JPH0627767A - Image recording device - Google Patents

Abstract

PURPOSE:To provide an image device capable of preventing lowering of picture image density so as to acquire a toner image on a sensitized body by way of simultaneously carrying out development when a picture image is exposed from the back face of the sensitized body. CONSTITUTION:A sensitized body 200 to be used is constituted by laminating an electrically conductive layer 202 to transmit light and a plural sensitized layers 203 divided by a plural blocking layers 204 at least on a transparent base body 201. The blocking layers 204 are arranged on the side of the transparent base body 201 of each of the sensitized layers 203. These blocking layers 204 are formed of an amorphous silicon compound, and its composition ratio continuously changes so that a silicon ratio on the side of the transparent base body 201 becomes larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus which obtains a toner image on a photoconductor by exposing the photoconductor from the back side of the photoconductor and developing the image at the same time.

Currently, copying machines or high-speed, high-quality printers generally use an electrophotographic system. This system is a so-called Carlson process in which a photoreceptor is used as a recording medium and recording is performed in steps of uniform charging, image exposure, development, transfer, fixing, charge removal, and cleaning.

In the Carlson process, a corona discharger is used for uniform charging, transfer and charge removal. Since the corona discharger is configured to apply a high voltage of several kV to the corona wire, it requires a high-voltage power source and is easily affected by humidity, dust, etc., and therefore has a drawback of low reliability. Further, ozone generated in a corona discharger has an odor, and in recent years, the harmfulness of the ions to the human body has become a problem.
Further, since the above-mentioned seven steps are required, there is a drawback that the apparatus becomes complicated and becomes large in size.

Recently, as a means for solving the above-mentioned drawbacks, an image forming method has been proposed in which a corona discharger is unnecessary and the apparatus can be downsized. Specifically, it is a system in which a toner developing machine and an image exposure unit are arranged to face each other with a photoconductor interposed therebetween, and image exposure and development are performed simultaneously. The present invention relates to that one method.

[0005]

2. Description of the Related Art FIGS. 9 to 11 show the outline of the structure of various conventional image recording apparatuses of this type. First, the apparatus of FIG. 9 will be described by using an organic photoconductor (OPC) as a photoconductor as an example. In the figure, 1 is a photoconductor, and the photoconductor 1 is
It comprises a transparent substrate 1a, a transparent conductive layer 1b, and a photosensitive layer (charge generation layer and charge transport layer) 1c, and the transparent conductive layer 1b is grounded. The magnetic brush developing machine 2 provided on the photosensitive layer 1c side of the photoconductor 1 comprises a magnet roller 2a and a sleeve 2b, and the magnet roller 2a is adapted to rotate.

Further, on the surface of the sleeve 2b, a strip-shaped recording electrode 4 is insulated from the sleeve 2b by an insulating sleeve 3.
Is provided. A voltage having a polarity opposite to the carrier polarity (positive polarity in the figure) of the photosensitive layer 1c is applied to the recording electrode 4 as a power source 6
A voltage having a polarity opposite to that of the recording electrode 4 is applied to the sleeve 2b by the power supply 7. This developing machine 2
And a developer 5 in which a conductive carrier and an insulating toner are mixed.
And then convey in the direction of the arrow in the figure. This method is
It is also possible to use a conductive one-component developer.

An image exposing means 8 is arranged on the transparent substrate 1a side of the photoconductor 1. The image exposure unit 8 is arranged so that the optical axis of exposure intersects the recording electrode 4. As the image exposure means 8, an LED array optical system, a laser optical system, E
An L optical system, a liquid crystal shutter optical system, etc. can be used. The image forming principle of this apparatus is as follows.

The photosensitive layer 1c in the section A of the apparatus having the above construction
When the image is exposed to light, photocarriers are generated in the photosensitive layer 1c. Of the photocarriers, the applied voltage (-1
Carriers having a polarity opposite to that of (00 to −600 V) move to the surface of the photosensitive layer 1c and become latent image charges 9. In this way, in the exposed portion (A portion), the electrostatic capacity of the photosensitive layer 1c apparently increases, so that the amount of adhered toner increases, and a toner image with a certain degree of contrast is formed between the exposed portion and the non-exposed portion. This step will be referred to as first development.

Next, at the portion B, a reverse voltage (0 to +100 V) is applied to the sleeve 2b, and the developer pool 11
By creating the, the excessive toner in the non-exposed portion is collected in the developing device 2 by electrostatic force. At this time, the toner in the exposed portion is also slightly recovered, but most of the toner remains on the photoconductor 1 due to the electrostatic restraining force of the latent image charge 9 and the toner charge, and the toner image 10 is formed. This step is called second development.

Next, in the apparatus shown in FIG. 10, an organic photoreceptor will be described as an example. The photosensitive member 1 is the same as that shown in FIG. 9, and the first magnetic brush developing machine 12 is provided on the photosensitive layer 1c side of the photosensitive member 1.
A second magnetic brush developing machine 13 is provided, and an image exposing means 8 similar to that shown in FIG. 9 facing the first developing machine 12 is provided on the transparent substrate 1a side. The first developing machine 12
It is composed of a magnet roller 12a and a sleeve 12b, and both the magnet roller 12a and the sleeve 12b are rotatable.

The first developing machine 12 has a first polarity opposite to the polarity of charges moving in the photosensitive layer 1c (positive polarity in the figure).
The recording voltage of 1 is applied by the power source 14,
The developing device 12 is filled with the one-component or two-component developer 15, and the developer 15 is conveyed by the rotation of the magnet roller 12a and the sleeve 12b. It should be noted that although the case where a magnetic brush developing machine using a magnetic developer is used has been described in the present description, an apparatus using a non-magnetic developer is also conceivable.

The second developing machine 13 is provided downstream of the first developing machine 12 in the moving direction of the photoconductor 1. Like the first developing machine 12, the second developing machine 13 includes a magnet roller 13a and a sleeve 13b, and both the magnet roller 13a and the sleeve 13b are rotatably configured. Further, the second developing device 13 receives a second recording voltage having a polarity opposite to that of the recording voltage of the first developing device 12 from the power source 16
Is being applied by. The second developing machine 13 is filled with one-component or two-component developer 17, and the developer 17 is conveyed by rotation of the magnet roller 13a and the sleeve 13b. The image forming principle of this apparatus is as follows.

When the photosensitive member 1 is imagewise exposed in the first developing machine 12 of the apparatus having the above-mentioned structure, electron-hole pairs are generated in the photosensitive layer 1c, and holes (positive charge) having a polarity opposite to that of the inner sleeve 12a are generated. ) Moves to the vicinity of the surface of the photosensitive layer 1c and becomes a latent image charge 18. For this reason, the electrostatic capacity of the photosensitive layer 1c apparently increases in the exposed portion, so that the amount of adhered toner increases and a toner image with a certain degree of contrast can be formed between the exposed portion and the non-exposed portion. I will decide.

Next, the photosensitive member 1 is moved and a reverse voltage is applied to the sleeve 13b by the second developing machine 13 from the power source 16, so that the non-exposed portion attached to the first developing machine 12 is excessive. The toner is collected by electrostatic force. At this time, the toner in the exposed portion is also slightly recovered, but most of the toner remains on the photoconductor 1 due to the electrostatic restraining force of the latent image charge 18 and the toner charge, and a toner image 19 is formed.
This step is called second development.

Further, the apparatus shown in FIG. 11 will be described.
The photoconductor 20 has a drum shape, and includes a transparent substrate 20a, a transparent conductive layer 20b, and a photosensitive layer (charge generation layer and charge transport layer).
The transparent conductive layer 20b is connected to the ground. The developing device 21 provided on the photosensitive layer 20 c side of the photoconductor 20 includes a developing roller 22 formed of an elastic roller such as a conductive rubber roller pressed in the direction of the photoconductor 20, and an insulating toner 23 on the developing roller 22. It has a doctor blade 24 for forming a thin layer and a recovery roller 25 composed of an elastic roller such as a conductive rubber roller pressed in the direction of the photoconductor 20, and an insulating one-component developer in the developing machine 21. Is filled.

The insulating toner 23 is conveyed by the rotation of the conductive elastic developing roller 22, and is charged to 10 to 20 μC / g by friction with the doctor blade 24. In this example, since the photoconductor 20 is of a positive charging type, the conductive elastic developing roller 22 has a positive developing bias voltage _Vb (+10 to + 1000V, preferably +).
100 to +600 V) is applied, and a negative recovery bias voltage (−0 to −5) is applied to the conductive elastic recovery roller 25.
0 V) is applied.

An image exposing means 26 is arranged at a position facing the developing device 21 with the photoconductor 20 interposed therebetween, and the image exposing means 26 has an LED array 27 which is generated according to an image signal.
And a SELFOC lens 28 that collects the image light of the LED array 27. A transfer roller 29 is applied with a negative transfer bias voltage V _t . The transfer roller 29 electrostatically attracts and transfers the plus toner 23 of the photoconductor 20 to the recording paper 100. The image forming principle of this apparatus is as follows.

First, the first development will be described. The photoconductor 20 is rotated in the direction of the arrow in FIG. 11, and the developing bias voltage V _b is applied to the elastic developing roller 22 of the developing device 21 as shown in FIG. 12A. In this state, the image exposure means 26 image-exposes the photoconductor 20. At this time, as shown in FIG. 13A, the photosensitive layer 20c of the photoconductor 20 and the elastic developing roller 22 are
Between them, the thin layer formation by the doctor blade 24 and the pressing force of the elastic developing roller 22 are set so that about two toners 23 of about 10 μm exist.

By the imagewise exposure of the photoconductor 20, electron holes are generated in the exposed area, the electrons in the exposed area move to the surface of the photosensitive layer 20c by the electric field, and a large amount of toner 23 is present in the exposed area. Some toner 23 adheres to the non-exposed portion. In this exposed portion, electrons (latent image charge) and toner 23 are bound to the surface of the photosensitive layer 20c by electrostatic attraction,
The toner 23 does not receive the suction force in the non-exposed portion.

As described above, when the one-component toner is used, the distance between the photosensitive layer 20c of the photoconductor 20 and the elastic developing roller 22 becomes small, so that a sufficient voltage is applied to the photosensitive layer 20c and sufficient toner can be attached. .

Next, the second development is performed as shown in FIGS.
Explaining with (B) and (C), the toner image formed by the above-described first development moves to the collecting roller 25 side. As shown in FIG. 13B, the collecting roller 25 is provided on the photosensitive member 20.
In contrast, the bite amount δ is set to 0.1 to 0.5 mm,
The rotation direction is opposite to that of the photoconductor 20, and the peripheral speed is 1.2 to 3.0 times that of the photoconductor 20. Therefore, as shown in FIG. 13C, the collecting roller 25 comes into contact with the photoconductor 20 and a mechanical scraping force is generated to scrape the toner of the photoconductor 20 to remove the toner in the non-exposed portion. Collect.

[0022]

Each of these conventional techniques has the following problems. First, the case of the apparatus of FIG. 9 will be described. Since the image exposure and the development are simultaneously performed in the first developing step, the photocarrier generated in the photoconductor needs to move at high speed. Therefore, the photosensitive layer 1c having high carrier mobility was required. As shown in FIG. 14, the photosensitive layer 1c has a small change with respect to an electric field and exhibits a large carrier mobility even in a weak electric field.

When such a photoreceptor 1 is used, as shown in FIG. 15 (A), at the recording electrode 4 portion (A portion), the photocarriers generated in the photoreceptor move at high speed toward the surface of the photoreceptor. And become latent image charge. Next, in the pooled portion (B portion) of the developer for collecting the background toner, as shown in FIG. 15B, the electrostatic charge 9 moves despite the weak electric field applied to the photosensitive layer 1c.

Therefore, the electrostatic charge 9 on the surface of the photoconductor moves to the conductive layer 1b side of the photoconductor again, and acts so as to weaken the adhesive force of the toner on the surface of the photoconductor. As a result, the amount of toner adhering to the photoconductor is reduced, and the image density is reduced.

In the case of the apparatus shown in FIG. 10, the same photosensitive member 1 as that shown in FIG. 9 is used.
As shown in FIG. 6 (A), electron-hole pairs are generated in the charge generation layer, and positive charges (holes) move through the charge transport layer toward the surface of the photoreceptor 1 by the electric field formed by the power supply 14. To form a latent image charge 18. In addition, negative charges (electrons) flow into the ground.

At this time, even if the polarities of the power source 14 are reversed and a positive voltage is applied to the first developing machine 12, the negative charges (electrons) do not move. This is because the boundary surface between the charge transport layer and the charge generation layer serves as a block layer. That is,
Positive charges can pass through this interface, but negative charges cannot.

Next, in the second developing machine 13 for collecting the toner in the background portion, as shown in FIG. 16B, the toner collecting electric field is applied to the charge transporting layer by the power source 16, so that a slight amount of positive charge is generated. The (latent image charge) 18 moves. Therefore, the latent image charge 18 on the surface of the photoconductor 1 moves again to the conductive layer side of the photoconductor 1 and acts so as to weaken the adhesive force of the toner on the surface of the photoconductor 1. As a result, the amount of toner adhering to the photoconductor 1 is reduced, and the image density is reduced.

In the case of the apparatus shown in FIG. 11, in the second development for collecting the toner in the background portion, a toner collecting electric field is applied by the collecting roller 25 as shown in FIG. 12 (B). Therefore, the latent image charge on the surface of the photoconductor 20 moves to the conductive layer 20b side of the photoconductor 20 again, and acts so as to weaken the adhesive force of the toner on the surface of the photoconductor 20. Therefore, the amount of toner adhering to the photoconductor 20 is reduced, and the image density is reduced.

As described above, the conventional apparatuses shown in FIGS. 9, 10 and 11 all have a problem that the amount of toner adhering to the photoconductor is reduced and the image density is lowered.

It is an object of the present invention to provide an image recording device which can prevent a decrease in image density.

[0031]

In order to achieve the above object, in the present invention, a light-transmitting conductive layer, a photosensitive layer for generating and transporting photocarriers, and the photosensitive layer are divided on a transparent substrate. As described above, an image exposure unit arranged on the transparent substrate side of the photoconductor, using a photoconductor formed by stacking at least a plurality of blocking layers provided on the transparent substrate side of the divided photosensitive layers, Image exposure and first development by a strong electric field and second development by a weak electric field by the developing means arranged to face the image exposing means on the side of the photosensitive layer of the photoconductor.
In an image recording apparatus that performs development at the same time, each of the blocking layers is formed of an amorphous silicon compound, and the composition ratio thereof continuously changes so that the ratio of silicon on the transparent substrate side becomes large. Characteristic configuration (first
Configuration).

Further, on the transparent substrate, a conductive layer which transmits light, a photosensitive layer for generating and transporting photocarriers, and a photosensitive layer which are divided so as to divide the photosensitive layer are provided on the transparent substrate side. An image exposure means disposed on the transparent substrate side of the photoreceptor, and an image exposure means on the photosensitive layer side of the photoreceptor, using a photoreceptor formed by at least laminating a plurality of blocking layers provided. By the developing means arranged facing each other,
In an image recording apparatus that simultaneously performs image exposure and first development with a strong electric field and second development with a weak electric field, each of the blocking layers is formed of amorphous silicon doped with valence electron controlling atoms. A configuration (second configuration) is characterized in that the doping amount is continuously changed so that the doping amount on the transparent substrate side becomes small.

[0033]

In the first structure, each blocking layer is formed of an amorphous silicon compound, and the composition ratio of each blocking layer is continuously changed so that the silicon ratio on the transparent substrate side is increased. . That is, the blocking property of each blocking layer is weak on the transparent substrate side and strong on the surface side. Therefore, the carriers can be run under a strong voltage applied during the first development, but during the second development where a weak electric field is applied, the carriers are less likely to move to the transparent substrate side, and a large number of carriers are retained. As a result, reduction in image density is prevented.

Further, in the case of the second structure, each blocking layer is formed of amorphous silicon doped with atoms for controlling valence electrons, and the doping amount of the blocking layer is smaller on the transparent substrate side. Is continuously changing. Also in this case, the carrier can be moved in the first development, but a large number of carriers are held in the second development.
The decrease in image density is prevented.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

1 to 5 show a first embodiment.

3A and 3B are structural explanatory views of various image recording apparatuses of this embodiment. FIG. 3A uses a photosensitive drum and FIG. 3B uses a photosensitive film. First, FIG. 3 (A)
The apparatus 31 will be described. Reference numeral 31 is a photosensitive drum (photosensitive member), which is formed on a transparent substrate of a quartz tube having a thickness of 5 mm by ITO.
A transparent conductive layer of (indium oxide) vapor deposition film is provided, and a photosensitive layer mainly composed of amorphous Si (hereinafter abbreviated as a-Si: H) is further formed.

The application of a photoconductor containing an a-Si: H film as a main component has already been proposed by the present applicant (Japanese Patent Application No. 63-63).
No.-52725, filed on March 8, 1988). In the present invention, the photosensitive layer of the above-mentioned application is made into a thin film or a multilayer, and the blocking property between them is changed (s-
By continuously changing the composition ratio of Si: H so that the ratio of silicon on the transparent substrate side becomes large), a photosensitive member adapted to the above recording system is provided.

FIG. 1 shows a detailed cross section of the photoconductor 200 used in the present invention. In the figure, 201 is a transparent substrate, 202 is a transparent conductive layer, 203 is a photosensitive layer, the photosensitive layer 203 is divided into a plurality of layers, and a blocking layer 204 is formed on the transparent substrate side of each divided photosensitive layer. ing. Figure 1 (A)
Shows an example in which the photosensitive layer is divided into two layers, as shown in FIGS. 1 (B) and 1 (C).
Shows an example in which the photosensitive layer is divided into five layers, respectively, and FIG.
In the cases of (A) and (B), the surface layer 205 is formed.

FIG. 5 shows a method of forming a film on a photoreceptor having such a structure.
Will be described. First, a transparent substrate 201 having ITO deposited as a transparent conductive layer is set in the vacuum container 102. Then, the inside of the vacuum container 102 is evacuated to 10 ⁻⁷ Torr by an oil diffusion pump or the like (not shown). Next, the transparent substrate 201 is rotated at a constant speed by the motor 103, and is heated to 200 to 300 ° C. (desirably 250 ° C.) by the heater 104.

Here, the pumps are mechanical booster pump (PMB) 105 and rotary pump (RP) 106.
And the material gas is transferred from the cylinders 107 ₁ and 107 ₃ through a flow rate controller and a valve (not shown) to the vacuum container 102.
Introduce inside. The pressure of this gas is made constant (10 ^-2 to several Torr) by adjusting an exhaust valve (not shown). After this,
High-frequency power is applied to the discharge electrode 109 from the RF power source 108 to cause glow discharge. The material gas is decomposed and excited by this plasma energy, and a blocking layer is formed on the transparent substrate 201.

In the blocking layer, a gas such as C ₃ H ₈ is controlled by a flow rate controller so that X of a-Si _x C _1-x : H can be obtained.
Change continuously. After reaching the required film thickness, the high frequency power from the RF power supply 108 is stopped, and the film formation is stopped.
After exhausting the material gas involved in forming the blocking layer, the gas necessary for forming the photosensitive layer is introduced. After keeping the gas pressure constant, the discharge electrode 109 is supplied from the RF power source 108.
High-frequency power is applied to generate a blow discharge, and the film is similarly formed.

After the required film thickness is obtained, the film formation is stopped and the next film formation of the blocking layer is started. This is repeated, and after the film formation of the final photosensitive layer is completed, the same surface layer is formed as necessary, and the film formation is completed. After the film formation is finished, the heating power supply is stopped and cooling is performed. Further, the inside of the vacuum container 102 is also purged, and after the substrate temperature has dropped to about room temperature, the photoconductor is taken out from the inside of the vacuum container 102.

Tables 1 to 6 show various examples of film formation by the above method. Tables 1 to 3 are for the photosensitive layer 2-layer type having the constitution of FIG. 1 (A), and Tables 4 and 5 are for the photosensitive layer 5 layer type (having a surface layer) of the constitution of FIG. 1 (B). Table 6 shows the five-layer photosensitive layer type (no surface layer) of FIG. 1 (C).

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

Further, the material gas of the blocking layer in Table 3 was changed to
Si₂H₆Instead of SiF_FourBy using a-Si_x
C_1-x: F: H film may be formed. For this film formation
C as the material gas for the blocking layer₃H₈Instead of C
F_FourBy using a-Si _xC_1-x: Form F film
Is also good. When a high voltage is applied during the above film formation
Is 10^-Fivecm²/ V ・ S carrier velocity is opposite
10 when a low voltage is applied^-7cm²/ V ・ S or later
The film was designed and formed so as to be below. In addition, S source
i₂H₆Was used, but SiH_FourBut good.

Photosensitive drum 31 obtained as described above
Has a transparent conductive layer connected to the ground and is driven by a photoconductor power system to rotate in the direction of the arrow. A magnetic brush developing machine 32 (the same as the magnetic brush developing machine 2 in FIG. 9) is arranged at a position facing the surface of the photoconductor drum 31. The details of the magnetic brush developing machine 32 are as shown in FIG. 4, and the magnet roller 32a provided inside the sleeve 32b is rotatable.

On the surface of the sleeve 32b, a strip-shaped recording electrode 34 made of copper foil insulated with a polyimide film 33 is attached. Magnetic brush developing machine 32 as described above
And a developer 3 in which a conductive carrier and an insulating toner are mixed.
5 is filled, and this is conveyed by the rotation of the magnet roller 32a in the arrow direction of FIG.

In the case of the film formation according to the above Tables 1, 2, and 5,
Since the photosensitive layer is a weak N type, a negative voltage is applied to the recording electrode 34 by the first power source 36. This voltage is -10
0 to -600V is suitable. A positive voltage is applied to the sleeve 32b by the second power source 37. This voltage is suitably 0 to + 100V. On the other hand, in the case of film formation according to the other Tables 3, 4, 6 and the like, a positive voltage is applied to the first power supply 36 and a negative voltage is applied to the second power supply 37.

An image exposing means 38 (similar to the image exposing means 8 in FIG. 9) is arranged at a position facing the magnetic brush developing machine 32 with the photoconductor drum 31 interposed therebetween. The image exposure means 38 is an LED that emits light according to an image signal.
The array 38a and the self-occ lens array 38b that condenses the image light of the LED array 38a are configured.

Reference numeral 39 is a toner image formed on the photosensitive drum 31, and 40 is a recording paper. 41 is a conductive rubber roller for transfer, which is supplied with a voltage (+200 to +600) by a power source 42.
V) is being applied. Reference numeral 43 denotes a toner image electrostatically transferred onto the recording paper 40, which is recorded by the heat roller fixing device 44.
It is fixed at 0, and becomes a semi-permanent recorded image 45. 46 is a residual toner image remaining on the photosensitive drum 31 after transfer, 47
Is a static elimination light source for removing the latent image charge of the residual toner 46, 48
Is a toner image that has been destaticized and lost its electrostatic restraint force.

Next, the image recording procedure will be described. At the time of recording, the photosensitive drum 31 is rotated in the direction of the arrow, and the developer 3
5 is conveyed in the direction of the arrow to form a developer pool, and the photosensitive member is imagewise exposed by the image exposing means 38 in a state where the recording electrode 34 applies a voltage to the sleeve 32b.

As a result, photocarriers are generated in the photosensitive layer, and the majority of holes (electrons in the case of film formation according to Tables 3, 4, and 5) are blocked as shown in FIG. 2 (A). It moves across the layer toward the surface of the photoconductor to become a latent image charge. Therefore, in the exposed portion, the electrostatic capacity of the photosensitive layer apparently increases, so that the amount of adhered toner increases, and a toner image with a certain degree of contrast is formed between the exposed portion and the non-exposed portion.

Next, in the developer pool, a reverse voltage is applied to the sleeve 32b, and excess toner in the non-exposed area is collected in the developing machine 32 by electrostatic force. At this time, the toner in the exposed portion is also slightly collected.

However, the latent image charge in the exposed area has a relatively low reverse voltage and is difficult to pass through the blocking layer. Moreover, since the blocking property on the surface layer side is particularly strong,
As shown in FIG. 2B, most of the latent image charges are retained in the photosensitive layer on the surface layer side. Therefore, the electrostatic restraint force between the latent image charge and the toner charge is held, and most of the toner remains on the photosensitive drum 31, and the toner image 39 is formed. Next, the toner image 39 is electrostatically transferred onto the recording paper 40 using the transfer roller 41. The transferred toner image 43 is fixed by a fixing device 44.
The image is fixed on the recording paper 40 by the semi-permanent recording image 45.
Is obtained.

On the other hand, the residual toner image 46 remaining on the photosensitive drum 31 after the transfer is discharged by the discharging light source 47. The removed toner image 48 is transferred to the magnet roller 32.
a magnetic force, scraping of the developer 35, and sleeve 32b
It is recovered by the electrostatic force due to the applied voltage and is reused. The next image formation is performed at the same time when the residual toner image 48 is collected. Thus, collecting the residual toner image 48 and performing the next image formation at the same time does not cause any problems because the image exposing means and the developing device 32 are opposed to each other with the photosensitive drum 31 interposed therebetween.

As described above, in this example, the multilayer structure of the amorphous Si photoconductor is used. Then, a blocking layer is sandwiched between the photosensitive layer and the photosensitive layer so that the blocking property of the blocking layer allows the carrier to penetrate through the blocking layer at the high electric field of the first development and restrains the carrier at the low electric field of the second development. By making it possible, clear printing with high printing density can be obtained. Such blocking property is obtained by changing the composition ratio of each booking layer of the amorphous Si compound to the Si on the substrate side.
It is provided by continuously changing so that the ratio of is increased.

Moreover, according to this example, a simple recording process with a small number of steps is performed without using a corona discharger that generates ozone harmful to the human body and requires a high voltage, or a Carlron process with a large number of steps. Since the device is used, the device becomes smaller.

In the above description, the example in which the photoconductor drum 31 is used as shown in FIG. 3A has been described, but the same effect can be obtained by using the photoconductor film (photoconductor) 49 as shown in FIG. 3B. Of course, Photoconductor film 49
Is a 100 μm thick transparent substrate of polyethylene terephthalate, on which a transparent conductive layer of an ITO vapor deposition film is provided, and a photosensitive member containing amorphous Si as a main component similar to the case of the above-mentioned drum is formed. is there.

Further, as the image recording process, the example in which the residual toner is collected in the magnetic brush developing device has been described in the above description, but the process of removing the residual toner by a brush cleaner, a blade cleaner or the like may be used, and the transfer process may be performed. The corona transfer method may be used instead of the roller transfer method.
As the developer, a conductive one-component developer can also be used in addition to the two-component developer.

Furthermore, the present invention can be applied not only to the image recording apparatus such as the printer as in the above-mentioned embodiment but also to the display apparatus for directly seeing the toner image on the photosensitive member without providing the transfer step.

A second embodiment is shown in FIGS. 6 and 7.

FIG. 6 is an explanatory view of the structure of the image recording apparatus of this example, in which 51 is a photosensitive drum. The photoconductor drum 51 is similar to the photoconductor drum 31 of the previous example, and has the structure shown in FIG. 1 of the previous example. The film formation of the photoconductor is also performed under the same conditions (Table 1 to Table 6) by the same apparatus (the apparatus of FIG. 5) as the previous example. This photosensitive drum 51 is
The transparent conductive layer is connected to the ground and driven by a power system (not shown) to rotate in the arrow direction.

One side (inside) with the photoconductor drum 51 interposed therebetween.
Is provided with an image exposure unit 52 (similar to the image exposure unit 38 of the previous example), and on the other side (outside), a first magnetic brush developing machine 53 facing the image exposure unit 52 and on the downstream side thereof. And a second magnetic brush developer 54 located therein. The first and second developing machines 53 and 54 are shown in FIG.
It is similar to the first and second developing machines 12 and 13 of No. 0, and is composed of an inner magnet roller and an outer sleeve, and the sleeve is configured to be rotatable.

A first recording voltage having a polarity opposite to the polarity of the charges of the photosensitive layer of the photosensitive drum 51 is applied to the first magnetic brush developing device 53 by the power supply 55. The first developing machine 53 is filled with a developer 56 in which a conductive carrier and an insulating toner are mixed, and the developer 56 is conveyed by the rotation of the sleeve. A second recording voltage having a polarity opposite to that of the first recording voltage is applied to the second developing device 54 by a power source 57. The second developer 54 is filled with the same developer 58 as that filled in the first developer 53, and the developer 58 is conveyed by the rotation of the sleeve.

Reference numeral 59 is a toner image formed on the photosensitive drum 51, and 60 is a recording paper. 61 is a conductive rubber roller for transfer, to which a voltage is applied by a power source 62. 6
A toner image 3 is electrostatically transferred onto the recording paper 60, and is fixed on the recording paper 60 by the heat roller fixing device 64 to form a semi-permanent recorded image 65. 66 is the residual toner image after transfer, 6
Reference numeral 7 denotes a charge eliminating light source for removing the latent image charge of the residual toner image 66,
Reference numeral 68 denotes a toner image that has lost its electrostatic restraint force due to static elimination.

At the time of image recording, as in the case of FIG. 10, the image exposure means 52 performs image exposure on the photosensitive drum 51, and the first and second developing machines 53 and 54 perform first and second exposure.
Develop. As a result, the toner image 59 is formed on the photosensitive drum 51. Next, the toner image 59 is electrostatically transferred onto the recording paper 60 using the transfer conductive rubber roller 61, and is fixed by the fixing device 64 to obtain a semi-permanent recorded image 65.

On the other hand, the residual toner image 66 remaining on the photosensitive drum 51 after the transfer is discharged by the discharging light source 67,
It is collected in the developing machine and reused. The next image formation is performed simultaneously with the collection of the residual toner image. Such simultaneous collection of the residual toner image and the next image formation is performed because the image exposure means 52 and the first and second developing machines 53 and 54 are opposed to each other with the photoconductor drum 51 interposed therebetween. There is no problem.

Also in the case of this example, as in the previous example, amorphous Si is used.
The multi-layer structure of the photoconductor is used. Then, a blocking layer is sandwiched between the photosensitive layer and the photosensitive layer so that the blocking property of the blocking layer allows the carrier to penetrate through the blocking layer at the high electric field of the first development and restrains the carrier at the low electric field of the second development. By making it possible, clear printing with high printing density can be obtained.

Such blocking property is due to the amorphous Si.
It is imparted by continuously changing the composition ratio of each blocking layer of the compound so that the ratio of Si on the substrate side becomes large. 7A and 7B are explanatory views of carrier behavior in the photoconductor, and FIG. 7A shows the first developing time.
(B) shows the time of the second development.

In the above description, the photosensitive member is used in the form of a drum, but it is needless to say that the same effect as above can be obtained by using it in the form of a film. In addition, the residual toner can be removed by a cleaner, corona transfer can be used for transfer, a conductive single-component developer can be used as a developer in addition to the two-component developer, and it can be applied to a display device. is there.

In the above description, the example applied to the conventional apparatus of the type shown in FIGS. 9 and 10 has been described.
The present invention can be applied to a device of this type and the same effect can be obtained. Although the structural explanatory view of the apparatus in this case is omitted, the configuration of the photoconductor used and the film forming procedure are the same as those in the first and second embodiments. 8A and 8B are explanatory diagrams of the behavior of the carrier in the photoconductor in this case. FIG. 8A shows the first development and FIG. 8B shows the second development.

In the above description, an example in which an amorphous silicon compound is used as the blocking layer for partitioning the photosensitive layer has been described, but it is also possible to use amorphous silicon doped with valence electron controlling atoms as the blocking layer. it can.
In this case, the doping amount of each blocking layer is continuously changed so that the doping amount on the transparent substrate side (the side opposite to the photosensitive layer) becomes small. This allows the carrier to travel during the first development, but allows a large number of carriers to be retained during the second development, thus preventing a decrease in image density.

As atoms for controlling valence electrons, there are II of the periodic table.
Boron, which is an atom belonging to Group I, or phosphorus, which is Group V in the periodic table, can be used.

Tables 7 to 10 show various film forming examples using such a blocking layer. Tables 7 and 8 are for a two-layer photosensitive layer (configuration of FIG. 1A), and Table 9 is for a five-layer photosensitive layer (having a surface layer of the configuration of FIG. 1B). Is a five-layer photosensitive layer (no surface layer having the structure of FIG. 1C).

[Table 7]

[Table 8]

[Table 9]

[Table 10]

The photoconductor in which the doping amount of each blocking layer is changed as described above can be applied to each type of image recording apparatus as shown in FIGS. 9, 10 and 11, and the amorphous silicon compound of each blocking layer can be used. The same effect as in the above-described case in which the composition ratio of is continuously changed is obtained.

[0076]

As described above, according to the present invention, the image exposure, the first development by the strong electric field, and the second development by the weak electric field are performed by the image exposing means and the developing means which are opposed to each other with the photoconductor interposed therebetween. It is possible to prevent a decrease in image density, which has been a problem in the past, when performing the development together, and it is possible to obtain a clear toner image with a high printing density.

[Brief description of drawings]

FIG. 1 is a detailed sectional view of a photosensitive member used in the present invention.
(A) shows a two-layer type, and FIGS.
A layer type is shown.

FIG. 2 is an explanatory view of the behavior of the carrier in the photoconductor of the first embodiment of the present invention, FIG. 2 (A) shows at the time of the first development,
FIG. 2B shows the time of the second development.

3A and 3B are structural explanatory views of various image recording apparatuses according to the first embodiment of the present invention, FIG. 3A shows a structure using a photosensitive drum, and FIG. 3B is a structure using a photosensitive film. It shows what was there.

FIG. 4 is a perspective view of the developing machine of FIG.

FIG. 5 is a structural explanatory view of a film forming apparatus according to a first embodiment of the present invention.

FIG. 6 is a structural explanatory diagram of an image recording apparatus according to a second embodiment of the present invention.

FIG. 7 is an explanatory view of the behavior of the carrier in the photoconductor of the second embodiment of the present invention, FIG. 7 (A) shows the time of the first development,
FIG. 7B shows the time of the second development.

8A and 8B are explanatory diagrams of the behavior of the carrier in the photoconductor when the present invention is applied. FIG. 8A shows the time of the first development and FIG. 8B shows the time of the second development. There is.

FIG. 9 is a side view showing an outline of the structure of a conventional image recording apparatus.

FIG. 10 is a side view showing an outline of the structure of another conventional image recording apparatus.

FIG. 11 is a side view showing an outline of the structure of another conventional image recording apparatus.

12 is an explanatory view of the behavior of a photo carrier in the photoconductor in the apparatus of FIG. 11, FIG. 12 (A) shows the first development,
FIG. 12B shows the time of the second development.

13 is an explanatory diagram of a developing process of the apparatus of FIG. 11, FIG.
3A shows the toner layer existing state, FIG. 13B shows the collecting roller pressure contact state, and FIG. 13C shows the toner scraping by the collecting roller.

FIG. 14 is a characteristic explanatory diagram of a photoconductor that has been conventionally used.

15A and 15B are explanatory diagrams of the behavior of the carrier in the photoconductor in the apparatus of FIG. 9, and FIG. 15A shows the time of the first development.
(B) shows the time of the second development.

16 is an explanatory view of the behavior of a photo carrier inside the photoconductor in the apparatus of FIG. 10, FIG. 16 (A) shows the time of first development,
FIG. 16B shows the time of the second development.

[Explanation of symbols]

 31, 51 Photoreceptor Drum (Photoreceptor) 32, 53, 54 Magnetic Brush Developing Machine (Developing Means) 38, 52 Image Exposure Means 49 Photoreceptor Film (Photoreceptor) 200 Photoreceptor 201 Transparent Substrate 202 Transparent Conductive Layer 203 Photosensitive Layer 204 blocking layer

Claims (2)

[Claims] 1. A conductive layer which transmits light on a transparent substrate,
It is formed by stacking at least a photosensitive layer having a function of generating and transporting photocarriers and divided into a plurality of layers by a blocking layer, and the blocking layer is provided on the transparent substrate side of each divided photosensitive layer. Using a photoconductor, the image exposure means arranged on the transparent substrate side of the photoconductor and the developing means arranged on the photosensitive layer side of the photoconductor opposite the image exposure means, First development by electric field,
In an image recording apparatus that simultaneously performs second development with a low electric field, each of the blocking layers is formed of an amorphous silicon compound, and the composition ratio of the blocking layers is continuously increased so that the silicon ratio on the transparent substrate side becomes large. An image recording device characterized by changing. 2. A conductive layer which transmits light on a transparent substrate,
It is formed by stacking at least a photosensitive layer having a function of generating and transporting photocarriers and divided into a plurality of layers by a blocking layer, and the blocking layer is provided on the transparent substrate side of each divided photosensitive layer. Using a photoconductor, the image exposure means arranged on the transparent substrate side of the photoconductor and the developing means arranged on the photosensitive layer side of the photoconductor opposite the image exposure means, First development by electric field,
In an image recording apparatus that simultaneously performs second development with a weak electric field, each of the blocking layers is formed of amorphous silicon doped with atoms for controlling valence electrons, and the doping amount is the doping amount on the transparent substrate side. An image recording apparatus characterized by continuously changing so that