Printing Apparatus Skew Correction Overlap Control

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Solution Overview

Problem

Existing printing apparatuses require confirmation of the marginal amounts of the trailing edge of a preceding sheet and the leading edge of a succeeding sheet before starting to feed the succeeding sheet, leading to delays in the printing process.

Innovation Solution

A printing apparatus and control method that allow the feeding of a succeeding sheet to begin even if the marginal amounts of the trailing edge of a preceding sheet and the leading edge of the succeeding sheet are not confirmed, by implementing a mechanism where the leading edge of the succeeding sheet overlaps the trailing edge of the preceding sheet, enabling continuous feeding without the need for explicit confirmation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the apparatus waits to confirm 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, then the sheet positioning accuracy is improved, but the printing process speed deteriorates

Engineering Contradiction:
Improvesheet positioning accuracyVSAvoidprinting process speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The apparatus performs preliminary skew correction on the succeeding sheet while it is still overlapping with the preceding sheet, before the trailing edge of the preceding sheet reaches the sheet separation position. This allows the succeeding sheet to be pre-positioned and corrected in advance, eliminating the need to wait for marginal amount confirmation before feeding, thus resolving the contradiction between positioning accuracy and process speed

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the apparatus starts to feed the succeeding sheet immediately without confirming marginal amounts, then the printing process speed is improved, but the sheet positioning accuracy deteriorates

Engineering Contradiction:
Improveprinting process speedVSAvoidsheet positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system performs skew correction and positioning of the succeeding sheet in advance while it is still in the overlap region with the preceding sheet, before the feeding decision is made. This preliminary action ensures that when feeding starts immediately, the sheet is already properly positioned and corrected, maintaining accuracy while enabling immediate feeding

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the apparatus performs skew correction only after the trailing edge of the preceding sheet passes the sheet separation position, then the device operation simplicity is maintained, but the printing process time increases

Engineering Contradiction:
Improvedevice operation simplicityVSAvoidprinting process time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The apparatus performs skew correction on the succeeding sheet in advance, while it is still overlapping with the preceding sheet and before the trailing edge of the preceding sheet reaches the sheet separation position. This preliminary correction eliminates the need for a separate post-feeding correction step, reducing total process time while maintaining operational simplicity through automated timing control

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3257680B1Printing apparatus and control method therefor
Publication Date: 2022.06.29 CANON KK
  • EP3257680B1 patent drawingFigure 1
  • EP3257680B1 patent drawingFigure 2
  • EP3257680B1 patent drawingFigure 3

AI summary

A printing apparatus comprises a first roller (3) configured to feed a sheet (2), a second roller (5) for conveying the sheet fed by the first roller, a print head (7) configured to print an image on the sheet conveyed by the second roller, and a carriage (10) configured to mount the print head and move in an intersecting direction which intersects a sheet conveyance direction. The control unit is configured to perform a skew correction operation for causing a leading edge of a succeeding sheet (1-B) to abut against the second roller when the second roller stops. The control unit performs the skew correction operation before a trailing edge of the preceding sheet (1-A) passes the second roller.