Duplex Printing Sheet Feeding Control

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Solution Overview

Problem

Existing printing apparatuses face inefficiencies when printing on both sides of a sheet, as they require confirmation of the marginal amounts of the trailing edge of the preceding sheet and the leading edge of the succeeding sheet before starting to feed the succeeding sheet, leading to delays and unclear feeding mechanisms.

Innovation Solution

A printing apparatus that allows the feeding of a succeeding sheet without confirming the marginal amounts of the trailing edge of the preceding sheet and the leading edge of the succeeding sheet, utilizing a control method and system to synchronize the feeding and conveyance rollers, enabling overlap continuous feeding and reducing the time between printing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the marginal amounts of the trailing edge of the preceding sheet and the leading edge of the succeeding sheet are confirmed before starting to feed the succeeding sheet, then the printing precision is improved, but the feeding time is increased

Engineering Contradiction:
Improveprinting precisionVSAvoidfeeding time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-calculating the required marginal amounts and determining the timing for feeding the succeeding sheet in advance, based on the printing speed and sheet conveyance characteristics, so that the feeding operation can start without waiting for actual marginal amount confirmation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the printing operation status, sheet detection signals, and conveyance roller position information to dynamically adjust the feeding timing and ensure that the marginal amounts are satisfied while minimizing feeding delays

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the feeding of the succeeding sheet is delayed until marginal amounts are confirmed, then the printing quality is improved, but the printing productivity is reduced

Engineering Contradiction:
Improveprinting qualityVSAvoidprinting productivity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The control system performs preliminary calculations of the required marginal amounts and determines the optimal feeding start time in advance, allowing the feeding operation to proceed without delaying the printing productivity while ensuring printing quality requirements are met

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous useful action by overlapping the feeding operation of the succeeding sheet with the printing operation of the preceding sheet, so that the feeding process occurs during the printing time rather than adding to it, thereby maintaining high printing productivity

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If the distance between the preceding sheet and the succeeding sheet is narrowed, then the printing efficiency is improved, but the risk of sheet interference is increased

Engineering Contradiction:
Improveprinting efficiencyVSAvoidsheet interference risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically changes the parameter of sheet distance by adjusting the feeding timing and speed based on real-time detection of sheet positions and printing progress, allowing the distance to be minimized for efficiency while maintaining sufficient separation to prevent interference through precise control

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3147131B1Printing apparatus, control method therefor, program and storage medium
Publication Date: 2020.04.01 CANON KK
  • EP3147131B1 patent drawingFigure 1
  • EP3147131B1 patent drawingFigure 2
  • EP3147131B1 patent drawingFigure 3

AI summary

A printing apparatus includes a feeding roller configured to feed a sheet, a conveyance roller configured to convey the sheet fed by the feeding roller, a printhead configured to print the sheet conveyed by the conveyance roller, and a control unit configured to, when performing a printing operation on both sides of the sheet, start to feed a succeeding sheet before the printing operation on a back surface of a preceding sheet is complete, and maintain a distance between a trailing edge of the preceding sheet and a leading edge of the succeeding sheet at an almost constant distance after feeding of the succeeding sheet starts.