Sheet Edge Alignment in Image Recording Apparatus
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Solution Overview
Problem
Image recording apparatuses face challenges in accurately aligning the edge of large-size sheets during the reversal process due to pulling forces between the transporting and reversal roller pairs, leading to slippage and non-uniformity in the edge-alignment operation.
Innovation Solution
The apparatus includes a second transmission mechanism with a sun gear, pendulum gear, and gear row that changes posture to transmit rotations to the re-transporting roller pair, allowing for increased rotation of the transporting motor to compensate for sheet size and orientation, ensuring proper edge-alignment by adjusting the transportation amount based on whether the sheet is sandwiched by the roller pairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor rotation is switched to reverse the sheet in the second transporting path, then the sheet can be transported in the opposite orientation, but the pendulum gear mechanism requires switching time during which driving force becomes temporarily not transmittable to the re-transporting roller pair
Solution Approach 1:
The control unit increases the rotation amount of the transporting motor in advance before the motor rotation is switched. This preliminary action ensures that the sheet has sufficient transportation distance to reach the recording start position even during the time when the pendulum gear mechanism is switching and driving force is not transmittable to the re-transporting roller pair.
2Reliability
If the transporting roller pair and reversal roller pair sandwich the sheet to be reversed, then the sheet can be securely held during reversal, but pulling at the sheet against each other between the roller pairs causes slippage in the transporting roller pair
Solution Approach 1:
The control unit changes the rotation amount parameter of the transporting motor based on whether the sheet is sandwiched between the transporting roller pair and reversal roller pair. When the sheet is sandwiched, the rotation amount is increased to compensate for the pulling forces and prevent slippage, thereby maintaining edge-alignment precision despite the conflicting forces on the sheet.
3Manufacturing precision
If the rotation amount of the transporting motor is increased to compensate for sheet size and orientation, then accurate edge-alignment can be achieved, but the mechanism complexity increases
Solution Approach 1:
The control unit uses feedback from sensors that detect whether the sheet is sandwiched between the roller pairs and the sheet size information to dynamically adjust the rotation amount of the transporting motor. This feedback mechanism enables accurate edge-alignment while keeping the control logic systematic and manageable rather than overly complex.
Data Source
AI summary
There is provided an image recording apparatus including: a main body with first and second transporting paths, a transporting roller pair, a recording portion, a reversal roller pair, a re-transporting roller pair, a transporting motor, first and second transmission mechanisms, and a controller. The second transmission mechanism has: a sun gear, an arm, a pendulum gear, and a gear row. The second transmission mechanism is configured to change a posture between a first posture and a second posture. The controller is configured to determine a position of the sheet, determine a size of the sheet, switch the rotation of the transporting motor under certain conditions, and increase the rotation amount of the transporting motor more for the case that the size of the sheet is determined to be not less than a transport distance than for the case that it is determined to be less than the transport distance.