Image Forming Speed Adjustment for Consistent Output Quality

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Solution Overview

Problem

Existing image forming apparatuses experience variations in image quality due to changes in toner charge over time, leading to differences in output image quality across different image forming speeds, complicating control when adjusting at specific sheet counts.

Innovation Solution

The apparatus executes adjustment processing at a common execution timing for all speeds, specifically when the developing device drive time reaches an integer multiple of a reference time, adjusting developing bias voltage, light emission, table data, and image position to maintain consistent image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If adjustment processing is executed at specific sheet counts for each image forming speed, then image quality can be maintained for each speed, but control complexity increases and variations in image quality across different speeds cannot be suppressed

Engineering Contradiction:
Improveimage quality consistencyVSAvoidcontrol logic complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the adjustment processing into two independent components: (1) a common adjustment execution timing that is unified across all image forming speeds, and (2) speed-specific adjustment parameters stored in a table. This segmentation allows the control logic to use a simple unified timing mechanism while maintaining speed-appropriate adjustment values, thereby reducing overall control complexity while preserving image quality consistency across different speeds

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal adjustment execution timing that serves all image forming speeds simultaneously. Instead of having separate adjustment timings for each speed, a single unified timing mechanism is implemented that triggers adjustment processing for all speeds, reducing control logic complexity while maintaining the ability to handle speed-specific variations through parameter tables

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If adjustment processing is executed at a fixed sheet count, then control is simple, but image quality variations occur across different image forming speeds

Engineering Contradiction:
Improvecontrol simplicityVSAvoidimage quality consistency
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using a unified adjustment execution timing for all speeds while storing speed-specific adjustment parameters in a table. This allows the system to maintain simple control logic at the timing level while applying locally optimized parameters for each image forming speed, thereby achieving both control simplicity and image quality consistency across different speeds

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If adjustment processing is executed frequently to maintain image quality, then image quality variation is reduced, but processing time increases

Engineering Contradiction:
Improveimage quality variation suppressionVSAvoidadjustment processing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements periodic adjustment processing by executing adjustments at fixed, predetermined intervals (e.g., every N sheets) rather than continuously or at every sheet. This periodic approach balances image quality maintenance with processing efficiency, ensuring quality control without excessive time loss. The unified timing mechanism across all speeds optimizes the interval to prevent both over-adjustment and under-adjustment

Inventive Principle:
Principle #19Periodic action

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 suppresses variations in image quality across multiple speeds with simpler control, ensuring consistent output image quality without complicating the apparatus's control logic.

Implementation Method 1

an image carrier on which an electrostatic latent image is formed

Methodology Applied
Scientific EffectElectrostatic latent image formation: Electrostatic Induction

Implementation Method 2

a developing portion configured to use toner to develop the electrostatic latent image formed on the image carrier

Methodology Applied
Scientific EffectElectrostatic development: Electrostatic Induction

Data Source

PatentEP4685569A1Image forming apparatus and adjustment method capable of suppressing occurrence of difference in amount of variation in image quality of output image among plurality of image forming speeds with simple control
Publication Date: 2026.01.28 KYOCERA DOCUMENT SOLUTIONS INC
  • EP4685569A1 patent drawingFigure 1
  • EP4685569A1 patent drawingFigure 2
  • EP4685569A1 patent drawingFigure 3

AI summary

An image forming apparatus (100) includes an image forming portion (3), an image formation processing portion (51), and an adjustment processing portion (52). The image forming portion (3) includes an image carrier (31) on which an electrostatic latent image is formed and a developing portion (33) configured to use toner to develop the electrostatic latent image formed on the image carrier (31), and forms an image on the sheet conveyed by the sheet conveying portion (4). The image formation processing portion (51) executes image formation processing for forming an image on each of the sheets sequentially conveyed using the image forming portion (3) at any of a plurality of predetermined image forming speeds. The adjustment processing portion (52) executes adjustment processing for adjusting an image quality of an output image output by the image forming portion (3) each time an execution timing common to the plurality of image forming speeds arrives during the execution of the image formation processing.