Printer Pickup Roller Control for Sheet Transport Reliability
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Solution Overview
Problem
In continuous transport mode, printers face issues where sheets longer than the transport distance from the pickup roller to the print section are unintentionally drawn out or printing is interrupted due to the simultaneous operation of the pickup, relay, and transport rollers using a single motor, leading to restrictions on sheet length and transport distance.
Innovation Solution
A printer configuration with a common actuator driving the pickup, relay, and transport rollers, controlled by a control section that stops the driving force transfer to the pickup roller after the last sheet is drawn out, allowing continuous transport of all sheets regardless of length, and includes a measuring section with a sensor to detect sheet edges for precise positioning and process switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pickup roller, relay roller, and transport roller are rotated simultaneously using one motor in continuous transport mode, then manufacturing costs are reduced, but sheets longer than the transport distance are unintentionally drawn out or printing is interrupted
Solution Approach 1:
The patent applies dynamics by making the driving force transfer dynamic rather than static. The control section dynamically adjusts whether the common actuator transfers driving force to the pickup roller based on real-time sheet position detection. When the rear edge of the current sheet is detected near the print section, the system dynamically switches to stop transferring force to the pickup roller, preventing unwanted drawing out of subsequent sheets. This dynamic control resolves the contradiction by maintaining reliable sheet transport while using a single motor.
Solution Approach 2:
The patent implements feedback through the sensor that detects the position of sheet edges. The detection section provides continuous feedback about sheet position to the control section, which then adjusts the driving force transfer accordingly. This feedback mechanism enables the system to respond to actual sheet positions and prevent both the drawing out of unused sheets and interruption of printing, while still utilizing a single common actuator for cost efficiency.
2Reliability
If the pickup roller is stopped when the rear edge of the nth sheet reaches the print section, then printing reliability is improved, but continuous transport is interrupted between sheets
Solution Approach 1:
The system dynamically controls the driving force transfer based on sheet position. Instead of a static stop-start approach, the control section continuously monitors sheet position via the sensor and dynamically adjusts the pickup roller's engagement with sheets. This allows the system to maintain continuous transport for sheets that need printing while selectively disengaging from sheets that have completed printing, thus maintaining both reliability and productivity.
Solution Approach 2:
The system takes preliminary action by detecting the rear edge position of sheets in advance. When the sensor detects that the rear edge of the current sheet is approaching the print section, the control section proactively stops transferring driving force to the pickup roller before the sheet fully enters the printing zone. This preliminary action prevents printing interruptions while maintaining continuous transport flow.
3Reliability
If a lower limit for sheet length is provided to prevent drawing out unused sheets, then sheet transport reliability is improved, but sheet length flexibility is restricted
Solution Approach 1:
The patent eliminates the need for a fixed lower limit on sheet length by implementing dynamic control. The control section continuously monitors sheet position and adjusts driving force transfer in real-time. This dynamic approach allows the system to reliably transport sheets of any length, from short to long sheets, by adapting the pickup roller's engagement based on actual sheet position rather than relying on a predetermined minimum length constraint.
Solution Approach 2:
The system changes the control parameter from a static sheet length threshold to a dynamic position-based control. Instead of restricting sheet lengths below a certain threshold, the control section uses sensor feedback to monitor the actual position of sheet edges and adjusts the driving force transfer accordingly. This parameter change enables the system to handle sheets of varying lengths flexibly while maintaining transport reliability.
4Adaptability or versatility
If the sheet transport distance is lengthened to enable double-sided printing, then printing versatility is improved, but the risk of drawing out unused sheets increases
Solution Approach 1:
The sensor-based feedback system enables reliable control over extended transport distances. By continuously detecting sheet edge positions, the control section can accurately determine when sheets have reached the print section regardless of transport distance. This feedback mechanism allows the system to safely extend the transport path for double-sided printing while preventing the drawing out of unused sheets through precise, position-based control.
Solution Approach 2:
The system takes preliminary action by detecting sheet positions in advance along the extended transport path. When using a single common actuator, the control section proactively stops transferring driving force to the pickup roller when the rear edge of the current sheet is detected near the print section. This preliminary disengagement prevents the drawing out of subsequent sheets even when the transport distance is extended for double-sided printing operations.
Data Source
AI summary
A printer includes a media stacking section, a print section, a pickup roller, a relay roller, a common actuator, a transport mechanism section and a control section. The control section is configured to control the common actuator based on a print job and displacement of the printing media. The control section is configured to stop transferring of driving force of the common actuator from the pickup roller to an nth printing medium after the pickup roller draws out the nth printing medium and the relay roller starts to send out the nth printing medium which is drawn out in a case where a print job, where printing is carried out on n of the printing media with a length in a transport direction shorter than a transport distance of the printing media from the pickup roller to the print section, is processed in the continuous transport mode.