Patent Application
20080061493
Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings. In the drawings, like reference numerals refer to like parts throughout the various figures unless otherwise specified.
For a better understanding of the present invention, reference will be made to the following Detailed Description, which is to be read in association with the accompanying drawings, wherein:
This application is directed to document feeders and methods of making and using the document feeders. The application is also directed to document feeders with a separator arrangement utilizing a gas flow for at least partially separating documents, and methods of making and using the document feeders.
A document feeder can use a flow of gas, such as air, to separate at least a portion of the top document from those documents underneath to provide a more reliable mechanism for separation of the documents for individual feeding. For example, the document feeder can use the Coanda effect to direct a portion of the gas flow along a convex surface and underneath at least a portion of the top document to separate that document from those beneath it and direct the document towards a feed belt.
The Coanda effect, also known as the “boundary layer attachment effect” or “the wall-attachment effect,” is the tendency of a steam of fluid (gas or liquid) to flow along a convex surface in contact with the fluid rather than in a straight line. Although the invention is not bound to any particular theory, it is thought that as the fluid moves across the convex surface a certain amount of friction occurs between the fluid and the surface which tends to slow the fluid. This resistance to flow of the fluid can pull the fluid toward the surface.
The use of the Coanda effect (e.g., the flow of a gas along a convex surface) can allow the gas outlet to be placed at a level below the top document so that the separator arrangement providing the gas flow is not in the document path. The gas flow separates or “fluffs” the top document from those below it.
To further facilitate single document feed, the document feeder may also lift at least the leading edge of a feed belt of the document feeder upon receiving the top document. This action moves the feed belt further away from the remaining documents. Once the top document has been fed into the next stage or device, the document feeder is returned to its original position for feeding the next document.
The document feeder can be a stand-alone device or can be incorporated into, or otherwise coupled or attached to, another device, such as a printer, copier, fax machine, collator, scanner, sorter, and the like. The document feeder can, for example, feed documents one-at-a-time to the next stage of larger apparatus. The document feeder may receive documents, for example, from another portion or stage of the apparatus (or a different apparatus), or documents can be provided by a user (e.g., stacked in a tray or other holding arrangement) for feeding.
The drive system can include, for example, a drive motor 162 (
The document feeder 100 is designed to remove the top document 118 from a stack of documents 116. The term “document” can refer to, for example, a sheet of any material (such as a sheet of paper, a sheet of labels, a transparency, and the like) as well as envelopes, magazines, booklets, and the like. It will be recognized that the term “document” is not limited to items that contain textual or graphical information. The document may be blank (e.g., a blank sheet of paper.)
Specific implementations of the document feeder 100 can be designed for particular applications and for use with a particular range of documents. This range could be specified using one or more document parameters such as, for example, document size, weight, porosity, caliper, texture, and so forth. Preferably, the document feeder 100 is capable of selecting only the top document 118 from the stack of documents 116 over the entire parameter range expected for the particular application or indicated for use with the document feeder 100.
The feed belt 102 is formed using any suitable material including, but not limited to, cloth or any other fabric, plastic, or rubber. As illustrated in
The feed belt 102 is rotated by the drive system which, in at least some embodiments, includes drive rollers 104, at least one of which is attached to a drive motor 162 (
The vacuum plenum 106 can be made using any suitable material including plastic or metal or any combination thereof. The vacuum plenum 106 typically includes one or move vacuum ports 122 and one or more openings 124. A variety of different arrangements can be used to connect the vacuum port(s) with the opening(s). The vacuum port(s) 122 are coupled to a vacuum generator 164 (
The separator 110 (preferably utilizing the Coanda effect) can be coupled by a conduit 120 to a gas flow generator 166 (
The flow 128 of gas is directed along the convex surface 112, preferably using the Coanda effect, toward an edge of the documents 118, 116. This gas flow lifts at least one edge of the top document 118 (and possibly other documents) and separates at least a portion of the top document 118 from the remainder of the documents. The gas flow 128 also preferably directs the top document 118 toward the feed belt 102 where it can be attached using the vacuum system. The use of the Coanda effect can allow the separator 110 to be placed below the level of the top document 118, as illustrated in
The flow rate of the gas, the curvature of the convex surface, and the weight, porosity, and size of the document are factors in the ability of the gas flow to separate top document from those documents beneath it. As one example, a 10-15 psi (about 69,000 to 105,000 N) flow can be used with a convex surface having a ¼ to ⅜ inch (about 0.6 to 1 cm) radius.
The flow rate of the gas and the curvature of the convex surface can be selected to obtain a level of separation for the top document. In one example, about 10 documents are separated from each other, with the gap between documents progressively increasing towards the top of the stack.
Preferably, for any specific implementation of the document feeder 100 the gas flow 128 provided by the separator 110 is sufficient to separate the heaviest document expected for use with that implementation. In some embodiments, the gas flow may be constant and fixed. In other embodiments, the gas flow may be alterable or variable. For example, in some embodiments, a user may be requested to designate a document parameter (e.g., weight) range so that the gas flow can be adjusted accordingly. In other embodiments, there can be an automatic sensing apparatus to select the gas flow based on the documents to be fed.
As one example of operation of the document feeder 100, a gas flow is established through the separator 110 and along the convex surface 112 to separate (e.g., “fluff”) at least one edge of the top document 118 from the remainder of the documents 116. A vacuum is established through the vacuum ports 122 and openings 124 of the vacuum plenum 106 so that the top document 118 is held by the feed belt 102. The feed belt 102 is rotated using the drive rollers 104 and drive motor 162 to feed the top document 118 to the next stage or to another machine. It will be recognized that the vacuum may be established prior to, during, or after establishment of the gas flow and that rotation of the feed belt can begin prior to, during, or after establishment of the vacuum and gas flow.
The document feeding process can be performed continuously; feeding one document after another. The document feeding process can also be performed intermittently; feeding one document and then waiting until commanded to feed the next document, or feeding a series of documents and then waiting. During operation, the gas flow and vacuum may be continuously provided and the feed belt may be continuously rotated. Alternatively, one or more of the gas flow, vacuum, and feed belt may be operated in a non-continuous manner. For intermittent operation, it is more likely that one or more of the gas flow, vacuum, and feed belt will be operated in a non-continuous manner.
It will also be recognized that a document feeder can include one or more feed belts 102. When multiple feed belts are used, the feed belts can be spaced apart from one another to interact with different portions of the document. With multiple feed belts, one or more device components, such as one or more of the drive rollers 104, vacuum plenum 106, separator 110, or convex surface 112, can be extended between multiple feed belts. Alternatively, any of these components can be provided separately for each feed belt (or any subcombination of feed belts.) For example, preferably, but not necessarily, each of the feed belts will be operated using the same drive motor.
In the particular embodiment of
A variety of methods can be used to activate the lifting mechanism and raise the feed belt. In one embodiment, a sensor can be used to detect when a document has been attached to the feed belt. The sensor then activates the lifting mechanism (such as a piston or lift motor) to begin raising the feed belt 102.
As another example, in the illustrated embodiment of
One embodiment of the document feeder also includes a photo sensor (not shown) that is triggered when a document is attached to the feed belt or when the feed belt is lifted. The photo sensor can actuate the drive motor to begin rotating the feed belt. Optionally, the drive motor can be halted when the document is fed, as detected by the photo sensor or by release of the piston 138. In one embodiment, the top document is fed by the document feeder into a pair of pressure rollers that are running at a faster speed than the feed belt.
A variety of different vacuum plenums can be used. The vacuum plenum 106 in the particular illustrated embodiment of
As indicated above, the document feeder can be operated continuously or intermittently. One example of operation includes attaching the top document 118 to the feed belt 102 using the vacuum system and separator arrangement as described above. This causes the vacuum in the lift actuator 134 to increase raising at least the leading edge of the feed belt 102. Optionally, as the feed belt is raised, a photo sensor is triggered which starts the drive motor and feeds the document. When the document leaves the feed belt 102, the opening 124a is exposed and the vacuum in the lift actuator 134 drops which results in the feed belt returning to its original position. Optionally, this movement triggers the photo sensor and turns off the drive motor. The document feeder is then ready to feed the next document.
The above specification, examples and data provide a description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention also resides in the claims hereinafter appended.
