CRU Roller Spacer Prevents Flat Spots
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Solution Overview
Problem
During storage and shipping, the retard and feed rolls in a sheet feeding nip assembly of electrostatographic machines can develop undesirable deformations such as tread lines and flat spots, leading to premature failure and operational noise when assembled.
Innovation Solution
A customer replaceable unit (CRU) assembly with a spacer and anti-mounting assembly, featuring a removable cam member that temporarily spaces the rollers apart to prevent contact and deformation, ensuring proper geometry and operation upon installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the retard roll and feed roll are assembled in contact with each other in the CRU during storage and shipping, then the CRU is ready for immediate operation, but tread lines and flat spots are formed on the rollers leading to premature failure and operational noise
Solution Approach 1:
A spacer assembly is pre-installed in the CRU frame during manufacturing to maintain roller separation. This preliminary protective action prevents flat spot formation during storage and shipping, and the spacer is designed to be easily removed by the end user just before installation into the copier, ensuring rollers are protected during transit but ready for operation upon user activation.
2Manufacturing precision
If the rollers are kept in contact to maintain proper sheet handling nip geometry, then proper sheet feeding function is achieved, but deformation and flat spotting occur during storage and shipping
Solution Approach 1:
A spacer assembly acts as an intermediary element positioned between the retard roll and feed roll. This spacer maintains the correct geometric relationship and spacing between rollers while preventing direct contact that would cause deformation. The spacer is designed with features that allow it to be easily removed by the end user before installation into the copier, at which point the rollers engage to form the proper sheet handling nip.
3Loss of time
If the CRU is assembled with rollers in contact for immediate use, then installation time is reduced, but roller flat spots and noise occur during operation
Solution Approach 1:
The spacer assembly is designed as a temporary, disposable component that is easily removed by the end user. It serves its protective function during storage and shipping, then is discarded (removed) before installation into the copier. This allows the CRU to be shipped in a protected state without requiring complex permanent separation mechanisms, minimizing both installation time and preventing operational noise from flat-spotted rollers.
Data Source
AI summary
A customer replaceable unit (CRU) assembly for mounting in a sheet handling machine is disclosed and includes (a) a CRU frame having a frame size for fitting into a mounting portion within the sheet handling machine; (b) a first roller assembled rotatably to the CRU frame; (c) a second roller assembled rotatably to the CRU frame and for resilient contact with the first roller to form a sheet handling nip; and (d) a spacer and anti-mounting assembly including (i) a holding feature formed in the CRU frame and (ii) a removable member mounted in the holding feature for temporarily preventing mounting of the CRU frame into the mounting portion within the sheet handling machine, and for temporarily spacing the second roller out of resilient contact with the first roller so as to prevent roller flat spots, operating roller noise, and premature roller failure.