Patent Application
20050006836
The present invention relates, in general, to media handling devices, and, more specifically, to media duplexers.
Media technology has advanced considerably over the last 20 years. One popular feature, found in printing systems is duplex or double-sided printing. Similar features may also be found in scanning devices. Duplex printing or scanning uses a mechanism that can physically turn the substrate or print media over. Once turned over, an image may be placed onto or scanned from the other side of the substrate. A method of accomplishing this task is to divert the substrate down an opening, alley, or slot and then pulling the sheet back out of the slot wherein the former trailing edge is now the leading edge. Typically, a subsequent page waits until the preceding page has completely exited this apparatus before entering. In order to implement this process, a gap or space between successive pieces of paper larger than the length of a page is designed into the duplex system. This page-sized gap generally reduces the performance of the system by half.
Image fragility typically prevents more than one page to be in the media duplexer at any one time. Accordingly, the aforementioned gap between successive pages is generally, at least, page-sized. In printing processes, image fragility includes issues such as smudging, ink transfer, sheet collisions, static build up, and the like. If two pages were in contact while sliding by each other, print quality would likely suffer due to transfer of ink from one page to the other, smudging the images on either page, having the pages collide, or building up enough static energy to either cause a spark within the printer, potentially damaging it or creating attraction forces on the paper that make it difficult to handle.
Representative embodiments of the present invention are directed to a duplexer for a media handling system, the duplexer comprising a sheet barrier suspended between upper and lower rotation points, wherein the sheet barrier comprises a belt having at least one barrier separated by at least one opening, and wherein the sheet barrier rotates about upper and lower rotation points, and retractable pinch rollers disposed at an entry to the duplexer, wherein the retractable pinch rollers retract when one of the at least one barrier is rotated near the entry to the duplexer, wherein media enters the duplexer through one of the at least one opening.
Additional representative embodiments of the present invention are directed to a method for accommodating two pages in a duplexer at the same time, the duplexer having a rotating barrier disposed therein, the rotating barrier having barrier material separated by an open gap, the method comprising pushing a current page into an exit path from the duplexer through one of the open gaps, directing a next page into an input path, rotating the barrier material between the next page entering the duplexer and the current page exiting the duplexer, wherein the one of the open gaps is positioned to allow the current page to exit the duplexer, pulling the current page completely from the duplexer, and rotating another of the open gaps into a position opening the exit path to the next page.
Further representative embodiments of the present invention are directed to a system for a changing media orientation in a media handling system, the system having a revolving obstructer disposed therein, the revolving obstructer having at least one opening therein, the system comprising means for directing a media page within the system to an exit path through one of the at least one opening, means for rotating the barrier material between a next page entering the system and the current page exiting the system, wherein one of the at least one opening is positioned to allow the current page to exit the system, means for pulling the current page completely from the system, and means for rotating the at least one opening into a position exposing the exit path to the next page.
A barrier is disclosed that protects a page of media leaving a duplexer from being damaged or smeared by a subsequent page entering the duplexer at the same time. Additionally, or alternatively, the barrier protects the subsequent page. The barrier is in the form of a belt or sheet which may comprise a smooth film, or other such element, which, by virtue of its geometry and motion, repeatedly presents itself between the entering and exiting pages or media when contact between those pages would otherwise be inevitable. The coexistence of media in the duplexer enables increased performance over mechanisms that must increase page to page gaps to avoid collisions. This feature allows the gap between successive pages to be less than one page length, allowing better system performance. Successive pages may coexist in a duplexing slot without colliding with, smearing, or otherwise threatening the image quality of each other.
It should be noted that such a duplexer may be used within a printer, a scanner, a fax, or other kind of printing or multifunction device. The present invention is not limited to solely a printer.
Tracks 100 and upper and lower belt pulleys 101 and 102 may comprise a tractor drive as illustrated in
The elements shown in
When a page of media begins to enter the duplexer, it first encounters the material of either of sheets 103 and 104, which forms a barrier between the entering page and an exiting page. The entering page continues downward and soon encounters one of openings 105, through which it enters. Before the page has reached the bottom of the duplexer, the other one of sheets 103 and 104 begins to rise up along the backside of the page. This segment of belt material of either of sheets 103 and 104 will then protect the page from the next entering page.
The belt material may be chosen to interact favorably with the imaging agent, without causing smearing. Such a material may include a film of polyamide, a textile/fabric, or even some form or polymer or rubber. The material may be selected to have anti-static properties as well as a characteristic that would inhibit ink from adhering to the surface to cause smearing or streaking. Additionally, the material selected for sheet barrier 10 in certain embodiments of the invention provides a flexible belt or sheet that is still stiff enough to hold itself rigid across its width. The width would preferably be great enough to allow the windows or openings 105 in sheet barrier 10 to be wider than the widest-allowed print media.
The length of sheet barrier 10 may be set at any various number of lengths responsive to several criteria that should be considered for proper operation. A first consideration is that sheet barrier 10 should generally reach retractable pinch roller 21 (
Still another length consideration may be that sheet barrier 10 should generally be long enough so that the leading edge of the entering sheet does not touch the exiting sheet. Furthermore, sheet barrier 10 should generally be long enough such that the longest compatible substrate may be held by retractable pinch roller 21 at its furthest reach into the duplexer without the free end of the substrate touching lower pulley system 102.
In addition to width and length considerations, the speed of sheet barrier 10 is an element that should generally be considered. Sheet barrier 10, which typically rotates upward toward the input side of the duplexer to “scoop up” incoming sheets, should generally rotate at a speed such that sheets 103 and 104 and/or openings 105 generally reaches the same position in a cyclic pattern. The length of the frequency pattern should generally be equivalent with the cycle of the substrates entering and leaving the duplexer. Speed considerations may generally be influenced by the size and number of sheets and/or the size and number of openings. Furthermore, sheet barrier 10 should generally not be so fast that it creates an undesirable aerodynamic effect on either of the entering or exiting substrates.
In order to accommodate transportation of the paper or media after its trailing edge has left the pinch rollers of the entering path and before the same edge (now the leading edge) has entered the first pinch rollers of the exiting path, a set of otherwise retracted pinch rollers near the top of the duplexer (retractable pinch rollers 21 of
Although
In additional embodiments of the duplexer barrier system described herein, different drive systems for rotating the barrier system.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
