JP2813329B2 - Varnish for detection mark on OHP sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a laser beam printer in which an image is formed on a toner receiving layer by laminating a toner receiving layer on at least one surface of a substrate. OHP sheet
In the OHP sheet, the position of the OHP sheet can be detected when the sheet is conveyed by the image forming apparatus, and the OHP sheet is configured to be transparent by heat when passing through the heat fixing unit roll of the image forming apparatus and form a detection mark that does not become an obstruction during OHP projection. And a varnish for a detection mark.

[0002]

2. Description of the Related Art In recent years, in various fields such as lectures, classes, and briefing sessions, OHP has been used as an information transmission means that appeals to the visual sense.
(Abbreviation for overhead projector, hereafter OH
P) is widely used. Conventional O
As HP sheets, transparent polyester films or polypropylene films were used, and characters and figures were directly hand-written with oil-based ink pens. The image recorded on the OHP sheet is copied on an OHP sheet using an electrophotographic copying machine, or printed directly on the OHP sheet by a laser beam printer capable of outputting data of a personal computer. As described above, an image forming apparatus such as an electrophotographic copying machine or a laser beam printer (hereinafter, may be simply referred to as an image forming machine) is used to
Forming an image on an HP sheet is very convenient in that it is easy to add and modify, and other materials can be used for a manuscript, etc., and is consistent with general needs. However, some of the image forming machines detect the position of a sheet being conveyed in the machine, and there is a problem that an OHP sheet having high transparency is hardly detected. OHP
When an image is formed on a sheet, a toner receiving process is performed so that an image from an image forming machine can be formed on the surface of the OHP sheet. There is no doubt that it must be set on the machine, but it is difficult to distinguish between front and back because of its high transparency.

[0003] In order to solve the above-mentioned problems, a method of printing characters, symbols, and arrows on an OHP sheet using a conventional mark called “aluminum paste ink” or “ink containing titanium oxide” has been proposed. Was formed. However, when the OHP sheet on which the detection mark is formed is projected by the OHP, even the detection mark is projected, so that there is a problem that it is very unsightly and obstructive.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of detection marks during OHP projection, and has been made in view of the above. It is an object of the present invention to provide a varnish for a detection mark in an OHP sheet which can be formed transparent so as to form a detection mark which does not cause an obstruction at the time of OHP projection.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, a toner receiving layer is laminated on at least one surface of a substrate, and the toner receiving layer is formed on an image forming machine. For an OHP sheet on which an image is formed, the varnish having excellent concealing properties before passing through a heat fixing unit roll of an image forming machine and capable of forming a detection mark which is made transparent by heat when passing through the heat fixing unit roll. As
A hollow plastic pigment having a shell part composed of a styrene-acrylic resin forming a hiding agent and having a Tg of 35 ° C to 50 ° C;
A water-based polyester resin and / or a water-based acrylic resin having a binder and having a Tg of 30 ° C to 60 ° C is mixed with 95: 5 to 65:35.
The present inventors have found that the above-mentioned problems can be solved if they are mixed at the solid content ratio of the present invention, and completed the present invention.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a varnish for a detection mark in an OHP sheet according to the present invention will be described in detail with reference to the drawings. 1 to 3 show OHPs according to the present invention, respectively.
FIG. 3 is a cross-sectional view illustrating an example of an OHP sheet on which a detection mark is formed by a detection mark varnish on the sheet.

In the drawings, reference numeral 1 denotes a transparent OHP sheet on which an image is formed by an image forming machine such as an electrophotographic copying machine or a laser beam printer. A back surface layer 5 is laminated on the back surface in consideration of transportability in the image forming machine as shown in FIG.
In addition, as shown in FIG. 3, the toner receiving layer 3 is laminated so that images can be formed on both the front and back surfaces. Reference numeral 4 denotes a detection mark which is made transparent by heat when passing through the heat fixing unit roll of the image forming apparatus. The detection mark 4 is on at least one side of the OHP sheet 1 and, as shown in FIGS. The back layer 5 and the toner receiving layer 3 are laminated on the receiving layer 3, the back substrate 2, and the back layer 5 and the toner receiving layer 3, which are laminated as necessary, or on the substrate 2. In the case of substrate 2
And the back layer 5 and the toner receiving layer 3.
Needless to say, the base material 2, the toner receiving layer 3, the detection mark 4, and the back surface layer 5 laminated as necessary are all transparent members because they are components of the OHP sheet 1 having transparency. No.

Since the substrate 2 is an OHP sheet 1 for an electrophotographic copying machine or a laser beam printer, a polyethylene terephthalate film or a polyethylene terephthalate film is used in consideration of the amount of heat generated by the heat fixing roller of these image forming machines. Suitable for thicknesses from 50 μm to 188
μm is preferred.

As the toner receiving layer 3, toner receptivity,
There is no particular limitation as long as the fixability and storage stability after acceptance are taken into consideration, and polyester resins and acrylic resins are generally used. In order to improve coating properties, a surfactant such as a leveling agent and a wetting agent may be used in combination, or various pigments may be added to the resin to such an extent that transparency is not impaired. The toner receiving layer 3 may be formed by a known coating method, such as a gravure coat, a bar coat, and a blade coat.

The back layer 5 is designed to prevent dust and dirt from adhering due to static electricity in the machine of the image forming machine and to prevent running defects caused by a high friction coefficient. It is not particularly limited as long as it is the same. Generally, the resin is composed of an antistatic agent, a lubricant, and organic and / or inorganic particles.

The detection mark 4 is formed of a detection mark varnish in the OHP sheet according to the present invention.
This detection mark varnish has a function of making it transparent by the heat of the heat fixing unit roll of the image forming machine, and includes a hollow plastic pigment made of styrene-acryl resin serving as a hiding agent, and an aqueous polyester resin serving as a binder. And / or a mixture with an aqueous acrylic resin.

The hollow plastic pigment constituting the former concealing agent remains white at room temperature and exhibits a white color, and when heated and pressurized, the shell of the hollow plastic pigment is melted and broken to become transparent. If the Tg of the shell portion is lower than 35 ° C., the shell portion is melted due to an environmental change during storage and becomes transparent before use, making it impossible to obtain the necessary hiding property. Since a high temperature is required for melting and breaking, it is necessary to increase the temperature in the heat fixing unit roll of the image forming machine or extremely slow the speed of passing the paper through the image forming machine. The Tg of the shell portion is optimally in the range of 35 ° C. to 50 ° C., since the deformation of the shell itself is caused or it is uneconomical.

A water-based polyester resin and / or a water-based acrylic resin forming the latter binder binds the hollow plastic pigments together and forms the base material 2 on which the detection mark 4 is formed, the toner receiving layer 3 or, if necessary, the lamination. When the Tg is less than 30 ° C., the concealing property of the detection mark 4 is not reduced under high temperature conditions (40 ° C. for 30 days) assuming summer. If the Tg exceeds 60 ° C., sufficient transparency of the detection mark 4 cannot be obtained after passing through the heat fixing unit roll of the image forming machine. Therefore, the Tg is optimally in the range of 30 ° C. to 60 ° C. .

The hollow plastic pigment constituting the concealing agent and the aqueous polyester resin constituting the binder and / or
Alternatively, the solid content ratio of the aqueous acrylic resin is 95: 5 to 5: 5 in consideration of the coating strength, adhesion and hiding of the detection mark 4.
OHP sheet 1 according to the present invention mixed in a ratio of 65:35
The varnish for the detection mark in the above is constituted.

[0015]

EXAMPLES The present invention will be described in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto. Parts and% shown in Examples and Comparative Examples mean parts by weight and% by weight, respectively. As the base material 2, a commercially available polyethylene terephthalate film having a thickness of 100 μm (trade name: Tetron HSL type, manufactured by Teijin Limited)
Is coated on the surface of the substrate 2 with a gravure coater so that the applied amount of the solid content after drying is 2.5 g / m ^2. A layer 3 is formed, and a backside coating solution having the following composition is applied to the backside of the base material 2 by a gravure coater so that the solid content after drying is 0.5 g / m ^2. Back layer 5
Is formed on the back surface layer 5 as shown in FIG.
The detection mark varnish of the comparative example was applied by a gravure coater so that the thickness after drying became 5 μm to form the detection mark 4, and the OHP sheet 1 was formed.

<Toner receiving coating liquid> Polyester resin 20 parts (trade name Byron 220, manufactured by Toyobo Co., Ltd.) Surfactant 2 parts (trade name Siastat SN, manufactured by American Cyanamide Co.) Inorganic pigment (silica) 1 part (Product name: Sylysia 770, manufactured by Fuji Silysia K.K.) Toluene 40 parts MEK 37 parts

<Backside coating liquid> Polyester resin 20 parts (trade name Byron 200, manufactured by Toyobo Co., Ltd.) Surfactant 2 parts (trade name Siastat SN, manufactured by American Cyanamide Co.) Inorganic pigment (silica) 1 part ( Product name Sylysia 730, manufactured by Fuji Silysia Limited) Toluene 40 parts MEK 37 parts

EXAMPLE 1 Concealing agent for hollow plastic pigment (trade name: Grosdale 250-S, manufactured by Mitsui Toatsu Chemicals Co., Ltd.) made of styrene-acrylic resin having a solid content of 50% and a Tg of 40 ° C. , And 24 parts of a binder of a water-soluble polyester resin (trade name: Pluscoat Z446, manufactured by Ryo Kagaku Co., Ltd.) having a solid content of 25% and a Tg of 45 ° C. A varnish for a detection mark having a binder and a solid content ratio of 85:15 was obtained.

Example 2 A concealing agent for a hollow plastic pigment made of styrene-acrylic resin (trade name: Grosdale 250-S, manufactured by Mitsui Toatsu Chemicals, Inc.) having a solid content of 50% and a Tg of 40 ° C. was used. 68 parts and a binder of a water-soluble acrylic resin (trade name: Joncryl J52, manufactured by Johnson Polymer Co., Ltd.) having a solid concentration of 60% and a Tg of 57 ° C. are mixed, and a concealing agent and a binder are mixed. And a varnish for a detection mark having a solid content ratio of 89:11 were obtained.

Comparative Example 1 A non-hollow plastic pigment (polysol OLY-6491, trade name, manufactured by Showa Polymer Co., Ltd.) made of styrene-acrylic resin having a solid content of 50% and a Tg of 40 ° C. was 68. Parts and a binder of 24 parts of a water-soluble polyester resin (trade name: Pluscoat Z446, manufactured by Ryo Kagaku Co., Ltd.) having a solid concentration of 25% and a Tg of 45 ° C., and the concealing agent and the binder are mixed. A varnish for a detection mark composed of a solid content ratio of 85:15 was obtained.

Comparative Example 2 An opaque agent of a hollow plastic pigment (trade name: Grosdale 1494SX, manufactured by Mitsui Toatsu Chemicals, Inc.) made of styrene-acrylic resin having a solid content of 50% and a Tg of 30 ° C. was used.
68 parts and 24 parts of a binder of a water-soluble polyester resin (trade name: Plus Coat Z446, manufactured by TAIYO CHEMICAL CO., LTD.) Having a solid concentration of 25% and a Tg of 45 ° C. are mixed, and the concealing agent and the binder are mixed. Was obtained as a detection mark varnish having a solid content ratio of 85:15.

Comparative Example 3 Hollow plastic pigment made of styrene-acrylic resin having a solid content of 30% and a Tg of 105 ° C. (trade name)
Nipol MH5055, manufactured by Nippon Zeon Co., Ltd.)
And a water-soluble polyester resin with a solid content of 25% and a Tg of 45 ° C (trade name Pluscoat Z446,
And 24 parts of a binder (manufactured by Co., Ltd.) to obtain a varnish for a detection mark in which the concealing agent and the binder had a solid content ratio of 85:15.

Comparative Example 4 A concealing agent for hollow plastic pigment (trade name: Grosdale 250-S, manufactured by Mitsui Toatsu Chemicals, Inc.) composed of styrene-acrylic resin having a solid content of 50% and a Tg of 40 ° C. 68 parts and 24 parts of a binder of a water-soluble polyester resin (trade name: Plus Coat Z850, manufactured by Ryo Kagaku Co., Ltd.) having a solid concentration of 25% and a Tg of 20 ° C. are mixed, and the concealing agent and the binder are mixed. Was obtained as a detection mark varnish having a solid content ratio of 85:15.

With respect to the OHP sheet prepared as described above, the concealing property is determined by measuring the portion where the detection mark is formed by using a transmission densitometer.
The Macbeth TR-924 visual filter (hereinafter simply referred to as a transmission densitometer) measures the measured value to determine the density of the detection mark area. The concealing property and the decoloring property after passing through an image forming machine are manufactured by Canon Inc. The detection mark after copying a white original with the PIXEL CLC-500 (after passing through the heat fixing unit roll) is measured by the transmission densitometer, and the measured value is used as the detection mark part density. Table 1 shows the storability of the detection mark portion after storage for 30 days in an environment of 40 ° C. using the transmission densitometer. The overall evaluation in Table 1 is
The concealability and storability can be clearly identified by the detection mark.
As described above, the color erasability is defined as a standard value of 0.07 or less, at which the detection mark does not cause an obstruction at the time of OHP projection, and is evaluated as good when all of the standard values are satisfied.

The evaluation of the detection marks formed by the detection mark varnishes of the above Examples and Comparative Examples is as shown in Table 1. In Examples 1 and 2, the necessary concealing property was obtained before passing through the heat fixing unit roll, and after passing through the heat fixing unit roll, transparency (decoloring property) that would not obstruct the OHP projection.
Was obtained, and the storage stability was also good. Comparative Example 1
With regard to the decoloring property, the transparency after passing through the heat fixing unit roll was not sufficient. In Comparative Example 2, the necessary hiding property before passing through the heat fixing unit roll was not obtained in preservability. In Comparative Example 3, since the Tg of the shell portion of the concealing agent was high in decoloring properties, the transparency after passing through the heat fixing unit roll was not sufficient.
In Comparative Example 4, the necessary hiding property before passing through the heat fixing unit roll was not obtained in the preservability.

[0026]

[Table 1]

[0027]

As described in detail above, the OHP according to the present invention is
The varnish for the detection mark on the sheet enables the front and back of the OHP sheet to be distinguished when an image is formed on the surface of the OHP sheet by an image forming machine such as an electrophotographic copying machine or a laser beam printer, and at the time of image formation. The OHP sheet position can be detected at the time of conveyance, and furthermore, a detection mark which is transparent by heat when passing through the heat fixing unit roll of the image forming machine and which can be erased to the extent that it does not obstruct the OHP projection can be formed. It is of great value.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an OHP sheet on which a detection mark is formed by a detection mark varnish in the OHP sheet according to the present invention.

FIG. 2 is a cross-sectional view showing one example of an OHP sheet on which a detection mark is formed by a detection mark varnish in the OHP sheet according to the present invention.

FIG. 3 is a cross-sectional view illustrating an example of an OHP sheet on which a detection mark is formed by a detection mark varnish in the OHP sheet according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 OHP sheet 2 Base material 3 Toner receiving layer 4 Detection mark 5 Back surface layer

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 7/00 G03G 7/00 B

Claims (1)

(57) [Claims] A toner receiving layer (3) is formed by laminating a toner receiving layer (3) on at least one surface of a substrate (2) by an image forming machine such as an electrophotographic copying machine or a laser beam printer.
A varnish for a detection mark which constitutes a detection mark (4) which is made transparent by heat when passing through a heat fixing unit roll of the image forming machine in an OHP sheet (1) on which an image is formed, and comprises a concealing agent. A hollow plastic pigment having a shell portion made of styrene-acrylic resin and having a Tg of 35 ° C to 50 ° C;
A water-based polyester resin and / or a water-based acrylic resin having a binder Tg of 30 ° C to 60 ° C is 95: 5 to 65:35.
OHP characterized by being mixed at a solid content ratio of
Varnish for detection mark on sheet.