JP4138263B2 - Electrostatic transfer device, developing device, and image forming apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electrostatic conveyance device, a developing device, and an image forming apparatus, and more particularly to an electrostatic conveyance device that conveys powder by electrostatic force, a developing device that attaches toner to a latent image carrier, and a latent image on a latent image carrier. The present invention relates to an image forming apparatus that develops and forms an image.
[0002]
[Prior art]
As an image forming apparatus such as a copying apparatus, a printer, or a facsimile, an electrophotographic process is used to form a latent image on a latent image carrier, and a developer (hereinafter referred to as “toner”) is attached to the latent image for development. In some cases, a visible image is formed and the toner image is transferred to a recording medium (transfer paper) to form an image.
[0003]
In such an image forming apparatus, as a developing device for developing a latent image, conventionally, the toner stirred in the developing device is carried on the surface of the developing roller as a developer carrying member, and the developing roller is rotated. The latent image carrier is transported to a position facing the surface of the latent image carrier, and the latent image on the latent image carrier is developed. After the development, the toner that has not adhered to the latent image carrier is collected in the developing device by the rotation of the developing roller. In addition, there is a known toner that is newly stirred and charged and then carried again on the developing roller and conveyed.
[0004]
As a developing device, as described in Japanese Patent Laid-Open No. 5-19615, toner is transported using electrostatic force on the surface of the developing roller and developed with suction force generated between the latent image carrier and the developing device. An electrostatic transport substrate that separates toner from the roller surface and adheres to the surface of the latent image carrier, or an electrostatic transport substrate that transports toner with electrostatic force as described in JP-A-59-181375 The toner is transported to a position facing the latent image carrier, and the toner is separated from the electrostatic transport substrate by the suction force generated between the latent image carrier and adhered to the surface of the latent image carrier. As described in Japanese Patent Application Laid-Open No. 7-227995, as described in Japanese Patent Application Laid-Open No. 4-204570, charging is performed by exciting vibrations on a conveyance substrate that conveys toner. particle Such as those of the transport substrate and excited by vibration conveys the charged particle performs with electrostatic conveyance is known.
The
[0005]
Further, as another image forming apparatus, a developing roller for carrying toner and an electrode substrate on which stripe-shaped electrodes described in JP-A-9-141912 are used to carry and carry toner to the aperture portion. The control electrode is disposed between the recording medium and the back electrode is disposed on the back surface of the recording medium, and an electric field is generated between the back electrode and the developing roller, so that the toner can fly in the direction of the recording medium, A so-called flying type (toner jet type) image forming apparatus that forms an image on a recording medium by selectively controlling the flying of the toner with a control electrode is also known.
[0006]
Further, as a powder conveying apparatus for conveying powder such as toner, there is an apparatus that conveys a space traveling wave electric field as described in JP-A-7-267363. This is because when a driving voltage is applied to the electrode, a spatial traveling wave electric field is formed around the electrode, and a repulsive force and a driving force act on the powder charged by the traveling wave electric field, so that the powder travels in the electric field. It is conveyed in the direction. As a classifying device for classifying powders such as toner using this space traveling wave electric field, for example, as described in JP-A-8-149859, classification is performed by applying electrostatic force, gravity, centrifugal force, etc. (Sorting) has been proposed.
[0007]
[Problems to be solved by the invention]
However, the image forming apparatus provided with a developing device that applies toner to the latent image carrier using the developing roller described above, or the toner is carried on the developing roller, and the toner is ejected from the developing roller to the recording medium by electric field control. In the flying type image forming apparatus, since the developing roller is used, the developing apparatus becomes large, and the entire image forming apparatus cannot be reduced in size and cost.
[0008]
Further, in a developing device that conveys toner by electrostatic conveyance, the toner cannot be reliably conveyed. That is, in order to perform electrostatic conveyance, charged particles need to be charged to a predetermined charge in advance. However, in toners used for electrophotography and the like, variations in the amount of charged charges have been confirmed. When the charged charges of the particles are different, the same conveying force is not applied to the particles even if the same conveying electric field is used, and thus there is a problem that the accuracy of the conveying amount and the conveying speed cannot be controlled.
[0009]
On the other hand, those that vibrate the transport substrate and transport the particles by the energy of vibration have the advantage that they can be transported without having to charge the particles, but the transport speed can be controlled only by vibration conditions, Since the conveying force applied to the body is due to the frictional force of contact between the particles and the transfer substrate, it is difficult to apply a friction force between the particles and the transfer substrate, for example, the particle diameter is too small and transferred. In the case where sufficient energy from the substrate cannot be obtained, there is a problem that the particles float and slip from the transfer substrate and the transfer force is reduced.
[0010]
Further, in the case where the charged particles are transported by electrostatic force and the vibration of the transport substrate, the charged particles floating from the transport substrate are sent back by wind pressure such as vortex generated by the rotation of the latent image carrier, etc. There exists a subject that it cannot convey reliably in a conveyance direction.
[0011]
The present invention has been made in view of the above points. An electrostatic transport apparatus that can reliably transport powder in a required direction and has improved transport efficiency, and development with high image quality using the electrostatic transport apparatus. An object of the present invention is to provide a developing device capable of performing the above and an image forming apparatus capable of forming a high-quality image using the developing device.
[0012]
[Means for Solving the Problems]
  In order to solve the above problems, an electrostatic transfer device according to the present invention is:
  In an electrostatic transport device that transports powder with electrostatic force,
  A first substrate having a plurality of electrodes for generating an electric field for moving the powder with electrostatic force along the conveying surface;
  A second substrate that is disposed to face the first substrate with a gap, and has a sloped surface and a steep surface with a steeper angle than the sloped surface.
  The second substrate includes a divided vibration generating substrate formed by dividing a vibration generating substrate having a piezoelectric material layer and an electrode sandwiching the piezoelectric material layer by dividing grooves as means for vibrating the second substrate,
  The electrode pitch of the divided vibration generating substrate is substantially the same as the electrode pitch of the first substrate, and the electrode of the divided vibration generating substrate and the electrode of the first substrate are arranged to face each other,
  The divided vibration generating substrate is vibrated by applying an AC or DC pulse to the electrode of the divided vibration generating substrate in synchronization with the drive waveform for the electrode of the first substrate.
The configuration.
  In this specification, “powder” includes “fine particles”, “fine powder”, “particles”, “powder”, “particles”, “fine powder”, and the like.
[0013]
  here,A conveying surface forming member that is a vibration propagation member that forms a conveying surface on the divided vibration generating substrate is provided, and an electrode is provided in the vicinity of the top of the inclined surface of the conveying surface forming member. A driving waveform can be applied to the electrodes on the inclined surface. Also,The inclined surface of the second substrate and the bottom side continuous portion of the steep surface form a curved surface shape.Can be configured.
[0022]
A developing device according to the present invention is a developing device that develops a latent image on a latent image carrier by depositing toner on the latent image carrier, and includes the electrostatic transport device according to the present invention. The tip of the electrostatic transfer substrate of the transfer device is configured to face the vicinity of the latent image carrier.
[0023]
A developing device according to the present invention is a developing device that develops a latent image on a latent image carrier by depositing toner on the latent image carrier, and includes the electrostatic conveyance device according to the present invention. In this configuration, toner is sent to the developing means attached to the image carrier by an electrostatic conveyance device.
[0024]
An image forming apparatus according to the present invention is an image forming apparatus including a developing device that develops a latent image on a latent image carrier by attaching toner on the latent image carrier, and the developing device according to the present invention is provided. It is provided.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 2 is an overall schematic configuration diagram of the image forming apparatus.
The overall outline and operation of the image forming apparatus will be described. A photosensitive drum 1 (for example, an organic photosensitive member: OPC), which is a latent image carrier, is rotationally driven clockwise in FIG. When a document is placed on the contact glass 2 and a print start switch (not shown) is pressed, the scanning optical system 5 including the document illumination light source 3 and the mirror 4 and the scanning optical system 8 including the mirrors 6 and 7 are moved. The original image is read.
[0026]
Here, the scanned document image is read as an image signal by the image reading element 10 disposed behind the lens 9, and the read image signal is digitized and subjected to image processing. Then, a laser diode (LD) is driven by the signal subjected to the image processing, and laser light from the laser diode is reflected by the polygon mirror 13 and then irradiated onto the photosensitive drum 1 through the mirror 14. The photosensitive drum 1 is uniformly charged by a charging device 15, and an electrostatic latent image is formed on the surface of the photosensitive drum 1 by writing with a laser beam.
[0027]
The electrostatic latent image on the surface of the photosensitive drum 1 is visualized by being attached with toner by the developing device 16 according to the present invention including the electrostatic transport device according to the present invention. The image is transferred to a transfer sheet (recording medium) 19 fed from the sheet feeding unit 17A or 17B by the sheet feeding roller 18A or 18B by corona discharge of the transfer charger 20. The transfer sheet 19 onto which the visible image has been transferred is separated from the surface of the photosensitive drum 1 by the separation charger 21, transported by the transport belt 22, and passes through the pressure contact portion of the fixing roller pair 23 so that the visible image is transferred. The paper is fixed and discharged to a discharge tray 24 outside the apparatus.
[0028]
On the other hand, the toner remaining on the surface of the photosensitive drum 1 after the transfer is removed by the cleaning device 25, and the charge remaining on the surface of the photosensitive drum 1 is erased by the static elimination lamp 26.
[0029]
Next, the developing device 16 according to the present invention provided with the electrostatic conveyance device according to the present invention in the image forming apparatus will be described with reference to FIG. FIG. 2 is a schematic configuration diagram of the developing device.
The developing device 16 includes a toner hopper unit 31 that stores toner, an agitator 32 that stirs the toner in the toner hopper unit 31, and a charging roller 34 that charges the toner in the toner hop unit 31 and supplies the toner to the toner box unit 33. In addition, the doctor blade 35 disposed in contact with the peripheral surface of the charging roller 34 and the toner in the toner box portion 33 are conveyed by electrostatic force to eject the toner toward the photosensitive drum 1 as a latent image carrier. The electrostatic transport device 36 according to the present invention, a toner recovery member 38 that recovers toner that has not been developed, and toner that transports the toner recovered by the toner recovery member 38 to the toner box unit 33 by electrostatic force. And a reverse conveying member 39.
[0030]
The electrostatic conveyance device 36 is also a first substrate having a conveyance surface 41a that has a front end portion facing the vicinity of the photosensitive drum 1, conveys charged toner by electrostatic force, and ejects the charged toner from the front end portion toward the photosensitive drum 1. An electrostatic transfer substrate 41 and a vibration transfer substrate 42 which has a transfer surface 42a facing the transfer surface 41a of the electrostatic transfer substrate 41 and is also a second substrate to which vibration is applied are provided.
[0031]
In addition, there are provided feeding substrates 43 and 43 for conveying the toner in the toner box portion 33 by electrostatic force between the electrostatic conveying substrate 41 and the vibration conveying substrate 42. One end is bonded to the electrostatic transfer substrate 41 and the vibration transfer substrate 42, and the other end is disposed on the charging roller 34 side.
[0032]
Here, as shown in FIG. 3, the electrostatic transfer substrate 41 and the vibration transfer substrate 42 are arranged with a predetermined gap d with the transfer surfaces 41a and 42a facing each other, and in a direction orthogonal to the transfer direction ( Both end portions in the axial direction of the photosensitive drum 1 are joined via a spacer member 44, and a gap space 46 between the electrostatic conveyance substrate 41 and the vibration conveyance substrate 42 is used as a path through which the toner is conveyed. Thus, the gap d can be maintained by joining and integrating the electrostatic transfer substrate 41 and the vibration transfer substrate 42.
[0033]
The gap (opposite distance) d between the two electrostatic transfer substrates 41 and the vibration transfer substrate 42 at this time is determined in consideration of the toner particle size, charge amount, drive voltage, and the like. It is preferable that the particle diameter is within a range of 2 to 100 times, more preferably within a range of 5 to 25 times the particle size of a certain toner. According to experiments, when the gap (opposite interval) d is less than twice the particle size of the toner, the charged toner is obstructed by the uncharged toner and the conveyance efficiency is lowered. When the diameter exceeds 100 times, the toner conveying effect obtained by vibration flying by the vibration conveying substrate 42 is not sufficiently exhibited.
[0034]
Accordingly, a different example of the first embodiment of the electrostatic transfer substrate 41 constituting the electrostatic transfer device 36 will be described with reference to FIGS. 4 is a schematic cross-sectional explanatory view along the transport direction of an example of the electrostatic transport substrate, FIG. 5 is a schematic cross-sectional explanatory view of another example of the electrostatic transport substrate, and FIG. 6 is an electrostatic diagram of each example. It is plane explanatory drawing explaining the electrode pattern of a conveyance board | substrate.
[0035]
These electrostatic transfer substrates 41 are required in a direction in which a plurality of electrodes 52 for generating a spatial traveling wave electric field intersect with the transfer direction (not limited to orthogonal) on a support substrate 51 which is a rigid support member. An insulating film 53 is formed on the support substrate 51 so as to cover the surface of the driving electrode 52 and between the driving electrodes 52, 52, and a surface layer 54 that is a functional material layer is coated on the surface of the insulating film 53. It is a thing. Note that the example of FIG. 4 and the example of FIG. 5 are the only differences in whether the conveying surface 41a is an uneven surface or a flat surface.
[0036]
As the support substrate 51, an insulating substrate such as a glass substrate, a resin substrate, or a ceramic substrate, or a conductive substrate such as a SUS or silicon substrate is used.
[0037]
Here, when a conductive support substrate is used, it is preferable to ground the conductive substrate. That is, when the support substrate 51 is formed of a conductive substrate, the charge is transferred by applying a high-speed drive pulse for generating a spatial traveling wave electric field to the drive electrode 52, and the toner contacts the electrostatic transfer substrate 41. Since the conductive support substrate is charged as it moves, the electrostatic potential of the conductive support substrate is always constant by grounding the conductive support substrate, and the generation of residual charges can be reduced. The support substrate 51 has a width approximately the same as the width of the photosensitive drum 1.
[0038]
The drive electrode 52 is formed of a conductive material such as Al, Ni—Cr, TiN, polysilicon, or a high-temperature metal film such as Ti, W, or Mo on the support substrate 51 with a thickness of 0.1 to 2 μm. This is formed by patterning into an electrode shape using a semiconductor technique such as a photolithography technique.
[0039]
In this case, it is preferable to form the drive electrode 52 so that the thickness T and the width L in the transport direction have a relationship of T / L = 0.1 or more. For example, the drive electrode 52 is formed with a thickness T = 2 μm and a width L = 10 μm. Thus, by setting the thickness T of the drive electrode 52 to 0.1 or more of the width L, the electric field strength at the adjacent drive electrode 52 increases, and the toner can be efficiently conveyed in a predetermined direction. According to experiments, it was confirmed that the transport amount increases as the thickness of the electrode 52 increases, and the transport amount decreases as the thickness decreases.
[0040]
The thickness T of the drive electrode 52 and the distance R between the electrodes 52 and 52 are R / T = 10 to 3 × 10.³It is preferable to form so that it may become a relationship of R / T = 50-300 so that it may become a relationship of these. For example, when the drive electrode 52 has a thickness T = 2 μm, the drive electrode 52 is formed with an interval R = 100 μm. Thus, the interelectrode distance R of the drive electrode 52 is 10 times to 3 × 10 4 with respect to the thickness of the electrode 52.³By satisfying the relationship, the space traveling electric field generated by the drive electrode 52 and the repulsion / suction of the toner are harmonized, and the toner can be efficiently conveyed.
[0041]
As the insulating film 53, polyimide, SiO₂(Silicon oxide film), Ta₂O₅An inorganic material or an organic material such as (tantalum pentoxide) can be used. The insulating film 53 has a Young's modulus of 30 to 5000 kg / mm.²The dielectric constant is preferably in the range of ε = 2 to 300. By increasing the dielectric constant of the insulating film 53, the drive voltage can be lowered, and the drive recoil and transport speed of particles (toner) are increased.
[0042]
As described above, when the support substrate 51 is a rigid substrate, the Young's modulus of the insulating film 53 is set to 30 to 5000 kg / mm.²The electric field strength between the drive electrodes 52 and 52 is increased by selecting the dielectric constant as follows. In simulation, the film thickness of the insulating film 53 is 1 to 2 μm, and when the dielectric constant ε is about 3 to 20, the electric field strength is large. There was no big difference. The contribution increases when the thickness of the insulating film 53 is 5 to 10 μm or more. Further, when the dielectric constant ε = 500 to 800 as in the BaTiO 3 film, the effect of increasing the electric field strength is great, and the toner movement between the drive electrodes 55 is further efficiently performed.
[0043]
The surface layer 54 is a film having a function of particularly reducing the contact resistance between the transport surface 41a and the charged toner interface, and a material having a critical surface energy Eg of 30 dyne / cm or less is preferable for reducing the contact resistance. For example, it is formed by coating a fluorine resin material such as PTFE or PFA with a thickness of 0.1 to 1 μm. By using the fluororesin, the desired surface layer 54 can be easily formed at low cost.
[0044]
Next, a first embodiment of the vibration transfer substrate 42 will be described with reference to FIG. This figure is a schematic cross-sectional explanatory view along the conveyance direction of the vibration conveyance substrate 42.
The vibration transfer substrate 42 is formed by laminating a vibration generating substrate 62 on a support substrate 61 made of glass, metal, ceramics, or the like, and a transfer surface forming member 63 that is a vibration propagation member that forms a transfer surface on the vibration generating substrate 62. Further, a surface layer 64 is formed on the transport surface forming member 63.
[0045]
The vibration generating substrate 62 is obtained by laminating electrodes 66 and 67 with a ceramic piezoelectric layer 65 interposed therebetween. The transport surface forming member 63 is formed of an insulating or conductive substrate such as silicon, SUS, Ni, polyimide, or the like. The transfer surface forming member 63 includes an inclined surface 63a inclined so as to approach the electrostatic transfer substrate 41 as the first substrate in the transfer direction, and a steep surface 63b having a larger inclination angle than the inclined surface 63a. Are formed in a sawtooth shape in cross-sectional shape.
[0046]
Here, the pitch of the inclined surface 63a and the steep surface 63b of the transport surface forming member 63 is formed to be substantially the same as the line / space (pitch) of the drive electrode 52 of the electrostatic transport substrate 41 or within a range of 10 times or less. If the pitch between the inclined surface 63a and the steep surface 63b exceeds 10 times the pitch of the drive electrode 52, the synergistic effect between the transport by the electrostatic transport substrate 41 and the transport by the vibration transport substrate 42 may not be sufficiently exhibited. is there.
[0047]
Further, the inclination angle θ1 of the inclined surface 63a of the transport surface forming member 63 is preferably in the range of 5 to 60 °, more preferably in the range of 20 to 45 °. The charged toner on the vibration conveyance substrate 42 receives sufficient energy, proceeds in the conveyance direction (from right to left in the figure), and further gives acceleration energy by colliding with the front charged toner. At this time, if the angle θ1 of the inclined surface 63a is smaller than 5 °, the charged toner on the vibration conveyance substrate 42 cannot be sufficiently oscillated to fly, resulting in an increase in driving voltage. On the other hand, when the angle θ1 of the inclined surface 63a is larger than 60 °, when there is a lot of vibration flying toner, the vibration flying toner may collide with the progress toner and take away the progress energy, thereby hindering the efficiency of toner conveyance. .
[0048]
Further, the steep angle θ2 of the steep surface 63b of the transport surface forming member 63 is preferably in the range of 45 to 120 °, and more preferably in the range of 60 to 90 °. This is because, when the steep angle θ2 is larger than 120 °, even if the toner near the steep surface 63b oscillates on the inclined surface 63a of the vibration conveyance substrate 42, it hits the top of the steep surface 63b and falls again onto the inclined surface 63a. As a result, toner stays easily. On the other hand, when the steep angle θ2 is smaller than 45 °, the toner may be deposited on the steep surface 63b, and in any case, the conveyance efficiency may be lowered.
[0049]
Furthermore, the Young's modulus of the conveyance surface forming member 63 is 30 to 15000 kg / mm.²It is preferable to be within the range. Since this conveyance surface forming member becomes a vibration propagation member, by selecting a material having a large Young's modulus, it is possible to propagate the vibration generated in the vibration generation substrate 62 without losing it, thereby improving the conveyance efficiency. be able to.
[0050]
The surface layer 64 is a film having a function of reducing the contact resistance particularly between the transport surface 42a and the toner interface, like the surface layer 53 of the electrostatic transport substrate 41. In order to reduce the contact resistance, a critical surface energy is used. A material having an Eg of 30 dyne / cm or less is preferable. For example, a fluorine resin material such as PTFE or PFA is coated to a thickness of 0.1 to 1 μm. By using the fluororesin, the desired surface layer 64 can be easily formed at low cost. When a conductive substrate is used for the transport surface forming member 63, an insulating film is formed on the surface of the transport surface forming member 63, and the surface layer 64 is formed on the surface of the insulating film. By providing such a surface layer 64, the contact resistance against insulation and toner can be relaxed, and the voltage can be reduced.
[0051]
The electrostatic transfer substrate 41 and the vibration transfer substrate 42 are bonded with the transfer surfaces facing each other via the spacer 44 as described above. Bonding is performed so that the drive electrode 52 of the transfer substrate 41 and the steep surface 63b of the vibration transfer substrate 42 coincide.
[0052]
Next, different examples of the feeding substrate 43 will be described with reference to FIGS. Each figure is a cross-sectional explanatory view along the feeding direction of the feeding substrate 43.
The feed substrate 43 shown in FIG. 8 crosses a plurality of electrodes 72 on the support substrate 71 which is a support member made of a flexible insulating substrate such as a polyimide film, in the same manner as the electrostatic transport substrate 41 (in the transport direction). The insulating film 73 is formed on the support substrate 71 to cover the surface of the drive electrode 72 and the space between the drive electrodes 72 and 72 for generating a space traveling electric field on the support substrate 71. Furthermore, the surface layer 74 is coated on the surface of the insulating film 73.
[0053]
For the flexible support substrate 71, the Young's modulus is 30 to 500 kg / mm as the insulating film 73.²Thus, by using a material having a dielectric constant ε = 2 to 300, the electric field strength between the drive electrodes 72 can be increased. The support substrate 71 may be a conductive substrate formed with an insulating layer. Each feeding substrate 43 is bonded to the support substrate 51 of the electrostatic transfer substrate 41 and the support substrate 61 of the vibration transfer substrate 42.
[0054]
The feed substrate 43 shown in FIG. 9 is formed by laminating a transport surface forming member 73 on a support substrate 71 which is a support member made of a flexible insulating substrate such as a polyimide film, and the vibration transport substrate 42 and the transport surface forming member 73. A similar inclined surface 73a and steep surface 73b are formed, and driving electrodes 72 for generating a spatial electric field on the inclined surface 73a are arranged at a required interval in a direction intersecting (not limited to orthogonal) to the transport direction. The surface of the transport surface forming member 73 is covered with the surface layer 74.
[0055]
In this way, by using the support substrate 71 as a flexible substrate, it is possible to freely bend the device and to make the device compact. In addition, the shape dependency is facilitated and the mounting to the toner box portion or the like is simplified.
[0056]
Next, the toner conveyance operation by the electrostatic conveyance device 36 will be described with reference to FIGS.
First, in the electrostatic transport device 36, as shown in FIG. 10, the three drive electrodes 52, 52, 52 of the electrostatic transport substrate 41 are set as one set, and a three-phase drive voltage ( A driving circuit (driver) 81 for applying driving waveforms Va, Vb, and Vc is provided. The drive waveforms Va, Vb, and Vc output from the drive circuit 81 each have a slight delay time, and the drive waveforms Va, Vb, and Vc all have + potential, −potential, and 0 potential (non-applied). It is a voltage waveform that takes three values. On the other hand, a drive circuit 82 for applying an AC or DC pulse drive waveform for vibrating the vibration generating substrate 62 is provided between the electrodes 66 and 67 of the vibration transfer substrate 42.
[0057]
Here, as shown in FIG. 11, there is positively charged toner T on the electrostatic transport substrate 41, and a plurality of continuous drive electrodes 52 on the electrostatic transport substrate 41 are respectively “−” as indicated by (1). ”,“ + ”,“ 0 ”,“ − ”,“ + ”are applied, and when the positively charged toner T is positioned on the drive electrode 52 of“ 0 ”, the positively charged toner T has“ Since a repulsive force acts between the “+” drive electrode 52 and an attractive force acts between the “−” drive electrode 52 and the right “−” drive electrode 52, the positively charged toner T moves to the “−” drive electrode 52 side. To do.
[0058]
Here, for example, when the three-phase drive voltages Va, Vb, and Vc are applied to the three drive electrodes 52 from the drive circuit 81 in a change pattern as shown in FIG. The voltages applied to the plurality of drive electrodes 52 change as “0”, “−”, “+”, “0”, “−”, respectively, as indicated by (2). Accordingly, no force acts between the drive electrode 52 that has changed from “−” to “0” and the positively charged toner T, and the positively charged toner T has the same relationship as the drive electrode 52 that has changed from “0” to “+”. Since the repulsive force acts between the drive electrode 52 and the drive electrode 52 from “+” to “−”, the positively charged toner T further moves to the “−” drive electrode 52 side.
[0059]
In this way, by changing the potential of the drive waveform applied to the drive electrode 52 and moving the apparent drive waveform, a spatial traveling wave electric field is generated, and the positively charged toner T is attracted to the “−” drive electrode 52 side. The positively charged toner T is transported along the transport surface 41 a of the electrostatic transport substrate 41 because it moves while being moved.
[0060]
Note that the change pattern of the three-phase drive voltages Va, Vb, and Vc applied from the drive circuit 81 to each drive electrode 52 of the electrostatic transport substrate 41 is not limited to the above example. For example, as shown in FIG. Without using “0”, the drive waveform for the two consecutive drive electrodes 52 among the three drive electrodes 52 is “−”, and the drive waveform for the other one drive electrode 52 is “+”. Even in such a case, the positively charged toner T is transported to the electrostatic transport substrate 41 along the transport surface. In addition, without using “−”, the drive waveform for two consecutive drive electrodes 52 among the three drive electrodes 52 is set to “0”, and the drive waveform for the other one drive electrode 52 is set to “+”. The positively charged toner T is transported to the electrostatic transport substrate 41 along the transport surface 41a even if the pattern is to be transferred.
[0061]
Further, as shown in FIG. 14, as the change patterns of the three-phase drive voltages Va, Vb, and Vc, the positively charged toner T is conveyed in the direction opposite to that shown in FIG. Similarly, as shown in FIG. 15, the positively charged toner T is conveyed in the direction opposite to that shown in FIG. 11 even if the change pattern opposite to that shown in FIG. 13 is used. Further, in the case of negatively charged toner, the drive waveform change pattern may be reversed.
[0062]
As described above, the charged toner fed from the feeding substrate 43 by the electrostatic conveyance substrate 41 is conveyed to the photosensitive drum 1 side by electrostatic force by a spatial traveling wave electric field.
[0063]
On the other hand, in the vibration transfer substrate 42, the piezoelectric layer 65 vibrates when an AC or DC pulse drive waveform is applied between the electrodes 66 and 67, and this vibration is propagated to the transfer surface forming member 63 and the transfer surface 42a vibrates. To do. At this time, the vibration transfer substrate 42 is a three-phase AC waveform or a DC pulse synchronized with a drive waveform (three-phase AC waveform) applied to the electrode 52 of the electrostatic transfer substrate 41 applied to the electrodes 66 and 67. And the driving waveform of the electrostatic transfer substrate 41 are synchronized.
[0064]
When the vibration is generated on the conveyance surface 42a of the vibration conveyance substrate 42, the charged toner on the vibration conveyance substrate 42 oscillates and strikes the front toner to give acceleration energy, and the charged toner advances in the conveyance direction. In addition, a gap space 46 is formed between the electrostatic transfer substrate 41 and the vibration transfer substrate 42. When the photosensitive drum 1 rotates, a suction action is generated, and an air flow is generated on the front end side. Since energy in the transport direction is further applied to the charged toner T by this air flow, the charged toner advances in the transport direction also by the air flow.
[0065]
In this way, the charged toner sent between the electrostatic transport substrate 41 and the vibration transport substrate 42 of the electrostatic transport device 36 is transported to the photosensitive drum 1 side by a synergistic effect of electrostatic force and vibration force. A large amount of toner can be efficiently conveyed by conveying the toner by a synergistic effect of electrostatic force and vibration force.
[0066]
In addition, since the vibration transfer substrate has a steep surface with respect to the transfer direction, it is possible to prevent the reverse transfer of toner with a small amount of charge, and the charged toner on the inclined surface can be reliably transferred in the transfer direction. In addition, the transport amount can be made uniform. In addition, although the suction action is caused by the rotation of the photosensitive drum 1 as described above, an air flow in the direction opposite to the conveyance direction may occur in the apparatus due to various factors. In this case, the toner to be conveyed However, since there is a steep surface, the reversely fed toner collides with the steep surface and rebounds in the transport direction, so that the toner can be transported more reliably in the transport direction. it can.
[0067]
Next, the developing operation using the developing device 16 in the image forming apparatus configured as described above will be described with reference to FIG. This figure is an explanatory view of the developing principle of the image forming apparatus.
In this image forming apparatus, the toner in the toner hopper 31 of the developing device 16 is conveyed to the charging roller 34 while being stirred by the agitator 32, and is frictionally charged with the doctor blade 35 by the rotation of the charging roller 34 (counterclockwise in the figure). The toner is charged to a predetermined polarity and sent to the toner box 33.
[0068]
The toner in the toner box portion 32 is conveyed along the feeding substrate 43 by applying the drive waveforms Va, Vb, and Vc as described above to the feeding substrates 43 and 43, and vibrates with the electrostatic conveyance substrate 41. It is sent between the transfer substrate 42. At this time, since the feeding substrates 43 and 43 are bonded to the electrostatic transfer substrate 41 and the vibration transfer substrate 42, the toner is smoothly transferred. Further, by using a substrate having a conveying surface having a sawtooth cross-sectional shape as shown in FIG. 9 as the feeding substrate 43, the reverse feeding of the charged toner due to the air flow is prevented, so that the toner can be more surely statically discharged. It can be sent between the electric transfer board 41 and the vibration transfer board 42.
[0069]
Further, the toners sent between the electrostatic transfer substrate 41 and the vibration transfer substrate 42 are applied with the drive waveforms Va, Vb, and Vc as described above on the electrostatic transfer substrate 41, and the vibration transfer substrate 42 described above. By applying the drive waveform for vibrating the piezoelectric layer 65 as described above, the piezoelectric layer 65 is smoothly transported by a large transport amount along the electrostatic transport substrate 41 and the vibration transport substrate 42, and is opposed to the photosensitive drum 1. Are supplied sequentially from the ejection side.
[0070]
As a result, the ejected positively charged toner T adheres to the negatively charged portion (image portion) on the surface of the photosensitive drum 1 and the latent image on the photosensitive drum 1 is developed. At this time, since the toner conveyance by the electrostatic conveyance substrate 41 and the vibration conveyance substrate 42 is performed efficiently and reliably, supply of a sufficient amount of toner required for development can be ensured.
[0071]
In this case, an AC voltage from an AC power supply 83 is applied to the ejection side of the electrostatic transfer board 41 and the vibration transfer board 42 to generate an AC electric field between the electrostatic transfer board 41 and the tip of the vibration transfer board 42. Then, a toner cloud 84 in which the toner T ejected from between the electrostatic conveyance substrate 41 and the vibration conveyance substrate 42 becomes a cloud state due to an alternating electric field is generated, and the toner is uniformly distributed with respect to the latent image on the photosensitive drum 1. Since it adheres, the image quality is improved.
[0072]
As described above, the latent image carrier is provided with the electrostatic transport device according to the present invention, and the charged toner is transported along the transport surfaces of the electrostatic transport substrate and the vibration transport substrate by a synergistic action by electrostatic force and vibration flight. By providing a developing device for supplying and adhering toner to the toner, it is possible to directly adhere the toner to the surface of the latent image carrier without contact, enabling high image quality development using electrostatic conveyance, and Simplify and reduce costs.
[0073]
Further, toner deterioration is reduced as compared with the case where the developing roller is used as the developing means. That is, normally, the toner is charged by frictional charging, a film is formed on the developing roller together with the magnetic carrier, and the toner electrostatically attached to the carrier is made into a magnetic brush shape, which is brought into contact with the latent image carrier and developed. For this reason, the toner is kneaded by the developing roller and further pulverized into fine powder,₂, TiO₂For example, additives are imprinted on the resin part of the toner, and the characteristics of the toner are deteriorated, resulting in functional failure. In contrast, when the toner is transported by the electrostatic transport substrate as described above, the toner is further pulverized into fine powder, or SiO 2₂, TiO₂Thus, the additive is not imprinted on the resin part of the toner, and the characteristic deterioration is also reduced.
[0074]
Further, since the toner is conveyed to the latent image carrier without rotating the developer carrier such as the developing roller, the toner is not fixed in the developing device, and the toner is carried by the electrostatic force, so that the periphery of the developing unit The toner scattering from the seal portion can be reduced, and the image quality can be improved. Further, since the developing device can be formed compactly without using a special material, the cost can be reduced.
[0075]
In addition, by forming the electrostatic transfer substrate and the vibration transfer substrate in the plate shape as in the above embodiment, the toner transfer means from the toner storage portion to the latent image carrier can be greatly reduced in size. However, it is possible to reduce the size and thickness of the image forming apparatus and the like.
[0076]
Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 2 is a main part explanatory view for explaining a part related to the electrostatic transfer device of the developing device according to the present invention.
In this embodiment, each drive electrode of the electrostatic transport substrate 41 is used as a drive circuit 85 that applies a drive waveform to each of the drive electrodes 52, 52... Of the electrostatic transport substrate 41 of the electrostatic transport device 36 of the developing device 16. 52, three-phase drive waveforms Va1, Vb1, Vc1 of frequency f1, three-phase drive waveforms Va2, Vb2, Vc2 of frequency f2, and three-phase drive waveforms Va3 of frequency f3 (f1> f2> f3). , Vb3, and Vc3, which output drive waveforms of three types of drive frequencies are used.
[0077]
The three-phase drive waveforms Va1, Vb1, and Vc1 of the frequency f1 of the drive circuit 85 are applied to the drive electrodes 52, 52... In the required region on the ejection side of the electrostatic transport substrate 41, and the three-phase drive waveforms of the frequency f2. Va2, Vb2, and Vc2 are applied to the drive electrodes 52, 52,... In the middle portion of the electrostatic transfer substrate 41, and three-phase drive waveforms Va3, Vb3, and Vc3 of the frequency f3 are required on the supply side of the electrostatic transfer substrate 41. The voltage is applied to the electrodes 52, 52. Since other configurations are the same as those of the developing device 16 of the first embodiment, description and illustration are omitted.
[0078]
With this configuration, the frequencies of the drive waveforms Va, Vb, and Vc applied to the drive electrodes 52 of the electrostatic transfer substrate 41 are stepwise from the supply side to the ejection side (in this example, f3, f2, It becomes higher in three stages (f1). Here, since the suction force and the repulsive force acting on the charged toner change in a single time as the frequency of the drive waveform increases, the toner supplied from the supply side of the electrostatic transport substrate 41 is driven by the drive electrode 52. , 52..., 52..., So that the moving speed increases, so that the toner is transported while being accelerated along the transport surface of the electrostatic transport substrate 41 and exposed from the ejection side (one end side). Fly toward the body drum 1.
[0079]
As described above, by giving the drive waveform frequency stepwise, the toner can be accelerated and fly toward the latent image carrier, and the toner can be more reliably attached to the latent image carrier. it can.
[0080]
Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 19 is an explanatory view of the main part of the electrostatic transfer device according to the present invention of the developing device according to the present invention in the image forming apparatus, and FIG. 18 is an enlarged sectional explanatory view of the vibration transfer substrate of the electrostatic transfer device. .
[0081]
The electrostatic transfer device 36 includes the above-described electrostatic transfer substrate 41 and a vibration transfer substrate 92 facing the electrostatic transfer substrate 41. The vibration transfer substrate 92 has substantially the same configuration as that of the vibration transfer substrate 42, but is divided vibrations that are a plurality of independent vibration generating means on the support substrate 61 made of glass, metal, ceramics, or the like along the transfer direction. A generation substrate 93 is arranged, a conveyance surface forming member 63 which is a vibration propagation member for forming a conveyance surface is provided on the divided vibration generation substrate 93, and a surface layer 64 is further formed on the conveyance surface forming member 63. is there.
[0082]
The divided vibration generating substrate 93 is formed by dividing the vibration generating substrate formed by laminating the electrodes 66 and 67 with the piezoelectric layer 65 interposed therebetween as described above, and dividing the divided vibration generating substrate 93. It is a piezoelectric element. The arrangement pitch of the divided vibration generating substrates 92 is substantially the same as the arrangement pitch of the drive electrodes 52 of the electrostatic transfer substrate 41.
[0083]
Then, as shown in FIG. 18, an AC or DC pulse is synchronized with the drive waveforms for the drive electrodes 52 and 52 of the electrostatic transfer substrate 41 from the drive circuit 86 to the electrodes 66 and 67 of each divided vibration generating substrate 93. Is applied, and each divided vibration generating substrate 93 is vibrated at a timing synchronized with the generation of the electric field by the drive electrode 52 of the electrostatic transfer substrate 41. The drive waveform is applied to the electrodes 66 and 67 of each divided vibration generating substrate 93, for example, from one end side of the substrate 93 in the photosensitive drum axial direction with respect to the electrode 67, and to the electrode 68 with respect to the photosensitive of the substrate 93. Perform from the other end side in the body drum axis direction.
[0084]
As described above, the plurality of independent vibration generating means (vibration generating substrates) are arranged in accordance with the arrangement pitch of the drive electrodes 52 of the electrostatic transfer substrate 41 to thereby describe the first embodiment of the image forming apparatus described above. In addition to the effects, the electric field generation by the drive electrode 52 of the electrostatic transfer substrate 41 and the vibration on the vibration transfer substrate 92 side corresponding to the electrode 52 can be more reliably matched, and the transfer efficiency is further improved.
[0085]
Next, a fourth embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. 20 is an explanatory view of a main part of the electrostatic transfer device according to the present invention of the developing device according to the present invention in the image forming apparatus, and FIG. 20 is an enlarged sectional explanatory view of a vibration transfer substrate of the electrostatic transfer device. .
[0086]
The electrostatic transfer device 36 includes the above-described electrostatic transfer substrate 41 and the vibration transfer substrate 102 opposed thereto. This vibration transfer substrate 102 has substantially the same configuration as the vibration transfer substrate 92, but a plurality of independent divided vibration generation substrates 93 are arranged along the transfer direction on a support substrate 61 made of glass, metal, ceramics, or the like. Then, a conveyance surface forming member 63 that is a vibration propagation member that forms a conveyance surface is provided on the divided vibration generating substrate 93, and a drive electrode 103 is formed in the vicinity of the top of the inclined surface 63a of the conveyance surface forming member 63. And coated with the surface layer 64.
[0087]
As shown in FIG. 20, the drive circuit 86 synchronizes the drive waveforms for the drive electrodes 52 and 52 of the electrostatic transfer substrate 41 with respect to the electrodes 66 and 67 of the divided vibration generation substrate 93 as described above. Each divided vibration generating substrate 93 is vibrated at a timing synchronized with the generation of an electric field by the drive electrode 52 of the electrostatic transfer substrate 41 by applying an AC or DC pulse.
[0088]
At the same time, similarly to the drive electrode 103 of the electrostatic transfer substrate 41, the drive electrode 103 of the vibration transfer substrate 102 is set as a set of three drive electrodes 103, 103, 103 from the drive circuit (driver) 104. Three-phase drive voltages (drive waveforms) Va, Vb, and Vc are applied to the drive electrodes 103, respectively. Thereby, the vibration conveyance substrate 102 can perform toner conveyance by electrostatic force as well as toner conveyance by vibration, and can further increase the conveyance amount and improve the conveyance efficiency.
[0089]
Here, another example of the vibration transfer substrate that can be used in each of the above-described embodiments will be described with reference to FIG. This figure is an enlarged cross-sectional explanatory view of a main part along the conveyance direction of the vibration conveyance substrate.
The vibration transfer substrate 112 has the same configuration as the vibration transfer substrate 42 described above, but an inclined surface 63a that approaches the electrostatic transfer substrate 41 toward the transfer direction formed on the transfer surface forming member 63, and the inclined surface 63a. The continuous portion 63c on the bottom side with the steep surface 63b having a larger inclination angle than that is formed in a curved shape.
[0090]
Thus, by forming the bottom side continuous portion 63c of the inclined surface 63a and the steep surface 63b in a curved surface shape, it is possible to prevent toner from staying in the continuous portion 63c, thereby improving the conveyance efficiency and smoothing. Transport can be performed. Here, the vibration transfer substrate 112 has the same configuration as that of the vibration transfer substrate 42, but can also have the same configuration as the vibration transfer substrates 92 and 102.
[0091]
Next, an image forming apparatus according to a fifth embodiment of the invention will be described with reference to FIGS. FIG. 23 is an explanatory view of a main part of the electrostatic transfer device according to the present invention of the developing device according to the present invention of the image forming apparatus, and FIG. 24 is an enlarged cross-sectional explanatory view of a counter substrate of the electrostatic transfer device.
[0092]
The electrostatic transfer device 136 includes the above-described electrostatic transfer substrate 41 and a counter substrate 142 that is a second substrate facing the electrostatic transfer substrate 41. The counter substrate 142 includes an inclined surface 153a approaching a support substrate 151 made of glass, metal, ceramics, or the like toward the electrostatic transfer substrate 41 serving as a transfer surface 153, and a steep surface 153b having a larger inclination angle than the inclined surface 153a. In addition, a continuous portion 153c on the bottom side of the inclined surface 153a and the steep surface 153b is formed in a curved shape, and a surface layer 154 is further formed on the transport surface 153.
[0093]
Here, it is preferable that the pitch between the inclined surface 153a and the steep surface 153b is substantially the same as the line / space (pitch) of the drive electrode 52 of the electrostatic transfer substrate 41 or within a range of 10 times or less. If the pitch between the inclined surface 153a and the steep surface 153b exceeds 10 times the pitch of the drive electrode 52, the toner recoil effect by the steep surface 153b may be diminished and the reverse feed prevention effect may be reduced.
[0094]
Further, the inclination angle θ3 of the inclined surface 153a is preferably in the range of 5 to 60 °, more preferably in the range of 20 to 45 °. The charged toner on the counter substrate 142 receives sufficient energy and proceeds in the transport direction (from right to left in the figure), and further gives acceleration energy by colliding with the forward charged toner. This is because when the angle θ3 is small, the electrostatic force due to the electric field from the electrostatic transport substrate 41 cannot be obtained, and the charged toner on the counter substrate 142 cannot be transported sufficiently, leading to an increase in driving voltage. . On the other hand, when the angle θ3 of the inclined surface 153a is large, the toner on the counter substrate 142 falls in the bottom direction of the inclined surface 153a and hinders the efficiency of toner conveyance.
[0095]
The surface layer 154 is a film having a function of reducing the contact resistance between the transfer surface 153 and the toner interface, in particular, like the surface layer 54 of the electrostatic transfer substrate 41. In order to reduce the contact resistance, the critical surface energy is reduced. A material having an Eg of 30 dyne / cm or less is preferable. For example, a fluorine resin material such as PTFE or PFA is coated to a thickness of 0.1 to 1 μm.
[0096]
Similar to the electrostatic transfer substrate 42 and the vibration transfer substrate 42 described above, the electrostatic transfer substrate 41 and the counter substrate 142 are bonded to each other with the transfer surfaces facing each other via a spacer, and the gap space 146 is joined to the toner. It is used as a passage to convey.
[0097]
The gap (opposite distance) d between the two electrostatic transfer substrates 41 and the counter substrate 142 at this time is determined in consideration of the toner particle size, charge amount, drive voltage, and the like, but is a powder to be transferred. It is preferable that the toner particle diameter is in the range of 2 to 100 times, more preferably in the range of 5 to 25 times. According to experiments, when the gap (opposite interval) d is less than twice the particle size of the toner, the charged toner is obstructed by the uncharged toner and the conveyance efficiency is lowered. When the diameter exceeds 100 times, the toner conveying effect by the counter substrate 142 cannot be sufficiently obtained.
[0098]
In the electrostatic transport device 136 configured as described above, the charged toner is transported by the electrostatic force of the electrostatic transport substrate 41 as described above. At the same time, a suction action is generated by the rotation of the photosensitive drum 1 facing the tip of the electrostatic transport device 136, and a wind flow in the toner transport direction is generated between the electrostatic transport substrate 41 and the counter substrate 142. Due to this flow and the electrostatic force from the electrostatic transport substrate 41, the charged toner receives sufficient energy and proceeds in the transport direction (from right to left in FIG. 23), and further collides with the forward charged toner. It is made to convey with acceleration energy. Further, since the steep surface 153b is provided, the toner that collides with the steep surface is bounced off in the transport direction by the energy at the time of collision, and moves in the transport direction together with other charged toner, thereby preventing the toner from being reversely fed. The
[0099]
Thus, the second substrate is not a vibration transfer substrate, and the cross-sectional shape having an inclined surface and a steep surface is a counter substrate having a saw-tooth shape, as compared with the case of a simple electrostatic transfer substrate alone. Therefore, it is possible to prevent the toner from being reversely fed due to the air flow in the reverse feeding direction, and to efficiently carry the toner in the forward direction (conveying direction).
[0100]
Then, the toner can be directly adhered to the surface of the latent image carrier by contact, and high image quality development using electrostatic conveyance becomes possible, and the apparatus is simplified and the cost can be reduced. Further, the toner can be transported without using mechanical power such as a developing roller, and the toner can be transported by using a plate-like electrostatic transport substrate or counter substrate as in this embodiment. The toner transfer means between the storage unit and the latent image carrier can be greatly reduced in size, and the image forming apparatus capable of forming an image of high image quality can be reduced in size and thickness.
[0101]
Next, a sixth embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 25 is an explanatory view of a main part of the electrostatic transfer device according to the present invention of the developing device according to the present invention of the image forming apparatus, and FIG. 26 is an enlarged cross-sectional explanatory view of a counter substrate of the electrostatic transfer device.
[0102]
The electrostatic transfer device 136 includes the above-described electrostatic transfer substrate 41 and a counter electrostatic transfer substrate 162 that is a second substrate facing the electrostatic transfer substrate 41. The counter electrostatic transfer substrate 162 has the same configuration as that of the counter substrate 142 of the fifth embodiment, but includes a drive electrode 163 for generating a spatial traveling wave electric field substantially at the top of the inclined surface 153a of the transfer surface 153. Provided. A three-phase AC waveform synchronized with the drive waveform for the drive electrode 52 of the electrostatic transfer substrate 41 is also applied to the drive electrode 163 of the counter electrostatic transfer substrate 162 by the drive circuit 164 to generate a spatial traveling wave electric field.
[0103]
As a result, the charged toner is transported by receiving electrostatic force between the upper and lower electrostatic transport substrates 41 and the counter electrostatic transport substrate 162, and also receives energy from the suction action of the photosensitive drum 1, and more. It is possible to carry with the carry amount.
[0104]
Next, seventh and eighth embodiments of the image forming apparatus according to the present invention will be described with reference to FIGS. 27 and 28. FIG. FIGS. 2A and 2B are explanatory views of a main part of the electrostatic conveyance device according to the present invention of the developing device according to the present invention of the image forming apparatus of each embodiment.
The electrostatic conveyance device 176 constituting the developing device in the image forming apparatus according to the seventh embodiment shown in FIG. 27 is configured such that the toner path is between the vibration conveyance substrate 102 according to the fourth embodiment and the vibration conveyance substrate 102. A lid member 178 forming 177 is provided, and the vibration transfer substrate 102 and the lid member 178 are joined with a predetermined gap as in the above embodiments.
[0105]
In this embodiment, toner is transported by electrostatic force and vibration of the vibration transport substrate 102 and forward air flow by the photosensitive drum 1. Even in this case, since the reverse flow of the toner due to the air flow in the apparatus is prevented, a sufficient amount of toner can be efficiently conveyed as compared with the case where the toner is conveyed by simple electrostatic force and vibration. Can do.
[0106]
The electrostatic transfer device 186 constituting the developing device in the image forming apparatus according to the eighth embodiment shown in FIG. 28 includes the counter electrostatic transfer substrate 162 according to the sixth embodiment described above and the counter electrostatic transfer substrate 162. A cover member 188 that forms a toner passage 187 is provided, and the counter electrostatic transfer substrate 162 and the cover member 188 are joined with a predetermined gap as in the above embodiments.
[0107]
In this embodiment, toner is transported by the electrostatic force of the counter electrostatic transport substrate 162 and the forward air flow by the photosensitive drum 1. Even in this case, since the reverse feeding of the toner due to the air flow in the apparatus is prevented, a sufficient amount of toner can be efficiently conveyed as compared with the case where the toner is conveyed with a simple electrostatic force. .
[0108]
Next, another example of the developing device according to the present invention will be described with reference to FIG. This developing device develops the latent image on the photosensitive drum 1 using a developing roller 191 as developing means, and the developing roller 191 is supplied with toner by using the feeding substrate 43 shown in FIG. I try to send it in.
[0109]
By supplying the toner to the developing roller 191 using the feeding substrate 43 in this way, the influence of the wind pressure due to the rotation of the developing roller 191 is reduced, and the toner can be reliably supplied to the developing roller 191. The size of the developing device can be reduced by performing the electric conveyance.
[0110]
In each of the above embodiments, the electrostatic conveyance device that conveys toner with an electrostatic force has been described. However, the present invention can be similarly applied to a device that conveys powder other than toner.
[0111]
【The invention's effect】
  As described above, according to the electrostatic transfer device of the present invention, the first substrate having a plurality of electrodes for generating an electric field for moving the powder with an electrostatic force along the transfer surface, and the first substrate. A second substrate having an inclined surface and a steep surface whose inclination angle is steeper than that of the inclined surface, the second substrate having a substantially serrated shape. As a means for vibrating the two substrates, a divided vibration generating substrate formed by dividing a vibration generating substrate having a piezoelectric material layer and an electrode sandwiching the piezoelectric material layer into divided grooves is provided, and the electrode pitch of the divided vibration generating substrate is the same as that of the first substrate. It is substantially the same as the electrode pitch, and the electrode of the divided vibration generating substrate and the electrode of the first substrate are arranged to face each other, and the drive of the electrode of the first substrate with respect to the electrode of the divided vibration generating substrate is driven AC or DC in sync with waveform By applying a pulse vibrates the split vibration generating substrateConfiguredTherefore, the reverse feeding of the powder is prevented and the powder can be reliably and efficiently conveyed.
[0112]
  here,A conveying surface forming member that is a vibration propagation member that forms a conveying surface on the divided vibration generating substrate is provided, and an electrode is provided near the top of the inclined surface of the conveying surface forming member, and the inclined surface of the conveying surface forming member is provided. By adopting a configuration in which the drive waveform is applied to the upper electrode, the conveyance amount can be increased and the conveyance efficiency can be improved. Also,The inclined surface of the second substrate and the bottom side continuous portion of the steep surface form a curved surface shape.By configuringPrevents stagnation of powder in the continuous part and improves powder transfer efficiency..
[0123]
The developing device according to the present invention is a developing device that develops the latent image on the latent image carrier by attaching toner onto the latent image carrier, and includes the electrostatic conveyance device according to the present invention. Since the tip of the electrostatic transport substrate of the electrostatic transport device faces the latent image carrier, the toner transport necessary for development can be performed with a stable transport amount, and the development quality is improved. Further, the developing device can be reduced in size.
[0124]
The developing device according to the present invention is a developing device that develops the latent image on the latent image carrier by attaching toner onto the latent image carrier, and includes the electrostatic transport device according to the present invention. Since the toner is fed by the electrostatic conveyance device to the developing means for attaching the toner to the latent image carrier, the toner necessary for development can be supplied with a stable conveyance amount, and the development quality is improved. In addition, the developing device can be reduced in size.
[0125]
According to the image forming apparatus of the present invention, the image forming apparatus includes a developing device that develops the latent image on the latent image carrier by attaching toner onto the latent image carrier, and the developing device according to the present invention. Since the apparatus is provided, an image can be formed with high image quality and the entire apparatus can be miniaturized.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram illustrating an example of a developing device of the image forming apparatus.
FIG. 3 is an explanatory side view of an electrostatic transfer device of the developing device.
FIG. 4 is a schematic cross-sectional explanatory view along the transport direction showing an example of an electrostatic transport substrate in the electrostatic transport apparatus.
FIG. 5 is a schematic cross-sectional explanatory view along the transport direction showing another example of the electrostatic transport substrate in the electrostatic transport apparatus.
FIG. 6 is an explanatory plan view of the electrostatic transfer substrate.
FIG. 7 is a schematic cross-sectional explanatory view along the transport direction showing an example of a vibration transport substrate in the electrostatic transport device.
FIG. 8 is a schematic cross-sectional explanatory view along the transport direction showing an example of a feeding substrate in the electrostatic transport apparatus.
FIG. 9 is a schematic cross-sectional explanatory view along the transport direction showing another example of the feeding substrate in the electrostatic transport apparatus.
FIG. 10 is an explanatory diagram illustrating a driving unit of the electrostatic transfer device
FIG. 11 is an explanatory diagram for explaining the principle of powder conveyance by the electrostatic conveyance device.
FIG. 12 is an explanatory diagram for explaining an example of a change pattern of a drive waveform applied to a drive electrode of the electrostatic transfer device
FIG. 13 is an explanatory diagram for explaining another example of a change pattern of a drive waveform applied to a drive electrode of the electrostatic transfer device
FIG. 14 is an explanatory diagram for explaining still another example of a change pattern of a drive waveform applied to a drive electrode of the electrostatic transfer device
FIG. 15 is an explanatory diagram for explaining still another example of a change pattern of a drive waveform applied to the drive electrode of the electrostatic transfer device
FIG. 16 is an explanatory diagram for explaining the principle of the developing operation in the image forming apparatus.
FIG. 17 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a second embodiment of the present invention.
FIG. 18 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a third embodiment of the present invention.
FIG. 19 is an enlarged explanatory view of a main part along the conveyance direction of the vibration conveyance substrate of the electrostatic conveyance device.
FIG. 20 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a fourth embodiment of the present invention.
FIG. 21 is an enlarged explanatory view of a main part along the conveyance direction of the vibration conveyance substrate of the electrostatic conveyance device.
FIG. 22 is a main part enlarged explanatory view along the transport direction for explaining another example of the vibration transport substrate.
FIG. 23 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a fifth embodiment of the present invention.
FIG. 24 is an enlarged explanatory view of a main part along the transfer direction of the counter substrate of the electrostatic transfer device.
FIG. 25 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a sixth embodiment of the present invention.
FIG. 26 is a main part enlarged explanatory view along the transport direction of the counter electrostatic transport substrate of the electrostatic transport apparatus.
FIG. 27 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to a seventh embodiment of the present invention.
FIG. 28 is an explanatory view of a main part of an electrostatic transfer device portion of an image forming apparatus according to an eighth embodiment of the present invention.
FIG. 29 is a main part explanatory view showing another example of a developing device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum (latent image carrier), 5, 8 ... Scanning optical system, 13 ... Polygon mirror, 15 ... Charging device, 16 ... Developing device, 17A, 17B ... Paper feeding unit, 20 ... Transfer charger, 21 ... Separation charger 23 ... Fixing roller pair 31 ... Powder hopper part 34 ... Charging roller 36 ... Electrostatic transfer device 41 ... Electrostatic transfer substrate 42, 92, 102, 112 ... Vibration transfer transfer substrate 43 ... Feed substrate 51 ... Support substrate 52 ... Drive electrode 53 ... Insulating film 54 ... Surface layer 61 ... Support substrate 62 ... Vibration generating substrate 63 ... Conveying surface forming member 63a ... Inclined surface 63b ... Steep surface , 63c ... continuous portion, 64 ... surface layer, 93 ... divided vibration generating substrate, 103 ... electrode, 142 ... counter substrate, 153a ... tilted surface, 153b ... steep surface, 153c ... continuous portion, 162 ... counter electrostatic transfer substrate.

Claims (6)

In an electrostatic transport device that transports powder with electrostatic force,
A first substrate having a plurality of electrodes for generating an electric field for moving the powder with electrostatic force along the conveying surface;
A second substrate that is disposed to face the first substrate with a gap, and has a sloped surface and a steep surface with a steeper angle than the sloped surface.
The second substrate includes a divided vibration generating substrate formed by dividing a vibration generating substrate having a piezoelectric material layer and an electrode sandwiching the piezoelectric material layer by dividing grooves as means for vibrating the second substrate,
The electrode pitch of the divided vibration generating substrate is substantially the same as the electrode pitch of the first substrate, and the electrode of the divided vibration generating substrate and the electrode of the first substrate are arranged to face each other,
An electrostatic system characterized in that the divided vibration generating substrate is vibrated by applying an AC or DC pulse to the electrode of the divided vibration generating substrate in synchronization with a driving waveform for the electrode of the first substrate. Conveying device. The electrostatic transfer apparatus according to claim 1, further comprising: a transfer surface forming member that is a vibration propagation member that forms a transfer surface on the divided vibration generating substrate, and further substantially the top of the inclined surface of the transfer surface forming member. An electrostatic transfer apparatus, wherein an electrode is provided in the vicinity, and a drive waveform is applied to an electrode on an inclined surface of the transfer surface forming member. 3. The electrostatic transfer apparatus according to claim 1 , wherein an inclined surface of the second substrate and a bottom side continuous portion of the steep surface have a curved surface shape. 4. In the developing apparatus by adhering toner on the latent image bearing member to develop the latent image on the latent image bearing member comprises an electrostatic transport device according to any one of claims 1 to 3, the electrostatic transporting device a developing device tip of the electrostatic transporting substrate is characterized in that the face in the vicinity of the latent Zo担 bearing member. 4. A developing device for developing a latent image on a latent image carrier by attaching toner on the latent image carrier, comprising: the electrostatic transport device according to claim 1; A developing device characterized in that the toner is fed by the electrostatic conveying device to a developing means to be adhered to a carrier. 5. An image forming apparatus comprising a developing device for developing a latent image on a latent image carrier by attaching toner on the latent image carrier, wherein the developing device is the developing device according to claim 4. Image forming apparatus.

Images