Density Correction Unit Rotation Period Determination

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Solution Overview

Problem

Current image forming apparatuses require a lengthy calibration process to accurately determine the rotation period of an intermediate transfer belt, which is prone to fluctuations due to belt length dispersion, expansion, contraction, and rotational speed variations, leading to incorrect toner density measurements.

Innovation Solution

An image forming apparatus with a density sensor and a density correction unit that measures the rotation period by calculating differences in density measurement values between two rounds and determining the rotation period based on the correlation between section background data, allowing for accurate toner density determination and correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If background data is determined by calculating rotation period based on belt length and rotational speed, then the calibration process can be simplified, but the measurement precision deteriorates due to dispersion of belt round length, expansion/contraction of belt, and fluctuation of rotational speed

Engineering Contradiction:

Improvecalibration processVSAvoidbackground data positioning

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical calculation method (using belt length and rotational speed) with an optical measurement method (using a sensor to detect actual belt position). The sensor directly measures the belt's actual rotation characteristics, eliminating the need for complex mechanical calculations and avoiding errors from belt length dispersion and expansion/contraction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the belt's own rotation to generate the measurement signal. The sensor detects reflectance changes caused by the belt's rotation, and the system calculates the rotation period directly from these detected signals. This self-service approach eliminates the need for external reference markers or complex synchronization mechanisms.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If at least two rounds of the image carrier are required to determine the belt rotation period, then the measurement precision is improved, but the calibration time increases significantly

Engineering Contradiction:

Improverotation period determinationVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by determining the rotation period from only one round of the belt rotation rather than requiring two or more rounds. The sensor detects reflectance changes during a single rotation cycle, and the system calculates the rotation period from this single round of data, significantly reducing calibration time while maintaining sufficient measurement precision.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If background data is read corresponding to the position where toner pattern is formed, then the toner density measurement can be performed, but the reliability deteriorates when the determined position does not match the actual toner pattern position due to belt length dispersion and rotational speed fluctuation

Engineering Contradiction:

Improvetoner density measurementVSAvoidposition correspondence

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback by continuously monitoring the belt's actual rotation characteristics through the sensor and using this information to dynamically determine the correct position for reading background data. The system calculates the rotation period from actual sensor data and uses this feedback to accurately locate the toner pattern position, ensuring reliable correspondence between the read background data and the actual toner pattern.

Inventive Principle:

Principle #23Feedback

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

This approach reduces calibration time and ensures accurate toner density measurements by determining the rotation period and correcting density characteristics, thereby stabilizing the toner density control process.

Implementation Method 1

a reflectance (a reflection light intensity) of the intermediate transfer belt or the like is measured as a background

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

determines the rotation period on the basis of a correlation between the section background data at the first round and the section background data at the second round

Methodology Applied

Scientific EffectCorrelation analysis:

Data Source

PatentUS9946209B2Image forming apparatus

Publication Date: 2018.04.17 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A density correction unit (a1) obtains density measurement values of a surface in a measurement section of an image carrier at a first round, (a2) calculates as section background data at the first round respective differences between the density measurement values at the first round and an average value thereof, (a3) obtains density measurement values of a surface at least in the measurement section at a second round, (a4) calculates as section background data at the second round respective differences between the density measurement values at the second round and an average value thereof in a specific section with the same length as the measurement section, and (a5) determines the rotation period on the basis of a correlation between the section background data at the first round and at the second round. Here the measurement section is a part in a circulating direction of the image carrier.