Image Forming Apparatus Linear Velocity Difference Correction

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Solution Overview

Problem

Image forming apparatuses face challenges in timely adjustment of image forming conditions due to linear velocity differences between the latent image bearer and the intermediate transfer member, leading to uneven image density and potential image failures like wormhole images.

Innovation Solution

An image forming apparatus that includes an image bearer, a toner image forming device, a transfer rotator, a transfer device, a rotation position detector, an image density detector, and a correction unit, which forms an adjustment toner image and acquires image density unevenness data to adjust the image forming conditions based on the detected data and linear velocity difference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the linear velocity of the latent image bearer is made different from that of the intermediate transfer member to inhibit wormhole images, then image failure is suppressed, but timely adjustment of image forming conditions is hindered

Engineering Contradiction:
Improveimage formation stabilityVSAvoidadjustment timing delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing timing correction in advance based on the known linear velocity difference. The correction amount is calculated beforehand and stored, then applied when adjusting image forming conditions. This ensures that even with different linear velocities, the adjustment timing remains synchronized with the latent image bearer's rotation cycle, preventing delays while maintaining image formation stability.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the linear velocity of the latent image bearer is made identical to that of the intermediate transfer member for timely adjustment, then adjustment timing is synchronized, but wormhole images occur

Engineering Contradiction:
Improveadjustment timing synchronizationVSAvoidimage formation stability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the timing parameter based on the linear velocity difference. Instead of maintaining a fixed timing relationship, the system calculates and applies a correction amount that compensates for the velocity difference. This allows the latent image bearer and intermediate transfer member to operate at different linear velocities (preventing wormhole images) while maintaining synchronized adjustment timing through the timing correction parameter.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If image forming conditions are adjusted based on detection result with reference to home position, then cyclic unevenness in image density is suppressed, but adjustment timing becomes inaccurate due to linear velocity difference

Engineering Contradiction:
Improveimage density uniformityVSAvoiddetection timing accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using the detection result of the toner pattern to determine the necessary timing correction amount. The system detects image density unevenness, calculates the correction amount based on the linear velocity difference and detection timing, then applies this correction to synchronize future adjustments with the latent image bearer's rotation cycle. This feedback loop ensures both image density uniformity and detection timing accuracy are maintained despite different linear velocities.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2955581B1Image forming apparatus and method adjusting image forming condition
Publication Date: 2017.05.03 RICOH CO LTD
  • EP2955581B1 patent drawingFigure 1
  • EP2955581B1 patent drawingFigure 2
  • EP2955581B1 patent drawingFigure 3

AI summary

An image forming apparatus (100) includes an image bearer (2); a toner image forming device (10); a transfer rotator (1); a transfer device (6); a rotation position detector (18; 70); an image density detector (30); a density data acquisition unit (300) to causes the toner image forming device (10) to form an adjustment toner image equal to or greater in length than a circumferential length of the image bearer (2), cause a linear velocity difference between the image bearer (2) and the transfer rotator (1) in transfer of the adjustment toner image, and acquires, from a detected image density of the toner image transferred from the image bearer (2), detected by the image density detector (3 0), image density unevenness data with reference to detection of a reference rotation position of one of the image bearer (2) and a rotator (5a); and a correction unit (37) to adjust an image forming condition according to the reference rotation position, the image density unevenness data, and the linear velocity difference.