JP2000080597A - Paper for machine reading, and method and apparatus for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper for machine reading, having a material suitable for the machine reading, and imparted to the region from the surface of the paper to the desired inside part with an enough fastness, and further to provide a production method and a production apparatus thereof. SOLUTION: This paper for machine reading is obtained by imparting a material suitable for the machine reading to the region from the surface of the paper to the desired inside part so as to form a belt shape or an arbitrary shape by controlling the distance of the surface of a wet paper and a spray nozzle 6, and the pressure by which the material suitable for the machine reading is sprayed, when a spraying apparatus having the spray nozzle 6 is installed and the material suitable for the machine reading is sprayed from the nozzle 6 toward the surface of the paper layer on the papermaking machine by using the spray apparatus in the process for forming a paper layer in a papermaking machine. The production method and the production apparatus are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine-readable sheet, a method for manufacturing the same, and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art As a countermeasure for preventing forgery of various security papers, a method of applying a material suitable for machine reading, such as a fluorescent material, on the paper surface or in a paper layer has been attempted.

Here, as a method of applying a material suitable for machine reading to the surface of a sheet, there are generally applied by printing and by coating with a coater.

In a method in which a material suitable for machine reading is mixed with a varnish or a pigment to form an ink and printed by various printing methods such as flexographic printing and offset printing, the material is usually provided in a state having a design as a part of a character or design. Is done. Using the various printing methods described above, when trying to apply a material suitable for machine reading to the paper surface in a state invisible to the naked eye, the printed portion on the paper and the non-printing due to the varnish component in the ink A clear gloss difference occurs in the part, and it is difficult to apply the gloss in a state invisible to the naked eye.

[0005] In a method of mixing a material suitable for machine reading with a binder to form a coating liquid and coating with a coater, a method of coating the entire surface of a paper is known. And JP-A-8-49198.

As a method of applying pigments and the like to the paper surface at the stage of paper production, as described in JP-T-10-500901, a large amount of low-speed atomizing spray mist is applied to the entire surface of the paper with the pigment. There is a way to do that. The purpose of this coating method is to atomize the coating substance by air pressure and spray it onto the entire surface of the paper at a low pressure, and the coating substance is applied to the entire surface of the paper.

On the other hand, as a method of applying a material suitable for machine reading over the entire surface of the paper layer of the paper, the material is mixed in paper stock to form a paper, and the material suitable for machine reading is dispersed throughout the paper. A method of applying the composition is known.

Further, as a method of partially applying a material suitable for machine reading to the inside of a paper layer, Japanese Patent Publication No. 6-63200
No. 2, there is a method in which a fibrous material is partially mixed in a round tank of a round paper machine.

[0009]

Among the conventional techniques, a method of printing a material suitable for machine reading by various printing methods such as flexographic printing and offset printing, and a method of coating using a coater, require that the material be coated on paper. It requires a processing step such as printing or coating to give the surface.

When a material suitable for machine reading by printing is applied to a sheet in a state having a design, it is necessary to consider the design so as to be suitable for identification of the material.
In order to make the presence of the material invisible to the naked eye, it was necessary to hide the material by printing design, and in any case, the design had to be restricted.

A method in which a material suitable for machine reading is coated on the entire surface of the paper using a coater as disclosed in Japanese Patent Application Laid-Open No. Hei 10-500901, and a large amount of low-speed atomization spray mist as disclosed in JP-A-8-49198. In the method of coating the entire surface of the paper surface in the state described above, since the material cannot be partially applied, processing for partially concealing the paper surface is required to detect the presence or absence of the material. .

In addition, the method of applying the material to the entire surface of the paper, including the method of mixing the material suitable for machine reading into the stock and making the paper, and dispersing and applying the material to the entire paper, involves the use of the expensive material. It is not economically acceptable as a method of providing.

Further, as in Japanese Patent Publication No. 6-63200,
In the method of partially mixing the fibrous material in the round tank of the round paper machine, the shape of the material is restricted, and even if the same method is tried on the fourdrinier, the paper layer is disturbed. Can not be adopted because it will.

Therefore, in the present invention, a material suitable for machine reading is distributed to an arbitrary portion of the paper surface and even to a region reaching the inside of the paper layer, and applied in an invisible state which cannot be visually recognized by the naked eye. It is an object of the present invention to obtain a machine-readable sheet having a high anti-counterfeiting effect, an economical manufacturing method thereof, and an apparatus for manufacturing the same.

[0015]

In order to achieve the above object, according to the present invention, in the process of forming a paper layer of a paper machine, a material suitable for machine reading is continuously or intermittently applied to an arbitrary portion of the surface of a wet paper. By spraying, the material is applied to a desired area up to the surface of the paper and the inside of the paper layer with sufficient rigidity, so that the process can be simplified and the amount of the material used can be reduced.

That is, in the machine-readable paper of the present invention, a spray device having a spray nozzle is installed in the process of forming the paper layer of the paper machine, and the paper machine is used by using the spray device. In spraying the material suitable for machine reading toward the surface of the wet paper above, by controlling the distance between the surface of the wet paper and the nozzle and the pressure for spraying the material suitable for machine reading, the surface of the paper is controlled. It is characterized in that a material suitable for machine reading is applied to a region up to a desired inside.

Further, the machine-readable paper of the present invention is provided in claim 2 of the present invention.
As described above, any one of an ultraviolet absorbing material, an infrared absorbing material, and a fluorescent material is used as a material suitable for machine reading.

Further, the machine-readable paper of the present invention is characterized in that:
As described above, by using a material of the same or similar color to the paper as the material suitable for machine reading, the material suitable for machine reading given to the paper is made invisible in a normal state. And

Further, the machine-readable paper of the present invention is provided in claim 4.
As described, on the downstream side of the slice that regulates the flow rate when the stock flows out on the plow mesh, at the site where the moisture of the wet paper until it enters the dandy roll is being initially dewatered by the plow mesh, A material suitable for machine reading is sprayed toward the surface.

Further, the machine-readable paper of the present invention is characterized in that:
As described, at the downstream side of the dandy roll for smoothing the wet paper web surface, a material suitable for machine reading was sprayed toward the surface of the wet paper web at the site where the dewatering is being forcibly dewatered by suction of the suction box. Features.

Further, the machine-readable paper of the present invention is provided in claim 6.
As described above, a material suitable for machine reading is continuously applied in a belt shape.

Further, the machine-readable paper of the present invention is provided in claim 7.
As described, a material suitable for machine reading is provided intermittently and intermittently.

In the method for producing a machine-readable paper according to the present invention, a spray device having a spray nozzle is installed in the process of forming the paper layer of the paper machine, and the spray device is used. When spraying a material suitable for machine reading toward the surface of the wet paper on the paper machine, the distance between the surface of the wet paper and the nozzle and the pressure for spraying the material suitable for machine reading are controlled. A material suitable for machine reading is applied to a region from the surface to the desired interior.

In the method for manufacturing a machine-readable sheet according to the present invention, any one of an ultraviolet absorbing material, an infrared absorbing material, and a fluorescent material is used as a material suitable for machine reading. It is characterized by doing.

According to a tenth aspect of the present invention, there is provided a method for manufacturing a machine-readable sheet, wherein a material having the same or similar color as the sheet is used as a material suitable for machine reading. A material suitable for machine reading is made invisible in a normal state.

According to the present invention, there is provided a method for producing a machine-readable sheet according to claim 11, wherein the step of adjusting the flow rate when the stock flows out on the plow mesh is performed on the downstream side of the slice until the stock enters the dandy roll. A material suitable for machine reading is sprayed onto the surface of the wet paper at a portion where the moisture of the wet paper is being initially dehydrated by the crossing net.

According to a twelfth aspect of the present invention, there is provided a method for manufacturing a machine-readable sheet in a portion downstream of a dandy roll for smoothing the surface of a wet paper web, which is being forcibly dewatered by suction of a suction box. And spraying a material suitable for machine reading toward the surface of the wet paper.

According to a thirteenth aspect of the present invention, there is provided a method of manufacturing a machine-readable sheet, by continuously spraying a material suitable for machine-reading on an arbitrary portion of the wet paper to thereby advance the wet-paper. In addition, a material suitable for machine reading is provided in a strip shape.

Further, according to the method of manufacturing a machine-readable sheet according to the present invention, the wet paper is moved in an advancing direction by intermittently spraying a material suitable for machine reading onto an arbitrary portion of the wet paper. In addition, a material suitable for machine reading is provided intermittently.

According to a fifteenth aspect of the present invention, in the machine for forming a machine-readable sheet, a spray device having a spray nozzle is installed in a process of forming a paper layer of a paper machine, and the spray device is used. When spraying a material suitable for machine reading toward the surface of the wet paper on the paper machine, the distance between the surface of the wet paper and the nozzle and the pressure for spraying the material suitable for machine reading are controlled. A material suitable for machine reading is applied to a region from the surface to the desired interior.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION In order to achieve the above object, the present invention is suitable for machine reading using a spray device having a spray nozzle for wet paper in the process of forming a paper layer on a paper machine. The sprayed material is continuously or intermittently sprayed from the nozzle. By adjusting the spray position on the paper machine, the distance between the surface of the wet paper and the nozzle, the shape of the nozzle, the spray pressure, the spray time, and the spray interval, the amount and position of the material suitable for machine reading,
Controls the shape and distribution in the paper layer.

[0032]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

That is, in the embodiment described below, an example is shown in which titanium dioxide, which is one of ultraviolet absorbing materials, is used as a material suitable for machine reading, but other ultraviolet absorbing materials include, for example, zinc sulfide. And inorganic substances such as zinc cadmium sulfide and calcium sulfide, and organic substances such as imidazole, diaminodiphenyl and thiazole, and these substances can also be used.

Further, in the same manner as in the embodiment described below, an infrared absorbing material such as an indium-based compound, a zirconium-based compound, an anthraquinone-based compound or the like can be used as a material suitable for machine reading.

Further, as a material suitable for machine reading, a fluorescent light emitting material which emits a wavelength in any one of a visible region, an ultraviolet region, and an infrared region can be used. Materials emitting light in the visible region include, for example, zinc sulfide-based compounds, zinc oxide-based compounds, zinc silicate-based compounds, and the like.
Materials emitting light in the ultraviolet region include, for example, BaSi2O
5 :: Pb, SrB4O7: Eu, Ca3 (PO4) 2: Tl, etc. Materials emitting light in the infrared region include, for example, LiAlO2: Fe, (Z
n · Cd) S: Cu, YVO4: Nd and the like.

Further, although the following examples are based on a fourdrinier paper machine, a short net paper machine and a round net paper machine can be used by using the same method at the initial dewatering of the stock. Similar effects can be obtained.

(Embodiment 1) FIG. 1 is a schematic view showing an embodiment of the present invention. In FIG. 1, (1) is a plow net,
(2) is a slice, (3) is a suction box,
(4) is a dandy roll, (5) is a press roll,
(6) is a spray nozzle for spraying a material suitable for machine reading, (7) is a pump for sending out the material, (8) is a circulation pipe for circulating the material, and (9) is a time and interval for spraying the material. (10) is a control panel that controls the solenoid valve, (11) is a tank of the material, (1)
2) is a stirrer for stirring the above-mentioned materials, and (13) is a wet paper web in which a stock obtained by adding clay and internal chemicals to softwood bleached kraft pulp is being dewatered on the plow net (1). The composition of the material (14) suitable for machine reading is a mixture of 0.5 parts of titanium dioxide with respect to water and 0.1 parts of sodium hexametaphosphate with respect to titanium dioxide. It can be changed appropriately according to the output level required to detect a material suitable for reading. Instead of titanium dioxide, any of the above-mentioned materials suitable for machine reading may be used.

The material in a tank (11) of material suitable for machine reading is pumped out by a pump (7) for feeding out the material, and the material is passed through a circulation pipe (8) through which the material is circulated. Is sprayed on a wet paper web (13) on a sieving net by a spray nozzle (6). Since the spray nozzle (6) for spraying the material can move freely on the plow net, spraying can be performed at an arbitrary position on the plow net (1). The unsprayed material passes through a circulation pipe (8) for circulating the material,
Returning to the material tank (11) again prevents settling into the circulation pipe (8). A stirrer (12) for stirring the material prevents the material from settling into the material tank (11). The amount of the material sprayed from the spray nozzle (6), the shape applied to the wet paper web (13),
The distribution inside the wet paper web (13) depends on the type of spray nozzle (6) that sprays the material, the distance between the spray nozzle (6) that sprays the material and the wet paper web (13), and the pump ( 7) The solenoid valve (9) for adjusting the pressure, the time and interval of spraying the material, and the control panel (10) for controlling the solenoid valve are freely controlled.

FIG. 2 shows a spray nozzle (6) for spraying a material suitable for machine reading of FIG. 1 at the site where the moisture of the wet paper web is being initially dehydrated through a grate, in this embodiment a slice (2). Is installed at a position of 50 mm on the downstream side such that the distance between the surface of the wet paper web and the spray nozzle is 60 mm,
The material (14) was sprayed continuously at a pressure of 0.25 Kgf / cm 2, and a material portion (16) suitable for machine reading, which is not actually visible to the naked eye, of the formed paper (P1) is shown. FIG. Sprayed titanium dioxide (16) is applied to paper (P
It is applied in the form of a strip without disturbing the paper layer of 1), and can be confirmed by the ultraviolet monitor but not visible to the naked eye. FIG.
(A) is a backscattered electron image (17) of the section (16) of the sheet (P1) of FIG. FIG. 3B illustrates the distribution state (18) of titanium dioxide in FIG. 3A by X-ray fluorescence analysis. From FIGS. 3A and 3B, it can be confirmed that titanium dioxide is applied to the center of the paper layer. The advantage of applying at the site of this embodiment is that the machine reading function can be kept robust by being applied at a deeper part of the paper layer.

FIG. 4 is a diagram showing the spectral reflection amount at an ultraviolet wavelength of 365 nm between the sheets A and B in FIG. In FIG. 4, the waveform (16 ') corresponding to (16) in FIG. 2, which is a portion sprayed with a material suitable for machine reading, is a waveform (16') in the portion (15) not sprayed with the material in FIG. Since the amount of reflection is lower than that of 15 ′), it is possible to determine whether the difference is true or false by judging the presence or absence of the difference and the size. An advantage of the material being applied in a belt shape is that the material is applied to any part in the flow direction at the time of paper manufacture, so that the material which is invisible to the naked eye can be easily detected. .

(Embodiment 2) FIG. 5 shows a spray nozzle (6) for spraying a material suitable for machine reading as shown in FIG.
Is placed at a position 50 mm downstream of the dandy roll (4) in this example, so that the distance between the surface of the wet paper web and the nozzle is 50 mm. A material portion suitable for machine reading that is invisible to the naked eye and actually printed on paper (P2) that has been intermittently sprayed at a pressure of 3 kgf / cm2 and spraying time of 0.01 second (2)
It is the figure which assumed and showed (0), (21), and (22). The sprayed material (20), (21), (22) is paper (P2)
Are intermittently provided in an elliptical shape without disturbing the paper layer of the above, and can be confirmed by the ultraviolet monitor but cannot be visually recognized by the naked eye. The advantage of applying at the site in this embodiment is that the originally intended shape can be imparted without changing the imparted shape due to the dehydration action. FIG. 6 (a)
5 is a backscattered electron image (23) of a cross section between A and B of the portion (20) where the material is sprayed on the sheet (P2) of FIG. FIG. 6B illustrates the distribution state (24) of titanium dioxide in FIG. 6A by X-ray fluorescence analysis. From FIGS. 6A and 6B, it can be confirmed that titanium dioxide is provided near and inside the surface of the paper layer.

FIG. 7 is a view showing the spectral reflection amount at an ultraviolet wavelength of 365 nm between the sheets A and B in FIG. In FIG. 7, waveforms corresponding to (20), (21), and (22) in FIG.
0 ′), (21 ′) and (22 ′) have a lower reflection amount than the waveform (19 ′) of the portion (19) where the material is not sprayed in FIG. By judging the size or the like, the authenticity can be determined. The advantage of providing the material intermittently is that the amount of expensive material used can be reduced, and the accuracy of authenticity determination can be increased by specifying a portion to which the material is applied. .

When printing on the sheets (P1) and (P2) shown in FIGS. 2 and 5, since the material suitable for machine reading is provided in a state invisible to the naked eye, the printed matter can be freely designed. it can.

(Embodiment 3) FIG. 8 shows a portion (20) of a sheet (P2) in FIG.
Using a friction tester type II (Gakushin type) specified in L0849, a 200 g weight was applied to a friction element having a silk cloth attached to the tip, and an ultraviolet wavelength 365 n before and after rubbing 500 times.
FIG. 6 is a diagram showing the spectral reflection amount of m. When comparing the waveform before rubbing in FIG. 8A with the waveform after rubbing in FIG. 8B, there is almost no difference in output intensity. This indicates that the material is provided with sufficient rigidity.

(Comparative Example) FIG. 9 shows a spray nozzle (6) for spraying a material (14) suitable for machine reading in FIG. 1 after a wet paper web is dehydrated to about 60 to 70%. In this comparative example, the material (14) was installed at a position 50 mm downstream of the press roll (5) so that the distance between the surface of the wet paper web and the nozzle was 50 mm, and the material (14) was sprayed with a pressure of 3 kgf / cm 2 and a spray time of 0.1 mm. Paper made by intermittent spraying in 01 seconds (P ')
It is.

FIG. 10A is a backscattered electron image (26) of a cross section between A and B of a portion (25) of the sheet (P ') of FIG. 9 where a material suitable for machine reading is sprayed. FIG. 10 (b)
Is the distribution of titanium dioxide in Fig. 10 (a) (27)
Is shown by X-ray fluorescence analysis. From FIGS. 10A and 10B, it can be confirmed that titanium dioxide is applied only to the surface of the paper layer.

Even when a general paper (not shown) provided with a material suitable for machine reading by printing is observed using the above-described analysis method, the distribution state of the material is shown in FIG.
And (b), and the material was confirmed only on the surface of the paper layer.

Further, in a general paper (not shown) provided with a material suitable for machine reading by printing, since the material is provided on the surface of the paper layer together with the binder, it was produced in Example 1 described above. Compared to the paper (P1) of FIG. 2 or the paper (P2) of FIG. 5 prepared in Example 2, the invisible effect when the above material was seen with the naked eye was inferior.

FIG. 11 shows a portion (25) sprayed with a material suitable for machine reading of the paper of FIG. 9 using a friction tester type II (Gakushin type) specified in JISL 0849, and using a silk cloth at the tip. It is the figure which showed the amount of spectral reflection of 365 nm of ultraviolet wavelengths before and after 200 g of weight was applied to the attached friction element and rubbed 500 times. Compared to the waveform before friction in FIG. 11A, the waveform after friction in FIG. 11B has a lower output intensity. From this, it can be seen that since the material was present only on the surface of the paper layer, sufficient fastness to friction was not obtained.

As described above, in order to obtain sufficient robustness when a material suitable for machine reading exists only on the surface of the paper layer, it is necessary to add a binder to the material. When added, the invisible effect when viewed with the naked eye was inferior to when not added.

[0051]

According to the present invention, materials suitable for machine reading are:
Since it is applied to the inside of the paper layer, it is entangled with the fibers of the paper, has sufficient robustness to withstand practical use without using a binder, and does not easily fall off from the paper once it has become a product. In addition, by controlling the spraying position, time, pressure, etc., the material is sufficiently robust to the inside of the paper layer at any part of the product paper surface without disturbing the paper layer at the papermaking stage. Since it is provided with the property, the process can be simplified and the amount of the material used can be reduced as compared with the related art. At this time, when the material is applied in a state invisible to the naked eye, there is no need to consider design in printing.

Further, by detecting a material suitable for machine reading inside the paper layer, it is possible to effectively determine the authenticity of a forged product in which the material is applied only to the surface using a method such as printing. be able to.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a spray device for spraying a material suitable for machine reading on a paper machine.

FIG. 2 is a diagram showing a sheet on which a material suitable for machine reading is applied in a belt shape by a spray device during initial dehydration on the downstream side of a slice.

FIG. 3 is a cross-sectional view taken along a line AB of a portion of the sheet of FIG. 2 to which titanium dioxide is applied.

FIG. 4 is a waveform diagram of the ultraviolet spectral reflection amount between A and B of the sheet of FIG. 2;

FIG. 5 is a diagram showing a sheet to which a material suitable for machine reading is intermittently applied by a spray device during forced dewatering on a suction box.

FIG. 6 is a cross-sectional view taken along a line AB of a portion of the sheet of FIG. 5 to which titanium dioxide is applied.

FIG. 7 is a waveform diagram of an ultraviolet spectral reflection amount between A and B of the sheet of FIG. 5;

FIG. 8 is a waveform diagram of an ultraviolet spectral reflection amount before and after rubbing the sheet of FIG. 5;

FIG. 9 is a diagram showing a sheet on which a material suitable for machine reading is intermittently applied by a spray device on a downstream side of a press roll in which water is dehydrated to about 60 to 70%.

10 is a cross-sectional view taken along a line AB of a portion of the sheet of FIG. 9 to which titanium dioxide is applied.

FIG. 11 is a waveform diagram of the ultraviolet spectral reflection amount before and after rubbing the sheet of FIG. 9;

[Explanation of symbols]

(1) Pour net of Fourdrinier (2) Slice (3) Suction box (4) Dundee roll (5) Press roll (6) Spray nozzle for spraying material suitable for machine reading (7) Sending out the material Pump (8) Circulation pipe for circulating the material (9) Solenoid valve for adjusting the time and interval of spraying the material (10) Control panel for controlling the solenoid valve of (9) (11) Tank for the material (12) ) Stirrer to stir the above material (13) Wet paper in grate of (1) (14) Material suitable for machine reading (15) Part where the above material is not applied (15 ') (15) Ultraviolet ray Waveform of spectral reflection amount (16) Waveform of ultraviolet spectral reflection amount of part (16 ') (16) provided with the material (17) Reflected electron image of cross section of paper provided with the material (18) Paper layer Titanium dioxide present inside (19) (19 ') (19) Waveform of ultraviolet spectral reflection amount of the portion to which no material is applied (20) (20) Waveform of ultraviolet spectral reflection amount of the portion to which the material is applied (20') (20) (21) The material (21 ') Waveform of UV spectral reflection amount of (21) (21) Waveform of UV spectral reflection amount of portion (22') (22) provided with material (23) (24) Titanium dioxide present inside the paper layer (25) Part to which the material is applied (26) Backscattered electron image of the cross section of paper to which the material is applied (27) Paper Titanium dioxide present on the layer surface (P1) Paper sprayed with the above material at the site where wet paper is being initially dehydrated (P2) Paper sprayed with the above material at the site where wet paper is being forcibly dewatered (P ') Wet Paper sprayed with the material after the paper is dehydrated to about 60 to 70%

Continuation of the front page (72) Inventor Hiromi Uchimura 6-50-50-406 Sakanori, Odawara-shi, Kanagawa Prefecture (72) Inventor Futami Nishi 3-41-10-1 Koenji Minami 3-chome, Suginami-ku, Tokyo F-term (reference) 4L055 AG04 AG09 AG19 AG39 AH50 BD03 BD11 BE08 CE90 FA21 GA45

Claims (15)

[Claims] In the process of forming a paper layer of a paper machine,
When a spray device having a spray nozzle is installed and a material suitable for machine reading is sprayed toward the surface of the wet paper on the paper machine using the spray device, the distance between the surface of the wet paper and the nozzle, the mechanical reading A machine-readable sheet characterized in that a material suitable for machine reading is applied to a region from the surface of the sheet to a desired interior by controlling a pressure at which the material is sprayed. 2. The machine-readable paper according to claim 1, wherein any one of an ultraviolet absorbing material, an infrared absorbing material, and a fluorescent material is used as the material suitable for machine reading. 3. The method according to claim 1, wherein the material suitable for machine reading is the same color or similar color as the paper, so that the material suitable for machine reading given to the paper is made invisible in a normal state. The machine-readable sheet according to claim 1 or 2, wherein: 4. At a site downstream of the slice for adjusting the flow rate when the stock material flows out onto the plow mesh, at a site where the moisture of the wet paper until it enters the dandy roll is being initially dewatered by the plow mesh, The machine-readable paper according to any one of claims 1 to 3, wherein a material suitable for machine-reading is sprayed toward the surface. 5. At a downstream side of the dandy roll for smoothing the surface of the wet paper web, a material suitable for machine reading is sprayed toward the surface of the wet paper web at a site where forced suction is performed by suction of the suction box. The machine-readable sheet according to any one of claims 1 to 3, wherein: 6. The machine-readable sheet according to claim 1, wherein a material suitable for machine-reading is continuously applied in a belt shape. 7. The machine-readable sheet according to claim 1, wherein a material suitable for machine-reading is intermittently applied. 8. The process of forming a paper layer of a paper machine,
When a spray device having a spray nozzle is installed and a material suitable for machine reading is sprayed toward the surface of the wet paper on the paper machine using the spray device, the distance between the surface of the wet paper and the nozzle, the mechanical reading A method for producing a machine-readable sheet, characterized in that a material suitable for machine reading is applied to a region from the surface of the sheet to a desired inside by controlling a pressure for spraying the material suitable for the sheet. 9. The method according to claim 8, wherein any one of an ultraviolet absorbing material, an infrared absorbing material, and a fluorescent material is used as the material suitable for machine reading. 10. A method according to claim 1, wherein the material suitable for machine reading is a material having the same or similar color as the paper, so that the material suitable for machine reading applied to the paper is made invisible in a normal state. The method for manufacturing a machine-readable sheet according to claim 8 or 9, wherein 11. At a site downstream of the slice for adjusting the flow rate when the stock flows out onto the plow mesh, at a portion where the moisture of the wet paper until it enters the dandy roll is being initially dehydrated by the plow mesh, A material suitable for machine reading is sprayed toward the surface.
0. A method for producing a machine-readable sheet according to any one of the above items. 12. Spraying a material suitable for machine reading onto the surface of the wet paper web at a site downstream of the dandy roll for smoothing the surface of the wet paper web and being forcibly dewatered by suction of the suction box. The method for producing a machine-readable sheet according to any one of claims 8 to 10, wherein: 13. A material suitable for machine reading is applied in a strip shape in the traveling direction of the wet paper by continuously spraying a material suitable for machine reading onto an arbitrary portion of the wet paper. The method for producing a machine-readable sheet according to claim 11 or 12. 14. A material suitable for machine reading is intermittently applied in a traveling direction of the wet paper by intermittently spraying a material suitable for machine reading to an arbitrary portion of the wet paper. The method for producing a machine-readable sheet according to claim 11 or 12. 15. In a process of forming a paper layer of a paper machine, a spray device having a spray nozzle is installed, and a material suitable for machine reading is directed toward the surface of a wet paper web on the paper machine using the spray device. In spraying, by controlling the distance between the surface of the wet paper web and the nozzle and the pressure at which the material suitable for machine reading is sprayed, the material suitable for machine reading can be applied to the area from the surface of the paper to the desired interior. An apparatus for manufacturing machine-readable paper, characterized in that: