JPS60143363A - Color recording device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of color mixture when recording operation is carried out for a long time by separating different-color toner which is mixed with a developer from the developer by utilizing the difference in sticking threshold electric field of the toner. CONSTITUTION:A toner image is already formed with the toner 24b of the 1st developing part on the surface of a photosensitive layer 11a which reaches the 2nd developing part, so part of the toner 24b may be separated from the toner image during the development of the 2nd developing part to mix in the layer of the developer 34 formed on the surface of a developing roller 22. The intermediate voltage between different sticking threshold electric fields of toner of the developers 24 and 34, however, is applied between the developing roller and a separating roller 31. Therefore, only the mixing toner 24b sticks on the surface of the separating roller 31 by the electric field and is separated from the developer, so the mixing of the different-color toner 24b with the developer 34 is prevented.

Description

Detailed Description of the Invention (al) Technical Field of the Invention The present invention relates to a color recording device using an electrophotographic recording method or an electrostatic recording method, and particularly relates to a color recording device in which color mixing does not occur even when recording is performed continuously. .

(bl) With the diversification of technological background information, colorization of output information is becoming required. Color recording and multicolor recording are no exception in the field of recording devices using electrophotographic recording methods and electrostatic recording methods. has been done.

In a recording device that uses such an electrostatic latent image, color recording is performed by sequentially repeating the latent image formation and development steps to visualize the latent image using toner of a different color in each development step. . In such a recording apparatus, consideration must be given to so-called color mixing, in which toners of different colors mix with each other, making it impossible to record in the original color.

(C) Prior Art and Problems The phenomenon of color mixing will be explained by taking a two-color color recording device that employs an electrophotographic recording method as an example.

In electrophotographic recording, the surface of a photosensitive drum is uniformly charged, a latent image corresponding to a first color image is formed using a laser beam, and a toner of the first color is supplied from a developing section to create the first color. A toner image is formed. By sequentially performing these steps a plurality of times, a composite toner image made of multicolored toners is obtained, and color recording is performed by transferring this composite toner image onto recording paper.

Focusing on the second developing section in such a color recording device, the second developing section supplies toner of the second color to the photosensitive layer on which a toner image of toner of the first color has already been formed. becomes. At this time, a portion of the toner constituting the first color toner image is peeled off and mixed into the second developing section. As a result, if recording is carried out for a long time, a problem arises in that toner of the first color accumulates in the developer in the second developing section, resulting in color mixture in the development at the second developing section. If the first color toner and the second color toner have charges of different polarities, it is relatively easy to separate them using the difference in polarity, but if the toner has the same polarity, Since it is difficult to separate the developer, conventionally, when color mixture occurs, all the developer is replaced. At present, the occurrence of color mixing shortens the life of the developer.

(d+ Purpose of the Invention In view of the above, the present invention separates toner of a different color mixed into the developer from the developer by utilizing the difference in the adhesion dark value electric field of the toner, thereby making it possible to record for a long time. The present invention provides a color recording device that does not cause color mixture.

(el Structure of the Invention For this purpose, the present invention provides a latent image forming medium, a charging means for supplying electric charge to the medium, and a latent image forming medium that forms an electrostatic latent image corresponding to an image to be recorded on the latent image forming medium. The method comprises a forming means, a plurality of developing means for visualizing the electrostatic latent image, and a transfer means for transferring the visualized toner image onto a recording sheet, and the charging, latent image formation and development are sequentially repeated multiple times. In a color recording device that forms a multicolor toner image on a latent image forming medium and then transfers the multicolor toner image all at once to the recording paper, the developer in each of the developing means has an adhesion darkness value of the toner. The electric fields are different from each other, and the second and subsequent developing means among the respective developing means have a separation roller provided close to the developer carrier, and there is a gap between the separation roller and the developer carrier. The present invention is characterized in that by forming an electric field, only the toner mixed in the developer in other developing means is made to adhere to the separation roller from the developer carrier and is separated from the developer.

(f) Embodiments of the Invention Below, embodiments of the color recording apparatus according to the present invention will be described in detail.

FIG. 1 is a schematic diagram of a two-color color recording apparatus employing an electrophotographic recording method. The recording device in FIG. 1 includes a photosensitive drum 11, a charger 12a, a first exposure section 13a, a first development section 14a, a recharger 12b, a second exposure section 13b,
It consists of a second developing section 14b, a transfer device 15, a static eliminator 16, a cleaner 17, and a static eliminator lamp 18.

A photosensitive drum 11 serving as a latent image forming medium has a photosensitive layer 11a on its surface and rotates at a constant speed in the direction of the arrow.

The charger 12a and the re-charger 12b charge the photosensitive layer 11a by supplying charges thereto. First exposure section 13a
The second exposure section 13b forms a latent image corresponding to the first color or second color image on the photosensitive drum Il by irradiating the photosensitive layer with laser light or the like. The first developing section 14a and the second developing section 14b form toner images by supplying toner of a first color and toner of a second color that are different from each other to the corresponding latent images, thereby visualizing the latent images. do. The transfer device 15 is a transfer corotron 15
a to transfer the toner image formed on the photosensitive drum 11 onto the recording paper 19. The static eliminator 16 neutralizes the charge 'on the photosensitive tram 11 and the charge held by the toner, thereby facilitating the removal of residual toner in the cleaner 17. The static elimination lamp 18 is used to keep the surface potential of the photosensitive layer constant, and exposes the entire surface of the photosensitive layer.

FIG. 2 shows the detailed structure of the developing section 14a, and FIG. 3 shows the developing section 1.
The detailed configuration of 4b is shown.

In FIG. 2, the developing section 14a includes a housing 21, a developing roller 22 as a developer carrier, and a doctor blade 23. The developing roller 22 includes a magnet roller 22a and a sleeve 22b made of a non-magnetic material (for example, aluminum).

The developer 24 is a two-component developer consisting of a carrier 24a and a toner 24b. The carrier 24a has a resistivity of 10 to 1
The toner 24b is a so-called microcarrier made of an abrasive material with a particle diameter of 5 to 50 μm and 0 Ωcm, and the toner 24b is made of an insulating nonmagnetic material. The sleeve 22b is fixed, and the developer 24 is conveyed in the direction of the arrow by rotating the magnet roller 22a in the direction of the arrow. The thickness of the layer of developer 24 is determined by the doctor blade 23. The developing roller 22 and the photosensitive drum 11 face each other so that the contact depth δ between the photosensitive layer 11a and the developer layer is maintained. Although not shown, a developing bias voltage is applied between the developing roller 22 and the photosensitive drum 11.

On the other hand, the developing section 14b has substantially the same configuration as the developing section 14a, but the two differ in the following points. That is, the third
As shown in the figure, the developing section 14b has a conductor separation roller 31 that faces the developing roller 22 with a gap therebetween and rotates in the direction of the arrow. It is desirable that the separation roller 31 be provided immediately after the developer 34 contacts the photosensitive layer. A power source 32 is provided between the separating roller 31 and the developing roller 22. This power source 32 forms an electric field between the separating roller 31 and the developing roller 22, and in this example, a DC voltage is applied between them as shown.

The developer 34 in the second developing section 14b is a two-component developer, and the carrier resistivity, particle size, etc.
This is the same as that of the developer 24 in , but the toner adhesion dark value electric field is different. That is, FIG. 4 is a toner adhesion characteristic diagram, where the horizontal axis represents the latent image intensity δ■, and the vertical axis represents the print density, ○, D value, the developer 24 is as shown in (A). When the latent image strength is 100V, the O and D values increase rapidly and the amount of toner 24b attached increases, but as shown in (B), the developer 34 has a ○ and D value until the latent image strength reaches 200V or more. does not increase, and the amount of toner 34b deposited does not increase rapidly.

Therefore, the toner 24b of the developer 24 is contained in the developer 34.
The voltage of the power supply 32 is set to 100ν and 2 to form an electric field between the separating roller 31 and the developing roller 22 even if
00v, it is possible to cause only the toner 24b from the developer 34 to adhere to the surface of the separation roller 31 without causing the toner 34b to adhere to the surface of the separation roller 31. The toner 24b attached to the separation roller 31 is removed from the surface of the roller 31 by the scraping plate 33.

Next, the recording process will be briefly explained with reference to FIG. Note that FIG. 5 shows the potential on the photosensitive drum in each step.

First, the surface of the photosensitive layer 11a is charged to the potential Vs by the charger 12a (FIG. 5(a)). First exposure section 13
a, a latent image corresponding to the first color image is formed (FIG. 5(b)). This electrostatic latent image has a developing bias voltage of V
Toner 24b of the first color is supplied to the first developing section 14a set to BI, and a toner image is formed and visualized (FIG. 5(C)). At this time, developing bias voltage VB
I is V 24 < VBI with respect to the dark value voltage V 24
It is set so that

Further, the potential of the image area of the first color is raised by the recharging device 12b (FIG. 5(d)), and the potential of the image area of the first color is raised (FIG. 5(d)).
A latent image is formed by the toner 34b of the second color by the second developing section 14b whose developing bias voltage is set to VB2 (FIG. 2(e)).
Figure 5(f)). At this time, similarly to the above, the developing bias voltage VB2 is set to V34≦V with respect to the dark value voltage V34.
It is set to be B2.

Therefore, when the photosensitive drum 11 passes through the second developing section 14b, a composite toner image of the two colors of toners 24b and 34b is formed on the surface of the photosensitive drum. This composite toner image is transferred to the recording paper 19 by the transfer device 15, and is fixed to the recording paper by passing through a fixing section (not shown). The photosensitive drum 11 after the transfer is transferred to a static eliminator 16,
The residual toner on the surface is removed by the cleaner 17 and the HFU lamp 18, and the potential is kept constant.

Now, if we pay attention to the second developing section 14b again, the developing section 1
Since a toner image by the toner 24b has already been formed on the surface of the photosensitive Ftlla that arrives at 4b, a part of the toner 24b is peeled off from the toner image during this development, and the developer formed on the surface of the developing roller 22 is removed. It may be mixed into the layer. However, since a voltage between 100v and 200v is applied between the developing roller 22 and the separating roller 31, only the mixed toner 24b adheres to the surface of the separating roller 31 due to the electric field and is separated from the developer. Therefore, the different color toner 2 for the IJA developer 34
4b contamination is prevented.

Although the above embodiment describes an electrophotographic recording method, it can be similarly applied to a recording device that forms an electrostatic latent image on a drum having an electrostatic recording layer using a pin electrode or an ion flow control method. can. Further, the present invention is not limited to two colors, and the same applies to multicolor recording using three or more colors. However, in this case, since the adhesion darkness value electric field of the toner in each developing section is different, it is necessary to vary the value of the voltage applied between the developing roller and the separating row in each developing section. Furthermore, the developer is not limited to a two-component developer, but can be similarly considered to be a one-component developer in which magnetic powder is included in the toner. Further, the separating roller 31 does not have a roller shape (or may have an endless heald shape).

Here, the developing method will be considered. Development methods are broadly divided into contact development methods and non-contact development methods. In the former method, development is carried out with the developer and the photosensitive layer in contact with each other. In the above embodiment, a soft developing method is described as a contact developing method in which the contact depth δ is reduced by using microcarriers having a small particle size, and the toner image that has already been formed is not destroyed.

On the other hand, in the non-contact development method, a photosensitive layer and a developer are placed facing each other with a gap interposed between them, and an AC or DC biased AC voltage is applied between the two to cause the toner to fly away and develop. More effective against destruction. The present invention can be applied to a recording device that uses any developing method, but in the case of a recording device that uses a non-contact developing method, the voltage applied between the developing roller and the separation roller is the same as that between the developing roller and the photosensitive layer. It must be an alternating current or direct biased alternating current voltage that is synchronized with the voltage applied to the

(g) Effects of the Invention As described above, according to the present invention, the adhesion dark value electric field of the toner of the developer in each developing means is made different, and the developer is carried on the second and subsequent developing means of each developing means. By arranging a separation roller provided close to the body and forming an electric field between the separation roller and the developer carrier, only the toner mixed in the developer in other developing means is carried on the developer. It is separated from the developer by being attached to the separation roller from the body. Therefore, it is possible to prevent toners of different colors from being mixed into the developer, and stable recording without color mixture can be performed without replacing the developer for a long time.

[Brief explanation of drawings]

The drawings relate to the present invention; FIG. 1 is a configuration diagram showing an outline of a two-color recording device using an electrophotographic recording method, and FIG.
FIG. 3 is a configuration diagram showing details of the first developing section 14a in FIG. 1, FIG. 4 is a configuration diagram showing details of the second developing section 14b in FIG. 1, and FIG. Figures 5 to 5 are potential diagrams showing potential changes on the surface of the photosensitive drum during each recording process. 14a14b is a developing section, 22 is a developing roller, 24.34 is a developer, 24a.2
4b is a carrier, 24a and 24b are toners, 31 is a separation roller, and 32 is a power source. Figure 4 (F) 1981 Patent Application No. 249296 20 Title of the Invention - Color Recording Device 3, Relationship with the Amendment Person Case Address of the Patent Applicant 1015 Kamiodanaka, Nakahara-ku, Yozaki City, Kanagawa Prefecture (
522) Name Fujitsu Ltd. Representative Takuma Yamamoto 4, Agent Postal code 211 Explanation” column and Drawing 8 Contents of amendment (1) “Cleaner 7 can be placed” on page 6, line 20 of the specification
is corrected to "in Cleaner 7." (2) "σV" on page 8, line 18 of the specification is corrected to "ΔV". (3) rV24J on page 10, lines 3 and 4 of the specification [
Corrected to 100VJ. (4) rV34J on page 10, lines 11 and 12 is corrected to ``200 people, IJ.'' (5) r24a and 24b on page 14, lines 8-9 of the specification.
--- is toner," is corrected as follows. r24a and 34a are carriers, 24b-34b are toner, 1'' (6) Figure 1 of the attached drawings is corrected as shown in the attached sheet. 9. 1 or more copies of the revised catalog of attached documents (Figure 1)

Claims (1)

[Claims] A latent image forming medium, a charging means for supplying electric charge to the medium, a latent image forming means for forming an electrostatic latent image corresponding to an image to be recorded on the latent image forming medium, and visualizing the electrostatic latent image. and a transfer means that transfers the visualized toner image onto a recording sheet, and the charging, latent image formation, and development are sequentially repeated multiple times to produce multicolor toner on the image forming medium. In a color recording device that transfers a multicolor toner image onto the recording paper at once after forming an image, the developer in each of the developing means has a different adhesion dark value electric field, and The second and subsequent developing means have a separation roller provided close to the developer carrier, and by forming an electric field between the separation roller and the developer carrier, the developer is mixed with the developer. A color recording apparatus characterized in that only the toner in the other developing means is separated from the developer by being attached to a separation roller from the developer carrier.