JPS6186764A - image recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image recording device, and in particular to an image recording device that directly controls toner to adhere to a recording medium using an electric signal corresponding to an image. The present invention relates to an image recording device that obtains images.

[Background of the invention]

An example of a conventional image recording device of this type is U.S. Pat. No. 3.91.
No. 4.771.

An example of this conventional image recording apparatus will be explained with reference to the cross-sectional view shown in FIG. Move in the direction of the arrow. As the recording medium 1, it is also possible to use a generally commercially available electrostatic recording paper. Reference numeral 4 denotes a conductive roller-shaped back electrode, which is in contact with the conductive material 2 of the recording medium 1 that is fed in the direction of the arrow. Reference numeral 5 denotes electrode members for applying an image signal voltage, which are fixed in large numbers in a row on a cylinder 6 described below, insulated from each other. This electrode member 5 is made of a conductive magnetic material such as /4-malloy, 2-Kel, iron, etc., and its tip is bent to form an electrode protrusion. Reference numeral 6 denotes a non-magnetic stationary cylinder serving as a means for transporting the toner to a recording position, and is immersed in one-component conductive magnetic toner 8 in a toner container 7 . cylinder 6
and the electrode member 5 are electrically insulated. A rotating magnet 9 is provided inside the toner conveying member 6, which is a non-magnetic cylinder, and this magnet 9 is magnetized with magnetic poles of different polarity alternately. Due to the action of the magnet 9, the toner 8 is transported on the toner transport member 6 in a direction opposite to the rotational direction A of the magnet 9.

The transported toner is turned into a uniform thin layer by the action of the doctor blade 100 and reaches the recording position 11. Here, the toner adheres to the recording medium 1 and forms an image when a signal voltage corresponding to the image is applied from the signal power source 12 between the electrode member 5 and the back electrode (therefore, the recording medium 1 in contact with it). be done. The toner image deposited on the recording medium 1 is fixed by means such as heating or pressure.

FIG. 3 shows another example of this type of image recording apparatus, which is described in detail in Japanese Patent Application Laid-Open No. 55-127578. The same numbers as in FIG. 1 indicate elements that perform the same functions. In this example, the recording medium 1 is cylindrical and rotates in the direction of arrow A'. The conductive magnetic electrode 5 is opposed to the recording medium 1 with a slight distance therebetween, and is penetrated by the magnetic flux of the magnet 9 surrounding it. 1
When the non-magnetic toner 16 rotates in the direction of arrow C, the conductive magnetic toner 8 moves from the toner container 7 in the direction of the arrow on the application roller 13 and is conveyed to the recording medium 1. in this case,
A voltage is applied between the power source 14 and the recording medium 1 and the toner application roller 13, so that the toner 8 is applied onto the recording medium 1 in a thin layer.

When the applied toner 8 reaches the recording electrode 5, the toner 8 forms a toner chain on the tip of the recording electrode 5, and the charge injected by the coating roller escapes through the toner chain, so that the recording medium 1 and the toner 8, no adhesive force will work between it and 8. On the other hand, when an image signal voltage is applied between the recording medium 1 and the recording electrode 5 compared to the signal power source 12, electric charges are generated on the recording medium 1 through the toner chains, as shown in FIG. A force is exerted to adhere the recording medium 1 to the recording medium 1. Next, the toner 8 that has been charged in the image pattern is removed by a toner removing device 15 (for example, means using a magnetic field or air suction) to the extent that it is not disturbed, and the toner 8 that has no adhesion is removed from the recording medium. A visible image corresponding to the image signal appears on 1.

By the way, in the images obtained by these conventional image recording devices, the magnetic field generated by the magnet 9 spreads near the recording medium 1, so when the toner 8 on the recording electrode 5 comes into contact with the surface of the recording medium 1, it spreads along this magnetic field. Therefore, the width of the recording electrode 5 becomes wider, and the recorded image obtained becomes blurred. As a solution to this problem, Japanese Patent Application Laid-open No. 57-173854 and Japanese Patent Laid-Open No. 57-1976
As shown in Fig. 2, a method has been proposed in which a back electrode made of a magnetic material is used on the opposite side of the recording medium 1 at a position facing the recording electrode 5, and Fig. 4 illustrates this method. Reference numeral 17 denotes a back electrode made of a ferromagnetic material such as iron or nickel, and the rest of the structure is the same as that of the conventional device described above. The width of the back electrode 17 (the length in the left-right direction in the figure) extends over the width of the magnet 9. In this configuration, the magnetic field generated by the magnet 9 extends substantially perpendicularly to the recording medium 1 through the recording electrode 5, so that a clear recorded image without dot diameter expansion can be obtained.

However, in this method, since the magnetic field generated by the magnet 9 is concentrated on the end face of the back electrode 17, the toner 8 tends to collect on the end face of the back electrode 17. The toner 8 accumulated on the end face of the electrode 17 is transferred as the recording medium 1 moves and contaminates the inside of the apparatus, which is undesirable. It reduces the spread of the magnetic field from the recording electrode to the recording medium, ensuring the clarity of recorded images, and prevents toner accumulation near the edges during recording, making it possible to obtain stable images over a long period of time. [Summary of the Invention] The present invention provides an image recording device of the type described above, in which a magnetic field applying means for applying a magnetic field between a recording electrode and a recording medium (the above-mentioned example) is provided. In other words, the feature is that a ferromagnetic material having a width wider than the width of the magnet 9) in the recording medium width direction is arranged on the opposite side of the recording medium, facing the recording electrode.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, in which the vicinity of the recording electrodes is viewed in the direction of the tangential plane of the recording medium. In this embodiment, the width of the back electrode 17 made of a magnetic material is made longer than the width of the magnet 9, so that the end face of the back electrode 17 is located outside the width of the recording medium 1. As a result, the magnetic field is not concentrated on the end face, the toner 8 does not accumulate, and even if the recording medium 1 moves, the toner 8 does not scatter into the apparatus. When applied to the image recording device shown in FIG. 2, the back electrode 17 may also serve as the back electrode 4 shown in the same figure, and when applied to the image recording device shown in FIG. 3, it faces the recording electrode group 5. It may be placed on the opposite side (inside) of the recording medium 1.

Figure 5 shows part of another type of image recording device.
This is an image recording device of FIG. 3 in which the recording medium is not cylindrical but belt-shaped, and a back electrode 17 made of a magnetic material that rotates at the same circumferential speed is arranged opposite to the recording electrode group 5). The operation is essentially the same as that of FIG.

Conventionally, in FIG. 5, the back electrode 17 using a magnetic material extends across the width of the magnet 9, and the toner 8 adheres to the end face due to magnetic flux concentration, and as the back electrode 17 rotates in the direction of arrow E. Since this toner 8 also moves together, more unnecessary toner 8 is carried than in the case shown in FIG. . However, according to the embodiment of the present invention, the width of the back electrode 17 in FIG. 5 is made wider than that of the magnet 9. This eliminates the aforementioned drawbacks. Furthermore, by making the linear velocity of the recording medium 1 and the back electrode 17 the same, there is no wear on the back electrode 17 due to the movement of the recording medium 1, and the distance between the recording electrode 5 and the recording medium 1 is always constant. distance is maintained,
A stable image can be obtained for a long time.In another embodiment, a ferromagnetic drum may be used as the back electrode 17, and the dielectric layer 3 may be coated on the upper surface of the drum.

A similar effect can also be obtained by providing a curved surface on the end surface of the back electrode 17 from the non-recording position.

〔Effect of the invention〕

As explained above, with a simple configuration in which the width of the back electrode made of magnetic material is made wider than the width of the magnet, it is possible to reduce toner stains inside the device and obtain stable images over a long period of time. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing one embodiment of the present invention, FIGS. 2 and 3 are schematic sectional views showing conventional examples of an image recording apparatus to which the present invention is applied, and FIG. FIG. 5, which shows the back electrode, is a partial sectional view of another type of image recording apparatus to which the present invention is applied. 1... Recording medium 4... Back electrode 5...
Electrode member 6... Toner conveying cylinder 8...
- Toner... 9... Magnet 10... Doctor blade 11... Recording position 12... Image signal voltage source 13... Application roller 14... Voltage source
15... Toner removal device 16... Rotating magnet
17... Back electrode Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] 1. A recording electrode group, a recording medium that is close to and moves relative to the recording electrode group, and means for supplying conductive magnetic toner into a gap between the recording electrode group and the recording medium. , an image recording apparatus comprising a magnetic field applying means for applying a magnetic field to the gap, and a means for applying an image recording voltage to selected electrodes of the recording electrode group according to an image pattern, the magnetic field applying means in the width direction of the recording medium; 1. An image recording device characterized in that a ferromagnetic material having a width wider than the width of the ferromagnetic material is disposed on the opposite side of the recording medium, facing the recording electrode group. 2. The image recording device according to claim 1, wherein the ferromagnetic material has an endless surface that moves at the same circumferential speed as the recording medium.