JPH09314893A - Powder image recording method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new type of powder image forming method and an equipment which use a direct recording system and do not require frictional electrification of a toner and can record an image even on humid paper and conductor. SOLUTION: An image is formed by using an island-shaped electrode toner 93 having multiple fine conductive substances in a mutually insulated state at least on the surface. Charges injected into the fine conductive substances on the surface of the island-shaped electrode toner 93 from a toner bearing body 6a cannot move to the counter electrode side and retained as they are. Therefore, even if negative charges are injected from a low-resistance recording member, the toner is not electrified negatively and does not fly reversely, making possible recording to humid recording paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a plurality of minute openings independent from each other or in a series arranged between a toner carrier carrying toner and a counter electrode, and controlling the passage of toner through each minute opening. A voltage is applied according to an image signal to the control electrode portion of the toner flying control member having a plurality of control electrode portions, and the toner from the toner carrier is passed through the minute opening portion to the counter electrode. The present invention relates to a powder image recording method and apparatus for forming an image by transferring the toner to a recording medium and adhering it to a recording member located between the toner flight control member and the counter electrode.

[0002]

2. Description of the Related Art Conventionally, an image recording method called direct toning or toner projection has been known as a powder image recording method. In this image recording method, a voltage is applied to an image electrode provided around a hole or a slit, and the charged toner is moved (flies) through the hole or the slit to directly form an image on a recording member such as paper. It is.

Many proposals have been made for the image recording system. For example, Japanese Patent Publication No. 44-26333 discloses an apparatus in which a back electrode, a recording medium, a control grid, a mesh electrode, and a fur brush for supplying toner to the mesh electrode are sequentially arranged. In this apparatus, an insulating toner is frictionally charged by rotation of a brush, accelerated by an electric field formed in a space between a mesh electrode and a back electrode, is directed toward the back electrode, and forms an image on paper through a control grid. When the value of the electric signal applied to the control grid is changed, the electric field between the mesh electrode and the control grid is reversed, the toner does not fly and a background portion (white) is formed, and the image density is changed by adjusting the electric signal. You can also do it.

However, since the above-mentioned device uses the insulating toner, a large-scale device for rotating the brush is required to triboelectrically charge the toner. It is considered that the triboelectrification of the insulating toner is performed by the same method as in the two-component developing method or the one-component developing method. However, in these cases as well, since the carrier, the stirring mechanism, the developing roller, etc. are required, the apparatus is It will be a big deal. Further, since heat is generated by triboelectrification, it is necessary to use a resin having a relatively high melting point as the base resin of the toner, so it is difficult to lower the temperature during fixing and it is difficult to achieve energy saving. There is also.

On the other hand, for example, in the technique disclosed in Japanese Patent Laid-Open No. 58-44456, image recording is carried out by using a conductive magnetic toner which eliminates the drawback of the insulating toner which requires triboelectrification. . If a conductive toner is used, electric charge can be injected by an external electric field for easy charging without applying electric charge in advance, and triboelectric charging is not required. However, in the above technique, the toner carrier that carries the toner uses magnetic force to carry the toner, but since the transparent magnetic body is not completed, it is necessary to stack transparent color toners for full color printing. I can't.

In the technique disclosed in Japanese Examined Patent Publication No. 6-47298, a conductive non-magnetic toner is used, and as shown in FIG.
As shown in FIG. 2, a toner flight control member 15 having a counter electrode 11, a recording member 12, a minute opening 13 and a control electrode 14 for controlling the flight of the toner in the minute opening, and a covered wire 16 arranged at the bottom. There is disclosed a device in which a conductive roller 18 as a toner carrier, which is rotatably provided in a conductive case 17, is sequentially arranged. In this device, an AC voltage is applied to the covered wire 16 by an AC power supply 19 to induce electric charges in the conductive roller 18, and the electric conductive roller 18 is caused to fly in the closed space 20 to be in a cloud state. Then, the clouded toner is attached to the surface of the conductive roller 18.
The toner is attached to the conductive roller 18 by electrostatically adsorbing the toner on the conductive roller 18 by the image force of the electric charge of the clouded toner itself.

[0007]

However, according to the structure using the above conductive toner, when the resistance of paper or the like as the recording member is lowered in a high temperature and high humidity environment, the toner that flies and adheres to the paper In addition, electric charges of opposite polarity are injected from the paper, and the electric charges injected into the toner during flight are neutralized by the electric charges of opposite polarity, and finally the toner is charged to the opposite polarity to the desired polarity. When the electrostatic force in the direction of the toner carrier due to the electric charges of the opposite polarity becomes larger than the attractive force between the recording member and the toner, that is, the Van der Waals force, the toner flies in the opposite direction (hereinafter, referred to as reverse flight). Therefore, there is a problem in that the image density is significantly reduced.

Even when the conductive toner is laminated on the paper, electrostatic induction occurs due to the electric field around the toner, and the electric charge of the toner of the second or more layers attached to the surface of the paper is the first layer near the counter electrode. The charges move to the toner, and the charges having the same polarity as the above charges are generated in the toner of the second layer or more by electrostatic induction, and the charges also move to the toner of the first layer. This allows
The toners of the second layer and above are charged in the opposite polarity and fly in the opposite direction. That is, the conductive toner can basically form only one toner layer. Therefore, there is also a problem in that different color toners of yellow, magenta, and cyan cannot be stacked to form a full color.

Further, when the toner reversely flies as described above, the toner flying in the direction toward the recording member and the toner flying in the opposite direction elastically collide with each other in the air, the movement direction is changed, and the toner flies laterally to a long distance. The toner is scattered around the target image on the recording member (hereinafter referred to as dust). For this reason, there is a problem that the boundary line between the image and the non-image is blurred, which causes a lack of sharpness of the image.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image recording method and apparatus capable of recording an image on a paper or a conductor at high humidity.

In order to achieve the same object, the inventors of the present invention have a characteristic of being charged only positively or negatively within a voltage range used in a powder image recording method (hereinafter referred to as rectifying property). The present invention proposes a powder image recording method and apparatus using a rectifying toner. According to this method and apparatus,
Even when the resistance of paper or the like as a recording member is reduced in a high temperature and high humidity environment, charges of the opposite polarity are not injected into the toner adhering to the surface of the paper and the toner is not charged to the polarity opposite to the desired polarity. Therefore, the toner does not fly backward and can be recorded on a recording member having a low resistance. Even when toner is laminated to form an image, the second layer and the third layer attached to the surface of the recording member are used.
The toner of the layer is charged with the opposite polarity to the desired polarity and does not fly backward, and the toner can be laminated. Also, when an electric field is applied so that the toner flies only in one direction, the toner will not be charged to a polarity opposite to the desired polarity and will not fly backwards. The flying toner does not cause dust due to elastic collision,
A sharp image with a clear boundary between the image and the non-image can be obtained. The present invention provides a new powder image recording method and apparatus different from the above.

[0012]

In order to achieve the above-mentioned object, the invention of claim 1 is arranged between a toner carrier for supporting toner and a counter electrode, and a plurality of independent or series of plural members are provided. A voltage is applied according to an image signal to the control electrode portion of the toner flight control member having a minute opening portion and a plurality of control electrode portions that control the passage of toner through each minute opening portion, and the voltage is applied from above the toner carrier. Powder image recording method for forming an image by transferring the toner of No. 1 to the counter electrode side through the minute opening and adhering it to the recording member located between the toner flight control member and the counter electrode. In the above, a toner having a large number of minute conductive substances insulated from each other on the surface is used as the toner.

According to a second aspect of the present invention, a plurality of minute openings which are independent of each other or are arranged in series between the toner carrying member carrying the toner and the counter electrode, and the toner passing through each minute opening. A voltage is applied according to an image signal to the control electrode part of the toner flight control member having a plurality of control electrode parts for controlling, and the toner from the toner carrier is passed through the minute opening part to face the opposite side. The toner according to claim 1 is used as the toner in a powder image recording apparatus for forming an image by transferring the toner to an electrode side and adhering it onto a recording member located between the toner flight control member and the counter electrode. It is characterized by being used.

According to the first and second aspects of the present invention, when electric charges are injected into at least one of the large number of minute conductive substances on the toner surface, the large number of minute conductive substances are insulated from each other. Therefore, charges are not transferred between the minute conductive substances. Therefore, the charges injected into at least one of the minute conductive substances are retained. Therefore, when the resistance of the recording member decreases in a high-temperature and high-humidity environment, even if the toner having the opposite polarity is injected from the recording member to the toner flying and adhered to the recording member, the opposite side of the recording member Since the electric charge injected from the toner carrier at the time of flight remains held in the above-mentioned conductive substance, the toner is not charged to the opposite polarity. Further, even when the toner is laminated on the recording member, for example, the charges injected from the toner carrier to the toner of the second layer are still held by the minute conductive substance on the toner carrier side,
It does not move to the toner of the first layer. Further, even if an electric charge having the same polarity as that of the electric charge is generated in the toner of the second layer or more by electrostatic induction, the electric charge also does not move to the toner of the first layer. Therefore, the toner of the second layer is not charged in the opposite polarity. This also applies to the toners of the third layer and above, so that the toners of the second layer and above are not charged to opposite polarities.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a color printer which is an image recording apparatus will be described below. FIG. 1 is a schematic configuration diagram of a main part of the color printer according to the present embodiment. In this color printer, the recording paper 10 as a recording member is fed from the paper feed cassette 1 to the call roller 2
Paper is fed by the support roller 3
The belt-shaped counter electrode 4 supported by the rollers 1 and 32 is rotated to move on the control electrode 5 in the direction of the arrow. In order to make the belt-shaped counter electrode 4 have a recording paper conveying function, for example, a large number of holes may be formed in the counter electrode 4 and the paper may be adsorbed on the surface of the counter electrode by a vacuum device (not shown). Then, from the four toner containers 6 each having an opening at the upper portion, which are arranged below the control electrode 5 while being horizontally fed over the control electrode 5, the color toner (the toner particles flying under the control of the control electrode 5) ( Hereinafter, this will be referred to as toner), and recording is performed on the recording paper 10.

A voltage is applied to the counter electrode 4 via a conductive support roller 31 by voltage applying means (not shown). The above four toner containers 6 are Y, M, C, B
K toners are stored.

The toner attached to the recording paper 10 is sent between a heat roller 7 and a pressure roller 8 as a fixing device to fix the image.

FIG. 2 is an explanatory diagram of a recording portion of the same color printer, which is provided with the counter electrode 4, the control electrode 5, and the toner carrier 6a provided in the toner container 6 for one color. The control electrode 5 is for controlling the flight of the toner by applying an electric field to the toner on the toner carrier. In this embodiment, the island-shaped electrode toner 93 is used as the toner, and the island-shaped electrode toner 93 will be described later. The control electrode 5 has a thickness of 7 which is an insulator.
25 μm thick on both sides of 5 μm polyimide film 52
It is possible to form a hole 54 having a diameter of 120 μm, for example, by using a YAG laser or the like at a predetermined position at the end by exposing the electrode pattern on each copper foil by exposure, and then etching. Then, the copper foil on the counter electrode 4 side is used as an image electrode 51 to which a voltage is applied according to an image signal, and the copper foil on the toner carrier 6 a side is prevented from flying in a portion other than directly below the hole 54. To be the shield electrode 53. The shield electrode 53 is, for example, a toner carrying member so that the electric field applied to the toner in a portion other than immediately below the hole 54 does not fall below the flight start electric field and the toner does not fly even if a voltage for image recording is applied to the counter electrode and the image electrode. Body 6a
Ground similarly to. In the example of FIG. 2, the distance between the counter electrode 4 and the image electrode 51 is 200 μm, and the distance between the shield electrode 53 and the surface of the toner layer is 100 μm.

Next, details of the image electrode 51 in this embodiment will be described. FIG. 3 shows an example of control electrodes for one color. In FIG. 3, the left-right direction is the recording paper conveyance direction (hereinafter, referred to as the paper conveyance direction) as indicated by a white arrow A.
It is. This example is an example of 600 dpi. 600
In dpi, the dot pitch is 42.3 μm,
Image electrode 51 diameter 180 μm, hole 54 diameter 120
In order to realize the size of μm, eight holes 54 in a direction orthogonal to the paper conveyance direction (hereinafter referred to as the paper width direction) are arranged so as to be inclined at a predetermined angle with respect to the paper conveyance direction, and the center of the hole is conveyed. Eight adjacent image electrodes are arranged at intervals so as not to overlap each other in the direction. That is, the pitch d1 of the centers of the holes 54 in the paper width direction is 60.
The inclination angle and the interval are set so as to be 42.3 μm corresponding to 0 dpi. Further, the pitch of the centers of the holes 54 in the paper transport direction is 42.3 μ which is equivalent to 600 dpi.
It is set to be an integral multiple of m. Regarding the size of the group of the image electrodes 51, the distance w1 between the hole center on the most upstream side and the hole center on the most downstream side in the paper transport direction is 1.1844 mm, and the width in the paper width direction is 210 mm, which is the same as the A4 width. And
Each of the image electrodes 51 is connected to an IC driver (not shown). In the same color printer, the image electrodes 51 having the above configuration are arranged for each color.

In the present embodiment, as a toner for recording on a recording paper, a toner having a large number of minute conductive substances in an island shape on the surface of an insulating substance (hereinafter, referred to as an island electrode). A toner 93 is used. Less than,
The operation when the island-shaped electrode toner 93 is used will be described.

The island-shaped electrode toner 93 has, for example, styrene and acrylic resin as a base resin, a coloring material dispersed therein, and pulverized by an ordinary pulverization method to an average particle size of 7 μm, and then the surface thereof is made of hydrophobic silica. Can be sprinkled with 1 wt% to prepare. These materials are usually electrophotographic (Carlson method)
It is often used as a material for toner, and is easily available and inexpensive. Also, this manufacturing method is general and does not require new equipment. It is known that in the toner thus formed, water molecules are adsorbed on the hydrophobic silica on the surface of the toner, and the water molecules retain an electric charge and are charged. This is for the following reason.

Since silica is originally hydrophilic, a network of water molecules is formed on the surface of the toner under high humidity to make it electrically conductive, and all electric charges leak. However, in the case of hydrophobically treated hydrophobic silica, the network of water molecules is cut between the silica, so that the isolated water molecules or groups of water molecules retain their charge and are charged even in high humidity (The Role). of Water in the Triboelectric Charging
of Alkylchlorosilane-Treated Silicas as Toner Surf
ace Additives, RPNVeregin et al., Journal of Imagin
g Science and Technology, Vol.39, No.5, September / Oct
Ober 1995). This isolated water molecule or group of water molecules can be regarded as a conductive island floating in an insulating sea. Therefore, this toner is called an island-shaped electrode toner 93, and the conductive material dispersed in the island shape is called an island-shaped electrode 93a.

Next, the results of measuring the characteristics of the island-shaped electrode toner 93 formed by the above method will be described. In the measurement, as shown in FIG. 4 (a), the island-shaped electrode toner 93 is set in a concave portion having a diameter of 10 mm and a depth of 0.1 mm provided on the toner carrier 6a, and above the toner carrier 6a, 1
The measurement was performed using an apparatus in which the counter electrode 4 was installed with a space of mm.

First, the toner carrier 6a is grounded, a predetermined voltage is applied to the counter electrode 4 for 1 second, and thereafter, the mass of the toner that has jumped and adhered to the insulating film on the counter electrode (hereinafter referred to as the toner flying amount). The above applied voltage is -2 in the same device as that for measuring the toner of ordinary electrophotography.
The measurement was performed while changing the range of kV to 2 kV. For comparison, the same measurement was performed using conductive toner 91 made by Ricoh, conductive toner RIFAX9000 (trade name), the rectifying toner 90 exhibiting the rectifying property, and the medium resistance toner 92. Here, as the rectifying toner 90, a strong polymer of styrene, an acrylic monomer, and a cationic polymer represented by the following formula is used as a base resin, and a coloring material is dispersed therein,
The surface thereof was formed by a usual crushing method and then sprinkled with silica.

Embedded image As the medium resistance toner 92, PEO-1 (trade name) manufactured by Sumitomo Seika, which is a polyethylene oxide having a molecular weight of 10,000, is used as a base resin, a pigment is dispersed therein, and silica is externally added after finely powdered. What was formed was used. Further, when the device of FIG. 4A is used when the conductive toner 91 is used, charges of the opposite polarity are injected into the toner that has been ejected and adhered to the counter electrode, resulting in the inverse flight. Therefore, only when the measurement is performed using the conductive toner 91, as shown in FIG. 4B, the counter electrode 4 having the insulating film 41 adhered to the surface of the toner carrier 6a is 1 mm above the toner carrier 6a. The measurement was performed using an apparatus installed at intervals. The result is shown in FIG. From this result, the above-mentioned island-shaped electrode toner 93
Unlike a rectifying toner, which does not fly at a positive voltage even at 2 kV and flies only when a negative voltage is applied, like a conductive toner or a medium resistance toner, it flies when a positive or negative voltage is applied. I understand that (Hereinafter, margin)

Next, the applied voltage is fixed at -2 kV,
FIG. 6 shows the result of similarly measuring the toner flying amount while changing the voltage application time to 0.1 to 1000 msec. From this result, it is understood that the island-shaped electrode toner 93 flies in a short time like the conductive toner 91 and the rectifying toner 90, unlike the medium resistance toner 92 which hardly flies in the voltage application time of 10 msec or less. .

Next, FIG. 7 shows the result of measuring the flying amount of toner after the pulse voltage was applied to the opposite electrode 7 times to fly the toner 7 times by 0.8 mg each. From this result, unlike the conductive toner 91 in which the flying amount of the toner is substantially constant regardless of the number of times the pulse voltage is applied, the island electrode toner 93 is applied with the pulse voltage similarly to the rectifying toner 90 and the medium resistance toner 92. The flying amount of toner increases in proportion to the number of times. Here, it is observed that even when the conductive toner 91 is used, a sufficient amount of toner flies every time a pulse voltage is applied. From this, when the conductive toner 91 is used, the toner of the second layer and above flies once, but reversely flies after adhering to the counter electrode side, whereas the island electrode toner 93, the rectifying property. When the toner 90 and the medium resistance toner 92 are used, it is considered that the toners of the second and higher layers also remain attached to the counter electrode without flying backward. That is, it can be said that three types of toner other than the conductive toner 91 can be stacked.

The characteristics of the above four types of toner will be described in detail based on the above measurement results. First, the operation of the above four types of toner when the toner carrier is grounded and a negative voltage −V is applied to the counter electrode 4 will be described with reference to FIGS. 8 and 9. 8 is an explanatory diagram of the movement of the electric charges injected into the conductive toner, and FIG. 9 is an explanatory diagram of the movement of the electric charges injected into the island-shaped electrode toner. By applying the above voltage, a positive charge is induced in the toner carrier and is injected into the toner in contact with the toner carrier 6a. At this time, as shown in FIG. 8, in the conductive toner 91, the injected positive charges move on the surface of the toner and move to the counter electrode 4 side, and in that state, the toner flies toward the counter electrode 4. In the case of the rectifying toner 90 as well as in the case of the conductive toner 91, the injected positive charges move on the surface of the toner and move to the counter electrode side. Further, in the case of the medium resistance toner 92, it is considered that the flying starts while the positive charge is moving on the surface of the toner. On the other hand, in the island-shaped electrode toner 93, as shown in FIG. 9, it is considered that the positive charges injected into the island-shaped electrode 93a cannot move to the counter electrode side and fly as they are.

Next, the operation after the above-mentioned four kinds of toner have been ejected and adhered to the counter electrode 4 will be described with reference to FIG. Note that FIG. 10 is an explanatory diagram of the operation when the conductive toner, the medium resistance toner, the rectifying toner and the island-shaped electrode toner are attached to the counter electrode of the apparatus of FIG. In the case of the conductive toner 91, if the surface of the counter electrode 4 is not made of an insulating material as described above, a negative charge is immediately injected from the counter electrode 4 to the toner attached to the counter electrode 4, and the toner is carried. The positive charge injected from the body 6a is neutralized by the negative charge, and the conductive toner 91 is finally charged to the opposite polarity. Then, the conductive toner 91 charged to the opposite polarity is subjected to an electrostatic force directed from the counter electrode toward the toner carrying member by the surrounding electric field and flies toward the toner carrying member (hereinafter referred to as reverse flying). On the other hand, medium resistance toner 9
In the case of 2, a negative charge is injected from the counter electrode 4 to the toner attached to the counter electrode 4, but it takes time to inject the charge, so that the pulse voltage application time used for the normal image formation is In the range, the negative charges that fly backward are not injected, and remain on the counter electrode 4 due to the adhesive force between the counter electrode 4 and the medium resistance toner 92. Further, in the case of the rectifying toner 90, since a negative charge is not injected into the toner, the electrostatic force toward the counter electrode 4 while the toner is positively charged and the adhesive force between the toner and the counter electrode 4 are generated. Stay on the surface of the counter electrode 4. Also, the island-shaped electrode toner 9
In the case of 3, the island-shaped electrode 93a in contact with the counter electrode 4
The negative charge is immediately injected into the toner carrier 6
Since the positive charge remains on the island-shaped electrode on the side closer to a, the electrostatic force due to the negative charge and the electrostatic force due to the positive charge are balanced and stay on the counter electrode 4 due to the adhesive force between the toner and the counter electrode 4. it is conceivable that.

Next, the case where toner is laminated on the surface of the counter electrode 4 will be described with reference to FIG. Note that FIG. 11 is an explanatory diagram of the operation when the conductive toner, the medium resistance toner, the rectifying toner and the island-shaped electrode toner are laminated on the counter electrode of the apparatus of FIG. As shown in FIG. 11, the conductive toner 9
In the case of 1, if the insulating film 41 is present on the surface of the counter electrode 4, the first layer remains, but when the toner of the second layer adheres, the positive charge injected from the toner carrier 6a moves to the first layer, and A positive charge is generated by electrostatic induction and moves to the first layer, and a negative charge remains in the toner of the second layer, and the toner has a reverse polarity, that is, is negatively charged and flies backward. In the case of the medium resistance toner, it takes time for the positive charge to move to the first layer, and therefore the first layer is not negatively charged within the range of the pulse voltage application time used for normal image formation. It stays on the toner of the first layer. In the case of the rectifying toner 90, the positive charge injected from the toner carrier 6a into the toner of the second layer moves to the toner of the first layer, unlike when the toner directly adheres to the counter electrode. This is because the opposite electrode and the toner are made of different materials, so that movement of charges is blocked and positive charges are held in the toner, but since the toners are made of the same material, the charges can move to each other. However, after the toner of the second layer becomes electrically neutral, a negative charge is not injected into the toner of the second layer due to electrostatic induction.
It remains on the toner of the first layer as it is due to the adhesive force. In the case of the island-shaped electrode toner 93, the positive charge of the toner of the second layer held on the island-shaped electrode 93a does not move to the toner of the first layer, and the toner of the second layer is positively charged. While remaining as it is, it remains on the counter electrode 4 due to the electrostatic force directed to the counter electrode and the adhesive force between the toner and the counter electrode.

Table 1 is a summary of the characteristics of the above-mentioned four types of toner. When the four characteristics, specifically, fast charge injection, recording on a conductor, full color capability, and low material cost are satisfied, it is indicated by ◯, and when not satisfied, by x. From this table, the island-shaped electrode toner 93 has the highest charge injection rate, can be recorded on the conductive recording material, allows full-color printing, has a wide selection range of materials, is easy to manufacture, and is the most excellent. Can be said.

[0031]

[Table 1]

Next, in the recording portion of the color printer of FIG. 1 shown in FIG. 2, the island-shaped electrode toner 9 as described above is used.
The operation when 3 is used will be described. First, the toner carrier 6 a and the shield electrode are grounded, and a constant voltage, for example −400 V, is applied to the counter electrode 4. In addition, the image electrode 5
When a constant voltage, for example, −120 V is applied to 1 as well, and when recording on the recording paper 10, I (not shown)
An image signal pulse voltage of, for example, −60 V is applied from the C driver. At this time, the image electrode 51 has -12
The voltage of -180V is applied by being superimposed on the voltage of 0V. Then, a positive charge is induced in the island electrode toner 93 by the electric field formed on the surface of the toner layer, and the electrostatic force in the direction of the counter electrode 4 formed by the electric field acting on the charge is applied to the island electrode toner. Acts on 93. When this electrostatic force exceeds the sum of the adhesive force (van der Waals force) between the toner or the toner carrier 6a and the gravity, the island-shaped electrode toner 93 separates from the toner layer and the electric force indicated by the dotted line in the figure. It flies along the line and adheres to the recording paper 10. By attaching the island-shaped electrode toner 93 in this manner, it is possible to record on the recording paper 10.

In this embodiment, the island-shaped electrode toner 93 is used.
After the toner flies and adheres to the recording paper 10, the island-shaped electrode toner 93 is not negatively charged as described above even when the resistance of the recording paper 10 is low. Therefore, since electrostatic force in the direction toward the toner carrier 6a does not work, the toner does not fly in the opposite direction, and recording can be performed on the recording paper 10 having low resistance.

Here, in the color printer of FIG.
When a conductor such as an aluminum foil is used as the recording paper 10 or a plain paper which is placed in a high temperature and high humidity environment test room at 30 ° C. and 90% RH and left for 4 hours is used as the counter electrode 4, Even when printing was performed by applying a voltage of 400 V and -180 V to the image electrode, a high image density print could be obtained.

In the color printer of this embodiment, when full-color printing is performed, the above operation is repeated four times using yellow, magenta, cyan, and black toners. In this case, as described above, the toner of the second layer holds the electric charges injected from the toner carrier 6a to the island-shaped electrodes 93a of the toner even after the toner adheres to the recording paper, and the electrostatic induction causes The second layer toner is never negatively charged. Similarly, the toner on the third and subsequent layers is not negatively charged. Therefore, the electrostatic force in the direction toward the toner carrier does not act on the toner of the second and subsequent layers, and the toner does not fly in the opposite direction. Therefore, it is possible to stack toner.

Further, as described above, since the toner does not fly in the opposite direction, there is no elastic collision between the toner heading in the direction of the counter electrode 4 and the toner flying in the opposite direction.
The generation of dust can be suppressed.

Here, in the color printer of FIG.
While moving the conveyor belt also serving as the counter electrode 4 at 55 mm / sec, a pulse voltage of −60 V is applied from an IC driver (not shown) to the image electrode 51 to which a fixed voltage −120 V is applied according to an image signal. By applying each for 0.77 msec, a full-color print with high image density and no dust could be obtained. The printing speed at this time was 10 sheets per minute.

As a comparative example, when full-color printing was similarly performed using the rectifying toner 90 formed by the above-described method, a color print with substantially the same image quality was obtained, but the cost of toner per sheet was It is 10 to 100 times as large as the toner used in a normal printer.

When full-color printing was similarly performed using the medium resistance toner 92 formed by the above method, the obtained print had a very low image density. This is because the pulse voltage application time of the pulse voltage applied to the image electrode was too short to inject the electric charge to the extent that the medium-resistance toner flies.

Also, a conductive toner RIFAX manufactured by Ricoh
When single-color printing of black only was performed under the same conditions using 9000 (trade name), a large amount of toner was scattered on the left and right of the printed line image, and the sharpness was very poor. The reason why the dust frequently occurs is that the flying toner and the backward flying toner elastically collide in the air and land on an unexpected place.

In the present embodiment, only the island-shaped electrode toner 93 formed by the above method has been described.
The same effect can be obtained if the toner has a large number of minute electrically conductive substances that are insulated from each other on the surface. Further, the image forming apparatus is not limited to the image forming apparatus having the configuration shown in FIG. 1, but may be any image forming apparatus as long as it is an image forming apparatus that performs recording by flying toner toward recording paper. Even if there is, the same effect can be obtained.

[0042]

According to the first and second aspects of the present invention, when a charge is injected into at least one of a large number of minute conductive substances on the toner surface, the charge is transferred to other conductive substances on the toner surface. It is retained without moving. Therefore, even when the resistance of the recording member is lowered in a high temperature and high humidity environment, the charge injected from the toner carrier during the flight is still held in the conductive material on the side opposite to the recording member. Does not have a polarity opposite to the desired polarity. Therefore, there is an excellent effect that the toner does not fly backward and can be recorded on a recording member having a low resistance. Even when the toners are laminated to form an image, the toners of the second layer and above are not charged by the opposite polarity to the desired polarity and do not fly backward, and the toners can be laminated. Thus, for example, different color toners can be laminated to obtain a good full-color print. Further, since the toner is not charged to the opposite polarity to the desired polarity and does not fly backward, the toner flying toward the recording member does not elastically collide with the toner flying backward, thus causing no dust. A sharp image with clear boundaries between and is obtained.

[Brief description of drawings]

FIG. 1 is a front view illustrating a schematic configuration of a color printer according to an embodiment.

FIG. 2 is an explanatory diagram of a one-color recording unit of the printer.

FIG. 3 is a plan view of one color control electrode array of the printer.

FIG. 4A is an explanatory diagram of a device for measuring characteristics of island-shaped electrode toner, medium resistance toner, and rectifying toner. FIG. 3B is an explanatory diagram of a device for measuring characteristics of conductive toner.

FIG. 5 is an explanatory diagram showing the dependency of the toner flying amount on the applied voltage to the counter electrode, measured with the apparatus of FIG.

6 is an explanatory diagram showing the dependence of the amount of toner flying on the pulse voltage application time to the counter electrode, measured by the apparatus of FIG.

FIG. 7 is an explanatory diagram showing the dependence of the amount of toner flying on the number of times a pulse voltage is applied to the counter electrode, measured with the apparatus of FIG.

FIG. 8 is an explanatory diagram of movement of charges injected into the conductive toner.

FIG. 9 is an explanatory diagram of the movement of charges injected into the island-shaped electrode toner.

10 is an explanatory diagram of an operation when a conductive toner, a medium resistance toner, a rectifying toner and an island-shaped electrode toner are attached to a counter electrode of the apparatus of FIG.

11 is an explanatory diagram of an operation when a conductive toner, a medium resistance toner, a rectifying toner, and an island-shaped electrode toner are laminated on a counter electrode of the apparatus of FIG.

FIG. 12 is a principle explanatory view of an example of a powder image recording apparatus using a conductive toner which has been conventionally used.

[Explanation of symbols]

 1 Paper Feed Cassette 10 Recording Paper 2 Calling Roller 3 Conveying Roller Pair 4 Counter Electrode 5 Control Electrode 51 Image Electrode 52 Polyimide Film 53 Shield Electrode 54 Hole 6 Toner Carrier 7 Heat Roller 8 Pressure Roller 90 Rectifying Toner 91 Conductive Toner 92 Medium resistance toner 93 Island electrode toner

Claims (2)

[Claims] 1. A plurality of independent or continuous micro-apertures arranged between a toner carrying member carrying a toner and a counter electrode and a plurality of control electrode parts for controlling toner passage through the respective micro-apertures. A voltage is applied to the control electrode portion of the toner flight control member having the following according to an image signal, and the toner from the toner carrier is passed through the minute opening to the counter electrode side. In a powder image recording method for forming an image by adhering it on a recording member located between a toner flight control member and the counter electrode, a toner having a large number of minute conductive substances insulated from each other on the surface thereof Is used as the toner, and a powder image recording method is provided. 2. A plurality of independent or continuous micro-apertures arranged between a toner carrier for supporting a toner and a counter electrode, and a plurality of control electrode parts for controlling toner passage through the respective micro-apertures. A voltage is applied to the control electrode portion of the toner flight control member provided with, in accordance with an image signal, and the toner from the toner carrier is transferred to the counter electrode side through the minute opening. In a powder image recording apparatus for forming an image by adhering it on a recording member located between a toner flight control member and the counter electrode, the toner according to claim 1 is used as the toner. Powder image recording device.