Sheet Alignment Mechanism for Jam Suppression in Post-Processing

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Solution Overview

Problem

Existing post-processing apparatuses face challenges in suppressing jams and maintaining alignment accuracy when using rotating members like paddles or belts to align sheets, as the conveyance force required for proper alignment is difficult to manage, leading to either misalignment or buckling issues.

Innovation Solution

A post-processing apparatus with a buffer unit that temporarily holds sheets, a stacking unit for alignment, and a control unit that determines the number of sheets based on physical parameters affecting frictional force, ensuring optimal conveyance force for accurate alignment and preventing jams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotating member (paddle or belt) is used to convey sheets for alignment, then sheet alignment can be performed, but alignment accuracy deteriorates due to sheet buckling when conveyance force is too strong

Engineering Contradiction:

Improvealignment operationVSAvoidalignment accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The sheet conveyance and alignment process is divided into two separate stages: first, the buffer mechanism conveys multiple sheets to the alignment unit; second, a separate pressing mechanism applies pressure to press the sheets against the end regulating member for precise alignment. This segmentation allows each mechanism to be optimized independently, preventing buckling while achieving accurate alignment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A pressing mechanism is introduced as an intermediary between the rotating member and the end regulating member. This pressing mechanism applies controlled pressure to the sheets during alignment, preventing buckling caused by excessive conveyance force while ensuring the sheets are properly positioned against the regulating member for accurate alignment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If conveyance force from rotating member is increased to prevent sheet alignment failure, then sheets can reach end regulating member, but sheet buckling occurs between rotating member and end regulating member

Engineering Contradiction:

Improvealignment reliabilityVSAvoidsheet buckling

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the physical state of sheet conveyance by introducing a pressing force parameter. The pressing mechanism applies a controlled pressure parameter that counteracts the excessive conveyance force, transforming the harmful high-force contact into a controlled pressing action that prevents buckling while maintaining alignment reliability.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If multiple sheets are conveyed as a sheet stack for alignment, then productivity increases, but alignment accuracy and jam suppression become more difficult to maintain

Engineering Contradiction:

Improvesheet processing throughputVSAvoidalignment accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The alignment process is segmented into two independent functions: the buffer mechanism handles multiple sheets for productivity, while the pressing mechanism ensures precise alignment by pressing the sheet stack against the end regulating member. This segmentation allows multiple sheets to be processed simultaneously without compromising alignment accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pressing mechanism serves as an intermediary that acts on the entire sheet stack uniformly. By applying pressure across all sheets in the stack, it ensures that each sheet is properly positioned against the end regulating member, maintaining alignment accuracy even when processing multiple sheets together, thus enabling high productivity without sacrificing precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively maintains alignment accuracy and suppresses jams by adjusting the number of sheets conveyed based on frictional force parameters, ensuring proper alignment and preventing buckling or misalignment during the sheet alignment process.

Implementation Method 1

the control unit determines the predetermined number of sheets based on one or more physical parameters that affect a frictional force generated on the surface of the sheet

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS12252371B2Post-processing apparatus that performs post-processing on sheets discharged from image forming apparatus

Publication Date: 2025.03.18 CANON KK

AI summary

A buffer unit receives a sheet and temporarily holds a predetermined number of sheets so as to be overlaid on one another. A stacking unit stacks the predetermined number of sheets conveyed toward a first direction. A moving unit comes into contact with an uppermost sheet among the predetermined number of sheets stacked on the stacking unit and moves the uppermost sheet further toward the first direction. A regulating unit comes into contact with an end portion of the stack of sheets on the stacking unit to regulate the position of the stack of sheets. A control unit controls the predetermined number of sheets.