JPH07219388A - Image forming method and image forming device - Google Patents

Abstract

PURPOSE:To make fine particles of an image forming medium float in the air by the pressure of light and to maintain the particles as floating, and to move the fine particles of the image forming medium in the direction of the recording medium for printing. CONSTITUTION:A light barrier 2 is formed and fine particles 3 of an image forming medium are maintained in this light barrier 2. Then, the particles 3 of the image forming medium are irradiated with light from a driving means 6 for fine particles disposed facing the recording medium 7 with the light barrier 2 interposed. The fine particles 3 irradiated with light are pressed through the light barrier 2 to deposit on the recording medium 7. Thereby, an image is formed on the recording medium 7. The excess particles 3 not used for printing in the fine particles 3 of the image forming medium supplied from the fine particle supply device 4 on the optical barrier 2 are recovered by a particle recovering device 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer or a copying machine.

[0002]

2. Description of the Related Art Conventional image forming apparatuses such as printers and copying machines generally use an electrophotographic system. Figure 2
FIG. 1 is a configuration diagram of a conventional electrophotographic image forming apparatus. In the figure, 8 is a photoconductor, 9 is a charger, 10 is an exposure device, 11 is a developing device, 12 is recording paper, 13 is recording paper conveying means, 14 is a transfer device, 15 is a fixing device, 16 is an eraser lamp, 17 is a cleaner.

In this conventional image forming apparatus, after the surface of the photoconductor 8 is charged by the charger 9, the photoconductor 8 is irradiated with light modulated based on image information to expose the photoconductor 8 to light. An electrostatic latent image is formed on the surface. Developing device 11
Contains charged toner, and when an appropriate developing bias voltage is applied, the electrostatic latent image is developed with the toner to form a toner image. When the photoconductor 8 rotates, the toner image is transferred onto the recording paper 12 by electrostatic force at a position facing the transfer device 14. The recording paper 12 is the conveying means 1
The toner image is conveyed to the fixing device 15 by 3 and the toner image is fused on the recording paper 12 by heat in the fixing device 15.

In this way, an image is formed on the recording paper 12. After that, the recording paper 12 is sent out onto the tray (not shown) by the conveying means 13. On the other hand, recording paper 12
After the toner image is transferred onto the surface, the surface of the photoconductor 8 is discharged by turning on the eraser lamp 16. Also,
The toner remaining on the photoconductor 8 is removed by the cleaner. By repeating the above process, continuous printing is performed.

The above-mentioned conventional image forming apparatus is composed of many parts and has a complicated structure. Therefore, there is a problem that the device becomes large. Therefore, in order to solve this problem, the present applicant has previously proposed an image forming apparatus described in Japanese Patent Laid-Open No. 4-10955. The image forming apparatus according to this proposal circulates an image forming medium such as toner while floating in a circulation path, and irradiates a laser beam to the toner coming to the circulation path opening provided at the recording paper facing position to The toner is made to adhere to the recording paper by the energy (irradiation pressure). With such a configuration, the photoconductor, the charger, the transfer device, the eraser lamp, and the cleaner are not required, and the device is simplified and the cost is reduced.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the prior art described in Japanese Patent Publication No. 5, since a circulation path for circulating the image forming medium is provided, the image forming medium adheres to and accumulates on the inner wall surface of the path, and the circulation path must be regularly cleaned. There is a problem of not becoming. Further, there is also a problem that the image forming recording medium to which the light irradiation pressure is not applied adheres to the recording paper through the opening and stains the image.

An object of the present invention is to provide an image forming method and an apparatus for holding an image forming medium without using a circulation path and moving the image forming medium onto a recorded matter by irradiation pressure of light.

[0008]

The above object is to provide a light barrier forming means for forming light barriers at spaced positions on a recording medium in an image forming apparatus for adhering fine particles of the image forming medium to the recording medium to form an image. A fine particle supplying device for supplying a group of fine particles of an image forming medium to the light barrier to float / hold them in a layer form, and a fine particle for pushing an image forming fine particle at a corresponding position through a light barrier to a recording medium side according to a formed image and adhering to the recording medium. This is achieved by providing a driving means and a collecting means for collecting the image forming medium fine particles remaining on the light barrier.

[0009]

Operation: A light barrier is formed at spaced positions on a recording medium, and a group of fine particles of image forming medium are suspended and held in the light barrier in a layered manner, and fine particles of image forming medium on the light barrier at corresponding positions are formed according to an image to be formed. Is extruded toward the recording medium through the light barrier to adhere to the recording medium, and a desired image is formed on the recording medium. This eliminates the need for a photosensitive drum, a charging unit, a discharging unit, and the like.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the principle of the present invention will be described. When a light ray is incident on the surface of fine particles, reflection and refraction occur, and the traveling direction of the light ray changes. FIG. 3 is an explanatory diagram of the principle that pressure acts on fine particles due to a change in momentum of light. Reference numeral 18 is fine particles, 19 is incident light, and 20 is reflected light. When the light ray 19 is reflected on the surface of the fine particles 18 and the traveling direction of the light changes,
The momentum of the light beam changes. Radiant pressure (irradiation pressure) acts on the fine particles 18 depending on the momentum change ΔP. The size F becomes maximum when all the incident light is reflected in the direction opposite to the incident direction. If the power of the ray is P and the speed of light is c,

[0011]

## EQU1 ## F = 2P / c. In practice, the reflectance and absorptance of light rays are fine particles 18
Since the refractive index changes depending on the refractive index and the incident angle of the light beam, the light pressure acting on the fine particles 18 decreases. However, the magnitude of the light pressure is such that the movement of the fine particles 18 can be controlled and the fine particles 18 can be suspended in the space.
As an example demonstrating this phenomenon, there is a report described in Proceedings 29a-Za-3 of the 40th Joint Lecture of the Japan Society of Applied Physics. In this report, a light beam is formed by a laser beam that is horizontally scanned, and fine particles can be held on the light barrier. By applying this phenomenon, the image forming medium is held on the optical scanning plane, the optical pressure is applied to an arbitrary image forming medium by another light source, and the image forming medium subjected to the optical pressure is applied on the optical scanning plane. An image can be formed on the recording medium by extruding from.

The magnitude of the light pressure required to suspend the image forming medium in the space will be examined with reference to FIG. FIG. 4 shows a state where the image forming medium is irradiated with a light beam having a Gaussian light intensity. An argon laser with an output of 5 W is continuously scanned horizontally (perpendicular to the paper surface of FIG. 4) by a polygon mirror to form a planar light film (light barrier). The power of light is effectively used by placing a mirror in a position directly facing the laser light source. Parallel light with a beam spot of 40 μm is used as a laser, spherical toner with a diameter of 10 μm (dielectric constant 3, specific gravity 1.1) is used as an image forming medium, and a mirror having a reflectance of 99.9% is used.

To form an image on a recording medium of A4 size, it is necessary to suspend toner in a region of length 210 mm × width 1 mm. Since 2.5 million toners exist in this area, the light power emitted per toner is 2.0 × 1.
0 ⁶ W. Calculating the upward component of the light pressure acting on one toner by changing the center position x of the toner, x becomes
In the range of −2 to 16 μm, the light pressure becomes larger than the gravity of 5.1 × 10 ¹² N acting on the toner. When x = 5 μm, the maximum light pressure is 9.8 × 10 ¹² N. Since the upward component of the light pressure becomes larger than the gravity, the toner can be suspended on the light barrier. The light pressure acting on the fine particles can be increased by increasing the light amount of the light source and providing an optical system that effectively uses the reflected light and the scattered light. The light pressure can also be increased by increasing the reflectance on the surface of the fine particles.

To form a printed image, a recording light source is installed above a horizontally formed light barrier, light is irradiated to a recording position, and toner is ejected from the light barrier by light pressure to be recorded. This is done by moving it onto an object. If the light source is provided with a light amount control system that weakens the scanning laser light for holding the toner only at the light irradiation position at the moment when the recording light is irradiated, an image can be formed more effectively.

FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a light barrier forming device, and the light barrier forming device 1 scans a laser beam horizontally (a direction vertical to the paper surface of FIG. 1) to form a light barrier 2. A particle group 3 such as toner is supplied from the particle supply device 4 onto the light barrier 2, and is collected by the particle recovery device 5. The fine particle driving device 6 irradiates the toner on the light barrier 2 with light and attaches the light to the image forming object.

When the light barrier 2 is irradiated in the b direction, fine particles such as toner and ink, which are image forming media, are held on the light barrier 2 by the light pressure and move in the b direction. The light barrier 2 is formed mainly by scanning laser light. The fine particle supply device 4 is disposed above the light barrier forming device 1, and the fine particle group 3 is individually separated from the fine particle supply device 1 by a vibrating means such as an ultrasonic vibrator or an oscillating electric field, and the light barrier is formed in the direction a. 2 on top. Light is applied to the particles that fall by gravity, and the light pressure causes the light barrier 2
Held on. The size of the fine particles is mainly several μm to several tens of μm, and one or two fine particle layers are held on the light barrier 2. The position of the particle supply device 4 does not have to be directly above the light barrier forming device 1, and as a method of supplying the particle group 3, the particle supply device 4 is supplied by using an air flow or the like from a direction orthogonal to the traveling direction (b direction) of light. You may.

The supplied fine particles float on the light barrier 2 due to the light pressure. The suspended fine particles are made to flow in the light traveling direction (direction b), and the fine particles remaining without being used for printing are collected by the fine particle collecting device 5.

As described above, in this embodiment, the light barrier forming device 1, the fine particle supplying device 4, and the fine particle collecting device 5 hold the thin layer of fine particles in the space, and an image is formed using this. Parts such as a photoconductor drum, a charging device, and a static eliminator are unnecessary, and a space-saving image forming apparatus can be obtained.

In the image printing method, the fine particles floating on the light barrier 2 are made to exert a force in the c direction by the fine particle driving device 6 so that the fine particles are adhered to the recording paper or film which is the image forming object 7. This is performed by fixing the image forming object 7 with a fixing device (not shown).

The individual parts will be described below. The light barrier forming device 1 is configured so that light is generated substantially horizontally in a planar shape. Although various light sources can be used for this light barrier generation device 1, laser light is mainly used as a light source. The laser may be a gas laser, a solid-state laser, a surface laser, or the like. A light emitting element such as an LED, a halogen lamp, or a flash lamp can be used as another light source.

The planar light barrier 2 can be formed by scanning the linear light from the light source with a reflecting means such as a polygon mirror or a deflecting means. Further, instead of scanning the linear light into a planar light, as shown in FIG.
A large number of light emitting elements 21 such as EDs and halogen lamps and a light condensing means 22 are arranged in an array, and a luminous flux 23 from each light emitting element
The planar light barrier 24 can also be formed by arranging.

Further, by providing a control means for changing the light emission amount of each light emitting element 21, it is possible to control the irradiation pressure of an arbitrary linear portion of the planar light barrier 2. In other words, control is provided in which a portion that forms linear light by irradiating light from the light emitting element 21 and holds fine particles, and a portion that reduces the amount of light from the light emitting element 21 or does not irradiate light to hold fine particles I do. By using this control, the image forming method described later can be used. Further, by combining two or more sets of linear light control means, it is possible to control the irradiation pressure at any one point on the light barrier.

FIG. 6 shows a method of controlling the light barrier in a dot shape. As shown in FIG. 6, the two light barrier forming devices 1 allow the light barriers 2 on the two surfaces to intersect each other in a V shape, and the fine particles can be held linearly on the line of intersection of light. And
When the light amount of any light emitting element of the light barrier forming devices 1a and 1b is reduced, only one point on the intersection line of the light barriers can be formed to have no light barrier. By reducing the light amount of an arbitrary light emitting element or providing the portion 25 which does not emit light, it becomes impossible to hold fine particles at the intersection of this portion. That is, by forming the portion 25 which is not irradiated with light based on the printing signal, it is possible to drop the particles on the image forming object and print the image.

As another embodiment of controlling the light barrier in a dot shape, the light barrier forming device 1a forms the light barrier substantially horizontally, and the light barrier forming device 1b forms the light barrier obliquely.
The particles are suspended along the light rays of the light barrier. In this case, the light barrier can be controlled in a dot shape by changing the light amount of the light barrier forming device 1a.

FIG. 7 is a diagram for controlling the light barrier in a dot shape. The light barrier forming devices 1a and 1b are arranged substantially orthogonal to each other, and light barriers on two surfaces are formed in an overlapping manner. The light-irradiated portions 26 and 27 and the light-unirradiated portion 28 are formed based on the printing signal, and the fine particles are dropped from the light-unirradiated portion 28 onto the image forming object, To print.

When the light amount of the light source is increased, the light pressure acting on the fine particles becomes stronger. FIG. 8 shows an example of an arrangement method of light sources used in the light barrier forming device. As shown in FIG. 8A, the light amount of the light ray 29 can be increased by arranging the two light sources at positions facing each other. Also,
As shown in FIG. 8B, the mirror 30 is placed at a position facing the light source.
Can be arranged to reflect the light ray 29 to increase the amount of light. Further, as shown in FIG. 8C, a filter 31 having a reflectance different depending on the incident direction of light is arranged in front of the light source, and the light is reciprocated between the mirror 30 and the filter 31 many times to reduce the amount of light. Can be increased. Also, the amount of light can be increased by using a photomultiplier tube.

In order to print an image, fine particles must pass through the light barrier and move onto the object to be imaged. As the image forming method, as described with reference to FIGS. 6 and 7, a part where the light is not irradiated is partially formed so that the light pressure for holding the fine particles on the light barrier is not generated.
There is a method in which fine particles are dropped by gravity or the like and attached to an object to be imaged. As a method of forming a part where the light is not irradiated or a part where the light amount is weak, there is a method of controlling the light amount of the light source and also a method of blocking the optical path by using a spatial modulator or the like. In addition, there is a method in which the air pressure in the upper part is slightly increased to positively drop the air to form a downward air flow.

As another image forming method, as described with reference to FIG. 1, there is a method of forming an image on an image forming object by pushing out fine particles from a light barrier using light pressure. Figure 1
The light source of the fine particle driving device 6 is arranged above the light barrier,
By irradiating the printing position with light, the fine particles are pushed out of the light barrier. When the method using the light pressure and the image forming method described with reference to FIGS. 6 and 7 are used together, the image can be printed more effectively. A laser or an LED array is preferable as a light source provided in the particle driving device 6.

When the light source is a laser, an optical scanning device such as a polygon mirror is also required. The fine particles on the light barrier are irradiated with light based on the printing signal to drive the fine particles. Also,
When the light source is an LED array, the fine particles are driven line by line. In this case, in FIG. 5, the image can be more effectively printed by extinguishing the light flux corresponding to the printing line. In addition to the method of pushing out the fine particles as described above, there is a method of pushing out the held fine particles instantly by using a condensing means, a deflecting element, a reflecting element, or the like.

FIG. 9 shows a method of pushing out fine particles using a deflecting element. Two light barrier forming devices 1a, 1
The light from b is irradiated from the two directions (d and e) through the deflection elements 32a and 32b, and the fine particles 18 are held on the line of intersection of the light barriers. Next, when the optical path from the light source 1b is changed by the polarization element 32b as e → f and an intersection is formed above the fine particles 18, a downward repulsive force acts on the fine particles. A desired image can be printed by performing the above-mentioned deflection operation for each printing dot. The operation principle of the deflection element includes one using the acousto-optic effect, one using the electro-optic effect, one using the magneto-optic effect, and the like.
In this embodiment, any element may be used.

FIG. 10 is a diagram showing a method of pushing out fine particles using a variable focus lens. By using the variable focus lens 35, the focal length of light is changed within the range of from infinity to the light barrier 2. When the focal length is infinite,
Since the light irradiates the range of the light rays 33a to 33b, that is, since it is not condensed, the amount of light hitting each fine particle is small and the fine particle cannot penetrate the light barrier. However, when the focus is changed to the surface of the light barrier 2, a strong light pressure acts on the fine particles 18 at the focus position, and the fine particles 18 are pushed out of the light barrier 2. A desired image can be printed by performing the focus changing operation for each printing dot.

FIG. 11 is a diagram showing still another embodiment. A mask 36 whose mask shape is controlled according to a print image signal is prepared above the light barrier 2, and light 37 from a light source such as a flash lamp is emitted from above. As a result, the fine particles that have received the pressure of the light that has passed through the mask 36 are pushed out of the light barrier 2 and adhere to the image forming object below. As the mask 36, a mask using a standard flat plate, a spatial modulator such as a liquid crystal panel displaying a printed image, or the like can be used.

FIG. 12 is a diagram showing another embodiment. A large number of light sources 38 that drive the fine particles are arranged in an array, and the light emitted from each light source 38 passes through the light collecting means 39 and is condensed on the fine particles existing on the light barrier 2 to generate a light pressure. The image is printed on the image forming object.

Instead of pushing the fine particles out of the light barrier by the light pressure or its own weight, the air pressure can be used to push out the fine particles in the light barrier to form an image on the image forming object. An air discharge nozzle is provided at a position substantially vertical to the horizontally formed light barrier, and a predetermined amount of air is discharged as necessary, whereby fine particles are pushed out of the light barrier and adhered onto the image formation target. By using this air pressure method in combination with the method described with reference to FIGS. 6 and 7, an image can be printed more easily.

Instead of light pressure, it is also possible to use an electric field to force the particles out of the light barrier. FIG. 13 is an explanatory diagram of adhering fine particles onto an image forming object by using electrostatic force. The fine particles 18 on the light barrier 2 are charged and charged, and on the other hand, an electric latent image 41 is formed on the image forming object 7 such as recording paper and is supplied below the light barrier 2. As a result, the fine particles 18 are attracted to the charge on the image forming object 7 by the electrostatic force and are attached to the recording paper. In addition, an electrode 42 is provided above the fine particles 18 and a charge having the same polarity as that of the fine particles 18 is generated on the surface of the electrodes 42 based on an image signal, so that a repulsive force is generated between the electrodes 42 and the fine particles 18. This repulsive force causes the fine particles to break the light barrier, so that an image can be printed easily. By changing the amount of charge applied to the electrode 42 according to the image signal, it is possible to print an image with gradation.

When a method of forming an image using light pressure, air pressure or static electricity is used, the light holding the fine particles may be extinguished only at the moment when the fine particles are pushed out of the light barrier. By extinguishing the light held, the light barrier disappears momentarily,
The fine particles easily move onto the image formation target. Therefore, the image can be printed more efficiently.

By combining the above image forming apparatuses in multiple stages, it is possible to color the printed image. Figure 14
It is a figure which shows an example which prints a color image. The light barrier forming devices 1b are arranged in multiple stages, the light barriers 2a from the light barrier forming devices 1a are crossed with the light barriers 2b from the respective devices 1b, and the color toner particles replenished from the fine particle supplying device 4 corresponding to each color are supplied. It is held near the intersection of the light barriers 2a and 2b. Magenta, cyan, and
Yellow and black particles are retained. The fine particles driven by the driving means 6 corresponding to each color move downward and adhere to the image forming object 7 such as recording paper. The fine particles not used for printing are collected by the fine particle collecting device 43 corresponding to each color.

Further, it is possible to print an image by using a plurality of light sources for driving fine particles by utilizing the difference in light reflectance depending on the wavelength of the substance. By changing the wavelength of light emitted from each light source, the substance that exerts the most repulsive force varies depending on each light source. FIG. 15 is a diagram showing an example of using this method. Fine particles 47, 4 in which the substance of the material is changed for each color
8, fine particles of a plurality of colors are mixed and held on the light barrier. Light from a plurality of light sources for driving fine particles corresponding to each color is collected in the same optical path by using the dichroic mirror 44, and each light source is operated based on an image signal to drive the fine particles. By this method, a multicolor image can be printed.

Although an example in which fine particles of an image forming medium such as toner are suspended and held in a space only by light pressure has been described, the fine particles are not held only by light pressure, but electromagnetic force, electrostatic force, or the like is used. It goes without saying that the fine particles can be more reliably retained on the light barrier by using other means together with the light barrier by light pressure.

[0040]

According to the present invention, the image forming medium particles are suspended and held in the space by using light pressure, and the suspended and held image forming medium particles are moved toward the recording medium. A desired image can be obtained.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a printing process of a conventional electrophotographic apparatus.

FIG. 3 is an explanatory view of the action of light pressure.

FIG. 4 is an explanatory view of the action of light pressure.

FIG. 5 is a diagram showing an example of a light barrier forming device using an array of light sources.

FIG. 6 is a diagram showing an embodiment in which two or more light barrier forming devices are combined.

FIG. 7 is a diagram showing another embodiment in which two or more light barrier forming devices are combined.

FIG. 8 is an explanatory diagram of an example of increasing the light amount.

FIG. 9 is a diagram showing an embodiment in which two light barrier forming devices are combined and light from one of them is deflected for printing.

FIG. 10 is a diagram showing an example in which light is condensed to move fine particles toward a recording medium.

FIG. 11 is a diagram showing an example using a mask.

FIG. 12 is a diagram showing an embodiment in which driving means is arranged in an array.

FIG. 13 is an explanatory diagram of a driving unit that uses an electric field.

FIG. 14 is a diagram illustrating an embodiment of a color image forming apparatus configured by combining printing devices in multiple stages.

FIG. 15 is a diagram showing an embodiment of a color image forming apparatus using a plurality of light sources having different wavelengths.

[Explanation of symbols]

1 ... Light barrier forming device, 2 ... Light barrier, 3 ... Fine particle group,
4 ... Particle supply device, 5 ... Particle recovery device, 6 ... Particle drive device, 7 ... Image forming object.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G03G 15/05 G03G 15/00 115 (72) Inventor Akira Arimoto 7-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 in Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Teruaki Mitsuya 7-1-1 Omika-cho, Hitachi City, Ibaraki Hitachi Incorporated Hitachi Research Laboratory in Hitachi Ltd. (72) Yoshito Tsunoda Hitachi City, Ibaraki Prefecture 7-1 Mitamachi, Hitachi Ltd. Hitachi Research Laboratory, Hitachi Ltd. (72) Inventor Nobuyoshi Hoshi, 7-1, Omikacho Hitachi City, Ibaraki Hitachi Ltd. Hitachi Research Laboratory, Hitachi Ltd.

Claims (26)

[Claims] 1. An image forming method of forming an image by adhering fine particles of an image forming medium to a recording medium, wherein light barriers are formed at spaced positions on the recording medium, and the fine particles of the image forming medium are layered on the light barrier. An image forming method, characterized in that the fine particles of the image forming medium on the light barrier at corresponding positions are extruded toward the recording medium through the light barrier and adhered to the recording medium according to the formed image. 2. In an image forming method for forming an image by adhering fine particles of an image forming medium to a recording medium, the light barriers of two surfaces are crossed and the fine particles of the image forming medium are suspended and held at the crossing position by the light pressure of the light barriers. Then, according to the formed image, the image forming medium fine particles on the light barrier at a corresponding position are extruded toward the recording medium side through the light barrier and adhered to the recording medium. 3. The image forming method according to claim 1 or 2, wherein the image forming medium particles are held on the light barrier by any one of electromagnetic force and electrostatic force in addition to the light pressure by the light barrier. Method. 4. The image forming method according to claim 1, wherein fine particles of the image forming medium at a corresponding position are extruded from the light barrier by the irradiation pressure of light. 5. The image forming method according to claim 4, wherein the irradiation pressure of the light is increased by adjusting the focal position of the lens through which the light passes to the fine particles of the image forming medium at the corresponding position. 6. The method according to claim 1, wherein the light pressure at the corresponding position of the light barrier is reduced or blocked and the image forming medium fine particles at the corresponding position are dropped onto the recording medium by its own weight. Image forming method. 7. The image according to any one of claims 1 to 3, wherein the optical path position at the corresponding position of the light barrier is shifted and the image forming medium fine particles at the position are dropped onto the recording medium by its own weight. Forming method. 8. The image forming method according to claim 1, wherein fine particles of the image forming medium at a corresponding position are extruded from the light barrier by air pressure. 9. The image forming method according to claim 1, wherein the light pressure is amplified by multiply reflecting the light of the light barrier. 10. The electrostatic latent image is formed on a recording medium according to claim 1, the image forming medium fine particles on the light barrier are charged with an electric charge opposite to the electrostatic latent image, and the electrostatic latent image is charged. An image forming method comprising developing an electrostatic latent image with fine particles of an image forming medium. 11. An image forming apparatus for forming an image by adhering fine particles of an image forming medium to a recording medium, and a light barrier forming means for forming a light barrier at spaced positions on the recording medium, and an image forming medium on the light barrier. It is provided with a fine particle supply device for supplying a fine particle group to float and hold it in a layered form, and a fine particle drive means for extruding image forming fine particles at a corresponding position according to a formed image toward a recording medium side through a light barrier and adhering to the recording medium. Image forming apparatus. 12. In an image forming apparatus for forming fine particles by adhering fine particles of an image forming medium to a recording medium, light barrier forming means for intersecting light barriers on two surfaces, and image formation at an intersection position of the light barriers on the two surfaces. Fine particle supplying means for supplying a medium fine particle group and floating and holding the image forming medium fine particles by the light pressure of the light barrier, and the image forming medium fine particles on the light barrier at a corresponding position according to the formed image to the recording medium side through the light barrier. An image forming apparatus comprising: a fine particle driving unit that pushes out and attaches the fine particles to the recording medium. 13. The device according to claim 11 or 12, further comprising means for holding the image forming medium fine particles on the light barrier by any one of electromagnetic force and electrostatic force in addition to the light pressure by the light barrier. Image forming apparatus. 14. The image forming method according to claim 11, wherein the fine particle driving unit pushes the fine particles of the image forming medium at a corresponding position from the light barrier by the irradiation pressure of light. apparatus. 15. The particle driving means according to claim 14, wherein the focus position of the lens that allows light to pass is aligned with the image forming medium particles at the corresponding position to increase the irradiation pressure of the light that pushes out the image forming medium particles. A characteristic image forming apparatus. 16. The fine particle driving means according to claim 11, wherein the fine particle driving means lowers or blocks the light pressure at the corresponding position of the light barrier and drops the image forming medium fine particles at the corresponding position onto the recording medium by its own weight. An image forming apparatus, characterized in that 17. The deflection device according to claim 11, wherein the fine particle driving means shifts an optical path position at a corresponding position of the light barrier to drop the image forming medium fine particles at the position onto the recording medium by its own weight. An image forming apparatus comprising means. 18. The image forming apparatus according to claim 11, wherein the fine particle driving unit pushes the fine particles of the image forming medium at a corresponding position from the light barrier by air pressure. 19. The image forming apparatus according to claim 11, wherein the light barrier forming unit includes a reflecting unit that amplifies light pressure by multiply reflecting the light of the light barrier. . 20. An image forming apparatus for adhering fine particles of an image forming medium to a recording medium to form an image, a means for forming a light barrier, and a group of fine particles of the image forming medium supplied on the light barrier to form a light barrier on the light barrier. It is provided with a fine particle supplying means for floating and holding in a layer form, a means for forming an electrostatic latent image on the recording medium, and a means for charging the image forming medium fine particles on the light barrier with a charge opposite to the electrostatic latent image. A characteristic image forming apparatus. 21. A plurality of image forming apparatuses according to any one of claims 1 to 20 are arranged, and a color image is formed in each image forming apparatus by using image forming medium fine particles of different colors. Image forming apparatus. 22. The color image is formed according to claim 1, wherein fine particles of a plurality of colors are used as fine particles of the image forming medium, and fine particles of the image forming medium of each color are selectively attached to a recording medium. An image forming apparatus characterized by: 23. The image forming apparatus according to claim 1, wherein the light barrier forming means scans linear light to form a planar light barrier. 24. The light barrier forming means according to claim 1, wherein a large number of light sources are arranged in an array and linear light is emitted from each light source to form a planar light barrier as a whole. An image forming apparatus characterized by being formed. 25. The image forming apparatus according to claim 1, further comprising a collecting unit that collects image forming medium particles remaining on the light barrier. 26. The image forming apparatus according to claim 1, further comprising a fixing unit that fixes the image forming medium particles on the recording medium to the recording medium.