Abstract:
An imaging architecture and method for duplex printing including a first imaging station operative to mark a first side of a substrate media with a first image, a first media transport module configured and operative to convey the substrate media in proximity with the first imaging station in a process direction along which the substrate media passes through the imaging architecture, and to invert the orientation of the substrate media without interrupting the conveyance of the substrate media in the process direction. A second imaging station is operative to mark the inverted substrate medium on a second side opposing the first side with a second image, and a second media transport module is configured and operative to convey the inverted substrate media in proximity with the second imaging station in the process direction.

Description:
BACKGROUND 
       [0001]    1. Field of the Disclosure 
         [0002]    The present disclosure relates document creation. More specifically, the present disclosure is directed to an improved system and method for printing on both sides of a sheet medium. 
         [0003]    2. Brief Discussion of Related Art 
         [0004]    In a printer it is often desirable to print text, images, or the like, on both sides of a substrate medium (e.g., paper, vellum, etc.), known in the art as “duplex” printing. Current state of the art in duplexing technology involves printing on one side of the medium, for example a cut sheet medium, and diverting medium having already been printed on one side, away from the process path and feeding the medium into a blind spur off the process path. In the blind spur, the cut sheet is stopped, and then reversed in direction to be fed back into the process path in a reversed orientation, e.g., what was the trailing edge now being the leading edge, and vice-versa, and the orientation of the flat sheet sides of the cut sheet medium is reversed as well. The cut sheet medium is thereby inverted by the diversion process. 
         [0005]    This technique has drawbacks. Among these, the inverter spur off the process path occupies space in the unit which is only occasionally and optionally used. The reversal of direction of the cut sheet medium requires a re-registration of the medium in the process path for acceptable image quality. The reversal process also interrupts the flow of media through the process path as a whole, and therefore reduces print cycle time (e.g., pages per minute, PPM). The current state of the art in duplex direct marking print technology is therefore wanting. 
       SUMMARY 
       [0006]    In order to overcome these and other drawbacks in the present state of the art, provided according to the present disclosure is an imaging architecture comprising a first imaging station operative to mark a substrate media with a first image, a first media transport module configured and operative to convey the substrate media in proximity with the first imaging station in a process direction along which the substrate media passes through the imaging architecture, and to invert the orientation of the substrate media without interrupting the conveyance of the substrate media in the process direction. A second imaging station is operative to mark the inverted substrate media with a second image, and a second media transport module is configured and operative to convey the inverted substrate media in proximity with the second imaging station in the process direction. 
         [0007]    In further embodiments, the first media transport module is configured and operative to invert the substrate media around an axis transverse to the process direction. The second media transport module may also be configured and operative to invert the orientation of the substrate media without interrupting the conveyance of the substrate media in the process direction, in particular around an axis transverse to the process direction. 
         [0008]    The first or second imaging stations may comprise a direct marking technology to mark the substrate media with a respective first or second image. The first or second imaging station may comprise a plurality of imaging engines, each of the plurality of imaging engines configured and operative to mark the substrate media according to a predetermined characteristic. 
         [0009]    In certain embodiments, the first media transport module is configured and operative to apply a hold down force sufficient to hold the substrate media against the first media transport module, and to release the inverted substrate media at a predetermined position of the substrate media. The first media transport module may be configured and operative to effect a localized interruption of the hold down force to release the inverted substrate media. Alternately or additionally, a barrier may be provided near or against the first media transport module, operative to separate the substrate media from the first media transport module. The barrier may have a knife edge positioned to come between the substrate media and the first media transport module. Alternately or additionally, a fluid nozzle configured and operative to direct a flow of fluid towards the first media transport module sufficient to separate the substrate media from the first media transport module is provided. 
         [0010]    In a further embodiment, at least one image treatment station is positioned downstream in the process path from the first or second imaging station. The image treatment station is operative to apply a treatment to the substrate media to affix the first or second image thereto. 
         [0011]    Also provided by the present disclosure is a method of duplex printing including conveying, with a first media transport module, a substrate media through an imaging architecture in a process direction along which the substrate media passes through the imaging architecture, in proximity with a first imaging station operative to mark the substrate media with a first image. The orientation of the substrate media is inverted without interrupting the conveyance of the substrate media in the process direction, the inverted substrate media conveyed in proximity with a second imaging station operative to mark the substrate media with a second image. Inverting the orientation of the substrate media may be performed around an axis substantially transverse to the process direction. 
         [0012]    The substrate media may be held to the first media transport module, for example by one or more of a vacuum force and an electrostatic force. The inverted substrate media is released from the first media transport module, for example by interrupting a force holding the substrate media to the first media transport module at a predetermined position of the substrate media, and conveyed to a second media transport module for conveyance in proximity with the second imaging station. Alternately or additionally, releasing the substrate media from the first media transport module includes a physical barrier imposed between the substrate media and the first media transport, the physical barrier optionally having a substantially knife edge presented at the interface of the substrate media and the first media transport module. 
         [0013]    The presently disclosed method optionally includes inverting the inverted substrate media following its transport in proximity with the second imaging station, in some cases without interrupting the conveyance of the substrate media in the process direction, and in some cases around an axis substantially transverse to the process direction. 
         [0014]    These and other purposes, goals and advantages of the present application will become apparent from the following detailed description of example embodiments read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Some embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings in which: 
           [0016]      FIG. 1  illustrates a duplex architecture according to an embodiment of the present disclosure, showing a substrate media in a preliminary position along the process path; and 
           [0017]      FIG. 2  illustrate the exemplary duplex architecture according to the embodiment of  FIG. 1 , showing the substrate media in an intermediate position along the process path. 
       
    
    
     DETAILED DESCRIPTION 
     Introduction 
       [0018]    As used herein, a “printer” refers to any device, machine, apparatus, and the like, for forming images on substrate media using ink, toner, and the like. A “printer” can encompass any apparatus, such as a copier, bookmaking machine, facsimile machine, multi-function machine, etc., which performs a print outputting function for any purpose. Where a monochrome printer is described, it will be appreciated that the disclosure can encompass a printing system that uses more than one color (e.g., red, blue, green, black, cyan, magenta, yellow, clear, etc.) ink or toner to form a multiple-color image on a substrate media. 
         [0019]    As used herein, “substrate media” refers to a tangible medium, such as paper (e.g., a sheet of paper, a long web of paper, a ream of paper, etc.), vellum, transparencies, parchment, film, fabric, plastic, paperboard or other substrates on which an image can be printed or disposed. 
         [0020]    As used herein “process path” refers to a path traversed by a unit of substrate media through a printer to be printed upon by the printer on one or both sides of the substrate media. A unit of substrate media moving along the process path from away from its beginning and towards its end will be said to be moving in the “process direction”. 
         [0021]    As used herein, “straight line” refers to the substrate media traveling along a process path in a process direction away from the beginning of the process path and towards the end of the process path without stoppage, and/or more particularly, reversal. “Straight line” does not imply or require that the process path or the substrate media traversing it is precluded from rotation or translation in three-dimensional space. 
       Description 
       [0022]    Referring now to  FIG. 1 , illustrated schematically is a straight-line duplex imaging architecture, generally  10 , according to an embodiment of the present disclosure. A substrate media  12  to be printed upon, in the exemplary embodiment only a cut sheet of paper, is introduced into a process path  14  and transported to a first imaging station  16 . In the exemplary embodiment the imaging station is a direct marking imaging station and uses the influence of gravity to carry a marking ink from the imaging station to the substrate media  12 . The first imaging station  16  may include a plurality of imaging engines  16   a ,  16   b ,  16   c , etc. For example, but without limitation, each of the plural imaging engines  16   a ,  16   b ,  16   c  may be configured to mark the first side  12   a  of the substrate media  12  according to a predetermined characteristic, including without limitation a particular type or color ink. 
         [0023]    In some cases, it may be advantageous to accelerate a drying or curing process of the first image marked on the first side  12   a  of the substrate media  12 . In that case a first image fixing station  18  may optionally be provided downstream in the process path  14  from the first imaging station  16 . In the case where the ink used to fix an image on the first side  12   a  of the substrate media  12  is fixed by drying, the first fixing station  18  may comprise a heat source and/or an airflow source directed at the image-marked first side  12   a  of the substrate media  12 . Alternately or additionally, the marking technology of the first imaging station  16  may include an ink that responds to ultraviolet (UV) radiation, in which case the first fixing station  18  may comprise a UV source, which exposes the first side  12   a  of the substrate media  12  to the UV radiation. 
         [0024]    The imaging architecture  10  further comprises a first media transport module  20 , comprising an endless belt  22  routed over at least two drum rollers  24 ,  26 . Either or both of drum rollers  24 ,  26  may be driven by a motor (not shown) to move the belt  22 . A non-driven roller among the two  24 ,  26  is an idler roller. The substrate media  12  is carried by the belt  22  past the first imaging station  16 , where an image is marked on a first side  12   a  of the substrate media  12 . Further, the first media transport module is operative to hold the substrate media  12  against the belt  22 , for example by vacuum pressure as is known in the art, but alternately or additionally by electrostatic force, also in conventional fashion. The first media transport module  20 , and particularly the endless belt  22 , holds and/or carries the substrate media  12  as the belt travels around roller  26 , thereby inverting the substrate media  12  with respect to an axis transverse to the process direction. 
         [0025]    In the depicted embodiment, the substrate media  12  is inverted by turning it over the drum roller  26  with the endless belt  22 , i.e., around an axis transverse to the process path  14 . It is contemplated in an alternate embodiment that the substrate media  12  is inverted by turning it with respect to an axis aligned or substantially parallel with the direction of the process path  14 . 
         [0026]    The substrate media  12  is released from the first media transport module  20 , in this particular embodiment at or about an underside  28  of the roller  24 , and delivered towards a second imaging station  30 . The substrate media  12  may be released from the first media transport module by a physical barrier  52 , in particular one with a knife edge  54  or the like, which may be imposed near or against the surface of the endless belt  22 . Configured at or near the interface of the endless belt  22  and the substrate media  12 , the barrier  52  prevents a substrate media  12  from continuing beyond a desired point where the barrier  52  is located which remaining engaged with the endless belt  22 . 
         [0027]    Alternately or additionally, the substrate media is separated from the first media transport  20  by application of a specifically directed fluid flow (e.g., air) from a release nozzle  56  ( FIG. 2 ). The flow of air from the release nozzle is set to be sufficient and operative to separate the substrate media  12  from the endless belt  22  and the first media transport module  20  against the vacuum, electrostatic or similar holding force. 
         [0028]    Alternately or additionally, the vacuum force holding the substrate media  12  to the endless belt  22  of the first media transport module  20  may be interrupted at a predetermined point to effect the release of the substrate media  12  from the endless belt  22 . Where electrostatic force is used in place of or in addition to vacuum pressure to hold the substrate media  12  to the endless belt  22  of the first media transport module  20 , the electrostatic force can also be interrupted and/or discontinued at the desired release point. 
         [0029]    Referring now to  FIG. 2 , illustrated is the straight-line duplex imaging architecture  10  as the substrate media  12  is delivered to a second imaging station  30 . A second media transport module  40 , comprising an endless belt  42  routed over at least two drum rollers  44 ,  46 . Either or both of drum rollers  44 ,  46  may be driven by a motor (not shown) to move the belt  42 . A non-driven roller among the two rollers  44 ,  46  is an idler roller. The substrate media  12  is carried by the belt  42  past the second imaging station  30 , where an image is marked on a second side  12   b  of the substrate media  12 . Further, the second media transport module is operative to hold the substrate media  12  against the belt  42 , for example by vacuum pressure as is known in the art, but alternately or additionally by electrostatic force, also known in the art. 
         [0030]    As a result of the inversion of the substrate media by the first media transport module  20 , a second side  12   b  of the substrate media  12  is facing upward to receive an image at the second imaging station  30 . The second imaging station  30  may include a plurality of imaging engines  30   a ,  30   b ,  30   c , etc. For example, but without limitation, each of the plural imaging engines  30   a ,  30   b ,  30   c , etc., may be configured to mark a different type or color ink on the second side  12   b  of the substrate media  12 . 
         [0031]    In some cases, it may be advantageous to accelerate a drying or curing process of the first image marked on the second side  12   b  of the substrate media  12 . In that case a second image fixing station  32  may optionally be provided downstream in the process path  14  from the second imaging station  30 . In the case where the ink used to fix an image on the second side  12   b  of the substrate media  12  is fixed by drying, the second fixing station  32  may comprise a heat source and/or an airflow source directed at the image-marked second side  12   b  of the substrate media  12 . Alternately or additionally, the marking technology of the second imaging station  30  may include an ink that responds to ultraviolet (UV) radiation, in which case the second fixing station  32  may comprise a UV source, which exposes the second side  12   b  of the substrate media  12  to the UV radiation. 
         [0032]    Having passed through the second imaging station  30 , the substrate media  12  is marked with an image on both a first side  12   a  and a second side  12   b , and is considered duplexed. Beyond the second imaging station  30 , the second media transport module  40 , and particularly the endless belt  42 , holds and/or carries the substrate media  12  as the belt travels around roller  46 , thereby again inverting the substrate media  12  with respect to an axis transverse to the process direction, such that a first side  12   a  of the substrate media  12  is facing upwards. The substrate media  12  is, in the depicted embodiment released from the second media transport module  40  at or about a bottom  48  of the roller  44 , and transported to an end  50  of the process path  14 . 
         [0033]    Alternately, the process path  14  may be terminated beyond the second imaging station  30  without further inversion by the second media transport module  40 . For example, it may be acceptable to the user to receive the duplex-printed substrate media  12  having a first side  12   a  face-down, either as a matter of course or by an affirmative selection. 
         [0034]    Still alternately, in the case that a particular instance of substrate media  12  is to be printed on a first side  12   a  only, the architecture  10  may include a diverter in the process path  14  beyond the first imaging station  16 . The substrate media  12  may be selectively diverted from the process path  14  to the end  50  of the process path. Such an embodiment and instance maintains the characteristic that the substrate media  12  moves in a single direction through the process path  14  without stoppage or reversal. This does, however, introduce the complexity of a diversion from a singular and unified process path  14 , by creating a compound process path  14  with more than one possible unique paths. 
         [0035]    It will be appreciated by those skilled in the art that certain alterations or modifications of the system and methods of the present disclosure, including their features and functions, or alternatives thereof, may be apparent. The same may be desirably combined into many other different systems or applications. The systems and methods disclosed are offered as merely exemplary of, and not liming on, the scope of the present disclosure. 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. 
         [0036]    For example, the exemplary embodiment has been described with reference to a cut sheet of substrate media  12 . It will be appreciated that this is an example only, and that the disclosed architecture  10  is applicable for use with a generally continuous web of substrate media  12 , without departing from the scope of the present disclosure.