Rotary Support Phase Detection in Color Electrophotographic Apparatus

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Solution Overview

Problem

The downsizing of color electrophotographic image forming apparatuses leads to increased error in detecting the phase of the rotary support member, affecting the precision of stopping developing devices at the developing position, resulting in inaccurate image formation.

Innovation Solution

A color electrophotographic image forming apparatus that includes a rotary support member with a first member and a second member, detected by sensors to accurately determine the phase of the rotary support member, allowing precise positioning and operation of developing devices, even in a smaller form factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the main body of the color electrophotographic image forming apparatus is downsized, then the size of the apparatus is reduced, but the detection error of the phase of the rotary support member increases

Engineering Contradiction:

Improvesize of apparatusVSAvoiddetection error of phase

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

A sensor flag is introduced as an intermediary element attached to the rotary support member. This flag serves as a visual marker that the sensor can detect, enabling accurate phase detection of the rotary support member even in the downsized apparatus configuration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the detection parameter from direct positional measurement to optical detection of the sensor flag. By using optical parameters (light reflection/detection) instead of mechanical measurement parameters, the system achieves accurate phase detection in a compact space.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the position of the sensor flag is moved closer to the center of rotation of the rotary support member, then the apparatus can be downsized, but the variation error of detective precision increases

Engineering Contradiction:

Improveapparatus sizeVSAvoiddetective precision variation error

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The sensor flag acts as an intermediary that amplifies the detection signal. Even though positioned close to the center of rotation, the flag provides a distinct optical marker that the sensor can reliably detect, maintaining detection precision despite the reduced radial distance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical phase detection methods with optical detection using the sensor flag. This substitution allows for accurate phase detection even when the detection point is close to the center of rotation, where mechanical leverage would be insufficient.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If the apparatus is downsized, then compactness is improved, but the precision to stop the developing device at the developing position deteriorates

Engineering Contradiction:

Improveapparatus compactnessVSAvoidprecision to stop developing device

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The sensor continuously monitors the position of the sensor flag on the rotary support member, providing feedback to the control system. This feedback mechanism enables precise control of the rotary support member's position, ensuring accurate stopping at the developing position even in the downsized apparatus.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical positioning systems with an optical detection and control system using the sensor flag. This substitution enables precise positional control in a compact configuration, as the optical system requires less space than traditional mechanical positioning mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8170450B2Color electrophotographic image forming apparatus that utilizes a rotatable rotary support member to support a plurality of developing devices

Publication Date: 2012.05.01 CANON KK

AI summary

A color electrophotographic image forming apparatus to form an image on a recording medium may include a photosensitive member, a rotary support member, a first member, a second member, and a controlling unit. The photosensitive member forms an electrostatic latent image. The rotary support member moves a developing device to a developing position to develop the electrostatic latent image by rotation. The first member rotates multiple times of a natural number when the rotary support member rotates once and moves together with the rotary support member. The second member moves together with the rotary support member. A first sensor detects a rotation of the first member and a second sensor detects the rotary support member as positioned at a predetermined phase. The controlling unit detects a phase of the rotary support member by a first signal from the first sensor and a second signal from the second sensor.