JP2005062808A - Toner supply device, toner transporting device, developing device, processing unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which enable such a situation restrained that faultily electrified toner is supplied to a toner electrostatic transporting member such as a toner electrostatic transporting base plate for transporting toner by an EH phenomenon. <P>SOLUTION: The developing device 100 developing a latent image on a photoreceptor 11 by transporting toner to a developing area by a 1st toner electrostatic transporting base plate 101 is provided with a toner supply part 140 separating the toner from the mixture of the toner and friction accelerating substance in the 1st storage chamber 142 by a mesh 146 and supplying the toner to the base plate 101 while stirring the mixture in the 1st and 2nd storage chambers 142 and 143 in which the mixture is stored. Moreover, the developing device 100 is also provided with a toner replenishment part 160 having a toner storage part 141 in which toner for replenishment is stored, a feed roller 162 feeding the toner stored in the storage part 141 toward the supply part 140, and an electrifying means electrifying the toner before the toner is fed out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner supply device that supplies toner toward a toner electrostatic conveyance member that conveys the toner on the surface relative to the surface by electrostatic force, and a toner conveyance device and a development device using the toner supply device. The present invention relates to a process unit and an image forming apparatus.

  Conventionally, there are known image forming apparatuses such as copying machines, facsimile machines, and printers described in Patent Document 1 and Patent Document 2. In these image forming apparatuses, toner carried on a developer carrying member such as a developing roller that moves on the surface is transported to a developing position that is opposed to the latent image carrying member such as a photosensitive member, and the toner image is transferred onto the latent image carrying member. The electrostatic latent image is developed. In such a configuration, the toner rubs between the developer carrying member whose surface moves and the latent image carrying member, and adheres to one of the surfaces, which may adversely affect the image. Further, at the development position, the toner is electrostatically moved by the potential difference between the surface of the developer carrying member and the electrostatic latent image on the latent image carrying member, but this potential difference has to be considerably increased. Prior to the start of electrostatic movement, it is necessary to give the toner a force that overcomes the adhesion force between the toner and the developer carrying member due to van der Waals force, mirror image force, etc., and to solve the adhesion state. This is because electrostatic force is required.

  On the other hand, as an image forming apparatus that develops a toner image without using a developer carrier that moves on the surface, the one described in Patent Document 3 is known. The developing device of this image forming apparatus causes an EH (Electrostatic Transport & Hopping) phenomenon on the surface of the electrostatic toner transport substrate having a plurality of electrodes arranged at a predetermined pitch, and transports the toner to the developing position. The EH phenomenon is a phenomenon in which the energy of the phase-shift electric field acting on the powder is converted into mechanical energy and the powder itself dynamically changes. The toner in which the EH phenomenon has occurred jumps on the surface of the electrostatic transport substrate with a component in the traveling direction due to the phase-shift electric field, and moves in the direction of the substrate surface (transport) and moves in the direction perpendicular to the substrate surface ( Hopping). By transporting the toner to the development position while hopping the toner on the electrostatic electrostatic transport substrate, it is possible to realize low-potential development that cannot be realized with a configuration using a developer carrier that moves on the surface. For example, toner can be selectively attached to an electrostatic latent image having a potential difference of only a few tens [V] with respect to surrounding non-image portions.

JP-A-9-197781 JP-A-9-329947 JP 2002-341656 A

  However, the developing device of this image forming apparatus cannot supply sufficiently charged toner to the electrostatic toner transport substrate, and there is a risk of causing an adverse effect due to poor charging of the toner. Specifically, after the toner in the toner hopper is pumped up to the surface of the charging roller, it is rubbed and charged by the regulating blade, but this level of friction may be insufficient.

  Accordingly, the inventors of the present invention mix the toner with a friction promoting material composed of friction promoting particles such as glass beads and stir the mixture to sufficiently charge the friction before supplying the toner to the electrostatic electrostatic transport substrate. A new toner supply device is under development. The toner supply device includes a mixture container that contains the mixture, a stirring and conveying member such as a rotating screw member disposed therein, and a mesh provided on a part of the bottom surface of the mixture conveying path. And have. The toner container also has a toner supply device for replenishing new toner in the mixture container. In the process of transporting the mixture in the mixture container while being stirred by the stirring and transporting member, frictional charging of the toner inside is promoted. Then, when passing above the mesh, the toner is attracted toward the mesh by the electric field, and is discharged toward the electrostatic toner transport substrate through the opening of the mesh. In such a configuration, the toner can be supplied to the toner electrostatic transfer substrate after the toner is more reliably frictionally charged with the friction promoting substance.

  However, this developing apparatus has the following new problem. That is, a large amount of uncharged toner is spilled from the mesh immediately after replenishing new toner from the toner supply device to the mixture container in accordance with the amount of toner decrease due to the supply to the electrostatic toner transport substrate. It is a problem.

  Thus, as a result of intensive studies to cope with this new problem, the present inventors have found the following. That is, in the above-mentioned mixture container, the friction promoting particles such as glass beads are electrostatically adsorbed on the surface if the toner is very slightly charged, and the toner is several (1-2) thick. Form a layer. Then, the toner on the surface is frictionally charged satisfactorily by rubbing with other friction promoting particles on which the toner layer is formed. However, since the toner newly supplied from the toner supply device to the mixture container is hardly charged, it cannot be electrostatically adsorbed on the surface of the friction promoting particles. Then, a large amount stays in the gap between the friction promoting particles and is transported to the upper side of the mesh without being charged, and spills from the opening of the mesh by its own weight.

  Heretofore, the problems in the configuration in which the toner is separated from the mixture by the mesh have been described. However, even when the toner is electrostatically adsorbed on the friction promoting particles by an electrostatic force generated by an electric field, the toner with poor charging may be dropped from the opening of the mixture container. is there.

  The present invention has been made in view of the above background, and an object thereof is to provide the following toner supply device, and a toner conveying device, a developing device, a process unit, and an image forming device using the same. Is to provide. That is, a toner supply device or the like that can suppress a situation in which a toner with poor charging is supplied to a toner electrostatic conveyance member such as a toner electrostatic conveyance substrate that conveys toner by the EH phenomenon.

In order to achieve the above object, a first aspect of the present invention is directed to a toner supply device that supplies toner to a toner electrostatic conveying means that conveys the toner on the surface by moving it by electrostatic force. A mixture container that contains a mixture in which a triboelectrically charged substance that promotes charging is mixed; a stirring unit that stirs the mixture in the mixture container; and a toner and a friction promoting substance that mixes the mixture stirred by the stirring unit. A separating means for separating the toner, a supply means for supplying the toner separated by the separating means to the electrostatic toner conveying means, a toner containing portion for containing replenishing toner, and a toner containing portion in the toner containing portion Feeding means for feeding the toner to the supply means and replenishing the toner before or while being fed into the toner container In which characterized in that a supply means having a charging allowed to charging means.
According to a second aspect of the present invention, in the toner supply apparatus of the first aspect, the charging means is a unit that charges the toner particles by charge injection.
According to a third aspect of the present invention, in the toner supply apparatus of the first aspect, the charging means is one that charges the toner particles by corona discharge.
According to a fourth aspect of the present invention, in the toner supply apparatus of the first aspect, the charging means is one that charges the toner particles by electron field emission.
According to a fifth aspect of the present invention, in the toner supply device of the first aspect, the charging means is one that charges the toner particles by friction.
According to a sixth aspect of the present invention, in the toner supply device according to any one of the first to fifth aspects, the charging is performed so that the absolute value of the average charge amount of the toner particles is 1.0 [μC / g] or more as the charging unit. It is characterized by the use of abilities.
According to a seventh aspect of the present invention, in the toner supply device according to any one of the first to sixth aspects, as the feeding means, the toner carrying that replenishes the replenishment destination by driving while carrying the toner in the toner containing portion. In addition to using a member, as the charging means, a device that charges the toner carried on the toner carrying member is used.
Further, the invention of claim 8 is a toner supply device for supplying toner to a toner electrostatic transport means for transporting the toner on the surface by moving it by electrostatic force. A mixture container that contains the mixture in which the substances are mixed, a stirring unit that stirs the mixture in the mixture container, and a separating unit that separates the mixture stirred by the stirring unit into toner and a friction promoting material; A supply unit that supplies the toner separated by the separation unit to the electrostatic toner transport unit, a toner storage unit that stores replenishment toner, and the supply unit that supplies the toner in the toner storage unit A replenishing means having a replenishing means for replenishing and replenishing the toner, and having charged the toner charged together with the main body prior to factory shipment. It is an butterfly.
According to a ninth aspect of the present invention, there is provided a toner supply device for supplying toner to a toner electrostatic transport means for transporting the toner on the surface by electrostatic force. A mixture container that contains the mixture in which the substances are mixed, a stirring unit that stirs the mixture in the mixture container, and a separating unit that separates the mixture stirred by the stirring unit into toner and a friction promoting material; A supply unit that supplies the toner separated by the separation unit to the electrostatic toner transport unit, a toner storage unit that stores replenishment toner, and the supply unit that supplies the toner in the toner storage unit And a replenishing means for replenishing and replenishing the toner, the toner to be set in the toner container is charged in advance prior to factory shipment and It is characterized in that specify what mainly composed of the toner particles used expiration date stipulated.
The invention according to claim 10 is the toner supply device according to claim 8 or 9, wherein an absolute value of an average charge amount of toner particles in the toner before the expiration date of use is 1.0 [μC / g] or more.
According to an eleventh aspect of the present invention, there is provided a toner conveying apparatus comprising: a toner electrostatic conveying unit that conveys the toner on the surface by electrostatic force; and a toner supply unit that supplies the toner to the toner electrostatic conveying unit. The toner supply device according to any one of claims 1 to 10 is used as the toner supply means.
According to a twelfth aspect of the present invention, in the toner conveying device of the eleventh aspect, as the separating means, a toner and the friction promoting substance mainly composed of friction promoting particles having a larger average particle diameter than the toner are meshed. It is characterized by using what is separated by.
The invention according to claim 13 is the toner conveying device according to claim 12, wherein the mixture is transferred to the surface of the mesh by rotating the screw member having a spiral projection formed on the peripheral surface of the rotating shaft as the stirring means. What stirs while conveying in the direction is used.
According to a fourteenth aspect of the present invention, in the toner conveying device according to the thirteenth aspect, the toner supply device according to the seventh aspect is used, and a helical groove is formed on a peripheral surface of a rotatable roller member as the toner carrying member. In which the toner filled in the groove is replenished into the mixture housing portion, and the screw member has a pitch in the axial direction of the spiral projection as the axial direction of the groove in the toner carrying member. What is characterized by using the same pitch as in the above.
According to a fifteenth aspect of the present invention, in the toner conveying device of the thirteenth aspect, the toner supply device according to the seventh aspect is used, and as the toner carrying member, a raised brush is spirally formed on a peripheral surface of a rotatable rotation shaft And the screw member having the same pitch in the axial direction of the spiral protrusions as that of the spiral raising in the toner carrying member is used. It is a feature.
According to the sixteenth aspect of the present invention, the toner existing on the surface of the electrostatic toner conveying means provided in the toner conveying means is conveyed to a position facing the latent image carrier while being moved by electrostatic force, and the latent image is conveyed. In the developing device for contributing to the development of the latent image carried on the image carrier, the toner carrying device according to any one of claims 11 to 15 is used as the toner carrying means.
According to a seventeenth aspect of the present invention, at least a latent image carrier that carries a latent image in the image forming apparatus and a developing unit that develops the latent image on the latent image carrier are shared as one unit. In the process unit supported by the support, the developing device according to claim 16 is used as the developing means.
According to an eighteenth aspect of the present invention, there is provided an image forming apparatus comprising a latent image carrier that carries a latent image and a developing unit that develops the latent image on the latent image carrier. The developing device is used.

  In these inventions, the toner supply device replenishes the supply means with the toner charged by the charging means of the replenishment means or the toner charged in advance prior to factory shipment. In the supply means, the replenished toner is electrostatically adsorbed on the surface of the friction promoting particles in the mixture storage means even if the charge amount is small. Then, after being agitated by the agitating means and charged well, it is supplied to the electrostatic toner transporting member. Accordingly, there is an excellent effect that it is possible to suppress a situation in which the toner with poor charging is supplied to the electrostatic toner conveying member that conveys the toner by the EH phenomenon.

  A first embodiment in which the present invention is applied to a laser copying machine (hereinafter simply referred to as a copying machine) that is an electrophotographic image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram showing a copying machine according to the first embodiment. A scanner device having a contact glass 1, a scanning optical system 2, and the like is provided on the upper portion of the copying machine main body. After a document is placed on the contact glass 1, when a copy start button (not shown) is pressed, reading of the document by the scanner device is started. Specifically, the original on the contact glass 1 is optically scanned while the moving unit having the original illumination light source 3, the reflection mirrors 4, 5, 6 and the like moves in the original surface direction. The document reflected light obtained by this optical scanning passes through the lens 7 and then is read as an image signal by the image reading element 8 to be subjected to digital image processing. The processed signal drives a laser diode (LD) (not shown) to emit laser light. The emitted laser light scans the photoconductor 11 via the mirror 10 while being reflected on the polygon mirror 9 and deflected in the main scanning direction. Prior to this scanning, the drum-shaped photoconductor 11 is uniformly charged by the drum charger 12 while being driven to rotate clockwise in the drawing by a driving means (not shown). Then, the above-mentioned laser beam is scanned on the surface to carry an electrostatic latent image. This electrostatic latent image is developed into a toner image by the developing device 100.

  A charger unit faces the photoconductor 11 from below in the figure. Two sheet feeding cassettes 13 and 14 are arranged on the left side of the charger unit in the drawing, and each cassette accommodates a plurality of transfer sheets P as recording bodies in a state of a stack of transfer sheets. . When the copy operation is started, the paper feed roller (13a or 14a) of the paper feed cassette (13 or 14) containing the transfer paper P having the size and orientation corresponding to the image information is driven to rotate, and the transfer paper bundle The uppermost transfer paper P is sent out to the paper feed path, and a registration roller pair 15 is disposed on the most downstream side of the paper feed path, and the transfer paper P sent from the paper feed means is used as a roller. Then, at a timing at which the sandwiched transfer paper can be superimposed on the toner image on the photoconductor 11, it is sent out toward the facing portion between the photoconductor 11 and the charger unit. The toner image on the photoconductor 11 is electrostatically transferred to the transfer paper P by the influence of corona discharge generated from the transfer charger 16. Thereafter, the separation charger 17 removes the toner image from the photoconductor 11. The separated transfer paper P is sent to a fixing unit 19 by a conveying belt 18 that is endlessly moved while being stretched by a stretching roller, which includes a heating roller having a heat source therein and a predetermined pressure. The toner image is fixed while being heated by being sandwiched between the fixing nip formed by the pressure roller that is in contact with the toner, and the toner image is fixed on the transfer paper P by the influence of the heating and pressure. The transfer sheet P on which the toner image is fixed is stacked on the stack unit 21 outside the apparatus through the pair of discharge rollers 20.

  After passing through the position facing the charger unit, the transfer residual toner adhering to the surface of the photoconductor 11 is removed by the cleaning unit 22 and then is neutralized by the neutralizing lamp 23 to be initialized.

  FIG. 2 is an enlarged configuration diagram showing the photoreceptor 11 and the first toner electrostatic transfer substrate 101 of the developing device (100). In the developing device (100), toner is supplied onto the first toner electrostatic transport substrate 101 from a supply unit described later in a region (not shown). The first toner electrostatic transport substrate 101 is arranged such that a plurality of strip-shaped transport electrodes are arranged at a predetermined pitch in the longitudinal direction of the substrate (left and right in the figure) with respect to an insulating substrate 101d made of glass or the like. ing. These transport electrodes have a width dimension (dimension in the longitudinal direction of the substrate) of 30 [μm], and are arranged in parallel via a gap of 30 [μm]. With such an arrangement, strip-like transport electrodes are arranged in stripes on the insulating substrate.

  In more detail about each conveyance electrode, they are classified into three types, A group, B group, and C group, and the electrodes belonging to the same group are in an electrically connected state. On the insulating substrate 101d, each transport electrode is repeated so that the order of the A transport electrode 101a belonging to the A group, the B transport electrode 101b belonging to the B group, and the C transport electrode 101c belonging to the C group is repeated on the left side in the drawing. Is arranged. An A-phase drive bias, a B-phase drive bias, and a C-phase drive bias are applied from the drive power supply circuit 30 to each A transport electrode 101a, each B transport electrode 101b, and each C transport electrode 101c. In the figure, the toner is negatively charged and is transported on the first toner electrostatic transport substrate 101 from the right side to the left side in the figure.

  FIG. 3 is a waveform diagram showing waveforms of the above-described A-phase drive bias, B-phase drive bias, and C-phase drive bias. In each phase, DC pulse waves having a voltage of −100 [V] and a duration of 501 [μsec] are output at intervals of 501 [μsec]. Here, when paying attention to the C-phase drive bias applied to the C transport electrode (101c), it is 0 [V] at time t0. At this time, the A transport electrode (101a) adjacent to the C transport electrode (101c) on the upstream side in the toner transport direction is also 0 [V] (see C-phase drive pulse). Further, a voltage of −100 [V] is applied to the B transport electrode (101a) adjacent on the downstream side in the toner transport direction (see B-phase drive bias). In such a state, the toner on the C transport electrode (101c) at the time point t0 hardly remains moving and remains there.

  Thereafter, when 334 [μsec] elapses and the time point t1 arrives, a voltage of −100 [V] is applied to the C transport electrode (101c). Then, an electrostatic force repelling the C transport electrode (101c) acts on the negative polarity toner existing on the C transport electrode (101c). At this time, a voltage of −100 [V] is also applied to the A transport electrode (101a) adjacent to the C transport electrode on the upstream side in the toner transport direction. On the other hand, the B transport electrode (101b) adjacent on the downstream side in the toner transport direction is 0 [V]. For this reason, the negative polarity toner present on the C transport electrode (101c) is electrostatically moved toward the B transport electrode (101b).

  Thereafter, when about 334 [μsec] elapses and the time point t2 arrives, a voltage of −100 [V] is applied to the B transport electrode (101b) which has been 0 [V] until then. Then, an electrostatic force repelling the B transport electrode (101b) acts on the toner that has come to exist on the B transport electrode (101b) due to electrostatic movement from the C transport electrode (101c). . At this time, a voltage of −100 [V] is also applied to the C transport electrode (101c) adjacent to the B transport electrode (101b) on the upstream side in the toner transport direction. On the other hand, the A transport electrode (101a) adjacent on the downstream side in the toner transport direction is 0 [V]. For this reason, the toner on the B transport electrode (101b) is electrostatically moved toward the A transport electrode (101a).

  After that, when about 334 [μsec] elapses and time t3 arrives, a voltage of −100 [V] is applied to the A transport electrode (101a) that has been 0 [V] until then. Then, an electrostatic force that repels the A transport electrode acts on the toner that has been present on the A transport electrode (101a) due to electrostatic movement from the B transport electrode (101b). At this time, a voltage of −100 [V] is also applied to the B transport electrode (101b) adjacent to the A transport electrode (101a) on the upstream side in the toner transport direction. On the other hand, the C carrying electrode (101c) adjacent on the downstream side in the toner carrying direction is 0 [V]. For this reason, the toner on the A transport electrode (101a) moves electrostatically toward the C transport electrode (101c).

  By repeating the electrostatic movement as described above, in FIG. 2 described above, the toner on the first toner electrostatic transport substrate 101 moves electrostatically while hopping from the right side to the left side in the figure. Then, the first toner electrostatic transfer substrate 101 and the photoconductor 11 enter a developing area where they face each other with a predetermined gap. In this developing area, the image portion 11a of the photoreceptor 11 is 0 [V], while the non-image portion 11b is −100 [V]. Then, the toner adheres to the image portion 11a of the photoconductor 11 and develops the electrostatic latent image in the process of electrostatically moving in the developing area from the right side to the left side in the drawing.

  The non-image portion 11b of the photosensitive member 11 needs to have a larger potential on the toner charging polarity side than the average potential value of the driving bias applied to each transport electrode of the first toner electrostatic transport substrate 101. is there. For example, the driving bias of each phase shown in FIG. 3 is a repetition of a potential of −100 [V] with a duration of 501 [μsec] and a potential of 0 [V] with a duration of 501 [μsec]. Therefore, the potential average value becomes −50 [V]. On the other hand, the potential of the non-image portion 11b of the photoconductor 11 in FIG. 2 is −100 [V] which is larger on the negative polarity side than −50 [V]. In such a potential relationship, toner existing between the first toner electrostatic transport substrate 101 and the non-image portion 11b of the photosensitive member 11 in the development region is relatively directed toward the first toner electrostatic transport substrate 101. Therefore, adhesion to the non-image portion 11b is prevented. However, if the potential of the non-image portion 11b is made smaller than the average value of the drive bias potential to the negative polarity side, the toner may be electrostatically moved toward the non-image portion 11b and attached. is there. Therefore, the potential of the non-image area 11b is set larger than the potential average value of the drive bias toward the charging polarity side of the toner.

Next, a characteristic configuration of the copying machine will be described.
FIG. 4 is an enlarged configuration diagram showing the developing device 100 and the photoconductor 11. In FIG. 1, the developing device 100 includes a toner conveying unit 120 that circulates and conveys toner in the vicinity of the photoreceptor 11, a toner supply device that supplies toner toward the toner conveying unit 120, and the like. This toner supply device includes a toner supply unit 140 and a toner supply unit 160 that supplies toner to the toner supply unit 140.

  5, 6 and 7 are a plane sectional view, a longitudinal sectional view and a transverse sectional view showing the toner supply unit 140, respectively. The toner supply unit 140 includes a storage chamber that is a mixture storage unit that stores a mixture of toner and a friction promoting substance (not shown). The storage chamber is divided into a first storage chamber 142 and a second storage chamber 143 by a partition wall 141. It is divided into two. In the first storage chamber 142, a first transfer screw 144 that is rotationally driven by a driving unit (not shown) is provided. In the second storage chamber 143, a second transfer screw 145 that is rotationally driven by a driving unit (not shown) is provided. The first transport screw 144 and the second transport screw 145 have a structure in which spiral protrusions 144b and 145b are projected from the surfaces of the rotating shafts 144a and 145a. The screw pitch is 120 [mm] and the thickness of the spiral protrusion is 1.5 [mm], respectively. The rotating shafts 144a and 145a are rotated so that the tips of the spiral protrusions 144b and 145b are moved at a peripheral speed of 60 [mm / sec]. In each screw, the surface of a base material made of a conductive material such as aluminum is coated with a polyimide resin layer having a thickness of about 1 [μm].

  In the vicinity of both ends of the storage chamber, there is a communication space where the partition wall 141 is not provided over a length L2 (for example, 25 mm), and the two storage chambers (142, 143) communicate with each other. In FIG. 5, the first conveying screw 144 stirs and conveys the mixture contained in the first accommodation chamber 142 from the left side to the right side in the drawing as it is rotationally driven by a screw drive system (not shown). . Thus, the mixture conveyed to the communication space on the right side of the first storage chamber 142 in the drawing enters the second storage chamber 143. Then, it is conveyed from the right side in the drawing to the left side by the second conveyance screw 143 that is rotationally driven by the screw drive system, and passes through the communication space on the left side in the drawing of the second accommodation chamber 143, so that the first accommodation chamber 142 Return inside. In this manner, the mixture circulates counterclockwise in the drawing while being stirred and conveyed in the storage chamber. The second storage chamber 143 is provided with a toner concentration detection unit (not shown), detects the toner concentration of the mixture in the second storage chamber 143, and outputs a toner concentration signal to a supply control unit (not shown). The replenishment control unit drives and controls the toner replenishing unit (160 in FIG. 4) in accordance with the toner density signal to replenish the first storage chamber 142 with an appropriate amount of toner. Thereby, the toner concentration of the mixture in the storage chamber is maintained within a predetermined range. The toner newly replenished in the second storage chamber 143 is taken into the mixture, and then sent to the first storage chamber 142 while being rubbed against the friction promoting material along with the agitation transport.

  As shown in FIG. 6, a mesh 146 is provided at the bottom of the first storage chamber 142. In the first storage chamber 142, the mixture passes over the mesh 146 while being stirred and transported by the first transport screw 144. The mesh 146 has a metal plate-like member made of stainless steel having a thickness of 0.08 [mm], and a plurality of holes having a major axis of 0.2 [mm] and a minor axis of 0.15 [mm] are about 50 [%]. ] So as to have an aperture ratio of Each hole is provided in such a posture that its minor axis direction is along the screw axis direction. A predetermined gap is held between the tip of the spiral protrusion 144 b of the first transport screw 144 and the mesh 146. This gap is desirably set in a range of about 1/5 to 10 times the diameter of the toner. Desirably, when the carrier diameter is about 1/3 to 2 times the carrier diameter, the mixture replacement efficiency and the mixing and stirring efficiency are improved. In the copying machine according to the first embodiment, it is set to about 0.7 to 1.0 [mm]. It is desirable to provide a predetermined gap between the tip of the spiral protrusion 144b of the first transport screw 144 and the mesh 146.

  As shown in FIG. 7, a screw power circuit 190 is connected to the conductive base material of the first transport screw 144. A mesh power supply circuit 191 is connected to the mesh 146. Each of these power supply circuits generates a negative polarity potential in the screw or mesh, and the output voltage is controlled by a main control unit (not shown). When the toner is supplied from the toner supply unit 140 to the above-described toner transport unit (120) (not shown), the first transport screw 144 and the mesh 146 are charged with the same polarity as the toner by the outputs from these power supply circuits. . Specifically, the first conveying screw 144 has a larger potential on the same polarity side (minus polarity side) as the toner than the mesh 146. Further, the mesh 146 has a larger potential on the same polarity side as the toner than the average voltage value of the drive bias applied to each transport electrode of the first toner electrostatic transport substrate (101) (not shown). More specifically, for example, when the average voltage value of the drive bias is −50 [V] as described above, the first conveying screw 144 and the mesh 146 are −1.45 [kV] and −0.25 [ kV].

  Then, an electric field as shown in FIG. 8 is formed from the first storage chamber 142 to the first toner electrostatic transfer substrate (101) (not shown). That is, a line of electric force extending from the tip of the screw spiral projection 144b toward the hole 146a of the mesh 146 is formed between the first conveying screw (144) and the mesh 146. In addition, electric lines of force extending from the vicinity of the exit of the hole 146a toward the substrate are formed between the mesh 146 and the first toner electrostatic transfer substrate (101) (not shown). The toner in the mixture that is agitated and conveyed by the first conveying screw (144) is first removed from the surface of the frictionally charged particles and electrostatically moved into the hole 146 under the influence of the former lines of electric force. Next, after passing through the hole 146 under the influence of the latter lines of electric force, it electrostatically moves toward the first toner electrostatic transfer substrate (101). By such electrostatic movement, the toner in the mixture stirred and conveyed in the first storage chamber 142 shown in FIG. 7 is separated from the frictionally charged material and supplied to the first toner electrostatic conveyance substrate (101). The The toner after passing through the mesh 146 is relatively moved in the toner transport direction on the substrate while being relatively electrostatically moved toward the transport electrodes on the substrate having an average voltage value smaller than the potential of the mesh 146. Electrostatic movement.

  The potential difference between the tip of the spiral protrusion 144b of the first conveying screw 144 and the mesh 146 is set so that the electric field strength between the two is within the range of 0.3 to 3.5 [kV / mm] in absolute value. Is desirable. This is because if it exceeds 3.5 [kV / mm], the electric lines of force extending from the spiral protrusion 144b are concentrated on the edge of the hole 146a, and it becomes easy to cause discharge from the screw to the mesh. On the other hand, when it becomes smaller than 0.3 [kV / mm], an electrostatic force larger than the adhesion force (image force or van der Waals force) is applied to the toner adhering to the surface of the friction promoting particles. Because it becomes impossible. When the distance between the tip of the spiral protrusion 144b and the mesh 146 is 1 [mm], the electric field strength can be kept within the above range by setting the potential difference between the two to an absolute value of 0.3 to 3.5 [kV]. be able to. A more desirable range of the electric field strength is 0.8 to 3.0 [kV] in absolute value.

  As shown in FIG. 7, no mesh is provided at the bottom of the second storage chamber 143. Therefore, only the toner in the first storage chamber 142 out of the two storage chambers is supplied to the first toner electrostatic transfer substrate 101.

  In FIG. 4 described above, the toner transport unit 140 includes a second toner electrostatic transport substrate 103 in addition to the first toner electrostatic transport substrate 101 described above. Then, a transfer unit 102 having the first toner electrostatic transport substrate 101 as a bottom surface and a recovery unit 104 having the second toner electrostatic transport substrate 103 as a bottom surface on the lower side in the gravitational direction are overlapped. It has a structure. The toner that passes through the mesh 146 and is supplied to the right end of the first toner electrostatic transfer substrate 101 of the toner transfer unit 140 in the drawing is transferred from the right to the left in the drawing while hopping due to the EH phenomenon. . A part of the development area facing the photoconductor 11 contributes to the development of the electrostatic latent image. The remaining toner that wanted to contribute to the development passes through the development area and then falls onto the left end portion of the second toner electrostatic conveyance substrate 103 in the drawing. The second toner electrostatic transport substrate 103 also has a plurality of transport electrodes similar to the first toner electrostatic transport substrate 101. The toner dropped on the left end portion of the second toner electrostatic transfer substrate 103 in the figure is affected by the drive pulses of the A to C layers applied to the transfer electrodes, and this time, hops from the left side to the right side in the figure. While being conveyed. Then, the toner is returned to the second storage chamber of the toner supply unit 140. Thereby, the toner that has not contributed to the development is recycled.

  A toner supply unit 160 is detachably connected to the second storage chamber 143 of the toner supply unit 140. The toner replenishing unit 160 is driven and controlled by the above-described replenishment control unit to replenish toner contained therein into the second storage chamber 143.

  In the developing device 100 configured as described above, a toner transport unit is configured by a combination of the toner transport unit 120, the toner supply unit 140, and the toner replenishment unit 160. The toner conveying means is a photosensitive member 11 as a latent image carrier while causing toner existing on the surface of the first toner electrostatic conveying substrate 101 as a toner electrostatic conveying member to move relative to the surface by electrostatic force. It is a means to convey to the position facing. Further, in the developing device 100 of the present copying machine, the first storage chamber 142 and the second storage chamber 143 contain a mixture containing a mixture in which a frictionally charged substance that promotes frictional charging of toner is mixed. Is functioning as Moreover, the combination which consists of the 1st conveyance screw 144, the 2nd conveyance screw 145, the rotational drive system which rotationally drives these, etc. is functioning as the stirring means which stirs the mixture in a mixture accommodating part. A combination of the mesh 146, the screw power supply circuit (190), the mesh power supply (191), and the like functions as a separating unit that separates the mixture stirred by the stirring unit into toner and a friction promoting substance.

The mesh 146 made of a metal material can be easily manufactured by etching a metal film (plate) or electrohoming (electroforming). FIGS. 9A, 9B, and 9C show an example of a mesh forming process by etching. In this example, first, as shown in FIG. 9A, an opening pattern of a photomask obtained by performing fine processing by laser processing on a metal film such as SUS is formed by a photoresist. Next, as shown in FIG. 9B, etching is performed with FeCl ₃ or the like to form holes. Further, as shown in FIG. 9C, the resist film is peeled off to complete the mesh 146. In addition, what is necessary is just to perform a mesh formation by electrohoming by the process as shown to Fig.10 (a) and (b). It is also possible to form the mesh 146 by knitting a fine wire.

  As a material for the mesh 146, it is desirable to use a material that exhibits flexibility and wear durability. Moreover, the shape of the hole of the mesh 146 can employ a round shape, an oval shape, a square shape, a rectangular shape, a star shape, an irregular shape, or the like. In this copying machine, as shown in FIG. 9C, the mesh hole has an elliptical shape, the length of the opening in the longitudinal direction is the length L of the hole, and the size of the opening in the short direction is the hole size. The width is W.

  The thickness T of the mesh 146 is desirably set in the range of 20 to 150 [μm], preferably 30 to 80 [μm]. At this time, it is preferable that the relationship between the thickness T, the length L, and the width W is in a range of 500 W ≧ L and W / 5 ≦ T ≦ 3W. This is because when the length L of the hole and the width W are 500 W ≧ L, the mesh 146 has both a certain degree of rigidity and a certain degree of high aperture ratio. Further, when the relationship between the width W and the thickness T is W / 5 ≦ T ≦ 3W, it is possible to ensure flatness and curvature processing as a metal film. Thereby, the bobbin shape, the straightness of the flat plate, the contact deformation, and the shape recovery due to the rigidity of the mesh 146 can be functioned.

  The opening ratio of the mesh 146 is preferably in the range of 20 to 70 [%]. This is because, when an image to be developed is solid black, it has been confirmed by experiments that it must be within such a range in order to ensure the discharge amount without unevenness.

  The hole 146a of the mesh 146 needs to be larger than the average particle diameter r of the toner and smaller than the average particle diameter R of the friction promoting particles P. Further, the relationship between the toner shown in FIGS. 11A and 11B and the friction promoting particles P is preferably 6r ≦ W and 2W ≦ R. By setting 6r ≦ W with respect to the average particle diameter r of the toner, clogging of the mesh with the cloud-like toner is less likely to occur, and the toner can be continuously supplied easily through the hole 146a. Further, by setting 2W ≦ R with respect to the average particle R of the friction promoting particles P, the particle size distribution of the friction promoting particles P, and when the friction promoting particles P are worn and reduced in size by continuous use, A margin is provided so that the mesh 146 does not pass through the holes.

  Regarding the structure of the mesh 146, in addition to the metal material, as shown in FIG. 12, the surface facing the first toner electrostatic transfer substrate 101 is made of the metal material layer 146b, and the contact surface with the mixture is made of the organic resin 146c. It is good also as a double structure. In the mesh 146 having such a structure, the portion in contact with the friction promoting particles P is made of an organic material, so that the damage to the friction promoting particles P due to friction is smaller than that of the metal material, and the durability can be improved.

  As shown in FIG. 13, the holes 146a of the mesh 146 may be configured to taper from the entrance side where the toner enters to the exit side. With this structure, it is possible to reliably extend the lines of electric force from the metal material portion (146b) on the inner wall of the hole 146a toward the first toner electrostatic transfer substrate (101) (not shown) on the outlet side. As a result, the toner can be easily removed from the hole 146a.

As for the mesh 146, as shown in FIG. 14, the surface of a base 146d made of a metal material may be covered with an insulating protective film 146e. In this case, the protective film 146e is a thin film having a thickness of 0.5 to 30 [μm] so as not to cause deterioration of the electric field strength, and a material such as SiO ₂ , SiN, Ta ₂ O ₅ , or polyimide is used. In the mesh 146 having such a configuration, the surface in contact with the charged toner is entirely covered with the insulating protective film 146e, so that charge injection from the base 146d to the toner can be prevented and the charge amount can be kept appropriate. Can do. In addition, since the substrate 146d and the mixture do not come into contact with each other, the deterioration of the mixture, particularly the toner, can be reduced as compared with that in contact with the metal part.

  Further, as shown in FIG. 15, the mesh 146 may be formed by coating the outer surface of a base 146f made of an organic resin material with a metal layer 146g made of a metal material by vapor deposition or electroforming. In this case, as the organic resin material used for the base 146f, it is desirable to use a material having a relatively high toner charging capability. The metal layer 146g is a thin film having a thickness of 0.5 to 5 [μm], and the toner in the hole 146a passes through the hole along the electric lines of force extending from the thin film toward the first toner electrostatic transfer substrate 101. pass. In the mesh 146 having such a configuration, since the base body 146f is an organic resin material, it exhibits excellent flexibility and elasticity, and also exhibits shape restoring properties. And even when force is applied from the outside, the shape can be kept stable. In addition, frictional charging of the toner can be promoted by contacting the toner in the hole 146a.

  Further, as shown in FIG. 16, the mesh 146 may have a protective layer 146i made of an organic resin agent bonded to the screw facing surface side of the base material 146h made of a metal material. In this case, it is desirable to use an organic resin material having a relatively high toner charging capability. As for the bonding method of both materials, a method by heat bonding or a method by hot pressing can be used. The mesh 146 using an organic resin material can exhibit good flexibility, elasticity, and shape restoration.

  Further, as shown in FIG. 17, the mesh 146 may have a tapered shape that widens from the entrance side where the toner enters toward the exit side. You may form in a shape which has an inclination toward an outer surface and a hole diameter spreads. By forming the slope extending toward the outlet side on the inner wall of the hole, toner adhesion to the inner wall can be suppressed.

  FIG. 18 is an enlarged configuration diagram showing the toner replenishing unit 160 together with the second conveying screw 145 of the toner supplying unit (140). In the figure, a toner replenishing section 160 includes a toner accommodating section 161 that accommodates toner for replenishment, a feeding roller 162 for feeding toner from the inside to the second conveying screw 145 of the toner supplying section, and a scraping blade. 163 etc. The feeding roller 162 is made of a highly conductive material such as metal. A part of the peripheral surface of the toner container 161 is disposed so as to be exposed from an opening provided in the casing 164, and is driven to rotate clockwise in the drawing by a driving unit (not shown). As shown in FIG. 19, a spiral groove 162 a dug in a spiral shape is formed on the peripheral surface of the feeding roller 162. The spiral groove 162a has a width of 1 [mm] and a depth of 0.2 [mm], and the spiral protrusion (145b) of the second conveying screw (145) below the feeding roller 162. And the pitch is equal. Then, the feeding roller 162 and the second conveying screw (145) are rotationally driven at equal circumferential speeds so that the spiral groove 162a and the spiral protrusion (145b) are always opposed to each other at the opposing portions. .

  In FIG. 18 shown above, the scraping blade 163 is a free end whose one end is fixed to the casing 164 while the other end is not fixed. The free end is disposed so as to contact the peripheral surface of the feeding roller 162. The toner stored in the toner storage unit 161 is pressed against the feeding roller 162 by its own weight, and a part of the toner is filled in the spiral groove 162a. In the feeding roller 162 in which the toner is filled in the spiral groove 162a in this manner, excessive toner adhering to the peripheral surface (non-groove portion) is made of urethane rubber in the process of rotating clockwise in the drawing. It is scraped off by the scraping blade 163. And it goes outside through the opening of the casing 164 and reaches the replenishment region which is the facing portion of the second conveying screw 145 located below. In this replenishment region, a predetermined gap is maintained between the peripheral surface of the feeding roller 162 and the tip of the spiral protrusion 145b of the second conveying screw 145.

  FIG. 20 is an enlarged view showing a peripheral configuration of a replenishment area formed between the toner replenishing section (106) and the toner supplying section (140). In the figure, the second conveying screw 145 has a protective layer made of an organic resin material on the surface of a base made of a metal such as aluminum. The metal base is electrically grounded. On the other hand, a feeding power supply circuit 192 whose output is controlled by a control unit (not shown) is connected to the feeding roller 162 made of a metal material. Due to the output from the feeding power supply circuit 192, the feeding roller 162 has a negative potential having the same polarity as the charging polarity of the toner. The potential value is, for example, −1.0 [kV].

  As the feeding roller 162 rotates, the toner filled in the spiral groove 162a of the feeding roller 162 is conveyed toward the replenishment area. In this replenishment region, a strong electric field is formed between the feeding roller 162 having a potential of −1.0 [kV] and the spiral protrusion 145a of the second conveying screw 145 that is grounded. The toner in the spiral groove 162a that has reached the replenishment region receives this strong electric field, is injected with a negative polarity charge from the feed roller 162, and flies out from the spiral groove 162a. Then, it passes through the gap G and adheres to the spiral protrusion 145 b of the second transport screw 145. In this way, toner is supplied from the toner supply unit 160 into the second storage chamber (143) of the toner supply unit 140. The replenished toner is stirred and conveyed toward the first storage chamber (142) while being mixed with the mixture in the second storage chamber. In this process, the toner is further promoted to be triboelectrically charged.

  Although the charge amount (Q / M) of the toner immediately after replenishment varies depending on the type of toner, according to the test by the present inventors, it was −2 to −7 [μC / g]. This value is still insufficient to make the toner contribute to the development, but is sufficient to electrostatically attract the triboelectrically charged particles in the mixture. The charge amount of the toner in the mixture conveyed to the upper side of the mesh (146) was increased to -15 to -30 [μC / g], and was a value that could sufficiently contribute to development. For reference, when a very small amount of charged toner of −1 [μC / g] is manually put into the second storage chamber of the toner supply unit (140), the toner still spills from the mesh (146). It hardly happened. Although slight spillage was observed, it was at a level that would not interfere with actual use. However, it was found that the amount of spillage suddenly increased when it became smaller than -1 [μC / g]. Therefore, if toner is charged to 1 [μc / g] or more in absolute value before replenishment, spillage can be effectively suppressed. For reference, the absolute value of the toner charge amount at which spillage is completely eliminated was 3 [μC / g].

  In FIG. 18 described above, the feeding roller 162 functions as a feeding unit that feeds the toner in the toner storage unit 161 toward the second transport screw 145 of the toner supply unit (140) that is the supply destination. ing. The combination of the feeding roller 162 and the feeding power supply circuit 192 functions as a charging unit that charges the toner before being fed by the feeding unit or in the middle of feeding.

  For reference, the principle of charge injection into toner that occurs in the replenishment area of the copier will be described. FIG. 21 is a cross-sectional view showing a main part of a flying device for flying toner between electrodes. In this flying device, a ground electrode 201 made of a grounded aluminum flat plate and a pulse applying electrode 202 made of an aluminum flat plate connected to a power supply circuit are opposed to each other by a bakelite spacer with a gap of 1.0 [mm]. . A cylindrical recess having a diameter of 10 [mm] × depth of 0.2 [mm] is formed on the upper surface of the ground electrode 201, and is filled with uncharged toner. When a voltage is applied to the pulse application electrode 202, a current having a polarity opposite to that of the pulse application voltage flows from the ground electrode 201 into the toner in the recess 201a due to the influence of the potential difference between both electrodes. As a result, the toner is injected with electric charge and flies against the gravity toward the pulse applying electrode 202 from the recess 201a.

  The present inventors performed the following tests using the flying device shown in FIG. That is, as the power supply circuit, a combination of a function generator FC-120 manufactured by Yokogawa Electric Corporation and a High-Voltage Power Amplifier 10 / 10A manufactured by Trek was used. This combination amplifies the square pulse emitted from the former 1000 times by the latter, and can change the output voltage value to the pulse application electrode 202. The output waveform to the pulse application electrode 202 is visually observed by a digital oscilloscope 243IL manufactured by Sony-Tektronix. The present inventors investigated the relationship between the pulse applied voltage value and the toner flying state using the flying device having such a configuration. As for the pulse application voltage, a square pulse generated from ± 0.2 V to 1.0 V and 1 to 1000 [msec] from the above-mentioned generator was amplified 1000 times and output to the pulse application electrode 202. It goes without saying that the toner is reset every time the voltage is changed.

  For the toner that flew and adhered to the pulse application electrode 202, the mass was measured with a suction type Faraday gauge METTTLER AT261 DeltaRange. In addition, the charge amount was measured with a Keithley System Electrometer Model 6514.

  As test toners, six types of commercially available toners A to F on the market and two types of prototype toners G to H prototyped by the present inventors were used. Both of these two types of trial toners consist only of a base resin and a pigment. Hydrophobic silica H-2000 (manufactured by Hoechst) is added to the toner base powder before the addition of an external additive such as a charge control agent or silica by an Osterizer using 1.0 [wt%] (G), 3.0 [ wt%] (H).

  FIG. 22 is a graph showing the relationship between the toner type created based on this test and the toner charge amount. From this graph, the toner charge amount when negative charge was injected was −2 to −7 [μC / g] in the case of negative charge, and +4 to +38 [μC / g] in the case of positive charge. It can be seen that it is the prototype toner H that is charged the most in any polarity.

Therefore, using the prototype toner H, the relationship between the height and width of the pulse applied to the pulse application electrode 202 and the toner charge amount was determined. The results are shown in FIG. 23 and FIG. FIG. 23 shows the relationship between the applied voltage value (pulse height) and the toner charge amount when the pulse width is fixed at 1.0 [sec]. FIG. 24 shows the relationship between the pulse width and the toner charge amount when the applied voltage value (pulse height) is fixed at −1000 [V]. FIG. 23 shows that in order to inject charges into the prototype toner H, a potential difference of at least 600 [V] or more must be generated between both electrodes regardless of whether the charge is positive or negative. This corresponds to an average electric field strength of 0.6 × 10 ⁶ [V / m] in a gap of 1.0 [mm]. The reason why the toner is charged to +2 to 3 [μC / g] even when the applied voltage value is 0 [V] is as follows. That is, when silica H200 was added to the toner base resin, the toner was used without being sufficiently discharged even though the toner was frictionally charged by high-speed stirring.

  On the other hand, FIG. 24 shows that the charge injection is completed in an extremely short time of 1 [msec] or less. When the pulse width was made shorter than this, the amount of toner flying toward the pulse applying electrode 202 was drastically reduced. However, this is not because charge injection did not occur, but before the flight was completed, the electric field necessary for the flight disappeared. As evidence, when the toner flying with charge was photographed with a high-speed camera and the average flight movement time (interelectrode flight time) was determined, it was about 1 to 2 [msec]. Therefore, instead of setting the pulse height to 0 [V] after 1 [msec], the minimum time required for charge injection is 0 when the charge injection does not occur but the toner flying is reduced to a value that can be continued. It was found to be 2 to 0.3 [msec].

  In the copying machine according to the present embodiment, as a friction promoting material set in the first storage chamber 142 or the second storage chamber 143 as the mixture storage portion in FIG. The user is instructed to use it. This designation can be performed, for example, by shipping the copier or the developing device (100) in a state where a friction promoting material satisfying such requirements is set in the accommodation chamber. Further, for example, a friction promoting material satisfying the above requirements may be shipped by packing it together with the copying machine main body and the developing device (100). Further, for example, the product number or the product name of the friction promoting material that satisfies the above requirements may be specified in the copying machine main body, the developing device (100), and the instruction manuals thereof. Further, for example, the above requirement, product number, product name, etc. may be notified to the user in writing or electronic data.

The reason why the friction promoting substance mainly composed of friction promoting particles made of a non-magnetic material is designated is as follows. That is, in general, non-magnetic materials are easier to granulate than magnetic materials, and can be easily reduced in diameter and sharpened in the particle size distribution, so that it is possible to exert a stable friction charging performance on the friction promoting substance. . It is also possible to reduce the manufacturing cost. As the nonmagnetic material for the friction promoting particles, this copying machine uses glass. However, either organic or inorganic may be applied depending on the charging performance. When a negatively chargeable toner is used, a material such as quartz (SiO ₂ ), glass, polyacrylic resin, polyamide, nylon resin melamine resin, etc. can be applied as a positively charged nonmagnetic material. . In addition, when a positively chargeable toner is used, Teflon (registered trademark) resin, polychlorinated resin, polyethylene resin, or the like can be applied as a negatively chargeable nonmagnetic material. Since these do not require magnetic field control, they can function as a simple and durable carrier material.

In this copying machine, the user is instructed to use, as the friction promoting substance to be set in the accommodation chamber, a material mainly composed of friction promoting particles made of a single material. This designation is performed by the same method as for non-magnetic materials. The reason why such a friction promoting substance is designated is as follows. That is, even if the friction promoting particles are worn over time, the surface material is not changed, so that stable charging performance can be obtained for a long time. As the material, a material having excellent wear resistance, a constant saturation charge amount, and a small charge distribution is desirable. Examples include inorganic materials with high rigidity and excellent charging ability, such as BaTiO ₃ · SiO ₂ , Na ₂ SiO ₃ , B ₂ O ₃ · SiO ₂ , Al ₂ O ₃ , Si ₃ N ₄ , TiO ₂ , ZrO _2. It is done. Moreover, organic materials, such as a polyacryl resin, polyamide, nylon resin melamine resin, may be sufficient. Even if the friction promoting particles are composed of a single material, the specific gravity can be adjusted by adjusting the degree of crystallinity or by providing a fine porosity with a sintered body of aggregates of microcrystals. .

Next, a modified apparatus of the copying machine according to the embodiment will be described.
[First Modification]
FIG. 25 is an enlarged configuration diagram showing the toner replenishing unit 160 of the first modified apparatus together with the second conveying screw 145 of the toner supplying unit. The toner replenishing unit 160 of the first modified apparatus is different from that of the embodiment in the following three points. That is, the first point is that a medium resistance layer made of an insulating material is coated on a solid metal material in the entire surface area of the feeding roller 162. The middle resistance layer has a volume resistivity adjusted to 10 ⁸ to 10 ¹² [Ωcm], and prevents charge injection from the lead-out roller 162 to the toner. The second point is that the feeding power supply circuit 192 applies a feeding bias of −500 [V] not to the middle resistance layer on the surface of the feeding roller 162 but to the metal base therebelow. The third point is that a corona charger 165 is provided as shown. The corona charger 165 causes corona discharge toward the toner filled in the spiral groove 162a of the feeding roller 162 that has passed through the scraping area by the scraping blade 163, and charges the toner to a negative polarity. The toner charging position by the corona charger 165 is a position rotated about 90 ° upstream of the roller rotation from the replenishment region where the feeding roller 162 and the second conveying screw 145 face each other. The toner charged to the negative polarity by the corona charger 165 flies from the spiral groove 162a by a strong electric field due to a potential difference between the metal base of −500 [V] and the grounded second conveying screw 145 in the replenishment region. And adheres to the spiral protrusion 145b of the second conveying screw 145.

  When the toner is actually replenished from the toner replenishment unit 140 onto the second conveying screw 145 of the toner supply unit in the first modified apparatus having such a configuration, the average charge amount Q / M of the toner after replenishment is −5. It was -10 [microC / g]. The toner did not spill from the mesh (146) in the first storage chamber (142).

[Second Modification]
FIG. 26 is an enlarged configuration diagram showing the toner replenishing unit 160 of the second modified apparatus together with the second conveying screw 145 of the toner supplying unit. The toner supply unit 160 of the second modified apparatus is different from that of the first modified apparatus in the following points. That is, instead of the corona charger (165), a carbon nanotube sheet (hereinafter referred to as CNTS) 166 is disposed so as to face the feeding roller 162 with a gap of 0.2 [mm]. It is. As shown in FIG. 27, the CNTS 166 is a sheet-like object in which carbon tubes with a nanometer order of diameter formed by carbon atoms in which carbon atoms are arranged in a hexagonal network are arranged in a matrix. As shown in FIG. 26, a discharge power supply circuit 193 is connected to the CNTS 166, and a discharge bias of −1 [kV] is applied. Then, electron field emission occurs from each carbon nanotube of the CNTS 166, and the toner in the spiral groove 162a of the feeding roller 162 is charged with a negative polarity.

  When the toner is actually replenished from the toner replenishment unit 140 onto the second conveying screw 145 of the toner supply unit in the second modification device having such a configuration, the average charge amount Q / M of the toner after replenishment is −4. It was -8 [microC / g]. The toner did not spill from the mesh (146) in the first storage chamber (142).

[Third Modification Device]
The configuration of the toner replenishing unit (140) of the third modified example device is different from that of the embodiment shown in FIG. 18 in the following three points. That is, the first point is that the feeding roller 162 is a roller in which a medium resistance layer is provided on the surface of a metal core, and a spiral groove is not formed. The second point is that the feeding power supply circuit 192 applies a feeding bias of −500 [V] not to the middle resistance layer on the surface of the feeding roller 162 but to the metal base therebelow. The third point is that a resin regulating blade is provided in place of the urethane rubber scraping blade (163).

  In the third modified apparatus having such a configuration, the toner layer carried on the surface of the feeding roller 162 is replaced with the regulating blade in the same manner as the combination of the developing roller and the regulating blade of the one-component developing device generally used conventionally. When the layer thickness is regulated at the contact position, the toner is triboelectrically charged. When the anti-inventors actually replenished the toner from the toner replenishing unit 140 onto the second conveying screw 145 of the toner supplying unit, the average charge amount Q / M of the toner after replenishment is −6 to −12 [μC / g. ]Met. The toner did not spill from the mesh (146) in the first storage chamber (142).

[Fourth Modification Device]
FIG. 28 is an enlarged configuration diagram showing the toner replenishing unit 160 in the fourth modified example device together with the second conveying screw 145 of the toner supplying unit. The toner replenishing unit 160 in the fourth modified apparatus is different from that of the embodiment in the following two points. That is, the first point is that no scraping blade (163) is provided. The second point is that, as the feeding roller 162, innumerable brushed parts made of conductive fibers (trade name: Thunderron) having a length of 5 mm are spirally formed on the peripheral surface of the metal core 162b. What is used is a spiral brush 162c that is erected. The spiral pitch of the spiral brush 162c composed of countless raised brushes is the same as that of the spiral protrusion 145b of the second conveying screw 145, and the spiral brush 162c and the spiral protrusion 145b always face each other in the replenishment region. When the feeding roller 162 rotates clockwise in the figure, a substantially one layer of toner is formed on the raised end surface of the spiral brush 162c. Then, negative charge is injected into the toner layer from the spiral brush 162c due to the influence of a strong electric field formed in the replenishment region. And it flies from the raising | fluff front-end | tip and adheres to the 2nd conveyance screw 145. FIG.

  When the toner is actually replenished from the toner replenishment unit 140 onto the second conveying screw 145 of the toner supply unit in the fourth modified apparatus having such a configuration, the average charge amount Q / M of the toner after replenishment is −3. It was -8 [microC / g]. The toner did not spill from the mesh (146) in the first storage chamber (142).

[Fifth Modification Device]
FIG. 29 is a schematic configuration diagram showing a fifth modification device. The fifth modified apparatus forms a full-color image with four colors of black (Bk), yellow (Y), cyan (C), and magenta (M), and process units 200Y and M for the respective colors. , C, Bk. Since the process units of the respective colors have almost the same configuration, the following description will be made by omitting the symbols Y, M, C, and Bk as necessary.

  As shown in FIG. 30, the process unit 200 is a unit in which the photosensitive member 11, the drum charger 12, the charge eliminating lamp 23, the cleaning unit 22, and the developing device 100 are unitized, and is attachable to and detachable from the copying machine main body. ing. And it is exchanged when the life is reached.

  In the developing device 100, similarly to the copying machine according to the embodiment, the toner filled in the spiral groove 162a of the feeding roller 162 of the toner replenishing unit 160 is transferred to the second conveying screw 145 of the toner supply unit 140 by charge injection. To be replenished. The supplied toner is transported toward the first storage chamber 142 by the rotational drive of the second transport screw 145 while being taken into the mixture in the second storage chamber 143. Then, after being transferred to the first conveying screw 144 in the first storage chamber 142, it is separated from the mixture by the mesh 146 and supplied to the toner conveying unit 120. The toner transport unit 120 includes a first toner for transporting toner from the toner supply unit 140 side to the photoconductor 11 side, out of the two toner electrostatic transport substrates provided in the copier according to the embodiment. Only the electrostatic transfer substrate 101 is provided. The first toner electrostatic transfer substrate 101 has a rigid portion 101f and a flexible portion 101e. The rigid portion 101f is made of a material having a relatively high rigidity so that the base material is not easily bent, and extends in a substantially horizontal state below the photoconductor 11 so as to face the rigid portion 101f. On the other hand, the flexible part 101e is made of a deformable material for the base material, and is bent downward in the vertical direction from the rigid part 101f and faces the mesh 146 of the toner supply part 140. The toner that has passed through the mesh 146 is supplied to the flexible portion 101e, and then conveyed while being hopped from the lower side to the upper side in the drawing against gravity. Then, after being transferred from the flexible portion 101e to the rigid portion 101f, it is conveyed toward the developing area while hopping in the horizontal direction, thereby contributing to development. The toner conveyed to the collection area without contributing to the development spills from the end of the rigid portion 101 f and then returns along the taper on the bottom surface of the casing of the developing device 100 into the second storage chamber 143.

  In FIG. 29 shown above, the optical writing devices 31Y, 31M, 31C, and Bk are disposed on the left side of the process units 200Y, 200M, and 200B, respectively. The photoconductor is optically scanned. Specifically, a semiconductor laser that emits a laser beam modulated in accordance with image data for each color sent from a scanner device (not shown), an optical deflector such as a collimator lens, a polygon mirror, and an optical system for scanning imaging Etc. are used for optical scanning.

  On the right side of the process units 200Y, 200M, 200C, and 200B, a transfer unit 28 that moves the paper transport belt 25 endlessly is disposed. In the transfer unit 28, the paper transport belt 25 is stretched by a driving roller 26 that is rotationally driven by a driving unit (not shown), a driven roller 27, and four transfer rollers 24 Y, M, C, and Bk. Then, as the driving roller 26 rotates, the paper transport belt 25 is moved endlessly in the clockwise direction in the drawing. The transfer rollers 24Y, 24M, 24C, and 24K form a transfer nip by sandwiching the paper transport belt 25 between the photosensitive members of the process units 200Y, 200M, 200B, and Bk, respectively.

  A sheet feeding cassette 32 that accommodates a bundle of transfer sheets is disposed at the lower part of the copying machine main body, and the uppermost transfer sheet P of the transfer sheet bundle is driven at a predetermined timing by rotating the sheet feeding roller 32a. To the paper feed path. The transferred transfer paper P is supplied to the paper transport belt 25 through the registration roller pair 15. The paper transport belt 25 moves endlessly while holding the supplied transfer paper P on the surface, and sequentially feeds it to the transfer nips for Y, M, C, and Bk. In this process, Y, M, C, and Bk toner images are sequentially superimposed and transferred onto the transfer paper P to form a full color image. The transfer paper P on which the full-color image is formed in this way is transferred from the paper conveying belt 25 to the fixing means 19 of the belt fixing system, and then stacked on the stack section 33 outside the apparatus through the paper discharge roller pair 20. Is done.

  In the fifth variation apparatus having such a configuration, a full color image can be formed by superimposing four color toner images on the transfer paper P by the four process units 200Y, 200M, 200B, and Bk.

[Sixth Modification Device]
FIG. 31 is a schematic configuration diagram showing an image forming unit of the sixth modified example apparatus. The sixth modified apparatus includes a transfer unit 34 that moves the transfer belt 35 endlessly while being elongated in the horizontal direction. In addition, four process cartridges 200Y, 200M, 200C, and 200B are provided in parallel above the transfer unit 34.
Hereinafter, description will be made by omitting the symbols Y, M, C, and Bk as necessary.

  As shown in FIG. 32, the process cartridge 200 is a unit in which the photosensitive member 11, the drum charger 12, the developing device 100, the cleaning means 22, and the like are integrally formed, and is detachable from the copying machine main body. It is configured.

  In the developing device 100, similarly to the copying machine according to the embodiment, the toner filled in the spiral groove 162a of the feeding roller 162 of the toner replenishing unit 160 is transferred to the second conveying screw 145 of the toner supply unit 140 by charge injection. To be replenished. The toner that has been replenished and taken into the mixture sequentially passes through the second storage chamber 143 and the first storage chamber 142, and is then separated from the mixture by the sieving function of the mesh 146 and supplied to the toner transport unit 120. Then, on the surface of the first toner electrostatic transport substrate 101 having the same flexible 101e portion and rigid portion 101f as in the fifth modification apparatus, the toner is transported toward the developing region while hopping by the EH phenomenon, and on the photoreceptor 11. The electrostatic latent image is developed. The toner that has not contributed to the development falls from the end of the first toner electrostatic transport substrate 101 and then returns to the first storage chamber 142 by its own weight along the taper on the bottom surface of the toner transport unit 120.

  In FIG. 31 shown above, the transfer unit 34 stretches the transfer belt 35 by a driving roller 36, a driven roller 37, a secondary transfer backup roller 38, and four transfer rollers 24Y, 24M, 24C, 24K. doing. Then, it is endlessly moved counterclockwise in the figure by a driving roller 36 that is rotationally driven by a driving means (not shown). The four transfer rollers 24Y, 24M, 24C, and 24K form a primary transfer nip with the transfer belt 35 sandwiched between the photosensitive members of the process cartridges 200Y, 200M, 200B, and Bk, respectively. The toner image developed on the photosensitive member of each color process cartridge 200Y, M, C, Bk is superimposed and transferred onto the transfer belt 35 at each primary transfer nip to form a four-color toner image.

  This four-color toner image is transferred onto the transfer paper P that is conveyed at the same timing in the secondary transfer nip where the transfer belt 35 is sandwiched between the secondary transfer backup roller 38 and the secondary transfer roller 39. Batch transfer is performed. A full color image is formed in combination with the white color of the transfer paper P.

  In the sixth modified apparatus having the above configuration, a full color image can be formed by superimposing four color toner images formed by the four process units 200Y, 200M, 200B, and Bk.

[Seventh Modification Device]
FIG. 33 is a schematic configuration diagram showing a seventh modified example device. The seventh modified apparatus includes four sets of process units 401Y, 401Y, M, C, and K for forming each color image of yellow (Y), magenta (M), cyan (C), and black (K). ing. Hereinafter, the subscripts Y, M, C, and K of the respective symbols indicate members for yellow, magenta, cyan, and black, respectively.

  The process units 401Y, 401M, 401C, and 401K include drum-shaped photoconductors 411Y, 411Y, 411Y, and 411K as latent image carriers. In addition to these process units 401Y, M, C, and K, the seventh modified apparatus includes an optical writing unit 407, paper feed cassettes 403 and 404, a registration roller pair 415, a transfer unit 406, and a belt fixing type fixing device 419. , A paper discharge tray 408 is provided. In addition, a manual feed tray and a power supply unit (not shown) are also provided.

  The optical writing unit 407 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of each photoconductor 411Y, M, C, K while scanning with laser light based on image data. .

  Each process unit 401Y, M, C, K has at least a photosensitive member (411Y, M, C, K) as a latent image carrier and a developing device as a developing unit supported on a common support as one unit. It is a thing. And each is comprised so that attachment or detachment with respect to the main body of a 7th modification apparatus is carried out, and it replaces | exchanges when an internal component reaches the lifetime.

  FIG. 34 is an enlarged configuration diagram showing any one of the process units 401Y, 401M, 401C, and K together with a part of the transfer unit 406. The process units 401Y, 401M, 401C, and 401K have substantially the same configuration except that the color of the toner to be used is different. K is omitted. In the figure, a process unit 401 has a photosensitive roller 411 and a brush roller 424 for applying a lubricant to the surface thereof. In addition, a drum cleaning device including a swingable counter blade 422a that performs a cleaning process, a static elimination lamp 423 that performs a static elimination process, and the like are also provided. In addition, a charging unit 412 for uniformly charging the photoconductor 411, a developing device 500, and the like are also provided.

  In the process unit 401, a charging unit 412 having a roller or the like to which an AC charging bias is applied by a power source (not shown) is disposed so as to contact the photoconductor 411. Then, the surface of the photoconductor 411 is uniformly charged while being rotated so that the surface of the contact portion is moved in the same direction as the surface movement of the photoconductor 411 by a driving unit (not shown). When the surface of the photoconductor 411 thus uniformly charged is irradiated with the laser beam modulated and deflected by the optical writing unit (407 in FIG. 33) while being scanned, the surface of the photoconductor 411 is irradiated. An electrostatic latent image is formed. This electrostatic latent image is developed into a toner image by a developing device 500 described later.

  In FIG. 33 shown above, two paper feed cassettes 403 and 404 are disposed at the lower part of the main body casing. These paper feed cassettes 403 and 404 contain transfer paper bundles inside, and feed rollers 403a and 404a are pressed against the uppermost transfer paper P. Then, the paper feeding rollers 403a and 404a are rotated at a predetermined timing to send the transfer paper P to the paper feeding path. A registration roller pair 415 is disposed at the end of the paper feed path, and the transferred transfer paper P is synchronized with the Y toner image formed on the photoreceptor 411Y of the Y process unit 401Y. At the timing to obtain, it sends out toward the transfer unit 406.

  The transfer unit 406 has a transfer conveyance belt 460 that moves in an endless manner while forming four transfer nips in contact with the photoreceptors 411Y, 411Y, M, C, and K, respectively. The transfer conveyance belt 460 is wound around four support rollers 461 so as to form four transfer nips in contact with the photoreceptors 411Y, M, C, and K of the process units 401Y, 401M, 401K. Yes. Among these support rollers 461, the leftmost one in the figure is arranged so that the electrostatic adsorption roller 462 to which a predetermined voltage is applied from a power source (not shown) is opposed. By applying an electric charge from the electrostatic adsorption roller 462, the transfer conveyance belt 460 can electrostatically adsorb the transfer paper P to the front surface (outer surface of the soup).

  Below each transfer nip, transfer bias application rollers 465Y, M, C, and K that are in contact with the back surface of the transfer conveyance belt 460 are provided. The transfer bias application rollers 465Y, M, C, and K are applied with a transfer bias that is constant current controlled by a transfer bias power source (not shown). As a result, a transfer charge is applied to the transfer conveyance belt 460, and a transfer electric field having a predetermined strength is formed between the transfer conveyance belt 460 and the surface of the photosensitive member at each transfer nip. In the seventh modified apparatus, the transfer bias applying roller 465 is provided as the transfer bias applying member, but a brush, a blade, or the like may be provided instead of the roller.

  A one-dot chain line in the figure indicates a transfer paper conveyance path. A transfer sheet (not shown) fed from the paper cassettes 403 and 404 is conveyed by a plurality of conveyance roller pairs while being guided by a conveyance guide (not shown), and is sent to a temporary stop position where a registration roller pair 415 is provided. The transfer paper fed out at a predetermined timing by the registration roller pair 415 is held on the transfer conveyance belt 460, and can contact the photoconductors 411Y, M, C, K. The Y transfer nip, M transfer nip, C transfer nip, Pass sequentially through the K transfer nip. As a result, the Y, M, C, and K toner images developed on the photoreceptors 411Y, M, C, and K of the process units 401Y, 401M, and 401K are superimposed on the transfer paper P at the transfer nip, respectively. The image is transferred onto the transfer paper under the action of the transfer electric field and nip pressure. By this superposition transfer, a full-color image is formed on the transfer paper.

  A transfer sheet (not shown) on which a full-color image is formed is discharged onto a discharge tray 408 after the full-color toner image is fixed in the fixing device 419 having a heating belt.

  In FIG. 34 shown above, the surface of the photoconductor 411 after the toner image is transferred is coated with a predetermined amount of lubricant by the brush roller 424 and then cleaned by the counter blade 422a. Then, it is neutralized by the light emitted from the static elimination lamp 423, and is prepared for the formation of the next electrostatic latent image.

  On the surface of the photoconductor 411 cleaned by the counter blade 422a, a small amount of toner that cannot be completely removed remains. The cleaning residual toner that remains in this manner adheres to the charging unit 412 that rotates while contacting the surface of the photoconductor 411 and becomes dirty. This dirt is removed by roller cleaning.

The developing device 500 includes a cylindrical electrostatic transfer drum 501A as an electrostatic transfer unit, not a plate-shaped electrostatic transfer substrate. The electrostatic transfer drum 501A is manufactured, for example, as follows. That is, first, a conductive layer made of aluminum or the like is deposited on the entire surface of a cylindrical resin base material made of polyimide or the like, and then the conductive layer is transferred to each transport electrode or bus line (common electrode by a photolithography method). In addition, an insulating layer is coated on each patterned electrode or resin base material, and an inorganic material such as SiO ₂ is thinned by a sputtering method as the insulating layer. Or an organic film having a thickness of about 1 to 2 [μm] formed by spin coating, etc., may be pasted on each of the transport electrodes, etc. The electrostatic transport drum 501A having such a configuration is driven by a driving means (not shown). In the seventh modified apparatus, an electrostatic transfer member that can move the surface endlessly is used.However, development is possible. During during rotation of the electrostatic transport drum 501A is stopped.

  FIG. 35 is a perspective view showing the electrostatic transfer drum 501A. In the figure, for the sake of convenience, the illustration of the insulating layer coated on the drum surface is omitted. A plurality of strip-shaped transport electrodes extending in the drum axial direction are provided on the front surface of the electrostatic transport drum 501A so as to be arranged at predetermined intervals over the entire circumference in the circumferential direction. These transport electrodes have a width dimension of 30 [μm] and are arranged with a gap of 30 [μm] from each other. The A transport electrode 501a, the B transport electrode 501b, and the C transport electrode 501c are arranged in this order, and the A phase, B phase, and C phase drive pulse voltages shown in FIG. 3 are output during development.

  FIG. 36 is an enlarged configuration diagram illustrating the developing device 500 of the seventh modified example device together with the photosensitive member 411. Also in this figure, description of subscripts of Y, M, C, and K is omitted. In the drawing, the developing device 500 includes a toner replenishing unit 520, a toner supply unit 540, a cleaning device 560, and the like in addition to the electrostatic conveyance drum 501A. The toner replenishing unit 520 replenishes the toner contained therein into the second housing chamber 543 of the toner supply unit 540 by the rotation of the replenishing roller 526. In the figure, the arrow attached to the periphery of the electrostatic conveyance drum 501A does not indicate the rotation of the electrostatic conveyance drum 501A but indicates the movement of the toner on the drum surface.

  The toner supply unit 540 is disposed not in the direction of gravity of the electrostatic conveyance unit but in the direction of gravity. The toner replenished in the second storage chamber 543 of the toner supply unit 540 is mixed with a mixture of toner and frictionally charged particles and is conveyed by the second conveying screw 545 while being urged to frictionally charge, and then the first. Delivered to the storage chamber 542. When a screw bias is applied to the first transfer screw 544 in the first storage chamber 542 by a power source (not shown), a potential difference is generated between the first transfer screw 544 and the mesh 546 below the first transfer screw 544. Due to this potential difference, the toner in the mixture conveyed in the depth direction in the drawing by the first conveying screw 544 detaches from the surface of the frictionally charged particles in the mixture and flies toward the mesh 546 in the direction of gravity. Then, it passes through the mesh 546 and is supplied to the lower surface of the electrostatic conveyance drum 501A in the drawing. Next, the sheet is conveyed along the curved surface while hopping counterclockwise in the drawing by the EH phenomenon on the curved surface of the electrostatic conveying drum 501A where the driving pulse voltage for development is output to each conveying electrode. At this time, according to the test by the present inventors, the toner was not separated from the drum surface.

  When the toner is conveyed about 280 [deg.] Counterclockwise along the curved surface of the electrostatic conveyance drum 501A in the drawing, the toner reaches the developing area facing the photoconductor 511, where a part of the electrostatic latent image is formed. Contributes to the development of The remaining toner that wanted to contribute to the development passes through the development area.

  A recovery passage having a shape protruding toward the electrostatic conveyance drum 501A is formed at the right end of the toner supply unit 540 in the drawing. The recovery passage is partitioned from the first storage chamber 542, but only the vicinity of the top end on the upper side in the drawing is in communication with the first storage chamber 542. A recovery port that opens toward the electrostatic transfer drum 501A is provided at the lower end of the recovery passage. Further, a collection electrode group 448 in which collection electrodes extending in the depth direction in the drawing are arranged at a predetermined pitch in the passage length direction is provided in the collection passage. A recovery pulse wave, which is a positive polarity DC pulse voltage, is output to each recovery electrode with a phase shift. Excess toner that has passed through the development region while hopping on the electrostatic conveyance drum 501A is electrostatically attracted to the collection electrode group 548 when passing through the position facing the collection port, and the drum surface It moves from the top into the collection passage. Then, under the influence of the recovery pulse wave output to each recovery electrode, it is transported along the recovery path from the lower side to the upper side in the figure, and is recovered in the first storage chamber 542. Thereby, the toner that has not contributed to the development is recycled. As described above, in the seventh modified apparatus, the collection passage and the collection electrode group 548 function as a collection unit that collects excess toner from the surface of the electrostatic conveyance drum 501A serving as the electrostatic conveyance unit.

  A toner concentration detection unit 547 is disposed in the second storage chamber 543 of the toner supply unit 540, detects the toner concentration of the mixture in the second storage chamber 543, and outputs a voltage having a value corresponding thereto. This output voltage value is sent to a control unit (not shown). The control unit includes storage means such as RMA, in which Y Vtref, which is the target value of the output voltage from the toner density detection means, and output voltage from the T sensor mounted in another developing device. Data on Vtref for M, C, and K, which are target values, is stored. Then, for the Y developing device 500, the value of the output voltage from the toner density detecting means 547 is compared with the Y Vtref, and the toner replenishing unit is driven for a time corresponding to the comparison result. By controlling the driving of the toner replenishing portion in this way, an appropriate amount of Y toner is replenished to the mixture in the toner supplying portion 540 whose toner concentration has been reduced as the toner is supplied, and the Y toner concentration falls within a predetermined range. Maintained within. Similar toner replenishment control is performed for the developing devices 500 of other colors.

  Below the electrostatic conveyance drum 501A in the figure, a cleaning device 560 having a cleaning roller 571, a removal blade 572, and the like is disposed so as to be able to contact and separate from the electrostatic conveyance drum 501A. Then, the cleaning roller 571 can be brought into and out of contact with the electrostatic transfer drum 501A by being moved up and down by a moving means such as Solenoiso (not shown). The cleaning roller 571 has a configuration in which a metal core is covered with an elastic material such as rubber or resin, and is driven to rotate clockwise in the figure by driving means (not shown). Further, a cleaning bias having a polarity opposite to that of the toner (positive polarity in this example) is applied from a power source (not shown). During the development period in which the electrostatic transport drum 501A is not rotationally driven, the cleaning roller 571 is retracted from the contact position with the electrostatic transport drum 501A so as not to disturb toner hopping on the drum. Yes.

Next, a description will be given of a comparative apparatus that has adopted an undesirable configuration for the image forming apparatus according to the present invention.
[First Comparative Example Device]
The first comparative example apparatus has substantially the same configuration as the second modification example apparatus shown in FIG. 25, except for the following points. That is, the corona discharge voltage applied to the corona charger 165 is lower than that of the second modification device. When the present inventors actually replenished the toner from the toner replenishing unit 160 onto the second conveying screw 145 of the toner supplying unit using the first comparative example apparatus, the mesh (146) of the first storage chamber (142) was obtained. ) Spilled a large amount of toner under its own weight.

[Second Comparative Example Device]
The second comparative example apparatus has substantially the same configuration as any of the copier, the first modified example apparatus, and the second modified example apparatus according to the first embodiment (hereinafter, substantially the same as the respective configurations). Are referred to as second comparative example device A, second comparative example device B, and second comparative example device C). However, only the following points are different from those devices. That is, the depth of the spiral groove 162a of the feeding roller 162 is 1.0 [mm] which is significantly deeper than 0.2 [mm].

  The present inventors actually applied toner from the toner replenishing unit 160 onto the second conveying screw 145 of the toner supply unit for each of the second comparative example device A, the second comparative example device B, and the second comparative example device C. I tried to replenish. Then, in any of the second comparative examples, the amount of toner flying from within the spiral groove 162a of the feeding roller 162 was reduced, and a large amount of toner remained in the spiral groove 162a after passing through the replenishment area. This is probably because the toner layer in the groove was too thick and the toner was not charged well.

[Third Comparative Example Device]
The third comparative example apparatus has substantially the same configuration as any one of the copying machine, the first modification apparatus, the second modification apparatus, and the fourth modification apparatus according to the first embodiment (hereinafter, each of them). A device having substantially the same configuration is referred to as a third comparative example device A, a third comparative example device B, a third comparative example device C, and a third comparative example device D). However, only the following points are different from those devices. That is, in the replenishment region, the roller and the screw are rotated by shifting the synchronization between the spiral groove 162a or the spiral brush 162c of the feeding roller 162 and the spiral protrusion 145b of the second conveying screw 145 so as not to face each other. It is.

  The inventors actually carry out the second conveyance of the toner supply unit 160 from the toner supply unit 160 for each of the third comparative example device A, the third comparative example device B, the third comparative example device C, and the third comparative example D. The toner was supplied on the screw 145. Then, in any of the third comparative example apparatuses, the amount of toner flying from the feeding roller 162 was reduced to about ¼. As a result of the distance between the toner on the feeding roller 162 and the spiral protrusion 145b of the second conveying screw 145 being too far in the replenishment area, the toner can be separated against the adhesion force to the surface of the feeding roller 162. This is probably because a strong electric field was not formed.

  Next, a second embodiment of a copying machine to which the present invention is applied will be described. The copying machine according to the second embodiment has substantially the same configuration as that of the third modification device described above. However, the following two points are different. That is, the first point is that the above-described regulation blade is not provided. As a result, the toner is not frictionally charged in the toner replenishing section (160). The second point designates toner of a predetermined standard as the toner to be set in the toner storage unit (161) of the toner supply unit (160). This specified standard is one that has been charged by some method prior to shipment from the factory, and then sealed in an insulating encapsulating bag in a nearly vacuum state in order to suppress spontaneous discharge, and has an expiration date for use. It is. Within the expiration date of use, the average charge amount Q / M of the sealed toner is maintained at a value larger on the minus side than −1 [μC / g]. Of course, if the expiration date is exceeded, it may be smaller than −1 [μC / g].

  In this copying machine having such a configuration, as long as the designated toner is used within a predetermined expiration date, the friction promoting particles are satisfactorily contained in the storage chambers (142, 143) of the toner supply unit (140). Adsorb electrostatically. As a result, toner spillage from the mesh (146) can be effectively suppressed. The method for specifying the toner is the same as the method for specifying the friction promoting substance described above.

  For reference, the present inventors conducted the following test. That is, in a two-component development funeral type image forming apparatus in which a two-component developer composed of toner and a magnetic carrier is carried on a developing roll and developed, the toner is charged by stirring the two-component developer in the developing device for a long time. The amount Q / M was saturated with −25 [μC / g]. The solid image was developed on the drum-shaped organic photoreceptor with the toner, and the developed toner was scraped off with a urethane rubber blade and collected. Further, the collected toner was put in a glass container and sealed. After one month of opening, the toner charge amount Q / M was measured and found to be -10 [μC / g]. When this toner is set in the toner accommodating portion (161) of the copying machine according to the second embodiment and toner is supplied, a sufficient amount of toner is supplied from the feeding roller (162) to the second conveying screw (145). Toner flew. The toner did not spill from the mesh (146) of the first storage chamber (142).

  As described above, in the copying machine and the fourth modified apparatus according to the first embodiment, as the charging means provided in the toner replenishing section (160), the one that charges toner particles by charge injection is used. In such a configuration, the toner can be charged satisfactorily without generating ozone unlike the case of using the one charged by corona discharge. Further, unlike the case of using a material that is charged by friction, the toner can be charged well without causing toner deterioration due to friction.

  Further, in the first modified apparatus, as the charging means provided in the toner replenishing section (160), one that charges toner particles by corona discharge is used. In such a configuration, since the toner particles are charged without being rubbed, the stress on the toner can be reduced as compared with the friction charging method. In addition, the charge amount of the toner can be increased as compared with the case of charging by charge injection. Furthermore, the life of the charging means can be extended as compared with the case where the tip is charged by electron field emission from the carbon nanotubes that are gradually consumed with discharge.

  Further, in the second modified apparatus, as the charging means provided in the toner replenishing section (160), one that charges toner particles by electron field emission is used. In such a configuration, since the toner particles are charged without being rubbed, the stress on the toner can be reduced as compared with the friction charging method. In addition, the charge amount of the toner can be increased as compared with the case of charging by charge injection. Furthermore, unlike the corona discharge method, the toner can be charged without generating ozone.

  Further, in the third modified apparatus, as the charging means provided in the toner replenishing portion (160), a device that charges toner particles by friction is used. In such a configuration, the toner can be satisfactorily charged without providing a power source for causing corona discharge, charge injection, or electron field emission.

  Further, in the copying machine and the modified devices according to the first embodiment, the absolute value of the average charge amount Q / M of the toner particles is 1.0 [μC / g as the charging means provided in the toner replenishing unit (160). The above-mentioned charging ability is used. With such a configuration, it is possible to more reliably suppress spillage from the mesh (146) due to toner charging failure.

  Further, in the copier and each modified apparatus according to the first embodiment, as a feeding means provided in the toner replenishing portion (160), the toner is supplied while being held in the toner accommodating portion (161) and is a replenishment destination. A feeding roller (162) serving as a toner carrying member to be replenished to the toner supply unit (140) is used. In addition, as the charging means provided in the toner replenishing section (140), a charging means for charging the toner carried on the feeding roller (162) is used. In such a configuration, among all the toners stored in the toner storage unit (161), only the toner immediately before replenishment is charged, so that toner deterioration due to repeated charging in the toner storage unit (161) can be suppressed. it can.

  Further, in the copying machine according to the second embodiment, the toner set in the toner container (161) is mainly composed of toner particles that are charged in advance prior to factory shipment and whose expiration date is determined. Is specified. In such a configuration, as long as the designated toner is used within the determined expiration date, it is possible to effectively suppress spillage of poorly charged toner from the mesh (146).

  In the copying machine according to the second embodiment, the absolute value of the average charge amount of the toner particles in the toner before the expiration date of use is 1.0 [μC / g] or more. As long as the toner is used within the expiration date, it is possible to more reliably suppress spillage of poorly charged toner from the mesh (146).

  Further, in the copying machine and each modified apparatus according to each embodiment, as the separating means for separating the mixture in the first storage chamber (142) into the toner and the friction promoting substance, the toner and the average particle diameter than this are used. A material that separates a friction promoting substance mainly composed of large friction promoting particles by a mesh (146) is used. In such a configuration, the toner can be easily separated by the sieving function of the mesh (146).

  Further, in the copying machine and each modified apparatus according to each embodiment, spiral protrusions 144b and 145b are provided on the peripheral surfaces of the rotating shafts 144a and 145a as stirring means for stirring the mixture in the respective storage chambers (142 and 143). What stirs while conveying the mixture in the surface direction of the mesh (146) by the rotational drive of the 1st conveyance screw 144 and the 2nd conveyance screw 145 which are formed screw members is used. In such a configuration, the toner and the mixture can be easily separated while conveying the mixture.

  In the copier, the first modified apparatus, or the second modified apparatus according to the first embodiment, a spiral groove is formed on the circumferential surface of a rotatable roller member as a toner carrying member provided in the toner supply unit (140). 162a is used to replenish the toner filled in the groove into the second storage chamber (143), which is a mixture storage section. Furthermore, as the first conveying screw 144 that is a screw member, a screw having the same pitch in the axial direction of the spiral protrusion 144b as the pitch in the axial direction of the groove in the feeding roller 162 that is a toner carrying member is used. In such a configuration, the spiral protrusion 144b and the spiral groove 162a are always opposed to each other at the shortest distance in the replenishment region, so that the toner can be charged satisfactorily without applying an excessive bias.

  Further, in the fourth modified apparatus, a spiral brush 162c in which raised hairs are spirally erected on the peripheral surface of a metal core 162b that is a rotatable rotating shaft is used as the feeding roller 162 that is a toner carrying member. The formed one is used. Furthermore, as the second conveying screw 145 as the screw member, a screw having the same pitch in the axial direction of the spiral protrusion 145a as the pitch in the axial direction of the spiral brush 162c is used. Even in such a configuration, since the spiral projection 144b and the spiral brush 162c are always opposed to each other in the shortest distance in the replenishment region, the toner can be charged satisfactorily without applying an excessive bias.

1 is a schematic configuration diagram showing a copier according to a first embodiment. FIG. 3 is an enlarged configuration diagram illustrating a photoconductor of the copier and a first toner electrostatic transfer substrate of a developing device. FIG. 4 is a waveform diagram showing waveforms of an A-phase driving bias, a B-phase driving bias, and a C-phase driving bias that are applied to a transport electrode of a toner electrostatic transport substrate of the copier. FIG. 2 is an enlarged configuration diagram illustrating a developing device and a photoconductor of the copier. FIG. 3 is a plan sectional view showing a toner supply unit of the developing device. FIG. 3 is a longitudinal sectional view showing the toner supply unit. FIG. 3 is a cross-sectional view showing the toner supply unit. FIG. 6 is a schematic diagram illustrating an electric field formed between a first conveying screw and a mesh of the toner supply unit. (A), (b), (c) is a schematic diagram which shows an example of the mesh formation process for forming the same mesh, respectively. (A), (b) is a schematic diagram which shows an example of the mesh formation process by electrohoming, respectively. (A) is a schematic diagram for demonstrating the magnitude relationship between a toner and the opening of the same mesh, (b) is a schematic diagram for demonstrating the magnitude relationship between a friction charged particle and the same opening. Sectional drawing which shows the same mesh of a double structure, and a mixture. Sectional drawing which shows the same mesh in which each opening was tapered, and a mixture. Sectional drawing which shows the same mesh obtained by coat | covering the surface of the base | substrate which consists of metal materials with an insulating protective film, and a mixture. Sectional drawing which shows the same mesh obtained by coat | covering the metal layer which consists of metal materials on the outer surface of the base | substrate which consists of organic resin materials, and a mixture. Sectional drawing which shows the same mesh obtained by bonding the protective layer which consists of the amount of organic resin agents on the screw opposing surface side in the base material which consists of metal materials, and a mixture. Sectional drawing which shows the same mesh which has the opening formed in the taper shape which spreads toward the exit side from the entrance side into which a toner enters, and a mixture. FIG. 3 is an enlarged configuration diagram illustrating a toner replenishing unit in the copier together with a second conveying screw of the toner supplying unit. FIG. 3 is a perspective view illustrating a part of a feeding roller of the toner supply unit. FIG. 3 is an enlarged configuration diagram illustrating a surrounding configuration of a replenishment area formed between the toner replenishing unit and the toner replenishing unit. Sectional drawing which shows the principal part of the flying apparatus for flying a toner between electrodes. 6 is a graph showing the relationship between toner type and toner charge amount. 6 is a graph showing a relationship between an applied voltage value (pulse height) and a toner charge amount when a pulse width is fixed at 1.0 [sec]. 6 is a graph showing a relationship between a pulse width and a toner charge amount when an applied voltage value (pulse height) is fixed to −1000 [V]. FIG. 10 is an enlarged configuration diagram illustrating a toner replenishing unit of the first modified example device together with a second conveying screw of the toner supplying unit. FIG. 9 is an enlarged configuration diagram illustrating a toner replenishing unit of a second modified example device together with a second conveying screw of a toner supplying unit. The enlarged schematic diagram which shows a carbon nanotube sheet | seat. FIG. 14 is an enlarged configuration diagram illustrating a toner replenishing unit in a fourth modified example device together with a second conveying screw of the toner supplying unit. The schematic block diagram which shows a 5th modification apparatus. The schematic block diagram which shows the process unit of the 5th modification apparatus. The schematic block diagram which shows a 6th modification apparatus. The schematic block diagram which shows the process unit of the 6th modification apparatus. The schematic block diagram which shows a 7th modification apparatus. The expanded block diagram which shows any one of the four process units of the said 7th modification apparatus with a part of transfer unit. The perspective view which shows the electrostatic conveyance drum of the 7th modification apparatus. The expansion block diagram which shows the image development apparatus of the said 7th modification apparatus with a photoreceptor.

Explanation of symbols

11 Photoconductor (latent image carrier)
100 Developing device (developing means)
101 1st toner electrostatic conveyance board (toner electrostatic conveyance member)
140 Toner supply unit (supply means)
142 1st storage chamber (mixture storage part)
143 Second storage chamber (mixture storage section)
144 1st conveyance screw (screw member)
144b Spiral projection 146 Mesh (separation means)
160 Toner replenishment section (replenishment means)
161 Toner container 162 Feed roller (feed means, toner carrying member, part of charging means)
162a Spiral groove 162c Spiral brush (plural brushed)

Claims (18)

In a toner supply device that supplies toner to a toner electrostatic transport means that transports the toner on the surface by electrostatic force,
A mixture containing portion containing a mixture of a triboelectrically charged substance that promotes triboelectric charge for the toner, a stirring means for stirring the mixture in the mixture containing portion, and the mixture stirred by the stirring means Separating means for separating the toner and the friction promoting material, and providing a supply means for supplying the toner separated by the separation means to the electrostatic toner transport means,
A toner containing portion for containing toner for replenishment, a feeding means for feeding toner in the toner containing portion to the supplying means and replenishing the toner, and a toner before being fed into the toner containing portion thereby or in the middle of being fed A toner supply device comprising a replenishing means having a charging means for charging the toner. The toner supply device according to claim 1.
A toner supply device using the charging means for charging the toner particles by charge injection. The toner supply device according to claim 1.
A toner supply device, wherein the charging means is one that charges the toner particles by corona discharge. The toner supply device according to claim 1.
A toner supply device, wherein the charging means is one that charges the toner particles by electron field emission. The toner supply device according to claim 1.
A toner supply device, wherein the charging means is one that charges the toner particles by friction. The toner supply device according to any one of claims 1 to 5,
A toner supply device having a charging ability that makes the absolute value of the average charge amount of toner particles 1.0 [μC / g] or more as the charging means. The toner supply device according to any one of claims 1 to 6,
As the feeding means, a toner carrying member that drives while carrying the toner in the toner accommodating portion and replenishes the replenishment destination is used, and as the charging means, the toner carried on the toner carrying member is charged. A toner supply device using the toner. In a toner supply device that supplies toner to a toner electrostatic transport means that transports the toner on the surface by electrostatic force,
A mixture containing portion containing a mixture of a triboelectrically charged substance that promotes triboelectric charge for the toner, a stirring means for stirring the mixture in the mixture containing portion, and the mixture stirred by the stirring means Separating means for separating the toner and the friction promoting material, and providing a supply means for supplying the toner separated by the separation means to the electrostatic toner transport means,
Providing a replenishing means having a toner accommodating portion for accommodating toner for replenishment, and a feeding means for feeding the toner in the toner accommodating portion to the supplying means;
In addition, a toner supply device, wherein toner charged prior to factory shipment is packed together with a main body. In a toner supply device that supplies toner to a toner electrostatic transport means that transports the toner on the surface by electrostatic force,
A mixture containing portion containing a mixture of a triboelectrically charged substance that promotes triboelectric charge for the toner, a stirring means for stirring the mixture in the mixture containing portion, and the mixture stirred by the stirring means Separating means for separating the toner and the friction promoting material, and providing a supply means for supplying the toner separated by the separation means to the electrostatic toner transport means,
Providing a replenishing means having a toner accommodating portion for accommodating toner for replenishment, and a feeding means for feeding the toner in the toner accommodating portion to the supplying means;
A toner supply device characterized in that, as a toner to be set in the toner storage unit, a toner mainly comprising the toner particles that are charged in advance prior to factory shipment and whose expiration date is determined is designated. The toner supply device according to claim 8 or 9,
A toner supply device, wherein an absolute value of an average charge amount of toner particles in the toner before the expiration date of use reaches 1.0 [μC / g] or more. In a toner conveying apparatus comprising: a toner electrostatic conveying means that conveys toner on a surface by electrostatic force; and a toner supply means that supplies toner to the toner electrostatic conveying means.
11. A toner conveying apparatus using the toner supplying apparatus according to claim 1 as the toner supplying means. The toner conveying device according to claim 11.
A toner conveying device, wherein as the separating means, a toner and a material that separates the friction-promoting substance mainly composed of friction-promoting particles having an average particle diameter larger than the toner are separated by a mesh. The toner conveying device according to claim 12.
Toner transporting means, wherein the stirring means is a means for stirring the mixture while transporting the mixture in the surface direction of the mesh by rotationally driving a screw member having a spiral projection formed on the peripheral surface of the rotating shaft. apparatus. The toner conveying device according to claim 13.
The toner supply device according to claim 7 is used.
As the toner carrying member, a member in which a spiral groove is formed on the peripheral surface of the rotatable roller member, and the toner filled in the groove is replenished into the mixture container,
A toner conveying device using the screw member having the same pitch in the axial direction of the spiral projection as the pitch in the axial direction of the groove in the toner carrying member. The toner conveying device according to claim 13.
The toner supply device according to claim 7 is used.
As the toner carrying member, a brushed brush is erected on the peripheral surface of the rotatable rotating shaft,
A toner conveying device using the screw member having the same pitch in the axial direction of the spiral projection as the pitch in the axial direction of the spiral raising of the toner carrying member. The latent image carried on the latent image carrier is conveyed to a position facing the latent image carrier while the toner existing on the surface of the electrostatic toner carrier provided on the toner carrier is moved by electrostatic force. In the developing device that contributes to the development of
A developing device using the toner conveying device according to claim 11 as the toner conveying means. In a process unit in which at least a latent image carrier that carries a latent image in the image forming apparatus and a developing unit that develops the latent image on the latent image carrier are supported as a single unit on a common support. ,
A process unit using the developing device according to claim 16 as the developing means. In an image forming apparatus comprising: a latent image carrier that carries a latent image; and a developing unit that develops the latent image on the latent image carrier.
An image forming apparatus using the developing device according to claim 16 as the developing means.

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