Pickup Roller Dynamics for Consistent Media Pressure

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Solution Overview

Problem

Existing image forming apparatuses face issues with inconsistent pickup pressure of printing media, leading to either multiple sheets being supplied at once or none being supplied, due to varying quantities of loaded media.

Innovation Solution

A printing medium supply device with a pickup unit featuring a shaft, a pickup roller, a pivotally rotated pickup holder, a link member, and an adjustment unit with a pressure member and elastic member, allowing the pickup roller to maintain consistent pressure based on the quantity of media loaded, ensuring reliable single-sheet pickup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed pickup roller is used, then the structure is simple, but the pickup pressure varies with the quantity of loaded printing media causing unreliable pickup

Engineering Contradiction:
Improvepickup reliabilityVSAvoidpickup unit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pickup roller is made dynamically adjustable through a pivot holder that can rotate about a shaft, allowing the roller to move vertically in response to the quantity of loaded printing media. This dynamic adjustment ensures consistent pickup pressure whether few or many sheets are loaded, resolving the reliability issue without requiring complex active control systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The position of the pickup roller is changed as a parameter in response to the quantity of loaded media. By varying the vertical position of the roller through the pivot holder mechanism, the system adapts to different media quantities and maintains optimal pickup pressure, achieving reliable pickup across varying conditions

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the pickup roller position is fixed, then the mechanism is simple, but multiple sheets or no sheets may be supplied at once

Engineering Contradiction:
Improvesingle-sheet pickup accuracyVSAvoidpickup holder mechanism
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pickup holder rotates about a shaft to dynamically adjust the roller position, ensuring that only one sheet is picked up at a time by maintaining appropriate contact pressure. This dynamic adjustment prevents both multiple-sheet pickup and failure to pickup, improving single-sheet accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pivot holder acts as an intermediary mechanism between the fixed shaft and the pickup roller. It translates the varying media quantity into appropriate roller position adjustments, mediating the interaction to achieve reliable single-sheet pickup without direct complex control

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the pickup roller is lowered for few sheets, then pickup pressure is sufficient, but the structure cannot adapt to varying media quantities

Engineering Contradiction:
Improveadaptation to media quantityVSAvoidadjustable pickup mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pickup mechanism is made dynamic through the pivot holder that can rotate to different positions based on media quantity. When few sheets are loaded, the holder rotates to lower the roller for sufficient pressure; when many sheets are loaded, it positions the roller higher. This dynamic adaptability resolves the contradiction between adaptability and complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pickup mechanism serves itself by automatically adjusting the roller position in response to the media quantity through the pivot holder rotation. The system self-adapts to different loading conditions without external control, achieving versatility while keeping the mechanism relatively simple

Inventive Principle:
Principle #25Self-service

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

The solution enhances pickup performance by varying the pickup pressure according to the quantity of printing media, preventing multiple sheets from being supplied simultaneously or none being supplied, thereby improving the reliability of the image forming process.

Implementation Method 1

an elastic member elastically supported by the pressure member to transmit elastic force to the link member

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2996974B1Printing medium supply device and image forming apparatus having the same
Publication Date: 2020.09.09 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2996974B1 patent drawingFigure 1~2
  • EP2996974B1 patent drawingFigure 3
  • EP2996974B1 patent drawingFigure 4~5

AI summary

A printing medium supply device and an image forming apparatus having the same are provided. The printing medium supply device may include a pickup unit and an adjustment unit. The pickup unit may include a shaft, a pickup roller spaced apart from the shaft to come into contact with printing media, a pickup holder to support the pickup roller, the pickup holder being rotated about the shaft to lift or lower the pickup roller, and a link member connected to the pickup holder so as to be rotated about the shaft. The adjustment unit may include a pressure member coming into contact with a pressure applied portion of the link member to rotate the link member by applying pressure thereto, and an elastic member elastically supported by the pressure member to transmit elastic force to the link member. This configuration ensures constant pickup pressure despite variation in the quantity of printing media.