Sheet Stacking Shift Unit for Image Forming Apparatus

Solution Overview

Problem

In inside discharging type image forming apparatuses, the visual recognition and ease of removal of discharged sheets are compromised due to the shifting and alignment issues caused by varying sheet sizes, where smaller sheets are covered by larger ones, making it difficult for users to identify and remove them without disrupting the alignment.

Innovation Solution

A sheet stacking apparatus with a shift unit and controller that aligns sheets of different lengths at specific positions in the sheet width direction, ensuring shorter sheets are positioned closer to the take-out port, improving visual recognition and ease of removal by preventing overlap and maintaining alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If sheets are shifted and discharged using a reference line on the proximal side as a reference regardless of sheet size, then the discharge process is simplified, but smaller sheets are covered by larger sheets making visual recognition and removal difficult

Engineering Contradiction:

Improvedischarge process complexityVSAvoidvisual recognition and removal of sheets

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent applies local quality by differentiating the stacking position based on sheet size. Short sheets are stacked at a first position (shifted toward the distal end), while long sheets are stacked at a second position (aligned with the proximal end). This localized differentiation ensures that short sheets remain visible and accessible without requiring complex discharge mechanisms.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-positioning sheets according to their size before discharge. The stacking apparatus automatically determines sheet length and places each sheet at the appropriate position (first position for short sheets, second position for long sheets) in advance, preventing coverage issues before they occur rather than requiring post-discharge adjustments.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If sheets are stacked at a fixed position regardless of size, then stacking is simplified, but alignment is lost when sheets of different sizes are stacked

Engineering Contradiction:

Improvestacking mechanism complexityVSAvoidsheet alignment precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by differentiating the stacking position based on sheet size. Short sheets are stacked at a first position (shifted toward the distal end), while long sheets are stacked at a second position (aligned with the proximal end). This localized differentiation ensures that short sheets remain visible and accessible without requiring complex discharge mechanisms.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the stacking position variable rather than fixed. The stacking apparatus dynamically adjusts the stacking position based on sheet length detection, selecting between a first position for short sheets and a second position for long sheets. This dynamic adjustment maintains alignment precision without requiring complex real-time adjustment mechanisms during discharge.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If short sheets are stacked at the same position as long sheets, then the stacking process is simpler, but short sheets are covered and become difficult to identify

Engineering Contradiction:

Improvestacking process complexityVSAvoidvisibility of short sheets

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent applies local quality by differentiating the stacking position based on sheet size. Short sheets are stacked at a first position (shifted toward the distal end), while long sheets are stacked at a second position (aligned with the proximal end). This localized differentiation ensures that short sheets remain visible and accessible without requiring complex discharge mechanisms.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-positioning sheets according to their size before discharge. The stacking apparatus automatically determines sheet length and places each sheet at the appropriate position (first position for short sheets, second position for long sheets) in advance, preventing coverage issues before they occur rather than requiring post-discharge adjustments.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9216873B2Sheet stacking apparatus and sheet processing apparatus as well as image forming apparatus

Publication Date: 2015.12.22 CANON KK

AI summary

Disclosed is a sheet processing apparatus including an intermediate processing tray on which a sheet conveyed by a discharge roller is stacked, a proximal aligning plate and a distal aligning plate moving in a sheet width direction for aligning the sheet conveyed onto the intermediate processing tray, and a finisher controller for moving and controlling the proximal aligning plate and the distal aligning plate to align, when a sheet having a length in the sheet conveyance direction shorter than a predetermined length in the sheet conveyance direction is conveyed, the sheet at a position shifted nearer to a take-out port side A in the sheet width direction than a position in the sheet width direction at which a sheet having a length in the sheet conveyance direction equal to or more than the predetermined length in the sheet conveyance direction is aligned.