Sheet feeder mechanisms, such as automatic document feeders (ADFs), are often incorporated into electronic devices such as copy machines, fax machines, scanners, and other such devices. Certain sheet feeder mechanisms also have a sheet separation mechanism, which is disposed adjacent the sheet feeder mechanism. The sheet separation mechanism separates a stack of sheets during feeding, such that the sheet feeder mechanism can feed the sheets one after another.
The sheet separation mechanism quickly wears out from use. A worn separation mechanism causes higher jam rates, misfeeds, and other functional errors. Unfortunately, a user is generally unaware of the need for a replacement sheet separation mechanism, such that the operational problems continue. This can result in time-consuming service calls, down time of the electronic device, and customer dissatisfaction.
Advantages of one or more disclosed embodiments may become apparent upon reading the following detailed description and upon reference to the drawings in which:
As discussed in detail below with respect to embodiments of the present invention, wear items, such as sheet feeders and sheet separators, provide a user with a notification to replace the wear item. For example, the wear item may have multiple layers of different colors, which provide a visual indication of a wear condition upon wear from one layer to another. Alternatively, the wear item may have conductive and non-conductive layers coupled to circuitry, which circuitry provides an electronic signal of a wear condition to the user upon wear from one layer to another. Although these multi-layer notification mechanisms are applicable to a variety of wear items, the following discussion is directed toward sheet feeders and sheet separators in electronic devices, such as scanners, fax machines, copy machines, printers and so forth. Also, while other aspects of sheet feed mechanisms exist, for ease of illustration, sheet feed rollers and sheet feed separation pads will be used as examples without limitation.
Turning now to the figures,
In the illustrated embodiment, the separation pad 20 and roller 22 cooperatively separate individual sheets from a stack and, also, feed the individual sheets through the sheet feeder 10. For example,
More specifically regarding operation, the representative sheet feeder 10 operates such that a user may place a sheet stack 28, such as a stack of documents, on the sheet launch area 12 of the sheet feeder 10 to begin the sheet feeding process. In the illustrated embodiment, the sheet launch area 12 is sloped downward toward the feed mechanism 18, allowing for a slight bias of the sheet stack 28 toward the sheet feed port 16. Additionally, a user may simply push one end of the sheet stack 28 within the sheet feed port 16. Accordingly, in operation, one end of the sheet stack 28 is adjacent the feed mechanism 18.
The feed mechanism 18 functions to draw sheets from the sheet stack 28 through the sheet feeder 10, one at a time. In operation, the motorized roller 22 contacts and draws the sheet 28A into the feed mechanism 18. During this feeding, the separation pad 20 frictionally slides along a bottom side of the sheet 28A to prevent feeding of additional sheets into the feed mechanism 18 from the sheet stack 28. For example, in the illustrated embodiment, the roller 22 contacts at least a portion of the separation pad 20, such that the roller 22 creates a motive force and the separation pad 20 creates a frictional force opposite the motive force. The motorized roller 22 then rotates against the single sheet 28A on the top of the sheet stack 28, such that the motive force draws the sheet 28A through the sheet feeder 10. Unfortunately, the motion of the sheet 28 into the sheet feeder 10 also may draw additional sheets from the sheet stack 28. In the illustrated embodiment, the sheet separation occurs at the interface between the separation pad 20 and the roller 22. As the motorized roller 22 draws the sheet 28A, the separation pad 20 frictionally slides along a bottom side of the sheet 28A, such that the frictional force catches and retains any additional sheets moving with the sheet 28A.
Other embodiments may have one or more rollers 22, in parallel and/or opposing one another, that exert a motive force on the sheet stack 28 to draw sheets from the sheet stack 28 through the feed mechanism 18 one after another. In various embodiments roller 22 and/or separation pad 20 are comprised of rubber, plastic, a material with a raised surface, a material with adhesive deposited thereon, or other high friction materials.
Due to the contact and friction between the separation pad 20, the roller 22, and the sheets 28, the separation pad 20 and roller 22 slowly wear with use of the sheet feeder 10. Therefore, the separation pad 20 and the roller 22 are both wear items. In other words, the forces imposed on the respective surfaces of the separation pad 20 and roller 22 typically cause surface wear and material loss, which eventually leads to functional problems with the feed mechanism 18. These two wear items 20 and 22 are referred to singularly and cumulatively, herein, as separation apparatus 30.
The continued use of worn separation apparatuses 30 can result in malfunction. One example of such malfunction is multifeeding, which occurs when multiple sheets are drawn into the feed mechanism. Another example of malfunction is misfeeding, which is the failure to draw sheets into the feed mechanism. Accordingly, to prevent malfunction, it is desirable to provide a means of informing a user of the need to replace the separation apparatuses 30. Present embodiments utilize multiple layers to assist a user in determining when replacement is necessary.
In other embodiments, outer layers 20A and 22A and inner layers 20B and 22B are composed of different materials. For example, the outer layers 20A and 22A may comprise an electrically conductive material, while the inner layers 20B and 22B comprise a nonconductive material, or vice versa. In one embodiment, a switch, sensor, or other circuitry may be coupled to the separation apparatuses 30, such that wearing through the outer layers 20A and 22A to the inner layers 20B and 22B triggers a switch, generates a signal, and/or changes the state of a circuit (e.g. open to close, or vice versa). Thus, in this embodiment, wearing away of the outer layers 20A and 22A provides electrical indication of the need to replace the separation apparatuses 30. This electrical indication may then trigger a hardware- or software-based indicator, such as an indicator light 32, which functions to inform a user of the pending need to replace at least one of the separation apparatuses 30. The electrical signal or circuit switching also may trigger a message or a display, such as a liquid crystal display (LCD), a remote monitor, a computer screen, and so forth.
The separation apparatuses 30 described above can be manufactured by various different methods, such as molding or extrusion. For example, one manufacturing method, as illustrated in
After manufacture, the separation apparatus 30 may be provided separately as replacement parts or as part of a complete package. In fact, in one manufacturing process embodiment, the separation apparatus 30 is inserted into a sheet feeder 10, which is incorporated into a copy machine, a fax machine, a scanner, printer, or another sheet-fed device.
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