Device and method for verifying valuable documents

1. A method for automatically checking sheet-shaped documents of value, comprising the following steps:

defining the position of two measuring tracks of a measuring apparatus in such a way that at least the presence of two different not visible spectral properties of a predetermined type of authentic documents of value can be checked, wherein the two different not visible spectral properties are provided in certain areas of the documents of value, and said checking of at least the presence of the two different not visible spectral properties can be conducted independently of whether the document of value is in a first position or in a second position rotated by 180° in relation to the document plane,

irradiating the document of value along the measuring tracks,

capturing measuring values of the irradiated document of value along the measuring tracks, wherein at least in a part of the measuring tracks the measuring is carried out at least two spectrally spaced-apart measuring frequencies, and

ascertaining, whether the at least two different spectral properties of the predetermined type of authentic documents of value were captured.

2. The method according to claim 1 , wherein the presence of documents of value is checked, in which an infrared absorber is present only in at least a partial surface of the entire surface of the document of value and the position of the measuring track is determined in such a way that the presence of the infrared absorber in the specific partial surface can be checked.

3. The method according to claim 1 , wherein at least one of the measuring frequencies and the position of the measuring track are determined in such a way that the presence of an infrared absorber in a specific partial surface is checked by comparing measuring values of a measuring track at least two different frequencies with a spectral course to be expected for authentic documents of value.

4. The method according to claim 1 , wherein a second spectral property in another infrared-absorber-free partial surface is checked by comparing measuring values at least one frequency with another spectral property to be expected for authentic documents of value.

5. The method according to claim 1 , wherein a varying number of measuring frequencies is necessary in order to check the presence of the different spectral properties, and/or at least a part of the measuring tracks is disposed symmetrical in relation to the position of the document of value to be checked.

6. The method according to claim 1 , wherein with authentic documents of value the infrared absorber is only present and checked in a partial surface of at least one of the substrate of the document of value and the printed image of the document of value, the partial surface having been produced with the help of a process selected from the group consisting of steel gravure printing, letterpress printing, indirect relief printing and offset printing, said partial surface being part of at least one of a graphic structure, a currency detail, a signature, a portrait image, a bank seal, a date of issue, and a watermark.

7. The method according to claim 1 , wherein a first of the spectral properties to be checked is a check regarding the presence of an infrared absorber and a second spectral property to be checked is a check regarding the presence of an infrared section in the surface of the document of value.

8. A method for automatically checking sheet-shaped documents of value, comprising the following steps:

defining the position of two measuring tracks of a measuring apparatus in such a way that at least the presence of two different not visible spectral properties of a predetermined type of authentic documents of value can be checked, and said checking conducted independently of whether the document of value is in a first position or in a second position rotated by 180° in relation to the document plane, wherein the position of the two measuring tracks is defined using data of not visible spectral properties of the predetermined type of authentic documents of value,

irradiating the document of value along the measuring tracks,

capturing measuring values of the irradiated document of value along the measuring tracks, wherein at least in a part of the measuring tracks the measuring is carried out at least two spectrally spaced-apart measuring frequencies, and

ascertaining, whether the at least two different spectral properties of the predetermined type of authentic documents of value were captured.

9. The method according to claim 8 , wherein the presence of documents of value is checked, in which an infrared absorber is present only in at least a partial surface of the entire surface of the document of value and the position of the measuring track is determined in such a way that the presence of the infrared absorber in the specific partial surface can be checked.

10. The method according to claim 8 , wherein at least one of the measuring frequencies and the position of the measuring track are determined in such a way that the presence of an infrared absorber in a specific partial surface is checked by comparing measuring values of a measuring track at least two different frequencies with a spectral course to be expected for authentic documents of value.

11. The method according to claim 8 , wherein a second spectral property in another infrared-absorber-free partial surface is checked by comparing measuring values at least one frequency with another spectral property to be expected for authentic documents of value.

12. The method according to claim 8 , wherein a varying number of measuring frequencies is necessary in order to check the presence of the different spectral properties, and/or at least a part of the measuring tracks is disposed symmetrical in relation to the position of the document of value to be checked.

13. The method according to claim 8 , wherein with authentic documents of value the infrared absorber is only present and checked in a partial surface of at least one of the substrate of the document of value and the printed image of the document of value, the partial surface having been produced with the help of a process selected from the group consisting of steel gravure printing, letterpress printing, indirect relief printing and offset printing, said partial surface being part of at least one of a graphic structure, a currency detail, a signature, a portrait image, a bank seal, a date of issue, and a watermark.

14. The method according to claim 8 , wherein a first of the spectral properties to be checked is a check regarding the presence of an infrared absorber and a second spectral property to be checked is a check regarding the presence of an infrared section in the surface of the document of value.