Card Conveyance Sensor Placement for Jam Reduction
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Solution Overview
Problem
Existing image forming apparatuses with direction changing sections face inefficiencies in determining whether the direction changing mechanism can rotate and in detecting multi-fed cards, leading to increased process time due to the need for the card to reach downstream sensors, which can result in errors and longer conveyance distances.
Innovation Solution
A medium conveying apparatus with a control section that uses multiple sensors to determine the presence and position of the card, allowing the direction changing section to change direction without requiring the card to reach downstream sensors, thereby shortening the process time and improving accuracy in detecting multi-fed cards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the card is conveyed to the downstream sensor to determine whether the reversing unit can rotate and whether multi-feeding occurs, then the determination accuracy is improved, but the process time increases
Solution Approach 1:
The patent applies preliminary action by using the upstream sensor Se1 to detect the card's presence and position before the card reaches the downstream sensor. The control unit determines whether the reversing unit can rotate and whether multi-feeding occurs based on the timing of sensor detections during the conveyance process, rather than waiting for the card to reach the downstream sensor. This preliminary determination shortens the process time while maintaining accuracy.
Solution Approach 2:
The patent uses feedback from the upstream sensor Se1 to continuously monitor the card's conveyance status. The control unit receives feedback signals from sensor Se1 at different time points (when the front end and rear end of the card pass the sensor) and uses this feedback to calculate the card conveyance distance and determine the reversing unit's rotatability and multi-feeding status, eliminating the need to wait for downstream sensor detection.
2Measurement precision
If the card conveyance distance is detected from the time when sensor Se1 detects the front end of the card to the time when sensor Se1 detects the rear end of the card, then the multi-feeding detection accuracy is improved, but the card must be conveyed further increasing process time
Solution Approach 1:
The patent performs the multi-feeding detection action preliminarily by using the upstream sensor Se1 to detect both the front end and rear end of the card during its conveyance. The control unit calculates the card conveyance distance based on the time interval between these two detections and compares it with the standard card length, enabling multi-feeding detection before the card reaches the downstream sensor area.
Solution Approach 2:
The upstream sensor Se1 acts as an intermediary that provides sufficient information for both card presence detection and multi-feeding detection. By monitoring the card's passage through sensor Se1 and calculating the conveyance distance, the system uses this intermediate measurement to infer multi-feeding status without requiring additional downstream sensor detection.
Data Source
AI summary
Disclosed herein is a medium conveying apparatus in which the time for unjamming can be shortened. The medium conveying apparatus includes rollers configured to convey a card Ca, a rotary unit F provided in a medium conveyance path and configured to hold and rotate the card Ca, a sensor SN26 arranged downstream the rotary unit F on the medium conveyance path and, and a control section. The control section controls a first card-conveyance motor for driving the rollers to convey the card Ca into the rotary unit F, and determines whether the sensor SN26 detects the card Ca. The sensor SN26 is arranged at the same distance as a sensor SN3 or a shorter distance than the sensor SN3, from the rotary unit F.