Transfer Cylinder Speed Variation Density Correction

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Solution Overview

Problem

Existing image forming apparatuses face challenges in correcting density unevenness caused by unexpected vibrations, such as those resulting from collisions between the gripper storage space of the transfer cylinder and the transfer belt, which are not addressed by existing techniques that rely on constant cycle corrections.

Innovation Solution

An image forming apparatus equipped with a processor that corrects density unevenness by using information related to speed variations of the transfer body, obtained from sensors, to adjust the density of the developer image during transfer, thereby reducing density variations in the printed image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a transfer cylinder with gripper storage space is used to improve paper transport performance, then paper gripping and transport capability is improved, but vibration and speed variation occur due to collision between the gripper storage space corner and transfer belt

Engineering Contradiction:

Improvepaper transport performanceVSAvoidspeed variation stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection of speed variation using a sensor before the collision occurs, and pre-calculates the correction amount for density unevenness. This allows the system to compensate for the upcoming vibration effect, maintaining image quality despite the inevitable collision when the gripper storage space corner contacts the transfer belt.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A sensor detects the actual speed variation of the transfer belt in real-time and feeds this information back to the controller. The controller then adjusts the density correction based on the detected speed variation, creating a closed-loop control system that continuously compensates for vibrations caused by gripper storage space collisions.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If constant cycle density correction is applied to correct roller deflection density unevenness, then periodic density unevenness is corrected, but unexpected vibration with no constant period cannot be corrected

Engineering Contradiction:

Improvedensity uniformityVSAvoidcorrection capability for various vibration types

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system transitions from static constant cycle correction to dynamic real-time correction. The sensor continuously monitors speed variation, and the controller dynamically adjusts the density correction amount based on actual conditions. This allows the system to adapt to both periodic roller deflection and unexpected aperiodic vibrations caused by gripper storage space collisions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The correction amount for density unevenness is changed from a fixed constant cycle value to a variable value that changes based on detected speed variation. The controller modifies correction parameters in real-time according to the actual vibration conditions, enabling correction of various types of density unevenness regardless of their periodicity.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If density correction is performed using constant cycle method, then correction process is simple, but correction accuracy for unexpected vibration is insufficient

Engineering Contradiction:

Improvecorrection process simplicityVSAvoiddensity correction accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system replaces complex mechanical constant cycle correction mechanisms with a sensor-based detection and control system. By using electronic sensing of speed variation and electronic control of density correction, the system achieves higher precision while maintaining relatively simple implementation through software/control logic rather than complex mechanical adjustments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240168423A1Image forming apparatus and non-transitory computer readable medium storing program

Publication Date: 2024.05.23 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes: a transporter including a gripper to grip a recording medium; an image former that forms a developer image on a transfer body; a transferrer that transfers the developer image to the recording medium by bringing the transfer body with the developer image formed into contact with a transfer cylinder having space to store the gripper; and a processor configured to: correct a density of the developer image formed in the image former, using information related to speed variation of the transfer body when the developer image is transferred to the recording medium, so that density unevenness in an image formed on the recording medium is reduced.