JPS6227389B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a recording medium between a recording electrode and a back electrode that are opposed to each other, and a magnetic field generated from a magnet that is opposed to the back electrode via the recording electrode. , relating to a recording device that performs recording on the recording medium by applying a voltage between the recording electrode and the back electrode in a state where a so-called toner chain is formed between the recording electrode and the recording medium. It is.

1 and 2 show a conventional recording device of this type used in facsimile machines and the like. A sleeve 1 is made of a non-ferromagnetic material and is fixed to the main body of the device (not shown).

A magnetic roll 2 having a plurality of S poles and N poles alternately formed on its outer peripheral surface is housed in the sleeve 1 so as to be rotatable coaxially with the sleeve 1. The magnetic roll 2 is rotated in the direction of arrow A in the figure by a drive device (not shown).

A hopper 3 is provided near the top of the sleeve 1, and a doctor 4 is provided below the bottom opening of the hopper 3. This doctor 4 is opposed to the outer peripheral surface of the sleeve 1 with a doctor gap 5 interposed therebetween.

The hopper 3 contains a so-called one-component toner 6 which is made by kneading a pigment, a ferromagnetic material, a conductivity modifier, a resin, etc. into fine powder.

At the lowest part of the sleeve 1, there are n pin-shaped recording electrodes E ₁ to _{E o} made of ferromagnetic material via a recording electrode holding part 7 made of an insulator such as epoxy resin.
is installed. Here, these recording electrodes E ₁ to _{E o} are arranged in a line at the same pitch on a straight line parallel to the axis of the sleeve 1. Further, the recording electrode holding section 7 is provided with slopes 8 and 9 on both sides extending from the outer circumferential surface of the sleeve 1 toward the lower end of each of the recording electrodes E ₁ to _{E o} .

Each of the recording electrodes E ₁ to _{E o} is connected to the positive electrode of a power source 10 via switching means S ₁ to S _o provided for each of the electrodes E ₁ to E _o , and the negative electrode of the power source 10 is connected to the ground. has been done. Further, the recording electrode E ₁ ~
A back electrode 11 is provided below E _o to face the electrodes E ₁ to _{E o} , and the back electrode 11 is grounded. Reference numeral 12 denotes a recording medium such as recording paper, which is conveyed in the direction of arrow C between the recording electrodes E ₁ to E _o and the back electrode 11 by a conveyance device (not shown).

In this device, the toner 6 in the hopper 3 is supplied from the bottom opening of the hopper 3 through the doctor gap 5 onto the outer peripheral surface of the sleeve 1. As the magnetic roll 2 is rotated in the direction of arrow A, the toner 6 supplied onto the outer circumferential surface of the sleeve 1 is moved over the outer circumferential surface of the sleeve 1 by arrow B in the opposite direction to arrow A.
The recording electrode holding section 7
It reaches the lower ends of the recording electrodes E ₁ to _{E o} through the slope 8 of the recording electrodes E 1 to E o.

Here, the outer peripheral surface of sleeve 1 and the recording electrode
Particles of toner 6 near E ₁ to _{E o} (hereinafter referred to as toner 6
(the particles are simply referred to as toner particles) are connected in a chain along the lines of magnetic force emanating from the magnetic poles of the magnetic roll 2, forming a so-called toner chain. Since the magnetic lines of force converge and pass through each of the recording electrodes E ₁ to _{E o} , toner chains T ₁ to _{T o} are formed on each of the recording electrodes E ₁ to _{E o} , respectively.

Now, in this state, the switching means S ₁
~S _o is turned on, recording electrode E ₁ ~ _{E o} and back electrode 1
When a recording voltage is applied between the toner chain T 1 and T ₁ , a positive charge passes through the recording electrodes E ₁ to _{E o}
~ _To is induced by the particle at the tip, while a negative charge is induced to the back electrode 11. Since the Coulomb force (attractive force) acting between the positive charge and the negative charge is more dominant than the attractive force of the magnetic lines of force, the toner chain
The toner particles at the leading edge of T ₁ to _{T o} move toward the recording medium 12 and adhere to the surface of the recording medium 12 . As a result, dots corresponding to each of the recording electrodes E ₁ to _{E o} are recorded on the recording medium 12 .

Therefore, by selectively applying a voltage between each of the recording electrodes E ₁ to E _o and the back electrode 11 by turning on and off each of the switching means S ₁ to S _o , a desired voltage can be applied to the recording medium 12. images can be recorded.

Further, the toner particles that have not migrated to the recording medium 12 climb up the slope 9 of the recording electrode holder, are again conveyed on the outer circumferential surface of the sleeve 1 in the direction of arrow B, and then pass through the doctor gap 5 and return to the recording electrode E. ₁ to _Eo .

Here, the reason why the recording electrodes E ₁ to _{E o} are made of a ferromagnetic material is that the lines of magnetic force emitted from the magnetic roll 2 are concentrated on each of the recording electrodes E _{1 to E o .} A toner chain T ₁ to T _o clearly corresponding to these recording electrodes is formed on the top, so that the recording dots clearly correspond to each recording electrode E ₁ to _{E o} , thereby producing a high quality recorded image. It's to get it.

However, in such a conventional recording device, the magnetic roll 2 is attached so that the diameter of the dots recorded by the recording electrodes E ₂ to E _o-1 other than the recording electrodes E ₁ and E _o at both ends is appropriate. By adjusting conditions such as the amount of magnetism, the size of the gap between each of the recording electrodes E ₁ to E _o and the recording medium 12, and the size of the doctor gap 5, recording is performed by the recording electrodes E ₁ and E _o at both ends. There was a drawback that the diameter of the dots was not larger than the appropriate diameter, which deteriorated the image quality.

The present invention has been made to solve the above-mentioned conventional drawbacks, and it is possible to make the recording dot diameters of the recording electrodes at both ends of the aligned recording electrodes equal to the recording dot diameters of the other recording electrodes, and to An object of the present invention is to provide a recording device that can obtain high-quality images.

The reason why the diameter of the recording dot becomes large due to the recording electrodes E ₁ and E _o at both ends as described above was previously unknown, but as a result of intensive research, the inventors have clarified the cause as follows.

That is, first, the inventor of the present invention
The thickness of toner chains T ₁ and T _o formed on E ₁ and E _o is higher than that of toner chains T ₂ to T o-1 formed on other recording electrodes E ₂ to _{E o -} 1. I found that it was higher than that. As a result, when the tips of the toner chains T ₂ to _{T o-1} are brought into contact with the recording medium 12 to the extent that the diameter of the recording dots formed by the recording electrodes E ₂ to _{E o-1} is appropriate, the toner chains at both ends
The tips of T ₁ and T _o are greatly crushed by the recording body 12, and this causes the electrodes E ₁ and T o at both ends to be crushed by the recording body 12.
While the recording dot diameter due to E _o becomes larger than the appropriate diameter, the tips of the toner chains T ₁ and T _o at both ends are adjusted to the extent that the recording dot diameter due to the electrodes E ₁ and E _o at both ends becomes appropriate. When you touch 12,
Since the other toner chains T ₂ to _{T o-1} either do not come into contact with the recording medium 12 at all or come into contact only slightly, recording can no longer be performed with the recording electrodes E ₂ to _{E o-1.} It turned out that only blurred recording dots could be obtained.

Also, as mentioned above, the toner chain at both ends
The reason why the heights of T ₁ and T _o are higher than the heights of the other toner chains T ₂ to _{T o-1} is considered as follows. That is, in normal use, as shown in FIG. 3a, each recording electrode E ₁ to _{E o} attracts toner particles in the range R ₁ to _{R o} ( Adjacent areas (hereinafter simply referred to as pull-in ranges) partially overlap with each other.

However, the retraction range R ₂ to R _o-1 overlaps with the retraction ranges R ₁ to _{R o} on both sides, but the retraction ranges R ₁ and _Ro at both ends overlap only with the retraction ranges R ₂ and R _o-1 , respectively. overlap. Therefore, the amount of toner particles drawn into the toner chains T ₁ and T _o at both ends is greater than the amount of toner particles drawn into the toner chains T ₁ and _{T o} at both ends.
Since the amount of toner particles drawn into _-1 is larger than the amount of toner particles drawn into
It is considered that T ₁ and T _o are higher than the other toner chains T ₂ to _{T o-1} .

Therefore, as shown in Figure 4a, each retraction range
The amount of magnetization of the magnetic roll 2 and the doctor gap 5 are adjusted so that the outer circumferences of R ₁ to R _o are in a state of circumscribing each other.
If the size etc. of the toner chains T 1 and T o at both ends can be precisely controlled, the heights of the toner chains T ₁ and T _o at both ends can be made equal to the heights of the other toner chains T ₂ to T _o-1 , as shown in Figure b. It will be done.

However, this is actually very difficult due to the configuration of the device.

Also, as shown in Fig. 5a, each retraction range R ₁ ~
Although it is possible to control the amount of magnetization of the magnetic roll 2 so that R _o are completely separated from each other, in this case, each of the recording electrodes E ₁ to
The amount of toner particles that E _o attracts from its surroundings decreases, and the toner chain T ₁ to _{T o} cannot be clearly formed, resulting in the inconvenience that a good quality image cannot be obtained.

The present invention has been made in view of these circumstances, and it is possible to make the heights of toner chains formed on all recording electrodes equal by providing dummy electrodes at both ends of a row of recording electrodes. be.

The present invention will be described in more detail below based on embodiments shown in the drawings.

In FIG. 6, dummy electrodes D ₀ and D _o+1 are attached to the sleeve (not shown) via the recording electrode holding section 7.
(Dn+1 is not shown) is on the extension of the row of recording electrodes E ₁ to E _o , and the distance from the recording electrodes E ₁ and E _o at both ends is the same as the pitch between each recording electrode E ₁ to E _o. It is installed as such. The dummy electrodes D ₀ and D _o+1 are made of the same material, shape, and size as the recording electrodes E ₁ to E _o , and are grounded directly or through a suitable impedance. The other configurations are the same as those of the conventional device.

_In this _{device ,} as _shown in _{FIG .} If you adjust the amount of magnetization of the magnetic rolls and the doctor gap so that they partially overlap each other,
Due to the above-mentioned reason, dummy electrodes are used as shown in figure b.
Toner chain T ₀ to T _o formed on D ₀ , D _o+1
+1 is higher than the height of the toner chains T ₁ to _{T o+1} formed on the recording electrodes E ₁ to _{E o} . However, since the recording electrodes are not applied to the dummy electrodes D ₀ and Dn, the toner chains T ₀ and T _o+1 do not transfer to the recording medium.
The recorded image does not deteriorate due to an increase in T ₀ to T _o+1 .

On the other hand, since the heights of the toner chains T ₁ -T _o formed on all the recording electrodes E ₁ -E _o are the same, the recording dot diameters of all the recording electrodes E ₁ -E _o are made the same, and A good image can be obtained over the entire screen.

Note that if the dummy electrodes D ₀ and D _o+1 are not grounded and left open, the adjacent recording electrodes
When a recording voltage is applied to E ₁ and E _o , an induced voltage is generated on the dummy electrodes D ₀ and D _o+1 , and recording is also performed on the dummy electrodes D ₀ and D _o+1 due to this induced voltage. However, if the dummy electrodes D ₀ and D _o+1 are grounded directly or through an appropriate impedance as in this embodiment, such a risk can be eliminated.

In addition, in the conventional apparatus, not only the toner chains T ₁ and T _o but also the toner chains in the vicinity may be higher than the other toner chains on the center side. This corresponds to each recording electrode E ₁ to _{E o}
This is thought to be due to the magnetic influence not only from the adjacent recording electrodes but also from other nearby recording voltages. Therefore, if the number of dummy electrodes provided at both ends of the row of recording electrodes E ₁ to E _o is not only one each as in the above embodiment, but a plurality of each, all the recording electrodes can be more completely covered. _E1 ～
The heights of the toner chains T ₁ to _{T o} formed on E _o can be made uniform. In addition, in this case as well,
Each dummy electrode has the same material, shape, and size as the recording electrodes E ₁ to _{E o} , and is arranged at the same pitch between each recording electrode E ₁ to _{E o} on the extension of the row of recording electrodes E ₁ to E _o . Needless to say, it is preferable to arrange them in pitches.

In the present invention, the mechanism for conveying the developer around the recording electrode is not limited to the example shown in FIG. 1, but may be of a type in which, for example, the magnetic roll is fixed and the sleeve is rotated. , or may be of a type that does not use a sleeve.

As described above, in the recording device according to the present invention, by providing dummy electrodes made of ferromagnetic material at both ends of a row of recording electrodes made of ferromagnetic material, the diameter of the recording dots produced by the recording electrodes on both ends is different from that of other recording electrodes. This provides an excellent effect of preventing the diameter of the recording dots from becoming larger than the diameter of the recording dots formed by the electrodes, and allowing a good recorded image to be obtained over the entire screen.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a conventional recording device, FIG. 2 is an enlarged perspective view showing the vicinity of the recording electrodes of the conventional device, and FIG. FIG. 3b is a sectional view showing the state of the toner chain on each recording electrode in the case of FIG. 3a, and FIG. 4a is a bottom view showing the toner particle pulling range in the conventional device. FIG. 4b is a bottom view showing the state of the toner chain on each recording electrode in the case of FIG. 4a, and FIG. a bottom view showing a state in which the retraction ranges of the are spaced apart from each other;
FIG. 5b is a sectional view showing the state of the toner chain on each recording electrode in the case of FIG. 5a, FIG. FIG. b is a sectional view showing the main parts of the embodiment. 1... Sleeve, 2... Magnetic roll, 3... Hopper, 6... Toner, 10... Power supply, 11...
Back electrode, D ₀ , D _o+1 ... dummy electrode, E ₁ ~ _{E o} ...
...Recording electrode, S ₁ -S _o ...Switching means.

Claims (1)

[Claims] 1. A plurality of aligned recording electrodes made of ferromagnetic material, a back electrode facing these recording electrodes,
a magnet facing the back electrode via the recording electrode; means for supplying a recording medium between the recording electrode and the back electrode; and applying a voltage between the recording electrode and the back electrode. In the recording apparatus, the recording device comprises: a means for supplying powdered toner containing a ferromagnetic component and having conductivity around the recording electrode; A recording device characterized in that a dummy electrode made of a ferromagnetic material is provided. 2. The recording device according to claim 1, wherein the dummy electrode is grounded.