Typewriting machines – Including plural – independently supported key-boards,...
Utility Patent
1999-10-01
2001-01-02
Hilten, John S. (Department: 2854)
Typewriting machines
Including plural, independently supported key-boards,...
C400S120050
Utility Patent
active
06168324
ABSTRACT:
This application is the national phase of international application PCT/GB98/00286 filed Jan. 30, 1998 which designated the U.S.
FIELD OF THE INVENTION
The invention relates to thermal transfer printers, and especially to thermal transfer printers useful for service in photo booths.
BACKGROUND TO THE INVENTION
Thermal transfer printing is a process for generating printed images by transferring thermally transferable colorant from a thermal transfer donor sheet to a receiver. Donor sheets comprise a base film coated on one side with a transfer coat, the latter comprising either a non-transferable binder containing one or more thermally transferable dyes for dye diffusion or sublimation transfer, or an ink of colorant and fusible binder which also transfers with the colorant. Printing is effected by heating selected areas of the donor sheet while the transfer coat is pressed against the surface of the receiver, thereby to transfer the dyes or inks from those selected areas to corresponding areas of the receiver. This generates an image according to the areas selected. Being a dry process not requiring any reagent solutions, thermal transfer printing is particularly suited to occasional unsupervised operation in stand-alone photo booths.
At present the most common form of thermal transfer printer uses a thermal head with a row of tiny heaters to heat the selected areas while the donor sheet and receiver sheet are pressed together between the thermal head and a platen in the form of a roller. The areas to be heated are selected by electronic control of the heaters (e.g. according to a video-or computer-generated image signal), as the donor sheet and receiver are progressed between the thermal head and the platen, line by line. Clear, high resolution images can thus be built up.
By repeating the transfer process with each of the three primary colours, full colour images can be obtained. Donor sheets are normally in the form of long ribbons, having repeated sequences of print size panels of each primary colour and any other materials to be transferred, such sequence being repeated along the ribbon to enable it to be used for as many prints as there are repeats of the sequence. The majority of dye diffusion which are loaded as a stack of pre-cut receiver sheets to be fed to the printhead in turn, as required for printing. However, such printers are not well adapted for general use in photo booths and other applications where customer-initiated automated operation is required.
It is a primary aim of the present invention to provide a thermal transfer printer which is more adaptable for use in various aspects of photo booths.
THE INVENTION
According to the invention, there is provided a thermal transfer printer comprising:
(a) means to receive an electronic image signal;
(b) first and second parallel and adjacent print engines, each engine comprising a platen roller, means to hold a donor ribbon set comprising a donor ribbon extending from a supply spool to a take-up spool, means to hold a supply of receiver sheet, and drive means to rotate the platen roller and to transport the donor ribbon and receiver sheet through the engine during printing independently from the drive means of the other engine;
(c) a printhead having a first set of heaters being positioned to operate with the first engine and a second set of heaters being positioned to operate with the second engine; and
(d) a control means to coordinate activation of the drive means of one of the engines selectively with application of the image signal to the heater set which is operable with that selected engine.
The two sets of heaters are preferably incorporated in a single row extending across both engines.
Because both engines can be operated independently, the printer can be set up for independent or dual printing. The latter is particularly advantageous where multiple copies of the same image are required without undue delay. Typically, two full-colour A6 prints may take 1½minutes to produce sequentially, and such delay can be tiresome for customers and unhelpful in heavily used printers. Where such multiple applications are required, a preferred printer is one wherein the control means can be set up to direct the image signal to both sets of heaters while activating the drive means of both engines simultaneously. The print time may then be halved to about 45 seconds.
However while operation in this mode may be advantageous for speeding up heavily used photo booths other benefits can accrue by setting up the control means to direct the image signal to one set of heaters only, and correspondingly activating only the drive means of the engine with which that set of heaters is operable. One or other engine may then be selected according to the nature of the media installed. For example the two engines may be loaded with receiver sheets having different formats or preformed security marks, e.g. for providing prints for different applications such as passports, driving licences or security passes having different requirements, or one engine may be loaded with black donor ribbon, while the other has a ribbon for providing full colour prints. These options may be selected by the control means in response to a manual input, such as a security code, for example. None of these facilities can be achieved in a conventional printer as described in the background section above.
In all such instances where the printer is set up to produce prints from both engines simultaneously or to select one or other engine according to requirements, the printer ceases to function in the manner expected when the media loaded into either engine becomes used up. Also the operator would need to waste partially used media or try to make the service call coincide with the media finish. It is therefore preferred to set up the printer in this manner only where the booths are located in the operator's place of business, or otherwise such that immediate attention can be given in the event of such stoppage. Such problems (which also would be suffered by the above-described conventional printers without the present benefits) may otherwise be alleviated to some extent by frequent operator inspection.
Unfortunately, stand-alone photo booths tend to be set up in locations remote from their operators, and are expected to work unsupervised between media replenishments. Furthermore each operator's various booths may be scattered with a wide geographical spread. Where the printers are to be installed in such remote photo booths it is preferred to use printers according to the invention wherein the control means is connected to detectors to sense the status of at least one of the donor sheet and receiver sheet supplies for both engines, and wherein the control means is responsive to a detected status in determining which set of heaters to select for receiving the image signal and correspondingly which drive means to activate. The status of a media supply and the manner of its being sensed can be various. Thus for example a detector may be used which senses movement of the donor sheet or receiver sheet, or more specifically senses lack of such movement when it is expected during printing, and thereby indicates a jam or other malfunction, such that the control means responsive to such information may switch the printing to the other engine to await the next visit by the operator.
A more generally preferred printer having such features is one wherein each engine has a detector to sense the depletion of at least one of the donor ribbon supply and the receiver sheet supply, and, responsive to sensing such media-depletion in one engine, the control means activates the drive means of the other engine and directs the image signal to the set of heaters operative with that other engine. This increases the overall reliability of the photo booth and allows more efficient use of media, because each time, the operator replenishes it he can replace the fully used media in one print engine and leave the partially used media in the other engine until that similarly bec
Goddard Kent C
Lever Philip E
Portus Robert T
Chau Minh
Hilten John S.
Imperial Chemical Industries plc
Pillsbury Madison & Sutro LLP
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