Intermediate Unit Skew Correction for Printing Apparatus

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In printing systems, the swelling of paper sheets due to aqueous ink absorption leads to curling and skewing, which complicates transportation and post-processing tasks, such as stapling and punching, as existing alignment mechanisms struggle to correct significant skew angles.

Innovation Solution

The introduction of a correction roller system within the intermediate unit, where pairs of transportation rollers are strategically positioned to correct skew by releasing forces sequentially and positioning the correction rollers close to the carry-out port, ensuring proper alignment and preventing jamming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional alignment members are used to align paper sheets, then alignment is achieved for slightly skewed sheets, but significant skew angles prevent appropriate alignment and post-processing

Engineering Contradiction:
Improvealignment precisionVSAvoidhandling capability for skewed sheets
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The skew correction mechanism is positioned upstream in the transportation path to correct skew angles before the paper sheets reach the alignment member and post-processing unit. This preliminary correction enables the alignment member to effectively align sheets that would otherwise be too skewed, and ensures post-processing can proceed without skew-related failures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The skew correction mechanism acts as an intermediary device between the transportation path and the alignment/post-processing sections. It mediates the skew issue by actively correcting the paper sheet orientation, allowing the subsequent alignment and post-processing operations to function properly despite incoming skew.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If paper sheets are transported through the intermediate unit, then transportation is achieved, but skew occurs due to eccentric rotation axes and curling

Engineering Contradiction:
Improvetransportation efficiencyVSAvoidskew angle
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The skew correction mechanism extracts the skew component from the paper sheet transportation process. By actively counteracting and removing the skew that develops during transportation, the system maintains both efficient transportation and precise alignment, as the skew is taken out before affecting subsequent operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If correction rollers are positioned far from the carry-out port, then there is more space for mechanism placement, but alignment effectiveness decreases and jamming risk increases

Engineering Contradiction:
Improvemechanism placement flexibilityVSAvoidalignment effectiveness
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The correction rollers are positioned to act on the paper sheets as close as possible to the carry-out port, performing the skew correction at the latest possible moment in the transportation sequence. This ensures maximum alignment effectiveness while still allowing adequate space for the mechanism's structural requirements.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3269552B1Intermediate unit, post processing device, and printing apparatus
Publication Date: 2020.02.12 SEIKO EPSON CORP
  • EP3269552B1 patent drawingFigure 1
  • EP3269552B1 patent drawingFigure 2
  • EP3269552B1 patent drawingFigure 3

AI summary

A medium, of which skew is appropriately corrected, is fed from an intermediate unit to a post processing unit so as to suppress an adverse effect of the skew of the medium in the post processing unit.