Patent ID: 12221311

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Some aspects of the present disclosure will be described briefly below. According to a first aspect of the present disclosure, a medium stacking apparatus includes: a placement section having a placement area in which one or more media that recorded medium are placed; an alignment section that aligns downstream, leading edges, in a transport direction, of the media that were transported to the placement section; a transport section that transports, to the alignment section, the media that were transported to the placement section; and a moving section that moves the media stacked on the placement section in a width direction, the width direction intersecting the transport direction. The alignment section includes: a first alignment surface having a first friction coefficient for contact with the media; and a second alignment surface having a second friction coefficient for contact with the media, the second friction coefficient being lower than the first friction coefficient. The second alignment surface is positioned upstream of the first alignment surface in the transport direction and closer to a center of the placement area in the width direction than the first alignment surface is.

Suppose an uppermost one of a plurality of media stacked on the placement section is transported over the other media, and this uppermost medium is warped. When transported to the alignment section by the transport section, the uppermost medium may be angled with respect to a straight line extending in the transport direction or the width direction. Following this, a portion of the downstream, leading edge of the angled uppermost medium in the transport direction might come into contact with the first alignment surface and then unexpectedly move toward the placement section. With the first aspect, however, the first alignment surface, the first friction coefficient of which is higher than the second friction coefficient of the second alignment surface, applies a relatively large friction force to the portion of the leading edge in the direction opposite to the moving direction. Therefore, this configuration can suppress this portion from entering into the space between the alignment section and the downstream, leading edges of the media that have already been stacked.

When the uppermost medium is further transported, the portion of the leading edge of the medium is curled, and another portion of the leading edge reaches substantially the same location as this curled portion in the transport direction. Then, the pressing force that the transport section has applied to the uppermost medium is released, so that the angle of the uppermost medium is corrected. In this case, the other portion of the leading edge is in contact with the second alignment surface. Since the second alignment surface is positioned upstream of the first alignment surface in the transport direction, the leading edge of the uppermost medium comes off the first alignment surface and, in turn, comes into contact with the second alignment surface during the correction of the angle of the uppermost medium. As a result, portions of the leading edges of the plurality of media, including the uppermost medium, stacked on the placement section come into contact with the second alignment surface.

When the moving section moves the plurality of media including the uppermost medium in the width direction, the second alignment surface, the second friction coefficient of which is lower than the first friction coefficient of the first friction member, applies a relatively small friction force to the leading edges of the paper sheets in the direction opposite to the moving direction. Thus, the moving section can move the media in the width direction with only a light load placed on the media. With the first aspect, the medium stacking apparatus can be formed with a simple configuration because it is unnecessary to move the first alignment surface or the second alignment surface.

According to a second aspect of the present disclosure, the medium stacking apparatus of the first aspect may have a configuration in which the alignment section further includes a third alignment surface positioned closer to the center in the width direction than the second alignment surface is. In addition, the third alignment surface may have a third friction coefficient for contact with the media, the third friction coefficient being higher than the second friction coefficient. The third alignment surface may be positioned downstream of the second alignment surface in the transport direction.

In the second aspect, when the medium is further transferred in the transport direction after the leading edge of the medium has come into the second alignment surface, the center of the medium in the width direction comes into contact with the third alignment surface. In this case, even if the leading edge of the medium moves toward the placement section, the third alignment surface, the third friction coefficient of which is higher than the second friction coefficient of the second alignment surface, applies a relatively large friction force to the center, in the width direction, of the medium in the direction opposite to the moving direction. Therefore, this configuration can suppress the leading edge of the medium in the transport direction from entering into the space between the third alignment surface and the leading edges of the media that have already been stacked. Moreover, since the third alignment surface is disposed downstream of the second alignment surface in the transport direction, the media come into contact with the third alignment surface less frequently than the second alignment surface. Therefore, the moving section can move the plurality of media in the width direction under only a light load.

According to a third aspect of the present disclosure, the medium stacking apparatus of the second aspect may have a configuration in which the first alignment surface is positioned upstream of the third alignment surface in the transport direction.

When the medium is angled with respect to a straight line extending in the transport direction, one corner of the leading edge of the medium is transported ahead of the other corner and is positioned downstream of the center of the leading edge of the medium in the transport direction. In other words, the downstream corner of the leading edge of the angled medium is positioned ahead of the center thereof in the transport direction. With the third aspect, the first alignment surface is positioned upstream of the third alignment surface in the transport direction. The downstream corner of the leading edge of the medium thus comes into contact with the first alignment surface having a relatively high friction coefficient earlier than when the center thereof comes into contact with the third alignment surface having a relatively low friction coefficient. This configuration can suppress the medium from entering into the space between the first alignment surface and the leading edges, in the transport direction, of the media that have already been stacked. Moreover, when the moving section moves the plurality of media in the width direction after the angle of the medium has been corrected by bringing the leading edge into contact with the first alignment surface, these media come into contact with the second alignment surface having a relatively low friction coefficient. Therefore, the moving section can move the media in the width direction under only a light load.

According to a fourth aspect, the medium stacking apparatus of the second aspect may have a configuration in which the third alignment surface is positioned upstream of the first alignment surface in the transport direction.

When the medium being transferred toward the alignment section is not angled or is slightly angled, the center of the leading edge of the medium in the width direction may be positioned downstream of the corner thereof in the transport direction after the leading edge of the medium has come into contact into the second alignment surface. With the fourth aspect, the third alignment surface is positioned upstream of the first alignment surface in the transport direction. The center of the leading edge of the medium being transported ahead of the corner thereof thus comes into contact with the third alignment surface having a relatively high friction coefficient earlier than the corner does. This configuration can suppress the medium from entering into the space between the third alignment surface and the leading edges, in the transport direction, of the media that have already been stacked. Moreover, when the moving section moves the plurality of media in the width direction after the angle of the medium has been corrected by bringing the leading edge of the medium into contact with the third alignment surface, these media come into contact with the second alignment surface having a relatively low friction coefficient. As a result, the moving section can move the media under only a light load.

According to the fifth aspect, the medium stacking apparatus of one of the first to fourth aspects may have a configuration in which the alignment section includes a plurality of first alignment surfaces and a plurality of second alignment surfaces. Further, the plurality of first alignment surfaces may be arranged on both sides of the placement area with respect to the center in the width direction; the plurality of second alignment surfaces may be arranged on both sides of the placement area with respect to the center in the width direction.

Even when the medium being transferred to the alignment section is angled, the leading edge of the medium can reliably come into contact with the first alignment surface and the second alignment surface in this order, independently of its angled orientation, more specifically regardless of which corner, in the width direction, of the leading edge of the medium is positioned ahead.

According to a sixth aspect, the medium stacking apparatus of one of the first to fifth aspects may have a configuration in which the first friction coefficient of the first alignment surface is higher than the second friction coefficient of the second alignment surface at least in a stacking direction of the media.

With the sixth aspect, since the first friction coefficient of the first alignment surface is higher than the second friction coefficient of the second alignment surface at least in the stacking direction, it is possible to suppress the downstream, leading edge of the medium from entering into the space between the alignment section and the downstream, leading edges of the media that have already been stacked on the placement section. Therefore, the medium being transported to the placement section does not affect the alignment of the leading edges of the media that have already been stacked.

According to a seventh aspect, the medium stacking apparatus of one of the first to sixth aspects may have a configuration in which the alignment section further includes a first friction member provided with the first alignment surface and a mounting member to which the first friction member is attached.

With the seventh aspect, the first friction member provided with the first alignment surface is replaceable. Thus, when the first alignment surface is worn out, it is only necessary to replace the first friction member provided with this first alignment surface without replacing the entire alignment section. It is consequently possible to avoid discarding many components in the process of replacing the first alignment surface.

According to an eighth aspect, the medium stacking apparatus of the seventh aspect may have a configuration in which the second alignment surface is formed on a second friction member, the second friction member being attached to at least one of the mounting member and the first friction member.

With the eighth aspect, the second friction member provided with the second alignment surface is replaceable. Thus, when the second alignment surface is worn out, it is only necessary to replace the second friction member provided with this second alignment surface without replacing the entire alignment section. It is consequently possible to avoid discarding many components in the process of replacing the second alignment surface.

According to a ninth aspect, the medium stacking apparatus of the seventh aspect may have a configuration in which the second alignment surface is formed on the mounting member.

With the ninth aspect, the medium stacking apparatus can be fabricated without performing a process of attaching a member provided with the second alignment surface to the mounting member.

According to a tenth aspect, a postprocessing apparatus includes: the medium stacking apparatus according to one of the first to ninth aspects; and a processing section that processes the plurality of media stacked on the placement section.

With the tenth aspect, the moving section can move the plurality of media in the width direction with only a light load placed on the media, thereby reducing the risk of the media being distorted.

First Embodiment

A description will be given below in detail of a record system1, a postprocessing apparatus30, and a stacking unit34according to a first embodiment, which is an example of the present disclosure. As illustrated inFIG.1, the record system1includes a printer10, a scanner unit12, and the postprocessing apparatus30, for example. The record system1may be an ink jet recording system that discharges an ink Q onto a paper sheet P, thereby recording desired information thereon. In this case, the ink Q is an example of a liquid; the paper sheet P is an example of a medium.

Some accompanying drawings employ an X-Y-Z coordinate system. The ±X directions are examples of a depth direction of the record system1: the +X direction corresponds to the X-arrow direction, and the −X direction corresponds to the direction opposite to the X-arrow direction. Also, the ±X directions are examples of a width direction of the paper sheet P. The ±Y directions are examples of a width direction of the record system1: the +Y direction corresponds to the Y-arrow direction, and the −Y direction corresponds to the direction opposite to the Y-arrow direction. The +Z directions, which are orthogonal to the ±X and ±Y directions, are examples of a height direction of the record system1: the +Z direction corresponds to the Z-arrow direction, and the −Z direction corresponds to the direction opposite to the Z-arrow direction. Hereinafter, the +Z direction is also referred to as the upper direction; the −Z direction is also referred to as the lower direction.

The printer10is an example of a recoding apparatus that records information on a paper sheet P. The printer10includes: for example, a main body14; a sheet storage section16that accommodates paper sheets P; a paper sheet transport section (not illustrated) that transports the paper sheets P; a recording section18that records information on the paper sheets P; an inside discharge section22that ejects the paper sheets P; a relay unit24via which the paper sheets P are to be transported to the postprocessing apparatus30; and a controller (not illustrated). In the main body14, a transport route TA along which the paper sheets P are to be transported is formed.

The recording section18, which may be formed as a line head, has a plurality of nozzles (not illustrated) arranged so as to cover the entire surface area of a paper sheet P in the +X direction. The recording section18is supplied with the ink Q from an ink tank (not illustrated) and discharges the ink Q onto the paper sheet P through the nozzles, thereby recording information on the paper sheet P. The controller in the printer10includes a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and a storage unit, all of which are not illustrated. The controller controls the operations of individual sections in the record system1, such as the transporting of the paper sheets P in the record system1, the recording of information in the recording section18, and the postprocess performed by the postprocessing apparatus30.

The postprocessing apparatus30includes an apparatus main body32, an ejection tray33, the stacking unit34, and a stapler61. The stacking unit34is an example of a medium stacking apparatus; the stapler61is an example of a processing section. The apparatus main body32receives the paper sheets P transported from the printer10. The apparatus main body32houses the stacking unit34, the stapler61, and a transport route TB along which the paper sheets P are to be transported.

As illustrated inFIG.2, the stacking unit34includes a processing tray42, an alignment section60, a transport section44, and a moving section58. The stacking unit34further includes a guide member35, a press member36, a flap37, and an ejection roller38. In this embodiment, the direction in which a paper sheet P is to be transported by the stacking unit34is defined as a +A direction, which may be orthogonal to the ±X directions as viewed from the +Z direction and may intersect the ±Y directions as viewed from the +X direction. In addition, a straight line extending in the +A direction is angled with respect to each of straight lines extending in the +Y and +Z directions. For the straight line extending in the +A direction, the +Y-directional end is closer to the −Z-side on the page ofFIG.2than the −Y-directional end thereof is, as viewed from the +X direction. The directions orthogonal to the +A direction as viewed from the +X direction are defined as ±B directions. Hereinafter, the direction in which a paper sheet P is transported toward the alignment section60is defined as the +A direction, whereas the direction in which the paper sheet P is transported away from the alignment section60is defined as the −A direction. The +A direction is an example of a transport direction of a paper sheet P. Moreover, the direction in which the paper sheets P are stacked on the processing tray42is defined as the +B direction, whereas the direction opposite to the +B direction is defined as the −B direction.

The guide member35, which forms a portion of the transport route TB, extends toward the processing tray42. The press member36is disposed so as to be pivotable around a shaft36A extending in the +X direction. The press member36presses a paper sheet P against the processing tray42(described later) by pushing a center PC (seeFIG.4) of the paper sheet P in the −B direction.

The flap37is disposed in substantially parallel with the alignment section60so as to be pivotable around the shaft37A extending in the +X direction. The flap37presses a paper sheet P against the processing tray42by pushing a leading edge PF of the paper sheet P in the −B direction. The ejection roller38rotates to feed a paper sheet stack PT placed on the processing tray42to the ejection tray33. The paper sheet stack PT is formed by the stapler61performing a stapling process on a plurality of paper sheets P stacked on the processing tray42.

As illustrated inFIG.3, the processing tray42is an example of a placement section to which a paper sheet P on which information has been recorded by the recording section18(seeFIG.1) is to be transported. On the processing tray42, paper sheets P are stacked. The processing tray42may be formed of a flat plate having a predetermined thickness in the +B direction, with its length in the +X direction being greater than that of a paper sheet P in the +X direction. The processing tray42has a placement surface43on the +B-directional side, on which paper sheets P are to be placed. In this case, the placement surface43is substantially parallel to the A-X plane.

A placement area S is a virtual region that contains a portion of the processing tray42and some components disposed on the processing tray42. The placement area S is substantially equal to the area of the maximum allowable size of paper sheets P to be placed on the processing tray42. In short, the placement area S is formed on the surface of the processing tray42. The placement area S is defined by the imaginary line inFIG.3. A paper sheet P is transferred to the processing tray42and placed within the placement area S. In this case, the line that passes through the center of the placement area S in the +A direction is defined as a central line C.

As illustrated inFIG.2, the transport section44transports a paper sheet P from the processing tray42to an alignment section60(described later). The transport section44includes a feed roller46, a pair of first paddles48, a first driver52, a pair of second paddles54, and a second driver56, for example. The feed roller46rotates to feed a paper sheet P that has been transported along the guide member35to the processing tray42.

The first paddles48are disposed so as to face, in the −B direction, an upstream portion of the processing tray42in the +A direction. The first paddles48share a rotational shaft49extending in the +X direction and each include three blades51, for example. The blades51, each of which may be a rectangular plate having a predetermined thickness in its rotational direction and made of a rubber material, are arranged with a predetermined spacing therebetween in the +X direction. The first paddles48transport a paper sheet P to the alignment section60.

The first driver52includes a motor and a gear, both of which are not illustrated, and operates under the control of the above controller. The first driver52rotates the first paddles48to bring the blades51into contact with the paper sheet P, thereby transporting the paper sheet P to the alignment section60along the processing tray42.

The second paddles54are disposed so as to face, in the −B direction, a downstream portion of the processing tray42in the +A direction. The second paddles54share a rotational shaft55extending in the +X direction and each include three blades57, for example. The blades57, each of which may be a rectangular plate having a predetermined thickness in its rotational direction and made of a rubber material, are arranged at a predetermined spacing therebetween in the +X direction. The second paddles54transport the paper sheet P to the alignment section60.

The second driver56includes a motor and a gear, both of which are not illustrated and operates under the control of the controller. The second driver56rotates the second paddles54to bring the blades57into contact with the paper sheet P, thereby transporting the paper sheet P to the alignment section60along the processing tray42.

The moving section58can move a plurality of paper sheets P stacked on the processing tray42in the ±X directions, which intersect the +A direction. The moving section58includes a first cursor59A and a second cursor59B (seeFIG.3), for example. Portions of the first cursor59A and the second cursor59B are movable in the ±X directions along the processing tray42. Both of the first cursor59A and the second cursor59B may be driven by a driver (not illustrated) so that they can automatically move in the ±X directions. The first cursor59A and the second cursor59B align both the X-directional edges of a plurality of paper sheets P that have been stacked on the processing tray42. More specifically, the first cursor59A and the second cursor59B move in the ±X directions while putting a paper sheet P or a paper sheet stack PT therebetween, thereby moving the paper sheet P or the paper sheet stack PT in the ±X directions.

The stapler61is an example of a processing section that processes a plurality of paper sheets P stacked on the processing tray42. The stapler61is disposed downstream of the processing tray42in the +A direction. A portion of the stapler61is disposed in line with the alignment section60in the +X direction. More specifically, the stapler61may perform a stapling process by which a predetermined number of paper sheets P are fastened together and then ejects the paper sheet stack PT to the ejection tray33. In addition to or instead of the stapling process, the stapler61may perform a punching process by which punch holes are formed in paper sheets P, a creasing process by which the paper sheets P are creased, a cutting process by which the paper sheets P are cut out, a folding process by which the paper sheets P are folded, and an attaching process by which the paper sheets P are attached together.

As illustrated inFIG.3, the alignment section60includes two side alignment sections62and a center alignment section76, for example. The center alignment section76is disposed on the +A-directional side of the processing tray42. In addition, the center alignment section76is positioned on the central line C with its ±X-directional sides being symmetric to each other with respect to the central line C.

Both of the side alignment sections62are disposed on the +A-directional side of the processing tray42and arranged on the +X-directional and −X-directional sides, respectively, of the center alignment section76. The side alignment sections62are positioned so as to be able to align corners PE, in the +X direction, of leading edges PF of a plurality of paper sheets P. The side alignment sections62are arranged symmetrically with respect to the central line C. Hereinafter, only one of the side alignment sections62will be mainly described, and the description of the other will be sometimes skipped. In this embodiment, the alignment refers to the alignment of the leading edges PF, in the +A direction, of paper sheets P that have been stacked in the +B direction.

As illustrated inFIG.4, each side alignment section62includes a first friction member64, a second friction member66, and a mounting member68, for example. The first friction member64may be made of a corkboard having a predetermined thickness in the +A direction. The −A-directional side of the first friction member64is provided with a first alignment surface65. In short, the first friction member64possesses the first alignment surface65. The first alignment surface65is formed into a planar shape substantially parallel to the X-B plane and has a first friction coefficient μ1 for contact with a paper sheet P.

The second friction member66may be formed into a planar shape having a predetermined thickness in the +A direction. The second friction member66may be made of stainless steel. The second friction member66is thicker in the +A direction than the first friction member64. The −A-directional side of the second friction member66is provided with a second alignment surface67. In short, the second friction member66possesses the second alignment surface67. The second alignment surface67is formed into a planar shape substantially parallel to the X-B plane and disposed on the second friction member66attached to the mounting member68. The second alignment surface67has a second friction coefficient μ2 for contact with the paper sheet P, which is lower than the above first friction coefficient μ1.

As illustrated inFIG.5, the mounting member68may be formed by bending a metal sheet several times. The mounting member68includes: a fixture69secured to the processing tray42; a lower wall71extending from the fixture69in the +A direction; a vertical wall72extending from the lower wall71in the +B direction; and an upper wall73extending from the vertical wall72in the −A direction. The lower wall71has an upper surface71A on the +B-directional side, which is disposed upstream of the placement surface43in the +A direction while being flush with the placement surface43in the +B direction. It should be noted that the illustration of the second paddles54(seeFIG.2) is omitted inFIG.5.

The length of the vertical wall72in the +B direction is greater than the height of a maximum allowable number of paper sheets P to be stacked on the processing tray42. Each pair of the first friction member64and the second friction member66is attached to a mounting surface72A on the −A-directional side of the vertical wall72while being arranged side by side in the +X direction. Each pair of the first friction member64and the second friction member66may be attached with a double-sided tape.

As illustrated inFIG.6, the vertical wall72may be shorter in the +X direction than the lower wall71. The lower wall71has two notches75on its +A-directional side; the notches75are arranged on the ±X-directional ends. It should be noted that only the side alignment section62on the −X-directional side is illustrated inFIG.6. Likewise, the upper wall73has two notches75.

The first friction member64has a substantially H-shaped outline as viewed from the +A direction. The first friction member64includes: a base64A attached to the vertical wall72; two extension portions64B extending from the base64A; and two recess64C, for example. The base64A is formed into a rectangular shape with its length in the +B direction being greater than its length in the +X direction. The extension portions64B are each formed into a sheet shape and extend in the +B directions, respectively, on the −X-directional side of the base64A. The extension portions64B are inserted into the corresponding notches75of the lower wall71and the upper wall73.

The recesses64C are formed in the first friction member64at respective locations where the ±B-directional sides of the base64A are coupled to the +X-directional side surfaces of the extension portions64B. Each recess64C is formed into a semicircular shape as viewed from the +A direction. Each recess64C serves as a clearance when the first friction member64is attached to the vertical wall72. Forming the recesses64C in this manner helps to attach the first friction member64to the vertical wall72.

When the first friction member64is attached to the vertical wall72, a gap may be created between the upper surface71A and the −B-directional side of the portion of the base64A which is positioned upstream of the recess64C in the +X direction. In a comparative example in which the extension portion64B is not formed, the leading edge PF (seeFIG.4) of a paper sheet P may be partly caught inside the gap. In this embodiment, however, the extension portion64B extends so as to pass through the upper surface71A in the −B direction, which blocks the leading edge PF of the paper sheet P from being caught inside the gap between the base64A and the upper surface71A. In short, this configuration reliably brings the leading edge PF of the paper sheet P into contact with the first friction member64, thereby suppressing the leading edge PF from being caught inside the gap between the base64A and the upper surface71A. It should be noted that the extension portion64B on the +B-directional side is effective likewise.

The second friction member66has a substantially H-shaped outline as viewed from the +A direction. The second friction member66includes: a base66A attached to the vertical wall72; two extension portions66B extending from the base66A; and two recess66C, for example. The base66A is formed with its length in the +B direction being greater than its length in the +X direction. The extension portions66B are each formed into a sheet shape and extend in the +B directions, respectively, on the +X-directional side of the base66A. The extension portions66B are inserted into the corresponding notches75of the lower wall71and the upper wall73.

The recesses66C are formed in the second friction member66at respective locations where the ±B-directional sides of the base66A are coupled to the −X-directional side surfaces of the extension portions66B. Each recess66C is formed into a semicircular shape as viewed from the +A direction. Each recess66C serves as a clearance when the second friction member66is attached to the vertical wall72. Forming the recesses66C in this manner helps to attach the second friction member66to the vertical wall72. The extension portions66B produce substantially the same effect as the extension portion64B, more specifically suppresses the leading edge PF of a paper sheet P from being caught inside the gap. Thus, details of the effects of the extension portion66B will not be described. In this embodiment, the recesses64C are formed larger than the recesses66C due to a difference in formability.

FIG.7illustrates locations, in the +A direction, of the respective surfaces of a side alignment section62and the center alignment section76arranged side by side in the X direction. The center alignment section76includes a third friction member78and a mounting member82, for example. The third friction member78may be made of a planar corkboard having a predetermined thickness in the +A direction. The third friction member78has a third alignment surface79on the −A-directional side, which is formed into a planer shape substantially parallel to the X-B plane. The third alignment surface79has a third friction coefficient μ3 for contact with a paper sheet P, which is higher than the second friction coefficient μ2 and may be substantially the same as the first friction coefficient μ1.

The mounting member82may be formed by bending a metal sheet several times so that its length in the +X direction becomes greater than the length of the mounting member68in the +X direction. The mounting member82has substantially the same dimensions as the mounting member68as viewed from the +X direction and is partly secured to the processing tray42(seeFIG.2). The mounting member82has a vertical wall84extending in the +B direction. The vertical wall84may be formed into a planar shape having a predetermined thickness in the +A direction. The third friction member78is attached to a mounting surface84A formed on the −A-directional side of the vertical wall84with a double-sided tape, for example.

As illustrated inFIGS.4,7, and8, L1≈L2is satisfied, where L1denotes the length (mm) of the first alignment surface65in the +X direction, and L2denotes the length (mm) of the second alignment surface67in the +X direction. In addition, L3>L1and L3>L2are satisfied, where L3denotes the length (mm) of the third alignment surface79in the +X direction. The first alignment surface65is disposed upstream of the third alignment surface79in the +A direction. The second alignment surface67is disposed upstream of the first alignment surface65in the +A direction and closer to the center of the placement area S (seeFIG.3) in the +X direction than the first alignment surface65is. The third alignment surface79is disposed closer to the center in the +X direction than the second alignment surface67is and downstream of the second alignment surface67in the +A direction.

As described above, the alignment section60includes two first alignment surfaces65and two second alignment surfaces67, for example. The first alignment surfaces65are arranged on the ±X-directional sides, respectively, of the placement area S so as to be symmetric to each other with respect to the central line C (seeFIG.3). Likewise, the second alignment surfaces67are arranged on the ±X-directional sides, respectively, of the placement area S so as to be symmetric to each other with respect to the central line C.

As illustrated inFIG.7, the location of the second alignment surface67in the +A direction is denoted by P1; the location of the first alignment surface65in the +A direction is denoted by P2; the location of the third alignment surface79in the +A direction is denoted by P3; the location of the mounting surface72A in the +A direction is denoted by P4; and the location of the mounting surface84A in the +A direction is denoted by P5. In this case, the locations P1, P2, P3, P4, and P5may be arranged in this order from the upstream side in the +A direction. However, the distances between the locations P1, P2, P3, P4, and P5may be different from one another in the +A direction.

As illustrated inFIG.8, L4=L1+L2may be satisfied, where L4denotes the length (mm) of the vertical wall72in the +X direction. The −X-directional side surface of the first friction member64may be in contact with the +X-directional side surface of the second friction member66, with the first alignment surface65being shifted from the second alignment surface67as viewed from the +A direction, namely, with a step77being formed between the first friction member64and the second friction member66. The cross-section of each of the first friction member64and the second friction member66taken along the X-A plane has a rectangular shape with its length in the +X direction being greater than its length in the +A direction. Furthermore, the downstream edge of the paper sheet P in the +A direction corresponds to the leading edge PF; the angle between the leading edge PF and the X-axis is defined as an angle θ (deg).

Suppose the uppermost one of a plurality of paper sheets P stacked on the processing tray42(seeFIG.3) is transported to the alignment section60inside the space where neither the first alignment surfaces65nor the second alignment surfaces67is present. In this case, the uppermost paper sheet P forms an angle θ=θ1 (deg) with the X-axis, and the length of the first alignment surface65in the +X direction is the length L1. Hereinafter, the expression “the movement of the uppermost paper sheet P into the space between the other paper sheets P and the alignment section60” is referred to as the unexpected entry of the paper sheet P.

The amount by which the second alignment surface67is shifted from the first alignment surface65in the +A direction is defined as a length L5(mm), which can be expressed as L5=(L1)×tan θ1. When the paper sheet P comes into contact with a pair of a first friction member64and a second friction member66while forming the angle θ1 with the X-axis, the arrangement of the first friction member64and the second friction member66act to decrease the angle θ1. This configuration is effective in suppressing the unexpected entry of the paper sheet P.

As illustrated inFIG.9, the first alignment surface65may have uniform surface roughness in the +B direction. In other words, the first friction coefficient μ1 of the first alignment surface65is entirely higher than the second friction coefficient μ2 of the second alignment surface67in the +B direction.

Next, a description will be given below of functions and effects of the stacking unit34and the postprocessing apparatus30in the record system1according to the first embodiment. When some components of the record system1which have already been explained are described again, the numbers of the figures to be referenced will not be described.

With reference toFIG.10, a description will be given below regarding a case where the transport section44(seeFIG.2) transports the uppermost one of a plurality of paper sheets P stacked on both the processing tray42and the lower wall71to the alignment section60. InFIG.10, only one side alignment section62is illustrated, and the illustration of the center alignment section76(seeFIG.3) is omitted.

When the paper sheet P on which information has been recorded with a relatively small amount of ink Q is transported by the transport section44, the paper sheet P is less likely to greatly swell because the amount of ink Q impregnated in the paper sheet P is small. In this case, the paper sheet P does not curl and can maintain its stiffness against external force given in the +A direction. As a result, there is a low possibility that the unexpected entry of the paper sheet P occurs.

When the paper sheet P on which information has been recorded with a relatively large amount of ink Q is transported by the transport section44, the paper sheet P is likely to greatly swell because the amount of ink Q impregnated in the paper sheet P is large. In this case, the paper sheet P may curl and fail to maintain its stiffness against external force applied in the +A direction. As a result, the angle θ that the leading edge PF of the paper sheet P being transported to the alignment section60forms with the X-axis might increase.

When the paper sheet P reaches the alignment section60while angled with respect to the X-axis, a portion of the leading edge PF of the paper sheet P in the +A direction comes into contact with the first alignment surface65of the first friction member64. Then, when the leading edge PF of the paper sheet P moves in the −B direction, the first alignment surface65having the first friction coefficient μ1 applies a relatively large friction force to the paper sheet P in the +B direction. This configuration suppresses the leading edge PF of the paper sheet P from unexpectedly entering into the space between the alignment section60and the leading edges PF of the other paper sheets P that have already been stacked.

When the uppermost paper sheet P is further transported, another portion of the leading edge PF of the paper sheet P reaches the alignment section60. In this case, the portion of the leading edge PF of the paper sheet P which has already reached the alignment section60is curled. However, after the paper sheet P has been transported away from the rotating first paddles48and second paddles54, the feeding force acting on the paper sheet P is released. As a result, the curled portion of the paper sheet P which has already reached the alignment section60becomes straight, so that the leading edge PF of the paper sheet P becomes aligned with the X-axis. After that, the paper sheet P is subjected to the stapling process by the stapler61together with other paper sheets P. In this way, the paper sheet stack PT is formed.

As illustrated inFIG.11, the paper sheet stack PT is placed between the first cursor59A and the second cursor59B while all of them are aligned together in the +X direction. When both the first cursor59A and the second cursor59B move in the −X direction, the paper sheet stack PT also moves in the −X direction.

While the paper sheet stack PT is being moved in the −X direction as illustrated inFIG.12, a leading edge PF of the paper sheet stack PT is kept in contact with the second alignment surface67but apart from the first alignment surface65because the second alignment surface67is shifted from the first alignment surface65as viewed from the +B direction. Thus, when the paper sheet stack PT is moved in the −X direction, this movement is not prohibited by the first friction member64because the first friction member64does not generate a relatively large friction force. It should be noted that, when the paper sheet stack PT is moved in the +X direction, the same effect is produced.

Suppose an uppermost one (referred to below as the uppermost paper sheet PA) of a plurality of paper sheets P stacked on the processing tray42is transported to the alignment section60over the paper sheets P, as described above. Further, the uppermost paper sheet PA is warped. According to the stacking unit34in the first embodiment, when transported to the alignment section60by the transport section44, the uppermost paper sheet PA may be angled with respect to a straight lines extending in the +A or +X direction. Following this, a portion of the downstream, leading edge PF of the angled uppermost paper sheet PA might come into contact with a first alignment surface65and then unexpectedly move toward the processing tray42. In this case, however, the first alignment surface65, the first friction coefficient μ1 of which is higher than the second friction coefficient μ2 of the second alignment surface67, applies a relatively large friction force to the portion of the leading edge PF in the direction opposite to the moving direction. Therefore, this configuration can suppress the portion of the downstream, leading edge PF from entering into the space between the alignment section60and the leading edges PF of the paper sheets P that have already been stacked.

When the uppermost paper sheet PA is further transported, the portion of the leading edge PF of the uppermost paper sheet PA is curled, and another portion of the leading edge PF reaches substantially the same location as this curled portion in the +A direction. Then, the pressing force that the transport section44has applied to the uppermost paper sheet PA is released so that the angle of the uppermost paper sheet PA is corrected. In this case, the other portion of the leading edge PF is in contact with the second alignment surface67. Since the second alignment surface67is positioned upstream of the first alignment surface65in the +A direction, the leading edge PF of the uppermost paper sheet PA comes off the first alignment surface65and, in turn, comes into contact with the second alignment surface67during the correction of the angle of the uppermost paper sheet PA. As a result, portions of the leading edges PF of the paper sheets P, including the uppermost paper sheet PA, stacked on the processing tray42come into contact with the second alignment surface67.

When the moving section58moves the plurality of paper sheets P including the uppermost paper sheet PA in the +X or −X direction, the second alignment surface67, the second friction coefficient μ2 of which is lower than the first friction coefficient μ1 of the first friction member64, applies a relatively small friction force to the leading edges PF of the paper sheets P in the direction opposite to the moving direction. Thus, the moving section58can move the paper sheets P in the ±X directions with only a light load placed on the paper sheets P. Furthermore, the stacking unit34can be formed with a simple configuration because it is unnecessary to move the first alignment surfaces65or the second alignment surfaces67.

According to the stacking unit34, when the paper sheet P is further transferred in the +A direction after the leading edge PF of the paper sheet P has come into the second alignment surface67, the center PC, in the +X direction, of the leading edge PF of the paper sheet P comes into contact with the third alignment surface79. In this case, even if the leading edge PF of the paper sheet P moves toward the processing tray42, the third alignment surface79, the third friction coefficient μ3 which is higher than the second friction coefficient μ2 of the second alignment surface67, applies a relatively large friction force to the center PC of the leading edge PF of the paper sheet P in the direction opposite to the moving direction. Therefore, this configuration can suppress the leading edge PF of the paper sheet P from entering into the space between the third alignment surface79and the leading edges PF of the paper sheets P that have already been stacked. Moreover, since the third alignment surface79is disposed downstream of the second alignment surfaces67in the +A direction, the paper sheets P come into contact with the third alignment surface79less frequently than the second alignment surfaces67. Therefore, the moving section58can move the plurality of paper sheets P in the ±X directions under only a light load.

When a paper sheet P is angled with respect to a straight line extending in the +A direction, one corner PE of the leading edge PF of the paper sheet P is transported ahead of the other corner PE thereof and is positioned downstream of the center PC of the leading edge PF of the paper sheet P in the +A direction. In other words, the downstream corner PE of the leading edge PF of the angled paper sheet P is positioned ahead of the center PC thereof in the +A direction. According to the stacking unit34, the first alignment surfaces65are positioned upstream of the third alignment surface79in the +A direction. The downstream corner PE of the leading edge PF of the paper sheet P thus comes into contact with the first alignment surface65having a relatively high friction coefficient earlier than when the center PC thereof comes into contact with the third alignment surface79having a relatively low friction coefficient. This configuration can suppress the paper sheet P from entering into the space between the first alignment surface65and the leading edges PF of paper sheets P that have already been stacked. Moreover, when the moving section58moves the plurality of paper sheets P in the +X or −X direction after the angle of the paper sheet P has been corrected by bringing the leading edge PF into contact with the first alignment surface65, these paper sheets P come into contact with the second alignment surface67having a relatively low friction coefficient. Therefore, the moving section58can move the paper sheets P in the ±X directions under only a light load.

According to the stacking unit34, even when the paper sheet P being transferred to the alignment section60is angled, the leading edge PF of the paper sheet P can reliably come into contact with the first alignment surface65and the second alignment surface67in this order, independently of its angled orientation, more specifically regardless of which corner PE, in the +X direction, of the leading edge PF of the paper sheet P is positioned ahead. Moreover, according to the stacking unit34, the first friction coefficient μ1 of the first alignment surface65is higher than the second friction coefficient μ2 of the second alignment surface67at least in the +B direction. It is thus possible to suppress the downstream, leading edge PF of the paper sheet P from entering into the space between the alignment section60and the leading edge PF of the paper sheets P that have already been stacked on the processing tray42. Therefore, the paper sheet P being transported to the processing tray42does not affect the alignment of the leading edges PF of the paper sheets P that has already been stacked.

According to the stacking unit34, the first friction members64provided with the respective first alignment surfaces65are replaceable. Thus, when one of the first alignment surfaces65is worn out, it is only necessary to replace the corresponding first friction member64without replacing the entire alignment section60. It is consequently possible to avoid discarding many components in the process of replacing the first alignment surfaces65. Likewise, according to the stacking unit34, the second friction members66provided with the second alignment surfaces67are replaceable. Thus, when one of the second alignment surfaces67is worn out, it is only necessary to replace the corresponding second friction member66without replacing the entire alignment section60. It is consequently possible to avoid discarding many components in the process of replacing the second alignment surface67.

According to the postprocessing apparatus30, the moving section58can move the plurality of paper sheets P in the ±X directions with only a light load placed on the paper sheets P, thereby reducing the risk of the paper sheets P being distorted.

Second Embodiment

Next, a description will be given below of a record system1, a postprocessing apparatus30, and a stacking unit90according to a second embodiment with reference to some accompanying drawings. A stacking unit90in the second embodiment differs from the stacking unit34(seeFIG.7) in the foregoing first embodiment, in the positional relationship between a first alignment surface65and a third alignment surface79. Other components in the second embodiment are substantially the same as those in the first embodiment. Those components are given the identical reference numbers and will be described with reference to theFIGS.1to12.

In the second embodiment, as illustrated inFIG.13, the third alignment surface79is disposed upstream of the first alignment surface65in the +A direction. More specifically, locations P1, P3, P2, P5, and P4, which correspond to those described in the first embodiment (seeFIG.7), are arranged in this order from the upstream side in the +A direction.

A function and effect of the stacking unit90in the second embodiment will be described below. However, functions and effects of the record system1and the postprocessing apparatus30in the second embodiment will not be described below because they are substantially the same as those in the first embodiment. When a paper sheet P being transferred toward an alignment section60is not angled or is slightly angled, a center PC of the leading edge PF of the paper sheet P in the +X direction may be positioned downstream of a corner PE thereof in the +A direction after a leading edge PF of the paper sheet P in the +A direction has come into contact into a second alignment surface67. According to the stacking unit90in the second embodiment, the third alignment surface79is positioned upstream of the first alignment surface65in the +A direction. The center PC of the leading edge PF of the paper sheet P being transported ahead of the corner PE thus comes into contact with the third alignment surface79having a relatively high friction coefficient earlier than the corner PE does. This configuration can suppress the paper sheet P from entering into the space between the third alignment surface79and leading edges PF of paper sheets P that have already been stacked. Moreover, when a moving section58(seeFIG.2) moves the plurality of paper sheets P in the +X or −X direction after the angle of the paper sheet P has been corrected by bringing the leading edge PF of the paper sheet P into contact with the third alignment surface79, the paper sheets P come into contact with the second alignment surface67having a relatively low friction coefficient. As a result, the moving section58can move the paper sheets P under only a light load.

Third Embodiment

Next, a description will be given below of a record system1, a postprocessing apparatus30, and a stacking unit94according to a third embodiment with reference to some accompanying drawings. A stacking unit94in the third embodiment differs from the stacking unit34in the foregoing first embodiment because the stacking unit94is provided with a side alignment section96instead of the side alignment section62(seeFIG.7). Other components in the third embodiment are substantially the same as those in the first embodiment. Those components are given the identical reference numbers and will be described with reference to theFIGS.1to12.

As illustrated inFIG.14, the side alignment section96in the third embodiment includes a first friction member64and a mounting member98, for example. It should be noted that only the side alignment section96disposed on the +X-directional side will be illustrated and described below, and the illustration and description of the side alignment section96disposed on the opposite side are omitted. The mounting member98may be formed by bending a stainless steel plate several times. The mounting member98includes a vertical wall99, which corresponds to the vertical wall72(seeFIG.7) of the mounting member68. Other components of the mounting member98are substantially the same as those of the mounting member68.

The vertical wall99is curved at right angles at two points as viewed from the +B direction. The vertical wall99includes a mounting surface102, a side surface103, and a second alignment surface104. In short, the second alignment surface104is formed on the mounting member98. The mounting surface102, which is substantially parallel to the X-B plane, may be attached to the first friction member64with a double-sided tape (not illustrated); the side surface103extends in the −A direction from the −X-directional side of the mounting surface102. The second alignment surface104, which is substantially parallel to the X-B plane, extends in the −X direction from the −A-directional side of the side surface103. The second alignment surface104has a second friction coefficient μ2 for contact with a paper sheet P.

A function and effect of the stacking unit94in the third embodiment will be described below. However, functions and effects of a record system1and a postprocessing apparatus30in the third embodiment will not be described below because they are substantially the same as those in the first embodiment. According to the stacking unit94, the second alignment surface104is formed on the mounting member98. Therefore, the stacking unit94can be fabricated without performing a process of attaching a member provided with the second alignment surface104to the mounting member98.

Examples of the medium stacking apparatuses and the postprocessing apparatuses according to the first to third embodiments of the present disclosure basically include the components described above. However, it is obvious that some of those components can be modified, replaced, or omitted without departing from the spirit of present disclosure in this application.

First Modification

As illustrated inFIG.15, a side alignment section110may be formed as in a first modification of the foregoing first embodiment. The side alignment section110differs from the side alignment section62(seeFIG.7) in the first embodiment. More specifically, a first friction member64in the first modification is formed longer than that in the +X direction, and a second friction member66in the first modification is thinner than that in the first embodiment. The second friction member66is attached to the −X-directional half side of the −A-directional surface of the first friction member64. In this way, the second friction member66may be attached to the first friction member64.

Second Modification

As illustrated inFIG.16, a side alignment section112may be formed as in a second modification of the foregoing first embodiment. The side alignment section112differs from the side alignment section62(seeFIG.7) in the first embodiment, in including a projection114formed on the +X-directional side of a second friction member66. The projection114may be a sheet-shaped portion that protrudes in the +X direction from the +X- and −A-directional surfaces of the second friction member66. The projection114covers the interface between a first friction member64and the second friction member66from the −A-directional side. The second friction member66may be attached to both the first friction member64and a mounting member68.

Third Modification

As illustrated inFIG.17, a first alignment surface65and a second alignment surface67are arranged so as to reserve a spacing therebetween in the +X direction, as in a third modification of the foregoing first embodiment. In this case, the direction between the +X-directional side of the first alignment surface65and the +X-directional side of the second alignment surface67is defined as a length L6(mm); a paper sheet P forms an angle θ=θ1 (deg) with the X-axis. This configuration can suppress the unexpected entry of the paper sheet P as long as length L5≤(length L6)×tan θ1 is satisfied. The configuration can suppress the first friction member64and the second friction member66from abutting against each other, even if a considerable manufacturing error arises upon the attaching of a first friction member64and a second friction member66to a mounting member68. This is because the first alignment surface65is kept apart from the second alignment surface67in the +X direction. In short, the configuration can reduce the influence of the manufacturing error.

Other Modifications

As for the stacking unit34in the first embodiment, the alignment section60does not necessarily have to include a third friction member78with a third alignment surface79. In addition, the third friction coefficient μ3 may or may not be higher than the first friction coefficient μ1, as long as the third friction coefficient μ3 is higher than the second friction coefficient μ2. Two side alignment sections62do not necessarily have to be disposed on the ±X-directional sides of the processing tray42; alternatively, a single edge alignment section62may be disposed on one of the ±X-directional sides of the processing tray42. The first alignment surfaces65do not necessarily have to have a friction coefficient that is entirely higher than the second friction coefficient μ2 in the +B direction; alternatively, the friction coefficient of the first alignment surfaces65may be partly the same as the second friction coefficient μ2 in the +B direction. Likewise, the friction coefficient of the first alignment surfaces65may also be partly the same as the second friction coefficient μ2 in the +X direction.

If each of the first friction members64, the second friction members66, and the third friction member78is stiff enough to withstand a force acting from the +A direction, they may be directly attached to the processing tray42without using the mounting members68and82. The first alignment surfaces65may be formed on the respective mounting members68. In this case, the first alignment surfaces65may be formed by subjecting the respective vertical walls72to a rough surface treatment.

The third friction member78may have a substantially H-shaped outline as viewed from the +A direction. The corner of each second friction member66closer to the corresponding first friction member64may be formed into a round or tapered shape. This configuration can help paper sheets P move from a first alignment surface65to the next second alignment surface67. Furthermore, each first alignment surface65may be aligned with the third alignment surface79as viewed from the +A direction.

It should be noted that the above modified configurations of the stacking unit34in the first embodiment may also be applicable to both the stacking unit90in the second embodiment and the stacking unit94in the third embodiment.