Electrophotography – Internal machine environment – Particle or contaminant control
Reexamination Certificate
2001-12-20
2003-12-16
Pendegrass, Joan (Department: 2852)
Electrophotography
Internal machine environment
Particle or contaminant control
C399S263000
Reexamination Certificate
active
06665505
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to commonly-assigned U.S. patent application No. D/A1155Q, filed concurrently herewith, entitled INTERNAL AGITATING MECHANISM FOR AGITATING MATERIALS WITHIN SEALED CONTAINERS, by Litwiller.
BACKGROUND OF THE INVENTION
This invention relates to the packaging and subsequent removal of dry marking materials that tend to clump or bridge when shipped or stored in containers. Dry marking materials such as electrophotographic toners are packaged and shipped in particulate form and other dry marking materials such as dry ink jet waxy solids may be shipped in pelletized or granulated form. Such dry marking materials typically settle and become more densely packed over time. A frequent consequence of such dense packing is often the formation of clumps and bridges formed of the materials within the containers. Agitating and/or aerating the materials before use can restore the desired density, consistency and flow characteristics. The present invention deals with a novel apparatus and method for providing in situ agitation and aeration within a dry marking material cartridge. This apparatus and method obviates the need for human intervention such as shaking or tapping a container, thereby making the degree and type of agitation more reliable.
Although various dry marking materials are contemplated for use with the present invention, the invention will be described in relation to sealed containers that transport and load electrophotographic toners. Other dry marking materials that may benefit from the present invention include, without limitation, waxy colorants, solid ink jet colorants, ionographic inks, and any other dry ink-like product that ships in a substantially non-liquid form.
Generally, in the process of electrostatographic printing, a photoconductive insulating member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive insulating layer is thereafter exposed to a light image of an original document to reproduced. This records an electrostatic latent image on the photoconductive member corresponding to the information areas contained within the original document. Alternatively, in a printing application, the electrostatic latent image may be created electronically by exposure of the charged photoconductive layer by an electronically controlled laser beam or light emitting diodes. After recording the electrostatic latent image on the photoconductive member, the latent image is developed by bringing a developer material charged of opposite polarity into contact therewith. In such processes the developer material may comprise a mixture of carrier particles and toner particles or toner particles alone (both these single component and dual component development systems shall hereinafter be called “toner”). Toner particles are attracted to the electrostatic latent image to form a toner powder image that is subsequently transferred to copy sheet and thereafter permanently affixed to copy sheet by fusing.
In such a printing machines, the toner material is consumed in a development process and must be periodically replaced within the development system in order to sustain continuous operation of the machine. Various techniques have been used in the past to replenish the toner supply. Initially, new toner material was added directly from supply bottles or containers by pouring to the developer station located within the body of the automatic reproducing machine. The addition of such gross amounts of toner material altered the triboelectric relationship between the toner and the carrier in the developer station, thereby resulting in reduced charging efficiency of the individual toner particles and accordingly a reduction of the development efficiency when developing the electrostatographic latent image on the image bearing surface. In addition, the pouring process was both wasteful and dirty in that some of the toner particles became airborne and would tend to migrate into the surrounding area and other parts of the machine. Accordingly, separate toner hoppers with a dispensing mechanism for adding the toner from the hopper to the developer station in the printing machines on a regular or as needed basis have been provided. In addition, it has become common practice to provide replenishment toner supplies in a sealed container that, when placed in the printing machine, can be automatically opened to dispense toner into the toner hopper. In some of these designs, the toner cartridge may itself serve as the toner hopper. After this type of toner cartridge is mated to the printing machine at an appropriate receptacle, mechanisms are inserted into the toner cartridge that serve to transport the toner from the toner cartridge into the developer station or an intermediate toner hopper on a regulated basis. See, U.S. Pat. No. 5,903,806 issued to Matsunka et al.; U.S. Pat. No. 5,678,121 issued to Meetze et al.; and U.S. Pat. No. 5,495,323 issued to Meetze.
In any design utilizing a customer replaceable toner cartridge for replenishment, one difficulty that arises is the uniform dispensing of the toner. In particular, toner particles are known to settle and clump during shipment and storage. This clumping phenomenon is caused for a variety of reasons: 1) particles of smaller size can fill and pack spaces between larger articles; 2) toner particles are often tacky; and 3) the electrostatic properties of toner particles enable charge attractions between particles. The result is often agglomerations, or clumps, of particles within the toner cartridge. These agglomerations often compact and form bridging structures within the toner cartridge, and such bridging structures adhere to the sides of the toner cartridges. Simple probes and augers as disclosed in patents such as U.S. Pat. No. 5,903,806 issued to Matsunka et al., U.S. Pat. No. 5,678,121 issued to Meetze et al., and U.S. Pat. No. 5,495,323 issued to Meetze may penetrate such agglomerations and bridging structures but do not break them up. Even rotation of the cartridges after mating onto a printing machine toner receptacle does not impart enough energy to shake the clumped toner particles apart from its various clumps and bridging structures. In the worst case, toner may be entirely prevented from exiting the cartridge unless it is agitated. Since toner cost is a major component of the total cost of printing, any significant amount of toner left in a toner cartridge significantly increases the effective cost of using the printer. Worse, customers that do not receive the expected print volume from a cartridge may assume that the cartridge is faulty and make a warranty claim. In other cases, such customers have been known to make a service call that consumes valuable service and technician time.
In response to the above problems related to removal of substantially all toner from toner cartridges, various devices and procedures have been developed. One effective procedure when performed correctly is simply the shaking of a toner cartridge by human operators prior to mating the cartridge with the printing machine receptacle. However, many operators do not read the instructions and do not know or remember that toner cartridges need to be shaken. In addition, even when human operators read instructions, humans inevitably interpret product instructions subjectively such that an instruction to “vigorously agitate” a cartridge may lead to too much force by a few operators and too little by others. The result is that some cartridges are shaken or pounded hard enough to be damaged while others are not shaken enough to break up clumps and bridges that may have formed. Once the cartridge is mated to the receiving receptacle while the toner particles remain clumped and bridged, the operator is left with several choices: One is to leave the cartridge as is and to risk failure of toner transfer from the cartridge, wasting toner and/or believing that the printing system is consuming too much toner. A second choice is removal of the ca
Litwiller Debora M.
Meetze, Jr. Murray O.
Pendegrass Joan
Spooner Richard F.
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