Belt Speed Control via Mark Detection in Tandem Image Formers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tandem-type image forming apparatuses face challenges in maintaining consistent belt speed due to eccentricity and uneven thickness, leading to color shifts and image quality deterioration, as existing solutions do not completely prevent velocity fluctuations across the entire belt circumference.
Innovation Solution
An image forming apparatus with a plurality of image carriers and belt supporting members, featuring a contact and separation mechanism with a mark detector to accurately detect scale marks on the belt, allowing for precise control of the belt speed to mitigate color shifting caused by velocity fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a belt member with scale and mark detection system is used to control belt speed, then color shift is reduced, but device complexity increases
Solution Approach 1:
The patent implements a feedback control system where scale marks on the belt member are detected by sensors, and the detected position information is fed back to the controller to adjust the belt drive motor speed, thereby maintaining consistent belt speed and preventing color shift in the transferred toner images
Solution Approach 2:
The patent replaces mechanical speed control methods with an optical/electronic detection system that uses scale marks and sensors to detect belt speed and position, substituting complex mechanical adjustments with a more precise electronic feedback control mechanism
2Productivity
If contact and separation mechanism is used to control photoconductor engagement, then unnecessary driving is prevented, but measurement precision of belt speed detection may be compromised
Solution Approach 1:
The patent positions the scale marks on the belt member in advance at known locations, allowing the detection system to reference these pre-placed marks for accurate speed measurement even when the contact and separation mechanism is active
Solution Approach 2:
The patent introduces scale marks as an intermediary reference system that mediates between the contact and separation mechanism and the speed detection system, allowing accurate measurement without requiring continuous contact between all components
Data Source
AI summary
An image forming apparatus includes a plurality of N image carriers including first through Nth image carriers, a transfer unit including an endless transfer belt, a plurality of M belt supporting members including a plurality of first through Nth nip opposing members contacting the inner surface of the endless transfer belt at positions corresponding to where the plurality of N image carriers contacts the outer surface of the endless transfer belt to form N transfer nips thereat, the first opposing member defining a first supported area of the endless transfer belt, a contact and separation mechanism including a retaining unit to move the first supported area of the endless transfer belt into and out of contact with the first image carrier, and a mark detector to detect a plurality of adjacent marks formed at a predetermined pitch in a circumferential direction of the endless transfer belt.