JPH01138570A - Image forming method - Google Patents

Abstract

PURPOSE:To prevent base fogging by uniformly electrifying a dielectric to polarity opposite from toner, impressing developing bias polarity with voltage whose polarity is opposite from the toner, impressing back plate with the voltage corresponding to an image signal and forming a toner image on the dielectric. CONSTITUTION:The dielectric 2 is uniformly electrified to the reverse polarity of the toner 10. The bias voltage Vb whose polarity is opposite from the toner 10 impressed on the developing bias polarity 8 which serves also as a toner 10 carrier, and the voltage Vp according to the image signal 4 is impressed on the back plate 3. The toner 10 is scattered by means of an electric field generated between the developing bias polarity 8 and the back plate 3 so as to form the toner image on the dielectric 2 according to an image. At that time, static electricity combines the toner 10 scattered by electric charges whose polarity is opposite from the toner 10 uniformly electrified onto the dielectric 2 with the dielectric 2, thereby strengthening adhesive strength between the toner 10 and the dielectric 2 and preventing the toner 10 from scattering when developing isn't performed. Thus, the base fogging can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an image forming method in which a toner image corresponding to the image is directly formed on a dielectric material using toner without forming a latent image in advance.

BACKGROUND ART Conventionally, as an image forming method in which a toner image is directly formed on a dielectric material according to the image using toner without forming a latent image in advance, a dielectric material (14) is formed as shown in FIG. Hold it with a magnet (
18), l-ner carrier (17) and control electrode (1
6), a multi-needle electrode (13) is arranged, and a voltage according to the image signal (19×20) is applied between the multi-needle electrode (13) and the control electrode (16) to generate a dielectric There is one that deposits toner (15) on the body (14) to form a toner image. In this method, when the voltage is applied, the toner (15) is moved by electrostatic force to the dielectric (
14). Dielectric (1
4) Selectively charge the toner (15) with a multi-needle electrode (13) from the back side to a polarity opposite to that on the multi-needle electrode (13) side, and adhere the toner (15) to the dielectric (14). That's why. Therefore, in the development using electrostatic adsorption as described above, the toner (15) attached to the dielectric (
14) can only be expected to be held by electrostatic force due to the internal polarization of the dielectric (14) caused by the charge of the attached toner (15), and is very weak. could scatter, causing smudges on the image. Furthermore, in the above image forming method, the toner carrier (17) is rotated by the circular force caused by the rotation of the toner carrier (17).
7) So-called background fogging occurs in which the toner (15) on the surface is scattered onto the dielectric (14).

In this invention, in a method of directly forming a toner image according to the image on a dielectric material using toner without forming a latent image in advance, the adhesion force between the dielectric material and the toner is weak, so that the toner that has adhered once scatters. However, the problem is that the image becomes smudged.
Furthermore, it is an attempt to solve the problem of so-called background fog, in which the toner on the toner carrier is scattered onto the dielectric material during non-development due to the centripetal force caused by the rotation of the toner carrier.

Means for Solving the Problems As a means for solving the above problems, the present invention provides a method of directly forming a toner image corresponding to the image on a dielectric material using toner without forming a latent image in advance. The dielectric is uniformly charged to the opposite polarity to that of the toner, and a bias voltage having the opposite polarity to that of the toner is applied to a developing bias electrode that also serves as a toner carrier, and the dielectric is sandwiched between the toner and the toner. An image forming method is used in which a toner image is formed on the dielectric by applying a voltage according to an image signal to a back electrode disposed opposite the developing bias electrode.

Function This invention is capable of uniformly charging a dielectric material with a polarity opposite to that of the toner, so that a bias voltage having a polarity opposite to that of the toner applied to a developing bias electrode which also serves as a toner carrier is applied to the back electrode. By applying an appropriate voltage according to the image signal, the toner is ejected by the electric field generated between the developing bias electrode and the back electrode, and a toner image corresponding to the image is formed on the dielectric material. , the effect of strengthening the adhesive force between the toner and the dielectric because the flying toner and the dielectric are combined with static electricity due to the charge of opposite polarity to the toner uniformly charged on the dielectric; , Since a bias voltage of opposite polarity to the toner is always applied to the developing bias electrode, the toner is attracted to the developing bias electrode by one electrostatic force,
It can be expected to have the effect of preventing toner from scattering during non-development.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the present invention. (
2) is a polyethylene sheet as a dielectric sheet, which is moved at a predetermined speed in the direction of arrow a by a driving device (not shown). (5) is the recording paper on which the toner image is transferred and recorded, and plain paper can be used. (6) transfers the toner image on the dielectric (2) to the recording paper (
5) It is a transfer device that transfers onto the surface. (1) is a charger that applies a charge uniformly to one side of the dielectric. (8) is a developing bias electrode that also serves as a toner carrier, and (7) is a bias power source that applies a developing bias voltage vb to the developing bias electrode (8). (3) is arranged to sandwich the dielectric sheet (2) and face the developing bias electrode (8), and is configured to apply an appropriate image signal voltage Vp according to the image signal (4).
This is a back electrode that applies a toner image to form a toner image on the dielectric sheet (2).

The toner (10) used in the developing device (9) is
In this example, it is a positively charged non-magnetic-component toner.

(11) is a cleaner for removing toner remaining on the dielectric material after the toner image is transferred.

The image forming method in this embodiment will be described in detail below with reference to FIG.

First, the dielectric sheet (2) is uniformly charged to a polarity opposite to that of the toner using the charger (1). In this embodiment, since a positively charging toner was used, charging was performed so that the surface potential Vo=-500V was achieved for one month. At this time, V is applied to the developing bias electrode (8) so that the toner can be attracted toward the developing bias electrode by electrostatic force during non-development.

A very low voltage must be applied, and this embodiment (3)
When an image signal (4) indicating that no development is performed is input, in this embodiment, the image signal voltage Vp applied to the back electrode (3) is set to Vp==OV. At this time, an electric field is generated in the direction from the back electrode (3) to the development bias electrode (8), so the positively charged toner on the development bias electrode (8) does not fly to the dielectric sheet (2), and development is not carried out. Not done. On the other hand, when an image signal (4) indicating that development is to be performed is input, in this embodiment, the image signal voltage Vp<ip> applied to the back electrode (3) is set to -300V. At this time, from the developing bias electrode (8) to the back electrode (3
) Since an electric field is generated in the direction, the developing bias electrode (8)
The positively charged toner on the top flies onto the dielectric sheet (2), and is electrostatically bonded by the negative charge (12) applied to the dielectric sheet (2) by the charger (1), resulting in development. It will be done. Dielectric sheet (2
), the voltage vb applied to the developing bias electrode (8), and the image signal voltage Vp applied to the back electrode are 1 Vol (lVb-vp+ for non-development, 1 Vol for developing) lVb-Vpl O conditions. need to be met.

When a toner image is formed by the above method, there is no toner scattering from the toner carrier during non-development, and the developed toner image is stable due to electrostatic force.

The toner image formed on the dielectric sheet (2) is transferred to a recording paper (5) by a transfer device (6), and the recording paper (5) is conveyed to a fixing device (not shown) where it is fixed. Also, the toner remaining on the dielectric sheet (2) can be removed using a cleaner (1).
1) There is no need to remove any remaining charge if the charger (1) is a scorotron charger that keeps the potential charged on the dielectric constant at all times. However, for example, a conductive roller may be pressed against the dielectric sheet (2) to eliminate static electricity. The dielectric sheet (2) that has gone through the steps described above is charged again by the charger (1) and is ready for the next development.

Effects of the Invention As described above, if this invention is used, when a toner image corresponding to the image is directly formed on a dielectric material using toner without forming a latent image in advance, The toner image is stabilized by electrostatic force - the toner adhering to the dielectric carrier does not scatter and cause image smearing.
Furthermore, it has the effect of preventing toner scattering during non-development, and making it possible to obtain good images without so-called toner fog.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining image formation by a conventional method. FIG. 2 is a block diagram of an apparatus according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram for explaining an image forming method in this embodiment. 1: Charger 2: Dielectric sheet 3: Back electrode 4: Image signal 7: Developing bias power source 8: Developing bias electrode 10: Toner applicant Minolta Camera Co., Ltd. Figure 3

Claims (1)

[Claims] 1. A method of forming a toner image corresponding to the image directly on a dielectric material using toner without forming a latent image in advance, in which the dielectric material is uniformly charged to the opposite polarity to the toner, and the toner is A bias voltage having a polarity opposite to that of the toner is applied to a developing bias electrode which also serves as a carrier, and a back electrode disposed opposite to the developing bias electrode with the dielectric material in between is applied with a bias voltage having a polarity opposite to that of the toner.
An image forming method in which a toner image is formed on the dielectric by applying a voltage according to an image signal.