This patent specification is based on and claims priority from Japanese Patent Application Nos. 2009-132454, filed on Jun. 1, 2009, and 2010-018767, filed on Jan. 29, 2010, in the Japan Patent Office, the contents of which are hereby incorporated by reference herein in their entirety.
1. Field of the Invention
The present invention generally relates to a spine formation device to form a spine of a bundle of folded sheets, a post-processing apparatus including the spine formation device, and a spine formation system including the spine formation device, and an image forming apparatus, such as a copier, a printer, a facsimile machine, or a multifunction machine capable of at least two of these functions.
2. Discussion of the Background Art
Post-processing apparatuses to perform post processing of recording media, such as aligning, sorting, stapling, punching, and folding of sheets, are widely used and are often disposed downstream from an image forming apparatus to perform post-processing of the sheets output from the image forming apparatus. At present, post-processing apparatuses generally perform saddle-stitching along a centerline of sheets in addition to conventional edge-stitching along an edge portion of sheets.
To improve the quality of the finished product, several approaches, described below, for shaping the folded portion of a bundle of saddle-stitched sheets have been proposed. More specifically, when a bundle of sheets (hereinafter “booklet”) is saddle-stitched and then folded in two, its folded portion, that is, a portion around its spine, tends to bulge, degrading the overall appearance of the booklet. In addition, because the bulging spine makes the booklet thicker on the spine side and thinner on the opposite side, when the booklets are piled together with the bulging spines on the same side, the piled booklets tilt more as the number of the booklets increases. Consequently, the booklets might fall over when piled together.
By contrast, when the spine of the booklet is flattened, bulging of the booklet can be reduced, and accordingly multiple booklets can be piled together. This flattening is important for ease of storage and transport because it is difficult to stack booklets together if their spines bulge, making it difficult to store or carry them. With this reformation, a relatively large number of booklets can be piled together.
The bulging spine of the booklet can, for example, be flattened using a pressing member configured to sandwich the portion adjacent to the spine of the booklet and a spine-forming roller configured to roll along that side of the pressing member from which the spine of the booklet protrudes in a longitudinal direction of the spine of the booklet while contacting the spine of the booklet. The spine-forming roller moves at least once over the entire length of the spine of the booklet being fixed by the pressing member while applying to the spine a pressure sufficient to flatten the spine.
However, because only the bulging portion is pressed with the spine-forming roller in this approach, the booklet can wrinkle in a direction perpendicular to the longitudinal direction in which the spine extends, degrading its appearance. In addition, with large sheet sizes, productivity decreases because it takes longer for the spine-forming roller to move over the entire length of the spine of the booklet.
Alternatively, a center portion of the saddle-stitched booklet in a direction in which the booklet is transported (hereinafter “sheet conveyance direction”) may be pushed with a folding plate so that the booklet is sandwiched between a first pair of rollers, thereby forming the spine. With the booklet kept at a predetermined position, a second pair of rollers that move in a direction perpendicular to the sheet conveyance direction presses the folded portion from the side. In this approach, differently from the above-described approach, not the spine in parallel to a thickness direction of the booklet but the portion perpendicular to the spine is pressed, thus increasing the pressure per unit length. As a result, the spine can be shaped better, improving the quality of the booklet.
Although this approach can reduce the damage to the booklet caused by the first method described above, when the number of sheets forming the booklet increases, the folded portion curves gradually from the corners because multiple sheets form a multilayered structure. This phenomenon is particularly noticeable on sheets closer to the front cover. Thus, it is difficult to eliminate bulging of the spine.
In view of the foregoing, the inventors of the present invention recognize that there is a need to reduce bulging of booklets while maintaining productivity so that multiple booklets can be piled together, which known approaches fail to do.
In view of the foregoing, in one illustrative embodiment of the present invention provides a spine formation device to flatten a spine of a bundle of folded sheets. The spine formation device includes a sheet conveyer that conveys the bundle of folded sheets with a folded portion of the bundle of folded sheets forming a front end portion of the bundle of folded sheets, a sandwiching member disposed downstream from the sheet conveyer in a sheet conveyance direction in which the sheet conveyer conveys the bundle of folded sheets, and a spine formation unit disposed downstream from the sandwiching member in the sheet conveyance direction, to flatten the folded portion of the bundle of folded sheets held by the sandwiching member. The sandwiching member squeezes the bundle of folded sheets sandwiched therein in a direction of thickness of the bundle of folded sheets. The bundle of folded sheets is set at a position where folded portion thereof projects by a predetermined length from the sandwiching member in the sheet conveyance direction, and the spine formation unit presses against the folded portion in a reverse direction of the sheet conveyance direction while moving in a direction perpendicular to a longitudinal direction of the folded portion of the bundle of folded sheets.
In another illustrative embodiment of the present invention, a post-processing apparatus includes a saddle-stapler to staple a bundle of sheets together along a centerline of the bundle, a folding unit to fold the bundle of sheets along the centerline of the bundle, and the spine formation device described above.
Yet in another illustrative embodiment of the present embodiment, a spine formation system includes an image forming apparatus, a post-processing apparatus to perform post processing of sheets transported from the image forming apparatus, and the spine formation device described above.
A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
In describing preferred embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent 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 operate in a similar manner and achieve a similar result.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views thereof, and particularly to
It is to be noted that, in the description below, a pair of transport rollers 11 and 12 serve as a sheet conveyer, and first and second clamp members 14 and 15 serve as a sandwiching member. Further, a spine formation roller 16, an elevator unit 27 including a pressure spring 28, and the elevator motor 26 together form a spine formation unit.
The post-processing apparatus 1 includes an entrance path A along which sheets of recording media transported form an image forming apparatus PR to the post-processing apparatus 1 are initially transported, a transport path B leading from the entrance path A to a proof tray 201, a shift tray path C leading from the entrance path A to a shift tray 202, a transport path D leading from the entrance path A to a first processing tray F, a storage area E disposed along the transport path D, and a second processing tray H disposed downstream from the first processing tray F in a direction in which the sheet is transported (hereinafter “sheet conveyance direction”). The spine formation device J is connected to a downstream side of the post-processing apparatus 1 in the sheet conveyance direction. The first processing tray F aligns multiple sheets and staples an edge portion of the aligned multiple sheets as required. The multiple sheets processed on the first processing tray F are stored in the storage area E and then transported to the first processing tray F at a time. The sheets transported along the entrance path A or discharged from the first processing tray F are transported along the shift tray path C to the shift tray 202. The second processing tray H perform folding and/or saddle-stapling, that is, stapling along a centerline, of the multiple sheets aligned on the first processing tray F. Then, the spine formation device J flattens a folded edge (spine) of a bundle of sheets (booklet).
It is to be noted that the post-processing apparatus 1 has a known configuration and performs known operations, which are briefly described below.
The sheets transported to the post-processing apparatus 1 to be stapled along its centerline are stacked on the first processing tray F sequentially. A jogger fence 2 aligns the sheets placed on the first processing tray F in a width direction or transverse direction, which is perpendicular to the sheet conveyance direction. Further, a roller 4 pushes the sheets so that a trailing edge of the sheet contacts a back fence, not shown, disposed an upstream side in the sheet conveyance direction while a release belt, not shown, rotates in reverse so that a leading edge of the sheets is pressed against a back of a release pawl 3 disposed on a down stream side in the sheet conveyance direction, and thus a bundle of sheets are aligned in the sheet conveyance direction. After the sheets are aligned in the sheet conveyance direction as well as in the width direction, the release pawl 3 and a pressure roller 5 turn the bundle of sheets a relatively large angle along a guide roller, not shown, to the second processing tray H.
Then, the bundle of sheets is transported to a reference fence 7 on the second processing tray H, and a center stapling fences 12a and 12b align the sheets in the width direction. Further, the trailing edge of the bundle of sheets is pushed to an aligning pawl 8, and thus the sheets are aligned in the sheet conveyance direction. After the alignment, center staplers 6a and 6b staple the bundle of sheets along its centerline into a booklet as bookbinding. Then, the reference fence 7 pushes a center portion (folded position) of the booklet to a position facing a folding plate 9. The folding plate 9 moves horizontally in
It is to be noted that the spine formation device J may be configured as a spine formation unit removably attached to the post-processing apparatus 1. When the spine formation device J is configured to be removably attached to the post-processing apparatus 1, it is preferable that a pair of discharge rollers be provided along the sheet transport path between the folding rollers 10 to the transport rollers 11 and 12 of the spine formation device J. Alternatively, the spine formation device J may be integrated in or removably attached to the image forming apparatus PR similarly to the post-processing apparatus 1.
A configuration of the spine formation device J is described below with reference to
The spine formation device J includes the pair of transport rollers 11 and 12, the pair of clamp members 14 and 15 (e.g., a first clamp member 14 and a second clamp member 15), the spine formation roller 16, a pair of discharge rollers 20, and a discharge tray 21, which are disposed in that order along the sheet conveyance direction. An axis of rotation of the spine formation roller 16 parallels or substantially parallels a longitudinal direction of a folded portion 30a of a booklet 30. The spine formation roller 16 moves along guide surfaces 14c and 15c of the clamp members 14 and 15, respectively, on the downstream side in the sheet conveyance direction.
Additionally, guide plates 22 and 23, serving as a sheet guide, to guide the booklet 30 are provided above the spine formation roller 16 in
It is to be noted that, in
The transport rollers 11 and 12 transport the booklet 30 sandwiched therebetween by rotating, and the folded portion forms a front end portion of the booklet 30. After the leading-edge detector 13 detects the leading-edge portion 30a of the booklet 30, the transport rollers 11 and 12 transport the booklet 30 to a predetermined position where the leading-edge portion 30a projects from the guide surfaces 14c and 15c of the clamp members 14 and 15 by a predetermined length (projection length d).
The transport rollers 11 and 12 are driven by a motor, not shown, which is controlled by a central processing unit (CPU) 111 of a control circuit or control unit 110 shown in
As shown in
The clamp members 14 and 15 can move closer to and away from each other and sandwich therebetween the booklet 30 that has transported to the predetermined position by the transport rollers 11 and 12, thereby fixing the position of the booklet 30. As a driving mechanism to move the clamp members 14 and 15, for example, a gear deceleration mechanism or a hydraulic driving mechanism can be used although not shown in figures.
Referring to
The spine formation roller 16 deforms, that is, flattens the leading-edge portion or folded portion 30a of the booklet 30 to shape it into the spine of the booklet 30. As shown in
When pressed against the spine formation roller 16, the folded portion 30a can escape to the chamfered portions 14d and 15d, that is, the chamfered portions 14d and 15d can accommodate the portion extended in the thickness direction of the booklet 30 due to flattening. As shown in
It is to be noted that, in
With this configuration, regardless of steps formed by the first and second clamp members 14 and 15, the spine formation roller 16 can flatten the folded portion 30a projecting from the first and second clamp members 14 and 15 by the predetermined projection length (projection length d in
Referring to
Referring to
In this state, as shown in
It is to be noted that the predetermined projection length d is set according to the number of sheets bundled together, which is described later with reference to
When the spine formation roller 16 has passed the leading-edge portion 30a of the booklet 30 and reaches a position shown in
It is to be noted that, if the leading-edge portion 30a is not flattened sufficiently, the spine formation roller 16 can reciprocate across the leading-edge portion 30a multiple times until the leading-edge portion 30a is fully flattened. To facilitate flattening of the spine, as described above, the chamfered portions 14d and 15d are formed on the downstream corners of the clamp members 14 and 15 in the sheet conveyance direction, and overflowing portions in the thickness direction can escape to the chamfered portions 14d and 15d. Thus, the leading-edge portion 30a can be flattened and serve as the spine of the booklet 30. After the spine formation, the discharge rollers 20 discharge the booklet 30 onto the discharge tray 21.
It is to be noted that the number of reciprocal movements (hereinafter “reciprocation number”) of the spine formation roller 16, that is, how many times the spine formation roller 16 moves back and forth, can be set according to one of multiple predetermined variables relating to the booklet 30, such as, the number of sheets, the thickness of the booklet 30, direction of grain of sheets, rigidity of sheets, and the like.
Additionally, because the spine formation roller 16 moves up and down in
It is to be noted that, as shown in
Referring to
The elevator unit 27 includes a pair of rollers 27a and 27b disposed in a lower end portion and an upper end portion of the elevator unit 27, respectively, and the rollers 27a and 27b project from both the front side and the back side of the elevator unit 27.
The rollers 27a and 27b movably engage a slot 25a formed in a front plate and a back plate of a frame 25 of the spine formation device J. With this configuration, the elevator unit 27 can descend and ascend along a predetermined path, guided by the slot 25a. The elevator unit 27 further includes a rack 27c disposed on an edge surface in parallel to the slot 25a, opposite the side where the spine formation roller 16 is disposed, and a gear 26a attached to an output shaft of the elevator motor 26 engages the rack 27c. With this configuration, rotation of the gear 26a is converted to a linear movement of the rack 27c so that the elevator unit 27 can move vertically in
A home position of the elevator unit 27 is set to a position where the guide plates 22 and 23 corresponds to the gap between the clamp members 14 and 15 so that the guide plates 22 and 23 can guide the booklet 30 discharged from the clamp members 14 and 15. In
Additionally, although the pressure spring 28 shown in
As shown in
In
In
At S302, when the sheets of the booklet 30 are thinner sheets, for example, sheets having a unit weight of 110 g/m2 or less (YES at S302), at S303 the control unit 110 sets the reciprocation number of the spine formation roller 16 to a first number N1. When the sheets of the booklet 30 are standard sheets, for example, sheets having a weight within a range from 110 g/m2 to 130 g/m2, (YES at S304), at S305 the control unit 110 sets the reciprocation number of the spine formation roller 16 to the second number N2. When the sheets of the booklet 30 are thicker sheets, for example, sheets having a weight greater than 130 g/m2, at S306 the control unit 110 sets the reciprocation number of the spine formation roller 16 to the third number N3. Then, at S307 the spine formation is performed and at S309 the booklet 30 is discharged. By contrast, when the spine formation is not to be performed (NO at S301), spine formation is not performed at S308 and then the booklet 30 is discharged at S309.
In
In
It is to be noted that rigidity of sheets can be quantified through, for example, folding tests of the sheets, and reference degrees of rigidity used in the present embodiment can be set experimentally.
Regarding the predetermined projection lengths A, B, and C, A<B<C is satisfied, and regarding the reciprocation numbers N1, N2, and N3, N1<N2<N3 is satisfied. Actual projection lengths and actual reciprocation numbers can be set experimentally for each device.
Thus, in an illustrative embodiment, the spine formation device J includes a pair of transport rollers 11 and 12 to transport the booklet 30 with the folded portion on the front side or leading side, the first and second clamp members 14 and 15 to sandwich and squeeze the booklet 30 in the direction of thickness of the booklet 30, and the elevator unit 27 including the spine formation roller 16 to flatten the leading-edge portion 30a, thereby forming the spine of the booklet 30. The transport rollers 11 and 12 transport the booklet 30 to a position where the leading-edge portion 30a projects from the clamp members 14 and 15 by a predetermined projection length d, and the spine formation roller 16 moves in the direction perpendicular to the longitudinal direction of the leading-edge portion 30a held at that position. While thus rotating, the spine formation roller 16 presses against the leading-edge portion 30a to the upstream side in the direction in which the booklet 30 is transported.
As described above, in the present embodiment, a portion around the leading-edge of the booklet 30 is sandwiched by the clamp members 14 and 15, and the spine formation roller 16 having a shaft parallel to the leading-edge portion 30a (folded portion) of the booklet 30 moves in a direction perpendicular to the longitudinal direction of the leading-edge portion 30a, thereby pressing the leading-edge portion 30a. Therefore, the spine of the booklet 30 can be flattened in a shorter time. At that time, because the clamp members 14 and 15 sandwich the leading-edge portion 30a therebetween with a predetermined pressure, bulging of the portion around the leading-edge portion 30a can be prevented.
Additionally, because the chamfered portions 14d and 15d can accommodate the portions of the leading-edge portion 30a overflowing to the front side and the back side of the booklet 30 due to flattening, the leading-edge portion 30a can become flat relatively easily and reliably. Thus, a booklet with a square spine can be produced, and many booklets can be piled together because bulging of the booklet is reduced.
Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the disclosure of this patent specification may be practiced otherwise than as specifically described herein.
Number | Date | Country | Kind |
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2009-132454 | Jun 2009 | JP | national |
2010-018767 | Jan 2010 | JP | national |