Pulse Timing Generation for Rotary Encoder Cogging Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The use of a rotary encoder in image forming apparatuses leads to printing unevenness due to cogging fluctuations in motor rotation, which affects image quality.

Innovation Solution

A pulse generator is employed to generate timing pulses based on detection signals from a rotary encoder, calculating time intervals between signal outputs to suppress deviations caused by cogging, using an average of multiple time information points to determine output timing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If a rotary encoder is used to detect carriage position and speed, then the linear encoder can be replaced and maintenance becomes easier, but printing unevenness occurs due to cogging fluctuations affecting image quality

Engineering Contradiction:

Improvelinear encoder replacementVSAvoidprinting uniformity

Core Design Contradiction:

Ease of repairVSManufacturing precision

Solution Approach 1:

The system uses feedback from the rotary encoder to detect actual motor rotation deviations caused by cogging, then compensates for these deviations in the timing pulse generation to maintain accurate discharging timing despite the cogging fluctuations

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention changes the parameter used for timing pulse generation from direct rotary encoder pulses to compensated timing based on multiple time interval measurements, transforming the raw encoder signal into a corrected timing signal that accounts for cogging effects

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If timing pulses are generated directly from rotary encoder signals, then the system is simple, but cogging fluctuations cause discharging timing deviations

Engineering Contradiction:

Improvetiming pulse generation systemVSAvoiddischarging timing accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurements of multiple time intervals between detection signals before generating the final timing pulse, using these pre-measured values to calculate an average that compensates for cogging-induced timing deviations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of using a single detection signal for timing, the system excessively measures multiple time intervals between consecutive detection signals and uses the average of these measurements, thereby obtaining more accurate timing information that compensates for cogging fluctuations

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12381495B2Pulse generator

Publication Date: 2025.08.05 BROTHER KOGYO KK

AI summary

There is provided a pulse generator generating a timing pulse based on a detection signal obtained from a detection signal outputting part configured to output the detection signal every time a motor rotates by a predetermined amount which has been previously set. The pulse generator includes: a time information calculating part, and a timing determining part. A time difference between a first calculating timing at which first time information is calculated and a second calculating timing at which second time information is calculated is longer than a time required for the motor to rotate by not less than an angle corresponding to a cogging distance.