JPH04104279A - Liquid developing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of breaking and missing in the reproduction of an electrostic latent image by providing a liquid toner supplying part having a slit-like liquid toner supplying path and a slit-like opening part, and a toner supplying path opening/closing means opening/closing the slit-like liquid toner supplying path. CONSTITUTION:Liquid toner 1 is continually supplied to the slit of the top end part of a slit head 2. A liquid toner grain quantity controller 6 composed of a piezoelectric element 5 and a liquid toner partition pat 4 is installed in such a manner than the controller 6 is protected by an elastic liquid toner partition sheet 3, on the top end part of the slit head 2. The piezoelectric element 5 has the application of a pulse voltage, to be vibrated, and allows the liquid toner partition pat 4 to repeat is its action from a state where the liquid toner supplying path body 4 is released to a state where it is closed. In the state where the liquid toner supplying path is closed, the liquid toner quantity of the top end part is kept constant, and in the where the liquid toner supplying path is released, the liquid toner 1 is supplied. Thus, the occurrence of the breaking and missing in the reproduction of the electrostatic latent image is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device used in an electrostatic image forming apparatus, and particularly to a developing device using a liquid developing material.

[Conventional technology]

Conventionally, in recording processes such as electrophotography, electrostatic recording, and ionography used in copying machines and printers, basically an electrostatic latent image formed on an electrostatic latent image carrier is visualized using a coloring material. By doing so, records are obtained. Various methods have been proposed for creating an electrostatic latent image, such as exposing a negatively charged photoconductive material to light, and forming an electrostatic latent image on a dielectric material using a multi-needle electrode or an ion emission gate. In addition, there are those in which the electrostatic latent image carrier is used as the final recording medium,
There are various types, such as those that transfer a visualized baton from an electrostatic latent image carrier to a recording medium, but the so-called development process that visualizes an electrostatic line image with a coloring material is common to these recording methods. be. Further, developing methods are broadly divided into dry developing methods that use powder toner as a colored material and wet developing methods that use liquid toner. In the dry development method, the magnetic brush development method, in which the toner is transported to the development area using magnetic force, is currently widely used, but since powdered toner is used as the colorant, toner powder smoke is generated. There is a problem that it is easy to stain the inside and outside of the apparatus, and another disadvantage is that a fixing process that applies heat and pressure is essential in order to fix the powder toner image to the recording medium.

On the other hand, in the wet development method, the electrostatic latent image medium is immersed in a liquid developer in which colored particles are dispersed in a highly resistive organic liquid, and the electrostatic latent image is developed by electrophoresis of the colored particles. However, there are problems such as colored particles adhering to the background area that is not developed and causing background smudges, and the need to dry the organic liquid in the dispersion medium, which increases the concentration of organic liquid vapor around the device. there were. As a liquid developing method that solves these problems, US Pat. No. 4,202,620 proposes a method of developing an electrostatic latent image by bringing a thin layer of liquid toner close to the electrostatic latent image carrier without contacting it. In connection with this method, a method has been considered in which liquid toner is brought close to the latent image carrier using a slit head.

FIG. 4 shows a conventional recording process using a slit head. The leading slit of the slit head 13 is uniformly filled with liquid toner 1, and the liquid toner 1 is constantly supplied to the slit from inside the slit head 13. Then, the slit head 2 is brought close to the latent image carrier 7 on which the latent image is recorded to perform development. Next, Fig. 5(a) to Fig. 5(C)
2A and 2B show cross-sections of the developing process viewed from the direction along the central axis of the latent image carrier. In the figure, the left side corresponds to a solid black portion, and the right side corresponds to an area where separated electrostatic latent images 10 are present closely (see FIG. 5(a)). When the liquid toner 1 supplied to the slit by the slit head 2 approaches the electrostatic latent image 10, it is attracted by the electrostatic latent image 10, and the liquid toner projections 11 move toward the electrostatic latent image 10.
Since the liquid toner 1 comes into contact with and adheres only to the electrostatic latent image 10 formed by the electrostatic latent image 10, development is performed without background smearing and without adhesion of excess dispersion medium.

[Problem to be solved by the invention]

In this conventional method, the protrusions formed from the liquid toner 1 supplied by the slit head 13 overlap the electrostatic latent image 10 on the latent image carrier 7 and the irregularities caused by minute fluctuations on the free surface of the liquid toner 1. Since the electric field is generated in the area where the electric field is concentrated between the (meniscus) and the --like solid black area, protrusions are unevenly generated, and uniform solid black development cannot be achieved, resulting in defects such as omissions. Also, if a -degree protrusion occurs,
Since there is an effect that the electrical contact is increasingly concentrated in that part, for electrostatic latent images that are close together, multiple protrusions are not formed individually for each electrostatic latent image part, but at that time. Only one protrusion formed reaches the electrostatic latent image.

For this reason, there was a problem in that a fine electrostatic latent image could not be reproduced and would be destroyed. Furthermore, due to the surface tension of the liquid toner, a so-called bridge 12 occurs, which is a phenomenon in which the protrusions of the liquid toner adhere continuously to the latent image carrier 7 and cannot be separated (see FIG. 5). c) see)
.

[Means to solve the problem]

In the present invention, when an electrostatic latent image formed on a latent image carrier is visualized with a colorant, a meniscus of liquid toner is held close to the latent image carrier without contact, and the electrostatic field is In a liquid developing device that performs development by attracting the liquid toner, the liquid toner supply section includes a slit-shaped liquid toner supply path and a slit-shaped opening, and a toner supply path that opens and closes the slit-shaped liquid toner supply path. It consists of an opening/closing means. Further, the slit-shaped opening of the liquid toner supply section may be provided with regularly arranged partition plates, and further, the toner supply path opening/closing means may be provided with a vibration control mechanism using a pulse voltage.

〔Example〕 Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) and 1(b) are partial sectional views showing one embodiment of the present invention. In FIG. 1(a), liquid toner 1 is constantly supplied to a slit at the tip of a slit head 2. In FIG. A piezoelectric element 5 is provided at the tip of the slit head 2,
A liquid toner particle amount control device 6 consisting of a liquid toner partition bat 4 is protected by a stretchable liquid toner partition sheet 3, and a piezoelectric element 5 vibrates when a pulse voltage is applied to it. The operation of the liquid toner partition bat 4 from opening the liquid toner supply path as shown in FIG. 1(a) to closing the liquid toner supply path as shown in FIG. 1(b) is repeated. Then, the amount of liquid toner at the tip is kept constant while the liquid toner supply path is closed, and the liquid toner 1 is supplied while the liquid toner supply path is open.

FIG. 2 is a perspective view showing the appearance of FIG. 1. In FIG. 2, the slit at the tip of the slit head 2 is divided by liquid toner partition plates 9 arranged at equal intervals. Then, the liquid toner 1 is atomized in a constant amount by the slit head 2, the liquid toner particle amount control device 6, and the liquid toner partition plate 9 to form liquid toner particles 8.

FIGS. 3(a) to 3(b) are cross-sectional views showing the operation of the developing process according to the embodiment of the present invention, as viewed from the direction along the central axis of the latent image carrier. The left side corresponds to a solid black area, and the right side corresponds to an area where separated electrostatic latent images 10 are present in close proximity. FIG. 3(a) shows a state in which the electrostatic latent image 10 on the surface of the latent image carrier 7 approaches the liquid toner particles 8, and before the liquid toner particles 8 are attracted by the electrostatic latent image 10. It shows the status of. The liquid toner particles 8 are attracted to the electrostatic latent image 10, and each liquid toner particle 8 is shown in FIG.
As shown in b), each electrostatic latent image 10 becomes a liquid toner protrusion 11, which grows and moves to the surface of the latent image carrier 7. At this time, the amount of liquid toner particles that move to the surface of the latent image carrier 7 is kept at a limited amount, so unlike the conventional method, the liquid toner particles are supplied one after another, and because the particles are atomized, At that time, there is no possibility that only the first protrusion is formed, as shown in Fig. 3 (C
), the reproduction of the electrostatic latent image 10 may be crushed or missing, or the surface tension of the liquid toner may cause the liquid toner protrusion 11 to become stuck between the slit head and the latent image carrier 7. There is no problem of so-called bridging, which is a phenomenon in which the adhesive sticks continuously and cannot be separated.

〔Effect of the invention〕

As explained above, the present invention includes liquid toner partition plates regularly arranged in the slit at the tip of the slit head, and an integrated toner particle control device that vibrates by applying a pulse voltage to a piezoelectric element. This has the effect of preventing problems such as the reproduction of electrostatic latent images being distorted or missing, and problems such as bridging of liquid toner.

A cross-sectional view showing the operation of the developing process according to the embodiment, FIG. 4 is a perspective view of a conventional liquid developing device, and FIGS.
C) is a sectional view showing the operation of a conventional developing process.

1...Liquid toner 2...Slit head, 3...
-Liquid toner partition sheet, 4...Liquid toner partition bat, 5...Piezoelectric element, 6...Liquid toner particle control device, 7...Latent image carrier, 8...Liquid toner particle, 9・
...Liquid toner chamber partition plate, 10...Electrostatic latent image, 11
...liquid toner protrusion, 12...bridge.

Claims (1)

[Scope of Claims] 1. When an electrostatic latent image formed on a latent image carrier is visualized with a colorant, a meniscus of liquid toner is held close to the latent image carrier without contact; In a liquid developing device that performs development by attracting the liquid toner using an electrostatic field, the liquid toner supply section has a slit-shaped liquid toner supply path and a slit-shaped opening, and the slit-shaped liquid toner supply path is opened and closed. 1. A liquid developing device comprising a toner supply path opening/closing means for opening and closing a toner supply path. 2. In the slit-shaped opening of the liquid toner supply section,
2. The liquid developing device according to claim 1, further comprising regularly arranged partition plates. 3. The liquid developing device according to claim 1 or 2, wherein the toner supply path opening/closing means has a vibration control mechanism using a pulse voltage.