JPH0679860B2 - Ion flow control recording head - Google Patents

Description

The present invention relates to an ion flow control recording head that controls an ion flow to form an electrostatic latent image.

"Prior Art" A conventionally known recording head for controlling ion flow (Japanese Patent Laid-Open No. 59-
The principle of JP 190854) will be described with reference to FIG.

This ion flow control recording head is composed of a discharge wire 10, a shield 11 surrounding the discharge wire 10, and a substrate 16 mounted in front of a slit 12 provided in the shield and having an electrode array 15 mounted thereon.

The shield 11 has slits 12 and 13 which are parallel to the longitudinal direction on the lower surface and the upper surface of the drawing. It is made of a conductor such as stainless steel.

A substrate 16 is fixed to the lower surface of the shield 11 via an insulating plate 14.

On the upper surface of the substrate 16, an electrode array 15 composed of a large number of electrodes arranged in parallel at a predetermined pitch is formed.

FIG. 4 is a sectional view taken along the line II-II of the head shown in FIG.

Here, a discharge power source 17 having a predetermined voltage is connected to the discharge wire 10, and the shield 11 is grounded.

Further, the electrode array 15 includes a control circuit 18 for controlling the ion flow.
Are connected.

On the other hand, air is sent into the slit 13 in the direction of arrow 21 from a compressor or the like (not shown), and a certain amount of air flows out of the slit 12 as indicated by arrow 22.

A recording medium 23 made of an insulator is arranged in front of the arrow 22. A counter electrode 24 is arranged on the back surface of the recording medium 23 and is connected to a negative power source 25.

Here, when a predetermined voltage is applied to the discharge wire 10 from the power supply 17, positive ions 26 are generated and flow toward the shield 11. On the other hand, since the air flow is generated in the directions of the arrows 21 and 22, a part of the positive ions 26 tries to flow between the electrode array 15 and the shield 11 toward the recording medium 23.

At this time, if the potential of the electrode array 15 is selectively switched,
The ion flow does not flow out from the electrode portion having the high potential, and the ion flow flows toward the recording medium 23 only from the electrode portion having the low potential.

As a result, ions are selectively supplied to the recording medium 23.

The recording medium 23 is sub-scanned at a predetermined speed in the direction of arrow 27,
An electrostatic latent image corresponding to a predetermined image is formed on the recording medium 23.

Here, the relationship between the configuration of the electrode array and the ion flow is
This will be described with reference to FIG.

In this figure, three electrodes E1, E2, E3 are shown.
(Fig. 5a). If all electrodes are at low potential,
As described above, the ion flow of positive ions flows out in the direction of arrow 22 in FIG.

In this case, a certain fluctuation occurs in the ion flow along the longitudinal direction of the head corresponding to the arrangement pitch of the electrodes E1 to E3 (FIG. 5b).

Here, if only the electrode E2 becomes high potential, this electrode E2
The flow of ions through the part of is blocked, and a dip in the flow of ions occurs there (Fig. 5c).

Here, if only this electrode E2 is continuously kept at a high potential for a certain period of time, an electrostatic latent image corresponding to a straight line with this width is formed on the recording medium. This straight line will be called a 1-bit line in the present invention.

As shown in FIG. 5c, the minimum value of this 1-bit line dip is
Although the level is such that the ion current does not flow, if the slope of the falling portion 5 is not sufficiently large, so-called crosstalk will occur.

Therefore, for example, as shown in FIG. 6, it is conceivable to improve the inclination of the falling portion by using a comb-shaped electrode having slits 6 at the tips of the electrodes E1 to E3.

In this case, the fluctuation pitch of the flow rate of the ion flow in the normal state becomes smaller (b in the same figure).

Then, when the electrode E2 has a high potential, the effect of causing the falling 5'with a large inclination is obtained.

[Problems to be Solved by the Invention] However, regarding the comb-teeth-shaped electrode shown in FIG. 6, considering the productivity and the like, the arrangement density of the electrode tip portions divided by the slits 6 is 1 mm. There is a limit of about 24 wires. Therefore, the arrangement density of the electrodes themselves is limited to 8 per millimeter, which is not suitable for forming a high-density and high-quality electrostatic latent image.

On the other hand, there is also an ion flow control method in which the ion flow is always interrupted by an electrode and a control voltage is applied to a specific electrode to selectively take out the ion flow.

FIG. 7 shows the relationship between the electrode and the ion flow when the method is used.

When all the electrodes E1, E2, E3 are in the state of extracting the ion flow, as shown in FIG. 7b, the ion flow fluctuates at the same pitch as the arrangement pitch of the electrodes.
Here, when the ion flow is controlled so as to be taken out only from a specific electrode, for example, E2, the ion flow is distributed in a distribution 7 as shown in FIG. leak.

In this case, the peak value is lower than the ideal distribution 8 that should originally flow out, and the flow rate of the entire ion flow is small.

As a result, there is a problem that the 1-bit line becomes thin or broken after development. Of course, the example shown in FIG. 5 has the same drawbacks.

The present invention has been made by paying attention to the above points. The density of electrodes can be increased, crosstalk between electrodes can be reduced, and reproducibility of one bit line can be improved. It is an object of the present invention to provide an ion flow control recording head.

"Means for Solving Problems" In the present invention, an ion flow flowing out from a slit is controlled by using an electrode array in which a large number of electrodes are arranged in a line, and an electrostatic latent image is formed by ions on a recording medium. In the ion flow control recording head, the electrode array is configured by alternately arranging the main electrode and the guard electrode at regular intervals, and when the main electrode is switched to a potential for extracting the ion flow, it is arranged on both sides of the electrode. Adjacent guard electrodes are switched to almost the same potential as this, and other guard electrodes are provided with a control circuit that supplies a control voltage so as to maintain a potential at which the ion current before extraction is switched to a potential at which the ion current is not extracted. It is characterized by that.

That is, in the present invention, the electrode array is configured by alternately arranging the main electrode and the guard electrode at regular intervals, and when the potential of the main electrode is switched, the guard electrode adjacent to it is almost the same. The control circuit is controlled so as to switch to the same potential so that the same potential as the main electrode appears over the width of the main electrode. Since the crosstalk is sufficiently improved by the guard electrode portion adjacent to the portion where the potential of the main electrode is switched in this way, a sufficient amount of ion flow can be secured. Moreover, since the guard electrodes other than this are held at a potential that does not take out the ion current before being switched to the potential for taking out the ion current, noise is not generated and one bit line can be reproduced clearly without interruption. You can

Moreover, in the present invention, since the electrode array has only the main electrodes and the guard electrodes, the structure is simplified and the arrangement pitch can be relatively high.

"Embodiment" FIG. 1 is an explanatory view of the relationship between the configuration of an electrode array and the ion flow rate showing an embodiment of the ion flow control recording head of the present invention.

The electrode array of this embodiment has a structure in which main electrodes E1 to E4 and guard electrodes G1 to G4 having a width of a fraction of the main electrodes are alternately arranged. Of course, this electrode array
Needless to say, a large number of such main electrodes and guard electrodes are continuously arranged in the left-right direction in the drawing.

Each of the main electrodes E1 to E4 controls recording of one bit of a pixel of the electrostatic latent image.

The guard electrodes G1 to G4 are used to adjust the electric field between the main electrodes to optimize the ion flow.

FIG. 2 shows a wiring example of a circuit for applying a signal voltage to such an electrode array.

Each of the main electrodes E1 to E4 has a buffer circuit 51 for a switch circuit 40 for turning on and off a signal voltage supplied thereto.
Connected through. The buffer circuit 51 is composed of a known TTL (transistor-transistor logic) circuit.

Further, each of the guard electrodes G1 to G4 is wired so as to receive the control voltage to the main electrodes E1 to E4 adjacent on both sides thereof via the AND gate 52.

The switch circuit 40 is provided with a number of switches 41 corresponding to the respective main electrodes E1 to E4. These switches 41 are connected so as to be turned on to the high potential side and the low potential side, respectively, according to a predetermined image signal.

A positive power source 42 is connected to the high potential side of the switch circuit 40, and the low potential side is grounded.

Further, in this ion flow control recording head, when the main electrodes E1 to E4 are set to a low potential, the ion flow flows out from the main electrodes E1 to E4 and an electrostatic latent image is formed on the recording medium.

Now, returning to FIG. 1, FIG. 1b shows the case where all the main electrodes and the guard electrodes of this electrode array are set to low potential, and the ion flow is completely discharged. In this case, it can be seen that the ion flow fluctuates along the longitudinal direction of the electrode array corresponding to the widths and the arrangement pitches of the main electrodes E1 to E4 and the guard electrodes G1 to G4, respectively.

Here, for example, if only the main electrode E2 is set to a low potential, the ion flow will flow out in the distribution as shown by the curve 31 in FIG.

This is as described in FIG. As described above, there is a problem that the 1-bit line becomes thin or broken.

On the other hand, in the present invention, when only the main electrode E has a low potential, the guard electrodes G1 and G2 on both sides of the main electrode E are controlled to have substantially the same potential. As a result, the electric field on both sides of the main electrode E2 becomes lower in potential, and as shown by the curve 32 in FIG. 1c, the slope of its rising portion is large and its peak value is also high. That is, it is possible to flow out a sufficient amount of ion flow.

As described above, in this embodiment, when one main electrode is switched to the low potential, the guard electrodes on both sides of the main electrode always have the same potential. Also, for example, two adjacent main electrodes
When E2 and E3 have a low potential, the guard electrode G2 sandwiched between the two main electrodes and the two guard electrodes G1 and G3 sandwiching these main electrodes have the same potential.

Such control is realized by the circuit shown in FIG.

The circuit of FIG. 2 shows a case where the main electrode E2 is at a low potential and the two guard electrodes G1 and G2 sandwiching the main electrode E2 are also at a low potential.

In the figure, the potential of each wiring is shown as "H" when it is high and "L" when it is low.

First, when the switch 41 connected to the main electrode E2 is turned on to the low potential side, this signal is transmitted to the main electrode E2 via the buffer 51. That is, the main electrode E2 has a low potential. At the same time, the output of the buffer 51 is input to two adjacent AND gates 52 and one of the terminals is set to a low potential. As a result, the output of each of the AND gates 52 has a low potential, and the guard electrodes G1 and G2 connected to these AND gates 52 have a low potential.

In this way, a good 1-bit line can be reproduced by the main electrode E2.

As described above, for example, when the main electrodes E2 and E3 are set to low potential, the guard electrodes G1, G2, and G3 operate to be low potential.

"Modification" The ion flow control recording head of the present invention is not limited to the above embodiments.

The same thing can be done in a system in which the potential of the main electrode is switched so as to block the flow of ions.

The potentials of the main electrode and the guard electrode do not necessarily have to be controlled to be completely equal, and may be approximately the same. Further, the circuits for controlling the potentials of these electrodes are not limited to those shown in the embodiment, and may be freely selected and changed.

[Advantages of the Invention] As described above, according to the present invention, the electrode array is configured by alternately arranging the main electrodes and the guard electrodes at regular intervals, thereby increasing the array density of the electrodes. In addition, since the structure is simple, high density recording can be performed. Further, since the guard electrode is arranged between the main electrodes, crosstalk can be effectively prevented and a high-quality electrostatic latent image can be formed. Further, in the present invention, when the potential of the main electrode can be switched, the control circuit is controlled so that the guard electrode adjacent to the main electrode can be switched to substantially the same potential as that of the main electrode so that the width is substantially the same as the width of the main electrode. In addition to allowing the potential to appear, the other guard electrodes were held at a potential that did not take out the ion flow before switching to the potential that takes out the ion flow, so fine lines and fine parts may be thinned more than necessary. Image information can be accurately reproduced without interruption.

[Brief description of drawings]

FIG. 1 is an explanatory view of the relationship between the configuration of an electrode array and the ion flow rate showing an embodiment of an ion flow control recording head of the present invention, FIG. 2 is a connection diagram of its control circuit, and FIG. 3 is a conventional ion flow. FIG. 4 is a perspective view of the control recording head, FIG. 4 is a cross-sectional view taken along the line II-II, FIG. 5 is an explanatory view of the relationship between the configuration of a conventional electrode array and the ion flow rate, and FIGS. 6 and 7 are conventional. FIG. 7 is an explanatory diagram of a relationship between the configuration of another electrode array and the ion flow rate. E1 to E4 …… Main electrodes, G1 to G4 …… Guard electrodes.

Claims (1)

[Claims] 1. A method for controlling an ion flow flowing out from a slit by using an electrode array having a large number of electrodes arranged in a line to form an electrostatic latent image by the ions on a recording medium, wherein the electrode array comprises: The main electrode and the guard electrode are alternately arranged at a constant interval, and when the main electrode is switched to a potential for extracting the ion current, the guard electrodes adjacent to both sides of the main electrode and the guard electrode are An ion is characterized in that a control circuit is provided for switching to substantially the same potential, and for the other guard electrodes, a control voltage is provided so as to maintain a potential at which the ion current before being switched to the potential at which the ion current is taken out is not taken out. Flow control recording head.