Electrophotography – Image formation – Development
Reexamination Certificate
2001-12-20
2003-10-14
Royer, William J. (Department: 2852)
Electrophotography
Image formation
Development
C399S263000
Reexamination Certificate
active
06633738
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the packaging and subsequent removal of material that tends to stick to the inside perimeter of containers and to thereby prevent viewing of the contents inside the containers. The invention is particularly applicable when such attachment of particles to the container sides is due primarily to electrostatic forces. Many particulate materials are packaged and shipped in plastic, glass, or similar smooth-sided containers. When human users dump or other-wise transfer particle contents from a nearly transparent shipping container, the common experience is a desire to see inside the container in order to see how much of the contents have been removed. If the intent is to remove all of the contents, then such viewing is to see whether all contents have been removed. However, if a thin layer of particles have attached themselves to the inside walls of the container, then such viewing is made difficult or impossible. The problem becomes more frustrating when the particulate matter is light-weight and, accordingly, difficult to determine by heft whether the contents have been dumped. Even more frustration occurs when the container is first fastened to a receiving receptacle before the contents are removed. Since the container is fastened in place, its heft cannot be easily determined. Although containers filled with other particulate or granulated products may benefit from the present invention, including without limitation, pelletized or granulating marking materials such as waxy inks, the invention will be explained in reference to electrophotographic toners, or other dry inks and marking materials. Typical electrophotographic toners are stored and transported in nearly transparent plastic bottles. The process of transferring toners from such toner bottles or cartridges occurs after the bottle has been affixed to a receiving receptacle The toner particles themselves are light and fluffy. Moreover, toner particles are designed to readily accept electrostatic charges. Hence, the agitation and shaking of toner bottles that is recommended prior to loading the cartridges onto printing machines typically induces charges in the particles that cause at least a thin film of particles to adhere to the inside walls of their containers. The combined result is that it is very difficult to determine whether all the contents of a toner bottle have been transferred from the toner bottle to the receiving receptacle of a printing system. Many user observations document users attempting to shake, tap, and otherwise agitate the bottle while it is fastened to the printing machine. Users also commonly attempt to peer into the battle. All these are attempts to ensure that the contents of the bottle have transferred. And for the reasons described above, most users who attempt such verification are unable to make the determination. Observations confirm persistent user frustration at not being able to visually or manually detect whether all toner particles have been transferred.
The following is a background description of the nature of electrostatic toners: Generally, in the process of electrostatographic printing, a photaconductive insulating member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive insulating member is thereafter exposed to a light image of an original document to be reproduced. This records an electrostatic latent image on the photoconductive insulating 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 insulating member by an electronically controlled laser beam or light emitting diodes. After recording the electrostatic latent image on the photoconductive insulating member, the electrostatic 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 a copy sheet and thereafter permanently affixed to the copy sheet by fusing.
In such 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 a developer station located within the body of an 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 an electrostatographic latent image on an 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 other designs, the toner cartridge is mated to the appropriate receptacle of the printing machine and then toner is dumped all at once from the toner cartridge into a toner hopper within the printing machine. Such toner in the hopper is then drawn into the developer station on a regulated basis. The toner cartridge, once its contents are dumped, is removed from the receiving receptacle and is either discarded or recycled.
In any design utilizing a customer replaceable toner cartridge for replenishment, one difficulty that arises is ensuring that all toner has been removed from the cartridge. This difficulty has two aspects: First, as described above, it is difficult to detect whether all toner has been removed from the cartridge. This is partly because toners in small quantities weigh little and are therefore difficult to detect by sensing their weight. More importantly, toner particles are designed to efficiently accept electrostatic charges with the result that they typically coat the inside surfaces of toner cartridges, thereby making the cartridges opaque.
The second difficulty in ensuring that all toners have been removed from a toner cartridge is the tendency of toner particles 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 particles: 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 co
Royer William J.
Spooner Rickard F.
Xerox Corporation
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