Duplex Printing Non-Image Area Sizing for Cut Mark Detection

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Solution Overview

Problem

In duplex printing, existing methods fail to accurately detect cut marks on continuous sheets due to conveyance errors, leading to incorrect cutting positions, especially when adjusting non-image area sizes based on subsequent images rather than preceding ones, which affects both mark detection reliability and sheet consumption.

Innovation Solution

The solution involves setting the length of non-image areas on both surfaces of a continuous sheet based on the length of the image printed preceding the non-image area on the second surface, ensuring accurate cut mark detection and reduction in sheet consumption by aligning the non-image area size with the conveyance direction and image size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the size of non-image area is adjusted based on precedent image size, then cut mark detection reliability is improved, but duplex printing function cannot be fulfilled

Engineering Contradiction:

Improvecut mark detection reliabilityVSAvoidduplex printing function

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of adjusting non-image area size based on the precedent image (front surface) as in prior art, this invention inverts the approach by adjusting based on the subsequent image (back surface). Specifically, when the back surface image size differs from the front surface image size, the non-image area is recalculated based on the back surface image dimensions, ensuring accurate cut mark detection during back surface printing while maintaining duplex printing functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If non-image area size is increased to accommodate conveyance error, then cutting position accuracy is improved, but sheet consumption increases

Engineering Contradiction:

Improvecutting position accuracyVSAvoidsheet consumption

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The non-image area size is made dynamic rather than fixed. It is adjusted based on the actual size of the subsequent image on the back surface. When the back surface image size varies, the non-image area is recalculated to provide just enough space for conveyance error compensation, avoiding excessive sheet consumption while maintaining cutting accuracy.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of non-image area size based on image dimensions. By calculating the non-image area as the difference between the back surface image size and front surface image size, the system adapts the parameter to match actual conveyance requirements, reducing waste while ensuring accurate cutting positions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9278555B2Printing apparatus and printing method

Publication Date: 2016.03.08 CANON KK

AI summary

In the case of performing duplex printing on a continuous sheet, by setting a length of a non-image area to an optimum length, both of mark detection having high reliability and the suppression of a sheet consumption amount are achieved. For this purpose, when duplex printing of a plurality of images on front and back surfaces of the continuous sheet is performed, on the basis of a length of the image to be printed precedently to a non-image area W3 on the second surface, the length of the non-image area common to the front and back surface is set.