Printed material detection apparatus for detecting management information, image forming apparatus, printed material detection system and recording material for the same

1. A printed material detection apparatus comprising:

a detector configured to transmit radio waves whose frequency is 1 GHz or more and 5 THz or less toward a printed material and to detect reflection or absorption of the radio waves, wherein

the detector comprises at least two sets of antennas configured to transmit and receive the radio waves, and

the at least two sets of antennas are arranged on different planes and are arranged so that center lines of the radio waves transmitted from the at least two sets of the antennas form an angle of 90° or less.

2. The printed material detection apparatus according to claim 1 , wherein

the radio waves transmitted by the detector are millimeter waves or sub-millimeter waves.

3. The printed material detection apparatus according to claim 1 , wherein

the at least two sets of antennas include three sets of antennas, and

the three sets of antennas are arranged so that center lines of the radio waves transmitted from the three sets of the antennas are arranged at an angle of 90° or less in an X-direction, a Y-direction and a Z-direction which are any three-dimensional coordinates.

4. A printed material detection apparatus comprising:

a detector configured to transmit radio waves whose frequency is 1 GHz or more and 5 THz or less toward a printed material and to detect reflection or absorption of the radio waves; and

a radio wave absorbing body, wherein

the detector comprises a transmitter configured to transmit the radio waves, and

the radio wave absorbing body is arranged such that the radio wave absorbing body and the transmitter sandwich a position through which the printed material passes.

5. An image forming apparatus comprising:

a first image former configured to form an image on a print medium using a first recording material;

a second image former configured to provide management information to the print medium using a second recording material having a reflectance or absorptivity of radio waves different from a reflectance or absorptivity of radio waves of the first recording material;

a management information detector configured to detect whether the management information is provided to the print medium; and

a collector configured to collect the print medium in a case where the management information detector does not detect the management information on the print medium to which the management information is to be provided.

6. The image forming apparatus according to claim 5 , wherein

the second recording material reflects or absorbs at least a part of radio waves whose frequency is 1 GHz or more and 5 THz or less.

7. The image forming apparatus according to claim 6 , wherein

the second recording material reflects or absorbs at least a part of millimeter waves or sub-millimeter waves as the radio waves.

8. The image forming apparatus according to claim 5 , wherein the first image former comprises:

a provider configured to provide an image to the print medium, and

a heater configured to heat the print medium,

the heater is arranged downstream with respect to the provider in a conveying direction of the print medium, and

the second image former is arranged upstream with respect to the provider in the conveying direction of the print medium.

9. The image forming apparatus according to claim 8 , wherein

the second recording material is an invisible material.

10. The image forming apparatus according to claim 5 , wherein

the first image former comprises a provider configured to provide the print medium with an image, and

the second image former is arranged downstream with respect to the provider in a conveying direction of the print medium.

11. The image forming apparatus according to claim 5 , wherein

the second image former is arranged at a position facing a rear surface of the print medium.

12. The image forming apparatus according to claim 11 , wherein

the second recording material is a visible material.

13. The image forming apparatus according to claim 5 , wherein

the management information is provided as a solid image.

14. The image forming apparatus according to claim 5 , wherein

the management information is provided as an image having a mesh pattern, the mesh pattern having a mesh size corresponds to a wavelength of the radio waves.

15. A printed material detection system comprising:

the image forming apparatus according to claim 5 ; and

a printed material detection apparatus including a detector configured to transmit radio waves whose frequency is 1 GHz or more and 5 THz or less toward a printed material and to detect reflection or absorption of the radio waves.