Electrostatic collection device

Abstract

To provide an electrostatic collection device capable of efficiently eliminating the static electricity from a cleaning target that has been electrified due to rubbing by a collection member.SOLUTION: An electrostatic collection device 100 includes: a collection rotating body 11 that rotates and rubs a cleaning target F with a collection member 11a at a collection part P1 to collect a collection object H from the cleaning target F which moves relative to the collection part P1 onto the collection member 11a; and removal members 12, 13 that remove the collection object H from the collection member 11a. The electrostatic collection device also includes a static elimination member 15a which is arranged so as to face the cleaning target F on the downstream side relative to the collection part P1 in a relative movement direction E of the cleaning target F with respect to the collection part P1. The static elimination member 15a is electrically connected to conductors 11a, 12b, 13b which constitute at least a portion of at least one of the collection rotating body 11 or the removal members 12, 13, and does not contact the cleaning target F.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electrostatic collector that collects matter from a cleaning target. [Background technology]

[0002] Conventionally, techniques have been proposed for capturing fine particles using electrostatic adhesion in various manufacturing equipment, industrial products, household vacuum cleaners, etc. The "fine particles" referred to here refer to, for example, toner and paper dust in electrophotographic image forming devices, and dust in manufacturing equipment and homes.

[0003] For example, Patent Document 1 discloses an electrostatic collector (cleaning device) that uses electrostatic adhesion to collect toner on the surface of an electrostatic latent image carrier in an electrophotographic image forming apparatus. Patent Document 2 discloses an electrostatic collector (cleaning device) that uses electrostatic adhesion to collect dust on the surfaces of glass substrates, printed circuit boards (PCB, PCBA, etc.), films, sheets, plastic plates, etc. Patent Document 3 discloses an electrostatic collector (electrostatic vacuum cleaner) that uses electrostatic adhesion to collect dust on the floor surface.

[0004] In these electrostatic collection devices, the materials to be collected on the cleaning target are first rubbed against the collection rotor by a collection rotor, and the materials electrostatically attached to the collection rotor are then collected by a recovery rotor or the like. As the collection rotor, a brush roller having a core with raised fibers constituting the collection member is used. As the recovery rotor, a recovery roller having a surface layer constituting the recovery member is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 1-6989 [Patent Document 2] Patent No. 4886097 [Patent Document 3] JP 2015-84993 A Summary of the Invention [Problem to be solved by the invention]

[0006] In such an electrostatic collector, if the electrostatic adhesion of the collection member (such as raised fibers) is increased to improve the collection performance of the collection rotor, the object to be cleaned may become charged if the object to be cleaned has high electrical resistance. If the object to be cleaned is charged, for example, when the electrostatic collector is used as a manufacturing facility or a household cleaning device, a problem may occur in which dust and the like re-adhere to the object to be cleaned. Furthermore, if the object to be cleaned is charged, for example, when the electrostatic collector is used in an electrophotographic image forming apparatus, it may cause image defects.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an electrostatic collector capable of efficiently removing static electricity from a cleaning target that has been charged by being rubbed by a collecting member. [Means for solving the problem]

[0008] The above object is achieved by the electrostatic collection device according to the present invention. In summary, the present invention is an electrostatic collection device comprising a rotatable collection rotor having a collection member made of an insulator that comes into contact with a cleaning target to form a collection section, the collection rotor rotating to cause the collection member to rub against the cleaning target in the collection section, thereby collecting objects to be collected from the cleaning target that moves relative to the collection section, and a removal member that removes the objects to be collected from the collection member, the electrostatic collection device comprising a static elimination member disposed so as to face the cleaning target downstream of the collection section in the relative movement direction of the cleaning target with respect to the collection section, the static elimination member being electrically connected to a conductor that does not come into contact with the cleaning target and that constitutes at least a part of at least one of the collection rotor or the removal member. Effect of the Invention

[0009] According to the present invention, it is possible to efficiently remove electricity from a cleaning target that has been rubbed by a collection member and has become charged. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic external perspective view of a cleaning device according to a first embodiment. [Diagram 2] 1 is a schematic cross-sectional view of a cleaning device according to a first embodiment. [Diagram 3] FIG. 2 is a schematic diagram for explaining a method for measuring a potential decay rate. [Figure 4] FIG. 11 is a graph for explaining a potential attenuation rate. [Diagram 5] 2 is a schematic side view of a portion of the static eliminator according to the first embodiment. FIG. [Figure 6] FIG. 11 is a schematic cross-sectional view of a cleaning device according to Comparative Example 2. [Figure 7] FIG. 11 is a schematic cross-sectional view of an image forming apparatus equipped with a paper powder collecting device according to a second embodiment. [Figure 8] FIG. 11 is a schematic cross-sectional view of a paper powder collecting device according to a second embodiment. [Figure 9] FIG. 11 is a schematic cross-sectional view of a paper powder collecting device according to Comparative Example 4. [Figure 10] FIG. 11 is a schematic cross-sectional view of a paper powder collecting device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The electrostatic collector according to the present invention will now be described in more detail with reference to the drawings.

[0012] [Example 1] In this embodiment, the electrostatic collection device according to the present invention is used as a cleaning device (vacuum cleaner, manual vacuum cleaner) for cleaning a floor surface.

[0013] (1) Overall configuration of the cleaning device 1 is a schematic perspective view of the exterior of a cleaning device 100 according to this embodiment. In this embodiment, the cleaning target of the cleaning device 100 is mainly a floor surface (particularly a carpet) F, and the objects to be collected are dust particles and the like (hereinafter simply referred to as "dust particles") H (FIG. 2) present on the floor surface F.

[0014] The cleaning device 100 has a device body 101 and a handle 102 connected to the device body 101. A user can hold the handle 101 and clean the floor surface F while pushing the device body 101 placed on the floor surface F in the direction of the arrow D in the figure. The cleaning device 100 can also clean the floor surface F when pulling back the device body 101 in the opposite direction to the direction of the arrow D in the figure. However, in this embodiment, it is assumed that the floor surface F is cleaned while the device body 101 is mainly pushed in the direction of the arrow D in the figure, and the attachment position and movable range of the handle 102 relative to the device body 101 are set. Here, the direction of the arrow D in the figure is also referred to as the "cleaning direction D". In addition, the relative movement direction of the floor surface F with respect to the device body 101 when the device body 101 moves in the cleaning direction D, that is, the opposite direction to the cleaning direction D (the direction of the arrow E in the figure), is also referred to as the "cleaning target movement direction E". At the front of the housing 106 of the device body 101 in the cleaning direction D, an opening 103 for taking in dust H into the housing 106 is provided.

[0015] 2 is a schematic cross-sectional view of the cleaning device 100 of this embodiment (showing a cross-section substantially perpendicular to the direction of the rotation axis of the brush roller 11 described later). The device body 101 of the cleaning device 100 has the brush roller 11 which is a collecting rotor, the collection roller 12 which is a first removing member (collection rotor), the cleaning blade 13 which is a second removing member (scraping member), a storage container (storage section) 14, a charge removing section 15, a motor 104 which is a driving source constituting the driving means, a battery 105 which supplies power to the motor etc., and a housing 106 which houses these inside.

[0016] The device body 101 is provided with a brush roller 11 so as to be exposed to the outside of the housing 106 through an opening 103 provided in the housing 106. The brush roller 11 constitutes a collecting means that collects the dust H adhering to the floor surface F by rotating while rubbing against the floor surface F on which the dust H is attached. The floor surface F may be, for example, a carpet, and the dust H may be embedded in the carpet fibers. The brush roller 11, by rotating, sweeps the dust H on the floor surface F into the inside of the housing 106 through the opening 103 provided in the housing 106. The device body 101 is also provided with a collection roller 12 and a cleaning blade 13 on the downstream side of the brush roller 11 in the cleaning target movement direction E (behind the brush roller 11). The collection roller 12 and the cleaning blade 13 constitute a removing means that removes the dust H adhering to the brush roller 11 from the brush roller 11. A storage container 14 is provided downstream of the collection roller 12 and cleaning blade 13 in the cleaning object movement direction E (behind the collection roller 12 and cleaning blade 13). The storage container 14 stores dust H collected from the brush roller 11 by the collection roller 12 and cleaning blade 13. A charge removing unit 15 is provided downstream of the storage container 14 in the cleaning object movement direction E (behind the storage container 14). The charge removing unit 15 constitutes a charge removing means for removing charge from the floor surface F that has been rubbed by the brush roller 11. A motor 104 and a battery 105 for supplying power to the motor 104 and the like are provided downstream of the charge removing unit 15 in the cleaning object movement direction E (behind the charge removing unit 15). In this embodiment, the housing 106 is configured by connecting a first housing 106a and a second housing 106b, and the brush roller 11, the collection roller 12, the cleaning blade 13, and the storage container 14 are disposed inside the first housing 106a. The static electricity removing unit 15, the motor 104, and the battery 105 are disposed inside the second housing 106b. The internal space of the first housing 106a and the internal space of the second housing 106b are partitioned by a wall 106c that constitutes the housing 106 (at least one of the first housing 106a and the second housing 106b).

[0017] A brief description will now be given of the cleaning operation of the cleaning device 100. As the user pushes the device body 201 in the cleaning direction D while the brush roller 11 rotates, dust H on the floor surface F is rubbed by the brush roller 11 and collected by the brush roller 11 due to electrostatic adhesion (electrostatic attraction). The dust H collected by the brush roller 11 is collected by electrostatic adhesion onto the collection roller 12, which rotates while in contact with the brush roller 11. The dust H collected by the collection roller 12 is scraped off the collection roller 12 by the cleaning blade 13 and stored in the storage container 14. Details of each component will be described later.

[0018] (2) Brush roller Next, the brush roller 11 as the collecting means will be further described.

[0019] The brush roller 11 has bristles 11a as a collection member that contacts and rubs against the floor surface F, and a core (core metal) 11b as a support that supports the bristles 11a. The core 11b of the brush roller 11 is made of a cylindrical member and is disposed facing the floor surface F such that the rotation axis direction of the core 11b is substantially parallel to the floor surface F and intersects (typically substantially perpendicular) with the cleaning direction D when the device body 101 is placed on the floor surface F. The core 11b of the brush roller 11 is rotatably supported by the housing 106 (first housing 106a) of the cleaning device 100 via rotating shafts (not shown) provided at both ends in the direction of the rotation axis. The elastically deformable bristles 11a of the brush roller 11 are provided on the outer circumferential surface of the core 11b of the brush roller 11. The bristles 11a of the brush roller 11 are provided substantially uniformly on the outer circumferential surface of the core 11b of the brush roller 11 in substantially the entire area (for example, about 200 to 300 mm) in the rotation axis direction of the core 11b. In this embodiment, the brush roller 11 is configured by directly implanting the bristles 11a on the outer circumferential surface of the core 11b. However, the method of implanting the bristles 11a on the core 11b of the brush roller 11 is not particularly limited, and any available method can be used. For example, the brush roller 11 may be configured by wrapping and fixing a base fabric (not shown) provided with the bristles 11a on the outer circumferential surface of the core 11b. As the base fabric, a woven fabric formed of the same or different fibers as the bristles 11a can be used.

[0020] In this embodiment, the core 11b of the brush roller 11 is made of aluminum, which is a conductive metal material serving as a conductor (conductive material). In FIG. 2, the conductor parts are shaded (the same applies to other figures). The bristles 11a of the brush roller 11 are made of an insulating resin material serving as an insulator (electrically insulating material). That is, the surface of the core 11b made of a conductor is covered with the bristles 11a made of an insulator. In this embodiment, the free length (pile length) of the bristles 11a of the brush roller 11 is 11 mm, the outer diameter of the core 11b of the brush roller 11 is 18 mm, and the diameter (outer diameter) of the brush roller 11 is 40 mm. The natural length of the bristles 11a of the brush roller 11 is the length when the bristles 11a are not deformed by pressure applied by the floor surface F or the collection roller 12. The diameter of the brush roller 11 is the diameter of the circumscribed circle of the bristles 11a in the natural length state. From the viewpoint of collection performance, the thickness of the bristles 11a of the brush roller 11 is preferably 10 denier or more. On the other hand, from the viewpoint of preventing an excessive increase in the rotation torque of the brush roller 11, the thickness of the bristles 11a of the brush roller 11 is preferably 125 denier or less. Similarly, from the viewpoint of collection performance, the density of the bristles 11a of the brush roller 11 is preferably 15 kF / inch 2 On the other hand, the density of the naps 11a of the brush roller 11 is set to 60 kF / inch from the viewpoint of preventing the rotation torque of the brush roller 11 from increasing too much. 2 In other words, the nap 11a of the brush roller 11 preferably has a thickness of 10 denier or more and 125 denier or less, and a density of 15 kF / inch 2 More than 60kF / inch 2 It is preferable that:

[0021] The distance between the core 11b of the brush roller 11 and the floor surface F is regulated by the bottom surface of the housing 106 and is set to a value (for example, 10 mm) smaller than the natural length of the bristles 11a of the brush roller 11. That is, in this embodiment, the distance between the surface formed by the bottom surface of the housing 106 placed on the floor surface F and the core 11b of the brush roller 11 is set to a value smaller than the natural length of the bristles 11a of the brush roller 11. Note that the housing 106 may be provided with a member such as wheels that is placed on the floor surface F. In that case, it is sufficient that the distance between the surface formed by the contact portion of the wheels or the like with the floor surface F and the core 11b of the brush roller 11 is set to a value smaller than the natural length of the bristles 11a of the brush roller 11. Therefore, the brush roller 11 rotates while the bristles 11a are in contact with the floor surface F. The brush roller 11 receives driving force from the motor 104 via a drive transmission member (not shown) and rotates in the direction of the arrow in the figure (clockwise direction) at a peripheral speed (surface movement speed) of 140 mm / sec. That is, the brush roller 11 rotates such that the movement direction of the bristles 11a is opposite to the movement direction E of the cleaning target at a contact portion (collection portion) P1 between the bristles 11a and the floor surface F. As the brush roller 11 rotates, the bristles 11a of the brush roller 11 move in a circular motion. As the brush roller 11 rotates, the bristles 11a in contact with the floor surface F rub the floor surface F with the bristles 11a, rubbing the floor surface F and the dust H on the floor surface F, thereby collecting the dust H from the floor surface F.

[0022] The rotation direction and circumferential speed of the brush roller 11 are not limited to those of this embodiment. The brush roller 11 may rotate so that the moving direction of the bristles 11a and the moving direction E of the cleaning target are the same at the contact portion (collection portion) P1 between the bristles 11a and the floor surface F. The circumferential speed of the brush roller 11 may be faster or slower than those of this embodiment.

[0023] Here, an insulator is one with a volume resistivity of 10 8 (Ω·m) or more, preferably 10 10 (Ω·m) or higher. Typically, however, an insulator has a volume resistivity of 10 16 (Ω·m) or less. A conductor is one with a volume resistivity of 10-6 (Ω·m) or less, typically 10 -8 (Ω·m). Semiconductors are materials whose volume resistivity is between that of insulators and conductors.

[0024] Furthermore, for the sake of convenience, the magnitude (high / low) of a potential (or a potential difference) refers to the magnitude (high / low) when compared in absolute value, unless otherwise specified.

[0025] When two materials at different positions in the triboelectric series are rubbed against each other, charges are exchanged between the two materials, and one of them is positively charged and the other negatively charged. The triboelectric series is a sequence of these pluses and minuses, and generally, the farther the positions in the triboelectric series, the stronger the charge tends to be. Generally, dust H is mostly on the positive side of the triboelectric series, such as various fibers such as cotton dust generated from clothing, human dandruff and sebum, and mite droppings and carcasses. The same is true for paper dust described in Examples 2 and 3. It is desirable to use a material for the raised bristles 11a of the brush roller 11 that is as far away as possible on the negative side of the position in the triboelectric series from the dust H and is more positive than the material (PFA in this example) of the surface layer 12a of the recovery roller 12 described later. Therefore, in this example, the raised bristles 11a of the brush roller 11 are made of PET fibers, which are fibers made of PET (polyethylene terephthalate). When the bristles 11a of the rotating brush roller 11 rub against the dust H on the floor surface F, the bristles 11a of the brush roller 11 are negatively charged and the dust H is positively charged. As a result, the potential of the bristles 11a of the brush roller 11 becomes more negative compared to the floor surface F, and the dust H can be collected from the floor surface F. In this embodiment, the volume resistivity of the material of the bristles 11a of the brush roller 11 is 10 13 Ω cm or more, 10 18 Ω·cm or less.

[0026] Since the brush roller has the function of collecting dust H as described above, it is preferable that the bristles 11a of the brush roller have a surface potential decay rate R1 (herein also referred to as "potential decay rate R1") of 10% or less during one rotation of the brush roller 11. The potential decay rate R1 may be 0%. If the potential decay rate R1 is greater than 10%, it becomes difficult to retain the dust H collected by the bristles 11a while the brush roller 11 is rotating, and the dust H may be scattered around the brush roller 11. Below, a method for measuring the potential decay rate R1 and the potential decay time constant will be described.

[0027] Fig. 3 is a schematic diagram for explaining a method for measuring the potential decay rate R1 and the potential decay time constant. First, as shown in Fig. 3(a), the cleaning device 100 is placed with the opening 103 facing upward with the collection roller 12 removed. The brush roller 11 is rotated in the direction of the arrow in the figure (clockwise direction) at a peripheral speed of 140 mm / sec, and the potential of the surface (outer peripheral surface) of the bristles 11a of the brush roller 11 is measured with a surface potential meter 31 (product name: MODEL P0865, manufactured by Trek Japan Co., Ltd.). The rubbing member 32 is applied to the bristles 11a of the brush roller 11 with a pressure of 0.01 g / cm 2 The rubbing member 32 is pressed in the direction of the arrow in the figure (from top to bottom) for 5 seconds with a pressure of 1000 psi. The rubbing member 32 is preferably made of a material whose position in the triboelectric series is as far away as possible on the negative side from PET, and is a brush-like member with a high contact rate with the raised fibers 11a. Here, a brush (pile length 6 mm, thickness 3 denier, density 15 to 60 kF / inch) with raised fibers of nylon N6, an insulating resin material, is used. 2 After pressing the rubbing member 32 against the bristles 11a of the brush roller 11, as shown in Fig. 3(b), the rubbing member 32 was moved away in the direction of the arrow in the figure (from the bottom to the top), and the time transition of the surface potential of the bristles 11a of the brush roller 11 was measured.

[0028] FIG. 4 shows the time transition of the surface potential of the raised hairs 11a of the brush roller 11. During the first 5 seconds (area (time period) A in FIG. 4), the rubbing member 32 is pressed against the raised hairs 11a of the brush roller 11, so the surface potential of the raised hairs 11a rises, and the surface potential (initial potential) of the raised hairs 11a rises to V0 = -7.6 kV. When the rubbing member 32 is separated from and retracted from the raised hairs 11a of the brush roller 11, the surface potential of the raised hairs 11a starts to drop. The potential decay time constant τ is obtained from the drop curve of the surface potential of the raised hairs 11a. The potential decay time constant τ is defined as the time required for the surface potential (residual potential) to decay to V0 × (1 / e) when the surface is charged to an initial potential V0, and is an index of how easily the charged potential can be maintained. Here, e is the base of the natural logarithm. When the surface potential of the raised bristles 11a of the brush roller 11 decays from V0 when the rubbing member 32 is separated and retracted (area B (time period) in FIG. 4), it takes 12.5 seconds for the potential to decay to V0×(1 / e)=−2.8 kV, so the potential decay time constant τ is 12.5 seconds. The surface potential V of the raised bristles 11a of the brush roller 11 in area B in FIG. 4 (also referred to as the “potential decay period”) B can be approximated by the following formula: V B (t) = V0 × exp(-t / τ) (1)

[0029] In the above formula (1), t is the elapsed time (sec) in the potential decay period, V0 is the initial potential (potential at t=5 seconds) (V), and τ is the potential decay time constant (sec).

[0030] The potential attenuation rate R1 after one rotation of the brush roller 11 is expressed by the following formula (2). R1=1-V B (t1) / V0=1-exp(-t1 / τ) t1=πd / s (2)

[0031] In the above formula (2), t1 is the time (sec) required for the brush roller 11 to complete one rotation, π is the circular constant, d is the diameter (mm) of the brush roller 11, s is the peripheral speed (surface movement speed) (mm / sec) of the brush roller 11, and τ is the potential decay time constant (sec).

[0032] As described above, it is preferable that the potential decay rate R1 is 10% or less. In the configuration of this embodiment, the diameter of the brush roller 11 is 40 mm, and the peripheral speed is 140 mm / sec, so the time t1 required for the brush roller 11 to make one revolution is 0.90 sec. When the brushed fibers 11a with a potential decay time constant τ=12.5 sec are used, the potential decay rate R1 is 6.9% after t1=0.90 sec from the formula (1). Thus, the potential decay rate R1 of the brush roller 11 of this embodiment is 10% or less. Table 1 summarizes the measurement results and calculation results regarding the potential decay rate R1 and the potential decay time constant τ of the brush roller 11 of this embodiment.

[0033] [Table 1]

[0034] (3) Removal means Next, the collection roller 12 and cleaning blade 13 as removing means will be further described.

[0035] The collection roller 12, which is a first removal member (collection rotor), has a surface layer 12a as a collection member that collects dust H from the bristles 11a of the brush roller 11, and a base (core metal) 12b on whose outer periphery the surface layer 12a is provided. The base 12b of the collection roller 12 is made of a cylindrical member and is disposed facing the brush roller 11 so that the rotation axis direction of the base 12b and the rotation axis direction of the brush roller 11 are substantially parallel. The collection roller 12 is rotatably supported by the housing 106 (first housing 106a) via a rotating shaft portion (not shown) provided at both ends in the rotation axis direction. The length of the collection roller 12 in the rotation axis direction is equal to the length of the range (area) in which the bristles 11a are provided in the rotation axis direction of the brush roller 11. In this embodiment, the base 12b of the collection roller 12 is formed of aluminum, which is a conductive metal material serving as a conductor. Moreover, the surface layer 12a of the recovery roller 12 is formed of an insulating resin material as an insulator. That is, the recovery roller 12 is configured such that the surface of the base portion 12b formed of a conductor is covered with the surface layer 12a formed of an insulator. In this embodiment, the thickness of the surface layer 12a of the recovery roller 12 is 0.5 mm, the diameter of the base portion 12b of the recovery roller 12 is 24 mm, and the outer diameter of the recovery roller 12 is 25 mm. The distance between the core portion 11b of the brush roller 11 and the recovery roller 12 is set to a value (for example, 7 mm) smaller than the natural length of the bristles 11a of the brush roller 11. Therefore, the recovery roller 12 rotates while contacting the bristles 11a of the brush roller 11. That is, the brush roller 11 rotates while the bristles 11a are deformed into the floor surface F and the recovery roller 12, respectively. The drive force from the motor 104 is transmitted to the collection roller 12 by a drive transmission member (not shown), and the collection roller 12 rotates in the direction of the arrow in the figure (counterclockwise direction) at a peripheral speed (surface movement speed) of 140 mm / sec. In other words, the collection roller 12 rotates such that the movement direction of the bristles 11a of the brush roller 11 and the movement direction of the surface of the collection roller 12 are forward directions at a contact portion (collection portion) P2 between the bristles 11a of the brush roller 11 and the collection roller 12. As the collection roller 12 rotates, the surface layer 12a of the collection roller 12 moves in a circular motion.

[0036] The rotation direction and circumferential speed of the collection roller 12 are not limited to those in this embodiment. The collection roller 12 may rotate so that the movement direction of the bristles 11a of the brush roller 11 is opposite to the movement direction of the surface of the collection roller 12 at the contact portion (collection portion) P2 between the bristles 11a of the brush roller 11 and the collection roller 12. The circumferential speed of the collection roller 12 may be faster or slower than those in this embodiment.

[0037] The material of the surface layer 12a of the collection roller 12 is a material whose position in the triboelectric series is more negative than the material of the bristles 11a of the brush roller 11 (PET in this embodiment) with respect to the dust H. In this embodiment, the surface layer 12a of the collection roller 12 is formed of PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), a type of fluororesin. Therefore, the surface layer 12a of the collection roller 12 is charged to the opposite polarity (negative) to the dust H due to friction between the bristles 11a of the brush roller 11 and the dust H. At this time, the surface layer 12a of the collection roller 12 is charged so that the charge amount per unit area is larger than that of the bristles 11a of the brush roller 11. As a result, the surface layer 12a of the collection roller 12 can adsorb the dust H from the surface of the bristles 11a of the brush roller 11. Dust H adhering to the surface layer 12a of the collection roller 12 is scraped off by the cleaning blade 13 and stored in a storage container 14 provided in the housing 106 (first housing 106a).

[0038] In this embodiment, the cleaning blade 13, which is a second removing member (scraping member), is configured to have a cleaning blade support portion (supporting metal plate) 13b and a cleaning blade rubber portion 13a. The cleaning blade support portion 13b is formed of a plated steel plate, which is a conductive metal material as a conductor. The cleaning blade rubber portion 13a is formed of polyurethane (urethane rubber), which is a rubber material as an elastic body (elastic material) having appropriate elasticity and hardness. The cleaning blade 13 is attached to the housing 106 (first housing 106a) by fixing the cleaning blade rubber portion 13a to the cleaning blade support portion 13b, which is fixed to the housing 106. The cleaning blade rubber portion 13a is a plate-like member that is approximately rectangular in plan view and has a predetermined length in the longitudinal direction disposed approximately parallel to the rotation axis direction of the collection roller 12 and in the lateral direction perpendicular to the longitudinal direction, and has a predetermined thickness. The length of the cleaning blade rubber part 13a in the longitudinal direction is equal to the length of the collection roller 12 in the longitudinal direction. The cleaning blade rubber part 13a has a free end, which is one end in the lateral direction, located upstream in the moving direction of the surface of the collection roller 12 from the fixed end, which is the other end, such that the free end is brought into contact with the surface of the collection roller 12. In other words, the cleaning blade 13 is brought into contact with the surface of the collection roller 12 in a counter direction to the rotation direction of the collection roller 12. Dust H scraped off from the surface of the rotating collection roller 12 by the cleaning blade 13 is stored in a storage container 14 provided in the housing 106 (first housing 106a).

[0039] In this manner, the dust H is removed from the brush roller 11 by the collection roller 12 and cleaning blade 13 which constitute the removing means.

[0040] The removal member for removing the dust H from the collection roller 12 is not limited to a blade-shaped member, but may be, for example, a pad-shaped member, a sheet-shaped member, a brush-shaped member, or the like.

[0041] (4) Static elimination means Next, the charge removing section 15 as the charge removing means will be further described.

[0042] The static eliminator 15 is disposed at a position downstream of the brush roller 11 (and further the collection roller 12, cleaning blade 13, and storage container 14 in this embodiment) in the measurement object movement direction E. That is, the static eliminator 15 is disposed at a position downstream of the collection unit P1 in the measurement object movement direction E. The static eliminator 15 is attached to the housing 106 (second housing 106b) such that a static eliminator cloth 15a, which will be described later, is exposed to the outside of the housing 106 (second housing 106b) from a static elimination opening 106d provided in the bottom surface of the housing 106 (second housing 106b) and faces the floor surface F.

[0043] The static elimination unit 15 is configured to have a static elimination cloth 15a as a static elimination member and a static elimination cloth support part 15b that supports the static elimination cloth 15a. The static elimination cloth 15a is supported by being sandwiched by the static elimination cloth support part 15b, and the static elimination cloth support part 15b is fixed to the housing 106 (second housing 106b) to be attached to the housing 106 (second housing 106b). The static elimination cloth support part 15b is made of ABS resin (acrylonitrile butadiene styrene resin), which is an insulating resin material as an insulator. The static elimination member is made of a conductor or a semiconductor. In this embodiment, the static elimination cloth 15a as a static elimination member is made of a nonwoven sheet made of conductor or semiconductor fibers. Particularly, in this embodiment, the static electricity removing cloth 15a is formed of a sheet having a thickness of 0.1 mm, which is made of an aggregate (nonwoven fabric) of fine acrylonitrile-copper sulfide composite fibers, which are fibers made of metal threads, assembled in a felt-like shape. FIG. 5 is a schematic side view of a part of the static electricity removing cloth 15a seen along the cleaning direction D (or the moving direction E of the cleaning object). The static electricity removing cloth 15a is arranged in a direction intersecting (typically substantially perpendicular to) the cleaning direction D (or the moving direction E of the cleaning object), that is, in a direction substantially parallel to the rotation axis direction of the brush roller 11. In this embodiment, the longitudinal length of the static electricity removing cloth 15a is equal to the longitudinal length of the brush roller 11. It is preferable that the longitudinal length of the static electricity removing cloth 15a is longer than the longitudinal length of the region where the naps 11a of the brush roller 11 are provided (and further the surface layer 12a of the collection roller 12). In other words, in the longitudinal direction of the neutralizing cloth 15a, it is preferable that the area where the naps 11a of the brush roller 11 are provided (and further the surface layer 12a of the collection roller 12) is contained inside the neutralizing cloth 15a. This makes it possible to effectively neutralize the floor surface F that has been charged by the brush roller 11.

[0044] The fibers constituting the static neutralizing cloth 15a of this embodiment are extremely fine, with each fiber having a diameter of 15.6 to 19 μm, and a volume resistivity of 5.85×10 -2Its electrical resistance is about Ω·cm, making it a semiconductor close to a conductor. Therefore, this fiber has excellent corona discharge properties. When a strong electric field is induced in the acrylonitrile-copper sulfide composite fiber, the air around the fiber is ionized, and a polarity shift occurs in the acrylonitrile-copper sulfide composite fiber. This phenomenon causes the accumulated negative charge to be released into the atmosphere from the tip of the acrylonitrile-copper sulfide composite fiber. This ionization of the air is likely to occur at the tip of the cut fiber. Therefore, in this embodiment, the tip of the static electricity removal cloth 15a facing the floor surface F is shaped like a sawtooth as shown in FIG. 5. This causes many tips of the cut fibers to face the floor surface F. In addition, since the acrylonitrile-copper sulfide composite fiber has a higher electrical resistance than metal, even if a user touches it, a sudden discharge is unlikely to occur. In addition, since the fibers of the static electricity removal cloth 15a are soft, they are less likely to damage the floor surface F, etc., even if they touch an object such as the floor surface F, compared to a static electricity removal needle or wire made of metal.

[0045] In this embodiment, the pitch La of the peaks 15a1 at the tip of the static neutralizing cloth 15a facing the floor surface F is set to 1 mm, and the height Lb is set to 2 mm. The tops 15a2 of the peaks 15a1 of the static neutralizing cloth 15a are set to have a vertical distance Lc of 6.0 mm from the floor surface F. That is, in this embodiment, the distance between the surface formed by the bottom surface of the housing 106 placed on the floor surface F and the tops 15a2 of the peaks 15a1 of the static neutralizing cloth 15a is set to the above-mentioned distance Lc. In addition, if the housing 106 is provided with a member such as wheels that is placed on the floor surface F, the distance between the surface formed by the contact portion of the wheels or the like with the floor surface F and the tops 15a2 may be set to the above-mentioned distance Lc. From the viewpoint of generating an appropriate electric field concentration to stably generate corona discharge, it is preferable that the distance La is approximately 2 mm or more. On the other hand, from the viewpoint of forming a shape that generates corona discharge at as many points as possible, it is preferable that the distance La is approximately 15 mm or less. Also, the distance Lb is preferably about 2 mm or more from the viewpoint of causing an appropriate electric field concentration to stably generate corona discharge, similar to the distance La. On the other hand, the distance Lb is preferably about 15 mm or less from the viewpoint of forming a shape that generates corona discharge at as many points as possible, similar to the distance La. Also, the distance Lc is preferably about 2 mm or more when a metal static elimination needle or wire is used as the static elimination member (see Examples 2 and 3) from the viewpoint of causing an appropriate electric field concentration to stably generate corona discharge. If the distance Lc is smaller than this, the discharge may be concentrated at one point, and a large current may flow. In this case, the static elimination member is provided so as to face the cleaning object without contacting the cleaning object. Also, when a static elimination member made of a material with a relatively high electrical resistance such as acrylonitrile-copper sulfide composite fiber is used as the static elimination member (this embodiment), the risk of a large current flowing is sufficiently low, so the distance Lc may be 0 mm and the static elimination member may be in contact with the cleaning object. In this case, the charge removing member is provided so as to face the object to be cleaned, either in contact with the object to be cleaned or in a non-contact manner with the object to be cleaned.On the other hand, when a metal static elimination needle or wire is used as the static elimination member (see Examples 2 and 3), the distance Lc is preferably 20 mm or less from the viewpoint of causing an appropriate electric field concentration to stably cause corona discharge. When a static elimination member made of a material capable of causing polarity transfer, such as acrylonitrile-copper sulfide composite fiber, is used, ions can be released from the tip of the static elimination member (fiber) into the atmosphere. Therefore, in this case, the distance Lc can be made longer than when the above-mentioned metal static elimination needle or wire is used, and the distance Lc is preferably 200 mm or less.

[0046] In this embodiment, the neutralizing cloth 15a is electrically connected to the core 11b of the brush roller 11, the base 12b of the collection roller 12, and the cleaning blade support 13b, which are made of a conductor, by the wiring W so that the neutralizing cloth 15a has the same potential as these conductive parts. As described above, when materials that are far apart in the triboelectric series are rubbed against each other, the two materials are charged. When the cleaning of the floor surface F is continued while the device body 101 is moved, electric charges are continuously accumulated on the raised nap 11a of the brush roller 11 and the surface layer 12a of the collection roller 12. The accumulated electric charges are transferred to the conductive parts through the phenomenon of dielectric polarization and micro-discharge, and the electric potential of the conductive parts increases in the negative direction. Here, since the conductive parts are connected to the neutralizing cloth 15a by the wiring W, the electric potential difference between the neutralizing cloth 15a and the floor surface F increases, which promotes the generation of electric discharge from the neutralizing cloth 15a and increases the effect of lowering the positive electric potential of the floor surface F.

[0047] In addition, since the static elimination cloth 15a is connected to the conductive portion by the wiring W, it is possible to prevent the electric potential of the conductive portion from rising too much. Therefore, it is possible to prevent the occurrence of a sudden discharge from the cleaning device 100 to the floor surface F and the occurrence of a spark discharge from the cleaning device 100 that is unpleasant for the user. From this viewpoint, it is desirable to arrange the static elimination unit 15 in a position as far away as possible from the handle 102 that the user touches, and further to arrange it in a position where the user cannot easily touch it. In this embodiment, the handle 102 is attached to the upper part of the housing 106, while the static elimination unit 15 is arranged adjacent to the static elimination opening 106d arranged in the lower part of the housing 106, and the static elimination unit 15 is away from the handle 102. In addition, in this embodiment, the static elimination unit 15 is arranged adjacent to the static elimination opening 106d that opens downward between the first housing 106a and the second housing 106b that constitute the housing 106 (approximately the center of the housing 106 in the cleaning direction D), and the possibility that the user will unintentionally touch the static elimination unit 15 is low.

[0048] In this embodiment, the housing 106 (first housing 106a and second housing 106b) is made of ABS resin. The wall 106c of the housing 106 is interposed between the charge removing unit 15 and the brush roller 11 or the collection roller 12 as a shielding unit, and prevents the movement of the air ionized by the charge removing unit 15. In other words, the wall 106c of the housing 106 prevents the air containing negative ions generated by the charge removing cloth 15a of the charge removing unit 15 from reaching the brush roller 11 or the collection roller 12. The material of this shielding unit may be an insulator or a conductor. In this embodiment, as described above, the wall 106c of the housing 106 as the shielding unit is made of ABS resin, which is an insulating resin material. With this configuration, it is possible to suppress the potential of the surfaces of the brush roller 11 and the collection roller 12 from decreasing, thereby suppressing the deterioration of the cleaning function.

[0049] In addition, in the case where a shielding portion such as the wall 106c of the housing 106 is not interposed between the brush roller 11 or the collection roller 12 and the charge removing unit 15, it is preferable to adopt the following configuration. That is, it is preferable to install the charge removing unit 15 (particularly the charge removing cloth 15a) at least 30 mm away from the brush roller 11 or the collection roller 12 (charged object). In other words, it is preferable to set the closest distance between the charge removing unit 15 (particularly the charge removing cloth 15a) and the brush roller 11 or the collection roller 12 to 30 mm or more. This makes it possible to suppress a decrease in the electric potential of the brush roller 11 or the collection roller 12 due to the air ionized by the charge removing unit 15.

[0050] (5) Evaluation experiment In order to verify the effect of this embodiment, a comparison was made between the configuration of this embodiment and the configurations of Comparative Example 1 and Comparative Example 2. The configuration of Comparative Example 1 does not have the static elimination unit 15 in the configuration of this embodiment. As shown in FIG. 6, the configuration of Comparative Example 2 is a configuration in which the static elimination unit 15, which has the same configuration as this embodiment, is arranged toward the space above the device body 101, not toward the floor surface F. In the configuration of Comparative Example 2, a static elimination opening 106e is provided on the top surface of the housing 106 (second housing 106b) at a position opposite to the static elimination opening 106d in this embodiment. The static elimination unit 15 is provided so that the static elimination cloth 15a is exposed to the outside of the housing 106 (second housing 106b) from the static elimination opening 106e. The configurations of Comparative Example 1 and Comparative Example 2 are substantially the same as the configuration of this embodiment, except for the above points. In Comparative Example 1 and Comparative Example 2, the elements having the same or corresponding functions or configurations as those of this embodiment are also described by using the same reference numerals.

[0051] The experiment was carried out as follows. The floor surface F to be cleaned was made of an insulating polycarbonate plate (2 mm thick) placed on aluminum connected to the ground potential (GND) (electrically grounded). In an area of ​​500 mm x 500 mm on this floor surface F, the device main body 101 was placed on the floor surface F and moved 200 mm in the cleaning direction D, then lifted up and returned, then placed on the floor surface F again and moved in the cleaning direction D, and this cleaning action was repeated. Then, the potentials of the conductive parts (core part 11b of the brush roller 11, base part 12b of the collection roller 12, and cleaning blade support part 13b) and the potential of the floor surface F after the cleaning action were measured. The results are shown in Table 2.

[0052] If the potential of the conductive part is up to about -1000V, the user will often not notice discharge from the cleaning device 100 to the user. If the potential of the conductive part is -3000V or higher, a discharge noticeable by the user may occur, and if the potential is -5000V or higher, a spark discharge that is unpleasant to the user may occur.

[0053] [Table 2]

[0054] In the configuration of Comparative Example 1, when the cleaning action was continued for 1 to 2 minutes, the potential of the conductive portion rose to -4500V, and the potential of the floor surface F after the passage of the device main body 101 rose to +2500V.

[0055] In the configuration of Comparative Example 2, when the cleaning action was continued for 1 to 2 minutes, the potential of the conductive part rose to -3000V, and the potential of the floor surface F after the device main body 101 passed rose to +1000V. This is considered to be due to the following reasons. In the configuration of Comparative Example 2, the sawtooth-shaped part of the static neutralizing cloth 15a is arranged facing upward, so that the negative ions generated near the tip of the static neutralizing cloth 15a stay there and become more concentrated, and the rate of ionization gradually slows down. Therefore, although it is lower than Comparative Example 1, the potential of the conductive part becomes relatively high, and the potential of the floor surface F also becomes relatively high.

[0056] In contrast, in this embodiment, the potential of the conductive portion after 1 to 2 minutes of continuous cleaning dropped to -200 V, and the potential of the floor surface F after the device body 101 passed also dropped to +100 V. This is believed to be because an efficient cycle was realized in which the negative charge of the cleaning device 100 itself was reduced and the positively charged floor surface F was neutralized.

[0057] In this manner, in this embodiment, the static elimination cloth 15a of the static eliminator 15 and the conductive portion are connected by the wiring W, which increases the static elimination effect on the floor surface F by the static eliminator 15, and can eliminate static electricity on the floor surface F to a lower potential. Furthermore, in this embodiment, negative charges accumulated in the cleaning device 100 can also be effectively released.

[0058] In this embodiment, the charge removing member (charge removing cloth) 15a is electrically connected to the core 11b of the brush roller 11, the base 12b of the collection roller 12, and the cleaning blade support part 13b, but is not limited to this. The charge removing member (charge removing cloth) 15a may be electrically connected to at least one of these conductive parts.

[0059] The resin material constituting the collecting member such as the nap of the brush roller is not limited to PET, and may be, for example, other polyester resins, or urethane resins, acrylic resins, polyethylene resins, polypropylene resins, etc. The resin material constituting the collecting member such as the surface layer of the collecting roller is preferably a fluororesin from the viewpoint of efficiently collecting the collected materials, but is not limited thereto, and may be, for example, a silicone resin, etc. The fluororesin is not limited to PFA, and may be, for example, PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), ETFE (tetrafluoroethylene-ethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), ECTFE (chlorotrifluoroethylene-ethylene copolymer), etc.

[0060] Thus, the electrostatic collection device (cleaning device) 100 of this embodiment is a rotatable collection rotor (brush roller) 11 equipped with a collection member (fuzz) 11a made of an insulator that comes into contact with the cleaning target (floor surface) F to form a collection portion P1. The collection rotor 11 rotates to rub the cleaning target F with the collection member 11a at the collection portion P1, collecting the matter (dust) H from the cleaning target F that moves relative to the collection portion P1 onto the collection member 11a, and has a removal member (collection roller 12, cleaning blade 13) that removes the matter H from the collection member 11a. The electrostatic collector 100 has a charge removing member (charge removing cloth) 15a arranged to face the cleaning target F downstream of the collecting unit P1 in the relative movement direction E of the cleaning target F with respect to the collecting unit P1, and the charge removing member 15a is electrically connected to a conductor (core 11a, base 12b, cleaning blade support 13b) that does not contact the cleaning target F and constitutes at least a part of at least one of the collecting rotor 11 and the removing members 12 and 13. In this embodiment, the collecting rotor 11 is constituted by a brush roller including a core 11b and a plurality of raised fibers 11a that are provided on the outer periphery of the core 11b and constitute the collecting member. In this embodiment, the charge removing member 15a is electrically connected to the conductor that constitutes the core 11b. In this embodiment, the removing member includes a first removing member (collection roller) 12 that collects the objects H from the collecting member 11a, and a second removing member (cleaning blade) 13 that removes the objects H collected by the first removing member 12 from the collecting member 11a, from the first removing member 12. In this embodiment, the discharging member 15a is electrically connected to a conductor that constitutes at least a part of at least one of the first removing member 12 and the second removing member 13.

[0061] In this embodiment, the charge removing member 15a is made of metal thread. Particularly, in this embodiment, the charge removing member 15a is made of acrylonitrile-copper sulfide composite fiber. In this embodiment, the tip of the charge removing member 15a facing the cleaning target F is formed in a sawtooth shape. In this embodiment, the electrostatic collector 100 has a shielding portion (wall 106c of the housing) that shields the collecting rotor 11 from the charge removing member 15a. The charge removing member 15a may be disposed at a position at least 30 mm away from the collecting rotor 11. The length of the charge removing member 15a in the longitudinal direction is preferably longer than the length of the region in which the collecting member 11a is provided in a direction substantially perpendicular to the direction in which the collecting rotor 11 moves around due to the rotation of the collecting rotor 11. In addition, it is preferable that the potential decay rate R1 of the surface of the collection member 11a after one rotation of the collection rotor 11, which is expressed by the following formula, R1=1-exp(-t1 / τ) [where t1 is the time required for the collection rotor to rotate once, and τ is a potential decay time constant, which is the time required for the surface potential of the collection member to decay to V0×(1 / e) when the surface of the collection member is charged to an initial potential V0 (e is the base of the natural logarithm)], is 10% or less. In this embodiment, the electrostatic collection device 100 collects dust H as the object to be collected from the cleaning target (floor surface) F.

[0062] As described above, according to this embodiment, the cleaning device 100 can efficiently remove electricity from the floor surface F that has been rubbed and charged by the bristles 11a of the brush roller 11. This makes it possible to prevent dust H from re-adhering to the floor surface F. Furthermore, according to this embodiment, it is possible to prevent excessive accumulation of electric charge in the cleaning device 100. This makes it possible to prevent sudden discharge from the cleaning device 100 to the cleaning target or the user.

[0063] [Example 2] Next, another embodiment of the present invention will be described. In this embodiment, the application of the electrostatic collector according to the present invention is different from that of embodiment 1. In this embodiment, the electrostatic collector according to the present invention is used as a paper dust collector that collects paper dust as a target to be collected from a recording material as a cleaning target in an image forming apparatus.

[0064] (1) Image forming device 7 is a schematic cross-sectional view of an image forming apparatus 200 that uses the electrostatic collector of this embodiment as a paper dust collector. In this embodiment, the image forming apparatus 200 is a monochrome laser beam printer capable of forming a black monochrome image using an electrophotographic method.

[0065] The image forming apparatus 200 has a photosensitive drum 201, which is a rotatable drum-type (cylindrical) photosensitive member (electrophotographic photosensitive member) serving as an image carrier. When an image output operation is started, the photosensitive drum 201 is driven to rotate in the direction of the arrow in the figure (clockwise direction). In this embodiment, the outer diameter of the photosensitive drum 201 is 30 mm, and the peripheral speed (surface moving speed) is 140 mm / sec.

[0066] The surface of the rotating photosensitive drum 201 is uniformly charged to a predetermined potential of a predetermined polarity (negative polarity in this embodiment) by a charging roller 202, which is a roller-type charging member serving as a charging means. The charging roller 202 comes into contact with the surface of the photosensitive drum 201 and charges the surface of the photosensitive drum 201 while rotating in the direction of the arrow in the figure (counterclockwise direction) in accordance with the rotation of the photosensitive drum 201.

[0067] The surface of the charged photosensitive drum 201 is scanned and exposed by an exposure device (laser scanner device) 203 as an exposure means, and an electrostatic latent image (electrostatic image) is formed on the photosensitive drum 201. The exposure device 203 irradiates the surface of the photosensitive drum 201 with a laser beam L modulated according to image data sent to the image forming apparatus 200 from an external device such as a personal computer.

[0068] The electrostatic latent image formed on the photosensitive drum 201 is developed (visualized) by supplying toner T as a developer by a developing device 204 as a developing means, and a toner image (toner image, developer image) is formed on the photosensitive drum 201. The developing device 204 causes the toner T conveyed by a developing roller 204a in contact with the photosensitive drum 201 to adhere to the electrostatic latent image on the photosensitive drum 201. During development, a predetermined development voltage is applied to the developing roller 204a by a developing high voltage power supply (not shown) as a developing voltage application means. In this embodiment, the toner T charged to the same polarity as the charging polarity of the photosensitive drum 201 (negative polarity in this embodiment) adheres to the exposed portion (image portion) on the photosensitive drum 201, the absolute value of the potential of which has been reduced by being exposed after being uniformly charged (reverse development method).

[0069] A transfer roller 205, which is a roller-type transfer member serving as a transfer means, is disposed so as to come into contact with the photosensitive drum 201. The transfer roller 205 comes into contact with the photosensitive drum 201 to form a transfer section (transfer nip section) N. The toner image formed on the photosensitive drum 201 is transferred in the transfer section N onto a sheet-like recording material S, such as paper, which is sandwiched between the photosensitive drum 201 and the transfer roller 205 and transported. During transfer, a predetermined transfer voltage of a polarity opposite to the normal charging polarity of the toner (main charging polarity during development, positive polarity in this embodiment) is applied to the transfer roller 205. The recording material S is sent out from a cassette 206, which serves as a recording material storage section, by a feed roller 207, which serves as a feeding means, etc., in synchronization with the toner image on the photosensitive drum 201, and is transported to the transfer section N by a transport roller 208, which serves as a transport means, etc.

[0070] The recording material S onto which the toner image has been transferred is sent to a fixing device 209 as a fixing means. The fixing device 209 applies heat and pressure to the recording material S carrying the unfixed toner image, thereby fixing (melting and bonding) the toner image onto the recording material S. The recording material S onto which the toner image has been fixed is discharged to the outside of the image forming apparatus 200.

[0071] Furthermore, negative toner (transfer residual toner) remaining on the photosensitive drum 201 without being transferred to the recording material S during transfer is collected by the developing device 204. The transfer residual toner adhering to the photosensitive drum 201 is transferred to the developing roller 204a due to the potential difference between the potential of the photosensitive drum 201 and the development voltage, and is collected from the developing roller 204a into the developing device 204 and is used again for image formation. Thus, in this embodiment, the image forming apparatus 200 has a cleaner-less configuration that does not have a dedicated cleaning device for removing the transfer residual toner from the photosensitive drum 201.

[0072] In the image forming apparatus 200 of this embodiment, the surface of the photosensitive drum 201 directly contacts the recording material S, so that paper dust P (FIG. 8) is likely to adhere to the surface of the photosensitive drum 201. In addition to pulp fiber (cellulose extracted from broadleaf trees and coniferous trees), which is the main raw material of paper, the paper dust P contains fillers for making the paper opaque or white, internal sizing agents for preventing ink bleeding, and internal sizing fixers for adsorbing the internal sizing agents to the pulp fibers. Among these, the substances that may have a particularly adverse effect on the electrophotographic process are the pulp fibers and fillers. If the paper dust P is collected in the developing device 204 together with the toner T remaining on the photosensitive drum 201, it may cause image defects. In other words, if the paper dust P is collected in the developing device 204, it may reduce the charge amount of the toner in the developing device 204. If the image forming operation is repeated in this state, the charge amount of the toner in the developing device 204 will become insufficient for the charge amount required for the image forming operation. If the amount of charge on the toner is insufficient, fog, in which the toner thinly adheres to areas (non-image areas) on the photosensitive drum 201 where an image is not originally formed, may occur beyond an acceptable range.

[0073] Therefore, the image forming apparatus 200 of this embodiment has a paper dust collecting device 10 configured as an electrostatic collector according to the present invention, which collects paper dust P as a collected object from the surface of the recording material S as a cleaning target. In this embodiment, the paper dust collecting device 10 is disposed in a feeding and conveying section of the recording material S. More specifically, in this embodiment, the paper dust collecting device 10 is disposed downstream of the cassette 206 and upstream of the transfer section N in the conveying direction of the recording material S. The paper dust collecting device 10 collects positively charged paper dust P from the surface of the recording material S. This makes it possible to suppress the occurrence of the fog described above.

[0074] The paper dust collecting device 10 may be configured to also function as a conveying means for the recording material S.

[0075] (2) Overall configuration of the paper dust collector Next, the paper dust collecting device 10 of this embodiment will be described. FIG. 8 is a schematic cross-sectional view of the paper dust collecting device 10 of this embodiment (a cross-section substantially perpendicular to the rotation axis direction of the brush roller 11 described later). The principle of the cleaning operation (paper dust collecting operation) by the paper dust collecting device 10 is the same as that of the cleaning device 100 of the first embodiment. In the paper dust collecting device 10 of this embodiment, elements having the same or corresponding functions or configurations as those of the cleaning device 100 of the first embodiment are given the same reference numerals as in the first embodiment, and detailed explanations are omitted as appropriate. In this embodiment, the conveying direction of the recording material S conveyed from the cassette 206 to the transfer unit N is the relative moving direction of the cleaning target with respect to the paper dust collecting device 10, that is, the cleaning target moving direction E. When the electrostatic collecting device according to the present invention is used in industrial products, such as the recording material S in this embodiment, the cleaning target moving direction is often fixed.

[0076] The paper powder collecting device 10 of this embodiment has a brush roller 11 which is a collecting rotor as a collecting means, a collecting roller 12 which is a first removal member (collection rotor) as a removing means, and a cleaning blade 13 which is a second removal member (scraping member), a storage container 14 which contains paper powder P, a static elimination section 15, and an opposing roller 16 for transporting a recording material S such as paper.

[0077] The brush roller 11 receives a driving force transmitted by a drive transmission member (not shown) from a motor (not shown) as a driving source constituting a driving means provided in the image forming apparatus 200, and rotates at a peripheral speed of 140 mm / sec (the same speed as the conveying speed of the recording material S) in the direction indicated by the arrow in the figure (clockwise direction). In other words, the brush roller 11 rotates such that the moving direction of the raised fibers 11a and the moving direction of the cleaning target (conveying direction of the recording material S) E are forward directions at a contact portion (collection portion) P1 between the raised fibers 11a and the recording material S. In addition, the recovery roller 12 receives a driving force transmitted by a drive transmission member (not shown) from a motor (not shown) as a driving source constituting a driving means provided in the image forming apparatus 200, and rotates at a peripheral speed of 140 mm / sec in the direction indicated by the arrow in the figure (counterclockwise direction). That is, the recovery roller 12 rotates so that the movement direction of the bristles 11a of the brush roller 11 and the movement direction of the surface of the recovery roller 12 are the same at the contact portion (recovery portion) P2 between the bristles 11a of the brush roller 11 and the recovery roller 12. While rotating, the brush roller 11 rubs the surface of the recording material S with the bristles 11a of the brush roller 11 that contact the surface of the recording material S, rubbing the surface of the recording material S and the paper dust P on the recording material S, and collects the paper dust P from the surface of the recording material S by electrostatic adhesion. In this embodiment, the bristles 11a of the brush roller 11 function as a collecting member that contacts the recording material S and rubs the recording material S. The paper dust P collected by the brush roller 11 is collected by the recovery roller 12 that rotates while contacting the brush roller 11 by electrostatic adhesion. In this embodiment, the surface layer 12a of the recovery roller 12 functions as a collecting member that collects the paper dust P from the bristles 11a of the brush roller 11. The paper powder P collected by the collection roller 12 is scraped off from the collection roller 12 by a cleaning blade 13 and stored in a storage container 14.

[0078] The configurations of the brush roller 11, the collection roller 12, and the cleaning blade 13 in the paper dust collecting device 10 of this embodiment are the same as those in the cleaning device 100 of the first embodiment, so a detailed description will be omitted. However, in this embodiment, the length in the longitudinal direction (rotation axis direction) of the brush roller 11 (area where the naps 11a are provided) and the collection roller 12 (surface layer 12a) is set to 220 mm so as to cover the entire area in the width direction substantially perpendicular to the conveying direction of the A4 size recording material S. Also, in this embodiment, an opposing roller 16 is disposed opposite the brush roller 11 so as to sandwich and convey the recording material S together with the brush roller 11. The opposing roller 16 may be one that is driven to rotate, or one that is driven to rotate.

[0079] Furthermore, the paper powder collecting device 10 of this embodiment has a static elimination unit 15 that is arranged at a position downstream of the brush roller 11 (and upstream of the transfer unit N) in the cleaning object movement direction (conveyance direction of the recording material S) E. That is, the static elimination unit 15 is arranged at a position downstream of the collection unit P1 (and upstream of the transfer unit N) in the measurement object movement direction (conveyance direction of the recording material S) E. The static elimination unit 15 constitutes a static elimination means that eliminates static electricity from the recording material S that has been rubbed by the brush roller 11. Details of the static elimination unit 15 in this embodiment will be described later.

[0080] (3) Static elimination means Next, the charge eliminating section 15 as the charge eliminating means in this embodiment will be further described.

[0081] First, the reason why the paper dust collecting device 10 used in the image forming apparatus 200 needs a discharging means for discharging the recording material S will be described. The brush roller 11 can exert a strong electrostatic adhesion force on the paper dust P, while the brush roller 11 also exchanges charges with the recording material S, so that the recording material S is once positively charged. When the positively charged recording material S is directly supplied to the transfer section N, the surface of the photosensitive drum 201 is charged to a negative potential by the charging roller 202, so the potential difference between the two becomes large. As a result, the paper dust P that cannot be completely removed by the paper dust collecting device 10 and remains on the recording material S is attracted to the surface of the photosensitive drum 201. The attracted paper dust P adheres to the photosensitive drum 201 and is collected by the developing device 204, reducing the charge amount of the toner in the developing device 204, which may eventually cause a fogged image as described above. Therefore, it is desirable to quickly remove static electricity from the recording material S after it has passed through the collecting portion P1, which is the contact portion between the bristles 11a of the brush roller 11 and the recording material S.

[0082] In this embodiment, the charge removal unit 15 is configured to have a charge removal needle 15a as a charge removal member and a charge removal needle support part 15b that supports the charge removal needle 15a. The charge removal needle 15a is supported by being sandwiched by the charge removal needle support part 15b. The configuration of the charge removal needle support part 15b in this embodiment is the same as that in the first embodiment. In this embodiment, the charge removal needle 15a as a charge removal member is formed of a plate material having a thickness of 0.1 mm that is made of SUS (stainless steel), which is a conductive metal material as a conductor. The shape of the charge removal needle 15a in this embodiment is the same as that of the charge removal cloth 15a in the first embodiment. That is, the shape of the tip of the charge removal needle 15a that faces the recording material S is serrated as shown in FIG. 5. In this embodiment, the pitch La, height Lb, and distance Lc between the top 15a2 and the surface of the recording material S of the peaks 15a1 of the tip of the charge removal needle 15a that faces the recording material S are the same as those in the first embodiment. The charge removing needle 15a is arranged in a direction intersecting (typically substantially perpendicular to) the cleaning target moving direction (conveying direction of the recording material S) E, that is, in a direction substantially parallel to the rotation axis direction of the brush roller 11. In this embodiment, the length of the charge removing needle 15a in the longitudinal direction is 225 mm, which is longer than the length of the region where the bristles 11a of the brush roller 11 are provided (and further the surface layer 12a of the collection roller 12). In other words, in the longitudinal direction of the charge removing needle 15a, the region where the bristles 11a of the brush roller 11 are provided (and further the surface layer 12a of the collection roller 12) is accommodated inside the charge removing needle 15a. This allows the recording material S charged by the brush roller 11 to be charged over the entire width direction of the recording material S. As in the first embodiment, the static elimination needle 15a is electrically connected to the core 11b of the brush roller 11, the base 12b of the recovery roller 12, and the cleaning blade support portion 13b, which are made of a conductor, by wiring W so that the static elimination needle 15a is at the same potential as these conductor portions.

[0083] (4) Evaluation experiment In order to verify the effect of this embodiment, a comparison was made between the configuration of this embodiment and the configurations of Comparative Example 3 and Comparative Example 4. The configuration of Comparative Example 3 does not have the static elimination unit 15 in the configuration of this embodiment. As shown in FIG. 9, the configuration of Comparative Example 4 is a configuration in which the static elimination needle 15a of the static elimination unit 15, which has the same configuration as this embodiment, is connected (electrically grounded) to the ground potential (GND) by the wiring G. The configurations of Comparative Example 3 and Comparative Example 4 are substantially the same as the configuration of this embodiment except for the above points. In Comparative Example 3 and Comparative Example 4, the same reference numerals are used to describe elements having the same or corresponding functions or configurations as those of this embodiment.

[0084] The experiment was carried out as follows. First, the potential of the charge removing needle 15a was measured after forming (passing) images on 10 sheets of recording material S in a normal printing operation. In addition, in order to evaluate the amount of paper dust P collected in the developing device 204, the amount of fogging was measured after forming (passing) images on 3000 sheets of recording material S. The amount of fogging (%) can be calculated from the difference between the amount of reflected light in a portion where fogging does not occur and the amount of reflected light in a portion where fogging occurs. The portion where fogging does not occur refers to a portion where a part of the printing surface side of the recording material S is masked with tape or the like, and the masking is peeled off after printing. If the amount of reflected light in a portion where fogging does not occur is 100% and the amount of reflected light in a portion where fogging occurs is 95%, the amount of fogging is 5%. A DENSITOMETER TC-6DS (manufactured by Tokyo Denshoku Technical Center) was used as a measuring device for the amount of reflected light. The amount of fogging is allowed to be within about 3%. The results are shown in Table 3.

[0085] [Table 3]

[0086] In the configuration of Comparative Example 3, the fog increased to 7%, exceeding the allowable level.

[0087] In the configuration of Comparative Example 4, the potential of the charge eliminating needle 15a is always kept at zero. In the configuration of Comparative Example 4, the fogging increased to 5%, exceeding the allowable level. This is thought to be because the recording material S after passing through the brush roller 11 was not sufficiently charged, and a large amount of paper powder P was collected in the developing device 204 by the above-mentioned mechanism.

[0088] In contrast, in this embodiment, the potential of the charge removal needle 15a after the printing operation was -500V. In this embodiment, the fogging was 2%, which was within the acceptable level. The reason why the fogging was improved in this embodiment is that the amount of paper dust P collected in the developing device 204 was reduced. In this embodiment, the charge removal needle 15a is connected to the conductive portion, so that the potential difference between the charge removal needle 15a and the recording material S is increased, which promotes the generation of discharge from the charge removal needle 15a and increases the effect of lowering the positive potential of the recording material S. As a result, the amount of paper dust P collected in the developing device 204 can be reduced by the above-mentioned mechanism.

[0089] In this manner, in this embodiment, the charge elimination needle 15a is electrically connected to the conductive portion so that it has the same potential as the conductive portion, thereby enhancing the charge elimination effect of the charge elimination needle 15a and achieving higher charge elimination performance.

[0090] In this embodiment, the configuration using the charge eliminating needle as the charge eliminating member has been described, but the present invention is not limited to this. For example, the corona charger may be configured using a discharge wire as the charge eliminating member (discharge member). In this case, any wire that can be used as the discharge wire of a corona charger can be used as the discharge wire, and for example, a tungsten wire with a thickness of about 30 μm can be preferably used. In addition, the charge eliminating member may be a charge eliminating cloth similar to that of the first embodiment. In this case, an assembly (nonwoven fabric) in which acrylonitrile-copper sulfide composite fibers similar to that of the first embodiment are assembled in a felt shape can be preferably used. In addition, the charge eliminating member such as the charge eliminating needle may be connected (electrically grounded) to a ground potential (GND) via a current suppressing element so that the potential of the charge eliminating member such as the charge eliminating needle does not become too high beyond a certain level. As the current suppressing element, a Zener diode, a varistor, a resistive element, or the like can be used. This makes it possible to suppress discharge from the charge eliminating member to members inside the device. As a result, it is possible to reduce the risk of defects such as image defects occurring. For example, from the viewpoint of enabling effective static elimination of the cleaning object while preventing the potential of the static elimination member (conductive portion) from rising too high, the potential of the static elimination member is preferably approximately -100V to -1000V (a negative potential with an absolute value of 100V or more and 1000V or less), and more preferably -200V to -500V (a negative potential with an absolute value of 200V or more and 500V or less).

[0091] As described above, according to this embodiment, in the paper dust collecting device 10, the recording material S that has been rubbed and charged by the bristles 11a of the brush roller 11 can be efficiently destaticized. This makes it possible to prevent the paper dust P that has not been collected and remains on the recording material S from adhering to the photosensitive drum 201 from the recording material S and being collected in the developing device 204. As a result, it is possible to prevent the occurrence of fogging due to a decrease in the amount of charge of the toner in the developing device 204.

[0092] [Example 3] Next, another embodiment of the present invention will be described. In this embodiment, as in the second embodiment, the electrostatic collector according to the present invention is used as a paper dust collector in an image forming apparatus. In the image forming apparatus and paper dust collector of this embodiment, elements having the same or corresponding functions or configurations as those of the image forming apparatus and paper dust collector of the second embodiment are given the same reference numerals as those of the second embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0093] FIG. 10 is a schematic cross-sectional view of a paper powder collecting device 20 of this embodiment (showing a cross section substantially perpendicular to the direction of the rotation axis of a collecting roller 17 described later).

[0094] The paper dust collector 20 of this embodiment differs from that of the second embodiment in that a collecting roller 17 having a similar configuration to the collecting roller 12 of the second embodiment is used as a collecting means that rotates in contact with a cleaning target to which the objects to be collected are attached and rubs against the cleaning target. In this embodiment, only a cleaning blade 13 having a similar configuration to that of the second embodiment is provided as a removing means for removing paper dust P, which is objects to be collected and is attached to the surface of the collecting roller 17, from the surface of the collecting roller 17. The configurations of the storage container 14, the charge removing unit 15, and the opposing roller 16 of this embodiment are the same as those of the second embodiment. According to this embodiment, a high effect can be obtained with a configuration having a smaller number of parts than the configuration of the second embodiment.

[0095] The configuration of the collection roller 17 as a collection unit in this embodiment is substantially the same as the configuration of the collection roller 12 in the second embodiment. That is, the collection roller 17 in this embodiment has a surface layer 17a having substantially the same configuration as the surface layer 12a of the collection roller 12 in the second embodiment, and a base portion 17b having substantially the same configuration as the base portion 12b of the collection roller 12 in the second embodiment. In this embodiment, the surface layer 17a of the collection roller 17 functions as a collection member that comes into contact with the recording material S and rubs against the recording material S. Also, in this embodiment, the collection roller 17 is configured such that the surface of the base portion 17b formed of a conductor is covered with the surface layer 17a formed of an insulator.

[0096] The collecting roller 17 receives a driving force transmitted by a drive transmission member (not shown) from a motor (not shown) serving as a driving source constituting a driving means provided in the image forming apparatus 200, and rotates in the direction indicated by the arrow in the figure (clockwise direction) at a peripheral speed of 140 mm / sec (the same speed as the conveying speed of the recording material S). That is, the collecting roller 17 rotates such that the moving direction of the surface of the collecting roller 17 and the moving direction of the cleaning target (conveying direction of the recording material S) E are the forward direction at a contact portion (collection portion) P1 between the collecting roller 17 and the recording material S. The collecting roller 17 conveys the recording material S together with the opposing roller 16 while rotating, and rubs the surface of the recording material S and the paper dust P on the recording material S to collect the paper dust P from the surface of the recording material S by electrostatic adhesion.

[0097] A difference from the second embodiment is that the surface of the collecting roller 17 as the collecting means is a smooth surface. If the surface of the collecting means is a smooth surface, the configuration of the removing means for removing the objects to be collected adhering to the surface of the collecting means from the collecting means can be simplified. Typically, as in this embodiment, the objects to be collected can be directly scraped off from the collecting means by the cleaning blade 13.

[0098] Also, similar to the case of the surface layer 12a of the collection roller 12 in the second embodiment, when the surface layer 17a of the collection roller 17 and the paper powder P rub against each other, the paper powder P is positively charged, and the surface layer 17a of the collection roller 17 is negatively charged. In this embodiment, a fluororesin that is located at the most negative side (or the position closest to the negative end) in the triboelectric series is used as the material for the surface layer 17a of the collection roller 17. Therefore, when the fluororesin and the paper powder P on the recording material S rub directly against each other, a stronger electrostatic adhesion force can be generated between them than in the case of the PET that constitutes the nap 11a of the brush roller 11 in the second embodiment.

[0099] Moreover, since the configuration of the static eliminator 15 in this embodiment is the same as that in the second embodiment, the same effects as those obtained by the static eliminator 15 in the second embodiment can be obtained in this embodiment as well.

[0100] In addition, when a collecting roller is used as in this embodiment, the material of the surface layer of the collecting roller is preferably fluororesin from the viewpoint of collecting performance, but is not limited thereto. For example, the material exemplified as the material of the nap of the brush roller in the first embodiment may be used, or the material exemplified as the material of the surface layer of the recovery roller in the first embodiment may be used.

[0101] Thus, in this embodiment, the collecting rotor (collecting roller) 17 is configured as a roller having a surface layer 17a constituting the collecting member and a base portion 17b provided inside the surface layer 17a. In this embodiment, the charge removing member (charge removing needle) 15a is electrically connected to a conductor constituting at least a part of the base portion 17b. In this embodiment, the removing member 13 is configured as a blade (cleaning blade) that removes the collected material (paper powder) P from the collecting member (surface layer) 17a. In this embodiment, the charge removing member 15a is electrically connected to a conductor constituting at least a part of the blade 13. In this embodiment, the charge removing member 15a is configured using a metal plate. In this embodiment, the electrostatic collecting device 10 collects paper powder P as the collected material from the surface of the recording material S as the cleaning target in the image forming device 200 that transfers a toner image formed on an image carrier 201 to the recording material S to form an image.

[0102] As described above, according to this embodiment, a stronger electrostatic adhesion force of the collection member (surface layer 17a of collection roller 17) can be obtained with a simpler configuration than that of the second embodiment.

[0103] [others] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the above-mentioned embodiments.

[0104] In the above-mentioned embodiment, the collecting rotor and the recovery rotor are brush rollers or rollers, but the collecting rotor and the recovery rotor made of an endless belt member may be used. For example, the collecting rotor may be a belt member having nap as a collecting member, or a belt member having a smooth surface layer as a collecting member, and the recovery rotor may be a belt member having a smooth surface. In this case, for example, at least one of the multiple tension rollers that stretch the belt member may be made of a conductor and connected to a charge removing member.

[0105] Furthermore, the collecting rotor in the cleaning device of the first embodiment may be a paddle roller having a core on the outer periphery of which a plurality of sheets are provided as collecting members along the rotational axis of the core.

[0106] In addition, the collecting rotor and the collecting rotor of the cleaning device in the first embodiment are driven by a motor, but the present invention is not limited to this. For example, the cleaning device may be configured such that the collecting rotor and the collecting rotor are rotated by the rotational force of the wheels that rotate as the cleaning device moves in contact with the cleaning target, and the driving source is not provided to the cleaning device.

[0107] Although the cleaning device in the first embodiment is used while being placed on the floor and pushed forward, it may be a lightweight handheld cleaning device (vacuum cleaner, handheld vacuum cleaner). In this case, too, the cleaning direction (i.e., the direction in which the cleaning target moves) can be predicted in advance depending on the attachment position and shape of the handle.

[0108] In addition, in the second and third embodiments, the image forming apparatus in which the electrostatic collector is used is a monochrome image forming apparatus, but it may also be, for example, a color image forming apparatus having a plurality of image forming units each equipped with an image carrier.

[0109] The electrostatic collector according to the present invention can be used for various applications other than those described in the above embodiments. For example, the electrostatic collector according to the present invention can be used in an image forming apparatus to collect paper dust adhering to the surface of an image carrier by making the collecting rotor contact the image carrier. In this case, the image carrier is not limited to a photosensitive drum, and may be, for example, an intermediate transfer belt that conveys a toner image that has been primarily transferred from the photosensitive drum to a recording material for secondary transfer. The electrostatic collector according to the present invention can be used in an image forming apparatus to collect paper dust from the surface of a belt that conveys a recording material by making the collecting rotor contact the surface of the belt. The electrostatic collector according to the present invention can also be used as a cleaning device in various manufacturing facilities, for example, for cleaning glass substrates and various insulators and conductors as cleaning targets. For example, when the electrostatic collector according to the present invention is used in such manufacturing facilities, the direction of movement of the cleaning target is often determined by moving at least one of the electrostatic collector or the cleaning target in a predetermined direction. [Explanation of symbols]

[0110] 10 Paper dust collection device 11 Brush roller (collecting rotor) 11a Raised (collection material) 11b Core (conductor part) 12 Recovery roller (first removal member, recovery rotor) 12a Surface layer (recovered material) 12b Base (conductor part) 13 Cleaning blade (second removing member, scraping member) 13b Cleaning blade support part (conductive part) 15 Static electricity removal section 15a Antistatic cloth, antistatic needle (antistatic material) 100 Cleaning equipment 200 Image forming device F Floor surface (to be cleaned) H Dust (object to be cleaned) P Paper dust (object to be cleaned) S Recording material (to be cleaned) W Wiring

Claims

1. a rotatable collecting rotor having a collecting member made of an insulating material that comes into contact with a cleaning target to form a collecting portion, the collecting rotor rotating to cause the collecting member to rub against the cleaning target in the collecting portion, and collect the objects to be collected from the cleaning target, which moves relative to the collecting portion, onto the collecting member; a removal member for removing the target material from the collection member; and An electrostatic collection device having a static elimination member disposed downstream of the collection unit in a relative movement direction of the cleaning target with respect to the collection unit so as to face the cleaning target, An electrostatic collection device, characterized in that the charge removal member is electrically connected to a conductor that constitutes at least a part of at least one of the collection rotor or the removal member and does not contact the object to be cleaned.

2. 2. The electrostatic collector according to claim 1, wherein the collector rotor is a brush roller having a core and a plurality of raised fibers provided on the outer periphery of the core and constituting the collector member.

3. 3. The electrostatic collector according to claim 2, wherein the charge removing member is electrically connected to the conductor constituting the core portion.

4. 3. The electrostatic collection device according to claim 2, wherein the removal member comprises a first removal member that collects the objects to be collected from the collection member, and a second removal member that removes the objects to be collected from the collection member by the first removal member from the first removal member.

5. 5. The electrostatic collector according to claim 4, wherein the charge removing member is electrically connected to a conductor constituting at least a part of at least one of the first removing member and the second removing member.

6. 2. The electrostatic collection device according to claim 1, wherein the collection rotor is a roller having a surface layer constituting the collection member and a base portion provided inside the surface layer.

7. 7. The electrostatic collector according to claim 6, wherein the charge removing member is electrically connected to a conductor that constitutes at least a part of the base.

8. 7. The electrostatic collector according to claim 6, wherein the removing member is a blade that removes the objects to be collected from the collecting member.

9. 9. The electrostatic collector according to claim 8, wherein the charge removing member is electrically connected to a conductor that constitutes at least a part of the blade.

10. 10. The electrostatic collector according to claim 1, wherein the charge removing member is made of metal thread.

11. 10. The electrostatic collector according to claim 1, wherein the charge removing member is made of acrylonitrile-copper sulfide composite fiber.

12. 10. The electrostatic collector according to claim 1, wherein the charge removing member is made of a metal plate.

13. 10. The electrostatic collector according to claim 1, wherein a tip of the charge removing member facing the object to be cleaned is formed in a sawtooth shape.

14. 10. The electrostatic collector according to claim 1, further comprising a shielding portion that shields the collector rotor from the charge removing member.

15. 10. The electrostatic collector according to claim 1, wherein the charge removing member is disposed at a position at least 30 mm away from the collector rotor.

16. 10. An electrostatic collection device according to claim 1, wherein the longitudinal length of the de-ionization member is longer than the length of the area in which the collection member is provided in a direction approximately perpendicular to the direction of circular movement of the collection member due to rotation of the collection rotor.

17. The potential attenuation rate R on the surface of the collection member after one revolution of the collection rotor is expressed by the following formula: １ 10. The electrostatic collector according to claim 1, wherein the ratio of the surface area to the surface area is 10% or less. R １ =1-exp(-t １ / τ) [In the above formula, t １ is the time required for the collection rotor to make one revolution, τ is the potential decay time constant, and is the time required for the surface of the collection member to be at the initial potential V ０ When the collection member is charged to ０ × (1 / e) (e is the base of the natural logarithm).

18. 10. The electrostatic collector according to claim 1, wherein the electrostatic collector collects dust as the object to be collected from the object to be cleaned.

19. 10. The electrostatic collector according to claim 1, in an image forming apparatus that forms an image by transferring a toner image formed on an image carrier onto a recording material, the electrostatic collector collecting paper dust as the object to be collected from the surface of the recording material as the cleaning target.

Images