JP3285400B2 - Glass for forming infrared absorption mark and ink using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a mark such as an optically identifiable code pattern and a recognition mark by absorbing infrared rays, which is substantially invisible to the naked eye. The present invention relates to an infrared absorbing glass used as a material.

[0002]

2. Description of the Related Art In recent years, barcodes as code patterns using optical reading have been widely used mainly for distribution management systems. For example, barcodes are widely used as optical data carriers such as JAN codes for POS (point of sale) systems, delivery slips, packing slips, and barcode tags for delivery.

As light source light for optical reading of these conventional bar codes, 650 nm, 800 nm or 950 nm is used.
A semiconductor laser or a light emitting diode having an emission wavelength in the vicinity is mainly used. Therefore, since the wavelength range of the light source light is restricted, the barcode has an absorption characteristic in an ink using carbon black having an absorption band in a visible light region or in a cyan / green system red / infrared wavelength region. Printed or printed with ink.

The barcode printing method is letterpress, offset, flexographic, gravure, or silk printing, and is mainly applied to mass printing called source marking. The barcode printing method is dot impact, thermal transfer, direct thermal, electrophotography, ink jet printing, etc., and is mainly applied to individual printing called in-store marking or production of small lot information code labels. .

[0005] However, there is a strong demand for eliminating such visible information codes because they impose design restrictions on printed matter. Therefore, an attempt has been made to make the information code transparent by printing or printing an ink having no absorption band in the visible light region, thereby making it difficult to visually determine the information code.

[0006] Such attempts at transparency are mainly based on the following four points.
Different methods are being considered. (1) A method of forming an infrared / ultraviolet absorption pattern using an ink that mainly absorbs light having a wavelength outside the visible light range, such as infrared light and ultraviolet light: For example, JP-A-63-116286 and JP-A-Hei. 3-154187, JP-A-3-227378, JP-A-3-275389,
This is disclosed in JP-A-4-70349. The ultraviolet absorption pattern is described, for example, in JP-A-63-183675.

(2) Using a fluorescent ink which has no absorption band in the visible light region and is excited by ultraviolet light or infrared light,
Method for forming fluorescent pattern: Pattern printed matter is disclosed in, for example, JP-B-61-18231 and JP-A-3-229389.
No. Pattern transfer ribbons are disclosed in, for example, JP-A-51-78421 and JP-A-51-82109.
JP-A-51-82111, JP-A-51-8211
No. 2, JP-A-55-129264, JP-A-59-54
598, JP-A-60-44160, JP-A-61-21
No. 3195, JP-A-62-111800, JP-A-63-111800
No. 3,319,189.

(3) Method of forming a reflection / scattering pattern using inks having different glosses such as pearl ink and metal ink: A pattern printed matter is disclosed in, for example, JP-A-4-1097.
No. 3, and a pattern transfer ribbon is described in, for example, JP-A-4-144788.

(4) A method of forming an infrared reflection / absorption pattern using a thin film of indium-tin oxide or tin oxide is described in, for example, JP-A-3-290780.

[0010]

SUMMARY OF THE INVENTION The present invention relates to the infrared absorption patterns in the above (1). Conventionally used dyes having an absorption range in the infrared region include cyanine dyes, phthalocyanine dyes, naphthoquinone dyes, anthraquinone dyes, zirol dyes, and triphenylmethane dyes. However, these have a cyan color due to having an absorption band in a wavelength region of 600 nm or more, or have a wavelength of 30 nm in the visible region (380 nm to 700 nm).
It has a slightly reddish cream color due to absorption of ４０40%. Therefore, a completely transparent barcode could not be formed. Furthermore, since these dyes are dyes, there is a disadvantage that light resistance as an ID carrier cannot be expected. In addition, there is a filter using a cyan filter glass as an infrared absorbing pigment. In this case, the glass contains Cu ²⁺ ions and has a wavelength of 550 nm.
Since the absorption started from the sample, the color of cyan was exhibited.

Under such circumstances, in order to provide a transparent invisible bar code, it is desired to provide a material that absorbs infrared rays but does not absorb visible light. Therefore, an object of the present invention is to provide a new pigment material that has absorption only in the infrared region and does not absorb in the visible light region.
That is, the present invention relates to an infrared-absorbing material which is invisible to the naked eye, and which is excellent in infrared absorption properties, weather resistance, light resistance, ink-forming properties, printability, printability and weatherability, and an ink using this material. The purpose is to provide.

By the way, there is a field in which an infrared absorbing material can be used even in a field different from the infrared absorbing code pattern. For example, when an image is formed on a transparent sheet for an overhead projector (OHP) by a copying machine using an optical detection method, the transparent sheet is set for setting the paper feed timing and the like of the transparent sheet. A detection mark is provided at the edge. The optical detection is, for example, L
It is considered that the detection is performed using a combination of the ED and the phototransistor, and an infrared absorbing material can be used as the detection mark.

However, conventionally, for example, Japanese Patent Laid-Open No. 3-99
As described in Japanese Patent No. 878, the detection mark is formed from an opaque material. However, the opaque detection mark is projected together with the target image by the OHP, and there is a disadvantage that the projected image is difficult to see. Therefore, if a detection mark that is transparent but can be optically detected is provided, such a disadvantage is solved.

Therefore, another object of the present invention is to provide a transparent OHP
In order to provide a transparent detection mark that can be applied to a sheet, it is an object to provide a material that absorbs infrared light but does not absorb visible light. That is, an object of the present invention is to provide a material capable of providing a detection mark which is optically detectable by absorbing infrared rays and which is transparent by not absorbing visible light rays, and an ink using the material.

[0015]

According to the present invention, there is provided an infrared-absorbing mark forming method comprising a glass containing a sufficient amount of infrared-absorbing Yb ³⁺ when forming a mark such as a code pattern or a detection mark. About glass. In the present invention, the mark includes a code pattern, a detection mark, and the like.

The glass for forming an infrared-absorbing mark of the present invention is obtained by adding Yb ³⁺ ions, which are rare earth elements, to a glass serving as a base material so as to add infrared-absorbing properties.
The use of glass as the base material allows the glass to have chemical stability and transparency, and Yb ³⁺ to be stably incorporated into the amorphous glass crystal in an ionic state. That's why.

The content of the Yb ³⁺ ion is such that a mark formed by using the glass of the present invention exhibits an infrared absorption amount that is sufficient to read the mark. This depends on the content of the glass of the present invention in the ink for forming a mark, but is preferably, for example, about 5 to 60% by weight.
When the content of the Yb ³⁺ ion is less than 5% by weight, the absorption of infrared rays becomes weak, and as a result, the infrared rays of the ink for forming a mark become insufficient, and the mark may not be distinguished. On the other hand, the higher the content of the Yb ³⁺ ion, the higher the absorption of infrared rays.
Increasing the content of ³⁺ ions tends to improve the water resistance, weather resistance, and the like of the glass. However, when the content of the Yb ³⁺ ion is too large, the Yb ³⁺
It becomes difficult to keep the ions in the glass in the ionic state, and the chemical stability, transparency, and infrared absorption tend to be insufficient. On the other hand, when the content of Yb ³⁺ ions is 60% by weight or less, the chemical stability and transparency of the glass are sufficiently maintained. Incidentally, infrared absorption, because of the strong tendency larger the content of Yb ³⁺ ions, the content of Yb ³⁺ ions is preferably 10 to 60 wt%, more preferably 20 to 60 wt% It is.

The glass materials used for the substrate include the following. (A) oxide glass SiO ₂ , P ₂ O ₅ , Al ₂ O ₃ , Na ₂ O, BaO,
Ba ₂ O ₃ , Li ₂ O, MgO, ZnO, K ₂ O, Pb
_{O, B 2 O 3, Na} 2 B 4 O 7, Tl 2 O, Mo O 3,
TeO ₂ , V ₂ O ₅ , Fe ₂ O ₃ , K ₂ O, CaO, G
eO ₂ , Sb ₂ O ₃ , As ₂ O ₃ , Al (PO ₃ ) ₃ ,
_{SrO, Ti 2 O, ZrO 2} , Y 2 O 3, CeO 2, B
eO, R ₂ O, Ca ₃ (PO ₄ ) ₂ , Na ₄ P ₂ O ₇ ,
AlPO ₄

(B) Fluoride glass BaF ₂ , BeF ₂ , KF, CaF ₂ , NaF, GdF
₃ , ZrF ₄ , AlF ₃ , SnF ₂ , LiF, Hf
F ₄ , LaF ₃ , ZnF ₂ , LuF ₃ , ThF ₄ , Sr
F ₂ , ScF ₃ , YF ₃ , InF ₃

(C) Chalcogen glass S, Se, S-Se, Se-Te, S-Se-Te PS, P-Se, As-S, As-Ss, As- (S
-Se), (P-As) ─Se, As- (Se-T
e), As- (S-Te), (As-Sb) -S, (A
s-Sb) -Se, (As-Bi) -Se, Si-S,
Ge-S, Ge-Se, Ge- (Se-Te), Ge-
PS, Ge-P-Se, Ge-p-Te, Ge-As
-S, Ge-As-S, Ge-As-Se, Ge-As
-Te, Ge-As- (S-Se), Ge-Sb-S,
Ge-Sb-Se, Sn-As-Se, Ga-As-
S, Ga-As-Se, In-As-S, In @ As-
Se, Tl-As-S, TlAs-Se, Tl-As-
Te, Tl-As- (S-Te), Tl-As- (Se
-Te), Cu-As-S, Cu-As-Se, Ag-
As-S, Ag-As-Se, Au-As-S, Au-
As-Se, As-S-Cl, As-S-Br, As-
SI, As-Se-I, As-Te-I, Cd-Ge
-P, Cd-Ge-As, Al-Ge-Se

Among these glass materials, it is preferable to use phosphate glass or fluorophosphate glass from the viewpoint that a relatively large amount of Yb ³⁺ ions can be contained while maintaining the glass state. In particular, phosphate glass and fluorophosphate glass are preferable from the viewpoint of high compatibility with Yb ³⁺ ions.

The glass of the present invention comprises a raw material for the base material and a source of ytterbium (for example, ytterbium oxide) Yb ₂ O
₃ can be mixed, and the glass raw material can be melted and the glass melt can be cooled and drawn into a thin glass plate by drawing or glass beads by water cooling according to the usual glass manufacturing method.

Yb ³⁺ is in the ionic state in the infrared region,
^It has an absorption band based on the transition of ^{3 +} _{2F7 /} ² → _{3F5 /} ² .
Further, unlike the coloring by the transition metal ion, the absorption is not broad because it does not become broad and has no absorption in the visible region.

As shown in FIG. 1, the glass of the present invention containing Yb ³⁺ having such characteristics remarkably absorbs irradiation light in the infrared region having a peak at about 970 nm.
It has no absorption in the visible region from 00 to 700 nm. Therefore, when a barcode is formed with ink or the like using the glass powder of the present invention, a portion of a bar that absorbs (printed portion)
Between the reflection and the space (non-printing part) where reflection occurs, the density of the reflected light of the absorption / reflection of the irradiating infrared light is formed, and the signal of the bar code can be read. Can not. Furthermore, when the detection mark is formed by ink using glass powder, etc., the density of the reflected light of the absorption / reflection of the irradiated infrared light is provided between the detection mark (printed portion) for absorption and the non-printed portion for reflection. Are formed, and the detection mark is recognized, but cannot be visually recognized with the naked eye.

The glass for forming an infrared-absorbing mark of the present invention can be formed by offset printing, thermal transfer printing, or a printing method suitable for printing a code pattern among marks.
When used as a pigment for offset inks, thermal transfer ribbon inks, inkjet inks, and toner inks for injection printing and electrophotographic printing, the glass of the present invention has an average particle diameter of 0.01 μm to 1.6.
It is preferably a powder having a maximum particle diameter of 2 μm or less. Since the printed film thickness or the printed film thickness obtained by the above method is usually about 1 to 2 μm and at most about 3 μm, the printing unevenness can be obtained by setting the average particle size of the glass powder to the submicron order within the above range. It is because it can suppress. The same applies to gravure ink for gravure printing of the detection mark.

The glass powder of the present invention having the above average particle diameter can be produced by pulverizing a glass block using, for example, a jet mill or a ball mill. When a ball mill is used, the entire container is cooled for the purpose of preventing the particles from associating or being denatured due to the incorporation of foreign matter by melting the material by the heat generated when the particles are crushed. It is preferable to pulverize while.

Further, considering the ink properties, for the offset ink, the thermal transfer ribbon ink and the toner ink having a non-polar binder component, a lipophilic coat is applied to the surface of the infrared absorbing glass powder to form a glass for the ink binder. It is preferable to improve the dispersibility of the particles. By improving the dispersibility, the formed mark can be read satisfactorily.

That is, in the offset printing, it is possible to prevent the glass powder from being precipitated from the ink during the printing and the occurrence of a missing state in which the infrared light absorbing portion is not printed. Further, in the thermal transfer ribbon, a uniform ribbon coating of the coat layer can be obtained, and occurrence of transfer failure during printing can be prevented. Furthermore, even in the toner for electrophotographic printing, the content state of the glass powder of the toner ink can be kept uniform,
A mark having a stable absorption level can be obtained.

Typical examples of the coating method for modifying the surface of the infrared absorbing glass powder used for the glass for forming the infrared absorbing mark are listed below. (A) Coating The coating plays a role of a surfactant. As a specific example, for example, dispersants such as fatty acids (low molecular weight / high molecular weight chains), fatty acid salts, and wax can be used.
In particular, by printing the infrared absorbing glass powder coated with a coating agent using a fluorophosphate fatty acid into an offset ink and printing, the printing unevenness on the infrared absorbing pattern printing portion and the detection mark printing portion can be remarkably improved.

(B) Coupling agent The coupling agent binds firmly to the infrared absorbing glass powder and reacts with the polymer. Specific examples include silane compounds, titanium compounds, metal chelate compounds, and the like. (C) Polymerizable monomer A low molecular weight monomer or oligomer is reacted with the surface of the infrared absorbing glass powder to form an irreversible layer. Specific examples include a polymerizable organic acid and a reactive oligomer.

When the glass for forming an infrared absorbing mark of the present invention is used for gravure printing or silk screen printing, the average particle size of the glass powder is not necessarily required to be submicron, but can be up to about 20 μm. That is, when used for gravure printing or silk screen printing, the glass powder of the present invention has an average particle diameter of 0.01 to
Suitably, it is 20 μm. In particular, when screen printing is used for printing the detection mark, the average particle size of the glass powder is, for example, about 3 μm, and at most about 2 μm.
Suitably, it is 0 μm.

In gravure printing, there is no difference in affinity between the ink solvent and the infrared absorbing glass powder.
Therefore, when using the glass powder of the present invention for gravure printing, without coating the surface of the glass powder, in order to prevent the glass powder from settling in the gravure ink, by mixing a surfactant. Can be used as it is. Further, when the glass powder of the present invention is used for silk screen printing, it can be used as it is without coating the surface of the infrared absorbing glass powder in consideration of the printing method and the printing speed.

In the ink of the present invention, the resin constituting the vehicle is generally a natural resin such as protein, rubber, celluloses, shellac, copal, starch, rosin, vinyl resin, acrylic resin, or the like. Styrene resin, polyolefin resin, thermoplastic resin such as novolak phenol resin, resol phenol resin, urea resin, melamine resin, polyurethane resin, epoxy,
Thermosetting resins such as unsaturated polyesters are exemplified. Further, in the vehicle, if necessary, a plasticizer for stabilizing the flexibility and strength of the printed film, a solvent for adjusting the viscosity, a solvent for drying, and an auxiliary such as drying, viscosity, dispersibility, and various reactants. Can be appropriately added.

However, since it is undesirable for the formed mark to adsorb contaminants by the solvent component, it is preferable to use a photopolymerization-curable or electron beam-curable ink that does not use a solvent. The main component of the cured product of these inks is an acrylic resin. Accordingly, the above ink contains an alkyl monomer, and specific examples thereof include the following acrylic monomers that are commercially available.

Examples of the monofunctional acrylate include 2-ethylhexyl acrylate, 2-ethylhexyl EO adduct acrylate, ethoxydiethylene glycol acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and caprolactone adduct of 2-hydroxyethyl acrylate. Phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, nonylphenol EO adduct acrylate,
Acrylate with caprolactone added to nonylphenol EO adduct, 2-hydroxy-3-phenoxypropyl acrylate, tetrahydrofurfuryl acrylate, caprolactone adduct of furfuryl alcohol acrylate, acryloylmorpholine, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclo Pentenyloxyethyl acrylate, isobornyl acrylate, acrylate of adduct of caprolactone of 4,4-dimethyl-1,3-dioxolan, acrylate of adduct of caprolactone of 3-methyl-5,5-dimethyl-1,3-dioxolan, etc. Can be used.

On the other hand, polyfunctional acrylates include hexanediol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol hydroxypivalate diacrylate, and neopentyl glycol hydroxypivalate. A caprolactone adduct diacrylate of
Acrylic acid adduct of diglycidyl ether of 1,6-hexanediol, diacrylate of acetal compound of hydroxypivalaldehyde and trimethylolpropane, 2,2-bis [4- (acryloyloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloyloxydiethoxy, phenyl) methane, diacrylate of hydrogenated bisphenol A ethylene oxide adduct, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, Trimethylolpropane propylene oxide adduct triacrylate, glycerin propylene oxide adduct triacrylate, dipentaerythritol hexaacrylate / pentaacrylate mixture, dipentaery Lower fatty acids and esters of acrylic acid Lithol, dipentaerythritol caprolactone adduct acrylate, tris (acryloyloxyethyl) isocyanurate, and 2-acryloyloxyethyl phosphate may be used.

The inks made of these resins or monomers are solventless, and are cured by causing a chain polymerization reaction by irradiation of electromagnetic waves or electron beams. Among them, for the ultraviolet irradiation type, a photopolymerization initiator and, if necessary, a polymerization inhibitor and a chain transfer agent as a sensitizer and an auxiliary agent are added.

Examples of the photopolymerization initiator include: 1) direct photolysis type arylalkyl ketone, oxime ketone, acylphosphine oxide, etc. 2) radical polymerization reaction type benzophenone derivative, thioxanthone derivative, etc.
3) Cationic polymerization reaction types include aryldiazonium salts, aryliodonium salts, arylsulfonium salts, arylacetophenones and the like, and 4) energy transfer type, 5) photo redox type, and 6) electron transfer type. obtain.

In the case of the electron beam curing type, the same resin or monomer as used in the above-mentioned ultraviolet irradiation type does not require a photopolymerization initiator, and various auxiliaries can be added as needed.

The ink-jet ink may contain water and an aqueous organic solvent in addition to the glass powder of the present invention and the above-mentioned vehicle. The water may have a purity higher than that of ion-exchanged water.

The water-soluble organic solvent is used for the purpose of preventing drying of the ink and imparting permeability.
Polyhydric alcohols such as diethylene glycol, polyethylene glycol and glycerin: N-alkylpyrrolidones: esters such as ethyl acetate and amyl acetate: lower alcohols such as methanol, ethanol, propanol and butanol: ethylene oxide of methanol, butanol and phenol Or glycol ethers such as propylene oxide adducts. These water-soluble organic solvents are not limited to the above-mentioned solvent examples, and may be used alone or in combination of two or more in consideration of the solvent's hygroscopicity, moisture retention, dye solubility and penetrability, ink viscosity and freezing point, etc. Used in. The usage of these water-soluble organic solvents is preferably in the range of 0.1 to 70% by weight of the ink.

In order to satisfy various conditions required for the system of the ink jet recording apparatus, conventionally known additives can be added as components of the ink, if necessary. These additives include alcohol amines and ammonium salts as pH adjusters, and metal hydroxides: organic salts and inorganic salts as resistivity adjusters: antioxidants: preservatives: antifungal agents: sequestering agents And a chelating agent.

In addition to the above composition, polyvinyl alcohol, polyvinyl virolidone, carboxymethyl cellulose, styrene acrylate resin, styrene maleate resin and the like are used to such an extent that clogging of the injection nozzle portion and change in ink ejection direction do not occur. A water-soluble resin can also be added.

The thermal transfer ribbon ink, the gravure ink and the screen ink for printing the detection mark are prepared by blending a synthetic resin, wax, and, if necessary, a solvent or a coloring agent as a vehicle in addition to the glass powder of the present invention. Prepare. An appropriate synthetic resin is used alone or in combination in consideration of the voltage, melting point, and the like of the thermal head. Specific examples include polyethylene, polystyrene, polypropylene, polybutyne, petroleum resin, vinyl chloride resin, polyvinyl alcohol, vinylidene chloride resin,
Examples include methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal, polyvinyl butyral, acetylcellulose plastic, nitrocellulose, and polyacetal. Wax is beeswax, touch wax, Ibota wax, wool wax, shellac wax,
It can be appropriately selected from carnauba wax, montan wax, paraffin wax, candelilla wax, betrolactam, microcrystalline wax and the like.

The solvent is used when the thermal transfer ribbon ink composition is used as an ink which can be applied by a usual printing method. Benzene, xylene, toluene, trichlene, white spirit, ethyl acetate, n-butyl acetate, methanol,
Ethanol, isopropanol, n-butanol, ethylcyclohexane, methylethylketone, ethylcellosolve, butylcellosolve, cyclohexanone and the like are examples. In particular, it is preferable to use methyl ethyl ketone, ethyl acetate, methanol, ethanol, xylene and toluene.

A thermal transfer sheet having the thermal transfer ribbon ink provided on a base film can be provided. As a material for the base film, a commonly used material may be used. Specifically, polyester, polypropylene, cellophane,
Plastic films such as acetate and polycarbonate, and papers such as condenser paper and paraffin paper can be used.

In the case of the electrophotographic system, the components of the toner ink comprise the glass powder of the present invention, a vehicle, and, if necessary, a charge controlling agent, an offset preventing agent, and an external additive (a fluidizing agent). Examples of the vehicle include thermoplastic resins such as polystyrene resins, styrene-acrylic copolymers, styrene-butadiene copolymers, polyester resins, epoxy resins, and polyolefin resins. Regarding the contact charging property, those having an electron donating substituent such as an amino group are likely to be positively charged, and those having an electron accepting substituent such as a fluorine or carboxyl group are likely to be negatively charged.

As the charge controlling agent, a nigrosine dye or a quaternary ammonium compound is used for positive charging, and a metal complex of alkylsalicylic acid or an azo-containing metal complex is used for negatively charged toner. As other additives, low-molecular-weight polyethylene, low-molecular-weight polypropylene, and the like are used as offset inhibitors for hot roll fixing.

Further, the ink of the present invention may contain an irreversible decolorable colorant in the composition. The decolorizable colorant in this case is a colorant that maintains a visible state in the visible light range and changes irreversibly to an invisible state by an operation for decoloring, for example, an operation such as irradiation with near infrared rays. When a code pattern is formed with an ink composition containing such a decolorizable colorant, a printed image can be identified with the naked eye, and printing accuracy can be improved. Thereafter, the code pattern can be changed to an invisible state by performing a decoloring operation.

Specific examples include the use of a decolorizable colorant IR820B (manufactured by Showa Denko) or a cyanine dye represented by the following structural formula and an organic boron ammonium salt such as tetrabutylammonium / butyltriphenylborate. Some absorb near-infrared light, couple them, and become irreversibly transparent.

[0051]

Embedded image

The glass for forming an infrared absorbing mark of the present invention shows a sharp absorption at about 970 nm as shown in FIG.
Therefore, a code pattern or a detection mark formed by using the glass for forming an infrared absorption mark, as an irradiation light source, for example, a pulsed infrared light of a semiconductor laser or a light of 900 nm or less with respect to the infrared light emission of a light emitting diode. When a lens or the like coated with a band-pass filter that absorbs light of 1000 nm or more is attached to the light receiving sensor side and irradiated with infrared rays, it can be identified as a sharp absorption signal.

In the present invention, a bar code can be exemplified as the code pattern, and the bar code may be a two-dimensional code or the like in addition to a one-dimensional bar code. In particular, the present invention is effective for a two-dimensional code since a high resolution can be obtained.

In the present invention, the detection mark is provided for setting a paper feeding timing of a transparent sheet which is not optically detected when an image is formed by a copying machine using an optical detection method. Mark. The shape of the detection mark and the position on the transparent sheet where the detection mark is provided are not particularly limited. For example, JP-A-58-10655
No. 0, No. 58-105157, No. 59-7367 and JP-A-3-99878.

[0055]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to embodiments.

Example 1 As a phosphate glass raw material powder, lithium carbonate (Li ₂ C
O ₃ ) 12.9 parts by weight, calcium carbonate (CaCO ₃ )
6.25 parts by weight, 6.4 parts by weight of alumina (Al ₂ O ₃ ), 86.88 parts by weight of orthophosphoric acid (H ₃ PO ₄ ) and 24.8 parts by weight of ytterbium oxide (Yb ₂ O ₃ ) powder The resulting mixture was placed in a platinum crucible and melted by heating in an electric furnace heated to 1300 ° C. for 4 hours. Then, it was rapidly cooled to obtain a phosphate glass containing Yb ³⁺ . The composition of the obtained phosphate glass was as follows, and was a glass in which Yb ³⁺ was uniformly dispersed. The content of Yb ³⁺ was 22.3% by weight.

[0057]

[Table 1]

The obtained phosphate glass was roughly crushed and then crushed using a ball mill to obtain a glass powder having an average particle diameter of 1.0 μm. FIG. 1 shows the result of measuring the spectral reflectance of this powder. The measurement was carried out using a Shimadzu self-recording spectrophotometer UV3101PC, and the reflectance of barium sulfate was 1
The test was carried out at 00%.

[0059] except that Yb ₂ O ₃ content of Example 2 Phosphate glass is made to be 15 wt% in the same manner as in Example 1, Yb ³⁺
A phosphate glass powder having a content of 13.4% by weight was obtained. The result of measuring the infrared absorption spectrum of this powder is shown in FIG.

Example 3 A mixture obtained by mixing 9 parts by weight of Ca ₃ (PO ₄ ) ₂ and 1 part by weight of ytterbium oxide (Yb ₂ O ₃ ) powder as a phosphate glass raw material powder was subjected to a hydrogen atmosphere using an electric furnace. The mixture was heated to 400 ° C. over 3 hours while being reduced in the reactor, and further kept at 400 ° C. for 10 hours. Thereafter, the mixture was allowed to cool to obtain a phosphate glass containing 8.9% by weight of Yb ³⁺ .

Separately, a mixture of 8.5 parts by weight of Ca ₃ (PO ₄ ) ₂ and 1.5 parts by weight of ytterbium oxide (Yb ₂ O ₃ ) powder as phosphate glass raw material powder, and Using a mixture of 7.5 parts by weight of Ca ₃ (PO ₄ ) ₂ and 2.5 parts by weight of ytterbium oxide (Yb ₂ O ₃ ) powder, the mixture was heated while being reduced in a carbon monoxide atmosphere, and then released. It cooled to give a phosphate glass containing Yb ³⁺ 13.4 wt%, and Yb ³⁺ a phosphate glass containing 22.3% by weight, respectively. The obtained glass was refluxed and pulverized using a jet mill to have an average particle diameter of 1.1.
A glass powder of μm was obtained.

Example 4 3 parts by weight of the glass powder containing 22.3% by weight of Yb ³⁺ obtained in Example 1 was mixed with 6 parts by weight of an acrylate monomer, 3 parts by weight of a wax, and 0.5 part by weight of a sensitizer. The resulting mixture was added to and mixed with an offset vehicle to prepare an offset ink. This ink was bar-offset-printed on a coated paper by a conventional method.

The obtained bar code could not be recognized by the naked eye. A reading test was performed by using an infrared light emitting diode (SHARP, GL480) as a light source and a CCD linear sensor (SONY, ILX503) as a light receiving unit. As a result, barcode information could be read. Further, the obtained barcode is subjected to a UV irradiation deterioration test using an arc lamp for 100 hours,
In addition, the bar code information could be read even after the chemical deterioration test with a weak acid and a weak alkali, and the weather resistance was excellent.

Example 5 An ink ribbon ink obtained by mill-mixing 5 parts by weight of the glass powder containing 22.3% by weight of Yb ³⁺ obtained in Example 1 with 5 parts by weight of wax was used to obtain a 4 μm thick ink ribbon ink. Was applied to a PET film of Grapea to obtain an ink ribbon. Using this ink ribbon, a barcode was printed on coated paper in a conventional manner.

As in Example 4, the obtained bar code could not be recognized by the naked eye. Further, using the bar code as a light source, infrared light emitting diodes (SHARP, GL)
480) and a CCD linear sensor (S
ONY, ILX503). As a result, barcode information could be read.

Example 6 25.0 parts by weight of the glass powder containing 22.3% by weight of Yb ³⁺ obtained in Example 1 was mixed with 2.4 parts by weight of acrylic resin,
6.4 parts by weight of nitrified cotton, isopropyl alcohol 13.0
Parts by weight, 15.9 parts by weight of denatured ethanol, ethyl acetate 3
By stirring with 1.9 parts by weight and 5.4 parts by weight of propylene glycol monopropyl ether, a gravure ink was obtained.
The obtained ink was gravure-printed on the edge of a PET sheet having a thickness of 100 μm to obtain a transparent OHP sheet having an optical detection mark. The part of the gravure printed detection mark of this OHP sheet was also transparent.

The obtained transparent OHP sheet was subjected to a print test with a copying machine equipped with a photosensitive sheet detecting device. As a result, both the sheet detectability and the paper feeding property were good. Furthermore, since the detection mark portion of the sheet on which the image was formed was transparent, the image when used in OHP was easy to see.

[0068]

According to the present invention, it has no absorption in the visible light region, has a sharp absorption peak in the infrared region, and can retain its infrared absorption characteristics even after deterioration of light resistance and chemical resistance. In addition, it is possible to provide a glass and an ink material excellent for forming an infrared absorption mark such as an infrared absorption code pattern and an infrared absorption detection mark.

[Brief description of the drawings]

FIG. 1 shows a phosphate glass powder containing 13.4% by weight of Yb ³⁺ (Example 2) and a phosphate glass powder containing 22.3% by weight of Yb ³⁺ (Example 1). Shows the spectral reflectance.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C03C 4/08 C03C 3/00 G06K 1/12

Claims (5)

(57) [Claims] 1. An infrared-absorbing mark-forming glass comprising a glass containing an amount of Yb ³⁺ exhibiting sufficient infrared absorption when a mark is formed. 2. The glass according to claim 1, which is a phosphate glass containing 5 to 60% by weight of Yb ³⁺ . 3. The glass according to claim 1, which is a powder having an average particle size of 0.01 to 20 μm. 4. An ink containing the glass powder according to claim 3 and a vehicle. 5. A mark containing an amount of Yb ³⁺ exhibiting sufficient infrared absorption when a mark is formed, and having an average particle size of 0.0
An ink for forming an infrared absorbing mark, comprising a glass powder having a size of 1 to 20 μm and a vehicle.