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US 10,761,468 B2Granted
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.
Claims38
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 a density 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
An image forming apparatus comprising:
- an image forming unit containing a color toner and a special toner;
- and
- circuitry configured to control the image forming unit to form a visible image and a hardly visible image with the color toner and the special toner, respectively, on a recording medium,
- wherein, the circuitry is further configured such that, when the circuitry controls the image forming unit to form the visible image formed of a first halftone dot image and the hardly visible image formed of a second halftone dot image having the same image area ratio as the first halftone dot image, a number of isolated dots in the hardly visible image is smaller than a number of isolated dots in the visible image.
1 more element
An image forming apparatus comprising:
- an image forming unit containing a color toner and a special toner;
- and
- circuitry configured to control the image forming unit to form a visible image and a hardly visible image with the color toner and the special toner, respectively, on a recording medium,
- wherein, the circuitry is further configured such that, when the circuitry controls the image forming unit to form the visible image formed of a first halftone dot image and the hardly visible image formed of a second halftone dot image having the same image area ratio as the first halftone dot image, a spatial frequency of the hardly visible image is lower than a spatial frequency of the visible image.
1 more element
An image forming apparatus comprising:
- an image forming unit containing a color toner and a special toner;
- and
- circuitry configured to control the image forming unit to form a visible image and a hardly visible image with the color toner and the special toner, respectively, on a recording medium,
- wherein, the circuitry is configured such that, when the circuitry controls the image forming unit to form the visible image formed of a first halftone dot image and the hardly visible image formed of a second halftone dot image having the same image area ratio as the first halftone dot image, a granularity of the hardly visible image is lower than a granularity of the visible image. image information.
1 more element
Dependencies are inferred from the claim text.