guide rail57and the lower guide rail58. When the moving belt65is moved in the opposite direction, the belt fixing portion65bis also moved in the opposite direction, which moves the pressing roller unit56in the opposite direction. Thus, the pressing roller unit56is a moving member that is moved by means of the moving belt65and the like.

The left pulley64that winds the moving belt65is mounted to a motor gear unit68provided on the left side plate54and connected to a drive motor69as a drive member configured to be rotatable in normal and reverse directions through the motor gear unit68. Rotation drive of the drive motor69is transmitted from a motor output gear67to a transmission gear66provided in the motor gear unit68, and then to the left pulley64of the moving belt65. Thus, selecting a rotating direction of the drive motor69allows the pressing roller unit56to be moved selectively in the directions from the device back side (right side) to the device front side (left side) and from the device front side (left side) to the device back side (right side).

The following describes the pressing roller unit56configured to be reciprocated left and right. As illustrated inFIG. 4, which is a view as viewed from the bundle discharge roller49side, upper pressing rollers71a,71b(collectively referred to as an upper pressing roller71) and lower pressing rollers72a,72b(collectively referred to as a lower pressing roller72) as a pair of upper and lower sheet pressing members (corresponding to a pressing roller70) are disposed on one side surface of a pressing base plate62. Further, there is provided a cam member80as an interval regulating member for regulating an interval between the upper pressing roller71and the lower pressing roller72. Details of the cam member80will be described later.

As illustrated inFIGS. 5 and 6, vertical movement of the upper and lower pressing rollers71and72is achieved by an upper pressing roller support block73and a lower pressing roller support block74which are configured to vertically slid along three roller support block slide rails77extending between a roller support upper block75and a roller support lower block76. Further, the upper pressing roller support block73is biased downward inFIG. 6with a constant biasing force by an upper spring90interposed between the upper pressing roller support block73and the roller support upper block75. Similarly, the lower pressing roller support block74is biased upward inFIG. 6with a constant biasing force by a lower spring91interposed between the lower pressing roller support block74and the roller support lower block76. Thus, the upper and lower pressing roller support blocks73and74are biased in a direction facing each other with a constant biasing force. The roller support upper and lower blocks75and76serve also as spring holders of the upper and lower springs90and91, respectively.

As illustrated inFIG. 5, the upper pressing roller71is supported by the upper pressing roller support block73by means of an upper pressing roller support shaft73asuch that a longitudinal direction thereof coincides with a folded sheet conveying direction (direction crossing a fold direction). Thus, the upper pressing roller71can be rotated about the support shaft73adisposed in the direction (direction same as the sheet conveying direction) crossing the fold direction. Further, the upper pressing roller71is constructed of two series of the upstream side upper pressing roller71aand downstream side upper pressing roller71barranged in the folded sheet conveying direction. The lower pressing roller72has the same configuration as that of the upper pressing roller71.

The pressing roller70need not include the two series of pressing rollers but may be constructed of a single pressing roller.

As described above, there is provided the cam member80as the interval regulating member for regulating the interval between the upper and lower pressing rollers71and72. A configuration of the cam member80is as follows. Referring back toFIG. 4, an upper regulating pin82of the upper pressing roller support block73supporting the upper pressing roller71and a lower regulating pin83of the lower pressing roller support block74supporting the lower pressing roller72each protrude from the pressing base plate62to a back surface side thereof. Positions of the upper and lower regulating pins82and83are retained by cam surfaces of the cam member80against the elastic force of the upper and lower springs90and91as the elastic member. In the present embodiment, as the elastic force of each of the upper and lower springs90and91, about 4 kg is applied when the interval between the upper and lower springs90and91is 0 mm.

Hereinafter, with reference toFIGS. 4, 5, and 6, the cam member80as an interval setting means for setting the interval between the upper and lower pressing rollers71and72of the pressing roller70as the sheet pressing member by regulating the upper and lower regulating pins82and83. The cam member80is fixed to a cam drive shaft81as a rotation axis to be described later. As illustrated inFIGS. 4 and 5, the cam drive shaft81is rotated by a cam drive motor84operated at a reduced speed by a gear unit, thereby allowing the cam member80to be rotated. The cam member80has cam surfaces that regulate the upper and lower regulating pins82and83, respectively.

Referring toFIG. 9, the cam member80has first separated cam surfaces85that regulate the upper and lower regulating pins82and83at the largest interval, second separated cam surfaces86an interval between which is smaller than that between the first separated cam surfaces85by a predetermined value, and pressure contact cam surfaces87that release a position-regulated state of the upper and lower regulating pins82and83that bring the upper and lower pressing rollers71and72into a pressure contact state. More specifically, the cam member80has, as the first separated cam surfaces85, a first separated upper cam surface85aand a first separated lower cam surface85bwhich are point-symmetrical with respect to the cam drive shaft81. Further, the cam member80has, as the second separated cam surfaces86, a second separated upper cam surface86aand a second separated lower cam surface86b. Further, the cam member80has, as the pressure contact cam surfaces87, a pressure contact upper cam surface87aand a pressure contact lower cam surface87b.

As described above, each of the upper and lower cam surface pairs are point-symmetrical to each other. That is, a shape of the cam member80before rotation and that of the cam member80after rotation by 180° about the cam drive shaft81are the same as each other. This is for making the upper and lower pressing rollers71and72being moved by substantially the same distance with the cam drive shaft81as a rotation center axis by rotation of the cam member80by a predetermined amount. This allows the upper and lower pressing rollers71and72(pressing roller70) to press the folded sheet bundle BS substantially uniformly from both sides in the thickness direction of the fold. Thus, the upper and lower pressing rollers71and72constitute a sheet pressing member that presses the folded sheet bundle.

As described above, the upper and lower pressing rollers71and72as the sheet pressing member of the present invention can be moved both in the sheet fold direction which is the left-right width direction of the sheet to be conveyed between the left and right side plates53and54ofFIG. 4and the fold thickness direction crossing the sheet fold direction. Further, the rotatable configuration of the cam member80allows the upper and lower pressing rollers71and72to be substantially equally moved in the vertical direction, thereby allowing the interval therebetween to be reduced stepwise. Further, it is possible to bring the upper and lower pressing rollers71and72into pressure contact with each other.

[Operation of Sheet Pressing Device]

Hereinafter, carry-in of the folded sheet bundle BS to the sheet pressing device50and stepwise pressing operation will be described with reference toFIGS. 7 to 15.FIGS. 7 to 9illustrate a state where the upper and lower pressing rollers71and72(pressing roller70) override one end portion of the folded sheet bundle BS, move along the fold, and pass through the other end portion thereof to perform a first-step pressing at the largest interval.FIGS. 10 to 12illustrate a state where the upper and lower pressing rollers71and72(pressing roller70) move along the fold of the folded sheet bundle BS to perform a second-step pressing at a reduced interval.FIGS. 13 to 15illustrate a state where the upper and lower pressing rollers71and72(pressing roller70) move along the fold of the folded sheet bundle BS to press the fold in a pressure contact state.

First, the first-step pressing operation for the folded sheet bundle BS will be described with reference toFIGS. 7 to 9. In the perspective view ofFIG. 7, the pressing roller unit56situated at the home position on the right side plate53side is moved toward the left side plate54along the fold of the folded sheet bundle BS. At the home position, prior to the movement of the pressing roller unit56, the cam drive motor84is driven so as to make the cam member80illustrated inFIGS. 7 to 9regulate the interval between the upper and lower regulating pins82and83with the first separated cam surfaces85. This drive state is monitored by a not illustrated cam position detection sensor and a not illustrated encoder provided inside the cam drive motor84. The sheet bundle BS is tow-folded by the folding roller45to form a loop at a position overlapping the upper and lower pressing rollers71and72as illustrated inFIG. 8. After the loop of the folded sheet bundle BS is formed, the pressing roller unit56is moved to the left while creating a fold as illustrated inFIG. 7.

In the present embodiment, a size of the maximum loop is set to about 22 mm, and the interval between the upper and lower pressing rollers71and72in the first step is set to about 14 mm, so that the upper and lower pressing rollers71and72overlap the upper and lower portions of the loop, respectively, each by a length of about 4 mm. Thus, the upper and lower pressing rollers71and72override the end portion of the folded sheet bundle BS in the width direction and move along the fold while pressing the loop of the folded sheet bundle BS. In the one-way movement along the fold, the interval between the upper and lower pressing rollers71and72is regulated by the first separated cam surfaces85of the cam member80so as not to become smaller. As a result of this movement, a first fold line100is created along the fold of the folded sheet bundle BS. This point will be described in detail later usingFIGS. 17A to 17CandFIG. 18.

Next, the second-step pressing operation for the folded sheet bundle BS will be described with reference toFIGS. 10 to 12. In the perspective view ofFIG. 10, the pressing roller unit56moved from the right side plate53to the left side plate54is returned toward the right side plate53in a direction indicated by an illustrated arrow and situated at a center position between the left and right side plates54and53. At the position on the left side plate54side, prior to the return movement of the pressing roller unit56, the cam drive motor84is driven so as to make the cam member80regulate the interval between the upper and lower regulating pins82and83with the second separated cam surfaces86. This drive state is monitored by a not illustrated cam position detection sensor and a not illustrated encoder provided inside the cam drive motor84. The sheet bundle BS retains the loop at a position overlapping the upper and lower pressing rollers71and72in the second step. The pressing roller unit56is moved to the right while creating a second-step fold on the loop of the folded sheet bundle BS as illustrated inFIG. 10.

In the present embodiment, the interval between the upper and lower pressing rollers71and72in the first step is set to about 14 mm. In the second step, the interval is set to about 7 mm. Thus, the upper and lower pressing rollers71and72overlap the respective upper and lower portions of the folded sheet bundle that has been pressed in the first step, each by a length of about 3.5 mm. Thus, as in the case of the first step, the upper and lower pressing rollers71and72override the end portion of the folded sheet bundle BS in the width direction and move along the fold while pressing the loop of the folded sheet bundle BS. In the movement along the fold, the interval between the upper and lower pressing rollers71and72is regulated by the second separated cam surfaces86of the cam member80so as not to become smaller. As a result of this movement, a second fold line101to be described later is created along the fold of the folded sheet bundle BS toward the right side plate53side.

Finally, the third-step pressing operation for the folded sheet bundle BS will be described with reference toFIGS. 13 to 15. In the perspective view ofFIG. 13, the pressing roller unit56moved from the left side plate54to the right side plate53is returned toward the left side plate54and situated at the center position between the left and right side plates54and53. At the home position on the right side plate53side, prior to the return movement of the pressing roller unit56, the cam drive motor84is driven so as to bring the pressure contact surfaces87of the cam member80into pressure contact with the upper and lower regulating pins82and83, respectively. This drive state is monitored by a not illustrated cam position detection sensor and a not illustrated encoder provided inside the cam drive motor84.

In the first and second steps, the cam member80uses the first separated cam surfaces85and the second separated cam surfaces86, respectively, to regulate the interval between the upper and lower regulating pins82and83so as not to reduce the interval any more. On the other hand, in the final step, a gap is provided between the pressure contact surfaces87and respective upper and lower regulating pins82and83. This means that, if the folded sheet bundle BS is not inserted between the upper and lower pressing rollers71and72, the upper and lower pressing rollers71and72are brought into pressure contact with each other by the upper and lower springs90and91. Thus, the upper and lower pressing rollers71and72move along the fold of the folded sheet bundle BS while pressing the fold in the thickness direction of the fold without being regulated by the cam member80in terms of the interval therebetween. That is, the fold created by the folding roller is pressed by the pressing roller70once again.

In the present embodiment, the interval between the upper and lower pressing rollers71and72in the second step is set to about 7 mm. In the final step, the interval between the upper and lower pressing rollers71and72is set so as to allow the fold of the folded sheet bundle BS to be pressed harder in the thickness direction thereof. Thus, the upper and lower pressing rollers71and72override, along the fold created by the folding roller45, the end portion of the folded sheet bundle BS in the width direction by an amount corresponding to the thickness of the folded sheet bundle BS and move along the fold while pressing the fold. That is, as described later, in the final step, the pressing roller70presses a final fold line102corresponding to the fold created by the folding roller45.

[Movement of Sheet Pressing Unit]

The following describes a pressing procedure of the pressing roller unit56and a standby position after the pressing operation with reference toFIGS. 16A to 16Eillustrating the processes ofFIGS. 7 to 15in a simplified manner.

FIG. 16Aillustrates a state where the pressing roller unit56in the first step illustrated inFIGS. 7 to 9moves from the home position on the right side in the figure toward a returning position on the left side with the interval between the upper and lower pressing rollers71and72set to a first interval L1(in the present embodiment, about 14 mm). By the first movement, a first-step fold line is created on the loop BL of the folded sheet bundle BS.

FIG. 16Billustrates the second-step pressing operation ofFIGS. 10 to 12. At the returning position on the left side in the figure, the interval between the upper and lower pressing rollers71and72is changed to a second interval L2(in the present embodiment, about 7 mm), and the upper and lower pressing rollers71and72move from the returning position on the left side in the figure to the home position on the right side to press the fold of the folded sheet bundle BS.

FIG. 16Cillustrates the final-stage pressing operation ofFIGS. 13 to 15. At the home position on the right side in the figure, the interval between the upper and lower pressing rollers71and72is set to an interval L3(in the present embodiment, 0 mm, i.e., free from regulation) to bring the rollers71and72into a pressure contact state. In this state, the pressing roller unit56is moved from the home position on the right side in the figure toward the returning position on the left side. After completion of the three-step pressing operation for the folded sheet bundle BS by the above movement, the folded sheet bundle BS is discharged to the second sheet discharge tray22by rotation of the folding roller45and the bundle discharge roller49.

InFIG. 16D, after the discharge of the folded sheet bundle BS, the pressing roller unit56is moved from the returning position on the left side toward the home position on the right side with the interval between the upper and lower pressing rollers71and72kept to L3(=0, i.e., free from regulation). After this movement, the cam member80is driven so as to set the interval between the upper and lower pressing rollers71and72to the first interval L1in order for the pressing roller unit56to receive a new folded sheet bundle BS from the folding roller45. In this state, the pressing roller unit56waits for carry-in of the new folded sheet bundle BS. The above series of the pressing operation (FIGS. 16A to 16D) is repeated until the number of the folded sheet bundles reaches a specified value.

FIG. 16Eillustrates a modification of the configuration illustrated inFIG. 16D. That is, inFIG. 16D, the pressing roller unit56is returned to the home position on the right side with the upper and lower pressing rollers71and72kept in a pressure contact state, and then the pressing rollers71and72are separated from each other by the interval L1at the home position. Alternatively, however, when the succeeding folded sheet bundle BS is carried in rapidly, the interval between the upper and lower pressing rollers71and72may be changed from L3(pressure contact state) to L1at the returning position before the pressing roller unit56starts being returned to the home position. In this case, the pressing roller unit56that performs the pressing operation for the loop of the folded sheet bundle BS moves in a reverse direction to that illustrated inFIGS. 16A to 16C.

Further, although not illustrated particularly, the following procedure can be adopted. That is, as illustrated inFIG. 16D, the pressure contact state between the upper and lower pressing rollers71and72is released, that is, the interval between the pressing rollers71and72is changed from L3to L1after the pressing roller unit56has been returned to the home position on the right side; however, the interval may be changed from L3(pressure contact state) to L1while the pressing roller unit56is being returned from the returning position on the left side to the home position on the right side. In this case, the pressing roller unit56that performs the pressing operation for the loop of the folded sheet bundle BS moves in a direction same as that illustrated inFIGS. 16A to 16C, simplifying a control method.

As described above, in the present embodiment, the three-step pressing operation is performed for the two-folded sheet bundle BS by the pressing roller unit56. The following describes the folded sheet bundle BS in a state after being pressed and discharged with reference toFIGS. 17 and 18.

As described hereinbefore, the upper and lower pressing rollers71and72(pressing roller70) as the sheet bundle pressing member of the present invention are moved, along the fold direction, on a part of the folded sheet bundle BS where the fold is created by the folding roller45and thus the loop is generated while pressing the folded sheet bundle BS in a thickness direction (vertical direction crossing, at the fold of the folded sheet bundle BS, a conveying direction of the folded sheet bundle BS) of the fold to thereby create a plurality of folds. As described above, in the first step, the interval between the upper and lower pressing rollers71and72is set to a value (in the present embodiments, about 14 mm relative to the loop size (height) of 22 mm) slightly smaller than the size of the folded sheet bundle loop BL, and the upper and lower pressing rollers71and72are moved along the fold created by the folding roller45to thereby create the first-step fold. InFIGS. 17A to 17CandFIG. 18, the first-step fold is illustrated as a first fold line100represented by a light line on the folded sheet bundle BS.

In the second step, the upper and lower pressing rollers71and72, the interval between which is set to a value (in the present embodiments, about 7 mm) slightly smaller than the size of the loop pressed in the first step, are moved along the fold created by the folding roller45to thereby create the second-step fold. InFIGS. 17B, 17CandFIG. 18, the second-step fold is illustrated as a second fold line101represented by a light line on the folded sheet bundle BS.

In the final step, the upper and lower pressing rollers71and72are brought into pressure contact with each other by the elastic force of the upper and lower springs90and91. In this final step, unlike the first and second steps, no interval is provided between the upper and lower pressing rollers71and72(in the present embodiments, interval is set to 0).

Thus, in the final step, the upper and lower pressing rollers71and72are moved along the fold while pressing the position corresponding to the thickness of the folded sheet bundle BS that has been pressed in the first and second steps. The fold created in the final step is illustrated as a final fold line102represented by a comparatively dark line on the folded sheet bundle BS.

At end portions of the folded sheet bundle BS in the width direction, end portion folds103created when the folding roller45and upper and lower pressing rollers71and72, which are brought into a pressure contact state, override the folded sheet bundle BS are formed.

As described above, the folds are created by the upper and lower pressing rollers71and72whose interval can be variously changed. As a result, a folding direction is directed to a closing direction (direction of a line extending in the conveying direction that passes the fold) of the folded sheet bundle BS at the respective positions of the first fold line100(indicated by the light line) of the first step, the second fold line101(indicated by the light line) of the second step, and the final fold line102(indicated by the comparatively dark line) of the final step generated in accordance with the thickness of the folded sheet bundle BS. With this configuration, it is possible to prevent the folded sheet bundle BS from being opened after discharge of the folded sheet bundle BS to thereby prevent degradation of aligning property and accumulating property.

Control configuration of the sheet processing device B provided with the thus described sheet pressing device50and the image forming device A including the sheet processing device B will be described based on a block diagram ofFIG. 19. An image forming device controller110having an image forming means inputs desired processing through user's operation made to an input means provided on a control panel. This input controls a sheet processing device controller115of the sheet processing device B based on a mode setting means.

As described above, in the sheet processing device B of the present invention, the following four modes can be specified: (1) “print-out mode”, (2) “staple-binding mode”, (3) “saddle stitching and folding mode”, and (4) “folded sheet pressing mode”.

The sheet processing device B includes the sheet processing device controller115that is made operable in one of the above four modes, a ROM that stores an operation program, and a RAM that stores control data. The sheet processing device controller115includes a sheet conveying controller116that controls sheet conveyance in the device, a single-sheet punching controller117that applies punching, one by one, the sheets by means of a single-sheet punching unit28, a processing tray controller118that performs control of accumulating the sheets on the processing tray29, and an end face binding controller119that binds the end face side of the sheets accumulated in a bundle and discharges the bound sheet bundle.

The saddle stitching or the center-folding of the sheet at about a half position thereof in the sheet conveying direction is controlled by a stacker section controller120that accumulates the sheet bundle in the sheet stacker section35. The stacker section controller120uses the stopper38or the aligning means39that regulates the leading end of the sheets carried in, one by one, to the stacker section35to generate an aligned sheet bundle. The sheet processing device controller115further includes a saddle stitching controller121that controls the saddle stitching stapler40to drive a staple or the like to a center portion of the sheet bundle and a sheet folding controller122that controls the folding blade46to push the saddle-stitched sheet bundle into the folding roller45to fold the sheet bundle.

The sheet processing device controller115further includes a folded sheet pressing controller123that controls the sheet pressing device according to the thus described “folded sheet pressing mode”. The folded sheet bundle BS that has been pressed is discharged and accumulated in the second sheet discharge tray22under control of a center-folded sheet discharge controller124that controls the folding roller45serving also as a bundle conveying roller and the bundle discharge roller49.

The folded sheet pressing control related especially to the present invention has been described based on the description of the respective mechanisms and using operation state explanatory views ofFIGS. 7 to 15andFIG. 16, so descriptions thereof will be omitted. The sheet pressing device50is controlled so as to execute the sheet pressing based on the contents described.

The present invention in its preferred embodiments provides the following effects.

(1) There is provided, according to the above embodiment, a sheet processing device B that presses a folded sheet bundle, the sheet processing device B including a pair of pressing rollers70as a pressing member that press a fold of the folded sheet bundle in a thickness direction of the fold, a pressing roller unit56as a moving member that moves the pressing roller pair70along the fold of the folded sheet bundle, and a cam member80as an interval regulating member that regulates an interval between the pressing roller pair70, wherein when the pressing roller unit56is moved along the fold of the folded sheet bundle to press the fold in the fold thickness direction, the cam member80reduces stepwise the interval between the pressing roller pair70in accordance with a moving direction of the pressing roller unit56.

With this configuration, in the first pressing operation performed in the thickness direction of the fold, the pressing roller pair70is moved in a sheet width direction with a predetermined interval provided therebetween to create a fold, and in the next pressing operation, the pressing roller pair70is moved in the sheet width direction with the interval therebetween reduced to create a new fold, whereby the fold of the folded sheet bundle is directed inward. Thus, the sheet bundle itself is directed to its binding direction, thereby preventing the folded sheet bundle from being opened after the pressing, which allows more sheet bundles to be accumulated.

(2) In the sheet processing device of (1), the pressing roller pair70is a pair of rotatable rollers having a support shaft in a direction crossing the fold direction.

With this configuration, the pressing roller pair70can be rotated in the moving direction, so that it can override the fold from a sheet end portion and press the fold without catch to thereby perform smooth sheet pressing operation.

(3) In the sheet processing device of (1), the pair of pressing rollers70are biased against each other by the upper and lower springs90and91in a direction facing each other and are position-regulated by the cam member80against the biasing force.

With this configuration, when pressing folded sheet bundle formed by rigid sheets, the pressing roller pair70can set the fold by being moved upward with downward movement thereof regulated by the cam member80, whereby the fold can be set at different positions.

(4) In the sheet processing device of (3), the cam member80is rotated in accordance with the moving direction of the pressing roller unit56to reduce stepwise the interval between the pair of pressing rollers70.

With this configuration, the interval can be set by the cam member80, thereby facilitating position setting and thereby making it easy to set a position of the pressing roller pair70.

(5) In the sheet processing device of (4), the cam member80can be rotated about a cam drive shaft81serving as a center axis of the cam member80and has a shape point-symmetrical with respect to the center axis so as to equally move the pressing roller pair70.

With this configuration, the cam member80has a symmetrical shape, so that the pair of pressing rollers70equally approach each other in the sheet thickness direction. Thus, the fold lines created by the pair of pressing rollers70are formed at positions substantially equally distant from the sheet fold position, whereby a folded booklet having a good appearance can be created.

(6) In the sheet processing device of (5), in the final step of the movement of the pressing roller unit56along the fold of the folded sheet bundle, the position regulation for the pressing roller pair70by the cam member80is released to cause the folded sheet bundle to be pressed by the pressing roller pair70biased by the upper and lower springs90and91.

With this configuration, when the pair of pressing rollers are moved in the final step, they are not position-regulated by the cam member80, so that the pressing roller unit56is moved along the fold while pressing the folded sheet bundle with spring force of the upper and lower springs90and91, thereby reliably pressing the fold of the folded sheet bundle.

(7) In the sheet processing device of (2), one-way movement of the pressing roller unit56along the fold of the folded sheet bundle is continued from when the pressing roller pair70overrides one end portion of the folded sheet bundle in the fold direction until when the pressing roller pair70passes through the other end portion of the folded sheet bundle.

With this configuration, the pressing roller unit56can create the folds sequentially while being moved by a distance longer than the width of the folded sheet bundle, whereby a folded booklet having improved pressing effect can be created.

(8) There is provided, according to the above embodiment, a sheet processing device that presses a folded sheet bundle, the sheet processing device including a stacker section35that accumulates sheets as a sheet bundle, a folding roller45that folds the accumulated sheet bundle, a pair of pressing rollers70that press a fold of the sheet bundle folded by the folding roller45in a thickness direction of the fold, a pressing roller unit56that moves the pressing roller pair70along the fold of the folded sheet bundle, a drive belt65and a drive motor69that reciprocate the pressing roller unit56by a distance longer than a width of the folded sheet bundle in the fold direction, upper and lower springs90and91that bias the pair of pressing rollers70in their approaching direction, and a movably configured cam member80that regulates, against the biasing force of the upper and lower springs90and91, an interval between the pair of the pressing rollers70at a plurality of levels, wherein the folded sheet bundle is pressed in a thickness direction of the fold with the cam member80moved in accordance with a moving direction of the pressing roller unit56driven by the drive belt65and the drive motor69so as to reduce the interval between the pair of pressing rollers70.

With this configuration, in the first pressing operation performed in the thickness direction of the fold, the pressing roller pair70is moved in a sheet width direction with a predetermined interval provided therebetween to create a fold, and in the next pressing operation, the pressing roller pair70is moved in the sheet width direction with the interval therebetween reduced to create a new fold, whereby the fold of the folded sheet bundle is directed inward. Thus, the sheet bundle itself is directed to its binding direction, thereby preventing the folded sheet bundle from being opened after the pressing, which enhances the aligning property of the sheet bundle and allows more sheet bundles to be accumulated.

(9) There is provided, according to the embodiment, an image forming device A including an image forming means for forming an image on a sheet and a sheet processing device that applies predetermined sheet processing to the image-formed sheet from the image forming means, wherein the sheet processing device is the sheet processing device B described in (1) to (8).

With this configuration, there can be provided the image forming device A having the sheet processing device B capable of providing working effects described in the above respective paragraphs.

(10) There is provided, according to the embodiment, a sheet pressing method of a sheet pressing device including a pair of pressing rollers70that press a fold of a folded sheet bundle in a thickness direction of the fold, a pressing roller unit56that moves the pressing roller pair70along the fold of the folded sheet bundle, and a cam member80that regulates an interval between the pressing roller pair70, wherein, in a first movement of the pressing roller unit56along the fold of the folded sheet bundle, the folded sheet bundle is pressed in the thickness direction of the fold with the interval between the pair of pressing rollers70set to a comparatively large first interval, and in the next movement of the pressing roller unit56, the folded sheet bundle is pressed in the thickness direction of the fold with the interval between the pair of pressing rollers70set to an interval smaller than the first interval.

With this configuration, the interval between the pair of pressing rollers70is reduced stepwise at every movement of the pressing roller unit56along the fold of the folded sheet bundle, so that the sheet bundle itself is directed to its binding direction, thereby preventing the folded sheet bundle from being opened after the pressing, which allows more sheet bundles to be accumulated.

In the description of the effects of the embodiments, reference numerals are given to constituent elements recited in the claims so as to clarify a correspondence relationship between the description of “Detailed Description” and the description of “What is Claimed is”.

Further, it should be appreciated that the present invention is not limited to the present embodiment, and various modifications may be made thereto. Further, all technical matters included in the technical ideas set forth in the claims should be covered by the present invention. While the invention has been described based on a preferred embodiment, those skilled in the art can realize various substitutions, corrections, modifications, or improvements may be made from the content disclosed in the specification by a person skilled in the art, which are included in the scope defined by the appended claims.

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2014-133797, filed Jun. 30, 2014, the entire contents of which are incorporated herein by reference.