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US 5,294,967 AGranted
Image forming apparatus with a plurity of adjustable developing units
AssigneeCanon Kabushiki Kaisha
InventorsAtsushi Munakata, Masahiro Itoh, Akira Watanabe, Yuji Sakemi
Life of this patent
Estimating the term…
Abstract
A developing apparatus having a supporting frame for supporting plural developing units. The supporting frame is movable to present a selected one of the developing units to a development operating position. The supporting frame is provided with positioning members for positioning the developing units. The positioning members are fixed on the movable frame in the manner that the position of the positioning member is adjustable. Each of the developing units is faced to an image bearing member at the operating position without contact to the image bearing member.
Claims12
An image forming apparatus, comprising:
- an image bearing member;
- latent image forming means for forming an electrostatic latent image on said image bearing member;
- and
- developing means for developing the latent image, said developing means including;
- a plurality of developing units for supplying to said image bearing member developers of different colors, each of said developing units including a container for containing one of the developers and a developer carrying roller for carrying the developer from said container to a developing position, said developer carrying roller having a shaft portion at an end thereof;
- supporting means for supporting said plurality of developing units and movable along a predetermined path to present a selected one of said developing units to an operating position for developing the latent image, said supporting means including a movable supporting frame movable along the path, a plurality of positioning members fixed on said movable supporting frame, each of said positioning members having an engaging portion for engaging the shaft portion of the developer carrying roller of a respective developing unit, and adjusting means for adjusting positions where said positioning members are fixed on said supporting frame, wherein the shaft portion of each of said developer carrying rollers is engaged to and positioned by a respective one of said positioning members, whereby each of said developing units is disposed in facing relationship with said image bearing member at the operating position without contact with said image bearing member, and whereby each of said developer carrying rollers is disposed in facing relationship with said image bearing member at the developing position with a predetermined distance therebetween for supplying the developer to the image bearing member to develop the latent image.
3 more elements
An image forming apparatus, comprising:
- an image bearing member;
- latent image forming means for forming an electrostatic latent image on said image bearing member;
- developing means for developing the latent image, said developing means including:
- a plurality of developing units for supplying to said image bearing member developers of different colors, each of said developing units including a container for containing one of the developers containing toner particles and magnetic carrier particles mixed together, a non-magnetic developer carrying sleeve for carrying the developer from the container to a developing position, said sleeve having a shaft portion at an end thereof, and a magnet disposed within said developer carrying sleeve;
- supporting means for supporting said plurality of developing units and movable along a predetermined path to present a selected one of said developing units to an operating position for developing the latent image, said supporting means including a movable supporting frame movable along the path, a plurality of positioning members fixed on said movable supporting frame, each of said positioning members having an engaging portion for engaging the shaft portion of the developer carrying roller of a respective developing unit, and adjusting means for adjusting positions where said positioning members are fixed on said supporting frame, wherein the shaft portion of each developer carrying sleeve is engaged to and positioned by a respective one of said positioning members, whereby each of said developing units is disposed in facing relationship with said image bearing member at the operating position without contact with said image bearing member, and whereby each said developer carrying sleeve is disposed in facing relationship with said image bearing member at the developing position with a predetermined distance therebetween for supplying the developer to the image bearing member to develop the latent image;
- and
- a voltage source for applying an alternating bias voltage to the developer carrying sleeve of the developing unit placed at the operating position to form an alternating electric field in the developing position;
- wherein a relative volumetric ratio Q (%) of the magnetic carrier particles at the developing position satisfy in each of the developing units
- 25.ltoreq.Q.ltoreq.40.
6 more elements
Dependencies are inferred from the claim text.