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US 2019/0196382 A1Published application
Image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsMasato Tanaka, Keiji Kunimi
Life of this patent
Estimating the term…
Abstract
An image forming apparatus is provided. The image forming apparatus includes an image forming unit containing a special recording material and circuitry configured to control the image forming unit to form a hardly visible image on a recording medium with the special recording material. The hardly visible image is formed of a halftone dot image comprising isolated dots in a number smaller than that of isolated dots forming a visible image having the same image area ratio as the hardly visible image.
Claims14
An image forming apparatus comprising:
- an image forming unit containing a special recording material;
- and
- circuitry configured to control the image forming unit to form a hardly visible image on a recording medium with the special recording material, the hardly visible image formed of a halftone dot image comprising isolated dots in a number smaller than that of isolated dots forming a visible image having the same image area ratio as the hardly visible image.
An image forming apparatus comprising:
- an image forming unit containing a special recording material;
- and
- circuitry configured to control the image forming unit to form a hardly visible image on a recording medium with the special recording material, the hardly visible image formed of a halftone dot image having a spatial frequency lower than that of a visible image having the same image area ratio as the hardly visible image.
An image forming apparatus comprising:
- an image forming unit containing a special recording material;
- and
- circuitry configured to control the image forming unit to form a hardly visible image on a recording medium with the special recording material,
- wherein a unit image area ratio X of the hardly visible image has a threshold, the unit image area ratio X represented by A/B where A representing an image area ratio of the hardly visible image and B representing the number of isolated dots in the hardly visible image, a spatial frequency of the hardly visible image, or a reciprocal of a granularity of the hardly visible image,
- wherein the threshold is:
- 0.17 or less when no visible image is to be superimposed on the hardly visible image;
- 0.25 or less when a visible image formed with one color recording material is to be superimposed on the hardly visible image;
- and
- 0.5 or less when a visible image formed with two color recording materials is to be superimposed on the hardly visible image.
6 more elements
Dependencies are inferred from the claim text.