JPS63116171A - Electrostatic recording system - Google Patents

Abstract

PURPOSE:To obtain a small-sized inexpensive printer by using an electrostatic recording body provided with a switching element, which is set to a high conductive state by a high electric field and is kept in this state, and an electric charge transport layer or a photoconductive layer on a conductive supporting body. CONSTITUTION:A switching element layer 3 which is set to a high conductive state by a high electric field and is kept in this state, an electric charge transport layer or a photoconductive layer 2, and a surface protective layer 4 are provided on a conductive supporting body 1. A potential higher than Vth is induced in the switching element layer by a high corona potential as shown in a figure A to set the whole of this layer to a high conductive state. For example, a thermal head 5 is used to apply heat in accordance with a signal as shown in a figure B. The switching element layer 3 is restored to a low conductive state by heating. Next, the switching element layer 3 is electrified again with a surface potential lower than Vth. At this time, only parts of the switching element layer 3 restored to the low conductive state are electrified with a high potential but the potential of the other parts is low to form a latent image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrostatic recording method using electrophotography, and is used in printers, facsimile machines, and the like.

BACKGROUND OF THE INVENTION The main recording techniques used in printers and facsimiles include thermal recording and electrophotography.

For the latter, optical printers using LED arrays, semiconductor lasers, and electrostatic recording methods have been put into practical use.

The former thermal recording method is compact, easy to maintain, and inexpensive, but has the problem of storage stability of recorded images. On the other hand, although the latter electrophotographic method has excellent preservation of recorded images, the equipment is large and expensive.

Among electrophotographic methods, optical printers are used for high-speed facsimiles and printers because they are fast and provide high image quality. However, since it requires expensive parts such as an LED array as a recording light source, a semiconductor laser, and a scanning polygon mirror, the device is also expensive and requires a lot of maintenance to maintain reliability.

For this reason, there is a strong demand for a recording method that has a simpler process, is more compact, and is less expensive.

Problems that the invention aims to solve Compared to optical printers, the electrostatic recording method has a simpler process, is smaller, easier to maintain, and is cheaper, but on the other hand, it requires a drive circuit for each recording electrode for recording. Moreover, since the recording voltage is high, it has been difficult to miniaturize the drive circuit.

An object of the present invention is to propose a compact and inexpensive electrostatic recording method that can solve these drawbacks.

Means to solve the problem A conductive support is brought into a highly conductive state in a high electric field and is a technical college?
using an electrostatic recording body comprising a switching element layer that maintains the state of conductivity and at least a charge transport layer or a photoconductive layer,
a step of applying a high electric field to the switching element to bring it into a highly conductive state; a step of locally canceling the high conductive state by heating to form a two-dimensional image;
forming latent images with different charge densities from the dimensional images.

Function: It has a small size and simple structure, and since recording is performed by heating, it does not require a high recording voltage unlike the electrostatic recording method.

EXAMPLE As shown in FIG. 2, a charge transfer layer 2, a switching element layer 3, and a surface protection layer 4 are formed on a conductive support 1 to prepare a recording medium.

Here, the capacitance of each layer is calculated as charge transfer layer: 01
, switching element layer: 02, and surface protection layer 203.

By subjecting this recording medium to corona charging treatment,
A potential is applied that is inversely proportional to the capacitance of each layer.

As shown in FIG. 3, the switching element layer transitions from a low conductivity state (I) to a high conductivity state (II) if it is in a strong electric field convergence (the potential applied to the switching layer is equal to or higher than vth).

The specific resistance of the layer in the low conductivity state is 1011 to 1014 Ω・e
m, and the specific resistance in a high conductive state is preferably 108 to 109 Ω·cm.

At this time, the ratio of specific resistance is 10 3 to 10 6 Ω·em, and excellent contrast can be obtained.

As shown in FIG. 1(A), a potential higher than vth is induced in the switching layer by a high corona potential, and the entire layer is brought into a highly conductive state. Next, as shown in FIG. 3B, heat is applied according to the signal using, for example, a thermal head. The switching layer returns to a low conductivity state by heating, and then the switching layer is charged again at a surface potential of vth or less.

At this time, only the portion where the switching layer has returned to the low conductivity state is charged to a high potential, and the remaining potential is low, forming a latent image.

This latent image is developed using a normal two-component development method or a one-component development method.

Potember et al., Journal of American Society (J.

Amer, Soc, ) Vol. 102, p. 3659 (1980
), or synthetic metals (Synth
etlc Metals) Volume 4, page 371 (1982
), a Cu-TCNQ (7,7,8,8-tetracyanoquinodi8meethane) charge transfer complex crystal thin film switched from a low conductivity state to a high conductivity 8 state at an electric field strength of about 104 V/cm. They found that this phenomenon occurs and reported the possibility of developing new applications as an organic memory material.

As a switching element, tetracyanoethylene (T
CNE), tetracyafushi9methane (TCN Q)
, 2,3,5.6-tetrafluoro7,7.8.8-
A complex of copper or silver with an electron-accepting substance such as tetracyafushi-8-methane (TCNQF4) is used, but other switching elements with similar properties can be used.

The above complex can be used directly as a crystalline or polycrystalline thin film by means such as vapor deposition, but it is also possible to use a charge transfer layer formed on a conductive support by dispersing a microcrystalline complex in a binder. It can be provided in As the binder, electrically insulating resins such as polyester resins, acrylic resins, styrene resins, polycarbonate resins, epoxy resins, silicone resins, and alkyd resins are used. At this time, the mixing ratio of the resin and the microcrystalline complex is adjusted so that the specific resistance of the low conductivity state is 1011 to 1014 Ω·cm.

For the charge transfer layer, a material with excellent injection efficiency of electrons from the above-mentioned switching element layer is selected.

Suitable materials include amorphous carbon (hereinafter referred to as a-C:
Amorphous silicon (hereinafter referred to as a-5l:H), a compound of amorphous silicon, carbon, nitrogen, and oxygen (hereinafter referred to as a SI C%a SI 1-XNXsl)
-x
7-dolinitro 9-fluorenone, 2.4.5.7-
Tetranitro-9-fluorenone, 2-nitrobenz8
thiophene, 2,4.8-)linitrothioxanthone,
Poly-N-H8
The complex with Nilcal A" Sol 8-ol is applied directly, or the mixture is dispersed in a solution of resin paint and applied to form a charge transport layer.

The surface protective layer is made of a-C:Hla-S, which has excellent heat resistance.
I C,a-S 1l-XNX%a-311-.

1-x x An amorphous inorganic compound containing O or the like as a main component is suitable.

In the electrostatic recording medium used in the present invention, the thickness of the switching element layer is 0.5 to 5 μm, preferably 1 to 3 μm, and the thickness of the charge transfer layer is 5 to 50 μm, preferably 10 to 25 μm.
m, the thickness of the surface protective layer is 0.01 to 1 μm, preferably 0
．． A thickness of 1 to 0.3 μm is desirable.

Further, an intermediate layer may be provided between the conductive support and the charge transfer layer for the purpose of blocking charge injection or improving the adhesion to the conductive support.

As the intermediate layer, for the above purpose, Al2O3, BaO1B
aOBe01Bi203, Cab, Ce2ゝ02゛002°3% L a 2°3' Dy2. '3
' Lu2°3゛Cr2O3, Cub, Cu2O, Fe
d, PbO.

MgO5SrO1Ta203, ThO2, Z r O2
, HfO2, TlO2, TIO, 5102, G e 0
2. Metal oxides such as 510% Ge01, T I N ,
Metal nitrides such as A IN% SnN, NbN% TaN, GaN, metal carbides such as WC, SnC, T Ic, etc.
Insulators such as S Ic, S IN, GeC, GeN, BC, BN, or polyethylene, polycarbonate,
Organic compounds such as polyurethane, polyparaxylene, silicone resin, and polyimide are used.

The printing means requires heating means to return the high conductivity state to the low conductivity state. The heating temperature is 50~
The temperature is 150° C., and a thermal head 5 as shown in FIG. 3 can be used, but printing can also be performed by heating with a laser beam or the like.

When a plasma CVD method is used as a means to form an amorphous inorganic compound that is a charge transfer layer, CH4°C2H4''C2H6 is used as a raw material gas to form a-C:H.
°C2H2゛C3H8? Gases such as C6H6゛ can be used, and a S l 1-XCX-a-5I
N, or form a S l □−x OX−
In the case of x x, SIH512H6, 513H8, S14ゝF 5ICI 5IHF 5IH2F2,
S14ゝ 4ゝ 3ゝH
F, 5IHCI 5IHCI 5IH3C13
A plasma CVD method using a raw material gas of 51 atoms such as 3'22'' is used.

Alternatively, a reactive sputtering method using polycrystalline silicon as a target in a mixed gas of Ar and H (F2 or C12 may also be mixed) is used.

Also, a SI 1-yCy (”'X)
(0<y<1), a S l □−yOy(
"H: X) (0<y<1), or a S
l 1-, Ny ('H'X) (0< y
<1) In addition, CH4, C
2H6, C3H8, C4H10"2H4"3H6"4H
Hydrocarbons such as 8"2H2"3H4'CHCH, CH3F
, , CH346'66ゝCI, CH1%C2H5C11C2H5Br1, etc., allyl halides, CClF3. CF4, CHF3゜C2F
Freon gas such as 6,03F8, Ca H6m F m (
A raw material gas of C atoms such as fluorinated benzene (m=1 to 6) is used by mixing it with a silicon raw material gas used in the plasma CVD method. Alternatively, in the reactive sputtering method, it is used in combination with a sputtering gas such as Ar. In addition, as an oxygen source, OCo
, Co2. No, N2' 0, etc., and as a nitrogen source, a mixture of N2, NH3, NO, etc. is used. Alternatively, conductivity can be controlled by adding impurities to these films to obtain desired charge transfer characteristics. Examples of p-type impurities that provide p-type conductivity include B, AI, Ga, and In, which belong to group m of the periodic table.
B+AI, Ga are preferably used, and as n-type impurities that provide n-type conductivity, there are N, P, As%sb, etc. belonging to Group Ⅰ of the periodic table, and P is preferably used. .

As is used. P, As to improve electronic conductivity
is suitable.

In the case of n-type impurities, N N H3, N0%N20.
2ゝNOPHPHPHHI%PF3, PF5.2ゝ 3'2
4ゝ 4 PCI PCI PBr3. PBr3, PI3
．． 3'5' A s HA s FA s CI A s
B r 3, sb3ゝ 3'3' HSbF SBF 5bCI3.5bC153
Gases such as ゝ 3ゝ 5ゝ, or these gases'i: H2HHe
In the plasma CVD method, gas diluted with sAr is used to form the above C atoms, 5
1! It may be used by mixing with a raw material gas such as carbon, or in the case of reactive sputtering, it may be used by mixing with a sputtering gas such as Ar.

Examples will be described below.

Example 1 An aluminum drum was made with a length of 45 cm and an inner diameter of 116 cm.
Arranged in a capacitively coupled plasma CVD apparatus with a cylindrical discharge electrode of mφ in 9 reaction vessels @ 5 x 1O-
After evacuation to 6 Torr or less, the aluminum drum substrate holder was heated to 250 N200°C - 35 C2H2
Introducing 0-600scam and increasing the pressure to 0.2-1,0
After adjusting to Torr, a 15 to 20 μm thick a-C:H layer was formed using high frequency power of 100 to 250 W.

Thereafter, a switching element layer was formed by taking it out once and following the steps below.

5 parts by weight of Cu-tetracyanoquinodimethane (Cu-TCNQ) complex pulverized by a ball mill was mixed with a solution consisting of 10 parts by weight of polyacrylate resin, 0.5 parts by weight of polyethylene glycol, and 90 parts by weight of chloroform. After 20 minutes of ultrasonic dispersion, it was applied and dried. The film thickness was 1.5 μm.

Furthermore, 5IH4 was heated at 10 to 30 sC using the above CVD equipment.
CIl, C2H4 was introduced for 20 to 40 sec, and the pressure was 0.
．． S at 2-1.0 TOrr + high frequency power 50-150W
I1-XCX''H (0<x<1) as a surface coating layer at a substrate heating temperature of 100 to 150°C and a heating temperature of 0.28 to 0.
A thickness of 3 μm was formed to prepare an electrostatic recording medium.

The electrostatic recording medium thus obtained was charged using a corotron charger at a corona potential such that aC:H alone had a potential of -1000V. At this time, a potential of 2 V or more was applied to the switching element layer, and the layer transitioned to a highly conductive state, so in reality, only a residual potential of about -100 V was present.

Next, printing was performed using a thermal head. Thereafter, charging treatment was performed again using the Scorotron charger at a corona potential such that the surface potential was 1600V. Only the locations that had been returned to a low conductivity state by the thermal head were charged to a potential of -600V.

The electrostatic recording medium in this state was developed using a two-component developing device, transferred to recording paper, and then heat-fixed.

Thereafter, after AC static elimination and cleaning, the above process was repeated again. Even in such repeated use,
There is very little change in residual potential, and there are no scratches.
Can withstand use of over 80,000 sheets.

Example 2 Polyvinylcarbazole 1 as a switching element layer
PV with 90 parts by weight of tetrahydrofuran added to 0 parts by weight
A PVK-TNF complex solution prepared by adding 1 part by weight of 2,4,5.7-tetranitro-9-fluorenone to a K solution was sufficiently dissolved using an ultrasonic disperser, and then a dried film was placed on an aluminum drum substrate. It was applied to a thickness of 20 μm and dried.

Next, as in Example 1, the switching element layer was formed to a thickness of 2 μm.
Formed.

As a surface protective layer, a hard carbon layer having a thickness of 0.1 μm was formed using a reactive sputtering method to prepare an electrostatic recording medium.

The electrostatic recording medium thus obtained was charged using a corotron charger at a corona potential such that PVK-TNF alone had a potential of -800V. At this time,
Since a potential of 2 V or more was applied to the switching element layer and the layer transitioned to a highly conductive state, there was actually only a residual potential of about -200 V.

Next, printing is performed using a thermal head. Thereafter, charging treatment was performed again using a Scorotron charger at a corona potential such that the surface potential was 1,500 μm.

Only the locations that had returned to the low conductivity 8 state by the thermal head were charged to a potential of -500V.

The electrostatic recording medium in this state was developed using a two-component developing device, transferred to recording paper, and then heat-fixed.

Thereafter, after AC static elimination and cleaning, the above process was repeated again. Even in such repeated use,
Can withstand use of 80,000 sheets.

Effects of the Invention According to the present invention, there is provided an electrostatic recording material comprising, on a conductive support, a switching element layer that becomes highly conductive in a high electric field and maintains a highly conductive state, and at least a charge transport layer or a photoconductive layer. applying a high electric field to the switching element to bring it into a highly conductive state; locally canceling the high conductivity state by heating to form a two-dimensional image; and charging the switching element to form a two-dimensional image. By including the step of forming latent images having different charge densities from the above, it is possible to provide an electrostatic recording printer that is smaller and cheaper than ever before.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the recording process of an electrostatic recording method in an embodiment of the present invention, FIG. 2 is a cross-sectional view of an electrostatic recording medium in an embodiment of the present invention, and FIG. 3 is a graph showing the -I characteristics and switching phenomenon of the switching element layer. 1-m-support, 2-m-charge transfer layer, 3--switching element layer, 4-m-surface protection layer, 5-m-thermal head. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Using an electrostatic recording material having a switching element layer that becomes highly conductive and maintains a highly conductive state in a high electric field and at least a charge transport layer or a photoconductive layer on a conductive support, A step of applying a high electric field to create a highly conductive state, a step of locally canceling the high conductive state by heating to form a two-dimensional image, and a latent image with a different charge density from the two-dimensional image by charging treatment. An electrostatic recording method including a step of forming a. (2) The electrostatic recording method according to claim 1, characterized in that a thermal head is used as the heating means.