A security document has security printing formed as a moire pattern of two superimposed sets of generally parallel lines. In each line set the line spacing varies progressively along the length of the lines so that each line set has one or more areas in which the line frequency is low and individual lines can be seen with the naked eye, and one or more further areas of high line frequency in which individual lines can only be readily distinguished by using magnification. Futhermore, the thickness of each line varies progressively between relatively large and relatively small values corresponding respectively to the areas of low and high line frequency, the ration of line spacing to line thickness being approximately constant so that the color or tonal density of the security printing is approximately uniform. For additional security the individual line sets are printed in inks of which the colors can be differentiated by the naked eye but not by a reproducing machine used for counterfeiting. One or both of the line sets may additionally or alternatively be printed in an ink having an anti-fraud characteristic such, for example, as water-fugitivity, solvent-sensitivity or UV fluroescence.
Commercially available pigments mixed with fluorescence compound to obtain print stuff mixtures for transfer thereafter to mattes. The print stuff mixtures obtainable thereby are used to print securitY and face-value documents which will be color copier resistant, that is, not be accurately reproducible or replicable by a photocopier. An empirical test is provided which will allow the ordinary skilled printer to determine the best titer of commercially available fluorescence to be used in the ink/pigment mixing scheme.
A photocopy-resistant document which has a background pattern or logo which is printed with solvent-sensitive, dye based ink and a method of making such a document. The presence of this photocopy-resistant background pattern or logo makes it impossible for a would-be forger of a face-value note such as a bank check to duplicate the original document as a color photocopy. It also makes it impossible for a printing plate to be made based on a photocopy of the document. Besides being photocopy-resistant, the indicia printed with the solvent-sensitive ink are washed away when acetone or bleach solvent is applied to the surface of the document. A fluorescence material can also be added to the solvent-sensitive ink to make the indicia printed with the ink fluorescent under black light.
A fluorescent security system for retail transactions which maximizes the printed character or image life of a combination visible/fluorescent inked printing ribbon while ensuring that the fluorescent security life of the combination visible/fluorescent inked printing ribbon will outlast the visible life for printed characters or images under normal lighting conditions. This fluorescent security system for transaction records consists of a fabric ribbon, a dual-roll foam reinker and an optical filter. The fabric ribbon is initially inked with fluorescent ink richer in visible color dye than a normal fluorescent ink to enhance the printed character or image life of the combination visible/fluorescent inked printing ribbon. A dual-roll foam reinker consisting of an inner roll and an outer roll positioned concentric to the inner roll is used to replenish ink depleted from the fabric ribbon during the printing process. The inner roll and the outer roll can have the same or different pore sizes.
A photocopy-resistant document which has a background pattern or logo which is printed with solvent-sensitive, dye based ink and a method of making such a document. The presence of this photocopy-resistant background pattern or logo makes it impossible for a would-be forger of a face-value note such as a bank check to duplicate the original document as a color photocopy. It also makes it impossible for a printing plate to be made based on a photocopy of the document. Besides being photocopy-resistant, the indicia printed with the solvent-sensitive ink are washed away when acetone or bleach solvent is applied to the surface of the document. A fluorescence material can also be added to the solvent-sensitive ink to make the indicia printed with the ink fluorescent under black light.
A security ink is provided containing a colored dye, a colored pigment, and a fluorescent pigment. The ink may be printed on a number of security documents such as checks and may be passed through printing devices such as laser printers without the problem of damage to the ink the printed image, or the printer. The fluorescent pigment in the ink will fluoresce when the document is exposed to ultraviolet light and may be used to provide an authentication feature.
