Printer Sheet Detection Between Discharge Rollers and Cutter
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Solution Overview
Problem
Existing image forming devices fail to accurately detect sheets around the cutter, leading to potential inaccuracies in cutting and handling.
Innovation Solution
The device includes sensors to detect the presence of sheets between discharge rollers and a cutter, with a controller managing the cutting process based on sensor inputs, and adjusts driving amounts and speeds to ensure precise cutting, even accounting for sheet shrinkage due to heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sheet detection unit is placed in the conveying path to detect sheets for cutting, then the cutting process can be controlled, but the detection accuracy around the cutter position is insufficient
Solution Approach 1:
A reflective member is introduced as an intermediary between the light source and the sheet. The reflective member reflects light from the light source toward the sheet, and the light reflected from the sheet is detected by the light receiving unit. This intermediary arrangement enables accurate detection of the sheet's presence and position around the cutter without requiring direct line-of-sight detection, thereby improving measurement precision while maintaining manageable device complexity
Solution Approach 2:
The patent replaces mechanical sheet detection methods with an optical detection system consisting of a light source, reflective member, and light receiving unit. This substitution allows for non-contact, high-precision detection of the sheet's position and presence around the cutter, significantly improving measurement accuracy compared to mechanical sensors
2Manufacturing precision
If the sheet is conveyed to the cutter position for cutting, then the cutting operation can be performed, but sheet shrinkage due to heat from the fixing unit causes inaccurate cutting position
Solution Approach 1:
The optical detection system provides real-time feedback on the sheet's position and dimensions after it passes through the fixing unit. The light source and light receiving unit detect the actual sheet position, and this information is fed back to the control unit, which adjusts the cutting position accordingly to compensate for any shrinkage or dimensional changes caused by heat from the fixing unit, thereby maintaining cutting position accuracy
Solution Approach 2:
The optical detection system performs preliminary measurement of the sheet's position and dimensions after it exits the fixing unit but before cutting. This preliminary detection allows the system to anticipate and compensate for heat-induced shrinkage by adjusting the cutting position in advance, ensuring accurate cutting despite the harmful thermal effects
3Measurement precision
If multiple sensors are added to detect sheets around the cutter, then detection accuracy improves, but device complexity and cost increase
Solution Approach 1:
The optical detection system serves multiple functions: it detects the sheet's presence, determines the sheet's position, and measures the sheet's dimensions after fixing. This single multi-functional system replaces what would otherwise require multiple separate sensors, achieving high detection accuracy while avoiding the complexity and cost increases associated with adding multiple individual sensors
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
Accurate detection and cutting of sheets are achieved, reducing the risk of jams and improving user notification of errors, while maintaining efficiency and cost-effectiveness.
Implementation Method 1
a light source configured to emit light toward the sheet; a light receiving unit configured to receive light reflected from the sheet
Implementation Method 2
a heating rotor; and a pressure rotor in which a nip is formed between the heating rotor and the pressure rotor
Implementation Method 3
fix an image formed on the sheet onto the sheet
Data Source
Figure 1
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AI summary
The present invention provides a technology that makes it possible to accurately detect a sheet around a cutter. Provided is a printer 1 characterized by comprising: a device main body 2 that has a conveyance route 201 for a sheet S; a heating roller 61; a fixing device 6 that fixes, on the sheet S, an image formed on the sheet S; first discharge rollers 85 that are positioned downstream of the fixing device 6 and convey the sheet S; second discharge rollers 86 that are positioned downstream of the first discharge rollers 85 in the conveyance direction and that discharge, to the outside of the device main body 2, the sheet S conveyed by the first discharge rollers 85; a cutter 10 that is positioned at the cutter position B located between the first discharge rollers 85 and the second discharge rollers 86 in the conveyance direction and that can cut the sheet S in the cutting direction crossing the conveyance direction; and a sheet detection sensor SE4 that detects whether or not the sheet S is present at the first detection position between the first discharge rollers 85 and the second discharge rollers 86 in the conveyance direction.