JP3046087B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used in an electrophotographic system in which exposure and development are performed almost simultaneously without corona charging.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic image forming apparatus, a Carlson method for charging a photosensitive member by corona discharge has been widely used. In this method, a corona charger, an exposing unit, a developing unit, a transferring unit, a cleaning unit, a discharging unit, and the like are arranged around a drum-shaped or belt-shaped photoconductor, and a charging, exposing, developing, transferring, and fixing process is performed. After that, an image is formed on the recording paper, which complicates the configuration of the device and the image forming process.A high-voltage power supply is required for corona discharge, and ozone is generated due to corona discharge, causing There were problems such as adverse effects.

In order to solve these problems, an electrophotographic system which does not require corona discharge has recently been proposed (Japanese Patent Laid-Open No. 58-4 / 1983).
4445, JP-A-58-153957, JP-A-61-46961, JP-A-62-280772, etc.).

According to the electrophotography system proposed above, a drum-shaped or belt-shaped photoconductor in which a light-transmitting conductive layer and a photoconductive layer are sequentially laminated on a light-transmitting support is placed on the light-transmitting support side. The surface of the photoreceptor is rubbed with a magnetic brush made of conductive magnetic toner on the developing device to which a bias voltage is applied by a power source for supplying a developing bias while being exposed by an exposing device. At substantially the same time to form a toner image on the photoreceptor. The toner image is transferred to recording paper using a transfer roller and fixed by a fixing unit to form a recorded image. On the other hand, the toner remaining on the photoreceptor is collected by a developing device and reused.

In such an electrophotographic system,
It has been proposed to use an amorphous silicon (hereinafter, amorphous silicon is abbreviated as a-Si) layer for the photoconductive layer (JP-A-63-240553 and JP-A-2-106761).

[0006]

However, according to experiments conducted by the present inventors, in the above-described proposed electrophotographic method, an image having a sufficient image density and high image quality can be obtained. Was difficult. Also, even when using a photoreceptor having an a-Si photoconductive layer, even if an attempt is made to obtain a good image by reducing the layer thickness, a satisfactory image density has not yet been obtained, and Even if an attempt is made to increase the image density by increasing the bias voltage, the dielectric strength of the photoreceptor is low, so that the dielectric breakdown is apt to occur, which causes a problem that the desired image density cannot be obtained. Improvement was needed.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a highly reliable and high quality image forming apparatus having a sufficient image density and good image quality in an electrophotographic system which does not require corona discharge. Is to provide.

[0008]

According to the image forming apparatus of the present invention, a light-transmitting conductive layer is formed on a light-transmitting support, and an insulating carrier injection blocking layer is formed on the light-transmitting conductive layer; The thickness is 0.
An a-Si based photoconductive layer having a thickness of 5 to 5 [mu] m; an insulating layer made of amorphous silicon carbide (hereinafter, amorphous silicon carbide is abbreviated as a-SiC) or a high resistance layer having a dark resistivity of 10 < ¹³ > [Omega]. And a developing means disposed on the surface layer side of the photoconductor, and a light source for irradiating the photoconductor with light from the transparent support side to form an image with a developer. And the thickness of the photoconductive layer is 0.1 to 2.0 μm with respect to the thickness at which 90% of the light is absorbed by the light source.
In addition, the photosensitive member and the developing means are moved in the opposite directions at the closest portions of both to provide a developer reservoir,
The developer reservoir is irradiated with a light source.

[0009]

The present invention will be described below with reference to examples. FIG.
FIG. 1 is a schematic view showing an electrophotographic method using the image forming apparatus 1 of the present invention. In the drawing, reference numeral 2 denotes a translucent conductive layer 4, an insulating carrier injection blocking layer 5a, and a photoconductive layer 5 on a translucent support 3. And a drum-shaped photoconductor on which a surface layer 6 is laminated, 7 is an LED head as exposure means, 8 is a developing device, and 9 is a transfer roller. The LED head 7 and the developing device 8 are arranged substantially symmetrically via a part of the photoconductor 2. Reference numeral 10 denotes an LED array as an erasing light source, which may be arranged outside the photoconductor 2. The developing unit 8 includes, for example, a columnar magnetic pole roller 11 having eight poles and a conductive sleeve 12 disposed around the outer circumference thereof. The conductive toner is delivered to the outer periphery of sleeve 12 to form magnetic brush 14.
A bias power supply 15 is provided between the sleeve 12 and the light-transmitting conductive layer 4, and a voltage of 0 to 300 V of + or − is applied between the two according to the potential characteristics of the photoconductor 2. Apply. Reference numeral 16 denotes a toner layer formed on the surface of the photoconductor 2, reference numeral 17 denotes recording paper, and reference numeral 18 denotes residual toner. In addition, a rotating means for the developer and a rotating means for the photoconductor 2 are provided.

Thus, according to the image forming apparatus having the above structure, the light-transmitting support 3 of the rotating photoreceptor 2 is irradiated with light for image exposure from the LED head 7 so that the inside of the a-Si photoconductive layer 5 is formed. When holes and electrons are generated, if a positive bias voltage is applied to the developing device 8 side, the electrons move to the surface side of the a-Si photoconductive layer 5 by the bias voltage, and the magnetic brush 1
The conductive toner is canceled on the positive charge at the terminal of the photosensitive member 4 and adheres to the surface of the photoconductor 2. Then, the conductive toner is transferred onto the recording paper 17 by the transfer roller 9 and then fixed.

Although the LED head is used here as the exposure means, a means using a laser or a liquid crystal shutter may be used.
As the erasing light source 10, a light source such as a halogen lamp, a fluorescent lamp, and an EL array can be used in addition to the LED array.

FIG. 2 is an explanatory view showing a part of the photoreceptor 2 and a developer reservoir 19 formed by the developing means 8.

The developing device 8 for holding the developer includes a conductive sleeve 12 and a magnetic pole roller 11 disposed therein.
The developer may be conveyed by fixing the magnetic pole roller 11 and rotating the sleeve 12, or
May be fixed and the internal magnetic pole roller 11 may be rotated.

Here, when the developer is rotated in the opposite direction to the photosensitive member 2, the friction between the two causes the developer reservoir 19 to be located downstream (the side where the developer is separated) from the closest part between the developing device 8 and the photosensitive member 2. Occurs. The developer reservoir 19 is a portion separated by a broken line in the figure. That is, the portion of the developer protruding from the original height is the developer reservoir 19, and the transport speed of the developer, the height of the developer, and the gap between the sleeve 12 and the surface of the photoreceptor 2 are:
It is set appropriately according to the rotation speed of the photoconductor 2 and the required size of the developer reservoir 19.

When the photosensitive member and the developer are rotated in opposite directions, a developer pool is generated downstream of the closest portion between the developing means and the photosensitive member due to friction between the photosensitive member and the developer. And more stable and higher reproducibility than when the peripheral speed of the developer is made higher than the peripheral speed of the photoconductor. Therefore, in order to stably obtain the developer reservoir with good reproducibility, it is preferable to rotate the photoconductor and the developer in opposite directions.

Reference numeral 20 denotes a control electrode. The control electrode 20 is provided on the sleeve 12 at a position closest to the photosensitive member 2, and is insulated from the sleeve 12 by an insulator 21. Control electrode 2
0 is such that a uniform electric field is applied to the photoconductor 2 and the developer.
The belt 12 is shaped like a band along the length direction of the sleeve 12.

A voltage marking means 22 for setting the potential of the control electrode 20 independently of the potential of the developing means is provided.
It is preferable to provide a voltage applying means 22 to the control electrode 20 so that the image density is improved when a voltage is applied to the control electrode 20.

As the developer, for example, a conductive magnetic toner is used, which forms the magnetic brush 14 and the developer reservoir 19, and may be a one-component developer if it has the necessary conductivity. A two-component developer having a required conductivity by mixing a carrier and an insulating toner at a predetermined mixing ratio may be used.

The position where image exposure is performed is not the closest position A between the surface of the photosensitive member 2 and the developing sleeve 12, but the position B of the developer reservoir 19 formed on the downstream side by the reverse rotation of the photosensitive member 2. Preferably, it is the latter half of the developer reservoir 19 on the downstream side. By performing the exposure at the position of the developer reservoir 19, the photoconductor 2 is sufficiently charged before the exposure, and the influence of the potential history of the photoconductor 2 before charging is suppressed. The toner remaining on the surface and the toner in the image background are sufficiently collected. Furthermore, since the photosensitive member 2 is sufficiently charged and exposed to light to eliminate the charge, the electric attraction between the developer and the photosensitive member 2 is strong, and a good toner image 16 is formed. After the toner image 16 is formed, the photoconductor 2 is quickly separated from the developer reservoir 19, so that the toner image 16 on the surface of the photoconductor 2 is disturbed by mechanical force such as collision or friction of the developer. Thus, the toner image 16 having a good resolution can be obtained.

It is to be noted that, when the exposure is performed in the developer pool, and preferably when the exposure is performed on the downstream side of the upstream side of the developer pool,

(1) The contact distance between the photosensitive member and the developer before exposure is long, and uniform and sufficient charging can be obtained. As a result, a uniform and sufficient density toner image can be obtained.

(2) Since the contact distance between the developer and the photoreceptor before the exposure is long, the residual toner on the photoreceptor surface and the toner adhering to the image background can be sufficiently recovered to reduce the background fog.

(3) The photosensitive member quickly separates from the developer after the exposure, so that the exposed portion of the photosensitive member is recharged by the developer, so that the adhesion between the photosensitive member and the toner is weakened and the toner adheres to the surface of the photosensitive member. The problem that the toner is collected by the developing means and the toner concentration is reduced can be reduced.

(4) Since the photoconductor quickly separates from the developer after exposure, disturbance of the toner image due to mechanical force such as friction between the toner image formed on the photoconductor surface and the developer can be reduced.

(5) Since the distance between the developing means and the photoreceptor at the exposure position is large, there is an advantage that the toner adhered to the photoreceptor surface due to the magnetic force of the developing means and the like and the disturbance of the toner image can be reduced. In order to form a uniform image, it is preferable that the image exposure is performed at the developing pool, preferably at the downstream side of the developer pool.

At the position of the developer reservoir 19, the position of the surface A of the photosensitive member 2 and the developing sleeve 12 is closer than the position A where it is closest.
The distance between the surface of the photoconductor 2 and the magnetic pole roller 11 increases.
Therefore, the magnetic force that attracts the developer toward the magnetic pole roller 11 is weak, and a part of the toner image 16 formed on the surface of the photoreceptor 2 is collected by the magnetic force toward the developing unit, and the image density is reduced. In addition, it is possible to prevent the resolution from being lowered by being disturbed by the magnetic force.

Further, a belt-shaped control electrode 20 is provided, and its potential is adjusted to a predetermined potential by a power supply 22. For example, the control electrode 20 is grounded and set to the same potential as the translucent conductive layer 4. Alternatively, the potential is set lower or higher than the potential of the sleeve 12.

As described above, when the control electrode 20 capable of applying a potential independently of the sleeve 12 is provided, the surface potential of the photosensitive member 2 is neutralized through the developer, or the potential of the surface of the photosensitive member 2 is made uniform. The influence of the history of the photoconductor 2 due to the presence or absence of charging or exposure in the previous process can be canceled out. As a result, when the photoconductor 2 is repeatedly used, for example, when the photoconductor 2 is rotated several times to obtain one image, In addition, a stable developed state and a recorded image can be obtained. Here, when the potential of the control electrode 20 is adjusted, it is possible to adjust and obtain optimum image forming conditions for image density, background fog, and the like. The control electrode 20
By raising the potential of the sleeve 12 and lowering the potential of the sleeve 12, the toner adheres to the non-exposed portion and the toner does not adhere to the exposed portion, so-called reversal development has become possible.

The toner image 16 formed on the surface of the photosensitive member 2
Is transferred to a recording paper 17 and fixed to form a recorded image. The residual toner 18 remaining on the surface of the photoreceptor 2 without being transferred is collected by a developing unit in the next image forming process and reused.

Further, by irradiating the light-removing light from the eraser light source 10 to the photoreceptor 2 after the transfer, the influence of the history of the photoreceptor 2 due to the charging or the presence or absence of the exposure in the previous process is more effectively canceled. It is possible to suppress an image problem such as an afterimage phenomenon at the time of repeated use. Further, the carrier trapped at the interface between the photoconductive layer 5 and the surface layer 6 of the photoconductor 2 is erased to eliminate the electric attraction between the photoconductor 2 and the residual toner on the surface thereof, and the residual toner is developed. 8 can be easily collected.

In these figures, the photosensitive member 2 has a light-transmitting conductive layer 4 formed on the outer peripheral surface of a drum-shaped light-transmitting support 3, and furthermore, has an insulating carrier injection prevention on the light-transmitting conductive layer 4. This is a configuration in which a layer 5a, a photoconductive layer 5, and a surface layer 6 are stacked.

The material constituting the translucent support 3 includes:
Examples include pyrex glass, soda glass, borosilicate glass, and the like; inorganic materials such as quartz and sapphire; and organic resin materials such as fluorine resin, polyester, polycarbonate, polyethylene terephthalate, vinylon, epoxy, and mylar.

The material forming the transparent conductive layer 4 includes:
There are indium-tin-oxide (ITO), tin oxide, lead oxide, indium oxide, copper iodide, and the like, and a metal layer made of Al, Ni, Au, or the like thinned to be translucent may be used. . The layer forming method includes vacuum deposition, active reactive deposition, RF sputtering, DC sputtering, RF magnetron sputtering, DC magnetron sputtering, thermal CVD, and plasma CV.
D method, spray method, coating method, dipping method and the like.

The insulating carrier injection blocking layer 5a is
When the surface adheres to the developer while a bias voltage is applied, injection of carriers from the translucent conductive layer 4 into the a-Si based photoconductive layer 5 is prevented, so that the exposed portion and the non-exposed portion can be separated. In addition to improving the image density by increasing the electrostatic contrast,
Reduces background fogging during development.

This layer 5a has insulating a-SiC, a-SiC
O, a-SiN, a-SiON, a-Si based insulating layer such as a-SiCON, polyethylene terephthalate and parylene, polytetrafluoroethylene, polyimide, polyfluoroethylene propylene, urethane resin, epoxy resin, polyester resin, It is preferable to use a polycarbonate resin, a cellulose acetate resin, another organic insulating layer, or the like.

The layer 5a has a high light-transmitting property (a large optical band gap or a high light transmittance) as well as an insulating property so as not to absorb the light for image exposure from the light-transmitting support 3 side. ) In addition, it is necessary to have good adhesion to the light-transmitting conductive layer 4 and the a-Si-based photoconductive layer 5, and not to cause a large deterioration in heating or the like when forming the a-Si-based photoconductive layer 5. It is.
The thickness of the carrier injection blocking layer 5a made of an insulating layer is set to 0.1 mm.
The range is preferably from 01 to 5 μm, and more preferably from 0.1 to 3 μm.

As the photoconductive layer 5, it is particularly preferable to use an a-Si based photoconductive layer. The a-Si based layer is formed by, for example, a glow discharge decomposition method, a sputtering method, an ECR method, a vapor deposition method or the like. In the formation thereof, hydrogen (H) or a halogen element is contained in an amount of 1 to 40 atomic% for dangling bond termination. In addition, in order to obtain desired electrical characteristics such as dark conductivity and photoconductivity of the layer and optical band gap, an element belonging to Group IIIa of the periodic table (hereinafter referred to as II of the periodic table).
Group Ia elements are abbreviated as Group IIIa elements), Group Va elements (hereinafter abbreviated as Group Va elements), and elements such as carbon (C), nitrogen (N), and oxygen (O). Good. In particular, when amorphous silicon carbide (hereinafter, amorphous silicon carbide is abbreviated as a-SiC) is used for the photoconductive layer 5, the x value of Si _1-X C _x is set to 0 <x
≦ 0.5, preferably in the range of 0.05 ≦ x ≦ 0.45. This range is desirable in that the resistance becomes higher than that of the a-Si layer and good carrier traveling can be ensured. As the group IIIa element and the group Va element, the B element and the P element are preferable because they have excellent covalent bonding properties and can change semiconductor characteristics sensitively, and furthermore, excellent light sensitivity can be obtained.

Further, when the a-Si based photoconductive layer 5 is formed by laminating a layer region having an enhanced photocarrier generation function and a layer region having a carrier transport function, the photosensitivity and the photosensitivity can be improved. Both the withstand voltage and the like can be increased.

At this time, in order to enhance the generation of photocarriers, the photoexcitation layer region should be formed under the following conditions:
It is preferable to form the film at a low film forming rate, (3) increase the dilution ratio with H ₂ or He, and (4) to include a larger amount of the element to be doped than the transport layer.

The carrier transport layer region mainly serves to increase the breakdown voltage of the photoreceptor 2 and to allow the carriers injected from the excitation layer region to smoothly travel to the surface of the photoreceptor 2. Carriers are generated by the light transmitted through the layer region, which contributes to the photosensitivity of the photoconductor 2.

The thickness of the a-Si-based photoconductive layer 5 is a thickness obtained by further adding 0.1 to 2.0 μm to the depth of light absorption determined from the absorption coefficient of this layer for light having an exposure wavelength.

FIG. 3 shows a typical a-Si: H layer (Egop
(t: 1.76 eV) shows the change in the depth of light absorption obtained from the absorption coefficient with respect to the wavelength of light. AS from Figure 3
The depth at which 90% of the incident light is absorbed in the i: H layer is
About 0.4 μm for wavelength 550 nm, general EL
About 0.6 μm for the emission wavelength of 580 nm,
About 0.8 μm for 600 nm, about 2.2 μm, 7 for a wavelength of 660 nm which is one of general LEDs.
It can be seen that it is about 3.8 μm for 00 nm.

Such a change in the light absorption depth is caused by a-
Depending on the light absorption characteristics of the Si-based photoconductive layer 5, the thickness of the a-Si based photoconductive layer 5 is determined by the absorption coefficient with respect to the wavelength of light. By setting the absorption depth to a thickness obtained by adding 0.1 to 2.0 μm, the exposure wavelength can be almost completely absorbed, and a photocarrier can be generated effectively. No more.

By setting the thickness of this layer to the necessary minimum set above, the electric field applied to the photoconductive layer 5 by the bias voltage at the time of image formation becomes sufficiently high even at a low bias voltage. Image formation can be performed.

When the a-Si-based photoconductive layer 5 is formed by laminating a photoexcitation layer region and a transport layer region,
It is preferable that the thickness of the photoexcitation layer region is set substantially equal to the absorption depth.

The surface layer 6 is an insulating layer and is formed of an organic material or an inorganic material. In particular, a-SiC and a-Si such as amorphous silicon nitride (a-SiN), amorphous silicon oxide (a-SiO), amorphous silicon oxycarbide (a-SiCO), and amorphous silicon oxynitride (a-SiNO) It is preferable to use a system insulating layer, which is formed by the same thin film forming means as the photoconductive layer 5. When a-SiC is used for the surface layer 6 and the photoconductive layer 5, carbon in the surface layer 6 is contained more than the amount of carbon contained in the photoconductive layer 5. The amount of carbon in the surface layer 6 is represented by the following _equation : x ≦ Si _1−X C _x 0.3 ≦ x <1.
0, preferably in the range of 0.5 ≦ x ≦ 0.95. A gradient may be formed in the carbon amount in this layer, or N, O, and Ge may be contained together with carbon to further improve the moisture resistance.

The thickness of the surface layer 6 is 0.05 to 5 μm, preferably
0.1 to 3 μm, and if less than 0.05 μm,
The layer 6 cannot sufficiently improve the withstand voltage or effectively trap optical carriers to contribute to the formation of a toner image. In addition, when used repeatedly, the life is inferior due to abrasion. When the thickness exceeds 5 μm, an electric field (lines of electric force) spreads in the film surface direction in this layer 6 to form a fine charge pattern, thereby lowering the resolution and obtaining a sufficient resolution. I can't. Further, since the amount of charge remaining on the surface increases and the residual potential increases, problems such as a reduction in image density, fogging of a back, and a change in image density during repeated use occur.

When the surface layer 6 is an a-SiC high resistance surface layer, it is formed by the same thin film forming means as the a-SiC photoconductive layer 5. The dark resistivity of the surface layer 6 is 10 ¹³
C content and impurity addition amount so as to be Ω · cm or more,
The film forming conditions are appropriately set.

As described above, the dark resistivity of the surface layer 6 is 10 ¹³ Ω.
If it is not less than cm, the injection of charges due to the bias through the developer is prevented, the potential contrast between the exposed and unexposed portions is increased, and more toner is attracted to the surface of the photoconductor 2 to reduce the density of the toner image. And the image density can be sufficiently increased, and the fogging of the back can be suppressed.

Further, the dielectric strength of the photosensitive member 2 can be increased.

Further, when a normal insulating layer is used, photocarriers continue to be trapped in the insulating layer even after image formation, and there is a problem that the residual potential cannot be erased by normal erase exposure. In the case of the -SiC high resistance layer, the positive electric charge from the surface is effectively blocked, but the negative electric charge from the photoconductive layer 5 is relatively easy to pass. There is also an advantage that the image can be effectively erased by the erase exposure and the image can be continuously formed.

In addition to having good adhesion to the a-Si-based photoconductive layer 5, characteristics such as abrasion resistance and environmental resistance are also improved.
Stable image formation can be performed over a long period of time.

The _X value of the a-Si _1-X C _X is 0.3 ≦ _X <
1.0, preferably 0.5 ≦ _X ≦ 0.95, and the C content may have a gradient in the layer. When N, O, and Ge are contained at the same time as C, the moisture resistance can be further enhanced.

The thickness of the a-SiC high resistance layer is 0.05 to
5 μm, preferably within the range of 0.1 to 3 μm.

The total thickness of the photoreceptor layer thus obtained depends on the above setting, but the LED or EL is used as an exposure light source.
When used, about 1 to 15 μm, preferably 2 to 10 μm
The range of μm is good, and within this range, the exposure is sufficiently absorbed and good photosensitivity is exhibited, the withstand voltage of the photoreceptor can be secured, and a good image can be obtained even with a low bias voltage.

Next, each embodiment will be described in detail. (Example 1) (Example 5) (Example 7) (Example 9) (Example 1)
1) (Example 12), and comparative examples are described in (Example 2) (Example 3) (Example 4) (Example 6) (Example 8) (Example 10) (Example 13).

(Example 1) An ITO layer was formed on the outer peripheral surface of a transparent cylindrical glass substrate as a light-transmitting conductive layer to a thickness of 1000 ° by an active reactive vapor deposition method, and then a capacitively coupled glow discharge decomposition apparatus was formed thereon. The a-Si injection blocking layer, the a-Si photoconductive layer, and the a-SiC high resistance surface layer were sequentially laminated under the film forming conditions shown in Table 1 to prepare a photoconductor A.

[0058]

[Table 1]

The photosensitive member A is mounted on an image forming apparatus as shown in FIG.
And a voltage of Vs = + 30 V is applied between the
m, image exposure under the condition of exposure amount 0.5 μJ / cm ² ,
A toner image was formed on the photoreceptor, the toner image was transferred to a recording paper, and heat-fixed to obtain an image.

When this image was evaluated, it was an image having an optical density (hereinafter, referred to as OD) of 1.3 and having good resolution without fogging of the background.

(Example 2) In producing the photoconductor A, a-
The thickness of the Si photoconductive layer is set to 1.5, which is smaller than the thickness of about 2.2 μm for absorbing 90% of the light of the wavelength 660 nm of the LED of the light source.
μm, and photoreceptor B was prepared.

This photoconductor B was mounted on an electro-optical recording apparatus of the optical backside recording type having the structure shown in FIG. 2 in the same manner as in (Example 1), and the bias voltage was set to +20 V so that the electric field of the photoconductor layer was the same. When image evaluation was performed under the same conditions, photocarriers were not sufficiently generated, and the image density was 0.8, which was insufficient.

(Example 3) In producing the photosensitive member A, a-
Photoconductor C was fabricated by setting the thickness of the Si photoconductive layer to 5.2 μm, which is 3.0 μm larger than the thickness of about 2.2 μm that absorbs 90% of the light of 660 nm wavelength of the LED of the light source.

This photoconductor C was mounted on an electro-optical recording apparatus of the optical backside recording type having the configuration shown in FIG. 2 in the same manner as in (Example 1), and the bias voltage was set to +60 V so that the electric field of the photoconductor layer was the same. The image was evaluated under the same conditions. As a result, an image having an image density of 1.2 and an image having generally good fog and resolution was obtained.

However, when the image evaluation was performed under the same conditions with the bias voltage set to +30 V, sufficient potential contrast was not obtained, and the image had an image density as low as 0.9.

(Example 4) In producing the photosensitive member A, a-
Photoconductor D was prepared in the same manner except that no SiC injection blocking layer was formed.

This photosensitive member D was mounted on an electrophotographic apparatus of the optical backside recording type having the structure shown in FIG. 2 in the same manner as in (Example 1), and (Example 1)
The image was evaluated under the same conditions as in Example 1. As a result, fogging of the back of the image was observed, and the result was inferior to that of Photoconductor A.

(Example 5) In producing the photosensitive member A, a-
Instead of the SiC injection blocking layer, a polyimide layer having a thickness of 0.
An insulating layer of 2 μm was formed by a coating and drying method. Further, an a-Si photoconductive layer and an a-SiC high-resistance surface layer similar to those in (Example 1) were sequentially laminated thereon by using a capacitively-coupled glow discharge decomposition apparatus, thereby producing a photoconductor E. .

This photoreceptor E was mounted on an electrophotographic apparatus of the optical backside recording type having the configuration shown in FIG. 2 and image evaluation was performed under the same conditions as in (Example 1). D. Has an image density of 1.3, has no fogging of the background, and has a good resolution.

(Example 6) In producing the photosensitive member A, a-
Photoconductor F having no a-SiC high resistance surface layer under the same conditions as Photoconductor A, except that the SiC high resistance surface layer is not laminated.
Was prepared.

This photoconductor F was mounted on an electrophotographic apparatus of the optical backside recording type having the structure shown in FIG. 2 and image evaluation was performed under the same conditions as in (Example 1). The image was low and the fogging of the back was conspicuous, and the result was inferior to that of the photoconductor A.

(Example 7) In producing the photoreceptor of (Example 1), the film forming conditions shown in Table 2 were used instead of the layers shown in Table 1.
An a-SiC injection blocking layer, an a-Si photoconductive layer, and an insulating a-SiC surface layer were sequentially formed, and the other components were manufactured under the same conditions as in Example 1 to obtain a photoconductor G.

[0073]

[Table 2]

This photoreceptor is mounted on an electrophotographic apparatus of the optical backside recording type having the configuration shown in FIG. 2, and an LED head is arranged at a position inside the photoreceptor opposite to the developing device. While applying a voltage of +30 V between the transparent electrode layer and the substrate, image exposure is performed under the conditions of a wavelength of 660 nm and an exposure amount of 0.5 μJ / cm ² to form a toner image on a photoconductor, and the toner image is formed. The image was transferred to a recording paper and heat-fixed to obtain an image. When this image was evaluated, O.D. D. Has an image density of 1.3, has no fogging of the background, and has a good resolution.

(Example 8) In producing the photoconductor G, a-
The thickness of the Si photoconductive layer is set to 1.5, which is smaller than the thickness of about 2.2 μm for absorbing 90% of the light of the wavelength 660 nm of the LED of the light source.
μm, and photoreceptor H was prepared.

This photoconductor H was mounted on an electro-optical recording apparatus of the optical backside recording type having the configuration shown in FIG. 2 in the same manner as in (Example 7), and the bias voltage was set to +20 V so that the electric field of the photoconductor layer was the same. When image evaluation was performed under the same conditions, photocarriers were not sufficiently generated, and the image density was 0.8, which was insufficient.

(Example 9) In producing the photoconductor G, a-
Photoconductor I was manufactured by setting the thickness of the Si photoconductive layer to 5.2 μm, which is 3.0 μm larger than the thickness of about 2.2 μm that absorbs 90% of the light of 660 nm wavelength of the LED of the light source.

This photoconductor I was mounted on an electro-photographic apparatus of the optical backside recording system having the structure shown in FIG. 2 in the same manner as in (Example 7), and the bias voltage was set to +60 V so that the electric field of the photoconductor layer was the same. The image was evaluated under the same conditions. As a result, an image having an image density of 1.2 and an image having generally good fog and resolution was obtained.

However, when image evaluation was performed under the same conditions with the bias voltage set to +30 V, sufficient potential contrast was not obtained, and the image had an image density as low as 0.9.

(Example 10) In manufacturing the photoconductor G,
a-SiC injection blocking layer is not formed, and
Was prepared.

This photoconductor J was mounted on an electrophotographic apparatus of the optical backside recording type having the configuration shown in FIG. 2 in the same manner as in (Example 7), and (Example 7)
When the image was evaluated under the same conditions as in the above, fogging of the back of the image was observed, and the result was inferior to that of the photoconductor G.

(Example 11) In manufacturing the photoconductor G,
Instead of the a-SiC injection blocking layer, a 0.2 μm thick insulating layer made of polyimide was formed by a coating and drying method. Furthermore, using a capacitively coupled glow discharge decomposition device,
An a-Si photoconductive layer similar to (Example 7) and an insulating a-SiC surface layer were sequentially laminated to produce a photoconductor K.

This photoreceptor K was mounted on an electrophotographic apparatus of the optical rear recording type having the structure shown in FIG. 2 and the image was evaluated under the same conditions as in (Example 7). D. Has an image density of 1.3, has no fogging of the background, and has a good resolution.

(Example 12) In producing the photoconductor G,
Instead of a-SiC surface layer, 0.1μ thick parylene
A photoconductor L having no insulating surface layer was manufactured under the same conditions as the photoconductor G except that an insulating layer of m was formed by a vacuum evaporation method.

This photoreceptor L was mounted on an electrophotographic apparatus of the optical backside recording type having the structure shown in FIG. 2 and image evaluation was performed under the same conditions as in (Example 7). D. Has an image density of 1.3, has no fogging of the background, and has a good resolution.

(Example 13) In manufacturing the photoconductor G,
Photoreceptor M having no insulating surface layer was prepared under the same conditions as photoreceptor G except that no a-SiC surface layer was prepared.

This photoconductor M was mounted on the electrophotographic apparatus of the optical backside recording type having the structure shown in FIG. 2 and image evaluation was performed under the same conditions as in (Example 7). The image was low and the fogging of the back was conspicuous, and the result was inferior to that of the photoconductor G.

[0088]

According to the image forming apparatus of the present invention, the carrier from the light-transmitting conductive layer to the a-Si-based photoconductive layer is formed during image formation by laminating the carrier injection blocking layer comprising an insulating layer. , The electrostatic contrast between the exposed and non-exposed areas was increased to improve the image density and to reduce the background fog during development.

According to the image forming apparatus of the present invention, a-
The thickness of the Si-based photoconductive layer is set to a depth of 0.1 to 2.0 μm to absorb 90% of light obtained from an absorption coefficient with respect to the wavelength of light.
By adding the thickness, the exposure wavelength was almost completely absorbed, and photocarriers could be generated effectively.

Further, by setting the thickness of the a-Si based photoconductive layer to the necessary minimum set as described above, the voltage applied to the photoconductive layer due to the bias voltage at the time of image formation can be sufficiently increased even at a low bias voltage. Therefore, good image formation can be performed.

Further, according to the image forming apparatus of the present invention, by laminating an a-SiC high-resistance layer on an a-Si-based photoconductive layer, injection of carriers from a developer can be performed in image formation. By blocking the image, the image density could be increased by increasing the contrast of the image, and good toner image formation could be performed by suppressing the back fog.

Further, the characteristics such as the dielectric strength of the photoreceptor, the abrasion resistance, the environmental resistance and the like are improved, and a stable image can be formed over a long period.

Further, by laminating an insulating layer on the a-Si-based photoconductive layer, in image formation, injection of carriers from a developer is prevented to enhance the contrast of the image and suppress fogging of the back. In addition, by forming a charge pair between the photoconductive layer and the developer via the insulating layer in the image exposure section, it is possible to form a good toner image,
The image density could be increased.

In addition, the photoreceptor has improved characteristics such as withstand voltage, abrasion resistance, and environmental resistance, so that a stable image can be formed over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an electrophotographic method according to the present invention.

FIG. 2 is a configuration diagram of a main part of the electrophotographic method of the present invention.

FIG. 3 is a diagram illustrating a light absorption depth with respect to a wavelength.

[Explanation of symbols]

 2 Photoconductor 7 LED Head 8 Developing Device 9 Transfer Roller 10 Erase Light Source 4 Translucent Conductive Layer 5 Photoconductive Layer 5a Carrier Injection Blocking Layer 6 Surface Layer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ito 6166 Kyocera Co., Ltd. Shiga Yokaichi Plant at 1166 Haseno, Jabizo-cho, Yokaichi City, Shiga Prefecture (56) References JP-A 1-227166 (JP, A) 2-106761 (JP, A) JP-A-57-17952 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/05 G03G 5/08 105-360

Claims (1)

(57) [Claims] 1. A light-transmitting conductive layer is formed on a light-transmitting support,
An insulating carrier injection blocking layer, an amorphous silicon-based photoconductive layer having a thickness of 0.5 to 5 μm, an insulating layer or amorphous silicon carbide on the light transmitting conductive layer.
A photoreceptor dark resistivity by sequentially laminating a surface layer according to 10 ¹³ Ω · cm or more high-resistance layer composed of a developing means disposed on the surface layer side of the photoreceptor, developer to the photosensitive member And a light source for irradiating from the translucent support side to form an image by the light source.
90% of the light that is absorbed by
1 to 2.0 .mu.m , and the photosensitive member and the developing means were moved in opposite directions at the closest portions of both to provide a developer reservoir, and the developer reservoir was irradiated with a light source. An image forming apparatus comprising: