Patent ID: 12240726

DESCRIPTION OF EMBODIMENTS

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.

The present disclosure is configured so that a driving force to sandwich and reverse a conveyor provided in the original conveyance path is supplied by a single driving source. A folding of a sheet-shaped medium is performed with the driving force from the single drive source. Hereinafter, embodiments of the present disclosure are described with reference to the drawings.

Referring toFIG.1, a description is given of an image forming apparatus according to an embodiment of the present disclosure. As illustrated inFIG.1, a printer1serving as the image forming apparatus according to an embodiment of the present disclosure basically includes an image forming unit200and a sheet processing unit100. The sheet processing unit100is one of a sheet processing device and a sheet processing apparatus according to embodiments of the present disclosure. Details of the sheet processing unit100are described later.

The image forming unit200conveys a sheet P from a sheet storage unit accommodating the sheet P as a sheet-shaped medium to an image forming section that forms an image on the sheet P. The image forming unit200includes a conveyance mechanism that discharges the sheet P to the sheet processing unit100after an image formation. As illustrated inFIG.1, the printer1has, for example, a configuration that discharges the sheet P from right to left toward an operation panel301serving as an operation interface.

Hereinafter, embodiments of the present disclosure are premised on the configuration illustrated inFIG.1. In addition to the configuration illustrated inFIG.1, as illustrated inFIG.28, a printer1serving as an image forming apparatus according to an embodiment of the present disclosure may have a configuration that discharges the sheet P from left to right toward the operation panel301. Further, as illustrated inFIG.29, a printer1serving as an image forming apparatus according to an embodiment of the present disclosure may have a configuration that discharges the sheet P from the back side to the front side toward the operation panel301.

In any of the above-described embodiments, the sheet processing unit100is disposed at a discharge port where the sheet P is discharged from the image forming unit200, thus allowing the sheet P to be folded and discharged. The sheet processing unit100may be detachably attached with respect to the image forming unit200or may be incorporated as a part of the image forming unit200.

FIG.30is a schematic diagram illustrating a configuration of an image forming system1000according to an embodiment of the present disclosure. InFIG.30, the image forming system1000according to the present embodiment basically includes an image forming apparatus1010and a folding processing apparatus1020serving as the sheet processing apparatus. A sheet P on which an image is formed by the image forming apparatus1010is conveyed to the folding processing apparatus1020. The folding processing apparatus1020performs a predetermined sheet folding operation to the sheet P and discharges the sheet P.

FIG.2illustrates an outline of a conveyance mechanism and a folding processing mechanism provided in the sheet processing unit100. As illustrated inFIG.2, the sheet processing unit100includes a first conveyor110, a second conveyor120, a first folding roller section130, a second folding roller section140, a discharge roller section150, a first sheet detector160, and a second sheet detector170. The sheet processing unit100includes a plurality of rollers and rotates a plurality of roller pairs including these rollers to fold a sheet P.

A conveyance path provided in the sheet processing unit100is distinguishable into a plurality of conveyance paths for convenience. A first conveyance path401is a conveyance path downstream from the first conveyor110and upstream from the second conveyor120in the conveyance direction of the sheet P to bend the sheet P when the sheet processing unit100forms a first crease on the sheet P. A second conveyance path402is a conveyance path downstream from the second conveyor120and includes a configuration of detecting an inversion timing of the sheet P when the sheet P is folded. A third conveyance path403is a conveyance path that branches from the first conveyance path401. The sheet P on which the first crease is formed is conveyed to the third conveyance path403. A fourth conveyance path404is a conveyance path that conveys the sheet P on which a second folding process has been performed in the first folding roller section130and includes a configuration of performing an additional-folding process.

The first conveyor110serving as a first conveying roller pair is disposed on the upstream side of the sheet processing unit100and disposed at a position to receive the sheet P discharged from the image forming unit200. The first conveyor110includes a first conveying drive roller111and a first conveying driven roller112. The first conveying drive roller111is a drive roller that rotates by a driving force from a drive motor180(serving as a driving force supply source). The first conveying driven roller112is a driven roller that rotates according to the rotation of the first conveying drive roller111.

The first conveying roller pair including the first conveying drive roller111and the first conveying driven roller112nips the sheet P. The first conveying roller pair rotates by the driving force from the drive motor180to convey the sheet P. The rotation direction of the first conveying drive roller111is a direction to move the sheet P from the upstream side to the downstream side in the conveyance direction defined as a direction in which the sheet P is folded and discharged. The first conveyor110corresponds to an upstream conveying roller pair disposed on the upstream side in the conveyance direction.

The second conveyor120(serving as a second conveying roller) pair is disposed downstream from the first conveyor110in the conveyance direction in the sheet processing unit100and conveys the sheet P together with the first conveyor110in the conveyance direction. The second conveyor120conveys a downstream portion of the sheet P in reverse toward the upstream side in the conveyance direction to form a bend for the folding process in the sheet P.

Hereinafter, the rotation of each roller to convey the sheet P in the conveyance direction illustrated inFIG.2is referred to as “forward rotation” or “rotate forward”. The rotation of each roller to convey the sheet P in the direction opposite to the conveyance direction is referred to as “reverse rotation” or “rotate in reverse”. The forward rotation corresponds to rotation in a first direction, and the reverse rotation corresponds to rotation in a second direction.

The second conveyor120includes a second conveying drive roller121and a second conveying driven roller122. The second conveying drive roller121is a drive roller that rotates by a driving force from the drive motor180. The second conveying driven roller122is a driven roller that rotates according to the rotation of the second conveying drive roller121.

The second conveying roller pair including the second conveying drive roller121and the second conveying driven roller122nips the sheet P. The second conveying roller pair rotates by the driving force from the drive motor180to convey the sheet P. The second conveying drive roller121rotates in two directions, that is, a direction to move the sheet P in the conveyance direction and a direction to reverse a downstream portion of the sheet P to the upstream side. The second conveyor120corresponds to a downstream conveying roller pair disposed downstream from the first conveyor110in the conveyance direction defined as a direction in which the sheet P is folded and discharged.

The first folding roller section130is disposed between the first conveyor110serving as the upstream conveying roller pair and the second conveyor120serving as the downstream conveying roller pair. The first folding roller section130serving as a third roller pair includes a first folding roller pair and a second folding roller pair. The first folding roller pair includes the second conveying drive roller121and a first folding roller131. The second folding roller pair includes the second conveying drive roller121and a second folding roller132. The first folding roller131and the second folding roller132are driven rollers that are rotated by the rotation of the second conveying drive roller121.

The second conveying drive roller121is rotated in a predetermined direction by the driving force from the drive motor180, with the first folding roller pair nipping the sheet P, to form the first crease on the sheet P. The sheet P on which the first crease is formed is conveyed to the third conveyance path403. The second conveying drive roller121is rotated in a predetermined direction by the driving force from the drive motor180, with the second folding roller pair nipping the sheet P on which the first crease is formed, to form a second crease on the sheet P. The sheet P on which the second crease is formed is conveyed to the fourth conveyance path404.

Since the first folding roller section130executes the folding process on the sheet P by the rotation of the second conveying drive roller121that functions as the drive roller, the folding process of the sheet P is controlled according to the rotation direction and the rotation speed of the second conveying drive roller121.

The second folding roller section140is disposed downstream from the first folding roller section130in the conveyance direction on the fourth conveyance path404. The second folding roller section140includes an additional-folding drive roller141and an additional-folding driven roller142. The additional-folding drive roller141is rotated by the driving force from the drive motor180in the predetermined direction. The additional-folding driven roller142is rotated according to the rotation of the additional-folding drive roller141in the predetermined direction. The additional-folding drive roller141and the additional-folding driven roller142are rotated with the sheet P on which the crease is formed is nipped in the first folding roller section130, to perform an additional-folding process on the sheet P. The sheet P on which the additional-folding process is performed is conveyed to the discharge roller section150.

The discharge roller section150includes a first discharge roller151, a second discharge roller152, and a third discharge roller153. The first discharge roller151is a drive roller that is rotated by a driving force from the drive motor180. The second discharge roller152and the third discharge roller153are driven rollers that are rotated by the rotation of the first discharge roller151.

When the sheet P that is conveyed by the first conveyor110and the second conveyor120through the second conveyance path402is discharged without a folding process, the sheet P is nipped and discharged by the first discharge roller151and the second discharge roller152. The sheet P that has been additionally folded in the second folding roller section140is nipped between and discharged by the first discharge roller151and the third discharge roller153.

The first sheet detector160is a sensor that detects a leading end of the sheet P conveyed by the first conveyor110and the second conveyor120and is disposed on the second conveyance path402. When the sheet P is folded, the first sheet detector160defines the switching timing at which the rotation direction of the second conveying drive roller121is changed after the sheet P is conveyed in the downstream direction by a predetermined amount from the detection of the leading end of the sheet P with the first sheet detector160. When the first folding roller section130forms a crease on the sheet P, the rotation direction of the second conveying drive roller121is changed at a timing that the sheet P is conveyed by a predetermined amount from the detection of the leading end of the sheet P with the first sheet detector160. As a result, the sheet P is bent between the first conveyor110and the second conveyor120, and the bent portion is guided to the first folding roller section130, thus allowing the first folding roller section130to perform the folding process.

The second sheet detector170is a leading end stopper that detects an end portion of the sheet P on which a crease is formed after passage between the second conveying drive roller121and the first folding roller131. The second sheet detector170is disposed on the third conveyance path403. When the leading end of the sheet P contacts the second sheet detector170and stops, a bend is formed on the sheet P pushed from the upstream in the vicinity of the first folding roller section130. This bend (i.e., a part of the rear end of the sheet P) is nipped between the second conveying drive roller121and the second folding roller132, and the second folding process is performed. The sheet P on which the second folding process is performed is conveyed to the second folding roller section140via the fourth conveyance path404by the driving force of the second conveying drive roller121.

As illustrated inFIGS.23A and23B, the second sheet detector170is not limited to the leading end stopper and may be configured with a sensor and a roller pair whose rotation direction can be controlled, similarly to the first sheet detector160.

An outline of operations performed when the sheet processing unit100performs the folding process is described with reference toFIGS.3to7. As illustrated inFIG.3, the sheet P is conveyed into the sheet processing unit100and is conveyed in the downstream direction by the first conveyor110and the second conveyor120. The rotation direction of the second conveying drive roller121at this time is a counterclockwise (CCW) direction when the second conveying drive roller121is viewed from the positive direction of the X axis with respect to the Y-Z plane inFIG.3. The rotation direction of the second conveying driven roller122driven by the second conveying drive roller121is a clockwise (CW) direction when the second conveying driven roller122is similarly viewed from the positive direction of the X axis with respect to the Y-Z plane.FIGS.4to8are also viewed from the same direction.

Similarly, inFIG.3, the rotation direction of the first conveying drive roller111is the CW direction, and the rotation direction of the first conveying driven roller112is the CCW direction. That is, the sheet P nipped in the first conveyor110is conveyed in the conveyance direction. The leading end of the sheet P nipped by the second conveyor120is also conveyed to the second conveyance path402. Thereafter, the leading end of the sheet P is detected by the sensor of the first sheet detector160. After the sheet P is conveyed by a certain distance from the detection of the leading end, the rotation direction of the second conveying drive roller121is reversed to be the CW direction as illustrated inFIG.4.

Even if the rotation direction of the second conveying drive roller121is switched from the CCW direction to the CW direction, the rotation direction of the first conveying drive roller111is not switched and is maintained to be the CW direction. At this time, a downstream portion of the sheet P in the conveyance direction is conveyed in reverse from the downstream to the upstream. An upstream portion of the sheet P is conveyed from the upstream to the downstream as before. As a result, the sheet P is bent between the second conveyor120and the first conveyor110. If this bent portion is formed toward the first folding roller section130, the state of the sheet P shifts to such a state as illustrated inFIG.5.

As illustrated inFIG.5, the bent portion of the sheet P is nipped between the second conveying drive roller121and the first folding roller131. The bent portion of the sheet P passes through the nip of the second conveying drive roller121and the first folding roller131due to the rotation of the second conveying drive roller121, so that the first crease is formed. At this time, the conveyance direction of the sheet P by the first conveyor110is as before. The upstream portion of the sheet P is conveyed in the direction as before. The downstream portion of the sheet P passes through the first folding roller section130and is conveyed to the third conveyance path403branching from the first conveyance path401.

After that, the end portion (i.e., the portion where the crease is formed) of the sheet P on the third conveyance path403side contacts the leading end stopper as the second sheet detector170(seeFIG.2) and stops. At this time, the upstream portion of the sheet P is continuously conveyed to the third conveyance path403by the first conveyor110, the second conveying drive roller121, and the first folding roller131. As a result, the sheet P is bent in the vicinity of the second conveying drive roller121and the second folding roller132.

As illustrated inFIG.6, the bent portion of the sheet P is nipped between the second conveying drive roller121and the second folding roller132and is conveyed toward the second folding roller section140.

As illustrated inFIG.7, the sheet P on which the crease is formed by the second conveying drive roller121and the second folding roller132is discharged to the fourth conveyance path404.

First Embodiment

Next, a description is given of the sheet processing unit100according to a first embodiment of the present disclosure.FIGS.8to10are explanatory diagrams illustrating a configuration of a drive system of the conveyance roller pairs of the sheet processing unit100. As illustrated inFIG.8, the drive system of the sheet processing unit100mainly includes the drive motor180(serving as the driving force supply source) and a second-conveying-roller-pair drive gear DG20. The second-conveying-roller-pair drive gear DG20is driven by the drive motor180and transmits the driving force. Note that inFIGS.9and10, for convenience of explanation, the first folding roller131and the first conveying driven roller112are omitted.

The second-conveying-roller-pair drive gear DG20is attached to a second conveying roller drive shaft J2as a rotation shaft of the second conveying drive roller121. Accordingly, the rotation direction of the second conveying drive roller121follows the rotation direction of the drive motor180via the second-conveying-roller-pair drive gear DG20.

The drive transmission system of the sheet processing unit100includes a plurality of gears that are combined so as to be rotated by the rotation of the second-conveying-roller-pair drive gear DG20. As illustrated inFIG.8, the drive transmission system includes a first transmission gear AG11and a third transmission gear AG13. The first transmission gear AG11is meshed with the second-conveying-roller-pair drive gear DG20. The third transmission gear AG13is similarly meshed with the second-conveying-roller-pair drive gear DG20. Further, the drive transmission system includes a second transmission gear AG12that is meshed with the first transmission gear AG11. The drive transmission system includes a first-conveying-roller-pair drive first gear DG11and a first-conveying-roller-pair drive second gear DG12. The first-conveying-roller-pair drive first gear DG11is meshed with the second transmission gear AG12. The conveying roller pair drive second gear DG12is meshed with the third transmission gear AG13.

The first-conveying-roller-pair drive first gear DG11and the first-conveying-roller-pair drive second gear DG12are attached to a first conveying roller drive shaft J1that is the rotation shaft of the first conveying drive roller111.

A one-way clutch is built in each of the first-conveying-roller-pair drive first gear DG11and the first-conveying-roller-pair drive second gear DG12. Each of the one-way clutches causes the first-conveying-roller-pair drive first gear DG11or the first-conveying-roller-pair drive second gear DG12to rotate only in the CW direction to transmit the driving force to the first conveying roller drive shaft J1and causes the first-conveying-roller-pair drive first gear DG11or the first-conveying-roller-pair drive second gear DG12so as not to rotate in the CCW direction, thus cutting off the driving force to the first conveying roller drive shaft J1. A description is given of the drive transmission system having the above-described configurations with reference toFIGS.11and12.FIG.11illustrates an example in which the sheet P is conveyed in the conveyance direction and each roller is rotated forward.FIG.12illustrates an example in which the second conveyor120is rotated in reverse so that the sheet P is folded.

As illustrated inFIG.11, when the second-conveying-roller-pair drive gear DG20rotates in the CCW direction due to the rotation of the drive motor180, the first transmission gear AG11rotates in the CW direction and the second transmission gear AG12rotates in the CCW direction. At this time, the second conveyor120rotates forward. The driving force for rotating the first-conveying-roller-pair drive first gear DG11in the CW direction is transmitted from the second transmission gear AG12to the first-conveying-roller-pair drive first gear DG11. Since the one-way clutch built in the first-conveying-roller-pair drive first gear DG11receives the driving force in the CW direction, the driving force for rotating the first conveying roller drive shaft J1in the CW direction is transmitted to the first conveying roller drive shaft J1.

When the second-conveying-roller-pair drive gear DG20rotates in the CCW direction due to the rotation of the drive motor180, the third transmission gear AG13rotates in the CW direction, and the driving force for rotating the first-conveying-roller-pair drive second gear DG12in the CCW direction is transmitted to the first-conveying-roller-pair drive second gear DG12. Since the one-way clutch built in the first-conveying-roller-pair drive second gear DG12cuts off the driving force in the CCW direction, the driving force for rotating the first conveying roller drive shaft J1in the CCW direction is not transmitted to the first conveying roller drive shaft J1.

Accordingly, as illustrated inFIG.11, when the second-conveying-roller-pair drive gear DG20is rotated in the CCW direction by the drive motor180, the driving force transmitted by a first drive transmission path TP1serving as a first drive transmission mechanism rotates the first conveying drive roller111in the CW direction. As a result, as illustrated inFIG.3, the first conveyor110and the second conveyor120convey the sheet P along the conveyance direction.

As illustrated inFIG.12, when the second-conveying-roller-pair drive gear DG20is rotated in the CW direction by the drive motor180, the second conveyor120is rotated in reverse. When the first transmission gear AG11rotates in the CCW direction, the second transmission gear AG12rotates in the CW direction. Thus, the driving force is transmitted to the first-conveying-roller-pair drive first gear DG11to rotate in the CCW direction. However, since the one-way clutch built in the first-conveying-roller-pair drive first gear DG11cuts off the driving force in the CCW direction, the driving force for rotating the first conveying roller drive shaft J1in the CCW direction is not transmitted to the first conveying roller drive shaft J1. Accordingly, since the first conveying roller drive shaft J1does not rotate in the CCW direction, the first conveying drive roller111does not also rotate in the CCW direction. Note that, inFIG.12, for convenience of explanation, the first-conveying-roller-pair drive first gear DG11is omitted.

When the second-conveying-roller-pair drive gear DG20rotates in the CW direction due to the rotation of the drive motor180, the third transmission gear AG13rotates in the CCW direction, and the driving force for rotating the first-conveying-roller-pair drive second gear DG12in the CW direction is transmitted from the third transmission gear AG13to the first-conveying-roller-pair drive second gear DG12. Since the one-way clutch built in the first-conveying-roller-pair drive second gear DG12transmits the driving force in the CW direction, the driving force for rotating the first conveying roller drive shaft J1in the CW direction is transmitted to the first conveying roller drive shaft J1.

Accordingly, as illustrated inFIG.12, when the second-conveying-roller-pair drive gear DG20is rotated in the CW direction by the drive motor180, the driving force transmitted by a second drive transmission path TP2serving as a second drive transmission mechanism rotates the first conveying drive roller111in the CW direction. As illustrated inFIG.4, the first conveyor110conveys the sheet P in the conveyance direction, and the second conveyor120conveys the sheet P in the direction opposite to the conveyance direction (i.e., the upstream side in the conveyance direction).

As described above, the sheet processing unit100according to the present embodiment has a plurality of drive transmission paths (i.e., the first drive transmission path TP1and the second drive transmission path TP2) on which the rotation direction of the first conveying drive roller111is only in the CW direction regardless of whether the rotation direction of the rotation shaft of the drive motor180is the CW direction or the CCW direction.

When the rotation direction of the rotation shaft of the drive motor180is switched, the rotation direction of the second conveying drive roller121is switched. On the other hand, the rotation direction of the first conveying drive roller111may not be switched so that the first conveying drive roller111rotates only in a certain direction. Thus, the operations of the first conveyor110and the second conveyor120are controlled only by the drive force from the drive motor180serving as a single driving force supply source. That is, as described with reference toFIGS.3and4, by switching the rotation direction of the drive motor180at a predetermined timing, the conveyance direction of the downstream portion of the sheet P can be switched to the direction opposite to the conveyance direction (i.e., the upstream side in the conveyance direction). The upstream portion of the sheet P can be conveyed continuously in the conveyance direction. As a result, as illustrated inFIG.4, the sheet P is inserted into the nip between the second conveying drive roller121and the first folding roller131while a bend is formed on the sheet P at a predetermined position, thus allowing a crease to be accurately formed at a predetermined position.

The rotational drive of the first folding roller section130after formation of the bend, and the rotational drive of the second folding roller section140and the discharge roller section150are also performed by the driving force of the drive motor180. Such a configuration can perform the folding process on the sheet P with a reduced size of the sheet processing unit100.

Second Embodiment

Next, a description is given of a sheet processing unit100according to a second embodiment of the present disclosure.FIGS.13to14are diagrams illustrating a configuration of a drive transmission system of conveying roller pairs in the sheet processing unit100according to the second embodiment. As illustrated inFIGS.13and14, the drive system of the sheet processing unit100mainly includes the drive motor180(serving as the driving force supply source) and a second-conveying-roller-pair drive gear DG200. The second-conveying-roller-pair drive gear DG200is driven by the drive motor180and transmits the driving force.

The second-conveying-roller-pair drive gear DG200is attached to the second conveying roller drive shaft J2as the rotation shaft of the second conveying drive roller121. Accordingly, the rotation direction of the second conveying drive roller121is the same as the rotation direction of the second-conveying-roller-pair drive gear DG200and follows the rotation direction of the drive motor180. When the drive motor180is rotated forward, the second conveying drive roller121and the second-conveying-roller-pair drive gear DG200are also rotated forward. When the drive motor180is rotated in reverse, the second conveying drive roller121and the second-conveying-roller-pair drive gear DG200are also rotated in reverse.

A drive transmission idler gear pulley GP103meshes with the second-conveying-roller-pair drive gear DG200. The drive transmission idler gear pulley GP103rotates as the driving force is transmitted to the drive transmission idler gear pulley GP103by the rotation of the second-conveying-roller-pair drive gear DG200.

As illustrated inFIG.14, the drive transmission idler gear pulley GP103is roughly classified into a large-diameter portion and a small-diameter portion. The large-diameter portion meshes with the second-conveying-roller-pair drive gear DG200and a first-conveying-roller-pair drive gear DG101. A first timing belt104is wound around the small-diameter portion.

The first timing belt104is also wound around a first-conveying-roller-pair drive pulley105serving as a transmission mechanism of the first conveying roller drive shaft J1that is the drive shaft of the first conveying drive roller111. Accordingly, when the drive transmission idler gear pulley GP103rotates, the driving force thereof also rotate the first-conveying-roller-pair drive pulley105via the first timing belt104.

The first-conveying-roller-pair drive pulley105is attached to the first conveying roller drive shaft J1serving as the rotation shaft of the first conveying drive roller111. The first-conveying-roller-pair drive gear DG101is also attached to the first conveying roller drive shaft J1. The first-conveying-roller-pair drive gear DG101also meshes with the large-diameter portion of the second-conveying-roller-pair drive gear DG200.

Accordingly, in the sheet processing unit100according to the present embodiment, the driving force supplied from the drive motor180drives the second conveying drive roller121and also drives the first conveying drive roller111by transmitting the driving force to the first conveying drive roller111.

The driving force transmission path to the first conveying drive roller111has a configuration in which two paths coexist. In the first path serving as the first drive transmission mechanism, as illustrated inFIG.15, the driving force transmitted from the second-conveying-roller-pair drive gear DG200via the large diameter portion of the drive transmission idler gear pulley GP103is transmitted to the small diameter portion of the drive transmission idler gear pulley GP103, the first timing belt104, and the first-conveying-roller-pair drive pulley105. In the second path serving as the second drive transmission mechanism, as illustrated inFIG.16, the driving force transmitted from the second-conveying-roller-pair drive gear DG200via the large diameter portion of the drive transmission idler gear pulley GP103is transmitted via the first-conveying-roller-pair drive gear DG101.

A one-way clutch is built in each of the first-conveying-roller-pair drive gear DG101and the first-conveying-roller-pair drive pulley105. The one-way clutch transmits the driving force in only one direction and cut offs the driving force in the other direction so that corresponding one of the first-conveying-roller-pair drive gear DG101and the first-conveying-roller-pair drive pulley105rotates forward (i.e., the rotation in the CW direction illustrated inFIGS.15and16) but does not rotate in reverse.

A description is given of the driving system having the above-described configurations with reference toFIGS.15and16. As illustrated inFIG.15, when the second-conveying-roller-pair drive gear DG200rotates in the CCW direction due to the rotation of the drive motor180, the drive transmission idler gear pulley GP103rotates in the CW direction. A driving force in the CCW direction is transmitted to the first-conveying-roller-pair drive gear DG101that meshes with the large diameter portion of the drive transmission idler gear pulley GP103. However, the built-in one-way clutch cuts off the driving force.

At this time, the small diameter portion of the drive transmission idler gear pulley GP103rotates in the CW direction, and the rotation is transmitted to the first-conveying-roller-pair drive pulley105via the first timing belt104. The first-conveying-roller-pair drive pulley105rotates in the CW direction, which is the same direction as the rotation direction of the drive transmission idler gear pulley GP103. The one-way clutch built in the first-conveying-roller-pair drive pulley105transmits the driving force for rotating the first-conveying-roller-pair drive pulley105in the CW direction. Accordingly, when the first-conveying-roller-pair drive pulley105rotates in the CW direction, the first conveying roller drive shaft J1also rotates in the CW direction, and first conveying drive roller111rotates in the CW direction.

That is, in the second embodiment, the path through which the driving force is transmitted from the second-conveying-roller-pair drive gear DG200to the first-conveying-roller-pair drive pulley105via the small diameter portion of the drive transmission idler gear pulley GP103corresponds the first drive transmission path TP1illustrated inFIG.11.

As illustrated inFIG.16, when the second-conveying-roller-pair drive gear DG200rotates in the CW direction due to the rotation of the drive motor180, the drive transmission idler gear pulley GP103rotates in the CCW direction. The first-conveying-roller-pair drive gear DG101that meshes with the large diameter portion of the drive transmission idler gear pulley GP103rotates in the CW direction. Since the first-conveying-roller-pair drive gear DG101has a built-in one-way clutch so as to rotate in the CW direction, the driving force for rotating the first conveying roller drive shaft J1in the CW direction is transmitted to the first conveying roller drive shaft J1, and the first conveying roller pair rotates forward.

At this time, the rotation of the small diameter portion of the drive transmission idler gear pulley GP103is also transmitted to the first-conveying-roller-pair drive pulley105via the first timing belt104. The first-conveying-roller-pair drive pulley105rotates in the same direction (i.e., CCW direction) as the rotation direction of the drive transmission idler gear pulley GP103. In this case, the driving force for rotating the first-conveying-roller-pair drive pulley105in the CCW direction is transmitted to the first-conveying-roller-pair drive pulley105. However, this driving force is cut off by the one-way clutch. As a result, the rotation of the first-conveying-roller-pair drive pulley105is not transmitted to the first conveying drive roller111.

When the second conveying drive roller121rotates in the CW direction due to the rotation of the drive motor180, the driving force for rotating the first-conveying-roller-pair drive gear DG101in the CW direction is transmitted from the second-conveying-roller-pair drive gear DG200to the first-conveying-roller-pair drive gear DG101via the large diameter portion of the drive transmission idler gear pulley GP103. Accordingly, the first conveying roller drive shaft J1rotates in the CW direction.

That is, in the second embodiment, the path through which the driving force is transmitted from the second-conveying-roller-pair drive gear DG200to the first-conveying-roller-pair drive gear DG101via the large diameter portion of the drive transmission idler gear pulley GP103corresponds the second drive transmission path TP2illustrated inFIG.12.

As described above, when the rotation direction of the rotation shaft of the drive motor180is switched, the rotation direction of the second conveying drive roller121is switched. On the other hand, the rotation direction of the first conveying drive roller111is not switched and the first conveying drive roller111rotates only in a certain direction. Such a configuration, as described above, allows a plurality of conveying roller pairs to perform the folding process by the driving force of the drive motor180serving as the single driving force supply source at a predetermined timing. When the rotation direction of the drive motor180is switched. an upstream portion of the sheet P can be maintained as being conveyed in the conveyance direction while the direction of a downstream portion of the sheet P is switched to the upstream direction. As a result, as illustrated inFIG.4, the sheet P is inserted into the nip between the second conveying drive roller121and the first folding roller131while a bend is formed on the sheet P at a predetermined position, thus allowing a crease to be accurately formed at a predetermined position.

After the bend is formed, the rotational drive of the first folding roller section130and the rotational drive of the second folding roller section140and the discharge roller section150are also performed by the driving force of the drive motor180. Such a configuration can perform the folding process on the sheet P with a reduced size of the sheet processing unit100.

Referring toFIGS.17A to23B, a description is given of the flow of a folding operation that can be performed in the configuration of the sheet processing unit100according to the second embodiment. The sheet processing unit100according to the present embodiment is disposed on the backward of the conveyance path of the sheet P. To facilitate the explanation, a state in which the configuration illustrated inFIG.13is viewed from the opposite side is illustrated in each ofFIGS.17A to23B. Accordingly, the rotation direction (CW or CCW direction) used in the description ofFIGS.17A to23Bis opposite to the rotation direction (CW or CCW direction) illustrated inFIGS.15and16.

InFIGS.17A to23B,FIGS.17A,18A,19A,20A,21A,22A, and23Aillustrate the arrangement of the drive system that transmits the driving force to the conveying roller pairs to rotate in predetermined directions, and the rotation direction of the configuration of each drive system.FIGS.17B,18B,19B,20B,21B,22B, and23Billustrate the arrangement and the rotation directions of the conveying roller pairs.

When the second-conveying-roller-pair drive gear DG200rotates in the CW direction inFIG.17A, the second conveyor120including the second conveying drive roller121and the second conveying driven roller122rotates forward. When the second-conveying-roller-pair drive gear DG200rotates in the CW direction, the first-conveying-roller-pair drive gear DG101also rotates in the CW direction. As illustrated inFIG.15, the drive transmission to the first conveying drive roller111is cut off by the action of the one-way clutch built in the first-conveying-roller-pair drive gear DG101.

On the other hand, when the second-conveying-roller-pair drive gear DG200rotates in the CW direction, the drive transmission idler gear pulley GP103rotates in the CCW direction. The rotation of the drive transmission idler gear pulley GP103is transmitted to the first-conveying-roller-pair drive pulley105via the first timing belt104that meshes the small diameter portion of the drive transmission idler gear pulley GP103. The first-conveying-roller-pair drive pulley105rotates in the CCW direction, and the driving force in the CCW direction is transmitted to the first conveying drive roller111.

As a result, the driving force is transmitted to the first conveying drive roller111, and the first conveyor110including the first conveying drive roller111and the first conveying driven roller112also rotates forward. Note that “rotate forward” means the rotation direction of each roller that constitutes the first conveyor110and the second conveyor120when the sheet P is conveyed in the conveyance direction illustrated inFIGS.17A and17B.

A second-conveying-driven-roller first gear SG201, a second-conveying-driven-roller second gear SG202, and a drive transmission idler gear G81mesh with the small diameter portion (seeFIG.14) of the second-conveying-roller-pair drive gear DG200. The second-conveying-driven-roller first gear SG201, the second-conveying-driven-roller second gear SG202, and the drive transmission idler gear G81rotate in the direction opposite to the rotation direction of the second-conveying-roller-pair drive gear DG200. Accordingly, as illustrated inFIG.17A, when the rotation direction of the second-conveying-roller-pair drive gear DG200is in the CW direction, the second-conveying-driven-roller first gear SG201, the second-conveying-driven-roller second gear SG202, and the drive transmission idler gear G81rotate in the CCW direction.

The second-conveying-driven-roller first gear SG201rotates the first folding roller131. The second-conveying-driven-roller second gear SG202rotates the second folding roller132. Accordingly, when the second-conveying-driven-roller first gear SG201and the second-conveying-driven-roller second gear SG202rotate in the CCW direction, the first folding roller131and the second folding roller132also rotate in the CCW direction.

An additional-folding drive gear G61also meshes with the drive transmission idler gear G81. An additional-folding drive gear G62meshes with the additional-folding drive gear G61. A second timing belt601is wound around the rotation shaft of the additional-folding drive gear G61. The second timing belt601is also wound around the rotation shaft of a discharge drive gear G71. With such a configuration, when the drive transmission idler gear G81rotates, the driving force is transmitted to the additional-folding drive gear G61, the additional-folding driven gear G62, and the discharge drive gear G71, thus rotating each of the gears.

The additional-folding drive roller141is disposed on the rotation shaft of the additional-folding drive gear G61. The additional-folding driven roller142is disposed on the rotation shaft of the additional-folding driven gear G62. The first discharge roller151is disposed on the rotation shaft of the discharge drive gear G71.

Accordingly, when the second-conveying-roller-pair drive gear DG200rotates in the CW direction, the drive transmission idler gear G81rotates in the CCW direction, and the additional-folding drive gear G61and the discharge drive gear G71rotate in the CW direction. Then, the additional-folding driven gear G62rotates in the CCW direction, and the discharge drive gear G71rotates in the CW direction. As a result, the additional-folding drive roller141rotates in the CW direction, the additional-folding driven roller142rotates in the CCW direction, and the first discharge roller151rotates in the CW direction.

Subsequently, as illustrated inFIG.18B, when the sheet P is carried in, the first conveying drive roller111and the first conveying driven roller112rotate forward by the driving force of the drive motor180(seeFIG.15). The second conveying drive roller121and the second conveying driven roller122also rotate forward. Accordingly, the sheet P is conveyed in the conveyance direction. After the leading end of the sheet P is detected by the first sheet detector160, the sheet P is continuously conveyed to a designated length L, and the drive motor180is rotated in the reverse direction.

When the rotation direction of the drive motor180is switched, as illustrated inFIG.19A, the second-conveying-roller-pair drive gear DG200rotates in the CCW direction inFIG.19A, and the rotation direction of the second conveyor120that includes the second conveying drive roller121and the second conveying driven roller122is reversed. On the other hand, when the second-conveying-roller-pair drive gear DG200rotates in the CCW direction, the first-conveying-roller-pair drive gear DG101also rotates in the CCW direction, so that the driving force in the CCW direction is transmitted to the first conveying drive roller111. At this time, the first-conveying-roller-pair drive pulley105rotates in the CW direction via the first timing belt104hung on the small diameter portion of the drive transmission idler gear pulley GP103. The drive transmission to the first conveying drive roller111is cut off by the action of the one-way clutch built in the first-conveying-roller-pair drive pulley105as illustrated inFIG.16.

With such a configuration, the first conveyor110including the first conveying drive roller111and the first conveying driven roller112also rotate forward. That is, while the conveyance direction of the downstream portion of the sheet P is switched to the direction opposite to the conveyance direction (i.e., the upstream side in the conveyance direction), the upstream portion of the sheet P can be conveyed continuously in the conveyance direction.

As a result, as illustrated inFIG.4, the sheet P is inserted into the nip between the second conveying drive roller121and the first folding roller131while a bend is formed on the sheet P in the vicinity of the nip between the second conveying drive roller121and the first folding roller131in the first conveyance path401, thus allowing a crease to be accurately formed at a predetermined position.

The bend of the sheet P is nipped between the second conveying drive roller121and the first folding roller131each rotating in the direction to convey the sheet P toward the third conveyance path403, and the first folding process is performed. Thereafter, when the sheet P continues to be conveyed toward the third conveyance path403as it is, as illustrated inFIG.20B, the first crease moves to a position where the first crease contacts the second sheet detector170serving as the leading end stopper.

As illustrated inFIG.20B, the leading end stopper includes a wall portion that contacts the sheet P and a shaft that fixes and holds the wall portion. The wall portion is rotatable with the shaft as the rotation center. By rotating the wall portion around the shaft to a predetermined position and then fixing the wall portion, the position of the second crease formed on the sheet P can be adjusted according to the type of folding. A leading end of the sheet P contacts the wall portion whose position has been adjusted, and a trailing end of the sheet P is continuously conveyed by the first conveyor110, the second conveying drive roller121, and the first folding roller131. Thus, a bend for folding the second crease on the sheet P is formed in the vicinity of the nip between the second conveying drive roller121and the second folding roller132in the third conveyance path403.

The bend for forming the second crease formed on the sheet P is inserted into the nip between the second conveying drive roller121and the second folding roller132. Thus, the sheet P is conveyed to the fourth conveyance path404in a state in which the second crease is formed on the sheet P as illustrated inFIG.21B.

Thereafter, the sheet P on which the second crease is formed is discharged by the first discharge roller151and the second discharge roller152constituting the discharge roller section150as illustrated inFIG.22B.

In some embodiments, as illustrated inFIG.23B, the second sheet detector170may be replaced with a combination of a third conveying roller pair171and a second forward-reverse rotation sensor172. In this case, the third conveying roller pair171is rotated in reverse to convey the sheet P on which the first crease is formed in the direction opposite to the conveyance direction. When a predetermined time has elapsed since the leading end of the sheet P on which the first crease is formed is detected, the reverse rotation of the third conveying roller pair171is stopped. Thereafter, as illustrated inFIG.23B, the third conveying roller pair171is rotated forward to form the second crease on the sheet P in the vicinity of the nip between the second conveying drive roller121and the second folding roller132.

FIG.24is a block diagram illustrating a control configuration of the image forming system1000according to the present embodiment of this disclosure. As illustrated inFIG.24, the sheet processing unit100includes a central processing unit (CPU)100aand a control circuit including a microcomputer having an input-output (I/O) interface100b. The CPU100areceives signals from the CPU100aof the image forming unit200, each switch of the operation panel301, and the sheet detection sensors including the first sheet detector160and the second sheet detector170, via a communication interface100c. The CPU100aperforms a predetermined control based on a signal input from the image forming unit200. The CPU100acontrols solenoids and motors including the drive motor180, via drivers and motor drivers for controlling the rotation direction and the rotation speed of the drive motor180, and acquires the data of the sheet sensors in the printer1via the communication interface100c. Further, for example, the CPU100acontrols the drive control of the drive motor180by the motor driver via the I/O interface100bwith respect to the control object, and acquires the data from each sheet sensor. Note that the operation of the sheet processing unit100and the operation of the whole printer1are controlled by the CPU100areading program code stored in a read only memory (ROM)1001and expanding the program code into a random access memory (RAM)1002, and using the RAM1002as a work area and a data buffer, and are performed based on the program defined in the program code.

In the present embodiment, the folding operation that can be performed by the folding mechanism illustrated inFIG.2is instructed and executed by the CPU100aillustrated inFIG.24.

As described above, the drive transmission system of the sheet processing unit100according to the present embodiment includes a plurality of transmission paths of the first drive transmission path TP1and the second drive transmission path TP2. The driving force transmitted in the first drive transmission path TP1and the second drive transmission path TP2is supplied from the drive motor180. The first drive transmission path TP1is a transmission path that rotates the second conveyor120forward and rotates the first conveyor110forward. The second drive transmission path TP2is a transmission path that rotates the second conveyor120in reverse and rotates the first conveyor110forward.

The reduction ratios of the drive systems in the two drive transmission paths TP1and TP2are adjusted and set, so that the conveying speed of the sheet P by the first conveyor110serving as the first conveying roller pair and the conveying speed of the sheet P by the second conveyor120serving as the second conveying roller pair can be adjusted.

For example, as illustrated inFIG.25A, when the first conveyor110and the second conveyor120are rotated forward, a second conveyance speed V2of the sheet P by the second conveyor120is not higher than a first conveyance speed V1of the sheet P by the first conveyor110. When the second conveyor120is reversed while the first conveyor110rotates forward, a fourth conveyance speed V4of the sheet P by the second conveyor120is not higher than a third conveyance speed V3of the sheet P by the first conveyor110.

By adjusting as described above, the folding process can be performed without causing the sheet P to be pulled between the first conveyor110and the second conveyor120at any of the conveyance timings. The amount of bend of the sheet P between the first conveyor110and the second conveyor120can be controlled to a certain amount. As a result, the first crease can be accurately formed at a predetermined position on the sheet P.

In the second embodiment, for example, it is assumed that in the drive transmission path for transmitting the driving force to the first-conveying-roller-pair drive gear DG101, the total reduction ratio from the drive motor180to the second-conveying-roller-pair drive gear DG200is 5.56. In this case, the total reduction ratio of the path for transmitting the driving force from the drive motor180to the first-conveying-roller-pair drive gear DG101via the drive transmission idler gear pulley GP103is set to 5.5. Accordingly, the first conveyance speed V1can be set to be 1% faster than the second conveyance speed V2. The third conveyance speed V3is also 1% faster than the fourth conveyance speed V4.

When the size of the sheet P to be folded is A4 size which is one of the specified sizes and the sheet P is folded in three-ply, the conveyance amount is about 90 to 180 mm. The bend generated during conveyance is 0.9 to 1.8 mm Assuming that the dimensional tolerance of the roller diameter of each roller constituting the first conveyor110and the second conveyor120is ±0.1 mm, even if the roller pair of the first conveyor110has a negative tolerance and the roller pair of the second conveyor120has a positive tolerance, the relation of V1≥V2is always satisfied. Accordingly, the sheet P is not pulled between the first conveyor110and the second conveyor120.

As described above, the reduction ratio may be set in consideration of the specifications (e.g., compatible sizes) of the sheet processing unit100and the dimensional tolerance of each component so that the amount of bend of the sheet P formed between the first conveyor110and the second conveyor120does not exceed a certain amount during the conveyance of the sheet P.

Next, the operation control flows in the sheet processing unit100according to the first embodiment and the second embodiment are described with reference to the flowchart inFIGS.26and27. The flowchart described below corresponds to the processing of the control program executed by the CPU100a.

The sheet processing unit100receives the sheet P from the image forming unit200(S2601). Subsequently, the first conveyor110serving as the first conveying roller pair and the second conveyor120serving as the second conveying roller pair are rotated forward (S2602). Accordingly, the sheet P is conveyed from the first conveyance path401to the second conveyance path402.

Along with the conveyance of the sheet P, a determination process of whether the sheet sensor of the first sheet detector160detects the sheet P is performed (S2603). The conveyance of the sheet P continues until the sheet P is detected by the sheet sensor (S2603: NO). When the sheet sensor of the first sheet detector160detects the sheet P (S2603: YES), it is determined whether the sheet P has been conveyed by the designated length L (S2604).

The conveyance of the sheet P continues from the time when the sheet P is detected by the sheet sensor until the sheet P has been conveyed by the designated length L (S2604: NO). When the sheet P has been conveyed by the designated length L (S2604: YES), the second conveyor120is reversed. A bent portion of the sheet P is conveyed from the first conveyance path401to the third conveyance path403so that the sheet P is fold (S2605).

As illustrated inFIGS.23A and23B, when the second sheet detector170includes the third conveying roller pair171and the second forward-reverse rotation sensor172, the operation control flow is as illustrated in the flowchart inFIG.27.

In this case, the process from receiving the sheet P from the image forming unit200to determining whether the sheet P has been conveyed by the designated length L and the subsequent process until the second conveyor120reversely conveys the sheet P are the same as the processes of S2601to S2605(S2701to S2705).

Subsequently, a determination process is performed to determine whether the sheet P conveyed along the third conveyance path403is detected by the second forward-reverse rotation sensor172(S2706). The sheet P is conveyed in the third conveyance path403until the sheet P is detected by the second forward-reverse rotation sensor172(S2706: NO). When the second forward-reverse rotation sensor172detects the sheet P (S2706: YES), it is determined whether it is the timing of reversing the conveyance of the sheet P (S2707).

When it is the timing of reversing the conveyance of the sheet P (S2707: YES), the conveyance direction is switched again so that the sheet P is conveyed from the third conveyance path403to the fourth conveyance path404(S2708).

As described above, the sheet processing unit100according to the present embodiment exhibits an effect that both downsizing and cost reduction can be realized at the same time.

In the sheet processing unit100according to the present embodiment, a predetermined driving force is transmitted to the first conveying roller pair and the second conveying roller pair by the drive motor180(serving as the single driving force supply source) and a plurality of drive transmission paths. Thus, the device for folding the sheet P can be miniaturized.

In the sheet processing unit100according to the present embodiment, the first conveying roller pair is driven by receiving only the driving force from one side and the driving force in the opposite direction transmitted from each drive transmission path is cut off. Thus, the first conveying roller pair can be driven to rotate in the first direction (i.e., rotate forward) at any time.

In the sheet processing unit100according to the present embodiment, even though the rotation of each roller pair is controlled by the driving force supplied from the drive motor180serving as the single driving force supply source, the conveyance speed of an upstream portion of a sheet P is adjusted to be faster, thus preventing the sheet P from being pulled in opposite directions during conveyance.

In the sheet processing unit100according to the present embodiment, even if the rotation of each roller pair is controlled by the driving force supplied from the drive motor180serving as the driving force supply source, the conveyance speed of an upstream portion of the sheet P is adjusted to be faster, thus preventing the sheet P from being pulling from both sides during folding process.

In the sheet processing unit100according to the present embodiment, only the driving force in a certain direction can be transmitted by using the one-way clutch, thus allowing the conveying roller pair to appropriately receive the driving force from the two drive transmission mechanisms. This configuration can be achieved with a simple configuration that does not use an electromagnetic clutch or the like.

In the sheet processing unit100according to the present embodiment, a simple configuration and an arbitrary reduction ratio can be set depending on the number of teeth of the gears and the timing belt, and the conveyance speed of the sheet by the first conveying roller pair and the second conveying roller pair can be preferably set. Such a configuration can prevent the sheet P from being pulled in opposite directions by a plurality of conveying roller pairs both when the sheet P is conveyed and when the sheet P is folded.

Note that embodiments of the present disclosure are not limited to the specific embodiments described above, and numerous additional modifications and variations are possible in light of the teachings within the technical scope of the appended claims. It is therefore to be understood that the disclosure of this patent specification may be practiced otherwise by those skilled in the art than as specifically described herein, and such variations, modifications, alternatives are within the technical scope of the appended claims.

This patent application is based on and claims priority to Japanese Patent Application Nos. 2021-022618, filed on Feb. 16, 2021, and 2021-197026, filed on Dec. 3, 2021, in the Japan Patent Office, the entire disclosure of each of which is hereby incorporated by reference herein.

REFERENCE SIGNS LIST

1Printer100Sheet processing unit104First timing belt105First conveying roller pair drive pulley110First conveyor111First conveying drive roller112First conveying driven roller120Second conveyor121Second conveying drive roller122Second conveying driven roller130First folding roller section131First folding roller132Second folding roller140Second folding roller section141Additional folding drive roller142Additional folding driven roller150Discharge roller section151First discharge roller152Second discharge roller153Third discharge roller160First sheet detector170Second sheet detector171Third conveying roller pair172Second forward-reverse sensor180Drive motor200Image forming unit301Operation panel401First conveyance path402Second conveyance path403Third conveyance path404Fourth conveyance path601Second timing beltAG11First transmission gearAG12Second transmission gearAG13Third transmission gearDG101First conveying roller pair drive gearDG11First conveying roller pair drive first gearDG12First conveying roller pair drive second gearDG20Second conveying roller pair drive gearDG200Second conveying roller pair drive gearG61Additional folding drive gearG62Additional folding driven gearG71Discharge drive gearG81Drive transmission idler gearGP103Drive transmission idler gear pulleyJ1First conveying roller drive shaftJ2Second conveying roller drive shaftSG201Second conveying driven roller first gearSG202Second conveying driven roller second gearTP1First drive transmission pathTP2Second drive transmission path