Inkjet Printer Paper Transport Curling Control

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Solution Overview

Problem

Inkjet printers face challenges in smoothly transporting paper sheets due to curling issues during inversive transport, especially at the paper sheet end, which can cause paper jams and affect print quality.

Innovation Solution

A printing apparatus with a rotation control unit that manages the paper sheet transport roller to perform a decurling process by pinching the paper sheet at specific positions based on the amount of ejected ink and humidity, ensuring the distance from the pinch position to the paper sheet end is controlled to prevent curling and rubbing against the ejection head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the paper sheet is transported by the inverting portion during inversive transport, then the paper sheet can be inverted for double-sided printing, but curling is caused at the end of the paper sheet which is the free end, making it difficult to transport smoothly

Engineering Contradiction:

Improvedouble-sided printing capabilityVSAvoidtransport smoothness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The pinch portion applies a preliminary counteracting force to the curling tendency at the paper sheet end during inversive transport. By pinching the paper sheet at a position that creates a moment opposite to the curling direction, the system prevents the free end from contacting the ejection head before printing occurs, thereby maintaining transport reliability while enabling double-sided printing

Inventive Principle:

Principle #9Preliminary anti-action

2Device complexity

If the paper sheet end is a free end cantilevered with the pinch position, then the inversive transport can be simplified, but it is difficult to suppress curling at the end of the paper sheet

Engineering Contradiction:

Improveinverting mechanism complexityVSAvoidcurling suppression accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The pinch portion performs a preliminary action by applying a counter-curving moment to the paper sheet during inversive transport, preparing the paper sheet end to resist curling before it reaches the ejection head. This preliminary intervention ensures that even with a simplified cantilevered transport mechanism, the paper sheet maintains sufficient flatness for high-precision printing

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If the paper sheet is pinched in a predetermined position to suppress curling, then curling in that region can be reduced, but the downstream end remains a free end that is difficult to control

Engineering Contradiction:

Improvecurling control at pinch positionVSAvoidtransport control difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The pinch portion acts as a counterbalancing mechanism that applies a moment opposite to the curling tendency at the paper sheet end. By positioning the pinch portion to create a counter-moment, the system balances the curling forces without requiring complex active control of the free end, thereby maintaining ease of operation while improving curling suppression

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Data Source

PatentUS10189287B2Printing apparatus

Publication Date: 2019.01.29 SEIKO EPSON CORP

AI summary

Provided is a printing apparatus capable of smoothly transporting a paper sheet, on a first surface of which printing is performed, with the paper sheet facing an ejection head.