Abstract:
A media velocity decoupling device is part of a rotary nip diverter assembly and includes a one-way clutch connected to a drive roller of a rotary nip diverter gate. The one-way clutched drive roller allows for realignment of the rotary nip diverter gate during media transfer to a downstream nip while the media is captured in both the rotary nip diverter gate and the downstream nip without media slippage or stretching occurring.

Description:
This invention relates generally to a rotary nip diverter device, and more particularly, to a velocity decoupling device incorporated within the rotary nip diverter device for high speed diverting of media or sheets away from a sheet transport path into one of multiple downstream paths. 
     BACKGROUND 
     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 charges thereon 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 by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to 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. The toner particles are heated to permanently affix the powder image to the copy sheet. 
     SUMMARY 
     In printing machines such as those described above, it is necessary to mechanically divert media from an input baffle to one or more downstream baffles, for example, when media needs to be inverted, and traditional diverter gates must be actuated in the inter-copy gap between the incoming media. However as the speeds of the media increase and the inter-copy distances/times are reduced, the time available during the inter-copy gaps is becoming less than can be achieved by these traditional diverter gates. 
     More specifically, as speeds and throughput requirements are increased the inter-copy gap spacing and timing are reduced. Traditional diverter gate assemblies rely on this inter-copy gap to actuate. The gate cannot be actuated prior to the trail edge (TE) of the previous sheet having cleared the gate and the gate must complete its actuation prior to the arrival of the lead edge (LE) of the following sheet. 
     The reaction times of the diverter assemblies are limited by the electro-mechanical actuation devices, such as, solenoids or stepper driven gates and their ability to actuate during the inter-copy gap timing. For example, a system running at approx. 1000 mm/s with a 40 mm inter-copy gap only allows for 40 ms of actuation time, trail edge to lead edge (TE to LE). That is, as that inter-copy distance is reduced or the media velocity is increased, the actuation time allowed during the inter-copy gap becomes very short. 
     An answer to this problem is the ability to have a rotary nip diverter mechanism that can be actuated to direct the sheet to the selected downstream nip prior to the inter-copy gap—while the sheet is within the nip. This changes the nip actuation from the short timing of the inter-copy gap to the much longer timing available when the media is captured in the rotary nip diverter gate. For example, at the same 1000 mm/s with an 8.5″×11″ sheet, the system has approximately 320 ms of divert timing (LE to LE) compared to the 40 ms of inter-copy gap timing (TE to LE). However, an issue with rotating the diverter nip while the sheet is in the nip is caused by the sheet being simultaneously held in a downstream nip. The rotation of the diverter nip will, by design, create a tension in the sheet that could cause unwanted stretch or slip. 
     U.S. Pat. No. 5,201,517 shows how an orbiting nip is used to guide a sheet&#39;s leading edge held in a nip to a different direction only. It does not provide for the nip to pivot when the lead edge of that sheet is held by a downstream nip. It also does not provide a solution to the inter-copy gap problem presented by a shortened inter-copy gap time created by the faster speeds needed to meet the higher throughput requirements. 
     Thus, a need still exists for an apparatus that overcomes this problem of velocity mismatch. 
     Accordingly, a rotary nip diverter assembly is disclosed that provides decoupling that is required to allow a rotary nip to be actuated while media is controlled by both the rotary nip of the rotary nip diverter assembly and a downstream nip of a selected baffle. The rotary nip diverter assembly employs a rotary nip diverter gate roll and a one-way clutch within the rotary nip diverter gate roll to provide decoupling of the rotary nip diverter gate roll from the downstream nip drive. By including the decoupling function in the rotary nip drive itself, the diverter action can be completed while the media is within the nip rather than solely having to occur during the inter-copy gap. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various of the above-mentioned and further features and advantages will be apparent to those skilled in the art from the specific apparatus and its operation or methods described in the example(s) below, and the claims. Thus, they will be better understood from this description of these specific embodiment(s), including the drawing figures (which are approximately to scale) wherein: 
         FIG. 1  is a frontal view of the rotary nip diverter gate of the present disclosure showing it in a first position; 
         FIG. 2  is a frontal view showing the rotary nip diverter gate in the first position of  FIG. 1  with media under control of both the rotary nip diverter gate and a downstream exit nip in an exit baffle; and 
         FIG. 3  is a frontal view of the rotary nip diverter gate of  FIG. 2  showing the rotary nip diverter gate in a second position with media under control of both the rotary nip diverter gate and the downstream exit nip in the exit baffle. 
     
    
    
     DETAILED DESCRIPTION 
     While the disclosure will be described hereinafter in connection with a preferred embodiment thereof, it will be understood that limiting the disclosure to that embodiment is not intended. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the disclosure as defined by the appended claims. 
     The disclosure will now be described by reference to a preferred embodiment within a xerographic printing apparatus that includes a method and apparatus for decoupling velocities between a rotary nip of a diverter and a nip in downstream baffles. 
     For a general understanding of the features of the disclosure, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to identify identical elements. 
     Referring now to rotary nip diverter assembly  10  in  FIG. 1 , and in accordance with the present disclosure, it includes a velocity decoupling device as a part of the rotary nip diverter assembly  10  that allows for the needed drive of media through the rotary nip diverter assembly and balances that drive with the added function of allowing for the decoupling of any velocity mismatch created by the rotation of the diverter mechanism. The decoupling device comprises a conventional one-way clutch (for example, a drawn cup roller clutch sold by The TIMKIN Company, Canton, Ohio) (not shown) that is installed within drive roller  16  with the drive roller in turn installed over a conventional drive shaft. This drive shaft is rotated in a conventional manner and as the shaft turns the one-way clutch will lock to the shaft to create drive to roller  16 . When a sheet being driven by the rotary gate drive roller nip is pulled at a higher velocity by a downstream nip, rotary nip roller  16  is free to rotate faster than the rotary nip drive shaft is turning. The one-way clutch allows for free movement at any velocity above the angular velocity of the shaft. A suitable one-way clutch is also shown in U.S. Pat. No. 5,428,431 and incorporated herein by reference. An idler roller  14  forms a rotary drive nip gate  12  with drive roller  16  and drives sheets or media  11  in the direction of arrow  13  between baffle assembly  20  and into either baffle assembly  30  and into a nip formed between drive roller  24  and idler roller  22  in the direction of arrow  15  or in the direction of arrow  17  and into baffle assembly  40  for capture by a nip formed between idler roller  26  and drive roller  28  depending upon positioning of rotary nip gate  12  of rotary nip diverter assembly  10 . 
     In addition, the one-way clutch can have frictional loading to maintain a pre-determined level of tension in the sheet. 
     In  FIG. 1 , rotary nip diverter gate  12  of rotary nip diverter assembly  10  is shown rotated to drive media into exit baffle assembly  30 , while in  FIG. 2  the rotary nip diverter gate  12  is shown pivoted with media  11  under control of both the rotary nip diverter gate  12  and a downstream nip formed between idler roller  22  and drive roller  24  within exit baffle assembly  30 . Rotary nip diverter gate  12  is shown pivoted in  FIG. 3  to direct media to downstream nips in exit baffle  40  while media is still within the rotary nip, thereby allowing for the previous media to complete handoff to exit baffle  30  nip. This completes a divert motion using sheet timing in addition to inter-copy gap spacing while allowing for the diverter to be actuated while sheet is simultaneously in the diverter and a downstream nip allowing for higher media speeds and overcoming limitations of traditional diverter actuators functioning only in the inter-copy gaps. 
     In recapitulation, a rotary nip diverter system with an integrated velocity decoupling device is disclosed as a part of a roller nip assembly. The integrated velocity decoupling device facilitates the performance of a velocity decoupling within the rotary nip diverter system, thereby enabling the rotary nip diverter to be actuated while media is held simultaneously within the nip diverter system and a downstream nip. The use of a one way clutch provides the lock and pivoting direction for the media within the diverter system. The result is that this system would enable the subsequent sheet to be accurately directed to the appropriate baffle prior to the inter-copy gap of the trail edge of the current sheet in the diverter. In addition, the use of a one-way clutch allows for the diverter to be actuated while a sheet is simultaneously within the diverter and a downstream nip allowing for higher media speeds and overcoming limitations of traditional diverter actuators functioning only in the inter-copy gaps. It can also eliminate the need for a nip release mechanism in diverter baffle designs and eliminates the need to incorporate an active control system to manage the velocity mismatch due to the gate motion and downstream nip. 
     The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color, or material.