JP2006308804A - Development device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development device capable of steady development in which toner stay and accumulation are reduced, and to provide a process cartridge and an image forming apparatus. <P>SOLUTION: A skeleton conveyance member 1 is formed such that three skeleton electrode members 11 are disposed in layers, in a direction perpendicular to the direction of toner conveyance via insulation members 15, 15 disposed at both the ends. Each of the skeleton electrode members 11 forms a plurality of electrode lines 12 at prescribed intervals with spaces 13 between them, such that a structure in which the electrode lines 12 of the respective layers are disposed spatially in layers. Toner is conveyed via a space 14 defined between the surface of the skeleton electrode member 11, forming the uppermost layer and the skeleton electrode member 11 forming each layer. A skeleton conveyance member 111 for development and a skeleton conveyance member 112 for return, which are constructed from this skeleton conveyance member 1, are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus, and more particularly to a developing device, a process cartridge, and an image forming apparatus that convey toner by a traveling wave electric field.

  As various image forming apparatuses such as printers, facsimiles, copying machines, plotters, printer / fax / copier multifunction machines, etc., the image carrier is charged to form an electrostatic latent image, and the electrostatic latent image is colored. And a toner image (including transfer material, paper, recording paper, intermediate transfer body, etc.) by developing a toner image (hereinafter referred to as “toner” or “toner particles”). An image forming apparatus using an electrophotographic process for transferring to (.) Is known.

In such an image forming apparatus, as described in Patent Documents 1 and 2, an electrostatic transport substrate that transports toner by a traveling wave electric field (also referred to as a phase shift electric field or a transport electric field) is provided. A developing device that develops by ejecting toner from the front end portion of the electric transport substrate toward the latent image on the image carrier, and hops the toner on the electrostatic transport substrate as described in Patent Document 3. There is known a developing device for developing a latent image on an image carrier.
JP 2003-098826 A JP 2002-240943 A JP 2003-043806 A

Further, as devices for electrostatically transporting toner, those described in Patent Documents 4 to 8 are known.
JP-A-8-149859 JP 2003-098826 A JP 2004-157259 A JP 2001-139144 A JP 2004-219768 A

  As described in Patent Documents 1 to 3 and the like, conventional toner conveying members used in such conventional developing devices that electrostatically convey toner are placed on members such as glass substrates, FPCs, and PCBs. A toner transport substrate (member) that generates a traveling wave electric field for transporting toner is formed by forming electrodes and laminating them.

  However, in the above-described conventional toner conveying member, if the surface material of the conveying member has a problem in charging or a combination of charging sequences with respect to toner charging, a Coulomb force acts between the toner and the surface of the conveying member, and adsorption However, there is a problem that fixing or toner charge deterioration occurs. In addition, the conveyance member is sensitive to the humidity of the environmental atmosphere. When the humidity exceeds 50%, there is a problem that the fixation due to the liquid cross-linking force increases and the toner is fixed to the surface of the conveyance member and cannot be conveyed.

  In addition, particularly when low-charged or uncharged toner is supplied to the surface of the conveying member, it cannot follow the electric field phase shift in the conveying electric field and stays on the surface of the conveying member. There is also a problem that the conveyance efficiency is remarkably lowered or the conveyance becomes impossible.

  Therefore, when such a transport member is used in the developing device of the image forming apparatus, if toner adheres to or adheres to the transport member, the toner accumulates without being transported and cannot be developed when used in the developing device. It will be accompanied by the problem. Further, since only the upper surface (2π) of the conveying member is conveyed, there is a limit in the amount of toner conveyance, and there is a problem that it becomes impossible to cope with high-speed development.

  SUMMARY An advantage of some aspects of the invention is that it provides a developing device, a process cartridge, and an image forming apparatus capable of performing stable development with reduced toner retention and accumulation.

  In order to solve the above problems, the developing device according to the present invention conveys toner by a conveying electric field formed by applying a multiphase voltage to a plurality of electrodes arranged at a predetermined interval, and carries an image. In a developing device for developing a latent image of a body, at least two skeleton conveying members in which electrode lines constituting the electrode are spatially stacked and arranged in a skeleton structure are provided, one for developing the toner The developing skeleton conveying member that conveys in the forward direction, and the other one is a returning skeleton conveying member that conveys the toner that did not contribute to development in the reverse direction.

  Here, it is preferable that a bias electrode member to which a bias voltage for suppressing scattering of toner is applied to face the skeleton conveying member is provided. In this case, it is preferable that an opening is formed in the bias electrode member facing the return skeleton transport member.

  Preferably, an electrode member to which a bias voltage having the same polarity as that of the charged toner is applied is provided on the toner inlet portion side of the return skeleton conveying member. Preferably, an electrode member to which a bias voltage having the same polarity as that of the charged toner is applied is provided on the toner outlet portion side of the return skeleton conveying member.

  Further, a pulsed voltage that causes the charged toner to repel and fly larger than the other electrode wire layers may be applied to the electrode wire layer on the developing skeleton carrying member side of the return skeleton carrying member. preferable. In this case, the pulse voltage applied to the electrode wire layer on the developing skeleton transfer member side of the return skeleton transfer member is higher than the pulse voltage applied to the other electrode wire layers. Is high, or the time for attracting the toner is long or the frequency is high.

  Further, it is preferable that a toner outlet portion of the return skeleton conveying member is close to the developing skeleton conveying member side. Furthermore, it is preferable that an insulating protective film is formed on the surface of the electrode wire of the skeleton transport member. Furthermore, it is preferable to adjust a bias voltage applied to a toner supply member that supplies toner to the developing skeleton conveying member based on a toner density detection result. Further, it is preferable that the image carrier is disposed to face the transport surface of the developing skeleton transport member.

  A process cartridge according to the present invention includes an image carrier, a charging unit, a cleaning unit, and a developing device according to the present invention, and is configured to be detachable from the image forming apparatus main body. .

  An image forming apparatus according to the present invention includes one or a plurality of developing devices according to the present invention or process cartridges according to the present invention.

  According to the developing device of the present invention, development and toner return are performed using a plurality of skeleton conveying members in which electrode wires constituting the electrode are spatially stacked and arranged in a skeleton structure, so that toner retention and accumulation are reduced. In addition, the toner conveyance amount can be increased and the toner can be circulated, so that stable development can be performed.

  According to the process cartridge and the image forming apparatus according to the present invention, since the developing device according to the present invention is provided, the retention and accumulation of toner can be reduced, the toner conveyance amount can be increased, and the toner can be circulated. , Stable development can be performed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first example of a skeleton transport member used in the developing device according to the present invention will be described with reference to FIGS. 1 is an explanatory plan view of the skeleton conveying member, FIG. 2 is an enlarged sectional explanatory view taken along the line AA of FIG. 1, and FIG. 3 is an explanatory side view of the skeleton conveying member.

  This skeleton conveying member 1 is formed by laminating three skeleton electrode members 11 at both ends in a direction crossing the toner conveying direction via insulating members 15 and 15. The skeleton electrode member 11 is formed by forming a plurality of electrode wires 12 with gaps 13 at predetermined intervals. Then, the skeleton electrode member 11 is laminated on both ends via insulating members 15 and 15 so that the electrode wires 12 of each layer are spatially laminated (via the space). That is, the skeleton transport member 1 has a skeleton structure in which the space 14 is interposed between the electrode wires 12 of the skeleton electrode members 11 of each layer. In this case, if the voltage applied to the electrode wire 12 is n-phase (here, three-phase), the three skeleton electrode members 11 are laminated by shifting the gap 13 by 1 / n in the transport direction. A phase-shifting electric field can be generated.

  Specifically, for example, the electrode wire 12 and the space 13 are formed by etching a thin plate (foil) such as SUS304, 303, 306, 316, Ni and its alloys, or a hypertensive alloy, or by electroforming. Alternately formed skeleton electrode members 11 can be produced. In this case, for example, using SUS304 having a thickness of 100 μm, the electrode line 12 was formed to have a line width of 100 μm, and the gap 13 was formed to have a width of 500 μm.

  Then, for example, a polyimide plate having a thickness of 100 μm is sandwiched between the both ends of the skeleton electrode member 11 on which the electrode wires 12 are formed in the shape of a slat or sag, and a skeleton electrode member 11 of the next layer is formed to a thickness of 500 μm. The gap 13 is joined at a position of 100 μm, and similarly, a polyimide plate with a thickness of 100 μm as an insulating member 15 is sandwiched, and the skeleton electrode member 11 of the next layer is joined at a position of 100 μm with a gap of 500 μm. Three layers of skeleton electrode members 11, 11, and 11 are joined.

  Accordingly, in a three-dimensional manner, when the lowermost skeleton electrode member 11 is the first layer in the figure, the reference electrode wire 12 of the first skeleton electrode member 11 is used as a reference. The electrode wire 12 of the skeleton electrode member 11 in the second layer is located at a position shifted by 200 μm in the transport direction and 100 μm in the height direction with respect to 12, and further 400 μm in height in the transport direction with respect to the reference electrode wire 12 The electrode line 12 of the skeleton electrode member 11 in the third layer is positioned at a position shifted by 300 μm in the direction.

  In the skeleton transport member 1 configured in this way, as shown in FIG. 4, the voltage application means 2 applies n-phase (here, three-phase) pulse voltages Va, Vb, Vc to each skeleton electrode member 11. As a result, a traveling wave electric field is formed, and the charged toner T is conveyed in the conveying direction. The principle of transporting charged toner by a traveling wave electric field will be described later.

  At this time, since the skeleton transport member 1 has a skeleton structure in which the electrode wires 12 are spatially stacked, the spaces 14 and 14 between the skeleton electrode members 11 also serve as toner transport spaces, and the surface of the uppermost skeleton electrode member 11. The toner is transported through the space 14 between the uppermost skeleton electrode member 11 and the space 14 between the lower skeleton electrode member 11. That is, while the conventional method is to convey only the upper surface (2π) of the conveying member, it can be conveyed by 4π including the interelectrode space (the lower surface of the electrode).

Therefore, a conventional substrate made of an insulating material such as a glass substrate, a resin substrate or a ceramic substrate, or a substrate made of a conductive material such as SUS, and an insulating film such as SiO ₂ formed thereon, a polyimide film, etc. Compared to the case where electrodes are formed on a substrate made of a material that can be deformed flexibly, the toner conveyance space (conveyance path) increases three times, and the toner conveyance amount per unit time increases. be able to.

  Further, the poorly charged toner can be separated from the gap between the electrode wires and selectively transport the properly charged toner. Furthermore, since the skeleton transport member 1 has a skeleton structure in which the electrode wires 12 are spatially arranged, there is no member to which toner adheres and adheres between the electrode wires 12, and the electrode wires 12 depend on the driving frequency. Depending on the applied voltage and width (length), a vibration of 0.1 μm or more (a vibration of about 50 μm was confirmed) occurred depending on the applied voltage and width (length). Even if a part of the toner adheres to the wire, it is peeled off by vibration, and the toner can be prevented from adhering and fixing.

  In the manufacturing example described above, the electrode wires 12 have a pitch of 200 μm and the distance between the wires is 100 μm. The electric field between lines when a driving voltage of 400 V was applied was 4 kV / mm. When the charged toner adheres, a higher electric field strength is required at a limit potential for isolating the charged toner. In particular, the adhesive strength becomes strong at high temperature and high humidity, and 6 kV / mm or more is required. In this case, by coating the surface of the electrode wire 12 with a water repellent material or an inorganic oxide film with little adsorbed water, the adhesion force of the toner can be reduced and the peeling electric field can be lowered.

  Further, the skeleton electrode member can be manufactured by an inexpensive conventional technique without applying an expensive semiconductor technique, and the cost can be reduced. Note that the electrode line pitch, electrode line width, gap between the upper and lower electrode lines, etc. of the skeleton electrode member are not limited to the above description, and the drive voltage for generating the phase-shift electric field is not limited to the above example. is not.

Here, different examples of the structure of the electrode wire 12 that further reduces the adhesion of the toner to the electrode wire 12 will be described with reference to FIGS. 5 and 6 are enlarged cross-sectional explanatory views of the main part of the electrode wire 12.
In the example shown in FIG. 5, the electrode wire 12 has a cross-sectional shape along the transport direction, and has a shape having tapered surfaces 12 a and 12 b facing at the upper and lower sides in the transport direction at least at the end facing the transport direction. In the example illustrated in FIG. 6, the electrode wire 12 has a cross-sectional shape along the transport direction, and has a shape having a tapered surface 12 a facing upward in the transport direction at least at an end facing the transport direction.

  By making the cross-sectional shape of the electrode wire 12 into such a shape, as shown in FIG. 5 or FIG. 6, the toner T that has been transported collides with the taper surfaces 12a and 12b and recoils to the upper side in the transport direction. Or it will go to the lower side and it will become difficult to adhere and adhere to the electrode wire 12 compared with the case where the edge part of the electrode wire 12 is formed in the flat surface.

Next, a configuration for preventing an electrical contact short circuit between the electrode wires 12 of the skeleton electrode member 11 will be described.
When applying the multi-phase driving voltage to the electrode wire 12 of the skeleton electrode member 11 to convey the toner as described above, the skeleton electrode member 11 repeats suction and repulsion between the skeleton electrode members 11 for each driving frequency by the electric field during electric field driving, There is a natural frequency that depends on the stiffness and structure of the electrode material, and the corresponding self-excited vibration amplitude is generated. At this time, depending on the magnitude and inertia of the amplitude, depending on the gap between the skeleton electrode members 11 facing each other, there is a possibility that some contact may occur between the electrode wires 12 and 12 and an electrical contact may occur.

To prevent this, an organic material (fluorine-based high-insulating material ^{(1 * 10E 9 ~16Ω / cm} ) Hardness (Vickers hardness of 40 or higher), silicone, acrylic, polyimide, urea, polycarbonate resins Using an inorganic material (a simple substance such as SiO ₂ , ZrO ₂ , BaTiO ₃ , Ta ₂ O ₅ , Si ₃ N ₄ , Y ₂ O _3, or a composite material thereof), an immersion method, a spray method, or A surface protective layer (protective film) is formed on the surface of the skeleton electrode member 11 by a method of leaving a masking resist material by an etching method, a sputtering method, a CVD (vapor phase growth) method, an LP (low temperature) CVD method, etc. To do. Thus, the protective film can prevent the skeleton electrode member 11 from being electrically short-circuited at the time of contact even if the self-excited vibration amplitude at the time of driving is generated.

What is important here is that the positional relationship of the charging sequence between the protective film material and the toner greatly affects the electrostatic transport characteristics. When the toner is negatively charged, the charging deterioration of the charged toner is reduced by using a silicone-based or polycarbonate-based resin as the organic material. In inorganic materials, charging deterioration occurs in SiO ₂ , but there is little charging deterioration in Ta ₂ O ₅ and Si ₃ N ₄ .

In addition, ZrO ₂ , BaTiO ₃ , Y ₂ O ₃ singly or a composite material thereof has a charge amount of 30% from a slight increase depending on the transport distance and drive frequency in the electrostatic transport process. To increase. Therefore, by using these materials for the surface protective film, compensation of the low-charged toner to the appropriately charged toner can be automatically performed during the conveyance. .

Next, another example of the skeleton electrode member 11 will be described with reference to FIG. FIG. 7 is an explanatory plan view of the main part of the skeleton electrode member.
In the skeleton electrode member 11, a bridging portion 21, which is a linear reinforcing means, is formed integrally with the electrode wires 12 between the electrode wires 12 and 12 along the conveying direction.

  That is, when the electrode wire 12 has a straight shape, the skeleton electrode member 11 having a snowboard shape or a slender shape has a lack of mechanical strength, is greatly deformed or stretched, and may be bent or curled. When this skeleton electrode member 11 is adjusted to a spatially laminated configuration, a tension is required in the lateral direction. At this time, if a tension exceeding the fracture yield point of the material is applied, the skeleton electrode member 11 is easily extended.

  Therefore, one or a plurality of bridging portions 21 between the electrode wires 12 and 12 are linearly provided and fixed between the electrode wires 12 and 12 adjacent to each other, or provided in a staggered manner and fixed to the linear drops ( In the example of FIG. 7, the mechanical strength can be reinforced by using a mesh structure in plan view.

  In this case, when the width of the electrode wire 12 is a, when the above-described n-phase (three-phase) voltage is applied to generate a phase-shift electric field, a three-layer space laminated structure is formed. Although the gap 13 between 12 is about 5 × a, the line width of the bridge portion 21 described above is about a, and the pitch of the bridge portion 21 is preferably 10a to 100a, particularly preferably 30 × a to 60 ×. a is that the rigidity of the metal material is maintained, there is no bending, and a contact short circuit between the upper and lower electrode wires 12 due to vibration during electrostatic transport driving can be prevented.

  The line width a of the electrode line 12 is preferably 30 μm to 500 μm, particularly preferably 80 μm to 200 μm, although it depends on the configuration and the driving voltage. By making this range, the skeleton electrode member 11 is formed. If the thickness T of the metal material to be used is 100 to 300 m, the rigidity of the metal material can be maintained, there is no bending, and no contact short circuit between the upper and lower electrode lines 12 due to vibration during electrostatic transport driving does not occur.

Next, another example of the bridging portion 21 between the electrode wires 12 will be described with reference to FIG. FIG. 8 is an explanatory plan view of the main part of the bridging portion of the skeleton electrode member.
That is, the planar shape of the bridging portion 21 is not limited to the linear shape described above, and may be a shape as shown in FIGS. In addition, (a) is an inclined line, (b) is an S-shaped curve, (c) is a forwardly arranged taper shape (taper direction is the same), (d) is an alternately arranged taper shape (taper direction is alternating) (E) an acute angle shape, and (f) is an example of a half moon shape.

  In other words, when the bridging portion 21 is provided, it is preferable that the upper and lower electrode wires 12 are superimposed as little as possible so as not to interfere with the force of the traveling wave electric field in the charged toner conveyance direction. Therefore, by providing an inclination, a curvature line, a taper, etc., the overlapping of the upper and lower electrode lines 12 can be reduced. Furthermore, by adopting these shapes, it is possible to give deflection to the electric field distribution and to give diffusion and concentration to the toner conveyance. As a result, for example, when used in a developing device, a toner distribution that becomes non-uniform by being partially consumed by development or the like can be corrected to a uniform distribution as much as possible by diffusion and concentration.

Next, another example of the skeleton transport member 1 will be described with reference to FIGS. 9 and 10. 9 is an explanatory side view of the skeleton transport member, and FIG. 10 is an explanatory plan view illustrating different arrangement examples of the gap maintaining members of the skeleton transport member.
In the skeleton transport member 1, an insulating gap maintaining member 22 as a gap maintaining means is interposed between the electrode wires 12 and 12 of the upper and lower skeleton electrode members 11 and 11. The gap maintaining member 22 is bonded and fixed to one or both of the upper and lower electrode wires 12 and 12 by thermocompression bonding, using a peripheral surface of an insulating material 22a coated with a thermoplastic resin 22b.

  As the insulating material 22a, for example, an organic insulating material having high heat resistance, such as polyimide, liquid crystal plastic, urea resin, fluororesin having a glass transition point of 100 ° C. or higher, or a material in which glass fiber is mixed therein, or the like is used. Can be used. The thickness of the thermoplastic resin 22b is 0.5 to 3 μm. The entire gap maintaining member 22 can also be formed of a thermoplastic resin material. The diameter of the insulating material 22a of the gap maintaining member 22 is, for example, 50 μm to 300 μm, although it depends on the distance between the upper and lower electrode wires 12.

  The gap maintaining member 22 can be arranged as shown in FIG. FIG. 10A is an example of a linear arrangement, FIG. 10B is an example of a random arrangement, FIG. 10C is an example of an oblique arrangement, and FIG. 10D is an example of an oblique arrangement. is there. In particular, it is preferable to dispose the toner so that the toner is directed inward at both ends in the direction intersecting the transport direction of the transport region.

  Note that the cross-sectional shape of the gap maintaining member 22 is not limited to the circular shape described above, but may be triangular as shown in FIG. 11, or may be elliptical as shown in FIG. It can also be made into a polygonal shape.

  Thus, by interposing the gap maintaining member 22 between the electrode wires 12 and 12 of the upper and lower skeleton electrode members 11 and 11, the mechanical strength between the upper and lower electrode wires 12 is reinforced, and the electrode wire 12 at the time of driving is also provided. It is possible to prevent contact short-circuit between the upper and lower electrode wires 12 due to the vibration of.

Next, still another example of the skeleton transport member 1 will be described with reference to FIG. FIG. 13 is an explanatory side view of the skeleton transport member.
The skeleton transport member 1 is configured by fixing both end portions in a direction intersecting the transport direction of the skeleton electrode member 11 with end fixing members 24 made of an insulating material.

  That is, when a space laminated structure of the electrode wires 12 is manufactured, the space between the electrode wires 12 is protected by the gap maintaining member 22 in the vertical direction, but for fixing both ends and the shape of the skeleton electrode member 11 In addition, end fixing members 24 made of a highly insulating material are provided at both ends of the skeleton electrode member 11 so as to secure a gap, insulate, and fix the shape. In this case, it is preferable to fix at both ends of the skeleton electrode member 11 in order to secure an area necessary for toner conveyance.

Next, still another example of the skeleton transport member 1 will be described with reference to FIG. FIG. 14 is an explanatory side view of the skeleton transport member.
As described above, the skeleton transporting member 1 is positioned 1 / n at a time by setting the phase of the voltage for applying the electrode wire 12 to the three skeleton electrode substrates 11 in the toner transport direction as n phases (three phases in this example). In addition to being spatially stacked and shifted, the positions are also shifted in the direction intersecting the transport direction.

  That is, when the skeleton electrode substrate 11 is reinforced by providing the bridging portion 21 as described above, if the bridging portion 21 is in the same position in the upper and lower sides, there is a possibility that the traveling wave electric field may be distorted. By disposing the substrate 11 in a direction crossing the transport direction, the overlapping of the bridging portions 21 that bridge the electrode wires 12 is reduced, and the distortion of the traveling wave electric field is reduced. Thus, stable toner conveyance can be performed.

Next, a second example of the skeleton transport member will be described with reference to FIGS. 15 and 16. 15 is an explanatory plan view of the skeleton conveying member, and FIG. 16 is an explanatory side view of the skeleton conveying member.
The skeleton transport member 51 has a plurality of electrode wires 52 arranged in a spatial manner with a gap 53 interposed therebetween, and both ends of each electrode wire 52 are fixed and held by an insulating electrode wire fixing member 55. In this example, three bus lines (an example in which the applied voltage is three-phase) 56 provided on the wire fixing member 55 and the electrode wire 52 are electrically connected.

  Specifically, as shown in FIG. 17, for example, a member 61 in which an electrode wire 52 is formed with a 100 μm line width and a gap 53 is formed with a 100 μm width on a conductive member such as SUS304 and both ends are cross-linked with a bridging portion 62 is manufactured. As shown in FIG. 18A, after fixing the electrode wire fixing member 55 to both ends of the member 61, the bridging portion 62 of the member 61 is cut as shown in FIG. A member in which a plurality of electrode wires 52 whose both ends are fixedly held by the electrode wire fixing member 55 is arranged through the gap 53 is formed. Then, as shown in FIGS. 18C and 24, the three bus lines (common electrode lines) 56 formed on the electrode wire fixing member 55 and the electrode wires 52 are sequentially electrically connected by wire bonding 57 or the like. To do.

  Note that the common electrode line and the individual electrode lines 52 can be formed using an FPC, an AFC connector, or the like as shown in FIGS. That is, three common electrode lines 66 of the FPC 65 are formed, and the contact hole 67 is formed by covering the other lines 66 with the insulating layer 68 and connected to the electrode line 52 via the anisotropic junction AFC 69. .

  In this way, in the skeleton transport member 51 in which a plurality of electrode lines 52 to which voltages of different phases are applied in a line are arranged in a spatial manner through the gap 53, for example, a drum-shaped image that forms a latent image The shape of the skeleton transport member can be arranged along the peripheral surface of the carrier, and the development area can be easily widened.

  Since the space (gap 53) is formed between the electrode wires 52, a low-charged toner or an uncharged toner falls from the gap and selectively conveys only normal charged toner, for example. It can be used for development. Further, similarly to the skeleton conveying member 1, it is possible to prevent toner from adhering to and sticking to the electrode wires.

Next, the principle of toner conveyance by the skeleton conveyance member 1 will be described.
By applying an n-phase pulse voltage to the plurality of electrode wires 12 of the skeleton transport member 1, a phase shift electric field (traveling wave electric field) is generated by the plurality of electrode wires 12, and charging on the skeleton transport member 1 is performed. The toner that has been subjected to repulsive force and / or suction force moves in the transport direction.

  For example, as shown in FIG. 22 with respect to the plurality of electrode wires 12 of the skeleton transport member 1, three phases of A phase, B phase, and C phase that change between the ground G (0 V) and the positive voltage + are shown. A pulse-like driving waveform (voltage) is applied at different timings.

  At this time, as shown in FIG. 23, the negatively charged toner T is present on the skeleton transport member 1, and a plurality of spatially continuous electrode wires 12 (here, between the three layers of skeleton electrode members 11). Assuming that “G”, “G”, “+”, “G”, and “G” are respectively applied to the continuous electrode lines 12) ((a) in the figure), the negatively charged toner T is “+”. Located on electrode 102. At the next timing, “+”, “G”, “G”, “+”, and “G” are respectively applied to the plurality of electrodes 102 ((b) in the figure). Since the repulsive force acts between the electrode line 12 of “G” and the attraction force acts between the electrode line 12 on the right side and the “+” electrode line 12, the negatively charged toner T moves to the “+” electrode line 12 side. To do. Further, as shown in FIG. 5C, “G”, “+”, “G”, “G”, and “+” are applied to the plurality of electrode lines 12 at the next timing, respectively, so that they are negatively charged. Similarly, since the repulsive force and the attractive force act on the toner T, the negatively charged toner T further moves to the “+” electrode line 12 side.

Therefore, a first embodiment of the developing device according to the present invention using the skeleton conveying member 1 described above will be described with reference to FIG. FIG. 24 is a schematic explanatory diagram of the embodiment.
The developing device has a configuration similar to that of the skeleton conveying member 1 that conveys toner for development to the area facing the image carrier 101 where a latent image is formed in the case 100 (conveys in the forward direction). In order to return the toner that did not contribute to the development, such as the toner skeleton transporting member 111 and the toner that has been placed on the lower side of the developing skeleton transporting member 111 and the electric field rebounded due to the ground potential of the image carrier 101. A return skeleton conveying member 112 having the same configuration as the skeleton conveying member 1 to be conveyed is provided.

  Here, the developing skeleton conveying member 111 has a leading end facing the image carrier 101 formed of a belt-like (drum-shaped) photosensitive member on which a latent image is formed, and the leading end of the skeleton conveying member 111. By ejecting the toner from the part, the toner is attached to the latent image on the image carrier 101 and developed. Further, on the rear end side (toner supply side) of the skeleton conveying member 111, a developer carrier 103 that supplies charged toner, for example, holds the charged toner with a magnetic brush, is disposed. In order to receive the supply of charged toner, the skeleton transport member 111 is provided with an inclined portion 111A.

  The return skeleton conveying member 112 is arranged such that the rear end (toner inlet portion) faces the image carrier 101 and the front end (toner outlet portion) faces the toner supply portion side of the developing skeleton conveying member 111. is doing. The leading end and the trailing end are defined as a trailing end on the upstream side in the toner transport direction and a leading end on the downstream side in the transport direction.

  In this developing apparatus, the amount of toner is 0.5 in the traveling direction of the phase-shifting electric field without adhering to the upper surface of the developing skeleton conveying member 111, the space 14 (hollow inside) between the skeleton electrode members 11 of each layer, and the lower surface. Move at a high speed of ~ 2m / sec. At this time, the high-speed charged toner transported by the skeleton transport member 111 that is ideally configured in a straight line is bundled and flies at a high speed from the tip of the skeleton transport member 111 to a maximum of 500 μm. Fly to 1-5mm ahead due to the inertia of the toner.

  Therefore, by arranging the image carrier 101 at a position of 0.2 to 0.5 mm from the front end portion of the skeleton transport member 111, the toner ejected from the front end portion of the skeleton transport member 111 is a latent image of the image carrier 101. It is possible to develop the latent image in a non-contact manner without attaching to the non-image portion (background portion).

  At this time, the skeleton conveying member 111 does not cause toner adhesion and fixation as described above, and can convey a large amount of toner, so that stable development can be performed at high speed.

  The charged toner that is repelled by the background potential of the image carrier 101 and does not contribute to development among the charged toner ejected from the tip of the developing skeleton conveying member 111 is applied to the drive electric field of the returning skeleton conveying member 112. The toner is taken in and transported in the reverse direction, and from the return skeleton transport member 112 to the development skeleton transport member 111 again from the reverse feed end portion (exit portion), is circulated (recycled), and is efficiently recycled. Can be used.

  In this developing device, a bias electrode member 113 to which a bias voltage having the same polarity as the charging polarity of the toner is applied is disposed on the upper side so as to face the developing skeleton conveying member 111, and opposed to the returning skeleton conveying member 112. A bias electrode member 114 to which a bias voltage having the same polarity as the charging polarity of the toner is applied is disposed on the lower side. These bias electrode members 113 and 114 have inclined portions 113a and 114a on the image carrier 101 side so that the openings are narrowed across the tip of the developing skeleton transport member 111.

  As the bias electrode members 113 and 114, for example, a metal plate or an organic member formed with a conductive material film can be used. In addition, the gap between the bias electrode member 113 and the development skeleton transport member 111 and the gap between the bias electrode member 114 and the return skeleton transport member 112 are preferably in the range of 0.5 mm to 10 mm, for example.

  Thus, when the toner is transported, when the toner collides with the end face of the electrode wire 12 of the skeleton electrode member 11, the flight direction is bent and the electric field region formed by the skeleton transport members 111 and 112 is changed. There is a risk of jumping out and scattering. The toner hopping is concentrated at a height of 200 to 500 μm from the surface of the skeleton electrode member 11. The upper and lower sides of the skeleton transport members 111 and 112 are not controlled in the cloud state as toner scattering when the toner due to this hopping jumps out of the transport electric field, causes environmental pollution, and cannot control the transport toner amount. .

  Therefore, by arranging bias electrode members 113 and 114 to which a bias voltage having the same polarity as the toner charging polarity is applied above and below the upper and lower skeleton transport members 111 and 112, the spatial electric field control is performed up to the range of the transport electric field. It is possible to repel the toner that is about to jump out of the electric field region formed by the skeleton transport members 111 and 112 and return it to the skeleton transport member 111 side, thereby preventing charging toner from being trapped and scattered by hopping. It is possible to improve the efficiency of the toner conveyance amount.

  Further, in this developing device, an opening (notched, including a case where the bias electrode member 114 is in a state of being retracted from the end surface of the skeleton transport member 111 in an initial state) on the developer carrier 103 side of the lower bias electrode member 114 is included. Is provided. An opening can also be provided on the image carrier 101 side (the inlet side near the toner recycling). Note that a structure having a small-diameter hole or a mesh-like member can be used as long as the bias electric field does not impair the function.

  That is, when the charged toner is electrostatically transported, depending on the skeleton electrode member 11 and the insulating material on the surface thereof, and its driving frequency and distance, the toner itself rolls when it is grounded and hits several hundred to several thousand times. And charging deterioration occurs. In addition, it affects the environmental humidity, and charging deterioration of 20 to 30% occurs at RH 80%. However, as will be described later, depending on the surface material, it is possible to eliminate the charging deterioration and to achieve a slight improvement.

  This charged and deteriorated toner needs to be separated for recharging. Therefore, the weakly charged or charged deteriorated toner has a weak electric field constraint and falls without being controlled by the drive electric field or the bias electrode electric field, and is dropped from the opening 115 of the bias electrode member 112 or the hole of the mesh member. The toner that is sent again to the toner charging means such as the developer carrier 102 through the collecting means 119 and maintains the proper charge can be returned to the skeleton conveying member 111 and recycled.

  Further, in this developing device, a recoil bias electrode member 117 to which a bias voltage having the same polarity as the charged toner is applied is provided at the entrance portion (image carrier 101 side) of the return skeleton conveying member 112. As the recoil bias electrode member 117, for example, an electrode wire, a belt-like member, or a rod-like member can be used.

  That is, the image carrier 101 is developed by applying a bias voltage having the same polarity as that of the charged toner (a voltage larger than that of the upper and lower bias electrode members 113 and 114 as necessary) to the recoil bias electrode member 117. The toner can be efficiently collected by repelling the scattered toner taken in by the air velocity due to the linear velocity and feeding it to the drive electric field of the return skeleton conveying member 112.

  Similarly, a recoil bias electrode member 118 to which a bias voltage having the same polarity as that of the charged toner is applied is provided at the exit portion of the return skeleton conveying member 112. As the recoil bias electrode member 118, for example, an electrode wire, a strip-like member, or a rod-like member can be used.

  That is, in the return transport of the toner by the return skeleton transport member 112, a toner having a long electrostatic transport distance and a toner whose charging deterioration is large and a toner in which proper charge is maintained are generated. Only the charged toner that can withstand the development is recoiled by the recoil bias electrode member 118 to which the same polarity potential bias is applied at the reverse feed end portion of the return skeleton transport member 112 to the development skeleton transport member 111. I am trying to make it take in. Thereby, the charge amount of the toner to be recycled can be made uniform.

Next, voltage applying means for applying a driving voltage to the electrode wire 12 of the return skeleton conveying member 112 of the developing device will be described with reference to FIG.
The voltage application means generates and outputs a pulse signal from a pulse signal generation circuit 201, and generates and outputs pulse voltages V11, V12, and V13 as drive waveforms by inputting the pulse signal from the pulse signal generation circuit 201. Amplifiers 202a, 202b, 202c.

  The pulse signal generation circuit 201 receives, for example, a logic level input pulse and drives switching means, eg, transistors, included in the waveform amplifiers 202a to 202c in the next stage with two sets of pulses that are phase-shifted by 120 ° to 200V. A pulse signal having an output voltage of 10 to 15 V at a level that can perform switching is generated and output. The waveform amplifiers 202a, 202b, and 202c apply three-phase drive waveforms (pulse voltage) V11, V12, and V13 to the electrode lines 12, respectively.

  Here, for each electrode line 12 of the skeleton transport member 112, for example, as shown in FIG. 26, the application time ta of −100 V of each phase is about 30% (exactly 1/3 of the repetition period tf). 3 phase pulse voltage V11, V12, V13 set to 33%).

  Here, with respect to each electrode line 12 of each skeleton electrode member 11 in the development region of the skeleton conveying member 112, the phase of a pulse voltage having the same voltage value, duty, and frequency is shifted as shown in FIG. However, since the electrode wires 12 of the skeleton electrode members 11 of each layer are spatially stacked, the toner conveyed by the electrode wires 12 of the skeleton electrode member 11 of the lower layer is a gap. The charged toner can be greatly hopped (rebounded) by the electrode wire 12 that is transferred onto the electrode wire 12 of the upper skeleton electrode member 11 via the electrode 13 and is closest to the developing skeleton conveying member 111.

  In other words, a pulse voltage that causes the charged toner to repel and fly larger than the other electrode wire layers is applied to the electrode wire layer on the developing skeleton carrying member side of the return skeleton carrying member. Then, the charged toner is largely hopped on the return skeleton conveying member, and the charged toner is greatly ejected toward the developing skeleton conveying member that is conveyed in the forward feeding direction, and the toner is collected in the electric field on the developing skeleton conveying member side. As a result, it is possible to maintain the density of the charged toner and improve its utilization efficiency.

Therefore, such a pulse voltage will be described with reference to FIGS.
First, in the pulse voltage shown in FIG. 27, the pulse voltage V21 applied to the electrode line 12 of the uppermost skeleton electrode member 11 is set to −150 V, and the electrode lines 12 of the lower two skeleton electrode members 11 and 11 are applied. By setting the applied pulsed voltages V21 and V23 to −100V, toner hopping by the uppermost skeleton electrode member 11 is maximized.

  The pulse voltage shown in FIG. 28 has a pulse duty of the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 of 40 to 60%, and the skeleton electrode members 11 and 11 of the lower two layers. By setting the pulse duty of the pulse voltages V21 and V23 applied to the electrode wire 12 to 33%, the time for the uppermost skeleton electrode member 11 to repel toner (toner flight time) becomes longer.

  Further, in the same manner as in FIG. 27, the pulse voltage shown in FIG. 19 is such that the pulse voltage V21 applied to the electrode line 12 of the uppermost skeleton electrode member 11 is −150 V, and the skeleton electrode members 11 The pulse voltages V21 and V23 applied to the eleventh electrode wire 12 are set to -100V, the pulse duty of the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 is set to 40 to 60%, By setting the pulse duty of the pulse voltages V21 and V23 applied to the electrode wires 12 of the skeleton electrode members 11 and 11 of the two layers to 33%, the time for repelling the toner by the skeleton electrode member 11 of the uppermost layer (toner The flight time) can be lengthened, and the toner can be hopped high.

  Next, the developer carrier 103 will be described. As described above, when developing is performed while the charged toner is conveyed by circulation recycling using the skeleton conveying members 111 and 112, the hopping at the time of electrostatic conveyance can be made uniform by agitation by the hopping at the time of conveyance. In terms of scale, toner density unevenness may occur. Further, the toner density is low in a portion where the charged toner is subjected to development with respect to the image carrier 101, but remains high in a portion where the toner is not subjected to development. For this reason, ghosting may occur in the subsequent development due to the uneven density of the charged toner.

  Here, the amount of toner when pumping from the developer carrier 103 to the skeleton conveying member 111 can be adjusted by a bias potential applied to the developer carrier 103. Therefore, even if the bias potential for feeding charged toner from the developer carrier 103 is constant, the toner density is distributed by repeated development, so the bias electrode of the developer carrier 103 is divided. The toner density is corrected by detecting the toner density in each region corresponding to the divided bias electrode with a sensor and adjusting the bias potential applied to the divided bias electrode based on the detection result. To do. Actually, the toner density on the skeleton conveying member 111 is adjusted by adjusting the bias potential by dividing into 3 or 4 for the A4 size width 210 mm and 4 to 6 for the A3 size width 290 mm. Unevenness was eliminated.

Next, a first embodiment of an image forming apparatus according to the present invention that forms an image with color superposition provided with a process cartridge according to the present invention will be described with reference to FIG.
This image forming apparatus forms an image bearing member 301 made of a belt-like photosensitive member and a yellow image arranged from the upstream side to the downstream side in the circumferential direction (arrow direction) of the image bearing member 301. A process cartridge 304Y including the developing device according to the present invention, in which the image carrier 301 is uniformly charged and yellow toner is attached to the latent image formed by the writing device 303 on the image carrier 301 for development. In the same manner, a process cartridge 304M for forming a magenta image, a process cartridge 304C for forming a cyan image, a process cartridge 304K for forming a black image, and a toner image of each color are superimposed on the image carrier 1. A transfer device 305 for transferring the full-color toner image formed in this way, a fixing device 306, and a transfer material 307; And a and paper feeding device 308 to volume.

  Here, the image carrier 301 includes a conveying roller 311, a driven roller 312, a transfer counter roller 305B constituting the transfer device 305, and counter rollers 313Y, 313M, 313C, and 313Y that face the process cartridges 304Y, 304M, 304C, and 304K. It is bridged between them and moves around in the direction of the arrow by the rotation of the transport roller 311.

  The writing device 303 writes a latent image on the image carrier 301 charged according to the image information, and various devices such as an optical scanning device using a laser and an LED array can be used.

  As shown in FIG. 31, the process cartridge 304 integrates a corotron charger 321 that is a non-contact type charging device that uniformly charges the image carrier 301 and a developing device 322 according to the present invention to form an image. The apparatus main body 310 is configured to be detachable. As in the above-described embodiment, the developing device 322 includes a developing skeleton conveying member 111 that ejects toner from the front end portion to the image carrier 301 and a return skeleton conveying member 112 that returns the toner into the case 100. And the like, and a developer carrier 103 using a magnetic brush for supplying charged toner to the skeleton conveying member 111, and a container 104 for agitating the toner pumped up by the developer carrier 103, and agitating the toner and the carrier A paddle 105 is arranged. Further, a layer thickness regulating member 106 that regulates the layer thickness of the developer on the developer carrier 103 is provided.

  The transfer device 305 includes a transfer roller 305A and a transfer counter roller 305B. The fixing device 306 includes a heating roller 306A and a pressure roller 306B facing the heating roller 306A.

  In this image forming apparatus, when functioning as a copying machine, image information read from a scanner (not shown) is subjected to various image processing such as A / D conversion, MTF correction, gradation processing and the like to write data. Converted. Also, when functioning as a printer, image processing is performed on image information in a format such as a page description language or a bitmap transferred from a computer or the like, and converted into write data.

  Prior to image formation, the image carrier 301 starts circular movement in the direction of the arrow so that the moving speed of the surface becomes a predetermined speed. At this time, the image carrier 301 is uniformly charged by the charging device 321 of the process cartridge 304Y at a predetermined timing, and the writing device 303 first responds to the yellow image write data with respect to the charged image carrier 301. Then, the laser beam 303a is irradiated for exposure. That is, by changing the potential of the image portion by light irradiation, a difference from the potential of the non-image portion not irradiated with light is generated, and an electrostatic latent image is formed by this potential contrast. Then, yellow toner is attached to the image portion of the electrostatic latent image formed on the image carrier 301 by the developing device 322, and a yellow toner image is formed on the image carrier 301.

  Next, the image carrier 301 including the yellow image is uniformly charged by the charging device 321 of the process cartridge 304M including the region where the yellow toner image is formed. The writing device 303 performs exposure by irradiating a laser beam 303a according to the writing data of the magenta image, and forms an electrostatic latent image of the magenta image. Then, a magenta toner is attached to the image portion of the electrostatic latent image formed on the image carrier 301 by the developing device 322, and a toner image in which the magenta toner image is superimposed on the yellow toner image is an image carrier. 301 is formed.

  Similarly, charging, exposure (writing), and development are performed, and a toner image in which a cyan toner image is superimposed on a yellow and magenta toner image is formed on the image carrier 301. A toner image in which a black toner image is superimposed on the superimposed toner image is formed on the image carrier 301.

  On the other hand, the transfer material 307 is fed from the paper feeding device 308 at a predetermined timing, and the color superimposed toner image on the image carrier 301 is transferred to the transfer material 307 by the transfer device 305 and fixed by the fixing device 306. Thereafter, the transfer material 307 on which the full-color image is formed is discharged to the paper discharge unit 509.

  In this image forming apparatus, the process cartridge 304 for forming yellow, magenta, cyan, and black toner images is detachable from the image forming apparatus main body 310. That is, as shown in FIG. 32, the process cartridge 304 is detachable from the open space when the image carrier 301 is opened and retracted from the apparatus main body 310, and can be replaced by the user. .

Therefore, a second embodiment of the developing device according to the present invention using the skeleton conveying member 1 described above will be described with reference to FIG. FIG. 33 is a schematic explanatory view of the embodiment.
The developing device has a configuration similar to that of the skeleton transport member 1 that transports toner for development to the area facing the image carrier 401 on which a latent image is formed (conveys in the forward direction) in the case 400. In order to return the toner that has not contributed to the development, such as the toner skeleton conveying member 411 and the toner that has been placed on the lower side of the developing skeleton conveying member 411 and has rebounded from the electric field due to the ground potential of the image carrier 401. A return skeleton transport member 412 having the same configuration as the skeleton transport member 1 to be transported is provided.

  In this developing device, a developing nip portion is formed by arranging the peripheral surface of the image carrier 401 on which a latent image is formed to face the conveying surface of the developing skeleton conveying member 411, and the skeleton conveying member 411 forms a toner. Then, the toner is attached to the latent image on the image carrier 401 and developed. Further, a developer carrier 403 that supplies charged toner, for example, holds the charged toner with a magnetic brush, is disposed on the rear end side (toner supply side) of the skeleton conveying member 411.

  The return skeleton conveying member 412 has an inclined portion 412A such that the rear end (toner inlet portion) faces the image carrier 401 and the front end (toner outlet portion) approaches the developing skeleton conveying member 411. Is formed. The leading end and the trailing end are defined as a trailing end on the upstream side in the toner transport direction and a leading end on the downstream side in the transport direction.

  As described above, the inclined portion 412A is formed at the reverse feed end portion of the return skeleton conveyance member 412, and physically close to the development skeleton conveyance member 411, whereby the charged toner flying conveyed by the return skeleton conveyance member 412 is obtained. The charged toner can be ejected and taken into the developing skeleton conveying member 411 using inertia at a speed of 0.5 to 1.5 m / s.

  As a result, the charge-deteriorated or weakly-charged toner has a toner flying speed of 0.3 m / s or less, does not reach the vicinity of the developing skeleton conveying member 411, falls down, and again enters the toner charging means into the system. It can be returned and recharged.

  In this developing device, the toner is 0.5 in the traveling direction of the phase-shifting electric field without adhering to the upper surface of the developing skeleton conveying member 411, the space 14 (hollow inside) between the skeleton electrode members 11 of each layer, and the lower surface. It moves while being transported and hopped at a high speed of ~ 2m / sec. At this time, as described above, the skeleton conveying member 411 does not cause adhesion and fixation of toner, and can convey a large amount of toner, so that stable development can be performed at high speed.

  Then, the charged toner that is repelled by the background potential of the image carrier 401 and does not contribute to development among the charged toner that is transported and hopped by the developing skeleton transporting member 111 returns from the end of the developing skeleton transporting member 111. Is taken in by the drive electric field of the skeleton conveyance member 412 and conveyed in the reverse direction, and is again taken in the drive electric field from the reverse feed end (exit part) of the return skeleton conveyance member 412 to the development skeleton conveyance member 411 and circulated. (Recycled) and the toner can be used efficiently.

  In this developing device, a bias electrode member 413 to which a bias voltage having the same polarity as the charging polarity of the toner is applied is disposed on the upper side facing the developing skeleton conveying member 411. As the bias electrode member 413, for example, a metal plate or a member in which a conductive material film is formed on the surface of an organic member can be used. Further, the gap between the bias electrode member 413 and the development skeleton transport member 411 is preferably set within a range of 0.5 mm to 10 mm, for example.

  In this way, when toner is transported, when the toner collides with the end face of the electrode wire 12 of the skeleton electrode member 11, the flight direction is bent and the toner jumps out of the electric field region formed by the skeleton transport member 411. There is a risk of scattering. The toner hopping is concentrated at a height of 200 to 500 μm from the surface of the skeleton electrode member 11. When the toner hopped in the upward direction of the skeleton transport member 411 jumps out of the transport electric field, the toner is scattered and the cloud state is not controlled, and environmental pollution occurs or the transport toner amount cannot be controlled.

  Therefore, by disposing a bias electrode member 413 to which a bias voltage having the same polarity as the charging polarity of the toner is applied above the skeleton transport member 411, the spatial electric field can be controlled to the range of the transport electric field, and the skeleton transport is performed. The toner that tries to jump out of the electric field formed by the member 411 can be repelled and returned to the skeleton conveying member 411 side, and the toner can be prevented from being encapsulated and scattered by hopping. Can be improved.

  Further, bias electrode members 417 to which a bias voltage having the same polarity as that of the charged toner is applied are arranged on the front side of the front end of the developing skeleton conveying member 411 and on the rear side of the rear end of the returning skeleton conveying member 412. As the bias electrode member 417, for example, an electrode wire, a belt-like member, or a rod-like member can be used. As a result, the charged toner conveyed to the tip of the developing skeleton conveying member 411 without being subjected to development can be repelled and reliably taken into the conveying electric field of the returning skeleton conveying member 411.

  Similarly, a recoil bias electrode member 418 to which a bias voltage having the same polarity as that of the charged toner is applied is provided corresponding to the inclined portion 412A of the return skeleton conveying member 412. As the recoil bias electrode member 418, for example, an electrode wire, a belt-like member, or a rod-like member can be used.

  That is, in the return transport of the toner by the return skeleton transport member 412, a toner having a long electrostatic transport distance and a toner whose charge deterioration is large and a toner in which proper charge is maintained are generated. Only the charged toner that can be separated, dropped, and withstands development is rebounded by the bias electrode member 418 to which the same polarity potential bias is applied at the reverse feed end portion of the return skeleton transport member 412 to the development skeleton transport member 411. I am trying to make it take in. Thereby, the charge amount of the toner to be recycled can be made uniform.

  In this developing device, as described above, the toner is transported in the traveling direction of the phase-shifting electric field without adhering to the upper surface of the skeleton transport member 411, the space 14 (hollow interior) between the skeleton electrode members 11 of each layer, and the lower surface. Since a large amount of toner can be conveyed, stable development can be performed at high speed.

  Next, voltage applying means for applying a voltage to the electrode wire 12 of the skeleton transport member 411 of the developing device will be described with reference to FIG. Here, the electrode line 12 of the skeleton conveying member 1 is opposite to the electrode line 12 in the conveying area for conveying the toner to the image carrier 401 to face the latent image on the image carrier 401. It is assumed that a pulse voltage is applied separately to the electrode wire 12 in the (development region). In addition, the same code | symbol is attached | subjected to the part corresponding to embodiment mentioned above.

  The voltage application means generates and outputs a pulse signal from a pulse signal generation circuit 201, and generates and outputs pulse voltages V11, V12, and V13 as drive waveforms by inputting the pulse signal from the pulse signal generation circuit 201. Amplifiers 202a, 202b, and 202c, and waveform amplifiers 203a, 203b, and 203c that generate and output pulse voltages V21, V22, and V23, which are drive waveforms, by inputting a pulse signal from the pulse signal generation circuit 201, are provided.

  The pulse signal generation circuit 201 receives, for example, logic level input pulses, and includes two sets of pulses that are phase-shifted by 120 °, and includes switching means such as transistors included in the waveform amplifiers 202a to 202c and 203a to 203c in the next stage. It generates and outputs a pulse signal having an output voltage of 10 to 15 V that can be driven to perform switching of 200 V.

  The waveform amplifiers 202a, 202b, and 202c apply three-phase driving waveforms (pulse-like voltages) V11, V12, and V13 to the electrode lines 12 in the transport region, and the waveform amplifiers 203a, 203b, and 203c Three-phase drive waveforms (pulse voltage) V21, V22, and V23 are applied to each of the electrodes 12.

  Here, for each electrode line 12 in the transport region of the skeleton transport member 411, as shown in FIG. 26, the application time ta of −100 V for each phase is about 30 which is 1/3 of the repetition period tf. Three-phase pulse voltages V11, V12, V13 set to% (33% to be precise) are applied.

  Further, as shown in FIG. 35, for each electrode line 12 in the development region of the skeleton transport member 1, the application time ta of −100 V for each phase is set to about 67% which is 2/3 of the repetition period tf. The three-phase pulse voltages V21, V22, and V23 thus applied are applied.

  Here, with respect to each electrode line 12 of each skeleton electrode member 11 in the development region of the skeleton transport member 411, the phase of a pulse voltage having the same voltage value, duty, and frequency is shifted as shown in FIG. However, since the skeleton transporting member 1 has the electrode wires 12 of the skeleton electrode members 11 in each layer spatially laminated, the toner transported by the electrode wires 12 of the skeleton electrode member 11 in the lower layer is used. It can also be transferred onto the electrode line 12 of the upper skeleton electrode member 11 through the gap 13, and in this way, the toner is applied to the uppermost skeleton electrode member 11 (closest to the image carrier) in the development region. You can collect them for efficient development.

  In this case, the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 is, for example, -100V, and the pulse applied to the electrode wire 12 of the skeleton electrode members 11 and 11 of the lower two layers. By setting the state voltages V21 and V23 to −200V, the electric field strength of the lower layer is increased, and the toner is transferred to the uppermost skeleton electrode member 11 and concentrated.

  Similarly, the pulse duty of the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 is set to 30%, and the pulse voltage applied to the electrode wire 12 of the skeleton electrode members 11 and 11 of the lower two layers. By setting the pulse duty of V21 and V23 to 50%, it takes a long time for the lower layer to repel the toner, and the toner is transferred to the uppermost skeleton electrode member 11 and concentrated.

  Further, the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 is set to -200V, and the pulse voltage V21, V23 applied to the electrode wire 12 of the skeleton electrode members 11 and 11 of the lower two layers is set. −300 V, and the frequency of the pulse voltage V21 applied to the electrode wire 12 of the uppermost skeleton electrode member 11 is set to the pulse voltage V21 applied to the electrode wire 12 of the lower two skeleton electrode members 11, 11. By setting the frequency higher than the frequency of V23 (here, examples of 6 kHz and 3 kHz), the concentration of toner on the uppermost skeleton electrode member 11 and the hopping height can be increased.

Next, a second embodiment of the image forming apparatus according to the present invention including another process cartridge according to the present invention will be described with reference to FIG.
The image forming apparatus includes an image carrier, a charging unit, a developing unit according to the present invention as a developing unit, and an image forming unit including a cleaning unit, black (K), magenta (M), cyan (C), and yellow. (Y) process cartridges 501K, 501M, 501C, and 501Y (hereinafter simply referred to as “process cartridge 501” when not distinguished from each other; the same applies to others), optical writing devices 502K, 502M, Transfer rollers 503Bk, 503Bm, 503Bc, and 503By facing the transfer belt 503A and the process cartridges 501K, 501M, 501C, and 501Y with the transfer belt 503A interposed therebetween, the fixing device 504, the transfer belt 503A A sheet feeding device 505 that accommodates the material 506. .

  Here, the optical writing devices 502K, 502M, 502C, and 502Y are for writing a latent image on the charged image carrier of the process cartridges 501K, 501M, 501C, and 501Y according to image information, and optical scanning using polygons. Various devices such as devices and LED arrays can be used.

  The conveyance belt 503A is stretched between the conveyance roller 511, the driven roller 512, and the tension rollers 513 and 514, and rotates in the direction indicated by the arrow by the rotation of the conveyance roller 511. Then, an adsorption roller 515 for adsorbing the transfer material 506 onto the conveyance belt 503A is arranged facing the conveyance roller 511, and a toner image is formed on the conveyance belt 503A at the exit side of the conveyance belt 503A. A P sensor 516 for detecting a pattern is arranged.

The transfer rollers 503Bk, 503Bm, 503Bc, and 503By have at least a core metal and a conductive elastic layer covering the core metal, and the conductive elastic layer is an elastic material such as polyurethane rubber or ethylene-propylene-diene polyethylene (EPDM). In addition, an elastic roller in which a conductivity imparting agent such as carbon black, zinc oxide or tin oxide is blended and dispersed to adjust the electric resistance value (volume resistivity) to a medium resistance of 10 ⁶ to 10 ¹⁰ Ω · cm.

  The fixing device 504 includes a heating roller 504a and a pressure roller 504b facing the heating roller 504a.

  In this image forming apparatus, in a normal image forming operation, the transfer material 506 such as a recording sheet supplied from the paper supply device 505 is a transfer material that is a transfer body when a predetermined voltage is applied to the suction roller 515. It is adsorbed to the conveyance belt 503A. The transfer material 506 moves together with the transfer material conveyance belt 503A while being carried on the transfer material conveyance belt 503A. During the movement, the toner images of the respective colors are sequentially transferred from the process cartridges 501K, 501M, 501C, and 501Y. A color toner image is formed thereon. When the transfer material 506 passes through the conveyance belt 503A and reaches the fixing device 504, the toner image on the transfer material 506 is heated while being sandwiched between the heating roller 504a and the pressure roller 504b to be fixed on the transfer material 506. As a result, a visible image is fixedly formed on the transfer material 506. Thereafter, the transfer material 506 on which the color image is formed is discharged to a paper discharge unit 507 at the top of the apparatus main body 510.

  In the mode in which the color misregistration and toner density of each color toner image are adjusted, a toner image having a predetermined pattern is directly formed on the transfer material conveying belt 503A from the image forming units 501K, 501M, 501C, and 501Y. The toner pattern is detected, and the write timing and development bias are changed based on the detection result, so that an optimum color image can be obtained. The toner pattern on the transfer material conveyance belt 503A is adjusted in the charging polarity by the bias applied to the suction roller 515, and then the process cartridges 501K, 501M, 501C, Collected at 501Y.

Next, the process cartridge 501 according to the present invention will be described with reference to FIG. FIG. 37 is an enlarged explanatory view of the process cartridge.
The process cartridge 501 includes an image carrier 521, a contact charging member 531, the developing device 541 according to the second embodiment described above, and a cleaning device 551.

  The image carrier 521 is a negatively charged organic photoreceptor, and is provided so as to be rotated in the arrow direction (counterclockwise direction in the drawing) by a rotation driving mechanism (not shown). The contact charging member 531 is a flexible charging roller in which a foamed urethane layer of medium resistance in which a urethane resin, carbon black as conductive particles, a sulfurizing agent, a foaming agent, etc. are formulated in a roller shape is formed on a core metal. is there. The middle resistance layer formed on the core of the contact charging member (charging roller) 531 is not limited to the above urethane foam layer, but is urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber. A rubber material obtained by dispersing a conductive material such as carbon black or metal oxide in order to adjust resistance in (NBR), silicone rubber, isoprene rubber, or the like, or a foamed material thereof can be used.

  The cleaning device 551 includes a cleaning blade 552 that is brought into contact with the rotation direction of the image carrier 521 in the counter direction, a waste toner storage unit 553 that stores the cleaned toner particles as waste toner, and the like.

Next, the operation of the process cartridge 501 configured as described above will be described.
This image forming apparatus is a multifunction machine that can function as a copying machine and a printer. When the image forming apparatus functions as a copying machine, image information read from the scanner is subjected to various processes such as A / D conversion, MTF correction, and gradation processing. The image processing is performed and converted into write data. When functioning as a printer, image information is subjected to image processing on image information in a format such as a page description language or a bitmap transferred from a computer or the like, and converted into write data.

  Prior to image formation, the image carrier 521 starts rotating in the direction of the arrow, that is, in the counterclockwise direction so that the moving speed of the surface becomes a predetermined speed. The charging roller 531 is rotated with respect to the image carrier 521. At this time, a DC voltage of −100 V and an AC voltage of an amplitude of 1200 V and a frequency of 2 kHz are applied to the core of the charging roller 531 from the charging bias application power source, whereby the surface of the image carrier 521 is charged to about −100 V.

  The optical writing device 502 irradiates the charged image carrier 521 with a laser beam 502a in accordance with the writing data. That is, by changing the potential of the image portion by light irradiation, a difference from the potential of the non-image portion not irradiated with light is generated, and an electrostatic latent image is formed by this potential contrast.

  The electrostatic latent image formed on the image carrier 521 by the optical writing device 502 is developed by the developing device 541 according to the present invention, and is visualized on the image carrier 521 as a toner image by adhering toner particles to the image portion. Is done.

  The transfer material 506 is conveyed from the paper feeding device 505 in synchronization with the timing at which the toner image formed on the image carrier 521 arrives at the transfer portion that is the opposite portion between the transfer roller 503B and the image carrier 521. The toner image on the image carrier 521 is transferred to the transfer material 506 by the voltage applied to the transfer roller 503B. The transfer material 506 to which the toner image has been transferred is fixed by the fixing device 504, and a color image is output on the transfer material 506.

  On the other hand, toner remaining on the image carrier 521 without being transferred (transfer residual toner) is cleaned by a cleaning device 551, and the surface of the image carrier 521 after cleaning is used for the next image formation.

  The process cartridges 501K, 501M, 501C, and 501Y for forming these black, magenta, cyan, and yellow toner images are detachable from the image forming apparatus main body 510. That is, as shown in FIG. 38, the process cartridges 501K, 501M, 501C, and 501Y are detachable from the open space when the transfer material transport belt 503A is opened and retracted from the apparatus main body 510, and can be attached and removed by the user. Exchange is possible.

It is a plane explanatory view showing an example of a skeleton transport member used in the developing device according to the present invention. It is an expanded sectional explanatory view which follows the AA line of FIG. It is side surface explanatory drawing of the skeleton conveyance member. FIG. 6 is an explanatory diagram for explaining a toner transport operation by the skeleton transport member. It is an expanded section explanatory view showing an example of the section shape of the electrode line of the skeleton electrode member of the skeleton conveyance member. It is an expanded section explanatory view showing other examples of the section shape of the electrode line of the skeleton electrode member of the skeleton conveyance member. It is principal part plane explanatory drawing which shows the other example of the skeleton electrode member. It is principal part explanatory drawing which shows the example from which the planar shape of the bridge | crosslinking part of the skeleton electrode member differs. It is side surface explanatory drawing which shows the other example of the skeleton conveyance member. It is principal part plane explanatory drawing which shows the example from which a clearance gap maintenance member differs similarly. It is side surface explanatory drawing which shows the other example of the clearance gap maintenance member of the skeleton conveyance member. It is side surface explanatory drawing which shows the further another example of the clearance gap maintenance member. It is side surface explanatory drawing which shows another example of the skeleton conveyance member. It is side surface explanatory drawing which shows another example of the skeleton conveyance member. It is a plane explanatory view showing other examples of the skeleton conveyance member. It is a side explanatory view of the skeleton transport member, It is plane explanatory drawing of the electrode wire member with which it uses for description of the manufacturing process of the skeleton conveyance member. FIG. 23 is an explanatory plan view for explaining a process following FIG. 22 of the manufacturing process. It is principal part plane explanatory drawing used for description of the manufacturing process. It is principal part top explanatory drawing used for description of the modification of the skeleton conveyance member. It is front explanatory drawing of FIG. FIG. 6 is an explanatory diagram illustrating an example of a drive waveform applied to an electrode line for explaining a principle of conveyance by a skeleton conveyance member of a toner conveyance device. FIG. 6 is an explanatory diagram for explaining an example of toner conveyance. 1 is a schematic explanatory diagram illustrating a first embodiment of a developing device according to the present invention. It is a block diagram which shows an example of the voltage application means used for the developing device. It is explanatory drawing which shows an example of the voltage waveform applied to the return skeleton conveyance member of the developing device. It is explanatory drawing which shows the other example of the voltage waveform similarly applied to the return skeleton conveyance member. It is explanatory drawing which shows the further another example of the voltage waveform similarly applied to the return skeleton conveyance member. It is explanatory drawing which shows the further another example of the voltage waveform similarly applied to the return skeleton conveyance member. 1 is a schematic configuration diagram illustrating a first embodiment of an image forming apparatus according to the present invention including a process cartridge according to the present invention. It is a schematic block diagram of the process cartridge. FIG. 4 is an explanatory diagram for explaining attachment / detachment of the process cartridge to / from the image forming apparatus main body. It is a typical explanatory view showing a second embodiment of the developing device according to the present invention. It is a block diagram which shows an example of the voltage application means used for the developing device. It is explanatory drawing which shows an example of the voltage waveform applied to the image development area | region of the developing skeleton conveyance member of the developing device. 1 is a schematic configuration diagram illustrating a first embodiment of an image forming apparatus according to the present invention including a process cartridge according to the present invention. It is a schematic block diagram of the process cartridge. FIG. 4 is an explanatory diagram for explaining attachment / detachment of the process cartridge to / from the image forming apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Skeleton conveyance member 2 ... Voltage application means 11 ... Skeleton electrode member 12 ... Electrode wire 13 ... Space | gap 14 ... Space 21 ... Bridging part 22 ... Gap maintenance member 52 ... Electrode wire 53 ... Gap 55 ... Electrode wire fixing member 101 ... Image Support body 103... Developer support body 104. Toner container 111. Developing skeleton transport member 112. Return skeleton transport member 113 and 114... Bias electrode member 117 and 118... Bias electrode member 304 and 501.

Claims (14)

  In a developing device for developing a latent image on an image carrier by conveying toner by a conveying electric field formed by applying a multiphase voltage to a plurality of electrodes arranged at predetermined intervals, At least two skeleton conveying members having electrode lines constituting a skeleton structure and spatially stacked are provided, one being a developing skeleton conveying member for conveying the toner in the forward direction for development, and the other being A developing device, wherein the developing device is a returning skeleton conveying member that conveys toner that has not contributed to development in the reverse direction.   The developing device according to claim 1, further comprising a bias electrode member to which a bias voltage is applied so as to face the skeleton conveying member and suppress toner scattering.   The developing device according to claim 2, wherein an opening is formed in the bias electrode member facing the return skeleton conveying member.   4. The developing device according to claim 1, further comprising a bias electrode member to which a bias voltage having the same polarity as that of the charged toner is applied on a toner inlet portion side of the return skeleton conveying member. A developing device.   5. The developing device according to claim 1, further comprising a bias electrode member to which a bias voltage having the same polarity as that of the charged toner is applied on a toner outlet portion side of the return skeleton conveying member. A developing device.   6. The developing device according to claim 1, wherein a charged toner is applied to an electrode wire layer on the developing skeleton carrying member side of the return skeleton carrying member more than other electrode wire layers. A developing device characterized in that a pulsed voltage that causes a large rebound flight is applied.   7. The developing device according to claim 6, wherein a pulsed voltage applied to an electrode line layer on the developing skeleton conveying member side of the return skeleton conveying member is applied to the other electrode line layers. A developing device having a voltage value higher than that of a pulse voltage, a time for attracting toner, or a high frequency.   8. The developing device according to claim 1, wherein a toner outlet portion of the return skeleton conveying member is close to the developing skeleton conveying member side.   9. The developing device according to claim 1, wherein an insulating protective film is formed on a surface of the electrode wire of the skeleton transport member.   10. The developing device according to claim 1, wherein a bias voltage applied to a toner supply member that supplies toner to the developing skeleton conveying member is adjusted based on a toner density detection result. apparatus.   11. The developing device according to claim 1, wherein the image carrier is disposed to face the transport surface of the developing skeleton transport member.   A process cartridge comprising an image carrier, at least one of a charging unit, a cleaning unit, and the developing device according to any one of claims 1 to 10, and detachable from an image forming apparatus main body. .   13. An image forming apparatus for developing a toner by attaching toner to a latent image formed on an image carrier, comprising the developing device according to claim 1 or the process cartridge according to claim 12. An image forming apparatus. An image forming apparatus for forming a color image, comprising: a plurality of process cartridges according to claim 12.

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