JP2674105B2 - Developer for electrostatic latent image development - Google Patents

Description

TECHNICAL FIELD The present invention relates to a developer for developing an electrostatic latent image that wet develops an electrostatic latent image formed by an electrophotographic process or the like, and particularly wet development. The present invention relates to a novel electrostatic latent image developing material that can be handled as a tape, sheet, etc. even though it is an agent.

[Conventional technology]

In the field of image forming technology, a method of selectively irradiating light on a uniformly charged photoconductor according to an image signal and developing the formed electrostatic latent image is generally called an electrostatic photography process. being called.

In such an electrostatic photography process, a dry developing method and a wet developing method are known as a method for developing an electrostatic latent image, and they have different advantages and disadvantages. Is the current situation.

For example, the dry developing method has an advantage that it is excellent in handleability and storability of the toner because the powder of the colorant is simply scattered and attached to the electrostatic latent image in principle.

However, as seen in video printers and the like for printing electronic still photographs, in reality, in order to respond to the demand for high-quality images, which has been increasing in recent years, it is necessary to give a step to wet development.

On the other hand, the wet development method is a method that uses a liquid developer in which a dye or pigment as a colorant is dispersed in an insulating liquid medium, and it is possible to obtain a resolution and gradation comparable to those of silver salt photographs. In addition, when a pigment is used as a colorant, the formed image has excellent weather resistance.

However, since the developer is a liquid, it is very disadvantageous in terms of handleability, for example, frequent maintenance is required to always realize stable image formation.

Further, regardless of whether the dry developing method or the wet developing method is used, the developing device to be used generally tends to have a complicated structure and a large scale, and it is difficult to adopt it in a developing device for consumer use such as a general household. .

[Problems to be solved by the invention]

From such a situation, for example, in the above-mentioned video printer, in order to simplify the apparatus configuration, a sublimation type thermal transfer system or an inkjet system in which a sublimable ink is vaporized by a thermal head and transferred to a recording sheet is used. Many.

However, these methods are naturally inferior to the above-mentioned electrostatic photography process in terms of resolution and gradation, and it is almost impossible to form an image comparable to silver halide photography.

Therefore, the present invention has been proposed in view of such a conventional situation, and is for a novel electrostatic latent image development that waits for high image quality by wet development and good handling property equivalent to a sublimation type thermal transfer system. The purpose is to provide a developer.

[Means for solving the problem]

The present inventors have conducted extensive studies to achieve the above-mentioned object, and as a result, instead of a conventional liquid electrically insulating medium, use an organic substance that is solid at room temperature and changes solid-liquid by heating and cooling. Thus, it has been found that the wet developer can be formed into a sheet or a tape, and the handling property thereof can be significantly improved.

The present invention has been completed based on such knowledge, and a plurality of developers in which colorants having different colors are dispersed are held on a substrate in different regions, and the developer is at least It is characterized in that a colorant is dispersed in an electrically insulating organic substance that is solid at room temperature and changes solid-liquid by heating and cooling.

Here, colorants of different colors such as yellow, magenta, cyan, and, if necessary, black are dispersed in the plurality of developers held on the substrate. The developer of each color may be applied separately in a predetermined area,
A full-color image can be formed by sequentially developing the electrostatic latent image with the developer in each of these areas.

Further, in the case where the developer regions of a plurality of colors are formed, some color mixture preventing layer may be provided between the developer regions in order to prevent color mixture between the developers, especially when the developer becomes liquid by heating.

[Action]

In the developer for electrostatic latent image development of the present invention, the developer held on the substrate changes into a solid-liquid state by heating and cooling, and functions as a wet type developer by being brought into contact with the electrostatic latent image in a heated state.

Further, since the developer is held on the substrate, it is handled in the form of a sheet, a tape or the like like a sublimation type ink film or the like, and the handling property and storage property thereof are remarkably improved.

〔Example〕

Hereinafter, specific embodiments to which the present invention is applied will be described with reference to the drawings.

First, prior to the description of the examples, the developer used in each example will be described.

The developer used in the present invention is one in which a colorant is dispersed in an electrically insulating organic substance that is solid at least at room temperature and changes into a solid-liquid state by heating and cooling.

Here, the electrically insulating organic material is an organic material that is solid at least at room temperature. The melting point is set to 30 ° C. or higher, more preferably 40 ° C. or higher, in consideration of normal use environment and handleability. Although the upper limit of the melting point is not particularly limited, it is practically about 100 ° C, more preferably 80 ° C or less. This takes into consideration that extra energy is consumed for heating even if the melting point is too high, and that the heat-resistant temperature of the material generally used as the substrate should not be exceeded when it is formed on the substrate and used. That is all.

Materials that meet these requirements include paraffins,
Waxes, and mixtures thereof. First, as paraffins, there are various normal paraffins having 19 to 60 carbon atoms ranging from nonadecane to hexacontan. Examples of the waxes include vegetable waxes such as carnauba wax and cotton wax, animal waxes such as beeswax, ozokerite, and petroleum waxes such as paraffin wax, microcrystalline wax and petrolatum. These materials are dielectrics having a dielectric constant ε of about 1.9 to 2.3.

Further, polyethylene, polyacrylamide, or a homopolymer or copolymer of polyacrylate such as poly-n-stearyl acrylate or poly-n-stearyl methacrylate (for example, copoly-n-stearyl acrylate ethyl methacrylate) has a long alkyl group in its side chain. Although crystalline polymers can be used, the above paraffins and waxes are preferable in consideration of the viscosity at the time of heating.

As the colorant dispersed in the electrically insulating organic material, conventionally known inorganic pigments, organic pigments, dyes and mixtures thereof can be used.

For example, inorganic pigments include chromium pigments, cadmium pigments, iron pigments, cobalt pigments, ultramarine, navy blue and the like. Organic pigments and dyes include Hansa Yellow (CI11680) and Benzidine Yellow G (CI210
90), Benzidine Orange (CI21110), Fast Red (CI37085), Brilliant Carmine 3B (CI1
6015-LaKe), phthalocyanine blue (CI74160),
Victoria Blue (CI42595-LaKe), Spirit Black (CI50415), Oil Blue (CI74350), Alkali Blue (CI42770A), First Scarlet (CI12315), Rhodamine 6B (CI45160), Rhodamine Lake (CI45160-LaKe), Fast Sky Blue ( CI74200-LaKe), nigrosine (CI50415), carbon black and the like. These can be used alone or as a mixture of two or more kinds, and those having a desired color may be selected and used.

In addition to these electrically insulating organic substances and colorants, a resin may be used in combination with the developer for the purpose of improving dispersibility and fixing property of the colorant. As such a resin, known materials can be appropriately selected and used. For example, rubbers such as butadiene rubber, styrene-butadiene rubber, cyclized rubber, natural rubber, styrene resin, vinyltoluene resin, acrylic resin can be used. Resin, methacrylic resin, polyester resin, polycarbonate resin, synthetic resin such as polyvinyl acetate resin, rosin resin, hydrogenated rosin resin,
Examples include alkyd resins containing modified alkyd such as linseed oil modified alkyd resin and natural resins such as polyterpenes. In addition, modified phenol resins such as phenol resins and phenol formalin resins, pentaerythritol phthalate, coumarone-indene resins, ester gum resins and vegetable oil polyamide resins are also useful, and polyvinyl chloride and chlorinated Halogenated hydrocarbon polymers such as polypropylene, synthetic rubbers such as vinyltoluene-butadiene and butadiene-isoprene, long-chain alkyl groups such as 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, lauryl acrylate and octyl acrylate Polymers of acrylic monomers or copolymers of them with other polymerizable monomers (for example, styrene-lauryl methacrylate copolymer, acrylic acid-lauryl methacrylate copolymer, etc.), polyethylene Polyolefins, etc., polyterpenes, and the like can also be used.

Further, a charge donor is usually added to the developer, and the developer used here is no exception. Examples of the charge donor used include metal salts of fatty acids such as naphthenic acid, octenoic acid, oleic acid, stearic acid, isostearic acid and lauric acid, metal salts of sulfosuccinic acid esters, oil-soluble sulfonic acid metal salts and phosphoric acid. Ester metal salts, metal salts such as abietic acid, aromatic carboxylic acid metal salts, aromatic sulfonic acid metal salts and the like.

In addition, in order to improve the electrostatic charge of the colorant, SiO ₂ , A
_{l 2 O 3, TiO 2,} ZnO, Ga 2 O 3, In 2 O 3, GeO 2, may be added to SnO _2, PbO _2, metal oxide particles, and mixtures thereof, such as MgO as a charge enhancer .

Regarding the compounding ratio of each component described above, the colorant is preferably 0.01 to 100 g, and more preferably 0.1 to 10 g based on the molten state 1 of the electrically insulating organic material. Similarly, the amount of the electric donor is usually 0.001 to 10 g, preferably 1 to 1.
It is in the range of 0.01 to 1 g. Further, the charge enhancer is added in a weight ratio of not more than 2 times, preferably not more than the same amount with respect to the colorant.

The above-mentioned developer is held on the substrate to form a developer for electrostatic latent image development. The constitution of each embodiment will be described below.

FIG. 1 shows a developer having the simplest structure among the developers to which the present invention is applied, in which the above-mentioned developer (2) is applied over the entire surface of a sheet-like substrate (1).

As the material of the substrate (1), metals such as Cu and Al, polymer films such as polyethylene terephthalate, polypropylene, polycarbonate and polyamide, paper (natural paper,
Synthetic paper and the like), and composite materials thereof and the like can be mentioned, and those having flexibility are usually used, but they do not necessarily have flexibility.

FIG. 2 shows an example in which a porous substrate is used, in which the developer (2) of the porous substrate (3) is held in a state of being impregnated and solidified.

The porous substrate (3) may be any as long as it can be impregnated with the developer (2), natural paper,
In addition to paper such as synthetic paper, natural fibers such as vegetable fibers such as cotton and hemp, silk such as animal fibers such as wool, organic substances such as polyamide, polyester, polyacetal, polyurethane, glass, ceramics, carbon, etc. It is possible to use cloths, non-woven fabrics, etc. made of synthetic fibers made of the above inorganic materials. Further, it may be a mesh of metal or organic polymer, or polymer foam such as polyurethane foam.

Porous substrate (3) impregnated and solidified with this developer (4)
Alternatively, as shown in FIG. 3, the sheet-like base body (1) may be lined and reinforced.

Further, the plurality of developers held on the substrate (1) or the porous substrate (3) are made to correspond to a plurality of colors by dispersing colorants having different colors, and each color region is one substrate. It is formed by being painted over.

For example, FIG. 4 shows a yellow color developer layer Y, a magenta color developer layer M, and a cyan color developer layer C formed on a substrate (1), which enables full-color image formation. is there. In the case of forming a full-color image, a black developer layer region may be added as necessary in addition to the yellow, magenta, and cyan colors.

Similarly, as shown in FIG. 5, a yellow developer Y, a magenta developer M, and a cyan developer C are also applied to the porous substrate (3) laminated on the substrate (1). Each region may be impregnated and solidified. Of course, as shown in FIG. 6, these yellow developer Y, magenta developer M, and cyan developer C are impregnated and solidified to form a porous substrate (3 ) Can also be treated as it is as a developer for electrostatic latent image development.

By the way, when the developer regions of a plurality of colors are formed on the same substrate as described above, there is a possibility that color mixing will occur especially during heating and melting.

Therefore, for example, as shown in FIG.
You may make it provide the color mixing prevention layer (4) between the area | region which consists of M and C.

The color mixing prevention layer (4) may be of any type as long as it merely serves as a spacing.
In particular, it is preferable to use a liquid absorbing material [for example, the same material as the above-mentioned porous substrate (3)], a liquid repellent material, or the like.

Further, as shown in FIG. 5 or FIG. 6, when the porous substrate (3) is impregnated and solidified with the developers Y, M and C of the respective colors, if the developer regions of the respective colors are formed at a predetermined interval,
The porous substrate (3a) between the regions functions as the color mixing prevention layer.

In order to develop an electrostatic latent image using the above-mentioned electrostatic latent image developing material, the following method may be used. Hereinafter, the first
A method of developing an electrostatic latent image will be described with reference to an example shown in the drawing.

As shown in FIG. 8, the photosensitive substrate (5) is, for example, a sheet-like substrate (5a) on which a photosensitive layer (5b) is formed, and the photosensitive layer (5b) is charged. A latent image with a negative charge corresponding to image information is formed by the process and the exposure process.

Here, in order to develop the photosensitive base material (5) on which the latent image of the negative charge is formed by the developing material of this embodiment, the developer (2) is superposed so as to come into contact with the photosensitive layer (5b). ,
It suffices to send it out while pressing it with a roll (6) provided with a heating means.

When the developer (2) and the photosensitive layer (5b) are brought into contact with each other and heated by the roll (6) as described above, the developer (2) becomes liquid and the colorant (7) contained in the developer (2).
Migrate toward the negatively charged site and adhere.
After that, remove the coloring agent (7) attached to unnecessary parts,
An image is formed on the photosensitive base material (5) by passing through a charge eliminating step, a fixing step and the like.

During development, the photosensitive substrate (5) and the developer (2)
Since there is a risk that the image quality will be deteriorated if the and solidify immediately after contacting with each other, it is preferable to provide a heating means on the photosensitive base material (5) itself, a stage for fixing the photosensitive base material (5) or the like for heating. .

In fact, the inventors of the present invention produced a sheet-shaped developer as described above and tried to develop an electrostatic latent image, and as a result, a good image excellent in resolution and vividness and comparable to a silver halide photograph was stably obtained. Was obtained.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and materials, shapes, and the like can be changed without departing from the scope of the present invention. .

〔The invention's effect〕

As is clear from the above description, since the plurality of developers of the present invention for developing an electrostatic latent image having different colors from each other are the ones in which the developers are held on the substrate, for example, similar to sublimable ink ribbons and the like. It is extremely easy to handle, and it is possible to greatly simplify the developing operation and developing device.

Further, when an electrostatic latent image is developed using the developer for developing an electrostatic latent image of the present invention, image quality similar to the wet development method can be obtained, and further, it can be discarded as it is after use. It is also suitable from the viewpoint of processing.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of an essential part showing an embodiment of a developing material to which the present invention is applied, and FIG. 2 is an enlarged cross-sectional view of an essential part showing an embodiment using a porous material for a substrate, and FIG. FIG. 3 is an enlarged sectional view of an essential part showing an embodiment in which a sheet-shaped substrate is lined on a porous substrate. FIG. 4 is an enlarged cross-sectional view of an essential part showing an embodiment in which a plurality of developer regions are formed, and FIG. 5 is an embodiment in which a plurality of developer regions are formed on a porous substrate lined with a sheet-like substrate. FIG. 6 is an enlarged cross-sectional view of an essential part showing an embodiment in which a porous substrate having a plurality of developer regions is used as a developer as it is, and FIG. 7 is an embodiment in which a color mixing prevention layer is provided. It is a principal part expanded sectional view which shows an example. FIG. 8 is a schematic diagram for explaining a method of developing an electrostatic latent image with the developing material of the present invention. 1 ... Substrate 2 ... Developer 3 ... Porous substrate 4 ... Color mixing prevention layer

Claims (2)

(57) [Claims] 1. A plurality of developers in which colorants having different colors are dispersed are held on a substrate in different regions, and the developers are solid at least at room temperature and change to solid-liquid by heating and cooling. A developer for developing an electrostatic latent image, comprising a colorant dispersed in an electrically insulating organic material. 2. The developer for developing an electrostatic latent image according to claim 1, wherein a color mixing prevention layer is formed between the developers in each area.