Printer Roller Load Control for Jam Detection
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Solution Overview
Problem
Existing printers face challenges in early detection of paper jams, which can lead to increased jam severity and reduced throughput due to incorrect detection of small jams and overcurrent issues from factors other than jams.
Innovation Solution
A printer system that utilizes a controller to manage the rotation of rollers based on motor load, using a PWM signal duty cycle to detect jams by measuring the load increase, and strategically suspending sheet feeding to prevent jam worsening without unnecessary operation halts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference value for overcurrent detection is reduced to detect small jams earlier, then early detection capability is improved, but false detection increases due to overcurrent from factors other than jams
Solution Approach 1:
The patent divides the roller system into two segments: a first roller that rotates during sheet feeding and a second roller that rotates during printing. By monitoring the driving source's load separately for each roller's operational phase, the system can distinguish between load increases caused by jams during sheet feeding versus load increases during printing, thereby reducing false detections while maintaining early jam detection capability
Solution Approach 2:
The patent dynamically adjusts the detection strategy based on the operational state of the rollers. The controller determines whether the first or second roller is rotating and applies different detection thresholds or monitoring approaches accordingly. This dynamic adaptation allows accurate detection of small jams during sheet feeding without triggering false alarms from normal printing operations
2Reliability
If sheet feeding is suspended immediately upon detecting a jam, then jam severity is reduced, but printer throughput decreases due to unnecessary operation halts
Solution Approach 1:
The patent implements dynamic control of sheet feeding suspension based on real-time roller rotation status. When a jam is detected during the printing phase (second roller rotating), the system continues sheet feeding without suspension. When a jam is detected during sheet feeding (first roller rotating), the system suspends feeding. This conditional, dynamic approach prevents unnecessary operation halts while still controlling jam severity when actually needed
Solution Approach 2:
The controller continuously monitors the driving source's load magnitude and roller rotation status, using this feedback to make intelligent decisions about sheet feeding suspension. The feedback loop allows the system to differentiate between genuine jams requiring intervention and normal operational variations, thereby avoiding unnecessary throughput reduction
Data Source
AI summary
A printer includes a casing, a print mechanism disposed inside the casing, and a paper tray. A conveying route extends from the tray to the print mechanism, with a first roller disposed adjacent the tray to feed a sheet from the tray to the conveying route. A second roller is disposed in the conveying route and conveys the sheet fed by the first roller to the print mechanism. A driving source provides a driving source to the first roller and the second roller. A controller is configured to, in response to a printing request, apply the driving force from the driving source to the first and second rollers such that the first and second rollers rotate. In response to a magnitude of a load of the driving source, the controller applies the driving force to the second roller such that the second roller rotates, and the controller does not apply the driving source to the first roller such that the first roller does not rotate.