JPS60195560A - Image forming method - Google Patents

Abstract

PURPOSE:To transfer collectively a toner image of three colors or more, to form a picture of multicolor having no resist shift at a high speed, and also to obtain a full color picture having good half tone reproducibility in case when a color signal is brought to operation processing, by repeating each process of destaticization, a digital charge pattern formation by an ionic current and development to a solid-state dielectric surface, in the course of one rotation of the solid- state dielectric. CONSTITUTION:An endless belt provided with a solid-state dielectric layer 22 on a conductive base body is set to rollers 20, 21 with the dielectric layer 22 outside and turned in the direction as indicated with an arrow. First of all, the surface of the dielectric layer 22 is destaticized to about ''0''V by an AC electrifier 23. Subsequently, an electric signal corresponding to a display picture is sent to a digital electrifier 24, a digital charge pattern of a picture is formed on a photosensitive drum 22, and this charge pattern is converted to a developed image by a developing device 27. This solid-state dielectric or its surface is made white in order to maximize the contrast of a toner image and the solid- state dielectric being a background. In this way, an electrophotograpy display of full colors or multicolors is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming method, and more particularly to an image forming method for obtaining images based on different latent images.

Conventionally, full-color hard copy images have been composed of three primary colors: yellow, magenta, and cyan, and color reproduction has been performed by so-called subtractive color mixing. FIG. 7 shows a color m-laser beam printer that has been proposed so far.

The laser light La modulated by the image signal is converted into a laser light having a predetermined beam diameter by the beam expander 41 and is incident on the polyhedral reflecting mirror 42 . Polyhedral reflector 4
2 has a plurality of reflecting mirrors and is rotated at a predetermined speed by a constant speed rotation motor 43, so that the incident laser beam La is scanned substantially horizontally.

The light is then imaged as a spot light onto the photosensitive drum 5I through the slit of the secondary charger 54 by the imaging lens 44 having f-θ characteristics. Note that a part of the output laser light from the imaging lens 44 is reflected by a reflecting mirror 45 and transmitted to a beam detector 46.
The timing of the modulation operation of the semiconductor laser 40 is controlled because predetermined optical information is detected on the photoreceptor drum 51 by its output signal.

The photosensitive drum 51 includes, for example, a CdS photosensitive member 41 having a three-layer structure including a conductive support, a photoconductive layer, and an insulating layer, and is rotatably supported. The photosensitive drum 51 is cleaned in advance by a cleaning unit 52, and then the influence of a previously formed latent image is removed by an AC charger (not shown). Further, as the surface rotates in the direction of the arrow shown in the figure, the surface is uniformly positively charged by the primary charger 53, then negatively charged by the secondary charger 54, scanned by a laser beam, and further exposed to the lamp. 55, an electrostatic latent image is formed by uniform exposure.

This latent image is developed by the corresponding color developing device among the developing devices 56, 57, and 58 having yellow, magenta, and cyan developers, respectively. Of the above, the polarity of charging is merely an example, and the polarity differs depending on the conductivity type of the photoreceptor.

The transfer material 60 stored in the cassette 59 is transferred to the photosensitive drum 51.
The tip of the transfer material 60 is held by the gripper 62a of the transfer drum 62, which has the same diameter as the photosensitive drum 51, by the paper feed roller 61 in synchronization with the rotation of the photosensitive drum 51. It is wrapped around the surface of the polyester mesh screen 62b. Transfer charger 6
2c transfers the developed image on the photosensitive drum 51 to a transfer material 60.
At the same time, the back surface of the mesh screen 62b is charged, thereby causing the transfer material to be electrostatically attracted to the surface thereof.

After the developed image on the photosensitive drum 51 is multiple-transferred to the transfer material 60 on the transfer drum 62 with three-color alignment, the gripper 62a is released and the separation claw 62d is operated to remove the transfer material 60. To separate. The transfer material 60 is guided by a conveyor belt 63 to a heating roller fixing device 64, where the transferred image is heated and fixed, and then the transfer material 60 is discharged onto a paper discharge tray 65. In this way, a full-color image is formed on the transfer material 60, and document information corresponding to the color signals input to the color laser printer is faithfully reproduced.

In this way, in conventional color laser printers, in order to form a full color image, toner images of each of the three primary colors are superimposed and fixed on transfer paper by repeating the above five steps of charging, exposure, development, transfer, and cleaning. let

Therefore, there are problems in that the time required for one copy is long and the apparatus becomes complicated.

The present invention has been made in view of these points, and has the structure described in the claims.

In other words, by controlling the ion flow generated by the dielectric breakdown of the air according to the WIJ1 color signal, a digital charge (turn?lW) image of the ions is formed on the latent image carrier, and this is combined with the color signal of the first color. Development is carried out using a developer having a complementary color relationship.As a result, a toner image of the first color is formed on the latent image carrier.

Next, the second color toner image is charged to a uniform potential, and then
Similar to the formation of a latent image of the first color, a second
A digital charge pattern latent image of a color is formed on a first color toner image, and then developed with a toner having a complementary color to the second color, thereby forming a second color toner image.

A third color toner image is also formed on the second color toner image by a similar process. As a result, toner images of three or more colors can be transferred at once, and a multicolor image without registration deviation can be formed at high speed. Further, when the color signals are subjected to arithmetic processing using a known dither method or the like, a full-color image with good halftone reproducibility can be obtained.

Hereinafter, details of the present invention will be explained using specific examples with reference to the drawings.

FIG. 1 explains one embodiment of the process steps based on the present invention, and (1) to (2) are schematic diagrams showing the surface potential Vs of the solid dielectric material and the development state of the toner image in each step. In the figure, a digital charge pattern is formed on a solid dielectric material by a digital charger according to a color signal of a first color. At this time, the surface potential of the pattern Vs
However, it is impossible to measure each dot of the pattern due to the resolution problem of the electrometer probe. Therefore, it is measured by an electrometer and is the average value of the charge pattern of the latent image. If the charge of all the tondo patterns is applied to an area wider than the resolution of the probe, the potential will be blurred.
The voltage becomes 200V, and the area where there is no charge in the dot pattern becomes approximately OV.

II Wang Cheng The digital charge pattern formed in step I is developed with toner having a complementary color to the color signal of the first color. At this time, for example, if the color signal of the first color is blue, development is performed using a developer of yellow Y, which is its complementary color. At this time, the yellow toner is negative (
-) A developing sleeve is coated with a polar one-component insulating toner, and development is performed by a non-contact developing method.

During this first development, alternating current and direct current bias voltages are applied to the developing sleeve. The alternating voltage component of the bias in this case is such that the toner in the sleeve L can form a powder cloud and transfer in response to the potential of the solid dielectric without contacting the toner on the solid 'pA body. In addition, the DC voltage should be at a potential that can prevent fogging of the pack ground. Ultrasonic waves can also be used as a powder cloud generation method.

(2) Process The surface of the solid dielectric is neutralized by normal corona charging using an AC charger, and the potential of the surface of the solid dielectric is lowered almost uniformly to O2. - The electric potential mentioned above does not necessarily have to be OV, and includes the toner image area,
The object of the present invention is satisfied if the potential is like -.

Step (2) A digital charge pattern corresponding to the color signal of the second color is applied by a digital charger onto the solid dielectric material having the toner image of the first color.

■Process Developing with a toner that has a complementary color to the color signal of the second color.At this time, 1.For example, if the color signal of the second color is green, the toner of the developer is a complementary color. It becomes magenta M. Toner polarity, bias, and other development conditions are the same as in step (2).

Step (2) As in step (2) above, static electricity is removed from the surface of the solid dielectric to lower the surface potential Vs almost uniformly.

(2) Step A digital charge pattern corresponding to the color signal of the third color is applied onto the solid dielectric material having toner images of complementary colors corresponding to the color signals of the first color and the second color on the surface thereof.

(2) Process Development is performed under the same conditions as in the above-mentioned (11) process using a toner having a complementary color to the color signal of the third color.

At this time, for example, if the color signal of the third color is red, the toner of the developer is cyan C, which is a complementary color.

FIG. 2 is an explanatory diagram of a specific example of an image forming apparatus that implements the method of the present invention. The surface of the solid dielectric drum l is neutralized to about Ov by an AC charger 3, and then a digital charge pattern corresponding to the color signal of the first color is applied by a digital charger 4 (step ■). Since the first color is related to blue, the first color obtained in this way
The colored electrostatic latent image is subjected to jumping development using the first developing device 5 containing yellow non-magnetic one-component insulating toner having negative polarity (Step II).

The distance between the developing sleeve 51 of the first developing device 5 and the solid dielectric material is approximately 300 pm, and a bias voltage is applied to the sleeve 51 by a power source (not shown).

This bias voltage has an AC component of 2 to 3 KHz, 1
000-1500V p p, +IOV as DC component
+50V is superimposed from the voltage. As another method, the method described in Japanese Patent Publication No. 5B-118080 can also be applied.

Next, a corona discharge is performed on the surface of the solid M electric drum 1 using an AC band W device 6. 7 for the corona discharge wire of AC charger 6
An AC voltage of KV is applied. Due to this AC charging, both the developed and undeveloped areas due to yellow toner are almost zero.
Static electricity is removed until (■ process).

Next, a latent image of a digital charge pattern corresponding to the second color (that is, green) color signal is formed on the surface of the solid dielectric drum 1 by the digital charger 7 (step (2)).

Next, the latent image corresponding to the second color is developed with magenta toner by the developing device 8 (Step V). This magenta toner is a one-component non-magnetic insulating toner having negative polarity, and This is almost the same as 1 development, and since a non-contact development method is used, the latent image of the second color is developed without spilling the toner image of the first color.

Next, an AC charger 9 is applied to the surface of the solid dielectric drum 1.
By this AC charging, which performs a colossal discharge of +7 KV, the developed areas and undeveloped areas corresponding to the first color and the second color are all neutralized and become almost OV (step (■)).

Next, a digital charger 10 is placed on the surface of the solid dielectric drum l.
A latent image of a digital charge pattern corresponding to the third color (namely red) color signal is formed (step 2).

Next, this third color latent image is developed with cyan toner by the third developing device 11 under the same conditions as the first and second latent images (step (2)).

When the third development is completed, the three-color toner images of yellow, magenta, and cyan on the solid dielectric material L are as follows.

The transfer charger 12 simultaneously transfers the images onto the transfer material 13 at once.

After the transfer, the untransferred toner on the surface of the solid dielectric drum is cleaned by a blade cleaner 2 and then neutralized by an AC static eliminator 3. On the other hand, the toner on the transfer material 13 is fixed by the fixing device 14.

Note that the transfer is usually achieved by applying an electric charge having a polarity opposite to that of the toner to the back surface of the transfer paper. However, yellow, magenta, and other toners that form toner images on a solid dielectric material are charged at least once by a digital charger and an AC charger. There is a time when the polarity of the toner is reversed before the polarity of the toner is reached.Therefore, it is better to provide a pre-processing to restore the reversed polarity of the toner to the normal polarity. In the invention, yellow, magenta,
A 3-ton cyan toner image is negatively charged with the same polarity as the toner, and then a transfer charger 12 applies a positive charge with the opposite polarity to the toner from the back side of the transfer paper.

Although the above embodiment is a case of color overlapping, it is also possible to form an image using the color of the toner in the developing device without performing color overlapping.
In this case, multicolor printing is possible depending on the number of developing devices.

An example thereof is shown in FIG.

(2) Step A digital charge pattern corresponding to the first color is formed on the solid dielectric drum.

TI process The charge pattern is developed with a negative polarity toner, for example black toner B. In this case, the DC component of the developing bias is Ov.

■Process At a potential twice that of the charge pattern in the I process,
A charge pattern corresponding to 882 colors is applied to the solid dielectric material, and in step 2, the solid dielectric material is developed with a toner having negative polarity, for example, a red toner corona. In this case, since the DC component of the developing bias is set to approximately the same value as the charge pattern in the manufacturing process, color mixing of the second color toner with the first color charge pattern does not occur.

■Process A charge pattern corresponding to the third color is applied to the solid dielectric material at a potential roughly three times higher than the potential of the charge pattern in the I step, and developed with negative polarity, for example, blue toner G in the I do.

This allows you to obtain color copies of three colors: red, black, and blue.

Note that in this embodiment, there is no need to eliminate static electricity after applying the red digital charge.

FIG. 4 is a vertical sectional side view showing a schematic structure of an embodiment in which the present invention is applied to an image display device.

An endless belt consisting of a solid dielectric layer 22 provided on a conductive base is placed on rollers 20 and 21 and rotated in the direction of the arrow so that the solid dielectric layer 22 is on the front side.

First, the surface of the solid dielectric layer 22 is neutralized to about OV by the AC charger 23.

Next, an electrical signal corresponding to the display image is sent to the digital charger 24, and a digital charge pattern of the display image is formed on the photosensitive drum 22.

This digital charge pattern is converted into an m-image by a developing device 27. The bias and other developing conditions are almost the same as described in FIG. 28 is a cleaner.

This solid dielectric material or its surface is white to maximize the contrast between the toner image and the solid dielectric material as the background. The solid dielectric material is made by dispersing white pigments such as zinc oxide or titanium oxide in an organic resin selected from the group consisting of UV-curable polyamide resin, UV-curable acrylic resin, thermosetting epoxy resin, etc. can be used.

Although the figure describes a single-color electrophotographic display, it goes without saying that a full-color or multicolor electrophotographic display can be obtained by using the methods shown in FIGS. 1 and 3 described above.

The image is viewed through a transparent plate 25 and illuminated with a lamp 26.

This image display device has better resolution than, for example, a CRT display device or a liquid crystal display device;
It has the advantages that the image is easy to see and causes less eye fatigue, and if necessary, it is possible to easily obtain a hard copy by adding a mechanism for transferring the toner image formed on the belt surface to the copy paper surface.

The method for forming a digital charge pattern using an ion flow is known from Japanese Patent Application Laid-open No. 78134/1983, and the method is exemplified below.

In FIG. 5, when performing (-) charging, when a high frequency of 1 KVpp, 500 KHz cF) is applied to the drive electrode 30, ions of ■○ are generated in the vicinity of the aperture 31. At this time, the control electrode 32 is
Furthermore, when -350V is applied to the screen electrode 33,
E ions in the aperture 31 are emitted onto the solid dielectric 34 by the electric field of the control electrode 32 and screen electrode 33.

A digital charge pattern by ions is formed on the solid dielectric when the drive electrode 3o and the control electrode 32 are applied simultaneously as described above, and FIG. 6 is a schematic diagram of the printer head.

Control line electrodes 32-1 to 32-3 have photoetched holes 31 in areas opposite to etched drive line electrodes 30-1 to 30-3.
The figure is shown as a 3×3 matrix for simplicity. Control line electrode 32 and drive line electrode 30 are separated by a thin film continuous dielectric.

The drive line electrode 30 is sequentially turned on by a commutator 35 as shown in the figure as the solid dielectric rotates, and the above-mentioned high frequency is applied. Therefore, the dots in the matrix are aligned in time with the control electrodes 32 in the correct position.
Printed onto a solid dielectric by applying a control pulse 36 of 00v. Further, since a constant voltage of -350V is applied to the screen electrode 33, a digital charge pattern of O ions is formed on the solid dielectric 34.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the process of the present invention, Fig. 2 is a schematic diagram of an apparatus for carrying out the method of the present invention, Fig. 3 is a schematic diagram of a process of another embodiment, and Fig. 4 is an image representation of the present invention. FIG. 5 is an explanatory diagram of ion charging, FIG. 6 is an explanatory diagram of a digital charge pattern forming apparatus, and FIG. 7 is a perspective view of a conventional color image forming apparatus. l is solid dielectric, 3/6-9 is AC charger, 4-7-1
0 is a digital charger, 5th grade, 8th and 11th are developing devices. Figure 5Figure 3

Claims (2)

[Claims] (1) The steps of removing static electricity, forming a digital charge pattern using ion flow, and developing the digital charge pattern are repeated at least multiple times during one rotation of the solid dielectric. A color image forming method characterized by forming different developed images on a solid dielectric material by turning the material. (2) The steps of removing static electricity, forming a digital charge pattern by ion flow, and developing the digital charge pattern on the surface of the solid dielectric are repeated at least multiple times during one rotation of the solid dielectric. 2. The color image forming method according to claim 1, wherein different toner images are formed on the solid dielectric material by turning the solid dielectric material, and then the toner images are transferred all at once to a transfer material.