JPH09230704A - Soaring system wet type toner developing device for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an electrostatic latent image of an electrophotography in a state of perfectly holding the developer in non-contact with a photoreceptor. SOLUTION: This device is composed so as to holding the wet type developer for the electrophotography carried on a developer carrier 4, in non-contact with a surface of the electrostatic latent image carrier forming the electrostatic latent image on the photoreceptor 2 provided on substrate 1, to make a centralized electric field generated in between a sharpened developing electrode 3 provided in its carrier and the electrostatic latent image, to make the developer 5 (consisting of carrier liquid and toner) producing liquid drops from a concentrating point, to make soaring toward the latent image carrier, and to develop the carrier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic visible image forming method, and more particularly to a toner flying type wet developing method which belongs to a type called a wet electrophotographic method but is completely novel.

[0002]

2. Description of the Related Art At present, electrophotographic technology is a core technology of an image forming method (hard copy technology), and its application field is expanding to not only copying machines but also printers and fax machines. However, all of the conventional electrophotographic techniques, whether wet or dry, are carried out by bringing the developer into direct contact with the photoreceptor (the Jumping developing method is said to be non-contact, but the gap is very small). However, since it is in contact with the photoconductor because it is oscillated by the AC bias voltage), there is a big problem that scumming is likely to occur, and the gradation is poor and the image becomes hard. There was a problem.
Japanese Patent Application Laid-Open No. 5-346692, which is related to our application, prevents consumption of a developer due to adhesion to a non-image portion of an electrostatic latent image, and has high density and high resolution with almost no background stain on the image. As a two-component wet development method capable of stably forming an image of the above, a two-component developer in which a charged toner is dispersed in a dielectric carrier liquid is raised on a developer carrier having irregularities on the surface and A wet developing method is characterized in that a developing solution is brought into contact with a photoconductor around a raised point, the charged toner is concentrated in the center of the raised portion by electrophoresis in a carrier solution, and the charged toner is attached to the image portion. However, even in this improved wet development method, since the carrier liquid adheres to the photoconductor around the ridge, the carrier liquid is transferred onto the paper, which is a problem peculiar to the wet electrophotographic system. It can not be completely avoided.
On the other hand, as an electrostatic visible image forming method, an inkjet recording method can be used in addition to the electrophotographic method.
In the conventional ink jet recording system, liquid or solid ink is generally ejected from a nozzle, a slit, a porous film or the like, and the ink is attached to paper, cloth, film or the like for recording. 2. Description of the Related Art Ink jet recording type printers are used everywhere because of their advantages such as low sound during use, small size and low cost. Further, further studies of printers have been vigorously carried out, and printers that can obtain good print quality on so-called plain paper such as report paper and copy paper have been put on the market as black monochromatic printers. Energetic research and development is also being conducted on printers. As an ink jet recording system, for example, US Pat. No. 3.060.429 discloses an opening / closing electrode for blocking or controlling a jet flow of an ink droplet and an electrode pair for adjusting an ink droplet flying path. Generating two pairs of charged ink droplets; accelerating the ink droplets from the nozzle containing ink toward the plate electrode while applying a high voltage between the nozzle and the plate electrode; And a step of supplying an ink drop onto a paper provided in front of the plate electrode immediately before the ink drop reaches the plate electrode, an electrostatic ink jet printing method for charging control of the ink drop is described. In addition, International Application No. PCT / AU92-665 (WO93 / 1186)
In the specification, a liquid having a thin particle concentration is supplied to a discharge area having a sharp shape, a voltage is applied to the discharge area to generate an electric field in the discharge area, and a dense aggregate of the particles is generated in the discharge area. Is described in the above liquid, and an ink jet printing method is described in which the liquid containing the concentrated agglomerates is ejected onto the surface to be printed. Such an image forming method develops an electrostatic latent image. It is not intended to obtain a visible image corresponding to the electrostatic latent image.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to carry a developer directly on an electrostatic latent image such as a photoreceptor when developing an electrostatic latent image, for example, electrostatic latent image development in a wet electrophotographic system. Since it is carried out by contacting with the body, the problem that a large amount of carrier liquid usually adheres to the background, which occupies most of the body, the problem that scumming easily occurs, and the gradation is poor and the image becomes hard Is to resolve.

[0004]

The object of the present invention is as follows. (1) "The surface of an electrostatic latent image carrier on which an electrostatic latent image is formed is formed on a photoconductor provided on a substrate. By contact, the wet developer for electrophotography carried on the developer carrier is held, and a concentrated electric field is generated between the sharpened developing electrode provided in the carrier and the electrostatic latent image. A flying type wet process for electrophotography, characterized in that droplets are generated from a concentration point in a developing solution composed of a carrier liquid and a toner, and the droplets are made to fly toward a latent image carrier and the carrier is developed in a non-contact manner. (2) "Toner developing method", wherein the formed toner image on the latent image carrier is transferred onto a sheet by some means, and if necessary, fixed later, the flying wet toner for electrophotography. Development method ", (3)" Electrostatic latent image formed with electrostatic latent image on photoconductor provided on substrate A transfer material such as paper is provided on the surface of the carrier, and the wet developer for electrophotography carried on the developer carrier is held in a non-contact manner with the sharp material provided in the carrier. A concentrated electric field is generated between the developed developing electrode and the electrostatic latent image, a droplet is generated in the developing solution from the concentration point, and the liquid droplet is caused to fly toward the latent image carrier, and the carrier is contactlessly contacted. (1) The method of developing a flying type wet toner for electrophotography, which is characterized in that the image is developed, (4) "The electrophotographic image of (1), wherein a single sharpened developing electrode is used. Flying type wet toner developing method for electrophotography ", (5)" Flying type wet toner developing method for electrophotography according to the above (1) characterized by having a plurality of sharpened developing electrodes ", (6)" single To move the developing electrode or multiple developing electrodes relative to the latent image in one-dimensional or two-dimensional directions (1) The method of developing a flying type wet toner for electrophotography, which is characterized in that the entire surface of the developer is developed, and (7) "The developing solution carrier also serves as a developing electrode. “Flying type wet toner developing method for electrophotography”, (8) “Developing electrode is 100 ^°
(1) A method for developing a flight type wet toner for electrophotography, characterized in that it is a thin tube formed of a conductive material having a specific resistance of Ω · cm or less, (9) “Development electrode is 10 ⁰
(1) The method for developing a flying type wet toner for electrophotography according to (1) above, characterized in that the needle is formed of a conductive material having a specific resistance of Ω · cm or less. (5) A method for developing a flying type wet toner for electrophotography, comprising a patterned printed circuit board, (11) "A common developing solution housing is provided for a plurality of the pattern electrodes. Characteristic above (1
0) Flying type wet toner developing method for electrophotography ”, (1
2) “The developing solution housing is partitioned for each of the pattern electrodes.
Method for developing wet type toner for electrophotography ", (13)
"The above-mentioned (1) method for developing a wet type toner for electrophotography, wherein the developing electrode is grounded or a bias voltage of either polarity is applied", (14) " A flying type wet toner development for electrophotography according to the above (1), characterized in that an existing positive type latent image is formed, and a bias voltage is applied to the developing electrode using a toner having a polarity opposite to the polarity of the latent image charge. Method, ”(15)“ a latent image is formed in a negative type in which a latent image charge exists in a non-image portion, a toner having the same polarity as the latent image charge is used, and a bias voltage is applied to the developing electrode. (1) The flying type toner development method for electrophotography of (1), (16) "The developing electrode is biased in a direction to further enhance the potential difference generated between the electrostatic latent image and the developing electrode. (1) Flying type wet toner developing method for electrophotography (17) "The latent image bearing member and / or the developing electrode is formed of a roller, and an image is formed by rotation of the roller, thereby forming an image by the flight type wet toner developing method for electrophotography". , (18) "The bias voltage is not a direct current (non-applied) but a pulse voltage, and the above-mentioned method (1) is a method for developing a wet type toner for electrophotography, and (19) is a" bias voltage ". Is achieved by applying a voltage in which a DC voltage of either polarity is superposed on the AC voltage as described above.
We develop from the tip by bringing a sharpening development electrode containing ink (developing solution) close to the latent image on the photoreceptor, which has been raised to several times the surface potential used in normal electrophotography. We found that the liquid becomes droplets and fly,
As a result of intensive studies, they have found that they can be applied to printers, fax machines, and copy machines, and arrived at the present invention.

The present invention will be described in detail below with reference to examples. FIG. 1 shows the basic form of the present invention. The surface potential of the latent image is ⁺ 500 to ⁺ 5,000 V, preferably ⁺ 1,
A 000 - ⁺ 3,000 V has achieved a high potential by increasing the film thickness compared to the photosensitive member (polarity (+) is not limited to) conventional electrophotographic technology. The developer is a wet developer used in a conventional electrophotographic copying machine.

The developer carrier is in this case made of an insulating material. The developer is held on the developer carrier.
Some of the carrier bearing member has a developing electrode which is constituted of a conductor having a resistivity of less than 10 ⁰ Ω · cm is provided. In FIG. 1, the fixing means is omitted. The developing electrode in this case consists of a metal needle as shown in FIG. 4, which in this case is grounded. The development electrode is 0.5 with respect to the surface of the photoconductor.
It is held at intervals of ~ 1.0 mm. When the latent image portion faces the developing electrode, an electric field (shown only in the vicinity of the developing electrode) as shown by the dotted line in FIG. 1 is generated, and the developing electrode is sharpened, so that the electric field is concentrated at the tip and toner is collected. It attracts with the carrier liquid, creates a string, and finally forms droplets,
It flies toward the latent image carrier. It lands on the latent image carrier and visualizes it. Although it is the response speed, in this case, a direct current (not alternating) electric field is applied, and the cycle of tearing and tearing into droplets is repeated. Therefore, it is determined according to this cycle. The response can be controlled by applying a pulse voltage described later. The droplet diameter varies depending on the shape and diameter of the electrode, but is in the range of 30 μ to 1,000 μ.

FIG. 2 shows an example in which paper is placed on the developing electrode side of the photosensitive member. In this case, there is an advantage that the transfer step described later is unnecessary, but the image resolution is slightly lowered, and There is a problem that it is difficult to narrow the distance between the photoconductor and the developing electrode because the paper is thick.

Although the examples of FIGS. 1 and 2 show the case where the developing electrode is a single single needle, the developing electrode may be a plurality of electrodes as shown in FIG. In the case of a plurality of electrodes, there is an advantage that the image surface can be developed correspondingly, and the developing speed becomes faster. In the case of a plurality of electrodes, each may be electrically isolated and each bias voltage may be applied, but they may all be connected to the same potential. The electrostatic latent image is two-dimensionally formed. To develop the entire surface, a plurality of electrodes whose alignment lines are perpendicular to the axial direction are moved in the axial direction of the photoconductor as shown in FIG. The body may be rotated, or, as shown in FIG. 6, a developing electrode may be provided over the entire width of the surface to be developed, and the photoreceptor may be entirely developed only by rotation. In the former case, the relative movement between the developing electrode and the surface to be developed is two-dimensional, and in the latter case, it is one-dimensional. The latter method, which requires only one-dimensional movement, has the advantage that the developing speed is faster.

In the example of FIG. 1, the toner image is directly formed on the photoconductor, and in this case, the transfer step is required during the entire image processing step as shown in FIG. If necessary, a fixing device may be provided as shown in FIG. Each of the developing electrodes is electrically conductive (specific resistance 10 ⁰ Ω ·
cm or less), a thin tube made of a material, or a needle-shaped tube as shown in FIG. In the case of the example shown in FIG. 3, the developing solution is inductively held in the thin tube,
It is excellent in that the developer can be easily supplied. Although not shown in the case of the example shown in FIG. 4, a separate developer supply unit is required.

FIG. 9 shows an example of a plurality of electrodes consisting of a printed circuit board and a housing on which fine line patterns of electrodes are engraved. When developing electrodes are integrated at a high density of 8 to 16 per 1 mm, a developing electrode formed of a printed board on which a conductive pattern is engraved is easy to manufacture and practical.
10 to 11 show examples of electrode end faces, the housing may be common to a plurality of electrodes as shown in FIG. 10, or each electrode may be partitioned as shown in FIG. It may be When the electrode is partitioned into each room, the developing electrode being developed affects the adjacent or adjacent developing electrode, so-called crosstalk,
There is an advantage to prevent. Further, as shown in FIG. 12, the housing may be omitted and the developer may be directly guided onto the electrodes.
In this case, another ink supply unit is required, but there is an advantage that clogging hardly occurs. The latent image carrier may be configured to obtain a surface image by rotating in a roller shape as shown in FIG. 7. When the latent image carrier has a roller shape, it has advantages that the latent image can be easily moved and renewed and can be repeatedly used.

The developing electrode must have a sharpened shape as a necessary requirement, but if it is satisfied, it may have a roller shape as shown in FIG. In the case of this roller shape, the whole has the same potential. FIG. 7 shows an example of a concrete construction of a practical machine. In this example, roller needle electrodes are used. If the latent image carrier is renewed, the developing electrode does not necessarily need to be renewed by rotation, but the rotating development electrode has an advantage that the developing solution is conveyed to the developing portion along with the rotation. Further, since the fixed portion is not used all the time but is renewed by rotation and used, the life of the developing electrode can be extended.

FIG. 13 shows an example in which a practical machine is constructed by using the developing electrode shown in FIG. 11, and its details are shown in FIG. The development electrode, in which multiple electrodes are aligned in the direction perpendicular to the axial direction of the photoconductor, moves in the axial direction and returns to its original position after development,
The photoconductor is rotated and the next row is developed. This is repeated to develop the entire surface. As shown in FIG. 13, the developing electrode is connected to an ink tank (developing solution tank) which moves together, and the developing solution is supplied from the tank. Each electrode is internally connected to the flexible printed board and connected to the machine body. Each electrode is lead to each pattern one by one, and the tip thereof may be connected to an individual bias voltage as required, or may be connected and connected to a common potential.

Next, the relationship with the form of the latent image will be described. In the case of the positive type latent image shown in FIG. 15, toner of opposite polarity is used. The developing electrode is normally grounded, but the background potential remains high (there are still electric charges on the background)
In this case, in order to cut off this, a low bias voltage having the same polarity as the latent image charge may be applied. However, since the effective potential difference between the latent image and the developing electrode is reduced, the flight must have a margin to the extent that the flight still occurs even if the potential is reduced. If the surface potential cannot be raised sufficiently and the surface potential alone does not fly,
As shown in FIG. 16, a bias voltage of opposite polarity may be applied to the developing electrode to increase the effective potential difference. FIG.
Is a case where the latent image is a negative type, and in this case, flight can be obtained by using toner of the same polarity and applying a high bias voltage of the same polarity and close to the latent image potential.

[0014]

As described in detail above, according to the present invention, the electrostatic latent image of electrophotography can be developed in the state where the photoconductor and the developing solution are completely out of contact with each other. There is a remarkable effect that a hard copy image having no gradation and good gradation is obtained. Also, unlike conventional wet electrophotography, only the image area has the developer, and therefore the solvent does not adhere,
This has the remarkable effect that the amount of solvent deposited on the paper is significantly reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic example of the present invention.

FIG. 2 is a diagram showing another example of the present invention.

FIG. 3 is a diagram showing details of an example of an electrode used in the present invention.

FIG. 4 is a diagram showing details of another example of the electrode used in the present invention.

FIG. 5 is a diagram showing an example of a multi-electrode developing electrode used in the present invention.

FIG. 6 is a diagram showing another example of the developing electrode used in the present invention.

FIG. 7 is a diagram showing an example of the present invention including a transfer step.

FIG. 8 is a view showing still another example of the developing electrode used in the present invention.

FIG. 9 is a diagram showing still another example of the developing electrode used in the present invention.

FIG. 10 is a diagram showing an example of an electrode end surface of a developing electrode used in the present invention.

FIG. 11 is a diagram showing an example of an electrode end surface of a developing electrode used in the present invention.

FIG. 12 is a diagram showing an example of still another electrode end surface of the developing electrode used in the present invention.

FIG. 13 is a diagram showing an example of a practical machine according to the present invention.

FIG. 14 is a diagram for explaining details of an example of a practical machine according to the present invention.

FIG. 15 is a diagram illustrating a case of developing a positive latent image according to the present invention.

FIG. 16 is a diagram illustrating a case where the present invention is implemented by applying a bias voltage.

FIG. 17 is a diagram illustrating a case of developing a negative latent image according to the present invention.

[Explanation of symbols]

 1 substrate 2 photoconductor 3 developing electrode 4 developing solution carrier 5 developing solution 6 paper 7 thin tube 8 needle 9 latent image carrier 10 transfer paper 11 housing 12 ink tank 13 ink pipe 14 toner polarity

Claims (18)

[Claims] 1. A wet developing method for electrophotography, which is carried on a developing solution carrier without contacting the surface of an electrostatic latent image carrier having an electrostatic latent image formed on a photoconductor provided on a substrate. To hold the liquid,
A concentrated electric field is generated between the sharpened developing electrode provided in the carrier and the electrostatic latent image, and a droplet is generated from the concentrated point in the developer liquid consisting of the carrier liquid and the toner to carry the latent image. A flying-type wet toner developing method for electrophotography, which comprises flying a toner toward a body and developing the carrier. 2. The flight type wet toner for electrophotography according to claim 1, wherein the formed toner image on the latent image carrier is transferred onto a paper by some means and then fixed if necessary. Development method. 3. A transfer material such as paper is provided on the surface of an electrostatic latent image bearing member having an electrostatic latent image formed on a photosensitive member provided on a substrate, and development is performed without contacting the surface. A wet developing solution for electrophotography carried on a liquid carrier is held, and a concentrated electric field is generated between a sharpened developing electrode provided in the carrier and an electrostatic latent image. 2. The flying-type wet toner developing method for electrophotography according to claim 1, wherein droplets are generated in the developing solution, and the droplets are made to fly toward the latent image carrier to develop the transfer material. 4. The flight type wet toner developing method for electrophotography according to claim 1, wherein a single developing electrode is used. 5. The flight type wet toner developing method for electrophotography according to claim 1, wherein a plurality of developing electrodes are provided. 6. The electrophotographic apparatus according to claim 1, wherein the entire surface is developed by moving a single developing electrode or a plurality of developing electrodes relative to the latent image in one-dimensional direction or two-dimensional direction. Flying type wet toner developing method. 7. The flying type wet toner developing method for electrophotography according to claim 1, wherein the developer carrier also serves as a recording electrode. 8. A developing electrode 10 ⁰ Omega · claim 1 for electrophotography flying type Liquid toner development method wherein a cm or less of the tubules formed of a conductive material having a resistivity. 9. A developing electrode 10 ⁰ Omega · claim 1 for electrophotography flying type Liquid toner development method wherein a cm or less of the needle is formed of a conductive material having a resistivity. 10. The flying type wet toner developing method for electrophotography according to claim 5, wherein the developing electrode comprises a printed circuit board having a patterned conductor. 11. A common developer housing is provided for a plurality of the pattern electrodes.
0. A flying type wet toner developing method for electrophotography according to 0. 12. A method of developing a flying type wet toner for electrophotography according to claim 10, wherein a developer housing is partitioned for each of the pattern electrodes. 13. The flying type toner development method for electrophotography according to claim 1, wherein the developing electrode is grounded or a bias voltage of either polarity is applied. 14. A positive electrostatic latent image is formed in which latent image charges are present in an image area, and a bias voltage is applied to a developing electrode by using toner having a polarity opposite to that of the latent image charges. The flying type wet toner developing method for electrophotography according to claim 1, wherein 15. A negative electrostatic latent image is formed in which a latent image charge is present in a non-image portion, and a bias voltage is applied to a developing electrode by using a toner having the same polarity as the latent image charge. The flying type wet toner developing method for electrophotography according to claim 1, wherein 16. The fly-type wet toner developing method for electrophotography according to claim 1, wherein the developing electrode is biased in such a direction as to further strengthen the potential difference generated between the electrostatic latent image and the developing electrode. 17. The flight type wet toner developing method for electrophotography according to claim 1, wherein the latent image carrier and / or the developing electrode are formed of a roller, and an image is formed by rotation of the roller. 18. The fly-type wet toner developing method for electrophotography according to claim 1, wherein a pulse voltage is applied as the bias voltage instead of a direct current having no voltage change.