The present invention relates to a sheet feeder, an image forming apparatus having the same and a method for sheet feeding, and particularly to a large capacity sheet feeder in which sheet bundles to be fed are horizontally arranged and can be stacked, an image forming apparatus having the same and a method for sheet feeding.
A certain image forming apparatus, such as a copier or an MFP (Multi-Function Peripheral), has a large capacity sheet feeder which can contain a large amount of sheets before printing. As one of such large capacity sheet feeders, there is a tandem large capacity feeder (hereinafter referred to as a tandem LCF).
The tandem LCF has two spaces in which sheet bundles can be horizontally arranged and contained. A sheet bundle stacking tray called a sheet feed tray is provided at a lower part of one of the spaces, and a sheet bundle stacking tray called a conveyance tray is provided at a lower part of the other space. A sheet bundle of, for example, about 1000 or more sheets can be stacked on each of the sheet feed tray and the sheet conveyance tray.
When a sheet is printed, the sheet is sequentially picked up one by one from the upper side of the sheet bundle stacked on the sheet feed tray. The picked up sheet is used for print processing through a conveyance path.
When a sensor detects that all sheets in the sheet bundle on the sheet feed tray are used, the conveyance tray on which a different sheet bundle is stacked is moved to the sheet feed tray side, and the conveyance tray is stopped at a position where the conveyance tray overlaps the sheet feed tray. Thereafter, the conveyance tray returns to the original position while leaving the sheet bundle stacked thereon on the sheet feed tray. As a result, the new sheet bundle is stacked on the sheet feed tray which became empty, and sheet feeding for a next print operation becomes possible.
Although the conveyance tray returned to the original position is empty, the conveyance tray is constructed to be capable of being pulled out to the outside independently of the sheet feed tray. Thus, even when sheets are being fed from the sheet feed conveyance tray.
It is desirable that ends of the sheet bundle stacked on the sheet feed tray are aligned in a longitudinal direction and a lateral direction (that is, alignment is performed in the longitudinal direction and the lateral direction). When printing is started in a state where the alignment is not performed in the longitudinal direction or the lateral direction, each sheet of the sheet bundle is picked up in such a state that the position of the sheet is shifted in the longitudinal direction or the lateral direction (or both directions), and there is a possibility that printing is performed at an unsuitable position.
In the tandem LCF of the related art, alignment in the movement direction of the conveyance tray (hereinafter, the movement direction of the conveyance tray is called a longitudinal direction, and the alignment in the longitudinal direction is called longitudinal alignment) can be relatively easily performed by pressing the sheet bundle to a side wall of the sheet feeder by the driving force of the conveyance tray.
However, alignment in a direction perpendicular to the movement direction of the conveyance tray (hereinafter, the direction perpendicular to the movement direction of the conveyance tray is called a lateral direction, and the alignment in the lateral direction is called lateral alignment) is insufficient.
The present invention is made in view of the above circumstances, and it is an object to provide a sheet feeder in which both longitudinal alignment and lateral alignment can be well performed in a tandem large capacity sheet feeder, an image forming apparatus having the same and a method for sheet feeding.
In order to achieve the object, according to an aspect of the invention, a sheet feeder includes a sheet feed tray on which a first sheet bundle is stacked at a first position where sheet feeding to a conveyance path can be performed, and a conveyance tray on which a second sheet bundle is stacked at a second position adjacent to the sheet feed tray, and which conveys the second sheet bundle to the sheet feed tray and stacks the second sheet bundle on the sheet feed tray after the first sheet bundle is fed, presses the stacked second sheet bundle to a side plate provided in a direction perpendicular to a conveyance direction of the conveyance tray, and aligns an end of the second sheet bundle.
According to another aspect of the invention, an image forming apparatus includes a scanner to read an original document and to generate image data, an image forming section to print the image data on a sheet, and a sheet feeder to feed the sheet to the image forming section, in which the sheet feeder includes a sheet feed tray on which a first sheet bundle is stacked at a first position where sheet feeding to a conveyance path can be performed, and a conveyance tray on which a second sheet bundle is stacked at a second position adjacent to the sheet feed tray, and which conveys the second sheet bundle to the sheet feed tray and stacks the second sheet bundle on the sheet feed tray after the first sheet bundle is fed, presses the stacked second sheet bundle to a side plate provided in a direction perpendicular to a conveyance direction of the conveyance tray, and aligns an end of the second sheet bundle.
According to still another aspect of the invention, a method of sheet feeding includes stacking a first sheet bundle on a sheet feed tray disposed at a first position to feed a sheet to a conveyance path, stacking a second sheet bundle on a conveyance tray at a second position adjacent to the sheet feed tray, conveying the second sheet bundle to the sheet feed tray and stacking it on the sheet feed tray after the first sheet bundle is fed, and pressing the stacked second sheet bundle to a side plate provided in a direction perpendicular to a conveyance direction of the conveyance tray to align an end of the second sheet bundle.
In the accompanying drawings,
An embodiment of an image forming apparatus and a method of sheet feeding of the invention will be described with reference to the accompanying drawings.
Besides, the image forming apparatus 1 includes an operation display section 50 to give an instruction of printing in the image forming section 10 and an instruction of document reading in the scanner 30. Further, a sheet tray 60 for discharging a sheet printed in the image forming section 10 and a foldable manual feed tray 70 are provided on the side of the image forming apparatus 1.
The tandem LCF 20 is constructed to be capable of being pulled out in the front direction in
The tandem LCF 20 includes a sheet containing section surrounded by front side plates 203 and 305, two side panels 102 and 103, and rear side plates 202 and 304. The sheet containing section can contain a first sheet bundle P1 and a second sheet bundle P2 arranged side by side.
The first sheet bundle P1 is stacked at the right position (first position) of the sheet containing section when viewed from the front side of a front panel 100, and the second sheet bundle P2 is stacked at the left position (second position) of the sheet containing section.
A sheet feed tray 101 on which the first sheet bundle P1 is stacked is provided at the first position and on the bottom side. The rear side plate (side plate) 304 is provided to extend upward at the rear of the sheet feed tray 101 when viewed from the front side of the front panel 100, and the front side plate (second side plate) 305 is provided to extend upward in front of the sheet feed tray 101.
On the other hand, a conveyance tray 201 on which a second sheet bundle P2 is stacked is provided at the second position and on the bottom side. The rear side plate (side plate) 202 is provided to extend upward at the rear of the conveyance tray 201 when viewed from the front side of the front panel 100, and the front side plate (second side plate) 203 is provided to extend upward in front of the conveyance tray 101.
Further, a sheet rear end guide 200 is provided to extend upward at the left of the conveyance tray 201 when viewed from the front side of the front panel 100.
Besides, thin and long stoppers 302 and 303 extending in the up-and-down direction are respectively provided at a front position and a rear position between the sheet feed tray 101 and the conveyance tray 201.
An arrow A indicates a conveyance direction of the second sheet bundle P2 by the conveyance tray 201. As stated above, the first sheet bundle P1 is stacked on the sheet feed tray 101, and the second sheet bundle P2 is stacked on the conveyance tray 201.
A sheet is fed to the image forming section 10 from the first sheet bundle P1 stacked on the sheet feed tray 101. When all sheets in the first sheet bundle P1 on the sheet feed tray 101 are fed, the conveyance tray 201 on which the second sheet bundle P2 is stacked is moved in the arrow A direction from the second position, overlaps the sheet feed tray 101 at the first position and is stopped. At this time, the sheet rear end guide 200, together with the conveyance tray 201, is moved in the arrow a direction, and presses the end of the second sheet bundle P2 in the conveyance direction (that is, the longitudinal direction) to the side panel 103 (see
Thereafter, the conveyance tray 201 moves in a direction opposite to the arrow A while leaving the second sheet bundle P2 on the sheet feed tray 101, and returns to the second position in an empty state.
An arrow B to an arrow G indicate movements relating to lateral alignment of the second sheet bundle P2. The lateral alignment may be performed when the conveyance tray 201 is at the second position, or may be performed at the position (first position) where it overlaps the sheet feed tray 101.
When the lateral alignment is performed while the conveyance tray 201 is at the second position, the conveyance tray 201 moves the second sheet bundle P2 in the direction perpendicular to the conveyance direction (that is, in the lateral direction). For example, the second sheet bundle P2 is moved in an arrow C direction, and the end of the second sheet bundle P2 in the lateral direction is pressed to the rear side plate 202. Further, the front side plate 203 may be moved in an arrow E direction to press the end of the second sheet bundle P2 at the opposite side in the lateral direction. By these pressing operations, the lateral alignment of the second sheet bundle P2 is performed. Thereafter, the conveyance tray 201 and the front side plate 203 move in an arrow B direction and an arrow D direction and return to the original positions.
On the other hand, when the conveyance tray 201 performs the lateral alignment at the first position, after the conveyance tray 201 moves to the first position (that is, after the conveyance tray 201 overlaps the sheet feed tray 101), the second sheet bundle P2 is moved in the arrow C direction, and the end of the second sheet bundle P2 in the lateral direction is pressed to the rear side plate 304. Further, the front side plate 305 may be moved in an arrow G direction to press the end of the second sheet bundle P2 at the opposite side in the lateral direction. Also by these pressing operations, the lateral alignment of the second sheet bundle P2 is performed. Thereafter, the conveyance tray 201 moves in the arrow B direction and returns to the original position, and similarly, the front side plate 305 moves in an arrow F direction and returns to the original position.
In
Perspective views and plan views shown in
As shown in
Besides, as shown in
When the tandem LCF 20 is pushed into the image forming apparatus 1, as shown in
Besides, the conveyance tray 201 and the front side plate 203 move the second sheet bundle P2 in an arrow direction of
Immediately after a user stacks the second sheet bundle P2 on the conveyance tray 201, the ends of the second sheet bundle P2 are not laterally aligned and are often irregular.
Then, when a not-shown sensor detects that the tandem LCF 20 in which the second sheet bundle P2 is stacked on the conveyance tray 201 is pushed into the image forming apparatus 1, the conveyance tray 201 moves in the arrow C direction, and presses the end of the second sheet bundle P2 in the lateral direction to the rear side plate 202 to perform the lateral alignment, as shown in
Further, as shown in
Thereafter, as shown in
Meanwhile, sheets are sequentially fed from the first sheet bundle P1 stacked on the sheet feed tray 101 to the image forming section 10 by a pickup roller 300 (see
When a not-shown sensor detects that the sheet feed tray 101 becomes empty, the stoppers 302 and 303 are moved to open positions, and a path in which the second sheet bundle P2 moves to the first position is secured, as shown in
Thereafter, as shown in
When the conveyance tray 201 moves to a position (first position) where it completely overlaps the sheet feed tray 101, the sheet rear end guide 200 presses the end of the second sheet bundle P2 in the longitudinal direction to the side panel 103, and the longitudinal alignment is performed.
As described above, although the lateral alignment of the second sheet bundle P2 may be performed when the conveyance tray 201 is at the second position, it may be performed after the conveyance tray 201 is moved to the first position. Arrows shown in
When the longitudinal alignment and the lateral alignment are ended at the first position, the stoppers 302 and 303 are moved to the closed positions, as shown in
For the case in which the lateral alignment is performed at the second position, only the longitudinal alignment is performed at the first position, and accordingly, immediately after the longitudinal alignment is ended, the stoppers 302 and 303 are moved to the closed positions.
Thereafter, as shown in
Finally, as shown in
While the second sheet bundle P2 left on the sheet feed tray 101 is placed in a state where sheet feeding can be performed by the pickup roller 300 (see
As described above, according to the tandem LCF 20 (sheet feeder) of the embodiment, the image forming apparatus 1 having the same and the method for sheet feeding, both the longitudinal alignment and the lateral alignment of the stacked sheet bundle can be well performed, and a large amount of sheets can be continuously fed.
The invention is not limited to the above embodiment, and at the practical stage, the components can be modified and embodied within the scope not departing from the gist. Besides, various embodiments of the invention can be formed by suitable combinations of the plural components disclosed in the embodiment. For example, some components may be deleted from all components described in the embodiment. Further, components of different embodiments may be suitably combined.
This application is based upon and claims the benefit of priority from U.S. provisional application 61/012,768, filed on Dec. 10, 2007, and the entire contents of each of which are incorporated herein by reference.
Number | Date | Country | |
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61012768 | Dec 2007 | US |