JP2006527097A - System for label printing on substrate and method for label printing on optical disc - Google Patents

Abstract

A system (10) and method for label printing on optical disk (14) recording media and other substrates using leuco dyes in electromagnetic radiation sensitive compositions is described. Isobenzofuranone-containing leuco dyes are prepared in various compositions comprising activators, radiation absorbers, and optional non-leuco colorants, and / or various carriers. The leuco dye composition can be applied and prepared so as to achieve a desired visual effect when developing the leuco dye.

Description

The present invention generally relates to the application of leuco dyes. More particularly, the present invention relates to the use of black leuco dyes for substrate labeling.
(Priority information)
This application is a continuation-in-part of US patent application Ser. No. 10 / 351,188, filed Jan. 24, 2003, which is incorporated herein by reference.

  Optical discs represent a significant share in the market for software data storage and data storage of photographic, video, and / or audio data. Typically, an optical disc is embedded with a data pattern that can be read from one or both sides of the disc, and a graphic display is printed on the other side of the disc. The data readable surface of the disk, i.e., the data surface, includes helical trajectories of various spaced recesses called pits separated by unsunk surfaces called lands. A low power laser is focused on the spiral trajectory. The difference in height between the pits and lands causes a phase shift of the reflected beam that can be measured and translated into usable data. Currently, various optical disk formats such as CD, CD-ROM, CD-R, CD-RW, DVD, DVD-R and DVD-RW are used. Other optical disc formats can also be utilized.

  A print pattern or graphic display information can be printed on the non-data side of the disc to identify the contents of the optical disc. Both the pattern or graphic display can be decorative and provide relevant information regarding the data content of the disc. In the past, commercial label printing has always been done by screen printing. While this method can provide a wide range of label content, it is cost effective for production of less than about 400 discs due to the fixed costs associated with creating a stencil or combination of stencils and printing the desired pattern or graphic display. Tend to be low.

  In recent years, the use of optical disks for data storage by consumers has increased remarkably, and there has been an increasing need to provide a dedicated label that reflects the contents of optical disks. Most label displays currently available to consumers are limited to either handwritten descriptions as well as pre-printed labels that can be attached to the disk but can adversely affect disk performance during high speed rotation.

  It has been recognized that it would be useful to develop alternative systems and methods for label printing on substrates such as optical disks.

  In one embodiment, an optical disc according to an embodiment of the present invention may include an optical disc substrate on which an electromagnetic radiation sensitive composition is coated. The electromagnetic radiation sensitive composition can include a leuco dye that can produce a black image upon color development, in which case the leuco dye is an isobenzofuranone-containing dye. The electromagnetic radiation sensitive composition can also include an activator configured to react with the leuco dye. The electromagnetic radiation sensitive composition can also include an electromagnetic radiation absorber that is mixed with or in thermal contact with the leuco dye, under the influence of electromagnetic radiation sufficient to promote the reaction. It becomes thermally active.

  The present invention includes a system for label printing on a substrate, the system comprising an image data source, a substrate coated thereon with an electromagnetic radiation sensitive composition, and an electromagnetic radiation sensitive composition. And a radiation source for developing the color. The electromagnetic radiation sensitive composition can include a leuco dye, such as an isobenzofuranone-containing dye, that can produce a black image when developed. Further, the composition can include an activator configured to react with the leuco dye and is thermally active under the influence of electromagnetic radiation sufficient to promote the reaction. It can include an electromagnetic radiation absorber mixed with or in thermal contact with the leuco dye. The electromagnetic radiation source is operatively connected to the image data source and can be configured to induce electromagnetic radiation into the electromagnetic radiation sensitive composition.

  In other embodiments, a system for label printing an optical disc can include a series of processing steps. One step includes applying an electromagnetic radiation sensitive composition to the surface of the optical disc, wherein the composition comprises a black leuco dye, an activator, and an electromagnetic radiation absorber, The leuco dye is an isobenzofuranone-containing dye. The second step can include transferring image data from the data source to an electromagnetic radiation source configured to generate electromagnetic radiation. The third step includes at least part of the electromagnetic radiation sensitive composition by exposure to electromagnetic radiation at a predetermined frequency, intensity, time, and spot size to produce a visible image on the optical disc. Can be included.

  Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the features of the invention.

  Reference will now be made to the exemplary embodiments described in the drawings, and specific language will be used to describe the same. Nevertheless, it will be understood that it is not intended to limit the scope of the invention. Those skilled in the art and those skilled in the art will appreciate changes and further improvements in the features of the invention described herein, as well as further principles of the invention as described herein. Application examples are also considered to be within the scope of the present invention. Further, in disclosing and describing detailed embodiments of the present invention, it is to be understood that the present invention is not limited to the specific processes and materials disclosed herein. This is because they can be changed to some extent. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The scope of the present invention is limited only by the appended claims and their equivalents.

  In describing and claiming the present invention, the following terminology will be used.

  Unless otherwise explicitly indicated, the singular forms “a”, “an”, and “the” include plural meanings. Thus, for example, reference to “a leuco dye” includes reference to one or more of the materials.

  As used herein, “optical disk” is intended to include audio, video, multimedia, and / or software disks that are machine-readable on a CD and / or DVD drive or the like. Examples of optical disc formats include writable discs such as DVD, DVD-R, DVD-RW, DVD + R, DVD + RW, CD, CD-ROM, CD-R, CD-RW, recordable disc, and rewritable disc A disk is included. Other similar formats can also be included, such as similar formats and formats developed in the future.

  As used herein, “graphical display” can include any visually recognizable character or image on an optical disc. Typically, the graphic display is not always, but prominently on one side of the optical disc.

  As used herein, “data” as used in connection with the present disclosure typically includes non-graphical information contained on an optical disc that is digitally or otherwise embedded therein. included. The data can include audio information, video information, photo information, software information, and the like.

  As used herein, “isobenzofuranone-containing” means any compound that is suitable for use in the present invention and includes the following subgroups.

  As used herein, “leuco dye” means a dye in a form that is substantially colorless or white before color development and that turns black upon exposure to heat. The discoloration phenomenon is typically due to chemical changes, such as oxidation, that occur upon exposure to heat.

  The term “activator” means a composition that interacts or reacts with a leuco dye when heat is transferred.

  As used herein, “develop” or “development” refers to the interaction of a leuco dye with other reactants such as activators or the like to produce a visible compound of the desired color or It means reaction. The interaction is most often initiated by heat, but may actually be physical.

  As used herein, “absorbent” generally refers to an electromagnetic radiation sensitive agent that can generate heat when exposed to electromagnetic radiation of a predetermined frequency. The predetermined frequency can vary from one absorbent composition to another. When mixed or in thermal contact with the leuco dye and / or activator, the absorbent will generate sufficient heat to at least partially develop the leuco dye according to embodiments of the present invention. Can be present in sufficient amounts. Typically, the development of the leuco dye can occur due to the interaction between the leuco dye and the activating composition.

  The term “thermal contact” means the spatial relationship between the absorbent and the leuco dye-activator composition. For example, when the absorbent is heated by interaction with electromagnetic radiation, the heat generated by the absorbent should be sufficient to cause the leuco dye to darken through reaction with the activator. Thermal contact can include intimate proximity between the absorbent and the leuco dye, which allows heat transfer from the absorbent to the leuco dye and / or activator. Thermal contact can also include actual contact between the absorbent and the leuco dye, such as in an immediately adjacent layer, or in a mixture containing both components.

  “Carrier” or “carrier component” refers to a composition or additive that can be used with leuco dyes, absorbents, and / or activators to form one or more layers on the surface of a substrate. It is defined as including. Surfactants, polymers, UV curable materials, etc. can be used as carriers. The combination of leuco dye and absorbent can be present in the same carrier, or can be in separate carriers that are sequentially fed to the substrate. In some embodiments, additives such as colorants can be added to the carrier.

  As used herein, “optical density” refers to the logarithm of the reciprocal of reflectance, where reflectance is the ratio of reflected intensity to incident intensity.

  In this specification, concentrations, amounts, and other numerical data may be presented in a range format. Such range formats are merely used for convenience and brevity and do not only include the numerical values specified as the limits of the range, but each numerical value and sub-range is within that range as specified. It should be understood that it should be construed flexibly as including all individual numerical values or sub-ranges that are encompassed by. For example, a size range of about 1 μm to about 200 μm not only includes the stated concentration limits of 1 μm to about 200 μm, but also individual concentrations such as 2 μm, 3 μm, 4 μm, and 10 μm-50 μm, 20 μm-100 μm, etc. Should be construed as including sub-ranges such as

  1 illustrates a system for label printing on a substrate having a black leuco dye thereon, according to the present invention, generally designated 10 as illustrated in FIG. In this embodiment, the system can simultaneously write to the image surface 12 of the optical disc 14 and collect and / or write data to the data surface 16 of the optical disc. The optical disk substrate 18 is shown in a first orientation with the image surface 12 facing upward. In order to rotate and support the optical disc 14, a motor 20 and a support element 22 are present.

  In accordance with the present invention, the image is stored digitally in the image data source 24. This image information can be created using a number of commercially available image software programs. The image can then be rasterized or spiraled and sent via a signal processor 26 to an electromagnetic radiation source for label printing. This process generally involves digitizing the image data to correspond to a spiral path that matches the path followed by the electromagnetic radiation source with respect to the image plane of the rotating optical disc. In one embodiment, the label printing electromagnetic radiation source is a radiation device 28a and an optical label detection device 30a facing the image surface 12 of the rotating optical disk 14 having the leuco dye composition 32 thereon. In addition, an optional second radiation device 28b and second detection device 30b face the data surface 16 and are configured for simultaneous read and / or write operations. Data can be generated, used, and / or stored in the data source 34. In one embodiment, the data can be written by sending it to the second radiating device 28b via the signal processor 26. Each set of emitters and detectors is disposed on a first thread 36a and a second thread 36b, respectively. Further, each of the first thread 36a and the second thread 36b moves along the first track 38a and the second track 38b. In this embodiment, a single solenoid 40 is shown that functions to move both the first thread 36a and the second thread 36b together in unison and collect information. However, this is not required.

  In an alternative embodiment, each thread can be configured to be unaffected by the other. In such embodiments, two solenoids or other mechanical or electrical structures can be used to fulfill independent functions. In addition, other embodiments are possible, such as using a single track and solenoid combination, such as those available for typical CD-R / CD-RW drives. The same emitter and diode combination can be used to turn the disc over after reading and writing data and develop a black image using the leuco dye of the present invention.

  The present invention generally relates to label printing substrates with specific black leuco dyes. 2A, 2B and 2C illustrate an optical disc comprising a substrate having various coatings, generally designated 14; The substrate 18 is generally used as a structural support and has a data surface 16 and a label surface 12. The substrate 18 can be made from any suitable material, such as polycarbonate or other polymeric material that faces the optical disc. Data layer 42 is typically formed by sputtering or other known processes and contains any known material that can generate, maintain, and / or simulate pits and lands corresponding to unique data. be able to. Thus, although a single data layer is shown, it is understood that multiple layers may also be used, which are suitable for writable and / or rewritable formats. Materials for use in creating permanent (ROM) format, writable format, or rewritable format are well known to those skilled in the art. These materials include, but are not limited to, aluminum, cyanine, phthalocyanine, metal-containing azo dyes, and photosensitive compounds in the polymer binder of the dye layer. For example, rewritable optical discs typically include quaternary phase change alloys that exhibit various reflective properties in the amorphous and crystalline states. The data layer can also include colorants that do not affect the data storage performance of the data layer. The composition is readable or writable with respect to the data surface 16 of the optical disc 14.

  The black leuco dye and activator of the present invention can be prepared by various methods, and can be applied to an optical disc capable of reading or writing data. For example, an electromagnetic radiation sensitive composition 44 as shown in FIG. 2A can be prepared containing a black leuco dye, an activator, an electromagnetic radiation absorber, and a carrier. Carriers include surfactants and / or Almacryl® T-500, polyacrylates from monomers and oligomers, polyvinyl alcohol, cellulose esters, polyvinylpyrrolidine, polyethylene, polyphenols or polyphenol-based esters, polyurethanes, etc. A polymeric material can be mentioned. The electromagnetic radiation sensitive composition of the illustrated embodiment is used not only to provide the function of a leuco dye and activator, but also to protect the top surface of the disk, so that the lubricant, surfactant, and Various additional ingredients, such as substances that impart moisture resistance, can be added to provide mechanical protection to the electromagnetic radiation sensitive composition.

  In an alternative embodiment, the electromagnetic radiation absorber can be applied in a layer separate from the leuco dye layer, where the separate layer is disposed on the substrate before or after the leuco dye. FIG. 2B shows a leuco dye layer 46 containing a black leuco dye and an activator in a suitable carrier. The composition is formed on the data layer 42 and can cover the entire area or just a portion of the optical disk 14. In the embodiment described in FIG. 2B, the absorbent layer 48 can be formed as a separate layer (using a carrier containing the absorbent), which covers at least a portion of the optical disc. Accordingly, the leuco dye layer 46 and the absorbent layer 48 together constitute an electromagnetic radiation sensitive composition. In one embodiment, an absorbent layer 48 can be formed on the portion of the optical disk 14 that is at least about the same as the leuco dye layer 46 so that the leuco dye composition 46 develops as desired on the surface of the optical disk. . This results in an optical disc having an absorbent layer 48 that is in thermal contact with the leuco dye 46. A layer group can be said to be in thermal contact if the two layers are not actually in contact but are in close enough proximity that sufficient thermal activation of the leuco dye occurs. An optional inert protective layer 50 can be formed to provide mechanical protection to the leuco dye layer 46 and the absorbent layer 48. The protective layer can be substantially transparent or translucent to allow sufficient electromagnetic radiation to pass through and allow the electromagnetic radiation sensitive composition to develop.

  In yet another embodiment of the invention, FIG. 2C shows an optical disc 14 having a substrate 18, a data layer 42, and a first protective layer 52. The electromagnetic radiation sensitive composition layer 54 may comprise the absorber and leuco dye and activator as separate layers, as described above, so as to include a leuco dye, an activator, an electromagnetic radiation absorber, and a carrier. Can be made by mixing together. The first protective coating layer 52 protects the data layer 42 as is common in writable and rewritable optical discs currently on the market. The second protective coating layer 56 protects the electromagnetic radiation sensitive composition layer (s) 54. The protective coating described above may be a coating including lacquer, UV coating, or polymeric film.

  For each embodiment listed in the drawings, and for equivalent embodiments, a black leuco dye suitable for use in the present invention is an isobenzofuranone-containing dye. In general, leuco dyes are substantially colorless and are lactone ring-closed forms. Such dyes include 3-di-n-pentylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3- (n It can be a leucofluorane dye such as -ethyl-n-isopentylamino) -6-methyl-7-anilinofluorane and 3-pyrrolidino-6-methyl-7-anilinofluorane. The corresponding chemical structures are shown below.

  Leuco dyes containing halides such as halide isobenzofuranone leuco dyes can also be used in the present invention. An example of a halide-containing isobenzofuranone leuco dye is tetrahalide composition 1 (3H) -isobenzofuranone, 4,5,6,7-tetrachloro-3,3-bis [2- [4- (dimethylamino ) Phenyl] -2- (4-methoxyphenyl) ethenyl] and has the following structure:

  When heat-induced oxidation, protonation, ring opening, or the like occurs in the presence of an activator, the isobenzofuranone-containing leuco dye listed above can form a black dye having a high optical density. Although a wide range of compositions are suitable for use in the present invention, the electromagnetic radiation sensitive composition can contain less than about 60% leuco dye and activator by weight, preferably at about 40 wt%. is there. These ranges are merely exemplary, and other weight ranges can be used depending on the desired image characteristics and other considerations. An activator to leuco dye weight ratio of about 1: 4 to about 4: 1 typically provides suitable results, and a ratio of about 2: 1 can be used.

  As mentioned above, the interaction between the leuco dye and the activator can cause a chemical change in the leuco dye, thereby changing the color of the leuco dye from substantially white or colorless to substantially black. it can. In general, chemical changes in leuco dyes are caused by applying a predetermined amount of heat. Activators suitable for use in the present invention can be selected by those skilled in the art. Some non-limiting examples of suitable activators include phenols, carboxylic acids, Lewis acids, oxalate complexes, succinic acid, zinc stearate, and combinations thereof.

  When a predetermined amount of heat is applied by the electromagnetic radiation absorber, the system can be optimized by matching the electromagnetic radiation frequency and intensity to the absorbent used. The absorbent may be present in the electromagnetically sensitive leuco dye composition, typically in an amount of about 0.001 wt% to about 10 wt%, although other weight ranges depending on the specific absorbent activity. May be required. Examples of frequencies that can be selected include infrared, visible, ultraviolet, or combinations thereof.

  The absorbent can be configured to have a heat transfer relationship with an isobenzofuranone-containing leuco dye. For example, the absorbent can be disposed as part of the mixture in the same layer as the isobenzofuranone-containing leuco dye, or can be disposed in a separate layer. That is, the absorbent can be mixed with the leuco dye composition or brought into thermal contact. In one embodiment of the present invention, the absorbent can be applied as another adjacent layer to the substrate before or after the leuco dye composition is applied as a layer. In one embodiment, consideration is also given to selecting an activator such that light absorbed in the visible range does not adversely affect the graphical display or appearance of the undeveloped leuco dye. Inorganic compounds can also be used, but the absorber is typically but not limited to organic compounds such as infrared absorbers, ultraviolet absorbers, visible light absorbers, and the like. More particularly, examples of absorbents suitable for use in the present invention include, but are not limited to, metal complex IR dyes, indocyanine green, heterocyclic compounds, and combinations thereof. K using a metal complex IR dye such as a dithiolane metal complex having the following general formula:

  In the formula, M can be a transition metal, and R1 to R4 can be lower alkyl or aryl groups.

  Indocyanine metal complexes such as the following compounds may also be suitable.

  Where M can be Ni, Cu, or other transition metal, and each R can independently be H, lower alkyl, and / or aryl. IR780 and IR783 (available from Aldrich Chemical Co.) and dithiophenylidene compounds (Syntec 9/1 and Syntec 9/3), respectively, shown in the figure below, can also be used in the present invention.

  Other suitable absorbents can also be used in the present invention and are known to those skilled in the art and are described in “Infrared Aborving Dies”, Matsuoka, Masaru, ed. , Plenum Press, New York, 1990 (ISBN 0-306-43478-4) and “Near-Infrared Dies for High Technology Applications”, Daehne, Resch-Genger, Wolfbeis0, 23 )), Both of which are incorporated herein by reference. Although the specific activators and absorbents discussed herein are separate compounds, the above-mentioned activities also provide for leuco dyes that impart activation and / or radiation absorption within the leuco dye molecule. It can also be provided by a component group.

  In another aspect of the invention, the black isobenzofuranone leuco dye can be developed under conditions that are exposed to certain types of electromagnetic radiation, including electromagnetic radiation generated using a laser. Lasers that produce radiation at visible, infrared, and ultraviolet frequencies can be utilized. For example, lasers having any frequency from about 650 nm to about 815 nm are readily available on the market.

  The conditions for developing the leuco dye of the present invention can be changed. For example, electromagnetic radiation frequency, heat flux, and exposure time can be varied. Variables such as spot size and laser power also affect a particular system design and can be selected based on the desired result. According to these variables, the electromagnetic radiation source can induce electromagnetic radiation in the electromagnetic radiation sensitive composition in accordance with the image data source and information received from the signal processor. In addition, the concentration of leuco dye and / or activator and the degree of proximity to each other can be varied.

  The leuco dye of the present invention can be developed using a laser having a power consumption of 15 to 100 mW, but a laser having a power outside this range can also be used. The spot size can be determined by consideration of the electromagnetic radiation source and can range from about 1 to about 200 μm, although smaller or larger sizes can also be used. In one embodiment, a radiation spot size of about 10 to about 60 μm can also be utilized. In yet another aspect, a spot size of 20 × 50 μm may provide a good balance between resolution and color development speed.

Similarly, the heat flux is also a variable that can be varied, in one embodiment about 0.05-1 J / cm ² and in the second embodiment about 0.05-0.4 J / cm 2. Can be ² . Heat flux in these ranges is less than about 1000 microseconds / dot in some embodiments, less than about 500 microseconds / dot in other embodiments, and about 100 microseconds in yet another embodiment. The leuco dye can be developed at a dot / dot or less.

  An example in which these variables are used together is described in one embodiment: a leuco dye composition and activator in about 20 minutes with a spot size of 20 × 50 μm, a 35 mW laser, and 100 microsecond exposure per dot. The included standard CD image surface can be developed. The black image generated in this embodiment can have a high optical density greater than about 1.3. An optical density of about 1.4 or higher can also generally be achieved. One skilled in the art can adjust these variables to achieve various resolutions and development times.

  Other variations may be implemented, including the addition of non-leuco colorants that impart the desired additional color to the image. For example, opacifier pigments or other non-leuco colorants can be used to give the optical disc a background color. A layer of an electromagnetic radiation sensitive composition (which may comprise an activator layer and a leuco dye layer or may be a single layer in which two layers are mixed), as long as it does not adversely affect the development of the leuco dye, or A non-leuco colorant can be added to the protective layer. Thereby, when the black leuco dye part is developed, a black image with a colored background can be produced. Examples of opacifiers include calcium carbonate, titanium dioxide, and other known opacifiers. Examples of other non-leuco colorants include dyes or other pigments. In other words, if a colored background that remains independent of the color development of the leuco dye is desired, opacifier pigments, other pigments, and / or dyes can be mixed in the carrier to give the desired color.

  For preparing black forming leuco dyes, the dyes can be prepared in a solution that is substantially transparent or translucent. Any suitable carrier can be used such as a surfactant compatible with the specific black leuco dye selected. When preparing a black leuco dye in solution, it is desirable to underprint a colored coating on at least a portion of the substrate below the leuco dye solution. The optional colored coating produces a background color that is visible below the solution layer. The colored coating can include various non-leuco colorants such as other pigments and / or dyes. Alternatively, non-leuco colorants can be added to the data layer to produce the desired background color. The activator can be mixed into the solution, such as dispersed, or coated on the substrate before or after the solution is coated thereon. When pre-printing the background color, the aforementioned coatings and compositions can be applied to the substrate using a variety of known techniques such as screen printing, spin coating, sputtering, or spray coating. Each coating can be applied and then dried sequentially.

  About 5 g of ground 4-benzyloxybenzoate containing 0.05% IR783 activator powder was added to an UV curable mixture consisting of acrylate monomers and oligomers (commercially available under the trademark NOR-COTE CDG000 UV-lacquer) 15 Dissolved in 3 g to form a solution. Next, 2′-anilino-3′-methyl-6 ′-(dibutylamino) fluorane (BK-400 available from Nagase Co., Ltd.) having the following structure and having an average particle size of less than about 5 μm 14.5 g of leuco dye) was added to the solution.

  As activator, 1.9 g of pure bisphenol-A having an average particle size of less than about 5 μm was added to the solution. The solution was made into a fine paste and screen printed onto a substrate at a thickness of about 7 μm to form an imaging medium. The coating on the medium was then cured by ultraviolet radiation using a mercury lamp.

  The resulting leuco dye-containing layer was developed using a 780 nm 45 mW laser. An exposure time of about 20 microseconds to 100 microseconds produced marks of about 20 μm × 45 μm. The developed image was generated without using a printing medium and exhibited a high optical density.

  About 2 g of dibenzyl oxalate powder was heated to about 85 ° C., which is sufficient for the powder to melt. 20 g of phenol, 4,4′-sulfonylbis (2- (2-propenyl) activator (commercially available under the trademark TG-SA) having the following structure and 1.2 g of IR absorption in the melted powder Agent IR780 was added.

  The resulting composition was cooled and crushed into a fine powder. Next, 1.8 g of fine powder was dissolved in 15.3 g of carrier NOR-COTE CDG000 UV-lacquer to form a solution. Next, under the trademark S-205, Nagase Co. , Ltd., Ltd. 15 g of a black leuco dye ((2-anilino-3-methyl-6- (N-ethyl-N-isoamylamino) fluorine) having the following structure, which is commercially available from:

  The black leuco dye had an average particle size of less than about 5 μm. In addition, 2.0 g of pure bisphenol-A having an average particle size of less than about 5 μm was added to the solution to form a mixture. The mixture was made into a fine paste and screen printed onto the substrate at a thickness of less than about 7 μm to form an imaging medium. The coating on the medium was then cured using ultraviolet radiation from a mercury lamp.

  The leuco dye was then developed on the resulting coated substrate using a 780 nm 45 mW laser. With an exposure time of about 60 microseconds to 100 microseconds, marks of about 20 μm × 45 μm were produced. The developed image was generated without using a printing medium and exhibited a high optical density.

  Indocyanine green (1.5 g of a 10% solution) dissolved in deionized water is thoroughly mixed with 50 g of a screen printing paste commercially available from Savoir Fair, Novato, Calif. Under the trademark LASCAUX to obtain a paste mixture. Was generated. About half of the paste mixture was combined with 17 g of ground black leuco dye (S205 as in Example 2). The leuco dye was previously ground as an aqueous slurry to an average particle size of less than about 5 μm and dried to about 50% solids. Next, the paste mixture and the leuco dye were sufficiently mixed using a roller mill. The remaining portion of the paste mixture was then combined with 33 g of benzyl 4-hydroxybenzoate and mixed well. Benzyl 4-hydroxybenzoate was prepared by grinding the particles to an average particle size of less than 11 μm and drying to about 50% solids. The resulting combination mixture was then roll milled to fully homogenize the ingredients and reduce the average particle size. The average fineness of the resulting mixture was less than about 2 μm. The viscosity of the mixture was between 50,000 and 160,000 cps at 1 rpm and the curve slope for 10 rpm / 1 rpm was measured to be greater than 5.0. The mixture was screen coated on one side of the CD and dried under vacuum at 45 ° C.

  The leuco dye was then developed on a CD substrate using a 780 nm 45 mW laser with an exposure time of 280 microseconds. The image printed on the CD was a high optical density black mark with dimensions of about 20x50 microns and had a green background.

  It should be understood that the configurations referenced above are illustrative of the application of the principles of the present invention. Although the invention has been illustrated in the drawings and described above with respect to exemplary embodiments of the invention, numerous modifications and alternative constructions may be devised without departing from the spirit and scope of the invention. It will be apparent to those skilled in the art that many modifications can be made without departing from the principles and concepts of the invention as set forth in the claims.

Schematic of a system for label printing on a substrate according to an embodiment of the invention Sectional view of a portion of an optical disc, according to some exemplary embodiments of the invention Sectional view of a portion of an optical disc, according to some exemplary embodiments of the invention Sectional view of a portion of an optical disc, according to some exemplary embodiments of the invention

Claims (15)

An optical disk comprising an optical disk substrate coated thereon with an electromagnetic radiation sensitive composition, the electromagnetic radiation sensitive composition comprising:
a) a leuco dye capable of forming a black image upon color development, which is an isobenzofuranone-containing dye,
b) an activator configured to react with the leuco dye;
c) Electromagnetic radiation absorber mixed with or in thermal contact with the leuco dye and thermally active under the influence of electromagnetic radiation sufficient to promote the reaction Agent,
An optical disc comprising:   The optical disk of claim 1, wherein the absorbent is mixed with the leuco dye, and the absorbent is thermally active under the influence of electromagnetic radiation.   The electromagnetic radiation absorber is included in a first layer and the leuco dye and the activator are included in a second layer, and the second layer is activated when the absorber is activated by electromagnetic radiation. The optical disk of claim 1 configured with respect to the first layer to be in thermal contact with a leuco dye.   The optical disk of claim 1, wherein the electromagnetic radiation is in the form of a laser.   The optical disk of claim 1, wherein the electromagnetic radiation sensitive composition further comprises a non-leuco dye. A system for label printing on a substrate,
a) an image data source;
b) a substrate having an electromagnetic radiation sensitive composition coated thereon, wherein the electromagnetic radiation sensitive composition comprises:
i) a leuco dye that is an isobenzofuranone-containing dye capable of forming a black image upon color development;
ii) an activator configured to react with the leuco dye;
iii) Electromagnetic radiation absorption mixed with or in thermal contact with the leuco dye, which is thermally active under the influence of electromagnetic radiation sufficient to promote the reaction Agent,
A substrate comprising:
c) an electromagnetic radiation source operatively connected to the image data source and configured to induce electromagnetic radiation in the electromagnetic radiation sensitive composition;
Including the system. The system of claim 6, wherein the electromagnetic radiation source is in the form of a laser source capable of producing a heat flux of 0.05 to 1.0 J / cm ² .   The system of claim 6, wherein the black image has an optical density of at least 1.3.   The system of claim 6, wherein the substrate has an underprinted colored layer below the electromagnetic radiation sensitive composition.   The system of claim 6, wherein the substrate is an optical disc. A method of label printing on an optical disc,
a) applying an electromagnetic radiation sensitive composition to the surface of the optical disc, the composition comprising a black leuco dye, an activator, and an electromagnetic radiation absorber, wherein the leuco dye comprises A step, which is a benzofuranone-containing dye,
b) transferring image data from the data source to an electromagnetic radiation source configured to generate electromagnetic radiation;
c) Discoloring at least a portion of the electromagnetic radiation sensitive composition by exposure to electromagnetic radiation at a predetermined frequency, intensity, time, and spot size to produce a visible image on the optical disc. When,
Including the method.   12. The method for label printing on an optical disc according to claim 11, wherein the electromagnetic radiation sensitive composition is formed of adjacent layers comprising a layer containing a leuco dye and a layer containing an absorbent.   12. The step of transferring the image data further comprises digitizing the data to correspond to a spiral path that matches a path followed by an electromagnetic radiation source with respect to an uppermost surface of the optical disc during rotation. A method of label printing on the optical disc described in 1.   12. The method of label printing on an optical disc according to claim 11, wherein the electromagnetic radiation sensitive composition further comprises a non-leuco colorant. The leuco dye is

15. The optical disc, system or method according to any one of claims 1 to 14, selected from the group consisting of:

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