EP0645251A1

EP0645251A1 - Storage of thermal transfer printer media information with media, in compressed form, and subsequent retrieval of the stored information

Info

Publication number: EP0645251A1
Application number: EP94114495A
Authority: EP
Inventors: Mark Allan C/O Eastman Kodak Co. Bobb
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1993-09-27
Filing date: 1994-09-15
Publication date: 1995-03-29
Also published as: JPH07172024A

Abstract

A method of storing and retrieving information with a consumable thermal transfer printer medium, wherein medium information to be associated with a thermal transfer printer medium is compressed and stored in physical association with the thermal transfer printer medium. The information compression may be by data compression means (which may or may not be adaptive), by error correction code means, or other suitable means; with or without an error correction code, and with or without encrypting. The information may be stored on the thermal transfer donor medium, on the thermal transfer receiver medium, on a label adhered to the medium, or on accompanying structure such as a spool or cassette.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to thermal printing such as thermoplastic transfer printing or thermal dye transfer printing, and more particularly to such printing systems which use consumable media such as donor medium and/or receiver medium.

2. Description of the Prior Art

Thermal printers selectively heat the elements of a print head to transfer dyes and inks from a donor medium to a receiver medium. Thermoplastic transfer printers have a donor medium that includes a meltable wax which is impregnated with colored pigments or inks. Portions of the wax layer are heated to a liquid state, and are transferred with the color pigments or inks to a receiver medium. Thermal dye transfer printers have a donor medium which carries a dye that is transferred to a receiver by a sublimation process. The amount of dye transferred is generally controlled by the amount of energy supplied to an individual element. A typical print head includes a plurality of selectively operable resistive heat elements.
Receiver media are available in several types optimized for a variety of applications including reflection prints and transparencies. Similarly, donor media come in several types, such as monochrome or color. A typical thermal printer adjusts the energization of the print head based upon the type of donor and receiver media used to achieve an acceptable print quality. Thermal printers typically determine the type of media present in the printer by detecting information which may be marked directly on the media or on structures associated with the media such as a spool or cassette.
Detection marks frequently convey information which identifies the media, provides positional information on the media, and also can provide additional helpful information. Examples of identification information include manufacturer, logo or trademark, media type or application, lot number, size of media, number of prints, number and/or sequence of colors, size of frame, and printing correction factors. Positional information may include side of media (front or back), beginning of media, beginning of frame, beginning of color patch, end of media, end of frame, initial print position, and direction (forward or reverse). Additional information may be included in detection marks, such as number of frames remaining, color of frame, quality of frame, printing sequence of frames, dye sensitivities, and change in dye sensitivities. Other kinds of information may also be included in the detection marks.
One method a printer uses to determine how to energize the print head is by detecting information stored in a detection mark on the dye donor and/or dye receiver. After decoding the detection mark, the printer selects appropriate print head energization parameters suited to the media present from a plurality of stored parameters tables.
In conventional detection marking methods, the amount of information which can be stored in the detection mark is quite limited. For example, the amount of information which can be stored in a bar code or similar detection mark is limited by the number of lines the code includes.
To overcome this limitation, a multiplicity of tables containing print head energization parameters are frequently stored in the printer. At least one table is provided for each combination of dye donor and dye receiver which the printer can use. The number of tables which can be stored in a printer is limited by the amount of memory which the printer has. As the amount of memory increases, so does the complexity and cost of the printer hardware. Therefore, this method of storing print head energization parameters permanently in a printer has a limited usefulness.
Some other problems arise from this method of determining energization parameters for the print head. The first issue is lot-to-lot variation within a particular media formulation. The optimum performance characteristics of both donor media and receiver media vary from manufacturing lot to manufacturing lot. Thus, the tables of energization parameters stored in the printers must cover a range of performance characteristics, resulting in less than optimum performance for most lots of media.
A second issue is a long range problem. The formulations of the dye donor or dye receiver may change with time, or new formulations may be developed. To extend the usefulness of the printer, it would be highly desirable if the printers' energization parameter tables could be modified or adjusted. However with current printer designs it is difficult and expensive to modify these parameter tables once the printer leaves the factory.
In order to achieve dramatic improvements, it is necessary to provide more media-carried information to the printer than current detection marking methods can provide. Therefore, a new high capacity method is needed for marking and detecting information on donor media, receiver media or their associated structures such as spools or cassettes. Such additional information capacity would permit a printer to adjust its stored performance parameters to permit optimum print quality for each lot of dye donor or dye receiver, or for new media formulations.

SUMMARY OF THE INVENTION

An object of the present invention is to provide more information about a thermal printer media in a high information capacity indicia or detection mark applied to the media, or cassette holding the media, or like structure.
A further object of the present invention is to provide a method for a thermal printer for detecting a high information capacity indicia or detection mark, and decoding the same for subsequent operation of the printer.
Another object of this invention is to provide optimum print quality by adjusting for lot-to-lot variation in performance characteristics of the media.
Still another object of the present invention is to provide a method for a thermal printer for automatically adjusting printing parameters for new formulations of a media automatically.
A further object of the present invention is to store printing parameter modification information on the dye donor media, dye receiver media or support structures such as spool cores or cassettes.
Still a further object of the present invention is to store information on the media or support structures using data compression techniques, and to provide a thermal printer capable of decompressing such information.
Yet a further object of the present invention is to store information on the media or support structures using error detection and correction techniques, and to provide a thermal printer capable of implementing such error correction techniques.
According to the above objects, the present invention provides a method of storing information with a consumable thermal transfer printer medium, wherein medium information to be associated with a thermal transfer printer medium is compressed and stored in physical association with the thermal transfer printer medium. The information compression may be by adaptive means, by error correction code means, or other suitable means; with or without an error correction code and with or without encrypting. The information may be stored on the thermal transfer donor medium, on the thermal transfer receiver medium, on a label adhered to the medium, or on accompanying structure such as a spool or cassette.
The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiments presented below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 shows a dye donor cassette with bar coded information marked on a side;
FIGURE 2 shows a dye donor cassette with information marked on the end of a spool;
FIGURE 3 shows a cassette with information marked in the form of reflective strips;
FIGURE 4 shows a dye donor or dye receiver media with information marked on surface of the media;
FIGURE 5 shows a dye donor or dye receiver media with information formed as a portion of one of the layers which form the media;
FIGURE 6 shows a dye donor or dye receiver media with information marked in between layers which form the media;
FIGURE 7 shows a dye donor or dye receiver media with information marked in a machine readable code;
FIGURE 8 shows a dye donor or dye receiver media with information marked in a human readable code;
FIGURE 9 shows a dye donor or dye receiver media with information marked in an alphanumeric code;
FIGURE 10 shows a dye donor or dye receiver media with information marked in a customized shape;
FIGURE 11 shows a dye donor or dye receiver media with information marked in another customized shape;
FIGURE 12 shows dye donor or dye receiver media with information marked in a magnetically detectable strip;
FIGURES 13a, b and c show dye donor or dye receiver media with information marked in an electroconductively detectable strip;
FIGURE 14 shows a function block diagram of how data to be stored with media is compressed prior to storage;
FIGURE 15 shows a function block diagram of how data to be stored with media is first compressed and then encoded for error correction prior to storage;
FIGURE 16 shows a function block diagram of how data to be stored with media is encrypted prior to compression, followed by storage;
FIGURE 17 shows a function block diagram of how data to be stored with media is compressed prior to encryption, followed by storage;
FIGURE 18 shows a function block diagram of how data to be stored with media is encrypted, compressed and then encoded for error correction prior to storage;
FIGURE 19 shows how data to be stored with media is compressed, encrypted, and then encoded for error correction prior to storage;
FIGURE 20 shows a function block diagram of how data stored with media is detected and decompressed to output the original stored information;
FIGURE 21 shows a function block diagram of how data stored with media is detected, error corrected and decompressed to output the original stored information;
FIGURE 22 shows a function block diagram of how data stored with media is detected, decrypted and decompressed to output the original stored information;
FIGURE 23 shows a function block diagram of how data stored with media is detected, decompressed and decrypted to output the original stored information;
FIGURE 24 shows a function block diagram of how data stored with media is detected, error corrected, decrypted and decompressed to output the original stored information; and
FIGURE 25 shows a function block diagram of how data stored with media is detected, error corrected, decompressed and decrypted to output the original stored information.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGURE 1 shows a donor medium cassette 10 containing donor medium 11 with information marked on a side 12 in the form of a bar code 14 which would be detected by the thermal printer (not shown).
FIGURE 2 shows another donor medium cassette 16 containing donor medium 18 in which information is marked on the end of a spool 20 within dye donor cassette 16 in the form of long and short bars 22 which are detected by optical sensors 24 and 26 of a thermal printer (not shown).
FIGURE 3 shows a different method for conveying information in which reflective strips are located on a donor cassette 28 containing donor medium 30. A plurality of reflective strips 32-35 are attached to cassette 28 and can be detected optically, electrically or magnetically in such a way that their presence or absence indicates information.
Information can also be encoded directly on the donor media or receiver media. As shown in FIGURE 4, detection marks 36 can be located on the top of a dye or pigment layer 38 of the media, where layer 38 is on top of a support layer 40. Although not shown, detection marks 36 could also be formed on the support layer 40.
Alternatively, detection marks can be formed as an integral portion of one of the layers which make up the media such as in FIGURE 5 where the mark 36' is formed as part of the support layer 40'. Again not shown is the alternative where detection mark 36' is formed as part of a dye or pigment layer 38'.
Yet another method could have detection marks 36'' imbedded in the media between layers 38'' and 40'' as shown in FIGURE 6.
Information marked on media or structures such as cassettes may take many forms. Bar codes 14 and machine readable codes 22 have already been shown in FIGURES 1 and 2, respectively. A different machine readable code 42 marked on a donor medium 44 is shown in FIGURE 7. Additional forms include, but are not limited to, human readable codes 46 in FIGURE 8, alphanumeric codes 48 shown on a receiver medium 50 in FIGURE 9, or other codes such as optical character recognition codes (not shown). Other customized detection marks may also be used, such as geometric shapes 52 shown on a dye receiver 54 in FIGURE 10 and cut marks 56 shown on a continuous dye reciver medium 58 shown in FIGURE 11.
Media may be marked with information in patterns that are optically detectable by either transmission or reflection such as the bar code 14 in FIGURE 1, or on a magnetically detectable strip 60 shown on a continuous receiver medium 62 in FIGURE 12.
Electroconductively detectable marking methods 64 are shown in FIGURE 13A on a dye receiver 66, while mechanically detectable markings such as notches (not shown) are well known in photographic films. Finally, a bar code 68 or other mark could be applied to the receiver medium 70 as shown in FIGURE 13B. Any of the detection marks discussed herein could be applied with non-visible marking methods such as represented at 72 on a receiver medium 74 in FIGURE 13C.
FIGURE 14 shows a method for storing large quantities of information 100 in typical detection marks by compressing the information at 102 prior to forming the detection mark at 104. Information compression, also known as data compression or bandwidth compression, may be performed using any of a number of known methods such as but not limited to Lempel-Ziv codes, Huffman codes, run length codes, discrete cosine transform codes, differential pulse code modulation codes, vector quantization codes, or block truncation codes. Depending upon implementation, these codes could provide at least two to ten times the information storage capacity of uncompressed bar codes.
As shown in FIGURE 15, a greater amount of information 100 may be included in typical detection marks by compressing the information at 102 and then applying error correction codes at 106 to the compressed information prior to forming the detection mark at 108. This permits the use of higher compression codes while retaining data reliability through error correction methods. Some examples of error correction codes include but are not limited to BCH, Viterbi, Reed-Solomon and sequential codes. It is also possible, though less desirable, to apply error correction code methods to the uncompressed information.
FIGURE 16 shows another method for storing information with media, in which the data 100 is encrypted at 110 prior to being compressed at 102 and stored with the media at 112. The compression and encryption steps can also be reversed as shown in FIGURE 17.
An encryption step may also be added to the methods which include error correction. FIGURE 18 shows a sequence in which information 100 is encrypted at 110, followed by compression at 102 and error correction encoding at 114 prior to storing with the media at 116. FIGURE 19 shows the same steps with the compression at 102 and the encryption at 110 reversed.
FIGURE 20 shows a method for retrieving compressed information from a detection mark. The detection mark containing compressed information is first detected at 118 by the printer. A data decompression means 120 responsive to the detected information decompresses the information and outputs the information at 122 originally stored with the dye diffusion media. Information decompression, also known as data decompression or bandwidth decompression, uses the converse of the method used to compress the information originally. Thus the data decompression means would utilize a Lempel-Ziv decoder for data compressed with a Lempel-Ziv code. Similarly, the data compression means would utilize the corresponding decoder for information originally compressed using a Huffman code, run length code, et cetera.
The printer may, in some embodiments, have the ability to determine which code was used to compress the information and then choose the appropriate decompression method. Alternatively, the printer may utilize only a single decompression method.
As shown in FIGURE 21, information which is compressed and error corrected would be converted by first detecting the compressed, error corrected information at 118, correcting errors using an error correction decoder means 124 and decompressing the information at 120 to output the original information at 122. In a similar way to the compression and decompression means, the error correction encoding means and the error correction decoding means must utilize corresponding methods. For example, if the error correction encoder means utilized a Viterbi method, then the error correction decoder means must utilize the corresponding Viterbi decoder method. Similar correspondences apply for the other error correction methods.
FIGURE 22 shows another method for retrieving information stored with media. In this embodiment, the detection mark contains encrypted and compressed information which is detected at 126 by the printer. The detected information is then processed by a decryption means 128. The decrypted information is then decompressed at 120 to output the original information at 122. Note that the encryption means and the decryption means must correspond, similarly to the compression-decompression correspondence. The decompression and decryption steps can also be reversed as shown in FIGURE 23.
A decryption step may also be added to the methods which include error correction. FIGURE 24 shows a sequence in which information is detected at 126, following which it is error correction decoded at 130, decrypted at 128, and decompressed at 120 to output the original information at 122. FIGURE 25 shows the same steps with the decompression at 120 and the decryption at 128 reversed.
It is also possible to include some information with the detection mark which is not compressed, error corrected or decrypted. For example, the first two digits might represent which compression method was employed. The printer, upon reading the first two digits of the detection mark could then select the appropriate decompression, error correction decoder or decryption method with which to continue the transformation of the detected information into the original information. Thus, a printer could include more than one decompression method, error correction decoder method or decryption method and select which one to use based upon information within the detection mark.
By providing for the media to carry larger quantities of information, the present invention offers several advantages. It is possible to assure that correct media for the printer is in place (the printer knows how to print with the media which is loaded in the printer); the printer can adjust precisely for the media in the machine; and more information can be included in data detection marks. Further, more accurate operation of the printhead can be attained for a given manufacturing lot of media, resulting in higher quality prints. Look-up table correction factors can be incorporated in detection marks; new media formulations can be used in older printers; and complex information can be conveyed in the smallest possible form to printer. A plurality of marks can be used to convey large amounts of data to printer, perhaps even entire look-up tables can be recorded on the media. The present invention reduces need for expensive computer memory and/or storage means inside the printer, improves print quality by providing operating parameters for the specific media lot which is in the printer, and improves print quality lot-to-lot and from beginning to end of media lot.
The invention method is independent of the type of detection mark or storage means employed to store the information with the media, and a portion of the detection mark may not be compressed/error corrected/encrypted, allowing a combination of compressed and non-compressed information to be recorded in the detection mark; similarly with error correction and encryption.
The printer may include a plurality of decompression, error correction decoders or decryption methods, selecting the appropriate one based upon information included in the detection mark.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

Claims

A method of storing information with a consumable thermal transfer printer medium, the improvement comprising:
receiving medium information to be associated with a thermal transfer printer medium;
compressing said medium information; and
storing said compressed medium information in physical association with said thermal transfer printer medium.
A method of storing information with a thermal transfer printer medium as described in Claim 1 wherein said information storage step comprises storing information on the thermal transfer printer medium.
A method of storing information with a thermal transfer printer medium as described in Claim 1 wherein said information storage step comprises storing information on a structure accompanying said thermal transfer printer medium.
A method of storing information with a thermal transfer printer medium as described in Claim 3 wherein said accompanying structure is a spool.
A method of storing information with a thermal transfer printer medium as described in Claim 3 wherein said accompanying structure is a cassette.
A method of storing information with a thermal transfer printer medium as described in Claim 1 wherein said thermal transfer printer medium is a dye diffusion donor.
A method of storing information with a thermal transfer printer medium as described in Claim 1 wherein said thermal transfer printer medium is a dye diffusion receiver.
A method of retrieving information physically associated with a thermal transfer printer medium, the improvement comprising:
sensing medium information associated with a thermal transfer printer medium;
decompressing said medium information; and
adjusting print head printing parameters in response to said decompressed medium information.