JPS6032189B2 - Two-color image reproduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image reproducing device in which an electrostatic recording device, like an electrophotographic device, visualizes an electrostatic latent image using a developer. The present invention relates to a two-color image reproduction device for continuously reproducing image information in one copy cycle.

Such reproduction devices usually form two electrostatic port images with different polarities on a carrier corresponding to a two-color original, and then process these images using two developing devices each using two different developers. Reproduce.

Development is performed by adsorbing toner in the developer, which is charged to a polarity opposite to that forming the static latent image, to the static latent image. Further, since the carrier holding the latent image is usually moving, when the developer that has been transported comes into contact with the carrier, the developer will rub the surface of the photoreceptor. Therefore, in the development process, two actions are simultaneously occurring: the action of the developer being adsorbed onto the surface of the carrier, and the action of the developer lacquering the surface of the carrier. When one latent image is developed simultaneously by two developing devices,
When performing the second development, the toner image developed by the first developing device has already been formed on the carrier, and the second development from above is performed.

Therefore, during the second development, the second developer rubs the surface of the carrier and scrapes off some of the first toner. The amount of the toner is not very large due to the large electrostatic attraction force between the toner and the surface of the damaged body, but due to repeated development, it gradually accumulates in the second developing device, and the amount of the second developer increases. This will reduce the saturation. The first toner is typically red and the second toner is black.
Therefore, the second toner is black played by red. When developing with such toner, an image with a dirty appearance is created. In this invention, the first toner mixed into the second developing device is electrostatically attached to a box-conducting surface provided in the second developing device, and the first toner is separated from the second toner. That is.

According to this invention, a developed image with high color saturation can be obtained with a simple device, and toner can be effectively reused.
Further, if this device is applied to an IJ cleaning device, it is also possible to separate two-color toners collected by the cleaning device. Accordingly, it is an object of the present invention to provide an improved two-color image reproduction device.

Another object of the present invention is to provide the above-mentioned apparatus in which the toner of the first color does not mix with the toner of the second color.

Hereinafter, the present invention will be described with reference to the attached drawings.

For convenience of explanation, the two colors to be reproduced are red and black. 1st
The figure schematically shows an electrostatic recording device to which the present invention is applied. The dielectric drum 1 is a dielectric drum coated with a humidifying material such as Mylar, and rotates at a constant speed in a counterclockwise direction. First, on the surface of the rotating dielectric drum 1, a static latent image of negative polarity corresponding to a red image is formed by the first multi-stylus 2. For example, a two-color original is separated into a red image and a black image based on the difference in spectral transmittance, these are read by an image sensor, each is stored in a storage device, and then a signal is sent to the multi-stylus 2 based on this. send and form. The multi-stylus 2 discharges in response to this signal, leaving a negative charge on the surface of the dielectric drum. Similarly, a positive electrostatic latent image corresponding to a black image is transferred to the second multi-stylus 3.
is formed on the surface of the rotary drum. For the electrostatic latent image consisting of charges of opposite polarity, first, positively charged toner is applied from the first developing device 4, and the electrostatic latent image corresponding to the red image is developed into red. The developing device is a magnetic brush type developing device that adsorbs developer onto a developing roller to form a magnetic brush, which is brought into contact with the electrostatic tank image to perform development. There are two types of developers: two-component developers consisting of toner and carrier, and one-component developers consisting only of toner. This invention can use any developer.
After the red color development is completed, negatively charged black toner is applied from the second developing device 5 to the dielectric drum surface, and the electrostatic latent image corresponding to the black image is developed into black color. The two-color toner image on the dielectric drum obtained by red development and black development has its charging polarity made uniform by a corona discharger 6, and then transferred to a transfer roller via a fed transfer paper 7. The image is exposed under the discharge device 8 and transferred to the transfer paper 7.
The surface of the transfer body is then wiped by a cleaning brush 9 to remove toner remaining on the surface, and further, the potential remaining on the surface is removed by a static eliminating corona discharger 10. Next, the second characteristic part of this invention is
The developing device will be explained with reference to FIG. The structure of the developing section is similar to that known in the art. That is, an impeller 12 , a pumping roller 13 , and a developing roller 14 are arranged within the developing container 11 . The developer 15 housed in the developer container 11 is impeller 12 and the toner in the developer is frictionally charged to a predetermined polarity, in this case negative. The developer is then transported from the pumping roller 13 to the developing roller 14, and on the way, the developer is transported to the developing roller 14.
After the amount of adhesion is regulated by 6, the dielectric drum 1
to develop a static latent image. The pumping roller 13 and the developing roller 14 each include a rotating non-magnetic sleeve 13a, 14a, and a magnet 13b, 1 having a plurality of magnetic poles on the circumferential surface stationary therein.
4b. The developer on the developing sleeve 14 that has completed development is scraped off by the scraping plate 17,
It is collected into the developer container 11. The toner separation device is continuously provided on the side of the developing device.

The scraping plate 17 has a gently curved portion at its lower portion, and a conductive roller 18 is rotatably disposed at a predetermined interval in this portion. A partition plate 19 is vertically provided below the leaching roller 18 to separate the developer container 11 and the separation container 21 from each other. A scraping plate 20 is provided on the side wall of the separation container 21, and its tip is attached to a conductive roller 18.
It is placed in contact with the surface. In this example,
A negative potential is applied to the conductive roller 18 and the scraping plate 1
A bias power supply V is connected between them so that a positive grounded potential is applied to them. As described above, in the two-color development apparatus, when the two-color development device performs development, a toner image is already formed on the object by the first development.

Therefore, when performing the second development, the second developer rubs this toner image. Some of the toner is thereby scraped off and mixed into the second developer. In this embodiment, the positively charged red toner image 22 already formed on the dielectric drum 1 is transferred to the developing sleeve 1.
After being slightly scraped off by the black developer on 4, the developer is scraped off from above the developing roller by the scraping plate 17, and flows down on the scraping plate 17.

These are the scraping plate 17 and the conductive roller 18.
When passing between
- The positively charged red toner is adsorbed on the surface of the film 18 and is separated from the black developer. The black developer is collected as is in the developer container 11, and the red toner adsorbed on the surface of the conductive roller 18 is removed by the scraping plate 2.
01 thus scraping off the roller surface and separating container 21
will be collected within. If the separation of the red toner from the black developer or black toner is also carried out on the toner collected by the device for cleaning the toner image carrier, that is, the device shown at 9 in FIG. 1, the toner can be reused. It is valid. For this purpose, the duct 23 is connected to the cleaning device 9, and a suction device (not shown) is used to
The toner collected by the cleaning device is guided into the duct, and the lower end of the duct is connected to a separating device to cause the toner to flow down onto the scraping plate 17. In this way, toner separation in the developing process and toner separation in the cleaning process can be performed simultaneously using one separation device. Although the illustrated embodiments have been described above, the present invention is not limited to the above embodiments.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of an electrostatic recording device to which the present invention is applied, and FIG. 2 is a schematic diagram showing an example of a developing device to which an embodiment of the present invention is applied. 1: dielectric drum, 2, 3: multi-stylus, 4: first developing device, 5: second developing device, 18: conductive lo-fu, 23: tact. Disliked vulgar illustration 2

Claims (1)

[Claims] 1 In response to image information expressed in two colors on a white background,
In a two-color image reproducing device, two latent images with different polarities or potential differences are formed on a carrier, and these are continuously reproduced by two developing devices each using two different color developers. The first developer that is about to enter the second developing device is adsorbed to a conductive surface to which a polar potential that electrostatically attracts the first developer is applied, thereby causing the first developer to A two-color image reproducing device characterized in that a second developer is separated from a second developer.