JPH0636927Y2 - Ion flow control recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to an ion flow control recording head used in a recording device that performs electrostatic recording using an ion flow, and particularly stabilizes the control voltage of its drive unit. Ionized flow control recording head.

"Prior Art" An ion flow control recording head is used to form an electrostatic latent image on a recording medium by controlling the flow of ions.

6 and 7 are for explaining the operating principle of this ion flow control recording head. (JP-A-60-89373
(See the official gazette). In the apparatus shown in FIG. 6, an ion generator 11 having a U-shaped cross section has a corona wire 12 stretched in its internal space. When a high voltage of several kilovolts is generated between the ion generator 11 and the corona wire 12 by the power supply 13, corona discharge occurs and ions are generated from the corona wire 12. A counter electrode 14 is arranged so as to face the ion generator 11 and is grounded. Then, the generated ions pass through the ion flow control hole 15 disposed between the ion generator 11 and the counter electrode 14 and proceed toward the counter electrode 14 due to the electric field formed by the both. Here, the ion flow control hole 15 has, for example, a diameter.
It is a hole of about 100 to 500 μm.

The amount of ions passing through the ion flow control hole 15 is controlled by the electric field formed by the upper control electrode 16 and the lower control electrode 17. The power supply 18 is provided for this control. That is, when the power source 18 is connected as shown in FIG. 6, the electric field formed by the ion generator 11 and the corona wire 12, the upper control electrode 16 and the lower control electrode
The electric fields formed by 17 are set in the same direction.
In this case, the ions pass through the ion flow control hole 15 like the ion flow 19 shown in the figure, and charges are accumulated on the recording medium 21 provided in front of the counter electrode 14.

On the other hand, as shown in FIG. 7, when the power source 18 is reversely connected to the upper control electrode 16 and the lower control electrode 17, the electric field is reversed and the ions take the form of the ion flow 22. Therefore, at this time, the ions do not pass through the ion flow control hole 15, and no charge is accumulated on the recording medium 21.

According to the principle shown in FIGS. 6 and 7, an electrostatic latent image is formed on the recording medium 21 in a desired pattern.

FIG. 8 shows a main part of a recording apparatus using the ion flow control recording head having the above principle. (See JP-A-59-190854). In the proposed device, a discharge wire (corona wire) 26 is provided in the internal space of a shield 25 having slits 23, 24 at the upper and lower portions. The shield 25 is made of a conductor such as stainless steel, and the lower end portion of the shield 25 is covered with an insulating plate 27.
28 are arranged. An electrode array 29 in which a large number of electrodes are arranged in parallel at a predetermined interval on the surface of the substrate 28 facing the shield 25.
Are formed. Each electrode forming the electrode array 29 is connected to the output side of a control circuit 31 for ion control.

FIG. 9 is a sectional view taken along line II-II of the apparatus shown in FIG. As shown in this figure, the shield 25 is grounded, and a positive voltage is applied to the discharge wire 26 from a power source 33. Further, a predetermined pulse voltage is selectively applied to the electrode array 29 formed on the substrate 28 by the control circuit 31 described above.

When the air is sent from the slit 23 of the shield 25 as shown by the arrow 34 in such an apparatus, the air is discharged through the slit 24 in the direction of the arrow 35 by a predetermined amount. Since a positive voltage is applied to the discharge wire 26, positive ions 36 are generated from this and flow toward the shield 25. Some of them pass through the slit 24 along with the flow of air and try to flow out in the direction of arrow 35.

By the way, a recording medium 37 made of an insulating material is arranged in the air outflow direction. On the back surface of the recording medium 37, a counter electrode 39 connected to a negative power source 38 is arranged. Therefore, in the portion of the electrode array 29 to which the positive high voltage is applied,
The ions 36 do not pass through the slit 24, and no ions are supplied to the corresponding portion of the recording medium 37. On the other hand, in such a portion of the electrode array 29 to which such a high voltage is not applied, the ions 36 pass through the slit 24 and are supplied to the corresponding portion of the recording medium 37. If the recording medium 37 is sub-scanned in the direction of arrow 41 at a predetermined speed, a predetermined electrostatic latent image is formed on the recording medium 37.

8 and 9, the ion supply in the main scanning direction is controlled by the electrode array 29 in which a large number of electrodes are arranged in parallel. On the other hand, FIG. 10 is a cross-sectional view of an ion flow control recording head having a structure slightly closer to that of FIGS. 6 and 7 as viewed from the side. Pinholes 44 are formed on the substrate 43 at predetermined intervals. An ion flow 45 flows from the upper part to the lower part of the pinhole 44. An electrode array 46 is arranged on the upper surface of the substrate 43, and an electrode 47 for adjusting the flow of the ion current is arranged on the lower surface. The control circuit 31 is mounted on the electrode array 46 on the side where the pinhole 44 is not formed. This control circuit
An integrated circuit 51 is attached to the electrode array 46 via an insulating layer 49, and a mold layer 53 for protecting the whole.

In the two types of ion flow control recording heads shown in FIGS. 8 to 10, the electrodes provided corresponding to the respective pixels are selectively driven by the control circuit 31 to control the ion flow. It will be.

[Problems to be Solved by the Invention] In the conventional ion flow control recording head thus proposed, the control voltage is held by the electrostatic capacity of the electrode itself or the wiring. That is, in such a conventional control circuit, one thin film transistor is arranged corresponding to each electrode, and when each thin film transistor is selected by a select signal which will be described in detail later, a current flowing through these thin film transistors according to an image signal. Was in control. Electric charges are accumulated in the electrostatic capacitance by this current, and the voltage applied to each electrode is controlled depending on the presence or absence of the electric charges or the amount of accumulated charges.

Therefore, in such a control circuit, there is a problem that the control voltage of each electrode cannot be maintained at a predetermined value when the charge held in the electrostatic capacity is lost due to the current leakage of the thin film transistor. As described above, in the conventional ion flow control recording head, the ion flow is not always ideally controlled, and it is difficult to realize high-quality image quality.

Therefore, an object of the present invention is to provide an ion flow control recording head capable of keeping the control voltage output from the control circuit constant.

[Means for Solving the Problem] In the present invention, the electrode array and the control circuit are formed on the same substrate, and each has the following configuration.

The electrode array has a large number of electrodes arranged with a non-electrode portion sandwiched therebetween, and the voltage applied to these electrodes is controlled on a pixel-by-pixel basis to control passage of an ion current.

The control circuit includes (i) capacitors provided corresponding to the respective electrodes, (ii) charging voltage control transistors provided corresponding to the capacitors and supplying charges corresponding to the image signals to the capacitors, (iii) ) Pull-up resistors provided respectively corresponding to the charging voltage control transistors, and (iv) receiving a current flowing between the source and drain from these pull-up resistors and controlling the gate voltage by the above-mentioned capacitor. , Arranged in a matrix for supplying a drive signal to the control voltage applying transistor for applying the voltage at the connection point with the pull-up resistor that changes thereby to the corresponding electrode, and (v) each charging voltage controlling transistor. It is composed of a wiring pattern.

Thus, according to the present invention, two electrodes are provided for each electrode.
Different types of transistors are prepared, and the charging voltage controlling transistor controls the charging voltage of the capacitor, and the charging voltage controls the control voltage applying transistor to control the applied voltage to the corresponding electrode. In the control circuit of the present invention, the gate of the control voltage applying transistor consumes almost no current. Therefore, the charging voltage of the capacitor does not change with time, and the voltage applied to each electrode can be stabilized.

[Examples] The present invention will be described in detail below with reference to examples.

FIG. 1 is a sectional view showing a main part of an ion flow control recording head according to an embodiment of the present invention. The same parts as those in FIG. 9 are designated by the same reference numerals, and the description thereof will be appropriately omitted.

Now, also in the ion flow control recording head of this embodiment, the substrate 28 is attached to the shield 25 via the insulating plate 27. A control circuit 74 including a drive unit 72 and a wiring pattern 73 is formed on the substrate 28 via an insulating layer 71 on the side opposite to the side from which the ion flow flows. The drive section 72 is formed of a thin film transistor and a capacitor as described later, and is formed to have a thickness of several μm by a known method like the wiring pattern 73. The control circuit 74 is connected to the electrode array 29 by a wiring pattern 73, and applies a control voltage to each of a large number of electrodes forming the array.

FIG. 2 shows a part of a circuit configuration diagram of the control circuit of the ion flow control recording head.

The electrodes 76 as a constituent unit of the electrode array 29 are arranged corresponding to the pixels for one scanning line, and usually 2000 to 3000 are arranged according to the recording density. In the ion flow control head of this embodiment, the electrode is used because of the relationship between the recording density and the recording width.
2880 pieces of 76 were prepared on the substrate 28. A drive unit 72 is prepared for each of the electrodes 76 one by one. Here, the drive unit 72 is a circuit portion that outputs a control voltage according to the image signal.

Now, each of the electrodes 76 and the driving section 72 is divided into N groups of M pieces. The select lines S1 to SN are connected to the driving unit 72 one by one for each group. Each group has M drive units, one for each M
The data lines D1 to DM of the book are connected. In Figure 2,
The first group is represented by a code and the second group is represented by a code. Illustrations of the third to Nth groups are omitted. In this way, each drive unit 72 includes the select lines S1 to SN and the data lines D1 to DM arranged in a matrix.
Are selected according to the combination of the signal outputs of the above, and the control voltage is output to the electrode 76 at that time. In this embodiment, N is set to 60, and M is set to 48 in consideration of the total number of the electrodes 76, 2880.

FIG. 6 shows a concrete structure of the drive unit.
The drive unit 72 includes first and second transistors 81 and 82 as thin film transistors. First transistor
The gate of 81 is connected to the select line S shown in FIG. 2, and the select signal 83 is supplied.
When the first transistor 81 is turned on by the select signal 83, that is, the M electrodes 76 of the corresponding group.
Is designated, the charging of the capacitor 85 is controlled according to each state of the data signal 84 supplied to the data lines D1 to DM (FIG. 2). The charging voltage of the capacitor 85 is supplied to the gate of the second transistor 82.
The pull-up resistor 86 and the second transistor 82 are controlled by the on / off control of the second transistor 82.
The potential at the connection point of 82 fluctuates, and this is applied to the corresponding electrode 76 as the control voltage 87.

For example, in this embodiment, the data signal is changed according to the state of the image signal.
84 is set to one of the predetermined voltages of 0 and 5 to 30 volts. If the data signal 84 is 0 volts,
The capacitor 85 is not charged and no potential difference is generated across the capacitor 85. Therefore, the second transistor 82 is also kept off, and the voltage applied to the pull-up resistor 86 (30 volts in this case) is applied to the corresponding electrode 76.

On the other hand, if the data signal 84 is, for example, 5 volts, this causes the capacitor 85 to be charged. This charging voltage turns on the second transistor 82. Therefore, the pull-up resistor 86 causes a potential drop and the voltage applied to the electrode 76 becomes 0 volt.

Now, when the select signal 83 is turned off, the capacitor 85 can well hold the charging voltage until it is turned on next time. This is because the second transistor 82 is formed as a field effect transistor in the manufacturing method of the thin film transistor, so that the electric power discharged from the capacitor 85 via the gate is negligibly small. Therefore, the potential of the electrode 76 hardly decreases with time, and it is possible to prevent the ion flow of the ion flow control recording head from changing with time.

In the ion flow control recording head of the embodiment described above, the control circuits are arranged in the select lines S arranged in a matrix.
And driven by the group using the data line D.
Therefore, first, the image data is supplied to the first select lines D1 to DM. Then, the operation of forming the electrostatic latent image is started for the first group indicated by the symbol in FIG. After that, the designation of the first select line S1 is canceled at the next timing, and the designation of the second select line S2 is performed instead. Then, the image data for the second group is supplied to the first to Mth data lines D1 to DM. At this time, the first
With respect to the group (2), the electrostatic latent image forming operation is continuously performed depending on the charged state of each capacitor 85.

In the same manner, the work for forming the electrostatic latent images is performed on the third to Nth groups. In this way, an electrostatic latent image is formed on one main scanning line, and the latent image is formed by repeating this line by line. At this time, the main scanning speed is, of course, sufficiently higher than the sub-scanning speed.

"Modification" FIG. 4 is for explaining a modification of the ion flow control recording head of the present invention. The ion flow control recording head of this modification has the same circuit configuration as that of the previous embodiment, but the substrate configuration is devised.

That is, as shown in FIG. 4, in this ion flow control recording head, a conductor 92 is formed with a thickness of several μm on a substrate 91 such as glass. The formation of such a conductor 92 can be realized by firing or vapor deposition of a metal paste. On the conductor 92, a resistance layer 93 having a thickness of several μm is also used.
Is formed. The resistance layer 93 has a resistance value adjusted by dispersing a conductor powder made of metal, carbon or the like in an organic medium, and a surface resistance per unit square of 10 ³ Ω / □ to 10 ³ Ω / □ is suitable. If the resistance value is lower than this range, the insulation formation as the non-electrode portion of the electrode array cannot be maintained. Also, if the height is higher than this range, the gap between the electrodes is likely to be charged with ions, and the flow of the ion current is disturbed.

In this modification, glass is used as the substrate 91 and the conductor 92
Aluminum was used as. Further, as the resistance layer 93, one in which carbon is dispersed in urethane is used,
This was grounded. A pattern of electrodes 94 was formed on the resistance layer 93.

As shown in FIG. 4, the resistance layer 93 is arranged on a part of the substrate 91 in this modification, but it may be arranged on the entire surface of the substrate 91. FIG. 5 shows a circuit configuration in this case. Thus, in this case, the electrode 76 is grounded via the resistor 95. Here, the resistance 95 is the resistance of the resistance layer 93 plus the resistance of the adjacent electrodes. Even in this case, if the resistance value of the pull-up resistor 86 and the voltage of the power supply connected to the pull-up resistor 86 are appropriately selected, it is easy to apply a voltage of about 30 V to the electrode 76. Further, in this modification, the resistance layer and the conductor layer are attached only to the non-electrode portion, but this is not particularly difficult in the current fine processing technology.

In the modified example described above, the surface of the non-electrode part made of glass or the like can be effectively prevented from being charged by the effect of passing ions, and the passage of the ion flow is not hindered. Therefore, also in this sense, it becomes possible to prevent the image quality from being defective and form a high-quality image.

[Advantage of Invention] As described above, according to the present invention, since the thin film transistors are configured in two stages and the capacitors are arranged for voltage control, the control voltage can be sufficiently stabilized even if the capacitors have a relatively small capacity. The responsiveness of the driving portion can be improved by this amount. In addition, since the electrodes are grouped in a matrix in the present invention, the total amount of wiring can be reduced.

[Brief description of drawings]

1 to 3 are for explaining an example of the present invention, in which FIG. 1 is a sectional view showing a side surface of an ion flow control recording head, and FIG. 2 is a part of a circuit configuration of a control circuit. FIG. 3 is a block diagram showing the structure, FIG. 3 is a circuit diagram showing a concrete structure of the driving unit, FIG. 4 is a cross-sectional view showing the structure of the substrate in a modified example, and FIG. FIG. 6 and FIG. 7 are principle diagrams showing the operating principle of the ion flow control recording head, and FIG. 8 is a diagram of a conventionally proposed ion flow control recording head. FIG. 9 is a perspective view showing a main part, FIG. 9 is a partial sectional view of a recording apparatus using an ion flow control recording head, and FIG. 10 is a principle view showing another principle of ion flow control. 76 ... Electrode, 83 ... Wiring pattern, 81 ... First transistor (for charging voltage control), 82 ... Second transistor (for control voltage application), 86 ... Pull-up resistor, 93 ... Resistor layer.

Claims (1)

[Scope of utility model registration request] 1. An electrode array for controlling the passage of an ion current by arranging a large number of electrodes with a non-electrode portion interposed therebetween and controlling a voltage applied to these electrodes on a pixel-by-pixel basis. Capacitors provided, charging voltage control transistors that are provided corresponding to these capacitors and that supply charges according to image signals to these capacitors, and pull-up resistors that are provided corresponding to these charging voltage control transistors, respectively. And, the gate voltage is controlled by the capacitor while the current flowing between the source and the drain is supplied from these pull-up resistors, and the voltage at the connection point with the pull-up resistor that changes by this is applied to the corresponding electrode. A matrix-like transistor that supplies control signals and the drive signals to each charge voltage control transistor. And a placed wiring pattern, ion flow control recording head characterized by comprising a control circuit disposed on the electrode array on the same substrate.