Developing Roller Rotation Cycle Detection via AC Current Analysis

Solution Overview

Problem

Existing image forming apparatuses face challenges in correcting image density unevenness caused by the rotation cycle of rotating bodies like developing rollers without increasing space or cost by incorporating a detector to detect the rotation cycle.

Innovation Solution

An image forming apparatus that forms test images with varying correction amounts and periodic images indicating the rotation cycle, allowing users to determine the appropriate correction without a detector for the rotating body, by controlling the image forming device to adjust the DC voltage based on alternating current measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a detector for detecting the rotation cycle of the rotating body is provided in the rotating body, then the rotation cycle can be detected, but the space occupied by the rotating body increases and the cost increases

Engineering Contradiction:

Improverotation cycle detectionVSAvoidspace occupied by rotating body

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent uses an intermediary approach by detecting the rotation cycle of the developing roller through the alternating current signal generated during the image forming process, rather than using a direct detector mounted on the roller. The controller analyzes the AC component of the current supplied to the developing roller to extract rotation cycle information, thereby obtaining the required measurement without adding physical detectors to the rotating body.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces a mechanical detection system (physical detector on the roller) with an electrical measurement system. By measuring the alternating current characteristics during the image forming process, the rotation cycle is detected through electrical signals rather than mechanical sensors, eliminating the need for additional space on the rotating body.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a detector for detecting the rotation cycle of the rotating body is provided in the rotating body, then the rotation cycle can be detected, but the cost increases

Engineering Contradiction:

Improverotation cycle detectionVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses an intermediary approach by detecting the rotation cycle of the developing roller through the alternating current signal generated during the image forming process, rather than using a direct detector mounted on the roller. The controller analyzes the AC component of the current supplied to the developing roller to extract rotation cycle information, thereby obtaining the required measurement without adding physical detectors to the rotating body.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces a mechanical detection system (physical detector on the roller) with an electrical measurement system. By measuring the alternating current characteristics during the image forming process, the rotation cycle is detected through electrical signals rather than mechanical sensors, eliminating the need for additional space on the rotating body.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 3:

The developing roller itself generates the detection signal through its normal operation. The alternating current required to drive the developing roller also serves as the detection medium, as the AC component naturally reflects the rotation cycle. This self-service approach eliminates the need for separate detection components and reduces manufacturing cost.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If multiple test images with different correction amounts are formed on sheets to determine appropriate correction, then image density unevenness can be corrected, but additional images indicating rotation cycle are needed for user determination

Engineering Contradiction:

Improveimage density uniformityVSAvoidcomplexity of test image formation

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the rotation cycle indication function with the existing test image formation process. By forming pointing portions (marks) at positions corresponding to the rotation cycle intervals on the same sheet as the test images, the system combines multiple functions into a single integrated test pattern, reducing overall complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent adds a spatial dimension to the test images by incorporating pointing portions at specific positions that correspond to rotation cycle intervals. These marks are arranged in the sub-scanning direction at intervals matching the rotation cycle, providing visual reference information without requiring separate test sheets or additional complex mechanisms.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11112741B2Image forming apparatus and non-transitory computer readable medium

Publication Date: 2021.09.07 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes an image forming device, a corrector, and a controller. The image forming device is configured to form an image on a sheet using a rotating body under a predetermined image forming condition. The corrector is configured to correct the image forming condition to adjust image density unevenness corresponding to a rotation cycle of the rotating body. The controller is configured to control the image forming device to form on at least one sheet (i) plural test images that are different in correction amount for the image forming condition and (ii) pointing portions indicating intervals corresponding to the rotation cycle of the rotating body, in a state where the rotating body is continuously rotated.