Sheet stacking apparatus and bookmaking apparatus using the same

Abstract

A sheet stacking apparatus includes a tray for sequentially stacking sheets from a discharge path. The tray including a fixed support member, a movable support member, and a drive device disposed on the moveable support member. The drive device moves the movable support member to allow the movable support device to support different sheet position according to a length of the sheet in a conveyance direction.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This invention is related to Japanese Patent Application No. 2005-175642 filed on Jun. 15, 2005 and hereby incorporated by reference in its entirety. BACKGROUND OF THE INVENTION [0002] The present invention relates to a sheet stacking apparatus in a bookmaking system that aligns, in proper page order, sheets bundled on a tray belonging to a finishing device of an image forming apparatus, such as a printer, printing machine or copier. The sheet bundle is bound to create a booklet, and a bookmaking apparatus is operable to mount a cover to a sheet bundle collected at the sheet stacking apparatus. [0003] Sheet stacking apparatus are widely used as a terminal device of an image forming apparatus such as a printer or printing machine, to stack sheets formed with images in page order. After aligning the sheets into a booklet, a bookmaking system applies adhesive to one edge of the stacked booklet and binds that to a cover sheet. Systems are k...

AI Technical Summary

Benefits of technology

[0021] With this configuration, sheets stacked on the tray can be formed to the optimum posture by the movable support member that moves according to the size of the sheet, enabling accurate alignment at a predetermined position.

[0039] The present invention configures tray means for stacking sheets from a discharge path and comprises a fixed support member that supports an edge of sheets, and a movable support member that supports the other edge of sheets and moves along a conveyance direction. The invention is equipped with drive means on the movable support member, that move to support varying positions of sheets according to the length of the sheet in the conveyance direction, so it is always possible to support the sheet stacked on the tray in any predetermined shape regardless of the size of the sheet. Therefore, it is possible to accurately position the sheet on the position controlling means that is in a right-angle position to the sheet conveyance direction.

[0040] Furthermore, the present invention provides a sheet stacking tray that is compact and lightweight, does not allow stacked sheets to be misaligned or disorganized, and does not allow sheets to be scattered outside of the apparatus, even if the tray that stacks sheets is compact and allows sheet edges to hang outside of the tray.

Problems solved by technology

However, if the sheet is thin, or curled, and the sheet sides are engaged to align the sheet width, the sheet can sometimes bounce or move upward or a curl can form ridges along the center line of the direction of discharge making it impossible to correctly align the width of sheets at the right position.

For example, a large-sized sheet will become misaligned toward a bent rear side, and may not reach the controlling position on the tray.

It is difficult, therefore, to correctly position sheets having different lengths in a conveyance direction at a reference position in the conveyance direction, and at a reference position in a direction orthogonal to the conveyance direction.

Trying to bend and align a sheet at this portion can cause large-sized sheets to be misaligned at the leading side of this uplifted portion.

This makes it difficult to position the front and back of the direction of sheet conveyance at the correct controlling position.

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