Patent Application
20110031673
Embodiments described herein relate generally to a sheet finishing apparatus and a sheet finishing method.
Hitherto, a sheet finishing apparatus is known which is disposed downstream of an image forming apparatus, such as a copying machine, a printer or an MFP (Multi-Functional Peripheral), performs finishing, such as folding or stitching, on a printed sheet and forms a booklet.
This kind of sheet finishing apparatus is usually provided with a sheet placement section (stacking tray) for stacking plural formed booklets.
The booklets themselves are formed in the finishing apparatus main body, and the booklets successively discharged from an outlet of the finishing apparatus main body are successively stacked on the sheet placement section.
Although the sheet placement section is provided with a mechanism to stably stack many booklets without collapsing of a pile, an improvement of the mechanism is demanded so that more booklets can be more stably stacked.
In the accompanying drawings,
Embodiments of a sheet finishing apparatus and a sheet finishing method will be described with reference to the accompanying drawings.
A sheet finishing apparatus according to an embodiment includes a main body to fold a sheet bundle and to form a booklet, a base plate which is inclined downward and extends from a side wall of the main body and stacks plural booklets successively discharged from an outlet provided in the side wall, an upper arm which is provided above the base plate and substantially in parallel to a stacking surface of the base plate and a base end of which is rotatably supported at an upper part of the outlet of the side wall, a fore arm which extends from a front end of the upper arm to the stacking surface to be substantially perpendicular to the base plate and receives a leading edge of the booklet stacked on the base plate, and an alignment roller which is provided at the front end of the upper arm, presses an upper surface of the booklet stacked on the base plate and rotates in a direction of urging the booklet to the fore arm.
The image forming section 12 of the image forming apparatus 10 includes a photoconductive drum 1 at the center. A charging unit 2, an exposure unit 3, a developing unit 4, a transfer unit 5A, a charge removing unit 5B, a separating pawl 5C, and a cleaning unit 6 are respectively disposed around the photoconductive drum 1. Besides, a fixing unit 8 is provided downstream of the charge removing unit 5B. An image forming process is performed by these units substantially in the following procedure.
First, the charging unit 2 uniformly charges the surface of the photoconductive drum 1. On the other hand, a document read by the reading unit 11 is converted into image data, and is inputted to the exposure unit 3. The exposure unit 3 irradiates a laser beam corresponding to the level of the image data to the photoconductive drum 1, and forms an electrostatic latent image on the photoconductive drum 1. The electrostatic latent image is developed with toner supplied from the developing unit 4 and a toner image is formed on the photoconductive drum 1.
A sheet contained in a sheet containing section 7 (7A, 7B, 7C) passes through a sheet thickness detection section 90 through some conveyance rollers, and is conveyed to a transfer position (a gap between the photoconductive drum 1 and the transfer unit 5A). At the transfer position, the transfer unit 5A transfers the toner image to the sheet from the photoconductive drum 1. The charge removing unit 5B erases the charge on the surface of the sheet on which the toner image is transferred. The separating pawl 5C separates the sheet from the photoconductive drum 1. Thereafter, the sheet is conveyed by an intermediate conveyance section 5D, is heated and pressed by the fixing unit 8, and the toner image is fixed to the sheet. The sheet subjected to the fixing is discharged from a discharge section 5E and is outputted to the sheet finishing apparatus 20.
The cleaning unit 6 disposed downstream of the separating pawl 5C removes a developer remaining on the surface of the photoconductive drum 1, and prepares for next image formation.
The sheet finishing apparatus 20 includes a sheet folding apparatus 30 and a sheet placement section 40 in addition to a sorter section to sort sheets.
The sheet folding apparatus 30 performs a process (saddle stitching) in which the center of plural printed sheets discharged from the image forming section 12 is stitched with staples, and then, folding is performed to form a booklet. There is also a case where only folding is performed without saddle stitching with staples, and the folded sheet bundle is stacked on the sheet placement section 40.
The booklet subjected to saddle stitching and folding (or folding alone) by the sheet folding apparatus 30 is outputted to the sheet placement section 40, and the booklet (sheet bundle) is finally mounted here.
The sheet folding apparatus 30 receives the sheet discharged from the discharge section 5E of the image forming section 12 by an inlet roller pair 31 and delivers it to an intermediate roller pair 32. The intermediate roller pair 32 further delivers the sheet to an exit roller pair 33. The exit roller pair 33 sends the sheet to a standing tray 34 having an inclined placement surface. The leading edge of the sheet is directed to the upper part of the inclination of the standing tray 34.
A stacker 35 is provided below the standing tray 34, and receives the lower edge of the sheet which is switched back and falls from the upper part of the inclination of the standing tray 34.
A stapler (saddle stitch unit) 36 is disposed at the middle of the standing tray 34. When saddle stitching (stapling) is performed on the sheet bundle, the position of the stacker 35 is adjusted so that the position of the sheet bundle to be stapled (the center of the sheet bundle in the up-and-down direction) faces the stapler 36.
After the stapler 36 saddle stitches the sheet bundle, then, the stacker 35 descends until the position of the sheet bundle where a fold line is to be formed (the center of the sheet bundle in the up-and-down direction and the position where the staples are inserted) comes to the front of a fold blade 37.
When the position where the fold line is to be formed comes to the front of the fold blade 37, a leading edge 37a of the fold blade 37 pushes a surface which becomes an inner surface after the sheet bundle is folded.
A fold roller pair 38 is provided ahead of the fold blade 37 in the traveling direction. The sheet bundle pushed by the fold blade 37 is rolled into a nip of the fold roller pair 38, and the fold line is formed at the center of the sheet bundle. The fold blade 37 and the fold roller pair 38 constitute a fold unit.
The sheet bundle on which the fold line is formed by the fold roller pair 38 is conveyed to a fold reinforcing unit 50 provided at the downstream side thereof. The sheet bundle conveyed to the fold reinforcing unit 50 is temporarily stopped there.
The fold reinforcing unit 50 includes a fold reinforcing roller 51 (a pair of rollers including an upper roller 51a and a lower roller 51b). The reinforcing roller pair 51 moves in the direction (direction along the line of the fold line) perpendicular to the conveyance direction of the sheet bundle while applying pressure to the fold line, and reinforces the fold line.
The sheet bundle whose fold line is reinforced by the fold reinforcing unit 50 again starts to be conveyed, is pulled by a discharge roller pair 39a, 39b and is outputted to the sheet placement section 40. The sheet bundle subjected to the saddle stitching, that is, the booklet is placed on the sheet placement section 40.
The sheet placement section 40 includes a bed 903, a base plate 915, an upper arm 907 and a fore arm 908. A detachable and attachable guard 905 is provided at a leading edge of the base plate 915.
The base plate 915 is connected to an outer side wall 902 of the main body of the sheet finishing apparatus 20 through a spring 906, and is, together with the bed 903, inclined downward and extends from the side wall 902 of the main body. Plural booklets successively discharged from an outlet 901 provided in the side wall 902 are stacked on the base plate 915.
Abase end of the upper arm 907 is rotatably supported around a shaft 909 provided in a support 910 fixed to the side wall 902.
A shaft 914 is provided at the front end of the upper arm 907, and the upper end of the fore arm 908 is rotatably supported by the shaft 914.
The base plate 915 has a gentle hill at the center in the direction along the inclination, and a flapper 950 is provided in the vicinity of the top of the hill. Besides, a hollow is formed in an upper portion of the inclination of the flapper 950. The lower end of the fore arm 908 is hooked in this hollow, and the fore arm 908 is substantially perpendicular to the stacking surface of the base plate 915.
A booklet stacked on the base plate 915 moves downward along the bed 903 and the stacking surface of the base plate 915 by its own weight, and the leading edge of the booklet is received by the fore arm 908.
As described later, an alignment roller 800 is provided at the front end of the upper arm 907 (see
The upper arm 907 is provided above the base plate 915 and substantially in parallel to the stacking surface of the base plate 915, and the base end thereof is rotatably supported by the shaft 909 at the upper part of the outlet 901.
The fore arm 908 extends from the front end of the upper arm 907 to the stacking surface to be substantially perpendicular to the base plate 915, and can receive the leading edge of the booklet stacked on base plate 915.
The alignment roller 800 is provided coaxially with the shaft 914 at the front end of the upper arm 907. The alignment roller 800 presses the upper surface of the booklet stacked on the base plate 915, and rotates in an arrow A direction to urge the booklet to the fore arm 908. The upper arm 907 includes a cover 907a, and
A pulley 801 is fixed to the alignment roller 800 coaxially with the shaft 914. A drive gear 810 and an intermediate gear 802 are provided in the vicinity of the base end of the upper arm 907, and the gears 810 and 802 are engaged with each other.
A pulley 803 is coaxially fixed to the intermediate gear 802. A belt 804 is stretched between the pulley 803 and the pulley 801 of the alignment roller 800 through a tension roller 805.
As shown in
The discharge roller pair 39a, 39b (see also
The discharge roller 39a rotates in a direction of an arrow D by the rotation of the motor, and the discharge roller 39b (driven roller) rotates in an arrow E direction. By this rotation, the booklet formed in the main body of the sheet finishing apparatus 20 passes through the outlet 901 and is discharged to the sheet placement section 40.
Meanwhile, the rotation force of the motor is transmitted through the belt 812 to the drive gear 810, and the drive gear rotates in an arrow C direction. The rotation is transmitted to the intermediate gear 802, and the intermediate gear 802 rotates in an arrow B direction. The rotation of the intermediate gear 802 is further transmitted to the alignment roller 800 through the belt 804, and rotates the alignment roller 800 in the direction of the arrow A.
A booklet T discharged from the outlet 901 slides down on the bed 903 and the base plate 915 by its own weight, and the leading edge thereof is received by the fore arm 908 and is stopped.
The booklets successively discharged from the outlet 901 are stacked on the previously discharged booklet. When the number of booklets becomes large, depending on a type of a sheet of the booklet, there is a case where the center parts of the booklets are bent downward and a hollow is generated. There is a case where the booklet discharged later is stopped by this hollow before the leading edge of the booklet reaches the fore arm 908. Besides, the stop positions of the booklets discharged later can become irregular due to the friction between the booklets. That is, there can occur a case where the longitudinal alignment of the booklets becomes insufficient. There is a tendency that this phenomenon in which the longitudinal alignment is insufficient becomes remarkable as the number of booklets becomes large, that is, the height of the stacked booklet bundles approaches the upper arm 907.
In order to deal with the phenomenon as stated above, the alignment roller 800 which presses the upper surface of the booklet and rotates in the direction of urging the booklet to the fore arm 908 (the direction of an arrow F and the arrow A in
The upper surface of the booklet, especially the upper surface of the booklet positioned at the uppermost position when the number of booklets becomes large is urged in the direction toward the fore arm 908 by the rotation of the alignment roller 800. As a result, the leading edge of the booklet can be aligned at the position of the fore arm 908, and the longitudinal alignment can be improved.
Besides, in the rotation force transmission mechanism of the upper arm 907 of this embodiment, the intermediate gear 802 is provided between the drive gear 810 and the alignment roller 800. The rotation directions of the drive gear 810 and the intermediate gear 802 are respectively the arrow C direction and the arrow B direction in
As a result, the alignment roller 800 can convey the booklet in the direction toward the fore arm 908 while pressing the booklet from above, and the longitudinal alignment of the booklet bundle can be further improved.
So far, it has been explained that the leading edge of the booklet is received by the fore arm 908. Instead, it may be possible to configure the sheet placement section 40 without the fore arm 908. In this case, the leading edge of the booklet is received by, for example, the guard 905 located in a forward direction of the base plate 915, and the alignment roller 800 urges the booklet in a forward direction of the base plate 915, while pressing the booklet from above.
The conveyance assist roller 850 is coaxially fixed to, for example, the shaft of the intermediate gear 802 in the first embodiment. As a result, the conveyance assist roller 850 can be rotated in the arrow H direction without adding a specific drive mechanism to the upper arm 907 of the first embodiment.
According to the first embodiment, the leading edge of the booklet bundle is pressed to the fore arm 908 by the rotation of the alignment roller 800 and the pressing from above, and the longitudinal alignment is improved. However, if the leading edge of the booklet does not reach the position of the alignment roller 800 due to the friction between the booklets, this effect of the alignment roller 800 is not obtained.
According to the second embodiment, the conveyance assist roller 850 is further provided to the upper arm 907, so that the booklet discharged from an outlet 901 is pushed to the alignment roller 800 positioned at the front end of the upper arm 907, and the booklet can be certainly sent to the position where the leading edge of the booklet contacts the alignment roller 800. In other words, the booklet is delivered from discharge rollers 39a and 39b, and can be further delivered to the alignment roller 800. As a result, the longitudinal alignment improving effect of the alignment roller 800 can be. made more certain.
As described above, according to the sheet finishing apparatus 20 including the sheet placement section 40 of the first or the second embodiment and the sheet finishing method, the leading edges of the booklets stacked on the sheet placement section 40 are uniformed and can be excellently aligned.
As a result, after the user takes out the booklet bundles from the sheet placement section 40, the operation of again aligning the booklet bundles at a different place is unnecessary, or, if any, the operation load of alignment is much reduced.
Besides, since the booklets stacked on the sheet placement section 40 are uniformly stacked, so-called “a collapse of a pile” does not occur, and paper jam of the booklet discharged later can be prevented.
Further, since the longitudinal alignment is improved, and the occurrence of the collapse of a pile is prevented, the number of booklets stacked on the sheet placement section 40 can be further increased.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel apparatuses and units described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the apparatuses and units described herein may be made without departing from the spirit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
This application is based upon and claims the benefit of priority from: U.S. provisional applications 61/231191 filed on Aug. 4, 2009, and 61/318247 filed on Mar. 26, 2010, the entire contents of each of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61231191 | Aug 2009 | US | |
| 61318247 | Mar 2010 | US |
