Ejection Roller Skew Control for Consistent Media Alignment

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Solution Overview

Problem

Medium ejecting apparatuses face issues with media alignment on the ejection tray, leading to distorted images due to variations in imaging or image formation positions when the conveyance speed is adjusted to align the media.

Innovation Solution

The apparatus includes a conveyance roller, an ejection roller, a motor, and a media sensor to detect skew and control the ejection roller based on the skew amount before the medium's trailing end passes the ejection roller, ensuring proper alignment and consistent image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the conveyance speed is changed to align the media ejected onto the ejection tray, then the media alignment is improved, but the intervals of imaging positions or image formation positions on one medium vary causing image distortion

Engineering Contradiction:

Improvemedia alignmentVSAvoidimage position consistency

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The system performs preliminary detection of media skew using a media sensor before the media reaches the ejection roller. Based on this detection, the control unit calculates the required skew correction amount and adjusts the ejection roller speed in advance, allowing alignment correction without affecting imaging position consistency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The media sensor provides real-time feedback on media skew position and orientation. The control unit uses this feedback to dynamically adjust the ejection roller speed, creating a closed-loop control system that corrects alignment while maintaining consistent imaging intervals

Inventive Principle:

Principle #23Feedback

2Shape

If the ejection roller speed is adjusted to correct skew, then media alignment is improved, but the timing of medium detection by the media sensor becomes inaccurate

Engineering Contradiction:

Improvemedia alignmentVSAvoidskew detection accuracy

Core Design Contradiction:

ShapeVSMeasurement precision

Solution Approach 1:

The media sensor detects media skew at a position upstream from the ejection roller, performing the measurement before the ejection speed adjustment occurs. This preliminary detection ensures accurate skew measurement is obtained while the media is still traveling at constant conveyance speed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system separates the detection function from the correction function by placing the media sensor at a different location than the ejection roller. The detection occurs in the conveyance section while correction occurs at the ejection section, allowing independent optimization of both functions

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250367947A1Medium ejecting apparatus, medium ejecting method, and computer-readable non-transitory recording medium

Publication Date: 2025.12.04 PFU LTD

AI summary

A medium ejecting apparatus includes a conveyance roller to convey a medium, a processing device to perform a predetermined processing relative to the medium conveyed by the conveyance roller, an ejection roller located downstream from the processing device in a medium ejecting direction to eject the medium subjected to the predetermined processing, a motor to drive the conveyance roller and the ejection roller, a first media sensor located between the conveyance roller and the processing device to detect the medium, and circuitry. The circuitry detects a skew amount of the medium, and controls the ejection roller based on a detection result by the first media sensor and the skew amount before a trailing end of the medium passes the ejection roller.