JPS58173766A - Developing method of electrophotograph - Google Patents

Abstract

PURPOSE:To improve the quality of a picture image formed by a wet developing system, by supplying insulating liquid to the toner release layer formed on a flexible support, and positioning a holding surface for an electrostatic latent image and the toner release layer so as to face each other apart at a slight spacing then separating both. CONSTITUTION:Since insulating liquid 30 is coated uniformly and thinly on the toner release layer 28 in the part contacting with a porous member 19, the binder in the layer 28 dissolves quickly. The toner is thus dispersed and the liquid film 31 of the developing soln. is formed. The surface of an electrostatic latent image contacts with the film 3 and forms a meniscus 41, where developing is effected. For example, when an electrostatic latent image 38 arrives at the meniscus, the negative-charged toner sticks thereon and forms a toner image 39. When a member 11 advances further and detaches from the meniscus, a dried toner image 40 is obtained and is then fixed. Since the developing soln. is formed just prior to the development in the above-mentioned way, there is no change in the toner density with the passage of time and the developing electrode is kept free from contamination. The quality of the picture image is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for developing electrostatic images obtained by electrophotography and electrostatic recording, and Section 41 relates to a wet developing method. In the present invention, the above electrophotographic method and electrostatic recording method are collectively referred to as electrophotographic method.

Microphotographic cameras using a wet development method for electrophotography are known today. For example, JP-A-50-144443
No. 53-133034, No. 50-83056,
and Japanese Patent Publication No. 49-33791, etc.

Since all of these prior art techniques use a developer, the following drawbacks are unavoidable.

■ If the toner is not used for a long period of time, the toner aggregates and precipitates, resulting in a change in toner meltability. Also, the resistance of the developer changes and therefore the photographic properties change over time.

■ Even if it does not last for a long time, if the amount of toner consumed is large, the toner pressure (inside) and liquid resistance will change, causing the problem of ■6. K or sometimes toner #11 degrees must be supplied with a very hot refill tank,
As a result, the device becomes complicated.

■ If the developer is left unused for a long period of time, the developer dries at the nozzle and rollers, and toner and resin contained in the solution get stuck, making maintenance difficult.

(2) Toner is electrodeposited on the head of the developing electrode, and cleaning and secondary cleaning is required.

■ A round pump is required to stir the developer and send waves, making it difficult to make the device more compact.

■ Since the exposed area of the flammable developer to the air is large, the amount of volatilization is large and there is a risk of fire. Therefore, it was necessary to actively exhaust the volatilized solvent vapor. As a result, solvent vapor may accumulate in the room.
Also, the developer evaporates rapidly.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and provide a developing method for electrophotography.

That is, the present invention provides a method for developing an electrostatic charge image formed on an electrostatic charge retaining member with toner dispersed in an insulating liquid, in which the toner is dispersed in the insulating liquid when it comes into contact with the insulating liquid. The toner releasing layer and/or the toner releasing layer of the toner holding material is provided on a flexible support.
The insulating liquid is supplied by bringing the insulating liquid into contact with a limited area of the surface of the electrostatic charge retaining member for X-rays, and then the electrostatic charge image retaining surface and the toner release layer are brought into contact with each other or maintained at a minute distance. This is an electrophotographic developing method characterized in that the two are separated after being made to face each other.

Further, one embodiment of the present invention is an electrophotographic developing method having the above structure, characterized in that an insulating casing is coated with the toner emitting layer Km. The electrophotographic developing method having the above-mentioned structure is characterized in that coating is applied to both the holding member and the toner release layer. An electrophotographic developing method having the above-mentioned structure is further characterized in that: between the conductive layer of the electrostatic image holding member and the conductive layer of the ()ner-segregation layer support; To,
The electrophotographic developing method having the above structure is characterized in that a bias voltage having a polarity that drives the toner toward the electrostatic image holding INK or spreads the toner is applied.

The present invention will be further described below using the drawings KIIMKm! I will clarify.

Figure J11 shows an embodiment of the present invention, in which 11 is an electrophotographic recording material, 10 is a supply roll thereof, and 12 is a stacking four. The electrophotographic recording material 11, as shown in FIG. 24 (thin vapor deposited metal film, tin oxide, indium oxide, iodized steel, and other known materials),
and a transparent photoconductive insulating layer 25 provided thereon (for example, many known organic photoconductive layers such as polyvinylcarbazole, other organic pigments, ZaO fine powder dispersed in a polymer binder, amorphous selenium vapor-deposited) 1 formed by a method, a layer formed by C and dB by sputtering, and other known materials), but in addition, known undercoat layers, intermediate layers, oat ζ-coat layers, etc. may also be designed. good. 16 is a known corona charger, 14 is a photographic lens, 16 is a toner discharge member, 15 is a supply roller thereof, and 17 is a 9-hole roller.

As shown in the cross section of FIG. 6, the toner emitting member 16 includes a support 26 (for example, paper, polyethylene terephthalate, polycarbonate, polyamide, polyethylene, acrylic resin, and many other plastic films) and a conductive layer 27 provided thereon. (similar to layer 24 but not necessarily continuous l/%), and a toner release layer 28 provided thereon. To show the toner release layer enlarged, J
Part 29 of Figure IIB is enlarged to Figure 114. The toner release layer consists of at least a rounded binder that fixes toner particles and wrinkle particles, and also contains various additives (for example, *1 binder, fixing agent, etc. to make the electrical properties uniform). It may also include the following. From the viewpoint of ease of dispersion, the toner particles are preferably fine particles (generally one particle or less) and uniformly charged. The toner-tooth member 16 is driven through the eyelet 22, and the moving mechanism Fi (not shown) 18 is an insulating casing supply tank and a porous member 19 (felt, string, cloth). is inserted to absorb the waves in the tank and form a thin layer Ki on both sides of the toner release layer.
K clothed. The insulating liquid supply device is operated by a drive mechanism (not shown): 1. The toner release layer is applied to the desired area by pulling it apart. A minute gap is formed between the p-ra 22 and the electrophotographic recording layer, and it is desirable that the speed and direction of the member 110 be the same to avoid smearing caused by toner rubbing on the recording layer, but this is not necessary. .

After the toner has adhered to the electrostatic charge image and development is completed, excess liquid is removed by a suitable method (for example, by air squeezing) (not shown), and then the toner is fixed (by a fixing device).

FIG. 1 shows an example of fixing using infrared rays, which consists of an infrared lamp 20 and its reflector 21, but there are other known methods such as pressure fixing and solvent fixing that coats a spray-like fixer. However, in heat fixing that directly utilizes a heat source, special care must be taken in terms of the mechanism since the developer is flammable. Furthermore, in the wet development method of the present invention, the fixing step can be omitted by only evaporating the carrier liquid as the insulating liquid. After drying and fixing, the electrophotographic recording material is wound onto a winding roll 12.

FIG. 5 shows an example of an insulating liquid supply device, which includes a tank 18, a porous member 19, and an insulating liquid 30.

If the thick part of the tank 18 is made thin and the porous member is held in this part, there is no fear that the chest will spill even if the device is tilted, and evaporation can be kept to a minimum.

FIG. 7 is an enlarged view showing how sixth expansion development is performed.

Since the toner release layer is coated with a uniform thin layer of insulating liquid on the part where the porous member 19 comes into contact, the binder in the toner release layer is quickly dissolved, the toner is dispersed, and the developer is uniformly distributed. A liquid film 61 is formed.

When the electrostatic charge surface comes into contact with this liquid JI31, the meniscus 41
is formed, and development is performed on the grain part. For example, when the electrostatic charge image 38 reaches the meniscus, negatively charged toner adheres to form a toner image 39. As the member 11 advances further and leaves the meniscus, it dries and a nine toner image 40 is obtained. This toner image is then fixed (for example, by second fixing with an infrared lamp), but fixing is possible even before it is necessarily dry.

As shown in the figure, switches S1 and S! If the switch S2 is opened and the switch 81 is closed, normal development is carried out, or if the switch 81 is closed, reverse development is carried out. In this case, when performing normal development, the drop polarity on the photoconductive insulating layer 25 may be selected to be opposite to the polarity of the toner, and when performing reversal development, this charging polarity may be selected to be the same as the polarity of the toner. Just choose the polarity. Further, as another method of performing both normal development and reversal development in the same device, for example, symbols 15, 16, 17, 18, 19 and 2 in FIG.
There is a method in which two developing means as shown in FIG. 2 are prepared and these two developing means are switched according to normal development and inversion. In this case, the above-mentioned switching of the polarity of the round band is essentially unnecessary, and it is only necessary to make the charging properties of the toner in each toner discharge member 16 different from each other. In this case as well, a bias voltage indicated by the symbol VK in FIG. 1116 is applied to the developing means for performing reversal development.

The present invention obviously does not suffer from the problems mentioned above because the developing fII solution is formed immediately before development. Also, since the new surface of the toner emitting layer always faces the user, there is no need to worry about the current electrode getting dirty. Furthermore, since KlAIIItK is supplied as a thin liquid film, drying is quick. Furthermore, if the row 222 is not pressed down to form a meniscus, and if the member 19 is kept away from the toner release layer, the toner will not be released even if the device is stopped.
You don't have to worry about it getting sticky.

The overlapping toner release layers in the present invention will be explained in more detail.

The toner release layer may simply be a composition formed by vapor deposition of a carrier liquid of a well-known developer. That is, the developer is made by dispersing carbon black and other organic or inorganic pigments in an organic solvent, and the carrier liquid is generally an insulating, odorless, non-toxic purified isoparaffin with a boiling point of 120 to 200C. type hydrocarbons are used. If cost is ignored, silicone oil, halogenated hydrocarbons, etc. can also be used. As mentioned above, the toner particles as pigments are fine particles and have uniform chargeability for ease of dispersion.In addition, rounded alkyl particles are used as additives in the carrier liquid to make the electrical properties uniform. Charge control agents and fixing agents such as resins, linseed oil, and metal soaps, as well as surfactants are used together.

4. Making the toner release layer. A conductive layer is provided on the support, and a coating liquid of an appropriate viscosity is coated and dried by adding the above-mentioned appropriate solvent to the well-known developer formula to reduce the solid content. Bye.

Finally, toner may be electrodeposited on the conductive layer using a known IA solution and dried.

It is desirable that the toner release layer composed in this manner has a certain degree of mechanical strength in a dry state, and for this purpose, a binder is required to bind the toner particles together.
This can be done by either or both of the above-mentioned dispersion stabilizer and charge moderation agent, but they may also be used separately. It is desirable that this binder dissolves quickly in the insulating liquid, otherwise the development rate at the meniscus will be low.

In this example, the toner release member is placed on the surface of the support! Using the vignetted photoconductive layer as a developing electrode, a toner charged to the opposite polarity is attached to the electrostatic charge image 38 formed on the electrostatic charge image holding surface to form a true image, and a toner charged to the same polarity is attached. A bias voltage is applied in a direction that drives the toner toward the electrostatic charge image holding area. By applying a low bias voltage (which has the same polarity as the charge image), a portion of the toner can be pulled away from the developing electrode, and it is also possible to obtain an image without fog. In any of the above-mentioned embodiments, a conductive layer is provided as a developing electrode and is effective for producing continuous tone medium-black images, but in another embodiment of the present invention,
The above conductive layer may not be provided.

71st! 1 indicates another embodiment of the present invention. 32 and 33
The insulating casing coating device 32 coats the toner release layer and 55 coats the casing on the electrostatic charge image 1 (Iiii). Each device can be moved in the direction of arrows 54 and 55 so that the Klkl canvas is placed where required on each surface. 56 and 37 show the areas where aS was applied (by applying Km to both the toner emitting layer and the electrostatic image bearing surface), the meniscus 42
It has the advantage that it is easily formed and the background of the screen is less likely to get dirty.

It is sufficient that the insulating liquid is applied to at least one of the toner release layer and the electrostatic charge retaining surface, but it is most desirable for the above-mentioned reason to apply the insulating liquid to both. is desirable. When applying an insulating liquid to the toner release layer, if the application is completed during exposure before the surface on which the electrostatic charge image is formed is being charged, there will be enough time for development to occur at the meniscus. This method has the advantage that toner release is sufficient and development can be carried out quickly.

As the insulating liquid, those used as carrier liquids of known developing solutions can be used, such as iso, v-H,
G, E (both manufactured by Etsuzo Standard Oil Co., Ltd.)
Product name), kerosene, decalin, toluene, gasoline,
Examples include insulating hydrocarbon liquids such as four-carbon and the like.

In another aspect of the present invention, the photoconductive layer of the electrophotographic recording material is formed into a rough surface to improve the liquid retention of the developing waves that come into contact with it. For example, in a recording material made of zinc oxide, fine powder of zinc oxide is mixed with a matting agent such as titanium dioxide or glass to form a rough surface of the photoconductive layer. Alternatively, the surface of the support of the recording material may be roughened in advance, and a conductive layer and a photoconductive layer may be uniformly formed thereon. When electrostatic charges are formed on the photoconductive layer affected by such a rough surface, the amount of coating liquid for the meniscus dissolved in the insulating liquid is sufficient (and therefore the image density is also increased).
Effects such as shortening the current time can be obtained.

According to a false embodiment of the present invention, an electrostatic recorder is used in an electrophotographic recording material, and a high voltage is applied to an electrode (such as a metal contact on a conductive layer) to generate electrostatic charges having various noturns or arrangements. It is also possible to use a so-called electrostatic recording method for imaging. Another method of the present invention is a method in which an electrophotographic recording material on which an electrostatic latent image is formed is transferred to a developed transfer medium (for example, plain paper) to obtain an image.

As mentioned above, since the present invention uses a toner with a fine grain size, which is an advantage of the wet development method, it is possible to obtain images with high resolution and rich in continuous gradation reproduction, and furthermore, the developing section is simpler than the dry method. It is a developing method that compensates for the significant drawbacks of the wet method in the field of fax copying, and is particularly suitable for microphotography. However, the present invention is not limited thereto, and can be applied generally to the purpose of obtaining high-quality images.

[Brief explanation of drawings]

Figure $1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a sectional view of the electrophotographic recording material used in the present invention. 6 and 4 are a cross-sectional view and an enlarged cross-sectional view of the toner discharge member used in the present invention. FIG. 5 is an explanatory diagram showing one embodiment of an insulating liquid supply mechanism. Figure IK6 is an enlarged view illustrating an embodiment of the present invention. FIG. 7 is a sectional view showing another embodiment according to the present invention. 11... Electrophotographic recording material 13... Cop charger 16... Toner discharge member 1B... Insulating housing supply tank 19... Porous member 22... Drive roller 26...・Support 27... Conductive layer 28... Toner layer 50... Insulating casing 32.55... Insulation Procedural amendment document 1982 Fuji Photo Film Co., Ltd. 1) Specification @ page 11, line 10, "evaporation" is corrected to "evaporation J." 91, page 12, line 2, "together" is replaced with "as necessary"
and correct it. In the second line of the same page, "toner ga" is corrected to "toner wo." 4) Delete "Gasoline" from the 4th line from the bottom of page 14.

Claims (5)

[Claims] (1) In a method of developing nine electrostatic charges formed on an electrostatic charge retaining member with toner dispersed in an insulating liquid, the toner is dispersed in the insulating liquid when it comes into contact with the insulating liquid. The insulating liquid is brought into contact with a limited area of the surface of the electrostatic charge retaining member and/or the toner discharge layer of the toner retaining material provided on a flexible support. An electrophotographic developing method characterized in that the insulating liquid is supplied, and then the electrostatic charge image holding surface and the toner emitting layer are brought into contact with each other or faced to each other while maintaining a small Fi interval, and then separated. (2) The electrophotographic developing method according to claim (1), characterized in that an insulating liquid is applied to the toner release layer. (3) Claim IJ characterized in that an insulating liquid is applied to both the electrostatic charge holding member and the toner release layer.
The electrophotographic developing method described in Section II(1). (4)) The electrophotographic developing method according to claim (1), wherein at least the surface of the support of the release layer is electrically conductive. (5) Between the conductive layer of the electrostatic charge position holding member and the conductive layer of the toner release layer support, apply an asumi pressure having a polarity that drives or attracts the toner toward the electrostatic holding box. An electrophotographic developing method according to claim (1), characterized in that: