JPH0222682A - Recording method - Google Patents

Abstract

PURPOSE:To perform satisfactory transfer by providing a magnetic means retaining magnetic toner between an electrode and the surface of an image carrier and impressing electric bias with an alternating electric field to the electrode during developing. CONSTITUTION:A recording electrode 3 is arranged near to the surface of the image carrier 1 so as to be able to cover recording width in a longitudinal direction. A magnet 4 is arranged on the reverse side of the image carrier 1, relatively near to the recording electrode 3, so as to be magnetically connected with the developing part thereof. The magnetic toner retained on the tip of the recording electrode 3 is formed into a toner chain 5 along lines of magnetic force between the recording electrode and the surface of the image carrier 1. At this time, the electric bias with an AC component superposed on a DC component is impressed on the recording electrode 3. As a result, a pulse-like developing electric field is formed in an image part, and electric charge is injected in the toner chain 5 by each pulse transiently. Satisfactory developing can be thereby performed, even when insulating magnetic toner is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of visualizing an electrostatic image formed on the surface of an image carrier such as a photoreceptor or dielectric material using a magnetic toner.

[Prior art]

Methods for visualizing the electrostatic charge image formed on the surface of the image carrier using the powder toner 1 include a method using a so-called two-component developer in which a magnetic carrier and a non-magnetic toner are mixed and stirred; - component It is roughly divided into methods using magnetic toner as a developer. In either of these methods, the powder developer is magnetically held on the surface of a non-magnetic cylindrical sleeve having a multi-polar magnet inside, and the powder developer is held magnetically on the surface of a non-magnetic cylindrical sleeve having a multi-polar magnet inside. conveyed along the sleeve surface,
The developing step is generally carried out by rubbing the surface of the carrier.

In addition, as a method that does not use the above-mentioned non-magnetic sleeve, Japanese Patent Publication No. 55-30228 and Japanese Patent Application Laid-Open No. 58-1982
Japanese Patent Application No. 50557 proposes a method or apparatus in which an image signal is applied to a multi-needle electrode to directly cause magnetic toner to adhere to the surface of a dielectric material.

[Problems to be solved by the present invention]

In the method using a two-layer developer, the toner is frictionally charged with the carrier and charged to a predetermined magnetic property, and while it has good stability for development and transfer, periodic father replacement occurs with respect to the magnetic carrier, which gradually deteriorates. There are restrictions on what is required and the ratio of toner to magnetic carrier, and there are complications such as the need to control the so-called toner l# degree. On the other hand, the one-component magnetic toner type is less complicated than the two-component type described above, but in order to ensure transfer performance, when using an insulating magnetic toner or a toner with a load t% property, toner agglomeration may occur on the sleeve. It has the disadvantage of easily occurring. In addition, in both methods, since the developer is transported at high speed, toner scattering is likely to occur due to centrifugal force, etc., and the inside of the machine is likely to be contaminated.

Further, the conventional developing method described above is mechanically complex and requires driving means such as a non-magnetic sleeve and stirring, and cannot be said to be inexpensive in terms of cost.

On the other hand, in the method of directly forming an image by applying image signals to multi-needle electrodes, the distance between each electrode is narrow and large voltage cannot be applied, and the magnetic toner involved in development is not moving, which affects development. Charge! The electrical resistance of the magnetic toner used for very efficient injection is set fairly low. That is, a so-called conductive magnetic toner is used.

In this case, induced charges are injected from the electrode into the magnetic toner to be developed, forming an adhesion force with the dielectric surface. This method creates a problem when transferring the imaged magnetic toner onto paper. That is, as described above, since conductive magnetic toner is used, there are problems in that the transferred image is disturbed and the transfer efficiency is significantly reduced.

Therefore, an object of the present invention is to provide a recording method that can perform good transfer.

[Means for resolving gaps]

In order to solve the above-mentioned conventional problems, the recording method of the present invention is a method of visualizing an electrostatic charge image formed on the surface of an image carrier using magnetic toner. A plate-like electrode is disposed close to each other in the direction, and a magnetic means for holding magnetic toner is provided between the electrode and the surface of the image carrier, and an electric bias including an alternating current electric field is provided at least during development. is applied to the electrode.

〔Example〕

FIG. 1 shows an embodiment of the developing section according to the present invention. In the figure, an image carrier 1 is formed of a dielectric material such as alumite or polyester, or a photoreceptor, and is installed to be movable in the direction of the arrow X shown in the figure. Further, the support (conductor) 2 of the image carrier 1 is grounded. The recording pole 6 is arranged close to the front surface of the image carrier 1 so as to cover the recording width in the longitudinal direction. A magnet 4 is installed on the back side of the image carrier 1 and is placed relatively close to the developing section of the recording electrode 3 so as to be magnetically coupled thereto. Therefore, it is desirable that the developing section of the recording electrode B has an acute cross-sectional shape so that the lines of magnetic force are concentrated, and at least the developing section at the tip thereof is formed of a magnetic material, or the developing section near the tip is made of a magnetic material. It is desirable that a magnetic material is disposed. When such a magnetic circuit is formed, the magnetic toner held at the tip of the recording electrode 6 forms a toner chain 5 along the lines of magnetic force between it and the surface of the image carrier 1.

On the other hand, the image carrier 1, which has an electrostatic charge image formed on its surface by a predetermined means, moves in the direction of the arrow X shown in the figure, and the electrostatic charge image comes into contact with the toner chain 5. In the present invention, the electrical resistance of the magnetic toner forming the toner chain 5 is set relatively high so that the image is not disturbed during the transfer process.

That is, since insulating magnetic toner is used, it is extremely difficult to inject charges contributing to development into the toner chain 5, which does not move turbulently, using only a direct current electric bias. Therefore, in the present invention, instead of stirring the magnetic toner in the mechanical developing section, electrical turbulence, that is, an electrical bias in which an alternating current component is superimposed on a direct current component is applied to the recording electrode B. As a result, a pulsed developing electric field is formed in the image area, and charges are transiently injected into the toner chain 5 during each pulse, resulting in good development even when insulating magnetic toner is used. 0 FIG. 2 shows another embodiment of the present invention. Each essential element is designated by the same number as in FIG.

The difference between FIG. 2 and FIG. 1 is the position of the magnet 4, which is placed in contact with or close to the recording electrode 3. In this case as well, the lines of magnetic force can be concentrated at the tip of the recording electrode 6, and therefore the recording electrode 6 can be
A toner chain 5 can be formed between the tip and the surface of the image carrier 1.

In the present invention, an insulating magnetic toner is used as described above, but the development performance can be further improved by using a so-called charged type magnetic toner that has a strong charge-accepting ability or charge-holding ability in one direction. I can do it.

The optimum voltage and frequency applied to the recording electrode 3 for forming an alternating electric field in the developing section vary depending on the moving speed of the image carrier 1, but the respective voltages are 600 V to 600 V in peak-to-beat value. 2400V, the frequency is set to such an extent that stripes do not appear on the image, but 200 [1
It is desirable that the range is from z to 2000111z.

As described above, in the present invention, the B toner chain 5 is formed by the lines of magnetic force concentrated at the tip of the recording electrode 6, and the electric charge that contributes to development is supplied to it by the alternating current electric field.
The formed toner chain 5 is strengthened by the recording electrode 6.
In order to maintain the charge at the tip or to inject charges more efficiently, it is desirable to set the gap between the tip of the recording section 3 and the surface of the image carrier 1 as small as possible, and the gap is preferably 0.1 m to 0.0 m. 5. , is set to a degree.

Further, in the recording method according to the present invention, by selecting the magnitude of the DC component applied to the recording tm3 or the charge retention polarity of the magnetic toner used, both regular development and reverse development are possible. For example, in the case of regular development, the recording electrode 3
The magnitude of the DC component applied to the image carrier 1 is set to be lower than the potential of the electrostatic image formed on the surface of the image carrier 1, so that a larger developing electric field acts on the area where the electrostatic charges are held. If a charged magnetic toner is used in this case, it is desirable that the charged polarity of the magnetic toner be opposite to the electrical polarity of the electrostatic image. On the other hand, in the case of reversal development, the magnitude of the DC component applied to the recording electrode 3 is
It is set to be approximately the same as the magnitude of the potential of the electrostatic charge image formed on the surface.

That is, the setting is made so that a stronger developing electric field is formed in areas with less electrostatic charge on the six surfaces of the image carrier 1.

If a charged magnetic toner is used in this case, it is desirable that the charged polarity of the magnetic toner be the same as the electrical polarity of the electrostatic charge image.

〔Effect of the invention〕

As described above, according to the present invention, the following effects can be obtained.

(2) Since no large mechanical force is applied to the developing section, agglomeration is unlikely to occur even when - component magnetic toner is used alone.

(2) By using the AC bias means, it is possible to inject charges contributing to development into the toner chain of insulating magnetic toner that does not move, and as a result, a good developed image can be obtained.

(2) Since the obtained developed image uses insulating magnetic toner, the image is not disturbed during transfer.

(2) When forming a developing device, a means for conveying the magnetic toner to the developing section is required, but since there are fewer mechanically operating parts, a low-cost and highly reliable recording device can be constructed.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing the recording method of the present invention. 1: Image carrier 2: Conductive support 3: Recording electrode 4: Magnet No. figure No. figure

Claims (5)

[Claims] (1) A method of visualizing an electrostatic image formed on the surface of an image carrier using magnetic toner, in which plate-shaped electrodes are disposed close to each other along the longitudinal direction of the image carrier, and A recording method comprising a magnetic means for holding magnetic toner between the electrode and the surface of the image carrier, and applying an electric bias including an alternating current electric field to the electrode at least during development. (2) The recording method according to claim (1), wherein the electrode is a magnetic material. (3) The magnetic means is a magnet arranged on the back side of the image carrier, and is formed by arranging it so as to magnetically couple with the tip of the electrode. ).The recording method described in ). (4) The recording method according to claim 1, wherein the magnetic field generating means is formed by a magnet placed close to or in contact with the electrode. (5) The recording method according to claim (1), wherein the magnetic toner is insulating.