Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
1999-10-22
2001-02-13
Braun, Fred L (Department: 2852)
Electrophotography
Image formation
Photoconductive member
Reexamination Certificate
active
06188858
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application entitled ROLLER DRIVING APPARATUS OF PRINTER earlier filed in the Korean Industrial Property Office on the 22
nd
day of Oct. 1998 and there duly assigned Serial No. 44353/1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a driving mechanism for rotating a roller closely contacting a photo-receptor web in a printer, and, more particularly, to a roller driving mechanism and process for transferring rotational power between the roller and a motor in an image formation apparatus.
2. Description of the Related Art
Various types of structures connecting a gear to a roller to feed a photo-receptor web are used in printers. A common design for image formation equipment such as a printer or a photocopier for printing images and characters onto printable paper uses a photo-receptor web supported by and wound around a pair of rollers, a laser scanning unit that forms electrostatic latent images or characters on the surface of the photo-receptor web, and a developing unit that forms toner images corresponding to the electrostatic latent images on the photo-receptor web. The toner images formed on the photo-receptor web are transferred to printable paper stock via a transfer roller while the photo-receptor web passes between set of rollers. Typically, gears transfer rotational power from a motor to the rollers. We have found that conventional structures for connecting the gear to the roller are not suitable to transfer the rotating power to the roller precisely. If a load is applied to the roller, the gear can not rotate the roller precisely because the load applied to the roller causes the structure between the roller and the gear to prevent the gear from transferring the rotating power to the roller precisely.
We have noticed that it is not easy during assembly or during subsequent operation of the roller driving apparatus to precisely perform the installation and the engagement of thread portions which are formed on first and second clutch members and which face each other. Moreover, it takes too much time for assembly, maintenance and repair of the roller driving apparatus since the entire structures are complicated. Furthermore, the first and second clutch members and neither engage each other precisely nor rotate integrally, thereby the rotating force of the motor is not accurately transferred to the roller because one clutch member retreats from the other clutch member when a load is applied to the roller. The rotating power transferred from motor to one of the clutch members and the load transferred from supporting shaft to the other of the clutch member causes the two clutch members to retreat from each other against the elastic force of the spring. Therefore, one of the clutch members slips from the other clutch member, and the rotational force of the motor is not accurately transferred to the roller. Therefore, constant-speed rotation of the roller and constant speed circulation of the photo-receptor are not achieved. The level of quality in the printing operation is lowered. In our opinion, this design for the roller driving mechanism for rotating the rollers that contact and circulate the photo-receptor web is neither suitable to transfer the rotating force from the motor to the rollers nor adequate to assemble and maintain the clutch members to contact each other precisely.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved roller deriving apparatus for precisely transferring a rotating force from motor to a roller.
It is another object to provide a roller deriving apparatus able to accurately rotate the roller.
It is an yet another object to provide an apparatus for preventing the gear transmitting the rotating force to the roller from slipping from the roller.
It is still another object to provide an apparatus for allowing the gear to precisely engage the roller.
It is still yet object to provide an apparatus able to form an electrostatic image and a toner image on a photo-receptor web.
It is further object to provide an apparatus able to fix a toner image of the photo-receptor web on a sheet of paper.
It is also an object to provide an apparatus for obtaining constant speed rotation of the roller.
It is also an object to provide an apparatus for preventing relative rotating movement between a roller and a gear during transferring of the rotating power.
These and other objects may be achieved by providing a roller driving apparatus in a printer including a support shaft coaxially fixed to the roller, a coupling groove formed on an outer circumferential surface in a radial direction, a rotation member receiving a rotating force from a motor through a connecting gear and driving gear and having a shaft coupling hole accommodating the support shaft, a coupling member inserted into a receiving hole formed on the rotation member to be capable of moving in a direction of the axis of the center of the receiving hole, and a spring elastically and radially biasing the coupling member in a direction to protrude from the inner circumferential surface of the rotation member. The coupling member protrudes and retreats with respect to an inner circumferential surface of the rotation member and is inserted into the groove of the support shaft when protruding from the inner circumferential surface of the rotation member without moving relatively and slipping coaxially between the rotation member and roller.
REFERENCES:
patent: 4046473 (1977-09-01), Trainer
patent: 5132728 (1992-07-01), Suzaki et al.
patent: 5937241 (1999-08-01), Kumar et al.
patent: 6011942 (2000-01-01), Taniguchi et al.
patent: 6032008 (2000-02-01), Kolodziej
Pang Jeong-hun
Swapceinski John P.
Braun Fred L
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
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