Mark Detector Variation Prevention for Belt Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrophotographic image forming apparatuses with endless belt members, variations in belt velocity and position due to load changes and deformation cause detection errors when optically detecting marks, leading to inaccurate image positioning on paper.
Innovation Solution
A mark detector with a variation prevention part that holds the endless belt member in place to stabilize the light illumination surface, combined with a drive controller that adjusts the drive force based on mark detection signals to control belt velocity and position accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If marks are optically detected on the moving endless belt member, then belt velocity and position can be controlled, but detection errors occur due to belt thickness variation and vibration
Solution Approach 1:
A transparent cover is introduced as an intermediary component between the mark sensor and the endless belt member. This cover protects the optical detection system from direct exposure to belt thickness variations and vibrations, thereby maintaining stable and accurate mark detection despite the unstable motion environment of the belt.
Solution Approach 2:
The transparent cover serves as a cushioning element that compensates for the effects of belt thickness variation and vibration before they reach the mark sensor. By positioning this protective element in advance, the system pre-mitigates detection errors that would otherwise occur during belt operation.
2Productivity
If the endless belt member moves under load variations, then the belt conveys images, but velocity and position variations cause positioning errors
Solution Approach 1:
The mark sensor detects the position and velocity of the endless belt member by reading marks on the belt surface. This detection information is fed back to the control system, which adjusts the drive mechanism to compensate for velocity and position variations, thereby maintaining accurate image positioning despite load variations during belt operation.
Solution Approach 2:
The patent replaces direct mechanical coupling methods with optical detection using marks and a mark sensor. Instead of relying solely on mechanical transmission accuracy, the system uses optical mark detection to monitor and control belt position and velocity, achieving higher precision in image positioning.
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 configuration reduces detection errors and ensures high-accuracy control of belt movement, improving image quality by maintaining consistent mark detection and minimizing timing errors.
Implementation Method 1
a light emitting element that emits a light beam; a light receiving element that receives reflected light from the light illumination surface
Data Source
AI summary
A mark detector optically detecting a scale having multiple marks formed successively at predetermined intervals along the moving direction of an endless belt member, and outputting an electrical signal corresponding to the presence or absence of the marks when the endless belt member moves is disclosed. The mark detector includes a light illumination part configured to illuminate the light illumination surface of the endless belt member on which surface the scale is formed with parallel light rays; a light receiving part configured to receive reflected light from the light illumination surface; and a variation prevention part configured to prevent a variation of the light illumination surface. The variation prevention part includes a holding member configured to hold the endless belt member in the vicinity of the light illumination surface movably in the moving direction from the exterior surface side and the interior surface side of the endless belt member.