JPH1039554A - Method and device for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device constituted so that carrier is surely prevented from being attached to a non-image part. SOLUTION: In an image forming process, the surface of a photoreceptor is uniformly exposed by an optical write means exposing light corresponding to an image after it is uniformly electrostatically charged to Vh by an electrostatic charger. At this time, the surface of the photoreceptor becomes identical to bias potential Vb. That means, the full surface lateral lader latent image of 21p/mm is formed on a photoreceptor drum by the exposure corresponding to the image by the intensity of -400V. At this time, toner is not developed on the photoreceptor by such potential difference and the carrier is attracted to the photoreceptor by cleaning potential (difference between the surface potential Vh of the photoreceptor and the bias potential Vb of a developer carrier). In this case, a transfer process is not executed and a recording paper is not also carried. Besides, the carrier attached to the photoreceptor by the rotational movement of the photoreceptor is eliminated from the photoreceptor by a cleaner. Then, the image forming device is actuated by three minutes in this mode and a regular image is formed after three munutes elapses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying apparatus or an image forming apparatus such as a printer using a two-component developer composed of a toner and a carrier.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, the surface of a photoreceptor, which is an electrostatic latent image carrier, is uniformly charged by a charging device, and the surface of the photoreceptor is charged by an exposure device in accordance with image information. Form a latent image. Then, the electrostatic latent image is developed with toner of a developing device to be visualized. The developing device carries a two-component developer composed of a toner and a magnetic carrier on a developer carrier in which a cylindrical magnet having a plurality of magnetic poles is fixedly arranged in a developer carrier inside a cylindrical non-magnetic sleeve, The two-component developer on the developer carrier is conveyed by the rotation of the non-magnetic sleeve, and the electrostatic latent image is brought into contact with the two-component developer to be visualized with toner.

In the above-described two-component developing method, first, a toner and a carrier are brought into contact with each other in a developing device to charge them with opposite polarities. In the reversal development, the photoconductor is charged to the same polarity as the toner, the image area is exposed to light by an exposure device to eliminate the charge, and the developing carrier is set at an intermediate potential between the image area potential and the non-image area potential. Adhered to the image area with force and developed. In normal development, the toner is charged by charging the photoreceptor to the opposite polarity to the toner, exposing the non-image portion with an exposure device to remove the charge, and setting the developing carrier at a potential between the image portion potential and the non-image portion potential. Adhered to the image area and developed. In either case, the carrier exerts a suction force on the non-image area by electrostatic force, but prevents the carrier from adhering to the non-image area by a magnetic attraction force with the developing carrier.

[0004]

However, each carrier has an electrostatic force and a magnetic force which act due to a difference in charge amount and saturation magnetization due to a difference in particle size and shape, or a difference in charge amount and saturation magnetization itself. Are different. For this reason, a carrier that strongly acts on the electrostatic force or a carrier that acts weakly on the magnetic force adheres to the non-image portion. Particularly, in a carrier manufactured by dispersing magnetic powder in a resin and pulverizing and classifying into fine particles, the dispersion of the above-mentioned particle size and shape, or the dispersion of the charge amount and the saturation magnetization itself are large, and the non-image part Carrier adhesion was easy to occur.

[0005] When the carrier adhered to the non-image portion is transferred together with the toner onto the paper (recording body), the carrier may be fused to the surface of the fixing roll used in a fixing device that fuses the toner image by heat, and may damage the surface of the fixing roll. In such a carrier in which magnetic powder is dispersed in a resin, the carrier is fixed on a recording medium as it is, resulting in an image quality defect. In addition, since the carrier is larger than the toner, the toner image adjacent to the portion where the carrier has adhered is not transferred to the recording medium, causing an inconvenience of image omission. As a method for preventing the carrier from adhering to the non-image portion, a method of reducing the potential difference between the non-image portion and the developing carrier can be considered. Oops.

Further, as an image, a fringe electric field is formed at the edge of the solid as shown in FIG. 9A, and the electric field perpendicular to the surface of the photoreceptor is as shown in FIG. 9B.
The carrier easily adhered to the non-image area. In particular, as shown in FIG. 10, in a ladder in which high-frequency lines are continuous, the fringe electric field is further increased, and thus the ladder is most likely to adhere. That is, since the electric field changes at a high frequency in the ladder, carriers having high tracking ability to the electric field change adhere. The same phenomenon occurred in characters with a large number of strokes.

Normally, the carrier adhesion to the non-image area is prevented by the magnetic pole parameter of the magnet of the developing carrier, the parameter of the carrier, and the like. However, since the carrier that easily adheres is included as described above, ,
It has been difficult to eliminate carrier adhesion to non-image areas. A method for solving this problem has been proposed in Japanese Patent Application Laid-Open No. Hei 6-27821. This means that before the actual use mode, the potential difference between the non-image area and the development carrier is increased, and the developing device is operated to forcibly discharge the carrier that tends to adhere to the non-image area onto the photoreceptor in advance. Have done
In the actual use mode, the carrier is not attached to the non-image portion.

However, in the disclosed method, since the electric field is a uniform electric field, if the potential difference is set so as to discharge the carrier that easily adheres to the ladder or the character portion, the carrier adheres without following the change in the potential difference of the ladder. Even carriers that do not have to be discharged will be discharged. On the other hand, if the potential difference is too small, it is impossible to prevent the carrier from adhering to a ladder, a character portion, or the like. SUMMARY An advantage of some aspects of the invention is to provide an image forming apparatus capable of reliably preventing carrier from adhering to a non-image area.

[0009]

In order to solve the above-mentioned problems, a uniformly charged electrostatic latent image carrier according to the first invention is irradiated with an exposure corresponding to an image, and a static image corresponding to the image is irradiated. An electrostatic latent image forming step of forming an electrostatic latent image by a difference in electric potential,
A developing step of developing the electrostatic latent image with toner based on a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier when the electrostatic latent image faces the developer carrier; An image forming method using a two-component developer having a cleaning step of cleaning toner on a latent image carrier has a potential difference in a range where the electrostatic latent image carrier does not develop toner with respect to the potential of the developer carrier. An electrostatic latent image forming step for discharging a carrier that forms an electrostatic latent image based on an image forming a fringe electric field with a potential having a potential difference between the potential of the developer carrier and a range in which toner is developed An electrostatic latent image forming step for forming an electrostatic latent image is formed by a potential difference. The electrostatic latent image formed in the carrier discharging electrostatic latent image forming step faces the developer carrier. The two-component developer carrier The basically equipped.

The electrostatic latent image forming step according to the image forming method of the second invention includes a first latent image forming step by exposure corresponding to the first image and a second latent image forming step by exposure corresponding to the second image. A latent image forming step, wherein the second latent image step is a negative exposure when the first latent image forming step is a positive exposure, and a second latent image step when the first latent image forming step is a negative exposure Performs positive exposure, and develops the latent image formed in the first latent image process by developing the latent image formed in the second latent image forming process in the first developing process of normal developing or reversal developing. A second developing step of developing with a two-component developer comprising a toner and a magnetic carrier, wherein in the first latent image forming step, an electrostatic latent image for forming a fringe electric field is formed; Is not executed, and in the second latent image forming step, the electrostatic latent image carrier is Against a potential having a potential difference in the range that does not develop the toner, basically comprises a structure for adsorbing the carrier of the second running development process with a two-component developer.

According to the third aspect of the present invention, a uniformly charged electrostatic latent image carrier is exposed to light corresponding to an image to form an electrostatic latent image based on a difference in electrostatic potential corresponding to the image. A latent image forming means, a developing means having a developer carrier for carrying a two-component developer comprising a toner and a magnetic carrier, and a cleaning means for cleaning toner on the electrostatic latent image carrier; When the electrostatic latent image on the image carrier faces the developer carrier, the electrostatic latent image is developed by toner due to a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier. An image forming apparatus using a two-component developer has an electrostatic latent image carrier at a potential having a potential difference within a range that does not develop toner with respect to the potential of the developer carrier, and an image formed by a fringe electric field. An electrostatic latent image forming means for discharging a carrier for forming a latent image; and An electrostatic latent image forming means for forming an electrostatic latent image with a potential difference having a potential difference within a range in which the toner is developed with respect to the potential of the developer carrier, and an electrostatic latent image for discharging a carrier; The electrostatic latent image formed by the forming means has a configuration in which a carrier of a two-component developer is adsorbed when facing the developer carrier.

An image forming apparatus according to a fourth aspect of the present invention irradiates a uniformly charged electrostatic latent image carrier with exposure corresponding to an image to form an electrostatic latent image based on a difference in electrostatic potential. Electrostatic latent image forming means, developing means for developing the electrostatic latent image with toner by a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier, and Cleaning means for cleaning the toner, the electrostatic latent image forming means comprising: a first latent image forming means by exposure corresponding to the first image; and a second latent image by exposure corresponding to the second image. A second latent image forming unit that has a negative exposure when the exposure corresponding to the first image is a positive exposure, and a second latent image when the exposure that corresponds to the first image is a negative exposure The forming means executes a positive exposure, and the developing means normalizes the latent image formed by the first latent image forming means. Alternatively inverting a first developing means for developing a second of developing the formed latent image with two-component developer comprising a toner and a magnetic carrier in a second latent image forming means
The first latent image forming means forms an electrostatic latent image for forming a fringe electric field, the first developing means is not executed, and the second latent image forming means forms a static latent image. Basically, the configuration is such that the electrostatic latent image carrier is set to a potential having a potential difference within a range where the toner is not developed with respect to the potential of the developer carrier, and the second developing unit is executed to adsorb the carrier of the two-component developer. Have. Also, the carrier adsorbed on the electrostatic latent image carrier is provided with a cleaning step or a cleaning means for cleaning the carrier.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment This embodiment relates to a monochrome image forming apparatus. FIG.
FIG. 1 is a schematic diagram illustrating an example of a single-color image forming apparatus. In this embodiment, a photosensitive member is used as the latent image carrier. The photoconductor drum 1 has a surface layer made of a negatively charged organic photoconductor on the surface. After the photosensitive drum 1 is uniformly charged by the charger 2, the photosensitive drum 1 is irradiated by the light writing means 3 for exposing light corresponding to an image, and an electrostatic latent image is formed by a difference in electrostatic potential. The surface potential when an electrostatic latent image is formed is, for example, −100 V in the image portion Vl and − in the background portion Vh.
It can be 700V. The electrostatic latent image formed on the photoconductor 1 is reversely developed by the developing device 4, and a toner image is formed on the photoconductor 1. The toner image is transferred onto the recording paper P by the transfer charger 5, and the recording paper P is separated from the photoreceptor 1 by the separation charger 6 after the transfer.
The image is fixed by a fixing unit (not shown). The residual toner on the photoconductor 1 is removed by a cleaner 7 and the photoconductor 1 is removed.
The above residual charges are removed by the discharging lamp 8.

FIGS. 2 and 3 show the developing device 4. The developer carrier 40 of the developing device 4 is provided to face the photoconductor 1.
Then, the developer adhered to the surface is transported by the rotation. The gap L _{1 in the} region closest to the photoconductor ₁ is 40
It is set to be about 0 to 600 μm. The developer carrier 40 includes a magnet roll 401 and a developing sleeve 403.
Consisting of A plurality of magnetic poles are arranged inside the magnet roll 401 along the peripheral surface, and are fixed and supported so as not to rotate. The developing sleeve 403 is formed by the magnet roll 401.
A magnetic field is formed along the peripheral surface, and a two-component developer composed of a magnetic carrier and a non-magnetic toner can be adsorbed on the surface of the developer carrier 40 according to the magnetic field.

The developing device 4 is provided with a developer conveying / stirring means 41, and the developer conveyed to the developer supply area by the stirring means 41.
The component developer is supplied to the developer carrier 40 by the developer supply unit 43 and is magnetically attracted. Further, the amount of the developer adsorbed on the developer carrier 40 is regulated by the developer regulating member 45, and is conveyed to the developing area facing the photosensitive drum 1. The developer in which the toner has been consumed in the developing area is separated from the developer carrier 40, and is again conveyed to the developer conveying and stirring means 41 by the developer supply means 43. The toner in the developing device 4 is supplied from a supply port 47 by toner supply means (not shown), and circulates in the direction shown by the arrow while stirring the toner and the developer by the stirring means 41 to make the toner concentration uniform. I have.

A description will now be given of the potential difference between the developing carrier 40 and the surface of the photosensitive member 1 configured as described above (see FIG. 4). A bias voltage Vb is applied to the developer carrier 40 by a high-voltage power supply (not shown). This bias voltage Vb is, for example, -500V. -1 at the image portion Vl on the surface of the photoconductor 1
Assuming that the potential is 00 V and the background portion Vh is −700 V, the toner is developed on the photoconductor 1 with a potential difference (developing potential) of 400 V between the potential of the developer carrier 40 and the image portion potential Vl of the photoconductor 1,
Potential difference (cleaning potential) 30 from non-image portion potential Vh
At 0 V, the toner is prevented from adhering to the photoconductor. Here, an AC component may be superimposed on the bias voltage as needed.

In this state, a development test having a 2 lp / mm ladder image was attempted. As the developer, magenta toner having an average particle diameter of about 7 μm and an average particle diameter of about 50 μm,
Ferrite particles having a saturation magnetization of 60 emu / g were coated with a resin and the resistance was controlled. The toner concentration in the developer was about 8.0% by weight. The linear velocity of the photoconductor 1 is 160 mm / s, and the linear velocity of the developer carrier 41 is 320
mm / s, and development was performed by rotating so as to move in the same direction in the opposed development areas. As a result, the carrier adhesion to the background portion of the image on the photoreceptor 1 is 5 to 10 in a 40 mm × 40 mm area, and 20 to 30 in a 2 lp / mm ladder image. In the image, image omission occurred due to carrier adhesion.

Therefore, in this embodiment, the following mode (carrier discharging mode) was executed (see FIG. 5). In the image forming process, the surface of the photoreceptor 1 is uniformly charged to Vh by the charger 2, and then uniformly exposed by the light writing unit 3 for exposing light corresponding to the image. At this time, it becomes the same as the bias potential Vb, that is, −40.
A 2 lp / mm horizontal ladder latent image is formed on the photosensitive drum 1 by exposure corresponding to the image at an intensity of 0 V. Next, the developing device 4 is operated. At this time, the toner is not developed on the photoconductor 1 by the potential difference, and the carrier is attracted to the photoconductor at the cleaning potential (the difference between the photoconductor surface potential Vh and the development carrier Vb). In this case, the image forming apparatus does not perform the transfer process and does not convey the recording paper P. Then, the carrier adhered to the photoconductor 1 due to the rotational movement of the photoconductor 1 is removed from the photoconductor 1 by the cleaner 7. This mode was operated for 3 minutes, and a normal image was formed after the operation.

The result of the image formation is that the carrier adheres to the background portion of the image on the photoreceptor 1 within an area of 40 mm × 40 mm.
Or less, and 5 to 10 carriers adhered in the image of the 2 lp / mm ladder. As a result, image omission due to carrier adhesion in the fixed image of the ladder was reduced as compared with the image formation result in the conventional image formation. A similar image forming experiment was performed with a black toner having an average particle size of about 9 μm, but the same effect was obtained. As described above, since the image forming apparatus according to this embodiment includes the carrier discharging step for efficiently discharging the carrier that easily adheres before image formation, the fringe electric field of ladders, characters, and the like is strong. Also in the image formation, a good image can be formed without image quality defects and image omission due to carrier adhesion.

Second Embodiment This embodiment relates to a color image forming apparatus. FIG.
FIG. 1 is a schematic diagram illustrating an embodiment of a two-color image forming apparatus.
The illustrated two-color image forming apparatus includes a negatively charged photoreceptor 10 rotating in the direction of arrow a, a charger (in the embodiment, a scorotron) 20 for charging the photoreceptor 10, and a first laser including a semiconductor laser.
The optical writing unit 30A, the second optical writing unit 30B, the first developing unit 400A, the second developing unit 400B having a different charging polarity from the first developing unit 400A and having a different color, and two colors formed on the photoconductor 10 A pre-transfer charger 90 for charging the toner image to make the polarity uniform, a transfer charger 50 for collectively transferring the two color toner images on the photoconductor 10 onto the recording paper P, and a transfer paper from the photoconductor 10 after the transfer. Peeling charger 6 for peeling P
0, cleaner 7 for removing residual toner on photoconductor 10
0, static elimination lamp 80 for removing residual charges on photoconductor 10
It has.

Next, an image forming process of the two-color image forming apparatus according to this embodiment will be described with reference to FIG. Charging Step a The surface of the photoconductor is uniformly charged (charge potential Vh). First exposure step (b) The image portion is exposed positively to form a first latent image having an image portion potential of V11. First Developing Step c The image portion of the first latent image is subjected to reverse development (developing bias potential Vb1) with toner having the same polarity as the charged polarity of the photoconductor 10. Second exposure step d The second non-image portion (including the toner image portion of the first color) is negatively exposed to form a second latent image (non-image portion potential V12). Second developing step e At the developing bias potential Vb2, the image portion of the second latent image is regularly developed with a toner having a polarity opposite to the charging polarity of the photoconductor 10 and a color different from that of the first color toner. Through these steps, a two-color toner image is formed on the photoconductor.

In the two-color image forming method, since the two-color toners have opposite polarities and the normal development and the reversal development are used, the generation of the mixed color in which the second color toner adheres to the first color toner image. It is hard to remove. In addition, there is an advantage that the problem that the first color toner is mixed into the second color developer and the second color becomes turbid does not easily occur, and that the photoreceptor does not need to be recharged before the second color development.

With this image forming apparatus,
A development test of an original having a 2 lp / mm ladder image was attempted. The first developing device 400A has a negatively charged blue toner having an average particle diameter of about 11 μm and an average particle diameter of about 85 μm as a developer.
Ferrite particles having a saturation magnetization of 60 emu / g were coated with a resin and the resistance was controlled. The toner concentration in the developer was about 4.0% by weight. The linear velocity on the developer carrier was 480 mm / s. Second developing device 400B
In order to prevent the toner image of the first color from being disturbed when the developer comes into contact with the photoconductor, the linear speed of the photoconductor is set to 160 mm / s and the linear speed of the developer carrier is set to 208 mm / s. The speed difference with the body 10 is reduced. Further, a resin carrier is used. The resin carrier is a dispersion of magnetic powder obtained by mixing and mixing 65 parts of magnetite with 35 parts of a polymethyl methacrylate copolymer, melt-kneading and then finely pulverizing the resin carrier. Since the specific gravity is smaller than the ferrite-based carrier, the rubbing force on the first color toner image is small. The toner used was a positively charged red toner having an average particle size of about 11 μm.

The potential conditions are as follows: charging potential Vh is -730 V;
The first image portion potential Vl1 is -120V, the first developing bias potential Vb1 is DC -450V, while the second non-image portion potential Vl2 is -200V, and the second developing bias potential Vb2.
Was set to DC-350V. In the first development, a negatively-charged blue toner having an average particle diameter of about 11 μm and a ferrite particle having an average particle diameter of about 85 μm and having a saturation magnetization of 60 emu / g coated with resin to control the resistance value were used as the developer. The toner concentration in the developer was about 4.0% by weight.
The linear velocity on the developer carrier was 480 mm / s.

As a result of the image formation, a slight amount of the second color resin carrier fixed on the background portion of the paper was observed. 2lp
In the ladder of / mm, there is an image omission in the line that is the image part,
Significant carrier adhesion occurred around the line. Therefore, in this embodiment, the following mode (mode for discharging carrier) is used.
(See FIG. 8). Formation of Latent Image of First Color In a state where the first developing device 400A is separated from the photoconductor 10, a 2 lp / mm ladder latent image is formed on the entire surface of the photoconductor 10 with the intensity of V11 by the first light writing means 30A. . Second latent image formation and carrier discharge Further, Vb2
The entire surface of the photoreceptor is exposed at an intensity of
Act. At this time, the carrier of the second developing device 400B is attracted to the photoconductor 10 by the potential difference between the potential V11 of the photoconductor 10 and the potential Vb2. The image forming apparatus does not operate the transfer process and does not convey the recording paper P. The carrier adhered with the rotation of the photoconductor 1 is removed from the photoconductor 10 by the cleaner 70. When an image was formed after operating for 3 minutes in this mode, no fixed second-color resin carrier was found on the background of the paper, and 2 lp / m
In the ladder of m, no line was lost in the image area, and almost no carrier adhesion was observed around the line.

In a normal color image forming process in which reversal development, recharging and reversal development are repeated, the same process as that for the first color is repeated. Although the carrier is not discharged in the developing step, as described above, the two-color image forming by the image forming apparatus of this embodiment has a step of efficiently discharging the carrier which easily adheres before forming the image. Therefore, even in image formation in which the fringe electric field of a ladder, a character, or the like becomes strong, a good image can be formed without image quality defects and image omission due to carrier adhesion. Although the embodiment shows the image forming apparatus of the contact developing system, the same effect can be obtained even if the image forming apparatus is of the non-contact developing type if it is a two-component developing.

[0027]

As described above, according to the present invention, in forming an image using a two-component developer comprising a toner and a magnetic carrier, the toner is applied to the electrostatic latent image carrier with respect to the potential of the developer carrier. An electrostatic latent image pattern that forms a fringe electric field with a potential in a range not to be developed is formed, and only the carrier is attracted to the electrostatic latent image carrier by operating the developing device, and then removed by the cleaning unit. By operating the process for a predetermined time, the carrier that easily adheres to the non-image area from the developing device can be efficiently and effectively discharged.
As a result, the amount of carriers adhering to the non-image area during image creation is reduced, and damage to the surface of the fixing roll due to carrier adhesion and occurrence of image quality defects fixed by the resin carrier are prevented. Further, image omission due to carrier adhesion can be prevented, and a good image can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view of a developing device according to the present invention.

FIG. 3 is an explanatory diagram of a state of a developer in a developing device.

FIG. 4 is an explanatory diagram illustrating an image forming process of the image forming apparatus.

FIG. 5 is an explanatory diagram of a mode for discharging a carrier that easily adheres to a non-image portion.

FIG. 6 is a schematic diagram of a two-color image forming apparatus according to the present invention.

FIG. 7 is an explanatory diagram illustrating an image forming process of the two-color image forming apparatus.

FIG. 8 is an explanatory diagram of a mode for discharging a carrier that easily adheres to a non-image portion.

FIG. 9 is an explanatory diagram of a fringe potential.

FIG. 10 is an explanatory diagram of a fringe potential.

[Explanation of symbols]

1 photoreceptor, 2 charger, 3 light writing means,
4 developing device, 5 transfer charger, 6 peeling charger,
Reference Signs List 7 cleaner, 8 static elimination lamp, 40 developer carrier, 41 developer stirring means, 43 developer supply means, 401 magnet roll, 403 development roll, P
Recording paper.

Claims (10)

[Claims] An electrostatic latent image forming device for irradiating a uniformly charged electrostatic latent image carrier with an exposure corresponding to an image to form an electrostatic latent image based on a difference in electrostatic potential corresponding to the image. A developing step of, when the electrostatic latent image faces the developer carrier, developing the electrostatic latent image with toner by a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier. In an image forming method using a two-component developer having a cleaning step of cleaning toner on an electrostatic latent image carrier, the electrostatic latent image forming step includes a step in which the potential of the electrostatic latent image carrier is changed to a potential of the developer carrier. A latent image forming step for forming an electrostatic latent image by an image forming a fringe electric field at a potential having a potential difference in a range where the toner is not developed, An electrostatic latent image with a potential difference having a potential difference in the developing range Has a latent image forming step for forming an image for forming an electrostatic latent image formed by the latent image forming step for carrier discharging when facing the developer carrying member,
An image forming method comprising adsorbing a carrier of a two-component developer. 2. The image forming method according to claim 1, wherein the latent image forming step for discharging the carrier is operated for a predetermined time before executing the latent image forming step for forming an image. 3. An electrostatic latent image forming apparatus that sequentially irradiates a uniformly charged electrostatic latent image carrier with exposure corresponding to a plurality of images to sequentially form a plurality of electrostatic latent images based on a difference in electrostatic potential. An image forming step; a developing step of sequentially developing the electrostatic latent image with toner based on a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier; The electrostatic latent image forming step includes a first latent image forming step by exposure corresponding to the first image and a second latent image forming step by exposure corresponding to the second image. When the first latent image forming step is a positive exposure, the second latent image step performs a negative exposure, and when the first latent image forming step is a negative exposure, the second latent image step performs a positive exposure. The developing step is a first developing step in which the latent image formed in the first latent image step is subjected to regular development or reverse development. And a second developing step of developing the latent image formed in the second latent image forming step with a two-component developer comprising a toner and a magnetic carrier. In the first latent image forming step, a fringe electric field is formed. A range in which the first latent image forming step is not performed and the first latent image forming step is not performed, and in the second latent image forming step, the electrostatic latent image carrier is not developed with toner with respect to the potential of the developer carrier. And an image forming method configured to cause the carrier of the two-component developer to be adsorbed by performing the second developing step by using a potential having the potential difference described above. 4. The image forming apparatus according to claim 3, wherein the second developing step performs reversal development when the first development step is regular development, and performs regular development when the first development step is reversal development. Method. 5. The image forming method according to claim 1, wherein the carrier adsorbed on the electrostatic latent image carrier is cleaned by a cleaning step. 6. An electrostatic latent image forming means for irradiating a uniformly charged electrostatic latent image carrier with exposure corresponding to an image to form an electrostatic latent image based on a difference in electrostatic potential corresponding to the image. Developing means having a developer carrier for carrying a two-component developer composed of toner and magnetic carrier; and cleaning means for cleaning toner on the electrostatic latent image carrier, wherein the electrostatic latent image is When opposed to the carrier, an image forming apparatus using a two-component developer in which an electrostatic latent image is developed with toner by a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier, The electrostatic latent image forming means forms an electrostatic latent image by an image forming a fringe electric field at a potential having a potential difference in a range where the electrostatic latent image carrier does not develop toner with respect to the potential of the developer carrier. Electrostatic latent image forming means for discharging carrier, and developing An electrostatic latent image forming unit for forming an electrostatic latent image with a potential difference having a potential difference in a range in which the toner is developed with respect to the potential of the carrier, and an electrostatic latent image forming unit for discharging a carrier An image forming apparatus configured to adsorb a carrier of a two-component developer when an electrostatic latent image formed by the above-mentioned method is opposed to a developer carrier. 7. The image forming apparatus according to claim 6, wherein the electrostatic latent image forming means for discharging the carrier is operated for a predetermined time before the electrostatic latent image forming means for forming an image is operated. 8. A plurality of electrostatic latent image forming means for irradiating a uniformly charged electrostatic latent image carrier with exposure corresponding to an image to form an electrostatic latent image based on a difference in electrostatic potential. Developing means for developing the electrostatic latent image with toner based on a potential difference between the developer carrier and the electrostatic latent image on the electrostatic latent image carrier, and cleaning means for cleaning the toner on the electrostatic latent image carrier. The electrostatic latent image forming means has a first latent image forming means by exposure corresponding to a first image, and a second latent image forming means by exposure corresponding to a second image. If the exposure corresponding to the image is positive exposure, the second latent image forming means is negative exposure,
If the exposure corresponding to the first image is a negative exposure, the second latent image forming means executes a positive exposure, and the developing means develops the latent image formed by the first latent image forming means into regular development or reverse development. And a second developing unit for developing the latent image formed by the second latent image forming unit with a two-component developer composed of toner and a magnetic carrier. In the means, an electrostatic latent image for forming a fringe electric field is formed, and the first developing means is not executed. In the second latent image forming means, the electrostatic latent image carrier is moved to the potential of the developer carrier. On the other hand, an image forming apparatus having a potential having a potential difference within a range in which toner is not developed and executing a second developing means to adsorb a carrier of a two-component developer. 9. The image forming apparatus according to claim 8, wherein the second developing means performs reverse development when the first developing means is normal development, and performs normal development when the first developing means is reverse development. apparatus. 10. The image forming apparatus according to claim 6, wherein the carrier attracted to the electrostatic latent image carrier is cleaned by a cleaning unit.