JPH04194965A - 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-like electrodes (styli) at minute intervals, and selectively applies high voltage to each needle-like electrode according to the image signal, producing electrical discharge directly onto the paper. This process forms an electrostatic latent image. In such a multi-stylus printer, if the distance between the tip of the needle electrode and the paper surface is wide, the discharge electric field will spread and the formed dots will become large, making it difficult to obtain a high-resolution recorded image. For that reason,
A gap material is provided on the surface of the paper, and a needle-shaped electrode is brought into sliding contact with the gap material to ensure a minute gap. However, this multi-stylus printer has the disadvantage that the sword-shaped electrode is thicker because the gap material of the paper comes into sliding contact with the tip of the needle-shaped electrode.

[Purpose of the invention]

The present invention was made in view of the problems of the prior art described above, and an object of the present invention is to provide an electrostatic recording device that can stably form high-resolution recorded images over a long period of time without causing wear on the recording head. purpose.

[Key points of the invention]

In order to achieve the above object, the present invention includes a developer carrying member;
a developer transport means for transporting developer along the surface of the developer carrying member; a plurality of recording electrodes extending along the developer carrying direction on the surface of the developer carrying member; and the recording electrode. A voltage is applied to each of the recording electrodes according to recording information, and the developer conveyed along the surface of the developer carrying member is directed to the opposite electrode. In an electrostatic recording device in which the recording electrode is selectively transferred to the electrode side, the tip of the recording electrode is positioned upstream in the developer transport direction from a portion of the surface of the counter electrode opposite to a position closest to the developer carrying member side. The main point is that the location is

[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 plain paper P, which is detachably attached to the side of the machine. A paper feed roller 1a is disposed 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, two lower conveyance guide plates 2a and 2b made of insulating parts are laid to form a paper transport path. A pair of standby rolls 3 is disposed in this paper feed path, and after temporarily stopping the advance of the paper P fed out by the paper feed roller 1a and adjusting the conveyance posture, the paper P is transferred to the image transfer section T on the downstream side. The image is re-fed in synchronization with the arrival timing of the 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 the arrow. 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 cylinder M. An air suction conveyor belt 7 is stretched horizontally downstream of the separating claw 6, and the paper is separated from the circumferential surface of the cylindrical electrode 5 by the separating claw 6 after the recording image has been transferred. The back surface is sucked and conveyed toward the fixing device 8 provided in front of it. The fixing device 8 includes a heating roll 8a and a pressure roll 8b.
The toner image is thermally fixed when the paper is held between both rolls and conveyed. The paper that has been fixed is transferred from the output port 9 to the output tray 10 with the image side facing down.
It is discharged and loaded on top.

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 a face-down paper discharge state that does not require page alignment, which is preferable for a recording apparatus, can be achieved with two straight paper passing paths.

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

The recorded image forming unit U, as shown in FIG.
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 is used as the 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 for the developer, a one-component developer in which a magnetic carrier and an insulating toner are mixed in a predetermined ratio can also be used.

At the bottom of the development recording tank 12, a horizontal developer circulation path 13 shown in FIG. 3 is formed. In FIG. 3, a pair of parallel longitudinal paths 13a in this horizontal circulation path 13,
A pair of auger rolls 14a and 14b are rotatably installed in 13b. Each auger roll 14a, 14b
As shown in the perspective view of Fig. 4, each shirt) 14a+
, a plurality of spiral blades 14a2, 14 around 14b1
b2 is provided upright, and reverse feed blades 14a3, 14.b2 with opposite helical directions are provided at one end of each. It consists of b3 installed upright. Then, the auger rolls 14a, 14b are arranged in the longitudinal paths 13a, 13b, respectively, so that the respective reverse feed blades 14a3, 14b3 are located on opposite sides. These pair of auger rolls 14a and 14b are driven and rotated in opposite directions to each other and in a direction that conveys the developer toward the reverse feed blades 14a3 and 14b3, as shown by arrows C. 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 l.toner is stirred and circulated in the direction indicated by the broken line arrow 2, and at this time, the magnetic toner can be sufficiently triboelectrified. By changing the material and shape of the auger rolls 14a and 14b, it is possible to triboelectrically charge the developer to a sufficient amount.

A space S is formed in the center of the horizontal circulation path 13 configured as described above, surrounded by walls Sw 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.

On one side of the other auger roll 14b, a developing sleeve 15 for vertically conveying the developer is installed horizontally. The developing sleeve 15 has a magnet roll 1 inside.
6 is rotatably built in, and is arranged opposite to the cylindrical electrode 5 described above. Different magnetic poles are alternately magnetized on the circumferential surface of the magnet roll 16, and by driving and rotating the magnet roll 16 in the counterclockwise direction shown by arrow H, the magnetic toner d is spread along the circumferential surface of the developing sleeve 15. and transport it in the clockwise direction indicated by the dashed arrow.

A doctor blade 12a for controlling the layer thickness of the magnetic toner d to an appropriate thickness is disposed near the circumferential surface of the developing sleeve 15, which serves as a developer conveyance path, and on the upstream side in the developer conveyance direction. Further, a toner scattering prevention plate 12b is disposed on one side of the doctor blade 12a. This toner scattering prevention plate 121] is provided in order to prevent the inconvenience of the developer being transported downstream under the layer thickness regulation by the doctor blade 12a scattering outside the recording image forming unit (U) and staining the image. . In this example, the upper end of the tank wall of the developing and recording tank 12 is bifurcated, and one side is formed as a doctor blade 12a and the other side is formed as a toner scattering prevention plate 12b.

A recording electrode sheet 17 is adhered and laid in an area on the upstream side in the toner transport direction from a position close to the circumferential surface of the cylindrical electrode 5 on the circumferential surface of the developing sleeve 15 (in this example, the circumferential surface on the left side in the figure). be. The recording electrode sheets 17 of this example are made of a flexible printed circuit board (FPC), and as shown in FIG. A plurality of recording electrode lines 17a are arranged in parallel on the base film 171) at a predetermined fine pitch in the cartridge width direction (toner transport path width direction: main scanning direction). The number of recording N pole lines 17a corresponds to the maximum number of data for one main scanning line, which will be described later. In this example, the recording electrode wire 17a consisting of a large number of non-magnetic conductive wires is 40
84.6μm pitch (300DPI) with μm gap maintained.
) is patterned at a density of

Therefore, the recording electrode node 17 configured in two series,
The long plane direction is laid along the circumferential direction of the circumferential surface of the developing sleeve 15. In this case, the tip 17d of the recording electrode sheet 17 (recording electrode line 17a) is moved in the toner transport direction from the position N where the circumferential surfaces of the cylindrical electrode 5 and the developing sleeve 15 are closest to each other, as shown in FIG. 5(a). It is slightly shifted to the J1 flow side compared to the IO-. In this case, if the outer diameter of the cylindrical electrode 5 is 20 mm, the outer diameter of the developing sleeve 15 is 23 mm, and the thickness of the recording electrode wire 17a is 23 μm, it is preferable that the displacement angle of the tip 17d is about III m. In this way, the recording electrode wire 17
By setting the tip 17d of a, a high-resolution recorded image consisting of so-called sharp dots can be formed.

The reason will be explained in detail later.

On the surface of the recording N-pole sheet 17, an insulating coat 17c is adhered except for a predetermined minute region Z from the tip which will become the recording electrode EL. This ensures insulation between each recording electrode wire 17a and prevents wear of the recording electrode wire 17a due to friction with the magnetic toner d. The reason why the insulating coat 17c is not applied to the leading end of the recording electrode sheet 17 is as follows.

Toner recorded images are created by applying a recording voltage according to recording data to the recording electrode line 17a to form an electric field between the recording electrode line 17a and the cylindrical electrode 5, and toner charged by the force of this electric field to the cylindrical electrode 5 side. Formed by selective transfer. However, if the insulating coat 1-170 is coated on the surface of the recording electrode wire 17a to which the recording voltage is applied, not only will the necessary electric field not be efficiently formed (also, unnecessary charges will be accumulated on the insulating coat 17c). This unnecessary charge causes image defects such as background smearing and image disturbance.

Therefore, as shown in FIG. 4, an insulating coat 17c is applied to the leading edge of the recording electrode sheet 17 which is involved in the formation of a toner recorded image and an area Z in the vicinity thereof, and the recording electrode wire 17a is exposed to form the recording electrode. By forming an EL, it is possible to efficiently form the necessary electric field, and at the same time, it is possible to prevent the accumulation of two series of unnecessary charges, and to reliably prevent the occurrence of image defects such as background smearing caused by this. can.

When manufacturing the recording electrode sheet 17 described above, a base film 17b made of a flexible insulating layer coated with copper foil is etched to form a pattern of a large number of recording electrode wires 17a, and an insulating coat 17C is attached to the tip. It suffices to coat the area excluding the partial area Z.

In FIG. 2, on the downstream side of the recording section W where the portion involved in image formation at the leading end of the recording electrode sheet 17 (the recording electrode EL shown in FIG. 5(a)) faces the cylindrical electrode, there is a horizontal circulation as described above. A wall surrounding the central space S of the path 13 stores developer 4i! ! The wall Swl on the side 111i is extended, and its tip is brought into contact with the circumferential surface of the developing sleeve 15. As a result, the magnetic particles d', which are not transferred to the recording area W and remain on the circumferential surface of the developing sleeve 15 and are transported with the rotation of the magnet roll 16, are transferred to the replenishment tank side path 1 of the horizontal circulation path 13.
The magnetic toner d' is scraped onto the developing sleeve 1 without entering the central space S or passing through the horizontal circulation path 13.
5. To prevent the inconvenience of being short-circuited and returned to the upstream side along the circumferential surface. Note that, separately from the peripheral wall of the central space S, the developing sleeve 1
A dedicated flat plate part scraper may be provided for scraping off the residual magnetic toner d' adhering to the magnetic toner 5. In this case, the scraping member may be supported in the vertical direction, its tip abutted on the circumferential surface of the developing sleeve 15, and its other end extended to the bottom of the central space S.

Further, if the scraping member is made of a magnetic material, the magnetic force of the magnet roll 16 can be blocked, and a smoother scraping and return effect can be obtained.

The recording electrode sheet 17 whose tip position is set as described above is
It is laid over about half of the circumferential surface of the developing sleeve 15, pulled out horizontally and then lowered vertically, extending into the central space S of the horizontal circulation path described above. 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 EL in accordance with recording data. Then, as shown in FIG. 4, the recording electrode wires 17a of the recording electrode sheet 17 described above are divided into N pieces and connected to each drive circuit element 18, respectively. In this manner, by housing and installing the other end of the recording electrode sheet 17 on which the drive circuit element 18 is mounted in the central space S, the drive circuit element 18 can be protected from dust such as developer, etc.
The structure of the development recording tank 12 is 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, the outer peripheral surface of the developing sleeve 15 is
A rotating magnetic field is formed that causes the particles of magnetic toner d to rotate, and the magnetic toner d forms spikes on the magnetic roll 16.
It is transported in the direction of the arrow opposite to the direction of rotation. The conveyed magnetic toner d reaches the recording section W after being cut to a predetermined thickness by the doctor blade 12a. At this time, the magnetic l and toner d are mixed with each other and the developing sleeve 15.
It is negatively charged due to friction with the circumferential surface. In the recording section W, recording electrodes EL are arranged in parallel as shown in FIG. Apply. In this case, as shown in FIG. 6, when one bit of recording data is, for example, n As shown in FIG. 5(a), the cylindrical electrode 5 facing the recording electrode EL is powered by a bias power source 5a.
V(7) Since the drum bias voltage Vd is applied,
A potential difference of 150 V is created from the cylindrical electrode 5 toward the recording electrode EL, and a transition electric field is created that moves the negatively charged magnetic toner toward the cylindrical electrode 5, which has a higher potential. As a result, in the recording section W, only the magnetic toner on the recording electrode ELJ to which the on-voltage is applied is selectively transferred to the cylindrical electrode 5.
It metastasizes to the surface and forms a single black dot.

On the other hand, when one bit of recorded data is L'', the recording voltage Vs is switched to the ground potential of 0 (off voltage application state) as shown in FIG. The potential difference seen at the electrode EL is -50V, and a collection electric field is formed in the direction of moving the negative magnetic toner toward the recording electrode EL.As a result, the magnetic toner on the recording electrode EL remains retained and does not transfer. .

As described above, on/off voltages are selectively applied to each recording electrode EL according to the input recording data, and the potential is 1200.
V and ground potential, and a toner recorded image is formed on the surface of the opposing cylindrical electrode 5 in accordance with recorded data. Here, as shown in FIG. 5(a), the tip of the recording electrode EL is placed at a position N where the circumferential surfaces of the cylindrical electrode 5 and the developing sleeve 15 are closest to each other.
Because it is shifted more upstream in the developer transport direction,
A recorded image with higher resolution is formed compared to the case where it is located at the closest position N shown in FIG. 5(b).

When the tip of the recording electrode EL is positioned at the closest position N as shown in FIG. 5(b), a pattern as shown in FIG. A toner image is deposited and formed. Then, as shown in FIG. 6, after the on voltage is applied for a time t (one dot writing period), it is switched to the off voltage. By switching the voltage, the electric field also switches from the transfer electric field to the collection electric field, and as shown by the broken line in FIG. 7(b), the toner at the rear end of the toner image in the direction of movement of the cylindrical electrode is collected toward the recording electrode. be done. In this case, as shown in FIG. 5(b), a portion Nc closest to the developing sleeve 15 side of the circumferential surface of the cylindrical electrode 5 is located directly above the tip of the recording electrode EL. Therefore, the cylindrical electrode 5
With the rotation of the recording electrode EL, the adhered toner unilaterally moves away from the tip of the recording electrode EL, and the collection electric field does not act sufficiently on all the toner moving away. As a result, the toner at the rear end of the formed toner image is not sufficiently collected, resulting in the formation of so-called single black dots with poor sharpness.

On the other hand, in this example, as shown in FIG. 5(a), the tip of the recording electrode EL is slightly shifted upstream from the closest position N in the toner transport direction. For this reason, the recording electrode EL
The rear end portion of the cylindrical electrode 5 is exposed to a greater degree of sunlight than the case shown in FIG. 5(b) from the circumferential surface, and the transfer electric field in that portion becomes weaker, making it difficult to transfer toner from the rear end portion of the recording electrode EL. .

That is, the rear end portion of the recording electrode EL is removed from the region where an electric field capable of transferring toner can be formed. As a result, as shown in FIG. 7(C), the toner image adhesion area becomes narrower than that in FIG. 7(a). When a collecting electric field is applied to this toner image, the amount of toner adhered to the rear end of the toner image to be collected is smaller than in the case of FIG. 7(a), so that toner is sufficiently collected. Moreover, as shown in FIG. 5(a), the cylindrical electrode 5
Since the closest portion Nc on the circumferential surface is located downstream, not directly above the tip of the recording electrode EL, the toner image is located on the downstream side of the recording electrode EL.
After passing directly above the tip, it does not move away unilaterally, but approaches it once and then moves away. Therefore, when switching from the transfer electric field to the collection electric field, the collection electric field acts sufficiently on the toner image area above the tip of the recording electrode EL, and the so-called cutting of the trailing edge of the toner image is improved. That is, the outline of the toner image becomes clear over the entire circumference. As a result, as shown in FIG. 7(d), as shown in FIG. 7(b),
A single black dot that is sharper and sharper than a single black dot is formed, as shown in FIG.

Note that when the tip of the recording electrode is shifted downstream in the developer transport direction from the position closest to the circumferential surface of the cylindrical electrode, the speed at which the toner image moves away from the tip of the recording electrode is faster than in the case shown in FIG. 5(b). As a result, the sharpness of the trailing edge of the toner image becomes noticeably worse. As a result, a single black dot with an irregular outline is formed.

Therefore, as shown in FIG. 5(a), the tip of the recording electrode EL should be moved slightly upstream in the toner transport direction from just below the position Nc closest to the developing sleeve 15 side on the circumferential surface of the cylindrical electrode 5. This makes it possible to stably form a high-resolution recorded image consisting of sharp black dots on the circumferential surface of the cylindrical electrode 5. In this case, the amount of displacement of the tip of the recording electrode EL is preferably 1 degree, assuming that the outer diameter of the cylindrical electrode 5 is 20 mm, the outer diameter of the developing sleeve 15 is 23 mm, and the thickness of the recording electrode is 23 μm. This has been confirmed by the inventors of the present application.

Incidentally, when the image was shifted downstream by 0.5 m, the image quality became extremely distorted, and the image quality did not recover even if other image forming conditions were adjusted.

Further, since the recording electrode EL is exposed without being coated with the insulating coat 17c, unnecessary charges are not accumulated in the recording electrode ELj, . Therefore, scumming caused by unnecessary charges and voltage leakage between the recording electrodes are prevented, and clear toner recorded images with high resolution and high density are stably formed.

In FIG. 1, the toner recorded image formed on the surface of the cylindrical electrode 5 is conveyed to the image transfer section T as the cylindrical electrode 5 rotates in the counterclockwise direction A, as shown in FIG. 3, the image is transferred onto the paper that is re-fed at the correct timing.

Incidentally, in order to adjust the density of the above-mentioned toner recorded image, it is sufficient to change the bias voltage of the bias power supply 5a. In that case, the appropriate adjustment range is about 0 to -50V, and OV
The closer it is to , the higher the image density.

In FIG. 2, the magnetic toner d' remaining in the recording portion W without being transferred to the cylindrical electrode 5 side moves downstream with the rotation of the magnet roll 16, and is scraped off from the surface of the developing sleeve 15 by the scraping wall Swl. The magnetic toner dO falls onto the auger roll 14a and is stirred and mixed with the magnetic toner dO that is replenished from the replenishment port flb.

As the auger roll 14a rotates, residual magnetic toner d' and replenishment magnetic toner d are dropped and returned.

are circulated and conveyed while being mixed and stirred. In Figure 3,
The magnetic toner that is circulated in the two directions indicated by the dashed arrows is conveyed in the vertical direction again by the rotating magnetic field of the magnet roll 16 extending above the magnetic toner when being conveyed along the longitudinal path 13b on the anti-replenishment side.

As described above, the residual magnetic toner d' that was not transferred to the cylindrical electrode 5 side but was transported downstream in the recording section W is scraped onto the horizontal circulation path 13, and is smoothly agitated through this horizontal circulation path 13. YO-21 = Returned to the downstream 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
Since the toner is conveyed while being stirred along the axial direction of the developing sleeve 15 (the width direction of the toner conveying path: the main scanning direction), it 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 section W, making it possible to stably obtain a good recorded image with uniform image density. It becomes possible. Also, magnetic toner d
When the magnetic toner particles are circulated and conveyed through the horizontal circulation path 13 while being stirred, the magnetic toner particles rub against each other, and the magnetic toner is sufficiently triboelectrically charged.

Next, some other embodiments of the present invention are shown in FIGS.
b) to FIG. 10 (aL) This will be explained based on (b).

It should be noted that the same constituent members as in the above embodiment are given the same reference numerals and the explanation thereof will be omitted.

The embodiment shown in FIGS. 8(a) and 8(b) employs a coil conveyance section 19 that generates a traveling wave magnetic field using an excitation coil instead of a magnet roll as the developer conveyance means, and the developer conveyance path is made non-conductive. It is formed in a circular path. The coil conveying member 19 includes a base body 2 formed of a magnetic material with a non-circular cross section.
A large number of grooves 20a are formed in parallel to the width direction on the outer peripheral surface of 0, and a conductive wire is wound between each groove 2Oa to form an excitation coil 21. When the G echo coil 21 is divided into n 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 in the direction of the arrow l along the outer circumferential surface of the coil transfer part shrine 19. do.

Recording electrodes No. 1-17 having the same configuration as in the above embodiment are laid on the outer circumferential surface of this coil conveyance section shrine 19, one end of which is drawn into the base body 20, and the recording electrode drive circuit element 18 is mounted. be. Since the developer conveyance means using the coil conveyance member 19 of this example does not use a rotating member, the durability of the device is improved, and the developer conveyance path can be set freely, which greatly promotes miniaturization of the device. It becomes possible.

Further, the embodiment shown in FIG. 9 (aL(b)) uses a pair of magnet rolls 22, 22 as the developer conveying means, and carries the developer in an oval shape by the continuous IJf' action of the rotating magnetic fields of both. The member 23 is conveyed along the surface of the member 23 in the direction of arrow H. In this case, one end of the recording electrode sheet 17 configured in the same manner as the recording electrode is laid along the surface of the developer carrying member, and the other end is laid down. The recording electrode driving circuit element 18 is mounted inside the surface of the developer carrying member.

In the embodiment shown in FIGS. 10(a) and 10(b), a magnet roll 25 is disposed inside the developing sleeve 24, one end of the recording electrode sheet 26 is laid on the circumferential surface of the developing sleeve 24, and the other end is is drawn out of the developing sleeve 24, and a recording electrode drive circuit element 18 is mounted on the end thereof. In this case, a plurality of openings 26a are provided along the width direction of the recording electrode sheet 26 so as not to block the progress of the developer.

In any of the three embodiments described above, the tip position of each tip of the recording electrode No. 1-17. It is appropriately shifted upstream in the developer transport direction from directly below the nearest position Nc. Further, a step G is formed immediately downstream of the recording electrode tip position. Therefore, in these three embodiments as well, as in the embodiment shown in FIG. 2, it is possible to stably form a recorded image with a high resolution of 1i4'' consisting of a sharp single black dot. ,
By providing the step G, it is possible to prevent the inconvenience that the formed recorded image is disturbed by residual developer, and it becomes possible to obtain a recorded image of higher quality.

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, in the embodiment shown in FIG. 2, negative (-) is used as the toner.
Although a chargeable toner is used, it is also possible to use a positively (1) chargeable toner. In that case, the bias voltage applied to the recording electrode and the counter electrode may be of positive (1) polarity.

〔Effect of the invention〕

As described in detail below, according to the present invention, the developer is transported along the surface of the developer carrying member by the magnetic field transporting means, and a plurality of recording electrodes are arranged on the surface of the developer carrying member with respect to the opposing electrodes. By arranging several recording electrodes in parallel while maintaining a small gap, and by positioning the tip of each recording electrode on the upstream side in the developer transport direction from the position opposite to the position closest to the developer carrying member on the surface of the counter electrode. It is possible to stably form a high-resolution recorded image consisting of so-called sharp dots with a sharp contour. Furthermore, since the electrostatic recording apparatus according to the present invention uses a non-contact recording method, the durability of the recording apparatus is improved, and the above-mentioned high-resolution images can be stably formed over a long period of time.

[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 recorded image forming unit, FIG. 4 is a perspective view showing the recorded image forming unit, and FIGS. 5(a) and 5(b) are respectively shown in FIG. 1
FIG. 6 is a timing chart showing the voltage application operation to the recording section in the recording image forming unit I. Figure 7(a L(b) and Figure 7(c L(
d) are graphs showing the dot forming operation in the comparative example and the above electrostatic recording apparatus, respectively, and FIG. 8 (a'L(b)+
Figure 9 (a L(b)) and Figure 10 (a L(b)
These are side views and perspective views showing other embodiments of the present invention, respectively. 4...Transfer charger 5...Cylindrical electrode 5a...Bias power source (cylindrical electrode side) 11...Developer storage tank 12...Development recording tank 13...Horizontal circulation path 14a, 14b=・Auger roll 15.24...Developing sleeve 1B, 22.25...Magnet)・Roll 17.26
...Recording electrode notebook 17a...Recording electrode wire 17c...Insulating knee 1, 17d...Tip 18...Drive circuit element 19...Coil conveying member 21...Exciting coil EL... Recording electrode G...Step N...Proximity position Nc...Proximity position S on the surface of the counter electrode...Central space U...Recording image forming unit W...Recording unit Patent applicant Casio Computer Co., Ltd. Co., Ltd. Cylindrical electrode circumferential surface arrangement (α) (C) 7th (b) (d) Fig.

Claims (1)

[Claims] (1) a developer carrying member; a developer carrying means for carrying the developer along the surface of the developer carrying member; and a developer carrying means disposed extending along the developer carrying direction on the surface of the developer carrying member It has a plurality of recording electrodes and a counter electrode disposed with a required gap from the recording electrodes, and a voltage is applied to each of the recording electrodes according to recorded information, and a voltage is applied to each of the recording electrodes along the surface of the developer carrying member. In an electrostatic recording device that selectively transfers the developer being conveyed to the counter electrode side, the tip of the recording electrode is developed from a portion opposite to a position closest to the developer carrying member on the surface of the counter electrode. An electrostatic recording device characterized in that it is located on the upstream side with respect to the agent transport direction.