Image Forming Apparatus Conveyance Speed Detection Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in detecting conveyance speed of continuous sheets with low friction coefficients or surface irregularities, leading to potential print failures and waste due to inadequate feedback control.
Innovation Solution
The apparatus employs a first and second conveyance member with a controller that determines if the conveyance speed can be normally detected by measuring the first conveyance speed, allowing for timely determination and prevention of print failures and waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact sensor including a rotary encoder is used to detect conveyance speed, then the conveyance speed can be detected under normal conditions, but the conveyance speed cannot be detected normally when the continuous sheet has a low friction coefficient or surface irregularities
Solution Approach 1:
A detection sheet with a predetermined friction coefficient and smooth surface is introduced as an intermediary medium between the contact sensor and the actual continuous sheet. The detection sheet ensures reliable rotational movement of the rotary encoder during detection, while the actual continuous sheet is processed separately. This mediator resolves the contradiction by providing consistent detection conditions regardless of the actual sheet's friction characteristics or surface irregularities.
2Productivity
If the conveyance speed detection is performed during printing, then the detection can be done in real-time, but waste of continuous sheet and toner occurs due to non-print conveyance required for detection
Solution Approach 1:
Conveyance speed detection is performed in advance before actual printing begins. The detection sheet is fed through the system and detected during a preliminary phase, allowing the system to determine whether normal detection is possible before committing resources to printing. This preliminary action eliminates waste by identifying detection issues before toner and sheet are consumed in the printing process.
3Productivity
If feedback control is performed without verifying detectability, then the control system operates continuously, but print failure occurs when conveyance speed cannot be detected normally
Solution Approach 1:
The system performs a preliminary detectability verification using the detection sheet before initiating feedback control with the actual continuous sheet. This preliminary check determines whether the contact sensor can reliably detect conveyance speed under current conditions. Only after successful verification does the system proceed to printing and feedback control, ensuring reliable operation while maintaining continuous productivity.
Solution Approach 2:
The detection sheet serves as a cushioning measure that prevents potential print failures by identifying detection capability issues before actual printing begins. By preparing and testing the detection system in advance with a reliable detection sheet, the system cushions against future failures that would occur if detection were attempted directly with the actual continuous sheet under uncertain conditions.
Data Source
AI summary
An image forming apparatus according to the present invention includes a first conveyance member, a second conveyance member, and a controller. The first conveyance member and the second conveyance member convey a continuous sheet. The controller determines whether a second conveyance speed which is a conveyance speed of the continuous sheet conveyed by the first conveyance member and the second conveyance member can be detected normally on the basis of a first conveyance speed which is a conveyance speed of the continuous sheet conveyed by the first conveyance member.