U-Shaped Sheet Path for Curl Prevention in Duplex Printers
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Solution Overview
Problem
Conventional image recording apparatuses face challenges in preventing curling of recording sheets, which leads to increased size and complexity, making it difficult to correct the sheet shape without additional components or upsizing the apparatus.
Innovation Solution
An image recording apparatus with a U-shaped sheet-supply path and a controller that controls the sheet-supply roller to stop the recording sheet in a deformed U-shape state, allowing for smooth transfer and preventing floating, thus correcting the sheet shape without additional components or upsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a flat lower guide plate is disposed downstream of the recording head to prevent curling, then the recording sheet curling is reduced, but the image recording apparatus is upsized
Solution Approach 1:
The patent introduces a U-shaped sheet supply path that utilizes the vertical dimension and spatial arrangement to naturally guide and flatten the recording sheet through its path, rather than relying on a large flat guide plate extending downstream. The U-shape configuration allows the sheet to be guided through a compact three-dimensional space, achieving flattening without increasing the linear downstream length of the apparatus.
2Stability of the object's composition
If sheet-transfer rollers and spur rollers are mounted to sandwich and hold the recording sheet, then the recording sheet is prevented from curling, but the construction of the interior is complicated
Solution Approach 1:
The patent extracts and eliminates the need for complex roller sandwiching mechanisms by utilizing the U-shaped path geometry itself to guide and control the recording sheet. The path configuration naturally provides the necessary guidance and flattening function without requiring additional active roller components to sandwich and hold the sheet, thereby simplifying the interior construction.
3Device complexity
If the recording sheet is stopped in a deformed U-shape state in the sheet-supply path, then the sheet shape is corrected without additional components, but the transfer timing control becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-deforming the recording sheet into a U-shape as it enters the sheet supply path, and then controlling the sheet supply roller to stop the sheet at a specific position where the U-shape deformation naturally occurs. This preliminary deformation and controlled stopping allow the sheet to be properly positioned and flattened without requiring additional correction components during the recording process, simplifying the overall device while managing control timing.
Data Source
AI summary
An image recording apparatus configured to record images on front and back surfaces of a sheet, including: a head which ejects ink onto the sheet for recording; a sheet-supply roller which contacts the sheet so as to transfer the sheet for supplying to the head; a sheet-supply path which is provided between the sheet-supply roller and the head, which has a U-shape, and through which the sheet is transferred such that one of surfaces thereof opposite to the other of the surfaces contacted by the sheet-supply roller faces the head; and a sheet-stopping control section configured to control the sheet-supply roller such that the sheet transferred by the sheet-supply roller is stopped for a first time in the sheet-supply path in a state in which the sheet is deformed so as to have a U-shape, after an image has been recorded on the front surface of the sheet and before an image is recorded on the back surface thereof.