JPS59176A - Method and device for electrophotography - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic method and apparatus, and more particularly to a single-child photographic method and apparatus that prevents developer from scattering from a photoreceptor to the surrounding area.

In recent years, laser beam printers based on electrophotography have been widely used as terminal printers for computers, as they enable high-speed image processing.

This system uses a modulated laser beam as a terminal signal instead of the optical system of a conventional electrophotographic copying machine to obtain high-quality images through a process similar to that of a copying machine.

[7] In this type of apparatus, a laser beam modulated with an information signal is irradiated onto a photoreceptor to form a corresponding latent image, and an image scanning method is generally used for this laser beam irradiation. This image scanning method is a method in which a laser beam is irradiated on portions corresponding to information signals such as characters, but the laser beam is not irradiated on the background other than the information signal. In contrast to this method, there is a background scanning method in which the background portion is irradiated with a laser beam. However, in contrast to the post-consideration method, the image scanning method has been put into practical use because it does not leave scan marks on the background image and there is no risk of information signals flying away.

When the image scanning method described above is performed in an apparatus using a Carlson-type electrophotographic photoreceptor, the image scanning method is performed by reversal development, as shown in image C. That is, using a developer loaded with the same polarity as the charge on the background of the latent image on the photoreceptor, the partial pressure of the latent image whose surface charge on the photoreceptor is attenuated by laser beam irradiation is given as (-1). The developed image is then transferred to a transfer material and used.

FIG. 1 shows a layout diagram of the main processes around the photosensitive drum of such a conventional laser beam printer. A photosensitive drum 1 has a photosensitive layer 2 and a grounded conductive substrate 3f.

4 is a primary charger, and 5 is a laser irradiation light. The other is a developing device, which is equipped with a doctor blade 7 and a magnetic roller 8. 9 is a developer. lO is a pre-transfer charger, 11
- is a transfer paper guide, and 1 and 12 are transfer chargers. 13 is a cleaner, including a rubber blade 14° and a magnet roller 15. Screw +6. It includes a housing 17 and the like. 1
Next, the surface of the photosensitive drum 1 is uniformly charged by the charger 4. Next, the photosensitive drum 1 is exposed to laser irradiation light 5 having an intensity corresponding to the terminal signal based on the image scanning method described above. An electrostatic latent image is formed on the photosensitive drum l in response to this irradiation light. Subsequently, the photosensitive drum 1 is transferred to a developing device 6.
The latent image on the drum surface is visualized through the position. Thereafter, a pre-transfer charger 10 applies corona discharge to the developed image.

Thereafter, the developed image is transferred by a transfer corona discharger 12 onto a transfer paper (not shown) guided by a transfer guide 11. The untransferred developer remaining on the drum 1 is removed from the surface of the drum 1 by the rubber blade 14, is attracted to the magnet roller 15, and is further removed by the screw 1.
6 and is housed in a toner collection box (not shown) that forms part of the housing 17. The drum l thus cleaned is sent to the first step, the primary belt core process, and is used repeatedly.

An example of a copy created in this way is schematically shown in FIG. 1B is a copy, and 19 is a visualization.

The image 19 is made of a black developer and is fixed and permanently recorded on the copy 19. As mentioned earlier, in the laser irradiation process, an image scanning method is adopted in which the laser beam is irradiated to the part corresponding to the visible image 19 in copy image 8, and the background other than the visible image 19 is not irradiated with laser light. There is.

FIG. 2 is an explanatory diagram of temporal changes in the photoreceptor surface potential due to latent image formation in the above-mentioned apparatus. The vertical axis shows the surface potential (V), and the horizontal axis shows time.

Here, an example is shown in which amorphous silicon is used for the photosensitive layer 2 of the photosensitive drum 1, and primary charging is performed with 4Vi negative polarity. The surface potential obtained by the primary charging 4 is converted into a latent image potential of about 450 V by the difference between dark attenuation and bright attenuation due to laser irradiation, that is, contrast, and is 1%.

FIG. 4 schematically shows the developed state of the latent image, with the vertical axis being the photoreceptor surface potential, and the horizontal direction being the direction in which the photoreceptor surface spreads.

Background■. Toner does not adhere to the negative potential part of the laser irradiation part near the ground potential ■1. However, since this type of apparatus performs reversal development as described above, the developer retention power of the latent image formed on the surface of the photoreceptor is weak. Further, an electric field is formed between a member adjacent to the photoreceptor surface, such as a developing device, a transfer guide, a cleaner, and the photoreceptor surface, in a direction that causes the developer on the photoreceptor surface to separate. This caused developer scattering.

FIG. 5 is a schematic diagram explaining this phenomenon.

The figure conceptually shows lines of electric force generated between a grounded conductor near the drum 1, for example, the cleaner casing 17 and the surface of the drum 1. Since the surface of the drum 1 is negative as a whole, the lines of electric force are directed toward the surface of the drum 1 from the tip 17 of the conductor, and there are particularly dense lines of electric force at the tip. Therefore, the toner on the surface of the drum 1 is subjected to a suction force such as the opening end of the cleaner housing 17. Then, it separates from the surface of the photoreceptor and scatters. Therefore, it causes contamination inside the aircraft.

In order to improve the retention of developed images using such an image scanning method, the following electrophotographic method can be used.

Using a photoreceptor whose basic structure is a conductive layer, a photoconductive layer, and an insulating layer, it is primarily charged with a predetermined polarity and is irradiated with a light beam that is modulated using an image scanning method that turns on the information part based on an information signal. onto the surface of the photoreceptor. At the same time as this light beam irradiation, a sufficient voltage was applied to cause secondary charging of opposite polarity. This is a method in which a latent image is formed by applying it using a corona discharge means or the like and then uniformly exposing it to light.

In this case, the bright part (information part) of the formed latent image has a high potential of secondary charge polarity. Therefore, by selecting a developer charged with the same polarity as the primary charge, development without developer scattering can be achieved.

In the darker area, an electric field of opposite polarity is generated between the surface insulating layer and the bottom conductive layer. A history remains in this reverse polarity electric field. For this reason,
When images are repeatedly formed, sufficient charge is not accumulated in the hysteresis portions, resulting in white portions in normal development, while abnormally dark portions occur in the above-mentioned reversal development. Therefore, it has been difficult to use the above-mentioned electrophotographic method in which such images may occur.

Therefore, when using such a photoreceptor, in order to prevent the generation of a strong reverse polarity electric field that would cause history on the photoreceptor, reverse polarity is applied in the secondary band process at the same time as the light beam irradiation in the method described above. It was decided to carry out the method by weakening the applied voltage, or by using AC biased with DC bias instead of applying a reverse polarity voltage. In the case based on these methods, when the light beam irradiation area (bright area) fc development is performed, developer scattering is inevitable as in the above-mentioned Carlson method.

In addition, both methods have the disadvantage that if the retention force of the developed images on the photoreceptor is weak, the transferred image is likely to be disturbed during transfer. This disturbance of the transferred image means that when the developed images on the photoreceptor are transferred onto the transfer material, the developed images on the photoreceptor are transferred onto the transfer material before the transfer material comes sufficiently close to or in close contact with the photoreceptor. Because of this, the developer will fly to a nearby position that is shifted from the position of the transferred image that will be formed on the transfer material in close proximity or close contact with the transfer material.
This is a phenomenon that disturbs the transferred image.

In particular, when based on the above-mentioned Carlson method, when irradiated with a normal laser beam, the photoreceptor beam irradiation area (bright area)
Since the charges are not completely annihilated, charges of the same polarity as the dark areas remain in the bright areas as well.

For this reason, the developer charged with the same polarity applied to the bright area is subject to the repulsive force of the residual charge, which tends to cause the aforementioned developer scattering and also tends to cause disturbances in the transferred image. In addition, I of the latent image forming method using a photoreceptor having the above-mentioned basic structure of three layers.
Even in the case of clumping, in the halftone part, there was a part where the charge of the same polarity as the dark part remained, and this gave a repulsive force to the developer applied to the halftone part.

Therefore, in these processes, when a bright area latent image in which the charge of the same polarity as the primary charge remains is formed and developer is applied to the bright area (reversal development), developer scattering occurs as in the above-mentioned Carlson method. It also became easier to cause disturbances in the transferred image.

An object of the present invention is to provide a new and improved electrophotographic method and apparatus.

An object of the present invention is to provide an electrophotographic method and apparatus that performs reversal development and does not cause developer scattering.

A further object of the present invention is to provide an electrophotographic method and apparatus for forming reversal images without disturbance of transferred images during transfer.

The present invention provides at least a method for obtaining an image by irradiating optical information onto a photoreceptor having a conductive substrate, forming a corresponding electrostatic latent image, performing reversal development, and transferring the developed images onto a transfer material. The details of the present invention will be described in detail below. An example will be explained with reference to the drawings.

FIGS. 6(a) to 6(d) are schematic diagrams illustrating a specific example process based on the present invention.

A is a photoreceptor having a structure in which a photoconductive layer a is provided on a conductive substrate a2. As the photoconductive layer a, ZnO, Se
, CdS, amorphous silicon, organic photoconductive material (OPC), and other desired photoconductive materials may be used singly or in combination.

The conductive substrate a2 is made of a metal material such as aluminum. The illustrated example is a structure in which amorphous silicon is provided on an aluminum substrate.

The first step (FIG. 6(a)) is a charging step in which the surface of the photoreceptor is uniformly charged in a negative direction by a corona discharger C8.

The tag is electric saliva.

On the conductive substrate a of the photoreceptor, charges of opposite polarity (positive) are induced in response to the charges on the surface of the photoreceptor.

Further, a predetermined voltage having a polarity opposite to that of the corona discharge is applied to the conductive substrate a2V of the photoreceptor. This applied voltage is sufficient to adsorb the developer, as will be described later, and the reverse polarity 'h pressure, which lowers the underlying surface potential to near zero, is good. This promotes charging,
It also has the effect of reducing the charging load.

The second culm (FIG. 6(b)) is a light information irradiation process. In this process, light carrying information is irradiated onto the surface of the photoreceptor using an image scanning method. For information light irradiation, in addition to light beams such as laser beams CR and T, a normal original, a matacro film, etc. are used.

The figure shows the case of a transmission type negative image original O.

In the bright area of the photoreceptor surface, the resistance of the photoconductive/electrical layer a1 decreases due to light irradiation, and the charge on the photoreceptor surface rapidly decreases. However, in the case of normal light irradiation, some charge remains. In the figure, this state is schematically shown by a pair of charges of opposite polarity. There is no significant change in the charge state in the dark area of the photoreceptor.

The third step (FIG. 6(C)) is a developing step.

In this step, an electrostatic latent image formed on the surface of the photoreceptor in response to the irradiation of optical information is developed with a negatively charged developer T.

As shown in the figure, the developer T is used, and the dark area with the same polarity charge (J))
It does not adhere to the surface, but selectively adheres to the bright area (L) where there is substantially no charge of the same polarity. In this way, reversal development is accomplished.

The developer T on the surface of the photoreceptor is powered by a power source E. From conductive substrate a, V
C is sufficiently retained on the photoreceptor surface by the applied reverse polarity voltage. Further, by applying a bias in this manner, the electric field formed between the members whose side is hot (photoreceptor) does not cause detachment of the developer, but on the contrary, it suppresses it. Therefore, the developer does not scatter around.

The fourth step (FIG. 6(d)) is a transfer step.

In this step, the transfer material P is brought sufficiently close to or in close contact with the surface of the photoreceptor, and a transfer corona discharge is applied from the back side of the transfer material P by a transfer corona discharger C1 to effect the transfer. E! is a power source that applies a voltage having a polarity opposite to that of the developer T to the transfer corona discharger. In the transfer process, a voltage with a polarity opposite to that of the developer is applied from the power source Eo to the conductive substrate a of the photoreceptor (17), so that the transfer material is kept sufficiently close to or in close contact with the surface of the photoreceptor to complete the entire transfer operation. There is no risk of the developer moving to the transfer material before it starts. Therefore, there is no fear of disturbance of the transferred image, and good transfer is achieved.

Furthermore, when the photoreceptor is used repeatedly, an IJ process is performed to remove the developer remaining on the surface of the photoreceptor. The agent adsorbs 'tlj river (said power source)]. Apply with (
~Continuing is valid.

After the cleaning is completed, the photoreceptor LL1 is subjected to the above-mentioned steps repeatedly.

In the method of the present invention, applying a bias to the photoreceptor conductive substrate in the latent image forming step has the effect of easily forming the band 'ktr' as described above. Of course, the present invention also prevents the scattering of the drug.
For this purpose, a bias may be applied to the conductive substrate of the photoreceptor at least after the developer is applied onto the photoreceptor until the transfer step, but no bias may be applied during other steps. good. In the case of a photoreceptor that moves endlessly, it is sufficient to divide the conductive substrate and apply a bias only to the section described above.

Hereinafter F1, a specific example device based on the above process will be explained.

FIG. 7 shows an exemplary device according to the invention.

Components common to those of the conventional example shown in the first drawing are given the same symbols. In the illustrated example, a magnetic component developer is used as the developer 9. This is because, compared to two-component developers, they are superior in that they do not suffer from deterioration due to long-term use or density fluctuations due to oversupply or defective toner.

Of course, a two-component developer can also be used in the present invention. The magnetic component developer is placed on the magnetic roller 8 to a uniform thickness by the doctor blade 7, and then placed on the magnetic roller 8 by air force at the closest point between the drum l and the magnetic roller 8. A second developer is attracted to the latent image area to be developed. This is V. The fine particles (hereinafter referred to as dotoner) constituting the developer are brought into constant polarity by contact with the magnet roller 8, doctor blade 7, etc.
This is because an appropriate bias voltage is applied to the magnet roller 8.

The difference from the conventional example shown in FIG. In [7], the conductive IL substrate 3 of the photosensitive drum 1 is maintained at a potential opposite to the discharge polarity of the primary charger 4, that is, the opposite polarity to the charge polarity of the developer 9, and the primary charger 4 is
charging process, laser light irradiation (5) process, developing device 6
The developed image is transferred through a reversal development process by a corona discharger 12.
A step of transferring the image onto a transfer material is performed. Furthermore, even while the image forming cycle is repeated after the cleaning process, the conductive substrate 3 is maintained in the above-mentioned state by the same bias power source. The bias power supply 21 and the drum board 3 are connected by a slip ring (not shown) provided on the drum rotation shaft, and the drum board 3 is connected by a drum flange (not shown) made of an insulator, etc. Electrically insulated from the machine body.

FIG. 8 shows the behavior of the surface level of the photosensitive drum 10 during the formation of an 871 latent image. In this case, the bias power supply 21 maintains the contrast potential of the three latent images on the substrate at a bias of +500 cm, which is slightly larger than the contrast potential of -1450 cm, at about 711.

During the radar light irradiation process, the surface potential of the photosensitive drum, which has become uniformly banded due to the primary charging and is near O■, is
Depending on the intensity of the laser, the bright area potential changes due to the difference between bright attenuation and dark attenuation ■1. to the dark potential VD.

As mentioned above, τ21j,': I In the case of the conventional example, the inter-dark potential ■
,.

■Compared to the negative polarity of both, the light area potential ■ and the dark area potential ■. The difference is that both have glass polarity.

FIG. 9 conceptually shows the relationship between developed toner and surface potential. The difference from FIG. 4 is that since the surface of the drum 1 corresponding to the bright area has a surface potential of opposite polarity to that of the toner, the adsorption force of the toner to the drum 1 is improved;
Even in the dark part of the back reed, there is a surface potential with the opposite polarity to that of the toner (
The surface charge is of the same polarity as the toner). The latter is connected to the ground conductor (
For example, the direction of the energetic lines of force between the cleaner casing 17) and the surface of the drum 1 is oriented in the opposite direction to the conventional direction, thereby having the effect of forcing the negatively charged toner onto the drum.

In this way, the conventional phenomenon of toner detachment and scattering from the surface of the drum 1 does not occur at all, and fogging on the final copy and contamination inside the machine are solved.

FIG. 11 shows the behavior of the surface potential of the photosensitive drum 1 during formation of a latent image when the potential of the conductive substrate 3 is maintained at a bias potential smaller than the contrast potential of the latent image in the apparatus shown in FIG. In this case, the bright area potential VL has a polarity opposite to that of the toner, which is the same as in the previous embodiment, but the dark area potential VD corresponding to the background has a polarity opposite to that of the toner. The advantage of such a latent image is that the application of a DC bias voltage to the magnetic roller 8 to prevent background fog, which is normally necessary in the developing process, can be omitted. In this case, the direction of the electric lines of force between the ground conductor near the drum 1 and the surface of the drum 1 is as shown in FIG.
) is slightly smaller (e.g., about H) than the value of the conventional latent image contrast 'neighboring'.
The tortoise force line density IW is gradually coarser than that of the conventional example, and does not cause toner angle number.

Figures 12(1)-(e) illustrate different embodiments of the electrophotographic method according to the present invention.

The illustrated method includes a conductive substrate 8, a photoconductive layer b2, an insulating layer b
3, and a developer adsorption voltage is applied to the conductive substrate b1 of this photoreceptor at least after the development step and during the transfer step.

As the photoconductive layer of the photoreceptor, ZnO is used as in the above example.
, Se, CdS, etc., are used. Further, the optical 4-layer is formed by various methods such as vapor deposition and resin binding.

The illustrated example is a photoreceptor in which a vapor-deposited layer of Se-'l''e alloy is used for the light guide 11L layer.

The first step (FIG. 12(a)) is a primary charging step in which the surface of the photoreceptor 8 is uniformly charged to a predetermined polarity (negative) by a primary corona discharger C. E; is a power source. Conductive substrate of photoreceptor,
A power source is connected to ft and a voltage of opposite polarity (positive) to the primary charge is applied. The applied pressure m is set at l- so that the surface potential after the primary band's voltage is approximately zero.

The second step (FIG. 12(b)) k, 1 is an AC static elimination step at the same time as optical information irradiation. In the same process, at the same time as the optical information irradiation similar to the example shown in the sixth figure, a direct current positive voltage approximately equal to the voltage applied to the L distribution power source is superimposed on the two connected to the AC power source. The next corona discharger C: performs AC relief.At this time, it is also possible to use only a direct current corona discharge with the opposite polarity to the next one.The surface charge on the dark area of the photoreceptor (D) is only slightly removed. However, in the bright area (L), most of the charges are removed and only some charges remain. Therefore, the surface potential rises again from approximately 1 to near the applied voltage from the source.

The third step (FIG. 12(C)) is an entire surface exposure step.

In the previous process, the unbalanced positive charges at the dark interface of the photoreceptor are
In this step, it is released and released to the conductive substrate, so the surface potential of the dark area becomes low. On the other hand, since the bright area is approximately balanced in the second step, there is no large potential change.

The fourth step (FIG. 12(d)) is a developing step, in which a developer T' of the same polarity (negative) as the primary charging is used to
). The developer T' on the photoreceptor is 1!1. source g
Adsorption force is obtained by the applied m pressure of W, and the fear of scattering to the surroundings during the subsequent process is eliminated.

The fifth step (FIG. 12(e)) is a transfer step, in which the transfer material P
A transfer corona is applied from the back side by a transfer corona emitting device C/ to transfer the developed images on the photoreceptor.

The developer adsorption voltage applied to the photoreceptor conductive substrate b1 by the power source E: prevents early developer transfer that would cause disturbance of the transferred image, resulting in good transfer.

In the specific example process described above, the developer adsorption voltage may be applied to the photoreceptor substrate only after the development step and until the transfer step.

It is also effective to do the same thing after the transfer process and before the cleaning process.

Hereinafter, a specific example of a 4U apparatus that implements the above process will be described with reference to FIG.

In the device shown in the figure, members common to those in the device shown in the seventh figure are designated by the same numbers. The difference from the above-mentioned device is that the photosensitive drum 1' includes the above-mentioned conductive α substrate b1, photoconductive layer l)1,
17, a primary corona radiation device 31, and a latent image forming means;
32 optically open-backed secondary corona dischargers, 3
It is equipped with 3 full-surface exposure lamps. A bias power supply 21 applies an electric current having a polarity opposite to that of the voltage applied to the negative corona discharger to the photoreceptor.

Further, the charge polarity of the developer 9 is the same as the applied voltage polarity of the negative corona discharger.

The operation of the above-mentioned component device is as follows.

The surface of the photosensitive drum 1' is uniformly made into a negative polarity band by a secondary corona discharger 31 and receives optical information irradiation 5 based on an image scanning method, and at the same time, a corona discharge having a positive polarity component is generated by a secondary corona discharger. will be administered. Furthermore, the entire surface exposure lamp 33
Upon uniform exposure, a static latent image is formed on the surface of the photoreceptor. Next, the photosensitive drum passes through a developing position, and the latent image on the surface is reversely developed.

The developed images on the surface of the photoreceptor are moved to the transfer position without being scattered inside the machine by the attraction voltage of the bias mechanism 2I' mentioned above. During this process, the surface of the photoreceptor is uniformly charged by a pre-charger 10, and then the surface is developed by a transfer corona discharger 12.
is transferred to the transfer material. After the transfer, the photoreceptor is cleaned and prepared for reuse.

Examples will now be shown to further deepen the understanding of the present invention.

[Example 1] Using a photosensitive drum L in which a photosensitive layer of amorphous silicon containing water accumulation (1■) and oxygen (0) was formed to a thickness of about 30 μm, the apparatus having the configuration shown in the seventh figure was used. Using.

For source information irradiation, a 7801 m semiconductor laser was controlled using an image scan method. Furthermore, a commercially available NP2O0 developing device was used, and a one-component magnetic developer used in NP2O0 was used as the developer.

First, for comparison, image formation was performed without applying bias pressure to the M base of the photosensitive drum.

At this time, after negative polarity charging, the surface of the photoreceptor is
The potential is -400V in the dark area (VD) and -400V in the light area (vL).
It was 50V. This latent image is peak-to-peak (Pea
k to Peak) voltage 1200Y, frequency f =
1 KHz, a DC bias voltage of -250 V, development was carried out using a developing device, and transfer was performed /ζ. At this time, scattered toner was generated, and the transfer material was stained with the scattered toner. In addition, disturbances were found in the transferred image on the transfer material.

Next, a voltage of +500 V was applied to the M base of the photosensitive drum to form an image. At this time, the negative polarity band's position on the surface of the photoreceptor due to the irradiation of light information is + in the dark area (VD).
It was +450v at 100v1 light area (vL). This latent image was developed in the developing device by changing the DC bias voltage to +250V, and then transferred to a transfer material.At this time, no scattering of developer toner was found.Also, the transferred image was It was sharp and had no disturbances at all.

[Example 2] Using a photosensitive drum on which an 8e-Te alloy was deposited to a total thickness of about 70 μm on an M drum, and a transparent insulating layer with a thickness of about 33 μm was further provided,
An image forming experiment was conducted using the apparatus shown in FIG.

For optical information irradiation, a 780 nm rn semiconductor laser was used in the image scanning method as in the previous example. Also, as in the previous example, the developing device and developer were made from NP2O0.

First, for comparison, an image was formed without applying the voltage A (1, to the base of the photoreceptor) (Ias'). With polar charging, dark area (VD) is -450V, light area (vL)
) formed a latent image of Ov. Peak to peak (Pea
k to Peak ) voltage 1200V.

Frequency f = 1KHz, DC bias voltage -225
The latent image was developed using a developing device designated as V and transferred to a transfer material. At this time, the toner was scattered and the transfer material was stained with the scattered toner. K transfer image disturbance was also found.

Next, a voltage of 500 cm was applied to the AA base of the photosensitive drum to form both images. The surface of the photoreceptor is covered by the primary band ridges.
Tooov band 1~1, reverse polarity charging at the same time as light information irradiation, dark area (VD) -1-50V, light area (vL) +50
It forms a latent image of 0v and is 2. Developing was carried out with the DC bias voltage of the developing device set to +275 V, and then transfer was performed. At this time, no scattering of developer toner was found. Further, the transferred image was sharp without any disturbance.

As described above in detail using specific examples, the present invention enables good image formation without developer scattering. Moreover, it is an excellent product that can obtain a good transferred image without disturbance of the transferred image even when performing transfer of reverse development.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a laser printer based on the conventional method; FIG. 2 is an explanatory diagram of changes in photoreceptor surface potential in the apparatus shown in FIG. 3; FIG. 3 is an explanatory diagram of a forming copy example; The figure is an explanatory diagram of the development of the second illustrated potential latent image, Figure 5C.
, FIGS. 6(a) to 6(d) are diagrams explaining the principle of developer scattering,
An explanatory diagram of a specific example process based on the present invention, Fig. 7 11 An explanatory diagram of a body side device based on the present invention, Fig. 8 υ
1. 7 is an explanatory diagram of the electric field between the N & light body surface potential in the device shown in FIG. Explanatory diagrams of different specific examples of devices based on the invention.
Conductive substrate, 4... Primary band device, 5... Laser irradiation light, D... Developer, 7... Doctor blade, 8...
・・Mag applicant Canon Co., Ltd.

Claims (2)

[Claims] (1) In an electrophotographic method in which optical information is irradiated onto a photoreceptor to form a corresponding electrostatic latent image, the electrostatic latent image is reversely developed and transferred onto a transfer material, at least reversal development is performed. An electrophotographic method characterized by applying a developer adsorption voltage to a photoreceptor from completion to transfer. (2) In an electrophotographic device that forms an image on a photoconductor in response to irradiation of optical information, the photoconductor has a conductive substrate, a means for forming a latent image on the photoconductor in response to irradiation of optical information, and a photoconductor. An electrophotographic device comprising: a developing means for applying a developer having a predetermined charge polarity to an optical information irradiation area of a body; and a means for applying a voltage having a polarity opposite to the charge polarity of the developer to a conductive substrate of a photoreceptor. Device.