JPS5931970A - Two-color developing method - Google Patents

Abstract

PURPOSE:To prevent mixing of each color toner, by carrying out jumping development for each of the first and the second developing processes using a one-component type magnetic developer, and using the magnetic toner for the second process having a magnetic dipole moment higher than that of the toner used for the first. CONSTITUTION:Each of the first and the second developing devices 5, 6 uses a one-component type magnetic developer and carries out jumping development, but the magnetic toner of the device 5 is lower in dipole mement than that of the device 6, and the former is black and the latter is red. The first latent image to be printed with a black color haiving positive potential with respect to the intermediate potential Vs of a photoreceptor 1, and the second latent image to be printed with a red color having negative potential are formed on the photoreceptor 1. The developing sleeves 11, 12 of the devices 5, 6 are subjected to a developing bias voltage corresponding to the potential Vs, and the negarively charged black toner is used for the device 5, and the positively charged red toner is used for the device 6. As a result, the black and red toners are attached to the first and second latent images on the photoreceptor 1 with the devices 5, 6, respectively, and no toner is attached to the part having the intermediate potential Vs.

Description

[Detailed description of the invention] The present invention uses tatami-shaped two-color 1.su~ to 1σ+i (
In recent years, with the spread of computer facsimiles and the like, there has been an increasing demand for the ability of printers to output data. For one thing, we would like to improve usability and arouse user favor by making Bunsei printed out by a printer in two colors, including not only black but also red, for example. There is a demand for this. Conventionally, electrophotographic processes have been proposed that require two-color printers, but they have the disadvantage that the two-color toners tend to mix. The reason for this is that the developing device used in these processes uses iron powder as a carrier, and toner is added to this as a carrier.
It is a so-called two-component developer that uses a two-component developer mixed with 1. When rubbing the toner image in the first developer unit), the toner image of the first color/color is rubbed off. In this case, it becomes difficult to see the toner on the photoreceptor in both the first and second JJI I detectors, and the toner image of the first color is damaged when the second developing device rubs the photoreceptor. The reason is that it becomes easier to

The present invention provides a new two-color development method that prevents defects and makes it possible to darken each toner cartridge when performing the first and second development steps sequentially using two different color toners. ll
f: The purpose is to provide a jumping development method using a one-component abrasive developer made of a magnetic toner that does not cause deterioration in both the first and second development steps.
'4S, and the magnetic dipole moment of the magnetic toner used in the second development step is made wider and louder than that of the magnetic toner used in the first development step.

An example of glue 8/1llj of the present invention will be explained below.

1 is a schematic cross-sectional view showing an example of an image recording apparatus r1' to which the present invention is applied. Figure 2 (1) No L (Vr
) Vi, gB 1 wall support (photoreceptor) that goes through the following steps (11 to ■) performed in the image recording device shown in Figure 1
The horizontal axis shows the surface position of the photoreceptor, and the vertical axis shows the position of Nu, If & jY=body surface Jtv. The photoreceptor 1 is a so-called Carlson type photoreceptor in the form of a drum, which is formed by providing a photo conductor on a conductive base layer, and rotates in the direction of the arrow. Light guide τ; A layer is Se
Although any suitable photosensitive material such as ZnO2+OPC can be used, Se is used in this example.

In step (1), the surface of the υ photoreceptor 10 is uniformly charged by the corona discharger 2. Charging is carried out to the level of the charged photovalley of Se. Photoreceptor surface due to uniform banding? The voltage around tt is approximately 1000V in the illustrated example.

In the step (III), the uniformly charged surface of the photoreceptor is irradiated with light as the first light information irradiation for parts of the recorded image other than the parts to be printed in black (3 in Fig. 1). The intensity of the light irradiation is sufficient to lower the part 1b of the surface of the photoreceptor that has been irradiated with the light to a potential below the intermediate potential v8 in the next process (1 (III) (approximately zero in Figure 2 (Ill)). ": nl, ': Light irradiation is transmitted light or reflected light from the original, or image information is laser pre-tracing AF modulated by <, CILT spot scanning difference or L.
This can be performed using light from a light emitting element such as an EP array.

The photoreceptor that has been irradiated with the first optical information is then irradiated with the corona discharger 1 by the control corona discharger 11 at the -[culm (III)].
1 is subjected to positive corona radiation t4j of the same polarity as vessel 2, and as a result, the portion of the photoreceptor surface that was irradiated with light in the step (Ill) becomes approximately 500 V +E intermediate 1b1 position v8.This 1ltll i The +IL corona emitter has a control grid, to which a voltage LF corresponding to an intermediate potential v8 is applied, which controls fluctuations in the sensitivity of the photoreceptor 1 and the optical information irradiation light. Compensate for undesirable fluctuation factors such as intensity changes l1rIJ to ensure stable and good image formationii
It is classified as J-Noh. At this time, the first optical information irradiator f
'- That is, the potential of the part of the surface of the photoreceptor that was not exposed to light in step ([1] is about 1.0 Ofl V, which is the same as that of the part of the surface of the photoreceptor and the number of control corona boxes and the container 11.
Since an electric field is formed between control gate and gate to control the positive corona radiation tb, it is maintained at that level.

Next, in IVI, the surface of the photoreceptor is irradiated with light for 111X minutes of the recorded image to be printed in red as second light information irradiation (4th part A-4).

The intensity of this light irradiation is such that the potential of the part of the surface of the 118-element body irradiated with light is sufficiently low 110 (in this example, about +
100 V).

As described above, the first position corresponding to the image portion to be 7° linted in black with a positive position relative to the intermediate position V, and the intermediate position V, 411 for potential
In contrast, a second latent image corresponding to the image area to be printed in red is formed on the surface of the photoreceptor 1 by placing the fifth position in the negative box 11.

This feeling) "l, the body is developed by the current tester 5 as step tV+, and then developed, or converted into a nod, by the second tester 6 as a goni culm (■). These images are '3A A developing/minus voltage corresponding to the intermediate potential v8 is applied to each of the developing devices (IJ-Z), and the first developing device 5 carries black toner charged to 84, and the second developing device 6
A positively charged red toner is used. Therefore I+B+
8 Summer vacation 10, black toner is applied to the first latent image in step (V) by the first developing device 5, and black toner is applied to the first latent image by the second developing device 6] l &! (In (■), the red toner adheres to the second latent part, and as in t, no toner adheres to the intermediate potential 78 part.

The photoreceptor thus developed is then heated in a corona discharger 7, where the polarity of the toner is aligned, and the toner image is transferred to
It is transferred to a transfer paper 9 by a corona expeller 8 for use in corona. Transfer paper 9 is printed in two colors, black and light, on paper with a white background color.
01 After the residual toner has been removed, λ2 is used for repeat 1 history.

In addition, the second latent image is formed on the entire red image part of the first latent image, and the second latent image is formed on the black [printed image part], and the first developing device Even if these latent images are developed using red toner in the second developing device and black toner in the second developing device, a two-color print image can be similarly recorded.

Next, an embodiment of the developing method according to the present invention when applied to the above-described image recording process will be described with reference to FIG. In the figure, 5 and 6 are the first developing device 5 and the second developing device in FIG.
These developing devices correspond to the developing device 6, respectively. In this embodiment, both the developing units 5 and 6 perform jumping development using a one-component magnetic developer, which is a magnetic toner mainly composed of a magnetic material such as magnetite and resin, and does not contain carrier iron powder. This is what we do. However, the magnetic toner in the developing device 5 has a smaller magnetic dipole efficiency than the magnetic toner in the developing device 6; in this embodiment, the former is black and the latter is red. Reference numerals 11 and 12 indicate sleeves in contact with the toner in the developing units 5 and 6, respectively, and the sleeves are approximately 300 mm in contact with the photoreceptor 1.
Inside each sleeve 11 and 12, which rotate at a circumferential speed approximately equal to the moving speed rw of the photoreceptor along the moving direction of the photoreceptor, there is a developing device at least at a position facing the photoreceptor. A magnet 15 having magnetic poles N is provided.

Reference numerals 13 and 14 denote toner coating blades, which are urethane blades having a hardness of about 60 degrees, and coat the sleeves 11 and 12 with toner to a thickness of 60 to 80 microns. Incidentally, in order to stably coat the toner, irregularities of t and R2 = 1 to 2 .mu. are formed on the sleeve surface. Illusion as a toner coating means:
In addition, for example, a Li micro roller, a brush roller, a magnetic blade, etc. can be used. Note that R2 is a value that represents the surface roughness, and the standard length is 0.25++ m)
4, 1, 1. The distance between the third deepest peak and the third deepest valley is expressed in μm't'.

During this coating process, the toner is given a triboelectric charge from the sleeve surface. The stand used in the latent image forming process explained in FIGS. 1 of the polarity of The toner material of each developer, the load 'N'i, and the control agent are selected so that the load is applied. Of course, the toner coating on the sleeve may be directly charged with the above charge using a corona charger or the like. As the sleeves rotate, the toner coated on the sleeves], 1, and 12 reaches the developing section (close to the photoconductor (#j)), and is transferred from the sleeve to the photoconductor according to the sensor surface detection 0T. The aforementioned first and second latent images are developed by jumping onto the surface.

In this case, each developer is provided with a developing electrode at a portion facing the photoreceptor within each sleeve 11.12, and a developing bias 'I0° pressure, which will be described later, is applied to each developing electrode. There is.

The magnetic property of the toner used in the second developing device (in particular, the magnetic dipole efficiency of the toner is 1111, which is larger than the magnetic dipole efficiency of the toner used in the first developing device). It is important to determine the content.In this embodiment, the resin content of the toner in the first developing device is 25 to 40 parts when the resin content is 100 parts. The number of zoki ware is estimated to be 50 to 100 copies.

It is also important to set the magnet 15 in each developing device so that the magnetic flux strength on the sleeve surface of the second developing device is weaker than that of the first developing device. In this embodiment, the magnet 15
uses anisotropically magnetized strontium barium ferrite, which is placed close to the inner surface of the sleeve, and the first
The strength of the four bundles on the sleeve surface of the imager 5 is approximately 1400.
G * binding, and the second developing device 6 was set so that the surface of the sleeve was about half that, 700 G.

The above-mentioned magnetic toners exhibit similar development characteristics when each developing device is operated. The magnetic suction hopper acting on the magnetic toner on the surface of the sleeve redraws the magnetic toner fK:, the old-style brush, and the sleeve θ Here, l-1 is the magnetic field strength or the radial distance of the sleeve, M is the magnetic dipole efficiency of the toner, and MQ'
: is proportional to the amount of magnetite n in p cotoner.

θH / F The force F is I for each developer.
'1 is an equal relationship.

In addition, in the jumping phenomenon using magnetic toner, each phenomenon
ll'II between the photoreceptor and the sleeve surface for both 4 units 5 and 6.
As mentioned above, the frequency f at the development phase pole is about 600 to 120 (l Hz, and the peak value to fE Vpp is 1000 to 1500 V.
Applying the current bias vehicle pressure which is a combination of the current flow pressure and the first flow Ichikawa VDC, the toner is violently reciprocated between the photoreceptor and the sleeve curve, and is deposited on the surface of the photoreceptor. (called activation) is necessary. In the upper Li embodiment, the AC component of the current bias voltage is 1 f = 1 (1 (1
011z TVpp"1200V, DC component vnc
'f'+500V.

(The cross-11fi bias is described in detail in Japanese Patent Application Laid-Open No. 55-18657, which concerns the entry and exit of people 111.) In this way, magnetic toner is
An advantage of applying the l+ field is that the toner can be easily made viscous. In other words, (1t) (JIJ made the old brush for air bacteria*, l-toner also between the sleeve surface (Kaitot, 1, toner in the Kobanichi 1 world with no effect at all and relatively low) can be activated.

Now, regarding the magnetic toner conditions mentioned above, the sleeve surface magnetic flux strip 1'
1 and development bias conditions, when the first development using the ε[41 developer and the second development using the second developer are performed,
It is possible to see the image 14I2 printed in two colors.
” Becomes Noh. To explain this, first development is performed, and toner having a relatively small amount of magnetite and therefore having a relatively small magnetic dipole efficiency is first deposited on the surface of the photoreceptor in the first fully populated area.

Next, the second wave 1 is carried out, and the second wave 1 is deposited on the surface of the photoreceptor.
The second toner, which has about twice the amount of magnetite as the first toner, is applied to the square part, and the second toner, which has about twice the rate of magnetite, is applied. During the second development, the second toner e is heated in the form of a brush by the action of the magnetic field, by applying a sufficient magnetic binding force to the sleeve surface. On the other hand, nine body surface U? -('I;Fr
t Naka'j < hi, 4 energy is about 1/2 of the IQ of the second toner, and the first toner with that C11 is 2152 current 1! The photoreceptor vv becomes reliable Sword 1 without being transferred to the sleeve of the device. Also, during the second development, 7i-ryu Ichitake is applied between the sleeve and the photoreceptor, but since the P02 toner is formed in a brush on the sleeve, it is easily activated by the alternating current electric field. On the other hand, the first toner (R), which is attached to the photoreceptor, has a weak brush-like force and is not easily activated in the father's td field, so it adheres to the photoreceptor. can maintain its condition.

As explained above, according to the present invention, two different colors are used for each glint image If tili. i・；、
The first manifestation that manifests the first latent image and the second evil source, respectively.
Since the development process is all jumping development using a one-component developing agent other than magnetic toner, it is possible to produce two-color recorded images with no decrease in image density. In addition, in order to keep the 4+n twin 1 particle efficiency of the toner used in the first development process smaller than that of the toner used in the second development stage, the first development process The toner gaps formed in step (1) are not disturbed during the second development, making it possible to obtain a stable recorded image without color mixing.

Although the description of the embodiment is limited to the case of two latent ends of opposite polarity, the developing method of the present invention can also be applied to the case of two latent ends of the same polarity by selecting the magnetic dipole efficiency of the toner. is valid.

[Brief explanation of the drawing]

FIG. 1 shows an image recording apparatus 11) to which the phenomenon method of the present invention is applied. FIG. 2 is a schematic sectional view of an example of (11 or Vl)
) is the image in Figure 1 of the NIJ recording equipment during the process)
FIG. 3 is a schematic cross-sectional view 1i#1 showing an example of a developing unit for carrying out the developing method of the present invention. 1: photoreceptor, 2: colono discharger, 3: light irradiation corresponding to the first color image portion, 4: second FQ image 14
In 4 parts? l W,, do) Y4 Terugyu 1.5: 1st present device, 6: 2nd present It r total, 7.8: Corona release +ij, vessel, 9: kan'q month, ] 0: Cleany ng grade, 11: Corona width for 1tflLiIllI', 7
+iT%+1.12: Current 1st yield sleeve, 13, 14:) Su-coating grade. 15: (+ and 4 stones. Figure 1 21・'1 Figure 3

Claims (1)

[Claims] 1 Two-color images 1 (corresponding to 11 minutes) are formed on the surface of the image carrier, and toners with different colors are used. 1st and 2nd current II L
In the double image recording process in which the first and second latent images are developed with 111"I (K) to form a two-color image, both the first and second development steps are performed using a one-component magnetic developer made of magnetic toner. According to the shampooing ring rq! using Nishikigen 1'Tanoj that is 1 Samurai 1 Kai
Law.