JPS604076A - Image recorder - Google Patents

Abstract

PURPOSE:To contrive to enhance toner density of an image, by a method wherein a recording current fed from a recording power source is made to be constant, and variations in the earing condition of a toner on a recording electrode are prevented from adversely affecting the variation of resistance. CONSTITUTION:Resistors 10 are provided between end parts of the recording electrodes 4 and a signal electrode 9. The resistors 10 are so provided as to correspond to each of the recording electrodes 4, and the electrical resistance thereof is set to a high value approximately equal to that of a conductive magnetic toner provided on the electrodes 4. In this construction, even when the earing condition of the toner provided on the recording electrode 4 is varied and the positions of magnetic poles of a magnet roller are varied to vary the electrical resistance, a substantially constant current is supplied from the electrode 4 to the toner provided thereon, so that a favorable image with constant density can be obtained. Instead of the resistor 10, a constant-current circuit 13 constituted of a transistor 11, a resistor 12 or the like may be provided between the signal electrode 9 and each of the recording electrodes 4, or a resin layer 14 having a high electrical resistance may be provided at a tip part of the recording electrode 4 provided on a non-magnetic toner feeding member 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image recording device, particularly an image recording device that forms an image by directly attaching a conductive magnetic developer (hereinafter abbreviated as toner) to a recording medium in response to an image electric signal. Regarding.

A conventional device of this type is U.S. Patent No. 38168.
It is disclosed in No. 40. A very general outline of this conventional device will be explained with reference to FIG. In Figure 1, is l the toner container? 3 is a toner conveying member made of a non-magnetic cylinder made of aluminum or stainless steel, and 3 is a magnetic roller that rotates in the direction of arrow A inside this toner conveying member l. Magnetic poles of different polarity are alternately magnetized in the gap. Reference numeral 4 denotes a large number of recording electrodes, each of which is arranged independently and electrically insulated in a part of the toner conveying member 1 in the axial direction of the member 1, and is made of, for example, permalloy, nickel, iron, etc. ing. Reference numeral 5 denotes a recording medium that is conveyed in the direction of the arrow while facing the electrode member 4, and has an insulating layer 5b formed on the surface of a conductive substrate 5a. It is also possible to use recording paper. Reference numeral 6 denotes a conductive back electrode disposed opposite to the electrode member 4 so as to sandwich the recording medium 5 therebetween;
is in contact with the surface of the conductive substrate 5a.

The conventional image recording device has the above configuration, and the magnet 3
is driven in the direction of arrow A, and the recording medium 5 is driven in the direction of arrow B by a drive source (not shown).

The toner T in the container 2 is affected by the magnetic field of the magnet roller 3.
While being held on the toner conveying member l, the toner is conveyed in a fixed amount in a direction A' opposite to the direction of rotation of the magnet 3. Toner T in container 2
is regulated into a uniform thin layer by a doctor blade 7 provided at the outlet of the container, and when the recording electrode 4 reaches the recording position 8 where the recording electrode 4 and the back electrode 6 face each other, the recording electrode 4 is
When a voltage corresponding to the image is applied to !・Na T1
Charge is injected into the recording medium 5 through the recording medium 5, and due to the force of this charge, the toner T1 reliably forms an image on the insulating layer 5b of the recording medium 5.

The toner T2 that has moved onto the insulating layer 5b may be fixed on the recording medium by a fixing means such as heating or pressure (not shown), or may be transferred to another member for use. The above method has problems when trying to obtain high resolution image quality.

The state of the toner ears formed on the recording electrode 4 changes due to the magnetic force of the rotating magnet roller, so the density of the recorded image formed depends on the state of the ears when an image signal is applied, that is, the position of the magnetic pole. Changes may occur. The main reason for this is thought to be that the electricity 41 (resistance) between the recording electrode and the recording medium changes depending on the above-mentioned toner spike state.

To improve this point, a method has been proposed in which the position of the magnetic pole is detected and an image signal is provided only when the magnetic pole is at a desired position. However, the rotational speed of the magnet is mechanically limited and not only does it not lend itself to higher speeds, but it also requires means for detecting the magnetic pole position, as well as an electric circuit to synchronize the image signal with the magnetic pole detection signal. However, it had the disadvantage of becoming larger and more complex.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus which eliminates the drawbacks of the above-mentioned conventional examples and can always stably supply a good image regardless of the state of toner spikes on a recording electrode.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.
264vLQF14rflJx:21, r@l[i9.
! FQ-a+t*' Indicates constituent members with the same function.

In FIG. 2, 1 is a toner conveying member having a rotating magnet 3 disposed therein, and 4 is a group of magnetic recording electrodes that are independent of each other and each electrically insulated. A resistor 10 is provided between the ends of these recording electrodes 4 and the signal power source 9 to constitute the present invention. This resistor 10 is provided so as to correspond to each of the recording electrodes 4, and is approximately the same as the electrical resistance value of the conductive magnetic toner formed on the recording electrode.
or higher. With the above configuration, even if the position of the magnetic pole of the magnetic roller changes and the resistance value changes, a nearly constant current is always applied from the recording electrode 4 to the top of the recording electrode 4. of the toner, and a good image with constant toner density can be obtained.

By the way, in the above example, the recording electrode 4 is formed by etching a magnetic material onto an insulating film 15 such as a polyimide film, or by etching a copper foil and then plating a magnetic material such as 29 Kel or permalloy thereon. Good too. Also,
Alternatively, thin permalloy wires may be arranged in parallel and fixed with epoxy resin or the like. In the experimental device, a polyimide film etched with nickel was used as a recording electrode. In addition, the particle size of the toner used can be about 5 to 100 microns, but in this experiment, VQC imaging powder TYPE 355 (three-
(manufactured by M Co., Ltd.), and the particle size of these particles was more than ten microns. On the other hand, the non-magnetic cylinder used was a cylinder made of stainless steel with an outer diameter of 32+ am, and the recording medium used was an insulating layer formed on aluminum and alumite processed to a thickness of 0.5 microns. The distance between this recording medium and the tip of the recording electrode 4 was maintained at 100 microns. The recording electrodes actually used were 10 nickel needles with a diameter of 60 microns.
210 mm parallel to each other with a recording width of 210 mm at intervals of 0 microns.
It was adhered to the stainless steel cylinder using a 0-line epoxy adhesive. Each of the recording electrodes 4 was connected to a signal electrode source via a 500 megohm resistor. 5 under the above conditions
When a signal voltage of 0 V was applied to each signal electrode 4 to produce an image, a clear image with no density difference was obtained.

FIG. 3 shows another embodiment of the present invention, in which a constant current circuit 13 is constructed of a transistor 11, a resistor 12, etc. between the signal power source 9 and the recording electrode 4 instead of the resistor lO of the above embodiment.
This circuit is also connected to each of the recording electrodes 4 in correspondence with each other. In addition, when implementing the electric circuit as described above, it is possible to use a constant current printed circuit, or it is also possible to arrange a transistor array connected to the recording electrode needle made by the above-mentioned etching on the sleeve. It is.

FIG. 4 shows still another embodiment of the present invention, in which an electrically high resistance resin layer 14 is provided at the tip of the recording electrode 4 provided on the non-magnetic toner transport member l. . The resistance value of the resin layer in this case may be set in the same manner as in the case of FIG. 2 above.

In this way, the present invention makes it possible to obtain a good image without being adversely affected by the change in resistance due to changes in the state of toner standing on the recording electrode by making the electric signal from the recording power supply a constant current.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram for explaining the operating principle of an image forming apparatus to which the present invention is applied, FIG. 2 is an explanatory diagram showing one embodiment of the present invention, and FIG. 3 is an explanatory diagram showing another embodiment of the present invention. FIG. 4 is a partial cross-sectional view of a recording electrode section showing another embodiment of an electrical circuit diagram for implementing a certain current constant. In the figure, 1 is a toner conveying member, 3 is a magnet roller, and 4 is a toner conveying member.
1 is a signal electrode, 5 is a recording medium, 9 is a signal power source, 10 is a resistor, and 14 is a resistive layer made of a resin layer.

Claims (1)

[Claims] (1) a developer conveying member that conveys conductive magnetic toner;
a moving magnet provided on the back side of the conveying member; an electrically insulated electrode on the developer conveying member; a recording medium facing the recording electrode and moving; An image recording apparatus comprising: a signal power supply for applying an image signal voltage between a medium and a recording electrode; and means for keeping a recording current from the signal power supply substantially constant.