JPH0451054A - Electrostatic recordor - Google Patents

Abstract

PURPOSE:To stably form a recorded image of a high resolution by facing a recording electrode and a cylindrical electrode also serving as an intermediate recording medium installed in parallel with minimum spacing in between them on a developer carrier member and impressing AC bias voltage on the cylindrical electrode. CONSTITUTION:This recorder is provided with a developer carrying member 14, a developer carrying means Uw carrying developer d along the surface of the former, the multiple number of recording electrodes 20a installed in parallel retaining electrical insulation with each other on the surface of the developer carrier member 14 at the specified intervals, the cylindrical electrode 5 installed facing the former at a specified interval and a recording electrode driving means 21 impressing recording voltage responding to the recording information on each recording electrode 20a. Furthermore, a bias power source 5a impressing bias voltage to the cylindrical electrode 5, and a voltage control means controlling recording voltage and the bias voltage are provided. Thus, normal paper can be utilized and a bright image of the high resolution can also be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a non-contact electrostatic recording device that forms an electrostatically recorded image without bringing a recording head into contact with a recording medium.

[Prior art and its problems]

Conventionally, a multi-stylus printer is well known as one of electrostatic recording devices. This multi-stylus printer constructs a recording head by arranging a large number of needle-shaped recording electrodes at evenly spaced intervals in the main scanning direction, and selectively applies voltage to each needle-shaped electrode according to the recording signal to print on the paper. An electrostatic latent image is formed by direct discharge. In this case, special paper coated with a high electrical resistance agent is used so that charges can be easily and stably retained on the paper. However, such special paper is not easy to write on with a boat or a pen, and also has problems with its shelf life as it deteriorates depending on environmental conditions such as humidity.
Not suitable for office paper.

Furthermore, if the distance between the tip of the needle electrode and the paper surface is large, the discharge electric field will spread and the formed dots will become large, making it difficult to obtain a high-resolution recorded image.

Therefore, a minute gap is secured by providing a gap material on the surface of the paper and bringing the tip of the needle electrode into sliding contact with the gap material. However, when using this method, there is a problem that the tip of the needle electrode is worn out.

Therefore, as a method that can use plain paper and accurately ensure a minute distance between the image medium and the tip of the recording electrode, first, a toner image is formed on a drum-shaped intermediate recording medium, and the toner image is A method is used in which the image is transferred onto paper. In this method, the apparatus tends to become larger due to the use of an intermediate recording medium.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and is a compact and highly durable static device that can use plain paper and stably obtain clear images with high resolution. The purpose is to provide an electronic recording device.

[Key points of the invention]

The above object is to provide a developer carrying member whose surface serves as a developer carrying path, a developer carrying means for carrying the developer along the surface of the developer carrying member, and a developer carrying member that is arranged on the surface of the developer carrying member at a predetermined interval from each other. A plurality of recording electrodes arranged in parallel while maintaining electrical insulation, a cylindrical electrode arranged opposite to the recording electrodes with a predetermined gap, and a recording electrode drive that applies a recording voltage according to recording information to each of the recording electrodes. a bias power supply for applying a bias voltage to the cylindrical electrode, and a voltage control means for controlling the recording voltage and the bias voltage, and the voltage control means is configured to apply the recording voltage to the cylindrical electrode outside the recording time. This is achieved by providing an electrostatic recording device characterized in that a cleaning voltage is applied to forcibly transfer the developer on the recording electrode side to the cylindrical electrode.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 10.

FIG. 1 is a schematic cross-sectional view showing the overall configuration of a recording apparatus as an embodiment of the present invention. In the figure, reference numeral 1 denotes a paper feed cassette loaded with cut sheets P of plain paper, which is detachably mounted on the side of the machine. A paper feed roller 1a is arranged above the tip of the inserted paper feed cassette 1 so as to be rotatable in the direction of the arrow. In front of the paper feed roller 1a, a paper transport path is defined by upper and lower transport guide plates 2a+2b made of insulating members. A pair of standby rolls 3 is arranged in this paper transport path, and a paper feed roller
After the advance of the paper P that has been fed out is temporarily stopped and the transport attitude is adjusted, the paper P is fed again to the image transfer section T on the downstream side in synchronization with the arrival timing of a recorded image, which will be described later.

In the image transfer section T on the downstream side of the standby roll pair 3, a transfer charger 4 is arranged facing a cylindrical electrode S which also serves as an image carrier.

In this example, the cylindrical electrode 5 is driven to rotate in the counterclockwise direction indicated by arrow a. As will be described later, this cylindrical electrode 5 uses a developer with negative (-) friction charging polarity in this example, so an AC bias voltage obtained by superimposing an AC voltage on a negative DC voltage is applied to the cylindrical electrode 5. AC bias power supply 5a that can output
Connect it. In this case, the frequency of the AC bias voltage is set to 10 kHz or more. In this manner, by applying a high-frequency AC bias voltage to the cylindrical electrode, a recorded image without background smudge and with sufficient image density can be obtained. The reason for this will be made clear in the explanation of the recording operation described later.

On the circumferential surface on the opposite side of the cylindrical electrode 5, recording image forming plates (U) U, which will be described later, are arranged to face each other. A toner recorded image is formed on the surface of the cylindrical electrode 5 by this recorded image forming unit U, and as the cylindrical electrode 5 rotates, the toner recorded image is conveyed to the image transfer section T, and is re-fed (transferred onto a sheet of paper). The configuration of the recording image forming unit U will be explained in detail from the rear frame.

On the downstream side of the image transfer section T, a separating claw 6 is disposed with its tip pressed against the circumferential surface of the cylindrical electrode. On the downstream side of the separation claw 6, an air sling type conveyor belt 7 is stretched in the horizontal direction, and after transferring the recorded image, the separation claw 6
The back surface of the sheet separated from the circumferential surface of the cylindrical electrode 5 is sucked and conveyed toward the fixing device 8 provided in front of the sheet. The fixing device 8 consists of a heating roll 8a and a pressure roll 8b, and thermally fixes the toner image when the paper is held between the two rolls and conveyed. After the fixing, the sheets are discharged from the discharge port 9 and stacked on the paper discharge tray 10 in a face-down state with the image side facing down.

As described above, in the recording apparatus of this example, the entire paper transport path from paper feeding to paper ejection is formed in a substantially straight shape, so the paper feeding operation is generally smooth, and image defects are avoided. Paper feeding defects such as jams are less likely to occur. It also has the advantage that the above-mentioned straight sheet passing path can achieve a face-down sheet discharge state that does not require page alignment, which is preferable for the recording apparatus.

Here, the detailed configuration of the recording image forming unit U will be explained.

The recording image forming unit) U generally has a stirring roll 12 and a supply roll 13 rotatably disposed at the bottom of a unit container 11 for storing developer, and integrates an image recording means and a developer conveying means. The recording unit Uw is arranged in such a manner that its recording head portion is located in an opening 11a of a container 11 that is open toward the circumferential surface of a cylindrical electrode 5. In this example, an insulating magnetic toner is used as the developer, which is a one-component developer containing at least an insulating resin, magnetic fine powder, and colorant particles, and has negative (-) triboelectric charging characteristics. Incidentally, as the developer, a two-component developer in which a magnetic material, a middle layer, and an insulating toner are mixed in a predetermined ratio can also be used.

FIG. 2 is a schematic cross-sectional view showing the recording unit Uw and its peripheral members. The recording unit UwN of this example has a columnar body with an oval cross section and extending in the direction perpendicular to the plane of the paper.
Base 1 made of a high magnetic permeability material such as nickel or permalloy
An outer cover member 15 made of a non-magnetic material and whose surface serves as a conveying path for the magnetic toner d covers a region other than a part of the outer circumferential surface of the magnetic toner 4. On the peripheral surface of the base body 14 covered with the outer sheathing member 15, a large number of concave grooves 14a having a V-shaped cross section are formed in parallel and at equal intervals along the longitudinal axis direction of the base body (direction perpendicular to the plane of the paper). It is. In the second FllJ, only a total of 12 recess grooves 14a are shown, but in reality, more recesses #14a are formed densely.

The length of each turning groove 14a is set to be longer than the width of the conveying path defined on the circumferential surface of the outer cover member 15.

A conducting wire lea is buried and laid in each circuit groove 14a,
A fill portion 16 is formed as a part of the excitation coil. As shown in FIG. 3(a), this coil portion 16 is
In this example, it is divided into two groups, A and B, and each group's coil portion 16A,
16B are arranged every l pieces. In this case, Figure 3 (
As shown in b), a pair of fill sections 16.16 adjacent to each other with one coil section 16 in the other group in the same group (for example, consecutive odd-numbered and even-numbered coil sections with the coil section 16B1 16A1 and 16A2) are the same conductor 16a
It is formed by winding it many times in a predetermined direction across every other pair of concave grooves 14a, 14a. Therefore, the running directions (based on the winding direction of the coils) of the conducting wires 18a of every other pair of adjacent coil portions 16.16 in the same group are opposite to each other.

In addition, when dividing the coil part 1θ into m&l of 3M or more, 1
The coil parts of each set are arranged every (m-1) pieces, and the conductor lea is placed in a pair of recessed grooves 14a, 14 every (m-1) pieces.
a to form a pair of coil parts of the same set.

As shown in FIG. 4, two types (two phases) of alternating current AllB 1^= whose phases are shifted by π/2 are applied to the fill section 4A of group A and the coil section 4B of group B configured as described above. I sin (ωt) ・・・・・・・・・
... (1) ia=Isin(ωt+z/2)++
+++ (2) are respectively energized.

By applying an alternating current to each coil portion 16 as described above, a magnetic field corresponding to the applied current as shown in FIG. 5 is excited in each partition portion 14b between each concave groove 14B in the base body 14. . FIG. 5 is a graph showing temporal changes in the excitation magnetic field distribution on the surface of the sleeve 2. FIG. In the graph, the vertical axis represents the sleeve radial component Hr of the excitation magnetic field, and the horizontal axis represents the position on the surface of the sleeve 2. Note that T is the period of the alternating current that is applied. In this example, as described above, the running directions of the conducting wires in the odd-numbered and even-numbered coil portions 16 (for example, 1BAI and 16A2) in each set are reversed. Therefore, the same coil part 16
If an alternating current with the same phase is passed through the coils, the directions of the magnetic fields excited by the odd-numbered and even-numbered coil portions 1θ will be opposite to each other. As a result, the distribution curve of the magnetic field formed on the surface of the sleeve 2 also draws a waveform corresponding to the alternating current as shown in FIG. Since this waveform magnetic field changes with a period T like an alternating current, it results in the formation of a traveling wave magnetic field that travels in a convex direction in the figure.

That is, in FIG. 3(a), the waveform magnetic field formed on the surface of the sleeve 2 by all the coil portions 16 travels counterclockwise along the surface of the jacket member 15 at a predetermined speed. As a result, the magnetic toner can be conveyed to the port in the clockwise direction opposite to the traveling direction A of the traveling wave magnetic field. In this case, as shown in FIG. 2, the magnetic toner d is conveyed while forming toner spikes corresponding to the lines of magnetic force of the traveling wave magnetic field.

Returning to FIG. 2, in this example, the base body 14 is separably divided into two parts, and the internal space S is formed by joining the divided base bodies 14A and 14B. Each divided base 1
4A and 14B are individually covered with outer cover members 15A and 15B. In order to form a flat toner conveyance path, 15 people worked on both outer covers.

A bridge member 17 is installed at the joint portion of 15B.

On the upstream side of the toner conveyance path, there is a doctor blade 18 for regulating the toner spikes to an appropriate length to form a toner layer.
It is arranged. The doctor blade 18 of this example is fixed to the side wall of the unit container 11 with its tip brought close to the surface of the outer cover member 15B. On the downstream side of the doctor blade 18, the position where the circumferential surface of the outer sheath member 15A is closest to the surface of the cylindrical electrode 5 with a small gap is the recording part W, where the magnetic toner d is applied to the surface of the cylindrical electrode 5 according to input recording data. The toner is selectively transferred to form a toner recorded image. On the downstream side of the recording section W, a scraping plate 19 is installed, and its tip is connected to the outer cover member 1.
It is placed in pressure contact with the 5A surface. This scraping plate 19 scrapes off the residual magnetic toner d' that has been conveyed without being used in the recording section W.

On the surface of the outer covering member 15A, a recording electrode sheet 20 is adhered and laid in an area upstream from the recording section W with respect to the toner transport direction opening. The recording electrode sheet 20 of this example has the sixth
As shown in the figure, a plurality of recording electrode lines 20a, which are made of a visible printed circuit board (FPC) and extend parallel to each other in the sheet longitudinal direction, are placed on the base film 2Ob in the sheet width direction (toner transport path width direction). : are formed extending in parallel at a predetermined fine pitch in the main scanning direction). This recording electrode wire 20
The number a corresponds to the maximum number of data for one main scanning line. In this example, a large number of recording electrode lines 20a are
The pattern was formed by etching at a density of 86 μm pitch (300 DPI) with a spacing of m.

The recording electrode sheet 20 configured as described above is submerged below the bridge member 17, as shown in FIG.
It passes through the joint surfaces of 4A and 14B and extends to the internal space S. Inside the internal space S, a plurality of drive circuit elements 21 are arranged to drive each recording electrode line 20a. The recording electrode wires 20a of the recording electrode sheet 20 described above are divided into appropriate numbers and connected to these drive circuit elements 21, respectively.

From each drive circuit element 21, the input wiring circuit 22 is connected to the recording unit Uw from the other joint surface of the divided bases 14A, 14B.
There is a drawer outside. The input wiring circuit 22 is connected to the recording control section C mentioned above. Therefore, the drive circuit element 21
is connected to a recording control section (not shown) that controls the recording operation of the entire recording apparatus.

Here, the recorded image forming operation in the recording apparatus of this example will be explained.

In Fig. 2, when the above-mentioned alternating current is applied to the excitation filter, a traveling wave magnetic field moving in the direction of arrow A is formed on the outer circumferential surface of the area where the excitation coils of recording units (U) and (W) are arranged. The magnetic toner d is conveyed in the opposite direction of the arrow while forming a spike (toner chain). The conveyed magnetic toner d is regulated to be cut to a predetermined thickness by the doctor blade 18, and then conveyed to the recording section W. At this time, the magnetic toner d is triboelectrically charged to a negative polarity.

In the recording section W, each recording electrode line 20a and the surface of the cylindrical electrode 5 face each other with a minute gap interposed therebetween, and this minute gap can be secured accurately and stably without providing a gap material or the like, so that high resolution can be achieved. It is possible to stably obtain recorded images using a non-contact method. Then, an electric field is formed in the minute gap according to the recorded information, and the magnetic toner d of the toner chain being conveyed is selectively attached to the circumferential surface of the cylindrical electrode 5 while the tip is brought into contact with the circumferential surface of the cylindrical electrode 5. Form a toner recorded image. The toner recorded image is formed as follows.

FIG. 7(a) is a timing chart showing the relationship between the recording voltage Vs applied to the recording electrode line 20a and the AC bias voltage Vd applied to the cylindrical electrode 5. FIG. Cylindrical electrode 5
Since the charged polarity of the magnetic toner d used in this example is negative, the alternating current bias power supply 5a generates a voltage between 0V and -50V.
An AC bias voltage Vd having a peak frequency of 10 kHz or more is applied. This AC bias voltage Vd is obtained by superimposing a high frequency AC voltage and a negative polarity DC voltage.

On the other hand, for the recording electrode line 20a, the drive circuit element 21
However, in this example, the voltage is -200V depending on the input recording data.
A recording voltage Vs varying between (on voltage) and 0V (off voltage) is applied. In this case, when one bit of recording data input to the drive circuit element 21 is "H", an on-voltage of -200V is applied to the corresponding recording electrode line 20a. As a result, a potential difference of 200V to 150V is created from the cylindrical electrode 5 to the recording electrode 120a.

Since the negatively charged magnetic toner d is attracted towards the higher potential, the recording electrode line 2 to which a voltage of -200V is applied is located in the recording section W where the interval is the narrowest and the electric field is the largest.
Only the magnetic toner d of the toner chain moving on Oa selectively adheres to the surface of the cylindrical electrode 5, forming a black dot.

When 1 bit of recorded data is “L”, recording electrode line 2
In this example, an off-voltage of 0V is applied to 0a. As a result, the potential difference seen from the cylindrical electrode 5 to its corresponding recording electrode line 20a becomes Ov~-50V, and the negative magnetic toner d does not adhere to the surface of the cylindrical electrode 5, which has a low potential, but remains retained as a toner chain. Move downstream.

By applying an alternating current bias voltage to the cylindrical electrode 5 as described above, the cylindrical electrode 5 has a voltage of -150 as shown in FIG. 7(b).
Compared to the case where the DC bias voltage Vd' of V is applied,
It is possible to stably form a good recorded image without background smudge and with sufficient image density. The reason is as follows.

When the toner chain moves in the recording section W, the magnetic toner at its tip is in contact with the surface of the circular TiTIi pole 5. Therefore, physical adhesion forces such as so-called mirror image force and Van der Waals force mainly act between the surface of the cylindrical electrode 5 and the magnetic toner in contact with the surface, and the magnetic toner tends to adhere to the surface of the cylindrical electrode 5. There is. When the recorded data is "L", if the magnetic toner adheres to the surface of the cylindrical electrode 5 due to the above-mentioned image force or the like, it appears as background stains on the image. In order to prevent this background stain from occurring, the bias voltage is applied to the cylindrical electrode 5.
is applied to apply a collection electric field force to cause the magnetic toner to separate from the surface of the cylindrical electrode 5.

However, according to the method of applying a constant DC bias voltage Vd' shown in FIG. The adhesion force acts on the cylindrical electrode 5.
The magnetic toner d that comes into contact with the surface adheres as it is, resulting in background stains.

On the other hand, as in this example, the high frequency AC bias voltage V
When d is applied to the cylindrical electrode 5, a collection electric field force acts on the magnetic toner intermittently in short cycles. In other words, a state similar to that obtained when high-frequency vibrations are applied to the magnetic toner is obtained. As a result, a toner cloud is formed in which the magnetic toner near the surface of the cylindrical electrode 5 stays in a floating state. The physical adhesion force such as mirror image force that acts on the magnetic toner in the toner cloud state is weaker than that on the magnetic toner that simply contacts the surface of the cylindrical electrode 5. Therefore, even when the amount of charge is large, the magnetic toner that forms the toner cloud does not adhere to the surface of the cylindrical electrode 5 and cause background stains, but rather due to the collection electric field force that acts intermittently and the magnetic force from the coil section 16. It moves downstream while being drawn toward the recording electrode line 2Oa side.

The inventors of the present invention have experimentally confirmed that the above-mentioned toner cloud is likely to occur when the frequency of the applied AC bias voltage is 10 kHz or more. This is because 50 μsec, which is 1/2 period of the above-mentioned 10 kHz wave, is the moving time of the magnetic toner between the electrodes, and for frequencies higher than that, the magnetic toner cannot move between the electrodes and is near the surface of the cylindrical electrode 5. This is because the toner moves back and forth, resulting in a toner cloud state.

When the recording data is "H", the ON recording voltage (-200V) is applied to the recording electrode line 20a, so even if the magnetic toner forms a toner cloud, the electric field force ensures that the surface of the cylindrical electrode 5 is It is possible to obtain sufficient image density.

The magnetic toner d' that remains without being transferred to the cylindrical electrode 5 side in the recording section W moves downstream with the progress of the traveling wave magnetic field and is scraped off from the surface of the jacket member 15A by the scraping plate 19, and the stored magnetic toner d' Stirred and mixed with toner.

The toner recorded image formed on the circumferential surface of the cylindrical electrode 5 is
As shown in the figure, as the cylindrical electrode 5 rotates in the counterclockwise direction a, the image is conveyed to the image transfer section T, where it is transferred onto a sheet of paper that is re-fed at a timing measured by a pair of standby rolls 3.

Next, other embodiments of the present invention will be described.

Note that the same components as those in the above embodiment are given the same reference numerals, and the explanation thereof will be omitted.

The embodiment shown in FIG. 8 uses a pair of magnet rolls 23 and 24 as the developer conveying means in the recording unit UW of the image forming unit UW. FIG. 9 is a schematic cross-sectional view showing in detail the image forming process section consisting of the recording unit Uw and the cylindrical electrode 5. As shown in FIG. 9, the recording unit UW of this example includes a pair of magnetic transport rolls 25 each containing magnet rolls 23 and 24.
, 26, and a recording electrode body 28 serving as a recording means is disposed between both magnetic transport rolls 25.2Et.

When both magnet rolls 23 and 24 are rotated at the same speed in the same direction indicated by the arrows, a composite rotating magnetic field is formed on the surface of the developer carrying member 27 by the resultant force of the magnetic forces of both magnet rolls 23 and 24. be done. This combined rotating magnetic field transports the magnetic toner d along the surface of the developer carrying member 27 in the direction of arrow C.

In the developer transport path along the surface of the developer carrying member 27, the recording portion W closest to the circumferential surface of the cylindrical electrode 5 has the recording electrode body 2
The tip surface of No. 8 is made to protrude. The recording electrode body 28
As shown in FIG. 0, a sheet having the same structure as the recording electrode sheet 20 of the above embodiment is adhered to the surface of a plate-shaped electrode support member 28a. A drive circuit element 29 is directly mounted on the recording electrode sheet 20.

In this example as well, as in the above embodiment, an AC bias power source 5a is connected to the cylindrical electrode 5 as shown in FIG. 9, and as shown in the timing chart of FIG. AC bias voltage Vd and recording voltage Vs are applied to the cylindrical electrode 5, respectively.
is applied to the recording electrode line 20a. As a result, the recording section W
A toner cloud is formed on the toner cloud, and it is possible to stably form a recorded image with sufficient image density without background smudge.

Further, the recording electrode body 28 as a recording means is connected to the recording unit 0.
Since the recording unit Uw is built in the recording electrode W, the recording unit Uw in which the recording electrodes are densely mounted can be made small and compact. Therefore, the size of the image forming process section consisting of the periphery of the cylindrical electrode 5 and the recording unit Uw is promoted, and the size of the non-contact electrostatic recording device using the intermediate recording medium (cylindrical electrode 5) is greatly promoted. becomes possible.

It should be noted that the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

For example, as the AC bias voltage applied to the cylindrical electrode 5, it is also possible to use a pulse waveform voltage that deviates from 0 V toward the charging polarity side of the developer.

Furthermore, the present invention is applicable not only to the case where linear recording electrodes are used as in the above-mentioned embodiments, but also to the case where recording electrodes are arranged in a dotted manner, such as the needle-like electrodes of a so-called multi-stylus printer. can do.

Furthermore, the present invention is also applicable to the case where a non-magnetic developer is used instead of a magnetic developer.

〔Effect of the invention〕

As described in detail above, according to the present invention, the recording electrodes arranged in parallel on the developer carrying member and the cylindrical electrodes that also serve as an intermediate recording medium are opposed to each other with a small gap, and an alternating current bias voltage is applied to the cylindrical electrodes. As a result, it is possible to stably and accurately secure a minute gap between the electrode facing portions, and also to make the developer near the surface of the cylindrical electrode float in the cloud. As a result, it is possible to ensure sufficient image density without background smearing and to stably form a high-resolution recorded image.

Furthermore, since the recording electrode drive circuit is installed within the developer conveyance means, the recording means in which a large number of recording electrodes and their drive circuits are densely mounted and the developer conveyance means can be compactly integrated, and the recording and Since development is performed at the same time, it is possible to downsize an electrostatic recording apparatus using an intermediate recording medium, which tends to be large. Therefore, it is possible to manufacture a non-contact type electrostatic recording device that is small and inexpensive and can stably form the above-mentioned good recorded images on plain paper.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the overall configuration of a recording apparatus as an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a recorded image forming unit and its peripheral configuration in the recording apparatus, and FIG.
Figures (a) and 3(b) are explanatory diagrams showing the configuration of the excitation filter in the recording device, respectively. Figure 4 is a graph diagram showing the waveform of the current flowing through the excitation filter. Figure 5 is the diagram of the excitation filter described above. A graph showing a temporal change in an excitation magnetic field distribution curve due to an excitation coil, FIG. 6 is a partially cutaway perspective view showing a recording unit in the recording image forming unit, and FIGS. 7(a) and 7(b), respectively. Timing charts showing voltage control operations in the recording apparatus and comparative examples thereof, FIG. 8 is a schematic sectional view showing another embodiment of the present invention, and FIG. 9 is an image forming process section in the other embodiment. FIG. 10 is a perspective view showing the recording electrode body of the image forming process section. 1... Paper feed cassette 3... Standby roll pair 4... Transfer charger 5... Cylindrical electrode 5a... AC bias [source 8... Fixing device 11... Unit container 12... - Stirring roll 14... Base bodies 14A, 14B... Divided base bodies 15.15A, 15B... Outer cover member 16... Fill portion 18... Doctor blade 19... Scraping plate 20... Recording electrode sheet 20a...Recording electrode wire 20b...Base film 21.29...Drive circuit element 22...Input wiring circuit 23.24...Magnet roll 27...Developer carrying member 28... ...Recording electrode body T...Image transfer section U...Recording image forming unit U, ...Recording unit W...Recording section

Claims (4)

[Claims] (1) A developer carrying member whose surface serves as a developer carrying path, a developer carrying means for carrying the developer along the surface of the developer carrying member, and a plurality of recording electrodes arranged on the surface of the developer carrying member. Installed in parallel with electrical insulation at intervals of
a recording means comprising a drive circuit installed inside the developer conveying means for outputting a recording voltage to each of the recording electrodes in accordance with recording information; and a cylindrical electrode disposed opposite to the recording electrode with a predetermined gap maintained therebetween. and by applying the recording voltage to an electrode facing part where the recording electrode and the cylindrical electrode face each other,
An electrostatic recording device that selectively transfers developer conveyed to the electrode facing portion to the cylindrical electrode side, characterized in that an alternating current bias voltage is applied to the cylindrical electrode. (2) The electrostatic recording device according to claim 1, wherein the AC bias voltage is formed by superimposing a DC voltage and an AC voltage. (3) The electrostatic recording device according to claim 1, wherein the alternating current bias voltage is a pulse waveform voltage that deviates from 0 V toward the charging polarity side of the developer. (4) The electrostatic recording device according to claim 1, wherein the frequency of the AC bias voltage is 10 kHz or more.