Patent Publication Number: US-6341837-B1

Title: Ink-jet printer having a waste ink collecting box

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled A Waste Ink Collection Box for Ink Jet Printer earlier filed in the Korean Industrial Property Office on Jul. 31, 1999, and there duly assigned Serial No. 99-31550 by that Office. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to ink-jet printers, and more particularly, to an ink-jet printer that is capable of uniformly spreading waste ink, which is discharged from its ink cartridge, in its waste ink collecting box. 
     2. Description of the Related Art 
     In general, an ink-jet printer is a nonimpact printer that forms images by having jets of ink broken up into electrostatically charged drops. According to the input data, the electrostatically charged drops are guided into positions that form images and characters on a paper or other printable medium. As a print head moves across the surface of the paper, it shoots a stream of tiny, electrostatically charged ink drops from an ink cartridge at the page to form the image. A container within the ink-jet printer collects waste ink that is discharged just before a printing process. The hardened ink on the nozzles of the ink cartridge is removed and deposited in the waste ink container. 
     The collection of ink is not, however, always uniform. The nozzles come in contact with the ink from the waste ink container because the ink, especially black ink, accumulates towards the nozzle in the waste ink container. Inks such as black ink pile up in the waste ink container because it dries into a gel state. The nozzles becomes contaminated or even clogged by the waste ink. The quality of the print is greatly reduced because of the accumulation of the ink in the waste ink container. 
     The exemplar art of U.S. Pat. No. 5,801,725 for Slidable Wiping and Capping Service Station for-Ink Jet Printer issued to Neese, et al., U.S. Pat. No. 5,946,009 for Service Station for Ink-jet Printer issued to Youn, U.S. Pat. No. 4,524,365 for Receptacle for Waste Ink Collection in Ink Jet Recording Apparatus issued to Kakeno, et al., U.S. Pat. No. 4,901,094 for Waste Collecting Device of an Ink Jet Printer issued to Iwagami, et al., U.S. Pat. No. 5,221,935 for Waste Ink Receiving Cartridge and Ink Recording Apparatus Using said Cartridge issued to Uzita, U.S. Pat. No. 5,953,026 for Ink Jet Printing Apparatus, Method of Disposing Waste Liquids and Apparatus Therefor issued to Yoshino, U.S. Pat. No. 4,965,596 for Ink Jet Recording Apparatus with Waste Ink Distribution Paths to Plural Cartridges issued to Nagoshi, et al., and U.S. Pat. No. 5,329,306 for Waste Ink Separator for Ink Jet Printer Maintenance System issued to Carlotta disclose waste ink separators in ink-jet printers. I have found that the art does not show an efficient method and apparatus that uniformly spreads ink in a waste ink collecting box of an ink-jet printer. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide to an ink-jet printer that is capable of uniformly spreading waste ink, which is discharged from an ink cartridge, in a waste ink collecting box. 
     It is another object to improve the servicing of the print head without reducing printing efficiency. 
     It is still another object to prevent the print head from being contaminated or clogged. 
     It is yet another object to increase the print quality of an ink-jet printer. 
     It is another object to increase the life span of an ink-jet cartridge. 
     In order to accomplish the above object, the present invention provides an ink-jet printer, having a frame, a paper feeder is mounted on one side and on the other side a discharge device is mounted; a carriage that has at least one ink cartridge loaded, the carriage being transversely reciprocated between a printing area and a service area along a guide rod that is horizontally mounted to the frame; a waste ink collecting box for collecting waste ink discharged from the ink cartridge in the service area; and a device for uniformly spreading the waste ink heaped in the waste ink collecting box. 
     Preferably, the waste ink spreading device may have a waste ink spreader, the waste ink spreader having a hinge portion rotatably mounted to the waste ink collecting box, a spreader arm extended from one side of the hinge portion, the spreader arm spreading heaped waste ink uniformly in the waste ink collecting box, and a spreader head extended from the opposite end of the hinge portion, the spreader head being actuated for rotation of the spreader arm. 
     Preferably, the waste ink spreading device may further comprise a spring that is secured to the waste ink collecting box and the spreader head of the waste ink spreader at both its ends. Preferably, the spreader head may be actuated by movement of the carriage. In particular, the waste ink spreading device may further have a pusher that is projected from the service area side of the carriage, the pusher actuating the spreader head to rotate the waste ink spreader. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of this invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
     FIG. 1 is a perspective view of an ink-jet printer; 
     FIG. 2 is a perspective view of an ink-jet printer in accordance with the present invention; 
     FIG. 3 is a perspective view showing a waste ink collecting box and waste ink spreading device that are combined with each other; 
     FIG. 4 is an exploded view showing the waste ink collecting box and the waste ink spreading device that are separated from each other; and 
     FIGS. 5A to  5 C are plan views showing the operation of the waste ink spreading device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to the drawings, referring to FIG. 1, an ink-jet printer has a frame  10 . A lower plate  21  is secured to the bottom of the frame  10 . A paper feeder  11  is mounted to the rear portion of the frame  10 , and a discharge roller  12  is mounted to the front portion of the frame  10 . A printing unit is mounted in the frame  10 . The printing unit has a guide rod  13  that is horizontally positioned, a carriage  14  that is slidably fitted around the guide rod  13 , and a color ink cartridge  15  and a black ink cartridge  16  that are loaded on the carriage  14 . 
     A driving device is provided so as to forcibly move the carriage  14  transversely. The driving device has a driving motor  17  that is mounted to one side of the rear portion of the frame  10  and a drive belt  18  that is driven by the drive motor  17  and securely connected to the rear portion of the carriage  14 . 
     The interior area of the frame  10  may be divided into a printing area in which the carriage  14  is moved transversely while actual printing is performed and a service area in which the carriage  14  is retreated while actual printing is not performed. In particular, wipers  19  and sealing caps  20  are mounted in the service area of the frame  10 . The wipers  19  serve to remove remaining ink and dirt that adhere to the nozzles of the ink cartridges  15  and  16  and the sealing caps  20  serve to enclose the nozzles of the ink cartridges  15  and  16  and prevent ink from being hardened on the nozzles of the ink cartridges  15  and  16 . 
     A waste ink collecting box  22  is disposed on the lower plate  21  at a position under the service area. The waste ink collecting box  22  serves to collect waste ink that is discharged just before a printing process so as to supply superior ink by removing hardened ink from the nozzles of the ink cartridges  15  and  16 . Therefore, the waste ink that is discharged from the ink cartridges  15  and  16  is collected in the ink collecting box  22 . As shown in the drawing, the ink collecting box  22  is in the form of a box open at its top and integrated with the bottom plate  21 . 
     Meanwhile, of the waste ink that is collected in the waste ink collecting box  22  of the conventional ink-jet printer, waste black ink collected from the black ink cartridge  16  experiences a phase change from a liquid phase to a gel phase while being exposed to the atmosphere. Consequently, the waste black ink collected in the waste ink collecting box  22  is not spread uniformly on the bottom of the ink collecting box  22 , but is heaped toward the nozzles of the ink cartridges  15  and  16 . In this case, since the heaped waste ink comes into contact with the nozzles of the cartridges  15  and  16 , the nozzles of the ink cartridges  15  and  16  are contaminated or stopped up by the waste ink, thereby hindering the printing operation of the printer. 
     As illustrated in FIG. 2, an ink-jet printer of the present invention has a frame  100  to which the components, described below, are mounted and a lower plate  210  that is secured to the bottom of the frame  100 . Although not shown, a case may be placed on the frame  100 . A paper feeder  110  is mounted to the rear portion of the frame  100  so as to supply printing paper, and a discharge roller  120  is mounted to the front portion of the frame  100  so as to discharge printed papers. A printing unit is mounted in the frame  100 . The printing unit has a guide rod  130  that is horizontally mounted to the frame  100 , a carriage  140  that is slidably fitted around the guide rod  130 , and a color ink cartridge  150  and a black ink cartridge  160  that are loaded on the carriage  140 . 
     A driving device (reference numeral not assigned) is provided so as to forcibly move the carriage  140  transversely. The driving device has a drive motor  170  that is mounted to one side of the rear portion of the frame  100 . A drive belt  180 , driven by the drive motor  170 , is securely connected to the rear portion of the carriage  140  and uniformly spaced apart from the guide rod  130 . 
     The interior area of the frame  100  may be divided into a printing area and a service area. The printing area is where the carriage  140  is moved transversely while actual printing is performed and the service area is where the carriage  14  is retreated while actual printing is not performed. In particular, wipers  190  and sealing caps  200  are mounted in the service area of the frame  10 . The wipers  190  serve to remove remaining ink and dirt that adhere to the nozzles of the ink cartridges  150  and  160 , and the sealing caps  200  serve to enclose the nozzles of the ink cartridges  150  and  160  and prevent ink from being hardened on the nozzles of the ink cartridges  150  and  160 . 
     A waste ink collecting box  220  is disposed on and integrated with the bottom plate  210  in the form of a rectangular plate at a position under the service area. In accordance with the present invention, a waste ink spreader  500  is mounted to the waste ink collecting box  220  so as to uniformly spread heaped waste ink that is discharged from the nozzles of the black ink cartridge  160 , in the waste ink collecting box  220 . 
     The capacity of the waste ink collecting box  220  for containing waste ink is designed to coincide with the amount of waste ink that is generated during the life span of the ink-jet printer. If waste ink is not spread uniformly in the waste ink collecting box  220 , the heaped waste ink comes into contact with the nozzles of the ink cartridges  150  and  160  and overflows the waste ink collecting box  220 , after a lapse of a certain time period and before the termination of the life span of the ink-jet printer. 
     In the case of color ink, the heaping of waste ink does not occur because the waste color ink is low in its viscosity. However, in the case of black ink, the heaping of waste ink occurs because the waste black ink is high in its viscosity and easily hardened in the atmosphere. 
     The waste ink spreader  500  prevents waste ink from accumulating by being situated directly under the ink-discharged portion of the waste ink collecting box  220  and uniformly spreading the waste ink in the waste ink collecting box  220 . 
     Referring to FIGS. 3 and 4, a pivot  230  is vertically formed on the bottom portion of the waste ink collecting box  220  at a position where the waste black ink is discharged from the black ink cartridge  160 . The waste ink spreader  500  has a rotating sleeve  520  that is rotatably fitted around the pivot  230 , a spreader arm  510  horizontally extended from one side of the sidewall of the rotating sleeve  520 , a gooseneck portion  530  and  540  that is horizontally extended from the opposite side of the sidewall of the rotating sleeve  520 , and a spreader head  550  that is integrated with the outer end of the gooseneck portion  530 . The spreader arm  510  is in the form of a plate and extended from the pivot  230  to a certain extent. 
     The gooseneck portion  530  and  540  is bent two times. The first bend  530  is horizontally extended along the bottom of the waste collecting box  220  and bent upward, and the second bend  540  is vertically extended from the first bend  530  along the wall of the waste collecting box  220  and bent sideward. 
     The spreader head  550  is in the form of a short right-triangular prism, and is extended from the outer end of the gooseneck portion  540  with its oblique surface  550   a  forming its inside wall. The oblique surface  550   a  of the spreader head  550  is arranged to form a certain angle with the pusher  140   a  so that the pusher  140   a  can be slid upon the oblique surface  550   a . The height of the spreader head  550  is designed to correspond with the height of the carriage  140 . 
     Two spring hooks  240  and  550   b  are respectively mounted to the sidewall of the waste ink collecting box  220  and the lower edge of the oblique surface  550   a  of the spreader head  550 . A spring  560  is caught on the spring hooks  240  and  550   b  at its ends. 
     Meanwhile, referring to FIG. 2, a pusher  140   a  is horizontally projected from the service area side of the carriage  140  so as to rotate the spreader head  550 . A pusher hole  100   a  is formed on a sidewall of the frame  100  so that the pusher  140   a  passes through the pusher hole  100   a  and pushes the spreader head  550 . The spreader head  550  has an oblique surface that is arranged to form a certain angle with the pusher  140   a.    
     The operation of the printer of the present invention is described hereinafter with an emphasis laid on the operation of the waste ink spreading device. 
     After a sheet of paper is fed by the paper feeder  10  into the printing area, a printing process is performed while the drive motor  170  moves the carriage  140  transversely. Before actual printing is initiated, the carriage  140  is situated in the service area and the nozzles of the ink cartridges  150  and  160  are enclosed with the sealing caps  200 . 
     Just before actual printing is initiated, the nozzles of the cartridges  150  and  160  are removed from the sealing caps  200  and a small amount of ink is discharged from the ink cartridges  150  and  160  into the ink collecting box  220 . As described above, this is for achieving a high quality of printing by discharging hardened ink in the outlets of the nozzles in advance of performing actual printing. 
     After the advanced discharge of the ink is performned, the carriage  140  performs actual printing while being moved transversely and the nozzles of the ink cartridges  150  and  160  are swept by the wipers  190 . 
     Hereinafter, the operation of the waste ink spreading device is described. 
     FIG. 5A is a plan view showing the state of the waste ink spreader  500  while the actual printing is performed. In this state, the front end of the spreader arm  510  is situated in the vicinity of the front wall of the waste ink collecting box  220 . 
     As shown in FIGS. 5B and 5C, when the carriage  140  is returned to the service area after actual printing, the pusher  140 a projected from the carriage  140  pushes the oblique surface  550   a  of the waste ink spreader  550 . As a result, as the force exerted by the pusher  140   a  overcomes the force of the spring  560 , the spreader arm  510  and the spreader head  550  are rotated around the pivot  230  clockwise. In this state. the front end of the spreader arm  510  is situated in the vicinity of the rear wall of the waste ink collecting box  220 . 
     When the carriage  140  is moved to the printing area for new actual printing, a small amount of ink is discharged from the nozzles of the ink cartridges  150  and  160  just before the actual printing. In the meantime, as the carriage  140  is moved to the printing area, the spreader arm  510  and the spreader head  550  are rotated around the pivot  230  counterclockwise by the restoring force of the spring  560 . During the counterclockwise rotation of the spreader arm  510 , heaped waste ink  504  is spread uniformly in the waste ink collecting box  220  by the spreader arm  510 . Finally, the waste ink spreader  500  is situated as shown in FIG.  5 A. 
     As described above, the present invention provides an ink-jet printer that is capable of uniformly spreading the heaped waste ink in its waste ink collecting box, thereby preventing the nozzles of its ink cartridges from being contaminated or stopped up and preventing waste ink from overflowing the waste ink collecting box due to the heaping of the waste ink. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.