Method of generating a copy detection pattern (CDP), or a portion of a CDP, for printing on a substrate, comprising: generating a plurality of digital files, each of an image comprising an at least partially random two dimensional (2D) distribution of dark and light pixels, and applying an optimization process configured to increase a copy detection performance of a resultant digital file output by the method, said optimization process comprising a) comparing a copy detection performance of a first of said plurality of digital files, which constitutes a test digital file, with a copy detection performance of another of said plurality of digital files modified with respect to said test digital file, which constitutes a modified digital file, b) replacing the test digital file with said modified digital file, if the copy detection performance of said modified digital file is greater than the copy detection performance of the test digital file, in which case the modified digital file becomes the test digital file, and c) repeating steps a) and b) until a termination condition is met.

A redundantly printed security-enhanced document, printing method and system ensure the meaning of the information imparted by variable indicia printed by redundant printing on the document with removable scratch-off coatings. By printing the variable indicia with multiple colors, redundancy and integrity of the intended indicia is achieved. Additionally, inverted color indicia countermeasures to pinprick attacks are also disclosed. The redundantly printed document, methods and systems enhance the overall appearance of the redundantly printed document, and reduce possible consequences resulting from misprinted variable indicia. The resultant printed process color indicia maintains a grayscale equivalent level of a process color greater than or equal to the measured grayscale equivalent level of the substrate surface plus an additional contrast delta of 15%.

An optical article printed on a substrate may include an organic binder; and a plurality of reflective magnetic platelets provided in the organic binder, wherein the plurality of reflective magnetic platelets are substantially aligned in accordance with at least part of a surface of revolution, and wherein the plurality of reflective magnetic platelets are aligned to cause a first reflective effect of the optical article when the substrate is rotated around a first axis and to cause a second reflective effect of the optical article when the substrate is rotated around a second axis, wherein the first reflective effect is different from the second reflective effect.

An optical article printed on a substrate may include an organic binder; and a plurality of reflective magnetic platelets provided in the organic binder, wherein the plurality of reflective magnetic platelets are substantially aligned in accordance with at least part of a surface of revolution, and wherein the plurality of reflective magnetic platelets are aligned to cause a first reflective effect of the optical article when the substrate is rotated around a first axis and to cause a second reflective effect of the optical article when the substrate is rotated around a second axis, wherein the first reflective effect is different from the second reflective effect.

In a first image formation mode, an image is formed with a first development contrast C1 and a specific dot pattern is formed with a second development contrast C2, which is lower than the first development contrast C1; in a second image formation mode, an image is formed with a third development contrast C3 and a specific dot pattern is formed with a fourth development contrast C4, which is lower than the third development contrast C3; and when C1 (=C2/C1) denotes a ratio between the second development contrast C2 and the first development contrast C1, and C2 (=C4/C3) denotes a ratio between the fourth development contrast C4 and the third development contrast C3, C2<C1 is satisfied.

In a first image formation mode, an image is formed with a first development contrast C1 and a specific dot pattern is formed with a second development contrast C2, which is lower than the first development contrast C1; in a second image formation mode, an image is formed with a third development contrast C3 and a specific dot pattern is formed with a fourth development contrast C4, which is lower than the third development contrast C3; and when C1 (=C2/C1) denotes a ratio between the second development contrast C2 and the first development contrast C1, and C2 (=C4/C3) denotes a ratio between the fourth development contrast C4 and the third development contrast C3, C2<C1 is satisfied.

An electrophotographic printing system includes circuitry configured to: select, in accordance with an operation to an input device, a mask pattern made up of first toner representing black by a combination of a plurality of color toners, the mask pattern being overlaid on an image area of a target image to be concealed within image data; and generate, based on the image data, print data for overlaying and printing the selected mask pattern on the image area.

In a general aspect, identity markers containing identity-forming particles are created by electrostatic printing processes. In some aspects, a toner mixture is received on an electrostatically charged surface of an image transfer drum in an electrostatic printer system. The toner mixture includes fusible particles and diamond particles. The toner mixture is held to the electrostatically charged surface by an electrostatic force. The toner mixture is transferred onto a substrate from the electrostatically charged surface of the image transfer drum. The toner mixture is bonded to the substrate by operation of a fuser assembly of the electrostatic printer system. When the toner mixture is bonded onto the substrate, the fusible particles fuse to each other, thereby forming a host matrix that secures the diamond particles at fixed locations in the host matrix.

The scanning optical device (6) includes a light source, a deflector (30) configured to rotate on a horizontal surface around a rotating shaft extending in a vertical direction and an optical box (50) in which the light source, the deflector (30), and the optical components groups (40) are housed and supported by the frame (60). A heat sink (36) is disposed between the deflector (30) and the frame (60). A first protrusion (37) extending on an extension line of the rotating shaft of the deflector (30) is formed in the heat sink (36). A first engaging hole (61) with which the first protrusion (37) engages is formed in the frame (60).

An image forming apparatus includes an image forming unit and developing containers. The image forming unit includes developing stations to form an image on a print medium with toners, based on input image data. The developing containers contain the toners and are attachable to and detachable from the developing stations. The developing containers include a first developing container containing a first toner and a second developing container containing a second toner having a higher luminescence intensity under invisible light than the first toner. The first toner and the second toner are toners that form an image having a higher luminescence intensity under the invisible light than under visible light. The image forming unit adheres the second toner to the print medium before adhering the first toner when the image forming unit superimposes the first toner and the second toner one atop another on the print medium.