JP2007017719A - Fluorescent toner, printing system and printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fluorescent toner capable of printing a full-color fluorescent image which produces luminescence, upon irradiation with ultraviolet light, a printing system which allows simple printing of small-lot full-color fluorescent images, and a printing machine therefor. <P>SOLUTION: As a red fluorescent material, Y2 O2 S:Eu (material prepared by doping Y2 O2 S with europium) is used, as a green fluorescent material, BaMg2 Al16O27:Eu,Mn (material prepared by doping BaMg2 Al16O27 with europium and manganese) is used, and as a blue fluorescent material, BaMg2 Al16O27:Eu is used. Each of the fluorescent materials is kneaded with a polyester resin for toner, a polyethylene-based wax and a charge imparting material, and the kneaded material is pulverized and classified to produce red, green and blue fluorescent toners. These three kinds of color fluorescent toners are housed in image forming units 5-1 to 5-3 of a general-purpose electrophotographic printing machine 1, and printing is performed with the RGB fluorescent toner according to RGB image information, wherein black toner is used only for letters or is not used at all. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluorescent toner, a printing method using the fluorescent toner, and a printing machine that performs the printing.

Conventionally, various proposals relating to printed matter that emits fluorescence have been made. For example, there is a proposal for a full-color fluorescent print, and an offset printing method is used as the printing method. (For example, refer to Patent Document 1.)
As another printing method, a full-color fluorescent printing method using a thermal transfer method has been proposed. (For example, see Patent Documents 2 to 4.)
In addition, a printing method using a fluorescent toner containing a fluorescent material that emits visible light when irradiated with ultraviolet light has been proposed. (For example, see Patent Documents 5 to 8.)
JP-A-10-250212 JP 2003-001935 A JP 2000-158823 A JP 07-125403 A JP 2003-107803 A JP 2002-003855 A JP 05-281786 A Special table 2003-533741 gazette

  By the way, although the technique of patent document 1 employ | adopts the offset printing method as a printing method, although offset printing is an effective method when printing a printed matter in large quantities, it is one in order to print a small number of copies. Since the price per copy is high, it is not a suitable printing method for creating printed materials in general offices and homes.

  In addition, the techniques of Patent Documents 2 to 4 can be said to be a method suitable for printing a small variety of products as compared with the technique of Patent Document 1 because the printing apparatus is small and easy to handle.

  However, in general, the standard for estimating the cost of printing is a printing rate of 5%, in other words, the printing rate of ink on paper is 5% in terms of area. That is, in the fluorescent printing by the thermal transfer method, only 5% of the fluorescent ink on the thermal transfer sheet (thermal transfer ink ribbon) is used.

  In the thermal transfer type, a thermal transfer sheet that has been used once must be discarded, and therefore 95% of unused fluorescent material remaining on the used thermal transfer sheet is discarded. Fluorescent materials are generally expensive, and the thermal transfer method results in high printing costs.

  In addition, the techniques of Patent Documents 5 to 8 do not particularly specify the color to be emitted, that is, the emission wavelength, and basically only describe a method of performing electrophotographic printing using one type of fluorescent toner. Absent.

  These fluorescent printing methods print using special fluorescent toners other than normal printing colors magenta, cyan, yellow, and black, and the images printed with the fluorescent toner are colorless and difficult to see, but are irradiated with ultraviolet rays. By doing so, it has a function of emitting light and confirming it visually.

  However, since these use only a single color fluorescent toner, it is possible to distinguish whether light is emitted or not, but there is a significant limitation on the formation of images by fluorescence. It is impossible to form

  In view of the above-described conventional situation, the problem of the present invention is a fluorescent toner capable of emitting a full-color visible light image by irradiation of ultraviolet rays, a printing method capable of easily printing a small-lot fluorescent full-color image using the fluorescent toner, and It is to provide a printing machine that performs printing.

  The fluorescent toner of the first invention is usually colorless and is configured to emit red light when irradiated with ultraviolet rays. The maximum emission wavelength of the light emitted in red is, for example, 580 to 800 nm.

  This fluorescent toner contains, for example, “Y 2 O 2 S: Eu” (a material in which europium is doped in Y 2 O 2 S) as a material that emits red light.

  The fluorescent toner of the second invention is usually colorless and is configured to emit green light when irradiated with ultraviolet rays. The maximum emission wavelength of the light emitted in green is, for example, 490 to 570 nm.

  This fluorescent toner contains, for example, “BaMg 2 Al 16 O 27: Eu, Mn” (a material in which europium and manganese are doped in BaMg 2 Al 16 O 27) as a material emitting green light.

  The fluorescent toner of the third invention is normally colorless and is configured to emit blue light when irradiated with ultraviolet rays. The maximum emission wavelength of the blue light is, for example, 380 to 490 nm.

  This fluorescent toner contains, for example, “BaMg 2 Al 16 O 27: Eu” (a material in which europium is doped in BaMg 2 Al 16 O 27) as a material that emits blue light.

  The electrophotographic printing system according to the fourth aspect of the invention is a method for printing a full-color fluorescent light emitting image using at least three kinds of fluorescent toners that are usually colorless and emit light in red, green, and blue when irradiated with ultraviolet rays. Configured to do.

  The electrophotographic printing system according to the fifth aspect of the present invention is usually loaded with at least four types of toners that are colorless and emit red, green, and blue light when irradiated with ultraviolet rays, and at least four types of visible color toners. In the electrophotographic printing method in which printing is performed by an electrophotographic printing machine, the visible color toner can be set so as not to be used for an arbitrary printing position.

  The printing system according to the sixth aspect of the invention uses a developer that is usually colorless and emits green, red, and blue light when irradiated with ultraviolet rays, and produces a full-color fluorescent image by irradiation with ultraviolet rays. In the printing method for printing the printed matter that emits light, the developer having the weakest emission intensity is developed on the side closest to the ultraviolet irradiation side of the printed matter.

  This printing method is, for example, configured to perform printing on the printed matter by an electrophotographic printing method using a fluorescent toner that is usually colorless as the developer and emits visible light when irradiated with ultraviolet rays. The

  The electrophotographic printer according to the seventh aspect of the invention prints a full-color fluorescent emission image using at least three types of fluorescent toners that are normally colorless and emit light in red, green, and blue, respectively, when irradiated with ultraviolet rays. Configured to do.

  The electrophotographic printer according to the eighth aspect of the invention is normally loaded with at least four types of toners that are colorless and emit red, green, and blue light when irradiated with ultraviolet rays, and at least four types of visible color toners. In an electrophotographic printer that performs printing, the visible color toner can be set so as not to be used for an arbitrary printing location.

  The printing machine according to the ninth aspect of the invention uses a developer that is normally colorless and emits green, red, and blue light when irradiated with ultraviolet rays, and produces a full-color fluorescence image by irradiation with ultraviolet rays. In a printing machine that prints printed matter that emits light, the developer having the weakest emission intensity is developed on the side closest to the ultraviolet irradiation side of the printed matter.

  For example, this printing machine is configured to print the printed matter by an electrophotographic printing method using a fluorescent toner that is usually colorless as the developer and emits visible light when irradiated with ultraviolet rays. The

  According to the present invention, there are provided a fluorescent toner capable of emitting a full-color visible light image by irradiation of ultraviolet rays, a printing method capable of easily printing a small-lot fluorescent full-color image using the fluorescent toner, and a printing machine for performing the printing. It becomes possible to do.

  Embodiments of the present invention will be described below with reference to the drawings. The prescriptions of the respective fluorescent toners described below are determined in advance after considering the performance of the printing press used for printing.

(Embodiment 1)
First, as Embodiment 1, a method for producing a fluorescent toner that is normally colorless and emits red light when irradiated with ultraviolet rays will be described.

1. 86% by mass of polyester resin for toner having a softening point of 134 ° C
2. Fluorescent material (particles of Y2 02 S doped with europium, average particle size is 1.22 μm in number average, measured with FPIA-2100 manufactured by Sysmex) 10% by mass
3. 3% by mass of polyethylene-based WAX (“NP056” manufactured by Mitsui Chemicals)
4). 1% by mass of charge imparting material (Organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.)
After mixing the above four types of materials with a mixer, kneading was performed while applying temperature (maximum temperature 160 ° C.) with a twin screw kneader.

  The obtained kneaded material was pulverized to about 2 mm with a mechanical pulverizer, then further pulverized to a small particle size with an airflow pulverizer, and classified to a target particle size.

  Thereafter, silica particles surface-treated with silicon oil or alkyldisilazane (2% by mass with respect to the kneaded pulverized product) were externally added to the kneaded pulverized product, and passed through a sieve to obtain a toner.

  The softening temperature of this toner is 133 ° C., and the average particle diameter is 9.4 μm in volume average (D50).

(Embodiment 2)
Next, as Embodiment 2, a method for producing a fluorescent toner that is usually colorless and emits green light when irradiated with ultraviolet rays will be described.

1. 86% by mass of polyester resin for toner having a softening point of 134 ° C
2. Fluorescent material (particles of BaMg2 Al16027 doped with europium and manganese, average particle size is 0.96 μm in number average, measured with FPIA-2100 manufactured by Sysmex) 10% by mass
3. 3% by mass of polyethylene-based WAX (“NP056” manufactured by Mitsui Chemicals)
4). 1% by mass of a charge imparting material (Organic boron compound “LR-147” manufactured by Nihon-Litt)
After mixing the above four types of materials with a mixer, kneading was performed while applying temperature (maximum temperature 160 ° C.) with a twin screw kneader.

  The obtained kneaded material was pulverized to about 2 mm with a mechanical pulverizer, then further pulverized to a small particle size with an airflow pulverizer, and classified to a target particle size.

  Thereafter, silica particles surface-treated with silicon oil or alkyldisilazane (2% by mass with respect to the kneaded pulverized product) were externally added to the kneaded pulverized product, and passed through a sieve to obtain a toner.

  The softening temperature of this toner is 133 ° C., and the average particle diameter is 9.2 μm in volume average (D50).

(Embodiment 3)
Furthermore, as Embodiment 3, a method for producing a fluorescent toner that is normally colorless and emits blue light when irradiated with ultraviolet rays will be described.

1. 86% by mass of polyester resin for toner having a softening point of 134 ° C
2. Fluorescent material (particles doped with europium in BaMg2Al16O27, average particle diameter is 1.00 μm in number average, measured with FPIA-2100 manufactured by Sysmex) 10% by mass
3. 3% by mass of polyethylene-based WAX (“NP056” manufactured by Mitsui Chemicals)
4). 1% by mass of charge imparting material (Organic boron compound “LR-147” manufactured by Nippon Carlit Co., Ltd.)
After mixing the above four types of materials with a mixer, kneading was performed while applying temperature (maximum temperature 160 ° C.) with a twin screw kneader.

  The obtained kneaded material was pulverized to about 2 mm with a mechanical pulverizer, then further pulverized to a small particle size with an airflow pulverizer, and classified to a target particle size.

  Thereafter, silica particles surface-treated with silicon oil or alkyldisilazane (2% by mass with respect to the kneaded pulverized product) were externally added to the kneaded pulverized product, and passed through a sieve to obtain a toner.

  The toner has a softening temperature of 134 ° C. and an average particle diameter of 8.8 μm in volume average (D50).

  In the first to third embodiments, an inorganic fluorescent material is used, but an organic fluorescent material may be used instead of an inorganic fluorescent material.

That is, materials other than Y2O2S: Eu (a material in which Y2O2S is doped with europium) may be used as the red fluorescent inorganic fluorescent material. For example, “Y 2 O 3: Eu”, “(Y, Gd) BO 3: Eu)”, “Y (P, V) O 4: Eu”, “YVO 4: Eu”,
“ZnS: Mn”, “(Sr · Mg) 3 (PO 4) 2: Sn”, “(ZnSr) 3 (PO 4) 2: Mn”, “3.5MgO · 0.5MgF 2 · GeO 2: Mn”, “Mg 5 As2O11: Mn "," (Ca, Sr) Si03: Pb, Mn "or the like can be used.

  Further, as the inorganic fluorescent material emitting green light, a material other than BaMg2Al16O27: Eu.Mn (a material in which BaMg2Al16O27 is doped with europium and manganese) may be used. For example, “Zn 2 SiO 4: Mn”, “(Ba, Sr, Mg) O · aA 12 O 3 Mn”, “(Y, Gd) BO 3: Tb”, “ZnO: Zn”, “(Ba, Eu) (Mg, Mn) Al10O17 "," ZnS: CulAl "," ZnS: Cu, Au, Al "," Gd2 O2 S: Tb "," LaPO4: Ce, Tb "," Sr4Al14O25: Eu "," CeMgAl11O19: Tb " “Ce (Mg, Zn) Al 11 O 19: Mn”, “CeMgAl 11 O 19: Ce, Tb” or the like can be used.

  As the inorganic fluorescent material emitting blue light, a material other than BaMg2Al16O27: Eu (a material obtained by doping europium into BaMg2Al16O27) may be used. For example, “BaMgAl10O17: Eu”, “(Sr, Ca, Ba, Mg) 10 (PO4) 6 C12: Eu”, “(Ba, Sr, Eu) (Mg, Mn) Al10O17”, “Sr10 (PO4) 6 C12 : Eu "," (Ba, Eu) MgAl10O17 "," ZnS: Ag "," Y2SiO5: Tb "," ZnS: Ag, Al "," (Sr, Ca, Ba, Mg) 5 (PO4) 3Cl " = Eu "," CaWO4 "," Ba2 SrMg3 Al30O51: Eu, Mn "," CaWO4: Pb "," Sr2 P2 O7: Eu "," (Sr, Ca, Ba) 3 (PO4) 2 C12: Eu ", “3Sr3 (PO4) 2 C12: Eu” or the like can be used.

(Embodiment 4)
Subsequently, as a fourth embodiment, an electrophotographic printing method and an electron which are performed using three types of fluorescent toners that fluoresce the red (R), green (G), and blue (B), which are additive primary colors. A photographic printer will be described.

  First, each of the above three types of fluorescent toner is filled in a toner cartridge, and these toner cartridges are attached to an electrophotographic printer (N5300, manufactured by Casio Computer Co., Ltd.), and printing is performed on general printer paper. It was.

  FIG. 1 is a cross-sectional view illustrating the internal configuration of the above-described electrophotographic printer (hereinafter referred to as an electrophotographic printer).

  As shown in FIG. 1, the electrophotographic printer 1 includes an image forming unit 2, a duplex printing transport unit 3, and a paper feeding unit 4. The image forming unit 2 has a configuration in which four image forming units 5 (5-1, 5-2, 5-3, 5-4) are arranged in a multistage manner.

  Of the four image forming units 5, the three image forming units 5-1, 5-2, and 5-3 on the upstream side in the sheet conveyance direction (right side in the drawing) A mono-color image is formed with toners of the three primary colors magenta (M), cyan (C), and yellow (Y), and the image forming unit 5-4 forms a monochrome image mainly with black (K) toner such as characters. To do.

  Each of the image forming units 5 has the same configuration except for the developer (color) accommodated in the developing container. Therefore, hereinafter, the configuration of the image forming unit 5-3 will be described as an example.

  The image forming unit 5 is assembled to the photosensitive drum 6, a cleaner 7 disposed along the circumferential surface of the photosensitive drum 6, a charger 8, a developing container 9, and an opening on a lower side surface of the developing container 9. The developing roller 11 is provided.

  A print head 12 on the main body side is disposed near the upper surface of the photosensitive drum 6 between the charger 8 and the developing container 9, and a conveyance belt 13 is disposed near the lower surface of the photosensitive drum 6. Has been. The transfer device 14 is pressed toward the lower surface of the photosensitive drum 6 with the conveying belt 13 interposed therebetween.

  The conveyor belt 13 is stretched between the driving roller 15 and the driven roller 16 and driven by the driving roller 15 to circulate in the counterclockwise direction in the figure.

  The photosensitive drum 6 rotates in the clockwise direction in the figure. First, by applying a charge from the charger 8, the peripheral surface of the photosensitive drum 6 is uniformly charged and initialized. Next, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 6 by optical writing from the print head 12 based on the print information.

  The electrostatic latent image is converted into a toner image (development) by the toner stored in the developing container 9 by the developing process by the developing roller 11.

  The toner image developed on the peripheral surface of the photosensitive drum 6 in this way reaches a transfer portion where the photosensitive drum 6 and the transfer device 14 face each other as the photosensitive drum 6 rotates.

  On the other hand, a large number of cut sheets 18 are accommodated in the sheet feeding cassette 17 of the sheet feeding unit 4. The sheet 18 is unloaded from the sheet feeding cassette 17 by one rotation of the sheet feeding roller 19, and is fed to the standby roller pair 22 through the conveyance guide path 21. Alternatively, the paper is fed to the standby roller pair 22 by the paper feed roller 25 from the MPF tray 24 mounted on the opened mounting portion 23.

  The standby roller pair 22 feeds the paper 18 onto the transport belt 13 at a timing when the print start position of the paper 18 coincides with the front end of the toner image on the photosensitive drum 6 of the image forming unit 5-1 at the most upstream in the paper transport direction.

  The sheet 18 is electrostatically attracted to and conveyed by the upper surface of the circulating conveyor belt 13 and moves together with the conveyor belt 13 directly below the photosensitive drum 6 from the upstream side to the downstream side in the sheet conveying direction.

  Then, the first color toner image is transferred to the sheet 18 by the transfer unit of the image forming unit 5-1, and the next color toner image is transferred by the transfer unit of the image forming unit 5-2. The third toner image is transferred by the transfer unit -3, and the black toner image is transferred as necessary by the transfer unit of the image forming unit 5-4.

  The sheet 18 on which the three-color or four-color toner images are transferred in this manner is carried into the fixing unit 26. The fixing unit 26 includes a heat roller 26a, a pressure roller 26b, and a cleaner 26c. While the paper 18 is nipped and conveyed between the heat roller 26a and the pressure roller 26b, the toner image is melted and pressed onto the paper surface. To settle. The cleaner 26c removes the toner remaining on the heat roller 26a.

  As described above, the sheet 18 on which the toner image is fixed by the fixing unit 26 is discharged out of the apparatus with the image forming surface facing upward by the carry-out roller 28 when the switching plate 27 is rotated upward. When the plate 27 is rotated downward, it is guided upward by the conveying roller 29 and is discharged to the paper discharge unit 32 by the paper discharge roller 31 with the image forming surface down.

  Further, the duplex printing transport unit 3 is configured to be detachable from the apparatus main body, and is a unit that is mounted when duplex printing is performed by the electrophotographic printer 1 of the present example. The duplex printing transport unit 3 has a plurality of transport rollers 33a to 33e disposed therein.

  In the case of duplex printing, the sheet 18 is once sent upward by the switching plate 27. For example, when the rear end of the sheet 18 reaches the conveying roller 29, the conveyance of the sheet 18 is stopped and the sheet 18 is moved in the reverse direction. Transport to.

  By this control, the paper 18 is conveyed downward on the left side of the switching plate 27 set at the position indicated by the dotted line, is carried into the paper conveyance path of the duplex printing conveyance unit 3, and the paper is returned by the conveyance rollers 33a to 33e. The

  The returned paper 18 again passes through the conveyance guide path 21 and reaches the standby roller pair 22, and is sent to the transfer unit at the same timing as the toner image as described above, and the toner image is transferred to the back surface of the paper.

  FIG. 2 is a diagram showing an internal circuit configuration in the electrophotographic printer 1 having the above mechanism and configuration. As shown in the figure, the circuit configuration of the electrophotographic printer 1 includes an interface (I / F) 34, a CPU (central processing unit) 35, an EEPROM (electrically erasable programmable ROM) 36, a ROM (read only memory) 37, a print A controller 38, a printer printing unit 39, an operation panel 41, and a sensor unit 42 are included.

  The interface (I / F) 34 inputs red (R), green (G), and blue (B) print data sent from a host device (not shown), and creates respective bitmap data. This bitmap data is stored in the frame memory 43.

  The frame memory 43 includes 43R, 43G, 43B, and 43K corresponding to red (R), green (G), blue (B), and black (K).

  The red (R) bitmap data is stored in the storage area 43R of the frame memory 43, the green (G) bitmap data is stored in the storage area 43G of the frame memory 43, and the blue (B) bitmap data. Is stored in the storage area 43B of the frame memory 43, and black (K) bitmap data is stored in the storage area 43K of the frame memory 43.

  The CPU 35 is a central control unit that performs printing control and system control of the electrophotographic printer 1 of this example, and performs control according to a program stored in the ROM 37. Further, the CPU 35 inputs an operation signal from a key operation unit provided on the operation panel 41, and outputs a display signal to a display unit also provided on the operation panel 41.

  The EEPROM 36 stores various correction values and adjustment values. The ROM 37 stores a print program and a control program.

  The printer controller 38 converts the bitmap data supplied from the interface (I / F) 34 for each of red (R), green (G), blue (B), and black (K) to the red (R), green ( G), blue (B), and black (K) are output to the printer printing unit 39.

  The printer printing unit 39 includes the above-described image forming units 5-1 to 5-4, the print heads 12 corresponding thereto, and the like.

  As the bitmap data output to the printer printing unit 39, for example, red (R) data is supplied to the print head 12 of the image forming unit 5-3, and green (G) data is supplied to the image forming unit 5-2. The blue (B) data is supplied to the print head 12 of the image forming unit 5-1, and the black (K) data is supplied to the print head 12 of the image forming unit 5-4. Is done.

  Thereby, as described above, the blue (B) fluorescent toner image is transferred to the paper 18 as the first color toner image at the transfer portion of the image forming unit 5-1, and the transfer portion of the image forming unit 5-2. Then, the green (G) fluorescent toner image is transferred as the color, the red (R) fluorescent toner image is transferred as the third color at the transfer portion of the image forming unit 5-3, and if necessary, The black toner image is transferred at the transfer portion of the image forming unit 5-4.

  As described above, any of the three types of fluorescent toners R, G, and B can be applied to any location by inputting a desired image signal without performing special settings of the general-purpose machine of the N5300 printer, and with only a slight configuration change. Could also print.

  The printed portion of the fluorescent toner is almost white (colorless), and it is difficult to distinguish it from the plain portion of the paper 18 by visual recognition. When this printed matter (paper 18 on which the fluorescent toner image has been transferred and heat-fixed) is irradiated with ultraviolet rays containing a wavelength of 365 nm with a mercury lamp, the printed portions of the fluorescent toner are red, green, blue, Emitted light.

  Next, printing was performed by combining the above fluorescent toners. When the red fluorescent toner and the green fluorescent toner were overlaid and printed, an image emitting yellow light was obtained.

  Similarly, red and blue fluorescent toners emitted magenta, and green and blue fluorescent toners emitted cyan.

  Further, when three types of fluorescent toners of red, green, and blue were overlaid and printed, an image that emitted white light was obtained.

  That is, by using the three types of R, G, and B fluorescent toners, a full-color fluorescent image could be printed.

  Further, instead of printing three types of toners of R, G, and B on top of each other, even if dot printing is performed side by side, for example, three dots arranged in a triangle are regarded as one pixel, and each of the three dots is red, Even when printing was performed so as to distribute green and blue fluorescent toners, a full-color fluorescent image could be obtained using three types of fluorescent toners that emit light.

  Three types of fluorescent toner and four types of image forming units 5 of black toner were mounted on the electrophotographic printer 1 (N5300), and printing of black toner was attempted along with printing of three types of fluorescent toner.

  As a result, it was possible to print with black toner together with a full-color fluorescent image in the same image. That is, a fluorescent image and a colored black image could be printed without damaging each image.

  The electrophotographic printer 1 (N5300) is equipped with four types of image type units 5 of three types of fluorescent toner and black toner, and in the “do not use black toner” mode (for the image image) mode, When printing was attempted, it appeared white (colorless), but when irradiated with ultraviolet light, a full-color image similar to the original photographic image appeared.

  Similarly, when printing a photographic image in the “use black toner (for image image)” mode, black toner is developed for a part of the black portion of the photographic image. Only the black part was visually recognized in the white (colorless) image.

  In addition, the full-color fluorescent image by ultraviolet irradiation also has a poor color balance especially in the black portion compared to the original photographic image.

  Further, the four types of image forming units 5 of three types of fluorescent toner and black toner are mounted on the electrophotographic printer 1 (N5300), and “(not use the black toner)” and “(text image)”. In the "Use black toner" mode, an attempt was made to print an image in which a photo and black text coexist, but the black portion was not used for the photo portion, and the black text portion was not used. Developed black toner.

  That is, it was possible to perform printing in which a portion using black toner and a portion not using it were specified.

  As described above, according to the present invention, since full-color fluorescent printing is performed by an electrophotographic method, it is possible to easily cope with a small number of copies compared to a general printing method such as offset printing.

  Further, since only the amount of toner corresponding to the printing rate is used, printing with less waste of ink material (toner in this example) can be performed as compared with the thermal transfer printing method.

  As described above, according to the present invention, it is possible to perform a small amount and a variety of printing at a low cost.

  In addition, using a general-purpose printer and printing with three types of red, green, and blue fluorescent toners and black toner, it is possible to simultaneously print colored black toner at specified locations along with the full-color emission image. For example, it is possible to print an almost white (colorless) full-color fluorescent image with an explanatory text in black. This is particularly effective when printing photographic images and the like.

(Embodiment 5)
By the way, as a result of performing various printing using each color fluorescent toner as described above, in the multiple transfer of each color fluorescent toner at the time of printing, there is a difference in the image when irradiated with ultraviolet rays due to the combination of the overlapping transfer order. It turned out to come out.

  This seemed to be due to the difference in the fluorescence intensity of each color toner. In general, it is known that a fluorescent material that emits red light has lower emission intensity than fluorescent materials that emit green or blue light.

  FIG. 3 is a chart that evaluates the fidelity between the combination of the order of transfer of the three color fluorescent toners and the original photographic image of the image when irradiated with ultraviolet rays.

  The chart shows from the first combination to the sixth combination from top to bottom as combinations of the superimposing transfer order of the three color fluorescent toners. From left to right, the combination test number, the toner color of the primary transfer (transferred by the image forming unit 5-1), the toner color of the secondary transfer (transferred by the image forming unit 5-2), and the tertiary transfer (image forming unit) 5-3) and the evaluation of fidelity with the original photographic image.

  As shown in the chart, in the first combination, red fluorescent toner was used for primary transfer, green fluorescent toner was used for secondary transfer, and blue fluorescent toner was used for tertiary transfer. And evaluation was "x".

  In the second combination, red fluorescent toner was used for primary transfer, blue fluorescent toner was used for secondary transfer, and green fluorescent toner was used for tertiary transfer. And evaluation was "x".

  In the third combination, green fluorescent toner was used for primary transfer, red fluorescent toner was used for secondary transfer, and blue fluorescent toner was used for tertiary transfer. And evaluation was "(triangle | delta)".

  In the fourth combination, green fluorescent toner is used for primary transfer, blue fluorescent toner is used for secondary transfer, and red fluorescent toner is used for tertiary transfer. And evaluation was "(circle)".

  In the fifth combination, blue fluorescent toner was used for primary transfer, red fluorescent toner was used for secondary transfer, and green fluorescent toner was used for tertiary transfer. And evaluation was "(triangle | delta)".

  In the final sixth combination, blue fluorescent toner was used for primary transfer, green fluorescent toner was used for secondary transfer, and red fluorescent toner was used for tertiary transfer. And evaluation was "(circle)".

  From the results in the above table, the closer the development position (coating position) of the fluorescent toner emitting red light is to the ultraviolet irradiation side (the farther from the paper, the later the transfer order), the better (evaluation is “◯”). It has been found that a full-color fluorescence image can be obtained.

  The order of transfer of the fluorescent toner emitting green light and the fluorescent toner emitting blue light did not significantly affect the image evaluation.

  As described above, since the fluorescent material emitting red light has lower emission intensity than the fluorescent material emitting green or blue, the amount of red light emitting fluorescent material added is larger than that of green or blue light emitting fluorescent material. It is effective as a measure to reinforce the above weak points of the red light emitting fluorescent material.

  However, on the other hand, this may cause a problem that the balance of toner physical properties between toners is deteriorated. Another concern is that many expensive fluorescent materials must be used.

  In order to alleviate them, the light emission intensity is weak at the position where the irradiated ultraviolet rays are the strongest and the light emission is the most on the surface (the transfer order is the third transfer position in the last three colors) from the chart of FIG. It can be seen that it is effective to develop the red light emitting toner.

  FIG. 4 is a diagram specifically showing the order of development of the fluorescent toners when a full-color fluorescent light emitting image that gives the above-mentioned good evaluation “◯” is printed on plain paper. In the figure, only the image forming unit 2 shown in FIG.

  As shown in FIG. 4, from the upstream side in the paper conveyance direction, the primary transfer unit by the image forming unit 5-1, the secondary transfer unit by the image forming unit 5-2, the tertiary transfer unit by the image forming unit 5-3, and the image A quaternary transfer portion is formed by the forming unit 5-4.

  In the primary transfer portion of the image forming unit 5-1, the fluorescent toner is transferred to the lowest position on the paper surface (the position farthest from the ultraviolet irradiation side). Blue or G (green) fluorescent toner is placed.

  Further, in the secondary transfer portion by the image forming unit 5-2, the fluorescent toner is transferred to the second position on the sheet surface, that is, the position not the top of the three colors. In the case of 2, G (green) or B (blue) fluorescent toner is also arranged.

  Then, in the tertiary transfer unit by the image forming unit 5-3, the fluorescent toner is transferred to the top position on the paper surface among the three colors (the position closest to the ultraviolet irradiation side). In 5-3, R (red) fluorescent toner is always arranged.

  Incidentally, the quaternary transfer portion by the image forming unit 5-4 is a quaternary transfer portion in order, but this image forming unit 5-4 is exclusively for black toner, and as described above, in the case of fluorescent toner printing. Since the image quality deteriorates when the black toner is transferred onto the fluorescent toner, the black toner is not transferred onto the fluorescent toner. That is, when printing a fluorescent image, black toner is used in the description or not at all.

  In the fifth embodiment, a case where a full-color fluorescent image is printed on plain paper is taken as an example. However, a transparent film such as an OHP film is used as a print medium instead of plain paper. When the fluorescent image is observed by irradiating with ultraviolet rays from the opposite side, the order of developing the fluorescent toners printed on the film is preferably reversed from the above. That is, it is preferable to develop the red light emitting fluorescent toner at a position closest to the print medium surface.

  In the above embodiment, the toner image is directly transferred from the image forming units 5-1 to 5-4 onto the paper 18 transported by the transport belt 13, but instead of the transport belt 13. An intermediate transfer belt corresponding to this is provided, and after the images are once transferred from the image forming units 5-1 to 5-4 onto the intermediate transfer belt, the transferred images are collectively transferred onto separately conveyed paper. An intermediate transfer belt method may be used.

  Even in this case, the order of developing the fluorescent toner is reversed. That is, the red light emitting fluorescent toner is first transferred onto the intermediate transfer belt so that the red light emitting fluorescent toner is first on the paper surface when batch-transferred onto the paper. A luminescent fluorescent toner is preferably arranged.

FIG. 3 is a cross-sectional view illustrating an internal configuration of an electrophotographic printer that performs printing by an electrophotographic printing method using the fluorescent toner of the present invention. It is a figure which shows the circuit structure inside an electrophotographic printer. It is the chart which evaluated the fidelity with the combination of the superposition transfer order of three color fluorescent toner, and the original photograph image of the image at the time of ultraviolet irradiation. It is a figure which shows concretely the development order of the fluorescent toner in the case of printing the full-color fluorescence emission image from which favorable evaluation "(circle)" is obtained on plain paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic printer 2 Image formation part 3 Duplex printing conveyance unit 4 Paper feed part 5 (5-1, 5-2, 5-3, 5-4) Image formation unit 6 Photosensitive drum 7 Cleaner 8 Charger 9 Development Container 11 Developing roller 12 Print head 13 Conveyor belt 14 Transfer device 15 Drive roller 16 Driven roller 17 Paper feed cassette 18 Paper 19 Paper feed roller 21 Conveyance guide path 22 Waiting roller pair 23 Mounting portion 24 MPF tray 25 Paper feed roller 26 Fixing unit 26a Heat roller 26b Pressure roller 26c Cleaner 27 Switching plate 28 Unloading roller 29 Conveying roller 31 Discharging roller 32 Discharging unit 33a to 33e Conveying roller 34 Interface (I / F)
35 CPU (central processing unit)
36 EEPROM (electrically erasable programable ROM)
37 ROM (read only memory)
38 Print Controller 39 Printer Printing Unit 41 Operation Panel 42 Sensor Unit 43 Frame Memory

Claims (17)

  A fluorescent toner that is usually colorless and emits red light when irradiated with ultraviolet rays.   The fluorescent toner according to claim 1, wherein the maximum emission wavelength of the red light is 580 to 800 nm.   2. The fluorescent toner according to claim 1, wherein "Y2 O2 S: Eu" (a material in which europium is doped in Y2 O2 S) is contained as the red light emitting material.   A fluorescent toner which is usually colorless and emits green light when irradiated with ultraviolet rays.   The fluorescent toner according to claim 4, wherein the maximum emission wavelength of the light emitted in green is 490 to 570 nm.   5. The fluorescent toner according to claim 4, wherein "BaMg2Al16O27: Eu, Mn" (a material in which BaMg2Al16O27 is doped with europium and manganese) is contained as the green light emitting material.   A fluorescent toner which is usually colorless and emits blue light when irradiated with ultraviolet rays.   The fluorescent toner according to claim 7, wherein the maximum emission wavelength of the blue light is 380 to 490 nm.   8. The fluorescent toner according to claim 7, wherein "BaMg2Al16O27: Eu" (a material obtained by doping europium into BaMg2Al16O27) is contained as the blue light emitting material.   An electrophotographic printing system characterized in that a full-color fluorescent emission image is printed using at least three types of fluorescent toners, which are usually colorless and emit light in red, green, and blue when irradiated with ultraviolet rays. Electrophotography that is printed by an electrophotographic printer loaded with at least four types of toners, which are usually colorless and emit three colors of red, green, and blue, respectively, and visible color toners when irradiated with ultraviolet rays. In the formula printing method,
An electrophotographic printing method characterized in that it can be set so that the visible color toner is not used for an arbitrary printing location. In a printing method that prints a printed matter that emits a full-color fluorescence image by irradiation of ultraviolet rays, using at least three types of developers that are usually colorless and emit green, red, and blue when irradiated with ultraviolet rays. ,
A printing system comprising developing a developer having the weakest emission intensity on the side closest to the ultraviolet irradiation side of the printed matter.   13. The developer according to claim 12, wherein a fluorescent toner that is normally colorless and emits visible light when irradiated with ultraviolet rays is used as the developer, and the printed matter is printed by an electrophotographic printing method. Printing method.   An electrophotographic printer characterized in that it prints a full-color fluorescent emission image using at least three types of fluorescent toners that are normally colorless and emit red, green, and blue light when irradiated with ultraviolet rays. In an electrophotographic printing machine, which is usually colorless and is loaded with at least four types of toners, ie, three types of toners that emit red, green, and blue light when irradiated with ultraviolet rays, and visible color toners.
An electrophotographic printing machine characterized in that it can be set so that the visible color toner is not used for an arbitrary printing place. In a printing press that prints a printed matter that emits a full-color fluorescence image by irradiation of ultraviolet rays, using at least three types of developers that are usually colorless and emit green, red, and blue light when irradiated with ultraviolet rays. ,
A printing machine for developing a developer having the weakest emission intensity on the side closest to the ultraviolet irradiation side of the printed matter. 17. The developer according to claim 16, wherein a fluorescent toner that is normally colorless and emits visible light when irradiated with ultraviolet rays is used as the developer, and the printed matter is printed by an electrophotographic printing method. Printer.

Images