Patent Grant
8967792
The present disclosure relates to an apparatus for and method of holding sheets of substrate media on a moveable platen in a printing system.
High speed inkjet marking devices for large sized cut sheets are particularly constrained using contemporary systems with regard to production output, media type and image quality. Systems that handle such large sized cut sheets can use an oversized media platen to support the sheet during the marking process, but placement and registration of the sheet on the platen requires precision. Also, once the sheet is moved into the desired registration position, that position must be reliability maintained. However, such large sheets are particularly difficult to manipulate into and maintain in proper registration upon the platen, particularly if it is a moveable platen.
What is more, providing a vacuum source on a moveable platen adds further problems. A tether or vacuum support line onto a moveable platen limits the configurability of the system. Also, such connections impact motion control and incur additional costs.
Accordingly, it would be desirable to provide an apparatus for and method of retaining substrate media sheets on a platen cart that does not require a tether or fixed line support to maintain a vacuum on a platen cart in order to hold the sheet down and overcomes the various shortcomings of the prior art.
According to aspects described herein, there is disclosed an a moveable platen cart for handling sheets of substrate media in a printing system. The platen cart includes a cart frame configured to translate along a process track. A media platen is secured to the cart frame, and the media platen has a foraminous upper surface for receiving a substrate media sheet thereon. The media platen has a subsurface cavity in fluid communication with the foraminous upper surface. A vacuum port is provided for evacuating air from the cavity, and a valve is provided for selectively closing and opening the vacuum port.
According to further aspects described herein, there is disclosed an apparatus for conveying sheets of substrate media in a marking device. The apparatus includes a track extending along a process direction, and a moveable platen cart. The cart is configured to translate along the track. The cart has a media platen secured thereto. The media platen has a foraminous upper surface for receiving a substrate media sheet thereon. The media platen has a subsurface chamber in fluid communication with the foraminous upper surface. The cart including a vacuum port for evacuating air from the cavity, and the vacuum port is selectively sealable. The chamber maintains a vacuum when a sheet of substrate media is on the media platen upper surface and the vacuum port is disconnected from a vacuum source.
According to further aspects described herein, there is disclosed an a method of securing a sheet of substrate media on a media platen for handling in a printing system, the method including loading a substrate media sheet onto a media platen located in a loading position, the media platen including a foraminous upper surface for engaging the substrate media sheet; opening a valve to generate a negative flow of air through the foraminous upper surface, the negative flow of air encouraging the substrate media sheet to remain fixed and engaged upon the foraminous upper surface; closing the valve to maintain the negative pressure and retain the media on the platen; and moving the media platen for the loading position with the media retained on the platen by the negative pressure.
Describing now in further detail these exemplary embodiments with reference to the Figures. The disclosed technologies improve image quality for large format print jobs, while providing an efficient sheet registration and handling system that can improve productivity. The apparatus and methods disclosed herein can be used in a select location or multiple locations of a marking device path that includes a pneumatic table. Thus, only a portion of an exemplary pneumatic table and methods of use thereof are illustrated herein.
As used herein, “substrate media sheet”, “substrate media” or “sheet” refers to a substrate onto which an image can be imparted. Such substrates may include, paper, transparencies, parchment, film, fabric, plastic, photo-finishing papers, corrugated board, or other coated or non-coated substrate media upon which information or markings can be visualized and/or reproduced. While specific reference herein is made to a sheet or paper, it should be understood that any substrate media in the form of a sheet amounts to a reasonable equivalent thereto. Also, the “leading edge” of a substrate media refers to an edge of the sheet that is furthest downstream in a process direction.
As used herein, “sensor” refers to a device that responds to a physical stimulus and transmits a resulting impulse in the form of a signal for the measurement and/or operation of controls. Such sensors include those that use pressure, light, motion, heat, sound and magnetism. Also, each of such sensors as refers to herein can include one or more sensors for detecting and/or measuring characteristics of a substrate media, such as speed, orientation, process or cross-process position and even the size of the substrate media. Thus, reference herein to a “sensor” can include more than one sensor.
As used herein, “marking zone” refers to the location in a substrate media processing path in which the substrate media is altered by a “marking device.” Marking devices as used herein include a printer, a printing assembly or printing system. Such marking devices can use digital copying, bookmaking, folding, stamping, facsimile, multi-function machine, and similar technologies. Particularly those that perform a print outputting function for any purpose.
Particular marking devices include printers, printing assemblies or printing systems, which can use an “electrostatographic process” to generate printouts, which refers to forming an image on a substrate by using electrostatic charged patterns to record and reproduce information, a “xerographic process”, which refers to the use of a resinous powder on an electrically charged plate record and reproduce information, or other suitable processes for generating printouts, such as an ink jet process, a liquid ink process, a solid ink process, and the like. Also, a printing system can print and/or handle either monochrome or color image data.
As used herein, the terms “process” and “process direction” refer to a process of moving, transporting and/or handling a substrate media sheet. The process direction substantially coincides with a direction of a flow path P along which a portion of the media sled moves and/or which the image or substrate media is primarily moved within the media handling assembly. Such a flow path P is said to flow from upstream to downstream. Accordingly, cross-process, lateral and transverse directions refers to movements or directions perpendicular to the process direction and generally along a common planar extent thereof.
As used herein, the term “media platen” refers to a a planar surface for carrying a sheet of substrate media.
As used herein, the term “platen cart” refers to a mobile device or moving a media platen or other planar member. The cart may move along in a guided manner along a track or rail.
As used herein, the term “foraminous surface” refers to a porous surface that allows air to pass there through. The surface may include be porous, perforated or otherwise include numerous holes so that air can pass through.
With reference to
Within the closed-loop process path defined by the rail support track 40, any number of other stations for application to the substrate media sheets 5 can be provided. For example, additional marking zones can be included, a sheet registration systems, paper cleaning elements, ink curing areas and various other functions that make up a sheet marking system. Considering the modular construction of the rail support track 40, these additional functions/features can be interchangeably added or removed from the apparatus 100 as desired.
As shown, the rail support track 40 includes a series of linear sections. In the illustrative embodiment of
Once the platen cart 80 rides onto the upper portion of the translation cart, it should stop so the translation cart can be moved along an extent of the laterally extending track section 45 in order to be conveyed to align with one of the other of the three parallel track sections. In this way, the platen cart 80 need not rotate or turn in order to translate along those laterally extending sections of track. Thus, the translation carts each move back and forth along the extent of one laterally extending track, rather than recirculating around the entire rail support track 40. Generally, the laterally extending track section 45 should each only include a single translation cart. However, if more than one translation cart is used on the same section of laterally extending track 45, then an extension portion (not shown) can be added to the laterally extending track 45. Such an extension portion should extend a short distance beyond one of the outside parallel track sections so that one translation cart can move out of the way of one or more other translation carts on the same section of track.
Ultimately, the rail support track 40 is assembled into a closed-loop, allowing the platen carts 80 to circulate around the track 40. For example, a sheet from the supply 10 can be loaded onto the cart 80 by the loading mechanism 92. Thereafter, the platen cart conveys a sheet 5 along the process direction P through the marking zone 20. Once the cart 80 reaches the shuttle section 45, the cart is conveyed laterally to one of the two routes R1, R2. In this way, the track 40 provides a looping rail system that forms a media path. As used herein, the term “loop” or “closed loop” with regard to the rail support track refers to a path that diverges from, and afterwards returning to, a starting point along the track. The loop can have alternative routes R1, R2, but preferably makes its way back to a common starting position. In this way, a platen cart 80 moving along the track 40 can re-circulate along one or more sections of the track 40.
The platen cart 80 and methods described herein are particularly useful for handling large size substrate media sheets. In particular, large size paper having dimensions of 62″×42″ can be easily accommodated by the disclosed technologies. What is more, larger sheets can be handled as long as the media platen 100 is sized accordingly.
Additionally, it should be understood that the platen cart 80 disclosed herein can be operated in conjunction with a controller (now shown). The controller may also control any number of functions and systems within or associated with the platen cart 80 and accompanying marking systems. The controller may include one or more processors and software capable of generating control signals. Through the coordinated control of the apparatus sub-elements, including a reversible air blower, horizontal biasing elements and sensors, the substrate media sheet may be effectively handled and marked. Further, it should be understood that the controller can also operate related items such as a vacuum source, a sheet loader for initially placing the substrate media sheet onto the platen cart 80.
In accordance with a further aspect of the disclosed technologies, the media platen 82 has an upper surface that includes foraminous portions 84. The foraminous portions can be porous, perforated or otherwise include numerous holes so that air can be pulled through the foraminous upper surface. In the illustrated embodiment, the foraminous upper surface 86 is shown in the four corners of the media platen 82.
Once a substrate media sheet is placed on the platen upper surface 84 and positioned in proper registration, a vacuum force will be generated for holding down a loaded sheet of substrate media. The substrate media sheet preferably covers the foraminous upper surface portions, thus preventing further air from flowing through that surface. By pumping any residual air out of a hollow vacuum chamber 88 within the platen cart, a negative pressure is created which will hold down the sheet. This vacuum force can hold the sheet secure to the platen surface while the platen translates from station to station until the pressure is released. Once the sheet is held on the platen cart it can proceed to a marking station or other handling stations until the sheet needs to be removed. Once the sheet needs to be removed, the negative pressure will be released by opening a valve 61. Once the vacuum hold down force is relieved, the sheet can then be removed from the platen cart and the cycle can be repeated for another sheet loaded thereon. Preferably, the vacuum station is located near the substrate media sheet loading station.
The platen cart vacuum port 60 operably coupled to the platen cart 80 is brought into coupling engagement with the vacuum port 60 upon the port sliding over and aligning with the coupling head 58 as shown in
The above-described moveable platen cart 80 eliminates the requirements for a tether or a vacuum line attached to the moveable platen cart. A moveable platen cart in accordance with aspects of the disclosed technologies can move about freely in a scalable system without limitations to configuration. Also, this system sees cost savings without the need for a power strip, blowers, lengths of hoses and other elements in order to provide a vacuum and maintain a negative pressure in order to hold down the substrate media sheet. The design according to the aspects described herein is scalable and can be implemented for various media types and weights.
It will be appreciated that variations of the above-disclosed and other features and functions, or alternative thereof, may be desirably combined into many other different systems or applications. 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. In addition, the claims can encompass embodiments in hardware, software, or a combination thereof.
| Number | Name | Date | Kind |
|---|---|---|---|
| 20100195083 | Fulwood et al. | Aug 2010 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20140160213 A1 | Jun 2014 | US |
