JPH0427969A - Electrostatic recorder - Google Patents

Abstract

PURPOSE:To stably form a high-resolution recorded image by forming a cylindrical electrode by laminating a surface layer consisting of a substance whose volume resistivity value is changed in accordance with the intensity of electric field on a conductive substrate. CONSTITUTION:The cylindrical electrode 5 is formed in two-layer structure obtained by laminating the surface layer on a conductive sleeve. The surface layer consists of the substance having characteristic that the volume electric resistivity value becomes smaller as the intensity of acting electric field gets higher. By arranging the electrode 5 so as to be opposed to a recording electrode 20, the line of electric force of the electric field by which developer (d) is transferred at an electrode opposing part is focused on the center part of the electrode. Thus, the developing electric field having the small radiation angle of the line of electric force and sharp intensity distribution is formed and the high-resolution image is stably formed with dots having proper size and distinct contour at the electrode opposing part where an enough opposing gap is secured.

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 layer is provided on the surface of the paper, and the gap layer and the needle-shaped electrode are brought into sliding contact to ensure a minute gap.

However, this multi-stylus printer has the disadvantage that the needle-like electrodes are worn out because the paper is always in sliding contact with the tips of the needle-like electrodes.

[Purpose of the invention]

The present invention has been 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 without causing wear on the recording head. .

[Key points of the invention]

In order to achieve the above object, the present invention disposes an excitation coil along the back surface of a developer transport body made of a non-magnetic material fixedly laid so that the surface becomes a developer transport path, and a developer transporting means for transporting the developer by applying current of multiple phases with different values to form a magnetic field that waves along the surface of the developer transporting member; and a plurality of recording electrodes on the surface of the developer transporting member; a recording means arranged in parallel in a direction perpendicular to the developer conveyance direction, and comprising a drive circuit installed inside the developer conveyance means for outputting a recording voltage to each of the recording electrodes according to input recording information; cylindrical electrodes are arranged opposite to each other 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, the developer is transported to the electrode facing part by the developer conveying means. In an electrostatic recording device that selectively transfers the developer being conveyed to the cylindrical electrode side, the cylindrical electrode is coated with a surface layer made of a material whose volume resistivity changes depending on the strength of an electric field on a conductive substrate. The main point is that it is formed by laminating layers.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 14.

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 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, there is formed a paper transport path defined by upper and lower conveyance guide plates 2a and 2b made of insulating members. 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.

The cylindrical electrode 5 has a two-layer structure in which a surface layer 5b is laminated on a conductive sleeve 5a. Here, the surface layer 5b is made of a material having a characteristic that its volume electric resistance value decreases as the strength of the applied electric field increases, as shown in FIG.

Typical materials with such characteristics include dielectric materials, among which polyamide film, anodized aluminum, and the like are suitable as materials for the cylindrical electrode surface layer 5b. Incidentally, a semiconductor substance can also be used as the material for the surface layer 5b.

Since the cylindrical electrode 5 configured as described above uses a developer having negative friction charge polarity as described later in this example, -
A bias power supply 5c capable of applying a bias voltage of 50V is connected. Then, the cylindrical electrode 5 is driven and rotated in the counterclockwise direction indicated by the arrow a.

On the circumferential surface on the opposite side of the cylindrical electrode 50, a recording image forming unit (U), which will be described later, is arranged to face the cylindrical electrode 50. 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. . In this case, since the surface layer 5b made of a dielectric material is provided on the cylindrical electrode 5 as described above, the recording image forming unit U
This makes it possible to form high-resolution toner recorded images. The configuration of the recorded image forming unit (U) and the recorded image forming operation 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. On the downstream side of the separation claw 6, an air succinct conveyor belt 7 is stretched horizontally, 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 inserted into the recording portion W through the opening 11a opened toward the circumferential surface of the cylindrical electrode 5 described above.
It is arranged in such a way that it faces the In this example, a high-resistance magnetic toner d, which is a one-component developer containing at least an insulating resin, a magnetic fine powder, and colorant particles and has negative (-) triboelectric charging characteristics, is used as the developer. 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.

FIG. 2 is a schematic cross-sectional view showing the recording unit U and its peripheral members. The recording unit U of this example has a columnar body with an oval cross section and extending in the direction perpendicular to the plane of the paper, and has a base 14 made of a high magnetic permeability material such as iron, nickel, permalloy, etc.
An outer covering member IS made of a non-magnetic material and whose surface serves as a conveyance path for the magnetic toner d is coated on a region excluding a part of the outer circumferential surface of the magnetic toner d. The peripheral surface of the base body 14 covered with the outer cover member 15 includes
A large number of concave grooves 14a having a V-shaped cross section are formed parallel to each other at equal intervals along the longitudinal axis direction of the base body (direction perpendicular to the plane of the paper). Although FIG. 2 only shows a total of 12 concave grooves 14a, in reality there are more concave grooves 14 than that.
A is 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 covering member 15.

A conducting wire lea is buried and laid in each circuit groove 14a,
A coil portion 16 as a part of the excitation coil is formed respectively. As shown in FIG. 3(a), this coil portion 16 is
In this example, it is divided into two groups, A and H, and each group's coil portion 16A,
16B are arranged every other piece. In this case, Figure 3 (
As shown in b), a pair of coil parts IE3.16 adjacent to each other with one coil part 16 in the other group in the same group (for example, consecutive odd-numbered and even-numbered coil parts with the coil part 16B1 16A1 and 1f3A2) are the same conductor I
It is formed by winding E3a many times in a predetermined direction across every other pair of concave grooves 14a, 14a. Therefore,
A pair of coil parts 16 that are adjacent to each other every other time in the same group.
The running directions of the 18 conductive wires lea (based on the winding direction of the coil) are opposite to each other.

In addition, when the coil part 16 is divided into m groups of 3 or more, the coil parts of each group are arranged every (m-1) pieces, and the conductor 1
A pair of concave grooves 14a, 14a every (m-1) 6a
to form a pair of coil parts of the same set.

As shown in FIG. 4, two types (two phases) of alternating current AllB1A are applied to the A string coil section 4A and the B silk coil section 4B constructed as described above, with the phase shifted by π/2. = I sin (ωt) ・・・・・・
・・・・・・ (1) fB=Isln(ωt+π/2)
= (2) are energized, respectively. Incidentally, the coil part 16
A.

If the coils are divided into m groups of B, . . . , M, each coil group has m types (m
The alternating currents of the sets) are applied in the order of arrangement.

Coil part IEiA and 16A i A=Is+n(ω t) Coil part 16B and IE3B i in: I sin ((Ll t + π/m) Coil part 16M and IC3M 1 M:=Isln(ω t+(m-1) r/m) However, ■ = wave height value (maximum value) ω = 2πf, f: frequency t: time By applying an alternating current to each coil portion 16 as described above, the distance between each concave groove 14a in the base body 14 is Each partition portion 14b is excited by a magnetic field corresponding to the applied current as shown in 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.T is the period of the alternating current to be applied.In this example, As mentioned above, the running directions of the conductors in the odd-numbered and even-numbered coil sections 16 (for example, 16Al and 1612) in each set are reversed.Therefore, alternating currents of the same phase can be passed through the coil sections 16 of the same class. For example, the directions of the magnetic fields excited by the odd-numbered and even-numbered fill portions 16 are opposite to each other.As a result, the distribution curve of the magnetic field formed on the surface of the sleeve 2 also becomes as shown in FIG. A waveform corresponding to an alternating current is drawn. Since this waveform magnetic field changes with a period T like the 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 wave-shaped magnetic field formed on the surface of the sleeve 2 by the entire fill portion 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.

Incidentally, the method of winding the conducting wire to lay and form the excitation coil that generates the traveling wave magnetic field as described above around the circumferential surface of the base body 14 is not limited to the above-mentioned method, but as shown in FIG. One coil 16' may be formed by winding the conducting wire lea around six protrusions 14'a provided on the circumferential surface. Moreover, as shown in FIG. 7, no unevenness is formed on the peripheral surface of the base, and the conductor
The coil may be formed by extending and laying the coil a while folding it back in a direction perpendicular to the circumferential direction. In this case, the single conductive wire portion 16# from being folded back at one end to being folded back at the other end corresponds to the coil portion 16 or coil 16' of the above embodiment. Furthermore, instead of the above-mentioned normal alternating current, an alternating current based on pulse width modulation may be applied.

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. Both outer covering members 15A are used to form a flat toner conveyance path.

A bridge member 17 is installed at the joint 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 shoe.
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. The position where the circumferential surface of the jacket member 15A is closest to the circumferential surface of the cylindrical electrode 5 with a small gap on the downstream side of the doctor blade 18 is the recording section W, where the magnetic toner d is applied to the cylindrical electrode 5 according to input recording data. The toner is selectively transferred to the surface to form a toner recorded image. On the downstream side of the recording section W, a scraping plate 19 is disposed with its tip pressed against the surface of the jacket member 15A. By this scraping 19, the residual magnetic toner d' that has been conveyed without being used in the recording section W is scraped off onto the stirring roll 12 (see FIG. 1).

As shown in FIG. 8, a recording electrode sheet 20 is placed on the circumferential surface of the outer cover member 15A in an area upstream from the recording section W to the opening in the toner transport direction. . The recording electrode sheet 20 of this example is made of a flexible printed circuit board (FPC), and has a plurality of recording electrode lines 20a extending parallel to each other in the sheet longitudinal direction in the sheet width direction (toner conveyance path width direction). They are formed to extend in parallel on the base film 20b at a predetermined fine pitch. The number of recording signal lines 20a is
This corresponds to the maximum number of data for one main scanning line, which will be described later. When manufacturing the FPC recording electrode sheet 20 of this example, a base film 20b made of a flexible insulating material covered with copper foil is etched, and a large number of recording electrode wires 2 are etched.
0a with a pitch of 86μm (300μm, keeping a gap of 40μm)
The pattern is formed at a density of DPI). Although not shown, an insulating film is coated on the surface of the recording electrode wire 20 to ensure insulation between the recording electrode wires 2Oa.

As shown in FIG. 2, the recording electrode sheet 20 described above is submerged below the bridge member 17 and
It passes through the joint surface of B and extends to the internal space S. A plurality of drive circuit elements 21 are arranged within the internal space S to drive the recording electrode lines 20a according to recording data. The recording electrode lines 20a of the recording electrode sheet 20 described above are divided into N pieces and connected to these drive circuit elements 21, respectively. From each drive circuit element 21, an input wiring circuit 22
is pulled out from the other joint surface of the divided bases 14A and 14B to the outside of the recording unit (Ull). The input wiring circuit 22 is
It is connected to a recording control section (not shown).

Here, regarding the configuration and operation of the drive circuit element 21, the ninth
This will be explained based on the block diagram shown in the figure.

The drive circuit element 21 consists of a shift register 21a, a data latch 21b, an AND circuit section 21C, a driver section 21d for driving recording electrode lines, and a pull-down resistor section 21e, and these are sequentially connected to the N recordings assigned to each drive circuit element 21. They are connected via the same number of signal lines as the electrode lines 20a. Assuming that the maximum paper that can be used with the recording device of this example is A4 size, the recording density is 300D as described above.
Since it is PI, the maximum data for one line in the main scanning direction (the width direction of the toner transport path in the recording section W: the direction in which the recording electrode lines 20a are arranged in parallel) is approximately 2400 bits.

The shift register 21a is connected to the recording data and data clock signal input lines 22a and 22b of the input wiring circuit 22 extending from the recording control section (not shown), and the recording data for one line described above is connected to the shift register 21a. is input serially in synchronization with the data clock signal. Here, if one drive circuit element drives 100 recording electrode lines 20a, a total of 24 drive circuit elements 21 will be required.

Each drive circuit element 21 has a cascade connection configuration in which each data output terminal 22'a is connected to the data input line 22a of the next stage drive circuit element 21, and data exceeding 100 bits is sent to the next stage drive circuit element 21. Shifted sequentially.

A latch clock signal input line 22c is connected to the next data latch 21b, and the N pieces of recording data input to the shift register 21a are latched into the data latch 21b in synchronization with the latch clock signal. Ru.

The AND circuit section 21c includes N AND circuits 21cl to 2.
The strobe signal input line 22d is connected to each AND circuit 21cl to 21cN.

The strobe signal is a signal output to control the ON period when the recording electrode line 20a does not need to be ON for the entire period of a 1-bit recording cycle. Each AND
The circuits 21cl to 21cN output an "H" signal when both the N-bit recording data output from the data latch 21b and the strobe signal are "H".

The driver section 21d includes N transistors TRI to TR.
N, each base terminal and AND circuit 2101~
Each output terminal of 21 cN is connected through a resistor. Then, the emitter terminals of each transistor TRI to TRN are connected to a bias power supply 23 with an output of 1200V in this example.
A collector terminal is connected to each of the N recording electrode lines 20a. The pull-down resistor section 21e includes N pull-down resistors RDI to RDN, and includes a driver section transistor T.
Connect each collector terminal of RI to TRFI with each pull-down resistor R.
The configuration is such that they are each grounded via the DI-RDN.

Therefore, when the output signal from the AND circuits 21cl to 21cN is "H", the base terminal of the corresponding transistor TR becomes "H", and the transistor TR is turned on. As a result, the corresponding signal electrode line 20a is
A bias voltage of v is applied, and one black dot is formed as described later. Conversely, when the output signal of the AND circuits 21cl to 21cN is "L", the corresponding transistor TR is turned off, so the recording electrode line 20a connected thereto becomes the ground potential, and no black dot is formed.

Next, a 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 coil, a traveling wave magnetic field moving in the direction of arrow A is formed on the outer peripheral surface of the area where the excitation coil of the recording unit / ) U w is disposed. The magnetic toner d forms spikes and is conveyed in the opposite direction of the arrow. The magnetic toner d being conveyed reaches the recording section W after being cut to a predetermined thickness by the doctor blade 18 . At this time, the magnetic toner d is triboelectrically charged to a negative polarity.

Recording electrode lines 20a (see FIG. 8) are laid in parallel on the upstream side of the recording section W, and the drive circuit element 21 performs recording according to recording data for each recording electrode line 20a, as described above. Apply voltage selectively. In this case, when one bit of recording data is "H", the driver transistor TR is turned on, and a voltage of -200 V is applied to the corresponding recording electrode line 20a (electrode on state). As a result, a voltage of -50V is applied to the conductive sleeve 5a of the cylindrical electrode 5 facing the recording electrode wire 20a, so in the recording section W, a voltage of 150V is applied from the conductive sleeve 5a to the recording electrode wire 20a. A developing electric field is formed based on the potential difference.

On the other hand, when one bit of recording data is "L", the corresponding driver transistor TR is turned off and the recording electrode line 20 is turned off.
a becomes the ground potential (electrode off state). As a result, the potential difference seen from the conductive sleeve 5a of the cylindrical electrode 5 to the recording electrode line 20a at ground potential becomes -50V, and an electric field is formed in the opposite direction to the above-mentioned developing electric field.

The negatively charged magnetic toner d moves toward the higher potential. Therefore, the off-state recording electrode line 2O is at ground potential.
The magnetic toner d on a remains there and does not transfer, and only the magnetic toner d on the recording electrode line 2Oa in the ON state to which a voltage of -200V is applied is selectively transferred to the cylindrical electrode 5.
It metastasizes to the surface and forms black dots. In this way, a toner recorded image corresponding to the recorded data is formed on the surface of the cylindrical electrode 5.

In the above-described recorded image formation, in this example, the cylindrical electrode 5 is provided with the dielectric surface layer 5b, so that an image with high resolution can be stably formed in the following manner.

The developing electric field that forms the black dot is as shown in Figure 11.
The recording electrode line 20a has an intensity distribution characteristic in which the width (length in the main scanning direction) is maximum at the center and decreases approximately symmetrically toward both ends. If such a developing electric field acts on the cylindrical electrode surface layer 5b of this example, based on the characteristics shown in FIG. The volume electrical resistance g1d of the portion facing the dot (the center of the dot) is the minimum. the result,
Electric lines of force concentrate at the center of the dot.

FIG. 12(a) shows a comparative example with respect to this example, and shows the developing electric field formation state when no surface layer is provided on the cylindrical electrode 5 by cutting the recording part along the main scanning direction. FIG. In this case, since no surface layer is provided on the cylindrical electrode 5', the lines of electric force of the developing electric field are not focused at the center of the dot, and the radiation angle θ1 of the lines of electric force is generally quite large, about 45 degrees. As a result, the size of one dot is enlarged and the resolution of the image is lowered, and as shown in the figure, there is a possibility that black dots that should be separated by one white dot may be connected.

In this case, a method of reducing the distance between the electrodes may be considered in order to increase the resolution, but since magnetic toner is transported between the electrodes, there is a limit to reducing the distance.

On the other hand, in the recording section W of this example, as shown in FIG.
), the lines of electric force in the developing electric field formed by the turned-on recording electrode wires 20a are focused at the center of the dot as described above because the dielectric surface layer 5b is provided. The radiation angle θ2 of the electric lines of force is considerably smaller than the radiation angle θ1 described above. Therefore, even in the recording area W where a sufficient distance between the electrodes is ensured, the radiation angle of the lines of electric force is 01, which is small and the developing electric field has a sharp intensity distribution, resulting in dots with clear outlines and an appropriate size. A high-resolution toner recorded image can be stably formed on the surface of the cylindrical electrode 5.

In FIG. 1, the high-resolution toner recorded image formed as described above is conveyed to the image transfer section T with the rotation of the cylindrical electrode 5 in the counterclockwise direction a, and here the timing is set by the standby roll pair 3. The image is measured and transferred onto the paper that is re-fed. 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 5C.

In that case, the appropriate adjustment range is about 0 to -50V,
The closer to Ov, the higher the image density.

The magnetic toner d' remaining in the recording portion W without being transferred to the cylindrical electrode 5 side moves downstream as the traveling wave magnetic field advances, and is scraped off from the surface of the jacket member 151 by the scraping plate 19.
The toner falls onto the stirring roll 12 and is stirred and mixed with the stored toner.

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 shown in FIG.
It may be laid over an appropriate length region upstream from the recording portion W on the outer circumferential surface or downstream as shown by the two-dot chain line.

Furthermore, as shown in FIG. 14, the recess 2 can be formed without dividing the base 27.
7a, the drive circuit element 21 may be built in the recess 27a, and the recording electrode sheet 28 may be laid over a wide area from the upstream end of the outer cover member 29 to the recording section W.

Note that in order to prevent dust from entering the recess 27a,
What is necessary is to cover the cover 30 with the lid 30.

〔Effect of the invention〕

As described in detail above, according to the present invention, a plurality of recording electrodes are laid in parallel on a developer transport path that transports developer by a traveling wave magnetic field generating means that does not have a rotation mechanism, and the strength of the working electric field is increased. By arranging a cylindrical electrode with a surface layer made of a substance whose volume electrical resistance value changes depending on the temperature of the recording electrode to face the recording electrode, the lines of electric force of the electric field (development electric field) that transfers the developer at the electrode facing part are generated. can be focused at the center of the electrode. As a result, it is possible to form a developing electric field with a small radiation angle of electric lines of force and a sharp intensity distribution, and a high-resolution image is created by dots of appropriate size and clear outlines at the electrode facing part with a sufficient spacing between the electrodes. It becomes possible to form stably.

Further, by arranging the recording electrode drive circuit inside the developer conveying means, a large number of recording electrodes can be arranged in parallel at high density with a simple structure. Therefore, it becomes possible to manufacture a recording device that can form a high-resolution recorded image in a small size and at low cost.

In addition, since the developer is transported without using a rotating mechanism and it is a non-contact recording method, the durability of the recording device is improved and it is possible to stably form high resolution and clear images over a long period of time. can.

[Brief explanation of the drawing]

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 coil, and Figure 5 is the Graphs showing temporal changes in excitation magnetic field distribution curves due to excitation coils, FIGS. 6 and 7 are explanatory diagrams showing other embodiments of excitation coils, and FIG. 8 shows the above-mentioned recording image forming unit. A partially cutaway perspective view, FIG. 9 is a circuit diagram showing the drive circuit configuration of the recording image forming unit, FIG. 10 is a graph diagram showing the volume electric resistance value characteristics of the dielectric, and FIG. 11 is a circuit diagram showing the driving circuit configuration of the recording image forming unit. 12(a) and 12(b) are schematic explanatory diagrams showing the formation of the developing electric field in the comparative example and the recording image forming unit, respectively. , FIG. 13, and FIG. 14 are schematic sectional views showing other embodiments of the present invention. 1... Paper feed cassette 3... Standby roll pair 4... Transfer charger 5... Cylindrical electrode 5a... Conductive sleeve 5b... Surface layer 5c... Bias power source (cylindrical electrode side )8... Fixing device 10... Paper discharge tray 11... Unit container 12... Stirring roll 14.24.27... Base 14A, 14B... Divided base 15.15A, 15B, 28 .29...Outer cover member 16
...Coil part 16'...Coil 16#...Conducting wire part 18...Doctor blade 19...Scraping plate 20.25.28...Recording electrode sheet 20a...Recording electrode wire 20b ... Base film 21 ... Drive circuit element 22 ... Input wiring circuit 23 ... Bias power supply (recording electrode side) d ... Magnetic toner (or developer) d' ... Residual magnetic toner T ... Image transfer section U ... Recorded image forming unit Us ... Recording unit W ... Recording section

Claims (1)

[Claims] An excitation coil is disposed along the back surface of a developer conveyance member made of a non-magnetic material fixedly laid so that the surface thereof becomes a developer conveyance path, and a plurality of phase currents having different phases are applied to the excitation coil. a developer transporting means for transporting the developer by forming a magnetic field that waves along the surface of the developer transporting member; a plurality of recording electrodes arranged in parallel on the surface of the developer transporting member in a direction perpendicular to the developer transporting direction; a recording means comprising a drive circuit installed inside the developer conveying means for outputting a recording voltage to each of the recording electrodes according to input recording information; and a cylindrical electrode disposed opposite to the recording electrode with a predetermined gap maintained therebetween. By applying the recording voltage to an electrode facing portion where the recording electrode and the cylindrical electrode face each other, the developer transported by the developer conveying means to the electrode facing portion is transferred to the cylindrical electrode side. In the electrostatic recording device, the cylindrical electrode is formed by laminating a surface layer made of a substance whose volume resistivity changes depending on the strength of the electric field on the outer peripheral surface of the conductive substrate. electrostatic recording device.