JP2016197270A - Particle adhesion suppressing member and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a configuration that can suppress adhesion of particles (toner), while suppressing an increase in cost and size of an apparatus to which a toner adhesion suppressing member 990 as a particle adhesion suppressing member is assembled.SOLUTION: An insulation member 991I is attached to a connection member 991C as a conductive member having a constant potential. The insulation member 991I is formed of a porous material including EPDM and has a density of 0.01 g/cmor more and 0.2 g/cmor less. A toner P charged in the same polarity (negative polarity) as that of a toner which suppresses adhesion thereof is caused to adhere onto a free surface F of the insulation member 991I that is on the opposite side of the surface attached to the connection member 991C. Thus, the surface potential of the toner adhesion suppressing member 990 is increased in the direction of negative polarity so as to further suppress adhesion of the toner, and thereby adhesion of the toner can be suppressed without providing a device that applies a voltage.SELECTED DRAWING: Figure 8

Description

  The present invention relates to, for example, a particle adhesion suppressing member that suppresses adhesion of particles such as toner scattered in an image forming apparatus, and a copying machine, a printer, a facsimile, and a composite thereof including the particle adhesion suppressing member. The present invention relates to an image forming apparatus such as a printer.

  Conventionally, in an image forming apparatus to which an electrophotographic system is applied, a primary charging device, an exposure device, a developing device, a transfer device, a cleaning device, and the like are disposed along the peripheral surface of the photosensitive drum. The toner image formed on the photosensitive drum is transferred to the recording material directly or via an intermediate transfer belt. In such an image forming apparatus, powder toner is stored in a developing container of a developing device, and the toner is supplied to the photosensitive drum by rotating the developing sleeve.

  At this time, the toner is scattered by an electric field between the developing sleeve and the photosensitive drum, a centrifugal force of the developing sleeve, or the like. Further, the toner in the developing container may be blown out and scattered from the gap between the developing sleeve and the developing container due to an air flow generated by stirring the toner in the developing container.

  In the case of a configuration including an intermediate transfer belt, toner scattering may occur due to the toner being mechanically rubbed at the primary transfer portion, which is a contact portion between the photosensitive drum and the intermediate transfer belt. The same applies to the secondary transfer unit that transfers the toner image from the intermediate transfer belt to the recording material. Further, the toner image on the intermediate transfer belt may be scattered by centrifugal force as the intermediate transfer belt moves.

  The toner scattered in this way is usually collected by a filter provided in the exhaust fan. However, if the toner is scattered too much in the apparatus or adheres to a specific location, it may cause image defects or maintenance. It becomes difficult. For this reason, conventionally, techniques for suppressing such scattering and adhesion of toner have been proposed.

  For example, with respect to toner scattering from the gap between the developing sleeve and the developing container, there is a technique in which an electrode is provided on the surface facing the developing sleeve of the developing container and a bias having a voltage of the same polarity as the charging polarity of the toner is applied thereto. It has been proposed (Patent Document 1).

  In addition, by disposing a plurality of electrodes in the circumferential direction upstream of the developing position in the rotation direction of the photosensitive drum from the developing position, and applying an alternating voltage with a phase shift to this, toner scattering that occurs on the upper side of the developing device is prevented. The technique to do is proposed (patent document 2).

  In addition, there has been proposed a technique for preventing toner from adhering to the LED array light-emitting surface by providing electrodes around the LED array of the exposure apparatus and applying an alternating voltage (Patent Document 3).

  A technique for sucking scattered toner by using a suction device and a duct has been proposed (Patent Document 4).

  In addition, a conductive non-contact toner collecting member is provided on the recording material guide member upstream of the secondary transfer section, and by applying a strong bias to this, the scattered toner is collected to prevent toner contamination of the recording material. The technique to do is proposed (patent document 5).

JP-A-7-209987 JP-A-5-35112 JP 2006-239919 A JP 2007-33587 A JP 2008-3449 A

  However, as in the above-mentioned patent documents, in order to suppress scattering and adhesion of toner, if a device for applying a voltage, a device for sucking toner, a duct, and the like are provided, the device becomes expensive and large. End up.

  On the other hand, with the recent miniaturization of image forming apparatuses, it is difficult to introduce a technique that causes the apparatus to be enlarged as described above. Further, in the case of such a miniaturized apparatus, the interval between parts is narrow, and toner contamination is likely to occur. Therefore, the frequency of cleaning by the service person increases, and the time required for cleaning also increases, and the maintenance cost increases. In particular, in the case of a high-speed image forming apparatus, toner scattering tends to increase, and the maintenance cost tends to be higher.

  In view of such circumstances, the present invention has been invented to realize a configuration capable of suppressing the adhesion of particles while suppressing the increase in cost and size of an apparatus incorporating the particle adhesion suppressing member.

The present invention comprises a conductive member having a constant potential and an insulating member attached to the conductive member, and the insulating member is made of a porous material containing ethylene propylene diene terpolymer (EPDM), The density is 0.01 g / cm ³ or more and 0.2 g / cm ³ or less, and negatively charged particles adhere to the free surface side opposite to the side attached to the conductive member. It exists in the particle | grain adhesion suppression member characterized by the above-mentioned.

A conductive member having a constant potential; and an insulating member attached to the conductive member. The insulating member is made of a porous material made of a silicon material and has a density of 0.01 g / cm ³ or more, 0 ³ g / cm ³ or less, and negatively charged by adhering negatively charged particles to the free surface opposite to the side attached to the conductive member. It is in.

  According to the present invention, since negatively charged particles adhere to the free surface side of the insulating member, the insulating member can be negatively charged and particles can be further prevented from being attached. The adhesion of particles can be suppressed without any problems. As a result, it is possible to suppress the increase in cost and size of the apparatus incorporating the particle adhesion suppressing member, and it is possible to further reduce the maintenance cost of this apparatus.

1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic sectional view of the developing device. Similarly schematic sectional drawing of a cleaning apparatus. FIG. 3 is a schematic sectional view of the fixing device. FIG. 3 is a schematic cross-sectional view of the main part of the image forming apparatus for explaining the arrangement of the toner adhesion suppressing member. FIG. 6 is a schematic cross-sectional view showing the state of the relationship between the frame of the image forming apparatus and the image forming unit frame, as viewed from above in FIG. 5. The perspective view of the connection member which comprises the frame of an image forming apparatus similarly. Similarly, (a) exploded sectional view and (b) sectional view schematically showing a toner adhesion suppressing member. The enlarged view of an insulating member. FIG. 4 is a simple model for explaining a toner scattering suppression mechanism. The figure which shows the charging series of various materials. FIG. 5 is a schematic cross-sectional view of a developing device according to a second embodiment of the present invention. FIG. 10 is a schematic cross-sectional view of an image forming apparatus according to a third embodiment of the present invention. FIG. 2 is a schematic sectional view of the developing device. Similarly the expanded sectional view of a development blade. FIG. 6 is a diagram illustrating an example in which an output image is soiled with a lump of toner. FIG. 10 is a schematic cross-sectional view of a developing device showing another example of the third embodiment. The schematic structure sectional view of the cleaning device concerning a 4th embodiment of the present invention. Similarly the expanded sectional view of a cleaning blade support member. Sectional drawing which expands and shows the cleaning blade support member of the cleaning apparatus which concerns on the 5th Embodiment of this invention. FIG. 10 is a schematic cross-sectional view of a developing device according to a sixth embodiment of the present invention. Similarly, an enlarged perspective view of a toner adhesion suppressing member. The schematic structure sectional view of the cleaning member concerning a 7th embodiment of the present invention. Similarly, a schematic view in which a waterproof layer is provided on the toner adhesion suppressing member. FIG. 10 is a schematic cross-sectional view of an image forming apparatus according to an eighth embodiment of the present invention. The schematic structure sectional view of the cleaning device concerning a 9th embodiment of the present invention. FIG. 20 is a schematic cross-sectional view of a pre-exposure device according to a tenth embodiment of the present invention.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. First, a schematic configuration of the image forming apparatus according to the present exemplary embodiment will be described with reference to FIGS.

[Image forming apparatus]
An image forming apparatus 100 according to this embodiment is an electrophotographic printer, and includes a photosensitive drum 1 as an image carrier. The photosensitive drum 1 has a cylindrical shape with a diameter of, for example, 108 mm, and includes an a-Si (amorphous silicon) photosensitive layer on the surface. The photosensitive drum 1 is rotatably supported by a support member (not shown) and is driven to rotate at a predetermined peripheral speed, for example, 600 mm / s in the direction of arrow R1 by a drive unit (not shown). For example, when the A4 size recording material S is laterally fed, a black and white image can be formed at a maximum speed of 110 pages / minute. Further, the photosensitive drum 1 having an a-Si photosensitive layer has a higher durability (lifetime) than a photosensitive drum having an organic photo-semiconductive member (OPC) photosensitive layer used mainly in low- and medium-speed image forming apparatuses. Therefore, it is suitable for a high-speed image forming apparatus.

  The surface of the photosensitive drum 1 is neutralized by a pre-exposure device 6 a configured by an LED array 61 and the like, and then uniformly charged to a predetermined potential, for example, +500 V by a primary charging device 5, and then electrostatically charged by the exposure device 6. A latent image is formed.

  The exposure apparatus 6 includes a semiconductive member laser source (not shown) that emits a laser beam LB based on input image information. The laser beam LB is irradiated on the surface of the photosensitive drum 1 after the primary charging via a polygon mirror, an fθ lens, a folding mirror, a dustproof glass, etc. (all not shown), and an electrostatic latent image based on input image information is generated. It is formed. The wavelength of the laser beam LB is, for example, 670 nm, and the resolution is, for example, 600 dpi. The surface potential after exposure of the photosensitive drum 1 is, for example, about + 130V.

  Next, the electrostatic latent image is developed by a developing device 2 as a developing unit. The developer used in the present embodiment is a one-component type that does not include carrier particles and is composed only of magnetic toner. The toner is negatively chargeable and has a weight average particle diameter of 7 μm, for example.

  As shown in FIG. 2, the developing device 2 includes a resinous developing container (housing) 20, developing sleeves 21 a and 21 b as developer carriers made of nonmagnetic metal, and developer agitating and conveying members 22 a, 22 b, and 22 c. The developing blade 23 and the like.

  The toner in the developing device 2 is consumed as the image output is repeated, and the toner is supplied into the developing device 2 from a hopper (not shown). The replenished toner is rotated toward the developing sleeve 21a made of SUS304, for example, by rotating at a peripheral speed of, for example, 750 mm / s in the direction of arrow R21a by the rotating resin ladder-like developer stirring and conveying members 22a, 22b, and 22c. Be transported.

  The two developing sleeves 21a and 21b are cylindrical members having a diameter of 30 and 20 mm, for example, which are rotatably supported by the developing container 20 via bearings (not shown) and the like. Carrying the layer. In addition, a fixed permanent magnet (not shown) is incorporated inside.

  As the developing sleeve 21a rotates in the R21a direction, the toner carried on the developing sleeve 21a is conveyed to a gap G2 (for example, a distance of 230 μm) with the magnetic metal plate-like developing blade 23. The toner becomes a toner thin layer having a predetermined thickness while being negatively charged by the interaction between a fixed permanent magnet (not shown) built in the developing sleeve 21 a and the magnetic developing blade 23. Then, it is subjected to development in a gap G1a (for example, a distance of 250 μm) at a portion facing the photosensitive drum 1. A predetermined AC developing bias is applied to the gap G1a.

  As the developing sleeve 21b rotates in the R21b direction, the toner carried on the developing sleeve 21b is conveyed to a gap G22 (for example, a distance of 230 μm) with the developing sleeve 21a. The toner has a predetermined thickness while being negatively charged by the interaction between a fixed permanent magnet (not shown) built in the developing sleeve 21b and a fixed permanent magnet (not shown) built in the developing sleeve 21a. The toner is a thin layer. Then, it is subjected to development in a gap G1b (for example, a distance of 300 μm) at a portion facing the photosensitive drum 1. A predetermined AC developing bias is applied to the gap G1b.

  Thus, by supplying toner from the developing sleeves 21a and 21b, the electrostatic latent image formed on the photosensitive drum 1 as described above is developed with toner, and a toner image is formed on the photosensitive drum 1. The toner image formed on the photosensitive drum 1 is a resin-made image carrier or another image carrier at a contact portion (primary transfer portion) ZT1 between the photosensitive drum 1 and the primary transfer device (transfer means) 31. Primary transfer is performed on an endless belt-shaped intermediate transfer belt (intermediate transfer member) 39. The primary transfer device 31 is an elastic roller to which a primary bias voltage is applied, and is in pressure contact with the inner surface of the intermediate transfer belt 39, and the intermediate transfer belt 39 is in pressure contact with the photosensitive drum 1.

  A sheet-like recording material (another image carrier) S stored in a cassette 11 as a recording material storage device is fed one by one by a paper feed roller. The recording material S is transferred to a gap (secondary transfer portion) ZT2 between the intermediate transfer belt 39 and the secondary transfer device (transfer means) 3 via a conveyance roller, a registration roller, and the like. It is supplied in synchronization with the upper toner image. The toner image on the intermediate transfer belt 39 is secondarily transferred to the supplied recording material S by the secondary transfer device 3.

  The secondary transfer device 3 includes two rollers 32e and 32i made of an elastic body to which a secondary bias voltage is applied. The secondary transfer inner roller 32i is formed on the inner surface of the intermediate transfer belt 39 and the secondary transfer outer roller. 32e is in pressure contact with the outer surface of the intermediate transfer belt 39.

  The transfer residual toner on the photosensitive drum 1 is temporarily collected by a photosensitive drum cleaning device (cleaning means) 41, and the transfer residual toner on the intermediate transfer belt 39 is temporarily collected by an intermediate transfer belt cleaning device (cleaning means) 42, which is not shown. It is discharged to the recovery device.

  As shown in FIG. 3, the photosensitive drum cleaning device 41 includes a rubber plate-like cleaning blade 411 that collects transfer residual toner and the like on the drum while being pressed against the photosensitive drum 1. The toner collected by the cleaning blade 411 is temporarily stored in a cleaning container (housing) 410 that supports the cleaning blade 411. The toner collected in the cleaning container 410 is discharged to a collection container (not shown) by a rotating screw-shaped conveying member 414.

  Further, the photosensitive drum cleaning device 41 includes a permanent magnet roller 413 that rotates in the direction of an arrow R413 as a cleaning auxiliary unit. On the permanent magnet roller 413, magnetic spikes (not shown), which is a toner layer having a constant thickness, is formed by using the magnetic properties of the toner. The magnetic spikes are uniformly formed by a toner layer thickness regulating member 415 that rotates in the direction of arrow R415. Then, the transfer residual toner on the photosensitive drum 1 is rubbed and removed by the magnetic spikes.

  Although the detailed shape of the intermediate transfer belt cleaning device 42 is slightly different from that of the photosensitive drum cleaning device 41 in that the intermediate transfer belt 42 is in pressure contact with the intermediate transfer belt 39, the configuration itself is the same and the description thereof is omitted.

  As described above, a part of the toner remaining on the surface of the photosensitive drum 1 after the transfer of the toner image is removed by the photosensitive drum cleaning device 41. Thereafter, the photosensitive drum 1 is discharged by the above-described pre-exposure device 6a, and is again used for the next image formation.

  On the other hand, the recording material S after the toner image transfer is separated from the surface of the intermediate transfer belt 39 and conveyed to the fixing device 7 by the conveying belt 40. The recording material S is heated and pressurized by the fixing device 7 to fix the toner image on the surface. After the toner image is fixed, the recording material S is discharged from an image discharge port (not shown) to the outside of the image forming apparatus, whereby the formation of the toner image on one page of the recording material S is completed.

  As shown in FIG. 4, the fixing device 7 includes a fixing roller 71 as a rotating body provided with a fixing heater 73 serving as a heat source therein, and a pressure roller 72 as a rotating body pressed against the fixing roller 71. doing. Then, the current supplied to the fixing heater 73 is controlled by a control device (not shown) to adjust the surface temperature of the fixing roller 71, and the recording material S is nipped and conveyed at the nip portion between the fixing roller 71 and the pressure roller 72. During this time, the toner image is fixed by heating and pressing.

[Toner adhesion suppression member]
The toner adhesion suppressing member 990 as the particle adhesion suppressing member of the present embodiment will be described with reference to FIGS. Although the shape shown in FIG. 5 is different from the shape shown in FIG. 1, FIG. 5 is a schematic configuration diagram for explaining the arrangement of the toner adhesion suppressing member, and the basic configuration itself is the same as FIG. .

  In the present embodiment, the negatively charged particles are toner. Further, in the present embodiment, as shown in FIG. 5, it is difficult for toner to adhere to the lower surface of the connecting member 991C disposed below the photosensitive drum cleaning device 41, and between the connecting member 991C and the intermediate transfer belt 39. Therefore, the toner is prevented from scattering. That is, in the present embodiment, the toner adhesion suppressing member 990 is disposed below the photosensitive drum cleaning device 41 as a portion where the toner scatters, and downstream of the rotation direction (movement direction) of the photosensitive drum 1 of the primary transfer device 31 as a transfer unit. It is arranged. In this embodiment, as shown in FIG. 5, the photosensitive drum 1, the primary charging device 5, the exposure device 6, the developing device 2, the intermediate transfer belt 39, the pre-exposure device 6a, the photosensitive drum cleaning device 41, etc. An image forming unit 10 for forming an image is configured.

  As shown in FIG. 6, the image forming apparatus 100 according to the present embodiment forms an image such as the photosensitive drum 1, the primary charging device 5, the developing device 2, and the photosensitive drum cleaning device 41 except for the intermediate transfer belt 39 and the exposure device 6. The main elements of the unit 10 are enclosed by the image forming unit frame 99. The main elements of the image forming unit 10 and the image forming unit frame 99 constitute an image forming unit element unit 8. The image forming unit element unit 8 can be pulled out to the front side (the side operated by the user when the apparatus is installed, the lower side in FIG. 6) with respect to the frame 91 of the image forming apparatus 100.

  The image forming unit frame 99 includes a front plate member 99F, a back plate member 99R (upper side in FIG. 6), and connecting members 991C, 992C, and 993C that connect the two plate members 99F and 99R. Etc. As shown in FIG. 5, the connecting member 991C is a metal member located below the photosensitive drum cleaning device 41 and downstream of the moving direction R39 of the intermediate transfer belt 39 with respect to the primary transfer portion ZT1 during image formation. It is a plate-shaped member. Further, the connecting member 991C is grounded.

  As shown in FIG. 7, such a connecting member 991C is connected to two plate-like members 99F and 99R at both ends of a plate-like portion 991Ca having a width of 30 mm, a length of 340 mm, and a thickness of 1 mm, for example. Part 991Cb is provided. The basic function of the connecting member 991C is to maintain the strength of the image forming unit frame 99, but the toner scattered in the primary transfer unit ZT1 tends to adhere due to the arrangement in the image forming apparatus. Further, when the connecting member 991C is grounded as a countermeasure against electrostatic noise, the charged particles move along the lines of electric force and become more easily attached.

  In the case of the present embodiment, an insulating member 991I described below is attached to one side of the plate-like portion 991Ca of such a connecting member 991C to form a toner adhesion suppressing member 990. That is, since the connecting member 991C is a grounded metal plate-like member, the connecting member 991C is a conductive member having a constant potential (0 V). In other words, the connecting member 991C is a component that constitutes the image forming unit and functions as a conductive member. Note that the conductive member having a constant potential is not only grounded but may be a member to which a constant voltage (for example, +50 V) is applied, for example. As shown in FIG. 8, the insulating member 991I is bonded to the intermediate transfer belt 39 side of the connecting member 991C with an adhesive 991A. The adhesive 991A may be a conductive material or an insulating material.

  As shown in FIG. 5, the toner adhesion suppressing member 990 having the insulating member 991I attached to the connecting member 991C in this way has an intermediate transfer belt 39 with the surface of the insulating member 991I (the free surface F described below) as a counterpart member. It is in close proximity to the surface. In this embodiment, the distance d between the free surface F and the surface of the intermediate transfer belt 39 is 2 mm. As will be described later, the distance d is preferably small, for example, 10 mm or less, more preferably, in order to make it difficult for the toner to pass between the toner adhesion suppressing member 990 and the intermediate transfer belt 39 from the photosensitive drum 1 side. Is 5 mm or less. If the distance d is too small, the toner image on the intermediate transfer belt 39 may be affected. Therefore, the distance d is preferably 1 mm or more or 2 mm or more.

In the case of this embodiment, a porous material (foam) as shown in FIG. 9 containing an ethylene propylene diene terpolymer (EPDM) excellent in negative chargeability is used as the material of the insulating member 991I. . The density of the insulating member 991I is 0.2 g / cm ³ or less. The insulating member 991I has a volume resistivity of 10 ¹⁰ Ω · cm to 10 ¹⁶ Ω · cm. When the volume resistivity is less than 10 ¹⁰ Ω · cm, the insulation is insufficient, and the surface potential does not increase sufficiently even if toner adheres as described below. On the other hand, it is difficult to obtain an insulating material having a volume resistivity larger than 10 ¹⁶ Ω · cm. Therefore, the insulating member 991I of the present embodiment has a volume resistivity of 10 ¹⁰ Ω · cm or more and 10 ¹⁶ Ω · cm or less.

  Then, particles charged to the same polarity as the particles for suppressing adhesion are adhered to the free surface side opposite to the side attached to the connecting member 991C of the insulating member 991I. In the case of this embodiment, the particles that suppress adhesion are negatively charged toner. Therefore, a small amount of negative toner P (FIG. 8) is applied to the free surface F of the insulating member 991I (the lower surface of FIG. 5, FIG. 8). Directly attached to the upper surface of the substrate. This free surface is a surface that does not contact any part of the components of the apparatus.

  When a small amount of negative polarity toner P adheres to the free surface F of the insulating member 991I, the surface potential of the free surface F increases in the negative polarity direction (that is, the insulating member 991I is negatively charged). It becomes difficult to adhere. Actually, after the toner adhesion suppressing member 990 is installed, a small amount of toner scattered in the apparatus adheres to the free surface of the insulating member 991I, and the surface potential of the free surface increases. Thus, when the surface potential becomes high, it becomes difficult for the toner to adhere to the toner adhesion suppressing member 990 that also serves as the connecting member 991C. Further, it is difficult for the toner to pass between the toner adhesion suppressing member 990 and the intermediate transfer belt 39 from the photosensitive drum 1 side, and the toner can be prevented from scattering to the opposite side of the photosensitive drum 1 from the toner adhesion suppressing member 990. Further, the toner existing between the photosensitive drum 1 and the toner adhesion suppressing member 990 adheres to the photosensitive drum 1 and is collected by the photosensitive drum cleaning device 41, and the scattering of the toner is suppressed.

  In this embodiment, the length of the insulating member 991I (the length in the direction perpendicular to the direction in which the toner image is conveyed, the length in the width direction of the intermediate transfer belt 39, and the length in the front and back directions in FIG. 1) is set. The length of the image area formed on the intermediate transfer belt 39 is larger. For example, the length of the insulating member 991I is 340 mm, and the length of the image area is 300 mm. The reason for this will be described.

  As described above, in the present embodiment, an extremely small amount of negative polarity toner adheres to the foam satisfying the EPDM predetermined condition, thereby exhibiting an effect of suppressing toner adhesion. That is, it is preferable to dispose the toner adhesion suppressing member 990 at a position where charged toner is supplied to some extent. For this reason, the free surface F of the insulating member 991I is disposed to face a part of an image area where the toner image is conveyed by the intermediate transfer belt 39 as an image carrier that carries and moves the toner image. Further, the length of the insulating member 991I is made larger than the length of the image area. The charge amount of the toner adhering is preferably −1 μC / g or more (absolute value, that is, 1 μC / g or more on the negative polarity side).

  Examples of the binder used in the toner according to the exemplary embodiment include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-vinyl. Toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-ethyl acrylate-2-ethylhexyl Copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer Polymer, styrene-acrylonitrile copolymer, styrene Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Styrene copolymers such as maleic acid copolymer and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin , Polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. These binders are used alone or in combination.

  As the colorant used in the toner of the exemplary embodiment, all known ones can be used. For example, carbon black, iron black, graphite, nigrosine, monoazo dye metal complex, ultramarine, copper phthalocyanine, methylene blue, chrome. Dye pigments such as yellow, quinoline yellow, Hansa yellow, benzidine yellow, DuPont oil red, quinacridone, and various lake pigments can be used.

  In the case of nonmagnetic toner particles, the content of such a colorant is desirably about 2 to 30 parts by weight with respect to 100 parts by weight of the binder. Further, when contained in the magnetic toner, the amount is preferably about 0.5 to 15 parts by weight with respect to 100 parts by weight of the magnetic toner particles.

  The charge control agent is added as necessary to control the charge polarity and charge amount of the toner. In the present exemplary embodiment, a known appropriate charge control agent may be selected according to the polarity and charge amount of the target toner, and there is no particular limitation. For example, metal complex salt azo dyes, nigrosine dyes and the like can be mentioned, and these are selected according to required characteristics. The content of such a charge control agent is preferably about 0.2 to 10 parts by weight with respect to 100 parts by weight of the resin in the nonmagnetic toner particles. Further, when contained in the magnetic toner, it is desirable that the amount be about 0.2 to 10 parts by weight with respect to 100 parts by weight of the magnetic toner particles.

  Further, the wax is added as necessary as a mold release agent for fixing an image to prevent offset. For example, various known waxes such as polyethylene wax, polypropylene wax, and silicon wax may be used. Good. These are selected according to the required characteristics. The content of such wax is desirably about 2 to 10 parts by weight with respect to 100 parts by weight of the binder in the nonmagnetic toner particles. In the case of magnetic toner, it is desirable that the amount is about 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin.

  Select the necessary colorant, charge control agent, wax, magnetic powder, and other additives as described above, melt and knead these predetermined amounts and binder, after cooling, hammer mill, Roughly pulverize with a cutter mill or the like. Next, after further finely pulverizing with a jet mill, ang mill, etc., classification is performed so that a preferable volume average or number average particle diameter range is obtained.

  In addition to the above, if necessary, the toner that has been subjected to the classification process may include external additives or internal additives such as fluidity improvers, lubricants, abrasives, conductivity-imparting agents, and fixing aids. Is added. For example, silica, titanium oxide, resin powder as described above as toner binder, polytetrafluoroethylene powder, polyvinylidene fluoride powder, molybdenum disulfide, tungsten disulfide, boron nitride, lead oxide, antimony oxide, strontium sulfate, sulfuric acid Metal salts of higher resin acids such as aluminum, calcium carbonate, strontium titanate, cerium oxide, strontium oxide, zinc stearate, graphite, barium fluoride, calcium fluoride, carbon fluoride, carbon black, conductive tin oxide, etc. There are known fine particles, and some of them have two or more functions at the same time as the functional agent.

  The toner according to the exemplary embodiment can be mixed with carrier particles such as iron powder, glass beads, nickel powder, and ferrite powder as necessary, and used as a two-component developer. When the toner is used as a one-component magnetic developer, the magnetic powder includes ferromagnetic elements and alloys and compounds containing them, such as iron such as magnetite, hematite, and ferrite, cobalt, nickel, manganese, etc. A known magnetic material such as an alloy, a compound, or other ferromagnetic alloy may be contained. These magnetic powders are fine particles having an average particle diameter of 0.03 to 5 [mu] m, preferably 0.1 to 1 [mu] m, and are added at a ratio of 1 to 80% by weight, preferably 20 to 60% by weight of the toner weight.

[Toner scattering suppression mechanism]
Next, a mechanism for suppressing toner scattering by the toner adhesion suppressing member 990 will be described. First, as shown in FIG. 8 described above, an insulating member 991I that is a foam (FIG. 9) is attached to one surface of a connecting member 991C that is a conductive member having a constant potential (for example, 0 V), and the connecting member of the insulating member 991I is attached. A surface not attached to 991C is defined as a free surface F. Then, a very small amount of particles P (for example, toner) charged to a negative polarity (for example, −5 to −20 μC / g) are attached to the free surface F of the insulating member 9991I, thereby causing the negative surface (for example, toner) to have a strong negative surface (for example, toner). -2000V). Since the toner charged with the same polarity does not adhere to the charged surface, the charged surface itself does not become contaminated with toner, and because of the strong negative polarity, the toner hardly scatters in the vicinity of the charged surface.

  Next, the charging mechanism of the insulating member 991I will be described below. First, as in FIG. 8, two types of insulating members are attached to a metal plate (corresponding to the connecting member 991C) with a double-sided tape (corresponding to the adhesive 991A), and the two are compared. As the insulating member, a polyurethane foam was used as a comparative example, and an EPDM semi-independent semi-open cell was used as an example. Table 1 shows the surface potential of the insulating member when 0.001 g of negative polarity toner is attached to both.

  At this time, the charge amount of the toner was −5 μC / g. The charge amount of the toner was measured using a Faraday-Cage. The Faraday gauge is a coaxial and double cylinder, and the inner cylinder and the outer cylinder are insulated. If a charged body having a charge amount Q is put in the inner cylinder, it is the same as if a metal cylinder having a charge amount Q exists by electrostatic induction. This induced charge amount is measured by KEITHLEY 616 DIGITAL ELECTROMETER, and the toner weight M in the inner cylinder divided by the charge amount Q is defined as Q / M (charge amount). The toner was directly taken into the filter by air suction.

  As is clear from Table 1, the polyurethane foam of the comparative example is only charged with a surface potential of about −20 V or less, whereas the configuration using the EPDM foam of this embodiment is charged to −2000 V. To do. Note that the surface potential when the same toner is attached to the surface of the metal plate to which no insulating member is attached is -20V. Each member was examined after neutralizing with ethanol in order to make the initial conditions uniform.

Similarly, the surface potential of other materials was examined. The results are also shown in Table 1. As is apparent from Table 1, even with EPDM of the same material, a conductor such as E-4385 did not have a strong negative polarity. Although the rubber of company D is an insulator, it also did not have a strong negative polarity. Regarding the density, it was found that a low density of 0.2 g / cm ³ or less in EPDM shows a strong negative polarity, while a high density is not charged. Table 1 also shows the state of adhesion of toner other than a small amount of toner that adheres first. A cross mark of the toner adhesion state indicates that the toner has been largely adhered, and a circle mark indicates that the toner has hardly adhered.

As is clear from Table 1, among the materials examined, only EPDM with a density of 0.2 g / cm ³ or less had a negative surface potential and a good toner adhesion. That is, EPDM having a lower density is charged with a strong negative polarity. As a result, the negative polarity toner that subsequently flies becomes difficult to adhere due to electrostatic force.

FIG. 10 shows this phenomenon with a simple model. When toner having a charge of −Q [μC / g] adheres to the surface of the insulating member (EPDM foam), the surface potential V becomes V = Q / C [V]. C = ε (relative permittivity) × ε ₀ (vacuum permittivity) × S (area) / d (thickness).

Here, when the thickness d of the insulating member is 2 mm and the area surrounded by the outer edge of the free surface is S, the area excluding bubbles on the free surface of the insulating member depends on the density. For example, when the EPDM is a rubber material having a density of 0.9 g / cm ³ , the density is 1/10 in the case of a foam having an EPDM of 0.09 g / cm ³ . Here, if the height of the rubber material and the foam is constant, the area is about 1/10 (in reality, the density in the height direction is also reduced, so it is 1/10 or more).

On the other hand, the structure of the foam is complicated because the air layer and the sponge layer are mixed as shown in FIG. In terms of calculation, it is impossible to amplify the potential to about 100 times. However, as is apparent from Table 1, when EPDM is a rubber material having a density of 0.9 g / cm ³ , it is charged to −20 V, and when EPDM is a foam having 0.09 g / cm ³ , it is charged to −2000 V, respectively. To do. That is, the present inventor has discovered a configuration in which the insulating member has a limited configuration as described above, so that the amount of amplification is about 100 times that of a rubber material due to a small amount of charge.

Although such a structure cannot be explained quantitatively, it is considered that the apparent electric capacity becomes 1/100 of that of a rubber material by taking the limited foam structure having the above-described density and electrical properties. . According to the charging series shown in FIG. 11, EPDM has a property that tends to be negative in nature like polyethylene. Generally, a toner is made of a resin such as polyester or styrene acrylic, and EPDM has a characteristic that it is more easily charged negatively in a charge series than these. Therefore, as the insulating member, it is preferable to use a porous material that is charged more negatively than the resin constituting the toner (particles that suppress adhesion) and has a density of 0.2 g / cm ³ or less.

The density of the porous material is difficult to manufacture if the density is less than 0.01 g / cm ³ , and the density is unstable and the cell size is also unstable. Further, since a certain level of strength is required, the density of the insulating member is set to 0.01 g / cm ³ or more. A preferred range for the lower limit of the density of the insulating member, 0.03 g / cm ³ or more, and more preferable range is 0.05 g / cm ³ or more.

  As described above, since EPDM has a characteristic of being easily charged to a negative polarity, a small amount of negative polarity toner adheres to the surface of the insulating member that satisfies the above-described conditions, thereby creating a high negative potential surface layer. At the same time, by being insulated, the charge (potential) can be maintained at a negative polarity for a long time, so that the negatively charged toner is not further electrostatically adhered. In Table 1, when the toner adhesion state is round, 10000 images were formed and the surface potential of the insulating member was examined. As a result, the surface potential was charged to −1800 V. It was found that no toner smear occurred. Incidentally, even when a polytetrafluoroethylene tape, which is easily negatively charged, was stretched on a grounded metal, it was soiled because it did not show a strong negative charge. From this, it can be seen that this is a unique phenomenon.

  Next, the manufacturing method of the EPDM foam as an insulating member of this embodiment is demonstrated. First, the composition of the EPDM foam will be described. The EPDM foam is obtained by foaming a foaming composition containing ethylene / propylene / diene rubber, a vulcanizing agent, a vulcanization accelerator, a foaming agent and a foaming aid.

  EPDM is a rubber obtained by copolymerization of ethylene, propylene, and dienes, and vulcanization with a vulcanizing agent is performed by further copolymerizing dienes with an ethylene-propylene copolymer to form unsaturated bonds. It is possible. Examples of dienes include 5-ethylidene-2-norbornene, 1,4-hexadiene, dicyclopentadiene, and the like.

  The diene content of EPDM is, for example, 3 to 10% by weight. Examples of the vulcanizing agent include sulfur, selenium, magnesium oxide, lead monoxide, organic peroxides (for example, cumene peroxide), polyamines, oximes (for example, p-quinone dioxime, p, p ′). -Dibenzoylquinonedioxime, etc.), nitroso compounds (eg, p-dinitrosobenzidine, etc.), resins (eg, alkylphenol-formaldehyde resin, melamine-formaldehyde condensate, etc.), ammonium salts (eg, ammonium benzoate, etc.) ) And the like. From the viewpoint of durability resulting from the vulcanizability of the obtained EPDM foam, sulfur is preferably used. Vulcanizing agents may be used alone or in combination of two or more. The blending ratio of the vulcanizing agent may be selected as appropriate because the vulcanization efficiency varies depending on the type thereof. For example, sulfur is 0.5 to 3 parts by weight with respect to 100 parts by weight of EPDM.

  The vulcanization accelerator contains a thiourea vulcanization accelerator, a thiazole vulcanization accelerator, a dithiocarbamic acid vulcanization accelerator, and a thiuram vulcanization accelerator. Preferably, these four types of vulcanization accelerators are used. Consists only of agents.

  The thiourea vulcanization accelerator is selected from N, N'-diethylthiourea, N, N'-dibutylthiourea, N, N'-diphenylthiourea, and trimethylthiourea.

  The thiazole vulcanization accelerator is selected from 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, and dibenzothiazyl disulfide.

  The dithiocarbamic acid vulcanization accelerator is selected from zinc diisononyl dithiocarbamate and zinc dibenzyldithiocarbamate.

  The thiuram vulcanization accelerator is selected from tetrakis (2-ethylhexyl) thiuram disulfide and tetrabenzyl thiuram disulfide.

  The vulcanization accelerators are thiourea vulcanization accelerators, thiazole vulcanization accelerators, dithiocarbamic acid vulcanization accelerators and thiuram vulcanization accelerators, thiourea vulcanization accelerators / thiazole vulcanization accelerators. As a weight ratio of the agent / dithiocarbamic acid vulcanization accelerator / thiuram vulcanization accelerator, for example, a ratio of 1-20 / 1-20 / 1-20 / 1-30, preferably 1-15 / 1 It is contained in a ratio of 10/1 to 10/1 to 30, more preferably in a ratio of 2 to 15/2 to 7/1 to 5/1 to 25. Moreover, the mixture ratio of a vulcanization accelerator is 1.0-7.0 weight part with respect to 100 weight part of EPDM.

  Examples of the blowing agent include azo compounds such as azodicarbonamide (ADCA), barium azodicarboxylate, azobisisobutyronitrile (AIBN), azocyclohexylnitrile, and azodiaminobenzene, such as 4,4′- Oxybis (benzenesulfonylhydrazide) (OBSH), paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonylhydrazide, 2,4-toluenedisulfonylhydrazide, p, p-bis (benzenesulfonylhydrazide) ether, benzene- Hydrazide-based compounds such as 1,3-disulfonylhydrazide and allylbis (sulfonylhydrazide), such as p-toluylenesulfonyl semicarbazide and 4,4′-oxybis (benzenesulfonyl semicarbazide) Organic foaming agents such as micarbazide compounds, for example, fluorinated alkanes such as trichloromonofluoromethane, dichloromonofluoromethane, and triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole Bicarbonates such as sodium bicarbonate, ammonium bicarbonate, for example, carbonates such as sodium carbonate, ammonium carbonate, for example, nitrites such as sodium nitrite, ammonium nitrite, borohydrides such as sodium borohydride, etc. Examples thereof include inorganic foaming agents such as salts, for example, azides. Preferably, organic foaming agents, more preferably azo compounds, and even more preferably azodicarbonamide (ADCA).

  As the organic foaming agent, heat-expandable fine particles in which a heat-expandable substance is enclosed in a microcapsule may be used. Examples of such heat-expandable fine particles include microspheres (trade name, Commercial products such as Matsumoto Yushi Co., Ltd.) may be used. The blending ratio of the foaming agent is 5 to 25 parts by weight with respect to 100 parts by weight of EPDM. Examples of foaming aids include urea compounds, salicylic acid compounds, benzoic acid compounds, and the like. Preferably, a urea compound is used. The blending ratio of the foaming aid is, for example, 1 to 15 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of EPDM. Moreover, the foaming composition can contain a vulcanization auxiliary agent, a lubricant, a filler, a pigment, a softening agent and the like as necessary.

  Examples of the vulcanization aid include zinc oxide, and the blending ratio thereof is 2 to 10 parts by weight with respect to 100 parts by weight of EPDM. Examples of the lubricant include stearic acid and esters thereof, and the blending ratio thereof is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight with respect to 100 parts by weight of EPDM.

  Examples of the filler include calcium carbonate (for example, heavy calcium carbonate), magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silicic acid and salts thereof, clay, talc, mica powder, bentonite, silica. Inorganic fillers such as alumina, aluminum silicate, acetylene black, and aluminum powder, for example, organic fillers such as cork, and other known fillers, preferably inorganic fillers, more preferably May be calcium carbonate. The blending ratio of the filler is, for example, 200 parts by weight or less with respect to 100 parts by weight of EPDM.

  Examples of the pigment include carbon black, and the blending ratio is 0.5 to 50 parts by weight with respect to 100 parts by weight of EPDM.

  Examples of the softener include drying oils and animal and vegetable oils (for example, linseed oil), paraffin, asphalt, petroleum-based oils (for example, paraffin-based process oil, naphthenic process oil, and aroma-based process oil), Low molecular weight polymers, organic acid esters (eg, phthalate esters (eg, di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP)), phosphate esters, higher fatty acid esters, alkyl sulfonate esters, etc. ), Thickening agents, and the like, preferably paraffin, asphalt, and petroleum oils. The blending ratio of the softening agent is, for example, 50 to 200 parts by weight with respect to 100 parts by weight of EPDM.

  Furthermore, the foaming composition can be used, for example, in the range that does not affect the excellent effect of the obtained EPDM foam, for example, a plasticizer, an antioxidant, an antioxidant, a colorant, an antifungal agent, a difficult agent. Known additives such as a flame retardant can be appropriately contained.

  Next, a method for producing an EPDM foam will be described. In order to produce an EPDM foam, first, the above-described components are blended and kneaded using a kneader, a mixer, a mixing roll, or the like to prepare a foamed composition as an admixture. In the preparation step, kneading can be performed while appropriately heating. In the preparation step, for example, components other than the vulcanizing agent, the vulcanization accelerator, the foaming agent and the foaming aid are first kneaded to prepare the primary mixture, and then the vulcanizing agent and the vulcanizing agent are added to the primary mixture. A foaming composition (secondary mixture) can also be prepared by adding and kneading a sulfur accelerator, a foaming agent and a foaming aid. Moreover, when preparing a primary mixture, a part of vulcanization accelerator (for example, thiourea type vulcanization accelerator) can also be mix | blended.

The prepared foamed composition has a scorch time t ₅ (according to JIS K 6300-1) at 120 ° C. of, for example, 20 minutes or more, and preferably 30 minutes or more. Then, the prepared foamed composition is extruded into a sheet or the like using an extruder (molding process), and the extruded foam composition is heated and vulcanized and foamed (foaming process).

  Although a foaming composition is suitably selected by the vulcanization start temperature of the vulcanizing agent mix | blended, the foaming temperature of the foaming agent mix | blended, etc., for example, using a hot air circulation oven etc., for example, 60- After preheating at 160 ° C. for 5 to 40 minutes, it is heated at 120 to 250 ° C. for 15 to 50 minutes.

  Further, the prepared foamed composition can be continuously extruded into a sheet shape while being heated using an extruder, and the foamed composition can be continuously vulcanized and foamed. As a result, the foamed composition is vulcanized while foaming to form an EPDM foam.

  The density control of the foam can be controlled by the blending amount of the foaming agent, the treatment time and temperature of the vulcanized foam. Basically, the larger the amount of foaming agent, the easier it is to foam, and the higher the temperature and the longer the treatment time, the more foaming will proceed, and the optimum value will be adjusted.

  Further, the density can be adjusted in the permeation step before the heating step for foaming. The permeation step is a step of permeating an inert gas (for example, carbon dioxide gas) that becomes a foaming agent into a foam that is foamed under high pressure. By the way, the larger the amount of inert gas, that is, the permeation amount, the easier it is to foam.

  In addition, the manufacturing method of a foaming body is not restricted above, You may carry out with a well-known manufacturing method. Further, the silicon described later can be formed by the same method.

  Next, in the case where the member exposed to the scattered toner is only the conductive member, only the polyurethane insulating member, and the insulating member attached to the conductive member (product number: EC100), the toner adhesion state and the surface potential I investigated. The results are shown in Table 2.

  As is apparent from Table 2, it can be seen that only the insulating member that satisfies the conditions of this embodiment attached to the conductive member can effectively suppress toner adhesion.

  As described above, in the case of the present embodiment, it is possible to prevent further particles from adhering to the free surface side of the insulating member 991I by attaching the toner charged to the same polarity as the toner that suppresses adhesion. For this reason, toner adhesion can be suppressed without providing a device for applying a voltage. As a result, the cost and size of the image forming apparatus 100 incorporating the toner adhesion suppressing member 990 can be suppressed, and further, the maintenance cost of the apparatus can be suppressed.

[Example 1]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member 990, an insulating member 991I (product number EC100 in Table 1) having a width of 3 mm, a length of 340 mm, and a thickness of 1 mm is used as the connecting member 991C, and an adhesive (double-sided tape) having a thickness of 0.5 mm. A material bonded with 991A was used. Further, the distance d between the toner adhesion suppressing member 990 and the intermediate transfer belt 39 was set to 2 mm. The results of this experiment are shown as Example 1 in Table 3.

  The circles in Table 3 indicate that the cost of the apparatus was better than that of Conventional Example 3 (cross mark), which will be described later. It shows that it was better than conventional examples 1 and 2 (cross marks) described later. Also, regarding the maintenance cost, the circle indicates that it is better than the conventional examples 1 and 2 (cross mark). According to Table 3, Example 1 has a high cost advantage. In this way, it was possible to realize a configuration that is inexpensive and does not require cleaning maintenance by a service person.

[Conventional example 1]
Here, Conventional Example 1 in Table 3 will be described. In Conventional Example 1, no toner adhesion suppressing member is provided in any part of the image forming apparatus. In the case of Conventional Example 1, since the toner scatters and adheres to each part of the image forming apparatus, the maintenance frequency decreases (for example, cleaning is required for every 100,000 image outputs), and the maintenance cost decreases. To do.

  On the other hand, in Example 1, it was possible to suppress the scattering toner from adhering to the connecting member 991C, and furthermore, it was possible to suppress the toner scattering. In Embodiment 1, the distance d between the toner adhesion suppressing member 990 and the intermediate transfer belt 39 is reduced, and the gap through which the scattered toner can move is reduced. For this reason, the toner scattered in the primary transfer portion cannot move to the right side in FIG. 5 due to the electric field generated by the toner adhesion suppressing member 990, and is attracted to the photosensitive drum 1 side after the primary transfer. And finally, it is collected by the photosensitive drum cleaning device 41. Therefore, the toner can be prevented from scattering in the machine, and up to 10 million image outputs can be cleaned without service personnel.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, toner scattering that occurs on the downstream side in the rotation direction of the photosensitive drum 1 of the developing device 2 is reduced. For this reason, in this embodiment, a toner adhesion suppressing member 29 is provided below the opening 20c (near the opening) corresponding to the photosensitive drum 1 of the developing container 20 of the developing device 2. Further, foamed silicon is used as an insulating member constituting the toner adhesion suppressing member 29. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  In the case of the present embodiment, a toner adhesion suppressing member 29 is provided at a lower portion 20L of the opening 20c of the developing container 20 as a location where the toner in the apparatus scatters. In the present embodiment, since the developing container 20 is made of resin, the toner adhesion suppressing member 29 is an insulating member made of foamed silicon (particularly high-foamed silicon) on one side of a metal plate made of aluminum alloy or the like as a conductive member. For example, TL4400) in Table 1 is attached. The free surface of the insulating member is arranged below the developing container 20. The metal plate is grounded and kept at 0V.

The insulating member of the present embodiment is a porous material (foamed silicon) made of silicon and has a density of 0.3 g / cm ³ or less. As can be seen from Table 1 above, when the state of toner adhesion in the case of various materials made of insulating foam is used, a highly foamed silicon having a low density (for example, 0.26 g / cm ³ ) It was found that adhesion was suppressed. Such a material also has a high surface potential of -2000 V, which does not attract minus toner. However, even with foamed silicon, toner adhesion occurred in the case of TL4401 having a high density, for example, 0.34 g / cm ³ . From the detailed examination of the density, it was found that in the case of foamed silicon, toner adhesion can be suppressed when the density is 0.3 g / cm ³ or less. In this embodiment, this characteristic is used. Further, the lower limit of the density is set to 0.01 g / cm ³ or more from the viewpoint of firing stability and strength. A preferred range for the lower limit of the density of the insulating member, 0.03 g / cm ³ or more, and more preferable range is 0.05 g / cm ³ or more.

  According to the charging series shown in FIG. 11, silicon originally has a property that tends to be negative. Generally, the toner is made of a resin such as polyester, styrene, acrylic, etc., and silicon has a characteristic that it is more easily charged negatively in a charge series than these.

  Such a toner adhesion suppressing member 29 is adhered to the lower portion 20L of the developing container 20 with a double-sided tape. Thereby, the scattered toner does not adhere to the lower portion 20L. For this reason, it is possible to reduce the amount of scattered toner adhering to the lower portion 20L of the developing container 20 and accumulating and dropping below the developing container 20, and the toner image on the intermediate transfer belt 39 disposed below the developing container 20 can be reduced. Can be reduced.

  Further, the scattered toner generated between the developing sleeves 21a and 21b and the photosensitive drum 1 during the developing process goes to the lower side of the developing container 20 due to the strong negative polarity of the toner adhesion suppressing member 29 provided in the lower portion 20L. Hateful. For this reason, the scattered toner is attracted to the developing sleeves 21a and 21b after the developing process, and therefore, toner scattering on the lower side of the developing container 20 can be reduced.

[Example 2]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member 29, a porous insulating member (silicon foam, product number TL4400) adhered to an aluminum plate as a conductive member with a double-sided tape was used. The aluminum plate has a rectangular shape with a width of 3 mm, a length of 340 mm, and a thickness of 0.5 mm. The insulating member has a width of 3 mm, a length of 340 mm, and a thickness of 1 mm. The double-sided tape has a thickness of 0.5 mm. The results of this experiment are shown as Example 2 in Table 3 above.

  In the second embodiment, the toner contamination in the developing device and the machine is extremely improved as compared with the conventional example 1, and the maintenance frequency due to the cleaning in the machine is reduced to 1/10 or less. As a result, the maintenance cost can be reduced. It was.

<Third Embodiment>
A third embodiment of the present invention will be described with reference to FIGS. The image forming apparatus 200 of the present embodiment is a tandem type full color image forming apparatus capable of forming a full color image at a speed of up to 40 sheets / minute, for example. For this purpose, image forming units 10Y, 10M, 10C, and 10K that form toner images of four primary colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. In this embodiment, the developer to be used is a two-component developer composed of a nonmagnetic toner and a magnetic carrier.

  These image forming units 10Y to 10K form corresponding color images, but the configuration is substantially the same. Therefore, the details of the image forming unit 10Y will be described below, and the other image forming units 10M to 10K will be described. Is omitted.

  The image forming unit 10Y includes a photosensitive drum 1Y, a primary charging device 5Y, a developing device 2Y, a primary transfer device 31Y, and the like. The photosensitive drum 1Y having the OPC photosensitive layer has, for example, a diameter of 30 mm and forms an electrostatic latent image on the surface thereof by a laser beam from an exposure device (laser scanner) 6Y. The peripheral speed is, for example, 250 mm / s.

  The primary charging device 5Y prepares an electrostatic latent image by charging the surface of the photosensitive drum 1Y to a predetermined potential, for example, −700V. The developing device 2Y develops the electrostatic latent image on the photosensitive drum 1Y to form a toner image.

  As shown in FIG. 14, the developing device 2Y includes a developing sleeve 21Y as a developer carrier, two conveying screws 22Y as a developer agitating and conveying member, and a layer thickness regulating member in a developing container 20Y. Development blade 23Y and the like. The developing sleeve 21Y has a diameter of 20 mm, for example, and a fixed magnet 24Y is disposed inside. Further, it is rotationally driven in the direction of arrow R21Y by a driving means (not shown). The conveying screws 22Y are respectively disposed in the stirring chamber 25Y and the developing chamber 26Y, and convey the developer in parallel and in opposite directions. Communication portions are provided at both ends of the agitating chamber 25Y and the developing chamber 26Y, and the developer circulates between the agitating chamber 25Y and the developing chamber 26Y through these communicating portions.

  The developer agitated and conveyed in the agitating chamber 25Y and the developing chamber 26Y is charged with a negative polarity toner and a positive polarity carrier. Then, it is carried and conveyed on the developing sleeve 21Y by the magnetic force of the magnet 24Y. At this time, the developer carried on the developing sleeve 21Y is conveyed to the photosensitive drum 1Y in a state where the layer thickness is regulated by the developing blade 23Y. Then, by applying a predetermined developing bias between the developing sleeve 21Y and the photosensitive drum 1Y, the electrostatic latent image on the photosensitive drum 1Y is developed with toner. The developer remaining on the developing sleeve 21Y after the development is collected in the developing chamber 26Y.

  The primary transfer device 31Y is a roller disposed at a position facing the photosensitive drum 1Y with the intermediate transfer belt 39 interposed therebetween. A predetermined primary transfer bias is applied to the roller, whereby the toner image formed on the photosensitive drum 1Y is primarily transferred to the intermediate transfer belt 39.

  Thereafter, the respective color toner images formed in the respective image forming units 10Y to 10K in the order of M, C, and K are primarily transferred onto the intermediate transfer belt 39 to form a full-color toner image. The toner image formed on the intermediate transfer belt 39 is secondarily transferred to the recording material S by the secondary transfer device 3. The secondary transfer device 3 includes two rollers 32e and 32i made of an elastic body to which a secondary bias voltage is applied. The secondary transfer inner roller 32i is formed on the inner surface of the intermediate transfer belt 39 and the secondary transfer outer roller. 32e is in pressure contact with the outer surface of the intermediate transfer belt 39.

  The transfer residual toner on the photosensitive drum 1Y is temporarily collected by the photosensitive drum cleaning device 41Y, and the transfer residual toner on the intermediate transfer belt 39 is temporarily collected by the intermediate transfer belt cleaning device 42 and discharged to a collection device (not shown). The recording material S to which the toner image has been transferred is conveyed to the fixing device 7 and is pressed and heated by the fixing device 7, whereby the image is fixed on the recording material S.

As described above, the developer of this embodiment includes a magnetic carrier and a nonmagnetic toner, and the toner is negatively charged. Further, the mass per unit area of the developer layer formed on the developing sleeve 21Y is, for example, about 50 mg / cm ² .

The toner includes a binder resin, a colorant, colored resin particles containing other additives as necessary, and colored particles to which an external additive such as colloidal silica fine powder is externally added. The binder resin is, for example, a negatively chargeable polyester resin, and the volume average particle diameter is, for example, 7 μm. The carrier particles are made of a material mainly composed of oxide ferrite, for example, and are not limited by the manufacturing method. The weight average particle diameter is, for example, 40 μm, and the volume electric resistance is, for example, 10 ⁸ Ω · cm.

  In the case of this embodiment, a toner adhesion suppression member 230Y is provided in the developing blade 23Y as a layer thickness regulating member of the developing device 2Y as a location where the toner in the device scatters to reduce toner scattering in the upstream portion of the developing device. Yes. As shown in FIG. 15, the toner adhesion suppressing member 230Y is obtained by attaching an insulating member 230YI similar to that of the first embodiment to the magnetic metal plate 230YC as a conductive member with an adhesive. The insulating member 230YI is fixed to the back side of the developing blade 23Y (the side on which the developer is conveyed by the developing sleeve 21Y) so that the free surface of the insulating member 230YI faces the inside of the developing container 20Y.

  Thereby, it is possible to reduce the toner sticking to the back side of the developing blade 23Y. That is, when toner adheres to the back side of the developing blade 23Y and the toner accumulates and becomes a large accumulation layer, the accumulated toner may fall at once. In some cases, the toner scatters from a portion where there is a gap in the developing container 20Y, for example, between the opening of the developing container 20Y and the developing sleeve 21Y or from the gap between the seal portions of the developing sleeve at the end. Further, such a toner lump may fall and the output image T on the intermediate transfer belt 39 may become dirty as shown in FIG. In the present embodiment, since the toner adhesion suppressing member 230Y is provided on the back side of the developing blade 23Y, occurrence of such a situation can be reduced. The same applies to other image forming units.

  As described above, the developer of this embodiment is a two-component type, and there is no magnetic force of toner on the developing sleeve 21Y. For this reason, the present embodiment is effective for a case where toner scattering is severe at the time of high temperature and high humidity when the charge amount of the toner is low.

  Note that the toner adhesion suppressing member 230Y as described above may be provided outside the portion of the developing container 20Y that covers the developing sleeve 21Y, as shown in FIG. That is, the toner adhesion suppressing member 230Y is provided in a portion covering the developing sleeve 21Y above the opening of the developing container 20Y. Thereby, scattering of the toner above the developing device 2Y can be suppressed.

[Example 3]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, a porous adhesion member (foam, product number EE-1010) bonded to the magnetic metal plate as the conductive member with a double-sided tape was used as the toner adhesion suppressing member. The magnetic metal plate has a rectangular shape with a width of 20 mm, a length of 320 mm, and a thickness of 1 mm. The insulating member has a width of 20 mm, a length of 320 mm, and a thickness of 5 mm. The double-sided tape has a thickness of 0.5 mm. The result of this experiment is shown as Example 3 in Table 3 above. In Example 3, by attaching a toner adhesion suppressing member to the back of the developing blade, toner adhesion to the back of the developing blade could be greatly reduced.

[Conventional example 2]
Here, Conventional Example 2 in Table 3 will be described. Conventional Example 2 is an image forming apparatus having the same configuration as that of the third embodiment, and no toner adhesion suppressing member is provided in any part of the image forming apparatus. In the case of the conventional example 2, since the toner is scattered and adheres to each part of the image forming apparatus, the maintenance frequency is reduced (for example, cleaning is required every about 50,000 sheets of image output), and the maintenance cost is reduced. To do. Further, in the case of Conventional Example 2, the toner released from the carrier on the developing sleeve is scattered in the developing process between the developing sleeve and the photosensitive drum. This was particularly noticeable when an AC bias was applied.

  On the other hand, in the third embodiment, it is possible to reduce the amount of adhered toner having a low charge amount falling outside the developing device and contaminating the output image, so that the maintenance frequency is lower than the conventional example 2, and the maintenance cost is also reduced. Declined.

<Fourth Embodiment>
A fourth embodiment of the present invention will be described with reference to FIGS. In the present exemplary embodiment, a toner adhesion suppressing member 412 is provided in the inside of the photosensitive drum cleaning device 41 as a cleaning unit, particularly in a portion that supports the cleaning blade 411 as a location where the toner in the apparatus scatters. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  The cleaning blade 411 is supported by a metal cleaning blade support member 412C, and the conductive member of the toner adhesion suppressing member 412 is the cleaning blade support member 412C. In other words, the cleaning blade support member 412C constitutes an image forming unit and serves as a component that functions as a conductive member. The cleaning blade support member 412C is formed by bending a plate-like member and has a shape as shown in the figure. Then, an insulating member 412I similar to that of the first embodiment is attached with a double-sided tape 412A (FIG. 19) so as to cover the surface of the cleaning blade support member 412C (the back surface excluding the surface that supports the cleaning blade 411). Yes. The free surface of the insulating member 421I also covers the surface of the cleaning blade support member 412C. Further, the cleaning blade support member 412C is grounded and kept at 0V.

  In the case of the present embodiment, by configuring in this way, it is possible to suppress the residual toner from accumulating on the upper wall surface in the photosensitive drum cleaning device 41 and preventing the toner from being scattered or the output image from being stained. That is, the residual toner on the photosensitive drum 1 is removed by the cleaning blade 411, passes through the permanent magnet roller 413, and is sent to the outside of the photosensitive drum cleaning device 41 by the conveying member 414. Thus, the toner is scattered inside the photosensitive drum cleaning device 41 until the toner is sent to the outside of the photosensitive drum cleaning device 41. When the scattered toner adheres to the upper surface in the photosensitive drum cleaning device 41 and the number of images formed increases, the toner accumulates here. As a result, for example, accumulated toner attached to the back surface of the cleaning blade support member 412C falls onto the permanent magnet roller 413 and the transport member 414 that stably supply the toner amount on the photosensitive drum 1 at a time. Then, there is a possibility that the toner scatters from the end of the photosensitive drum cleaning device 41 onto the intermediate transfer belt 39, and consequently the output image is soiled. In the present embodiment, since the cleaning blade support member 412C is covered with the insulating member 412I as described above, the scattered toner is unlikely to accumulate on the cleaning blade support member 412C, so that it is possible to suppress toner scattering and contamination of the output image.

[Example 4]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member, a porous insulating member (foam, product number No. 681) 412I adhered to the surface of the cleaning blade support member 412C as a conductive member with a double-sided tape 412A was used. The cleaning blade support member 412C is a nonmagnetic metal plate formed by bending a rectangle having a width of 340 mm, a length of 60 mm, and a thickness of 1 mm. The insulating member 412I has a width of 340 mm, a length of 58 mm, and a thickness of 2 mm. The double-sided tape 412A has a thickness of 0.5 mm. The result of this experiment is shown as Example 4 in Table 3 above.

  In Example 4, since the cleaning blade support member 412C also serves as the toner adhesion suppressing member 412, toner adhesion to the back surface of the cleaning blade support member 412C can be significantly reduced. Further, in Conventional Example 1, the accumulated toner attached to the back surface of the cleaning blade support member falls onto the permanent magnet roller and the conveying member at once, and the toner is scattered from the end of the photosensitive drum cleaning device onto the intermediate transfer belt. Was dirty. On the other hand, in Example 4, the amount of scattered toner was extremely reduced as compared with Conventional Example 1, and as a result, the maintenance frequency was reduced and the maintenance cost could be reduced.

<Fifth Embodiment>
A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, similarly to the fourth embodiment, a toner adhesion suppressing member 412 is provided in a portion where the cleaning blade 411 is supported by the photosensitive drum cleaning device 41. That is, the insulating member 412Ia similar to that of the first embodiment is attached by the double-sided tape 412A so as to cover the surface of the cleaning blade support member 412C (the back surface excluding the surface that supports the cleaning blade 411). However, unlike the fourth embodiment, the insulating member 412Ia is provided by being divided into cleaning blade support members 412C. Thereby, even in the case of a conductive member which is not a flat plate and is composed of a complicated curved surface or the like, the adhesiveness of the insulating member can be maintained, and the toner adhesion and scattering prevention performance can be maintained for a long time. Other configurations and operations are the same as those of the above-described fourth embodiment.

[Example 5]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member, a porous insulating member (foam, product number No. 681) 412Ia divided on the surface of a cleaning blade support member 412C as a conductive member and bonded with a double-sided tape 412A was used. . Various materials are the same as those in Example 4. The results of this experiment are shown as Example 5 in Table 3 above. Also in the case of the present example, the maintenance frequency was lowered and the maintenance cost was lowered.

<Sixth Embodiment>
A sixth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the toner adhering suppression member is disposed on the inner surface of the opening 27Y of the developing container 20Y of the developing device 2Y on the side wall 20SY (near the opening) facing the developing sleeve 21Y as a location where the toner in the apparatus scatters. 290Y is provided. Since the other basic configuration of the image forming apparatus is the same as that of the above-described third embodiment, the following description will focus on differences from the third embodiment.

  As shown in FIG. 22, the toner adhesion suppressing member 290Y is obtained by attaching an insulating member 290YI similar to that of the first embodiment to the magnetic metal plate 290YC as a conductive member with an adhesive. The insulating member 290YI is fixed to the side wall portion 20SY of the developing container 20Y so that the free surface of the insulating member 290YI faces the developing sleeve 21Y side.

  In FIG. 21, the toner adhesion suppressing member 290Y is installed at a distance of 2 mm from the surface of the developing sleeve 21Y as a counterpart member, and is upstream of the rotation direction R21Y of the developing sleeve 21Y from the vicinity of the take-in pole N3 of the magnet 24Y. Provided. Thereby, since the developer does not touch the toner adhesion suppressing member 290Y, the amount of scattered toner can be suppressed without causing image unevenness.

  In this embodiment, the toner adhesion suppressing member 290Y is provided close to the portion where the developer spike between the developing electrode S2 and the take-in electrode N3 lies. For this reason, the toner adhesion suppressing member 290Y can be installed closer to the developing sleeve 21Y than provided at a position facing the magnetic pole. In the above description, the Y image forming unit has been described, but the same applies to other image forming units.

  In the present embodiment, the toner adhesion suppressing member 290Y is provided on the side wall 20SY (near the opening) facing the developing sleeve 21Y. However, the present invention is not limited to this. In the developing device, it can be appropriately provided at a location where toner scattering is considered. For example, in order to suppress toner scattering from the end portion of the developing sleeve, the porous insulating member of the present invention may be attached to the end portion of the developing sleeve or the container surface facing the end portion of the developing sleeve. Also in this case, the free surface of the porous insulating member is attached and used so as not to contact the opposing member.

[Example 6]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, a porous adhesion member (foam, product number EE-1010) bonded to the magnetic metal plate as the conductive member with a double-sided tape was used as the toner adhesion suppressing member. The magnetic metal plate has a rectangular shape with a width of 20 mm, a length of 320 mm, and a thickness of 1 mm. The insulating member has a width of 20 mm, a length of 320 mm, and a thickness of 5 mm. The double-sided tape has a thickness of 0.5 mm. The result of this experiment is shown as Example 6 in Table 3 above.

  In Example 6, compared to Conventional Example 2 in which the toner adhesion suppressing member 290Y is not provided, the toner scattering amount can be suppressed to about 1/5 or less. In addition, the maintenance frequency is reduced and the maintenance cost is reduced as compared with the conventional example 2. Further, compared with Conventional Example 3 in Table 3, the apparatus cost was reduced by the amount that the high voltage power source for applying a high voltage to the toner adhesion suppressing member could be omitted.

[Conventional Example 3]
Here, Conventional Example 3 in Table 3 will be described. Conventional Example 3 is an image forming apparatus having the same configuration as that of the sixth embodiment, and is made of a nonmagnetic metal having a thickness of 0.5 mm instead of the toner adhesion suppressing member 290Y at the same position as that of the sixth embodiment. A plate-like member was installed at a distance of 2 mm from the surface of the developing sleeve 21Y. A DC voltage of −1000 V is applied to this member from a high voltage power supply (not shown). In the case of the conventional example 3, although there is a certain degree of toner scattering suppression prevention effect (cleaning is required every about 50,000 pages of image output), the apparatus cost is high for the high-voltage power supply.

<Seventh Embodiment>
A seventh embodiment of the present invention will be described with reference to FIGS. In the present embodiment, as a location where the toner in the apparatus scatters, a plate-like support member 47 that supports the intermediate transfer belt cleaning device 42 has a side surface 47U on the path side on which the recording material after the secondary transfer is conveyed. An insulating member 47I similar to that of the first embodiment is provided. That is, the toner adhesion suppressing member 470 is disposed downstream of the rotation direction (movement direction) of the intermediate transfer belt 39 of the secondary transfer device 3 as a transfer unit. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  In the present embodiment, the support member 47 is a grounded metal plate-like member, and is a conductive member having a constant potential (0 V). In other words, the support member 47 is a component that constitutes the image forming unit and functions as a conductive member. A toner adhesion suppressing member 470 is formed by attaching an insulating member 47I to the support member 47. In the case of the present embodiment, the free surface (the lower surface in FIG. 23) of the insulating member 47I is a waterproof layer (water) as a coat layer having higher smoothness than the surface of the insulating member 47I, as shown in FIG. Stopping layer) 47W. That is, as shown in FIG. 24, the toner adhesion suppressing member 470 has an insulating member 47I attached to a metal support member 47 with an adhesive 47A such as acrylic resin, and the surface of the insulating member 47I is further covered with a waterproof layer 47W. Covering. This waterproof layer is an insulating material, for example, formed by melting and extruding polyethylene glycol or polypropylene glycol on an acrylic adhesive layer. You may form by the lamination method of a film. Then, particles charged in the same polarity as the particles to suppress adhesion (negative toner in this embodiment) are adhered to the surface of the waterproof layer 47W.

  In the present embodiment, since the toner adhesion suppressing member 470 is provided below the intermediate transfer belt cleaning device 42, the toner scattered from the intermediate transfer belt 39 is more intermediate than the intermediate transfer belt cleaning device 42. It becomes difficult to scatter on the opposite side. Further, since the scattered toner is less likely to adhere to the lower support member 47 of the intermediate transfer belt cleaning device 42, it is possible to prevent the image of the recording material conveyed under the intermediate transfer belt cleaning device 42 from being stained. That is, there is a possibility that the toner scattered from the intermediate transfer belt 39 adheres to and accumulates on the side surface 47U of the support member 47, and the accumulated toner falls and stains the output image. On the other hand, in this embodiment, since scattered toner does not easily adhere to the side surface 47U, it is possible to prevent the output image from being stained in this way.

  In the case of this embodiment, since the waterproof layer 47W is provided on the surface of the toner adhesion suppressing member 470, the surface property is good, and it is easy for a serviceman to wipe the toner adhesion suppressing member 470 during maintenance. Therefore, maintainability by the service person is improved.

[Example 7]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, a porous adhesion member (foam, product number SA-612) 47I bonded to the surface of a support member 47 as a conductive member with a double-sided tape was used as a toner adhesion suppressing member. The layer thickness of the insulating member 47I is 5 mm. The layer thickness of 47 W of the waterproof layer (formed by melting and extruding polyethylene glycol on the acrylic adhesive layer) is about 100 μm to 500 μm. 0.001 g of negative polarity toner was applied to the surface of the waterproof layer 47W. The surface potential at this time was -1600V. The results of this experiment are shown as Example 7 in Table 3 above. In Example 7, since the surface potential was −1800 V, it was found that the negative toner was not brought closer. In addition, the maintenance frequency is lower than that of the conventional example 1, and the maintenance cost is also reduced.

<Eighth Embodiment>
An eighth embodiment of the present invention will be described with reference to FIG. In this embodiment, a toner adhesion suppressing member 390 similar to that of the first embodiment is provided below the intermediate transfer belt 39 as a location where the toner in the apparatus scatters. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  The toner adhesion suppressing member 390 is formed by attaching an insulating member 39I to a plate-like member 39C as a conductive member disposed below the intermediate transfer belt 39. The free surface of the insulating member 39I faces a part of the image area where the toner image is conveyed by the intermediate transfer belt 39. Further, the distance d between the free surface and the surface of the intermediate transfer belt 39 as the counterpart member is set to 1 mm or more and 10 mm or less (2 mm in this embodiment), as in the first embodiment.

  In the case of the present embodiment, the scattered toner from the intermediate transfer belt 39 or the like is less likely to adhere to the plate-like member 39C, so this toner accumulates on the plate-like member 39C, and the accumulated toner falls and stains the output image. Can be suppressed.

[Example 8]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member 390, an insulating member 39I (product number E-4382 in Table 1) bonded to a plate-like member 39C with an adhesive (double-sided tape) having a thickness of 0.5 mm. Was used. Further, the distance d between the toner adhesion suppressing member 390 and the intermediate transfer belt 39 was set to 2 mm. The results of this experiment are shown as Example 8 in Table 3. In Example 8, toner scattering can be reduced compared to Conventional Example 1, maintenance frequency can be reduced, and maintenance cost can be reduced.

<Ninth Embodiment>
A ninth embodiment of the present invention will be described with reference to FIG. In this embodiment, a toner adhesion suppressing member 419 is provided on the outer bottom portion 410EB of the cleaning container 410 of the photosensitive drum cleaning device 41 as a location where the toner in the apparatus scatters. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  As in the first embodiment, the toner adhesion suppressing member 419 is formed by attaching an insulating member to a conductive member, and is fixed to the lower surface of the outer bottom portion 410EB of the photosensitive drum cleaning device 41. The free surface of the insulating member faces the surface of the intermediate transfer belt 39. Further, the toner adhesion suppressing member 419 is arranged downstream of the rotation direction (movement direction) of the photosensitive drum 1 as the image carrier that carries and moves the toner image of the primary transfer device 31 (see FIG. 1) as transfer means. Has been.

  In the photosensitive drum cleaning device 41 disposed downstream of the photosensitive drum 1 in the primary transfer portion in the rotation direction, charged toner generated immediately after transfer is likely to adhere to various places in the apparatus. For this reason, the scattered toner from the intermediate transfer belt 39 or the like accumulates on the outer bottom portion 410EB, and the toner may fall and stain the output image. In this embodiment, since the toner adhesion suppressing member 419 is provided so as to cover the lower surface of the outer bottom portion 410EB, the scattered toner is less likely to adhere to the outer bottom portion 410EB, and the output image can be prevented from becoming dirty.

[Example 9]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member 419, a conductive member having a 1 mm thick insulating member (product number E-4382 in Table 1) bonded with a 0.5 mm thick adhesive (double-sided tape) was used. . The results of this experiment are shown as Example 9 in Table 3. In Example 9, toner contamination was reduced as compared with Conventional Example 1, and as a result, maintenance frequency was reduced and maintenance costs could be reduced.

<Tenth Embodiment>
A tenth embodiment of the present invention will be described with reference to FIG. In the present embodiment, a toner adhesion suppressing member 620 is provided in the vicinity of the opening 62a of the duct 62 that guides the light of the LED array 61 that constitutes the pre-exposure device 6a as a location where the toner in the apparatus scatters. Since the other basic configuration of the image forming apparatus is the same as that of the above-described first embodiment, the following description will focus on differences from the first embodiment.

  The pre-exposure device 6a as an exposure unit includes an LED array 61 as a light emitting unit that emits exposure light, and a duct 62 that guides the exposure light emitted from the LED array 61 to the photosensitive drum 1. The pre-exposure device 6a is used as pre-exposure used to return the potential on the photosensitive drum 1 (see FIG. 5) to a constant level. Also, as shown in FIG. 5, before the cleaning, which is arranged below the photosensitive drum cleaning device 41 and cancels the potential of the photosensitive drum 1 before the cleaning in order to assist the cleaning performance of the photosensitive drum cleaning device 41. It can also be used for exposure.

  In any case, similarly to the first embodiment, the toner adhesion suppressing member 620 is formed by attaching an insulating member to the conductive member, and is fixed to the photosensitive drum cleaning device 41 side in the vicinity of the opening 62a of the duct 62. The Below the pre-exposure device 6a, a toner adhesion suppressing member 990 in which an insulating member 991I is attached to the connecting member 991C is disposed as in the first embodiment. Note that the color of the insulating members of the toner adhesion suppressing members 620 and 990 is preferably black. As a result, dirt is less noticeable, and flare caused by reflection can be suppressed during exposure.

  In the present embodiment, since the toner adhesion suppressing member 620 is provided as described above, scattered toner from the intermediate transfer belt 39 and the like is less likely to adhere to the LED array 61. If the LED array 61 becomes dirty, the amount of light may decrease, and the photosensitive drum 1 may not be sufficiently neutralized. However, in the present embodiment, the scattered toner is difficult to adhere to the LED array 61, so the neutralization performance is degraded. Can be suppressed.

  Further, the connecting member 991C disposed below the pre-exposure device 6a is not soiled, the number of cleanings by the service person is reduced, and exposure that assists the cleaning performance can always be maintained. For this reason, there is no deterioration in the cleaning performance, and the number of times the service person is dispatched can be reduced.

  In addition to the pre-exposure apparatus, the present embodiment can be applied to an exposure apparatus (exposure unit) for forming an electrostatic latent image on the photosensitive drum. For example, the present invention can be similarly applied to an exposure apparatus that is arranged around a photosensitive drum and draws an electrostatic latent image using exposure light from an LED array. Even in such a case, it is possible to prevent the scattered toner from adhering to the LED array by providing the toner adhesion suppressing member as described above in the vicinity of the opening of the duct for guiding the exposure light of the LED array to the photosensitive drum. . If the LED array becomes dirty, the amount of light may decrease and image unevenness may occur. However, by providing the toner adhesion suppressing member as described above, the occurrence of such image unevenness can be suppressed.

[Example 10]
Next, experimental results in which the configuration of the present embodiment is actually applied will be described. In the experiment, as the toner adhesion suppressing member 620, a conductive member obtained by bonding a 1 mm thick insulating member (product number E-4382 in Table 1) with an adhesive (double-sided tape) having a thickness of 0.5 mm was used. . The results of this experiment are shown as Example 10 in Table 3. In Example 10, the maintenance frequency was reduced and the maintenance cost could be reduced as compared with Conventional Example 1.

<Other embodiments>
The above-described embodiments can be implemented in combination as appropriate. Also, the insulating member can be appropriately changed within the range of the material that satisfies the present invention. Further, the particle adhesion suppressing member of the present invention can be applied to other than the image forming apparatus described above. For example, it can be used to suppress adhesion of particles other than toner. In addition, regarding the electrical resistance / shape / density / arrangement of the insulating member, the shape / arrangement of the toner adhesion suppressing member, the presence / absence of the adhesive / electrical resistance, etc., the purpose, environment, and mode of use of the image forming apparatus It can be appropriately changed according to the above. Further, it is possible to select an optimum one for the peripheral speed and charging polarity of the photosensitive drum and the intermediate transfer belt, the presence / absence of the intermediate transfer belt, and the like according to the use purpose, use environment, use mode, and the like of the image forming apparatus.

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum (image carrier) 10, 10Y, 10M, 10C, 10K ... Image forming part 2, 2, Y, 2M, 2C, 2K ... Developing device (developing means), 20, 20Y 20M, 20C, 20K ... developing container, 21Y, 21M, 21C, 21K ... developing sleeve (developer carrier), 23Y, 23M, 23C, 23K ... developing blade (layer thickness regulating member), 3 ... Secondary transfer device (transfer means) 31, 31Y, 31M, 31C, 31K ... Primary transfer device (transfer means), 39 ... Intermediate transfer belt (image carrier, another image carrier) ), 39C... Plate-like member (conductive member), 41... Photosensitive drum cleaning device (cleaning device), 42... Intermediate transfer belt cleaning device (cleaning device), 47. ), 47W: waterproof layer (coat layer), 6 ... Pre-exposure device (exposure means), 61 ... LED array (light emitting part), 62 ... Duct, 29, 230Y, 290Y, 390, 412, 419, 470, 620, 990 ... Toner adhesion Suppression member (particle adhesion suppression member), 230YC, 290YC ... magnetic metal plate (conductive member), 412C ... cleaning blade support member (conductive member), 991C ... connecting member (conductive member), 39I, 47I , 230YI, 290YI, 412I, 412Ia, 991I ... insulating member, 100 ... image forming apparatus, F ... free surface, S ... recording material (another image carrier)

Claims (14)

A conductive member having a constant potential;
An insulating member attached to the conductive member,
The insulating member is made of a porous material made of ethylene propylene diene terpolymer, and has a density of 0.01 g / cm ³ or more and 0.2 g / cm ³ or less, and a side attached to the conductive member; Is negatively charged by adhering negatively charged particles to the opposite free surface,
A particle adhesion suppressing member characterized by the above. A conductive member having a constant potential;
An insulating member attached to the conductive member,
The insulating member is made of a porous material made of silicon, has a density of 0.01 g / cm ³ or more and 0.3 g / cm ³ or less, and is a free surface side opposite to the side attached to the conductive member. And negatively charged by adhering negatively charged particles,
A particle adhesion suppressing member characterized by the above. The insulating member has a volume resistivity of 10 ¹⁰ Ω · cm or more and 10 ¹⁶ Ω · cm or less.
The particle adhesion suppressing member according to claim 1 or 2, characterized in that Directly attaching the particles to the free surface of the insulating member;
The particle adhesion suppressing member according to any one of claims 1 to 3, wherein the particle adhesion suppressing member is characterized in that The free surface of the insulating member has a coat layer having higher smoothness than the surface of the insulating member.
The particle adhesion suppressing member according to any one of claims 1 to 3, wherein the particle adhesion suppressing member is characterized in that An image forming unit for forming a toner image;
A particle adhesion suppressing member disposed at a location where the toner in the apparatus scatters,
The particle adhesion suppressing member is the particle adhesion suppressing member according to any one of claims 1 to 5.
An image forming apparatus. The insulating member of the particle adhesion suppressing member constitutes the image forming unit and is attached to a component functioning as the conductive member.
The image forming apparatus according to claim 6. The image forming unit has an image carrier that carries and moves a toner image;
The free surface of the insulating member is disposed to face a part of an image area where a toner image is conveyed by the image carrier.
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The insulating member is disposed at a position where the free surface faces the mating member and a distance between the free surface and the mating member is 1 mm or more and 10 mm or less.
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes an image carrier that carries and moves a toner image, and a transfer unit that transfers the toner image from the image carrier to another image carrier.
The particle adhesion suppressing member is disposed downstream of the transfer unit with respect to the moving direction of the image carrier.
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes an image carrier that carries and moves a toner image, a transfer unit that transfers a toner image from the image carrier to another image carrier, and the image that has been transferred to the transfer unit. A cleaning means for cleaning the surface of the carrier,
The particle adhesion suppressing member is disposed inside the cleaning means.
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes an image carrier that carries and moves a toner image, and a developing unit that develops the electrostatic latent image formed on the image carrier with toner,
The developing means includes a developing container that contains toner and has an opening in a portion facing the image carrier.
The particle adhesion suppressing member is disposed in the vicinity of the opening,
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes an image carrier that carries and moves a toner image, and a developing unit that develops the electrostatic latent image formed on the image carrier with toner,
The developing means includes a developer carrying body that moves while carrying a developer containing toner, and a layer thickness regulating member that regulates the layer thickness of the developer carried on the developer carrying body,
The particle adhesion suppressing member is disposed on the layer thickness regulating member.
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes an image carrier that carries and moves a toner image, and an exposure unit that exposes the surface of the image carrier,
The exposure means includes a light emitting unit that emits exposure light, and a duct that guides the exposure light emitted from the light emitting unit to the image carrier.
The particle adhesion suppressing member is disposed in the duct,
The image forming apparatus according to claim 6, wherein the image forming apparatus is an image forming apparatus.