Abstract:
A custom designed drive mechanism to be utilized in conjunction with an ink jet printer having a motor, transmission, and gripping apparatus to transmit articles of manufacture to be printed upon through an enclosure having a linear bearing and spring system, an optical sensor, digital encoder and print mechanism such that the articles of manufacture travel in a single direction.

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATION 
   This Application is related to and claims the benefit under 35USC 119(e) for the Provisional Patent Application of the same title having Ser. No. 60/786,845 filed on Mar. 25, 2006. 

   FIELD OF THE INVENTION 
   This invention relates to ink jet printing. More specifically, the invention pertains to a system that uses ink jet printers in conjunction with a custom drive mechanism for the purpose of printing on one or both sides of the top portion of filled and sealed feed, seed and related product bags. 
   BACKGROUND OF THE INVENTION 
   Ink Jet printing is a common method of non-impact printing. An ink jet printer emits intermittent streams of ink droplets from tiny nozzles in response to received electrical signals. The present invention is applicable to all types of ink jet printers. 
   When used in industrial applications, specifically as it pertains to the printing of text, graphics or barcodes on feed, seed or similar product bags, conventional ink jet printers suffer from a variety of drawbacks and disadvantages. For example, when an ink jet print head becomes damaged the printing process must be stopped until inventive device  100  can be restored to proper operational status. For systems that contain fixed print heads this means that that an operator has to stop an assembly line and physically disconnect an ink jet printer from its ink supply and mounting so that it can be removed for maintenance. This is a time consuming and often expensive process, both in terms of the lost production stemming from a shut down line and the maintenance costs associated with servicing the print head. 
   In addition to the above, it is advantageous to incorporate both feed and print mechanisms in one unit. Having separate feed and printing mechanism can cause distortion in the print quality resulting from mismatched feed and print rates. Print quality is also compromised by warping, slippage, or buckling of bag  200  by the print handler. 
   Moreover, print quality due to “stitching”, a condition that occurs when overlapping print nozzles are not coplanar, is often un-adjustable or, if it can be adjusted it requires special tools to do so. Stitching results in a visible gap in between print produced by multiple print heads. The advantage of an adjustment mechanism to eliminate this condition is that overall print resolution increases as well as the number of applications that the printer may be used for. For example, very course inconsistent print may be acceptable for printing bar codes on feed bags, but stitching may prevent the inclusion of fine text or graphics. 
   Many existing industrial printers are not designed to print on both sides of bag  200  simultaneously. 
   Industrial ink jet applications require specialized ink delivery systems. To overcome the shortcomings of existing ink jet industrial print systems, a customized feed mechanism and print head system is provided. The first object of the invention is to provide even and uniform transport of bag  200  through a printing system. A related object is to link the feed mechanism to a closed loop system wherein the print speed may be matched to the speed in which the transport mechanism is operating. Another object of the invention is to provide transport for print mediums, such as bag  200 , of various thicknesses. It is yet another object of the invention to incorporate mechanisms that serve to eliminate stitching quickly and without the use of tools. It is still another object of the invention to enable the quick tool-less replacement of print heads. Another object of the invention is to place print accurately and repeatedly at a predetermined distance from the leading edge of bag  200 . Lastly, it is an object of this invention to place print on two sides of bag  200  simultaneously. 
   SUMMARY OF THE INVENTION 
   It is to be understood that both the foregoing and general description and the following detailed description are exemplary, but are not restrictive, of the inventive device  100 . In accordance with the principles of the present invention, a print system includes a printer and material handler. As illustrated in  FIG. 1 , the inventive device  100  consists of six main components: a motor and drive system  101 , a mechanical enclosure  102 , a linear bearing and spring system  103 , an optical sensor  104 , a digital encoder (not visible)  105 , and a print mechanism  106 . Inventive device  100  is designed to operate with product traveling in only one direction and to place ink jet print on section  203  of bag  200 , shown in  FIG. 13 . 
   Mechanical enclosure  102  encloses print and drive mechanisms  106 , and serves to attach the system to an external support member. Mechanical enclosure  102  is made up of two halves which are joined by the linear bearing and spring assembly  103  and a drive system  101 . Inlet guides at the front of mechanical enclosure  102  funnel bag  200  into a channel defined by the separation between the two halves of mechanical enclosure  102 . On each side of mechanical enclosure  102  a door  19  allows access to a print mechanism  106 . 
   Linear bearings and spring assembly  103  connect the two sides of mechanical enclosure  102  and allow for a variety of print medium, such as bag  200  thicknesses, such as portion  203  of bag  200 , shown in  FIG. 13 . 
   The entry of section  203  of bag  200  into the inventive device  100  breaks a beam of light provided by optical sensor  104  slightly offset from the portion of mechanical enclosure  102  directly in front of the inlet guides  12 , shown in  FIG. 6 . This entry action triggers the start of a print operation. 
   A drive mechanism consisting of motor  56 , transmission  800  and four knurled  16  wheels firmly and securely transport bag  200  through the inventive device for the purpose of printing. The wheels are opposed such that they “pinch” bag  200  for transport free of slippage, warpage or buckling of bag  200 . 
   Attached to one of the drive wheels inside mechanical enclosure  102  is digital encoder  96  that constantly monitors the speed of the wheels and bag  200 . 
   Print mechanism  106  consisting of an ink jet printer assembly and adjustment knobs  58 A and  58 B applies print on section  203  of bag  200 , shown in  FIG. 13 , as it passes through the system. Print mechanism  106  contains overlapping print cartridges, wherein each individual cartridge can print a set print height. By ganging multiple print cartridges, the system can print up to two inches of print height. Adjustment knobs  58 A and  58 B are used to raise or lower the print height relative to the feed bag&#39;s stitching and to position the print heads so that overlapping ganged print cartridges are coplanar. 

   
     DESCRIPTION OF FIGURES 
       FIG. 1  is an isometric view of the complete inventive device  100  with the access doors  19  open revealing a print head  106  on the inside of inventive device  100 . 
       FIG. 2  contains several isometric views for the purpose of sequentially illustrating how bag  200  travels through the inventive device  100  during the printing process. 
       FIG. 3  is an isometric view showing the metal top plates of the assembly. 
       FIG. 4  is an isometric view showing a sub-assembly consisting of top metal plates and a linear bearing assembly. 
       FIG. 5  is an isometric view illustrating how the product skids mate to the bottom plates. This view is also used to illustrate the path in which bag  200  travels and where the ink jet print heads protrude for printing. 
       FIG. 6  is an isometric view showing how various sheet metal components join to compose a frame. 
       FIG. 7  contains two isometric views of the drive wheels, shafts and transmission as well as a detailed view of a transmission component. 
       FIG. 8  is a front-top view of the transmission sub-assembly and two front wheels and encoder used for the purpose of illustrating the relationship of the various components. 
       FIG. 9  is an isometric view showing the interface of the drive motor sub-assembly with inventive device  100 . 
       FIG. 10  is an isometric view highlighting the digital encoder sub-assembly. 
       FIG. 11  is an isometric view showing several sheet-metal components and a detailed view of a component used to adapt inventive device  100  to an external member. Reference is also made to show where the digital encoder sub-assembly is located within inventive device  100 . 
       FIG. 12  is an isometric view highlighting the print head sub-assembly, the print head adjustment mechanisms and how the sub-assembly mates with the inventive device. 
       FIG. 13  is an isometric rendering of the preferred embodiment of bag  200 , a bag containing animal feed material. This figure shows the bag&#39;s stitching and the effective print area as it pertains to the inventive device  100 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   For simplicity and illustrative purposes, the principles of the present invention are described by referencing mainly to an exemplary embodiment thereof, particularly with references to an example of the inventive device  100 . However, one of ordinary skill in the art would readily recognize that the same principles are equally applicable to, and can be implemented in, any device designed to print on feed or seed bags or similar printing mediums. 
   Referring to all the drawings, it is to be understood that, according to common practice, the various components of the drawing may or may not be to scale. Reference numerals refer to components throughout the drawings, however, different drawings may not have common numerical references. 
   As illustrated in  FIG. 1 , the inventive device  100  consists of six main components: a motor and drive system  101 , a mechanical housing  102 , a linear bearing and spring system  103 , an optical sensor  104 , a digital encoder (not visible)  105 , and a print mechanism  106 . The system is designed to operate with print medium traveling in one consistent direction. 
   The object of the inventive device  100 , as it pertains to  FIG. 13 , is to place print, by way of an ink jet printing process, on print medium. In the preferred embodiment the print medium is section  203  of bag  200 , a product bag containing grain feed material, however, it is to be understood that the inventive device  100  shall not be restricted to printing on bags, and may be used to print on a variety of print mediums. With further respect to  FIG. 13 , section  202  is a stitching element used to isolate the fill material in bag  200  from the section  203 . Section  201  contains bag  200  filler material. 
   Referring to  FIG. 2 , the printing on bag  200  as depicted in  FIG. 2 , occurs in four fundamental steps. Note that several components have been hidden from view so as to expose the inner mechanics of inventive device  100  for the purpose of detailing the sequential steps involved in the operation. In addition, no structural support members are shown supporting inventive device  100 . 
   Position  1 , Detail A shows bag  200  traveling down an assembly line (not labeled) which passes in front of the optical sensor  104 . At this time the optical sensor  104  detects the leading edge of the bag  200 . This triggers an external control device (not shown) to start a printing process as bag  200  reaches skid plates  12 . 
   Position  2 , Detail B shows skid plates  12  channeling bag  200  between skid tractors  48  where it is picked up by in-feed knurled wheels  27  and fed through the system at a uniform rate of speed. In-feed knurled wheels  27  grab bag  200  and pull it into the print area at a manually set speed. The incompressible nature of bag  200  forces the two halves of inventive device  100  to separate by the thickness of bag  200  thusly increasing the force on the tension springs  34  (not shown). The increased tension pinches bag  200  between in-feed knurled wheels  27  resulting in smooth controlled transport through inventive device  100  without slippage, warping or buckling. 
   Position  3 , Detail C shows how printing occurs when the leading edge of bag  200  reaches a certain distance from the front of print head  106 . Distance is calculated using the information from optical sensor  104  in conjunction with the velocity of bag  200  obtained from encoder  96  (not shown). 
   Position  4 , Detail D shows exit-feed knurled wheel  48  pulling bag  200  through inventive device  100 . The combination of the in-feed and exit-feed wheels knurled wheels  48 , hold bag  200  securely without slippage, warping, or buckling during the printing process. 
     FIG. 3  shows sub-assembly  300  which forms the top of mechanical enclosure  102  of  FIG. 1 . Sub-assembly  300  consists of two independent metal plates—upper plate dummy  110  and upper plate  109  each containing two rigidly attached flange-mount bearings  111 . Flange-mount bearings  111  mount on the outside of inventive device  100  on upper plate dummy and upper plate,  110  and  109  respectively, via #4-40 screws  123  for quick replacement or service. 
     FIG. 4  demonstrates how sub-assembly  300 , shown in  FIG. 3 , joins with linear bearing assembly  103 , shown in  FIG. 1 , to form sub-assembly  400 . Shafts  115  and linear bearings  113  join the two halves of mechanical enclosure  102 , shown in  FIG. 1 . Shafts  115  are rigidly attached to upper plate dummy  110  via bar block a  117  and block c  118  using set screws  121 . Linear bearings  17  are secured in blocks b  113  by retaining rings  120  and blocks b are rigidly attached to upper plate  2 . Linear bearing assembly  103  allows upper plate  109  and upper plate dummy  110  to translate in one horizontal axis relative to upper plate dummy  110 . Two springs  34  compress upper plate dummy  110  and upper plate  109  together such that they provide positive force on bag  200  as it travels through inventive device  100 , and may expand or contract to accommodate various thicknesses of section  203  of bag  200 , shown in  FIG. 13 . Spring tension may be increased by moving two collars  98  on the end of each shaft inwards. The use of a single adjustable spring collar  98  on the portion of shaft  115  located between block b  118  and bar block a  117  controls the minimum distance between the two halves of assembly  400 . 
     FIG. 5  shows sub-assembly  500  which forms the bottom of mechanical enclosure  102 , shown in  FIG. 1 , and a product guide for section  203  of bag  200 , shown in  FIG. 13 . Holes in skid tractors  30  and  31  allow for the passage of print heads  106 , shown in  FIG. 1 , wherein they come in contact with section  203  of bag  200 , shown in  FIG. 13 , as it passes between skid tractors  30  and  31  during a printing operation. Skid tractors  30  and  31  are constructed of anodized aluminum. Although it is not shown an optional feature may include extending the height of skid tractors  30  and  31  to allow for additional print mechanism  106 , shown in  FIG. 1 , adjustment in the vertical direction. In addition, this would allow for the inclusion of additional print cartridges (not shown) required to produce additional print height. 
     FIG. 6  demonstrates how mechanical enclosure  102 , shown in  FIG. 1 , is made up of two part mechanical enclosure  600 . Two part mechanical enclosure  600  is constructed of several rigidly attached metal plates:  2 ,  7 ,  8 ,  9 ,  3 ,  4 ,  1 . Upright metal plates  2 ,  7 ,  8  and  9  serve to protect inventive device&#39;s  100  electronics and transmission mechanisms while doors  18  and  19  allow for restricted access to sub assemblies  106 , shown in  FIG. 1 , on both sides of inventive device  100 . Bag  200  enters two part mechanical enclosure  600  from product inlet guides  12  which compensate for a range of alignment of bag  200  on the assembly line (not shown) by funneling section  203  of bag  200  into inventive device  100 . The Tractor Frame halves  1  contain flange mount bearings  111  that mirror the placement of those on the Upper Plate  110  and upper plate dummy  109 . Doors  18  and  19  are secured by turn pawl latches  70  to the large uprights  2  and  9 . Although not shown in this assembly, it is possible to incorporate an optional power cut-off such that power to inventive device  100  is terminated when the doors  18  and  19  are opened. 
     FIG. 7  shows drive system  700  used to pull section  203  of bag  200  through inventive device  100 . Tractor long shaft  14 , tractor medium shaft  13 , and tractor short shafts  13  and  15  mate with the upper most and lower most portions of the mechanical enclosure  102 , shown in  FIG. 1 . Four knurled wheels  16 , tractor long shaft  14  and tractor medium shaft  13  evenly transmit power to both sides of inventive device  100  for the purpose of transporting print material through inventive device  100  without slippage, warping or buckling of bag  200 . Mechanical power is input in tractor long shaft  14 . Gear  22  attaches to the top of tractor long shaft  14  and transfers power to another gear  22  attached to the top of tractor medium shaft  13  via chain  28 . The two knurled wheels  16  attached at the bottom of long and medium shafts,  14  and  13  respectively, rotate at the same speed and in the same direction. Transmission  800 , shown in  FIG. 8  takes the power input from tractor long shaft  14  and transfers equal and opposite power to knurled wheels  16  on the other side of inventive device  100  such that knurled wheel  16  attached to tractor short shafts,  13  and  15  respectively, rotate at the same speed but in the opposite direction of knurled wheels  16  attached to tractor long  14  and medium shafts  13 . Knurled wheels  16  pull bag  200  through inventive device  100  at a constant and controlled rate of speed so that even and consistent printing can occur. Knurled wheels  16  are fixed such that slots in skid tractors,  30  and  31 , shown in  FIG. 5 , can not move in the vertical direction. However, inventive device  100  may be modified such that knurled wheels  16  may be made fully adjustable in the vertical direction in order to move within the extents of section  203  of bag  200 . 
     FIG. 8  shows gearbox assembly  800 , which consists of two halves connected via shaft  74 . Gearbox assembly  800  resides on the inside of mechanical enclosure  102 , shown in  FIG. 1 . In addition to connecting the two halves of gearbox assembly  800 , shaft  74  and two collars with screws  105  also connect the two halves of mechanical housing  102  Gearbox assembly  800  pivots around tractor short shaft  13 , tractor long shaft  14  and shaft  74 . This movement allows four knurled wheels  16  to expand or contract depending on the thickness of bag  200  passing through inventive device  100 . 
     FIG. 9  shows sub-assembly  900  which consists of motor and transmission  56 , which is rigidly attached to inventive device  100  by motor mount  26 . Power is transmitted from motor and transmission  56  through Lovejoy Jaw Type Coupling  58 ,  59 , and  67  first to tractor long shaft  14 , shown in  FIG. 8 , and thusly all four knurled wheels  16  (also not visible in this drawing). The power transmission area is enclosed with metal cover  41  to shield the rotating elements. Motor and transmission  56  operate at a continuous speed, however, inventive device  100  may be controlled by an external mechanism such that motor and transmission  56  speed may be adjusted to dynamically compensate for corresponding changes in the assembly line speed. 
     FIG. 10  shows sub-assembly  1000  which consists friction drive incremental encoder  96 . Friction drive incremental encoder  96  makes direct contact with in-feed knurled wheel  16  via encoder wheel  96 A. Encoder  96  is used to determine the speed of bag  200 . This information is required for proper printing in that the ink jet print speed must be precisely matched to the speed of bag  200 . Encoder  96  enables inventive device  100  to accommodate a range of print material speeds, and make dynamic adjustments to the rate of print in the event that bag  200  changes speed as it travels through inventive device  100  during the print process. 
     FIG. 11  shows sub-assembly  1100  consisting of covers  65 ,  115  and  24  used to shield the assembly mechanics, and angle mount brackets  2  used to mount the entire assembly to an external fixture. Angle mount brackets  19  securely attach the assembly to a 2″ square slotted aluminum extrusion (not shown) via four double t-nuts  122  and eight ¼-20 screws  41 . 
     FIG. 12  shows sub-assembly  1200 , consisting of two print mechanisms  106 . Each print mechanism  106  contains four print cartridges (not shown) each capable of producing a half-inch of print height. It should be noted that inventive device  100  contains two print mechanism  106  with four print cartridges (not shown) each for a maximum printing height of two inches. Moreover, employing two print mechanisms  106  enables inventive device  100  to print on both sides of bag  200  simultaneously. Print mechanism  106  may print characters, images or both. By increasing the number of print cartridges (not shown) in print mechanism  106 , the print height may be increased. There is no limit to the number of print cartridges (not shown) that may be used in inventive device  100 . 
   Each print mechanism  106  secures to one side of tractor frames  1  via two ¼-20 screws  111 . Print mechanism&#39;s  106  face (not visible) installs snugly against tractor skids  30 . Printing occurs through the open areas in tractor skids  30 , wherein ink jet nozzles on the print cartridge (not visible) face extend through the hole in tractor skids  30  such that they protrude until they are approximately flush with the inside surface of tractor skids  30 . Note that tractor skids  30  guide bag  200  as it travels through inventive device  100  during the printing operation. 
   Print height adjustment as well as calibration required to eliminate “stitching”, a condition that occurs when overlapping print nozzles are not coplanar, is accomplished by adjusting knobs  58 A and  58 B. Turning knobs  58 A and  58 B in the same direction allow print mechanism  106  to be raised or lowered +/−⅛″, or, by turning knobs  58 A and  58 B in opposing directions print mechanism  106  can be rotated +/−5° around the axis normal to the print plane. The latter adjustment compensates for misalignment by allowing print mechanism  106  to be rotated such that overlapping ink jet nozzles become coplanar, thusly eliminating stitching. Although not shown, an optional power assisted print head adjustment mechanism may replace manual knobs  58 A and  58 B. Additionally, a closed-loop feedback system may be used for automatic alignment of the print nozzles for the purpose of eliminating the stitching condition.