Cutting State Detection in Image Forming Apparatus
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Solution Overview
Problem
Existing technologies cannot determine whether a recording sheet has been cut normally or if there are abnormalities in the cutting process, leading to potential issues where inadequately cut sheets are discharged.
Innovation Solution
An image forming apparatus is equipped with a cutter having first and second blades, a moving device, and a signal output device that monitors the variation in moving load during cutting. The controller analyzes these signals to determine the state of the sheet medium among normal, first abnormal, and second abnormal states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only the presence of sheet medium between blades is detected, then sheet jam detection is possible, but cutting quality cannot be determined
Solution Approach 1:
The cutting process is segmented into multiple detection phases: initial sheet presence detection, cutting force monitoring, and post-cutting verification. By dividing the detection into separate stages with different methods, the system achieves both reliable sheet jam detection and precise cutting quality assessment without conflating the two functions.
Solution Approach 2:
A signal output device is introduced as an intermediary component that captures cutting process data (such as motor current, vibration, or sound) and transmits it to the controller. This intermediary enables indirect measurement of cutting quality without interfering with the actual cutting operation, resolving the contradiction between detection reliability and measurement precision.
2Productivity
If sheet medium is discharged without verification, then productivity is maintained, but cutting quality cannot be ensured
Solution Approach 1:
The system performs preliminary cutting verification before sheet discharge by analyzing cutting force patterns or signal characteristics during the cutting process. If the verification passes, the sheet is immediately discharged, maintaining productivity. If it fails, corrective actions are taken before discharge, ensuring cutting quality without creating bottlenecks.
Solution Approach 2:
A feedback mechanism continuously monitors cutting parameters and compares them against predetermined thresholds. The controller receives real-time feedback from the signal output device and adjusts the discharge decision accordingly. This closed-loop feedback system ensures that cutting quality verification does not significantly delay productivity, as most normal cuts are quickly verified and discharged.
3Measurement precision
If multiple cutting states are distinguished, then cutting abnormality detection is improved, but system complexity increases
Solution Approach 1:
The detection system uses dynamic threshold adjustment based on the phase of cutting operation. Different cutting states (normal cutting, sheet jam, incomplete cut) are identified by analyzing the temporal dynamics of cutting force or signal characteristics rather than using fixed thresholds. This dynamic approach enables multiple state discrimination with relatively simple hardware, reducing system complexity while maintaining high measurement precision.
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
The solution allows for accurate determination of the sheet medium's state, preventing inadequately cut sheets from being discharged and enabling appropriate corrective actions based on the identified cutting abnormalities.
Implementation Method 1
a signal output device that outputs a signal indicating a variation over time in a value correlated with a moving load for the at least one blade in cutting the sheet medium
Data Source
AI summary
An image forming apparatus includes a conveyor to convey a sheet medium, a print engine to form an image on the sheet medium, a cutter to cut the sheet medium, a signal output device, and a controller. The cutter includes a first blade, a second blade, and a moving device to move at least one of the first and second blades. The controller receives, from the signal output device, a signal indicating a variation over time in a value correlated with a moving load for the at least one blade, and determines, based on the received signal, which state the sheet medium is in among a plurality of states including a first state where the sheet medium is cut normally, a second state where there is an abnormality in cutting the sheet medium, and a third state where there is a different abnormality in cutting the sheet medium.