Electrophotography – Image formation – Fixing
Reexamination Certificate
2000-12-21
2002-08-06
Chen, Sophia S. (Department: 2852)
Electrophotography
Image formation
Fixing
Reexamination Certificate
active
06430385
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a wick roller assembly for use in the fuser section of a electrophotographic copier/printer apparatus and in one of its aspects relates to an assembly for mounting the wick roller in the fuser section of an electrophotographic apparatus which allows the wick roller to be easily and quickly serviced and/or replaced from outside the fuser section housing.
BACKGROUND OF THE INVENTION
In a typical electrophotographic machine (e.g. copier, duplicators, printers, etc.), a continuous loop of photoconductor film is commonly used to transfer an image from an input section onto a receiving medium (e.g. a sheet of paper). The film is initially charged and then passes through an input section where an image (i.e. analog or digital) is projected onto the charged film. The film then moves through a developing section where a toner is applied to the charged image, and on through an image transfer section where the image is transferred to the sheet of paper or other medium. The paper is subsequently passed through a fuser section where the toner forming the image is fixed to the paper by elevated temperature and pressure. This is typically accomplished by passing the paper between two, opposed rollers, i.e. a pressure roller and a fuser roller, one of which is heated.
A known problem in fuser sections of this type is the that of “offset” which results when some of the heat-softened toner particles adhere to surface of the fuser roller and are not transferred to the paper or other medium as desired. As well understood in the art, this toner offset can severely affect the quality of the copies being made by the machine. One known method for alleviating this problem is to apply a silicone or the like release fluid or oil (hereinafter referred to a “release oil”) onto the fuser roller to prevent the toner from sticking thereto.
To apply this release oil onto the fuser roller, it is common to use a rotating wick, i.e. “wick roller”. A typical wick roller is comprised of a cylindrical core which is covered with a layer of a high temperature wicking material (e.g. a fabric such as porous felt or the like) which, in turn, is permeated with the release oil. The wick roller is mounted on movable brackets within the fuser section substantially parallel to the fuser roller and is moved into and out of contact therewith by a cam shaft or the like so that the release oil is applied to the fuser roller at timed intervals during the copying operation.
As release oil is used from the wick material, it must be replenished in order to sustain the operational life of the fuser section. Typically, this oil is supplied through a thin conduit having openings along its length through which the oil is distributed evenly within the wicking layer. This conduit is rigid enough to support its own weight within the wick roller and is attached to a oil supply tube which supplies the release oil to the perforated conduit within the wick roller. While the replenishing of the release oil to the wick roller significantly extends the service life of the wick roller, the wick roller will, nevertheless, eventually become dirty and/or worn-out and will have to be replaced.
Unfortunately however, since the wick roller is mounted inside the fuser section and is secured in place by a plurality of screws or the like which sometimes are hard to access, it is difficult and time consuming for a service technician to remove and replace this roller. Further, the natural inclination of a technician is to grasp and use the oil supply conduit to pull the wick roller out of its brackets which, in turn, is likely to cause the tube to bend, thereby requiring replacement of the tube. As will be recognized, this substantially adds to the time and the cost involved in servicing the wick roller.
As will be appreciated by those who depend on electrophotographic machine(s) in their commercial operations, time is normally of the essence. Therefore, it is imperative that downtime of the machine be kept to a minimum and that all maintenance/service operations be performed in as short of time as possible. Further, to keep maintenance/service costs down, the more frequently required maintenance operations should be capable of being carried out by a single service person with a minimum of special tools, if any. In some cases, if the maintenance/service operations are simple enough, the owner or user of the machine may train an employee to carry out such operations without requiring the services of an outside contractor.
Accordingly, it is desirable to provide ready access to the wick roller so that it can easily and quickly be removed and replaced within the fuser housing by a single technician thereby keeping service costs and downtime for the machine to a minimum.
SUMMARY OF THE INVENTION
The present invention provides an electrophotographic apparatus and a method for servicing. The apparatus includes a wick roller assembly which forms a part of the fuser section of the apparatus. Basically, the wick roller assembly is rotatably mounted in the housing of the fuser section and is releasably latched thereto whereby the fuser roller in the assembly can be quickly and easily accessed for servicing. This eliminates the need for a technician to remove the entire wick roller assembly in order to service or replace the wick roller, itself.
More specifically, the present invention relates to an electrophotographic apparatus having a fuser section which, in turn, includes a wick roller assembly. The frame of wick roller assembly is connected to the housing of the fuser section by a pivot connection so that the wick roller assembly can be rotated outward from the housing without removing said the roller assembly from the housing. This pivot connection is formed by a plurality of spaced tabs extending from the bottom of the frame which are received into a plurality of spaced slots which are formed across the bottom of said housing.
A releasable latch mechanism is provided on the frame of the wick roller assembly for securing the wick roller assembly in its operable position within said housing. The latch mechanism is comprised of an elongated bar which is slidably mounted on the frame of the wick roller assembly. The bar has a pair of keyhole-shaped openings therein, one near either end thereof. The keyhole-shaped openings are adapted to receive a respective one latch pin which, in turn, is at a respective side of the housing of the fuser section. A handle is rotatably mounted on the frame for moving said bar laterally whereby the slotted portion of a keyhole-shaped opening moves behind the head of a respective latch pin to latch the frame of the wick roller assembly to the housing of the fuser section.
A handle is provided on the frame to move the latch bar between the latched and said unlatched positions. A lock element is passed through the frame and is threaded into said housing to secure the frame to the housing to prevent unintentional rotation of the frame with respect to the housing. A removable cover is releasably secured over the wick roller assembly when the wick roller assembly is in said latched position within said housing to protect the assembly and to further prevent the unintentionally unlatching of same.
From the above, it can be seen that the wick roller within the wick roller assembly can quickly and easily be serviced by removing the cover, unlatching the wick roller assembly from the housing of the fuser section, and then rotating the assembly away from the housing without having to remove the entire wick roller assembly. This exposes the wick roller which is resting between two open brackets within the frame of the assembly from which the wick roller can be easily removed. The wick roller can be then serviced and/or replaced into the brackets within the wick roller assembly. The assembly is then rotating back towards the housing and the latch mechanism is then returned to its latched position.
REFERENCES:
patent: 4501483 (1985-02-01), Romansky et al.
patent: 4899197 (1990-02-01), Davis
Cahill David F.
Hanselman James F.
Morganti Terry N.
Chen Sophia S.
Heidelberger Druckmaschinen
Tran Hoan
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