Sheet Buffer Apparatus Mixed Sheet Handling

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Solution Overview

Problem

Conventional post-processing apparatuses experience decreased productivity when handling mixed sheets due to canceled buffering operations, which affects the overall image forming apparatus productivity, especially in high-demand print jobs requiring various sheet types.

Innovation Solution

A post-processing apparatus that determines whether to buffer sheets based on the capability of both the current and succeeding sheets, preventing cancellation of buffering processing and maintaining optimal sheet intervals to enhance productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If buffering is performed for all sheets to maintain productivity, then overall processing efficiency is improved, but sheets requiring special handling (index paper, thick paper, thin paper) may be damaged or cause jams

Engineering Contradiction:
Improveimage forming apparatus productivityVSAvoidsheet damage (scratch, wrinkle, jam)
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating buffering treatment based on sheet type. The determination unit identifies specific sheets requiring special handling (index paper, thick paper, thin paper) and applies different buffering strategies: normal buffering for regular sheets, and inhibited buffering for special sheets. This localized approach allows productivity maintenance for most sheets while protecting vulnerable sheets from damage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by determining sheet types and deciding buffering strategy in advance, before the buffering operation occurs. The determination unit identifies special sheets ahead of time, and the control unit pre-configures the buffering inhibition, preventing potential damage before it can occur while maintaining smooth processing for regular sheets.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If buffering is inhibited for special sheets to prevent damage, then sheet quality is protected, but productivity decreases due to wider sheet intervals and canceled buffering operations

Engineering Contradiction:
Improvesheet damage preventionVSAvoidpost-processing apparatus productivity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating buffering treatment based on sheet type. The determination unit identifies specific sheets requiring special handling (index paper, thick paper, thin paper) and applies different buffering strategies: normal buffering for regular sheets, and inhibited buffering for special sheets. This localized approach allows productivity maintenance for most sheets while protecting vulnerable sheets from damage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses copying by creating a virtual model of sheet properties through the determination unit, which identifies sheet types without physically examining each sheet. This information copying allows the control system to make informed buffering decisions based on sheet characteristics, balancing protection needs with productivity requirements.

Inventive Principle:
Principle #26Copying

3Stability of the object's composition

If buffering is performed by take-up method, then sheets are retained effectively during post-processing, but the take-up roller must stop and wait, increasing processing time

Engineering Contradiction:
Improvesheet retention stabilityVSAvoidprocessing time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent implements preliminary action by performing buffering operations in advance before post-processing begins. Sheets are overlaid and retained on the processing tray beforehand, so that during post-processing the sheets are already in position and do not require the take-up roller to stop and wait. This eliminates idle time while maintaining stable sheet retention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies continuity of useful action by ensuring that buffering operations complete before post-processing starts, allowing the post-processing apparatus to operate continuously without interruption. The sheet retention is established in advance, maintaining continuous productive operation without the take-up roller needing to pause during critical post-processing steps.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP2397911B1Sheet buffer apparatus, post-processing apparatus, control method, and image forming apparatus
Publication Date: 2015.02.25 CANON KK
  • EP2397911B1 patent drawingFigure 1
  • EP2397911B1 patent drawingFigure 2
  • EP2397911B1 patent drawingFigure 3

AI summary

A sheet buffer apparatus (505, 511, 522) which retains a sheet to be conveyed to a post-processing means (500) for performing post-processing for a sheet, the apparatus comprises a buffer means (505) for performing buffer processing to retain a sheet to be conveyed to the post-processing means (500) and overlay the sheet to be retained and a succeeding sheet; a determination means (952) for determining whether a sheet is inhibited from the buffer processing by the buffer means (505); and a control means (952) for, when the determination means (952) determines that the sheet succeeding the sheet to be retained is a sheet for which the buffer processing is inhibited, controlling the buffer means (505) not to perform the retaining of the sheet to be retained.