JPH04156351A - electrostatic recording device - 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 [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 electrodes (stylus) at evenly spaced intervals in the main scanning direction, and selectively applies voltage to each needle-shaped electrode according to the recording signal. Second, 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 the paper -1- can easily and stably retain the charge. However, such special paper is not preferred as paper for office use because it is difficult to write on with a pencil or pen, and its quality deteriorates depending on environmental conditions such as humidity, so there are problems with storage stability.

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 an electrostatic recording method that can use plain paper and accurately ensure a minute distance between the image medium and the tip of the recording electrode, an L/ner image is formed on a drum-shaped intermediate recording medium7. A method is used in which the toner image is transferred onto paper. However, in this method, scumming is likely to occur in the developing process in which a toner image is obtained by supplying a developer to the surface of the intermediate recording medium. Furthermore, there is a tendency for devices to become larger due to the use of intermediate recording media.

[Purpose of the invention]

The present invention has been developed in view of the problems of the prior art described in section 2. It allows the use of plain paper, promotes miniaturization, and provides clear recorded images with high resolution and no background smear for a long period of time. An object of the present invention is to provide an electrostatic recording device that can be stably formed over a long period of time.

[Key points of the invention]

In order to achieve the above object, the present invention includes a non-magnetic cylindrical body containing a rotatably supported magnet roll, and a plurality of cylindrical bodies arranged in parallel along the axial direction of the cylindrical body on the circumferential surface of the cylindrical body. a recording electrode, a connection means disposed on the surface of the cylindrical body for connecting each of the recording electrodes and a signal generation means for generating a recording voltage according to input recording information; and a connection means disposed substantially below the cylindrical body; a plurality of conveying means for circulating the developer in the axial direction of the cylindrical body; a counter electrode disposed with a predetermined gap with respect to the recording electrode; and applying the recording voltage to the recording electrode. In an electrostatic recording device in which developer, which is conveyed in a substantially vertical direction from the conveying means to the cylindrical body by rotation of the magnet roll, is selectively transferred to the counter electrode side, an alternating current bias voltage is applied to the counter electrode. The key point is to apply .

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 8.

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 tray (1) loaded with plain paper P, which is detachably attached to the side of the machine. A paper feed roller 1a is arranged at one end of the distal end 91 of the inserted paper feed cassette 1 so as to be rotatable in the direction of the arrow.

On the i) i+ side of the paper feed roller 1a, there is a [-
1. Lower conveyance guide plates 2a and 2b are laid down to form a paper transport path. A pair of standby rolls 3 is disposed in the paper 1ω path, and after temporarily stopping the advance of the paper P fed by the paper feed roller 1a and adjusting the conveyance posture, the paper P is transferred to the image transfer section on the downstream side. It is re-fed to T 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 opposite to a cylindrical electrode 5 which also serves as an image carrier.

In this example, the cylindrical electrode 5 is driven and rotated in the counterclockwise direction indicated by arrow A. Since this cylindrical electrode 5 uses a developer with negative (-) triboelectric charging characteristics as described later, an AC bias voltage obtained by superimposing an AC voltage on a negative DC voltage is applied to the cylindrical electrode 5. An AC bias power source 5a capable of output is connected. In this case, the frequency of the AC bias voltage is 10 kHz or more. In this way, by applying a high frequency alternating current bias voltage to the cylindrical electrode, it is possible to obtain a recorded image free from background smear and with sufficient image density. The reason for this will be explained in detail in the explanation of the recording operation later.

On the opposite circumferential surface of the cylindrical electrode 5, a recording image forming unit U, which will be described later, is arranged to face the cylindrical electrode 5. 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 transferred onto the paper that is being fed again. . The configuration of the recorded image forming unit U will be explained in detail later.

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. Then, on the downstream side of the separation claw 6, an air succilon type conveyor belt 7 is horizontally stretched, 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 conveyance path from paper feeding to paper ejection is formed in a substantially straight shape, so the paper feeding operation is generally smooth and the image quality is reduced.) This method is less likely to cause sheet feeding failures such as paper jams or paper jams.Furthermore, it has the advantage that the above-mentioned straight sheet feeding path can achieve a face-down sheet discharge state that does not require page alignment, which is preferable for a recording apparatus.

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

As shown in FIG. 2, the recording image forming unit) U is approximately
a development recording tank 12 equipped with a recording means and a developer conveying means;
The developer storage tank 11 stores developer for replenishment.

In the developer storage tank 11, a stirring blade 11a is rotatably arranged. In this example, an insulating magnetic toner d is used as a developer, which is a one-component developer containing at least an insulating resin, a magnetic fine powder, and colorant particles, and has a negative (-) friction charge polarity. As the developer, a two-component developer in which a magnetic carrier and an insulating toner are mixed in a predetermined ratio can also be used. Further, the friction charge polarity is not limited to negative (-), but it is also possible to use a developer having positive (+) friction charge polarity.

At the bottom of the development recording tank 12, a horizontal developer circulation path 13 as shown in FIG. 3 is formed. This horizontal circulation path 1
A pair of parallel longitudinal paths 13 a, 13 in 3
In b, auger rolls 14a, 14b are respectively rotatably installed. Each auger roll 14a, 14b is
As shown in the perspective view of FIG. 4, each shaft 14a+, 14
A plurality of spiral blades 14 a2, 14 b2 are erected on the circumferential surface of the bl, and a reverse feed blade 1 whose spiral direction is opposite is provided at one end of each.
It consists of 4a3.14b3 installed upright. The auger rolls 14a, 14b are installed in parallel with each other, with the reverse feed blades 14a3, 14b3 located on opposite sides. As shown in FIG. 3, these pair of auger rolls 14a and 14b are driven and rotated in opposite directions indicated by arrows C and in a direction that conveys the developer toward the reverse feed blades 14a3 and 14b3. As a result, at a portion of each corner where the reverse feed blades 14a3 and 14b3 are provided, conveying forces in opposite directions collide with each other, and the magnetic toner is pushed out in the right angle direction and flows toward the other longitudinal path. In this manner, in this example, the magnetic toner is stirred and circulated in the direction shown by the broken line arrow 2, and at this time, the magnetic toner can be sufficiently triboelectrically charged. In addition, Augarol 14a,
By changing the material and shape of the developer 14b, it is possible to sufficiently triboelectrically charge the developer with the necessary amount of charge.

A central space S is formed in the center of the horizontal circulation path 13 configured as described above, surrounded by a wall Sv to prevent the circulating developer from entering. As shown in FIG. 2, a replenishment port 11b for replenishing magnetic toner dO is provided above the auger roll 14a near the developer storage tank 11 along the axial direction of the auger roll 14a. be.

Above the other auger roll 14b, a developing sleeve 15 for conveying the developer in the vertical direction is installed extending parallel to the auger roll 14b. The developing sleeve 15 has a magnet roll 16 rotatably built therein, and is arranged to face the cylindrical electrode 5 described above. Different magnetic poles are alternately magnetized on the circumferential surface of the magnet roll 16, and the magnet roll 16 is driven and rotated in the counterclockwise direction shown by the arrow H to spread the magnetic toner d along the circumferential surface of the developing sleeve 15 along the broken line. Convey in the clockwise direction shown by the arrow.

A doctor blade 12a is disposed on the first flow side of the circumferential surface of the developing sleeve 15, which serves as a developer conveyance path, with respect to the developer conveyance direction, to regulate the layer thickness of the conveyed developer to an appropriate thickness. It is. On the downstream side of the doctor blade 12a, the position W where the circumferential surface of the developing sleeve 15 is closest to the circumferential surface of the cylindrical electrode 5 with a small gap therebetween is the recording position, and as described later,
Magnetism being conveyed here! - The toner d is selectively transferred to the circumferential surface of the cylindrical electrode 5 according to the recorded information to form a toner recorded image. In order to transfer the toner efficiently, it is desirable that the minute gap at the recording position W be set to 1001 m or less.

On the downstream side of the recording position W, there is a wall S on the developer storage layer 11 side among the walls surrounding the central space S of the horizontal circulation path described above.
wl is extended and its tip is brought into contact with the circumferential surface of the developing sleeve 15. As a result, the magnetic toner d' that was not transferred at the recording position W and remained on the circumferential surface of the developing sleeve 15 and was transported by the rotation of the magnet roll 16 is scraped onto the longitudinal path 13a on the supply tank side of the horizontal circulation path, and the magnetic toner d' 1
- Prevents the inconvenience of S-d' entering the central space S or returning directly to the first stream side along the circumferential surface of the developing sleeve 15 through the horizontal circulation path. Note that a dedicated scraper for scraping off the residual magnetic toner d' adhering to the developing sleeve 15 may be provided separately from the peripheral wall of the central space r:4js. In this case, the scraper is supported vertically,
The tip may be brought into contact with the circumferential surface of the developing sleeve 15, and the other end may be extended to the bottom of the central space S. Also, make the scraper magnetic 4. If formed with JH, magnetic roll 16
can block the magnetic force, resulting in a smoother scraping and return effect.

A recording electrode 1-17 is placed on the circumferential surface of the developing sleeve 15 in an area on the "1st stream side" in the toner transport direction from the recording position W. The recording electrode sheet 17 of this example is made of a flexible printed circuit board (FPC), and as shown in FIG. They are formed to extend in parallel in the sheet width direction (toner conveyance path width direction: main scanning direction) at a predetermined fine pitch. Recording signal line 17
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 17a are
84.6μm pitch (300DPI) with a gap of m
The pattern is formed with a density of .

In FIG. 2, recording electrode sheets 17 configured in a double series are laid over about half of the circumferential surface of the developing sleeve 15, pulled out horizontally, and then lowered directly to the shore to complete the horizontal circulation described above. It extends into the central space S of the route. A plurality of drive circuit elements 18 are mounted on the vertically extending portion of the recording electrode sheet 17 to apply a recording voltage to each recording electrode line according to input recording information. As shown in FIG. 4, an appropriate number of recording electrode lines 17a are connected to each drive circuit element 18. In this way, recording electrode sheet 1
By accommodating and installing the drive circuit elements 18 in the central space S, the drive circuit elements 18 can be protected from dust such as developer, and the structure inside the development recording tank 12 can be made extremely compact.

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

In FIG. 2, when the magnet roll 16 is driven and rotated in the direction of the small arrow, a rotating magnetic field is formed on the circumferential surface of the developing sleeve 15 that causes the particles of magnetic toner d to rotate, and the magnetic toner d forms spikes (toner chains). is conveyed in the direction indicated by the broken line arrow, which is opposite to the rotational direction of the magnet roll 1G. The conveyed magnetic toner d reaches the recording position W after being cut to a predetermined thickness by the doctor blade 12a. At this time, the magnetic toner d used in this example is
Friction between the toners and the peripheral surface of the developing sleeve 15 sufficiently charges the toners to a negative polarity.

At the recording position W, each recording electrode line and the surface of the cylindrical electrode 5 face each other with a microgap between them, and an electric field is formed in the microgap according to the recorded information, and this electric field causes the L/ner transported The magnetic toner d at the tip of the chain that contacts the surface of the cylindrical electrode 5 is selectively adhered to the surface of the cylindrical electrode 5 to form a toner recorded image. In this case, the minute gap at the recording position W can be accurately and stably secured without providing a gap material or the like, so a high-resolution recorded image can be stably obtained in a non-contact manner. The high resolution toner recorded image is formed as follows.

FIG. 5 is a timing chart showing the relationship between the recording voltage Vs applied to the recording electrode line and the AC bias voltage Vd applied to the cylindrical electrode. To explain with reference to the same figure and FIG. 2, since the charging polarity of the magnetic toner d used in this example is negative (-), the cylindrical electrode 5 is supplied with OV and -50V by the AC bias power supply 5a. The peak frequency is 1
0. An AC bias voltage Vd biased toward the negative polarity side of 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, the drive circuit element 18 applies a recording voltage Vs that changes between -200 V (on voltage) and OV (off voltage) in accordance with the input recording data.
Apply. In this case, when the 1-bit recording information input to the drive circuit element 18 is lHl'', an on-voltage of 1200 V is applied to the corresponding recording electrode line. +200V towards
A potential difference of 50V is created. Since the negatively charged magnetic toner d is attracted toward the higher potential, at the recording position W where the interval is the narrowest and the electric field is maximum, -2
Only the magnetic toner d of the toner chain moving on the recording electrode line to which a voltage of 00V is applied selectively adheres to the surface of the cylindrical electrode 5, forming a black dot.

When one bit of recording information is II L II, an off voltage of Ov in this example is applied to the recording electrode line. As a result, the potential difference seen from the cylindrical electrode 5 to its corresponding recording electrode line is O
V~-50V, and the negative magnetic toner d is drawn toward the recording electrode line having a higher potential, but does not adhere to the surface of the cylindrical electrode 5, and moves downstream while being held as a toner chain.

By applying an AC bias voltage to the cylindrical electrode 5 as described above, compared to the conventional case in which a DC bias voltage Vd' of -50V is applied to the cylindrical electrode 5 as shown in FIG.
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 through the recording position W, the magnetic toner at its tip is in contact with the surface of the cylindrical electrode 5. When the magnetic toner comes into contact with the surface of the cylindrical electrode 5, physical adhesion forces such as so-called mirror image force and Van der Waals force act therebetween, and the magnetic toner tends to adhere to the surface of the cylindrical electrode 5. When the recording information is "L" and the magnetic toner adheres to the surface of the cylindrical electrode 5 due to the above-mentioned mirror image force, an image is generated.
Second, it appears as dirt on the ground. In order to prevent the occurrence of this scumming, a bias voltage is usually applied to the cylindrical electrode 5.
A collection electric field force is applied to detach the attached magnetic toner from the surface of the cylindrical electrode 5 and collect it toward the recording electrode line.

However, the constant DC bias voltage Vd' shown in FIG.
According to the conventional method of applying , when the magnetic toner is highly charged, a physical adhesion force greater than the recovery electric field force due to the DC bias voltage Vd' acts, and 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 the mirror image force that acts on the magnetic toner in the i-ner cloud state is
It is weaker than when the magnetic toner is merely in contact with the surface of the circularly charged electrode 5. Therefore, even if highly charged magnetic toner is transported to the recording position W, since it forms a toner cloud, the physical adhesion force that acts on it is small, and when the input recording information is 11 L'', it will not reach the recording electrode line. When an off-voltage of O is applied, the intermittently acting recovery electric field force and the magnetic force of the magnet roll 16 cause the recording electrode line to be pulled toward the recording electrode line τ] and move downstream, preventing background smearing. .

By the way, according to an experiment conducted by the inventors of the present application, when the on-voltage of the recording voltage Vs was set to -200V, the bias voltage Vd was set to O and -1, and the AC bias voltage with a peak of OOV and a frequency of 500H2, No effect on preventing the occurrence of scumming was observed. However, when the frequency of the applied AC bias voltage Vd is increased to 10 kHz, the background smudge prevention effect begins to appear, and
It has been confirmed that the maximum scumming prevention effect can be obtained with This is 17 of two consecutive 1,0 kHz waves.
Two cycles of 50 μsec is the time required for the magnetic toner to move between the electrodes, and for frequencies higher than that, the magnetic toner cannot move between the electrodes and vibrates locally near the surface of the cylindrical electrode 5.
This is because the toner is in a 1ξ state.

If the recorded information is “I-B”, the on-voltage (
-200V) is applied, so as mentioned above, negative (
-) A strong electric field is formed that attracts the magnetic toner toward the cylindrical electrode 5 side. Therefore, even if the magnetic toner forms a toner cloud, it can be reliably attached to the surface of the cylindrical electrode 5 due to its strong electric field force, and sufficient image density can be obtained.

Note that as the AC bias voltage applied to the cylindrical electrode 5, O
A pulse waveform voltage biased toward the charging polarity of the developer from (2) may be used. In this case as well, it is possible to form a toner cloud and prevent the occurrence of background smearing, as in the case where a DC bias voltage and an AC voltage are superimposed.

In FIG. 1, the toner recorded image formed on the circumferential surface of the cylindrical electrode 5 at the recording position W is conveyed to the image transfer section T as the cylindrical electrode 5 rotates in the counterclockwise 1i-1 rotation direction A, where it is transferred to a standby roll. The image is transferred onto the paper that is re-fed at the correct timing using pair 3.

The residual magnetic toner d' that has not been transferred to the cylindrical electrode 5 side at the recording position W but has been transported downstream is scraped off from the surface of the developing sleeve 15 by the scraping wall Swl, and is deposited on the replenishing side auger roll 14a of the horizontal circulation path. Fall. Auger roll 14a
As the residual magnetic toner d' is rotated, the residual magnetic toner d' dropped and returned and the magnetic l supplied from the replenishment port 111 of the developer storage layer 11 are mixed.
- The lee-do is mixed and stirred, and as shown in FIG. 3, it is circulated and transported in the horizontal circulation path 13 in the two directions indicated by the broken line arrows by the cooperation with the other auger roll 14b. In FIG. 2, when the magnetic toner d that is being circulated is conveyed along the longitudinal path 131) on the anti-replenishment side, it is again conveyed in the vertical direction by the rotating magnetic field of the magnet roll 16 extending in one direction. Ru.

As shown in the figure below, the residual magnetic toner d' that has not been transferred to the cylindrical electrode 5 side at the recording position W but has been transported downstream is smoothly mixed with the replenishing magnetic l-toner dO through the horizontal circulation path. The toner is returned to the upstream side and used again to form a toner recorded image. In this case, the magnetic toner d before being conveyed in the vertical direction is conveyed while being stirred along the axial direction of the developing sleeve 15 (width direction of the toner vertical conveyance path: main scanning direction) in the anti-replenishment side longitudinal path 131). Therefore, the developing sleeve 15 is always uniformly supplied over the entire circumferential surface of the developing sleeve 15 in the width direction. Therefore, the magnetic toner d is always uniformly supported on the circumferential surface of the developing sleeve 15 over the entire width direction and is conveyed to the recording position W, making it possible to stably obtain a good recorded image with uniform image density. It becomes possible. In addition, when the magnetic toner d is circulated and conveyed while being stirred in the horizontal circulation path, the magnetic toner d is
The toner particles rub against each other, and the magnetic toner is sufficiently triboelectrically charged.

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

For example, as shown in FIG. 7, a coil roll 19 that utilizes a traveling wave magnetic field generated by an excitation coil may be employed as a means for conveying the developer in the vertical direction. coil roll 19
A large number of grooves 20a are formed in parallel to the width direction on the outer circumferential surface of a base body 20 made of a magnetic material and having a cross section that is an omitted circle, excluding a part of the circle.
The excitation coil 21 is formed by winding a conducting wire between each of the grooves 2Oa. This excitation coil 2
When the coil roll 19 is divided into n appropriate groups and an alternating current with a phase shift of π/n is applied to each group, a traveling wave magnetic field is generated that travels along the circumferential surface of the coil roll 19 in the direction indicated by the broken line arrow. . A recording electrode sheet 2 constructed similarly to the recording electrode sheet 17 shown in FIG.
2 is installed. Also, the recording position W (recording electrode sheet 2
Residual magnetic toner d' is placed on the flat surface downstream of the tip
A scraping plate 23 is provided.

Even with the coil rolls 19 configured in two series, the magnetic toner can be conveyed vertically smoothly in the same manner as in the above-described embodiment, and it is possible to stably obtain clear recorded images with high resolution. . In addition, in the case of the coil roll 19 of this example, since the rotating part side is not used, the durability of the device is improved, and the developer conveyance path can be freely set, which greatly promotes miniaturization of the device. It becomes possible.

Further, as shown in FIG. 8, the developer circulating means may be constructed using a spring belt 24. In this case, pulleys IJ25 and IJ25 are respectively disposed at both ends of the developer circulation path 13 having the same configuration as the embodiment shown in FIG.
The spring belt 24 is wound between the 25 and 25. Boo IJ25,2
5 is driven and rotated in the direction of the arrow, and the spring belt 24 is rotated in the direction of the arrow N, the magnetic toner also follows and flows in the same direction. Note that instead of the spring belt 24, a normal band belt may be wound around. The belt-type circulation conveyance means of this example can be configured to be smaller than the auger roll type described above, and is extremely advantageous for downsizing the apparatus.

〔Effect of the invention〕

As described above in detail, according to the present invention, the developer is conveyed vertically upward from the bottom circulation path using magnetic force, and then dropped back to the circulation path to be recycled. By arranging a plurality of recording electrodes in parallel and arranging opposing electrodes with a small gap between them, and applying an AC bias voltage to the opposing electrodes, it is possible to stably and accurately secure a small gap between the opposing electrodes, and also to The agent can be suspended in a cloud. As a result, it is possible to ensure sufficient image density without background smearing and to stably form a high-resolution recorded image.

Further, by arranging the signal generating means for the recording electrodes in the central space of the bottom circulation path, the structure of the developing and recording section that performs development and recording at the same time can be greatly simplified. Therefore, it is possible to manufacture an electrostatic recording device that is small and inexpensive and can stably form high-resolution, good recorded images on plain paper.

Furthermore, since the developer can be uniformly supplied in the width direction of the vertical conveyance path while being stirred and conveyed along the bottom circulation path, variations in image density due to unevenness of the developer can be prevented.

In addition, since it is a non-contact recording method, the durability of the electrostatic recording device is improved, and it can stably produce good images with no background smear, high resolution, sufficient image density, and no variations over a long period of time. can be formed.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the overall configuration of an electrostatic recording device as an embodiment of the present invention, FIG. 2 is a sectional view showing a recorded image forming unit and its peripheral configuration in the electrostatic recording device, and FIG. 3 is a plan sectional view showing the horizontal circulation path of the recording image forming unit described in 1. FIG. 4 is a perspective view showing the recording image forming unit, and FIG. 5 is a timing diagram showing the voltage control operation in the electrostatic recording device. 6 is a timing chart showing a comparative example for the voltage control operation described in 1. FIGS. 7 and 8 are schematic sectional views showing other embodiments of the present invention, respectively. 4...Transfer charger 5...Cylindrical electrode 5a...AC bias power supply 11...Developer storage tank 12...Development recording section 13...Horizontal circulation path 14, a, 14 b-...・Augarol 15...
・Developing sleeve 16... Magnet roll 17.22... Recording electrode sheet 17a... Recording electrode wire 18... Drive circuit element 19... Coil roll 21... Excitation coil 24... Spring belt S ... Central space U ... Recording image forming unit W ... Recording position Patent applicant Casio Computer Co., Ltd. 271

Claims (6)

[Claims] (1) A non-magnetic cylindrical body containing a rotatably supported magnet roll, a plurality of recording electrodes arranged in parallel along the axial direction of the cylindrical body on the circumferential surface of the cylindrical body, and each of the recording electrodes. and a signal generating means for generating a recording voltage according to input recording information, the connecting means being disposed on the surface of the cylindrical body, and the connecting means being disposed substantially below the cylindrical body, and a connecting means disposed substantially below the cylindrical body, and a connecting means disposed on the surface of the cylindrical body, and a connecting means disposed substantially below the cylindrical body, and a signal generating means for generating a recording voltage according to input recording information. a plurality of conveyance means for circular conveyance in the axial direction; a counter electrode disposed with a predetermined gap between the recording electrodes; and by applying the recording voltage to the recording electrodes, the rotation of the magnetic rolls An electrostatic recording device that selectively transfers the developer conveyed from the conveyance means onto the cylindrical body in a substantially vertical direction to the counter electrode side, characterized in that an alternating current bias voltage is applied to the counter electrode. Electrostatic recording device. (2) The electrostatic recording device according to claim 1, wherein the signal generating means is provided in a space between the cylindrical body and the conveying means. (3) The electrostatic recording device according to claim 1, wherein the conveying means has a stirring function. (4) The electrostatic recording device according to claim 1, further comprising a scraper that comes into sliding contact with the cylindrical body and peels off the developer conveyed onto the cylindrical body. (5) The electrostatic recording device according to claim 4, wherein the scraper is made of a magnetic material. (6) The electrostatic recording device according to claim 1, further comprising a developer replenishing means for replenishing developer downstream of the opposing portion of the opposing electrode and the recording electrode.