Patent Application
20110081179
This invention relates to an electrophotographic marking system and, more specifically, to a toner waste collection assembly.
Illustrated and disclosed is a co-pending application (Attorney Docket No. ID 20090682) owned by the present assignee is an application relating to a gate having rotating blades that is positioned above a toner collection bag and that conveys waste toner to the collection bag. This present application, ID 20090682Q and an application on ID 20090682 are being filed on the same date. The disclosure of ID 20090682 is totally incorporated by reference into the present disclosure.
In a typical electrophotographic printing process, a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charge therein in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed at a developer station by bringing a developer material into contact therewith. Generally, the developer material is made from toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. Heat is applied to the toner particles to permanently affix the powder image to the copy sheet. Often, residual toner remains in the developer station and the cleaning station. This residual toner is generally passed to a toner waste dispensing assembly or container where it is passed outside the marking system.
This excess or residual toner is eliminated from the machine and waste toner is collected in a waste toner container. The waste toner container is then removed when filled and disposed of. In color systems waste toner cannot be reused because of the plurality of colored toner in the waste mix.
Some xerographic or electrophotographic machines exhaust waste dry ink (toner) at a rate of approximately 320 grams/hour (actual rate varies with job area coverage, stock size, toner aging purge parameters and manifold emissions). At this rate, a currently-used waste dry ink container has to be replaced approximately every 28 hours. Furthermore, the waste container has stringent strength requirements: sustain 6 inches wg vacuum pressure and hold 20 lb. weight.
Because of the high waste rate and stringent strength requirements, a very expensive plastic container is currently used in several machines. The high replacement rate leads to about 35 tons of plastic waste per year per machine. The disposal of these plastic containers poses an environmental problem in the prior art.
Designing a simpler waste cyclone dispense system would make the electrophotographic marking apparatus a greener machine by reducing plastic waste in the landfill. It would also reduce the piece part cost of a high replacement item.
This invention proposes an alternative to eliminate the continued vacuum pressure requirement on the current waste dry ink container. Using a hard, thick plastic container will no longer be necessary. By using a controller that turns off the vacuum when the controlled gate is opened and the collecting bag is being removed. The necessity of a rigid-strong pressure resistant plastic collection container of the prior art is avoided. In one embodiment, the gate will be motor driven to open the gate and shut it once every hour or at set periods of time. Software is provided in the controller to open and close the gate every time the marking system boots up. In place of this expensive plastic collection container, a substantially less expensive collection, environmentally friendly, disposable bag can be used. The cyclone separators in the system no longer apply a continuous 6 inch wg vacuum pressure on the bag waste container of this invention since the controller turns the vacuum pressure off at set intervals. This invention proposes the use of a controlled gate to assist the collection in a bag and not require the waste container suction of the cyclone separators. The vacuum pressure is only maintained in the collection assembly before the controlled gate begins to convey the waste via the bag opening. This feature will be described in detail in the drawings of this disclosure.
This invention provides a toner collection assembly to replace the rigid and expensive waste collection containers of the prior art. The requirements of high fill rate and mass and internal vacuum in the prior art lead to frequent replacement of a thick plastic container. In the present invention, a waste assembly is provided that eliminates the requirement to sustain a continuous vacuum by using a controlled gate that acts at atmospheric pressure. This allows an inexpensive thin-walled, disposable container or bag to be used. This invention provides a cheaper, flimsier bag container that can be used when used without any vacuum pressure. Toner would be allowed to pile up above the gate, and then it would drop into the container when the pressure is turned off and the controlled gate is periodically opened.
While the collection container will be described herein as a “bag”, other inexpensive collection containers may be used, if suitable, such as degradable boxes or other degradable paper or plastic collectors. These are included in the term “bag” as used in this disclosure. The bags used are in one embodiment similar to bags used in vacuum cleaners. The collection system or assembly of this invention is particularly well suited for color multiple station marking systems but obviously can also be used in monochromatic marking systems.
The collection bag of the present invention can easily be retrofitted into those existing toner waste collection stations presently being used. It is important that the bags used be UL approved or have similar private or governmental approval and acceptance. Any other suitable controlled gates or toner conveyors may be used to deposit waste toner in the bag provided they can replace the thick plastic collection container and can eliminate the system vacuum as the controlled gate is opened.
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In developer station 21 and in cleaning station 28 where excess toner occurs, waste housing 30 accumulates waste toner and other debris and transports it via collection tubes 31 to the waste collector 32 of this invention. While
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In summary, this invention provides a novel toner waste collection assembly and a novel electrophotographic marking system. The electrophotographic marking system comprises a developer station and a cleaning station and these stations comprise a waste toner dispensing unit. The dispensing unit comprises collection tubes that are configured to convey waste toner to a waste collection assembly. This assembly comprises a funnel portion that is configured to feed waste toner to a controlled drop gate that is configured to transport the waste toner to a disposable and decomposable collection bag.
The controlled gate comprises a hinged drop blade that is controlled by a controller and motor to open and close. The marking system comprises a plurality of xerographic structures each having at least one of the collection tubes.
In one embodiment, the system is a color marking system comprising a plurality of color stations; each station comprises at least one collection tube.
In another embodiment, the system is a monochromatic marking system with at least one collection tube. The waste collection assembly is configured to be easily retrofitted into existing electrophotographic marking systems.
The controlled gate of this invention is configured to transport waste toner into a collection bag while the pressure in the collection assembly is turned off by the controller thereby preventing any pressure existing in an adjacent waste collection assembly from entering the collection bag. This is done by turning the pressure off when the gate is open. The toner waste collection assembly of this invention comprises a controller and collection tubes running from an electrophotographic marking system to a toner collection funnel in the assembly. The toner collecting funnel connects the collection tubes to a controlled drop gate. This gate is configured to transport waste toner to a replaceable decomposable collection bag. The controlled, hinged drop gate is fitted below the funnel and is configured when opened or dropped to prevent any assembly pressure from entering the bag because the pressure is automatically turned off by the controller when the gate is open and conveys toner waste into the bag. The collection bag is located on and above a weight scale. This scale is configured to indicate via a sensor when the bag is filled with waste and needs to be replaced. The bag has an opening that is configured to accept waste toner transported by the controlled drop gate.
The waste collection assembly is configured to transport waste toner into a collection bag while at the same time maintaining only atmospheric pressure in the bag. As above noted, the weight scale is positioned immediately below the bag and is configured to indicate the weight of the bag and the toner waste in the bag. A motor shown in
It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
