JPH06332198A - Electrostatic charge recording medium imparted with charge transfer ability - Google Patents

Abstract

PURPOSE:To provide an electrostatic recording medium by which an information charge stored on an electrostatic charge holding layer is not affected by a disturbance factor such as humidity and contact. CONSTITUTION:This electrostatic charge recording medium having an electrostatic charge holding layer 10 at least on an electrode layer 13 is obtained by laminating a record charge transfer layer 12 consisting of a polymer obtained by bringing a polymer having a fluorine-containing aliphatic cyclic structure into contact with gaseous fluorine on a record charge holding layer 11 consisting of a polymer having the fluorine-containing aliphatic cyclic structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge recording medium capable of electrostatically recording information by an exposure method at the time of applying a voltage and reproducing the information at an arbitrary time, and in particular, it has excellent charge retention characteristics. The present invention also relates to an electrostatic charge recording medium having excellent disturbance resistance.

[0002]

2. Description of the Related Art A photoconductor in which an electrode layer and a photoconductive layer are sequentially laminated on a support, and an electrostatic charge recording medium in which an electrode layer and an electrostatic charge retention layer are sequentially laminated on a support are arranged to face each other. Japanese Patent Application Laid-Open No. 1-290336 discloses that an image is recorded as an electrostatic latent image on a charge holding layer by performing image exposure while applying a voltage between electrodes and reproducing the electrostatic latent image. ing.

According to this method, extremely high resolution analog recording is possible, and the electrostatic latent image recorded on the electrostatic charge recording medium is held semipermanently. The surface charge recorded on the surface tends to be gradually attenuated due to moisture in the air, etc.
There is a problem that the electrostatic latent image is destroyed by external damage or contact.

Therefore, an electrostatic charge recording medium in which an electrostatic latent image is formed on an electrostatic charge holding layer and then a protective layer is laminated on the surface to protect the electrostatic latent image is disclosed in Japanese Patent Laid-Open No. 203353/203. As another electrostatic charge recording medium, the electrostatic charge holding layer is patterned by laminating a photoconductive layer or a conductive layer on an insulating layer, and a thin insulating resin layer is further laminated on the pattern layer. The electrostatic latent image formed on the surface of the electrostatic charge retentive layer is made to pass through the thin film insulating resin layer by the tunneling phenomenon and accumulated in the photoconductive layer or the conductive layer to form the electrostatic latent image. An electrostatic charge recording medium to be held inside the electrostatic charge recording medium is disclosed in JP-A-2-244156.

Furthermore, as another electrostatic charge recording medium, an electrostatic charge recording layer is used in which the electrostatic charge retaining layer is a laminate of a resin layer having a low glass transition temperature and a heat resistant insulating layer, and an electrostatic latent layer is formed on the surface of the electrostatic charge retaining layer. JP-A-3-7943 discloses that an electrostatic latent image can be internally held by heating an electrostatic charge retaining layer at a temperature not lower than the glass transition temperature of a resin layer having a low glass transition temperature after recording an image. Has been done.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrostatic charge recording medium which is excellent in disturbance resistance such as moisture resistance and contact resistance and which does not disturb or attenuate recorded and accumulated information charges. .

[0007]

As a result of intensive studies, the inventors of the present invention have found that in an electrostatic charge recording medium having an electrostatic charge retaining layer on at least an electrode layer, the electrostatic charge retaining layer has a fluorine-containing alicyclic structure. Moisture resistance is improved by forming a recording charge transport layer made of a polymer obtained by contact-treating a polymer having a fluorine-containing alicyclic structure with a fluorine gas on the recording charge retention layer made of a polymer having It has been found that the electrostatic charge recording medium can be made into an electrostatic charge recording medium which is excellent in disturbance resistance such as resistance and contact resistance, and in which information charges recorded and accumulated are not disturbed or attenuated.

It has also been found that in the electrostatic recording medium of the present invention, the polymer having a fluorinated alicyclic structure is preferably a polymer having an alicyclic structure in its main chain.

The electrostatic recording medium of the present invention will be described below. 1A and 1B are cross-sectional views showing an example of each aspect of the electrostatic charge recording medium 3 of the present invention, in which 3 is an electrostatic charge recording medium, 10 is an electrostatic charge holding layer, and 11 is an electrostatic charge holding layer. A recording charge retention layer, 12 is a recording charge transport layer, 13 is an electrode, and 15 is a support.

The electrostatic charge retaining layer 10 is a recording charge retaining layer 11
First, the recording charge retention layer 11 is made of a polymer having a fluorine-containing alicyclic structure having high insulation (volume resistivity of 10 ¹⁴ or more) from the viewpoint of electrostatic charge retention characteristics. Preferably. Such a resin can be exemplified in a wide range including conventionally known or well known resins, but in the present invention, preferably,
A fluorine-containing polymer having a specific ring structure as shown below in the main chain can be used. For example,

[0011]

[Chemical 1]

(However, 1 is 0 to 5, m is 0 to 4, and n is 0.
-1, 1, 1 + m + n is 1-6, R is F or CF ₃ )

[0013]

[Chemical 2]

(However, o, p, q are 0 to 5, o + p + q
Is 1 to 6)

[0015]

[Chemical 3]

(Wherein R ₁ and R ₂ are F or CF ₃ ) having a ring structure. Of these,
Polymers having the following ring structures are typical. However, the contents of the present invention are not limited to these.

[0017]

[Chemical 4]

In the above, a polymer having a perfluoroaliphatic cyclic structure has been exemplified, but in the present invention, a part of the above exemplified fluorine atoms is substituted with another hydrogen atom or an organic group, or metathesis. Obtained by polymerization

[0019]

[Chemical 5]

Those having a ring structure such as The above-mentioned polymer having a fluorinated alicyclic structure is produced by using the fluorinated monomer disclosed in JP-A-4-189802 as a raw material and the production method also disclosed in the same. The polymer A produced in the examples of the publication is commercially available under the trade name "CYTOP" (standard) manufactured by Asahi Glass Co., Ltd., for example.

The polymer obtained by subjecting the above-mentioned polymer having a fluorine-containing alicyclic structure to a crosslinking treatment has solvent resistance when a recording charge transport layer, which will be described later, is laminated. It is preferable because it does not impair the charge transport property in the layer, and examples thereof include those commercially available under the trade name “CYTOP” (crosslinked type) manufactured by Asahi Glass Co., Ltd.

The recording charge retention layer is a 2% to 13% solution prepared by dissolving the above-mentioned fluoropolymer in a fluoro solvent such as perfluoro (2-butyltetrahydrofuran).
It may be formed by coating on an electrode having a support by spinner coating, dipping, blade coating, or the like. Alternatively, the above-mentioned fluorine-containing polymer may be formed into a film, and the film may be attached to the electrode with an adhesive.
When the fluoropolymer film itself has a supporting property, the electrodes may be laminated on the film by a method such as vapor deposition. The thickness of the recording charge retention layer after drying is 1 μm to 10 μm.
It is preferable to set m.

Next, the recording charge transport layer 12 will be described. Regarding the characteristics of the recording charge transport layer, when the recording charge transport layer is laminated on the electrode layer and the surface thereof is charged, charge transfer occurs in the layer width direction under room temperature conditions and has almost no charge storage ability. It has characteristics.

The recording charge transporting layer of the present invention comprises a polymer obtained by contacting the fluorine-containing alicyclic ring-forming polymer described in the recording charge retaining layer with fluorine gas. Those obtained by fluorinating the polymer A in the examples of JP-A-4-189802, such as those commercially available under the trade name "Cytop" (s-type) manufactured by Asahi Glass Co., Ltd. To be

Since the polymers treated in Comparative Example 1 and Comparative Example 2 of the above publication do not show such charge transporting property, the end groups of the polymers having a fluorine-containing alicyclic structure are treated with fluorine gas. It is presumed that it is inactivated by and the chargeability is deactivated.

The recording charge transport layer has a concentration of 2% by dissolving the above-mentioned polymer which has been contact-treated with fluorine gas in a fluorine-based solvent such as perfluoro (2-butyltetrahydrofuran).
It is advisable to form a 13% solution and apply it to the recording charge retention layer by spinner coating, dipping, blade coating or the like. The thickness of the recording charge transporting layer after drying may be 1 μm to 10 μm, preferably 1 μm to 5 μm. When it is less than 1 μm, the effect of lamination is insufficient. It is not preferable because it is disturbed by.

To form the recording charge transport layer, after stacking the recording charge retaining layer, the surface of the recording charge retaining layer is contact-treated with fluorine gas to change the surface layer of the recording charge retaining layer into the recording charge transporting layer. Good. The treatment method with fluorine gas is
It can be carried out by the method disclosed in JP-A-4-189802. At this time, in order to avoid reaction of fluorine gas with the electrode or the support on which the recording charge retention layer is laminated,
It is necessary to design and treat the device so that only the surface of the recording charge retention layer comes into contact with the fluorine gas. The treatment conditions with the fluorine gas may be appropriately set while experimentally confirming the function as the recording charge transport layer and the function as the recording charge retaining layer.

The material of the electrode 13 is not limited as long as its specific resistance value is 10 ⁶ Ω · cm or less. For example, it is an inorganic metal conductive film, an inorganic metal oxide conductive film, an organic conductive film such as a quaternary ammonium salt, etc., which is formed on a support by a method such as vapor deposition, sputtering, CVD, coating, plating, dipping, and electrolytic polymerization. To be done. Further, it may be formed on the support through an adhesive layer. The film thickness needs to be changed depending on the electrical characteristics of the material forming the electrodes and the applied voltage at the time of recording information. It is formed over the entire surface or in accordance with the formation pattern of the electrostatic charge retaining layer.

The support 15 in the electrostatic charge recording medium shown in FIG. 1B strongly supports the electrostatic charge recording medium 3, and has a strength sufficient to support the electrostatic charge retaining layer 10. If it has, the material and the thickness thereof are not particularly limited. For example, a rigid body such as a flexible plastic film, metal foil, paper, glass, plastic sheet, metal plate (which can also serve as an electrode) is used.

When the electrostatic recording medium has a flexible film, tape or disk shape, a flexible plastic film is used as a support, and when strength is required, a rigid sheet, glass, etc. Inorganic materials and the like are used. In addition, the electrostatic recording medium may also be required to have optical transparency. When light transmittance is required, an antireflection film may be laminated on the back surface of the support, if necessary, to provide antireflection properties.

[0031]

The function of the recording charge transport layer, which is a feature of the present invention, will be described. FIG. 2 is a diagram comparing the charging characteristics of the recording charge retaining layer and the recording charge transporting layer. In the figure, the mark ◯ indicates the recording charge retaining layer and the mark ● indicates the charging characteristic of the recording charge transporting layer. As an experiment, a medium in which only the recording charge retention layer was laminated on the electrode and a medium in which only the recording charge transport layer was laminated on the electrode were prepared, and the scorotron charger shown in FIG. 3 was used. : -7K
V, grid voltage-800 V, corona wire-grid distance 10 mm, grid-electrostatic recording medium distance 2
The surface potential (V) formed on the surface of the electrostatic recording medium by changing the charging time to 0 mm was measured. From FIG. 2, it can be seen that charges are hardly accumulated in the recording charge transport layer.

As described above, the electrostatic charge recording medium of the present invention is
By forming a recording charge holding layer and a recording charge transport layer on the electrode in this order, the information charges recorded on the surface of the recording charge transport layer are transported by the electric field generated by the electrode. It is transported in the layer width direction and is stably accumulated in the recording charge retention layer.

After recording, since the recording charge transport layer is made of a fluororesin, the water absorption rate is low, the moisture resistance is excellent, and the surface of the electrostatic charge recording medium is in contact with other substances. Also, it is possible to prevent the information charges from being disturbed and stably hold them. Examples will be described below.

[0034]

EXAMPLE An indium tin oxide (ITO) electrode was laminated on a glass substrate having a thickness of 1 mm by a vapor deposition method (resistivity 10
^-4 Ω · cm). On this electrode, a fluorine-containing resin (trade name “CYTOP (crosslinked type) manufactured by Asahi Glass Co., Ltd., dielectric constant 2.1 (50 Hz to 1 MHz), water absorption rate 0.01% or less, glass transition point 108 ° C., ratio) Resistance 1 × 10 ¹⁷ Ω ・ c
m,) was dissolved in perfluoro (2-butyltetrahydrofuran), and a 5 wt% solution was spin-coated (700 rpm, 20 seconds) and dried at 250 ° C. to form a recording charge retention layer having a thickness of about 3.5 μm. Formed.

Fluorine-containing fluorine-containing resin (trade name "CYTOP (s type)") was formed on the recording charge retention layer.
Asahi Glass Co., Ltd., dielectric constant 2.1 (50Hz ~ 1MH
z), a water absorption rate of 0.01% or less, a glass transition point of 108 ° C.,
Specific resistance 1 × 10 ¹⁷ Ω · cm, was dissolved in perfluoro (2-butyltetrahydrofuran), the 7% solution was spin-coated (700 rpm, 20 seconds), leveled at room temperature for 2 hours, then at 180 ° C. And dried for 1 hour to form a recording charge transporting layer having a film thickness of about 2.5 μm to prepare an electrostatic recording medium of the present invention.

[0036]

Comparative Example 1 Similar to Example 1, an electrostatic charge recording medium for comparison was prepared by laminating only the recording charge retaining layer on the electrode.

[0037]

Comparative Example 2 A fluorine-containing resin (trade name “CYTOP (standard product)” manufactured by Asahi Glass Co., Ltd., which was not treated with fluorine gas after laminating a recording charge retention layer on an electrode as in Example 1 Rate 2.1 (50Hz-1MHz), water absorption 0.01%
Below, glass transition point 108 ° C, specific resistance 1 × 10 ¹⁷ Ω · c
m,) was dissolved in perfluoro (2-butyltetrahydrofuran), the 7% solution was spinner coated (700 rpm, 20 seconds), leveled for 2 hours at room temperature, and then dried at 180 ° C. for 1 hour to give a film thickness. About 2.5μ
Then, an electrostatic charge recording medium for comparison was prepared by laminating it on the layer m.

(Charging Characteristics of Electrostatic Recording Medium) With respect to each electrostatic recording medium produced in the above-mentioned Examples and Comparative Examples 1 and 2, the scorotron charger shown in FIG. 3 (charging condition: corona wire voltage: -7KV, Corona wire-distance between electrostatic charge recording medium 30mm, charging time 0.1
Seconds. Pulse) was used for charging and the charging potential of the surface of the electrostatic recording medium was measured. The results are shown in Fig. 4.

From the figure, the charging potential of the electrostatic recording medium □ of the present invention almost matched the charging potential of the electrostatic recording medium 1 prepared in Comparative Example 1. On the other hand, the charging potential of the electrostatic recording medium ◯ prepared in Comparative Example 2 was higher than that of the electrostatic recording media of the present invention and Comparative Example 1. This is considered to be because the electrostatic charge recording medium of Comparative Example 2 also functions as a recording charge holding layer in the uppermost layer, and the accumulated potential becomes higher than that of the electrostatic charge recording medium of Comparative Example 1 by that amount.

From these results, in the electrostatic recording media of Comparative Example 1 and Comparative Example 2, the recording charges were present on the medium surface, whereas in the electrostatic recording media of the present invention,
It is considered that most of the recording charge moved in the recording charge transport layer, was retained in the recording charge retaining layer, and entered the inside of the medium.

(Contact Resistance of Electrostatic Recording Medium) Polyethylene terephthalate having aluminum deposited on the back surface of each electrostatic recording medium of Examples and Comparative Examples 1 and 2 charged as described above. 100 films
After adhering under a pressure condition of Kgf / cm ² , peeling off,
The contact resistance of the recording potential on the medium was measured. At this time, the initial recording potential was adjusted to an electric field strength of −80 V / μm.

FIG. 5 shows the measurement results of changes in potential (potential holding ratio) after 10 contact peeling operations. The electrostatic recording medium (1) of Comparative Example 1 and the electrostatic recording medium (O) of Comparative Example 2 were -28.
The initial potential was reduced by 80 to 85% by the contact peeling test when 0 V was -218 V and -463 V was -395 V, whereas the electrostatic recording medium □ of the present invention had an initial potential of -461.
It was found that V was −444V, which kept 95% of the initial potential, and the charged electric charge entered the inside of the medium, thus improving the contact resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing each aspect of an electrostatic recording medium of the present invention.

FIG. 2 is a diagram comparing charging characteristics of a recording charge retention layer and a recording charge transport layer.

FIG. 3 is a diagram for explaining an outline of a scorotron charger.

FIG. 4 is a diagram for explaining charging characteristics of an electrostatic charge recording medium.

FIG. 5 is a diagram for explaining contact resistance of the electrostatic charge recording medium.

[Explanation of symbols]

3 is an electrostatic charge recording medium, 10 is an electrostatic charge holding layer, 11 is a recording charge holding layer, 12 is a recording charge transport layer, 13 is an electrode, and 15
Is a support.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takashi Aono 1-1-1, Ichigayaka-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (72) Inventor Tokuhide Sugiyama 1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Address Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Hide Nakamura 1150, Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. In an electrostatic charge recording medium having an electrostatic charge retaining layer on at least an electrode layer, the electrostatic charge retaining layer comprises a polymer having a fluorine-containing alicyclic structure and a fluorine-containing layer on the recording charge retaining layer. An electrostatic charge recording medium comprising a recording charge transport layer made of a polymer obtained by subjecting a polymer having an alicyclic structure to a contact treatment with fluorine gas. 2. The electrostatic charge recording medium according to claim 1, wherein the polymer having a fluorinated alicyclic structure is a polymer having an alicyclic structure in its main chain.