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US-12624238-B2 - Printed material

US12624238B2US 12624238 B2US12624238 B2US 12624238B2US-12624238-B2

Abstract

A printed material ( 100 ) has a base substance ( 1 ), an absorption part ( 22 ) (a near infrared ray absorbing layer ( 3 )) that is provided on the base substance ( 1 ) to contain a near infrared ray absorbing material, and a code shape ( 20 ) that is formed in a predetermined shape from the absorption part ( 22 ) or by covering a part of the absorption part ( 22 ) and that outputs code information (CI), upon irradiation with light of near infrared rays, as reflected light of the light of near infrared rays, where in the near infrared ray absorbing material, in a case where an integral value of transmittance of visible light at 400 nm to 750 nm is denoted as a first integral value X1, and an integral value of transmittance in a 20 nm width that is centered on a predetermined wavelength λ of the light of near infrared rays is denoted as a second integral value X2, a ratio R=X2/X1 between the second integral value X2 and the first integral value X1 is 0.09 or more.

Inventors

  • Takamichi Amako
  • Hiroyuki Sasaki

Assignees

  • YAMAMOTO CHEMICALS, INC.

Dates

Publication Date
20260512
Application Date
20211125
Priority Date
20201216

Claims (9)

  1. 1 . A printed material comprising: a base substance; a near infrared ray absorbing layer that is provided on the base substance and contains a near infrared ray absorbing material; and a code shape that is formed in a predetermined shape from the near infrared ray absorbing layer or by covering a part of the near infrared ray absorbing layer and that outputs code information, upon irradiation with a near infrared ray, as reflected light of the near infrared ray, wherein in the near infrared ray absorbing material, in a case where an integral value of transmittance of visible light at 400 nm to 750 nm is denoted as a first integral value X1, and an integral value of transmittance in a 20 nm width that is centered on a predetermined wavelength λ of the near infrared ray is denoted as a second integral value X2, a ratio R=X2/X1 between the second integral value X2 and the first integral value X1 is 0.09 or more.
  2. 2 . The printed material according to claim 1 , wherein the near infrared ray absorbing layer is provided on the base substance to cover an entire region in which the code shape is provided.
  3. 3 . The printed material according to claim 1 , wherein a value of the first integral value X1 is 17,000 or less.
  4. 4 . The printed material according to claim 1 , wherein the second integral value X2 is calculated in a case where the predetermined wavelength λ is at least one of 780 nm, 830 nm, and 850 nm.
  5. 5 . The printed material according to claim 1 , wherein the near infrared ray absorbing material is a naphthalocyanine-based compound.
  6. 6 . The printed material according to claim 5 , wherein the naphthalocyanine-based compound is a vanadyl naphthalocyanine compound which may have a substituent.
  7. 7 . The printed material according to claim 1 , wherein the near infrared ray absorbing material is a pigment and has a particle diameter D 50 of 0.05 μm or more and 1.0 μm or less.
  8. 8 . The printed material according to claim 1 , further comprising: an interposition layer having a reflectivity of light of near infrared rays of 70% or more, between the base substance and the near infrared ray absorbing layer.
  9. 9 . The printed material according to claim 1 , further comprising: an image layer that covers the code shape, which has a transmittance of near infrared rays of 80% or more.

Description

TECHNICAL FIELD The present invention relates to a printed material. BACKGROUND ART For the purpose of ensuring the security of documents and embedding additional data, there is known a technique for printing characters or the like with an infrared ray absorbing material, irradiating the printed matter with infrared rays, and reading the characters and the like printed with the infrared ray absorbing material. As such a technique, there is, for example, an image forming apparatus that forms a code image on a recording printed material using a printing toner (an IR toner) in which a near infrared ray absorbing material is used, for the purpose of preventing unauthorized copying (for example, See Patent Document 1). RELATED DOCUMENT Patent Document [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-117352 SUMMARY OF THE INVENTION Technical Problem In recent years, security interest has increased, and in various fields, there is a demand for a technique for embedding, in a printed material, information (characters, codes, or the like) invisible to humans. In particular, in a case where invisible information (characters, codes, or the like) is provided on a printed material using a near infrared ray absorbing material, there has been a demand for a technique capable of stably recognizing the information. The present invention has been made in consideration of such circumstances described above, and an object of the present invention is to provide a technique for stably recognizing invisible information provided on a printed material using a near infrared ray absorbing material. Solution to Problem According to the present invention, there is provided a printed material including a base substance, a near infrared ray absorbing layer that is provided on the base substance and contains a near infrared ray absorbing material, and a code shape that is formed in a predetermined shape by the near infrared ray absorbing layer or by a shielding layer that covers a part of the near infrared ray absorbing layer and that outputs code information, upon irradiation with a near infrared ray, as reflected light of the near infrared ray, in which in the near infrared ray absorbing material, in a case where an integral value of transmittance of visible light at 400 nm to 750 nm is denoted as a first integral value X1, and an integral value of transmittance in a 20 nm width that is centered on a predetermined wavelength λ of the near infrared ray is denoted as a second integral value X2, a ratio R=X2/X1 between the second integral value X12 and the first integral value X1 is 0.09 or more. Advantageous Effects of Invention According to the present invention, it is to realize a technique for stably recognizing invisible information provided on a printed material using a near infrared ray absorbing material. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining an outline of operations carried out by a printed material in which invisible information is embedded and a device that reads the information in the first embodiment. FIG. 2A is a plan view of the printed material in the first embodiment. FIG. 2B is a plan view of the printed material in the first embodiment. FIG. 3A is a cross-sectional view of the printed material in the first embodiment. FIG. 3B is a cross-sectional view of the printed material in the first embodiment. FIG. 4A is a view for explaining a state of the absorption and reflection of near infrared rays in a code shape in the first embodiment. FIG. 4B is a view for explaining a state of the absorption and reflection of near infrared rays in the code shape in the first embodiment. FIG. 5 is a view for explaining a manufacturing method for a printed material in the first embodiment. FIG. 6 is a view for explaining the manufacturing method for a printed material in the first embodiment. FIG. 7A is a cross-sectional view of a printed material in the second embodiment. FIG. 7B is a cross-sectional view of a printed material in the second embodiment. FIG. 8 is a view showing a transmission spectrum in Example 9, where the transmission spectrum (T %) is measured at a sampling interval of 1 nm in a range of wavelengths from 300 nm to 1,000 nm, and the transmittance at 780 nm is 10%. FIG. 9 is a view showing a transmission spectrum in Example 9, where the transmission spectrum (T %) is measured at a sampling interval of 1 nm in a range of wavelengths from 300 nm to 1,000 nm, and the transmittance at 830 nm is 10%. FIG. 10 is a view showing a transmission spectrum in Example 9, where the transmission spectrum (T %) is measured at a sampling interval of 1 nm in a range of wavelengths from 300 nm to 1,000 nm, and the transmittance at 850 nm is 10%. FIG. 11 is a graph showing a difference in a spectral distribution of light transmittance depending on the particle diameter in Examples. FIG. 12 is a graph showing the ratio R (=X2/X1) for each particle diameter in Examples. FIG. 13 is a graph showing