TAPE SUPPLY AND TAPE CASSETTE

The present invention relates to a tape supply for a tape printing apparatus and also to a tape cassette with a tape supply for use in a tape printing apparatus. In particular, the present invention relates to a tape supply comprising a tape of direct thermal media for use with a tape printing apparatus and to a tape cassette housing said tape for use in a tape printing apparatus.

The Applicant has proposed in their earlier application, WO05/000586, a printer for printing on a direct thermal material which is capable of providing a coloured image.

A tape supply comprising a first part and a second part, said first part comprising an exposed colour layer, said colour layer being activatable to provide an image, one of said first and second parts comprising a protective layer, wherein said first and second parts are arranged in used to be applied one to the other so said colour layer is protected by said protective layer

For a better understanding of the present invention and as to how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

Figure 1 shows a schematic diagram of an embodiment of a tape printing apparatus embodying the present invention;

Figure 2 shows schematically control circuitry for controlling a tape printing apparatus embodying the present invention;

Figure 3 shows a schematic diagram of an embodiment of a cassette according to the present invention, with parts of the tape printing apparatus;

Figure 4 shows a schematic diagram of a colour coating used in embodiments of the present invention;

Figure 5 shows a first embodiment of a tape supply embodying the present invention; and

Figure 6 shows a second embodiment of a tape supply embodying the present invention.

Reference is first made to Figure 5 which shows a tape supply embodying the present invention. The tape supply comprises a first part 2 and a second part 3. The first and second parts are initially separate.

The first part has a first layer 5 which comprises a clear material which acts as a protective layer. This first layer may be of PET (Polyethylene Terephthalate), polypropylene or other polyolefin, or similar material. The protective layer may be transparent or coloured.

Optionally the protective layer may be provided with UV blockers. These prevent UV light from passing through the top layer or at least block some UV light from passing through this layer.

This protective layer is to provide water fastness and/or improved resistance to wear.

A clear adhesive layer 6 may be provided on the underside of the first layer 5. This adhesive layer may optionally have UV blockers. It should be appreciated that both the first layer 5 and the adhesive layer 6 may have UV blockers. Alternatively only one of these layers may have UV blockers. In yet a further embodiment, neither of the layers may be provided with UV blockers. In the adhesive may be transparent or be coloured.

The second part 3 comprises a colour layer 7. This colour layer will be described in more detail hereinafter. The colour layer is provided on a carrier 8. The carrier can be of any

suitable material such as PET, or polypropylene or other polyolefin. The opposite side of the carrier 8 has a layer of adhesive and/or an ink layer 9. In some embodiments, the ink may be omitted. The adhesive and/or ink layer thus can be transparent and clear, coloured and clear, opaque or coloured and opaque.

The opposite side of the adhesive/ink layer 9 has a backing layer 10. This can be removed from the adhesive layer 9 to allow the material to be adhered to a surface or the like. If the adhesive layer is omitted, the backing layer may also be omitted.

In use, the second part 3 of the tape supply will pass through the print zone of a tape printing apparatus (which will be described in more detail later). As indicated by arrows 11, an image is printed by activating the colour layer 7. The first part 2 of the tape assembly will then be applied to the second part 3 of the tape assembly or vice versa. In particular the clear adhesive layer 6 of the first part 2 is brought into contact with the colour layer of the second part 3 to provide a single tape. As mentioned previously, the backing layer 10 can be removed to allow a printed label to be affixed to any suitable surface.

In use, the image is therefore viewed through the protective layer 5, which protects the image from being worn away or degraded. It may also protect the image from degradation caused by UV light if the protective layer 5 and/or the adhesive layer 6 of the first part contain UV blockers.

Reference is now made to Figure 6 which shows a modification to the arrangement of Figure 5. The tape supply of Figure 6 comprises a first part 12 and a second part 13.

The first part comprises a protective layer 12, which has a similar function and characteristics to the protective layer 5 described in relation to Figure 5.

A colour layer 14 is provided on the underside of the protect layer 12. Again the colour layer provides a similar function and has similar characteristics to the colour layer 7 of the first embodiment of Figure 5. However the colour layer 14 is provided at a different location that is provided on the underside of the protective layer 14, as compared to the first embodiment.

The second part 13 of the tape supply comprises a carrier layer 16, which provides a similar function and has similar characteristics to the carrier layer 8 of the first embodiment.

Provided on the underside of the carrier layer 16 is an ink and/or adhesive layer 17. This layer has a similar function and characteristics as the corresponding layer 9 of the first embodiment. On the opposite side of the adhesive/ink layer 17 to the carrier is a backing layer 18 which again is similar to the corresponding layer 10 described in relation to the first embodiment.

In the embodiment shown in Figure 6, the first part 12 of the tape supply is arranged so that when it is passed through a print zone of a tape printing apparatus, an image is provided by activating the colour layer. In some embodiments of the invention, this will be achieved by the print head of the tape printing apparatus being in contact with the colour layer, whilst in others this may be achieved by the print head of the tape printing apparatus being in contact with the protective layer. The printing in preferred embodiments of the invention is indicated by arrows 19.

When an image has been printed, the second part 13 of the tape supply is applied to the first part 12 or vice versa. In particular, the carrier layer 16 is brought into contact with the coloured layer 15. In the embodiment shown in Figure 6, the carrier layer may have adhesive properties. In one modification, an adhesive layer is provided on the side of the carrier layer opposite to the ink/adhesive layer 17 to cause the first and second parts to be adhered together.

The printed image would be viewed through the protective layer 14 of the first part 12. In order that the image can be correctly viewed, mirror printing would be used. This means the characters etc are formed in such a way that when viewed through the protective layer, they appear normal.

In one modification to either of the two described embodiments, it is possible to omit the carrier layer.

The protective layer can have any suitable thickness, for example between 10 and 30 micrometers. More preferably the thickness will be in the range of between 15 and 25 micrometers. In one preferred embodiment, the thickness used may be 20 micrometers.

In one modification to the arrangement shown in Figure 5, there may be two modes of using the tape supply. In a first mode, the first part is applied to the second part (or vice versa). In a second mode, an image is printed on the second part and the second part is used to provide a label without the application of the first part. Thus the first mode would be used to produce more durable labels, for example for outside use, whilst the second mode could be used to produce less durable labels, for example for inside use.

In preferred embodiments of the invention, the print head is arranged to contact the colour layer. Because the colour layer is exposed to the print head during printing and then subsequently covered because of the application of the first and second parts, one to the other, there is no need to provide any additional protection characteristics in the colour layer. Thus the colour layer need only provide the function of providing the image. This means that the colour layer can be optimised in terms of performance of the colour layer without having to balance performance against other considerations. It has been found that in implementations which have the colour layer uppermost in the finished layer, it is necessary to provide protective properties or a protective layer. This means that the colour gamut and/or speed of

printing are reduced. Embodiments of the present invention are able to improve on such implementations.

In some embodiments of the invention, the carrier film may be opaque and coloured. Alternatively the carrier film may be clear and coloured or clear and transparent.

Referring now to Figure 4, there is seen a schematic example of the colour layer used in embodiments of the invention, such as discussed in relation to Figures 5 and 6. Thermal delays are used to define the printing regions for the colours to be formed. The three colour imaging member 73 includes cyan, magenta and yellow image-forming layers, 18, 20, 22, respectively, and spacer inter layers 24, 26.

Where the image member is heated by a thermal print head from above, the cyan image- forming layer 18 will be heated almost immediately by the thermal print head after the heat is applied, but there will be a significant delay before the magenta image-forming layer 20 and the yellow image-forming layer 22 are heated according to the thermal conductivity and thickness of the spacer layers 24, 26. To provide multicoloured printing it is preferable that each image-forming layer is arranged to be activated at a different temperature. This result can be achieved, for example, by arranging the image-forming layers to have different melting temperatures or by incorporating in them different thermal solvents, which will melt at different temperatures and liquefy the image-forming materials. For example, if the activation temperature for the cyan layer is Tl, the activation temperature for the magenta layer is T2 and the activation temperature for the yellow image-forming layer is T3, then the activation temperatures may be selected such that Tl > T2 > T3. Accordingly, application of a temperature between T2 and T3 for a relatively long time period will produce a yellow colour without any cyan or magenta colour. A relatively short, high temperature heat pulse above Tl will produce a cyan colour without any magenta or yellow colour. Application of a temperature between Tl and T2 for a suitable length of time will produce a magenta colour.

Accordingly, by varying the temperature and time of heating, individual colours or mixtures thereof may be produced so as to generate a multicolour image.

Three coloured layers are shown. In alternative embodiments of the invention, there may be only two or one coloured layer.

Embodiments of the invention have shown coloured layers with magenta, cyan and yellow. It should be appreciated that in alternative embodiments of the invention there can be different colours in the layers. Depending on the technology used, it is possible that the dyes or the like can be incorporated in a single layer or two or more colours can be produced from the same layer.

The arrangement of Figure 4 is schematic and in practice there may be many more than three layers. The spacer layers may be optional. In alternative embodiments of the invention, the coloured layer may not be made up of layers but instead have different agents which when activated at the appropriate temperature, provide a coloured image.

Figure 1 shows a schematic diagram of an embodiment of a tape printing apparatus 28 according to the present invention. The tape printing apparatus comprises a keyboard 30 and a cassette receiving bay 32. The keyboard has a plurality of data entry keys 34 such as numbered, lettered and punctuation keys for inputting data to be printed as a label and function keys for editing the input data. The keyboard may also have a print key 36 which is operated when it is desired that a label be printed. Additionally an on/off key 38 is also provided for switching the tape printing apparatus on and off.

The tape printing apparatus has a liquid crystal display (LCD) 40 which displays the data as it is entered. The display allows the user to view all or part of the label to be printed which facilitates the editing of the label prior to its printing. Additionally, the display is driven by a display driver (not shown).

Basic circuitry for controlling the tape printing device 1 is shown in Figure 2. There is a microprocessor chip 200 having a read only memory (ROM) 202, a microprocessor 201 and random access memory capacity indicated diagrammatically by RAM 204. The microprocessor chip 200 is connected to receive label data input to it from a data input device such as a keyboard 206. The microprocessor chip 200 outputs data to drive a display 208 via a display driver chip 209 to display a label to be printed (or a part thereof) and/or a message for the user. The display driver alternatively may form part of the microprocessor chip. Additionally, the microprocessor chip 200 also outputs data to drive the print head 216 so that the label data is printed onto the image receiving tape to form a label. Finally, the microprocessor chip 200 also controls the motor 207 for driving the platen. The microprocessor chip 100 may also control the cutting mechanism to allow a length of tape to be cut off. In alternative embodiments at least part of the cutting mechanism may be manually operated.

Reference is made to Figure 3 which shows in plan view a tape printing device 300 embodying the present invention which has a cassette 306 arranged therein. This cassette can contain a first supply 301 of the part of the tape supply having the colour layer and a second supply 302 of the part to be applied thereto. The first and second supplies can be in accordance with the embodiments shown in Figures 5 and 6. In the case of the first embodiment of Figure 5, the first supply 301 is the second part 3 whilst the second supply is the first part 2. hi the case of the second embodiment of Figure 6, the first supply is the first part 12 whilst the second supply is the second part 13.

The cassette 306 is located in a cassette bay 316. The cassette bay 316 also accommodates at least one thermal print head 304 and a platen 308 which cooperate to define a print zone 302. The print head 304 is able to pivot about a pivot point 324 so that it can be brought into contact with the platen 308 for printing and moved away from the platen 308 to enable the

cassette 306 to be removed and replaced. In the operative position, the platen 308 is rotated to cause the tape having the colour layer 310 to be driven past the print head 304.

The platen 308 is driven by a DC motor (see Figure 2) so that it rotates to drive the image receiving tape 310 through the print zone 302 of the tape printing device 301 during printing. In this way, an image is printed on the tape and fed out from the print zone 302.

The image is printed by the print head 304 on the tape 310 on a column by column basis with the columns being adjacent one another in the direction of movement of the tape 310. Pixels are selectively activated in each column to construct an image in a manner well known in the art. The DC motor is provided with a shaft encoder for monitoring the speed of rotation of the motor. The control of the speed of the motor is achieved by the microprocessor chip 100 (see Figure 2) to generate data strobe signals each of which causes a column of pixel data to be printed by the print head 304.

The tape printing device may include at cutting location 320 a cutting mechanism 328 which carries a blade 318. The blade 318 cuts the image receiving tape 310 then enters a slot 330 located in the cassette 306.

The tape printing apparatus comprises a pair of rollers 326 and328 which cooperate together. These rollers 326 and 328 are arranged between the print zone 302 and the cutting location 320. The rollers are arranged to draw the material 340 from the second supply 302 and to cause the material to be applied to the printed image as the two tape parts pass between the rollers 326 and 328. The coloured image will be covered by the second supply (or vice versa).

It is understood that other embodiments of the tape printer may be envisaged. For example, the tape printing apparatus embodying the present invention may be a PC printer rather than a stand-alone printer. In such a tape printing apparatus, a keyboard and display means are not essential as the data may be input and displayed on the PC. The PC then acts as an input

device for the printer. Alternatively, other apparatus may be used to input data to the printer for printing. For example, in an embodiment of the invention a digital camera may be used to input data to the tape printing device for printing. Images may alternatively be input using a smart card, chip card, memory card, memory stick or the like.

It is understood that other embodiments of the tape printer may be envisaged in which the receiving bay receives two rolls of material, as shown in Figures 5 and 6, without the need of a cassette. This may reduce the cost of replacing the tape supply. However, the use of a cassette to house the tape ensures that the tape supply remains in good condition both during storage and when introduced into a printer for use. In one embodiment, as described above the two parts are included in the same cassette. However in alternative embodiments of the invention, the two parts may be provided in respective separate cassettes. It is also possible that one of the parts of the tape supply be provided in a cassette, with the other of the parts of the tape supply provided in roll format.

It is also preferably that if the tape supply is provided in one or more cassettes that the at least the cassette containing the colour layer be light tight as excessive exposure of light to some tapes may have an adverse effect. In some embodiments of the invention, the tape is wound on the tape supply roll so that the thermally sensitive surface, that is the coloured layer, is inwards.

During printing, the print control means in the form of a processor controls the print head whereby dyes of different colours are selectively reacted to produce a multicoloured image. The criteria for selective reactivity depend on the thicknesses of the tape layers, the thermal conductivity of the layers, the temperature coefficients of reaction for the dye precursors, the heating temperature and the heating time. It is envisaged that a number of image-forming techniques may be exploited including thermal diffusion with buried layers, chemical diffusion or dissolution in conjunction with timing layers, melting transitions and chemical

thresholds. Selective light activated reactions may also be utilized in order to achieve multicolour colour printing.

During printing, the processor controls the print head and in particular, the temperature of each print head pixel is controlled according to data input from the keyboard, PC or other input device. The temperature or energy of each pixel is continuously variable whereby an image of continuously variable optical density and/or colour may be produced. The processor also controls the print head strobe time, that is the width of a pulse and/or the number of pulses. The control of the heating temperature and the heating time allows a multi-coloured image to be produced on the direct thermal image tape.

The tape printing apparatus and the tape are adapted to produce a multicoloured image on the tape by direct thermal transfer in a single pass of the tape, that is no reversing of the tape is required. The processor is adapted to control the printing elements according to data input to the tape printing apparatus by a user. For example, a user can select different colour schemes for a label via the keyboard. The processor controls the temperature and the time period each printing element is heated and the temperature of each element is continuously variable. In some embodiments, the energy can be varied in a stepwise fashion rather than continuously.

A memory is provided for holding temperature, heating period and colour data which is accessible by the processor to select a temperature and heating period for each printing element according to data input to the tape printing apparatus. The memory may hold temperature, heating period and colour data for different types of direct thermal tape as well as for thermal transfer tapes (which use an ink ribbon). In one embodiment the tape printing apparatus has a detection means for detecting the type of direct thermal tape inserted in the tape printing apparatus (for example, it could be a two colour tape or a full multicolour tape) or if it is a thermal transfer tape and the detecting means sends a signal to the control means whereby the data corresponding to the detected tape type is selected. In this way, a tape printing apparatus can be used for several different embodiments of direct thermal image tape.

The detection means may be physical e.g. the tape cassette may activate a switch according to the shape of the body of the cassette when introduced into the tape printing apparatus. Alternatively, it may be electrical, optical, RF, magnetic, in the form of markings or may be selected by a user manually.

The above-described embodiments enable a method of printing a label in which a multicoloured image is produced on the tape by direct thermal transfer in a single pass of the tape past the print head. . As a result, higher quality colour images are achieved.

It should be appreciated that depending on the structure of the material, the number of print heads used can be one, two or three. It should also be appreciated that embodiments of the present invention can be used with direct thermal materials which provide more limited colour images. For example, embodiments of the present invention can be used with dichromic or tri-chromic materials. In those cases, the number of print heads and print head control may be simplified. In some embodiments of the present invention, the material can be monochromic where the colour is any colour other than black.

It should be appreciated that tape printing apparatus embodying the present invention can be used to provide colour images but can also be used with thermal material to provide a single printing colour with no variability in the background colour. In other words, the tape material will have a predetermined colour and an image can be printed in a single colour usually black.

Tape printing apparatus embodying the present invention can also be arranged to do thermal transfer printing, that is using an ink ribbon.

Preferred embodiments of the present invention are arranged so that information is automatically provided to or detected by the tape printing apparatus about the capabilities of the material. In other words whether the material is full colour, a thermal transfer material, a direct thermal material only providing one colour or a colour direct thermal material

providing two or more colour options and if so what those colour options are. This information can be provided in a number of different ways. For example, the tape supply and/or cassette may have an element which provides the necessary information. In alternative embodiments of the present invention, the user may be able to set this from the keyboard. In other words, the user will provide the tape printing apparatus with information as to the type of tape material so that the tape printer can be controlled accordingly.

It should be appreciated that embodiments of the invention are applicable to continuous tape and also, where appropriate die cut labels arranged on a continuous backing layer.