JP2008304778A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of enhancing flare uniformity on an electrode in a flare developing system, thereby improving toner scattering and image unevenness by using a flare developing system capable of obtaining high image quality (high resolution dot reproductivity). <P>SOLUTION: The developing device includes a toner carrier 31 that moves while carrying the toner for developing an electrostatic latent image formed on an electrostatic latent image carrier. The toner carrier 31 includes: a surface layer 43; and two kinds of patterns of non-conductive electrodes 42A and 42B disposed under the surface layer; and an insulating layer 41 under the electrode patterns. The developing device also includes a power supply means 59 for supplying a voltage to the electrodes so that the electrical field between the two kinds of electrodes may vary in terms of time, and the toner is separated from the surface of the toner carrier by the electrical field generated between the electrodes so as to form a cloud. Regarding the moving toner carrier 31, adjacent pitch widths (a) and (b) between two kinds of electrodes are different from each other (a>b). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device of an image forming apparatus using an electrophotographic process, and an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a composite machine including the developing device.

  Conventionally, there are many developing methods used in developing devices of image forming apparatuses using an electrophotographic process, including those that have been put into practical use. Among them, typical development methods include the following.

[Two-component development method]
This method uses a two-component developer composed of a toner and a magnetic carrier, is very suitable for high-speed development, and is the current mainstream method for medium-speed and high-speed output machines. In order to aim at high image quality with this two-component development method, the state of the developer at the contact portion with the electrostatic latent image needs to be very fine. For this reason, the carrier particles are now being reduced in diameter, and carriers of about 30 μm are beginning to be used on a commercial level. However, the demand for higher image quality is increasing, and the required dot size of the pixel itself needs to be equal to or smaller than the current carrier particle size. Carrier particles need to be small. However, as the carrier diameter is reduced, the permeability of the carrier particles decreases, so that carrier detachment from the developing roller easily occurs, and when the detached carrier particles adhere to the electrostatic latent image carrier. In addition to image defects due to the carrier adhesion itself, various side effects such as scratching the electrostatic latent image carrier from the origin are caused.

In order to prevent this carrier detachment, attempts have been made to increase the magnetic permeability of carrier particles from the material surface and to increase the magnetic force of the magnet included in the developing roller. Development is extremely difficult due to this balance. In addition, due to the downsizing of the development roller, the diameter of the developing roller is becoming smaller and smaller, so it becomes difficult to design a developing roller having a strong magnetic field configuration that can completely prevent carrier detachment. ing.
In the first place, the two-component development system is a process of forming a toner image by rubbing the ears of a two-component developer called a magnetic brush against an electrostatic latent image. Unevenness tends to occur in the developability of isolated dots.

Although an image quality can be improved by forming an alternating electric field between the developing roller and the electrostatic latent image carrier, it is difficult to completely eliminate fundamental image unevenness such as unevenness of the ears of the developer.
Also, in the process of transferring the toner image developed on the electrostatic latent image carrier to a transfer material or intermediate transfer body, and the process of cleaning the toner remaining on the electrostatic latent image carrier after the transfer, transfer efficiency and cleaning In order to improve the efficiency, it is necessary to reduce the non-electrostatic adhesion between the electrostatic latent image carrier and the toner as much as possible. As a method of reducing the non-electrostatic adhesion between the electrostatic latent image carrier and the toner, it is known that reducing the friction coefficient of the surface of the electrostatic latent image carrier is effective. Further, since the spikes of the two-component developer smoothly pass through the developing portion, the development efficiency and the dot reproducibility are extremely deteriorated.

[Single component development system]
This method uses a one-component developer made of toner, and is the mainstream method of current low-speed output machines because the mechanism is small and light. In this one-component development method, in order to form a toner thin layer on the developing roller, a toner regulating member such as a blade or a roller is brought into contact with the developing roller. At that time, friction with the developing roller or the toner regulating member is caused. The toner is charged. The charged toner layer formed as a thin layer on the developing roller is transported to the developing unit and developed. The development methods here are roughly divided into a contact type and a non-contact type, the former being a non-contact between the developing roller and the electrostatic latent image carrier, and the latter being in contact. In any method, the toner layer thinned on the developing roller is sufficiently pressed, so that the toner responsiveness to the electric field in the developing unit is very poor. Therefore, in general, in order to obtain high image quality, it is mainstream to form a strong alternating electric field between the developing roller and the electrostatic latent image carrier. However, even if this alternating electric field is formed, the electrostatic latent It is difficult to stably develop a certain amount of toner on an image, and it is difficult to uniformly develop high resolution minute dots.

  Further, in this one-component development method, when a toner thin layer is formed on the developing roller, a very large stress is applied to the toner, so that deterioration of the toner circulating in the developing device is very fast. As the toner deteriorates, unevenness and the like are likely to occur in the process of forming a toner thin layer on the developing roller.

[Hybridization of the above two-component development method and one-component development method]
In order to compensate for the shortcomings of the two-component development method and the one-component development method, several hybrids such as the conventional technique described in Patent Document 1 (Japanese Patent Laid-Open No. 03-1005515) have been proposed. Although such a hybrid increases the size and the number of parts of the developing device itself, some problems are overcome. However, in the developing portion, the same problem as that of the one-component developing method, that is, difficulty in developing high-resolution minute uniform dots remains.

[Toner cloud in development section]
As a method of developing high-resolution minute uniform dots, there is a conventional technique described in, for example, Japanese Patent Laid-Open No. 03-113474. In contrast to the hybrid configuration described above, by installing a wire to which a high frequency bias is applied to the developing unit, toner clouding is performed in the developing unit, thereby realizing high-resolution dot developability. With this method, the construction of the developing device is complicated, but it is considered that highly stable and high-quality development can be realized. However, in this method, there is no force to bind the clouded toner to the development area, and toner scattering becomes a big problem.

[Toner cloud using electric curtain]
In order to form the most efficient and stable toner cloud, Patent Document 3 (Japanese Patent Laid-Open No. 03-21967) and known examples cited therein propose a method of forming an electric field curtain on a rotating roller. Has been. This method can be interpreted as being extremely excellent for obtaining a small-sized and high-quality development. However, as a result of intensive studies by the present inventors, in order to obtain an ideal high image quality, It has been discovered that conditions such as development must be limited. In other words, if image formation is performed under conditions other than the appropriate conditions, not only the effect is not obtained, but also poor image quality is provided.

Japanese Patent Laid-Open No. 03-100575 Japanese Patent Laid-Open No. 03-113474 Japanese Patent Laid-Open No. 03-21967

The present invention has been made in view of the above circumstances, and uses a flare development system capable of realizing higher image quality (high resolution dot reproducibility) than the conventional development system described above. An object of the present invention is to provide a developing device having a configuration capable of enhancing the uniformity of flare on the electrode and thus improving toner scattering and image unevenness.
In addition, the present invention uses a flare development method capable of obtaining a high-quality image with an overwhelmingly excellent dot reproducibility compared with the conventional development method. In the flare development method, the flare uniformity on the electrode is improved. An object of the present invention is to provide an image forming apparatus that is equipped with a developing device that can improve toner scattering and image unevenness and that can stably form a high-quality image over a long period of time.

In order to achieve the above object, the present invention employs the following solutions.
The first means of the present invention is arranged to face the electrostatic latent image carrier and moves while carrying toner for developing the electrostatic latent image formed on the electrostatic latent image carrier. A developing device having a toner carrier, wherein the toner carrier has a surface layer, two types of non-conductive electrode patterns are provided under the surface layer, and an insulating layer is provided under the electrode pattern. And a voltage supply means for supplying a voltage to the electrodes so that the electric field between the two types of electrodes changes with time. The toner is separated from the surface of the toner carrier by the electric field between the electrodes. In the developing device for forming a cloud, the adjacent pitch width between the two types of electrodes of the moving toner carrier is different.

According to a second means of the present invention, in the developing device of the first means, the toner carrier is in a roller shape.
The third means of the present invention is characterized in that in the developing device of the second means, power is supplied from the end face of the toner carrier.
According to a fourth means of the present invention, in the developing device of the second means, a power supply member is provided at the center of the roller of the toner carrier, and power is supplied from the power supply member.

According to a fifth means of the present invention, in the developing device according to any one of the first to fourth means, the surface layer of the toner carrier is coated with a material opposite to the toner in a charged series. It is characterized by that.
According to a sixth means of the present invention, in the developing device of any one of the first to fifth means, the surface layer of the toner carrier has a volume resistance of 10E7 (Ω · cm) to 10E13 (Ω · cm) of the material. (“E7” means “× 10 ⁷ ” and is abbreviated.)
Further, according to a seventh means of the present invention, in the developing device of any one of the first to sixth means, the cloud potential on the toner carrier is an image portion potential and a non-image portion potential of the electrostatic latent image. It is characterized by being between.

The eighth means of the present invention is a means for forming an electrostatic latent image on an electrostatic latent image carrier, and developing and developing the electrostatic latent image formed on the electrostatic latent image carrier. In the image forming apparatus including the developing unit, the developing unit includes any one of first to seventh developing devices.
According to a ninth means of the present invention, in the image forming apparatus of the eighth means, two or more types of toner images are superimposed on the electrostatic latent image carrier.

In the developing device of the present invention, a flare developing method capable of realizing high image quality (high resolution dot reproducibility) is used, and in the flare developing method, adjacent pitch widths between two types of electrodes of the moving toner carrier are different. By doing so, flare toner deviation can be prevented, and flare uniformity on the electrode can be improved, and thus toner scattering and image unevenness can be improved.
In the image forming apparatus of the present invention, a flare development method capable of obtaining a high-quality image with an overwhelmingly excellent dot reproducibility compared to the conventional development method is used. By providing a developing device capable of improving flare uniformity and thus improving toner scattering and image unevenness, high-quality image formation can be stably performed over a long period of time.

  Hereinafter, the configuration, operation, and effects of the present invention will be described in detail based on the illustrated embodiments.

FIG. 1 is a view showing an example of a toner carrier used in the developing device of the present invention, and is a cross-sectional view showing an enlarged part of a surface layer of a flare developing roller 31 which is a toner carrier. This toner carrier (flare developing roller) 31 is formed by forming an electrode pattern 42 on a resin roller 41 made of an insulating material (for example, PI (polyimide) resin) by vapor deposition of aluminum, and has a thickness of about 3 μm as a surface protective layer thereon. A resin coat 43 having a volume resistivity of about 10E10 Ω · cm is applied. The electrode pattern 42 is divided into two groups of electrodes 41A and 42B and is connected to a bias power source 59, which is a voltage supply means, so that the electric field between the two types of electrodes changes with time. A reverse phase voltage is supplied to the seed electrodes 42A and 42B. The adjacent pitch widths a and b between the two types of electrodes 42A and 42B of the toner carrier 31 are different (a> b). The above volume resistivity “E10” means “× 10 ¹⁰ ”, and will be similarly abbreviated in the following.

Next, FIGS. 2 to 5 are diagrams for explaining a prototype of the toner carrier.
FIG. 2 is a perspective view showing an example of the appearance of the flare developing roller 31 as a toner carrier. The flare developing roller 31 is an electrode shaft A (40A) in which an electrode group of reference numeral 42A formed on the resin roller 41 is bundled. And the electrode axis B (40A) in which the electrode group of reference numeral 42B is bundled can be rotated as a rotation axis. The configuration and manufacturing method of the toner carrier (flare developing roller) 31 will be described below.

  FIG. 3 is an explanatory diagram of the configuration of the flare developing roller 31. In this example, as shown in FIG. 3 (1), a resin roller 41 having a shaft hole 52 in a cylinder 51 made of acrylic resin (or PI resin or the like) is provided with an electrode shaft A and an electrode shaft as shown in FIG. Stainless steel electrode shafts 40A and 40B to be B are press-fitted. Next, by the steps (1) to (5) in FIG. 4, electrodes 42A and 42B having a pattern as shown in (3) in FIG. 3 are formed on the surface layer of the resin roller. Of course, it goes without saying that the pattern electrodes 42A and 42B are formed so that they can be energized with the electrode axis A (40A) and the electrode axis B (40B), respectively.

  FIG. 4 is a diagram showing the electrode pattern and surface layer manufacturing process of the flare developing roller. Each process diagram is a view when the surface layer portion of the flare developing roller as a toner carrier is viewed from the direction along the rotation axis. It is sectional drawing which expands and shows a part. In FIG. 4A, the surface of the resin roller 41 in FIG. 3B is finished smoothly by peripheral turning. In FIG. 4B, groove cutting is performed so that the groove pitch is a, b (a> b, for example, a = 130 [μm], b = 100 [μm]), and the groove width is 50 [μm]. In FIG. 4 (3), electroless nickel plating for forming the electrode 42 is applied, and in FIG. 4 (4), the outer periphery is turned to remove unnecessary conductor films. At this time, the electrodes 42A and 42B are formed in the groove portions. Thereafter, as shown in FIG. 4 (5), a resin coating 43 is applied with a silicone resin to smooth the roller surface. At the same time, the resin coating 43 is coated with a surface protective layer (thickness of about 5 [μm], volume resistance 10E10 [Ω · cm]).

  If the volume resistance of the surface protective layer 43 of the toner carrier (flare developing roller) is less than 10E7 (Ω · cm), charge leakage (short circuit) occurs between the electrode groups. The effect is not obtained and the flare activity deteriorates. On the other hand, if it is greater than 10E13 (Ω · cm), the surface of the toner carrier (flare developing roller) remains charged due to friction with the toner that repeatedly flies, and the average potential of the surface of the toner carrier (flare developing roller) Will change. Therefore, it is desirable that the surface layer of the toner carrier (flare developing roller) has a volume resistance of 10E7 (Ω · cm) to 10E13 (Ω · cm). If the charge series of the resin coat layer is made to have the same polarity as that of the toner, the charge amount of the flared toner gradually decreases, and flare activity deteriorates. Therefore, in the present invention, the surface layer of the toner carrying member is configured to be coated (resin coated) with the material on the opposite side of the charging series with respect to the toner. In this way, the charge amount of the flared toner can be maintained by reversing the toner and the charge series.

FIG. 5 shows a method of applying a voltage to the electrode shaft A and the electrode shaft B of the toner carrier (flare developing roller).
In the case of the example of FIG. 5A, power is supplied by bringing a conductive member such as an electrode plate or a conductive brush into contact with the roller end surface or the power supply surface on the surface.
In the case of the example in FIG. 2 (2), a power supply member such as an electrode plate or a conductive brush is brought into contact with the power supply surfaces of the electrode shaft A (40A) and the electrode shaft B (40B). To do. This configuration can be connected to the image forming engine side with a simple configuration and can supply power.
FIG. 3C shows an example of the bias applied to the electrode axis A and the electrode axis B. Here, a rectangular wave AC voltage having a frequency of 0.5 to 2.0 [kHz] and a peak-to-peak voltage: Vpp = 200 to 400 [V] is applied. A bias is applied to the electrode axis A and the electrode axis B so as to have the same frequency, the same Vpp, and opposite phases. By applying such a bias, the charged toner enters a hopping state and forms a toner cloud (referred to as flare).
By adopting the above-described configuration, it is possible to stably apply two types of voltages (same frequency, same Vpp and opposite phase bias voltages) to the electrodes 42A and 42B of the toner carrier (flare developing roller) 31. .

  Here, the concept of how the flare toner moves when the adjacent pitch widths between the comb electrodes are equal will be described with reference to FIG. Here, for simplification, the bias is switched only by the A-phase electrode, and the B-phase electrode is grounded to GND. Therefore, each time the bias applied to the A-phase electrode is switched, the toner on one electrode receives an equal force from the electric field formed between that electrode and both adjacent electrodes.

  In the diagram on the left side of FIG. 6, the negatively charged toner existing on the B-phase electrode exerts a force from the same electric field on the left and right sides of the A-phase electrodes on both sides of the pitch distance a where the bias is switched to + 200V. In response, it moves onto the A-phase electrode with equal probability to the left and right. Thereafter, the negatively charged toner on the A-phase electrode is switched from the same electric field to the left and right B-phase electrodes as shown in the right side of FIG. 6 by switching the A-phase electrode to −200V bias. The toner moves onto the B-phase electrode with equal probability to the left and right. Then, by repeating this operation according to the bias switching frequency, flare (toner cloud) occurs.

However, there may be a phenomenon (flare toner side) in which flare toner gradually moves in a certain direction due to variations in electrode shape, pitch a between electrodes, slight external force such as gravity and airflow, and the like.
When the flare toner is near, the electrostatic latent image carrier may be scattered due to scattering at the portion where the toner is gathered, flare cloud bias variation due to flare toner, or toner amount variation on the toner carrier. It has been found that there is a case where the developed toner adhesion amount varies, resulting in image unevenness lacking in uniformity.

Therefore, in the present invention, as shown in FIG. 7, it has been found that the adjacent pitch widths between the electrodes are different as a and b.
The idea of how the flare toner moves in this case will be described with reference to FIG. Here, as in the case of FIG. 6, the bias is switched only by the A-phase electrode for simplification, and the B-phase electrode is grounded to GND. Therefore, each time the bias applied to the A-phase electrode is switched, the toner on an electrode receives a force from an electric field of a different magnitude formed between that electrode and both adjacent electrodes.

  In the diagram on the left side of FIG. 7, the negatively charged toner existing on the B-phase electrode is adjacent to the right-side A-phase electrode at the pitch distance b where the bias is switched to +200 V, and the pitch distance a (b <a). Receiving a force from an electric field of a different magnitude from the left and right, and the probability that the force from the electric field moves to the right A-phase electrode at a pitch distance b is large. . After that, the negatively charged toner on the A-phase electrode is switched to the B-phase electrode adjacent to the left of the pitch distance b as shown in the right side of FIG. On the left B-phase electrode having a distance b between the pitches where the force from the electric field is large due to the force from the electric field of different magnitude from the left and right with the B-phase electrode adjacent to the right of the distance a (b <a) The probability of moving to is increased. Then, by repeating this operation according to the bias switching frequency, flare occurs.

  In the case of this electrode configuration, the direction in which the toner is moved is determined every time the bias is switched even if there are variations in the electrode shape, variations in the pitches a and b between the electrodes, and a slight external force such as gravity and airflow. Therefore, it was found effective against flare toner.

FIG. 8 shows the result of evaluating the flare toner side when the B-phase electrode is grounded to GND and a bias of 0 ± 400 [V] and frequency 1 [kHz] is applied to the A-phase electrode. In this evaluation experiment, a flare developing roller 31 having a pattern electrode as described with reference to FIGS. 1 to 3 was used as a toner carrier, and toner was placed on the flare developing roller at 0.5 mg / cm ² and 25 cm. Put evenly on ² areas. Then, the state of the flare toner after the bias is applied for 3 seconds is observed, and the flare rank is set. In FIG. 8, rank 5: no shift, rank 4: acceptable level, rank 3 or lower: NG.

The movement time from the toner supply unit to the development unit on the flare developing roller is 0.5 seconds at most, and 3 seconds is a sufficient time to confirm the toner shift. Temporarily, the linear velocity of the electrostatic latent image carrier (for example, organic photoreceptor (OPC)) is 150 [mm / sec], the linear velocity ratio of the flare developing roller to OPC is 1/2, and the flare developing roller diameter is φ18 [mm. Even if it is assumed that the supply to development is 180 °, the moving time is 0.38 seconds.
As parameters, the pitch b is 40 [μm] and 60 [μm], and the pitch a is 40 [μm], 60 [μm], 80 [μm], 100 [μm], 120 [μm], and 140 [μm]. ], 160 [μm], 180 [μm], and 200 [μm].

  From this, it has been clarified that, with respect to the equidistant electrode pitch of a = b, the adjacent pitch interval of a> b is more advantageous to the toner. However, if a is too large with respect to b, the rank tends to deteriorate. This is considered to be due to the fact that the flare activity was weakened because the electric field between the electrodes was too weak due to the pitch being too wide, unlike the previous toner. This can be dealt with by increasing the applied bias Vpp.

Next, FIGS. 9 to 11 are views showing an embodiment of a developing device using a flare developing roller 31 which is a toner carrier of the present invention.
The embodiment shown in FIG. 9 is a schematic configuration diagram of a developing device using the toner carrier (flare developing roller) 31. The flare developing roller 31 that is a toner carrier is in contact with the spikes of the two-component developer by a normal two-component developer 56. Specifically, in the container 60 of the two-component developing device 56, the magnetic carrier powder having a particle size of 35 [μm] and the polyester toner having a particle size of about 6 [μm] are mixed at a weight ratio of 7 by the stirring and conveying members 61 and 62. The two-component developer 63 mixed with ˜8 [wt%] is conveyed to the toner carrier (flare developing roller) 31 by the magnet sleeve 57 containing the permanent magnet of the two-component developer 56, where a part of the toner is transferred. The toner is transferred to the toner carrier (flare developing roller) 31 by a DC bias potential applied between the magnet sleeve 57 and the toner carrier (flare developing roller) 31. The toner transferred to the toner carrier (flare developing roller) 31 is rotated and driven by a drive unit (not shown) while forming a flare on the toner carrier (flare developing roller) 31. As a result, the toner is conveyed to a portion opposite to the electrostatic latent image carrier 58, and the toner is electrostatic latent depending on the difference between the average potential of the surface of the toner carrier (flare developing roller) 31 and the potential of the electrostatic latent image carrier 58. By adhering to the electrostatic latent image on the image carrier 58, the electrostatic latent image is developed to form a toner image. Note that an AC voltage is applied as a bias potential from an AC bias power source 59 by an electrode brush or the like between the electrode shafts 40A and 40B of the toner carrier (flare developing roller) 31 described above, and an electrode group 42A connected to the electrode shaft 40A. And a time-periodic potential difference is formed between the electrode group 42B connected to the electrode shaft 40B.

Note that unnecessary toner that has not contributed to the development returns to the magnetic sleeve 57 from the developing portion again. Since flare is formed on the toner carrying member (flare developing roller) 31, the adhesion force of the toner to the toner carrying member (flare developing roller) 31 is very low. The toner returned from is easily scraped or acclimatized by the spikes of the two-component developer following the rotation of the magnet sleeve 57. By repeating this, a substantially constant amount of toner flare is always formed on the toner carrier (flare developing roller) 31.
The two-component developing device 56 conveys and circulates the two-component developer 63 in the container 60 with stirring by the stirring and conveying members 61 and 62, and the magnet sleeve 57 circulates a part of the two-component developer in the toner carrier ( A flare developing roller) 31 is transported and unnecessary toner that has not contributed to development is returned from the developing unit.

  FIG. 10 is a diagram showing another embodiment of the present invention, and is a schematic configuration diagram of a developing device using a flare developing roller. In this embodiment, the two-component developing device 56 is simplified by omitting the magnet sleeve 57 from the embodiment shown in FIG. 9, and supplies toner to the toner carrier (flare developing roller) 31 in two components. This is performed by the cascade development phenomenon of the developer 63. Since the two-component developer 56 forms a thin toner layer on the toner carrier (flare developing roller) 31 using a simple cascade, the toner transfer rate to the toner carrier (flare developing roller) 31 is shown in FIG. Although it is lower than that of the embodiment, by increasing the rotational speed of the toner carrier (flare developing roller) 31 correspondingly, it is possible to cope with the development speed of the electrostatic latent image carrier 58.

FIG. 11 is a view showing still another embodiment of the present invention, and is a schematic configuration diagram of a developing device using a flare developing roller. In this embodiment, instead of the two-component developing device 56, a one-component developing device 64 having only the toner 66 in the container 65 is used, and this one-component developing device 64 is used with respect to the toner carrier (flare developing roller) 31. Then, the toner is transferred to form a thin toner layer on the toner carrier (flare developing roller) 31. In this case, the one-component developing device 64 supplies the toner 66 in the container 65 to the toner carrying member (flare developing roller) 31 while being stirred and circulated by the circulation paddle 67, and on the toner carrying member (flare developing roller) 31. The toner is regulated to a constant toner amount of 0.45 [mg / cm ² ] by a doctor blade 68 as a toner regulating member to form a thin layer. Further, by applying an AC voltage to the doctor blade 68, it is possible to increase the flare activity and send it to the development area.

  In the development region, the dark portion potential of the electrostatic latent image carrier 58 is −260 [V], and the average potential of −150 [V] on the surface of the toner carrier (flare developing roller) 31 is equal to the electrostatic latent image carrier 58. A toner image is formed by the difference from the image portion potential of −40 [V], and unnecessary toner that has not contributed to development returns to the toner reservoir portion again. Since the flare is formed, the adhesion force of the toner to the toner carrier (flare developing roller) 31 is very low, and the toner returned from the developing unit by the toner carrier (flare developing roller) 31 is in the toner reservoir. The toner is easily scraped or habituated by rubbing between the toners. By repeating this, a substantially constant amount of toner flare is always formed on the toner carrier (flare developing roller) 31.

Next, FIG. 12 is a schematic configuration diagram of an essential part showing an example of an image forming apparatus configured by using a plurality of developing devices having substantially the same configuration as FIG.
In this embodiment, image formation is provided with developing devices 73K, 73Y, 73C, 73M configured to supply the toner 66 in the container 65 to the toner carrier (flare developing roller) 31 while being circulated by stirring with a circulation paddle 67. The units 70K, 70Y, 70C, and 70M are arranged side by side along a belt-like photoconductor 69 that is an electrostatic latent image carrier, and a developing device 73K of four image forming units 70K, 70Y, 70C, and 70M. , 73Y, 73C, and 73M, toners 66 of black (K), yellow (Y), cyan (C), and magenta (M) are stored. In FIG. 12, reference numerals 71K, 71Y, 71C, and 71M denote charging devices for charging the photosensitive member, and 72K, 72Y, 72C, and 72M denote writing devices (for example, a laser light source, an optical deflector, and a scanning imaging optical system). Writing light (electrostatic latent image forming means) from the optical scanning system writing device, etc., 74K, 74Y, and 74C are static eliminating devices that neutralize the photosensitive member, and 75 is an image on the photosensitive member such as recording paper. A transfer device for transferring to the transfer material, 76 a fixing device for fixing the toner image transferred to the transfer material, and 77 a cleaning device for cleaning the toner remaining on the photoconductor 69 after the transfer.

  This image forming apparatus includes four image forming units 70K, 70Y, 70C, and 70M for a belt-shaped photoconductor 69, charging by charging devices 71K, 71Y, 71C, and 71M, and writing light 72K from a writing device. A system for forming a latent image by 72Y, 72C, 72M, developing with each color toner of developing devices 73K, 73Y, 73C, 73M, and forming a color image by sequentially superimposing toner images of each color on photoreceptor 69. It is an example. By adopting such a system, writing and development for four colors are performed on the same photosensitive member 69, so that an ordinary four-tandem image forming apparatus (for example, a drum-shaped photosensitive member and a charging unit, In comparison with an image forming apparatus having a configuration in which four image forming units each having a developing unit, a writing unit, and a cleaning unit are arranged side by side along an intermediate transfer belt or a transfer material conveying belt), in principle, the image is misaligned. There is an advantage that it hardly occurs. Further, by using the developing device according to the present invention, there is no influence on the toner image once formed on the photosensitive member, so there is no problem such as scavenging or color mixing, and high-quality image formation is possible. The process can be performed stably over a long period of time.

It is a figure which shows an example of the toner carrier used for the developing device of this invention, and is sectional drawing which expands and shows a part of surface layer of the flare developing roller which is a toner carrier. FIG. 3 is a perspective view illustrating an example of an appearance of a flare developing roller that is a toner carrier. FIG. 4 is a configuration explanatory diagram of a flare developing roller. It is a figure which shows the preparation process of the electrode pattern and surface layer of a flare developing roller. It is a figure which shows the application method of the voltage to the electrode shaft A and electrode shaft B of a flare developing roller. It is a figure for demonstrating the thought of how a flare toner moves when the adjacent pitch width between comb-tooth electrodes is equal. It is a figure for demonstrating the thought of how the flare toner moves when the adjacent pitch width between comb-tooth electrodes differs. It is a figure which shows the result of having evaluated the toner side of the flare when the B-phase electrode of the flare developing roller is grounded to GND and a predetermined bias is applied to the A-phase electrode. 1 is a diagram illustrating an embodiment of the present invention, and is a schematic configuration diagram of a developing device using a flare developing roller. It is a figure which shows another Example of this invention, and is a schematic block diagram of the image development apparatus using a flare developing roller. It is a figure which shows another Example of this invention, and is a schematic block diagram of the image development apparatus using a flare developing roller. FIG. 3 is a schematic configuration diagram of an essential part showing an example of an image forming apparatus configured by using a plurality of developing devices using flare developing rollers.

Explanation of symbols

31: Toner carrier (flare developing roller)
40A: Electrode axis A
40B: Electrode axis B
41: Resin roller 42: Electrode 42A: A phase electrode 42B: B phase electrode 43: Resin coat (surface protective layer)
56: Two-component developer 57: Magnet sleeve 58: Electrostatic latent image carrier 59: Bias power supply 60: Container 61, 62: Stirring conveyance member 63: Two-component developer 64: 1 Component developer 65: Container 66: Toner 67: Circulating paddle 68: Doctor blade 69: Photoconductor (electrostatic latent image carrier)
70K, 70Y, 70C, 70M: image forming units 71K, 71Y, 71C, 71M: charging devices 72K, 72Y, 72C, 72M: writing light (electrostatic latent image forming means)
73K, 73Y, 73C, 73M: Developing device 74K, 74Y, 74C: Static eliminating device 75: Transfer device 76: Fixing device 77: Cleaning device

Claims (9)

A developing device having a toner carrier that is disposed to face an electrostatic latent image carrier and moves while carrying toner for developing the electrostatic latent image formed on the electrostatic latent image carrier. In addition, the toner carrier has a surface layer, and two types and each of them has a non-conductive electrode pattern in the lower layer of the surface layer, an insulating layer in the lower layer of the electrode pattern, and a gap between the two types of electrodes. In a developing device that includes voltage supply means for supplying a voltage to the electrodes so that the electric field changes with time, and forms the cloud by separating the toner from the surface of the toner carrier by the electric field between the electrodes,
2. A developing device according to claim 1, wherein the moving toner carrier has different adjacent pitch widths between the two kinds of electrodes. The developing device according to claim 1,
2. A developing device according to claim 1, wherein the toner carrier has a roller shape. The developing device according to claim 2, wherein
A developing device, wherein power is supplied from an end surface of the toner carrier. The developing device according to claim 2, wherein
A developing device having a power supply member at the center of a roller of the toner carrier, and supplying power from the power supply member. In the developing device according to any one of claims 1 to 4,
2. A developing device according to claim 1, wherein a surface layer of the toner carrying member is covered with a material opposite to the toner in a charging series. In the developing device according to any one of claims 1 to 5,
A developing device, wherein a surface layer of the toner carrier is coated with a material having a volume resistance of 10E7 (Ω · cm) to 10E13 (Ω · cm). In the developing device according to any one of claims 1 to 6,
A developing device, wherein a cloud potential on the toner carrier is between an image portion potential and a non-image portion potential of the electrostatic latent image. Image forming apparatus comprising means for forming an electrostatic latent image on an electrostatic latent image carrier and developing means for developing and developing the electrostatic latent image formed on the electrostatic latent image carrier In
An image forming apparatus comprising the developing device according to claim 1 as the developing unit. The image forming apparatus according to claim 8.
An image forming apparatus, wherein two or more types of toner images are superimposed on the electrostatic latent image carrier.

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