Conveyor Roller Velocity Control for Paper Deflection

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Solution Overview

Problem

Conventional image forming apparatuses face challenges in preventing unnecessary deflection of recording paper or documents at the registration roller pair, leading to increased space requirements and reduced performance, especially in high-speed applications.

Innovation Solution

A recording paper conveying device and document feeding device are designed with a registration roller pair and a conveyor roller pair, where the conveyor roller pair rotates to cause the leading edge of the paper or document to abut the registration roller pair, and then the rotation is suspended or decelerated for a prescribed time before being restarted or accelerated, allowing for precise deflection control without excessive buckling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the pre-registration roller pair rotates at constant velocity to deflect the sheet, then the sheet is deflected by a prescribed amount, but unnecessary excess deflection occurs leading to increased space requirements

Engineering Contradiction:

Improvedeflection precisionVSAvoidspace for holding deflected paper

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The pre-registration roller pair dynamically adjusts its rotation velocity during the deflection process. The velocity is controlled to increase during the deflection period and then decrease when the sheet leading edge contacts the registration roller pair, preventing excess deflection and reducing the space needed for holding deflected paper.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The pre-registration roller pair implements periodic velocity changes during the deflection process. The velocity is increased during the deflection period and then decreased when the sheet contacts the registration roller pair, creating a controlled periodic action that prevents unnecessary excess deflection.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If the pre-registration roller pair rotates at low velocity corresponding to self-start frequency, then the sheet is deflected by a prescribed amount, but the image forming process time increases reducing productivity

Engineering Contradiction:

Improvedeflection precisionVSAvoidimage forming speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The pre-registration roller pair uses dynamic velocity control, increasing the rotation velocity during the deflection process rather than maintaining a constant low velocity. This allows the sheet to be deflected by a prescribed amount while reducing the overall process time, thereby improving productivity without sacrificing deflection precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The rotation velocity parameter of the pre-registration roller pair is changed during the deflection process. The velocity is controlled to increase during deflection and then decrease when contact is made, allowing for both precise deflection control and improved image forming speed.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the pre-registration roller pair rotates at high velocity close to process velocity, then productivity is improved, but unnecessary excess deflection and buckling occur

Engineering Contradiction:

Improveimage forming speedVSAvoiddeflection control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The pre-registration roller pair implements dynamic velocity control, adjusting the rotation velocity during the deflection process. The velocity is increased during deflection and then decreased when the sheet contacts the registration roller pair, preventing unnecessary excess deflection and buckling while maintaining high productivity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The pre-registration roller pair uses periodic velocity changes during the deflection process. The velocity is controlled to increase during the deflection period and then decrease when contact is made, creating a controlled periodic action that prevents excess deflection and buckling while improving image forming speed.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS8950747B2Recording paper conveying device, document feeding device and image forming apparatus including these devices

Publication Date: 2015.02.10 SHARP KK

AI summary

A recording paper conveying device includes a registration roller pair and a conveyor roller pair adjacent to the registration roller pair. By rotating the conveyor roller pair, a sheet of recording paper is fed until leading edge of the sheet abuts the registration roller pair in stationary state so that the sheet is deflected by a prescribed amount. Then, conveyor roller pair is rotated at the constant velocity, and while the sheet is kept deflected, rotation of the registration roller pair is started, to start feeding of the sheet by the registration roller pair. While the registration roller pair is kept rotating, rotation of the conveyor roller pair is suspended, and then, the conveyor roller pair is returned to the state of rotation before suspension. Thus, unnecessary deflection of the sheet just in front of the registration roller pair can be prevented.