The invention relates to thermal printer cartridges.
A thermal printer prints images by transferring donor material from a donor ribbon onto a receiver medium. Typically, this is done by selectively heating the donor ribbon to melt donor material while concurrently pressuring the donor ribbon against the receiver medium. In this way, melted donor material transfers from the donor ribbon to the receiver medium to form an image while unmelted donor material remains on the donor ribbon. Upon initial transfer to the receiver medium, donor material is often liquid and hot. Within a short period of time, the donor material enters a transition or glassy state. After a longer period of time, the donor material solidifies forming a permanent record on the receiver medium. The donor ribbon and receiver medium are separated after transfer of the material to yield a receiver medium having a pattern of deposited donor material forming an image.
Donor ribbon is typically connected between a supply spool, which initially carries a supply of unused donor ribbon, and a take-up spool upon which used donor ribbon is wound. In operation, the take-up spool is rotated to draw donor ribbon from the supply spool and across the print head for use in printing.
Often the donor spool and take-up spool are joined together by a structural framework to form a thermal donor cartridge. This structural framework positions the supply spool and the take-up spool in a preferred geometric relationship to facilitate proper loading and can also be used to provide surfaces that enclose or otherwise protect the donor ribbon from damage due to incidental contact and from damage due to exposure to contaminants.
It will be appreciated that there are a wide variety of thermal printers that use thermal donor cartridges. Typically, each donor cartridge is adapted for use in one specific thermal printer. Accordingly, there are a wide variety of donor cartridges. For example, the conveyance system used to position the receiver medium can take any of several different forms depending on the type of printer. Some thermal printers use dual pinch roller receiver systems that enable a compact printer to create an image without white borders on the print. Other thermal printers use channel systems to move receiver medium during printing. Such channel systems enable an extremely low cost printer. Still other thermal printers use drum systems to move receiver medium during printing. Such drum systems have the potential for good color registration yet at a fairly large size on the desktop.
Thermal printers that use donor cartridges typically provide for printhead articulation so as to allow the printhead to be moved to a secure location during loading and unloading of the donor cartridge. Here too, a variety of approaches can be used to provide such printhead articulation. For example, small pivot head arms typically mate with drum type thermal printer systems while a long lever arm that pivots outside the distance of the spools is often used in roller receiver systems. Accordingly, the design of a thermal donor cartridge will typically be adapted to reflect this. Additional considerations and accommodations are made in thermal printer cartridges to facilitate the movement of donor ribbon so as to minimize donor ribbon wrinkle and other related problems.
Further, there are significant differences in the way in which donor ribbon is used in thermal printers. More specifically, many thermal printers are designed to separate donor ribbon from the receiver medium while the donor material is hot and is still in a liquid or molten state while other thermal printers separate the donor ribbon from the receiver medium only after the receiver medium has cooled for example to a solidified state. However, the donor cartridges that are designed for use in thermal printers that separate the donor web from the receiver medium while the donor material is hot are typically not compatible with donor cartridges that are designed for use in thermal printers that separate the donor web from the receiver medium when the donor material has cooled. Largely, this is because the latter printers require donor cartridges that are sized and shaped to allow the donor ribbon and receiver medium to travel in concert after printing to allow for cooling while the former printers separate the donor ribbon from the receiver medium soon after printing.
Because of these differences in thermal printers, a thermal donor cartridge is typically adapted for use in one printer and is rarely useful in different thermal printers. Accordingly, it is also known to provide donor ribbon in the form of a matched pair of donor spools and take-up spools that are joined only by the donor ribbon. Such an arrangement of donor ribbon allows the donor ribbon to be used in a variety of different printers in that the take-up and supply spools can be positioned at any distance relative to each other and in that such an arrangement imposes no inherent limitations on the path that the donor ribbon must take as it passes from the supply spool to the take-up spool. However, a person installing such donor ribbon in a thermal printer must exercise skill in handling and loading the donor ribbon to ensure that the spools and the donor ribbon are properly threaded through the donor ribbon travel path in the printer and must also use a care to ensure that the donor ribbon is not damaged, altered or contaminated.
What is needed in the art therefore is a low cost thermal printer cartridge that can be used with a wide variety of thermal printers.
In one aspect of the invention a cartridge is provided. The cartridge has a donor ribbon having sets of different donor material patches thereon; a supply housing having at least one exterior surface defining a supply area shaped to position a supply spool for rotation about a supply axis, said supply spool being connected to one end of a supply of donor ribbon, with the supply housing further having a supply projection extending away from the at least one of the exterior surface of the supply housing, said supply projection allowing the donor ribbon to pass from the supply area to a supply waypoint, and a take-up housing having at least one exterior surface defining a take-up area shaped to position a take-up spool for rotation about a take-up axis, said take-up spool being connected to another end of the donor ribbon, with the take-up housing having a take-up projection extending away from the at least one exterior surface of the take-up housing said take-up projection allowing the donor ribbon to pass from a take-up waypoint to the take-up area. A connecting portion holds the supply housing and the take-up housing apart on a common side of the connecting portion to form a separation area therebetween, said connecting portion providing a printing path from the supply waypoint to the take-up waypoint, wherein the arrangement of the supply projection, take-up projection and connecting portion further position the supply waypoint at supply side separation from supply housing and position the take-up waypoint at a take-up separation from the take-up housing.
A supply projection 27 is connected to lower exterior surface 26 and extends away from lower exterior surface 26 to allow donor ribbon 42 to pass from supply area 28 to a supply waypoint 29. As is illustrated in
Thermal donor cartridge 20 also has a take-up housing 52 with a drive end 53 and a non-drive end 54. In the embodiment illustrated, take-up housing 52 is shown having an upper exterior surface 55 and a lower exterior surface 56 that define a take-up area 58. Bearing surfaces 60 and 62 are provided by take-up housing 52 and are adapted to receive a take-up spool 68 that is connected to donor ribbon 42.
A take-up projection 57 extends away from lower exterior surface 56 to allow donor ribbon 42 to pass from a take-up waypoint 59 to take-up area 58. As is illustrated in
Supply housing 22 and take-up housing 52 are joined to and are held apart on a common side 71 of a connecting portion 70 to form a separation area 74 therebetween along a length of thermal donor cartridge 20. In the embodiment illustrated in
Access window 76 allows printing structures to contact donor ribbon 42 so that at least a portion of donor ribbon 42 positioned along printing path 78 can be used for printing without substantially removing donor ribbon 42 from thermal donor cartridge 20. In practice this typically means that a thermal printhead (not shown) can be advanced against a top surface of donor ribbon 42 to drive donor ribbon 42 against a receiver medium (not shown) that is supported by a platen (not shown).
In this embodiment, supply waypoint 29 takes the form of a surface, which can be a stationary surface such as an edge of supply projection 27, a bar (not shown) or a rotating surface such as a shaft (not shown) around which donor ribbon 42 turns to enter a printing path 78. Printing path 78 extends from supply waypoint 29, through access window 76 to take-up waypoint 59. Donor ribbon 42 turns at take-up waypoint 59 for travel through take-up projection 64 to take-up area 58. Take-up waypoint 59 can be a stationary surface such as an edge of take-up housing projection 57, a bar (not shown) or a rotating surface such as a shaft (not shown) around which donor ribbon 42 turns while exiting printing path78.
In this way, thermal donor cartridge 20 provides a donor ribbon path that flows from supply housing 22, along supply projection 27, to supply waypoint 29 through connecting portion 70 along a printing path 78 to take-up waypoint 59, along take-up projection 57 and into take-up housing 52. Any of these structures can provide surfaces that contact donor ribbon 42 and that can be used as donor ribbon guides leading the donor ribbon 42 from supply housing 22 through supply side edge 90 of access window 76 to a take-up side edge 92 of access window 76 and to take-up housing 52. Accordingly, such donor ribbon guides can comprise the donor path.
In the embodiment illustrated in
It will be appreciated that in other embodiments, supply-housing 22, take-up housing 52, and connecting portion 70 can be formed using more or different components and using different assembly techniques.
As can be seen in
Printing path 78 extends along a horizontal length K from supply waypoint 29 to take-up waypoint 59. Access window 76 extends along a horizontal length C of thermal donor cartridge 20 from a supply side edge 90 to a take-up side edge 92 of access window 76.
As is also shown in
Similarly, the arrangement of take-up housing 52, take-up projection 57, and connecting portion 70 position take-up waypoint 59 at a take-up side waypoint offset G measured along a take-up axis 96 from supply waypoint 59 to take-up spool axis 96, while lower exterior surface 56 of take-up housing 52 is positioned at a take-up housing offset H measured along take-up axis 96. As is shown in
In some embodiments of thermal donor cartridge 20, a ratio of the supply side waypoint offset distance D to the supply side housing offset distance E is between about 1.3 to 1.9, while in other embodiments this ratio can be between about 1.5 to 1.75. Further, in certain embodiments of thermal donor cartridge 20 a ratio of take-up waypoint offset distance G to take-up side housing offset distance H (G/H) is within a range of about 1.6 to 2.5 while in other embodiments, this ratio can be between about 1.70 to 1.90. Additionally, a ratio of spool separation distance A to the sum of the length of access window C plus the supply waypoint offset distance D plus the take-up waypoint offset distance G (A/(C+D+G) is between about 0.5 to 0.95.
As is also illustrated in the embodiment of
In such a print area 120 of dual capstan type of printer, receiver medium 150 is moved past thermal printhead 122 and platen 124 by gripping receiver medium 150 with one or the other of two pairs of motorized pinch rollers. In the embodiment of
As shown in
As is also shown in
Using this method, such pinch roller pairs can held close to a nip between the thermal printhead 122 and platen 124 in order to minimize the receiver length between them. This minimizes the unsupported travel distance of receiver medium 150 during printing so that the beam strength stiffness of receiver medium 150 is maximized during printing. It will be appreciated that the stronger the beam strength of this portion of receiver medium 150 during printing, the less likely that it is that receiver medium 150 will buckle during printing thus reducing the risk of mis-registration and other errors that can arise.
As is shown in
It will be appreciated that where a thermal donor cartridge 20 is used in a print area 120 that uses a structure such as printhead positioning mechanism 130 it is useful for thermal donor cartridge 20 to be shaped to permit pivot arm 130 (or any other printhead positioning system) to move thermal printhead 122 between a printing position and a non-printing position which. Accordingly, in embodiments where such use is desired, thermal donor cartridge 20 can have a donor perimeter extension length M (not illustrated) that is defined to enable a pivot arm 132 that pivots about pivot 134 to be positioned outside a perimeter of thermal donor cartridge 20 so that pivot arm 132 can move a printhead that is within separation 74 between a printing position and a non-printing position. In this embodiment, this is done by providing a donor perimeter extension length M that is sum of an available loop for a thermal print head to engage donor ribbon 42 where M is determined as the sum of one half the access length B, the take-up waypoint offset distance D and the take-up offset distance E.
As is also illustrated in
Printhead 122 is movable between a loading position illustrated in
It will be appreciated that the separations F and J used to make thermal printer cartridge 20 useful in a dual capstan type printer of the type illustrated in
It will be appreciated that in any of the above described embodiments, a supply projection 27 can be shaped so that the supply projection 27 enables an upper supply side pinch roller 142 to be positioned proximate to the supply waypoint 29.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
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4978240 | Katsuno | Dec 1990 | A |
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3742337 | Jun 1989 | DE |
0 294 792 | Aug 1991 | EP |
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0 857 580 | Apr 2003 | EP |
05-169778 | Jul 1993 | JP |
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Number | Date | Country | |
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20080002013 A1 | Jan 2008 | US |