Image Recording Apparatus Sheet Conveyance Accuracy
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Solution Overview
Problem
The accuracy of image recording on a sheet-formed medium is compromised due to variations in the conveyance amount, leading to potential increases in the time required to complete image recording, as the paired conveyer rollers push the sheet forward when the rear end passes through the nipping position, causing inaccuracies in the predetermined conveyance amount.
Innovation Solution
An image recording apparatus is designed with a system that includes sheet sensors to accurately detect the rear end of the sheet, allowing for a corrected conveyance amount to be calculated by adjusting the conveyance amount based on the distance between detection and nipping positions, thereby preventing the sheet from being pushed forward prematurely and ensuring accurate timing for image recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conveyance amount is increased to reduce recording time, then productivity improves, but the sheet is pushed forward by the conveyer rollers causing manufacturing precision to deteriorate
Solution Approach 1:
The system performs preliminary detection of the sheet's rear end position using a sensor before the sheet reaches the conveyer rollers. Based on this advance detection, the controller calculates the optimal conveyance amount that accounts for the pushing force effect, and initiates the conveyance action at the precisely timed moment when the rear end is at the detected position. This preliminary detection and calculation enables the system to pre-compensate for the pushing force, allowing larger conveyance amounts to be used without sacrificing accuracy.
Solution Approach 2:
The system establishes a feedback loop where the sensor continuously detects the sheet's rear end position, and this detection information is fed back to the controller. The controller uses this feedback to dynamically calculate and adjust the conveyance amount for each line, taking into account the actual position and the expected pushing force effect. This closed-loop feedback mechanism ensures that even with larger conveyance amounts, the sheet is always conveyed by the correct adjusted amount, maintaining manufacturing precision while improving productivity.
2Manufacturing precision
If the conveyance amount is decreased to maintain precision, then manufacturing precision is preserved, but the length of time for image recording increases
Solution Approach 1:
The system dynamically changes the conveyance amount parameter based on the detected position of the sheet's rear end. Instead of using a fixed small conveyance amount, the controller calculates an optimized conveyance amount that is larger than the conventional value but is precisely adjusted according to the actual sheet position and the predicted pushing force effect. This parameter change allows the system to use larger conveyance amounts (reducing recording time) while maintaining precision through the calculated correction.
3Measurement precision
If a sensor is positioned upstream to detect the rear end accurately, then measurement precision improves, but the distance between detection and nipping positions increases requiring smaller conveyance amounts
Solution Approach 1:
The sensor is positioned upstream from the conveyer rollers to perform preliminary detection of the sheet's rear end position. This advance detection allows the controller to calculate the optimal conveyance amount before the sheet reaches the rollers, taking into account the distance and the pushing force effect. The preliminary action of detection and calculation enables the system to compensate for the longer distance, allowing larger conveyance amounts to be used despite the increased sensor-to-roller distance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents the length of time for image recording from increasing and maintains accuracy by ensuring the sheet is conveyed by the correct amount, reducing the impact of the conveyer rollers' pushing force on the recording process.
Implementation Method 1
One of the paired conveyer rollers may be urged against the other of the paired conveyer rollers. Therefore, when a rear end of the sheet, i.e., an upstream end in the conveying direction, passes through a position between the paired conveyer rollers, the paired conveyer rollers may move closer relatively to each other.
Data Source
AI summary
An image recording apparatus, having a conveyer including a pair of conveyer rollers, a recorder, a first sensor, and a controller, is provided. The controller, after a part of an image is recorded on a sheet-formed medium, within a period between a point before the first sensor detects an upstream end of the sheet-formed medium and a point after the first sensor detects the upstream end of the sheet-formed medium, controls the conveyer to convey the sheet-formed medium in a plurality of segmented actions, corrects a conveyance amount to convey the sheet-formed medium after the first sensor detects the upstream end of the sheet-formed medium to a third conveyance amount, which is smaller than the conveyance amount, and after the sheet-formed medium is conveyed by the third conveyance amount, controls the recorder to record another part of the image on the sheet-formed medium.