Patent Publication Number: US-8125672-B2

Title: Dual ink systems in a printer

Description:
FIELD OF THE INVENTION 
     The invention relates generally to the field of ink-jet printing systems. More particularly, the invention relates to an ink-jet printer having multiple ink systems. 
     BACKGROUND 
     An ink jet printer is as an example of a printing apparatus that ejects droplets of ink onto a recording medium such as a sheet of paper, for printing an image of the recording medium. The ink jet printer includes a head unit having an ink jet head provided with an ink cartridge that accommodates the ink. In operation of the head unit, the ink is supplied from the ink cartridge to each ink jet head having ejection nozzles, so that a printing operation is performed by ejection of the ink droplets from selected ejection nozzles. 
     There are two general types of ink used in inkjet printers, dye-based ink and pigment-based ink. However, dye-based and pigment-based ink types are not interchangeable. Each ink type offers specific advantages over the other. In general dye inks tend to be cheaper but offer lower print quality than pigment inks. 
     Switching a print engine from operating using one ink type to operating with the other ink type necessitates a long and expensive process, and is generally not even considered as practical for production print houses. Therefore, a print house must choose one ink type for its printing operation, or purchase and operate two printers (one for each ink type) in order to have an ability to print using both print ink types. 
     However, high speed ink jet production printers may have a purchasing price as high as $3 million, which may limit the ability of some printing houses to operate printers that print using each ink type. 
     Accordingly, an ink-jet printer capable of efficiently operating with multiple ink types is desired. 
     SUMMARY 
     In one embodiment, an ink jet printing system is disclosed. The printing system includes a first print system having a first ink system to print received print jobs, a second print system having a second ink system independent of the first ink system to print the print jobs and a control unit to receive the print jobs and determine which of the first and second print systems is to print each received print job. 
     Another embodiment discloses a method of receiving a print job at a control unit within an ink jet printer, the control unit determining that the print job is to be printed at a first print system having a first ink system if the print job indicates that a first ink type is to be used for the print job and the control unit determining that the print job is to be printed at a second print system having a second ink system if the print job indicates that a second ink type is to be used for the print job. 
     A further embodiment discloses a network. The network includes one or more data processing systems, a print server to receive print jobs from each of the one or more data processing systems and an ink jet printer to receive the print jobs from the print server. The ink jet printer includes a first print system having a first ink system to print received print jobs, a second print system having a second ink system independent of the first ink system to print the print jobs and a control unit to receive the print jobs and determine which of the first and second print systems is to print each received print job. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the present invention can be obtained from the following detailed description in conjunction with the following drawings, in which: 
         FIG. 1  illustrates one embodiment of a data processing system network; 
         FIG. 2  illustrates one embodiment of an ink jet printer; 
         FIG. 3  illustrates one embodiment of a print system; 
         FIG. 4  illustrates a high speed ink jet printer; 
         FIG. 5  illustrates one embodiment of a high speed ink jet printer; 
         FIG. 6  illustrates another embodiment of a high speed ink jet printer; and 
         FIG. 7  illustrates one embodiment of a desktop ink jet printer. 
     
    
    
     DETAILED DESCRIPTION 
     A dual ink print system mechanism for ink jet printer is described. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form to avoid obscuring the underlying principles of the present invention. 
     Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
       FIG. 1  illustrates one embodiment of a data processing system network  100 . Network  100  includes a data processing system  102 , which may be either a desktop, host computer or a mobile data processing system, coupled via communications link  104  to network  106 . In one embodiment, data processing system  102  is a conventional data processing system including a processor, local memory, nonvolatile storage, and input/output devices such as a keyboard, mouse, trackball, and the like, all in accordance with the known art. In one embodiment, data processing system  102  includes and employs the Windows operating system or a similar operating system and/or network drivers permitting data processing system  102  to communicate with network  106  for the purposes of employing resources within network  106 . 
     Network  106  may be a local area network (LAN) or any other network over which print requests may be submitted to a remote printer or print server. Communications link  104  may be in the form of a network adapter, docking station, or the like, and supports communications between data processing system  102  and network  106  employing a network communications protocol such as Ethernet, the AS/400 Network, or the like. 
     According to one embodiment, network  106  includes a print server/printer  108  serving print requests over network  106  received via communications link  110  between print server/printer  108  and network  106 . The operating system on data processing system  102  is capable of selecting print server/printer  108  and submitting requests for services to print server/printer  108  over network  106 . Print server/printer  108  includes a print queue for print jobs requested by remote data processing systems  102 . Further, print server/printer  108  includes a control unit to perform operations associated with printing a request. 
     Although described as incorporated within the same entity, other embodiments may include the print server and the printer as being physically separate components. Therefore, the data processing system network  100  depicted in  FIG. 1  is selected for the purposes of explaining and illustrating the present invention and is not intended to imply architectural limitations. Those skilled in the art will recognize that various additional components may be utilized in conjunction with the present invention. 
       FIG. 2  illustrates one embodiment of an ink jet printer  200 . In one embodiment, ink jet printer  200  is implemented as the printing component of print server/printer  108 . Printer  200  includes a rasterizer  210 , memory array  220 , control unit  230  and print systems  240 A and  240 B. 
     Rasterizer  210  is implemented to convert vector information received at printer  200  into a raster format. Particularly, rasterizer  210  generates a raster scan of a received image that is to be stored as scan line data in memory array  220 . Control unit  230  controls the operation of print systems  240 A and  240 B. According to one embodiment, print systems  240 A and  240 B each utilize independent ink systems to perform a print job directed by control unit  230 . 
     As a result, control unit  230  determines which of the print systems  240  is to perform a print job based on a predetermined operation selection. In such an embodiment, print system  240 A performs print jobs utilizing a dye-based ink, while print system  240 B is used for print jobs calling for pigment-based ink, or a custom ink. Thus, based on the type of ink to be used for the print job, control unit  230  selects the applicable print system  240 . 
     In another embodiment, print systems  240 A and  240 B utilize the same ink type. In this embodiment, one print system (e.g.,  240 A) is used for continuous printing while the other (e.g.,  240 B) serves as a backup. At certain intervals, or when needed, print system  240 B will be used when print system  240 A is taken offline for maintenance and servicing. Thus, printer  200  is always available for use, even during servicing. In a further embodiment both independent print systems  240 A and  240 B within printer  200  may be used so that ink from both systems may be used on the same page of a print job. 
       FIG. 3  illustrates one embodiment of a print system  240 . In one embodiment, each print system  240  includes ink containers  310 , ink lines  320  and a print head  350 . Ink containers  310  include one or more ink colors that supply one or more ink reservoirs to print head  350  via ink lines  320 . In one embodiment, ink containers  310  are bottles. However in other embodiments, ink containers  210  may be a bladder, cartridge or other type of supply containers. 
     Print head  350  includes a printing element that prints to a print medium. According to one embodiment, print head  350  is a wide-array inkjet print head that employs multiple sets of nozzles that are implemented to spray droplets of ink onto a sheet of paper in order to execute a print job. However, print head  350  may include other types of ink jet print heads, as well as a moving print head design. 
       FIG. 4  illustrates an exemplary high speed ink jet printer employing a single print system. As shown in  FIG. 4 , the print system includes a single set of ink lines and a print head with nozzles. 
       FIG. 5  illustrates one embodiment of a high speed ink jet printer employing dual print systems  240 A and  240 B. In this embodiment, the print heads  350 A and  350 B are covered by respective docking stations. In the embodiment shown in  FIG. 5 , the two sets of print heads  350 A and  350 B are docked vertically. In this embodiment, the docking stations move in a vertical direction to lower the second set of print heads  350 B such that they are at a proper height for moving into the ready position over a paper path  505 . 
       FIG. 6  illustrates another embodiment of a high speed ink jet printer employing dual print systems  240 A and  240 B. In this embodiment, print heads  350 A and  350 B with their respective docking stations are oriented on each side of the paper path  505 . 
     Although discussed above with respect to high speed production printers, other ink-based printers (e.g. work group and home printers) may be include multiple print systems  240 .  FIG. 7  illustrates one embodiment of a desktop ink jet printer. In this embodiment, two print cartridges  710 A and  710 B are fitted with a clamp that attaches to a drive belt  705 . A clamp  707  holds drive belt  705  tightly or releases gripping tension to allow belt  705  to freely move. When print cartridge  710 A is in use its clamp holds drive belt  705  while the print cartridge  710 B clamp allows belt  705  to move freely. Thus, print cartridge  710 B remains in a parked position. 
     The above-described mechanism enables print shops to offer multiple types of ink without having to buy multiple printers and avoids any down time associated with the swapping of ink types. In addition, the mechanism enables continuous printing operation when a print head system needs to be taken offline for service and maintenance. 
     Whereas many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description, it is to be understood that any particular embodiment shown and described by way of illustration is in no way intended to be considered limiting. Therefore, references to details of various embodiments are not intended to limit the scope of the claims, which in themselves recite only those features regarded as essential to the invention.