Lens barrel


PURPOSE: To effectively prevent the infiltration of dust into a closed space by providing an air inlet/outlet port for communicating the space ad the outside on the wall in the closed space and mounting a filter in the air inlet/outlet port. CONSTITUTION: The air inlet/outlet port is provided on the wall of the closed space 17 which is changed in volume by two relatively moving cylindrical bodies and the filter 10 for removing dust is provided in this air inlet/outlet port 8A. When a 3rd group lens unit 6 is moved forward at the time of, for example, a zoom operation, the volume of the closed space 11 behind this lens unit 6 increases and, therefore, the pressure in the space 7 drops and the exterior air is sucked through the air inlet/outlet port 8A into the space 17 but since the air filter 10 is loaded in the air inlet/outlet port 8A, the dust intruding into the inflow air in the space 17 is removed by the filter 10. The inflow of the dust into the space 17 and the lens barrel is prevented in this way. COPYRIGHT: (C)1991,JPO&Japio




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    US-7719776-B2May 18, 2010Ricoh Company, LimitedLens unit, lens barrel, optical device, scanner, and image forming apparatus