Abstract:
A printer with debris control apparatus which minimizes printer fouling. The printer includes a print head for printing on media, a platen having a side for feeding the media along a path past the print head, and debris control member in contact with the media.

Description:
BACKGROUND 
       [0001]    Perforation and folding of printable media cause unwanted debris in printers. Debris may include loose coatings, loose fibers, chaff, and dirt. In large enough amounts, this debris may contaminate print heads and drive platens during printing, resulting in print degradation, misfeeding of paper, and complete printer failure. It would be desirable to minimize debris as much as possible. 
       SUMMARY 
       [0002]    A printer with debris control apparatus is provided. 
         [0003]    The printer includes a print head for printing on media, a platen having a side for feeding the media along a path past the print head, and debris control member in contact with the media. 
         [0004]    In an example embodiment, the debris control member may include a fibrous material having a non-uniform surface and be located upstream of the print head along the path of the media for collecting the debris from the media. 
         [0005]    In another example embodiment, the debris control member may include a non-uniform surface on the side of the platen for repelling the debris. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  shows a schematic of an example printer. 
           [0007]      FIGS. 2A and 2B  show an example receipt from the printer of  FIG. 1 . 
           [0008]      FIG. 3  shows an example embodiment of a debris control apparatus. 
           [0009]      FIG. 4  shows another example embodiment of a debris control apparatus. 
           [0010]      FIG. 5  shows the schematic of  FIG. 1  modified to show the example debris control apparatus of  FIG. 4 . 
           [0011]      FIG. 6  shows a perspective view of an example printer. 
           [0012]      FIG. 7  shows a partial centerline elevation view of the example printer of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    By way of example, various embodiments of the invention are described in the material to follow with reference to the included drawings. Variation may be adopted. 
         [0014]    With reference to  FIG. 1 , example printer  10  may include a direct thermal printer. The illustrated printer  10  is useable for printing on two sides of thermal print media  20 . However, direct thermal printers which print only on one side of thermal print media  20  are also envisioned. 
         [0015]    Printer  10  includes rotating platens  30  and  40  and opposing thermal print heads  50  and  60  on opposite sides of thermal print media  20 . Direct thermal printing of thermal print media  20  may occur in a single pass at, for example, completion of a transaction such as when a receipt or ticket is issued. Alternately, direct thermal printing may occur in a two or more pass process where, for example, thermal print media  20  is imaged by one or both thermal print heads  50  and  60  when moving in a first direction, and then retracted for further imaging by one or both thermal print heads  50  and  60  with thermal print media  20  moving in either the first or a second, retract direction. Once printing is completed, thermal print media  20  may, depending on its format (e.g., roll, fan fold, individual sheets, and the like), be manually or automatically cut or severed to provide an individual receipt, ticket, or other document. 
         [0016]    Thermal print media  20  includes thermal paper, such a thermal paper having a cellulosic or polymer substrate sheet and heat sensitive dyes. Printing on opposite sides of thermal print media  20  can be facilitated by including a substrate sheet that is sufficiently thermally resistant to inhibit thermal printing on one side of thermal print media  20  from affecting coloration on the opposite side of thermal print media  20 . 
         [0017]    Thermal print media  20  may be supplied in the form of a paper roll, fan-fold stack, individual sheet and the like, upon which printing such as graphics or text, or both, may be printed on one or both sides of thermal print media  20 , to provide, for example, a voucher, coupon, receipt, ticket or other article or document. 
         [0018]      FIGS. 2A-2B  show a two-sided thermal document in the form of a receipt  80 . With reference to  FIG. 2A , receipt  80  includes transaction detail  90  such as issuer identification, time, date, line item entries and a transaction total printed on a first (front) side of receipt  80 . 
         [0019]    With reference to  FIG. 2B , receipt  80  includes custom information  100  printed on a second (back) side of receipt  80  contemporaneous with transaction detail information  90  printed on the front. For example, custom information  100  could include further or duplicate transaction information, a coupon (as shown), rebate or contest information, serialized cartoons, conditions of sale, document images, advertisements, security features, ticket information, legal information such as disclaimers, warranties and the like, or other information. Further, custom information  100  may be targeted based on recipient/purchaser identity, transaction data, transaction detail  90 , store inventory or specials, manufacturer inventory or specials, and the like, or randomly selected from a database of possible options, among other means. 
         [0020]    Returning to  FIG. 1 , printer  10  additionally includes a debris control apparatus  70 . Debris may include loose coatings, loose fibers, chaff, and dirt from thermal print media  20 . Debris control apparatus  70  may control debris in various ways. For example, debris control apparatus  70  may collect and trap the debris prior to printing for later removal during servicing. As another example, debris control apparatus  70  may repel the debris from print platens  30  and  40 , so that the debris may be carried out of printer  10  a little at a time by thermal print media  20 , with no damage to print heads  50  and  60 . 
         [0021]    In one embodiment, debris control apparatus  70  may include surface features of platens  30  and  40 . With reference to  FIG. 3 , an example embodiment of a platen  30  and  40  includes a non-uniform or textured surface  110 . An example type of non-uniform or textured surface feature is stippling  112 . 
         [0022]    Stippling  112  exposes minimal platen surface area to print media  20  during feeding of print media  20 . Stippling  112  is optimally minimized to reduce the amount of platen surface area that touches print media  20  so that platens  30  and  40  collect little or no debris. Debris remains with or attaches to print media  20  and is carried away systematically in undetectable quantities. 
         [0023]    Surface  106  may be coated with a repellent, such as polytetrafluoroethylene (PTFE) or silicon. By coating surface  110  with repellant, debris has a desire to stick more to the paper than to platens  30  and  40 . Adding repellants to textured surface  110  results in more effective debris control. 
         [0024]    In another embodiment, debris control apparatus  70  may include one or more wiping bars  120  located adjacent thermal print media  20 . 
         [0025]    With reference to  FIG. 4 , an example of wiping bar  120  includes a housing  130  containing wiping nip  140 . Housing  130  may be made of plastic. Wiping nip  140  may include felt or other materials with exposed fibers. Wiping nip  140  may include a non-uniform or textured contact surface  150 , for example, have peaks and values, to collect and trap debris. Finally, wiping nip  140  may be impregnated or coated with a cleaning additive, such as silicon, oil, alcohol, and wax. 
         [0026]    With reference to  FIG. 5 , wiping bars  120  are located upstream of print heads  50  and  60  to remove, collect, and trap debris. Wiping bars  120  may be located on opposite sides of thermal print media  20 . 
         [0027]    Advantageously, the cleaning additives may also serve as lubricants for the purpose of extending print head life. Print heads  50  and  60  may be made of silica glass, which comes into direct contact with print media  20 . Direct contact causes friction and drag which eventually wears away the silica. Lubrication from silicone, wax, and the like coming from the wiping bars extends the life of print heads  50  and  60  by reducing the overall friction. 
         [0028]      FIGS. 6-7  illustrate an example embodiment of printer  200  for point-of-sale (POS) terminal application. Printer  200  may include one or more embodiments of debris control apparatus  70 , including the embodiments illustrated in  FIGS. 3 and 5 . 
         [0029]    With reference to  FIG. 7 , printer  200  includes a print head  210 , a platen  220  and a guide platen  230  all coupled to a supporting arm or base structure  240 . Print head  210 , platen  220  and guide platen  230  are on one side of feed path  250  of thermal print media  20  taken off a supply roll  260 . 
         [0030]    Platen  220  may include non-uniform or textured surface  222 , including stippling  224 , as similarly illustrated in  FIG. 3 . 
         [0031]    Printer  200  may also or alternatively include wiping bar  235  with nip  237  and non-uniform or textured surface  239  as similarly illustrated in  FIG. 4 . 
         [0032]    Printer  200  further includes a print head  270 , a platen  280  and a guide platen  290  all coupled to a pivotable supporting arm or cover  300 , which pivots about a hinge line  310  to allow, for example, paper replacement and servicing. 
         [0033]    Platen  280  may include non-uniform or textured surface  282 , including stippling  284 , as similarly illustrated in  FIG. 3 . 
         [0034]    Printer  200  may also or alternatively include wiping bar  275  opposed to wiping bar  235  with nip  277  and non-uniform or textured surface  279  as similarly illustrated in  FIG. 5 . 
         [0035]    When arm  300  is in the closed position (as shown), thermal print media  20  may be engaged between print head  210  and opposed platen  280 , between print head  270  and opposed platen  220 , between opposed wiping bars  235  and  275 , and between guide platens  230  and  290 . Contact pressures with, and tension of, thermal print media  20  are maintained by, for example, spring loading of the various printer elements using springs  320 ,  330  and  340 . 
         [0036]    Printer  200  may further include a spring  350  for pivotable supporting arm or cover  300  to enable opening of the cover  300  at a controlled rate, and thereby avoid, for example, uncontrolled closing of cover  300  through force exerted on cover  300  via the acceleration of gravity. A sensor  360 , may further be provided to detect a paper out condition, and produce a signal which can be used to disable printing, notify a POS operator to replace the supply roll  260 , and the like. A sensor  360  may also be provided to identify regions of the media for printing, including identifying regions comprising sense marks or other preprinted material. 
         [0037]    Printer  200  may further include an electronically activated mechanical cutting or knife blade mechanism  370  to sever the print media upon completion of a print task such as printing of a transaction receipt. A serrated edge  380  may also be included to enable manual severing of the print media at the end of a transaction, when a media print roll is replaced or reloaded, and the like. 
         [0038]    Printer  200  further includes control electronics for controlling operation of the printer  200 . The control electronics may include a motherboard  390 , a microprocessor or CPU  392 , and memory  394 , including one or more DRAM and/or NVRAM print buffer memory elements. Printer  200  further includes a communications port  396  for communicating with one or more host or auxiliary systems such as a POS terminal for input of data to, and output of data from, printer  200 . 
         [0039]    Communication controller  396  may support RS-232 serial, parallel, universal serial bus, Ethernet and/or wireless communications (e.g., 802.11, 802.15, and IR), among others. Data for printing would typically be supplied by a host POS terminal communicating with printer  200  via communication controller  396 . Supplemental data for printing, such as product and or discount coupon information can also be supplied by, for example, a network server providing data directly to printer  200  using the communication controller  396 , or indirectly through the host POS terminal. The supplemental data for printing may vary depending upon the goods or services sold, an in-store, chain-wide or manufacturer special, identification of the customer, and/or one or more other transaction aspects. 
         [0040]    Although particular reference has been made to certain embodiments, variations and modifications are also envisioned within the spirit and scope of the following claims.