JP3249651B2 - Photosensitive capsule mixture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive capsule mixture used for an image forming apparatus or a printer.

[0002]

2. Description of the Related Art Conventionally, a photosensitive capsule containing an image forming material such as a dye precursor, a dye and a pigment and changing its mechanical strength in response to light is disclosed in JP-A-63-269146. It has been disclosed. In addition, a photosensitive capsule that encloses the image forming material and changes its mechanical strength in response to light is used. After the capsule is exposed, the image is received by a developing method that destroys only the weak toner by pressing or the like. An image forming apparatus for forming an image on paper is disclosed in JP-A-63-316.
No. 038 and the like.

[0003]

However, in these photosensitive capsules, high sensitivity and short-time exposure are necessary conditions. To achieve these, generally, γ of the characteristic curve becomes large, and L However, there has been a problem that the contrast becomes small and the contrast becomes high.

Here, the characteristic curve is a curve representing the relationship between the exposure amount E (log E) and the image density D as shown in FIG. 1 in a silver halide photographic material, and the width L of a portion having a linear characteristic is tolerated. Degree, the slope is α, tanα = γ (gamma)
Call. Also, when the γ is large, an image having a large density difference is obtained as compared with the difference in brightness of the document, and this is called a high contrast. Conversely, when γ is small, a subtle shadow can be formed. Is called soft.

In the image forming apparatus as described above,
In the low energy region, the photosensitive capsule is not cured and the entire image forming material is released, so that the image density is increased. As the energy is increased, the capsule is cured and the image density is decreased. Therefore, the characteristic curve of the photosensitive capsule is shown in FIG.
As shown in the figure, unlike the characteristic curve of the photographic material, it falls to the right.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a photosensitive capsule mixture which does not exhibit high contrast even when high sensitivity and short exposure time are achieved.

[0007]

According to the present invention, there is provided a photosensitive capsule mixture comprising a dye, a pigment and a dye.
A mixture of photosensitive capsules containing an image forming material selected from precursors and a photosensitive material that cures in response to light, and has the same image forming material and the same photosensitive wavelength. A photosensitive capsule containing the photosensitive material,
A plurality of photosensitive capsules having the same photosensitive wavelength are provided, and the photosensitive capsule having the same photosensitive wavelength has a different concentration of the image forming material for each kind.

[0008]

The photosensitive capsule mixture of the present invention having the above-mentioned structure has a small γ and is soft, and it is easy to produce an intermediate color.
Exposure conditions also become easier to control.

Normally, simply changing the content of the image forming material in the photosensitive capsule changes the image density, so that γ of the characteristic curve changes, but it is unlikely that L also changes. However, even if the content of the image forming material is changed, even the fact L tends to change. It is considered that this occurs because light absorbed by the photosensitive material is blocked by the image forming material. Therefore, it is considered that by changing the content of the image forming material, the light absorption amount of the photosensitive material in the capsule changes, and as a result, the curing sensitivity of the capsule also changes.

[0010]

Embodiments of the present invention will be described below. The photosensitive capsule includes an outer shell and a liquid component inside the outer shell. The outer diameter of the photosensitive capsule is desirably about several μm to several tens μm, but is not limited thereto.

The liquid component comprises at least an image forming material such as a dye and a photosensitive substance.

As the above-mentioned image forming material, a dye, an inorganic pigment, an organic pigment, a dye precursor which changes color by reacting with a developer or the like can be used. Desirably, xanthene dyes, coumarin dyes, merocyanine dyes, thiazine dyes,
Dyes such as azine dyes, methine dyes, oxazine dyes, phenylmethane dyes, cyanine dyes, azo dyes, anthraquinone dyes, pyrazoline dyes, stilbene dyes, quinoline dyes, leuco dyes, etc., and monoazo pigments , Disazo pigments, azo lake pigments, quinacridone pigments, perylene pigments, anthrapyrimidine pigments,
Organic pigments such as isoindolinone pigments, threne pigments, phthalocyanine pigments, carbon black, graphite, red iron oxide, titanium oxide, molybdenum red, cadmium red,
Inorganic pigments such as cobalt blue and chrome green;

Desirable dye precursors include diphenylmethane compounds, triphenylmethane compounds, bisphenylmethane compounds, xanthene compounds, thiazine compounds, fluorane compounds, spiropyran compounds, and mixtures thereof. is there. In the present invention, it is necessary to mix and use a plurality of capsules having different contents of the image forming material. For example, in a magenta capsule, the content concentration of the image forming material is 3%.
%, 5%, 7%, and 3 types of capsule mixture, 2 types of yellow color are 4% and 6%, and 4% and 6% of cyan color.
% And 7%. At this time, the number of types of capsules having different contents of the image forming material is not particularly limited. By mixing and using a plurality of capsules having different contents of the image forming material in this manner, γ of the characteristic curve is reduced, so that an intermediate color can be easily obtained and the exposure condition can be easily controlled.

The photosensitive material is a resin which cures in response to light and is usually used by mixing a photopolymerization initiator and a polymerizable substance.

The polymerizable substance may be a monomer, a polymer, an oligomer, a copolymer or a tripolymer. Desirably, N-vinyl-2-pyrrolidone, bisphenol A diacrylate and methacrylate,
Examples include tripropylene glycol diacrylate and methacrylate, polyethylene glycol diacrylate and methacrylate, pentaerythritol triacrylate and methacrylate, dipentaerythritol hexaacrylate and methacrylate, trimethylolpropane triacrylate and methacrylate, oligoester acrylate and methacrylate, and the like. These photocurable resins may be used alone or in combination of two or more.

The photopolymerization initiator is one which initiates polymerization of a resin in response to light and comprises an aromatic carbonyl compound,
Acetophenones, organic peroxides, diphenylhalonium salts, organic halides, 2,4,6-substituted-S-triazines, 2,4,5-triarylimidazole dimers, azo compounds, dye borate complexes, Iron arene complex,
And titanocene compounds.

Preferably, benzophenone, benzyl,
Xanthone, thioxanthone, anthraquinone, acetophenone, 2,2-dimethyl-2-morpholino-4 '
-Methylthioacetophenone, benzoyl peroxide, 3,3 ', 4,4'-tetra (tert-butylbenzophenone), diphenyliodonium bromide,
Diphenyliodonium chloride, carbon tetrachloride, carbon tetrabromide, 2,4,6-tristrichloromethyl-S-triazine, [(η5-2,4-cyclopentadiene-1
-Yl) [(1,2,3,4,5,6-η)-(1-methylethyl) benzene] iron (1+) hexafluorophosphate (1-)] and the like. These photopolymerization initiators may be used alone or as a mixture of two or more.

The photosensitive capsule having the above structure can be produced by a method which is already known in the art. For example, a phase separation method from an aqueous solution as described in U.S. Pat. Nos. 2,800,457 and 2,800,458, JP-B-38-1974 and JP-B-42-4.
No. 46, No. 42-771, an interfacial polymerization method, JP-B-36-9168, JP-A-51-90.
No. 79, etc., by in-s polymerization by monomer polymerization
Itu method, British Patent Nos. 952807 and 96507
No. 4, but not limited thereto. These production methods can be used without particular change even if the content of the image forming material is different.

Materials for forming the outer shell include gelatin, gum arabic, starch, sodium alginate, polyvinyl alcohol, polyethylene, polyamide, polyester, polyurethane, polyurea, polyurethane, polystyrene, nitrocellulose, ethylcellulose, methylcellulose, melamine-formaldehyde. Resins, urea-formaldehyde resins and the like, and copolymers thereof are used, but materials that sufficiently transmit light are more preferable.

Next, the present invention will be described by way of examples. However, the present invention is not limited to these examples, and the materials used, their ratios and production conditions are changed within the ranges described so far. It can also be implemented.

Example 1 This contains a yellow pigment as an image forming material,
This is an example of a yellow image recording microcapsule having a photosensitivity around 450 nm.

Using a mixture of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate in a ratio of 3: 4, 100 parts by weight of a high molecular weight polyurethane as a dispersant, and 4 parts by weight of an azobarium lake pigment dispersed therein. 0.5 parts by weight of 3-thenoyl-7-diethylaminocoumarin, 2,6-diisopropyl-N,
2 parts by weight of N-dimethylaniline and a photopolymerization initiator [(η5-2,4-cyclopentadien-1-yl)
3 parts by weight of [(1,2,3,4,5,6-η)-(1-methylethyl) benzene] iron (1+) hexafluorophosphate (1-)] are added, and the mixture is heated at 100 ° C. for 10 minutes. Thus, a hydrophobic first liquid component was obtained.

Next, a second liquid component was obtained by using 6 parts by weight of the same azobarium lake pigment instead of 4 parts by weight of the first liquid component.

Next, the hydrophobic first liquid component was added to 100 cc of a 1: 1 aqueous solution of a 5% polystyrenesulfonic acid partial sodium salt aqueous solution and a 5% styrene-maleic anhydride copolymer aqueous solution as an emulsifier. In addition, the first liquid component is present as a droplet having a size of 5 to 30 μm in the aqueous solution after stirring at 6000 rpm for 5 minutes with a homogenizer.
A so-called O / W emulsion was obtained. Similarly, the second liquid component was added to the aqueous solution to obtain an O / W emulsion, which was mixed with the emulsion of the first liquid component.

Separately, commercially available melamine powder was added to a 37% aqueous formaldehyde solution, adjusted to pH 9.0 with a sodium hydroxide solution, and heated at a water temperature of 60 ° C. for 30 minutes to obtain a melamine / formaldehyde prepolymer.

Melamine / formaldehyde prepolymer is added to the previously prepared and mixed O / W emulsion, and the mixture is stirred for 5 hours at 100 to 300 rpm while heating so that the water temperature becomes 80 ° C. with an azimohomomixer. Then, the mixture was adjusted to PH7 and cooled to room temperature.
As a result, a melamine-formaldehyde resin wall material was deposited around the droplets of the O / W emulsion, and yellow photosensitive microcapsules having image forming material contents different from 4% and 6% were obtained.

Next, a conventional capsule manufacturing method will be described for comparison with the capsule manufactured in the above embodiment.

COMPARATIVE EXAMPLE 100 parts by weight of a mixture of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate in a ratio of 4: 4 was dispersed in 5 parts by weight of an azobarium lake pigment using a high-molecular polyurethane as a dispersant.
To this is added 3-thenoyl-7-diethylaminocoumarin 0.1.
5 parts by weight, 2,6-diisopropyl-N, 2 parts by weight of N-dimethylaniline, and a photopolymerization initiator [(η5-2,
4-cyclopentadien-1-yl) [(1,2,3,
4,5,6-η)-(1-methylethyl) benzene] iron (1+) hexafluorophosphate (1-)], and the mixture was heated at 100 ° C. for 10 minutes to remove the hydrophobic liquid component. Obtained.

Next, the hydrophobic liquid component was added to 100 cc of a 1: 1 aqueous solution of a 5% polystyrenesulfonic acid partial sodium salt aqueous solution and a 5% styrene-maleic anhydride copolymer aqueous solution as an emulsifier, 6 with a homogenizer
After stirring at 000 rpm for 5 minutes, an O / W emulsion having a size of 5 to 30 μm was obtained.

Separately, commercially available melamine powder was added to a 37% aqueous formaldehyde solution, adjusted to pH 9.0 with a sodium hydroxide solution, and heated at a water temperature of 60 ° C. for 30 minutes to obtain a melamine / formaldehyde prepolymer.

A melamine / formaldehyde prepolymer is added to the O / W emulsion prepared above, and the mixture is stirred at 100 to 300 rotations with an azihomomixer or the like, and is held for 5 hours while being heated to a water temperature of 80 ° C., Thereafter, the pH was adjusted to pH 7 and cooled to room temperature. As a result, melamine-formaldehyde resin wall material was deposited around the droplets of the O / W emulsion, and conventional yellow photosensitive microcapsules were obtained.

A characteristic curve was prepared by using the above-mentioned capsules of the present invention and comparative capsules. The results are shown in FIG. In the figure, the dashed line A is the characteristic curve of the comparative capsule, and the solid line B is the capsule of this embodiment of the present invention. As is apparent from this, the energy at which the image density starts to decrease is the same, and the sensitivity has not decreased. However, it can be seen that γ is gentler in the capsule of the example, the formed image is softer, an intermediate color is easily produced, and the exposure condition is easier to control.

[0033]

As is apparent from the above description,
The photosensitive capsule mixture of the present invention comprises a dye, a pigment, and a dye.
A mixture of photosensitive capsules containing an image forming material selected from precursors and a photosensitive material that cures in response to light, having the same image forming material and the same photosensitive wavelength. A plurality of photosensitive capsules containing the photosensitive material are provided for the same photosensitive wavelength, and the photosensitive capsule having the same photosensitive wavelength has a different concentration of the image forming material for each type. So
Since the formed image is soft, an intermediate color is easily produced and the exposure condition is easily controlled.

[Brief description of the drawings]

FIG. 1 is a view showing a characteristic curve of a general silver halide photographic material.

FIG. 2 is a diagram showing a characteristic curve of a conventional photosensitive capsule.

FIG. 3 shows a characteristic curve of the photosensitive capsule mixture of the present invention,
FIG. 9 is a diagram comparing characteristic curves of conventional photosensitive capsules.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-163450 (JP, A) JP-A-2-10343 (JP, A) JP-A-61-130945 (JP, A) JP-A-3-3 296753 (JP, A) JP-A-2-293849 (JP, A) JP-A-63-261348 (JP, A) JP-A-5-265203 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 7/004 514 G03G 9/08 311

Claims (1)

(57) [Claims] 1. A dye, a pigment or a dye precursor selected from the group consisting of:
A mixture of photosensitive capsules containing an image forming material and a photosensitive material that cures in response to light, comprising: the same image forming material; and the photosensitive material having the same photosensitive wavelength. A plurality of photosensitive capsules are provided for the same photosensitive wavelength, and for the photosensitive capsule having the same photosensitive wavelength,
A photosensitive capsule mixture, wherein the concentration of the image forming material is different for each type.