JPS6076766A - Recording method of color image - Google Patents

Abstract

PURPOSE:To reduce the size and cost of a device by forming repeatedly an electrostatic image by the same device to an image forming body having a photoconductive sensitive layer and repeating formation and development of the electrostatic image thereby obtaining the color image. CONSTITUTION:The surface of an image forming body 1 which is destaticized by a destaticizer 13 and is cleaned by a cleaning device 14 is subjected to the 1st electrostatic charge by a charger 2 and the charged surface is subjected to the 1st image exposure by image exposure 4 by each color. The resulting electrostatic image is subjected to the 1st development by a developing device using a developer of the color toner corresponding to the image exposure 4 among developing devices 5-8. After the surface is destaticized by the destaticizer 13, the 2nd electostatic charge is executed again by the charger 2 at the 2nd turn and the charged surface is subjected to the 2nd image exposure by the image exposure 4 of the color different from the color of the first exposure. The image is developed for the second time by the developing device of the corresponding color toner. The 3rd and 4th formation and development of the electrostatic image are thereafter repeated in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image recording method such as copying a color image, and in particular to a method for forming and developing an electrostatic image on an image forming member having a photoconductive photoreceptor surface layer. The present invention relates to a color image recording method in which toner images are repeatedly superimposed 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.

The method described in JP-A-56-144452 is
After the surface of the image forming body is charged by a charger, an electrostatic image is formed on the charged surface by a first exposure means, and developed by a first developer, and then a second image is formed on the same charged surface. An electrostatic image is formed by an exposure means, the image is developed by a second developing device, an electrostatic image is further formed on the same charged surface by a third exposing device, and the image is developed by a third developing device. This method forms a color image on an image forming body by using a separate exposure means for each repeated electrostatic image formation, which increases the size of the recording device and increases the cost. The installation position of each exposure means is also related to the synchronization of the exposure of the means to the image forming body, and there are problems in that synchronization control is troublesome and color shift is likely to occur. Further, each development in this method is performed by a forced development method in which toner charged to the same polarity is attached to an electrostatic image in which the potential of the exposed portion is lower than the potential of the background portion.

In this forced development method, a toner that is charged to the same polarity as that of the first image forming member is used as a developer so that the toner does not adhere to the background area. Therefore, in the reversal development method, the toner is repelled by the background potential and fogging is less likely to occur, but at the same time, the toner also adheres to the electrostatic image, making it difficult to obtain a sufficient developed density. And, JP-A-56-
The method described in Japanese Patent No. 144452 is such that the second and subsequent development by the reversal development method is carried out under non-contact jumping development conditions, in which the developer/agent layer formed in the developing device is not brought into contact with the surface of the image forming body. According to K,
Unless a strong bias voltage is applied to the developing device to force the toner to strongly adhere to the electrostatic image, it will be difficult to obtain a sufficient developed density, and the toner will easily become smeared due to scattering, and the developing device will If a strong bias voltage is applied, the bias voltage may leak to the image forming body, toner of another color may start to adhere to the previously developed toner image, or toner may adhere to the background area. There is a problem.

JP-A-58-116553 and JP-A No. 58-1165
The method described in Japanese Patent Application Laid-open No. 56-144452 is substantially the same as that in Japanese Patent Application Laid-open No. 56-144452 in that the electrostatic image formation and development are performed using different devices each time the recording device is used. It also has problems in that it is large in size and expensive, and it is difficult to control the exposure synchronization of each exposure means, which tends to cause color misregistration. However, in the method described in JP-A-58-116554, each development by the reversal development method is performed under contact development conditions in which a developer layer formed in a developing device rubs the surface of the image forming body. The problem of the toner being easily scattered due to obtaining a sufficient development density in the reversal development method is thereby alleviated, and the method described in JP-A-58-116553 The method further includes the step of recharging the surface of the image forming body before exposure using a charger provided in front of each photoreflection means in the formation of electrostatic images from the 1st to the 2nd time. This method differs from the method described in JP-A-56-144452 in that it is prevented that toner of a different color will adhere to areas to which toner has adhered in the previous development in the subsequent development. However, in these methods, since the second and subsequent developments are also performed under contact development conditions, in the subsequent development, the toner adhered in the previous development may be displaced, and the toner in the subsequent development device may be There is a big problem that it can easily get mixed in with other substances.

[Purpose of the invention]

The present invention has been made in order to solve the problems in the conventional color image recording method as described above, and the first object of the present invention is to avoid using the same apparatus for repeatedly forming electrostatic images. The second objective is to provide a color image recording method that allows the recording device to be made compact and low-cost, and that allows for easy and accurate synchronization control of image exposure. Of course, it is easy to control, and when using the normal development method in which oppositely charged toner is attached to the electrostatic image,
The object of the present invention is to provide a color image recording method that can obtain sufficient developed density under non-contact jumping development conditions even when using the forced development method, and can also prevent fogging and mixed adhesion of different color toners.

[Structure of the invention]

The present invention provides a color image recording method in which formation of an electrostatic image on an image forming body having a photoconductive photoreceptor surface layer and development are repeated to superimpose toner images on the image forming body. A color image recording method Kh characterized in that the color image recording method is repeated by the same apparatus.
Furthermore, by using a two-component developer containing a mixture of toner and an insulating carrier in the developing device, the second object has also 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 schematic diagram of a laser beam scanner for image exposure, and FIG. 3 is a partial sectional view of an example of a developing device. , 4 through 7 are flowcharts for implementing the method of the present invention.

In the recording apparatus shown in FIG. 1, reference numeral 1 denotes a drum-shaped image forming body having a photoconductive photoreceptor surface layer made 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 1; 3 is an exposure lamp that uniformly exposes the surface of the image forming body 10 with weak light;
4 is image exposure for each color of a color image, and 5 to 8 are yellow and magenta.

Developing devices 9 and 10 each using toner of different colors such as cyan and black as developers transfer a color image formed by superimposing a plurality of color toner images on the image forming member 1 to the recording member P. 11 is a transfer device, 12 is a fixing device for fixing the toner image transferred to the recording medium P, and 13 is a static elimination lamp, which are provided as necessary to facilitate transfer to the recording medium P. A static eliminator 14 comprising one or a combination of a static eliminator and a corona discharger, and the static eliminator 14 contacts the surface of the image forming body 1 after the color image has been transferred to remove residual toner on the surface, and performs the first development. The cleaning device has a cleaning blade or a fur brush that separates from the surface of the image forming body 10 by the time the surface on which the cleaning has been performed reaches the surface of the image forming body 10.

For this reason, the charger 2 is equipped with the one shown in the figure, which can provide a stable charge with less influence from the previous charge, especially when charging the surface of the image forming body 1 which is already charged. It is preferable to use a scorotron corona discharger such as In addition, in a recording device that uses a drum-shaped image forming body 1 like this recording device, the image exposure 4 is a slit exposure as in a normal monochrome electrophotographic close-up machine, and is divided into P waves for each color using a filter. However, in order to record clear color images, it is preferable to use a laser beam scanner as shown in FIG.

In the laser beam scanner shown in FIG. 2, a laser beam emitted from a laser 21 such as a He-Ne laser is converted into 0N10FF by an acousto-optic transformer 22, and then deflected by a mirror scanner 23 consisting of an octahedral rotating polygon mirror. The surface of the image forming body 1 is scanned at a constant speed through the imaging f-theta lens 24 to form an image exposure 4. In addition, 25.
26 is a mirror, and 27 is a lens for enlarging the diameter of the beam incident on the imaging f-〇 lens 24 in order to reduce the diameter of the beam on the image forming body 1. If a laser beam scanner as shown in FIG. 2 is used to form the image exposure 4, electrostatic images for different colors can be easily formed with shifts as described later, and therefore clear color images can be recorded. I can do it. However, the image exposure 4 is not limited to the slit exposure described above or the dot m using a laser beam.
It is not limited to light, and may be obtained using, for example, an LED, CRT, liquid crystal, or optical fiber transmission body. In a recording apparatus in which the image forming body can take a flat state such as a belt shape, the image exposure can also be flash exposure.

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

In FIG. 3, 31 is a developing sleeve made of a non-magnetic material such as aluminum or stainless steel, 32 is a magnet body provided inside the developing sleeve 31 and has a plurality of magnetic poles in the circumferential direction, and 33 is a magnet body formed on the developing sleeve 31. A layer thickness regulating blade 34 regulates the thickness of the developer layer formed, a scraper blade 34 removes the developed developer layer from above the developing sleeve 31, and a stirring rotation 35 stirs the developer in the developer reservoir 36. 37 is a toner hopper; 38 is a toner replenishing roller that has a recess on its surface into which toner enters and replenishes toner from the toner hopper 37 to the developer reservoir 36; 39 is a toner supply roller that is connected to the developing sleeve 31 via a protective resistor 40; This is a power source for applying a bias voltage including an oscillating voltage component in some cases and forming an electric field for controlling the movement of toner between the developing sleeve 31 and the image forming body 1. The figure shows the developing sleeve 31 and the magnet body 32. indicates that they rotate in the directions of the arrows, but even if the developing sleeve 31 is fixed, the magnet body 32 is fixed, or the developing sleeve 31 and the magnet body 32 rotate in the same direction. It may be something like that. When the magnet body 32 is fixed, usually, 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, there is a strongly magnetized magnetic body, and a magnet with the same or different polarity is attached thereto. Two magnetic poles may be placed close to each other.

In such a developing device, the magnetic pole of the magnet body 32 is usually 500 to 500.
It is magnetized to a magnetic flux density of 1500 Gauss, and the developer in the developer reservoir 936 is attracted to the surface of the developing sleeve 31 by the magnetic force, and the attracted developer is transferred to the layer thickness regulating blade 3.
3 to form a developer layer, and the developer layer moves in the same direction or in the opposite direction (the same direction in the figure) to the direction of the rotation arrow of the image forming body 1, and forms a developer layer on the surface of the developing sleeve 31. develops the electrostatic image on the image forming body 1 in a developing area facing the surface of the image forming body 1, and the residue is transferred to the scraper blade 3.
4, the developer sleeve 31 is removed from the surface of the developer sleeve 31 and returned to the developer reservoir 36. The development is repeated to superimpose the color toner images, and at least for the second and subsequent development, the toner attached to the image forming body 1 in the previous development is shifted and removed in the subsequent development. It is preferable to use non-contact jumping development conditions to avoid such problems. FIG. 3 shows a state in which development is performed under non-contact jumping development conditions.

Furthermore, the developing units 5 to 8 are equipped with non-magnetic toner, which does not require the inclusion of black or brown magnetic material in the toner and can provide toner with a clear color, and can easily control the charging of the toner. It is preferred to use so-called two-component developers, which consist of a mixture with a magnetic carrier. In particular, the magnetic carrier is styrene resin.

Vinyl resin, ethyl resin, rosin modified resin.

Acrylic resin, polyamide resin, epoxy resin.

Resin such as polyester resin containing dispersed particles of ferromagnetic or paramagnetic material such as triiron tetroxide, γ-ferric oxide, chromium dioxide, manganese oxide, ferrite, manganese-copper alloy, etc. Alternatively, it is preferable to use an insulating carrier having a resistivity of 10 8 Ω or more, preferably 10 13 Ω or more, which is made of magnetic particles whose surfaces are coated with the above-mentioned resin. If this resistivity is low,
When a bias voltage is applied to the developing sleeve 31, a problem arises in that charges are injected into the carrier particles and the carrier particles tend to adhere to the surface of the image forming member 1, or that a sufficient bias voltage is not applied. In particular, when the carrier adheres to the image forming body 1, the tone of the color image is not adversely affected.

The resistivity is determined by placing particles in a container with a cross-sectional area of 0.50 cJn2, tapping them, applying a load of I K97 cm' on the packed particles, and applying an electric field of 1000 V/cm between the load and the bottom electrode. This value is obtained by reading the current value when applying a voltage that produces .

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. Particle size is 5μm or more and 40μm
m or less, and if necessary, a fluidizing agent such as hydrophobic silica or the like may be appropriately added as an additive.

The toner preferably has an average particle size of 1 to 20 μm, which is made by adding each m pigment to the resin and, if necessary, a charge control agent.
And the average charged shellfish is 3~300μC/2, especially 10~
100μc/r is preferable.

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

When a developer consisting of a mixture of an insulating carrier and toner as described above is used, the bias voltage applied to the developing strip IJ-pull 31 shown in FIG. Settings can be easily made without fear of causing leaks so that no turn 9 occurs. In addition, in order to more effectively control the development movement of the toner by applying the Iasumi pressure, the toner may contain a magnetic material such as that used in magnetic carriers to the extent that color clarity is not impaired. You may let them.

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.

55-18656 to 18659, 56-1444
52 and 58-116553 to 116554 may be used. More preferably, Japanese Patent Application Nos. 58-57446 and 58-96900 to 96903 previously filed by the applicant of the present application.
It is preferable to use non-contact jumping development conditions using a two-component developer as described in the specifications of No. 58-97973.

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, all of FIGS. 4 to 7 show the stage up to the stage where the development shown in FIG. 2 has been performed.

Figure 4 shows that an electrostatic image is formed by an electrostatic image forming method in which the exposed area is the background area and the non-exposed area is an electrostatic image. 3 shows an embodiment of the invention carried out by adhesion. According to the recording apparatus shown in FIG. 1, this is because the static electricity is removed by the static eliminator 13 and cleaned by the cleaning device 4, and the surface of the image forming body 1 in the initial state where the potential is 0 is exposed to the surface of the image forming body 1 during the first rotation. The charged surface is uniformly charged for the first time by the charger 2, and the charged surface is subjected to a second image exposure by color-specific image exposure 4 so that the potential other than the electrostatic image area becomes approximately 0. The electrostatic image whose potential is approximately equal to the potential of the first charging is developed for the first time by a developing device using a developer of a color toner corresponding to image exposure 4 among the developing devices 5 to 8, Since the potential of the electrostatic image, which has decreased due to the attachment of the charged toner T, is still higher than the background potential, the charge is uniformly removed by the static eliminator 13 (only the static eliminator lamp may be used) and the image is formed again. The surface potential of the body 1 is set to 0, and in the second rotation, a second charge is uniformly applied again by the charger 2, and the charged surface is subjected to image exposure 4 of a color different from the previous one, so that areas other than the electrostatic image area are also exposed. A second image exposure is performed in which the potential is approximately O, and the obtained electrostatic image is developed a second time with toner T' using a separate developer using a developer of a corresponding color toner, and the same is true. To, the third time.

The fourth electrostatic image formation and development are repeated until the fourth development is performed and a color image in which color toner images are superimposed is passed through the pre-transfer charger 9. and the pre-transfer exposure lamp lO, and then the transfer device 1
1 transfers a color image to a recording medium P that is fed in synchronization with the rotation of the image forming body 1, and the transferred color image is fixed on the recording medium P by a fixing device 12. The surface of is neutralized by static eliminator BK,
In this embodiment of the present invention, one cycle of shicolor image recording is completed by returning to the initial state by being cleaned by the cleaning device 14. That is, charging for electrostatic image formation each time is performed by the charger 2, and image exposure is also performed by the same slit exposure device equipped with filter switching means or the same exposure device created by the laser beam scanner shown in FIG. 2, for example. Because the process is performed by be exposed. Note that the charge removal by the charge remover 13 between the previous development and the next charge can be omitted.

In the embodiment shown in FIG. 4, development is carried out by a visual method in which an electrostatic image is imaged with toner charged to opposite polarities, so it is easy to increase the development density of each color, and therefore it is easy to Capable of recording clear color images. Note that, in order to avoid color mixing, it is preferable to set the DC bias during development to higher values in later stages. Correspondingly, the charging potential may also be set higher in sequence.

Figures 5 to 7 show that an #electronic image is formed by an electrostatic image forming method in which the image exposure area becomes an electrostatic image with a lower potential than the background area, and development causes the electrostatic image to have the same polarity as the background area potential. 7 shows an embodiment of the present invention in which charging is caused by adhesion of toner.

In the embodiment shown in FIG. 5 using the recording apparatus shown in FIG. 1, the surface of the image forming body l in the same initial state as shown in FIG. second to
A first image exposure is performed in which the potential of the electrostatic image area becomes approximately 0 by projecting image exposure 4 for each color using the laser beam scanning K shown in the figure. A developer with a color toner corresponding to image exposure 4 (however, in this case, a developer whose toner is charged to the same polarity as the charge of the image forming member 1, which is different from the example shown in FIG. 4) is used. The image is developed for the first time using a developing device, and from the second rotation, an image exposure 4 of a different color is projected at a position shifted from the projection position of the previous development exposure 4 using the same laser beam scanner without using the charger 2. Then, a second image exposure is performed, and the electrostatic image obtained thereby with a potential of approximately O is developed by another developer using a developer of a corresponding color toner, and then a third image is exposed in the same manner. ,
Repeat the fourth electrostatic image formation and development, and then
This completes one cycle of color image recording in the same manner as described with reference to the figure. Note that in this example, the potential is approximately O
The electrostatic image was formed later because even if the toner T charged to the same polarity as that of the image forming body 1 is attached after development, the potential does not become approximately equal to the background potential as shown in the figure. During development in which toners T' of different colors are attached to an electrostatic image, toners T' are accumulated on the electrostatic image area to which toners to T have first adhered, even though no exposure, that is, no writing has been performed. It often sticks to the surface. However, since a laser beam scanner is used to form the image exposure 4, it is extremely easy to shift the projection position of the image exposure 4 each time, and charging can be done only once. Although it is easy for different electrostatic images to overlap, it is possible to prevent the occurrence of overlapping by setting the DC bias lower in each development process, thereby obtaining a color image with excellent clarity. I can do it.

In the example of FIG. 6, it is not possible to actively form an electrostatic image in the position where the electrostatic image was previously formed in the example of FIG. Since there is a high possibility that even a small amount of toner of a different color will adhere to the image area during subsequent development, this is an example in which these points have been improved. That is, the sixth
In the example shown in the figure, the process from the initial stage to the first development 1 is the same as the first development shown in FIG. is omitted, and in the second rotation, the charger 2 uniformly charges the surface for a second time, performs a second image exposure on the charged surface, performs a second development, and then similarly performs a third development. This example differs from the example shown in FIG. 5 in that the electrostatic image formation and development are repeated twice. In this way, in the example of FIG. 6 in which the surface of the image forming body l is uniformly charged again after the previous development to perform the subsequent electrostatic image formation and development, it is different from that in the example of FIG. 4. Similarly, it is possible to form an electrostatic image overlapping the position where the previous electrostatic image was formed, and if the subsequent electrostatic image formation position is shifted from the previous one, it is possible to overlap the position where the previous electrostatic image was formed. The effect is that there is almost no possibility that later toner of a different color will adhere to the image position.

The example shown in FIG. 7 is an example in which a subsequent different color toner is particularly prevented from adhering to an image position to which a previous toner has adhered. In this example, the steps up to the first development are the same as those shown in FIGS. 5 and 6, but after the first development, the pre-transfer exposure lamp 10 or the static elimination wrap of the static eliminator 12 is used The surface of the image forming body 1 is first uniformly exposed to light and then charged a second time with the charger 2, or the surface of the image forming body 1 is first uniformly charged with the second time with the charger 2, and then the surface is uniformly and weakly charged with the exposure lamp 3. By exposing it to light,
Then, a second image exposure and a second development are performed, and the fourth tlI electric image formation and development are repeated 83 times in the same manner. In this case, if the toner is uniformly exposed first after development, the developed area to which the toner has adhered remains at a high potential without being neutralized, and the other area remains at approximately O potential.
By performing double charging, the surface of the image forming member 10 can be charged by making the potential of the part to which the toner is attached slightly higher than that of the other part where an electrostatic image is formed. , after development, the image forming body 1 is first charged a second time.
Even if the surface of the image forming member 1 is uniformly charged and subjected to uniform weak exposure, the charged state of the surface of the image forming member 1 will be the same as when uniform exposure is performed first.

Therefore, when developing the electrostatic image formed by shifting the next position, the potential of the area where the previous toner was attached is high, so it is effectively prevented that different colored toners will adhere there. .

In any of the above examples, it is preferable to use a developer made of a mixture of toner and an insulating carrier in the developing devices 5 to 8, and to perform the development under non-contact jumping development conditions. As mentioned above, this prevents the mixing of toners of one color and the like, and also makes it easy to apply an appropriate bias voltage for toner control to the developing sleeve 31 of the developing device. Even when an electrostatic image forming method or a developing method is used as in the examples shown in FIGS. 5 to 7, in which an image exposure device such as the one shown in FIG. I can do it.

Next, the embodiments shown in FIGS. 4 to 7 will be specifically described as Examples 1 to 3, respectively.

Example 1 (Example shown in FIG. 4) A recording apparatus as shown in FIG. 1 was used. However, the exposure lamp 3 was not used, the image forming body 1 had an OdS photoreceptor surface layer, and its eyebrow speed was 18 olII/se.

And so. The surface of this image forming body 1 is charged to 6-500 V by a charger 2 using a scorotron corona discharger,
Slit exposure was performed on the charged surface through a blue filter. As a result, an electrostatic image was formed on the image forming body 1 in which the background potential of the exposed area was -50V and the potential of the non-exposed area was 1500V. This electrostatic image was first developed using a developing device 5 as shown in FIG.

The developing device 5 contains sowt% magnetite dispersed in the resin, with an average particle size of 20 μm and a magnetization of 30 emμ/2.
A carrier having a resistivity of 1014 Ω or more, a styrene-acrylic resin containing 10 parts by weight of a benzene derivative as a yellow pigment, and other charge control agents, with an average particle size of 10 μm.
A developer consisting of non-magnetic toner was used under conditions such that the ratio of toner to carrier was 25 wt %. In addition, the outer diameter of the developing sleeve 31 is 30mm, and the number of rotations is 1100mm.
rp, the magnetic flux density of the N and S magnetic poles of the magnet body 32 is 1000 gauss, the rotation speed is 101000 rp, the thickness of the developer layer in the developing area is 0.7mm, the gap between the developing sleeve 31 and the image forming body 1 is 0.8M A non-contact jumping development condition was adopted in which a superimposed voltage of a DC voltage of -100 V and an AC voltage of 3 kHz, 1000 V was applied to the developing sleeve 31.

TwJ, which was developing the electrostatic image with the developing device 5, kept the other developing devices 6 to 8, also shown in FIG. 3, in a non-developing state. This can be done by separating the developing sleeve 31 from the electrode #39 and putting it in the 70-ting state, or /'i
, by grounding, or by actively applying to the developing sleeve 31 a DC bias voltage having the same polarity as the charging of the image forming body 1 and the opposite polarity to the charging of the toner, among others, applying a DC bias voltage. It is preferable. Since the developing units 6 to 8 are also designed to perform development under the non-contact jumping development conditions like the developing unit 5, the developer layer on the developing sleeve 31 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 polytanodust phosphoric acid as a magenta pigment instead of a yellow pigment. A developer was used in which the toner was changed to a toner containing copper phthalocyanine as a cyan pigment, and a developer in which the toner was changed to a toner containing carbon black as a black pigment was used in the developing device 8. Of course, color toners based on other pigments or dyes can be used, and the order of the colors to be developed and the order of the developing devices can also be appropriately selected.

The surface of the image forming body 1 that had been subjected to the first development was re-charged to -600V by acting on the static eliminator 13 and charger 2 (the static eliminator did not need to be operated). A second image exposure is performed by slit exposure with a green filter on the surface, and then the developing sleeve 31 is exposed with a
A second development of the magenta toner was performed using the developing unit 6 under non-contact jumping development conditions in which a superimposed voltage of a DC voltage of V and an AC voltage of 3 kHz +1000 V was applied. Similarly, electrification, slit exposure through a red filter, third development of cyan toner by developer 7, and fourth development of black toner by slit M light, which does not pass through electrification and filter, and developer 8, are repeated. Ta. In the second and subsequent development, the amplitude 2 of the DC bias component and AC component of the voltage applied to the developing sleeve 31 is adjusted appropriately according to changes in the surface potential of the image forming weight, development characteristics, and color reproducibility. Changed the selection time etc. of frequency 1 hour selection conversion.

In particular, gradually increasing the charging potential and gradually increasing the DC bias has the effect of preventing color mixing of toners.

When the fourth development is performed and a four-color image is formed on the image forming body 1, the image is easily transferred by the pre-transfer charger 9 and the pre-transfer exposure lamp 10, and then transferred to the recording body by the transfer device 11. The image was transferred to 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 static eliminator 13, and 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 process of color image recording is completely completed at the time of passing through the device 13.

The color image recorded in the above manner was clear with sufficient density for each color, but some color mixing of toners was observed in areas where the toners of each color were closely adhered to each other.

Example 2 (Example shown in FIG. 5) A recording apparatus as shown in FIG. 1 was used. However, the exposure lamp 3 was not used, the image forming body 1 had an SE photoreceptor surface layer, and the peripheral speed was 180 mm/sec.

The surface of the image forming body 1 is charged to +500 VK by a charger 2 using a scorotron corona discharger. The first image exposure was carried out at a density of 16 dots/meter using a laser beam scanner shown in FIG. 2 using a K He --Ne laser on the charged surface. As a result, the image forming body 1 has a background potential of +
An electrostatic image with a potential of +50 V at the exposed area was formed with respect to 500 cm. This electrostatic image is transferred to a developing device 5 as shown in FIG.
The image was developed for the first time.

The developing conditions for the developing device 5 are as follows: the average particle size of the developer carrier is 301 tm, the ratio of toner to carrier is 20 wt %, and the developing sleeve 31 has a DC voltage of +400 V and an AC voltage of 1.5 kHz, 1000 V. The procedure was the same as in Example 1 except that a superimposed voltage was applied. Also,
The conditions of other developing units 6 to 8 are the same as in Example 1 except for the bias voltage.
The same as However, in this case, the bias voltage that maintains the developing device that does not participate in development in a non-developing state has a polarity opposite to that of toner charging, and also has a polarity opposite to that of image forming body 1.

A pre-transfer charger 9, a pre-transfer exposure lamp 10. Static eliminator 13. Without operating the cleaning device 4 and charger 2, a second image exposure is performed again using the same laser beam scanner with the density unchanged and the dot position shifted, and then a second development of magenta toner is performed using the developer 6. went. Similarly, the third development of the yellow toner by the developer 7 and the fourth development of the black toner by the developer 8 were repeated. In the second development and subsequent developments, the amplitude of the DC bias component and AC component of the voltage applied to the developing sleeve 31 is adjusted appropriately according to changes in the surface potential of the image forming body 1, development characteristics, and color reproducibility. I turned it around to change the selection time etc. of 1 frequency 2 time selection conversion. In this example, it is particularly effective to gradually reduce the DC bias each time to prevent color mixing of toners.

After the fourth development is performed and a four-color image is formed on the image forming body 1, the rest is transferred and fixed onto the recording medium P, and the image forming body 1 is destaticized and cleaned in the same manner as in Example 1. This completed one cycle of color image recording.

The color image recorded in the above manner was as clear as in Example 1.

Embodiment 3 (Example shown in FIG. 6) Using the same device as in Embodiment 2, the voltage applied to the developing sleeve 31 of the developing device was +400 V DC voltage and 5 V.
A superimposed voltage of AC voltages of 0.00 Hz and 250 V was used, and before each image exposure after the second image exposure, static electricity was removed by the transfer exposure lamp 10, and then the surface potential of the image forming body 1 was set by the charger 2. Color image recording was carried out under the same conditions as in Example 2, except for recharging to +500 V.

The recorded color image is better than that of Example 2.
The color mixing of the toners in the areas where the color toners adhered closely to each other was reduced, resulting in a -N clear image.

In addition, according to this embodiment, as mentioned above, the earlier image exposure position and the later image exposure position can be overlapped, and in that case, the order of developing colors depends on the sharpness of the color image. Since this will have a considerable effect, it is necessary to carefully decide the order of the colors to be developed.

Example 4 (Example shown in FIG. 7) The same apparatus as in Example 2 was used except that the exposure lamp 3 was provided, and the voltage applied to the developing sleeve 31 of the developing device was a DC voltage of +450 V and a frequency of 2 kHz, 500 V.
A superimposed voltage of an AC voltage of V is used, and before each image exposure after the second image exposure, charging is performed by a charger 2 to bring the surface potential of the image forming body 10 to +600V, and an exposure lamp 3 to lower the surface potential to +500V. A shicolor image was recorded under the same conditions as in Example 2, except that uniform weak exposure was performed.

The recorded color image was extremely clear, with no color mixing of the toners even in areas where the toners of each color closely adhered to each other.

In this embodiment as well, as in the third embodiment, the previous image exposure position and the subsequent image exposure position can be overlapped.

〔Effect of the invention〕

According to the present invention, the same device is used for repeated electrostatic image formation, the recording device can be made compact and low cost, and the synchronization control of each image exposure can be easily and accurately performed. It is also possible to perform each development using a development method in which a toner charged to the opposite polarity is attached to the electrostatic image, which is relatively easy to control the development density, or by using a laser beam scanner as the image exposure device. This can be done by a developing method in which a toner charged with the same polarity is attached to the electrostatic image that is formed.In addition, in any of the developing methods, development is performed under non-contact jumping development conditions to ensure that the developed density is sufficient. It is possible to obtain an excellent effect of being able to record a color image with excellent clarity.

As mentioned above, the present invention is not limited to those in which the image forming body uses a drum-shaped recording device, and is not limited to those in which a color image is transferred to the recording medium. do not have. That is, the present invention can also be applied to an image forming body mounted on a substrate such as electrofax paper, on which a color image is fixed without being transferred. In this case, a pre-transfer charger, a pre-transfer exposure lamp, a transfer device, and even a cleaning device are not required. Of course, the pre-transfer charger, pre-transfer exposure lamp or static eliminator can be omitted even when transferring, and the transfer can be either direct pressure transfer or transfer via an intermediate transfer body, and the fixing can be done by heat roller fixing. Of course, it is not limited to.

[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. , 4 through 7 are flowcharts for implementing the method of the present invention. DESCRIPTION OF SYMBOLS 1... Image forming body, 2... Charger, 3... Exposure lamp, 4... Image exposure, 5-8... Developing device, 10
... Pre-transfer exposure lamp, 11... Transfer device, 12...
- Fixing device, 13... Static eliminator, 14 - Cleaning device, P... Recording body, 21... Laser, 22...
・Acousto-optic modulator, 23...Mirror scanner, 24・
...Image forming f-theta lens, 25, 26...Mirror, 27...Lens, 31...
- Developing sleeve, 32... Magnet, 33... Layer thickness regulating blade, 34... Scraper blade, 35... Stirring rotor, 36... Developer reservoir, 37
・Toner hopper, 38 toner supply roller, 39...
・Power supply, 40...Protection resistor. Patent Applicant Konishi Roku Photo Industry Co., Ltd., −°... 1 Figure 2 Figure 3 Figure J Figure 4 Figure 5 Procedural Sleeve Book October 2i, 1981 Kazuo Wakasugi, Commissioner of the Patent Office, 1. Indication of the case 1984 Patent Application No. 18438133, Person making the amendment Relationship to the case Patent applicant address 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name (
Name) (127) Konishiroku Photo Industry Co., Ltd. 4, Agent
Person 160 Telephone: 556-60906 Number of inventions increased by amendment None 7. Subject of amendment (1) "Image exposed portion" on page 15, line 16 of the specification is changed to "
Correct it to exposure part PHJ. (2) "Non-exposed area" on page 15, lines 16-17 of the same
Correct it to non-exposed area DAJ. (5) "Image exposure section" on page 18, line 12 of the same page is corrected to "exposure section PHJ." (4) "Development exposure" on page 19, line 9 of the same page is changed to "image exposure"
I am corrected. (5) Change “Exposed area” in the third line of page 24 to “Exposed area PH”.
J, and “non-exposed area” is corrected as “non-exposed area DAJ.” (6) “Exposed area” on page 28, line 10 of the same page is changed to [exposed area P
Correct with HJ. (7) Figures 4 to 7 of the drawings will be corrected as shown in the attached sheet. Figure 4 511 No. 6 Oral Procedures Amendment Date January 7, 1980 Manabu Shiga, Commissioner of the Patent Office 1.41 indications 1984 Patent Application No. 184381 2° Invention 0 Title Color image record Method 3: Relationship with the case of the person making the amendment Patent applicant address: 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name (
Name) (127) Konishiroku Photo Industry Co., Ltd. 6. Number of inventions increased by amendment 07. Scope of claims and detailed description of invention of specification subject to amendment
No. 4 (Attachment) 1. The scope of claims is amended as follows. [(1) In a color image recording method in which toner images are superimposed on an image forming body having a photoconductive photosensitive layer by repeatedly forming and developing an electrostatic image on the image forming body, the formation of the electrostatic images is the same. A color image recording method characterized in that the color image recording method is repeated by a device. (2) The color image recording method according to claim 1, wherein a two-component developer containing a mixture of toner and an insulating carrier is used for the development. (5) The color image recording method according to claim 1 or 2, wherein the second and subsequent development steps are performed without bringing the developer layer formed in the developing device into contact with the surface of the image forming member. . (4) The color image recording method according to any one of claims 1 to 6, wherein the image forming member is cleaned by a cleaning device after transferring the color image in which the toner images are superimposed. ” 2. "Photoreceptor surface layer" on page 2, line 5 and page 6, line 11 of the specification is corrected to "sunlight layer". 3 In the same page, page 13, line 14, "1 load" is corrected to "an electrode that also serves as a load body." 4. Correct "40 μm" in the first line of page 14 to "150 μm". 5. Change "Static eliminator B" on page 17, line 9 of the same page to "Static eliminator 13".
” is corrected. that's all

Claims (1)

[Scope of Claims] (1) In a color image recording method in which toner images are superimposed on an image forming member having a photoconductive photoreceptor surface layer by repeatedly forming and developing an electrostatic image on the image forming member, the electrostatic A color image recording method characterized in that formation of an electric image is repeated by the same device. (2) The color image recording method according to claim 1, wherein a two-component developer containing a mixture of toner and an insulating carrier is used for the development. (5) The color image recording method according to claim 1 or 2, wherein the second and subsequent development steps are performed without bringing the developer layer formed in the developing device into contact with the surface of the image forming member. . (4) The color image recording method according to any one of claims 1 to 5, wherein the image forming member is cleaned by a cleaning device after transferring the color image in which the toner images are superimposed.