Image Formation Device Sheet Cutting Nip Distance
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Solution Overview
Problem
In image forming apparatuses with a cutter, sheets are often heated and pressurized more than necessary at the nip portion of the fixing unit when the sheet conveyance stops before the entire sheet has passed through the nip portion, leading to inefficient cutting.
Innovation Solution
The image forming apparatus includes a configuration where the cutter is positioned downstream of the fixing unit, allowing the sheet to be cut at a center position, and the conveying distance from the nip portion to the cutter is set to be larger than half of the sheet's dimension in the conveying direction, ensuring the entire sheet has passed through the nip portion before cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the cutter is positioned close to the fixing unit for compact design, then device complexity is reduced, but the sheet cannot fully pass through the nip portion before cutting causing excessive heating and pressurization
Solution Approach 1:
The patent increases the distance parameter in the conveying direction between the nip portion and cutter, transforming a compact longitudinal arrangement into an extended linear configuration. This dimensional change allows the sheet to fully pass through the nip portion before cutting, eliminating excessive thermal and mechanical effects while maintaining overall apparatus compactness through optimized spatial arrangement.
2Object-affected harmful factors
If the conveying distance from nip portion to cutter is increased to allow complete sheet passage, then harmful thermal and mechanical effects are reduced, but the apparatus length increases
Solution Approach 1:
The patent positions the cutter at a predetermined distance downstream from the nip portion, establishing the complete sheet passage condition in advance before cutting operation begins. This preliminary spatial arrangement ensures that the entire sheet has passed through the heating and pressurization zone before the cutter activates, preventing partial sheet exposure to excessive thermal and mechanical effects.
3Manufacturing precision
If the sheet is cut while conveyance is stopped for precision cutting, then manufacturing precision is improved, but the sheet may be stuck between rollers if not fully conveyed
Solution Approach 1:
The patent ensures complete sheet conveyance through the nip portion before initiating the cutting operation. By pre-positioning the sheet fully past the heating and pressurization zone and stopping conveyance only after complete passage, the system achieves precise cutting alignment while preventing sheet entrapment between rollers, thus maintaining both cutting accuracy and conveyance reliability.
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 configuration allows for efficient cutting of sheets in a state where the entire sheet has passed through the nip portion, preventing unnecessary heating and pressurization, and ensuring accurate cutting without positional deviation.
Implementation Method 1
a toner image formed by image formation is heated and pressurized at a nip portion of a fixing unit and is fixed
Implementation Method 2
The cutter is capable of cutting the sheet S into two portions
Data Source
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AI summary
The present invention cuts a sheet in a state in which the sheet has passed through a nip part in its entirety. An image formation device 1 comprises a device body 2, an image formation unit, a fixing device 6, and a cutter 7. The image formation unit forms an image on a sheet. The fixing device 6 has a heating rotor 61 and a pressurizing rotor 62 that forms a nip part NP with the heating rotor 61, and fixes the image on the sheet S. The cutter 7 is disposed on the downstream side of the fixing device 6 in the conveying direction of the sheet S, and can cut the sheet S. The cutter 7 can cut the sheet S to be cut at a central position P of the sheet S in the conveying direction. A distance D1 by which the sheet S is conveyed from the nip part NP to the cutter 7 is larger than half a dimension LS of the sheet S in the conveying direction (D1 > LS/2)