JPS5931969A - Two-color developing method - Google Patents

Abstract

PURPOSE:To prevent mixing of each color toner, by using a one-component type nonmagnetic developer made of a nonmagnetic toner for the first development, and a one-component type magnetic developer made of a magnetic toner for the second development, and carrying out jumping development for each development. CONSTITUTION:The first latent image to be printed with black color having positive potential with respect to an intermediate potential Vs, and the second latent image to be printed with red color having negative potential with respect to the potential Vs are formed on the surface of a photoreceptor 1. This is developed with a developing device 5 and then, with a developing device 6. The developing sleeves of the devices 5, 6 are subjected to a developing bias voltage corresponding to the potential Vs, and a negatively charged nonmagnetic black toner is used for the device 5 and a positively-charged red magnetic toner is used for the device 6. As a result on the surface of the photoreceptor, the black toner is attached to the first latent image with the device 5, and the red toner is attached to the second latent image with the device 6, and no toner is attached to the part having the intermediate potential Vs, thus forming a 2-color print on a transfer paper sheet 9.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing method in the process of recording an image using toners of two different colors.

In recent years, with the spread of computers, facsimiles, etc.
- There has been a growing demand for Zolintar's ability to display and view the evening. In order to improve usability and attract user's attention, we have made the droplets printed out by the printer to be of two colors, including not only black but also red, for example. There is a request to remove it. Conventionally, various processes have been proposed for producing such two-color toners, but these processes have the disadvantage that the two-color toners tend to mix. The cause is
The developing device used in these processes uses iron powder as a carrier and toner is placed in an approximately 1O-shaped cylinder...! - It is a so-called two-component developer that uses a two-component developer mixed with cents, especially when the second developer for developing the second color is a two-component developer. If the first color toner image formed by the first developing device is rubbed off too much, or if the carrier has deteriorated or the ratio of 1.6- in the developer has changed, use the first toner image. Toner is less likely to adhere to the photoreceptor in any of the second developing devices, and the toner image of the first color is more likely to be damaged when the second developing device rubs the photoreceptor.

An object of the present invention is to provide a new two-color development method that prevents the above-mentioned drawbacks and prevents the toners from mixing when performing first and second development using toners of two different colors. 1 that l1fy1. U. The first development 1 is a jumping development using a one-component non-magnetic developer made of non-magnetic toner, and the second development is jumping development using a one-component magnetic developer made of a magnetic toner. .

Examples of the present invention will be described below.

No. 11 is a schematic cross-sectional view showing an example of an image recording device to which the present invention f: can be applied. Figure 2 (1) or Vl)
The following process (1) is performed in the image recording device shown in FIG.
The surface potential of the image bearing member (photoreceptor) at each location is shown in FIG. The photoreceptor 1 has a so-called Carlson-type structure in which five layers of light guides 1 are provided on a conductive base layer. Although any suitable photoconductive material such as Se, ZnO2, OPC, etc. can be used as the photoconductive layer, Se is used in this example.

In step (1), the surface of the photoreceptor 1 is uniformly charged by the corona discharger 2. Electrification is caused by the fluoroelectronic charge of Se)
It will last until Photoreceptor surface charge due to uniform charging (near'
V p is approximately 1ooov in the illustrated example.

In step (11), the surface of this uniformly charged body is irradiated with light as a first light information irradiation for parts of the recorded image other than the part to be printed in black (
3) in Figure 1. The intensity of this light irradiation t''6 The potential of the portion of the photoreceptor surface that has been irradiated with light falls to a potential below the intermediate potential v8 in the next step (approximately zero in FIG. 2 (IT)). be sufficient. The distributed light irradiation can be performed using transmitted light or reflected light from the original, laser beam scanning modulated by an image information signal, CRT spot scanning, or light from a light emitting element such as an LEP array.

The photoreceptor that has been irradiated with the first optical information is subjected to a positive corona discharge of the same polarity as the corona discharger 2 by the control corona discharger 11 in step (1[1), and as a result, in step (II ), the portion of the photoreceptor surface that was irradiated with light was approximately 50
It becomes a positive intermediate potential vg of 0v. This control corona discharger has a control grid, which has an intermediate
City f~'y, V! I K complementary fFT: is applied, and the sense) Y; Ot: 1 of the sense 10
: 141+ and changes in the intensity of the optical information irradiation light four times are compensated for (8 to 7) to make it possible to form a stable and good image fφ. At this time, the Jth, )Y, Information irradiation step (7) 'rF4.
f'+7. 'tit approx. 10 (with 10V, this is f-J: We form an area yY that suppresses positive corona discharge between part D- of the surface of the photoreceptor, several control corona boxes, and the control grid of the device 11. Then, in the process, the second light 1a is applied to the surface of the rS photoreceptor.
As a notification, the part of the recorded image to be printed in red is irradiated with light and sound (4 in Fig. 1).

The intensity of this light irradiation is a sufficiently low value (in this example, approximately 01 (IV)
It shall be sufficient to go down to

As described above, the first latent image corresponding to the image (q) portion that has a positive position 111 relative to the intermediate potential V8 and is to be printed in black, and the first latent image that has a positive position 111 relative to the intermediate potential V8, and A second latent image is formed on the surface of the photoreceptor 1, which has a negative potential and corresponds to the first image portion to be printed in red.

This photoreceptor is then subjected to one image, that is, developed, by the first developing device 5 in step (2) and then by the second developing device 6 in step (7). A developing slag bias voltage corresponding to the intermediate potentials v and l is applied to the developing sleeves of these developing devices, and ? The J1 developer 5 uses negatively charged black toner, and the second developer 6 uses positively charged red toner. Therefore, on the surface of the photoreceptor 1, in the step (V) using the first developing device 5, black toner is applied to the first latent image, and in the step (to) using the second developing device 6, the black toner is applied to the first latent image. 8
2 red for the latent image), the toner adheres, and the intermediate potential ■3
None of the toners landed on the area.

The thus developed photoreceptor is then sent to a corona discharger 7 to align the toner polarity, and then the toner image is transferred to a transfer paper 9 by a transfer corona discharger 8. In this way, the transfer paper 9 is a record that is printed in two colors, black and red, on a white background paper.

On the other hand, the photoreceptor after the transfer is used repeatedly after the residual toner on the surface is removed by the cleaning blade 11.

In the above image recording process, a first latent image is formed in a red image area, a second latent image is formed in a manner corresponding to a black image area, red toner is applied to a first imager, and red toner is applied to a second developer. Even if these latent images are developed using black toner, a two-color print image can be similarly recorded.

Next, an embodiment of the phenomenon method according to the present invention when applied to the image recording process described in -5 will be described with reference to FIG. In FIG. 3, 5 and 6 are 1fJ1. in FIG. f71
! These developing devices correspond to the container 5 and the second developing device 6, respectively.

In this embodiment, the developing device 5 performs jumping development using a one-component non-magnetic developer which is a black non-magnetic toner mainly composed of resin and does not contain carrier iron powder. The container 6 is used to carry out nodding development using a one-component magnetic developer, which is a red magnetic toner mainly composed of a magnetic material such as magnetite and resin, and does not contain carrier iron powder. Reference numerals 11 and 12 are cylindrical sleeves that are in contact with the l/ner supplied into the developing units 5 and 6, respectively, and are opposed to the photoconductor Y and photoconductor 1 at a distance of about 300μ. It rotates along the moving direction at a circumferential speed that is approximately equal to the moving speed. Inside the sleeve 12 of the magnetic jumping developer 6, a magnet 5 is provided which has a developing magnetic pole N at least at a position facing the photoreceptor. 13 and 14t'', a urethane blade having a hardness of about 60° is used as a toner coating blade, and depending on the R grade, the sleeves 1t and 12 are coated with toner to a thickness of 60 to 80/Z.

Incidentally, in order to stably coat the toner, the sleeve surface is provided with irregularities of R, 1 to 2 .mu.m. As the toner coating means, for example, a rotating roller, a brush roller, etc. can be used. In addition,
R7 does not represent surface roughness and has a standard length of 0°25w.
The roughness of R) was measured, a cross-sectional curve of 7 was drawn, and the distance between the 3rd and 11th peaks from the highest peak and the 3rd valley from the deepest valley was expressed in μm.

During this coating process, a triboelectric charge is applied to the toner from the sleeve surface. As explained in FIGS. 1 and 2 above,
When applied to the latent image forming process described above, the developing device 5
The toner ``tn'' and the charge control agent of each developer are selected so that the non-magnetic toner in the developing device 6 has a negative polarity and the magnetic toner in the developing device 6 has a positive polarity. ,
The entire charge described above may be applied directly to the toner coating on the sleeve using a corona charger or the like. Each sleeve 1
The toner coded as 1゜12-J: then approaches the photoconductor as the sleeve rotates, jumps from the sleeve to the photoconductor surface depending on the photoconductor surface potential, and adheres to the above-mentioned ff1l and i82 latent. Purify each image. In this case, the developing bias voltage and AC bias voltages 1.6 and 1.7 biased by a DC component voltage of +500 V are applied to each sleeve. Regarding the alternating current bias, please refer to the Japanese Patent Application Laid-open No. 1986-55 filed by the present applicant.
It is detailed in the publication No.-18657.

Next, the developing characteristics of the first and second developing devices will be explained with reference to FIGS. 4 and 5. Figure 4 shows the properties of jumping development using non-magnetic toner.

The horizontal axis shows the difference between the photoreceptor surface potential and the DC bias voltage, and the vertical axis shows the image density obtained by development. In order to obtain sufficient image density in the case of development using non-magnetic toner, the voltage vpp between peak values must be 2,000 µm as an alternating current component of the developing bias voltage in the 300 μg gap between the sleeve and the photoreceptor.
It is necessary to apply an alternating current voltage of V or more to force the toner to reciprocate violently between the sleeve and the photoreceptor to make it easier to adhere to the photoreceptor surface (this effect is tentatively referred to as toner activation).

In addition, in order to prevent fogging, it is necessary to set the AC component to a high frequency voltage of 2 kl (z or more.
-a is V, p = 2000V, frequency f = 2kTT
This is a characteristic curve when using an AC component voltage of z.

Same figure) 4-b is vT'p='. 2kv, f”=l
The characteristics when using the AC component voltage of OO0L1z are shown,
In this case, the toner activation is weak and the image density is insufficient.

FIG. 5 shows the characteristics of jumping development using magnetic toner. The meanings of the horizontal axis and R axis are the same as in FIG. Conditions 5-a and 5-b in the diagram are 4-a and 5-b in Figure 4.
Same as 4-b. This is an alternating current component with a lower frequency and lower voltage than in the case of non-magnetic toner, e.g. f I/: f
, f-1000Hl, Vp p ""1-2',<
V How much is 1 density of 1 monkey? ? ? It is being When using magnetic toner, a magnetic binding force acts in the developing section (the area where the photoreceptor and sleeve are close to each other); The main reason is that the magnetic toner fluffs up at a height of approximately 200 μC along the lines of magnetic force in the developing section, and the binding force due to the mirroring force that acts between it and the sleeve surface is significantly weakened. This is the current method using magnetic toner.
In this case, the same AC bias conditions as for one phase of development using non-magnetic toner, i.e., f=200 (IITz,
If Vpp is set to 2kV, the resulting image will have too much toner fog, which is not pleasing to the eye.

Based on the above, the first developing device 5 has f=2kHz.
.

V,,=20()OV AC component and "nc=+500V
A developing bias voltage superimposed with a DC component is applied,
Further, the second phenomenon generator 6 has f=l kHz, Vp=
It is desirable to apply a developing bias voltage in which an AC component of 1-2 kV and a DC component of vDc=+500 V are superimposed.

With this configuration, the non-magnetic toner deposited on the photoreceptor by the first developing device 5 does not form needle-like fuzz in the developing magnetic field of the second developing device 6. , it is not disturbed in the magnetic field. Under the above development bias voltage conditions applied to the shredded second developing device, the non-magnetic toner adhering to the photoreceptor is separated between the photoreceptor and the sleeve of the second developing device. It is also less likely to be activated.Therefore, it is possible to obtain a beautiful two-color coat without color mixing.

As described above, according to the present invention, the first developing step and the second developing step respectively visualize the first latent image and the second latent image corresponding to the image portions to be printed in two different colors. Both are jumping development using a one-component developer,
Furthermore, by using a non-magnetic toner in the first developing step and a magnetic toner in the second developing step, it is possible to obtain clear two-color copies without developer deterioration and color mixing.

Note that the above description of the embodiment is limited to the case of the latent image forming process "7" described in FIGS. 1 and 2, but the present invention d
Of course, other two-color latent image forming processes can also be carried out.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of an image recording nail/device to which the developing method of the present invention can be applied, and FIG. Figure 3 U1 is a schematic cross-sectional view of an example of a developing device for carrying out the developing method of the present invention. The figure shown in FIG. 5 is a diagram showing the development characteristics of the jumping developer using the magnetic toner shown in FIG. 1... Photoreceptor, 2... Corona discharger, 3
. . . Light irradiation corresponding to the first color image portion, 4 . . .
Light irradiation corresponding to the f-elemental part of the color image, 5...@1 developer,
6...Second developer, 7.8...Corona discharger, 9...Transfer removal, 1()...Cleaning grade, 11...Several boxes of control coronas, 2 11. 12...Developing sleeve, 13t14...What-Narcoding pad 1/-de, 15
···magnet. Figure 1'! ','r 2 Jl ↑ Fig. 3 Fig. 5 Scrap I 4 Good Story 1 艷I fL ~Vvc

Claims (1)

[Claims] A first developing step and a second developing step are performed in which different first and second latent images are formed on the image carrier surface jm, respectively, corresponding to image portions of two different colors, and toners having different colors are used. In an image recording process in which a two-color image is obtained by sequentially developing the first latent image and @2 latent image in a developing step, the first developing step is performed by jumping development using a one-component non-magnetic developer made of non-magnetic toner. and the second development step is carried out by shampooing development using a one-component magnetic developer made of magnetic toner.