Printing Apparatus Rear-End Cutting Mark Placement

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Solution Overview

Problem

Existing printing apparatuses struggle to accurately cut continuous sheets into cut sheets when the conveyance direction during printing is opposite to the conveyance direction during cutting, leading to undetected cutting positions and increased sheet consumption due to the need for dummy pages.

Innovation Solution

A printing apparatus that prints cutting marks on the rear end portions of pages instead of the front end portions, allowing for reliable detection of cutting positions even when conveyance directions differ, while minimizing sheet consumption by optimizing cutting mark placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cutting marks are printed at the front end portion of pages, then cutting positions can be detected when conveyance directions are the same, but cutting positions cannot be detected when conveyance directions are opposite

Engineering Contradiction:
Improvedetection reliability of cutting markVSAvoidadaptability to different conveyance directions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional approach by printing cutting marks at the rear end portion of pages instead of the front end portion. This inversion allows the cutting mark to be detected at the front end of the page during cutting operation, regardless of whether the conveyance direction during printing is the same or opposite to the conveyance direction during cutting. The rear end portion printing position ensures that the cutting mark passes through the photosensor measurement path at the front end during cutting, solving the detection problem for opposite conveyance directions.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If dummy pages are added to enable cutting when conveyance directions are opposite, then cutting can be performed, but sheet consumption increases

Engineering Contradiction:
Improvecutting capabilityVSAvoidsheet consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

By inverting the cutting mark printing position to the rear end portion of pages, the patent eliminates the need for dummy pages when conveyance directions are opposite. The cutting mark printed at the rear end portion naturally positions itself for detection at the front end during cutting, enabling direct cutting without requiring additional dummy pages, thus reducing sheet consumption.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The rear end portion printing position serves multiple functions: it enables cutting mark detection for both same-direction and opposite-direction conveyance scenarios, and eliminates the need for separate dummy pages. This universal solution works regardless of the conveyance direction relationship between printing and cutting operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of substance

If cutting marks are printed at the front end portion, then sheet consumption is minimized, but cutting accuracy deteriorates when conveyance directions are opposite

Engineering Contradiction:
Improvesheet consumptionVSAvoidcutting position accuracy
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent inverts the printing position to the rear end portion, which simultaneously achieves accurate cutting positioning and minimizes sheet consumption. By printing at the rear end portion, the cutting mark is properly positioned for detection during cutting without requiring dummy pages, thus achieving both cutting accuracy and sheet efficiency in one solution.

Inventive Principle:
Principle #13The other way round (Inversion)

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

Enables accurate cutting of continuous sheets into cut sheets at desired positions, even with opposite conveyance directions, while reducing sheet waste and ensuring reliable detection of cutting marks.

Implementation Method 1

The printing apparatus detects the cutting mark CMD1 (CMD2) based on an output signal SGD1 of a photo sensor or the like facing the movement path of the cutting mark

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4059728B1Printing apparatus and printing method
Publication Date: 2025.01.22 SCREEN HOLDINGS CO LTD
  • EP4059728B1 patent drawingFigure 1
  • EP4059728B1 patent drawingFigure 2
  • EP4059728B1 patent drawingFigure 3~4

AI summary

An object of the present invention is to form a cutting mark that allows cutting a continuous sheet into a cut sheet on the continuous sheet while suppressing the consumption of the continuous sheet and can cut the continuous sheet into a cut sheet at a desired position. In order to achieve the object, a printing apparatus configured to print on a continuous sheet to be cut into a plurality of cut sheets at a plurality of cutting positions arranged in a longitudinal direction while being conveyed in the longitudinal direction, includes a conveyance mechanism configured to convey the continuous sheet in the longitudinal direction, and a print head provided so as to face a conveyance path for the continuous sheet in the conveyance mechanism and configured to sequentially print a plurality of cutting marks indicating the plurality of cutting positions on the continuous sheet being conveyed by the conveyance mechanism, in which, from between front end portions and rear end portions of each of the pages in a conveyance direction of the continuous sheet in the conveyance mechanism when printing by the print head is performed, the print head prints the cutting marks on the rear end portions for a plurality of pages on the continuous sheet corresponding to the plurality of cut sheets, and the print head performs printing such that a dimension, in the longitudinal direction, of the cutting marks to be printed on the rear end portions is printing on the rear end portions from between the front end portions and the rear end portions of the pages.