JP2002351216A - Printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent forgery of securities obtained by printing. SOLUTION: A fluorescent A toner contains a fluorescent material A, and a fluorescent B toner contains a fluorescent material B. These fluorescent materials A and B differ in the degree of change with time of an emission intensity by irradiation of ultraviolet ray. Because of this, the emission intensity by irradiation of ultraviolet ray of a printed article printed with the toner containing the fluorescent materials A and B exhibits more complex change with time compared with the emission intensity of the printed article printed with the toner containing one fluorescent material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forgery preventing method for printing securities on a printing apparatus and a toner loaded in the printing apparatus for the purpose of preventing forgery.

[0002]

2. Description of the Related Art In recent years, the technology of image printing has been applied to the printing of securities such as checks. It is necessary to take countermeasures against forgery in response to this situation.
Conventionally, as the above counterfeiting prevention measure, visual information cannot be obtained under visible light, but an image appears under ultraviolet light, or after penetrating into a marker pen, reacting the treatment liquid with ultraviolet light There were things where images appeared below. These have made the invisible image visible so as to enhance the effect of preventing forgery.

[0003]

In the above-mentioned prior art, a special treatment must be performed later on the printed matter so as to react under ultraviolet rays in order to prevent forgery. And, for this reason, the processing was complicated.

[0004] It is an object of the present invention to prevent counterfeiting of these printed securities when printing securities such as checks using a printing device.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of developing devices are provided,
A printing apparatus in which each of the plurality of developing devices is equipped with a toner containing a fluorescent substance that emits in a visible light region different from each other at the same irradiation wavelength in the ultraviolet region, wherein at least one of the fluorescent toners has an emission intensity. Have the property of changing over time, and are combined so that the degree of change over time of the emission intensity of the fluorescent toner in the plurality of developing devices is different.

[0006] In order to achieve the above object, the present invention is directed to claim 2
In the described invention, a toner containing two or more kinds of fluorescent substances which emit light in different visible light regions at the same irradiation wavelength, wherein at least one of the fluorescent substances has a property that the emission intensity changes with time. The toner is characterized in that the fluorescent substances are combined so that the degree of change of the luminescence intensity of the fluorescent substance with the passage of time is different.

Here, in the first aspect of the invention, only one kind of fluorescent substance is mixed in the toner loaded in each of the plurality of developing devices. On the other hand, according to the second aspect of the present invention, a plurality of fluorescent substances are mixed with one toner. For this reason, the invention according to claim 1 can be applied to a printing device having a plurality of developing devices, whereas the toner according to claim 2 includes one developing device according to claim 3. The present invention is applicable to a printing device and a printing device including a plurality of developing devices.

[0008] If the degree of change of the light emission intensity with the irradiation of ultraviolet light with time is different among a plurality of fluorescent substances, the use of these plural fluorescent substances is more effective than the use of only one fluorescent substance. The change with time of the emission intensity with respect to irradiation becomes more complicated. For this reason, it becomes difficult to reproduce the same temporal change of the light emission intensity by other means, and the effect of preventing forgery is enhanced. In addition, it is easy to specify the device that has issued and printed the securities.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 shows a printing apparatus according to this embodiment. The printing device prints securities such as the above-described checks. In the figure, a sheet fed from a sheet feeding device is fed onto a belt unit. Then, the belt unit sequentially passes below a group of electrophotographic toner image forming mechanisms including a developing device, an exposing device, and a charging and cleaning device including an image forming carrier. At this time, the electrophotographic toner image is transferred to form a multiplex image.

There are four electrophotographic toner image forming mechanisms. The components of these four units are the same except for the toner loaded in the developing device. As shown in FIG. 1, the toner loaded in these developing devices is color (C) at the first position and fluorescent A (F) at the second position from the upstream side of the paper path.
A), fluorescence B (FB) at the third position, black (K) at the fourth position
It has become. Here, the color (C) at the first position is an arbitrary chromatic toner. Further, the fluorescent A toner at the second position is a toner containing the fluorescent substance A. Similarly, the fluorescent B toner at the third position is a toner containing the fluorescent substance B.

The multiplex image formed on the transfer paper is heated, melted and fixed by a fixing device and fixed on the transfer paper.
As a result, a color image using the fluorescent toner is obtained. Here, in the present embodiment, a color material for producing a fluorescent toner will be described. Coloring materials include inorganic pigments and organic dyes. Inorganic pigments have good stability over time, but have a problem in kneading particles with toner. On the other hand, organic dyes are easy to knead, but are inferior in stability over time of fluorescent color development. In this example, the characteristic of the organic dye, which is inferior in stability over time of the fluorescent color, is used for security.

For this reason, the fluorescent substance used in this embodiment is, for example, an organic dye (organic fluorescent substance) such as a naphthalimide-based or perylene-based dye. The fluorescent A toner and the fluorescent B toner described below are also produced using these organic dyes. In the following description, FIG. 2 shows the spectral emission intensity (curve A) measured by irradiating an ultraviolet ray on an image of a printed matter obtained by printing the fluorescent A toner. FIG. 3 shows fluorescence B
The spectral luminescence intensity (curve B) measured by irradiating an image of a printed matter obtained by printing a toner with ultraviolet light is shown. In FIG.
Both curve A in FIG. 2 and curve B in FIG. 3 are shown.

The fluorescent A toner is composed of 92 parts by weight of a polyester resin as a binder resin, 4.5 parts by weight of a fluorescent agent A which is colorless under visible light and has an emission intensity of visible light reduced by ultraviolet irradiation with the passage of time, blue pigment Pigment Blue The mixture containing 15: 30.5 parts, a charge controlling agent (CCA: white) 1 part by weight, and a release agent polyethylene wax 2 parts by weight was melt-kneaded by a roll mill, cooled, coarsely ground by a hammer mill, and then air After finely pulverizing with a jet pulverizer and classifying into a powder having a particle size of 7 to 12 μm, 1.4 wt% of hydrophobic silica having a particle size of 40 nm and a particle size of 6 with respect to the powder weight.
0.3% of a hydrophobic silica having a thickness of 0.3 nm was adhered with a Henschel mixer to obtain a light blue toner for non-magnetic one component.

A curve A in FIG. 2 shows an image obtained by mounting the thus-obtained fluorescent A toner on the printing apparatus shown in FIG. 1 and printing the solid image with a spectral fluorescence photometer and measuring the spectral emission intensity. The fluorescent A toner is a toner that emits in the visible light wavelength region on the short wavelength side with a strong peak near 430 nm and a weak peak near 520 nm when irradiated with 365 nm ultraviolet light. The excitation ultraviolet wavelength for irradiation is 365
nm fixed. It is not necessary to pay attention to the peak represented by the overscale at the left end of FIG. 2 because it is the irradiation wavelength peak.

When this was visually observed under visible light, an image close to pale blue solid printing was recognized. Irradiation with ultraviolet light (black light; emission center: 365 nm) was performed to recognize the output solid image, and it was confirmed that the emitted light was bluish white with high brightness. Furthermore, the solid image output using this phosphor is used as an input image,
When the image was copied with a commercially available electrophotographic copying machine, a slight halftone image was recognized in the output image.

The curve A 'in FIG. 2 is obtained by measuring the spectral emission intensity after leaving the printed matter printed with the fluorescent A toner for 600 weeks. Since the emission intensity of the fluorescent agent used in the fluorescent A toner decreases with time, the spectral emission intensity of the obtained printed matter is weaker than the initial point of the curve A. When this image was irradiated with black light, almost no light emission was visually observed.
When a copy was made with a commercially available electrophotographic copying machine, the obtained copy was the same as before copying.

The fluorescent B toner is composed of 92 parts by weight of a polyester resin as a binder resin, 5 parts by weight of a fluorescent agent B which is green and yellow under visible light, and whose emission intensity of visible light by ultraviolet irradiation hardly changes with time, and a charge control agent (CC).
A: White) The above mixture containing 1 part by weight of a release agent and 2 parts by weight of a polyethylene wax was melt-kneaded by a roll mill, cooled, coarsely ground by a hammer mill, finely ground by an air jet mill, and classified. After forming a powder having a particle size of 7 to 12 μm, hydrophobic silica having a particle size of 40 nm based on the weight of the powder was added.
4% by weight and 0.3% of hydrophobic silica having a particle size of 6 nm were adhered by a Henschel mixer to obtain a non-magnetic one-component yellow-green toner.

A curve B in FIG. 3 shows an image obtained by measuring the spectral emission intensity of a solid printed image using the fluorescent toner B by the printing apparatus shown in FIG. The fluorescent B toner is a toner that emits on the wavelength side in the visible light wavelength region, having a peak near 530 nm when irradiated with 365 nm ultraviolet light. The excitation ultraviolet wavelength for irradiation is 365 nm
It is not necessary to pay attention to the peak that is fixed and represented by the overscale at the left end of FIG. 3 is the peak of the irradiation wavelength.

When this was visually observed under visible light, an image similar to bright green yellow solid printing was recognized. Also,
Irradiation with ultraviolet light (black light; emission center 365 nm) to recognize this output solid image,
It was confirmed that light was emitted in bright yellow and high luminance visually. Further, when a solid image output using the phosphor was copied as an input image by a commercially available electrophotographic copying machine, a halftone image was output.

A curve B 'in FIG. 3 is obtained by measuring the spectral emission intensity after leaving the printed matter printed with the fluorescent B toner for 600 weeks. Since the luminous intensity of the fluorescent agent used in the fluorescent toner B does not decrease so much with the passage of time, the spectral luminous intensity of the obtained printed matter does not change much from that before leaving. When this image was irradiated with black light, the same yellow light emission as before the standing was confirmed visually. When a copy was made with a commercially available electrophotographic copying machine, the obtained copy was the same as before copying.

FIG. 5 shows a printed matter obtained with the fluorescent A toner,
The change in emission intensity at each emission peak wavelength (fluorescence A: 430 nm, fluorescence B: 530 nm) of a printed matter (excitation ultraviolet wavelength fixed at 365 nm) obtained with the fluorescent B toner is shown by standing time. . When printing is performed on the same paper, the intensity of the fluorescent light A exceeds the intensity of the fluorescent light B immediately after printing, but the intensity reverses after 200 weeks, and the intensity of the fluorescent light B exceeds the intensity of the fluorescent light A.

In the visual observation by irradiation with black light, immediately after printing, the blue-white emission of the fluorescent light A feels brighter than the bright yellow light emission of the fluorescent light B. When irradiated, the light emission exceeds the blue-white light emission of the fluorescent light A. Therefore, a printed matter was created using the printing apparatus shown in FIG. "I" in the figure
Was printed black at the edges and fluorescent A toner at the center. Also,
In FIG. 2B, the edge is printed in color and the center is printed with fluorescent B toner.

The created printed matter was used as an original, and an original left for 300 weeks was prepared. This was compared with a printed matter (hereinafter referred to as a counterfeit) created using a fluorescent toner kit. Both are indistinguishable by ordinary visual judgment under the light of the outdoors and indoors.
That is, in both cases, “A” is drawn in light blue letters with black borders, and “B” is drawn in yellow letters with color borders.

A portion printed with a fake fluorescent A toner,
When the emission peak wavelength of the portion printed with the fluorescent B toner was measured, the intensity of the fluorescent light A exceeded the intensity of the fluorescent light B, and identification was possible. That is, the original could be distinguished from the counterfeit. When the original and the forgery were irradiated with black light, the forgery emitted a bluish white character for the character drawn with "a" and a light yellow for the character drawn with "b". On the other hand, in the original, only the character drawn in "b" emitted light yellow. Therefore, the difference between the two could be determined.

Also, a product (referred to as a second counterfeit product) was prepared in which the amount of the printing toner of the fluorescent A toner was adjusted to be small so that the intensity of the blue-white color became the same as that of the original. In the second counterfeit, the pale blue color of the fluorescent A toner was hardly recognized under normal room light. For this reason, the difference between the original and the second counterfeit could also be determined.

As a method of using the security system according to the present embodiment, a method is conceivable in which an original is produced at the same time as issuing a ticket and stored in a bank or the like in combination with the MICR toner. Then, when confirming the light emission intensity of the fluorescent toner by irradiating ultraviolet rays, the fluorescence toner is compared with the original.

As described above, in this embodiment, forgery and copying can be performed by adding an element that changes with time to image information of fluorescence emission that can be easily distinguished without using a special substance for authenticity determination. A more difficult printed matter can be provided. Further, in the present embodiment, the use of a plurality of fluorescent substances having different degrees of change in the fluorescence emission with time is more complicated. For this reason, it is possible to provide a printed material that is more difficult to forge and copy. <Second Embodiment> This embodiment is a modified example of the first embodiment. The purpose is to prevent forgery of a printed matter such as a check by giving a characteristic to a toner used for printing, as in the first embodiment. In the following description, only differences from the first embodiment will be described.

As shown in FIG. 1, in the printing apparatus shown in FIG. 1, toner (C1) is located at the first position and color (C1) is located at the second position from the upstream side of the paper path as shown in FIG.
2) Fluorescence (F) at the third position and black (K) at the fourth position. Here, the colors (C1 and C2) at the first and second positions are arbitrary chromatic toners. The fluorescent F toner at the third position is a toner containing the fluorescent substances A and B in a one-to-one ratio.

The fluorescent toner F is composed of 92 parts by weight of a polyester resin as a binder resin, 5 parts by weight of a fluorescent agent A, which is colorless under visible light, and whose visible light emission intensity decreases with irradiation of ultraviolet light with the lapse of time, and under visible light. 5 parts by weight of a fluorescent agent B, which is greenish-yellow, and whose visible light emission intensity by ultraviolet irradiation hardly changes with time, and a charge control agent (CCA:
The above mixture containing 1 part by weight of a white color and 2 parts by weight of a release agent polyethylene wax was melt-kneaded by a roll mill, cooled, coarsely ground by a hammer mill, finely ground by an air jet mill, classified, and classified. After making into 7-12 μm granules,
1.4% by weight of 40 nm hydrophobic silica and 0.3% of hydrophobic silica having a particle size of 6 nm were adhered to the powder by a Henschel mixer to obtain a yellow-green non-magnetic one-component toner.

A curve F in FIG. 7 shows an image obtained by mounting the obtained toner on the printing apparatus shown in FIG. 1 and performing solid printing, and measuring the spectral emission intensity with a spectral fluorometer. This curve is
This is obtained by superimposing (adding) the curve A of FIG. 2 and the curve B of FIG. The fluorescent F toner is a toner having peaks near 430 nm and 530 nm due to irradiation of 365 nm ultraviolet rays. This toner emits light on the short wavelength side in the visible light wavelength region. The excitation ultraviolet wavelength to be irradiated is fixed at 365 nm, and the peak shown on the overscale in FIG. 7 represents the peak of this irradiation wavelength. Therefore, there is no need to pay attention.

When this was visually observed under visible light, an image was recognized as a solid green-yellow yellow print. Irradiation with ultraviolet light (black light; emission center: 365 nm) was performed to recognize the output solid printed image. As a result, it was confirmed that light was emitted in a bright blue-green color with high luminance. Further, when a solid image output using the phosphor was copied as an input image by a commercially available electrophotographic copying machine, a halftone image was output.

FIG. 8 shows the change in the luminescence intensity at the luminescence peak wavelength (430 nm, 530 nm) of the printed matter obtained with the fluorescent toner F (the excitation ultraviolet wavelength is fixed at 365 nm). In the figure, A is 430 nm
And B correspond to the peak at 530 nm. When printed on the same paper, the emission intensity at 430 nm immediately exceeds the emission intensity at 530 nm immediately after printing.
The emission intensity at 530 nm is reversed to 430 nm after 0 weeks.
Than the emission intensity of Visually with black light irradiation, it feels bright immediately after printing because the blue-white emission is strong,
The color gradually becomes yellowish.

Therefore, a printed matter was prepared with the pattern shown in FIG. 9 using the printing apparatus of this embodiment. The edge of the character drawn by "C" in the figure is black printing, and the center is fluorescent F toner printing. The printed matter prepared as an original was left for 300 weeks, and a printed matter prepared using a new toner kit (hereinafter referred to as a counterfeit) was compared.

In both cases, under outdoor or indoor light, “C” is drawn in green-yellow characters with black borders, and cannot be distinguished by ordinary visual judgment. When the emission peak wavelength of the image printed as the original is measured, the emission intensity at 530 nm exceeds the emission intensity at 430 nm. On the other hand, when the emission peak wavelength of the image printed as a forgery was measured,
Since the emission intensity at 0 nm exceeded the emission intensity at 530 nm, it was possible to distinguish the original from the counterfeit.

When the original and the counterfeit were irradiated with black light, the characters drawn with "c" emitted yellow light in the case of the counterfeit. On the other hand, in the original, the character drawn with "c" emitted blue-white light. From this, the difference between the two could be determined. As described above, in the present embodiment, the same effects as those of the first embodiment can be realized with one developing device using one developer.

[0036]

As described above, according to the present invention, an element which changes with time is added to image information of fluorescent light which can be easily distinguished without using a special substance for judging authenticity. Thus, a printed material that is more difficult to forge and copy can be provided.

Further, according to the present invention, the use of a plurality of fluorescent materials having different degrees of change of the fluorescence emission with time is more complicated. For this reason, it is possible to provide a printed material that is more difficult to forge and copy.

[Brief description of the drawings]

FIG. 1 is a side view of a printing apparatus according to first and second embodiments.

FIG. 2 is a diagram showing a measurement result of a spectral emission intensity of a fluorescent A toner by irradiation of an ultraviolet ray of 365 nm in the first embodiment.

FIG. 3 is a diagram showing a measurement result of a spectral emission intensity of a fluorescent B toner by irradiation of 365 nm ultraviolet rays in the first embodiment.

FIG. 4 is a diagram in which a curve A of FIG. 2 and a curve B of FIG. 3 are drawn together;

FIG. 5 is a diagram illustrating the light emission intensity at each light emission peak wavelength of a printed matter obtained with the fluorescent toners A and B in the first embodiment with respect to a leaving time.

FIG. 6 is a printing example according to the first embodiment.

FIG. 7 is a diagram illustrating a measurement result of a spectral emission intensity of a fluorescent F (= A + B) toner by irradiation of 365 nm ultraviolet rays in the second embodiment.

FIG. 8 shows the emission peak wavelength (A is 430 n) of a printed matter obtained with the fluorescent toner F in the second embodiment.
(m, B correspond to the emission peak at 530 nm).

FIG. 9 is a printing example according to the second embodiment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/04 G03G 21/00 550 3E041 // G07D 7/12 9/08 361 F term (reference) 2C005 HA01 HA30 HB10 JB14 LA28 2H005 AA21 CA21 2H030 AB02 AD01 BB02 BB21 BB43 2H077 AC04 BA10 EA00 GA00 GA01 GA13 2H134 NA12 NA26 NA27 NA32 3E041 AA01 BA09 BB04 BB05 CA05 DB01

Claims (4)

[Claims] 1. A printing apparatus comprising a plurality of developing devices, each of which includes a toner containing a fluorescent substance that emits in the visible light region different from each other at the same irradiation wavelength in the ultraviolet region. At least one of the fluorescent toners has a property that the light emission intensity changes with time, and is combined so that the degree of change in the light emission intensity of the fluorescent toner in the plurality of developing devices with time varies. A printing device characterized by the above-mentioned. 2. A toner containing two or more fluorescent substances which emit light in the same visible wavelength and different visible light ranges, wherein at least one of the fluorescent substances has a property that the emission intensity changes with time. And toners that are combined so that the degree of change with time of the emission intensity of each fluorescent substance is different. 3. A printing apparatus comprising one developing device, wherein the toner according to claim 2 is mounted on the developing device. 4. A printing apparatus comprising a plurality of developing devices, wherein at least one of the plurality of developing devices has the toner according to claim 2 mounted thereon.