JPH04211971A - Electrostatic recorder - 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]

0001

[Purpose of the invention]

0002

[Industrial Application Field] This invention relates to an electrostatic recording device.
In particular, the present invention relates to an electrostatic recording device that uses ions to form an electrostatic latent image on a recording medium.

0003

[Prior Art] In ion deposition recording, ions (corona ions) generated by corona discharge in the air are directly controlled according to image signals to form an electrostatic latent image, which is then developed to form a hard disk. It is a type of electrostatic recording method for non-impact recording to obtain copies. In this type of electrostatic recording device,
Ion current recording heads and dielectric recording media are used in place of photosensitive recording media that utilize laser optics and photoconductive layers in laser printers that use light beams to form electrostatic latent images.

The concept of generating ions in the air for electrostatic recording is older than laser printers, and involves heating a metal electrode to a high temperature in the air and simultaneously applying a high voltage to generate ions to perform electrostatic recording. As a method, in 1938 Seleny
i, but it has not been put into practical use.

[0005] In addition, Delfax Corporation of the United States noticed that high-density ions are generated when high-frequency, high-voltage is applied to two electrodes with an insulating layer sandwiched between them, and in 1982 they successfully commercialized this product as a label printer. ing. This method uses a 1 MHz, 2.8 kVP-
The high-frequency high voltage of P and the 600V voltage for transporting ions to the recording medium are switched for each pixel-corresponding electrode according to the image signal, and high-speed binary recording (500 sheets/min, A4 equivalent) is performed. It is said that high-volume printing can be performed using a high-hardness alumina recording medium with maintenance required only once every 100,000 sheets. This method is described in US Pat. No. 4,155,093, for example.
It is disclosed in Japanese Patent Application Laid-Open No. 54-53537. This is a recording method in which an ion stream is irradiated onto a dielectric recording medium to form an electrostatic latent image, which is then developed to form an image.

[0006] The electrostatic recording method using this ion flow is superior to electrophotographic recording using optical input such as a laser printer in terms of high speed and ease of maintenance. In terms of speed, the method using ion flow has a speed of 330
Announcement of sheets per minute (A4) (SPSE, The 4th
international congress
advancements in non-impact
printing technologies:
March 20-25, 1988, p394-39
7), which is several tens of times faster than the recording speed of 6 to 8 sheets per minute (A4), which is the recording speed of ordinary commercially available laser printers. In addition, recording methods using ion currents have a high volume resistivity (1014
-1016 Ω·cm) can be used, and the material selection range is wider than that of photosensitive recording media used in electrophotographic recording. For example, as a dielectric recording medium, an inorganic insulator such as Al2O3 with high hardness can be used, and an organic insulator can be made of a material that is resistant to ozone generated when ions are generated. There is little surface deterioration due to ozone or material deterioration due to toner surface adhesion, allowing stable recording for a long time. In addition, since recording is performed by controlling ions for each pixel and applying a charge directly to the dielectric recording medium, the recording speed is determined by the performance of the ion flow recording head, and is not affected by the characteristics of the recording medium like a laser printer. It is now possible to record without

As described above, the ion deposition recording method is (1) fast, does not require a laser optical system (light source/rotating mirror scanning system) and a photosensitive recording medium, and the device is small and stable; (2) Pulse width modulation of recording pixels is possible;
The same image quality can be obtained at a fraction of the resolution of a laser printer, and (3) since the recording medium does not use a photoreceptor with dark decay (surface potential), the charge retention time is long and intermittent recording is possible. Furthermore, (4) images can be sequentially formed on a recording medium, and high-speed one-pass color recording is expected.

A conventional recording device using a solid ion flow recording head for controlling an ion flow to obtain an electrostatic latent image has an accelerating electrode having an ion flow discharge hole corresponding to a recording image point in front of a solid ion generator. A bias voltage as high as the electrostatic latent image contrast is applied to the ion generator according to the recording signal, and the ion flow is controlled on and off to form an electrostatic latent image on the dielectric recording medium. . Solid-state ion generators are constructed by arranging an ion generation electrode and an induction electrode close to each other on a dielectric substrate, so they can generate high-density ions and can record at higher speeds than laser printers. It is possible.

FIG. 65 is a schematic cross-sectional view showing the recording operation of the solid ion flow recording head disclosed in Japanese Patent Laid-Open No. 16-184562. A dielectric electrode 902 is provided on one surface of a dielectric substrate 901, and an ion generation electrode 903 for ion generation is provided on the other surface. The ion generating electrode 903 is provided with a slit (or hole) 904 for concentrating an electric field to easily generate ions. An AC voltage 90 is applied between the induction electrode 902 and the ion generation electrode 903.
When 5 is applied, a high alternating electric field is generated in the slit 904, and high density positive and negative ions are generated. Among the positive and negative ions generated in this way, only negative polarity ions are selected by a high bias voltage 906 of 400 to 500 V, which is about the same as the electrostatic latent image potential applied to the ion generation electrode 903, and the dielectric recording medium 907 move in the direction. Ions moving in the direction of the recording medium 907 are transferred to an accelerating electrode 90 provided between the recording medium 907 and the ion generating electrode 903.
A high accelerating voltage of about 400 to 500 V applied to 8
09 and reaches the recording medium 907, forming an electrostatic latent image according to the image signal. In this way, the ion flow is controlled by turning on and off the bias voltage 906. The solid ion flow recording head is constructed by arranging a large number of head elements as shown in FIG. 65 in one dimension according to the number of pixels. Also,
A conventional xerographic corona charger may be used in place of the solid state ion generator.

However, such conventional solid-state ion flow recording heads have the following drawbacks. In a solid state ion flow recording head, a recording medium 90 is used to control the ion flow.
A bias voltage as high as the electrostatic latent image potential on 7 (40
0 to 500 V or more) as a signal voltage to the ion generating electrode 9.
It is necessary to add it to 03. This is specifically switch 9
This is achieved by switching 10 according to the image signal and applying a bias voltage 906. Therefore, an electrostatic recording device using such a solid-state ion head generally requires a driver IC with high breakdown voltage. A high-voltage driver IC requires a large mounting area and is not suitable for high-definition heads that require high-density mounting. If all dots are divided into many parts and driven in a matrix without using an IC for the drive circuit, it will be difficult to perform gradation recording (multi-value recording) by pulse width control etc. when performing high-speed recording, and it will be difficult to control on/off. Only binary recording is possible.

Furthermore, in an electrostatic recording device using a conventional ion flow recording head, all the generated ions are used when moving the ions in the direction of the recording medium 907, but in this recording method, the ions are The amount of ions generated changes due to a change in the critical voltage for ion generation depending on the surface condition of the generation electrode 903, and it is difficult to form a uniform electrostatic latent image even in the case of binary recording.

On the other hand, as a method for lowering the driving voltage of the ion flow head, a method is proposed in which ions are transported by an air flow and a control electric field is applied in a direction perpendicular to the ion flow (Japanese Patent Laid-Open No. 61-2558).
No. 70) is known. According to this method, 30
Although it becomes possible to drive at a voltage as low as V and perform multi-value recording, the electrode structure becomes complicated to form the above-mentioned control electric field, and high-density packaging is still difficult.

[0013]

[Problems to be Solved by the Invention] As mentioned above, in an electrostatic recording device using a conventional ion flow recording head, it is necessary to apply a high voltage comparable to the surface potential of the electrostatic latent image to the ion generating electrode. Because of this, the driver I that constitutes the drive circuit
A high-voltage IC with a large mounting area is required for C, making it unsuitable for manufacturing a high-definition head that requires high-density mounting, and making multi-level recording difficult. In addition, in the solid-state ion generator used in conventional ion flow recording heads, the critical voltage of ions fluctuates due to the surface condition of the ion generation electrode, so even in binary recording, it is not uniform and stable for each pixel. It was difficult to form an electrostatic latent image.

[0014] On the other hand, ion generators that can be driven at a low voltage and capable of multilevel recording have a complicated electrode structure, so they are not suitable for high-definition heads.

The present invention was made in view of the above-mentioned problems, and by realizing low voltage drive and adopting a simple electrode structure, high definition is possible, multivalue recording is easy, and uniform recording is possible. An object of the present invention is to provide an electrostatic recording device using a solid-state ion flow recording head that can form a stable electrostatic latent image.

[0016]

[Means for Solving the Problems] In order to achieve the above object, the present invention forms an electrostatic latent image by irradiating ions onto a recording medium formed by forming a dielectric layer on a conductive substrate. However, an electrostatic recording device that records an image by developing this electrostatic latent image includes at least two electrodes arranged in close proximity, and a voltage is applied between these electrodes to cause corona discharge. an ion generator that generates ions, and first and second ion generators that are arranged at a predetermined interval between the ion generator and the recording medium and each have an ion passage hole through which the ions generated from the ion generator pass. The basic feature is that the device includes a control electrode and a drive circuit that applies a predetermined potential difference to the first and second control electrodes in order to control the amount of ions passing through the ion passage hole in accordance with an image signal. shall be. The first and second control electrodes are respectively formed on both sides of a control substrate made of, for example, a dielectric substrate.

In addition, in an electrostatic recording apparatus that performs an operation of irradiating ions onto a recording medium in the main scanning direction and in the sub-scanning direction perpendicular to this to form an electrostatic latent image and develop it to record an image, An ion generator and a plurality of first and second control electrodes are arranged along the main scanning direction.

Preferred embodiments of this invention are listed below.

(1) When integrating the ion generator and the control board on which the first and second control electrodes are formed, it is desirable to bring them as close as possible in order to extract ions efficiently. The magnitude of the leakage electric field due to the applied AC or DC voltage is the ionization electric field of air (approximately 30 kV).
/cm), spark discharge occurs between the ion generator and the first control electrode. Therefore, the ion generator and the first
The distance between the control electrode and the ion generating means is desirably greater than the distance at which the strength of the leakage electric field from the ion generating means is equal to or higher than the discharge starting electric field of air.

(2) The amount of ions passing through the first and second control electrodes and reaching the recording medium is regulated to 1/2 or less of the amount of ions generated by the ion generator. is desirable.

(3) The drive circuit applies a fixed potential equal to the potential of the conductive substrate of the recording medium to one of the first and second control electrodes, and applies ions to the other electrode with respect to the one electrode. A potential higher or lower than the potential of one electrode is applied depending on the polarity of the ion, or a fixed potential higher than the potential of the conductive substrate is constantly applied to one electrode and the other electrode is applied with a potential higher or lower than the potential of the conductive substrate. Apply a potential higher or lower than the potential of one electrode. In this case, one of the first and second control electrodes is used as a common electrode, and the other electrode is individually wired so that the amount of ions passing through each ion passage hole can be independently and simultaneously controlled. be done.

[0022] With the recording medium negatively (or positively) charged in advance, a DC bias is applied to the ion generator with respect to the first control electrode, and then the first control electrode and the second control electrode are When a potential difference is applied between the ion generator and the first control electrode, an electric field E1 between the ion generator and the first control electrode, an electric field E2 between the first control electrode and the second control electrode, and an electric field E2 between the second control electrode and the recording medium. When the electric fields E3 are all in the same direction, positive (or negative) ions pass through the ion passage hole and reach the recording medium, forming an electrostatic latent image on the recording medium. Further, by setting the electric field E2 to 0 or in the opposite direction, the passage of ions is blocked.

(4) The width of the ion passage hole in the main scanning direction is preferably larger than the width in the sub-scanning direction. When viewed from the sub-scanning direction, the ion through holes may overlap or be in contact with each other.

(5) The ion passage hole has θ=tan in the main scanning direction.
-1N (N is the ratio of the pitch in the sub-scanning direction to the pitch in the sub-scanning direction) It is desirable that a predetermined number M of them are arranged in the direction of an angle θ.

(6) The lead wiring connected to the other of the first and second control electrodes (the electrode to which a potential is individually applied) may be drawn out to both sides in the sub-scanning direction. desirable. In a configuration in which a predetermined number M of ion passing holes are arranged in the direction of the angle θ with respect to the main scanning direction, when the arrangement M is an odd number, (M+1)/2 and (M-1)/
Two lines at a time, or if M is an even number, two lines at a time, or M/2 lines at a time, may be distributed and drawn out on both sides in the sub-scanning direction.

(7) When the ion generator, the first and second control electrodes, and the drive circuit are integrated as a recording head on the head support, the ion passage holes are located on the end surface of the head support. It is desirable to be present.

(8) When the ion generator, the first and second control electrodes, and the drive circuit are integrated as a recording head, the ion generator may be configured to be detachable from the recording head. desirable.

(9) When producing an ion flow recording head by bonding together a substrate on which an ion generator and a drive circuit are mounted, it is preferable to provide a pattern on the substrate for alignment during bonding. This alignment pattern is formed by, for example, holes.

(10) A plurality of at least one of the ion passage holes formed in the first and second control electrodes may be formed for each pixel formed on the recording medium. desirable. In particular, it is desirable that the ion passage holes formed in the second control electrode be smaller and more numerous than the ion passage holes formed in the first control electrode. The control electrode in which a large number of ion through holes are formed is formed of a thick metal film, a thin metal film, or a metal mesh.

[0030]

[Operation] An ion generator using two closely spaced electrodes is
Electric field leakage is extremely small. Moreover, if the distance between the ion generator and the control electrode is optimized as described above, the leakage electric field from the ion generator will not affect the electric field between the first and second control electrodes. Furthermore, if the recording medium is charged in advance with ions of opposite polarity to the ions passing through the ion passage hole, the generated ions will be accelerated by the electric field formed by the ions on the recording medium.

For these reasons, it is possible to reduce the potential difference between the first control electrode and the second control electrode to several tens of volts, thereby achieving a reduction in the voltage of the drive circuit. This is about the same as the driving voltage of the thermal head conventionally used in thermal recording devices, so it is possible to use a driver IC with a small mounting area, and the recording head can be made into an IC, smaller, and higher definition. be done.

By making the width of the ion passage hole in the main scanning direction larger than the width in the sub-scanning direction, a decrease in resolution in the sub-scanning direction can be prevented.

By arranging a predetermined plurality of ion passing holes diagonally at an angle θ with respect to the main scanning direction, the pitch of the ion passing holes in the main scanning direction can be easily reduced, and the limited number of electrodes can be reduced. Higher resolution recording becomes possible with greater precision in formation.

By distributing and drawing out the lead wires from the control electrodes to both sides in the sub-scanning direction, it becomes possible to drive each control electrode simultaneously instead of the conventional matrix drive, and it is possible to drive each control electrode individually. Be able to drive. This makes it possible to control the gradation for each pixel even during high-speed recording.

[0035] When the ion passage holes are arranged on the end face of the recording head, the recording drum, which is the recording medium, only needs to be configured so that only the width of the end face of the recording head is in contact with it, so the recording drum can be made smaller, and the recording drum can be made smaller. The entire device can be made smaller.

By configuring the ion generator to be detachable from the ion flow recording head, even if the ion generator deteriorates and the amount of ions generated decreases, there is no need to replace the entire ion flow recording head. Since you only need to replace the ion generator instead of the driver I mounted on the head.
C can be used as is.

When a plurality of ion passing holes are formed in at least one of the first and second control electrodes for one image point, some of these ion passing holes may become clogged with developing toner. Even if this occurs, ions can pass through other ion passage holes that are not clogged, so pixels can be recorded. This also achieves longer life of the ion flow recording head.

[0038]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an embodiment of an electrostatic recording device using an ion flow recording head including a corona ion generator. This electrostatic recording device includes a recording drum 1 as a recording medium, a corona ion generator 2, an ion flow recording head 3 that can be driven at low voltage, and a one-component contact developer 4.
, a function-separated type soft roller transfer device 6, a heat roller 9, and a cleaning device 11 are arranged.

The recording drum 1 has a thickness of several tens of μm on an Al drum.
It is coated with a dielectric layer made of fluorine-based resin and having a thickness of about m (~20 μm). The recording drum 1 is first uniformly charged by a negative corona ion generator 2 so that its surface potential is, for example, -600V. Next, an inverted electrostatic latent image is formed on the recording drum 1 by a positive corona ion flow controlled in an analog manner for each recording dot (picture point) by the corona ion flow recording head 3 . Next, reversal development is performed at a development bias voltage of -500V using a single-component contact developer 4 having negative polarity toner.
A toner image 5 is formed on a recording drum 1. This toner image 5 is transferred onto plain paper 7 using a functionally separated soft roller transfer device 6. As the function-separated type soft roller transfer device 6, for example, the device disclosed in Japanese Patent Application No. 140423/1983, which is stable against environmental changes and provides high transfer efficiency, is used. The toner image 8 transferred onto the plain paper 7 is fixed by a heat roller 9 and fixed onto the plain paper 7. On the other hand, the residual toner 10 remaining on the recording drum 1 is wiped off by the cleaning device 11, and the cleaned recording drum 1 is used again.

According to the electrostatic recording method which uses such a corona ion flow control head 3 and introduces the one-component contact developing device 4 and the soft roller transfer device 6, it is possible to use the electrostatic recording method that is not performed in an electrostatic recording method line printer. A new concept of step feed and intermittent drive, which was not previously available, becomes possible. Using this method, signals transmitted by signal compression, such as facsimile image signals, can also be recorded in real time. The reason why step feeding is possible is that the corona ion flow recording head 3 does not use a rotating optical system like a laser printer, so it can respond to any signal, and the dielectric recording medium is similar to a photosensitive recording medium. The temporal decay of the surface potential is small; the image density developed by the one-component contact developer 4 mainly depends on the surface potential of the recording drum 1 and does not depend on the circumferential speed of the recording drum 1; and roller transfer efficiency. depends on the transfer time when the transfer voltage is applied, but this transfer time can be set arbitrarily by changing the control pulse width in a pulse manner because the transfer voltage applied to the roller is as low as 800V (6kV in conventional charger transfer). It's for a reason.

FIG. 2 shows an embodiment in which the corona ion generator 2 and the corona ion flow recording head 3 are applied to a cleanerless electrostatic recording apparatus. The recording drum 1 on which the residual toner 10 is present is charged to -600V by the corona ion generator 2 from above the residual toner 10 . Since 85% or more of the toner is transferred onto the plain paper 7 by the transfer by the function-separated soft roller 6, the amount of remaining toner is about 15%. In such a case, the charging on the recording drum 1 is not blocked by the toner and can be charged uniformly. By irradiating the recording drum 1 charged in this manner with positive corona ions from the corona ion flow recording head 3, the potential of the portion corresponding to the recording dots is erased and an electrostatic latent image is formed. , this is developed in a one-component contact developer 4. At this time, the surface potential of the recording medium on which the residual toner 10 in the non-image area exists becomes greater than the negative bias of the developing device 4, and the residual toner 10 is easily wiped off by the developing device 4.

On the other hand, the toner in the image area that has become positive in the corona ion flow recording head 3 is attracted to the developing device 4 by electrostatic force because the potential of the image area also increases toward zero potential. Wiped off. Developed toner image 5
is transferred to plain paper 7 and fixed. The recording drum 1 after the transfer is used with the residual toner 10 remaining.

Although the electrostatic recording apparatus using techniques such as a one-component developer, roller transfer, and cleanerless technology has been described above, other electrophotographic processes and toner developing materials can be used.

FIG. 4 is a sectional view showing an embodiment of a printer to which the present invention is applied. Recording paper for recording is stocked in a cassette 421, and the recording paper is fed out one by one by a paper feed roller 418 in accordance with the recording start timing. The recording paper fed out from the paper feed roller 418 is U
The conveyance direction is changed to the direction of the drum (recording medium) 1 by a turn roller 415, and the direction of the recording paper is adjusted by an aligning detector 414 and an aligning roller 413 and reaches the recording drum 1.

On the other hand, the drum 1 starts rotating at the recording start timing, and an image corresponding to the recorded image is formed on the drum 1. The recording drum 1 will be described later, but here it has a structure in which an aluminum drum is coated with an insulating dielectric layer made of fluorocarbon resin and having a thickness of about 10 to 20 μm. The recording drum 1 as described above is first uniformly charged to -600V by the precharger 401. Then, using the ion flow recording head 3 on the uniformly charged recording drum 1, an electrostatic latent image is formed by a positive ion flow controlled in an analog manner for each recording dot. This head 3 will be explained in detail later. Furthermore, air is sent to the ion flow recording head 3 via a blow tube 407 by a compressor 408 comprising a blow motor 409 . The reason why this air is necessary will be explained later.

The recording drum 1 on which the electrostatic latent image has been formed by the ion flow recording head 3 is further processed by a developing unit 40.
5, development is performed. The developing unit 405 includes a magnet roller 402, as is generally used.
It is composed of a toner sensor 403 and a shaft 404, and one-component negative polarity toner is stirred by the shaft 404. A toner sensor 403 detects the amount of toner. On the recording drum 1 side of the magnetic roller 402, reversal development is performed with a bias voltage of -500V.

The toner image formed on the recording drum 1 is
Recording paper transfer charger 419 wrapped around recording drum 1
The recording paper is peeled off from the recording drum 1 by the peeling charger 420 and conveyed toward the exit direction. After the toner transfer to the recording paper has been completed, the recording drum 1 is cleaned of residual toner in a cleaner unit 437. The cleaner unit 437 includes a cleaning blade 436 for scraping off toner, a collection blade 435 and a toner collection auger 434 for receiving the scraped toner. The cleaned recording drum 1 is then uniformly charged by the precharger 401, and the above process is repeated thereafter.

On the other hand, the recording paper onto which the toner image has been transferred is conveyed to a fixing unit 430 by a belt unit consisting of a belt 422 and a belt conveyance shaft 423. The fixing unit 430 includes a heat roller blade 429, an exit roller 428, a peeling claw unit 427, a heater lamp 426, a heat roller 425, and a thermistor 424. The toner is fixed by heat from a heater lamp 426 built into the heat roller 425. Thermal control of the heater lamp 426 is performed using the thermistor 42.
This is done by a signal from 4. After fixing, the recording paper is transferred to the upper heat roller 425 by the peeling claw unit 427.
Peels off more smoothly. The recording paper that has completed the fixing process is discharged toward the exit by two exit rollers 428. Note that the heat roller 425 is provided with a blade 429, and this blade 429 cleans unnecessary toner.

The fixed recording paper is conveyed in the exit direction,
The paper is discharged onto a tray 438 by an exit roller 433 driven by the detection of the exit switch 432, thereby completing a series of recording operations. Further, although the description is omitted, this system is also provided with a cassette detector 417 for detecting the cassette 421, a heater 416 for preventing dew condensation, and a control board 406 as in a normal printer. Further, although automatic paper feeding has been explained in the above example, manual feeding may also be used. In this case, guide 4 that receives manual paper
10, a detector 411 for detecting manual paper, and a manual paper feed roller 412 driven by the output of this detector 411.

Next, the ion flow recording head 3, which is the main part of the electrostatic recording apparatus of the present invention, will be explained using the schematic diagram of FIG. In the following explanation, a case will be considered in which the surface of the recording drum 1, which is a recording medium, is precharged with negative ions, and then an electrostatic latent image is formed by irradiating positive ions with the ion flow recording head 3.

In FIG. 3, the ion generator 20 includes an insulating substrate 21 (for example, a ceramic substrate), an induction electrode 22 formed on the substrate 21 with a thickness of several μm (2 to 3 μm), and an inductive electrode 22 with a thickness of several tens of μm (~2 μm). 20 μm) and an insulating layer 23 with a thickness of several 10 μm (~18 μm) formed on the insulator layer 23.
μm) ion generating electrode 24 and ion generating electrode 2
The shield electrode 25 is provided at the same potential as the ion generating electrode 24 with a slit 26 having a width of about 40 μm interposed therebetween.

On the other hand, the control board 30 includes an insulating board 31,
Consisting of first and second control electrodes 32, 33 formed on both sides of this substrate 31, the substrate 31 and control electrodes 32, 3
It has a large number of ion passage holes 29 that penetrate through the 3. The insulating substrate 31 is, for example, a glass polyimide sheet with a thickness of 100 μm, and copper foil with a thickness of, for example, 18 μm is pasted on both sides of the sheet as control electrodes 32 and 33, and ion passage holes 29 of about 100 μmφ are drilled at a pitch of 200 μm. It is being The control board 30 is the ion generating electrode 24
The ion generator 20 is bonded and integrated with the ion generator 20 at an appropriate distance (in the range of about 100 μm to 500 μm) via the spacer member 28 so that the center of the slit coincides with the center of the ion passage hole 29 . As a result, the corona ion flow recording head 3 is created. Further, the recording drum 1, which is a recording medium, is approximately 500 μm from the second control electrode 33.
It is located in a remote location.

The recording drum 1 is constructed by forming a dielectric layer 42 made of fluorine resin to a thickness of 10 to 50 μm on an Al drum 41 which is a conductive base. Dielectric layer 42
is precharged to a surface potential of about 600V. Here, the Al drum 41 is at a reference potential (earth potential). Further, the second control electrode 33 is at the same potential as the Al drum 41, and the first control electrode 32 is at the second control electrode when not recording.
The same potential as the control electrode 33 of the second control electrode 3 during recording.
The switching circuit 35 is controlled so that a positive control voltage Vc34 is applied to the voltage Vc34. Ion generation electrode 24
and the shield electrode 25 are the first control electrode 32 during non-recording.
A negative bias voltage Vb- 36 is applied to the first control electrode 32, and a positive bias voltage Vb+ is applied to the first control electrode 32 during recording.
It is controlled by an electrical switching circuit 38 so that 37 are given respectively. Further, a switching circuit 40 controls the inductive electrode 22, the ion generating electrode 24, and the shielding electrode 25 so that an alternating current voltage 39 is applied during recording.

When recording a pixel, as shown in FIG. bias voltage Vb+ 37, and an alternating current voltage 39 is applied between the ion generating electrode 24, the shielding electrode 25, and the induction electrode 22, respectively. The ion generating electrode 24, the shielding electrode 25, and the induction electrode 2 are placed on both sides of the insulating layer 23.
By applying an alternating current voltage 39 between the electrodes 2, a corona discharge occurs at the periphery 43 of these electrodes, thereby generating ions.

The ion generation mechanism is as follows. When the alternating current voltage 39 between the electrodes 22 and 24 insulated by the insulating layer 23 is increased, ionization of gas molecules in the periphery occurs actively. That is, a small amount of ions always exist in the air, but when the electric field increases, the ions are accelerated and collide with gas molecules, ionizing them. When this ionization effect increases beyond a certain level, the insulating properties of the gas are lost and discharge occurs. As a result of this discharge, the surface of the dielectric material in the peripheral area becomes charged, so that the discharge eventually stops. On the other hand, a similar thing occurs when a reverse electric field is applied, in which case the dielectric surface is charged with ions of opposite polarity. By repeating this process, positive and negative ions are generated in the peripheral area.

The density of the ions thus generated depends on the voltage and frequency of the alternating current voltage 39, but the density is so high that it cannot be compared with conventional corona chargers (for example, 1
0-4 to 10-3 A/cm). In this embodiment, the AC voltage 39 is set to a voltage value of 1 to 3 kVP-P.
, the frequency was ~50kHz.

Here, since the control voltage Vc34 of about 60V is applied to the first control electrode 32, and the positive bias voltage Vb+37 of about 240V is applied to the ion generation electrode 24, the voltage of these electrodes 24, 32 is Due to the electric field E1 formed between the two, only positive ions are directed to the first control electrode 3.
Move to side 2. Next, the positive ions pass through a large number of ion passing holes 29 due to the electric field E2 formed by the control voltage Vc34 of approximately 60V applied between the first control electrode 32 and the second control electrode 33. It becomes possible to do so. Further, the surface of the dielectric layer 42 of the recording drum 1 is set to about -600V by the negative polarity corona ion generator 2 in advance.
Since the ions are uniformly charged, the positive ions that have passed through the ion passage hole 29 are accelerated toward the recording drum 1 by the electric field E3 formed by the negative ions.

The positive ions that have reached the surface of the dielectric layer 42 in this manner form an electrostatic latent image. When not recording a pixel, the contact of the switching circuit 35 is switched to the b side so that positive ions do not pass through the ion passage hole 29, and the first control electrode 32 and the second control electrode 33 are placed at the same potential ( (earth potential) and set the electric field E2 to 0. By doing so, the passage of positive ions is blocked. In this way, the ion flow passing through the ion passage hole 29 is controlled by switching the voltage applied between the first control electrode 32 and the second control electrode 33 from 0 to the control voltage Vc34 using the switching circuit 35.
This is done by switching between.

As described above, in the electrostatic recording device of this embodiment,
As mentioned above, whereas conventionally a control voltage of several hundred volts was required, control can now be performed with a voltage of several tens of volts. The reason why such low voltage control is possible is that in this embodiment, the width of the slit 26 is reduced to about 40 μm by further providing a shielding electrode 24 between the ion generation electrodes 24, and the AC for ion generation is The high voltage 39 is the control electrode 32,
The first reason is that it does not affect the electric field between 33 and 33. Furthermore, a dielectric recording medium (recording drum) is prepared in advance.
In this embodiment, the dielectric layer 42 on the surface of the recording medium 33 is first uniformly charged with negative ions, and + ions of opposite polarity are accelerated toward the recording medium 33 by an electric field formed by the negative ions. This is because the configuration is as follows.

Note that when the ion generator 20 and the control board 30 are integrated, it is necessary to optimize the distance between them using the spacer 28. By bringing the control board 30 closer to the ion generator 20, generated ions can be efficiently extracted. However, the electric field due to leakage of the AC voltage 39 applied to the ion generator 20
The closer it gets to 0, the larger it becomes. If the control board 30 is brought too close, the leakage electric field will be as large as the air ionization electric field (30k
V/cm), and spark discharge starts between the ion generator 20 and the first control electrode 32. Therefore, it is desirable not to bring the first control electrode 32 closer than the distance at which the magnitude of the leakage electric field is equal to or greater than the spark discharge starting electric field.

Furthermore, between each electric field E1, E2, E3, E
When used under the conditions of 3>E2>E1, a lens effect of the electric field occurs, which enables more efficient extraction of surrounding ions onto the recording medium and narrowing down of the ion beam to achieve higher definition. It becomes possible to form a pixel.

[0062] Furthermore, in order to obtain a stable recorded image,
It is desirable that the ratio of ions used for image recording to ions generated by the ion generator 20, in other words, ions passing through the ion passage hole 29, be small. In this embodiment, conditions are used such that this ratio is 0.5 or less.

According to the above embodiment, the space charge due to the high density ion current generated from the ion generator 20 is reduced to a low voltage (
High electrostatic contrast (350 V or higher) and high-speed recording (recording speed A4: 30 sheets/min) can be achieved by controlling the voltage at 80 V or lower. For this reason, in this example, the following points were taken into consideration.

(a) In order to obtain a high-density ion flow that enables high-speed recording, the ion generator 20 is provided with an induction electrode 22 and an ion generation electrode 24 with a dielectric layer 23 in between, and a high voltage ( 3
An alternating current voltage 39 of (kVP-P or less) is applied to generate high-density ions from the strong electric field region at the end of the ion generating electrode 24.

(b) The ion generation AC high voltage 39 is connected to the control electrode 32,
Ion generation electrode 2 so as not to affect the electric field between 33
4 is provided with a slit to block leakage of high electric field from the induction electrode 22 on the back surface.

(c) Pass ions through the air and apply high voltage (3kVP-
In order to attenuate the energy of ions generated in From control electrodes 32, 33
keep away from

(d) By precharging the recording medium 1 and forming an electric field for accelerating the ion flow, the control electrodes 32,
33 to facilitate the design of the drive circuit. In addition, an inverted electrostatic latent image is formed by precharging, making it possible to create an inverted image that is advantageous in terms of image quality, such as less density unevenness.

(e) In this way, the recording medium 1 is precharged to maintain the control electrodes 32 and 33 at a low potential, and the voltage amplification factor of the control electrodes 32 and 33 provided with the ion passage hole 29 is utilized. By making it possible to obtain high electrostatic contrast with a low control voltage, it is possible to use a low voltage driver IC with a low withstand voltage.

Next, we investigated the points (a) to (d) above from theoretical calculations, and conducted experiments to achieve low voltage control of ion current and high electrostatic charge using an ion flow recording head designed and prototyped from theoretical calculations. We will explain the results of studies regarding contrast, high speed, and the possibility of gradation recording.

First, extraction of the ion flow from the ion generator 20 will be explained.

Here, the phenomenon of ion generation when AC voltage is applied is experimentally grasped, and then the potential distribution of the ion generator 20 is determined by potential calculation using the boundary element method, and the critical voltage at which ions are generated and the ion generating electrode 24 are calculated. Predict the area where air will be ionized in the vicinity, and place an ion current measurement electrode (the first one) outside this area.
A control electrode 32) is provided to prevent spark discharge, and a control electrode 32) is provided to prevent spark discharge.
Determine the design parameters of the ion generator 20 that generates ions at an AC voltage 39 equal to or less than kVP-P. In addition, we determined a virtual surface where ions are generated infinitely from experiments on ion current, and made it possible to calculate and predict ion current using Poisson's equation, continuity equation for current, and equation for ion velocity in air based on ion mobility and electric field. .

(1) Ion generator 2 regarding the phenomenon of generation of bipolar ions
An alternating current voltage 39 is applied to the electrodes 22 and 24 sandwiching the zero insulator layer (glass) 23, and the phenomenon of ion generation is investigated. FIG. 5 shows the measurement system of the ion generator 20 used in the experiment.

In the experiment, 2.5 kV was applied to the ion generator 20.
P-P, applying an AC voltage 501 with a frequency of 3 kHz,
In addition, the distance to the ion current measuring electrode 502 is set to 500 μm, and the ion generating electrode 24 of the ion generator 20 is set to -50 μm.
A DC bias voltage 503 (same as 37) of 0 to +500V is applied. Further, the length of the ion current measuring electrode 502 is set to 1 cm, so that the calculated value per unit length and the experimental value can be directly compared. A corona discharge observation resistor 504 of 1 kΩ is added between the ion generating electrode 24 and the induction electrode 22, and the voltage waveform therebetween is observed with an oscilloscope or the like to measure the generated corona discharge. Further, a 100 kΩ resistor 505 for measuring ion current is added between the ion current measuring electrode 502 and the ground, and the polarity of flowing ions and current are observed from the voltage waveform.

The voltage waveform across the corona discharge observation resistor 504 is a waveform obtained by differentiating the applied voltage due to the capacitance between the induction electrode 22 and the ion generation electrode 24 and its resistance. Corona discharge occurs at approximately 500 V when the ion generating electrode 24 side has negative polarity (+ polarity when the induction electrode 22 side has positive polarity) and approximately 800 V when the ion generating electrode 24 side has positive polarity for 20 to 30 μs. Similar to the corona charger used in electrophotography, when the ion generating electrode side has negative polarity, corona discharge occurs at a smaller voltage. At this time, maximum 0.2~
A discharge current of about 0.3 mA/cm was observed.

[0075] When the frequency of AC voltage 501 is increased,
It was observed that the corona discharge time decreased approximately proportionally to the frequency, and at the same time, the ionic current increased approximately proportionally. For example, when the frequency is 30kHz, the discharge time is ~3μ
s, and the instantaneous maximum discharge current is 2 to 3 mA/cm. Therefore, the ion current measured by connecting the KETHLEY electrometer 610C that gives an average value of the current to the ion current measurement electrode increases with the frequency as the number of discharges increases. This situation is shown in FIG.

Next, 0V and +400V were applied as bias voltages 503 to the ion generation electrode 24, and the ion current flowing to the ion current measurement electrode was observed. Ion current is observed on the differential waveform of the AC voltage, and the bias voltage is 50
When 3 is 0V, the current is almost zero, and when it is +400V, a + current flows with the ± polarity of the AC voltage. Bias voltage 503 is 5
00V, the maximum ion current flowing through the current measurement resistor 505 observed with an oscilloscope is about 1 to 7% of the discharge current (0.2 to 0.3 mA/cm) generated at the ion generation electrode 24, which is ~2× 10-6 A/cm. Further, when the bias voltage 503 is -400V, -current is observed. In this way, a current determined by the polarity of the bias voltage flows every time the AC voltage is ±.

From the above, ions with ± polarity are generated by discharge, and the ions charge the insulator layer and lower the potential on the insulator layer, and the ions with polarity determined by the bias voltage are used to measure the ion current. It flowed to the electrode 502.

(2) Corona discharge starting voltage The parameters that determine the starting voltage of the ion generator 20 are (A) the thickness of the insulating layer 23, (B) the width of the slit 26 between the ion generating electrodes 24, and the width of the slit 26 between the ion generating electrodes 24. (C) There is an AC voltage 39 and a bias voltage 37 for ion generation. Here, from potential calculation using the boundary element method, we use the critical voltage at which corona discharge occurs in the ion generator to calculate 3kVP-P.
These parameters were determined so that corona discharge occurs below the AC voltage of . Furthermore, a region of 30 kV/cm or higher where spark discharge occurs between the ion generating electrode and the control electrode was determined, and an applied bias voltage range within that electric field was determined. Furthermore, the distance between the AC voltage 39 and bias voltage 37 was determined so that they could be designed independently.

The critical electric field at which this corona discharge occurs varies depending on the shape and surface condition of the ion generating electrode 24, and there is no theoretical calculation that is consistent with experiment. Therefore, we made the following assumptions and used the experimental formula for a corona charger.

[Approximation 1]: The potential distribution in the vicinity of the slit 26 of the ion generating electrode 24 where discharge occurs is almost the same as when the wire is replaced with a wire having a diameter equal to the thickness of the electrode, as shown in FIG. Therefore, the corona discharge starting electric field of the ion generator 20 is the corona charger's discharge starting electric field (
(see curve A in FIG. 8) is approximated using Cobin's empirical formula. However, in equation (1), a is the radius of the wire (cm
), m is a value determined by the wire surface and is approximately 1, and δ is the atmospheric pressure P
(cmHg) and temperature T (°C) are determined by equation (2). In addition, since the boundary element method used for potential calculation has large errors on the boundary, the following approximation was performed.

[Approximation 2]: When the discharge starting electric field on the wire is Ec, the electric field E at a position 5 μm away from the wire (see curve B in FIG. 8) is calculated from equation (3), and the electric field E of the ion generator 20 is When matched with the electric field 5 μm away from the ion generating electrode 24, Ec
is the discharge starting electric field of the ion generator 20. For example, the wire diameter (corresponding to the thickness of the corona ion generating electrode) is 20 μm.
For , the corona discharge initiation field on the wire is ~3×105
V/cm, and the electric field at a position 5 μm away at that time is ~1.6×10 5 V/cm. Therefore, it is assumed that discharge starts when the electric field at a position 5 μm away from the ion generating electrode 24 matches this electric field.

(A) Regarding determination of the thickness of the insulator layer 23 and the ion generating electrode 24 From potential distribution calculations with the thickness of the insulator layer 23 changed to 40, 20, and 10 μm, it was found that the slit 26 of the ion generating electrode 24 Corona discharge starting electric field (~1.6×105 V/
9(a), (b), (
c) and 3×104 V/, where ionization occurs in air.
The electric field area in cm was determined. At this time, the width of the slit 26 is 40 μm, the thickness of the ion generating electrode 24 is 20 μm, the AC peak voltage is 1.5 kV (3 kVP-P), and the bias voltage is 400 V. In addition, the insulator layer 23 used in the calculation
The induction factor εi was set to 3.5.

When the thickness of the insulating layer 23 is as thick as 40 μm, no discharge occurs even at a peak voltage of 1.5 kV. Further, when the thickness of the insulating layer 23 is reduced to 20 or 10 μm, corona discharge occurs almost throughout the entire thickness of the ion generating electrode 24. At this time, the alternating current voltage at which the discharge starting electric field occurs at the boundary between the ion generating electrode 24 and the insulating layer 23 (a point 5 μm apart in calculation), which has the strongest electric field, is determined by the thickness of the insulating layer 23 as shown in FIG. 1.8k when the diameter is 40μm
V, 900 V at 20 μm, and 600 V at 10 μm. In this way, the thinner the insulator layer 23 is, the more the ion generating electrode 2
The electric field near 4 becomes large, and a large amount of ions can be generated with a low AC voltage. In the experiment, the thickness was set to 20 μm based on the withstand voltage of the thick film printed glass layer used as the insulator layer 23.

[0084] Also, 30kV where ionization occurs in the air
/cm at the center of the insulator layer 23 above the slit 26 of the ion generator 20 for each insulator layer 23 thickness.
It reaches up to 20 μm, 40 μm, and 50 μm. In order to prevent spark discharge, it is necessary to separate the ion current measuring electrode (or first control electrode 32) by more than this distance. The mean free path of molecules in air is ~0.06 μm, and it is considered that the energy of ions is sufficiently attenuated at a distance of several tens of μm from the ionization region.

(a) Determination of the slit width between the ion generating electrodes Next, the width of the slit 26 between the ion generating electrodes 24 is set to 40,6
0.80 μm, the discharge starting electric field and the region where ionization in the air occurs were determined as shown in FIG. 11, and the optimum slit width was determined. The corona discharge starting voltage at this time decreases to 900V, 700V, and 630V as the width of the slit 26 increases as shown in FIG. 12, the leakage electric field from the slit 26 increases and discharge becomes easier. When an ion generation voltage with a peak voltage of 1.5 kV is applied, the region where the discharge starting voltage is applied exists up to the vicinity of the thickness of the electrode, but the change due to the width of the slit 26 is small. On the other hand, when the slit width is 40 μm and the ionization region is 60 μm above the insulator layer, when the slit width is 60 μm and the slit width is 70 μm, and when the slit width is 80 μm, the leakage electric field from the induction electrode 22 increases rapidly and increases to nearly 130 μm.

As described above, although the leakage electric field that determines the ionization region increases with the slit width, there is no significant change in the firing voltage. Therefore, it is preferable that the slit width be small. Table 1 shows preferred specifications of the ion generator determined from the above conditions.

(c) Regarding ion generation voltage and bias voltage Next, the distance between the ion generator 20 and the ion current measurement electrode 502 is set to 10
A separation of 0 μm or more indicates that the AC voltage 501 and bias voltage 503 applied to the ion generator 20 can be set independently. The specifications of the ion generator used in the calculations are as shown in Table 1.

Bias voltage 5 is applied to the ion current measurement electrode 502.
Potential distribution at the center of the ion generator 20 when an AC voltage 501 of 03-400V and a peak of 1.5kV (3kVP-P) is applied to the ion generator 20, and the AC voltage 501 is further changed to 1kV and 750V. was calculated using the boundary element method. The relationship between the applied voltage and potential distribution at this time is shown in FIG. The potential becomes almost zero in the vicinity of 60 μm above the insulator layer 23 of the ion generator 20, and decreases at a substantially constant value determined by the bias voltage 503 at a distance beyond that. This distance is also the limit of the region in which ionization in the air occurs.

On the other hand, the peak voltage of the AC voltage applied to the ion generator 20 is set to 1.5 kV, and the ion generating electrode 24
The voltage of the ion current measuring electrode 502 is -250
, -400, -800, -1200V, the potential distribution is as shown in FIG.
Regardless of the size of 03, the potential becomes almost zero at a distance of 60 μm in front of the insulator layer 23, and decreases at a constant rate determined by the bias voltage 503 at a distance beyond that. Like this, 60
By providing the ion generator 20 and the ion current measuring electrode 502 at a distance of at least μm, the alternating current voltage 501 and bias voltage 503 for ion generation can be set independently.

Next, using the ion generator 20 with the specifications shown in Table 1 used in the experiment, the amount of ion current flowing through the ion current measuring electrode 502 when the distance from the ion current measuring electrode 502 is set to 500 μm is calculated using Poisson's equation. , is theoretically predicted from the continuity equation of current and the ion velocity equation caused by ion mobility and electric field. The speed of ions is proportional to the electric field.

Next, the calculation procedure and its outline will be described. Assuming that the charge density of ions existing at a distance y from the ion generator 20 is ρ, the voltage at that point is Vy, and the ion current is Iy, the relation between voltage and ion current is the Poisson equation of equation (4), and the current is It can be expressed by a continuity equation and an ion velocity equation when an electric field is applied. Here, the distance y is assumed to be based on the ion generation electrode 24 of the ion generator 20, and the bias voltage 502 is applied between this reference point and the ion current measurement electrode 502. εo is the dielectric constant in vacuum, εa is the relative dielectric constant of air, μ is the ion mobility in air, and υ is the speed of the ions.

As a result of this calculation, the ion current Iy at the distance y from the insulator layer 23 in the direction of the ion current measuring electrode is:
It is shown by equation (5). Here, the value of yo can be determined from the experimental value of the ion current value Ib flowing through the ion current measurement electrode 502 when the bias voltage Vb is applied. The physical meaning of yo is a virtual ion generation surface where the initial ion velocity is zero and an infinite number of ions exist. Once the value of yo is determined from experimental ion current measurements, the ion current can be calculated for any given bias voltage. Therefore, next, the value of this yo is determined from the experimental value of the ion current.

If the distance between the reference plane and the ion current measuring electrode is L1, then from equation (5), the ion current value I flowing through the ion current measuring electrode when bias voltage Vb is applied is
b can be expressed by equation (6). From this result, y
o can be calculated using equation (7) using the measured value Ib of the ion current.

In the above calculation of the ion current, + polar ions were treated. For -polar ions, the polarity is reversed and the +polar mobility (μ+ = 1.4cm2 /Vs
ec) instead of −polar ion mobility (μ− = 1
．． 9cm2/Vsec) may be used.

Next, KEITHL gives the average value of the current.
Using a Y electrometer 610C, an ion current measurement test is performed and compared with the calculated results. Bias voltage Vb
When the ion current Ib is measured by changing the ion current Ib, the ion current is proportional to the square of the bias voltage, as shown in FIG. 15, and coincides with (6) of the ion current. yo for this experimental result
When the value is calculated from (7), it becomes equation (8). In other words,
212 μm behind the insulator layer 23 of the ion generator 20 is
It becomes a virtual theoretical ion generation surface.

On the other hand, when the frequency is increased to increase the amount of ions generated, the ion current becomes saturated. At this time, the value of yo causes the virtual plane to slightly approach the reference plane as shown in FIG. Next, calculate the frequency at which this ion current saturates. The saturated ion current value Im at which the value of yo becomes zero is obtained by applying an alternating current voltage (frequency 30 kHz) to the corona ion generator, bias voltage Vb (500 V), and distance L1 from the reference point (
The relational expression (
It can be expressed by equations 6) to (9).

[0097] Furthermore, if the frequency is calculated by multiplying 30 kHz by 3.7 using the above-mentioned results shown in FIG. 6 in which the frequency and the ion current are proportional, it becomes ~100 kHz. At a frequency higher than this, the space charge of the generated ions suppresses the generation of ions, and the ion current cannot be increased any further. Therefore, to further increase the ion current, it is necessary to increase the bias voltage, but the upper limit of the bias voltage at which spark discharge does not occur determines the limit of the ion current in the presence of space charges. Therefore, there is a speed limit to a low-voltage driven ion flow recording head that utilizes this space charge.

On the other hand, 30k applied to the ion generator 20
If you change the value of AC voltage 39 in Hz, it will be 1.6kVP-P.
An ion current is generated at 1.8 kVP-P or above, and no large increase in ion current occurs (see FIG. 17). This indicates that the ionic current generated by the ~4 μs discharge every half cycle of the AC voltage 39 has reached saturation. This discharge time is approximately 1/4 of a half period of the AC voltage, so the instantaneous value of the ion current is approximately 4 times this average current, 2.6×
It becomes 10-6A/cm. Since this almost coincides with the saturated ion current, it is considered that the ion current has reached saturation.

Next, low voltage control of the ion flow recording head 2 will be described.

[0100] Here, the above-mentioned ion flow recording head 2 will be described.
From the distribution calculation using the boundary element method when applying a low control voltage between the control electrodes 32 and 33, it is possible to control the ions at a low voltage, and from the calculation of the ion current using the voltage amplification effect of a tetrode vacuum tube as a model, It is shown that a latent image with a high electrostatic contrast of several hundred volts can be formed with a low control voltage.

First, low voltage control prediction by potential distribution analysis using the boundary element method will be described. Here, the potential between the ion generator 20 of the ion flow recording head and the recording medium 1 is calculated using the boundary element method, and a low voltage is applied between the control electrodes 32 and 33 to prevent ion movement. This shows that it is possible to generate a reverse electric field. Table 2 shows the applied voltages used in the calculations.

The thickness of the insulator layer 23 of the ion generator 20 is 20 μm, the thickness of the electrodes 24 and 25 is 20 μm, the width of the ion generating electrode 24 and the slit 26 is 40 μm each, and the three ion generating electrodes 24 and It has two slits 26. Potential calculations were performed for the case where the slit 26 and the ion passing holes 29 of the control electrodes 32 and 33 coincided, and the case where the ion generating electrode 24 coincided, and the required precision at the time of head prototype production was examined. In addition, the ion generator 20 and the first control electrode 3
The distance to the two surfaces is 460 μm, the thickness of the insulating substrate 31 between the first and second control electrodes 32 and 33 is 100 μm,
The distance between the second control electrode 33 surface and the recording medium 1 is 500μ
It is m. The thickness of the first control electrode 32 is 18 μm, and the thickness of the second control electrode 32 is 18 μm.
The thickness of the control electrode 33 was set to 48 μm, including a certain amount of burr, since the hole in the head was made with a drill. Also,
Ion passage holes 2 of first and second control electrodes 32, 33
9 has a diameter of 100 μm, which corresponds to a resolution of 10 lines/mm.

The voltage arrangement of the ion flow recording head 3 is such that the peak value of the AC voltage 39 applied to the ion generator 20 is
．． 5kV (3kVP-P), and the ion generation electrode 24
The bias voltage 37 was set to 250V, the bias voltage 34 applied to the first control electrode 32 was set to a variable voltage of (-20 to 60)V, and the second control electrode 33 was set to ground potential. Also,
The surface potential of the recording medium 1 was set to -600V. The calculation was performed at the center of the ion passage hole 29 where the influence of the applied voltage on the control electrodes 32 and 33 is the smallest.

FIG. 18 shows this situation. The potential shown by the solid line near the ion generator 20 in the figure is the potential of the ion generator 2
This is the case where the centers of the 0 slit 26 and the ion passing holes 29 of the control electrodes 32 and 33 coincide, and the dotted line shows the case where the centers of the ion generating electrode 24 coincide. Ion generator 20
100 .mu.m in front of the insulator layer 23, both have substantially the same potential, and do not affect the potential difference between the control electrodes 32 and 33. Further, in the figure, the potential distribution near the control electrode 33 is shown in an enlarged manner. When a voltage of 60V is applied to the first control electrode 32, a distribution in which the potential always decreases,
The + polar ions move toward the recording medium 1 and lower its surface potential. The potential of the first control electrode 32 is −20
When the voltage reaches V, the potential relationship between the first and second control electrodes 32 and 33 is reversed, and a reverse electric field is generated to block + polar ions. As described above, it is predicted that in the ion flow recording head 3 of this embodiment, the ion flow can be controlled with a low control voltage.

Next, by applying the voltage amplification factor, which has been studied in detail for vacuum tubes, to the ion current, we can replace (A) the equation for the movement of electrons in the vacuum tube with the equation for the velocity of the ions moving in the electric field, and Find the ion current that can be controlled by voltage. Furthermore, using this calculation method, it will be shown that (B) the ion current reaching the recording medium is stable, similar to a vacuum tube, even when the amount of ions generated by the ion generator fluctuates greatly (50%).

(A) About ion current that can be controlled at low voltage As with vacuum tubes, any point on the virtual control surface is placed on the surface of the ion passage hole 29 at the center of the thickness of the first and second control electrodes 32 and 33. Calculate the potential distribution at . This calculation uses a voltage amplification factor that can be calculated from the mutual capacitance of the electrodes. Next, using Poisson's equation, the continuity equation of current, and the ion velocity equation based on ion mobility and electric field, a space charge due to the ion current is determined from the potential on the virtual control surface at the first and second control electrodes 32 and 33. Recording medium 1 when
Calculate the ionic current that reaches . The calculation was performed by changing the voltage of the first control electrode 32, and the experimental value of the prototype ion generator 20 was used for the ion current. Furthermore, the rate at which the ion current enters the ion passage hole 29 of the first control electrode 32 is determined by approximating the correction term by the electric field list effect vacuum tube.

[0107] Head used for this calculation and recording medium 1
The parameters of are shown with reference to FIG. The distance from the surface 60 μm in front of the insulator layer 23 of the ion generator 20, where the potential is zero, to the virtual control surface of the first control electrode 32 is L1.
, the distance between the virtual control surfaces of the first and second control electrodes 32 and 33 is L2, the distance between the virtual control surface of the second control electrode 33 and the recording medium 1 is LP, the thickness of the first control electrode 32 The thickness of the second control electrode 33 is 2.G2.
shall be. In addition, the first and second control electrodes 32, 33
The sum of the thickness of the control electrode 32 and the diameter of the ion passage hole 29
, 33 periods P1 and P2. Calculation is thickness 2・G
It is approximated by assuming that the control electrodes 32 and 33 of 1 and 2·G2 are continuous with periods P1 and P2, similar to the grid of a vacuum tube.

The first control electrode 32 has Vg1, the second control electrode 33 has Vg2, and the surface potential of the recording medium 1 has Vp.
When Ip is applied, the ion current generated by the ion generator 20 is controlled by the first and second control electrodes 32 and 33, and an ion current Ip flows through the recording medium 1. The control voltage Vg1 of the first control electrode 32 is applied to the distance L0 between the ion generating electrode 24 and the first control electrode 32, and the first
When the potential on the virtual control surface of the control electrode 32 becomes VG1, the ionic current IG1 becomes the value shown by the equation (10) as shown by the equation (5).

Here, in calculating the potential VG1, a triode consisting of the ion generator 20 and the first and second control electrodes 32 and 33 is assumed, and the virtual ion passage hole 29 of the first control electrode 32 is Let K1 be the voltage amplification factor at any point on the control surface. The value of this amplification factor K1 is determined only by the capacitance between the electrodes. Similarly, the amplification factor of the triode vacuum tube consisting of the first and second control electrodes 32 and 33 and the recording medium 1 is K2, and the first and second control electrodes 3
The mutual amplification factor between the ion generator 20, the first and second control electrodes 32, 33, and the recording medium 1 is Kp.

These amplification factors are a function of the location on the virtual control surface, but here, the center point of the ion passage hole 29 is representatively calculated. At this time, the potential VG1 at any point on the virtual control surface of the first control electrode 32 is expressed by equation (11). Further, the mutual amplification factors K1 to K2 and Kp can be expressed as in equation (12) using the amplification factors K1 and K2 of the triode vacuum tube.

Of the ion current IG1 flowing on the virtual electrode surface of the first control electrode 32, the ion currents I1-2 that pass through the ion passage hole 29 of this control electrode 32 and reach the second control electrode 33 are A correction term Sg1 for the shielding rate of the vacuum tube is introduced and approximated by the geometric shielding rate S1 of the control electrode 32 of 1 and a correction term N1 that takes into account the electric field concentration effect due to the electric field, and can be expressed by the following equation.

I1 ~ 2 = Sg1 · IG1 S1 in the ion flow recording head 3 is the first control electrode 32 with a diameter of 18 μm and the ion passage hole 29 with a diameter of 100 μm.
Since it is determined with a period of 118 μm, the value is 0.85. The ion current passing through the ion passage hole 29 of the first control electrode 32 is controlled by the second control electrode 33. First and second control electrodes 32,3
Using the amplification factor K2 of the triode vacuum tube consisting of 3 and the recording medium 1, the potential VG2 on the virtual plane of the second control electrode 33 is expressed as follows. It becomes as shown in equation (13).

The ion current IG2 flowing on the virtual electrode surface of the second control electrode 33 can be calculated by using the potentials VG1 and VG2 on the virtual control surfaces of the first and second control electrodes 32 and 33, as shown in (14). It is given by Eq. here,
y1 is a virtual plane assuming that the ion currents I1 to 2 that have passed through the ion passage holes 29 of the first control electrode 32 are the ion generation sources. y1 is the distance from the reference point,
It can be expressed by equation (15).

Of the ion current reaching the second control electrode 33, the ion current Ip passing through the ion passage hole 29 of the second control electrode 33 and reaching the recording medium surface is similarly A correction term Sg2 for the shielding rate is introduced that takes into account the shielding rate S2 and the correction term N2 for the electric field concentration effect due to the electric field, and can be expressed by equation (16).

The correction term S2 in the head is 48 μm
A second control electrode 33 with a diameter of 100 μm and an ion passage hole 2 with a diameter of 100 μm.
It is assumed that they exist at intervals of 148 μm consisting of 9, and the value is 0.68. As a result, the ion current reaching the recording medium 1 per unit length of the head having the ion passage hole 29 with the diameter Rd is expressed by equation (17).

Next, the control voltage applied to the first control electrode 32 is changed, and the ion current per unit length reaching the recording medium 1 is calculated (see FIG. 20). The parameters to be calculated are set in Table 2 so that the potential distribution is the same as in the ionic current experiment shown in FIG. 21. In an actual low voltage drive experiment, the second control electrode 33 was set to ground potential, the ion generating electrode 24 of the ion generator 20 was applied a bias voltage 314 of 250 V, and the recording medium 1 was applied a surface potential of -600 V. Apply it by charging. Control voltage Vg in the diagram
1 is converted to the voltage when the second control electrode 33 is at ground potential.

[0117] When the voltage of the first control electrode 32 is -10V, a cutoff state occurs and the ionic current stops. This value almost matches the voltage when a reverse electric field is generated between the control electrodes using the boundary element method (see FIG. 18). As the control voltage increases, the ion current increases, and at a voltage of 60 V, the ion current reaches a maximum value of 1.4 x 10-8 A/cm. Furthermore, when the control voltage is increased, the bias voltage between the first control electrode 32 and the ion generator 20 is decreased, and the ion current is also decreased. The ion current also becomes zero at 33V, when the control voltage becomes approximately the same as the bias voltage.

Next, using the ion current recording head used in the calculation, an ion current measurement system (
(see FIG. 21), the change in the ion current value with respect to the control voltage is measured. This measurement system connects a KETHKEY microcurrent meter to an electrode for measuring ion current, and
A head is provided at m. The second control electrode 33 is set to 600 V, which is equal to the surface potential of the recording medium 1 by precharging, so that a minute current can be measured. The first control electrode 32 that provides a pulse voltage for low voltage control has a continuous pulse with a pulse width of 10 msec (corresponding to a recording speed of 40 sheets/min) and a duty of 1/2, which is variable from -100 to +400 V. is applied superimposed on 600V. An alternating current voltage of 30 kVP-P was applied to the ion generator 20, and a pulse voltage of 29 V and 60 V was applied to the ion generating electrode 24 and the second control electrode 33, respectively. 910V, which is a bias voltage of 250V, is applied. Since the duty of the pulse voltage is 1/2, the measured value of the microammeter is doubled and compared with the calculated value. When the dynamic characteristics of the ion current recording head were measured in this way, the calculated value of the ion current (see FIG. 20) almost matched the actually measured value.

(B) Changes in controlled ion current due to fluctuations in ion generation amount Next, when the ion generation amount fluctuates, the amount of fluctuation in the ion current controlled by low voltage drive is determined, and the stability of the low voltage drive method is determined. Confirm the properties from theoretical calculations. Such fluctuations in the amount of ion generation occur due to non-uniformity of the ion generation electrode of the actual head or deterioration of the ion generator 20. In equation (5) giving the ion current, the ion current Io at distance y=o
It can be seen from equation (4) that ρ is proportional to the amount of ions ρ generated.

Next, while keeping the applied voltage Vy constant, the change Δyo in the virtual surface yo when the ion amount varies ΔIo is expressed as (1
8) Calculate from formula. The amount of variation in this virtual surface Δyo is given by equation (19) using the amount of ion current variation ΔIo. For example, using the above-mentioned ion generator 20, 30kHz
, when the bias voltage is 500V, yo=2.72×1
It is 0-2 cm. Using this value, increase the amount of ions generated by 50
% increase, Δyo will vary by about 14%. This value is such that yo is 0.34×10 −2 cm close to the insulator layer 23 of the ion generator 20 . When there is a change in the amount of ions, the amount of change ΔIb in the ion current Ib flowing into the electrode at the distance L1 is given by equation (20).

From the above equation, the variation amount Δ of the ion current Ib
Ib takes a value as shown in equation (21). For example, as shown in Fig. 6, the frequency is 30kHz, the applied voltage is 2.0kVP
-P and the ion current is 6.5 x 10-7 A/cm, if the amount of ions generated is increased by 50%, the fluctuation ΔIb of the ion current Ib flowing to the ion current measurement electrode 502 500 μm away increases by 14%, 7.4×10-7A/cm
becomes. In this way, when a space charge exists, the ion current decreases to about 14% variation compared to 50% variation in ion amount.

Furthermore, when the amount of ions generated fluctuates by 50%, the ion current using the low voltage control recording head is shown in FIG.
The trial calculation was made as 0. When the control voltage is 60V, the current reaching the recording medium 1 is 1.32 x 10-8 A/cm to 1
．． Increases to 43 x 10-8 A/cm. However, the amount of variation is about 8% and is decreasing further. Furthermore, when the control voltage is 60V or less, the amount of variation becomes even smaller.

[0123] In the conventional method in which the high voltage of AC high frequency is switched for each image point to control on/off of the corona discharge and all the generated ions are used, fluctuations in the amount of ions generated directly appear in the image quality. However, with this method, which uses a low-voltage driven ion flow recording head and controls the space charge of ions, it is possible to obtain a stable electron flow even with fluctuations in electron emission from the cathode of a vacuum tube. It is possible to reduce large fluctuations in the amount of ions generated to 8% or less. As described above, calculations predict that stable recording can be performed using this low-voltage driven ion flow recording head.

Next, the ion current is measured using this ion current recording head and the ion current measurement system. Further, an ion current is applied to the precharged recording medium 1 with a surface potential of 600 V, and the attenuation of the surface potential at that time is calculated to determine the electrostatic contrast. Furthermore, a 50 μm thick Mylar film (Lumira) with conductive treatment on the back side was added to the recording medium 1.
A dielectric layer is used to create an electrostatic latent image that is attached to the ionic current measurement electrode 502, and development is performed using a two-component developer to form image dots. In this way, it is confirmed that the ion current can be controlled with low voltage using the recording head.

First, using the ion current measurement system shown in FIG.
The ion current is measured by placing the ion current close to 50 μm. Further, a continuous pulse of 10 msec with a duty of 1/2 is applied to the first control electrode, and the ion current is measured.

FIG. 22(a) shows the calculated and measured values of the ion current when the pulse voltage is changed using the above measurement system. The calculated value (solid line) and the measured value (broken line) match, and when the voltage applied to the first control electrode 32 is 60 V, it is close to the maximum value ~1.9×
An ionic current of 10-8 A/cm is obtained. This current value is 500% between the head 1 and the ion current measuring electrode 502.
This is almost twice as much as in μm. Further, when this pulse voltage is increased, the bias voltage between the first control electrode 32 and the ion generation electrode 24 is decreased, and the ion current is decreased. When the control voltage equals the bias voltage, the ion current becomes approximately zero. From experiments using the recording head described above, it was confirmed that the ion flow could be controlled by applying a low pulse voltage of about 60 V to the first control electrode 32.

Next, a 50 μm thick Lumira is provided on the recording medium 1, precharged to 600 V, and the electrostatic contrast of the electrostatic latent image when ion flow is irradiated is calculated. When the ion current Ipo per unit area reaches the recording medium 1 with relative dielectric constant εi and thickness di, 60
The surface potential on the recording medium 1 at 0V decreases, and an electrostatic latent image is formed. The decrease in the amount of charge on the recording medium 1 due to this decrease in surface potential ΔVp is equal to the amount of charge when the ion current Ipo flows for a time of Δt. The amount of variation ΔVp in the surface potential on the recording medium 1 can be calculated by using the capacitance Co (=εo·εi/di) per unit area of the recording medium 1.
2) It can be expressed by the formula.

When the ion current Ipo controlled by the ion current recording head is used to integrate the equation (22), and the surface potential Vp is expressed as a function of time, the equation (23) is obtained. Here, Vs is the surface potential of the recording medium due to precharging, and the coefficients AA, KK1, KK2, and KK3 are values determined by the amplification factor and the dimensions of the head. Taking the pulse width T applied to the head as a parameter, T = 4ms
ec (recording speed 5 sheets/min: equivalent to A4), T = 2msec
(recording speed 10 sheets/min), T=1 msec (recording speed 2
0 sheets/min) and T=0.5 msec (recording speed of 40 sheets/min), the attenuation of the surface potential with respect to the pulse voltage was calculated. This situation is shown in FIG. 22(b). The calculation was performed using the dielectric constant of the Mylar recording medium 1 of 2.3. When the pulse voltage is 60V (arrow in the figure), a high electrostatic contrast of 480V can be obtained with a pulse width of 4 msec. Also, T
= 29V for T = 2msec, 270V for T = 1msec
, and it can be predicted from the calculation that an electrostatic contrast of 90 V will be obtained at T=0.5 msec.

Next, the ion current measurement electrode 5 of this measurement system
Lumira recording medium 1 was attached to 02, and ion current was irradiated to form an electrostatic latent image using a two-component developer to form image points. In this way, the head is brought close to the recording medium 1, and there are If the ratio of each electric field is 4:2:1,
The trajectory of ions passing between the control electrodes 32 and 33 is shown in FIG.
As shown in 3, it can be predicted that the number will be narrowed down without expanding. Here, the potential calculation was performed using the boundary element method, and the trajectory was drawn assuming that the ion moves in the electric field direction perpendicular to the equipotential surface. As a result, an electrostatic latent image with high electrostatic contrast was obtained on the recording medium 1, and good image dot formation was achieved.

[0130] In the print sample, the pulse width is 4 msec.
The ion passage hole 2 of the control electrode becomes a picture point of 170 μmφ.
9 (100 μmφ), but at 2 msec, the pixel size is 97 μmφ and is almost the same as the ion passage hole 29. At 1msec, it becomes less than 58μmφ, and at 0.5msec
In c, the size of the image dot further decreases to 40 μmφ. Furthermore, as the pulse width decreases, the image density also decreases. This means that the ion current is maximum at the center of the ion passage hole 29,
This is because the electrostatic contrast becomes the largest. Therefore, as the pulse width becomes smaller and the electrostatic contrast decreases, the image dot also becomes smaller. In this way, by changing the pulse width, it is possible to change the diameter and density of the image dot, and gradation recording can be performed by controlling the pulse width. From the above experimental results,
It has become clear that gradation recording can be performed by controlling the ion current by applying a pulse voltage of 60 V to the first control electrode 32 using the head 1, and by changing the pulse width.

Next, speed limit prediction using ion current will be explained. Factors that determine the recording speed of the head include the travel time of ions and the amount of ions that reach the recording medium 1. Here, (1) ion travel time and (2) recording medium 1
The amount of ions reached is calculated and the limit of recording speed due to low voltage control is predicted.

(1) Travel time of ions Ions generated within a range of 60 μm from the front of the insulator layer 23 of the ion generator 20 are transported through the slit 2 of the ion generating electrode 24
It moves at high speed due to the leakage electric field caused by the AC voltage from 6, and reaches a reference point where the potential becomes zero. Next, the time required for the ions to pass through this range of 60 μm in front is calculated. 1.5kV
When a voltage of is applied to the ion generator 20, the electric field (see FIG. 18) becomes the weakest at 60 μm in front of the insulator layer 23, and this electric field has a value shown by equation (24).

Now, using the +polar ion mobility μ+ in air = 1.4 cm2 /V·sec, and finding the time it takes to travel ~60 μm in this electric field, which is the smallest in this range, we can obtain the following equation (25). It will look like this. In addition, for -polar ions, μ- = 1.9 cm2 /V・se
Calculations can be made using c. This time is 14MH
It can be seen that the generated ions immediately pass through this range. Furthermore, even when applying an AC voltage at a high frequency of 110 kHz, which maximizes the amount of ions generated, ions pass through this region before the polarity of the AC voltage changes.

Next, the ion transit time between the ion generator 20 and the first control electrode 32 is calculated. During this time, the electric field generated by the DC bias voltage of 250 V becomes the smallest when a signal voltage of 60 V is applied to the first control electrode 32, and the electric field has a value expressed by the following equation. Eb=190V/0.04cm=4750(V/cm)
In this electric field, the front of the insulator layer 23 of the ion generator 32 ~ 60
The ion transit time tg1 from μm to 450 μm to reach the first control electrode 32 is expressed by equation (26). This running time is a recording time of 0.5 msec (recording speed approximately 4
This corresponds to ~1/80 of the speed (equivalent to 0 sheets/min), and does not impose a speed limit.

Furthermore, if the signal voltage is turned off before the ions pass through the second control electrode 33 and the electric field between the first and second control electrodes 32 and 33 is reversed, the ions will pass through the second control electrode 33.
can no longer pass through the control electrode 33. Therefore, the ion transit time between the first and second control electrodes 32 and 33 is calculated next. When 60V is applied to the first control electrode 32, the electric field between the first and second control electrodes 32 and 33 is expressed by equation (27). At this time, the time for ions to pass between the control electrodes is expressed by equation (28). The ion travel time during this period is ~1/360 of the recording time of 0.5 msec.
and does not impose a speed limit.

[0136] Furthermore, the ions that have passed through the second control electrode 33 have a surface potential 600 of the precharged recording medium 1.
The constant electric field caused by V reaches the recording medium 1. Second
The travel time of ions between the control electrode 33 and the recording medium 1 is shown below. The electric field between the second control electrode 33 and the recording medium 1 generated by this 600V surface potential on the recording medium 1 is (
29). Therefore, the traveling time of ions between the second control electrode 33 and the recording medium 1 has the value of equation (30). This running time is ~1/170 of the recording time of 0.5 msec (equivalent to 40 sheets/minute). From the above calculations, the total ion transit time T is expressed as equation (31), and the recording speed is 0.5
This corresponds to ~1/50 of msec. Therefore, the total traveling time of ions becomes approximately the same as the recording time only when the recording speed corresponds to 1700 sheets/min. From the above, the recording speed of ion position recording is not limited by the ion travel time.

(2) Regarding the speed limit based on the amount of ions reaching the recording medium As described above, the ion travel time does not affect the recording speed. The limit of the recording speed is determined by the amount of ions that reach the recording medium 1, and this amount of ions is determined by the amount of ions generated in the ion generator 20 and the amount that reaches the first control electrode 32. In order to increase the amount of ions generated, it is necessary to increase the amount of ions by the ion generator 20 or to increase the amount of ions generated by the first control electrode 32.
In order to increase the amount of ions reaching
0 and the first control electrode 32 , and the distance between the ion generator 20 and the first control electrode 32 approaches.

First, the frequency of the AC voltage applied to the ion generator 20 is set to 110k, at which the amount of ions reaches the maximum saturation value.
Set the frequency above Hz. Next, the ion generator 20 and the first control electrode 32 are brought close to each other within a range where spark discharge does not occur, and the bias voltage is increased as much as possible to predict the upper limit of the recording speed. The irradiation time is determined from Equation (16) of the ion current that gives the electrostatic contrast (~350 V or more) on the recording medium 1 necessary for the development at that time, and Equation (23) that gives the potential attenuation.

[0139] Furthermore, when an ion current is applied to the recording medium 1 (mylar sheet) with a thickness of 50 μm, a dielectric constant of 2.3, and a surface potential of 600 V, using the ion irradiation time as a parameter, the surface of the recording medium 1 The potential is a control voltage of 60 V with a pulse width of 4 to 2 msec (recording speed of 5 to 10 sheets/min), and the electrostatic contrast is a maximum potential of 600 V, and 460 V at 1 msec (recording speed of 20 sheets/min), and further 0.5 msec ( At a recording speed of 40 sheets/min), the voltage is 280V.

[0140] Next, such a saturation frequency of 110kHz,
An alternating current voltage of 2.5 kVP-P is applied to the ion generator 20, and the first control electrode 32 is connected to a distance of 100 μm where an electric field of 30 kV/cm or less does not cause forward spark discharge of the ion generator 20. The ion current reaching the recording medium 1 was determined with respect to the control voltage while the distance was brought close and the bias voltage was increased to 250 V (see arrow in FIG. 14) at which spark discharge does not occur. This is shown in FIG. 25(a). In addition, the attenuation of the surface potential was calculated using the pulse width of the control voltage as a parameter. This is shown in FIG. 25(b).

[0141] Cutoff voltage at which ionic current begins to flow -
When 60V is applied to the first control electrode 32 based on 60V, the surface potential of the recording medium 1 becomes almost zero when the pulse width of the control voltage is 0.5 msec (recording speed 40 sheets/min), and the electrostatic contrast is the maximum potential of 600V. Further, at 0.2 msec (recording speed of 100 sheets/min), the electrostatic contrast can be 330V. At this time, if the control voltage is set to 80V, the electrostatic contrast can be increased to 480V. As described above, the recording speed of this method using space charges that can be controlled at 80 V is calculated to be 100 sheets/min.

As described above, using the above-mentioned ion flow recording head, the ion generator 20 has 2.5 kVP-P, 30
By applying an alternating current voltage of kHz, applying a bias voltage of 250 V to the ion generator 20, and precharging the surface potential of the recording medium 1 to 600 V, it becomes possible to control ions with a control voltage as low as 60 V. High electrostatic contrast (550V) can be obtained. The calculated value of the ion current, taking into account the voltage amplification factor similar to that of the vacuum tube described above, almost agrees with the experimental value, making it possible to realize a low-voltage controlled ion flow recording head. In addition, by changing the pulse width of the control voltage applied to the control electrode to form actual electrostatic latent image dots on a Mylar sheet and developing them to create recording dots, gradation recording was possible. Because high electrostatic contrast can be obtained in this way, unlike conventional methods that control ion current, there is no need to use magnetic component developers for low electrostatic contrast.
It is now possible to use developers commonly used in electrophotography.

On the other hand, calculations of electrostatic contrast when increasing the ion current show that high-speed recording of up to 100 sheets/min is possible with low voltage control, and that the amount of ions generated can be increased by 50
% variation, it can be predicted from calculation that the variation in ion current can be suppressed to 8% or less. Unlike the conventional method which uses all the ions generated in this way, it is possible to record stably even against temporal deterioration fluctuations in the amount of ions generated and non-uniformity of the amount of ions generated for each image point.

Next, a more specific configuration of the ion flow recording head 3 based on the above recording principle will be explained in detail. FIG. 26 is a sectional view of the ion flow recording head 3, and FIG. 27 is a side view.

As shown in FIG. 26, this ion flow recording head 3 is composed of a head support 100, an ion generator 20 supported by this support 100, a control board 30, and a drive circuit board 103. , ion generator 20
, the control board 30 and the drive circuit board 103 are removable together with the head support 100. The ion generator 20 and the control board 30 have a structure as shown in FIG. 3 in principle.

A ventilation hole 104 is formed in the head support 100, and the structure is such that a pressurized air flow is supplied to the ventilation hole 104. The airflow that has passed through the ventilation hole 104 is blown out from the air outlet 105 and then the control board 30
sprayed on. This air flow plays a role in stabilizing the generation of ions for the ion generator 20, and serves as an ion passage hole 2 for toner to the control board 30.
It also plays the role of clearing the blockage of the 9.

Further, as shown in FIG. 27, the head support 1
00 is formed with an air flow inlet 107 for introducing air, and the compressed air flow from the compressor is guided through a tube 108 and is configured to flow into the ventilation hole 104.

[0148] The head support 100 has a thickness of 50 μm to 500 μm.
A step 109 of μm is dug, and the distance between the ion generator 20 and the control board 30 is determined by this step 109.

FIG. 28 is a perspective view showing the structure of the main parts of the ion flow recording head 3 shown in FIGS. 26 and 27. Figure 28
As shown in FIG. 2, an ion generator 20, a control board 30, two spacer members 28, and two flexible prints are used to supply control signals for controlling each dot on the control board 30 from a control circuit (not shown).・Cable 5
0 are provided, all of which are mounted on the head holder 100. Since this figure is a view seen from the recording drum 1 side, the second control electrode 33 side of the control board 30 is visible.

The first control electrode 32 is made of a metal layer uniformly formed on one surface of the insulating substrate 31 of the control board 30, and four ion passage holes 29 are formed diagonally on this as shown in the figure. They are arranged separately. Since the electrostatic recording device of this embodiment is capable of recording 1000 pixels in total,
250 sets of four ion passage holes 29 are formed. In addition, the recording resolution is 10 dpm for both main scanning and sub-scanning (
The ion flow recording heads 3 were manufactured for the case of 20 dpm (dots/mm) and the case of 20 dpm, and the ion passage holes 29 are arranged in this manner in order to maintain these resolutions. This will be explained in detail later.

In addition, alignment patterns 51 are formed at the ends of the control board 30 on extension lines of each ion passage hole 29, and holes 5 for adhesive penetration are formed in places on the control board 30.
2 are provided, a control board 30 and an ion generator 20
are integrated by being bonded with adhesive. On the ion generator 20, a first metal layer terminal 53 connected to the induction electrode 22 and a second metal layer terminal 54 connected to the ion generation electrode 24 and the shielding electrode 25 are provided.
can be seen.

Next, each element constituting the ion flow recording head 3 will be explained in detail. First, the ion generator 20 will be explained using FIG. 29. FIG. 29 is an overall view of the ion generator 20. On the insulating substrate 21 made of a ceramic substrate, a first metal layer 55 connected to the induction electrode 22 of FIG. An insulator layer 23 is formed, and an ion generating electrode 24 and a shielding electrode 2 are further formed thereon.
A second metal layer 56 connected to 5 is formed. Further, a bias voltage (Vb+37
, Vb-36) are formed, and the second metal layer 56 is formed with an electrode terminal 54 for applying an AC voltage 39. Such an ion generator 20 can be made entirely by thick film printing technology.

Note that a large number of ventilation holes 57 are formed in the insulating substrate 21 by laser machining or the like. In this embodiment, there are two ventilation holes 57 with a diameter of 1 mm and a pitch of 2 mm.
rows are formed on both sides of the ion generating section. Insulator layer 2
3 is also provided with a ventilation hole 57'. The ventilation hole 57 is provided with the back side of the ion generator 20 (
Hot air is supplied from the insulating substrate 21 side), thereby stabilizing the operation of the ion generator 20.

Regarding the ion generator 20, FIGS. 30 to 3
This will be explained in more detail with reference to 3. 30(a) is a plan view of the ion generator 20, FIG. 30(b) is a back view, and FIGS. 31(a) and 31(b) are sectional views taken along line AA' in FIG. 29. As shown in FIG. 31(a), the insulating substrate 21
An inductive electrode 22 is formed thereon, followed by an insulating layer 23 and finally an ion generating electrode 24 and a shielding electrode 25. Then, as shown in FIG. 30(a), the ion generator 20 is constructed by selectively forming an insulating layer 115 with a thickness of several μm. This insulator layer 115 is for preventing ion generation from unnecessary portions of the electrode.

As shown in FIG. 30(a), the terminal 116 for applying a DC bias voltage to the ion generating electrode 24 (shielding electrode), the induction electrode 22 and the ion generating electrode 2
4 and the shield electrode 25, a terminal 117 for applying an alternating current voltage of about 3 kVP-P is formed, and these voltages are supplied through a high voltage connector 118. It is necessary to provide a sufficient distance between the terminal electrodes so that the electric field between these electrodes becomes larger than the discharge starting electric field of the air and no discharge occurs.

Note that, as shown in FIG. 30(b), the ion generator 20 has a heating resistor 11 on the back side of the insulating substrate 21 (the side on which the ion generating electrode etc. are not formed).
9 is formed. Then, by applying a DC voltage between the two terminals 120 and 120' formed on both sides of the heating resistor 119, a current flows through the heating resistor 119 to generate heat, thereby heating the ion generator 20. are doing. By heating the ion generator 20, nitrogen oxides and the like generated by the discharge are thermally decomposed, and the effect of air blowing is also added, making it possible to extend the life of the ion generator.

The difference between FIGS. 31(a) and 31(b) from FIG. 3 is that there are four locations where ions are generated in the AA' direction. This is because, as shown in FIG. 28, in the ion flow recording head 3 of this embodiment, ion passing holes 29 are formed in the control electrode for each four dots in the sub-scanning direction, and the ion flow recording head 3 of this embodiment is The basic pattern of the generator is 4
It is repeated twice.

The pitch of the ion generating sections in FIG. 31(a) in the sub-scanning direction is equal to the pitch of the ion passing holes 29 of the control electrodes 32 and 33 in the sub-scanning direction. Since the ion passing holes 29 are arranged diagonally at an angle of θ=tan-14, the pitch of the ion generating section is such that the resolution of this embodiment is 10 dp.
400μm for m, 200μm for 20dpm
It is μm. Further, in the case of this embodiment, the width of the shielding electrode 25 was approximately 40 μm, and the space between the shielding electrode 25 and the ion generating electrode 24 was also approximately 40 μm. Incidentally, air blowing holes 57 and 57' are formed in the insulating substrate 21 and the insulating layer 23, so that hot air is flowed from the substrate 21 side.

FIG. 31(b) is a cross-sectional view taken along the line A-A' showing another example of the ion generator 20, in which the induction electrode 22, which was divided into four in FIG. 30(a), is combined into one. There is. By doing this, the manufacturing accuracy of the induction electrode 22 is rough and good, and the induction electrode 22 which is the first metal layer 55, the ion generating electrode 24 and the shielding electrode 2 which are the second metal layer 56,
It has the advantage that the alignment accuracy with 5 can also be made rough. However, since the capacitance between these electrodes also increases, an AC voltage with a large current capacity is required. As shown in FIGS. 26 and 27, the ion generator 20 having the configuration described above is mounted on a head support 100.
It is inserted into a 500 μm groove 121 formed in .

FIGS. 32 and 33 are enlarged views of portions B and C of the ion generator 20 shown in FIG. 29, respectively. 32 and 33, the two-dot chain line indicates the insulating substrate 21, the broken line indicates the induction electrode 22, which is the first metal layer 55, the one-dot chain line indicates the insulator layer 23, and the solid line indicates the ion generation, which is the second metal layer 56. The patterns of the electrode 24 and the shielding electrode 25 are shown respectively. On the insulating substrate 21 in which the ventilation hole 57 was formed,
First, the induction electrode 22, which is the first metal layer 55, is formed. In these figures, in order to simplify the explanation, the induction electrode 2
2 is shown in FIG. 31(b), which is not divided into four parts. Next, an insulator layer 23 having ventilation holes 57' is formed thereon. The air blowing holes 57' of the insulating layer 23 are slightly larger than the air blowing holes 57 of the insulating substrate 21, so that even if the positional accuracy of the pattern changes slightly, the hot air can pass through. It has become. By blowing warm air (above room temperature to around 100℃),
The amount of ions generated can be stabilized. Furthermore, a second metal layer 56 is formed on this insulator layer 23 by thick film printing technology. Finally, a pattern of the ion generating electrode 24 and the shielding electrode 25 is formed by etching, and the ion generator 20 is completed.

Note that four notches 58 are formed in the second metal layer 56 in FIG. 32, and four bar patterns 59 are formed in the second metal layer 56 in FIG. 33. These notches 58 and bar patterns 59 are patterns for alignment with the control electrodes 32 and 33 placed thereon. In this embodiment, the positioning notch pattern 58 has a width of about 40 μm and a pitch of 400 μm (20 μm).
In the case of 20 dpm, the width of the bar pattern 59 is approximately 40 μm, and the pitch is 400 μm (200 μm in the case of 20 dpm).

In other words, these alignment patterns 58
, 59 and the ion passage hole 29 on the control board 30, which ion passage hole 29 is aligned.
It becomes possible to stably extract a certain amount of ions from In the case of this embodiment, these alignment patterns 5
8 and 59 are formed on the extension line of the shield electrode 25. Therefore, in the aligned state, the ion passage hole 29 is located directly above the shielding electrode 25, as shown in FIG.

On the other hand, the control board 30 is connected to the head support 100.
It is pasted along. A first control electrode 32 and a second control electrode 33 are formed on the control board 30 from the side closest to the ion generator 20 . At least one of the first and second control electrodes 32 and 33 is configured such that a control voltage can be independently applied to each ion passage hole 29. In this embodiment, the first control electrode 32
are individual control electrodes, and the second control electrode 33 is a solid electrode so that a uniform voltage is applied thereto.

[0164] In this embodiment, the first control electrode 32 is an individual electrode. In other words, the control electrode 32 inside the control board 30 near the ion generator 20 is an individual electrode. For this purpose, a through hole is formed at the end of the control board 30 to take out the first control electrode 32 to the front side. The control board 30 is adhered to the head support 100 in an aligned state and is integrated with the head support 100. Ideally, it is desirable to align the positions of the four individual ion generators so that they match the positions of the ion passage holes 29 of the control electrode 32, but great precision is not required.

As shown in FIGS. 26 and 27, a large number of IC drive circuits (hereinafter referred to as driver ICs) 124 are mounted on the drive circuit board 103. As these driver ICs 124, ICs conventionally used in thermal heads can also be used. In conventional thermal head drivers, each heating resistor has a
Although the structure is such that a current of 0 mA flows, in the printer of this embodiment, it is necessary to flow only a current of about several μA per one control electrode. Therefore, when manufacturing a new driver IC 124, it is necessary to use a highly integrated driver IC that drives 128 bits, since the withstand voltage is almost the same as the conventional one, but the current capacity is much smaller, and the chip area is also smaller. It also becomes possible to manufacture.

FIG. 34 shows an internal block diagram of the driver IC 124 used in the printer of this embodiment. Image data is input from the Sin terminal 125 and transferred within the shift register 126 in response to a clock signal (CLOCK) 127. This shift register 126 has, for example, a 64-bit configuration, which allows the driver IC 124 to turn on/off 64 pixels. The data transferred to the shift register 126 is transferred to the 64-bit latch 12 by the latch signal (LATCH) 128.
9 and retained. Enable signal (EN)
130 is applied, the gate 131 is opened only when mark data is held in the latch 129, the driver transistor 132 is turned on, and only this pixel is recorded. In addition, each driver IC
124 is the output of the 64-bit shift register 126.
It is output to the ut terminal 133. Sout terminal 13
3 is connected to the Sin terminal 125 of the driver IC 124 at the next stage, so that it is possible to correspond to a large number of pixels. Each signal passes through wiring formed on the drive circuit board 103 and is supplied from an external control circuit (not shown) via a connector 139.

[0167] A4 width (210
For example, in the case of a line head for 4,200 dots (mm), there are 4,200 dots of ion passage holes 29 in one line. The first control electrodes 32 that independently drive these ion passage holes 29 are drawn out in alternate opposite directions, as shown in FIG. Therefore, the drive circuit board 1 on one side
03 will have 33 driver ICs 124 mounted on it.

[0168] Furthermore, as shown in FIGS. 26 and 27,
Two drive circuit boards 1 equipped with driver ICs 124
03 is fixed onto the head support 100 with an adhesive or the like. After the drive circuit board 103 is fixed on the head support 100, the first control electrode 32 and the control signal line on the drive circuit board 103 are connected by wire bonding 136, and further molded with resin 138. Insulating. Also, put the metal cover 138 over it, and screw the screws 13
It is fixed at 5. This is because the high voltage AC voltage such as the ion generator 20 is located close to the driver IC.
This prevents the 5V logic circuit from malfunctioning due to high frequency noise. Therefore, metal cover 138 is preferably connected to ground potential. Note that FIG. 27 shows a state with the metal cover 138 removed.

The ion flow recording head 3 assembled in this way is attached to the head mounting rail 14 attached to the printer main body as shown in FIGS. 26 and 27.
0 in the groove 141 formed in the head, slide it in the direction of the rail, and set it at the original recording position. In addition, when removing the ion flow recording head 3, it is possible to remove only the ion flow recording head 3 by removing each connector and sliding it on the head mounting rail 140.

Furthermore, the ion flow recording head 3 of the present invention has a structure that allows only the ion generator 20 to be replaced. That is, as shown in FIG. 27, a positioning hole 143 for fixing the position of the ion generator 20 is formed in the side plate 142 of the head support 100. Therefore, in the case of FIG. 27, the ion generator 20 can be set in the ion flow recording head 3 by pushing it from the right side to the left side in the figure. Moreover, by pulling out the ion generator 20 from the left side to the right side in the figure, it is possible to remove it from the ion flow recording head 3. Because of this, even if the ion generator 20 deteriorates, the entire ion flow recording head 3 (control board 30
, drive circuit board 103, etc.), and only the ion generator 20 needs to be replaced, so it is also possible to reduce the cost required for maintenance of the device.

Next, regarding the control board 30, FIGS.
This will be explained using 8. 35(a) and 35(b) are plan views of the control board 30 viewed from the front side, that is, from the recording drum 1 side in FIG. 3, and the second control electrodes 33 are visible.

In the example of FIG. 35(a), the second control electrode 33
is a so-called solid electrode formed on the entire surface of the substrate, and is connected to the ground potential as shown in FIG. The control board 30 has a hole 51 for alignment, and the control board 3
A hole 52 for pouring an adhesive for bonding the ion generator 20 and the ion generator 20 is formed.

In the example of FIG. 35(b), the ion passage hole 29
A second control electrode 33 is formed only around the periphery. By patterning the solid electrode by etching, the second control electrode 33 having such a pattern can be formed. By reducing the area of the second control electrode 33 in this way, the capacitance formed between the first control electrode 32 and the second control electrode 33 becomes smaller, so the drive circuit and drive power supply Current capacity can be reduced. Note that both ends of the second control electrode 33 extend to the end of the control board 30 so that terminals can be taken out on both sides (in the sub-scanning direction). Second
The portions 33a and 33b separated from the control electrode 33 by patterning when forming the control electrode 33 are essentially unnecessary for operation, but in this embodiment, they are left electrically floating as they are to provide strength. It is left in its original condition and used. The second control electrode 33 and these separated parts 3
By electrically connecting 3a and 33b at one point, Figure 3
It is also possible to have almost the same function as 6(a).

FIG. 36 is a plan view of the control board 30 when viewed from the back side (first control electrode 32 side), and similarly to when viewed from the second control electrode 33 side, the ion passage hole 29, position A hole 51 for alignment and a hole 52 for pouring adhesive are visible. The second control electrode 33 was designed so that a common potential was applied to each ion passing hole 29, whereas the first control electrode 32 was finely patterned as shown in the figure, and each ion passing hole 29 The difference is that each pixel is formed independently so that different potentials can be applied temporally independently.

[0175] Each tip of the first control electrode 32 is connected to a flexible cable connection terminal 60 at the end of the control board 30, and a control voltage is applied here from the flexible cable. Note that in FIG. 36, the recording resolution is 10
dpm is shown, and in this case, lead wires are drawn out vertically for every two control electrodes 32, so the pitch between the wires is 200 μm (5 wires/mm). In addition, the hole 52 for pouring the adhesive has a diameter of 100 μm.
5 holes are formed in each sub-scanning direction at a pitch of 400 μm, and these holes 5 for pouring adhesive are formed in 10 wirings.
Two groups are arranged. Therefore, the wiring of the control electrode 32 has a width of 100 μm and a pitch of 200 μm near the ion passage hole 29 and the flexible cable connection terminal 60.
In contrast, the width is 92 μm and the pitch is 184 μm near the hole 52 for pouring the adhesive. Note that the wiring width of the second control electrode 32 in the very vicinity of the ion passage hole 29 is 66 μm, which will be explained with reference to FIG. 37. The length of each flexible cable connection terminal 60 is changed for each flexible cable connection terminal 60 in order to simplify positioning when connecting to a flexible cable.

[0176] When the lead wires are drawn out to both sides in the sub-scanning direction in this way, in the case of a resolution of 10 dpm, the resolution (wiring density) of the lead wires is 5 wires/mm near the ion passage hole 29, and the flexible cable Even in the vicinity of the connection terminal 60, it is 5 pieces/mm. On the other hand, in the case of a resolution of 20 dpm, if two lead wires are drawn out on both sides in the sub-scanning direction, the wire density near the ion passage hole 29 is 10 wires/mm. However,
Flexible cables have a high wiring density of about 8 cables/mm, and as wiring density increases, it becomes difficult to connect the flexible cable connecting terminal 60 to the flexible cable.
In the vicinity of the cable connection terminal 60, the wiring density of the lead wiring is 8 wires/mm. Therefore, the extraction wiring is not a simple parallel wiring as shown in FIG. 36, and the wiring density is 10 lines/mm near the ion passage hole 29.
8 wires near flexible cable connection terminal 60/
The wiring is such that it extends to mm.

FIG. 37 shows the ion passage hole 2 of the control board 30.
9 is an enlarged view of the vicinity. The ion passage holes 29 have four holes arranged diagonally, and all dots are formed by repeating this process. In this embodiment, the angle θ between the main scanning direction and the direction in which the holes are lined up is set to satisfy θ=tan-1 (±4). That is, as shown in the figure, there is a gap between the pitch P of the ion passing holes 29 in the main scanning direction and the pitch l of the ion passing holes 29 in the sub scanning direction.
The relationship l/P=4 holds true.

The reason for arranging the ion passage holes 29 in this manner is as follows. The diameter of the ion passage hole 29 is 50μ
Consider the case where the recording resolution is 20 dpm. In such a case, if the ion passage holes 29 are arranged in a line in the main scanning direction, adjacent ion passage holes 29 will be continuous, making it impossible to form the first control electrode 32. Therefore, it becomes necessary to arrange the ion passage holes 29 diagonally. however,
Even when the ion passage holes 29 are arranged diagonally, each passage hole must be placed at a position that is an integral multiple of the resolution in the sub-scanning direction. In the case of this example, since the recording resolution is equal to 20 dpm for both main scanning and sub-scanning, θ=tan-
It is necessary to arrange the ion passage holes 29 at an angle θ of 1N (N is an integer).

First, N=1, that is, θ=tan-11=4
Consider the case of 5°. In this case, the distance between the centers of adjacent ion passing holes 29 is 71 μm, so the closest part is 2
It becomes 1 μm. It is necessary to form the first control electrode 32 around such an ion passage hole 29. Currently, the line width and space that can be stably patterned by etching and the like are both limited to about 30 μm. Therefore, a distance of at least 90 μm is required between adjacent ion passage holes 29, and N=1 is inappropriate. For the same reason, N=2 is also inappropriate. If N=3 or more, this condition can be cleared. However, since signals are delayed in electrical circuits, the circuit becomes simpler when N is an even number. Therefore, it is preferable that N=4 or more, which is an even number.

Therefore, in the case of N=4, the ion passage hole 29
Next, consider how many rows should be arranged in the sub-scanning direction. First, in the case of two rows, the closest distance between the ion passage holes 29 in each row is 50 μm, which is inappropriate for the reasons mentioned above. Now, let us consider how to draw out the wiring from the first control electrode 32. Now, if all the lead wiring is pulled out in one direction in the sub-scanning direction, and if the etching limit is 30 μm for both line width and space, then if there are M columns, the width of (60 x M + 30) μm is the width of the adjacent line of each column. It is necessary between the matching ion passage holes 29. On the other hand, the distance between adjacent ion passage holes 29 in each row is (50×M−5
0) μm. In other words, when M≧1, always (60×M
+30)>(50×M-50), and therefore it is impossible to draw out the wiring in one direction. Therefore, the lead wiring must be distributed to both sides in the sub-scanning direction. Considering this, with 3 rows, it becomes complicated to draw out the wiring and rearrange the signals, so
It is desirable to adopt four rows. For the above reasons, Figure 3
The arrangement of the ion passage holes 29 and the method of leading out the first control electrode 32 as shown in FIG. 7 were determined.

Further, as shown in FIG. 37, a positioning pattern 51 is formed on the extension line of each row of ion passing holes 29. In the case of this embodiment, holes are provided as the alignment pattern 51. Figure 38
Three positioning holes 51 are opened in each row near the end surface of the control board 30 as shown in FIG. Then, the end face 61 of the control board 30 is formed by cutting aiming at the center hole. The end surface 61 of the control board 30 formed by this cutting is
It is not necessarily necessary to cut along a line passing through the center of the hole in the middle of the alignment pattern 51. For example, even if there is only one alignment pattern 51 on the control board 30 and the end surface 61' is formed so that the hole is only partially formed,
Furthermore, even if the end surface 61'' is formed so that there are three alignment patterns 51 on the control board 30, the positioning function is not lost.In this way, the position of the end surface 61 of the control board 30 is In order not to lose its function even if there is a slight deviation, the end surface 61 of the control board 30 is formed by drilling three holes as a positioning pattern and cutting at the center of the middle hole.

Next, a method for manufacturing the control board 30 will be described with reference to FIGS. 38(a) to 38(e). First, Figure 38
As shown in (a), a copper foil 70 with a thickness of about 18 μm and a copper foil 70 with a thickness of about 25 μm
Two single-sided copper-clad substrates 72 each made of a .mu.m thick polyimide resin layer 71 are prepared, and both are bonded together with an adhesive 73 (about 15 .mu.m thick) so that the surface of the copper foil 70 is on the outside. Next, as shown in FIG. 38(b), only the copper foil 70 on one side is etched to form the first control electrode 32. next,
As shown in FIG. 38(c), the polyimide resin layer 71, the adhesive layer 73, and the polyimide resin layer 71 are sequentially etched to open the ion passage holes 29. Next, the ion passage hole 29 is completed by etching the second layer of copper foil 70, but in order to prevent the first control electrode 32 of the first layer from being etched at the same time, first Figure 38(d)
As shown in FIG. 3, a gold plating layer 74 is applied to the already formed first control electrode 32. By etching the copper foil 70 in this manner, the control board 30 having the ion passage holes 29 as shown in FIG. 38(e) is completed.

In FIG. 38, two single-sided copper-clad boards are used,
An example was shown in which a double-sided copper-clad board was created by adhesion, and the ion passage hole 29 was opened by etching to create the control board 30. However, even if a double-sided copper-clad board in which copper foil is pasted on both sides of the resin layer is used, the control board 30 can be
It is possible to create Further, in the case of a double-sided copper-clad board, the copper foil 70 on both sides may be etched first, and then the resin portion may be etched from both sides.

[0184] The ion generator 20 and the control board 30 are manufactured by the method described above. Finally, by integrating these ion generator 20, control board 30, spacer member 28 and flexible cable 50,
The ion flow recording head 3 as shown in FIG. 28 is completed.

FIGS. 39 and 40 show the ion generator 20
FIG. 3 is a plan view showing a state in which the ion generator 20 and the control board 30 are aligned by placing a spacer member 28 thereon and further placing a control board 30 thereon. Control board 30
The upper alignment hole 51 matches the alignment cutout pattern 58 and bar pattern 59 formed on the ion generator 20 as shown in the figure. In this state, the ion generator 20 and the control board 30 can be integrated by injecting an adhesive through an adhesive injection hole made in the control board 30 and bonding them together. Note that the control board 30 and the flexible cable 50 were connected by pressure welding.

FIG. 41 shows a sectional view taken along line DD' in FIG. 28. Control board 30 and flexible cable 50
The respective electrodes of the rubber 75 are aligned with each other.
It is held down by a holding plate 76 and fastened to a head holder 78 by screws 77 in order to press the electrodes into contact with each other. In this way, the connection between the control board 30 and the flexible cable 50 is realized.

Next, another embodiment of the present invention will be described. FIG. 42 is a cross-sectional view of an ion flow recording head 3 according to a second embodiment of the present invention. In the first embodiment, the second control electrode 33 is at ground potential, but in the second embodiment, the first control electrode 32 is at ground potential.

FIG. 42 shows a state in which recording is actually performed, and the second control electrode 33 is connected to the first control electrode 33.
2, so that a negative control voltage Vc34 is applied to
An electrical switching circuit 35 is controlled. By doing this, an electric field E2 similar to that shown in FIG. 3 is formed between the first control electrode 32 and the second control electrode 33, so that the electric field E2 is generated from the slit 26 which is the ion generating part. The positive ions can pass through the ion passage hole 29. Therefore, an electrostatic latent image can be formed on the insulating layer 42 of the recording drum 1, which is uniformly charged with negative ions.

In this example, an electric field E similar to that shown in FIG.
This embodiment differs greatly from the first embodiment in that the control voltage Vc34 is a negative voltage in order to form the second embodiment. When no pixel is formed, the contact of the switching circuit 35 is connected to the b side, the first control electrode 32 and the second control electrode 33 are at the same potential (earth potential), and these electrodes 32, 33 The electric field E2 generated between the two becomes zero. Therefore, ions cannot pass through the ion passage hole 29, and no pixel is formed.

43 and 44 are a perspective view and a sectional view taken along the line EE' of the ion flow recording head 3 actually constructed based on the idea shown in FIG. 42. As shown in FIG. 43, in this embodiment, the second control electrodes 33 are individual electrodes, so the second control electrodes 33 are formed in large numbers, which is a big difference from FIG. 28. Other points are almost the same as FIG. 28. In the case of this embodiment, the second control electrode 33 and the flexible cable 50 may of course be connected by pressure welding as shown in FIG. 41, but here, as shown in FIG. Connected by bonding.

That is, the ion generator 20 and the control board 30 are first attached to the spacer member 2 in the same manner as in the first embodiment.
8 and glue them together, and attach them to the head holder 7.
8 by gluing or screwing. Next, the electrode position on the flexible cable 50 and the second control electrode 3
With position 3 aligned, connect flexible cable 5
0 on the head holder 78 in the same way. Finally, the electrode on the flexible cable 50 and the second control electrode 33 are connected (wire bonding) with a gold wire 79 using a wire bonder to complete the ion flow recording head 3. Note that, in reality, if the gold wire 79 is left bare, there is a problem in terms of insulation and strength, so as shown in FIG. 44, it is covered with a resin molded part 80 (not shown in FIG. 43). .

FIGS. 45 and 46 are a perspective view and a sectional view taken along line FF' of the ion flow recording head 3 according to the third embodiment. This example is similar to the second example,
The first control electrode 32 is set to a common ground potential, and the second control electrode 33 is configured to control individual picture points. Further, in this embodiment, a driver IC 81 for controlling the second control electrode 33 is mounted on the ion flow recording head 3. Since the driver IC 81 is mounted on the ion flow recording head 3 in this manner, it is possible to downsize the apparatus. Furthermore, since the signal lines do not need to be routed over long distances using flexible cables, crosstalk due to capacitance between the signal lines can be reduced, and the current capacity of the drive circuit can also be reduced.

[0193] This ion flow recording head 3 is manufactured as follows. That is, as shown in FIG. 46, first, the insulating substrate 21 of the ion generator 20 and the control substrate 30 are bonded and integrated with the spacer member 28 in between, using the same method as in the first embodiment, and then these are attached to the head. It is fixed on the holder 78 by adhesive or screwing. Next, driver IC81
With the electrode position on the driver board 82 on which is mounted aligned with the position of the second control electrode 33, the driver board 82
is similarly fixed on the head holder 78. Finally, the electrode on the driver substrate 82 and the second control electrode 33 are wire-bonded with the gold wire 79 using a wire bonder, thereby completing the ion flow recording head 3. Then, using a wire bonder, the electrode on the flexible cable 50 and the second control electrode 33 are connected with a gold wire 79 (wire bonding). In this case as well, the gold wire 79 is covered with a resin mold part 80 (omitted in FIG. 43). Finally, a metal cover 83 is hung to cover the driver IC 81 and the resin molded part 80, and is further fixed to the head holder 78 with screws 84 or the like.

[0194] In this way, the metal cover 83
The reason for covering C81 is not only to prevent the driver IC 81 and driver board 82 from getting dirty with dust or floating toner, but also to prevent the driver IC 81 from becoming dirty with dust or floating toner, but also because the 5V operation logic circuit section of the driver IC 81 is connected to the high voltage AC that is applied to the ion generator 20. This is also to prevent malfunctions caused by the power supply. Therefore, it is more desirable that the metal cover 83 be connected to the ground potential. In addition, in order to hang the metal cover 83, please refer to Fig. 45.
It is necessary to apply an insulating layer to the area shown by the dashed line as shown in the figure.

[0195] The driver IC 81 has a number of 10 as in this embodiment.
If the head can be driven at a low voltage of V, a thermal head driver IC that has been commercially available can be used. Furthermore, even when performing high-speed recording of 50 sheets/min or more, conventionally available drive voltages of 100 to 20
It is possible to use a 0V EL driver IC or the like. In these driver ICs, 64-bit drive is common, and when there are 1000 dots of ion passage holes 29 in total as in this embodiment, one driver board 82 is used.
It is sufficient if eight driver ICs 81 are mounted on the top. A terminal 85 is formed on the driver board 82 to which a power supply and GND for driving the driver IC 81, a 5V power supply and GND for logic, data, a data transfer clock, a latch signal, a recording signal, etc. are supplied.

FIGS. 47 to 49 show other shapes of the ion passage hole 29 and the control electrode 32 around it. In FIG. 37, the ion passage hole 29 has a circular shape, but in FIG. 47, it has an elliptical shape with a short dimension in the sub-scanning direction. The reason for this is as follows. In the electrostatic recording method using an ion flow recording head like the present invention, in principle, 50 A4 sheets/
High-speed recording of more than 1 minute is possible. During recording, the recording drum 1 is constantly moving at a constant speed. The density of each pixel can be controlled by controlling the driving voltage or the pulse width of the driving pulse. However, it is generally easier to control the pulse width, and in particular, conventional commercially available driver ICs for thermal heads are usually configured such that individual image points can only be controlled by the pulse width.

However, when the pulse width is controlled, since the recording drum 1 is moving at a constant speed, the ion passing holes 2
A relative movement will occur between the recording drum 9 and the recording drum 1. That is, when the ion passage hole 29 is circular as shown in FIG. 37, a circular ion flow moves on the recording drum 1 in the sub-scanning direction. Therefore, the recorded pixel has a shape extending in the sub-scanning direction, and furthermore, the resolution in the sub-scanning direction is degraded from a specified value. Therefore, by providing an elliptical ion passage hole 29 with a shorter sub-scanning direction as shown in FIG. 47, for example, the above-mentioned problem can be solved.

FIG. 48 shows another example of an elliptical ion passage hole 29, which differs from the examples in FIGS. 37 and 47 in that adjacent ion passage holes 29 are partially overlapped in the main scanning direction. It is different from Even if the ion passing holes 29 partially overlap each other in this way, the ion beam is focused by the lens effect of the electric field, so the resolution in the main scanning direction will not deteriorate. The lens effect of the electric field is best exhibited when the electric field shown in FIG. 3 satisfies E3>E2>E1. The ion passage hole 29 is formed by etching, as explained in FIG. Therefore, basically any pattern of ion passage holes can be formed, but when the resolution is high, the larger the pattern, the easier it is to form. Figure 48
Since the ion passage hole 29 can be formed larger than the ion passage hole 29 in FIG. 47, it is easier to form it.

FIG. 49 shows an example of ion passage holes 29 that are rectangular and partially overlap in the main scanning direction. Ideally, when trying to control the density by pulse width control, the resolution in the main scanning direction is a specified value, and a linear ion beam with almost no width in the sub-scanning direction is sent over the recording drum in the sub-scanning direction. This is a form in which the length of a recording pixel in the sub-scanning direction is controlled by controlling the pulse width while scanning. For this purpose, a rectangular ion passage hole 29 as shown in FIG. 49 may be used to focus and record the ion beam by the lens effect of the electric field. Note that the reason why the corners of the rectangle of the ion passage hole 29 are rounded as shown in FIG. 49 is because when actually etching the ion passage hole 29, the etching time must be longer in order to form the ion passage hole 29 sufficiently deep. This is because there is.

Here, in FIG. 37, θ=tan-18
Consider the case where In this case, the ion passage holes 29 that are adjacent to each other in the main scanning direction overlap each other by half. However, it is also possible to double the resolution in the main scanning direction to 40 dpm by focusing the ion beam and recording using the lens effect of the electric field.

[0201] Also, the magnitude of the electric field can be set to, for example, E3<E2<
By setting it to E1, etc., it is also possible to utilize the lens effect of the opposite electric field. That is, in a case where adjacent pixel points are in contact with each other in the main scanning direction as shown in FIG. 47, gaps may occur between the pixel points. In such a case, by recording a pixel larger than the ion passage hole 29 due to the lens effect of the opposite electric field, it is possible to realize good recording without gaps between the pixel points.

FIG. 50 shows another example of the method for manufacturing the control board 30. In this example, first, a double-sided copper-clad substrate is used, as shown in FIG. 50(a), in which copper foil 90 with a thickness of about 18 μm is bonded to both sides of a glass polyimide substrate 91 with a thickness of about 100 μm. As shown in FIG. 50(b), the copper foil 90 of this substrate is first etched to form portions 90' that will become individual control electrodes. Next, using a drill having a diameter of 100 μm, ion passage holes 29 are formed by machining from the opposite side of the individual electrodes, as shown in FIG. 50(c). At this time, a burr 92 of about 25 to 30 μm is formed on the glass/polyimide substrate 91 on the exit side of the drill. Finally, by electroless plating the copper on both sides with gold 93, the control board 30 is completed as shown in FIG. 50(d).

In this case, it is desirable that the side with the burr 92 be the second control electrode 33 and the opposite side be the first control electrode 32. This is because by doing so, the ion flow can be controlled at a lower voltage. Therefore, the control board 30 shown in FIG. 50(d) is used in the ion flow recording head with the first control electrode 32 at ground potential, which is used in the electrostatic recording device of the second embodiment shown in FIG. Can be used for 3. In addition, Figure 3
When used in the example shown in FIG. 50(c), in the process of forming the ion passage holes 29 using a drill, drilling is performed from the etched pattern side, and burrs are formed on the common pattern side. can.

[0204] When forming the ion passage hole 29 by drilling in a double-sided copper-clad glass polyimide substrate,
The limit is to form a hole of about 100 μm, and 10 d
There are problems such as it is difficult to achieve a resolution higher than pm, it takes time to drill a large number of holes one by one with a drill, and the drill wears out rapidly. Another drawback is that the shape of the ion passage holes 29 cannot be arbitrarily selected. However, for the resolution problem, Figure 4
As shown in 7 to 49, the problem can be solved by allowing the image points to overlap in the main scanning direction and narrowing down the ion beam using the lens effect of the electric field. In addition, a large number of ion passage holes 29
The problem of having to form it with one drill can be solved by using it in a serial printer with at most 100 dots, rather than in a line printer with 1000 dots as in this embodiment. Ru.

When the method of FIG. 50 is compared with the method of laminating two single-sided copper-clad polyimide resin sheets described in FIG. 38, it has the following advantages. One is that since no adhesive is used on the substrate, there are no problems with variations in thickness, etc. When using single-sided copper-clad polyimide resin,
Since the two sheets are pasted together using adhesive, it is difficult to control the thickness of the adhesive. Additionally, glass/polyimide substrates are hard, so they have the advantage of being easy to handle. In particular, in the process of forming fine patterns by etching,
When a copper-clad polyimide resin is used, the substrate itself tends to be distorted, but when a glass polyimide substrate is used, there is no such problem.

In the example shown in FIG. 38, only one side of the control board 30 is plated with gold, but in the example shown in FIG. 50, both sides are plated with gold. Ideally, both sides should be gold plated.
Will not be corroded by oxidation or ion irradiation,
Although there is no problem in terms of stability, it is necessary to plate at least the first control electrode 32 located on the ion generator 20 side with gold. This is to take advantage of the stability of gold to prevent the electrode from being eroded or electrolytically eroded by various ions generated during ion generation, or by substances generated by the reaction of these ions with moisture.

FIG. 51 shows a control electrode 32 consisting of individual electrodes.
Another example of how to draw out the wiring is shown below. As explained in FIG. 37, it is virtually impossible to draw out the wiring of the individual control electrodes in only one direction when the resolution is as high as 20 dpm. Therefore, in FIG. 51, as in FIG. 37, the lead wires of the control electrodes 32 are drawn out on both sides. However, in the case of FIG. 37, each control electrode 32 is distributed to both sides, whereas in FIG. 51, each individual control electrode 32 is alternately distributed. In the example shown in FIG. 51, although the routing of the lead wires is a little complicated, it has the advantage that the arrangement control of image data is simple in terms of electrical circuitry. Note that even in the case where the ion passage holes 29 are elliptical or rectangular as shown in FIGS. 47 to 49, it is possible to alternately distribute the wiring of the control electrodes 32 as shown in FIG. 51.

FIGS. 52 and 53 each show a modification of the first embodiment shown in FIG. 3. In the embodiment of FIG. 3, the second control electrode 33 is at ground potential when recording a pixel, and the first control electrode 32 is connected to contact a by a switching circuit 35, and the control voltage Vc34
is applied. Furthermore, when no pixel is recorded, the second control electrode 33 is at ground potential, but the first control electrode 3
2 is also connected to contact b by the switching circuit 35, so that the ground potential is applied to it. Therefore,
Since the electric field E2 formed between the first control electrode 32 and the second control electrode 33 becomes 0, the generated ions cannot pass through the ion passage hole 29.

However, in reality, a slight electric field is formed from the first control electrode 32 to the second control electrode 33, ions are accelerated by the electric field E1, or some of the generated ions are Because some ions have a large initial velocity, ions pass through the ion passage hole 29, albeit in a small amount. As a result, when the recording speed becomes low, for example, about 20 sheets/min, background fogging occurs due to the leaked ions.

[0210] Therefore, if no pixel is recorded, as shown in Fig. 5
By forming an electric field E2' directed from the second control electrode 33 to the first control electrode 32 as shown in FIG. 2, such leakage of ions can be almost eliminated. For this reason, in FIG. 52, a reverse bias Vc-95 is applied between the first control electrode 32 and the ground potential. This reverse bias Vc-95 may be about 10 to 20V. The embodiment shown in FIG. 53 has exactly the same concept as the embodiment shown in FIG. 52. That is, the second control electrode 3 is always
Since the positive bias voltage Vc+ 96 is applied to the electrode 3, it is connected to contact b by the switching circuit 35 when no pixel is recorded, and when the ground potential is applied to the first control electrode 32, the second control electrode 32 An electric field E2 is formed from the control electrode 33 toward the first control electrode 32, and leaking ions can be stopped. In the example of FIG. 52, it is necessary to perform + and - switching, but in the example of FIG. 53, only + switching is required, which has the advantage of simplifying the circuit. However, even if the control voltage Vc34 is usually sufficient at 60V, in the case of FIG.
Since a positive bias voltage Vc+96 of about ~20V is applied, a control voltage Vc34 of 70 to 80V is required.

[0211] Even if the reverse electric field E2 is applied between the first and second control electrodes 32 and 33 in this way, ions that are about 1/100 to 1/1000 of the ions used during normal recording are It will leak. To deal with this, the switching circuit 40 is turned off so that the AC voltage 39 is not applied during recording.
The switching circuits 35 and 38 may each be connected to the contact b.

FIG. 54 shows yet another embodiment. In the previous embodiment, the ion generator 20 and the control board 30 were bonded together by injecting an adhesive through an adhesive injection hole drilled in the control board. This method inevitably requires manpower, and it is difficult to efficiently produce the ion flow recording head 3.

[0213] Therefore, a method as shown in FIG. 54 can be considered. This is a method in which, when manufacturing the ion generator 20, an adhesive 57 that becomes sticky when pressure is applied is applied inside the area indicated by the dashed line in the figure. This can be fully handled using the thick film printing technology used in manufacturing. By doing so, when the alignment of the ion generator 20 and the control board 30 is completed, the integration of the two can be completed simply by applying pressure.

[0214] In all of the above embodiments, explanation is limited to the method of first uniformly charging with negative ions, then forming an electrostatic latent image with positive ions, and then performing reversal development to form an image. However, it is not limited to this. Conversely, it also includes a case where the image is uniformly charged with + ions and then an electrostatic latent image is formed with - ions. However, in that case, the positive and negative polarities of all the DC power supplies shown in FIG. 3, for example, must be reversed. Further, in the above description, the ion generator 20 has been described as an AC high-density solid ion generator, but the present invention is not limited to this, and for example, a DC high-density solid ion generator may be used.

Next, another embodiment of the end face type ion flow recording head 3 is shown in FIGS. 55 to 58. The example of FIG. 55 is shown in FIG.
The difference from the sixth embodiment is that the air circulation holes 104 are concave. In the case of the embodiment of FIG. 26, it was difficult to make a wide head because the hole 104 was circular, but in the embodiment of FIGS. 55 to 58, the head support 100 was The concave air circulation holes 104 are formed by carving from the blank, thereby making it possible to easily create a wide head.

[0216] In this ion flow recording head 3, a control board 30 is attached to a head support 100 in which such a concave air circulation hole 104 is formed. A board 103 is further attached to the control board 30 for reinforcement. Therefore, it becomes possible to mount the driver IC 124 on the control board 30 and bond the wiring. Here, the ion generator 20 is formed on a ceramic substrate, but is integrated with the ion generator support 146 for reinforcement and ease of handling. Ion generator support 146
An air blow-off hole 105 is formed in advance in the control electrode, and the air flow supplied from the air circulation hole 104 is blown out from this air blow-off hole 105 toward the control electrode side.

A groove 141 is formed in the head support 100, and a head mounting rail 1 is inserted into this groove 141.
40 are engaged. By sliding the rail 140, the ion flow recording head 3 can be removed from the electrostatic recording apparatus main body. Note that even if the rail 140 is slid, the distance between the drum 1 and the head 3, the angle of the head 3 with respect to the drum 1, etc. may change. Therefore, the plate spring 145 is attached to the head mounting rail 140.
These conditions are prevented from changing by attaching the head support body 100 and pressing the head support body 100 with the leaf spring 145.

The embodiment shown in FIG. 56 is an example in which the ion generator support 146 is not provided with air blow holes 105. In this example, the ion generator support 146 is configured to have a considerably smaller width than the air flow holes 104, so that the head support 100 and the ion generator support 146
A gap 105 is created between the two, and this gap 105 is used as an air blowing hole 105.

FIGS. 55 and 56 each show a cross-sectional view of the ion flow recording head 3. When shown in a side view, there is a side plate 142 similar to that shown in FIG.
An air intake port 107 is formed in the tube 10.
The structure is such that the air flow introduced at 8 is supplied. Further, a positioning hole 143 is formed in the side plate 142, and the ion generator support 146 is configured to engage with this positioning hole 143 to determine the position of the ion generator 20. Therefore, it is also possible to replace the ion generator 120 together with the ion generator support 146.

That is, even if the ion generator support 146 integrated with another ion generator is brought, the side plate 14
The ion generator 20 can be installed in the correct position by simply replacing it in accordance with the positioning hole 143 formed in the ion generator 20. Among the components of the ion flow recording head 3, the ion generator 20 has the shortest lifespan, and compared to this, the control electrodes 32, 33, driver IC 124, etc. have a very long lifespan. However, the driver IC 12 accounts for most of the manufacturing cost of the ion flow recording head 3.
4, etc., and if the ion generator 20 is provided integrally with the head 3, the life of the head 3 will be determined by the life of the ion generator 20. The production cost of the ion generator 20 is relatively low, and if it deteriorates, it is possible to replace only the ion generator 20.

The ion flow recording head 3 of FIGS. 57 and 58 includes the ion generator 2 together with the ion generator support 146.
This is another example of a structure in which 0 can be replaced, and the tip portion of the head 3 is shown. In the examples shown in FIGS. 55 and 56, the ion generator 20 was aligned using the positioning hole 143 formed in the side plate 142, but in the example shown in FIGS.
In the example of No. 8, the head support 100 and the ion generator support 1
46 is also configured to mesh with each other. Therefore, it has the feature that positioning can be performed more accurately. Furthermore, Figure 5
7 and FIG. 58 are different in the cross-sectional shape of the ion generator support 146, with FIG. 57 being a trapezoid and FIG. 58 being a rectangle. A notch is formed in the head support 100 so that these cross sections can be just accommodated.

[0222] As described above, by separating the main body of the ion flow recording head 3 and the ion generator 20, only the ion generator 20 can be replaced, so maintenance costs can be reduced. Economical.

In the above embodiment, one ion passage hole 29 is provided for each pixel, but the ion passage hole 29 formed in at least one of the first and second control electrodes 32 and 33 The hole may be composed of multiple holes. below,
Examples thereof are shown in FIGS. 59 to 64. 59 to 61 are enlarged views showing the vicinity of one ion passage hole 29 of the control board 30, in which (a) is a plan view and (b) is a (
A sectional view taken along line A-A' in a) is shown.

In the embodiment of FIG. 59, the first control electrode 32
The ion passage hole 29 of the second control electrode 33 is composed of one hole, whereas the ion passage hole 29' of the second control electrode 33 is composed of many small holes. In this case, the second control electrode 33 only needs to have a structure in which fine holes 29' are formed over the entire surface.

[0225] By configuring the ion passage hole 29 with a large number of fine holes 29' in this way, even if several holes 29'
Even if the holes become clogged due to the entry of developer such as toner into the holes, some holes remain that are not clogged, so ions can pass through the ion passage holes that are not clogged, and an image can be recorded. can do. On the other hand, if the ion passage hole 29 is made up of one large hole, once clogging occurs, the corresponding pixel will no longer be recorded. By configuring the ion passage hole 29 from a large number of thin holes in this way,
Image quality deterioration due to clogging can be controlled.

In the embodiment of FIG. 60, the first control electrode 32
This is an example in which the electrodes are individual electrodes, and the ion passage holes formed therein are a large number of fine holes 29', which is the opposite of the embodiment shown in FIG. A second control electrode 33 is formed on the opposite side of the first control electrode 32 with the insulating substrate 31 in between. One large ion passage hole 29 is formed in the second control electrode 33 for each pixel.

[0227] In this way, the first control electrode 32 and the second control electrode 32
Even if the control electrode 33 is reversed, the effect on the problem of clogging of the ion passage hole by toner etc. remains basically the same. However, considering that the toner comes from the recording medium 1 side, that is, the second control electrode 33 side,
The embodiment shown in FIG. 59, in which the ion passage hole provided in the second control electrode 33 is composed of a large number of fine holes 29', is better than the control board 3.
It is thought that the toner is less likely to enter the inside of the 0, which is more effective.

The manufacturing process for the control board 30 having the configuration shown in FIGS. 59 and 60 may be the same as the method described using FIG. 38 or FIG. 50. That is, for example, a thickness of about 100
A double-sided copper-clad board is prepared, in which copper foil of about 18 μm is stretched on both sides of an insulating substrate 31 made of a polyimide sheet of about μm, and the copper foil of the second control electrode 33 is etched. A passage hole 29 is formed. Next, the insulating substrate 31 is further etched to form ion passage holes 29 in the insulating substrate 31 as well. here,
The second control electrode 33 is plated with gold so as not to be etched. Finally, a pattern for the first control electrode 32 and a large number of small ion passage holes 29' are formed by etching. Note that it is desirable that the first control electrode 32 is also plated with gold so that it is not damaged by ions.

In the embodiment shown in FIG. 61, a large number of fine ion passage holes 2 are provided in both the first and second control electrodes 32 and 33.
9' is formed. In this way, the first control electrode 3
2 is an individual electrode, which has many fine ion passage holes 29'.
is formed, and the opposite side of the insulating substrate 31 is a second control electrode 33 consisting of a common electrode, and this second control electrode 33 is also formed with a large number of fine ion passage holes 29'. . In the example in this figure, 3 pixels per pixel.
Seven small ion passing holes 29' correspond to each other, and ions pass through these small ion passing holes 29' to form an electrostatic latent image on the recording medium 1. In this embodiment, as in the embodiments shown in FIGS. 59 and 60, even if some of the ion passage holes 29' become clogged with toner or the like, many unclogged holes remain. This makes it possible to minimize image quality deterioration.

[0230] As an example, the size of one pixel is approximately 10
0 μm, whereas the diameter of the small ion passage hole 29' is about 10 μm. Here, assuming that the thickness of the insulating substrate 31 is about 100 μm as in the above example,
Fine ion passage holes 29 as shown in FIGS. 59 to 61
′ is difficult to form by etching. However, when considering the controllability of ions, it is most efficient if the thickness of the insulating substrate 31 is approximately the same as that of the ion passage holes 29'. Therefore, in this case, it is desirable that the thickness of the insulating substrate 31 is approximately 10 μm, which is about the diameter of the ion passage hole 29', and it is possible to form such a control substrate 30 by etching.

In FIGS. 59 to 61, a large number of small ion passing holes 29' are all shown to have a round shape, but
Its shape is not limited to circular. Since the circular pattern is the simplest, it has the advantage of being easy to make. However, when forming a large number of ion passage holes 29' by etching,
Since the line width of the portion left to prevent adjacent holes from connecting with each other is not constant, ions cannot necessarily pass through efficiently. Therefore, FIG. 62 shows other examples of the ion passage holes 29'; (a) is a hexagonal example;
In addition, (b) shows an example of a rectangular shape. By using polygonal ion passage holes in this manner, the distance between adjacent ion passage holes can be made constant. Therefore,
Under these conditions, the area of the ion passage holes 29' can be made larger than in the case of a circular shape, as long as the adjacent holes are separated by a sufficient distance so that they are not connected to each other by etching or the like. In other words, when the ion passage hole is polygonal, the area through which ions pass can be larger than when the ion passage hole is circular, so more efficient recording can be achieved.

As shown in FIGS. 59 and 60, one of the control electrodes 32 or 33 is a solid electrode common to the entire surface, and the solid electrode has many small ion passing holes 2.
If 9' is formed, the control board 30 may be manufactured by a method different from the method described above. For example, the case of FIG. 59 will be explained. In this case, first, a single-sided copper-clad board in which copper foil is pasted on one side of the insulating board 31 is used. This substrate is etched to first form the first control electrode 32, and further etched to form the insulating substrate 31.
An ion passage hole 29 is formed in. A control board 30 as shown in FIG. 59 can be manufactured by attaching a copper foil having a large number of small ion passage holes 29' formed thereon by etching or the like over the entire surface of the control board 30 formed in this manner. In this case, the shape of the ion passage holes formed on the entire surface of the copper foil may be circular or polygonal.

Furthermore, there is also a method of using a mesh made of conductive fibers as shown in FIGS. 63(a) and 63(b) instead of the copper foil with a large number of holes. In other words, the first control electrode 32 and the ion passage hole 29 are formed as a single-sided copper-clad substrate, and the insulating substrate 31
The control board 30 is manufactured by attaching this mesh as the second control electrode 33 to the surface opposite to the first control electrode 32 with the mesh in between. FIG. 63(a) is an example of a mesh formed by weaving conductive thin threads in the vertical and horizontal directions, and an enlarged view thereof is shown in FIG. 63(b). FIG. 63(c) is yet another example of a mesh.

[0234] By using such a mesh, the control board 30 can be realized at low cost through simple steps. As an actual example, if we knit a mesh like the one shown in Figures 30(a) and (b) using stainless steel thread with a thickness of about 10 μm, it is possible to form square ion passage holes with a side of about 10 μm. It is. In this example, the second control electrode 33 is a metal mesh, but the first control electrode 32 may also be used.

FIG. 64 shows yet another embodiment. In the previous embodiment, the ion passing holes 29 cannot be arranged in a straight line as shown in FIG. 37, but are arranged diagonally in groups of four. Furthermore, the lead wires connected to the control electrodes in which the ion passage holes 29 are formed are divided into two wires, one above the other (on both sides in the sub-scanning direction). Therefore, the ion flow recording head 3 has no choice but to have a three-dimensional structure as shown in FIGS. 26, 27, and 55 to 58.

[0236] In other words, when attempting to make a flat plate-shaped ion flow recording head, since the ion passage hole 29 would be formed in the center of the substrate, other devices would be placed on both sides of the recording drum 1 around the head. This greatly increases the space in which it cannot be placed, which is disadvantageous to downsizing the device. Therefore, an ion flow recording head 3 having a three-dimensional structure is required. However, from a manufacturing standpoint, a flat head is much simpler. Furthermore, when the ion passage holes 29 are arranged as shown in FIG. 26, it is necessary to electrically control each individual control electrode in a complicated manner using a signal delayed by many lines in the sub-scanning direction. No. Furthermore, the scale of memory and other circuits used for processing such as signal distribution, rearrangement, and delay increases.

Considering the above circumstances, it can be said that an ideal ion flow recording head has the ion passing holes 29 lined up in a row and the control electrode lead wires being led out to only one side. By doing so, the ion passage hole 29 can be provided on the end face of the head, so that the device can be made smaller.

The reason why the ion passing holes 29 are not arranged in a line as shown in FIG. 26 is based on the recording resolution and the manufacturing accuracy of the control electrode and the ion passing holes 29, as described above. In other words, the limit that can be produced by etching is, for example, 25 μm.
pattern, 25 μm space, 100 μm
It is impossible to form ion passing holes in a row at a pitch of 100 μm. Therefore, as shown in FIG. 26, a configuration was adopted in which ion passage holes 29 are arranged diagonally. On the other hand, when the control board 30 having the configuration as shown in FIG. 60 or 61 is used, an ion flow recording head having the structure as shown in FIGS. 64(a) and 64(b) can be constructed, for example. . That is, for example, it is slightly less than 100 μm, but almost 100 μm.
This makes it possible to arrange the control electrodes 32 or 33 in a row at a pitch of μm.

FIG. 64(a) shows an example in which the first control electrode 32 is square, and FIG. 64(b) shows an example in which the first control electrode 32 is circular. In either case, a large number of small circular ion passage holes 29' are formed. By using such a large number of small ion passing holes 29', it is possible to arrange the ion passing holes in a line in the main scanning direction. Furthermore, since the first control electrode 32 can be formed close to the end surface of the ion flow recording head 3, the recording drum 1
It will also be possible to greatly contribute to the miniaturization of devices.

[0240]

[Effects of the Invention] According to the present invention, the following effects can be obtained.

(1) It is possible to control the ion flow according to the image signal with a low voltage of about ~60V, and thereby achieve a low voltage of the drive circuit, so the mounting area is the same as the drive voltage of the thermal head. It becomes possible to use a driver IC with a small size, and it is possible to use an IC, downsize, and increase the definition of the recording head.

(2) By making the width of the ion passage hole in the main scanning direction larger than the width in the sub-scanning direction, a decrease in resolution in the sub-scanning direction can be prevented.

(3) By arranging a predetermined plurality of ion passing holes diagonally at an angle θ with respect to the main scanning direction, the pitch of the ion passing holes in the main scanning direction can be easily reduced, and the pitch of the ion passing holes in the main scanning direction can be easily reduced. High-resolution recording becomes possible under the high electrode formation accuracy.

(4) By drawing out the lead wires from the control electrodes to both sides in the sub-scanning direction, it is possible to drive each control electrode simultaneously instead of the conventional matrix drive, and it is possible to drive each control electrode individually. It will be possible to drive. This makes it possible to control the gradation for each pixel even during high-speed recording.

(5) When ion passing holes are arranged on the end surface of the recording head,
In the recording drum, which is a recording medium, it is sufficient that only the width of the end surface of the recording head is in contact with the recording head, so that the recording drum can be downsized, and the entire recording apparatus can be downsized.

(6) By configuring the ion generator to be detachable from the ion flow recording head, even if the ion generator deteriorates and the amount of ions generated decreases, the entire ion flow recording head can be removed. Since there is no need to replace the ion generator and only the ion generator needs to be replaced, the driving IC mounted on the head can be used as is.

(7) When a plurality of ion passing holes are formed in at least one of the first and second control electrodes for one image point, some of the ion passing holes are exposed to the developing toner, etc. Even if clogging occurs, ions can pass through other ion passage holes that are not clogged, so pixels can be recorded. This makes it possible to extend the life of the ion flow recording head.

[0248]

[Table 1]

[0249]

[Table 2]

0250]

[Math 1]

[0251]

[Math 2]

0252]

[Math 3]

0253]

[Math 4]

[Brief explanation of the drawing]

[Fig. 1] A cross-sectional view showing a schematic configuration of an electrostatic recording device to which the present invention is applied.

[Fig. 2] A cross-sectional view showing a schematic configuration of another electrostatic recording device to which the present invention is applied.

[Fig. 3] A diagram schematically showing the configuration of an embodiment of the ion flow recording head used in the present invention.

[Fig. 4] Cross-sectional view showing the configuration of a printer to which the present invention is applied

[Figure 5] Diagram showing the ion measurement system

[Figure 6] Diagram showing the relationship between AC voltage frequency and ion current of the same ion flow recording head

[Figure 7] A diagram showing the relationship between the ion generation electrode of the same ion flow recording head and the potential distribution when it is replaced with a wire.

[Figure 8] Diagram showing the relationship between the wire diameter and the critical electric field for ion generation in Figure 7

[Figure 9] A diagram showing the relationship between the thickness of the insulating layer and the ionization area in the same ion flow recording head.

[Figure 10] A diagram showing the relationship between the insulating layer thickness and the ion generation critical voltage in the same ion flow recording head.

[Figure 11] Diagram showing the relationship between slit width and ionization area in the same ion flow recording head

[Figure 12] Diagram showing the relationship between slit width and ion generation critical voltage in the same ion flow recording head

[Figure 13]
Diagram showing the relationship between applied AC voltage and potential distribution in the same ion flow recording head

[Figure 14] Diagram showing the relationship between bias voltage and potential distribution in the same ion flow recording head

[Figure 15] Diagram showing the relationship between bias voltage and ion current in the same ion flow recording head

[Figure 16] Diagram showing the relationship between AC voltage frequency and ion generation virtual surface in the same ion flow recording head

[Figure 17]
Diagram showing the relationship between AC voltage and ion current in the same ion flow recording head

[Figure 18] Diagram showing the potential distribution of each part in the same ion flow recording head

[Figure 19] Diagram for explaining parameters related to the ion flow recording head

[Figure 20] Diagram showing the relationship between control voltage and ion current in the ion flow recording head

[Figure 21] Diagram showing the ion current measurement system of the ion current recording head

[Figure 22] A diagram showing the relationship between the ion current recording head and the ion current/surface potential near the recording medium.

[Figure 23] Diagram for explaining the ion trajectory near the control electrode in the same ion flow recording head

[Figure 24] Diagram showing ion current/surface potential in the same ion flow recording head

[Figure 25] Diagram showing ion current/surface potential at critical speed in the same ion flow recording head

FIG. 26 A cross-sectional view of an embodiment of the ion flow recording head used in the present invention.

[Figure 27] Side view of the same ion flow recording head

[Figure 28
] A perspective view showing the configuration of the main parts of the ion flow recording head.

[Figure 29] A plan view showing the schematic configuration of the ion generator in the ion flow recording head.

[Figure 30] Top and back views of the ion generator

[
Figure 31: Cross-sectional view taken along line A-A' in Figure 29

[Figure 32
] Enlarged view of part B in Figure 29

[Figure 33] Figure 2
Enlarged view of part C in 9

[Figure 34] Block diagram showing the configuration of the driver IC used in the present invention

[Figure 35] A plan view of the control board in the ion flow recording head used in the present invention seen from the front side.

[Figure 36] Plan view of the control board seen from the back side

[Figure 3
7] Enlarged view of the vicinity of the ion passage hole on the same control board

[Figure 3
8] Process cross-sectional diagram for explaining the manufacturing method of the control board

[Figure 39] Plan view for explaining the positioning method when integrating the control board and the ion generator.

[Figure 40
] Another plan view for explaining the positioning method when integrating the control board and the ion generator.

[Figure 41]
Cross-sectional view taken along line D-D' in FIG. 28

FIG. 42 A diagram schematically showing the configuration of another embodiment of the ion flow recording head used in the present invention.

[Figure 43] A perspective view of an ion flow recording head having the basic configuration shown in Figure 42.

[Figure 44] Cross-sectional view along line E-E' in Figure 43

[Figure 4
5] A perspective view showing another example of the ion flow recording head having the basic configuration of FIG. 42.

[Figure 46] Cross-sectional view along line FF' in Figure 45

[Figure 4
7] Plan view showing the shape of the ion passage hole and the control electrode around it in the ion flow recording head used in the present invention

FIG. 48 A plan view showing another example of the shape of the ion passage hole and the control electrode around it in the ion flow recording head used in the present invention.

FIG. 49 A plan view showing still another example of the shape of the ion passage hole and the control electrode around it in the ion flow recording head used in the present invention.

FIG. 50: Process cross-sectional diagram for explaining another method of manufacturing the control board in the ion flow recording head used in the present invention.

FIG. 51 A plan view for explaining the method for drawing out the control electrode lead wiring in the ion flow recording head used in the present invention.

FIG. 52 A diagram schematically showing the configuration of another embodiment of the ion flow recording head used in the present invention.

FIG. 53 is a diagram schematically showing the configuration of yet another embodiment of the ion flow recording head used in the present invention.

FIG. 54 is a plan view for explaining another positioning method when integrating the control board and the ion generator in the ion flow recording head used in the present invention.

FIG. 55 is a diagram showing another configuration example of the end face type ion flow recording head used in the present invention.

FIG. 56 is a diagram showing still another configuration example of the end face type ion flow recording head used in the present invention.

FIG. 57 is a diagram showing another configuration example of the end-face type ion flow recording head used in the present invention.

FIG. 58 is a diagram showing still another configuration example of the end face type ion flow recording head used in the present invention.

FIG. 59 A plan view and a cross-sectional view of a control board having a large number of ion passage holes per pixel in the ion flow recording head used in the present invention.

FIG. 60 is a plan view and a cross-sectional view of another example of a control board having a large number of ion passage holes per pixel in the ion flow recording head used in the present invention.

FIG. 61 A plan view and a cross-sectional view of still another example of a control board having a large number of ion passage holes per pixel in the ion flow recording head used in the present invention.

[Figure 62] Plan view showing other examples of shapes of ion passage holes

[Figure 63] Diagram showing an example of ion passage holes formed by metal mesh

[Fig. 64] Plan view for explaining an example in which control electrodes are arranged in a row.

FIG. 65 is a cross-sectional view schematically showing the configuration of a conventional ion flow recording head.

[Explanation of symbols]

1... Recording drum (recording medium)
3...Ion flow recording head 20...Ion generator
21... Insulating substrate 22... Induction electrode
23...Insulator layer 24...Ion generation electrode
25... Shield electrode 26... Slit
28... Spacer member 29, 29'... Ion passage hole
30...Control board 31...Insulating board
32...First control electrode 33...Second control electrode
34...Control voltage 37...Bias voltage
39...AC voltage 41...Al drum (conductive base) 42
…Dielectric layer 50…Flexible cable 5
1...Positioning pattern 52...Adhesive injection hole
53, 54...Terminal 55, 56...Metal layer
57...Blower hole 58...Cutout pattern for alignment 59...Bar pattern for alignment 60...Flexible cable connection terminal 78...Head holder 79...Bonding wire
100...Head support body 103...Drive circuit board
104...Blower hole 124...Driver IC
146...Ion generator support

Claims (12)

[Claims] 1. Forming an electrostatic latent image by irradiating ions onto a recording medium formed by forming a dielectric layer on a conductive substrate,
In an electrostatic recording device that records an image by developing this electrostatic latent image, an ion generating means includes at least two electrodes arranged in close proximity and generates ions by applying a voltage between these electrodes. and first and second control electrodes that are arranged at a predetermined interval between the ion generating means and the recording medium and each having an ion passage hole for passing ions generated from the ion generating means; An electrostatic recording apparatus characterized by comprising: a driving means for applying a predetermined potential difference to the first and second control electrodes in order to control the amount of ions passing through the ion passage hole according to an image signal. . 2. An electrostatic latent image is formed by irradiating ions onto a recording medium formed by forming a dielectric layer on a conductive substrate in a main scanning direction and a sub-scanning direction perpendicular to the main scanning direction. , an electrostatic recording device that records an image by developing this electrostatic latent image, which includes at least two electrodes placed in close proximity, and when a voltage is applied between these electrodes, ions are generated by corona discharge. ion generating means disposed along the main scanning direction to generate ions; and ion generating means disposed at a predetermined interval between the ion generating means and the recording medium and arranged along the main scanning direction; a plurality of first and second control electrodes each having an ion passage hole for passing ions generated from the control electrode;
The static control device further comprises driving means for selectively applying a predetermined potential difference to the first and second control electrodes in order to control the amount of ions passing through the ion passage hole in accordance with an image signal. Electric recording device. 3. The distance between the ion generating means and the first control electrode is larger than the distance at which the strength of the leakage electric field from the ion generating means is equal to or higher than the discharge starting electric field of air. The electrostatic recording device according to claim 1 or 2. 4. Means for regulating the amount of ions passing through the first and second control electrodes and reaching the recording medium to 1/2 or less of the amount of ions generated by the ion generating means. The electrostatic recording device according to any one of claims 1 to 3, further comprising the following. 5. The driving means is configured to drive the first and second
A fixed potential equal to the potential of the conductive substrate is always applied to one of the control electrodes, and a potential higher or lower than that of the other electrode is applied to the other electrode, depending on the polarity of the ions. Claims 1-1 characterized in that a potential is applied.
4. The electrostatic recording device according to any one of 4. 6. The driving means is configured to drive the first and second
A fixed potential higher than the potential of the conductive substrate is always applied to one of the control electrodes, and a potential higher than or equal to the potential of the one electrode is applied to the other electrode of the first and second control electrodes depending on the polarity of the ions. The electrostatic recording device according to any one of claims 1 to 5, characterized in that a low potential is applied. 7. The electrostatic recording device according to claim 2, wherein the width of the ion passage hole in the main scanning direction is larger than the width in the sub-scanning direction. 8. The ion passing holes are arranged in the direction of an angle θ with respect to the main scanning direction such that θ=tan−1N (N is a ratio of the pitch in the sub-scanning direction to the pitch in the main scanning direction). The electrostatic recording device according to any one of claims 2 to 7, characterized in that: 9. An electrostatic latent image is formed by irradiating ions onto a recording medium formed by forming a dielectric layer on a conductive substrate in a main scanning direction and a sub-scanning direction orthogonal thereto. , an electrostatic recording device that records an image by developing this electrostatic latent image, which includes at least two electrodes arranged in close proximity, and when a voltage is applied between these electrodes, ions are generated by corona discharge. ion generating means disposed along the main scanning direction to generate ions; and ion generating means disposed at a predetermined interval between the ion generating means and the recording medium and arranged along the main scanning direction; a plurality of first and second control electrodes each having an ion passage hole for passing ions generated from the control electrode;
In order to individually control the amount of ions passing through the ion passage hole according to the image signal, one of the first and second control electrodes is set at a fixed potential, and the other electrode is set at a predetermined potential with respect to the one electrode. drive means for selectively applying a potential having a potential difference of An electrostatic recording device characterized by: 10. The ion generating means, the first and second control electrodes, and the driving means are integrally formed as a recording head on a head support, and the ion passage hole is located at an end surface of the head support. The electrostatic recording device according to any one of claims 1 to 10, characterized in that: 11. The ion generating means, the first and second control electrodes, and the driving means are integrally configured as a recording head, and the ion generating means is configured to be detachable from the recording head. The electrostatic recording device according to any one of claims 1 to 11, characterized in that: 12. A plurality of at least one of the ion passage holes formed in the first and second control electrodes is formed for each pixel formed on the recording medium. The electrostatic recording device according to any one of claims 1 to 12, characterized by: