JPH03196158A - Electrostatic latent image developing method - Google Patents

Abstract

PURPOSE:To keep toner quantity and toner concentration supplied to a developing process constant by using solid fixing toner at a room temperature, and performing the heating contact of the fixing toner while relatively moving it to an electrostatic latent image carrier. CONSTITUTION:The fixing toner 1 is molded in a rectangular parallelopiped, and developing is performed while bringing it into contact with a photosensitive material 3 heated in advance with a heater 2 by pressing with a spring 4. In other words, the photosensitive material 3 electrified uniformly with an electrostatic charger 5 and on which the electrostatic latent image is formed by applying selective exposure with a semiconductor laser 6 is traveled in a direction of arrow head, and the rectangular parallelopiped fixing toner 1 is brought into contact with the photosensitive material 3 on which the electrostatic latent image is formed. Since the fixing toner 1 is pressed to the photosensitive material 3 with the spring 4, the toner is molten gradually according to the progression of the development, and is supplied to a part between the photosensitive material 3 and a counter electrode 7, then, the toner quantity can be kept almost constant. Thereby, it is possible to keep the supply quantity of toner almost constant, and to stably perform image formation.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a latent image developing method suitable for developing an electrostatic latent image in an electrophotographic process, etc. The present invention relates to a method for developing an electrostatic latent image, which can be developed easily and has a simplified device configuration.

[Summary of the invention]

The present invention uses a solidified toner that is solid at room temperature, and heats and contacts the solidified toner while moving it relative to an electrostatic latent image carrier, or cuts the solidified toner to form a flake and electrostatically conducts the solidified toner. By supplying it onto the latent image carrier,
An object of the present invention is to provide an electrostatic latent image developing method in which a developing device is simplified, a high-quality image can be stably developed with a simple mechanism, and the toner is easy to handle.

[Conventional technology]

An electrostatic latent image in an electrostatic process such as an electrophotographic development process is created by uniformly charging a photoreceptor made of, for example, a photoconductor, and then selectively irradiating it with light in accordance with an image signal.
It is created by extinguishing the electric charge at the location where the light is irradiated. Alternatively, it can be made by charging a dielectric material such as paper or plastic film in response to an electrical signal using an electrostatic electrode called a multi-stylus head. and,
In order to develop this electrostatic latent image, toner charged to the opposite polarity to the electrostatic latent image carrier (photoreceptor drum, dielectric film, etc.) having the electrostatic latent image is applied to a charged location on the photoreceptor. A method of electrostatic deposition and development is known.

As the developing method, a dry developing method using a dry toner and a wet developing method using a liquid toner are known. Dry toner usually consists of a finely divided powder. Therefore, there is a problem of environmental pollution when dry toner scatters.
The cartridge containing the dry toner must be of a sealed structure, and many developing devices currently have a structure in which the electrostatic latent image carrier and the developing section are replaced. For this reason, the cost is high, but dry toner has the advantage of excellent storage stability and ease of handling if the cartridge method is adopted.

On the other hand, liquid toner is made by dispersing colorant particles such as pigments in an insulating liquid, and a developing electrode is used to charge the liquid toner from inside a toner container to a polarity opposite to that of the electrostatic latent image carrier using a centrifugal pump or the like. A developing device is known that has a structure in which colorant particles are ejected from a slit to electrostatically adhere to an electrostatic latent image carrier. However, in this developing device, excess liquid that does not adhere to the electrostatic latent image carrier returns to the toner container, and the concentration of colorant particles in the toner decreases. Therefore, concentration management of the developer (liquid toner) has been a problem. In addition, there have been various problems such as contamination due to liquid leakage during development, holding the developing device, or when replacing the liquid toner, and poor storage stability of the liquid toner due to coagulation and precipitation of colorant particles in the liquid toner. On the other hand, the electrostatic process using liquid toner has the potential to increase the resolution and gradation of images to a level comparable to that of silver-halide photography. It is expected to be a suitable electrostatic latent image development method.

Against this background, the present applicant previously filed a patent application in 1986-1.
In No. 56847, an electrostatic process that takes advantage of the advantages of the electrostatic process using liquid toner while solving various problems such as the difficulty of handling liquid toner, especially its easy staining, difficulty in maintenance, and poor storage stability, was proposed. A method for developing latent images was proposed. That is, the method is characterized in that a developer (toner) in which a coloring agent is dispersed in an electrostatically insulating organic substance that is solid at room temperature is heated to liquefy, and an electrostatic latent image is wet-developed using the liquefied developer. This is an electrostatic latent image method.

[Problem to be solved by the invention]

However, even in the technology proposed in Japanese Patent Application No. 63-156847, the developing device shown in the examples is solid until the solidified toner is put into the developing tank;
The problem that the toner concentration gradually becomes thinner during development, as with conventional liquid toners, has not been solved.

The present invention was proposed in view of the above circumstances, and employs a wet development method suitable for developing high-quality images such as resolution and gradation, while using conventional liquid or liquefied toner. To provide an electrostatic latent image developing method that solves various problems associated with the electrostatic latent image developing method, and in particular, can keep constant the amount of toner supplied to the developing process and the toner concentration (coloring concentration in the developer). The purpose is to

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention uses, as a developer, a solidified toner in which a colorant is dispersed in an electrically insulating organic substance that is solid at room temperature and liquefies upon heating, and uses the solidified toner as an electrostatic latent image. The method is characterized in that the toner is brought into heated contact with the electrostatic latent image carrier on which the solidified toner is formed, and development is carried out while the solidified toner and the electrostatic latent image carrier are moved relative to each other.

Furthermore, the present invention uses, as a developer, a solidified toner in which a coloring agent is dispersed in an electrically insulating organic material that is solid at room temperature and liquefies when heated, and the solidified toner is cut into flakes. This method is characterized by supplying solidified toner onto an electrostatic latent image carrier and performing development while heating it.

[Effect]

In the present invention, the solidified toner is brought into direct contact with a relatively moving electrostatic latent image carrier, sequentially melted by heating, and subjected to a developing process.

Therefore, the liquefied toner used for development is kept at a substantially fixed amount and is always fresh, and the concentration of the colorant etc. dispersed in the solidified toner is maintained at the initially set value. , toner density does not become thinner during development.

The same applies to the case where the solidified toner is cut into flakes and the flakes of solidified toner are supplied onto the electrostatic latent image carrier.

Therefore, the amount of solidified toner supplied during development can be easily controlled, and stable image formation can be performed.

〔Example〕

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

First, the present invention is based on the use of solidified toner as a developer, and this solidified toner will be explained.

The developer used in the present invention is a solidified toner in which colorant particles are dispersed in an electrically insulating organic material that is solid at room temperature.

Examples of electrically insulating organic substances that are solid at room temperature include paraffins, waxes, and mixtures thereof. Paraffins include normal paraffins having 19 to 60 carbon atoms, ranging from nonadecane to hexaconcune. Examples of waxes include vegetable waxes such as carnauba wax and cotton wax, animal waxes such as beeswax, osichelite, and petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum. These materials have a specific MM ratio ε at 20°C
is about 1.9 to 2.3. In addition to the above dielectric materials, polyethylene, polyacrylamide, poly-n
- A crystalline polymer having a long alkyl group in a side chain such as stearyl acrylate or a polyacrylate homopolymer or copolymer can be used.

Further, as the coloring agent dispersed in the electrically insulating organic material, conventionally known inorganic pigments, organic pigments, dyes, and mixtures thereof can be used. For example, as an inorganic pigment,
Examples include chromium pigments, cadmium pigments, iron pigments, cobalt pigments, ultramarine blue, and navy blue. In addition, organic pigments and dyes include Hansa Yellow (C, 1, 1, 1680
), Benzidine Yellow G (C, 1, 21090)
, Hengejin Orange (C, 1, 21110), Fast Trend (C, 1, 37085), Furilliant Carmine 3 B (C, 1, 16015-Lake),
Phthalocyanine Blue (C, [74160), Victoria Blue (C, 1, 42595-Lake), Spirit Black (C, 1, 50415), Oil Blue (C
, 1,74350), alkali blue (C, 1,42
770^), First Scarlet (C.

1.12315), rhodamine 6 B (C,1,4
5160), rhodamine lake (C, 1, 45160)
-Lake), First Sky Blue (C, 1, 7
4200-Lake), nigrosine (C01,504
1,5), carbon black, etc. These can be used alone or as a mixture of two or more, and those having the desired color development may be selected and used.

In addition to the above-mentioned electrically insulating organic substances and colorants, the solidified toner also contains additives for the purpose of improving dispersibility by entangling the colorant particles and at the same time making it easier to incorporate the charge donor described later to improve the amount of charge. In order to improve the fixation of the colorant, a resin may be used in combination. As such resin, known materials can be selected and used as appropriate; examples include butadiene rubber,
Styrene-butadiene rubber monocyclic rubber, rubbers such as natural rubber, styrene resins, vinyltoluene resins, acrylic resins, methacrylic resins, polyester resins, polycarbonate resins, polyvinyl acetate resins and other synthetic resins, Examples include rosin resins, hydrogenated rosin resins, alkyd resins containing modified alkyds such as linseed oil modified alkyd resins, and natural resins such as polyterpenes. In addition, phenolic resins, modified phenolic resins such as phenol-formalin resin, pentaerythritol phthalate, coumaron-indene resins, ester gum resins, vegetable oil polyamide resins, etc. are also useful, and polyvinyl chloride, chlorinated Halogenated hydrocarbon polymers such as polypropylene, synthetic rubbers such as vinyltoluene-butadiene, butadiene-isoprene, long-chain alkyl groups such as 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, lauryl acrylate, octyl acrylate, etc. or copolymers of these and other polymerizable monomers (for example, styrene-lauryl methacrylate copolymer, acrylic acid-lauryl methacrylate copolymer, etc.), polyolefins such as polyethylene, Polyterpenes etc. can also be used.

Further, a charge donating agent is usually added to the solidified toner, and the solidified toner used here is no exception. The charge-donating agents used are, for example, metal salts of fatty acids such as naphthenic acid, octenoic acid-oleic acid, stearic acid, isostearic acid or lauric acid, metal salts of sulfosuccinic acid esters, oil-soluble metal sulfonic acid salts, and phosphoric acid. These include ester metal salts, abietic acid metal salts, aromatic carboxylic acid metal salts, aromatic sulfonic acid metal salts, and the like.

In addition, in order to enhance the electrical charge of the colorant particles, Si
n,, AI! , 10s, T i OH, ZnO, Gag
Os, I nz03. Ge01. SnO2, Pbox.

Fine particles of metal oxide such as MgO or a mixture thereof may be added as a charge enhancer.

Regarding the blending ratio of each component mentioned above, the coloring agent is 0.01 to 100 g with respect to the molten state 11 of the electrically insulating organic substance,
It is common to set it as 0.1-10g.

However, in order to efficiently develop an electrostatic latent image with a small amount of developer, the concentration relative to the electrically insulating organic material [the ratio of the electrically insulating organic material to the colorant (dilution ratio)] must be 22 to 10% by weight. It is desirable that the range be within the range of .

This makes it possible to form high-quality images without uneven development, and also reduces the amount of waste toner.

The resin is added in an amount equal to or less than the amount of the colorant,
0.01 for the liquefied molten state Il of electrically insulating organic matter
It is preferable that it is ~100g, more preferably O,
i~log.

Also, the charge donor is usually 0.001 for the same <142.
-10g, preferably 0.01-1g. Furthermore, the charge enhancer is added in an amount of at most twice the weight of the colorant, preferably at most the same amount.

In the solidified toner described above, the charge amount of the colorant particles is l
X 10-' to 15XlO-' coulombs/g, and the excess ion concentration in the solidified toner is lXl0-7 to 3X1
It is preferable to set it as 0-' coulomb/d.

This is done in consideration of development characteristics; for example, if the charge amount of the colorant particles is smaller than 1X10-' coulombs/g, toner flow or staining of the image will occur; If it exceeds this, sufficient developed density cannot be obtained. Furthermore, if the excess ion concentration is less than 1 x 101 coulombs/d, the image will be sharp and 3 x 10-7 coulombs/d.
Exceeding d may cause toner flow, insufficient density, etc.

The amount of discharging of the colorant can be adjusted by selecting the type and amount of the resin, charge donor, and charge enhancer, and the excess ion concentration can be adjusted by selecting the type and amount of the resin, charge donor, and charge enhancer. It can be adjusted by adding lithium, sodium dioctyl sulfosuccinate, potassium dioctyl sulfosuccinate, etc.).

The above-mentioned solidified toner is brought into a heated and molten state during development, and the heating temperature at that time may be appropriately set depending on the melting point of the electrically insulating organic material, etc., and is usually 30 to 130°C, more preferably 40 to 110°C. It is assumed to be °C.

In the present invention, the solidified toner described above is used to develop an electrostatic latent image formed on an electrostatic latent image carrier such as a photoconductor. As shown, the solidified toner (1) is formed into a rectangular parallelepiped, and this is heated on a photoreceptor (or a photoreceptor with a printing sheet closely attached to the surface) which is heated in advance by a heater (2). (3)
Developing is carried out while pressing and contacting with the spring (4).

That is, the photoreceptor (3), which has been uniformly charged by the charger (5) and selectively exposed by the semiconductor laser (6) to form an electrostatic latent image, is moved in the direction of the arrow in the figure, and the electrostatic latent image is formed on the photoreceptor (3). A rectangular parallelepiped solidified toner (1) is brought into contact with a photoreceptor (3) on which a latent image is formed. At this time, the photoreceptor (3) is heated in advance by the heater (2) to a temperature higher than the melting point of the solidified toner (1). Further, a counter electrode (7) is disposed adjacent to the solidified toner (1) on the downstream side in the traveling direction of the photoreceptor (3).

Then, the solidified toner (1) is heated by the heater (2) provided on the photoreceptor (3), and the vicinity of the contact surface is melted. Then, this melted toner (1a) spreads between the photoreceptor (3) and the counter electrode (7) in the gap (usually 0.
1 to lam), electrophoresis of the colorant particles occurs between the photoreceptor (3) and the counter electrode (7), and the electrostatic latent image on the photoreceptor (3) is developed.

At this time, since the solidified toner (1) is pressed against the photoreceptor (3) by the spring (4), it is melted one after another as the development progresses, and is interposed between the photoreceptor (3) and the counter electrode (7). is supplied, and the amount is kept almost constant.

Note that the shape of the solidified toner (1) is not limited to the rectangular parallelepiped, and may be of any shape, such as a cylindrical shape, as long as it can maintain good pressure contact with the photoreceptor (3). In this example, the plate is shaped like a flat plate, but it may also be shaped like a drum, for example.

Furthermore, in this example, the photoconductor (3) is moved relative to the stationary solidified toner (1), but conversely, the solidified toner (3) is moved relative to the stationary photoconductor (3). 1)
Alternatively, the vehicle may be moved relatively by running the vehicle.

In Fig. 2, instead of providing a heater (2) on the photoconductor (3), a nozzle (8) that blows out hot air is provided near the solidified toner (1), and the hot air blown from the nozzle nozzle 8) solidifies the toner. The toner (1) is melted. Therefore, the temperature of the hot air blown out from the nozzle (8) is
It is necessary to set the temperature to at least enough to melt the solidified toner (1).

In this case, as in the previous embodiment, the developing process is carried out while melting the solidified toner (1) near the contact surface, that is, the photoreceptor (
3) and the counter electrode (7), and there is no need to embed the heater (2) in the photoreceptor (3).

Further, the hot air emitted from the nozzle (8) is not only used to directly melt the solidified toner (1), but also can be used to preheat the photoreceptor (3) to be transferred to the developing section. This can prevent the toner from cooling and solidifying during development.

When developing the electrostatic latent image on the photoreceptor (3) using the method described above, a small amount of developer remains on the developing surface in the form of a liquid film or droplets after development, and if left as is, it will remain in the remaining developer. The coloring agent may cause problems such as background smearing and fogging, and in the case of multicolor development, color mixing with the next developer.

Therefore, as shown in FIG. 3, a nozzle (9) for blowing out hot air is also provided on the exit side of the photoreceptor (3), and the remaining solidified toner (1b) is removed from the area other than the developing area (in this example, It is preferable to remove the particles by blowing them toward the bottom (in the figure) (so-called squeeze).

When squeezing, the temperature of the hot air blown from the nozzle (9) must be higher than the melting point of the solid toner (1) in order to keep it in a liquefied state, and the upper limit of the temperature is the boiling point of the solid toner (1). Although it must be as follows, it is also necessary to set it so that it does not adversely affect the characteristics of the photoreceptor (3).

Does squeezing out excess developer as described above eliminate background smearing, fogging, etc.? Although R color and the like are prevented, the colorant (image) developed into the electrostatic latent image is not affected at all at this time.

On each side described above, the solid toner is brought into direct contact with the photoreceptor for development, but as shown in FIG.
11) and the solidified toner (12) are placed facing each other and separated from each other,
The solidified toner (12) may be supplied onto the photoreceptor (11) while being cut.

In this example, a counter electrode (14) having a cutting blade (13) is used.
) moves relative to the solidified toner (12), and the blade (
13), the solidified toner (12) is cut into flakes and supplied between the counter electrode (14) and the photoreceptor (11). And this counter electrode (
14) and the photoconductor (11).
) is heated and liquefied by a heater (16) provided on a support (15) that holds a photoreceptor (11), and development is performed with this molten solidified toner (12a).

When one development is completed, the solidified toner (12) is moved by a spring (17) in a fixed amount of steps [the amount of flaky solidified toner supplied is controlled by this step amount. ] is sent out toward the photoreceptor (11), and the next development is carried out.

Note that the heat source is not only provided in the heater (15) provided on the photoreceptor (11), but also provided, for example, at the tip or middle of the cutting blade (13), or even at the counter electrode (14). Especially when there is a heat source at the tip of the cutting blade (13), there is an advantage that the torque needed to move the cutting blade (13) is small.

The above method also makes it possible to stably control the amount of solidified toner (12) per batch.

By the way, in each of the embodiments described above, since the solidified toner is supplied one after another, management of the solidified toner becomes a problem. For example, it is troublesome to replenish new toner or replace waste toner containers.

Therefore, as shown in FIG. 5, a toner container (18) containing the solidified toner (12) and a waste toner container (I9)
It is also possible to integrate the 5th toner and the 5th toner adjacent to each other so that the replenishment of new toner and the replacement of the waste toner container can be performed at the same time.
In the figure, the same components as in the example shown in FIG. 4 are given the same reference numerals, and the explanation thereof will be omitted. Further, in this example, the heater (16) is provided on the counter electrode (14).

With this configuration, the solidified toner (12b) used for developing the electrostatic latent image on the photoreceptor (11) is directly discarded into the waste toner container (19).

Here, the amount of solidified toner (12) stored in the toner container (18) and the amount of solidified toner (12b) discarded into the waste toner container (19) are approximately equal (or the latter is slightly smaller). At the same time as the solidified toner (12) is finished, the waste toner container (19) becomes full of used toner. Therefore, it is sufficient to simply discard the toner upon completion of development, thereby simplifying the troublesome toner replenishment work and toner disposal work.

In particular, as shown in FIGS. 6 and 7, solidified toners (31) and (32) of yellow magenta and cyan colors are used.
(33) are accommodated in the toner container section (34), (3
5) , (36) and the corresponding waste toner containers (37), (38), (39) are integrated in series or in parallel to facilitate toner exchange for forming color images. Work can be done all at once.

Note that if a display window is provided on the toner container or waste toner container, the remaining amount can be confirmed, further improving work efficiency.

Although the embodiments to which the present invention is applied have been described above, the present invention is not limited to these embodiments. For example, the photoreceptor and solidified toner may be arranged upside down.

Further, the electrostatic latent image carrier is not limited to a photoconductor, but may be a dielectric material or the like on which an electrostatic latent image is formed on selected droplets using a charging needle or the like.

〔Effect of the invention〕

As is clear from the above explanation, in the present invention, the solidified toner is brought into direct contact with the photoconductor and melted, or is scraped off into a thin plate shape and supplied onto the photoconductor, so the amount of toner supplied is can be kept approximately constant, the toner density can be kept constant, and stable image formation is possible.

Further, according to the present invention, the configuration of the developing device can be greatly simplified, which has a great effect.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing an embodiment in which solidified toner is developed while being brought into contact with a photoreceptor, and FIG. 2 is a schematic side view showing another embodiment in which development is performed while bringing solidified toner into contact with a photoreceptor. FIG. 3 is a side view schematically showing still another embodiment in which solidified toner is developed while being brought into contact with a photoreceptor. FIG. 4 is a side view schematically showing an embodiment in which solidified toner is supplied in the form of flakes. FIG. 5 is a schematic sectional view schematically showing an embodiment in which a waste toner container is integrally provided. 6 and 7 are schematic perspective views showing an example of a toner package in which a toner container section and a waste toner container section for color image formation are integrated, respectively. 1.12 ... Solidified toner 3.11 ... Photoreceptor

Claims (2)

[Claims] (1) A solidified toner made by dispersing a colorant in an electrically insulating organic material that is solid at room temperature and liquefies when heated is used as a developer, and the solidified toner is applied to an electrostatic latent image carrier on which an electrostatic latent image is formed. An electrostatic latent image developing method characterized by carrying out development while bringing the solidified toner and electrostatic latent image carrier into heating contact with each other and moving them relative to each other. (2) Using as a developer a solidified toner in which a colorant is dispersed in an electrically insulating organic substance that is solid at room temperature and liquefies upon heating, cutting the solidified toner into flakes, and solidifying the flakes. An electrostatic latent image developing method characterized by supplying toner onto an electrostatic latent image carrier and performing development while heating it.