JPH0347505B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording device, and more particularly to a recording device that directly controls the adhesion of a developer to an image receptor in response to an image-shaped electrical signal to form an image.

Conventionally, as an image forming method in which a developer is directly attached to a recording member as an image receptor using an electric signal,
There is a method known as the contrastography method, in which a liquid developer is placed on a recording member and the toner in the developer is adhered to the recording member using a needle electrode. However, since a liquid developer is actually used, it is inevitable that the liquid will seep into the recording member, making it impractical.

The object of the present invention is based on a new image forming principle that eliminates the drawbacks of the above-mentioned conventional examples, and makes it possible to form a good image by preventing the developer from facing the image receptor in areas other than the image forming area. It is meant to be.

To achieve the above object, the present invention provides a magnetic developer reservoir member in which apertures are formed in a magnetic material in a slit shape or in rows independently, and a magnetic field is formed across the apertures; A means for supplying a developer to the aperture, an image receptor disposed close to the aperture in a non-contact state, and an image receptor disposed on the opposite side of the developer reservoir member. A voltage is applied between the electrode and the developer reservoir member.

The above configuration allows the image receptor to form a recorded image without contacting the developer.

The present invention will be described in more detail below with reference to one example.

FIG. 1 is a cross-sectional view of an apparatus showing an embodiment of the present invention. In the figure, a conveying member 1, which is a supplying member for a powder developing agent (hereinafter referred to as toner), is formed in a cylindrical shape from a non-magnetic material. It has a fixed or rotatable magnet 2 therein for attracting the magnetic toner and aiding its conveyance. A toner layer of a constant thickness is formed on this toner conveying member 1 by a fixed blade 3. The magnetic bodies 4 and 5 constitute a toner reservoir member,
The opposite slit 6 formed of a magnetic material is placed in contact with or close to the toner layer formed by the blade 3. The magnetic flux generated by the magnet 2 is concentrated within the magnetic electrodes 4 and 5 that are closest to the magnetic poles. As a result, the strength of the magnetic field and the amount of change in the magnetic field increase in the region of the slit 6, and the magnetic toner on the conveying member receives a force that moves into the slit 6 and is confined within the slit.

On the other hand, the recording member 7 is brought into contact with the fixed electrode 8 and is fed in the direction of the arrow in the vicinity of the slit 6 filled with toner. When a signal voltage 9 is applied between the electrode 8 and one electrode 4 forming the slit 6,
Due to the electric field between the electrodes 4 and 8, the toner present in the slit 6 is transferred to the recording member 7, and a toner image is formed on this recording member. To form an image, at least one of the electrodes 8 and 4 must correspond to a pixel, and when the electrodes are usually fixed, they are in the form of a multi-needle electrode, and a voltage is applied to each electrode. voltage can be applied. Therefore,
Actually, FIG. 1 is a cross section of one pixel portion, and a plurality of image forming portions shown in FIG. 1 exist over the entire width of the recording member.

Since the above-described toner transfer requires the application of a voltage of a certain level or more, this can be used to simplify the drive circuit that distributes and selectively applies the image signal to each electrode. This is a method known from electrostatic recording devices.
For example, if the electrode 4 is a multi-needle electrode, the multi-needle electrode group is divided into several blocks, and the multi-needle electrodes with corresponding numbers are connected to each other, and the lead wires to the outside are for one block or two blocks. number of electrodes. The opposing electrodes 8 are divided corresponding to the blocks, and conditions are set such that the toner is transferred from the slit 6 to the recording member 7 only when a voltage is applied to both the electrodes 4 and 8 at the same time. In this case, if the toner is positively charged,
A voltage of positive polarity is applied to the electrode 4, while a voltage of negative polarity is applied to the electrode 8 according to the image signal.

When a conductive toner is used in the apparatus having the above structure, a matrix as described above can be set between the electrodes 4 and 5 as shown in FIG. Multi-needle electrode 10
The control electrode 11 is made by etching a bond of a magnetic thin film such as permalloy and a resin film such as polyimide. Since the toner is conductive, the potential of the toner held between the multi-needle electrode 10 and the control electrode 11 by the magnetic field has a value approximately halfway between the potentials of both electrodes at the center thereof. Therefore, if you choose a voltage that will not transfer the toner to the recording member at half the applied voltage, the toner will not transfer because only about half the voltage is applied to the part where voltage is applied only to one side of the electrode. Only when voltage is applied to both will the toner be transferred and the objective achieved.

An example of image forming conditions in the apparatus shown in FIG. 1 is shown below. Electrode 4 is made by bonding 50 micron thick permalloy and 25 micron thick polyimide film.
A multi-needle electrode was formed by etching with a pitch of 125 microns. The electrode 5 facing this electrode and forming a gap is made of permalloy with a thickness of 50 microns, the end is insulated with thermosetting resin, and the slit 6 is 150 microns thick.
It was arranged so that it was micron. The distance between the slit 6 and the toner conveying member 1 is 1 mm, and the thickness of the toner layer made of conductive toner is approximately 1 mm.
The magnet 2 is fixed and each member is arranged so that the slit 6 is located between the two magnetic poles.

The recording member 7, which receives the transferred toner, is made of high-quality paper and is moved at a distance of 300 microns from the slit surface. At this time, the voltage to electrode 8 is always +
A voltage of 400 V was applied, and a pulse voltage of -500 V was selectively applied to the multi-needle electrode 4 for a duration of 10 microseconds, thereby recording an image of toner on the recording member.

In the embodiment described above, the magnetic field within the slit 6 was formed by the magnetic poles of the magnets in the toner transport member, but it may also be formed by forming the electrodes 4 and 5 themselves with magnets, or by using another external magnet. good. The magnetic electrode forming the slit is not limited to a soft magnetic material, but a permanent magnetic material can also be used, and the electrode on one side of the slit can also be changed to a non-magnetic material.

According to the present invention, since an image can be formed without contacting the image receptor with the developer, the image receptor is not smeared with the developer or the fogging phenomenon occurs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a device showing an embodiment of the present invention;
FIG. 2 shows a plan view of an electrode constituting the developer reservoir member of the apparatus shown in FIG. In the figure, 1 is a developer supplying means, 4 and 5 are electrodes constituting a developer reservoir member, and 7 is an image receptor.

Claims (1)

[Scope of Claims] 1. A magnetic developer reservoir member in which slit-like or independently arranged apertures are formed in a magnetic material, and a magnetic field is generated across the apertures; A means for supplying a developer to the hole, an image receptor disposed close to the aperture in a non-contact state, and an electrode disposed on the opposite side of the image receptor from the developer reservoir member. An image recording device that applies a voltage between the electrode and the developer reservoir member.