JPS6095456A - Color image recording method - Google Patents

Abstract

PURPOSE:To easily execute synchronous control of imagewise exposure by using spot distribution exposure for imagewise exposure, and superposing the spot positions of the following imagewise exposure on the spot positions of the preceding imagewise exposure. CONSTITUTION:A recording apparatus is composed of developing devices 5, 6, 7, 8 using toners of different colors, such as yellow, magenta, cyan, and black, as developers; a pretransfer electrostatic charger 9, provided when needed, for facilitating transfer of a color image formed on an image forming drum 1 by superposing toner images of plural colors onto a recording material P; a pretransfer exposure lamp 10; a transferring device 11; a fixing device 12 for fixing the toner image transferred onto the recording material P; a destaticizer 13; and a cleaning device 14. As the charger 2, it is preferable to use a scorotron corona discharger capable of givng stable charge a little affected by the preceding charging, and as the imagewise exposing device 4, a laser beam scanner is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image recording method, and in particular, the present invention relates to a color image recording method, in which the surface of an image forming member is charged, image exposure is repeated at least, and development is performed using a developing device each time. The present invention relates to a color image recording method in which a plurality of color toner images are polymerized on an image forming member.

[Prior art]

As a color image recording method as mentioned above, Japanese Patent Application Laid-Open No. 1986-
Methods described in Japanese Patent Application Laid-open No. 144452, Japanese Patent Application Laid-open No. 58-116553, and Japanese Patent Application Laid-open No. 58-116554 are known. In all of these methods, repeated image exposure is performed by separate devices, and it is necessary to shift the subsequent image exposure position with respect to the previous image exposure position so that they do not overlap. This is a developing method in which toner charged to the same polarity is attached to an electrostatic image whose potential is lower than that of the background area and which is applied to the exposed area. Therefore, if image exposure is performed using spot distribution exposure using a laser beam scanner, for example, to record a color image such as a landscape painting, the spot positions of the image exposure for each color are shifted so that they do not overlap with each other, making it possible to spot a lively spot. There is a problem that the distribution density becomes coarse, and only color images that appear rough and faded can be recorded.Furthermore, the recording device becomes larger and more expensive, and the synchronization control of image exposure to the image forming body depends on the position of the image exposure device. There is also the problem that it becomes complicated because it involves

[Purpose of the invention]

The present invention provides a color image recording method that allows color images such as landscape paintings to be recorded with deep colors and fine details, and further allows a recording device to be configured in a small size and at low cost, and allows for easy synchronization control of image exposure. It is.

[Structure of the Invention] The present invention provides a color image in which a plurality of color toner images are superimposed on the image forming body by charging the surface of the image forming body, performing at least repeated image exposure, and developing with a developing device each time. In the recording method, the image exposure is spot distribution exposure,
A color image recording method characterized in that a spot position of a previous image exposure and a spot position of a subsequent image exposure are overlapped, and further, the above object is achieved by a configuration in which repeated image exposures are performed by the same device. has been achieved.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to illustrated examples.

FIG. 1 is a schematic diagram of the configuration of an example of a recording apparatus that implements the method of the present invention, FIG. 2 is a diagram of a schematic configuration of a laser beam scanner for image exposure, and FIG. 3 is a partial cross-section diagram of an example of a developing device. 4 to 7 are flowcharts of the method of the present invention carried out by the recording apparatus shown in FIG. 1, FIG. 8 is a schematic configuration diagram showing another example of the recording apparatus, and FIG.
The figure is a charging state change chart of the image forming body schematically showing the process of forming an electrostatic image in the recording device W of FIG. 8, FIG. 10 is a surface potential change chart of the image forming body, and FIGS. FIG. 14 is a flowchart of the implementation of the method of the present invention, each carried out by the recording device of FIG.

In the recording apparatus shown in FIG. 1, 1 is a drum-shaped image forming body having a photoconductive surface layer of Se or the like and rotating in the direction of the arrow; 2 is a charger that uniformly charges the surface of the image forming body 10; Reference numeral 3 denotes a light lamp that uniformly exposes the surface of the image forming body 10 with weak light, which is used in the examples shown in FIGS. 5 and 7, which will be described later; 4 is an image exposure device; Developing units 9 and 10 each using a different color toner such as black as a developer transfer a color image formed by superimposing a plurality of color toner images on the image forming member 1 onto the recording member P. In order to facilitate the transfer, a pre-transfer charger and a pre-transfer exposure lamp are provided as necessary; 11 is a transfer device;
12 is a fixing device that fixes the toner image transferred to the recording medium P; 13 is a set of one or both of a static elimination lamp and a corona discharger for static elimination; (5) a set (5) that contacts the surface after the image has been transferred and removes any residue on the surface; The cleaning device d includes a cleaning blade or a fur brush that removes toner and separates from the surface of the image forming body 10 when the surface on which the first development has been performed reaches the housing.

In the charging interval 2, there is a method shown in the figure that can provide stable charging with less influence from the previous charging, especially when the surface of the image forming body 1 is charged on top of the already charged surface. It is preferable to use a scorotron corona discharger such as The image exposure device 4 uses a laser beam scanner as shown in FIG.

Laser beam scanner in Figure 2, He-N.

A laser beam emitted from a laser 15 such as a laser is deflected by an acoustic optical modulator 16 using a mirror scanner 17 consisting of an octahedral rotating polygon mirror, and an image is formed through an imaging f-theta lens 18. Image exposure is formed by scanning the surface of the body 1 at a constant speed for each color. Note that 19.20 is a (6) mirror, and 21 is an imaging f-θ lens 18 in order to change the diameter of the beam on the image forming body 1 as described later.
This is a lens device that changes the diameter of the beam incident on the beam.

Furthermore, the developing devices 5 to 8 preferably have a structure as shown in FIG. 3.

In FIG. 3, 22 is a developing sleeve made of a non-magnetic material such as aluminum or stainless steel, 23 is a magnet body provided inside the developing sleeve 22 and has a plurality of magnetic poles in the circumferential direction, and 24 is a magnet body provided on the developing sleeve 22. A layer thickness regulating blade 25 regulates the thickness of the developer layer formed; 25 is a scraper blade that removes the developed developer layer from above the developing sleeve 22; 26 is a stirring rotation that stirs the developer in the developer reservoir 27; 28 is a toner hopper; 29 is a toner replenishment roller having a recess on its surface into which toner enters; and 30 is a vibration component in the developing sleeve 22 via a protective resistor 31; In some cases, apply a bias voltage to the developing sleeve 2.
This is a power source for forming an electric field to control the movement of the toner between the developing sleeve 22 and the image forming body 1, and FIG. 11 shows that the developing sleeve 22 and the magnet body 23 rotate in the directions of the arrows. , even if the developing sleeve 22 is fixed,
Even if the magnet body 23 is fixed or the developing sleeve 2
2 and the magnet body 23 may rotate in the same direction. When the magnet body 23 is fixed, it is usually strongly magnetized [7], or it has the same or different polarity in order to make the magnetic flux density of the magnetic pole facing the image forming body 1 larger than the magnetic flux density of other magnetic poles. Two magnetic poles may be placed close to each other.

In such a developing device, the magnetic pole of the magnet body 23 is usually 500 to 500.
It is magnetized to a magnetic flux density of 1500 Gauss, and the developer in the developer reservoir 27 is attracted to the surface of the developing sleeve 22 by the magnetic force, and the attracted developer is transferred to the layer thickness regulating blade 2.
4 to form a developer layer whose thickness is regulated, and the developer layer moves in the same direction or in the opposite direction to the direction of the rotation arrow of the image forming body 1, so that the surface of the developing sleeve 22 is regulated by the direction of the rotation arrow of the image forming body 1.
The electrostatic image on the image forming body 1 is developed in a developing area facing the surface of the developing sleeve 22, and the remaining portion is removed from the surface of the developing sleeve 22 by a scraper blade 25 and returned to the developer reservoir 27. The development is repeated in order to superimpose color toner images, and at least from the second development onwards, it is necessary to avoid displacing the toner attached to the image forming body 1 in the previous development in the subsequent development. It is preferable to use non-contact jumping development conditions. FIG. 3 shows a state in which development is performed under non-contact jumping development conditions.

Furthermore, in the developing units 5 to 8, non-magnetic toner is used, which does not require the inclusion of a black or brown magnetic substance in the toner and can obtain a toner with a clear color, and can easily control the charging of the toner. It is preferable to use a so-called two-component developer consisting of a mixture of a magnetic carrier and a magnetic carrier. In particular, the magnetic carrier is triiron tetroxide in resins such as styrene resins, vinyl resins, ethyl resins, rosin modified resins, acrylic resins, polyamide resins, epoxy resins, and polyester resins.

(9) γ-ferric oxide, chromium dioxide, manganese oxide.

Ferrite, manganese-copper alloy, etc., containing dispersed particles of ferromagnetic or paramagnetic material, or
The surface of magnetic particles is coated with the resin as described above, and the resistivity is 10'Ωm or more, preferably 10'Ωm or more.
Preferably, the insulating carrier has a resistance of 1 sΩ or more.

If this resistivity is low, when a bias voltage is applied to the developing sleeve 22, charges are injected into the carrier particles.
Problems arise in that carrier particles tend to adhere to the surface of the image forming body and that a sufficient bias voltage is not applied. In particular, if the carrier adheres to the image forming body 1, the tone of the color image will be adversely affected.

The resistivity was determined by placing the particles in a container with a cross-sectional area of 0.50 cIL2, tapping them, applying a load of I Ky/α2 on the packed particles, and applying a voltage of 1000 V/α2 between the load and the bottom electrode. This value is obtained by reading the current value when applying a voltage that generates an electric field of α.

(10) Furthermore, if the average particle size of the carrier is less than 5 μm, the magnetization will be too weak, and if it exceeds 50 μm, the image will not be improved, breakdown or discharge will easily occur, and high voltage will not be able to be applied. , the average particle size is 5 μm or more and 40 μm
m or less, and if necessary, a suitable amount of a flow agent such as hydrophobic silica may be added as an additive.

The black toner used is the same as that used in conventional two-component developers, the cyan toner is made by adding copper phthalocyanine to black carbon black, and the magenta toner is the same. For the yellow color of polytan dust added with phosphoric acid, those added with sulfur derivatives are also used. However, the toner is not limited to such colored toners using pigments, and colored toners using dyes may also be used, and it goes without saying that a charge control agent or the like may be added as necessary.

The toner preferably has an average particle size of 1 to 20 μm, and an average charge amount of 3 to 300 μ0/f7! ,
Particularly preferred is one of 10 to 100 μc/f.

When the average particle size of the toner is less than 1 μm, it is difficult to separate from the carrier, and when it exceeds 20 μm, the resolution of the image decreases.

When a developer made of a mixture of an insulating carrier and toner as described above is used, the bias voltage applied to the developing sleeve 22 in FIG.
1 to 1, the setting can be easily performed without fear of leakage so that fog does not occur. In addition, in order to more effectively control the development movement of the toner by applying such a bias voltage, the toner may also contain a magnetic material similar to that used in magnetic carriers to the extent that color clarity is not impaired. It's okay.

The configurations of the developing device and developer preferably used in the method of the present invention have been described above, but the present invention is not limited thereto.

58-116553 to 116554 @ The developing device and developer described in each publication may be used, and more preferably, the applicant of the present application previously filed the patent application No. 58-5
No. 7446, No. 58-96900-96903, No. 5
It is preferable to perform non-contact jumping development using a two-component developer using a developing device and developer as described in each specification of No. 8-97973.

The method of the present invention as shown in FIGS. 4 to 7 can be carried out using the recording apparatus as described above. Incidentally, FIGS. 4 to 7 all show the stage up to the second development.

FIG. 4 shows that in the recording apparatus of FIG. 1, a charge is applied to the surface of the image forming body 1 in an initial state where the electric potential is O after being neutralized by the static eliminator 13 and cleaned by the cleaning device 14.
At the first time, a first charge is applied uniformly by the charger 2, and a first image exposure for each color is applied to the charged surface by an image exposure device M4 as shown in FIG. A degraded electrostatic image is formed, and the electrostatic image is first developed by one of the developing devices 5 to 8, which uses a color toner corresponding to the first image exposure as a developer to form an image. The color toner frictionally charged to the same polarity as the charge on body 1 adheres to the first
The potential of the electrostatic image due to rotational exposure rises to near the background potential, but this is because an electrostatic image cannot be formed even if image exposure is performed again on that part (13), so the image forming body 1 with the static eliminator 13, or without removing the static electricity with the charger 2 again in the second rotation.
, and then the same image exposure device 4 as before.
A second imagewise exposure is carried out with the same spot density and at least a partial overlap as the previous imagewise exposure, and then by another developer using a color toner corresponding to the second imagewise exposure as a developer. 2nd development [7, similarly below, 3rd development, 4th development]
A color image in which a plurality of color toner images are superimposed is formed on the image forming member 1 by repeating charging, image exposure, and development, and the color image has passed from the stage where the fourth development is performed. One or both of the pre-transfer charger 9 and the pre-transfer exposure lamp 10 are operated as necessary until the color image is transferred to the recording medium P which is fed in synchronization with the rotation of the image forming body 1 by the transfer device 11. Then, the transferred color image is fixed on the recording medium P by the fixing device 12, and the surface of the image forming body 1 to which the color image has been transferred is neutralized by the N remover 13, and cleaned by the cleaning device 14 (14). This figure shows an embodiment of the recording method of the present invention in which one cycle of color image recording is completed by returning to the initial state by changing the color image. In this way, by making each image exposure so that the spot positions at least partially overlap, it is possible to prevent a decrease in the pixel density of the formed color image, and therefore, the color image can be recorded with deep colors and fine details. be able to. The reason why an electrostatic image with a lower potential than the background potential is formed at a position different from the position to which toner T was previously attached during the second image exposure is because toner T is attached to the color image. This is because it shows the case where there is no pixel of color. T' is the toner attached during the second development. Although the figure shows a case where the spot positions of each image exposure are completely overlapped, they may be partially overlapped. Also,
In the method of the present invention, as described above, electrostatic image formation can be performed each time using the same device, so the recording device can be configured in a small size, the cost can be reduced, and the synchronization control of image exposure can be easily performed. .

In FIG. 5, the example up to the first development is the same as the example in FIG. 4, but after the first development, the image forming body 1 is Either the surface is uniformly exposed and then charged a second time using the charger 2, or the surface is first charged for the second time using the charger 2 and then exposed uniformly and weakly using the exposure lamp 3. The electrostatic image forming area to which the electrostatic image is attached is brought into a state where it is easy to form an electrostatic image with a potential slightly higher than that of the background area, and then a second image exposure and a second development are performed in the same manner as the example in FIG. 4 shows an embodiment of the present invention that differs from the example shown in FIG. 4 in that a color image is formed by repeating the third and fourth image exposure and development. In this example, the later toner T' is applied on the earlier toner T.
Suitable when you do not want to have any adhesion. In other words, many general images require high reproducibility of black characters, but by using this method, by writing the black characters first, it is possible to prevent the next overlapping color toner from adhering to the color toner. Prevents lumps and misalignment. In this way, an image is obtained in which the prioritized colors are emphasized. -! Furthermore, in combination with the example of FIG. 4, a specific color image can be emphasized or weakened. Of course, after the first development and before starting the next process, static elimination and charging steps may be performed.

FIGS. 6 and 7 show that when the later toner T' is deposited on top of the earlier toner T as in FIGS. 4 and 5,
The mixing condition of the color toners changes depending on the fixing method and the order of color overlapping, and the color balance changes, so the problem of mixing was improved by attaching the later toner T' around the earlier toner T. 1 shows an embodiment of the invention.

The examples in FIGS. 6 and 7 correspond to the examples in FIGS. 4 and 5, respectively, and the spots of the second image exposure, that is, the subsequent image exposure, are This embodiment differs from the examples shown in FIGS. 4 and 5 in that the lens device 20 of the laser beam scanner is large enough to surround the spot of the first image exposure, that is, the previous image exposure.

In the examples shown in FIGS. 6 and 7, it is possible to prevent the pixel density of the formed color image from decreasing, and therefore, the color image can be recorded with deep color and fine detail, and the problem (17) of toner mixing can be avoided. Furthermore, in these cases clear color images can be recorded. In particular, in the example shown in FIG. 7, compared to the example shown in FIG. <<, since the subsequent toner T' adheres only around the previous spot, toners T and T' do not mix in the area where the spots overlap, resulting in a cloudy color mixture. You can get beautiful mixed colors.

In the examples shown in FIGS. 4 and 5, since toner mixing occurs, the order of the colors in development greatly affects the clarity of the color image, and therefore it is important to determine the order of development. However, in the examples of FIGS. 6 and 7, the order of development is not as important as in the examples of FIGS. 4 and 5. However, the tone of the color image is still affected by how the colors are distributed from the center to the outside.

The above is a developing method in which all the development by the developing devices 5 to 8 causes toner charged to the same polarity as the background potential to adhere to the electrostatic image corresponding to the exposed area where the potential is lower than the background potential. However, according to the recording apparatus shown in FIG. 8, the development in the method of the present invention is performed by a developing method in which toner charged to the opposite polarity to the electrostatic image is attached to the electrostatic image. I can do it.

The recording apparatus shown in FIG. 8 differs from the recording apparatus shown in FIG. 1 in that the drum-shaped image forming member 1' has a structure in which a transparent insulating surface layer is further provided on the surface of the developing member 1 shown in FIG. In a certain point, in place of the charger 2 in FIG. 1, a primary charger 32 consisting of a combination of an exposure lamp and a corona discharger (the exposure lamp may be omitted if the photoconductor is capable of charge injection) and a corona discharger are used. The point is that a secondary band 1M consisting of a discharger and a vessel 33 are provided,
The rest is the same as in the recording apparatus shown in FIG. Therefore, the same functional parts as in FIG. 1 are designated by the same reference numerals. In addition, the negative charger 32 and the secondary charger 33
It is preferable to use a scorotron corona discharger as shown in the figure.

In this recording apparatus, the surface of the image forming body 1', which has been neutralized, is irradiated with the exposure lamp of the primary charger 32 (as mentioned earlier, there are cases where irradiation with the exposure lamp is not required). When charged with a discharger, the imaging member 1' is coated with the photoconductive photosensitive layer 1'b and the transparent insulation coating If! #1'
The surface of 0 has a charge as seen in Figure 9A. When the secondary charger 33 performs corona discharge on the surface of the charged image forming body 1', since the photoconductive photosensitive layer i'b is insulating, the transparent insulating surface layer 1'0 is Only the surface charge decreases, and the charge on the image forming member 1' changes as shown in FIG. 9B. When image exposure light is incident on the surface of this secondarily charged image forming body 1', the photoconductive photosensitive layer i in the exposed area PH
Since the surface charge of 'b decreases and the original charge remains in the non-exposed area DA, the charge of the image forming member 1' changes as shown in FIG. 9O. FIG. 10 shows the changes in the surface potential of the image forming body 1' during this period, and the potentials in states A, B, and 0 in FIG.
This corresponds to the charging states shown in Figures A, B, and O. In other words, the potential of the exposed area PH where the imagewise exposure is incident is the surface potential shown by 0 (PH) in FIG. 10, whereas the potential of the unexposed area DA where the imagewise exposure is not incident is as shown in FIG. What is the surface potential indicated by B? Since they are the same 0 (DA), an electrostatic image with a surface potential indicated by 0 (PH) is formed by image exposure with respect to this background potential. This electrostatic image can be developed by Coulomb attraction using a developer that charges the exposed area PH to a polarity opposite to that of the latent image, as in a normal electrophotographic copying machine. Note that 1'a is a conductive substrate made of aluminum or the like.

With the recording apparatus shown in FIG. 8 as described above, the method of the present invention shown in FIGS. 11 to 14, in which development is performed by Coulomb attraction, can be carried out. In addition, the first
1 to 14 also show the stage up to the second development.

FIG. 11 shows that in the recording apparatus of FIG.
The surface of the image forming body 11 whose potential is 0 is primarily charged as described above by the primary charger 32, and then the surface is secondarily charged by the secondary charger 33. A first image exposure is carried out using an image exposure device 4 similar to (21), and an electrostatic image in which the absolute value of the formed potential is larger than that of the background potential is formed in a color corresponding to the first image exposure. The toner charged to the opposite polarity to the electrostatic image is first developed by any one of the developing devices 5 to 8, which is used as a developer, and this developed electrostatic image forming area is charged to the opposite polarity. Polarly charged toner adheres and the surface potential decreases, and an electrostatic image is not formed there even if only image exposure is performed. A discharge is applied to the surface of the image forming member 1' so that an electrostatic image is also formed on the previously developed electrostatic image forming area, and then the same image exposure device f4 is used again to perform the previous image exposure. Second image exposure 17 so that the positions of the same spot overlap at least partially.
Then, the charging characteristics of the color corresponding to the second image exposure are developed using another developer using the same toner as the developer in the first development, and the same applies to the third and fourth image exposures. After image formation and development are repeated and a color image is formed, one cycle of color image recording is completed in the same way as in the examples of FIGS. 4 to 7. It shows. According to this example, since all development is performed by attaching toner charged to the opposite polarity to the electrostatic image, it is easier to control the developer density of each color than in the examples shown in FIGS. 4 to M7. It's easy.

FIG. 12 shows that not only secondary charging is performed by the secondary charger 33 after the first development until the second image exposure, but also primary charging is performed by the primary charger 32 before that. This embodiment shows an embodiment of the present invention that differs from the example shown in FIG. 11 in that the charge is removed by the charge remover 13 before the negative charge. According to this example, toner T' can be later deposited on the previously deposited toner T with the same density.

Figures 13 and 14 show the second image exposure as shown in Figures 6 and 7.
11 and 12 are shown examples of the method of the present invention that are different from the examples shown in FIGS. 11 and 12 in that the spot diameter is changed as in the example shown in the figure. According to these examples, similar to the examples shown in FIGS. 6 and 7, results such as no turbidity due to color mixing can be obtained.

Next, the embodiments shown in FIGS. 4 to 7 and the embodiments shown in FIGS. 11 to 14 described above will be explained more specifically as Example 1.
This will be explained as 8.

Example 1 The recording apparatus shown in FIG. 1 was used. However, the exposure lamp 3 was not used, and the image forming body 1 had an Ss photoreceptor surface layer, and its peripheral speed was 180 degrees/sea. This image forming body 10
The surface was charged to +500 ■ by charging n2 using a scorotron corona discharger, and the charged surface was charged by a laser beam scanner using a He-Ne laser as shown in Figure 2.
A first image exposure was carried out at a density of 6 spots/m.

As a result, an electrostatic image was formed on the image forming body 1 in which the potential of the exposed part was +30V with respect to the potential of the background part of +500V. This electrostatic image was first developed using a developing device 5 as shown in FIG.

The developing device 5 contains 50 wt% magnetite dispersed in the resin, with an average particle size of 30 μm and a magnetization of 30 emu/fz.
A developer consisting of a carrier having an ffl resistivity of 1014 Ω or more and a nonmagnetic toner having an average particle size of 10 μm, which is made by adding 10 parts by weight of a benzidine derivative as a yellow pigment to a styrene-acrylic resin and other charge control agents, is used as a toner. It was used under conditions such that the ratio of 20 wt % to the carrier was 20 wt %.

Further, the outer diameter of the developing sleeve 22 is 30 mm, the rotation speed is 100 rpm, the magnetic flux density of the N and S magnetic poles of the magnet body 23 is 1000 Gauss, the rotation speed is 11000 rpm, the thickness Q of the developer layer in the developing area, 7 mm, the gap between the developing sleeve 22 and the image forming body 1 is 0.8 mm, and the developing sleeve 22 is +400 mm.
Non-contact jumping development conditions were used, in which a superimposed voltage of a DC voltage (2) and an AC voltage of 1.5 kHz, 1000 V was applied.

While the electrostatic image is being developed in the developing unit 5, the other
Developing units 6 to 8 as shown in the figure were kept in a non-developing state. This can be done by disconnecting the developing sleeve 22 from the power source 30 and leaving it in a floating state, or by grounding it, or by actively charging the developing sleeve 22 with a polarity opposite to that of the image forming member 1 (25), that is, the polarity is also opposite to that of the toner. This is achieved by applying a polar DC bias voltage, and it is particularly preferable to apply a DC bias voltage. Since the developing devices 6 to 8 are also designed to perform development under non-contact jumping development conditions like the developing device 5, the developer layer on the developing sleeve 22 does not need to be particularly removed.

This developing device 6 uses a developer in which the toner in the developing device 5 is changed to a toner containing polytungstophosphoric acid as a magenta pigment instead of a yellow pigment.
For 117, a developer is used in which the toner is changed to a toner containing cyan pigment and 17 is copper phthalocyanine, and in developer 8, the toner is also changed to a toner containing carbon black as a black pigment. A drug was used. Of course, color toners based on other pigments or dyes can be used, and as mentioned above, the order of the colors to be developed and the order of the developing devices can also be appropriately determined.

The pre-transfer exposure lamp 1 is applied to the surface of the image forming body 1 that has been subjected to the first development, while removing (26) electrical equipment 13. Without operating the cleaning device 14, the charger 2 performs a second charge to +500V in the second rotation, and then the same laser beam scanner overlaps the spot positions and performs a second image exposure with the same spot density. Then, a second development of the magenta toner was performed using the developing device 6. Similarly, the third development of cyan toner using developer 7 and the fourth development of black toner using developer 8 were repeated.

For each of the above-mentioned developments, the amplitude 1 frequency 1 of the DC bias component and AC component of the voltage applied to the developing sleeve 22 is adjusted appropriately according to changes in the surface potential of the image forming body 1, development characteristics, color reproducibility, etc. The development density of each color can be adjusted by changing the selection time etc. of the time selection conversion.

When the fourth development is performed and a four-color image is formed on the image forming body 1, the pre-transfer band is made to be easily transferred by the device 9 and the pre-transfer exposure lamp 10, and then recorded by the transfer device 11. The image was transferred to the body P and fixed by the fixing device 12. The image forming body 1 on which the color image has been transferred is neutralized by the #electronic device 13, residual toner is removed from the surface by contact with the cleaning blade or fur brush of the cleaning device 14, and the surface on which the color image has been formed is cleaned. One cycle of color image recording has been completely completed at the time the film passes through the device 14.

Although the color images recorded in the above manner showed muddiness due to color mixing, the density of spot pixels was high, and the designs were delicately expressed.

Example 2 The same recording apparatus as in Example 1 shown in FIG. 1 was used. However, in this case, an exposure lamp 3 is provided.

Then, the first development was carried out under exactly the same conditions as in Example 1, except that a superimposed voltage of +400 cm DC voltage and 2 kHz, 1000 V AC voltage was applied to the developing sleeve 21 during development. Ta. Then, in the second rotation, a charger 2 is applied to the surface of the image forming body 1 that has been subjected to the first development.
2nd charge to +600V, and then uniformly expose the surface to weak light using exposure lamp 3 to raise the surface potential to +500V.
I made it. As a result, the surface potential of the portion to which toner T was attached during the first development was slightly higher than +500V. Therefore, the surface of this image forming body 1 was subjected to second image exposure and second development in the same manner as in Example 1. The above charging, uniform weak exposure, image exposure, and development were repeated for the third and fourth times, and color image recording was performed in the same manner as in Example 1.

The recorded color image is as delicate as that of Example 1, except that the color tone in the color mixture area appears to be slightly emphasized compared to that of Example 1. It was expressed in

In this example, instead of charging and uniform weak exposure, the same effect can be obtained by performing uniform exposure using the pre-transfer exposure lamp 10 or the exposure lamp of the static eliminator 13 and then charging with the charger 2. Effects can be obtained.

Example 3 The same recording device as in Example 1 was used. Then, by switching by the lens device 21 of the laser beam scanner, the first
The circular image exposure was a spot with a diameter of 20 μm, the second image exposure was a spot with a diameter of 30 μm, (29) the third image exposure was a spot with a diameter of 40 μm, and the fourth image exposure was a spot with a diameter of 50 μm, at the same spot position. , same 1
Performed at a density of 6 spots/simplified, resulting in +600■
An electrostatic image of +50 V is formed with respect to the background potential of , and during development, a superimposed voltage of +450 V DC voltage and 1.5 kHz, 1000 V AC voltage is applied to the developing sleeve 22 to produce black.

A color image was recorded in exactly the same manner as in Example 1, except that cyan, red, and yellow toners were superimposed in this order.

The recorded color image had a delicate and clear tone with almost no turbidity due to color mixture.

In this example, the same color image can be obtained even if the charging between the first development and the second image exposure, that is, the charging between the previous development and the next image exposure, is omitted.

Example 4 The same recording device as in Example 2 was used. Then, image exposure was performed in the same manner as in Example 3 to form the same electrostatic image, and during development, the developing sleeve 22 (30) was exposed to a DC voltage of +450 V and 2 kHz, 500 V.
A color image was recorded under exactly the same conditions as in Example 2, except that a superimposed voltage of AC voltage was applied.

The recorded color image was almost the same as that in Example 3, and had a delicate and clear tone.

Example 5 The recording apparatus shown in FIG. 8 was used. The image forming body 1' has a thickness of 30
μm 0 (18) A transparent insulating surface layer with a thickness of 20 μm is provided on the photoreceptor layer, and the peripheral speed is 180 m /
Sea. This image forming body 1' was uniformly exposed to light using an exposure lamp of a primary charger 32, and was primarily charged using a DC scorotron corona discharger so that the surface potential became +1000 VK. Next, a secondary band consisting of a corotron corona discharger was charged with an alternating current component using a device 33 so that the surface potential of the image forming member 1' became 1100 cm. H on this charged surface
The first image exposure was performed using the laser beam scanner shown in Fig. 3 using an e-Ne laser at a density of 16 spots)/ss, and an electrostatic image showing a potential of +200 μ against a background potential of −100 μ was obtained. W was formed. This electrostatic image was developed by applying an AC voltage of 1.5 kHz and 1000 V to the developing sleeve 22, and the developing device was developed under the same conditions as in Example 1, except that the charged polarity of the toner was opposite to that of the electrostatic image. 5, the first development 1~, and in this case, the image forming body 1
In the second rotation of ', secondary charging was performed again by the secondary charger 33, and then second image exposure and second development were performed in the same manner as in Example 1. Thereafter, secondary charging, image w1 light, and development were repeated 2 in the same manner as in FIGS. 3 and 4, and then a color image was recorded in the same manner as in Example 1.

In this example, since development is performed by Coulomb attraction, the density of the recorded color image can be adjusted more easily than in Examples 1 to 4, which use a development method in which toner charged with the same polarity is attached to the electrostatic image. The resulting and recorded color image had a similar tone to that of Example 1.

Example 6 The image forming body 1' has a transparent insulating surface layer with a thickness of 10 μm on an α-8i photoreceptor layer with a thickness of 10 μm. Charger 3
In 3, it is secondarily charged to O■, and in image exposure using a laser beam scanner, it becomes
The first time was +300 V, and the second and subsequent times were made to form a similar electrostatic image, and the voltage applied to the developing sleeve 22 during development was +1001 D DC voltage and 500 Hz,
As a superimposed voltage of 400 V AC voltage, before the second and subsequent image exposures, the static eliminator 13 performs static elimination, the negative charger 32 performs the above-mentioned primary charging, and the secondary charger 33 performs the above-mentioned secondary charging. A color image was recorded under the same conditions as in Example 5, except that K was changed to apply charging.

In this example, the tone of the recorded color image was similar to that of Example 1, and the density of each color could be further adjusted.

Example 7 Image exposure using a laser beam scanner was carried out in the same manner as in Example 3, the first time using a spot with a diameter of 20 μm, and the second time using a spot with a diameter of 20 μm.
The spot has a diameter of 30 μm for the first time, and the spot has a diameter of 40 μm for the third time.
m spot, the 4th spot is a straight (33) spot with a diameter of 50 μm, and the same spot position.

The procedure was carried out at the same density of 16 spots/fnm, except that an electrostatic image with a potential of +-400V was formed against a background potential of -100V, and black, cyan, red, and yellow toners were superimposed in this order. A color image was recorded under exactly the same conditions as in Example 5.

The recorded color image had a similar tone to that of Example 3, but the tone was clearer.

In this example as well, it is of course possible to easily adjust the density of each color.

Example 8 Image exposure by a laser beam scanner was performed using the same spots and spot densities as in Example 7, and an electrostatic image with a potential of +300 V was formed each time by applying the same spot and spot density as in Example 7. A color image was recorded under the same conditions as in Example 6 except for the following.

The recorded color image was almost the same as that of Example 7.

(34) It goes without saying that the density adjustment of each color can be easily performed in this example as well.

〔Effect of the invention〕

According to the present invention, it is possible to make the spot density finer and record fine color images, and it is also possible to record color images with clear tones without causing color mixing. Furthermore, since the electrostatic images are formed by the same device, the recording device can be made compact and inexpensive, and it is easy to control the synchronization of the image exposure to the image forming body. Effects can be obtained.

The present invention can also be applied to belt-shaped or sheet-shaped image forming bodies, or to those in which the image forming body is mounted on a substrate such as electrofax paper, and The color image formed by the toner may be fixed without being transferred.

In that case, it is highly necessary to consider the order in which the color toners are stacked, but on the other hand, there is an advantage that a pre-transfer lamp, transfer device, cleaning device, etc. are not required. However, the pre-transfer lamp and the static eliminator can be omitted if the toner has a specific polarity and charge 'kk' and is to be transferred. In addition to corona transfer, transfer also includes
Bias roller transfer, adhesive transfer, or pressure transfer via an intermediate transfer member may be used.

Of course, fixing is not limited to heat roller fixing.

The methods shown in Examples 5 to 8 of the present invention have a great advantage in that the polarity of the potential in the image area and the non-image area can be reversed, depending on the balance between the strengths of the negative charge and the secondary charge. ,
Of course, it is possible to develop them by making them the same polarity and changing the developing bias conditions. At this time, the potential is determined by shifting the Ovt position upward or downward in FIGS. 7 to 12. If the developing bias is changed accordingly, similar development is possible. , these methods are NP method, KIP method
Needless to say, this can also be applied to law.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the configuration of an example of a recording device that implements the method of the present invention, FIG. 2 is a schematic diagram of the configuration of a laser beam scanner for image exposure, and FIG. 3 is a partial cross-sectional view of an example of a developing device. , FIGS. 4 to 7 are flowcharts of the method of the present invention carried out by the recording apparatus shown in FIG. 1, FIG. 8 is a schematic configuration diagram showing another example of the recording apparatus, and FIG.
The figure is a charging state change diagram of the image forming body schematically showing the electrostatic image formation process in the recording apparatus of FIG. 8, FIG. 10 is a surface potential change chart of the image forming body, and FIGS.
FIG. 4 is a flowchart of the implementation of the method of the invention, each carried out by the recording device of FIG. 8. 1.1'... Image forming body, 2... Charger, 3...
Exposure lamp, 4... Image exposure device, 5-8... Developing device, 9... Pre-transfer charger, 10... Pre-transfer exposure lamp, 11... Transfer device, 12... Fixing Vessel, 13・
...Static eliminator, 14...Cleaning device, 15...
Laser, 16... Acousto-optic modulator, 17... Mirror scanner, 18... Imaging f-theta lens, (37) 19, 20... Mirror, 21... Lens device, 2
2...Developing sleeve, 23...Magnet, 24...
Layer thickness regulating blade, 25... Scrap bubble l/-de, 26... Stirring rotor, 27... Developer reservoir, 28
... Toner hopper, 29 ... Toner supply roller,
30...Power supply, 31...Protection resistor, 32...-
Secondary charger, 33...Secondary charger. Patent applicant Konishiroku Photo Industry Co., Ltd. Kinsha -55,-' (38) Curse 2 Figure 4 Figure 3 Figure 11 Figure 1'1. Figure 13 JP-A-95456 (15) Figure 141 Procedural Amendments October 1982 Kazuo Wakasugi, Commissioner of the Patent Office To '° 8'' 0 people' F,-E Image Seki 0. Way 3, Relationship with the case of the person making the amendment Patent applicant: v'f, C7 M”L (name) 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo (127) Konishiroku Photo Industry Co., Ltd. 5
, Date of amendment order Voluntary 6, Number of inventions increased since the amendment None 7, Column for detailed explanation of the invention in the specification subject to amendment and drawings 8, Contents of amendment (1) Specification No. 13, Line 14 Correct the "potential relative to the background potential" to 1--the potential of the exposed portion PH relative to the background potential of the non-exposed portion DA. (2) "Potential lower than background potential" on page 15, line 9
[The potential of the exposed area PH is corrected to be -1 lower than the potential of the unexposed area DA. (5) Insert the following after "Different." on page 17, line 17. [In addition, the non-exposed area DA and exposed area P in the 2nd Priesthood Light
The divisions of H are shown in 1-2 for the cases where the spot of the 21st Jl image exposure is solid and ring-shaped.
ing. (4) In the first line of No. 221, ``The absolute value of the potential is the background potential'' is corrected to ``The absolute value of the potential of one exposed area PH is the background potential of the non-exposed area DA''. (5) Figures 4 to 7 and 11 to 14 of the drawings
Revise the figure as shown in the attached sheet. (2) JP-A-95456 (19) Procedural amendment January 1980//Date Manabu Shiga, Commissioner of the Japan Patent Office 1, Indication of case 1987 Patent No. 187000 3, Make amendments Relationship with the patent case Patent applicant address 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name
(127) Roku Konishi Photo Industry Co., Ltd. 6, Number of inventions increased by amendment 07, Subject of amendment Column 88 for detailed explanation of the invention in the specification Contents of amendment (1) Page 10, line 17, 1 of the specification "With a load" is corrected to "with an electrode that also serves as a load body." (2) "1-40μm" on page 11, line 5 of the same page is 150μ
Correct it to "m". (3) In the 4th line of page 19, the phrase ``performed according to 1'' is corrected to ``performed according to the same.'' (4) Add "component only" next to "1 AC voltage" on the second line of page 32. (2)

Claims (1)

[Scope of Claims] (1) A color image in which a plurality of color toner images are superimposed on the image forming body by charging the surface of the image forming body, performing at least repeated image exposure, and developing with a developing device each time. A color image recording method, characterized in that the imagewise exposure is spot distribution exposure, and the spot position of the previous imagewise exposure and the spot position of the subsequent imagewise exposure are overlapped. (2) The color image recording method according to claim 1, wherein the spot diameter of the imagewise exposure of the light and the spot diameter of the subsequent imagewise exposure are changed. (5) The color image recording method according to claim 1 or 2, wherein the repeated image exposures are performed by the same device. (4) The color image recording method according to any one of claims 1 to 5, wherein charging is performed each time before the repeated image exposure. (5) The development is carried out under the conditions that the developer layer formed by the developing device is not brought into contact with the surface of the image forming body.
4. Color image recording method according to items 4 to 4.