JPH04125567A - Light transparent transfer medium - Google Patents

Abstract

PURPOSE:To embed a color toner into a toner image holding layer contg. a thermoplastic resin having the softening point lower than the softening point of the toner and to enhance the transmittance of the toner image by forming the above-mentioned holding layer on the surface of a transparent base material. CONSTITUTION:This medium is formed with the toner image holding layer 12 on the surface of the transparent base material 11. This layer 12 consists of the thermoplastic resin and is required to have the softening point lower than the softening point of the toner. This thermoplastic resin is also required to have light transparency after fixing of the toner image 13, to well adhere to the base material 11 and to have the practicably usable surface hardness. An acrylonitrile/styrene copolymer, etc., are usable for the above-mentioned layer and polyethylene terephthalate, etc., are usable for the base material 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a transfer medium for creating translucent color images.

(Prior Art) In order to create a translucent color image in electrophotography, it is common to fix a color toner image onto a transparent transfer medium. However, it is difficult to uniformly fix the color toner onto the transfer medium, and the surface of the image becomes uneven.

As a result, when used as a transmission type original, the light that should be transmitted through the image is scattered or reflected, making it impossible to obtain a color image with the desired translucency.

The following means and methods have been proposed to solve these problems.

(2) A method of applying a liquid polymer synthetic resin onto a fixed color toner image, which is disclosed in Japanese Patent Application Laid-Open No. 59-184381.

(2) A device for attaching a thermal adhesive film to an electrophotographic film on which an image has been formed, as disclosed in Japanese Patent Application Laid-open No. 60-22154.

(2) A transfer medium having a toner-receiving layer made of a thermoplastic resin on the surface of an image support disclosed in JP-A No. 82-232871.

However, all of the above-mentioned means and methods have the following practical problems.

The method (2) has a problem in that the color toner image after fixing needs to be further processed, making the processing process complicated. Furthermore, since organic solvents are used, there is a risk of fire as well as being harmful to the human body.

In case (2) above, not only is the process complicated as in case (2) above, but also it is necessary to install a device for pasting the thermal adhesive film inside or outside the printer, copier, etc., which increases the size of the device and increases the cost. There are problems such as an increase in the amount of heat, an increase in power consumption to heat the thermal adhesive film, and problems with heat countermeasures for the device.

According to the experiments conducted by the present inventors, the transfer medium of (2) above has the 6th
As shown in the figure, when an image is formed by providing a toner-receiving layer 2 made of a thermoplastic resin on a transparent substrate 1, if the thermoplastic resin has a melting point equal to or higher than that of the toner, the toner-receiving layer 2 The top 2 toner 3 softens first.

As a result, toner aggregation occurs, causing reflection, diffusion, and a decrease in image sharpness. Also,
Deterioration of the light transmittance of the image is often observed depending on the amount of adhesion, other developing conditions, and fixing conditions, and it has been found that the appropriate conditions for fixing the toner-receiving layer cannot necessarily be applied as they are.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned conventional problems, and aims to provide a translucent transfer medium capable of creating a good translucent color image. That is.

[Structure of the Invention] (Means for Solving the Problems) The present invention transfers color toner by electrophotographic forming method.
A transfer medium that is fixed to form a translucent image, characterized in that a toner image holding layer containing a thermoplastic resin having a lower softening point than the color toner is formed on the surface of a transparent substrate. It is.

Hereinafter, a translucent transfer medium according to the present invention will be explained with reference to FIG.

In FIG. 1, 11 is a transparent base material. A toner image holding layer 12 is formed on the surface of this transparent substrate 11.

The transparent base material 11 may be any material as long as it has heat resistance and excellent light transmittance, and generally a resin film is used. Specific examples include polyester resin, polypropylene resin, boreimide resin, polyvinyl chloride resin, polystyrene resin, cellulose acetate resin, and the like. Note that the transparent base material may be colored depending on the use. Such resins include antioxidants, metal deactivators, ultraviolet absorbers,
General additives such as light stabilizers, optical brighteners, charge control agents, and slipperiness imparting agents may be mixed. Specifically, hindered phenols, hydrazines, benzotriazoles, aromatic amines, organic sulfur compounds, phosphite esters, chelating agents, benzophenones, benzotriazoles, nickel complexes, hydrophobic silica, etc. Can be mentioned.

The toner image holding layer 12 is made of a thermoplastic resin, and the thermoplastic resin must have a softening point lower than that of the toner, and must also have translucency after fixing the toner image, and must be transparent to the transparent base material. Any resin can be used without particular limitation as long as it adheres well to the resin and has a surface hardness that is practically usable.

Here, the softening point is measured according to the Vicat softening temperature test of JIS K720G. Examples of such thermoplastic resins include nylon resin, polyester resin, polycarbonate resin, polyether resin, polyethylene resin, polypropylene resin, polysulfone resin,
Polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, ethylene-vinyl acetate copolymer resin, acrylic resin, polyphenylene sulfide resin, polyphenylene oxide resin, styrene copolymer resin, fluororesin, polyacrylate resin, butyral resin, poly Examples include vinyl acetate resin, polyethylene oxide resin, polyvinyl alcohol resin, polyvinyl acetate resin, cellulose resin, and derivatives thereof. These thermoplastic resins may be used alone or in combination of two or more.

Note that the toner image holding layer may be colored depending on the purpose.

Like the resin used for the transparent base material 11, the thermoplastic resin used for the toner image holding layer 12 contains an antioxidant, a metal deactivator, an ultraviolet absorber, a light stabilizer, a fluorescent whitening agent, and a charge control agent. , general additives such as slipperiness imparting agents may be mixed. Specifically, hindered phenols, hydrazines, benzotriazoles, aromatic amines, organic sulfur compounds, phosphite esters, chelating agents, benzophenones, benzotriazoles, nickel complexes, hydrophobic silica, etc. Can be mentioned.

To form a toner image holding layer on the transparent base material 11,
Electrostatic coating method, solvent coating method, heat fusion coating method, etc. can be adopted. For example, in the solvent coating method, a solution in which the thermoplastic resin used for the toner image holding layer is dissolved in an organic solvent is used. Examples of the organic solvent include toluene, methyl ethyl ketone, cyclohexanone, 1,1,2-trichloroethane, and methylene chloride. As the coating method, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, a curtain coating method, etc. can be adopted.

The thickness of the transparent base material 11 and the toner image holding layer 12 may be determined by any thickness, provided that a toner image can be formed on the holding layer by an electrophotographic developing/transfer means and that the toner image can be fixed by heating. It can be made thicker. For example, when applied to an electrophotographic method using corona transfer and fixing with a heat roller, the thickness of the transparent base material and the toner image holding layer are preferably in the range of 50 to 200 μm and 0.1 to 20 μm, respectively. .

In the electrophotographic method employed in the present invention, electrophotographic processes such as a developing method, a transfer method, and a fixing method are not particularly limited. Examples of the developing method include a one-component method, a two-component method, a magnetic brush method, a jumping method, a contact method, and a cascade method. In this case, it is desirable to use a toner suitable for the above-mentioned developing method. Examples of the transfer method include a corona method, a roller method, a belt method, and a pressure method. Examples of the fixing method include a heat roll method, a microwave method, an oven method,
There are hot plate methods, etc.

(Function) The translucent transfer medium according to the present invention, as shown in FIG. Because of this structure, when the color toner is heated and fixed on the holding layer 12, the holding layer 12 is softened first, and then the toner is softened. As a result, as shown in FIG. 2, the color toner 13 is buried in the toner image holding layer 12, and the unevenness of the surface caused by the color toner is improved. Therefore,
Since the diffusion phenomenon or reflection phenomenon of light incident on the color toner image can be reduced, the transmittance of the color toner image increases, and a good translucent image can be obtained. In particular, by selecting the thermoplastic resin and toner used for the toner image holding layer from materials that are compatible with each other, it is possible to obtain a good translucent image with high transmittance of the -layer color toner image.

The operation of the present invention described above will be specifically explained with reference to FIG. FIG. 3 shows the optical properties in the absorption band of a color toner image formed on a holding layer using the transparent transfer medium of the present invention and a color toner image formed on a transparent transfer medium without a toner image holding layer. It shows the relationship between the transmittance concentration and the spectral transmittance in the transmission band. Note that A in the figure is a characteristic line of a color toner image formed on a holding layer using the transparent transfer medium of the present invention, and B is a characteristic line of a color toner image formed on a transparent transfer medium without a toner image holding layer. This is the characteristic line of the image.

As shown by characteristic line B in Figure 3, in a translucent transfer medium that does not have a toner image holding layer, in low-density areas of the image, the areas to which color toner is attached are affected by the viscoelasticity, surface tension, and smearing between toner particles on the transfer medium. The surface becomes uneven due to differences in softening characteristics and physical properties.

As a result, light scattering and reflection occur, resulting in a transmittance of 50% or less. In the very low density area, the area to which the color toner is attached does not cover the entire surface of the transfer medium, so there are many transparent areas of the transfer medium. As a result, the transmittance is 50%
This is a large value.

On the other hand, as shown in characteristic line A, the translucent transfer medium of the present invention has a toner image holding layer made of a thermoplastic resin with a softening point lower than that of the toner, so the portion to which the color toner image is attached is a toner image holding layer. The toner melts together, and even in low-density areas, the toner and image surface are less affected by light diffusion and reflection, and a decrease in transmittance can be prevented. In high-density areas of the image, the amount of color toner adhered is large, so the toners melt together, reducing the effects of diffusion and reflection on the surface of the toner image, and reducing the difference caused by the presence or absence of the retaining layer.

Transmittance perceived as light transmittance varies depending on the individual, but it is generally necessary to have a transmittance of 50 to 60% or more in each transmission band of the color toner image of each color.
With the above-mentioned transparent transfer medium of the present invention, it is possible to obtain a good transparent image having a color toner image that fully satisfies the above-mentioned transmission rate.

(Example) Examples of the present invention will be described in detail below.

Example 1 First, acrylonitrile-styrene copolymer resin: J
Softening point measured according to IS K720B Vicat Softening Temperature Test 1. OB”C (product name Nirai Tatsuku A120PC manufactured by Mitsui Toatsu Co., Ltd.) 5% toluene 95 blind 1
% to prepare a coating solution. Next, the thickness is 10
A translucent transfer medium was prepared by applying the coating solution onto a 0 μm polyethylene terephthalate film to a thickness of 5 μm using a bar coater, and drying at room temperature for 10 hours to form a toner image holding layer.

On the other hand, quinacridin pigment (product name manufactured by Dainippon Ink Co., Ltd.:
WET RED 310) 2% and styrene
Acrylic acid copolymer: Softening point 145°C measured according to the JIS K720B Vika-nto softening temperature test (product name manufactured by Sanyo Chemical Co., Ltd.: Hymer TB100O) 97°C
% and hydrophobic phosphoric acid 1 wt% (
Pink) was prepared.

Next, using the translucent transfer medium and magenta toner, a Toshiba copying machine (BD33) having a structure shown in FIG.
An OHP image was formed using a non-magnetic component development method and a heat roller fixing method using a modified machine (No. 10).

In FIG. 4, 21 is a photosensitive drum 21 that rotates, for example, in a clockwise direction. A charging member 22, a developing mechanism 23, a transfer member 24, a peeling member 25, and a cleaning member 26 are arranged around the photosensitive drum 21 in this order in the rotational direction of the drum 21. The developing mechanism 23 includes a developing container 27, a developing roller 2B, a toner supply roller 29, and a layer regulating member 30. The developer container 27
Toner is stored inside.

The developing roller 28 is placed in the drum 2 in the container 27.
The container 27 is placed facing the container 27 with a predetermined gap therebetween.
The toner inside is supplied to the drum 21. The toner supply roller 29 is arranged in the container 27 so as to face the developing roller 28 with a predetermined gap therebetween, and supplies toner to the surface of the developing roller 28 . The layer regulating member 30 is arranged within the container 27,
The toner supplied from the toner supply roller 29 to the developing roller 28 is formed on the surface of the cola 28 to a predetermined thickness.

Ru. A fixing roller 31a is installed downstream of the photosensitive drum 21.
, 31b are arranged. Note that 32 in the figure is a supply section for the translucent transfer medium 33, and 34 is a discharge section for the transfer medium 33.

Comparative Example 1 An OHP image was produced in the same manner as in Example 1, except that a translucent transfer medium consisting only of a polyethylene terephthalate film on whose surface a toner image holding layer of acrylonitrile-styrene copolymer resin was not formed was used. did.

Example 2 First, polyester resin: Softening point 100°C (
Manufactured by Arayo Kagaku Co., Ltd. Product name: KR-1446) 10vt%
toluene 50wt% and methyl ethyl ketone 40wt%
A coating solution was prepared by dissolving it in Next, the thickness is 10
A translucent transfer medium was prepared by applying the coating solution to a thickness of 1 μm on a 0 μm polyethylene terephthalate film using a bar coater, and drying at room temperature for 1 D to form a toner image holding layer.

On the other hand, azo pigment (manufactured by Hoechst, trade name: Permane)
nt Yellow DHG t, ransp)
1.5wt% and polystyrene tree &: JIS [72
Softening point measured according to the Vicat softening temperature test of 0B: 136°C (product name manufactured by Kao Corporation; NE-2155) 97
vt% and polypropylene wax (product name manufactured by Sanyo Chemical Co., Ltd.; B60P) lvt% and hydrophobic silica 0.5ν
A yellow toner consisting of t% was prepared.

Next, an OHP image was formed using the translucent transfer medium and the yellow toner by a two-component magnetic brush development method and a heat roller fixing method using a modified Toshiba copying machine RheoDry 3810 having the structure shown in FIG. 5, which will be described later. . In FIG. 5, 21 is a photosensitive drum 2 rotating clockwise, for example.
It is 1. A charging member 2 is placed around the photosensitive drum 21.
2. A developing mechanism 23, a transfer member 24, a peeling member 25, and a cleaning member 26 are sequentially arranged in the rotational direction of the drum 21. The developing mechanism 23 includes a developing container 27 containing toner, and a developing roller 28 that is disposed to face the drum 21 with a predetermined gap and supplies the toner in the container 27 to the drum 21. ing. At a stage subsequent to the photosensitive drum 21, fixing rollers 31a, 3 are installed.
1b is placed. Note that 32 in the figure is a supply section for the translucent transfer medium 33, and 34 is a discharge section for the transfer medium 33. Comparative Example 2 An OBP image was produced in the same manner as in Example 2, except that a translucent transfer medium consisting only of a polyethylene terephthalate film without a polyester resin toner image holding layer formed on its surface was used.

Example 3 First, styrene-methyl methacrylate copolymer
I: Softening point 100°C measured according to the Vicat softening temperature test of JIS K7206 (Product name: Ethylene MS300, manufactured by Nippon Steel Chemical Co., Ltd.) 5vt% toluene 65
vt% and 30vt% of methyl ethyl ketone to prepare a coating solution. Subsequently, the coating solution was applied onto a polyethylene terephthalate film having a thickness of 100 μm to a thickness of 2 μm using a bar coater, and dried at room temperature for 10 hours to form a toner image holding layer, thereby forming a transparent transfer medium. was created.

On the other hand, copper phthalocyanine pigment (manufactured by Dainichiseika Chemical Co., Ltd., trade name:
ChroaoNne blue 34HEAB) l
vt% and copper phthalocyanine pigment (trade name, manufactured by Dainichiseika Chemical Co., Ltd.:
TSG-1) 1wt%, polyester resin: JIS
Softening point 132°C measured according to Vicat softening temperature test of K7206 (Product name: KR-14 manufactured by Arayo Kagaku Co., Ltd.)
52) 98vt%, polypropylene wax (product name: 660P, manufactured by Sanyo Chemical Co., Ltd.) 1vt%, and hydrophobic silica
A cyan toner consisting of lvt% was prepared.

Next, an OHP image was formed using the translucent transfer medium and the cyan toner using a modified Toshiba copying machine RheoDry 511O by a two-component magnetic brush development method and an oven fixing method.

Comparative Example 3 Polyester resin i: A solution with a softening point of 155°C (trade name: KR-1477, manufactured by Arayo Kagaku Co., Ltd.) measured according to JIS K720B Vicat softening temperature test was applied on the surface of a polyethylene terephthalate film and dried. In addition to using a translucent transfer medium on which a toner image holding layer was formed,
An OHP image was produced in the same manner as in Example 3.

The obtained OHP images of Examples 1 to 3 and Comparative Examples 1 to 3 were measured using a transmission densitometer (manufactured by Macbeth Co., Ltd., trade name, TD-
504), spectrophotometer (product name manufactured by Shimadzu Corporation; U
An objective transmittance evaluation was performed using a camera (V-260), and a subjective transmittance evaluation was performed using a Hortapul OHP 313R manufactured by Ricoh. For objective evaluation, the transmittance in the transmission band of an image having a transmission density of 0.45 was determined. The results are shown in Table 1 below.

Table 1 As is clear from Table 1 above, the OHPs of Examples 1 to 3
It can be seen that all of the images have superior translucency compared to the same images of Comparative Examples 1 to 3.

[Effects of the Invention] As detailed above, according to the present invention, since the present invention has a toner image holding layer capable of burying color toner and improving surface unevenness caused by the color toner, the light incident on the color toner image is It is possible to provide a translucent transfer medium capable of creating a good translucent color image with improved transmittance of a color toner image by reducing the diffusion phenomenon or reflection phenomenon.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a translucent transfer medium according to the present invention;
FIG. 2 is a schematic diagram for explaining the action of the translucent transfer medium, and FIG. 3 shows the color toner image formed on the retaining layer using the translucent transfer medium of the present invention and the toner image retaining layer. A characteristic diagram showing the relationship between the optical transmittance density of the absorption band and the spectral transmittance of the transmission band in a color toner image formed on a transparent transfer medium that does not have any Figure 5 is a schematic diagram showing the Toshiba copying machine (Reodory 3810 modified machine) used in Example 2. Figure 6 is a schematic diagram showing the problems with conventional translucent transfer media. FIG. 3 is a schematic diagram for explaining the points. 11... Transparent base material, 12... Toner image holding layer, 13
...Color toner image, 21...Photosensitive drum, 22.
...Charging member, 23...Developing mechanism, 24...Transfer member, 31a, 31b...Fixing roller, 33...
Transparent transfer medium.

Claims (1)

[Claims] In a transfer medium for forming a translucent image by transferring and fixing color toner by an electrophotographic formation method, a toner image holding layer containing a thermoplastic resin having a lower softening point than the color toner is formed on the surface of a transparent substrate. A translucent transfer medium characterized by: