JP2010044167A - Developing device, image forming apparatus, and process cartridge - Google Patents

Abstract

In a flare development system, fluctuations in the surface potential of a toner carrier are suppressed to prevent image density unevenness and background smearing.
[Solution]
A flare roller 61 having a plurality of electrodes arranged in a predetermined direction and an insulating surface protective layer, a supply roller 62 for supplying toner to the flare roller, and electrodes adjacent to each other in the flare roller change with time in a predetermined cycle. A development having a power source for applying a voltage and a regulating member 73 for regulating the thickness of the toner on the flare roller, and transporting the toner to the development position with the rotation of the flare roller while developing the toner on the flare roller. In the apparatus 4, a conductive contact member 71 that contacts the surface of the flare roller is provided downstream of the development position and upstream of the regulating member, and the same average value as the average value of the voltage applied to the electrode of the flare roller Is applied to the conductive contact member.
[Selection] Figure 2

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus such as a copying machine, a printer, and a facsimile machine that forms an image using the developing device.

  2. Description of the Related Art Conventionally, as a developing device, a toner that is hopped on the surface of a toner carrier such as a toner transport substrate is used for development, instead of using toner adsorbed on a developing roller or a magnetic carrier for development. .

  For example, the developing device described in Patent Document 1 has a cylindrical toner carrier having a plurality of electrodes arranged at a predetermined pitch in the circumferential direction. These electrodes are formed by repeatedly arranging electrode pairs composed of two electrodes adjacent to each other, and an oscillating electric field is formed between the two electrodes in each electrode pair. Due to this oscillating electric field, the toner located on one electrode in the electrode pair floats and landes on the other electrode, or floats on the other electrode and landes on one electrode. Or In this way, the toner is transported to the developing position facing the latent image carrier as the cylindrical toner carrier rotates while repeating reciprocating movement by hopping between the two electrodes. At the development position, the toner that has hopped from the surface of the toner carrying member and floated to the vicinity on the latent image carrying member is attracted to the electric field by the latent image and adheres to the latent image. By this adhesion, the latent image is developed into a toner image. Such development is called a flare development method, and low potential development can be realized by using toner released from the adhesion to the surface of the toner carrier by hopping. For example, toner can be selectively attached to an electrostatic latent image having a potential difference of only a few tens [V] with respect to surrounding non-image portions.

JP 2007-133390 A

  In the flare developing type developing device, an insulating surface protective layer is provided on the surface of the toner carrier to protect the electrode. Further, in order to prevent image density unevenness due to toner thickness unevenness on the toner carrier, a regulating member for regulating the toner thickness on the toner carrier is provided. Further, there is also a toner supply unit that supplies toner to the toner carrying member, by applying a voltage that forms an electric field that moves the toner from the toner supply unit to the toner carrying member, thereby improving the toner supply efficiency. With such a configuration, when the toner carrier is rotated, friction charging between the regulating member and the toner carrier surface protective layer, frictional charging between the toner itself to be hopped and the toner carrier surface protective layer, toner supply means and toner carrier Charge is gradually accumulated on the surface protective layer on the surface of the toner carrier due to frictional charging with the surface protective layer of the body and injection of charge into the surface of the toner carrier by the voltage applied to the toner supply means. It was found that the potential fluctuated greatly. If the surface potential of the toner carrier greatly fluctuates, the potential difference between the surface of the toner carrier and the latent image carrier fluctuates at the portion facing the latent image carrier, which causes image density unevenness, background stains, and the like. End up.

  The present invention has been made in view of the above problems, and an object of the present invention is to perform flare development capable of suppressing fluctuations in the surface potential of a toner carrier and preventing unevenness in image density and background staining. The present invention provides a developing device, a process cartridge, and an image forming apparatus that employ a method.

In order to achieve the above object, the invention according to claim 1 is directed to a toner carrier including a plurality of electrodes arranged in a predetermined direction, an insulating surface protective layer for protecting the electrodes, and a surface of the toner carrier. At least some of the electrodes are predetermined so as to form an oscillating electric field such that the toner repeatedly reciprocates by hopping between the toner supply means for supplying the toner and the electrodes adjacent to each other among the plurality of electrodes of the toner carrier. An electrode voltage applying means for applying a voltage that changes with time in a period of time, and a toner thickness regulating position by a regulating member as the surface of the toner carrier is moved while hopping the toner on the surface of the toner carrier. In the developing device for transporting the toner image to the developing position that is opposite to the latent image carrier and attaching it to the latent image on the latent image carrier, in the direction of surface movement of the toner carrier A conductive contact member arranged to contact the surface of the toner carrier downstream of the developing position and upstream of the regulating member, and a contact member voltage for applying a voltage to the contact member And the average value of the voltage applied to the contact member by the contact member voltage application means is the same as the average value of the voltage applied to the electrode of the toner carrier by the electrode voltage application means. It is characterized by being.
According to a second aspect of the present invention, in the developing device of the first aspect, the voltage applied to one electrode group of the adjacent electrodes of the toner carrier and the other electrode group are applied by the electrode voltage applying means. The voltage is a voltage having a waveform that changes in time opposite in phase to each other, and the voltage applied to the contact member by the contact member voltage applying means is a DC voltage.
According to a third aspect of the present invention, in the developing device of the first aspect, a voltage having a waveform in which a voltage applied to one electrode group among adjacent electrodes of the toner carrier by the electrode voltage applying unit changes with time. The voltage applied to the other electrode group is a DC voltage, and the voltage applied to the contact member by the contact member voltage applying means is a DC voltage.
According to a fourth aspect of the present invention, in the developing device according to the first aspect, the voltage applied to one electrode group among the adjacent electrodes of the toner carrier and the other electrode group are applied by the electrode voltage applying means. The voltage is a voltage having a waveform that changes in time opposite in phase, and the voltage applied to the contact member by the contact member voltage applying means is a voltage having a waveform that changes in time. It is what.
According to a fifth aspect of the present invention, in the developing device according to the fourth aspect, the voltage applied to the contact member by the contact member voltage application means is the one electrode group or the other applied by the electrode voltage application means. The voltage applied to any one of the electrode groups is the same.
According to a sixth aspect of the present invention, in the developing device according to the first aspect, the voltage applied to one of the adjacent electrodes of the toner carrier by the electrode voltage applying means has a waveform voltage that changes with time. And the voltage applied to the other electrode group is a DC voltage, and the voltage applied to the contact member by the contact member voltage applying means is applied to the one electrode group over time. It is characterized by the same voltage as
According to a seventh aspect of the present invention, in the developing device according to any one of the first to sixth aspects, the contact member is a non-woven fabric.
The invention according to claim 8 is the developing apparatus according to any one of claims 1 to 6, wherein the contact member is an elastic body.
According to a ninth aspect of the present invention, in the developing device according to any one of the first to sixth aspects, the contact member is a foam.
According to a tenth aspect of the present invention, in the developing device according to any one of the first to sixth aspects, the contact member is a fur brush.
The invention according to claim 11 is the developing device according to any one of claims 1 to 6, wherein the contact member is a cylindrical roller.
According to a twelfth aspect of the present invention, in the developing device of the eleventh aspect, the cylindrical roller also has a function as a toner supply means for supplying toner to the toner carrier.
According to a thirteenth aspect of the present invention, there is provided a latent image carrier, latent image forming means for forming an electrostatic latent image on the latent image carrier, and an electrostatic latent image formed on the latent image carrier. An image forming apparatus including a developing unit for developing employs the developing device according to any one of claims 1 to 12 as the developing unit.
According to a fourteenth aspect of the present invention, in the image forming apparatus according to the thirteenth aspect, a plurality of the developing devices are provided, development is performed by a plurality of developing devices, and images are superimposed on the latent image carrier to form a multicolor image. It is characterized by forming.
The invention according to claim 15 is the image forming apparatus according to claim 13 or 14, wherein at least one of the latent image carrier, the charging means, and the cleaning means and the developing means are integrally held and can be detached from the main body. It is characterized by having a process cartridge.
According to a sixteenth aspect of the present invention, there is provided a process cartridge in which at least one of the latent image carrier, the charging unit, and the cleaning unit and the developing unit are integrally held, and the developing unit is detachable from the main body of the image forming apparatus. The developing device according to any one of claims 1 to 12 is employed.

  In the present invention, the surface potential of the toner carrier is brought into contact with the surface of the toner carrier by a conductive contact member to which a voltage having the same average value as the voltage applied to the electrode of the toner carrier is applied. Can be maintained constant. When a voltage having an average value different from the average value of the voltage applied to the electrode of the toner carrier is applied to the conductive contact member, the charge of the difference between the average values is generated in the insulating surface protective layer of the toner carrier. Since the surface potential becomes constant after accumulation, the surface potential of the toner carrying member fluctuates.

  As described above, according to the present invention, there is provided a developing device, a process cartridge, and an image forming apparatus that employ a flare developing system capable of suppressing fluctuations in the surface potential of a toner carrier and preventing image density unevenness and background smearing. There is an excellent effect that it can be provided.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic image forming apparatus will be described. First, the configuration and operation of the image forming apparatus according to the present embodiment will be described.
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment. This image forming apparatus is an image forming apparatus that has a plurality of developing devices and forms a multicolor image by superimposing toner images of respective colors on a belt-like photoreceptor 1 as a latent image carrier. The belt-like photoreceptor 1 is rotationally driven in a clockwise direction in the figure by a driving unit (not shown) while being stretched around a plurality of rollers in a vertically long posture with a space in the vertical direction rather than the horizontal direction. The left tension surface in the figure (hereinafter referred to as the left tension surface) of the photosensitive member 1 is in a posture extending substantially in the vertical direction.

  On the left side of the left-side stretched surface of the photoreceptor 1, images of a plurality of colors, for example, magenta (M), cyan (C), yellow (Y), and black (K) are provided so as to face the photoreceptor 1. Four process units 6M, 6C, 6Y, and 6K are arranged in the vertical direction as a plurality of image forming units to be formed. These four process units 6M, 6C, 6Y, and 6K respectively include developing devices 4M, C, Y, and K, charging devices 2M, C, Y, and K for uniformly charging the photosensitive member 1, and a static eliminator (not shown). Are held in a common holding body (not shown) as one unit. The developing devices 4M, C, Y, and K, the charging devices 2M, C, Y, and K and the static eliminator are integrally attached to and detached from the housing of the image forming apparatus as process units 6M, C, Y and K, respectively. Can be exchanged by the user.

  Further, between the charging devices 2M, C, Y, and K and the developing devices 4M, C, Y, and K of the process units 6M, C, Y, and K, exposure beams 3M of respective colors by an optical writing device (not shown) are provided. , C, Y, K are provided. Furthermore, a transfer unit (not shown), a cleaning unit, a paper feeding device, a fixing device, and the like are provided.

The photosensitive member 1 is rotationally driven in the direction of the arrow in FIG. 1, uniformly charged by a magenta charging unit 2M in a magenta process unit 6M, and then modulated by magenta image data by an optical writing device (not shown). An electrostatic latent image is formed by exposure with the beam 3M. The electrostatic latent image is developed by the magenta developing device 4M to become a magenta toner image. Thereafter, the photosensitive member 1 is neutralized by a static eliminator (not shown) to prepare for the next cyan image formation.
Next, the photosensitive member 1 is uniformly charged by a cyan charging unit 2C in a cyan process unit 6C, and then exposed by an exposure beam 3C modulated by cyan image data by an optical writing device (not shown). As a result, an electrostatic latent image is formed. The electrostatic latent image is developed by the cyan developing device 4C to become a cyan toner image overlapping the magenta toner image. Thereafter, the photoreceptor 1 is neutralized by a static eliminator (not shown) to prepare for the next color image formation.
Further, the photoreceptor 1 is uniformly charged by the yellow charging device 2Y in the yellow process unit 6Y, and then exposed by the exposure beam 3Y modulated by the yellow image data by an optical writing device (not shown). As a result, an electrostatic latent image is formed. The electrostatic latent image is developed by the yellow developing device 4Y to become a yellow toner image overlapping the magenta toner image and the cyan toner image. Thereafter, the photoreceptor 1 is neutralized by a static eliminator (not shown) to prepare for the next color image formation.
Finally, the photoreceptor 1 is uniformly charged by the black charging device 2K in the black process unit 6K, and then exposed by the exposure beam 3K modulated by the black image data by the optical writing device (not shown). Thus, an electrostatic latent image is formed. The electrostatic latent image is developed by the black developing device 4K to form a black toner image overlapping the magenta toner image, the cyan toner image, and the yellow toner image, thereby forming a full color image.

  On the other hand, a recording medium such as recording paper is fed from a paper feeding device (not shown), and a full color image on the photosensitive member 1 is transferred to the recording medium by a transfer roller as a transfer unit to which a transfer bias is applied. The recording medium on which the full-color image is transferred is fixed by the fixing device (not shown) and discharged to the outside. Residual toner and the like are removed from the photoreceptor 1 by a cleaning unit (not shown) after the transfer of the full-color image.

  In the image forming apparatus having such a configuration, four colors are written on the same photoconductor 1, and therefore, in principle, there is almost no positional deviation as compared with the normal quadruple tandem system. In this way, it is possible to obtain a high-quality full-color image without color misalignment.

  Next, the developing device employed in the image forming apparatus of the present embodiment will be described. The developing devices 4M, C, Y, and K have the same configuration and operation except that the toners to be stored are different. Therefore, the subscripts M, C, Y, and K will be omitted below.

  FIG. 2 is a schematic configuration diagram of the developing device 4. The toner carrier of the developing device 4 includes a plurality of electrodes, and carries the toner in a state where the toner is hopped by an electric field formed between adjacent electrodes. A so-called flare development method is adopted in which the development is carried to a developing position which is a facing portion. The cylindrical toner carrier used for the development of this flare development system is hereinafter referred to as a flare roller.

  The developing device 4 includes a casing 70 that forms a toner accommodating portion that accommodates toner to be supplied to the photosensitive member 1, a flare roller 61 that is a toner carrier facing the photosensitive member 1 at an opening of the casing 70, and a toner accommodating portion. And a paddle 64 that pumps up the toner to the supply roller 62 while stirring the toner in the toner container. The flare roller 61, the supply roller 62, and the paddle 64 are rotated by a rotation drive mechanism (not shown). A blade-like regulating member 63 that regulates the amount of toner on the flare roller 61 is provided upstream of the flare roller 61 in the toner conveyance direction with respect to the development position. In addition, a toner leakage prevention member 65 that suppresses the leakage of toner in the casing 70 is provided at the inlet of the casing 70 on the downstream side in the toner conveyance direction of the flare roller 61 with respect to the development position.

  In the developing device 64, the toner accommodated in the toner accommodating portion is conveyed to the supply roller 62 by the rotation of the paddle 64, and is supplied to the flare roller 61 by the rotation of the supply roller 62. In order to improve toner supply efficiency to the flare roller 61, it is preferable to apply a supply voltage to the supply roller 62. When supplied to the flare roller 61, the toner is triboelectrically charged and carried in a hopped state as will be described later. Thereafter, the toner is carried along with the rotation of the flare roller 61, and the amount of adhesion is regulated by the regulating member 63. The restricting member 63 is in contact with the flare roller 61 with an insulating rubber blade, and the friction between the flare roller 61 or the restricting member 63 and the toner when passing through the contact portion between the restricting member 63 and the flare roller 61. As a result, the toner is further charged. The toner whose adhesion amount is regulated is transported to the developing position while being uniformly rearranged while hopping, and develops the electrostatic latent image on the photoreceptor 1 in a non-contact manner.

  On the other hand, unnecessary toner that has not contributed to development passes through the contact area with the toner leakage prevention member 65 and is carried to the area facing the collection roller 62. Since the toner on the flare roller 61 is hopped, the adhesion force between the flare roller 61 and the toner is very low, and the toner is easily collected by rotating the supply roller 62 in the counter direction with the flare roller 61. In the region facing the supply roller 62, new toner is supplied again to the flare roller 61. By repeating this, a state where a constant amount of toner is always hopping is formed on the flare roller 61.

  The regulating member 63 is not limited to the blade-shaped member, and a roller-shaped member may be brought into contact with the flare roller 61. In the developing device 4, the supply roller 62 also functions as a collecting unit that collects toner from the flare roller 61 after passing through the developing position. Of course, the supply roller 62 may not also serve as a collecting unit, and a collecting unit may be provided separately.

Here, the flare development method will be described in detail.
FIG. 3 is a perspective view showing a schematic configuration of the flare roller 61. The flare roller 61 has a plurality of electrodes 66 that extend in the roller axial direction and are arranged at a predetermined pitch in the roller circumferential direction on the circumferential surface of the roller portion. More specifically, the plurality of electrodes 66 are formed by alternately arranging two-phase A-phase electrodes 66a and B-phase electrodes 66b in the roller circumferential direction. FIG. 4 is a plan development view of the electrode portion of the flare roller 61.

  As shown in FIGS. 3 and 4, an A-phase common electrode 67a is provided at one end in the axial direction of the roller portion of the flare roller 61 so as to extend over the entire circumference of the roller portion. Is connected to one end of each of the plurality of A-phase electrodes 66a. Further, a B-phase common electrode 67b is provided at the other end of the roller portion in the axial direction so as to extend over the entire circumference of the roller portion, and this includes the other ends of the plurality of B-phase electrodes 66b. Each part is connected.

  FIG. 5 is an enlarged sectional view in the circumferential direction of the electrode portion of the flare roller 61. For convenience, although not shown in FIGS. 3 and 4, a plurality of A-phase electrodes 66a and B-phase electrodes 66b are arranged on the support substrate 69 at a predetermined interval, and are formed of an inorganic or organic insulating material thereon. A surface protective layer 68 is laminated, and the contact between the electrode 66 and the toner is avoided by the surface protective layer 68. In FIG. 5, lines extending from the respective A-phase electrodes 66a and B-phase electrodes 66b represent conductive lines for applying a voltage to the respective electrodes, and are indicated by black circles in the overlapping portions of the respective conductive lines. Only the parts are electrically connected and the other parts are electrically insulated. Each A-phase electrode 66a and each B-phase electrode 66b are different from each other in two phases from the A-phase flare roller power source 24a and the B-phase flare roller power source 24b, which are flare roller power sources 24 also received on the main body side. A voltage is applied.

  An A-phase brush contact member (not shown) fixed to the casing 70 rubs against the A-phase common electrode 67a that moves endlessly on the rotation track as the flare roller 61 rotates. The A-phase pulse voltage output from the A-phase flare roller power source 24a shown in FIGS. 3 and 5 is applied to each A-phase electrode 66a via the A-phase brush contact member and the A-phase common electrode 67a. Applied. In addition, a B-phase brush contact member (not shown) fixed to the casing rubs against the B-phase common electrode 67b that moves endlessly on the rotation track as the flare roller 61 rotates. The B-phase pulse voltage output from the B-phase flare roller power supply 24b is applied to each B-phase electrode 66b via the B-phase brush contact member and the B-phase common electrode 67b.

  Hereinafter, a set of a plurality of A-phase electrodes 66a to which the A-phase pulse voltage is applied is referred to as an A-phase electrode group 66A. A set of a plurality of B-phase electrodes 66b to which a B-phase pulse voltage is applied is referred to as a B-phase electrode group 66B. Since the A-phase electrodes 66a and the B-phase electrodes 66b are alternately arranged, the order of arrangement of the plurality of A-phase electrodes 66a from the predetermined position in the roller circumferential direction is odd or even. The arrangement order of the plurality of B-phase electrodes 66b is even when the arrangement order of the A-phase electrodes 66a is odd, and is even when the arrangement order of the A-phase electrodes 66a is even. .

FIG. 6B shows an example of two different voltages applied to the A-phase electrode group 66A from the A-phase flare roller power supply 24a and to the B-phase electrode group 66B from the B-phase flare roller power supply 24b. To the A-phase electrode group 66A, for example, a rectangular-wave A-phase pulse voltage Va that repeats rising and falling at a predetermined cycle as shown in FIG. 6B is applied. On the other hand, the B-phase electrode group 66B is applied with a rectangular B-phase pulse voltage Vb whose rising and falling phases are opposite to the A-phase pulse voltage Vb. The period T, frequency f (f = 1 / T), peak-to-peak voltage Vpp, and amplitude center potential Vc of each pulse voltage are the same. When such a pulse voltage is applied, the toner on the flare roller 61 floats from directly above the A-phase electrode 66a and lands on the adjacent B-phase electrode 66b so as to draw a parabola, The reciprocating movement by hopping is repeated such that it floats right above the B-phase electrode 66b and returns to the adjacent A-phase electrode 66a so as to draw a parabola.
Thus, the flare roller power supply 24 (24a, 24b) is an electrode voltage application means for applying a voltage so that the electric field between the plurality of electrodes (A-phase electrode 66a, B-phase electrode 66b) changes with time. is there.

  As described above, the toner that repeats reciprocating movement by hopping in this way is conveyed to the developing position by the rotational drive of the flare roller 61. At the development position, the toner that has reached the vicinity of the electrostatic latent image on the photosensitive member 1 near the apex of the parabolic hopping locus deviates from the hopping locus while being pulled by the electrostatic force of the electrostatic latent image. Adhere to the electrostatic latent image. On the other hand, the toner that reaches the vicinity of the background portion (uniformly charged portion) of the photoreceptor 1 near the apex of the parabolic hopping locus descends without departing from the hopping locus and lands on the surface of the flare roller 61. To do.

  In such a configuration, by using toner in a state where the adsorptive power to the flare roller 61 is released by hopping, low potential development that could not be realized by the conventional one-component development method or two-component development method. Can be realized.

The structure of the flare roller 61 will be described with reference to FIG.
Examples of the support substrate 69 include a base material made of an insulating material such as a glass base material, a resin base material, and a ceramic base material. Further, a substrate made of a conductive material such as stainless steel and an insulating film such as SiO ₂ may be formed, or a base material made of a material that can be deformed flexibly such as a polyimide film may be used.

  The electrodes 66 (A-phase electrode 66a and B-phase electrode 66b) are formed on a support substrate 69 with a conductive material such as Al or Ni—Cr in a thickness of 0.1 to 10 μm, preferably 0.5 to 2.0 μm. A film is formed and patterned into a required electrode shape by a photolithographic technique or the like.

As the surface protective layer 68, for example, a film formed of a material such as SiO ₂ , BaTiO ₂ , TiO ₂ , TiO ₄ , SiON, BN, TiN, Ta ₂ O ₅ can be exemplified. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin. The surface protective layer 68 is appropriately selected from the relationship between the insulating property, durability, the manufacturing method of the flare roller itself, and the charge train with the toner to be used.

  Next, the electrode width L and electrode interval R of the electrode 66 of the flare roller 61 and the thickness of the surface protective layer 68 will be described. The electrode width L and the electrode interval R in the flare roller 61 greatly influence the toner hopping efficiency. The electrode pitch P is represented by P = R + L.

  The toner between the electrodes moves on the substrate to an adjacent electrode position by an electric field in a substantially horizontal direction. On the other hand, since the toner on the electrode is given an initial velocity having at least a component in the vertical direction, most of the toner flies away from the substrate. In particular, since the toner near the electrode end surface moves over the adjacent electrode, when the electrode width L is wide, the number of toners on the electrode increases, and the toner having a large moving distance increases. However, if the electrode width L is too wide, the electric field strength in the vicinity of the center of the electrode is lowered, so that the toner adheres to the electrode and the hopping efficiency is lowered. Therefore, as a result of intensive studies, the present inventors have found that there is an appropriate electrode width for efficiently hopping toner at a low voltage.

  The electrode interval R determines the electric field strength between the electrodes from the relationship between the distance and the applied voltage. The smaller the interval R, the stronger the electric field strength, and the easier the initial hopping speed is obtained. However, toner that moves from electrode to electrode has a short moving distance, and unless the drive frequency is increased, the hopping time is shortened and the landing time is lengthened. As a result of intensive studies, the present inventors have found that there is an appropriate electrode interval for efficiently transporting and hopping toner at a low voltage.

  Further, it has also been found that the thickness of the surface protective layer 68 covering the electrode surface also affects the electric field strength on the electrode surface, and in particular, the influence of the vertical component on the electric field lines is large, which determines the hopping efficiency.

  That is, by appropriately setting the relationship among the electrode width L, the electrode interval R, and the thickness of the surface protective layer 68 of the flare roller 61, efficient hopping can be performed at a low voltage. Therefore, in this embodiment, the electrode width L is 1 to 20 times the average toner particle diameter, and the electrode interval R is also 1 to 20 times the toner average particle diameter. The thickness of the surface protective layer 68 is 0.5 to 10 [μm], preferably 0.5 to 3 [μm].

  Further, when the flare roller 61 is used in the image forming apparatus according to the present embodiment, it is necessary to use a fine pattern in which the electrode 66 is formed in a large area with a length of at least A4 vertical width of 21 cm or a horizontal width of 30 cm or more. It becomes. Therefore, some examples of the manufacturing method of the flare roller 61 will be described.

  First, a case where a flare roller 61 is formed by forming a flexible electrode pattern and winding it around a support drum will be described. As an example of a substrate having a flexible fine pitch thin layer electrode, a polyimide base film (thickness 20 to 100 μm) is used as a base material (supporting substrate 69), and 0.1 to 0.3 μm is deposited thereon by vapor deposition. Cu, Al, Ni—Cr or the like is deposited. If it is 30-60 cm in width, it can be manufactured by a roll-to-roll apparatus, and mass productivity is greatly increased. The common bus line simultaneously forms electrodes having a width of about 1 to 5 mm.

  As specific means of the vapor deposition method, a sputtering method, an ion plating method, a CVD method, an ion beam method, or the like can be used. For example, when an electrode is formed by sputtering, a Cr film may be interposed in order to improve adhesion with polyimide, and adhesion can also be improved by plasma treatment or primer treatment.

  Further, as a method other than the vapor deposition method, a thin layer electrode can be formed also by an electrodeposition method. In this case, an electrode is first formed on the polyimide substrate by electroless plating. A base electrode can be formed by sequentially immersing in Sn chloride, Pd chloride, and Ni chloride, and then electroplating can be performed in a Ni electrolyte solution to produce a Ni film of 1 to 3 μm in a roll-to-roll manner.

  Then, an electrode 66 is formed on these thin film electrodes by resist coating, patterning, and etching. In this case, if the electrode is a thin layer electrode having a thickness of 0.1 to 3 μm, a fine pattern electrode having a width of 5 μm to several tens of μm or an interval can be accurately formed by photolithography and etching.

Next, SiO ₂ , BaTiO ₂ , TiO ₂ or the like is formed as the surface protective layer 68 by sputtering or the like with a thickness of 0.5 to ₂ μm. Alternatively, PI (polyimide) is applied as a surface protective layer 68 to a thickness of 2 to 5 μm using a roll coater or other coating apparatus, and baked to finish. When troubles occur with PI, it is sufficient to form SiO2 on the outermost surface and other inorganic films to a thickness of 0.1 to 0.5 [mu] m by sputtering or the like. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin.

  By configuring such a flexible substrate, it can be easily attached to a cylindrical drum, or partially curved.

  As another example, a polyimide base film (thickness 20 to 100 μm) is used as a base material (supporting substrate 69), and an electrode material thereon is used such as Cu or SUS having a thickness 10 to 20 μm. Is also possible. In this case, conversely, polyimide is applied on a metal material with a roll coater by 20 to 100 μm and baked. After that, when the metal material is patterned into the shape of the electrode 66 by photolithography and etching, polyimide is coated on the surface of the electrode 66 as the surface protective layer 68, and there are irregularities according to the thickness of the metal material electrode of 10 to 20 μm. Flatten to complete.

  For example, when a polyimide material or a polyurethane material having a viscosity of 50 to 10,000 cps, more preferably 100 to 300 cps is spin-coated and left standing, the unevenness of the substrate is smoothed by the surface tension of the material, and the outermost surface of the conveying member is Flattened.

  Furthermore, as still another example of increasing the strength of the flexible substrate, SUS, Al material, etc. having a thickness of 20 to 30 μm is used as a base material (support substrate 69), and an insulating layer (electrode and base material) is formed on the surface thereof. As an insulation between the two, a diluted polyimide material of about 5 μm is coated with a roll coater. The polyimide is then pre-baked at 150 ° C. for 30 minutes and post-baked at 350 ° C. for 60 minutes to form a thin-layer polyimide film, which is used as the support substrate 69.

Then, after performing plasma treatment and primer treatment for improving adhesion, Ni—Cr is deposited as a thin electrode layer to a thickness of 0.1 to 0.2 μm, and the fine pattern electrode of several tens of μm is formed by photolithography and etching. 66 is formed. Furthermore, a flexible transport member can be obtained by forming the surface protective layer 68 such as SiO ₂ , BaTiO ₂ , TiO ₂ or the like on the surface by sputtering to a thickness of about 0.5 to 1 μm. Further, an organic material such as polycarbonate may be coated on SiO ₂ or the like. It is also possible to select zirconia or a material generally used as a coating material for a carrier of a two-component developer, for example, a silicone resin.

As another manufacturing method of the flare roller 61, there is also a method of patterning an electrode and forming a surface protective layer 68 on a cylindrical drum from the beginning. As an example, there is a construction method as shown in FIG. In this embodiment, pattern electrodes are formed by steps a to e in FIG. FIG. 7 is a view when the surface of the flare roller is viewed in the direction along the rotation axis. In step a, the surface of the roller is finished smoothly by peripheral turning. In step b, groove cutting is performed so that the groove pitch is 100 μm and the groove width is 60 μm. In step c, electroless nickel plating is performed, and in step d, the outer periphery is turned to remove unnecessary conductor films. At this point, an electrode is formed in the groove portion. In step e, the roller surface was smoothed by coating with a silicone resin, and at the same time, the surface protective layer 68 was formed. At this time, the thickness of the surface protective layer 68 was about 5 μm and the volume resistivity was about 10 ¹⁰ Ω · cm.

  Further, as another manufacturing method of the flare roller 61, a screen printing using a conductive ink, an ink jet printing, and a method of removing a non-electrode portion of a plated electrode by laser processing may be used. The method of creating the electrode pattern of the flare roller 61 and the surface protective layer 68 is not limited to the above-described method, and silver, copper, or the like may be used as the electrode material.

  In the color superposition system using such a flare development type developing device, the flare roller 61 and the photosensitive member 1 are not in contact with each other and no alternating electric field is applied at the development position. The toner image once formed on the photoconductor 1 is not affected mechanically or in electric field, so there is no problem of scavenging or color mixing, and it is stable over a long period of high-quality image forming process. Can be done.

  In the flare developing type developing device 4 having such a configuration, electric charges gradually accumulate in the insulating surface protective layer 68 of the flare roller 61 over time, and the surface potential largely fluctuates, resulting in the flare roller. The potential difference between the surface 61 and the photosensitive member 1 fluctuates, resulting in density unevenness, background contamination, and the like. As a result of intensive studies on this mechanism, the present inventors have found that the following are the factors that cause fluctuations in the surface potential of the flare roller 61.

1. Charge accumulation by capacitor model (see Fig. 11 and Fig. 12)
In order to eliminate the toner and extract only the influence of the supply roller 62 and the flare roller 61, only the supply roller 62 and the flare roller 61 were idly rotated, and the time transition of the surface potential of the flare roller 61 was measured. In order to improve the supply efficiency of the toner to the flare roller 61, a supply voltage is applied to the supply roller 62 so as to provide a potential difference Vp between the flare roller 61 and the supply roller 62. In FIG. 11, the measurement result of the time transition of the flare roller 61 surface potential is shown. As shown in FIG. 11, charges are accumulated in the surface protective layer 68 of the flare roller 61 until the potential difference Vp between the surface potentials of the supply roller 62 and the flare roller 61 disappears, and the potential is saturated. This behavior is nothing but the surface potential of the capacitor generated by the charge accumulated in the capacitor of the RC series circuit shown in FIG. If the power supply of the supply voltage applied to the supply roller 62 and the voltage applied to the flare roller 61 are turned off and left to stand, charges are gradually lost, but the surface protective layer 68 has a high resistance to provide insulation between the electrodes. For this reason, the stored charge does not readily leak naturally. Therefore, it is considered difficult to establish a system without providing a static elimination function.

2. Frictional charging of flare roller and supply roller (see Fig. 13)
Among the influences of the surface potential of the supply roller 62 and the flare roller 61, the above 1. Further, the influence of the supply voltage applied to the supply roller 62 and the voltage applied to the flare roller 61 is removed, and only the frictional charging characteristics of both are examined. That is, the supply voltage and the two-phase voltage applied to the flare roller 61 were all connected to the ground, and the time transition of the flare roller surface potential was measured in the same manner. FIG. 13 shows the measurement results of the time transition of the flare roller 61 surface potential. As shown in FIG. 13, it was found that the flare roller was charged by about −40 V only by frictional charging of the flare roller 61 and the supply roller 62. The value of −40V and the convergence speed are affected by the relationship between the charging series of the surface protection layer 68 material of the supply roller 62 and the flare roller 61, the amount of biting of the supply roller 62, and the like.

3. Induction of charge to cancel negative charge of toner (see FIG. 14)
When the negatively charged toner supplied from the supply roller 62 is hopping on the flare roller 61, a positive charge of reverse charge is induced in the surface protective layer 68 of the flare roller 61, and the surface of the flare roller 61 after the toner is removed. When the potential is measured, it has a positive surface potential. This value becomes more remarkable as the charge amount of the toner is higher.

  Here, the above 1. If only the accumulation of electric charges by the capacitor model is performed, the supply and recovery of the toner may be relied only on mechanical scraping, and the surface potential may vary unless the potential difference Vp is provided between the flare roller 61 and the supply roller 62. Can be avoided. However, 2. 2. friction charging between the flare roller and the supply roller; The surface protective layer 68 is charged by the induction of charge that cancels the negative charge of the toner. Further, the surface protective layer 68 is charged by frictional charging between the regulating member 63 in contact with the flare roller 61 and the surface protective layer 68. As the surface protective layer 68 is gradually charged in this manner, the surface potential of the flare roller largely fluctuates.

  In the developing device 4 of this embodiment, in order to suppress the fluctuation of the surface potential of the flare roller 61, the conductive contact member 71 is provided downstream from the developing position and upstream from the regulating member 63. The conductive contact member 71 is a foamed member formed in a thin plate shape, and elastically contacts the flare roller 61. Then, the A-phase flare roller power supply 24a and the B-phase flare roller power supply 24b that are the flare roller power supply 24 are applied to the A-phase electrode group 66A and the B-phase electrode group 66B that are the electrodes 66 of the flare roller 61, respectively. A voltage having an average value equal to the average value of the voltage is applied to the conductive contact member 71 from a contact member power supply (not shown) as the contact member voltage application means. Hereinafter, it demonstrates concretely based on an Example and a comparative example.

<Example 1>
In the developing device 4 of FIG. 2, in order to hop toner, voltages applied to the A-phase electrode group 66A and the B-phase electrode group 66B from the A-phase flare roller power source 24a and the B-phase flare roller power source 24b are as follows. A rectangular wave voltage having an opposite phase as shown in FIG. 6B was used. Specifically, both the A-phase electrode group 66A and the B-phase electrode group 66B are rectangular wave voltages having an average value Vo of −200 V, a frequency f of 1 kHz, a peak-to-peak voltage Vpp of 300 V, and a duty of 50%. A supply voltage is applied to the supply roller 62 so as to provide a potential difference Vp + 250 between the flare roller 61 and the supply roller 62 in order to improve the efficiency of supplying toner to the flare roller 61. Vo-200V was applied as a DC voltage to the conductive contact member 71 from a power supply for contact member (not shown). The average value Vave of the voltages applied to the A-phase electrode group 66A and the B-phase electrode group 66B of the flare roller 61 matches the offset voltage Vo of the rectangular wave voltage when the duty is 50% in this way. Therefore, the average value Vave of the voltage applied to the A-phase electrode group 66A and the B-phase electrode group 66B of the flare roller 61 is −200V, and the DC voltage −200V applied to the conductive contact member 71 has the same average value. Have. On the other hand, when the average value Vave of the voltage applied to the flare roller 61 does not coincide with the offset voltage Vo, such as when the duty of the rectangular wave voltage is not 50%, the average of the voltage applied to the flare roller 61 according to the Duty etc. A DC voltage having a value Vave is applied to the conductive contact member 71.

  As described above, even if the flare roller 61 is continuously rotated by setting the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 to the same potential, the flare roller surface potential Can always be kept constant. Further, even when the flare roller 61 is continuously rotated, the toner adhesion amount and the charge amount after the layer thickness regulation by the regulation member 63 are constant. Furthermore, what measured the time change of the cloud electric potential of the flare roller 61 is shown in FIG. The cloud potential refers to the surface including the toner in a state where the toner is attached on the flare roller 61 and the toner is formed in a cloud shape by applying a voltage to the flare roller 61 and hopping. The potential is measured, and it can be said that the potential represents actual development characteristics. As shown in FIG. 8, by applying a voltage to the conductive contact member 71 under the conditions of the first embodiment, the cloud potential of the flare roller 61 becomes constant. If the cloud potential is constant, the potential difference from the latent image potential on the photosensitive member 1 is kept constant, so that the image density is stable, no background smearing occurs, and good image formation can be performed. It was. In FIG. 8, the very initial change in cloud potential until about 2 seconds from the start of flare roller rotation is until the toner is carried on the flare roller 61 in the experiment, and does not cause a problem during actual image formation.

<Comparative example>
In the developing device 4 of FIG. 2, the voltage applied to the flare roller 61 for hopping the toner is the same as that in the first embodiment. Vo-400V was applied to the conductive contact member 71 as a DC voltage. Thus, if the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 are different, it is difficult to maintain the flare roller surface potential constant. Further, FIG. 9 shows the time variation of the cloud potential of the flare roller 61 measured. As shown in FIG. 9, the cloud potential continued to decrease until about 20 seconds after the flare roller rotation started. At this time, the potential difference from the latent image potential on the photosensitive member 1 was increased, resulting in a problem that the image density was increased and scumming was generated. Further, since the potential difference between the flare roller 61 and the supply roller 62 is substantially smaller than the initial value, a problem that a sufficient amount of toner is not supplied to the flare roller 61 also occurs. From these results, even when a voltage is applied to the conductive contact member 71 under the conditions of the comparative example, the fluctuation of the surface potential of the flare roller 61 cannot be suppressed, the image density is increased, and background staining is also generated. The problem that occurred.

<Example 2>
A voltage as shown in FIG. 6A is used as the voltage applied to the flare roller 61 for hopping the toner in the developing device 4 of FIG. Specifically, the A-phase electrode group 66A is a rectangular wave voltage having an average value Vo of −300 V, a frequency f of 1 kHz, a peak-to-peak voltage Vpp of 600 V, and a duty of 50%. A DC voltage of −300 V was applied to the B-phase electrode group 66B. Thus, even if a rectangular wave voltage is applied to one of the two-phase electrode groups and a constant DC voltage is applied to the other electrode group, the toner can be similarly hopped. It is. By making one voltage applied to the flare roller 61 a DC voltage, the number of power supply systems that generate pulses can be reduced by one, and the cost of the power supply can be reduced. A DC voltage of −300 V was applied to the conductive contact member 71.
Even if the flare roller 61 is continuously rotated by setting the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 to the same potential as in the above condition, the flare roller surface potential Can always be kept constant. In addition, the cloud potential was also constant, and the image density was stable and good image formation with no background stain could be performed.

<Example 3>
The voltage applied to the flare roller 61 for hopping the toner in the developing device 4 of FIG. 2 is a rectangular wave voltage having an opposite phase as shown in FIG. Specifically, both the A-phase electrode group 66A and the B-phase electrode group 66B are rectangular wave voltages having an average value Vo of −300V, a frequency f of 1 kHz, a peak-to-peak voltage Vpp of 300V, and a duty of 50%. Further, a rectangular wave voltage having an average value Vo of −300 V, a frequency f of 500 Hz, and a peak-to-peak voltage Vpp of 200 V was applied to the conductive contact member 71. Even if the flare roller 61 is continuously rotated by setting the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 to the same potential as in the above condition, the flare roller surface potential Can always be kept constant. In addition, the cloud potential was also constant, and the image density was stable and good image formation with no background stain could be performed.

<Example 4>
In the developing device 4 of FIG. 2, the voltage applied to the flare roller 61 for hopping the toner is the same as that in the third embodiment. Further, the conductive contact member 17 has the same rectangular wave voltage as one of the rectangular wave voltages of the antiphase rectangular wave voltages applied to the A phase electrode group 66A and the B phase electrode group 66B of the flare roller 61. Was applied. Even if the flare roller 61 is continuously rotated by setting the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 to the same potential as in the above condition, the flare roller surface potential Can always be kept constant. In addition, the cloud potential was also constant, and the image density was stable and good image formation with no background stain could be performed.

<Example 5>
The voltage applied to the flare roller 61 for hopping the toner in the developing device 4 in FIG. 2 is a voltage as shown in FIG. Specifically, the A-phase electrode group 66A is a rectangular wave voltage having an average value Vo of −300 V, a frequency f of 1 kHz, a peak-to-peak voltage Vpp of 600 V, and a duty of 50%. A DC voltage of −300 V was applied to the B-phase electrode group 66B. The voltage applied to the conductive contact member 71 is the same rectangular wave voltage as that applied to the A-phase electrode group 66 </ b> A of the flare roller 61. Even if the flare roller 61 is continuously rotated by setting the average value of the voltage applied to the flare roller 61 and the voltage applied to the conductive contact member 71 to the same potential as in the above condition, the flare roller surface potential Can always be kept constant. In addition, the cloud potential was also constant, and the image density was stable and good image formation with no background stain could be performed.

  In Examples 1 to 5, a foamed member is used as the conductive contact member 71. However, felt, a nonwoven fabric, a fur brush, a rubber member, or the like can be used as the conductive contact member. Further, the shape of the conductive contact member is not limited to a plate shape, and may be a roller-shaped conductive contact roller 72 as shown in FIG.

  Further, the rotation direction of the flare roller 61 is not limited to the counterclockwise direction shown in FIG. 2 and may be the opposite direction. FIG. 16 is a schematic configuration diagram of the flare roller 61 reversed using a plate-like conductive contact member 71, and FIG. 17 is a schematic diagram of the flare roller 61 reversed using a conductive contact roller 72. It is a block diagram.

  Further, as shown in FIG. 16, the conductive contact roller 72 may be provided downstream of the supply roller 62, and the restriction member 63 may be disposed downstream of the conductive contact roller 72. As described above, if the positions of the conductive contact member 71 and the conductive contact roller 72 are downstream from the development position and upstream from the regulating member 63, the positional relationship with the supply roller 62 and the collection roller is limited. It is not something.

  10 and 17 collectively show the toner supply function, the recovery function, and the flare roller surface potential stabilization function as one conductive supply roller 73. Even with such a configuration, by applying the voltage to the conductive supply roller 73, the flare roller surface potential can be maintained constant, and a good image free from unevenness in image density and free from background contamination can be obtained. .

As described above, according to the present embodiment, the conductive contact member 71 that contacts the flare roller 61 is provided downstream of the development position and upstream of the regulating member 63. Then, the A-phase flare roller power supply 24a and the B-phase flare roller power supply 24b that are the flare roller power supply 24 are applied to the A-phase electrode group 66A and the B-phase electrode group 66B that are the electrodes 66 of the flare roller 61, respectively. A voltage having an average value equal to the average value of the voltage is applied to the conductive contact member 71. Thereby, the surface potential of the flare roller 61 can be kept constant.
Further, as the voltages applied to the A-phase electrode group 66A and the B-phase electrode group 66B of the flare roller 61, rectangular wave voltages having opposite phases as shown in FIG. 6B were used. Further, the same DC voltage as the average value Vave of the voltage applied to the flare roller 61 is applied to the conductive contact member 71. Thereby, the surface potential of the flare roller 61 can be kept constant.
Further, as the voltage applied to the flare roller 61, as shown in FIG. 6A, a rectangular wave voltage was used for the A-phase electrode group 66A, and a DC voltage was used for the B-phase electrode group 66B. Thus, even if a rectangular wave voltage is applied to one of the two-phase electrode groups and a constant DC voltage is applied to the other electrode group, the toner can be similarly hopped. By making one voltage a DC voltage, the number of power supply systems that generate pulses can be reduced by one, and the cost of the power supply can be reduced. Further, the same DC voltage as the average value Vave of the voltage applied to the flare roller 61 is applied to the conductive contact member 71. Thereby, the surface potential of the flare roller 61 can be kept constant.
Further, as the voltages applied to the A-phase electrode group 66A and the B-phase electrode group 66B of the flare roller 61, rectangular wave voltages having opposite phases as shown in FIG. 6B were used. Further, a rectangular wave voltage having the same average value as the average value Vave of the voltage applied to the flare roller 61 is applied to the conductive contact member 71. Thereby, the surface potential of the flare roller 61 can be kept constant. Furthermore, a flare roller power source is applied to the conductive contact member 71 by applying a rectangular wave voltage identical to the rectangular wave voltage applied to either the A-phase electrode group 66A or the B-phase electrode group 66B. 24 can be used to supply voltage to the conductive contact member 71. Therefore, only two systems of the flare roller power source 24 are required without newly providing the contact member application power source, and the cost of the power source can be reduced.
Further, as the voltage applied to the flare roller 61, as shown in FIG. 6A, a rectangular wave voltage was used for the A-phase electrode group 66A, and a DC voltage was used for the B-phase electrode group 66B. Further, a rectangular wave voltage having the same average value as the average value Vave of the voltage applied to the flare roller 61 is applied to the conductive contact member 71. Thereby, the surface potential of the flare roller 61 can be kept constant. As a result, only one system of rectangular wave voltage output is required, and the cost of the power supply can be reduced.
In addition, by using a non-woven fabric as the conductive contact member 71, the stress on the flare roller 61 can be reduced with a simple configuration.
Further, by using an elastic member such as an elastic blade as the conductive contact member 71, a simple configuration can be achieved.
Further, by using a foam member as the conductive contact member 71, a simple configuration can be achieved.
Further, by using a fur brush as the conductive contact member 71, a simple configuration can be achieved.
Further, by using a roller-shaped member as the conductive contact member 72, a stable effect can be obtained over a long period of time.
Further, by using a roller-like member as the conductive supply roller 73 and also having a function as a supply roller, the developing device can be reduced in size and cost.
In addition, in the image forming apparatus using the developing device 4, it is possible to obtain a good image free from image density unevenness and background stains.
Further, the developing device 4 can perform development without contact with the photosensitive member 1, and can perform color superimposition a plurality of times on the photosensitive member 1 to obtain a high-quality color image without color misregistration. it can. Further, the photoreceptor 1 is less deteriorated and can be highly durable.
Further, maintenance performance can be improved by integrally holding the developing device 4 and the charging device 2 and making the process cartridge detachable from the main body.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram of a developing device. The perspective view which shows schematic structure of a flare roller. The plane expanded view of the electrode part of a flare roller. The circumferential direction cross-sectional enlarged view of the electrode part of a flare roller. It is a wave form diagram of the voltage applied to the two-phase electrode group of a flare roller, (a) is a rectangular wave voltage, the other one phase is a direct current voltage, and (b) is a rectangular wave voltage of an antiphase. Explanatory drawing of the process of a flare roller manufacturing method. 3 is a graph showing changes in cloud potential of a flare roller under the conditions of Example 1. FIG. The graph which shows the cloud electric potential change of the flare roller by the conditions of a comparative example. FIG. 3 is a schematic configuration diagram of an example of a developing device using a conductive supply roller. The graph which shows the flare roller surface potential change by a capacitor | condenser model. Explanatory drawing of a capacitor model. The graph which shows the flare roller surface potential change by the frictional charging of a supply roller and a flare roller. The graph which shows the flare roller surface potential change by the charge induction to the flare roller surface by a charging toner. FIG. 3 is a schematic configuration diagram of a developing device using a conductive contact roller. The schematic block diagram of the image development apparatus which made the flare roller into the reverse direction using the plate-shaped electroconductive contact member. The schematic block diagram of the other example of the image development apparatus using an electroconductive supply roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure part 4 Developing device 6 Process unit 61 Flare roller 62 Supply roller 63 Control member 64 Paddle 65 Toner leakage prevention member 66 Electrode 66a A phase electrode 66b B phase electrode 67a A phase common electrode 67b B phase Common electrode 68 Surface protective layer 69 Support base 70 Casing 71 Conductive contact member (plate-shaped)
72 conductive contact roller 73 conductive supply roller

Claims (16)

A plurality of electrodes arranged in a predetermined direction; and a toner carrier including an insulating surface protective layer that protects the electrodes;
Toner supply means for supplying toner to the surface of the toner carrier;
A voltage that changes with time at a predetermined cycle in at least some of the electrodes so as to form an oscillating electric field in which the toner repeatedly moves back and forth by hopping between adjacent electrodes among the plurality of electrodes of the toner carrier. Electrode voltage applying means for applying
While hopping the toner on the surface of the toner carrier, after passing through the toner thickness regulating position by the regulating member as the surface of the toner carrier moves, to the developing position that is the position facing the latent image carrier In the developing device for transporting and attaching to the latent image on the latent image carrier,
A conductive contact member disposed to contact the surface of the toner carrier downstream of the development position and upstream of the regulating member with respect to the surface movement direction of the toner carrier, and a voltage applied to the contact member A contact member voltage applying means for applying a voltage, an average value of voltages applied to the contact member by the contact member voltage applying means, and a voltage applied to the electrode of the toner carrier by the electrode voltage applying means. A developing device characterized in that the average value is the same.   2. The developing device according to claim 1, wherein the voltage applied to one of the adjacent electrodes of the toner carrier by the electrode voltage applying means and the voltage applied to the other electrode are temporally opposite in phase. And a voltage applied to the contact member by the contact member voltage application means is a DC voltage.   2. The developing device according to claim 1, wherein the voltage applied to one electrode group among the adjacent electrodes of the toner carrier by the electrode voltage applying means is a voltage having a waveform that changes with time, and is applied to the other electrode group. The developing device is characterized in that the voltage to be applied is a DC voltage, and the voltage applied to the contact member by the contact member voltage applying means is a DC voltage.   2. The developing device according to claim 1, wherein the voltage applied to one of the adjacent electrodes of the toner carrier by the electrode voltage applying means and the voltage applied to the other electrode are temporally opposite in phase. And a voltage applied to the contact member by the contact member voltage applying means is a voltage having a waveform that changes with time.   5. The developing device according to claim 4, wherein a voltage applied to the contact member by the contact member voltage application unit is applied to either the one electrode group or the other electrode group by the electrode voltage application unit. A developing device having the same voltage.   2. The developing device according to claim 1, wherein the voltage applied to one electrode group among the adjacent electrodes of the toner carrier by the electrode voltage applying means is a voltage having a waveform that changes with time, and is applied to the other electrode group. The voltage to be applied is a DC voltage, and the voltage applied to the abutting member by the abutting member voltage applying means is the same as the time-varying voltage applied to the one electrode group. A developing device.   7. The developing apparatus according to claim 1, wherein the contact member is a non-woven fabric.   7. The developing device according to claim 1, wherein the contact member is an elastic body.   7. The developing device according to claim 1, wherein the contact member is a foam.   7. The developing device according to claim 1, wherein the contact member is a fur brush.   7. The developing device according to claim 1, wherein the contact member is a cylindrical roller.   12. The developing device according to claim 11, wherein the cylindrical roller also has a function as toner supply means for supplying toner to the toner carrier. An image comprising: a latent image carrier; a latent image forming unit that forms an electrostatic latent image on the latent image carrier; and a developing unit that develops the electrostatic latent image formed on the latent image carrier. In the forming device,
An image forming apparatus using the developing device according to claim 1 as the developing means.   14. The image forming apparatus according to claim 13, wherein a plurality of the developing devices are provided, development is performed by the plurality of developing devices, and images are superimposed on the latent image carrier to form a multicolor image. apparatus.   15. The image forming apparatus according to claim 13, further comprising: a process cartridge that integrally holds at least one of the latent image carrier, the charging unit, and the cleaning unit and the developing unit, and is detachable from the main body. An image forming apparatus.   13. The process cartridge according to claim 1, wherein at least one of a latent image carrier, a charging unit, and a cleaning unit and a developing unit are integrally held and detachable from the main body of the image forming apparatus. A process cartridge characterized by employing a developing device.

Images