JP5100106B2 - Lubricant supply device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a lubricant supply device that supplies a lubricant onto an image carrier such as a photosensitive drum, a photosensitive belt, and an intermediate transfer belt, and a process cartridge and an image forming apparatus including the lubricant supply device.

  Conventionally, in an image forming apparatus using an electrophotographic method such as a copying machine, a printer, a facsimile, or a composite machine thereof, the deposits such as untransferred toner adhered on an image carrier such as a photosensitive drum are cleaned. A technique is known that uses a lubricant supply device that supplies a lubricant onto the image carrier in order to reliably clean the device and reduce wear of the image carrier and the cleaning blade (for example, Patent Documents). 1 etc.).

Specifically, the untransferred toner remaining on the image carrier after the transfer process should be completely removed by a cleaning blade (cleaning device) that contacts the image carrier. However, when the cleaning blade deteriorates with time due to contact with the image carrier (abrasion), cleaning failure may occur due to slipping through the gap between the cleaning blade where the untransferred toner is worn and the image carrier. In particular, when an AC voltage is applied to the charging unit that charges the image carrier, the deterioration with time (wear) on the image carrier side becomes significant, and therefore the degree of cleaning failure cannot be ignored. .
Even when the cleaning blade is not deteriorated, when small toner or spherical toner is used, the toner enters a slight gap between the cleaning blade and the image carrier and eventually passes through the gap. A cleaning failure sometimes occurred.
Furthermore, if toner or an external additive or paper dust contained in the toner slips through the gap between the cleaning blade and the image carrier, it adheres to the image carrier and forms a film. There was also.

  In response to such a problem, by applying a lubricant on the image carrier, the friction coefficient on the image carrier is reduced, so that deterioration of the cleaning blade and the image carrier is reduced. Since the removability of deposits such as untransferred toner adhering to the toner is improved, it is possible to suppress the occurrence of poor cleaning and filming over time.

  Specifically, in Patent Document 1 and the like, a lubricant supply device (lubricant coating device) includes a brush roller that is in sliding contact with an image carrier (photoconductor), a solid lubricant that is in contact with the brush roller, and a solid lubricant that is supplied as a brush roller. It consists of a spring that urges toward Then, the lubricant is gradually scraped off from the solid lubricant by the brush roller rotating in a predetermined direction, and the lubricant scraped off by the brush roller is applied (supplied) to the surface of the image carrier.

  Japanese Patent Application Laid-Open No. H10-228867 and the like disclose a technique for thinning a lubricant supplied to an image carrier with a lubricant leveling blade for the purpose of supplying an appropriate amount of lubricant on the image carrier without excess or deficiency. Is disclosed. Specifically, the lubricant leveling blade is disposed downstream of the brush roller in the rotation direction of the image carrier and is in contact with the image carrier. Then, the lubricant on the image carrier supplied by the brush roller is thinned (thinned) by the lubricant leveling blade.

On the other hand, in Patent Document 2, etc., for the purpose of reducing the particle size of the lubricant supplied to the image carrier, the lubricant is supplied from the solid lubricant to the image carrier through two brush lubricant application brushes. Techniques to do this are disclosed.
In addition, Patent Document 3 and the like have a technique in which a regulating blade is applied against a rotating roller that is in sliding contact with the solid lubricant and the rotating brush for the purpose of improving the scraping property of the solid lubricant by the rotating roller. It is disclosed.

JP 2006-251751 A JP 2005-275166 A Japanese Patent No. 3307791

Since the technique disclosed in Patent Document 1 and the like described above is provided with a lubricant leveling blade that comes into contact with the image carrier, it can be expected to have some effect that the lubricant is evenly supplied onto the image carrier.
However, there are cases where the lubricant supplied onto the image carrier is not sufficiently thinned. That is, the lubricant supplied onto the image carrier by the brush roller is in the form of a powder and is not thinned by the lubricant leveling blade, but between the lubricant leveling blade and the image carrier. Sometimes slipped through. In such a case, the supply amount of the lubricant to the image carrier becomes excessive, and the charging portion is contaminated with the lubricant, causing problems such as charging failure. In particular, when the lubricant leveling blade also serves as a cleaning blade (cleaning part), untransferred toner enters between the lubricant leveling blade and the image carrier, preventing the thinning of the lubricant. Is likely to be.

  Further, since the lubricant leveling blade is in sliding contact with the image carrier, if the lubricant is not sufficiently supplied to the image carrier, the wear of the image carrier is accelerated by the lubricant leveling blade. . In particular, such a phenomenon tends to occur when a new image carrier is started to be used.

  On the other hand, the above-described technologies such as Patent Document 2 and Patent Document 3 do not thin the lubricant supplied onto the image carrier, and directly solve the problems such as contamination of the charging portion by the lubricant. Can not be resolved.

  The present invention has been made to solve the above-described problems, and a lubricant supply device, a process cartridge, and an appropriate amount of lubricant that are supplied in an evenly thin layer on an image carrier are provided. An object is to provide an image forming apparatus.

A lubricant supply device according to a first aspect of the present invention is a lubricant supply device that supplies a lubricant onto an image carrier , wherein brush bristles that are in sliding contact with a solid lubricant are provided around the lubricant supply device. A brush-like rotating member that carries a lubricant supplied from a solid lubricant, an elastic layer, and a protective layer that protects the outer peripheral surface; and the image carrier and the brush bristles of the brush-like rotating member. A roller member that is in sliding contact with the lubricant supplied from the brush-like rotating member and that supplies the lubricant onto the image carrier, abuts on the roller member at an upper position, and is carried by the roller member And a blade-like member for thinning the lubricant, and the rotation direction of the roller member is the same as the rotation direction of the image carrier .

According to a second aspect of the present invention, the lubricant supply device according to the first aspect of the present invention is configured such that the rotation direction of the brush-like rotation member is the same as the rotation direction of the roller member. It is a thing.

According to a third aspect of the present invention, in the lubricant supply device according to the first or second aspect, the solid lubricant is made of zinc stearate.

According to a fourth aspect of the present invention, there is provided the lubricant supply device according to any one of the first to third aspects, wherein the image carrier is used with respect to a cleaning unit for cleaning the image carrier. Are disposed on the downstream side in the rotation direction of the image carrier, and are disposed on the upstream side in the rotation direction of the image carrier with respect to the charging unit that charges the image carrier.

Further, the process cartridge according to the invention of claim 5, wherein, in a process cartridge which is installed detachably to the apparatus main body of the image forming apparatus, a lubricant according to any one of claims 1 to 4 The supply device and the image carrier are integrated.

According to a sixth aspect of the present invention, in the process cartridge according to the fifth aspect, the image carrier has a protective layer formed of a binder resin having a cross-linked structure and having a charge transport material. It is provided on the surface.

An image forming apparatus according to a seventh aspect of the invention includes the lubricant supply device according to any one of the first to fourth aspects and the image carrier.

According to an eighth aspect of the present invention, there is provided the image forming apparatus according to the seventh aspect , wherein the image carrier has a crosslinked structure and is formed of a binder resin having a charge transport material. On the surface.

  In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing unit (developing device) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. It is defined as a unit in which at least one of the cleaning unit (cleaning device) and the image carrier are integrated and detachably installed on the image forming apparatus main body.

  In the present invention, the lubricant is supplied from the solid lubricant to the first lubricant carrier, the lubricant is supplied from the first lubricant carrier to the second lubricant carrier, and is carried on the second lubricant carrier. After the lubricant is thinned, the lubricant is supplied onto the image carrier. Thus, it is possible to provide a lubricant supply device, a process cartridge, and an image forming apparatus in which an appropriate amount of lubricant is supplied on an image carrier in a thin layer without unevenness.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
The first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is an apparatus main body of a color copying machine as an image forming apparatus, 2 is a writing section (exposure section) that emits laser light based on input image information, and 20Y, 20M, 20C, and 20BK are colors (yellow, magenta). , Cyan, black), 21 is a photosensitive drum as an image carrier accommodated in each of the process cartridges 20Y, 20M, 20C, and 20BK, 22 is a charging unit that charges the photosensitive drum 21, and 23Y. , 23M, 23C, and 23BK are developing devices (developing units) that develop the electrostatic latent image formed on the photosensitive drum 21, and 24 is a toner image formed on the photosensitive drum 21, which is transferred to the intermediate transfer belt 27. The transfer bias roller 25 is a cleaning device (cleaning unit) that collects untransferred toner on the photosensitive drum 21. It is.

  In addition, 27 is an intermediate transfer belt on which toner images of a plurality of colors are transferred in an overlapping manner, 28 is a second transfer bias roller for transferring the toner image formed on the intermediate transfer belt 27 to the recording medium P, and 29 is an intermediate transfer belt. 27 is an intermediate transfer belt cleaning unit that collects untransferred toner, 30 is a conveyance belt that conveys a recording medium P on which a four-color toner image is transferred, and 32Y, 32M, 32C, and 32BK are developing devices 23Y and 23M. , 23C and 23BK, a toner replenishing unit for replenishing toner of each color, 51 a document conveying unit for conveying the document D to the document reading unit 55, 55 for a document reading unit for reading image information of the document D, 61 for transfer paper, etc. A paper feed unit for storing the recording medium P, and a fixing unit 66 for fixing an unfixed image on the recording medium P are shown.

Here, each of the process cartridges 20Y, 20M, 20C, and 20BK is obtained by integrating the photosensitive drum 21, the charging unit 22, the cleaning device 25, and the lubricant supply device 45, respectively. The process cartridges 20Y, 20M, 20C, and 20BK are exchanged with respect to the apparatus main body 1 in a predetermined exchange cycle. Similarly, the developing devices 23Y, 23M, 23C, and 23BK are also exchanged with respect to the apparatus main body 1 in a predetermined exchange cycle.
Image formation of each color (yellow, magenta, cyan, black) is performed on the photosensitive drum 21 in each of the process cartridges 20Y, 20M, 20C, and 20BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, the document D is transported from the document table in the direction of the arrow in the drawing by the transport roller of the document transport unit 51 and placed on the contact glass 53 of the document reading unit 55. Then, the document reading unit 55 optically reads the image information of the document D placed on the contact glass 53.

  Specifically, the document reading unit 55 scans the image of the document D on the contact glass 53 while irradiating light emitted from the illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, an image processing unit (not shown) performs color conversion processing, color correction processing, spatial frequency correction processing, and the like on the basis of RGB color separation image signals, so that yellow, magenta, cyan, and black are processed. Get color image information.

  Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. Then, laser light (exposure light) based on the image information of each color is emitted from the writing unit 2 toward the photosensitive drums 21 of the corresponding process cartridges 20Y, 20M, 20C, and 20BK.

On the other hand, the four photosensitive drums 21 rotate in the clockwise direction in FIG. First, the surface of the photosensitive drum 21 is uniformly charged at a position facing the charging unit 22 (a charging process). Thus, a charged potential is formed on the photosensitive drum 21. Thereafter, the surface of the charged photosensitive drum 21 reaches the irradiation position of each laser beam.
In the writing unit 2, laser light corresponding to the image signal is emitted from the light source corresponding to each color. The laser light is incident on the polygon mirror 3 and reflected, and then passes through the lenses 4 and 5. The laser light after passing through the lenses 4 and 5 passes through different optical paths for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  The laser beam corresponding to the yellow component is reflected by the mirrors 6 to 8 and then irradiated onto the surface of the photosensitive drum 21 of the first process cartridge 20Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 21 by the polygon mirror 3 that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 21 charged by the charging unit 22.

  Similarly, the laser beam corresponding to the magenta component is reflected by the mirrors 9 to 11 and then irradiated to the surface of the photosensitive drum 21 of the second process cartridge 20M from the left side of the paper, thereby causing an electrostatic latent image corresponding to the magenta component. An image is formed. The cyan component laser light is reflected by the mirrors 12 to 14 and then irradiated onto the surface of the photosensitive drum 212 of the third process cartridge 20C from the left side of the drawing to form a cyan component electrostatic latent image. The black component laser light is reflected by the mirror 15 and then irradiated on the surface of the photosensitive drum 21 of the fourth process cartridge 20BK from the left side of the paper, thereby forming an electrostatic latent image of black component.

Thereafter, the surface of the photosensitive drum 21 on which the electrostatic latent images of the respective colors are formed reaches positions facing the developing devices 23Y, 23M, 23C, and 23BK, respectively. Then, the respective color toners are supplied from the developing devices 23Y, 23M, 23C, and 23BK onto the photosensitive drum 21, and the latent image on the photosensitive drum 21 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 21 after the development process reaches the position facing the intermediate transfer belt 27 after passing the position facing the photosensor 41 (see FIG. 2). Here, the transfer bias roller 24 is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 27. Then, at the position of the transfer bias roller 24, the images of the respective colors formed on the photosensitive drum 21 are sequentially superimposed and transferred onto the intermediate transfer belt 27 (first transfer step).

Then, the surface of the photosensitive drum 21 after the first transfer process reaches a position facing the cleaning device 25. Then, the untransferred toner remaining on the photosensitive drum 21 is collected by the cleaning device 25 (this is a cleaning process).
Thereafter, the surface of the photosensitive drum 21 sequentially passes through the position of the lubricant supply device 45 and the position of the charge removal unit (not shown), and a series of image forming processes on the photosensitive drum 21 is completed.

On the other hand, the surface of the intermediate transfer belt 27 on which the images of the respective colors on the photosensitive drum 21 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the second transfer bias roller 28. Then, the full-color image on the intermediate transfer belt 27 is secondarily transferred onto the recording medium P at the position of the second transfer bias roller 28 (second transfer step).
Thereafter, the surface of the intermediate transfer belt 27 reaches the position of the intermediate transfer belt cleaning unit 29. Then, the untransferred toner on the intermediate transfer belt 27 is collected by the intermediate transfer belt cleaning unit 29, and a series of transfer processes on the intermediate transfer belt 27 is completed.

Here, the recording medium P at the position of the second transfer bias roller 28 is transported from the paper feeding unit 61 via the transport guide 63, the registration roller 64, and the like.
Specifically, the transfer paper P fed by the paper feed roller 62 from the paper feed unit 61 that stores the recording medium P passes through the conveyance guide 63 and is guided to the registration roller 64. The recording medium P that has reached the registration roller 64 is conveyed toward the position of the second transfer bias roller 28 in synchronization with the toner image on the intermediate transfer belt 27.

Thereafter, the recording medium P on which the full-color image is transferred is guided to the fixing unit 66 by the conveyance belt 30. In the fixing unit 66, the color image is fixed on the recording medium P at the nip between the heating roller 67 and the pressure roller 68.
Then, the recording medium P after the fixing process is discharged as an output image by the paper discharge roller 69 to the outside of the apparatus main body 1, and a series of image forming processes is completed.

Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIG.
FIG. 2 is a cross-sectional view showing the image forming unit. The four image forming units installed in the apparatus main body 1 have substantially the same structure except that the color of the toner T used in the image forming process is different. Therefore, the alphabet of reference numerals in the process cartridge, the developing device, and the toner replenishing unit. (Y, M, C, BK) is omitted for illustration.
As shown in FIG. 2, the process cartridge 20 includes a photosensitive drum 21 as an image carrier, a charging unit 22, a cleaning device 25, and a lubricant supply device 45 that are integrally stored in a case. ing.

Here, the photosensitive drum 21 as an image bearing member is a negatively charged organic photosensitive member, in which a photosensitive layer or the like is provided on a drum-shaped conductive support.
Although not shown, the photosensitive drum 21 has a conductive support as a base layer, an undercoat layer as an insulating layer, a charge generation layer and a charge transport layer as a photosensitive layer, and a protective layer (surface layer) sequentially. Are stacked.
As the conductive support (base layer) of the photosensitive drum 21, a conductive material having a volume resistance of 10 ¹⁰ Ωcm or less can be used.

The photosensitive layer of the photosensitive drum 21 can have a laminated structure or a single layer structure.
First, a case where the photosensitive layer has a laminated structure including a charge generation layer and a charge transport layer will be described.
The charge generation layer is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer. Specifically, as a charge generating substance, monoazo pigment, disazo pigment, trisazo pigment, perylene pigment, perinone pigment, quinacridone pigment, quinone condensed polycyclic compound, squalic acid dye, other phthalocyanine pigment, na A phthalocyanine pigment, an azulenium salt dye, or the like can be used. These charge generation materials can be used alone or in combination of two or more.
In the charge generation layer, the charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is dispersed on the conductive support (or below). It is formed by applying on the pulling layer and drying. As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The thickness of the charge generation layer is suitably about 0.01 to 5 μm (more preferably about 0.1 to 2 μm).

  The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. If necessary, one or more plasticizers, leveling agents, antioxidants and the like can be added. The amount of the charge transport material is suitably 20 to 300 parts by weight (preferably 40 to 150 parts by weight) with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably 25 μm or less from the viewpoint of resolution and responsiveness. The lower limit varies depending on the image forming process (particularly, charging potential), but is preferably 5 μm or more.

Next, a case where the photosensitive layer has a single layer structure will be described.
The photosensitive layer having a single-layer structure is obtained by dissolving or dispersing the above-described charge generating substance, charge transporting substance, binder resin, etc. in an appropriate solvent and coating it on a conductive support (or undercoat layer). It can be formed by drying. You may comprise from a charge generation material and binder resin, without containing a charge transport material. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, in addition to the binder resin used when the charge transport layer is formed, a binder resin used when the charge generation layer is formed may be mixed and used. Furthermore, polymer charge transport materials can also be used favorably. The amount of the charge generating material is preferably 5 to 40 parts by weight with respect to 100 parts by weight of the binder resin, and the amount of the charge transporting material is preferably 0 to 190 parts by weight (more preferably 50 to 150 parts by weight).
The photosensitive layer with a single-layer structure is a dip coating method or spray coating method in which a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transporting material using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane by a dispersing machine. It can be formed by coating with bead coat, ring coat or the like. The film thickness of the photosensitive layer is suitably about 5 to 25 μm.

  The undercoat layer of the photosensitive drum 21 is generally composed mainly of a resin. However, considering that the photosensitive layer is applied with a solvent on these resins, it has a high solvent resistance with respect to a general organic solvent. A resin is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. A fine powder pigment of metal oxide such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the undercoat layer in order to prevent moire and reduce residual potential. In addition, these undercoat layers can be formed using an appropriate solvent and coating method in the same manner as the photosensitive layer described above. The thickness of the undercoat layer is suitably about 0 to 5 μm.

The protective layer of the photosensitive drum 21 is for reducing mechanical wear on the surface of the photosensitive drum 21.
The protective layer in the first embodiment is formed of a binder resin having a crosslinked structure. The crosslinked structure is a three-dimensional network structure formed by using a reactive monomer having a plurality of crosslinking functional groups in one molecule and causing a crosslinking reaction using light or thermal energy. The binder resin having this network structure exhibits high wear resistance. From the viewpoint of electrical stability, printing durability, and life, a monomer having a charge transporting ability can be used in whole or in part as the reactive monomer. By using such a monomer, a charge transport site is formed in the network structure, and the function as a protective layer is sufficiently exhibited.

Examples of the reactive monomer having charge transporting ability include a compound containing at least one charge transporting component and a silicon atom having a hydrolyzable substituent in the same molecule, and a charge transporting component in the same molecule. A compound containing a hydroxyl group, a compound containing a charge transporting component and a carboxyl group in the same molecule, a compound containing a charge transporting component and an epoxy group in the same molecule, a charge transporting component in the same molecule And a compound containing an isocyanate group can be used. These charge transport materials having a reactive group may be used alone or in combination of two or more.
A reactive monomer having a triarylamine structure can also be used as the monomer having a charge transporting ability because of its high electrical and chemical stability and high carrier mobility.
In addition, monofunctional and bifunctional polymerizable monomers and polymerizable oligomers are used in combination for viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, low surface energy, friction coefficient reduction, and other functions. You can also. As these polymerizable monomers and oligomers, known ones can be used.

  The protective layer is formed by polymerizing or crosslinking the hole transporting compound using heat or light. When performing the polymerization reaction by heat, there are cases where the polymerization reaction proceeds only with thermal energy and a polymerization initiator is required, but in order to advance the reaction efficiently at a lower temperature, the initiator Is preferably added. In the case of polymerization by light, it is preferable to use ultraviolet light as light, but the reaction rarely proceeds only by light energy, and a photopolymerization initiator is generally used in combination. The polymerization initiator in this case mainly absorbs ultraviolet rays having a wavelength of 400 nm or less, generates active species such as radicals and ions, and initiates polymerization. In addition, it is also possible to use together the heat | fever and photoinitiator mentioned above.

The protective layer having a network structure formed in this manner has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and may become cracked if it is too thick. In such a case, the protective layer has a laminated structure, a protective layer made of a low molecular weight dispersion polymer is formed on the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure is formed on the upper layer (surface side). You may do it.
As described above, in the first embodiment, the surface of the photosensitive drum 21 is provided with the hard protective layer formed of the binder resin having a cross-linked structure and including the charge transport material. The film scraping of the photosensitive drum 21 by the cleaning blade 25a can be prevented without impairing the function as the drum 21.

  Referring to FIG. 2, the charging unit 22 is a charging roller formed by covering an outer periphery of a conductive metal core with an intermediate resistance elastic layer. A predetermined voltage is applied to the charging roller 22 from a power supply unit (not shown), thereby uniformly charging the surface of the opposing photosensitive drum 21. The charging roller 22 may be brought into contact with the photosensitive drum 21 or may be provided with a predetermined gap. In the first embodiment, a charging roller is used as the charging unit 22, but a scorotron charger can also be used as the charging unit 22.

  The developing device (developing unit) 23 mainly faces the first conveying screw 23b via the developing roller 23a facing the photosensitive drum 21, the first conveying screw 23b facing the developing roller 23a, and the partition member 23e. The second conveying screw 23c and a doctor blade 23d facing the developing roller 23a are configured. The developing roller 23a includes a magnet that is fixed inside and forms a magnetic pole on the circumferential surface of the roller, and a sleeve that rotates around the magnet. A plurality of magnetic poles are formed on the developing roller 23a (sleeve) by the magnet, and the developer G is carried on the developing roller 23a.

In the developing device 23, a two-component developer G composed of carrier C and toner T is accommodated.
As the toner T, a spherical toner having a circularity of 0.98 or more is used to improve the image quality. The “circularity” is an average circularity measured by a flow type particle image analyzer “FPIA-2000” (manufactured by Toa Medical Electronics Co., Ltd.). Specifically, 0.1 to 0.5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. Further, about 0.1 to 0.5 g of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the dispersion liquid concentration is set to 3000 to 10000 / μl in the above-described analyzer. Then, the shape and distribution of the toner are measured.

As the spherical toner, it is possible to use an irregularly shaped toner (pulverized toner) whose shape is distorted by a pulverization method that has been widely used so far, which is spheroidized by heat treatment or the like, or a toner manufactured by a polymerization method. it can.
When such a spherical toner is used, conventionally, there is a case where a slight gap between the cleaning blade 25a and the photosensitive drum 21 enters the gap and eventually passes through the gap, resulting in poor cleaning. However, in the first embodiment, since the lubricant is applied to the surface of the photosensitive drum 21 by the lubricant supplying device 45 and the toner peelability (removability) on the photosensitive drum 21 is improved, the cleaning failure is caused. Occurrence is suppressed.

  The cleaning device 25 is provided with a cleaning blade 25 a that contacts the photosensitive drum 21. The cleaning blade 25a is made of a rubber material such as urethane rubber, and is in contact with the surface of the photosensitive drum 21 at a predetermined angle and a predetermined pressure. As a result, deposits such as untransferred toner adhering to the photosensitive drum 21 are mechanically scraped and collected in the cleaning device 25. Here, as the deposits adhered to the photosensitive drum 21, in addition to the untransferred toner, paper dust generated from the recording medium P (paper), discharge products generated on the photosensitive drum 21 during discharge by the charging unit 22. And additives added to the toner.

  The lubricant supply device 45 includes a solid lubricant 46, a roller member 48 as a second lubricant carrier that contacts the photosensitive drum 21, a blade-like member 49 as a thinning means that contacts the roller member 48, solid lubricant A brush-like rotating member 47 as a first lubricant carrier that contacts the agent 46 and the roller member 48, a compression spring 50 that urges the solid lubricant 46 toward the brush-like rotating member 47, and the like. A thinned lubricant is supplied onto the photosensitive drum 21 by the lubricant supply device 45. The configuration and operation of the lubricant supply device 45 will be described in detail later.

The image forming process described above will be described in more detail with reference to FIG.
The developing roller 23a rotates in the direction of the arrow in FIG. The developer G in the developing device 23 is supplied from the toner replenishing portion 32 to the toner replenishing port by the rotation of the first transport screw 23b and the second transport screw 23c arranged with the partition member 23e interposed therebetween. It circulates in the longitudinal direction while being agitated and mixed with the toner T replenished through 23f (in the direction perpendicular to the paper surface of FIG. 2).

  Then, the toner T that is frictionally charged and adsorbed on the carrier C is carried on the developing roller 23 a together with the carrier C. The developer G carried on the developing roller 23a then reaches the position of the doctor blade 23d. The developer G on the developing roller 23a is adjusted to an appropriate amount at the position of the doctor blade 23d, and then reaches a position facing the photosensitive drum 21 (developing area).

  Thereafter, in the development area, the toner T in the developer G adheres to the electrostatic latent image formed on the surface of the photosensitive drum 21. Specifically, the toner T is latently exposed by the electric field formed by the potential difference (development potential) between the latent image potential (exposure potential) of the image area irradiated with the laser light L and the development bias applied to the development roller 23a. Adhere to the image.

  Thereafter, most of the toner T adhering to the photosensitive drum 21 in the developing process is transferred onto the intermediate transfer belt 27. The untransferred toner T remaining on the photosensitive drum 21 is collected in the cleaning device 25 by the cleaning blade 25a.

  Here, a toner replenishing unit 32 provided in the apparatus main body 1 includes a toner bottle 33 configured to be replaceable, and a toner hopper unit 34 that holds and rotates the toner bottle 33 and replenishes the developing device 23 with new toner T. And is composed of. Also, a new toner T (any one of yellow, magenta, cyan, and black) is accommodated in the toner bottle 33. In addition, a spiral protrusion is formed on the inner peripheral surface of the toner bottle 33.

  The new toner T in the toner bottle 33 is appropriately replenished into the developing device 23 from the toner replenishing port 23f as the toner T (existing toner) in the developing device 23 is consumed. . The toner T in the developing device 23 is consumed indirectly or directly by the reflective photosensor 41 facing the photosensitive drum 21 and the magnetic sensor 40 installed below the second conveying screw 23c of the developing device 23. Detected.

  Here, in the first embodiment, the toner density (TC) is controlled to be within a predetermined range. Specifically, toner replenishment is performed so that the detection results of the magnetic sensor 40 and the reflection type photosensor 41 have an output value corresponding to the above-described toner density range (the ratio of the toner T in the developer G). The toner is supplied from the unit 32 to the developing device 23 through the toner supply port 23f.

Hereinafter, the configuration and operation of the lubricant supply device 45, which is characteristic in the first embodiment, will be described in detail.
As shown in FIG. 3, the lubricant supply device 45 includes a brush-like rotating member 47 as a first lubricant carrier around which brush bristles are provided, a solid lubricant 46 in contact with the brush-like rotating member 47, solid lubrication A compression spring 50 that urges the agent 46 toward the brush-like rotating member 47, a roller member 48 as a second lubricant carrier that contacts the brush-like rotating member 47 and the photosensitive drum 21, and a thin member that contacts the roller member 48. It is composed of a blade-like member 49 as layering means.

In the brush-like rotating member 47 as the first lubricant carrier, brush hairs having a length (hair feet) in the range of 0.2 to 20 mm (preferably 0.5 to 10 mm) are planted on the base fabric. An object is wound around a metal core in a spiral shape.
When the length of the brush hair exceeds 20 mm, the brush hair falls down in a predetermined direction due to repeated rubbing with the roller member 48 over time, and the scraping property of the solid lubricant 46 and the lubricant to the roller member 48 are reduced. Supplyability will fall. On the other hand, if the length of the bristle is less than 0.2 mm, the physical contact force with respect to the solid lubricant 46 and the roller member 48 is insufficient. Therefore, it is preferable that the length of the bristle is in the above range.
Further, as the bristles of the brush-like rotating member 47, resin fibers such as nylon, rayon, acrylic, vinylon, polyester, and vinyl chloride can be used. If necessary, a conductivity imparting agent such as carbon can be added to the brush bristles made of resin fibers.

The brush-like rotating member 47 rotates so as to contact the roller member 48 rotating in the clockwise direction in FIG. 2 in the counter direction (clockwise rotation in FIG. 2). Further, the brush-like rotating member 47 is disposed so as to be in sliding contact with the solid lubricant 46 and the roller member 48, and the brush-like rotating member 47 gradually rotates to gradually remove the lubricant from the solid lubricant 46. Scrape and carry. Then, the carried lubricant is applied onto the roller member 48.
A compression spring 50 is disposed behind the solid lubricant 46 in order to eliminate contact unevenness between the brush-like rotating member 47 and the solid lubricant 46, and bias the solid lubricant 46 to the brush-like rotating member 47. is doing.

In the first embodiment, the solid lubricant 46 is formed of zinc stearate. Specifically, the solid lubricant 46 is preferably obtained by dissolving a lubricating oil additive mainly composed of zinc stearate, having no side effects due to overcoating, and having sufficient lubricity.
Zinc stearate is a typical lamellar crystal powder. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. Therefore, the surface of the photosensitive drum 21 can be made low in friction. That is, the surface of the photosensitive drum 21 can be effectively covered with a small amount of lubricant by the lamellar crystal that uniformly receives the shearing force and covers the surface of the photosensitive drum 21.

  As the solid lubricant 46, in addition to zinc stearate, stearic acid groups such as barium stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, etc. The thing which has can be used. In addition, the same fatty acid group zinc oleate, barium oleate, lead oleate, the same compound as stearic acid, zinc palmitate, barium palmitate, lead palmitate, the following compound similar to stearic acid May be used. In addition, caprylic acid, linolenic acid, corinolenic acid and the like can be used as the fatty acid group. In addition, waxes such as candelilla wax, canrunauba wax, rice wax, wax, coconut oil, beeswax, and lanolin can also be used. These easily become organic solid lubricants and have good compatibility with the toner.

  The roller member 48 as a second lubricant carrier is obtained by sequentially laminating an elastic layer 48b and a protective layer 48c on a core metal 48a. As the elastic layer 48b, a rubber material such as urethane rubber or urethane foam can be used. As the protective layer 48 c, it is preferable to use a material that has high releasability with respect to the lubricant and that is less worn by sliding contact with the blade-like member 49. Specifically, as the material of the protective layer 48c, a material in which a fluororesin such as PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin) or PTFE (tetrafluoroethylene resin) or a silicone resin is laminated is used. be able to.

The roller member 48 rotates so as to come into contact with the photosensitive drum 21 rotating in the clockwise direction in FIG. 2 in the counter direction (clockwise rotation in FIG. 2). Then, as the roller member 48 rotates, the lubricant carried on the surface thereof is applied onto the photosensitive drum 21.
Here, on the surface of the roller member 48, a blade-like member 49 as a thinning means bites into and contacts with a predetermined amount to form a nip. The blade-shaped member 49 is disposed downstream of the contact position with the brush-shaped rotation member 47 and upstream of the contact position with the photosensitive drum 21 with respect to the rotation direction of the roller member 48. Yes. As the blade-like member 49, rubber materials such as polyurethane rubber, silicone rubber, nitrile rubber, and chloroprene rubber can be used. The blade-like member 49 preferably has an elastic modulus of 20 to 80% and a plate thickness of about 1 to 6 mm.

With such a configuration, referring to FIG. 4, the lubricant S supplied onto the roller member 48 by the brush-like rotating member 47 and the lubricant SH thinned (thinned) by the thin layer blade 49 Thus, it is carried on the roller member 48.
Specifically, the powdery lubricant S stays at the contact position (nip N) between the blade-like member 49 and the roller member 48 and is thinned on the surface of the roller member 48 by the pressure of the blade-like member 49. Pass as SH. As the lubricant S applied by the brush-like rotating member 47 becomes finer, the blade SH 49 can form the lubricant SH thinned at the molecular film level on the surface of the roller member 48. The lubricant SH thus thinned (filmed) exhibits higher lubricity than a powdery lubricant.

  In the first embodiment, the blade-like rotating member 49 is arranged so as to come into contact with the rotating direction of the roller member 48 in the counter direction. As a result, a uniform pressure is applied to the lubricant at the nip N formed between the blade-like member 49 and the roller member 48, and the lubricant is reliably attached to the surface of the roller member 48 in a thin film state. Become.

  In the first embodiment, referring to FIG. 3, the blade-like member 49 is located above the roller member 48 and at a position relatively close to the contact position between the brush-like rotating member 47 and the roller member 48. It is arranged. As a result, even if a large amount of lubricant stays in the nip N of the blade-like member 49, the excess lubricant falls to the contact position between the brush-like rotating member 47 and the roller member 48. Then, the toner is supplied again onto the roller member 48. Therefore, the trouble that a large amount of the lubricant staying in the nip N falls somewhere and the apparatus becomes dirty, and the trouble that passes through the nip N and prevents the thinning of the lubricant are suppressed.

In the first embodiment, referring to FIG. 5, the rotation direction of the brush-like rotation member 47 is configured to be the same as the rotation direction of the roller member 48. With such a configuration, the lubricant is supplied from the brush-like rotating member 47 to the roller member 48 without unevenness.
Specifically, the brush bristles of the brush-like rotating member 47 are in contact with the roller member 48 with a constant biting amount, and a predetermined nip portion is formed between both members. In this nip portion, the bristle falls down in a direction different from the rotation direction of the brush-like rotating member 47. As the brush-like rotating member 47 rotates, the brush bristles that have fallen in the nip portion are eventually released on the nip portion outlet side to return to the original state. That is, the bristle is vigorously displaced in the white arrow direction (rotation direction) by the restoring force. Due to the repulsive force of the brush bristles generated at this time, the powdery lubricant S carried on the brush-like rotating member flies away from the brush-like rotating member 47 (the lubricant SM surrounded by a broken line). . Then, the flying lubricant SM adheres (applies) to the roller member 48. Thereafter, the lubricant applied to the roller member 48 enters the nip portion between the roller member 48 and the brush-like rotating member 47 again. As a result, the lubricant applied to the roller member 48 is uniformly applied on the roller member 48 by the leveling effect of the brush-like rotating member 47.

Thereafter, the lubricant SH on the roller member 48 thinned by the thin layer blade 49 is applied onto the photosensitive drum 21 as a thinned lubricant at a position where it contacts the photosensitive drum 21. It will be.
As described above, in the first embodiment, the lubricant is supplied from the solid lubricant 46 to the brush-like rotating member 47, the lubricant is supplied from the brush-like rotating member 47 to the roller member 48, and is carried on the roller member 48. The lubricant is thinned by the blade-like member 49 and then supplied onto the photosensitive drum 21. For this reason, the lubricant in a thin state is always supplied onto the photosensitive drum 21. Therefore, the lubricant to the photosensitive drum caused by slipping from the lubricant leveling blade, which has occurred in the conventional apparatus in which the lubricant is applied to the photosensitive drum 21 and then thinned by the lubricant leveling blade, is applied. Inadequate supply amount and wear of the photosensitive drum due to the lubricant leveling blade are suppressed. In the first embodiment as well, although the roller member 48 is in sliding contact with the photosensitive drum 21, the lubricant is interposed between the two members from the initial state. Little body drum wear occurs.

  FIG. 6 is a schematic diagram showing a state in which the thinned lubricant SH is supplied from the roller member 48 to the photosensitive drum 21. 6A, the surface of the roller member 48 immediately before reaching the contact position with the photosensitive drum 21 is coated with a film-like zinc stearate molecular film SH. Then, the surface of the roller member 48 coated with the molecular film reaches a nip portion having a predetermined width with the photosensitive drum 21. Here, zinc stearate forms a lamellar crystal structure when it becomes a film. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layer and becomes slippery.

In the first embodiment, the rotation direction of the roller member 48 is configured to be the same as the rotation direction of the photosensitive drum 21. Therefore, referring to FIG. 6B, the thinned lubricant SH on the roller member 48 that has reached the nip portion with the photosensitive drum 21 receives shearing force, and the crystals are divided along the layers. Is done. Then, the divided lubricant SH (zinc stearate molecular film) is transferred and adhered on the photosensitive drum 21 at the molecular film level.
Thus, even if the zinc stearate film SH adhering to the surface of the photosensitive drum 21 is a small amount, it can receive a shearing force and achieve a low friction coefficient. Therefore, the deterioration of the cleaning blade 25a and the photosensitive drum 21 can be reliably reduced, and the occurrence of cleaning failure and filming over time can be reliably suppressed.

Further, in the first embodiment, referring to FIG. 2, the lubricant supply device 45 is on the downstream side in the rotation direction of the photosensitive drum 21 with respect to the cleaning device 25, and the photosensitive member with respect to the charging unit 22. The drum 21 is disposed on the upstream side in the rotation direction. That is, the lubricant supply device 45 is disposed between the cleaning device 25 and the charging unit 22. In other words, in the image forming process performed on the photosensitive drum 21, the lubricant supplying process is performed after the cleaning process, and the charging process is performed thereafter.
Accordingly, the lubricant supply process by the lubricant supply device 45 is performed without being affected by the untransferred toner, and the lubricant can be uniformly and stably applied onto the photosensitive drum 21.

  As described above, according to the first embodiment, the lubricant is supplied from the solid lubricant 46 to the brush-like rotating member 47 (first lubricant carrier), and the brush-like rotating member 47 supplies the roller member 48 ( The lubricant is supplied to the second lubricant carrier, and the lubricant carried on the roller member 48 is thinned by the blade-like member 49 (thinning means), and then the photosensitive drum 21 (image carrier). Supplied on top. As a result, an appropriate amount of lubricant can be supplied on the photosensitive drum 21 in a thin layer without unevenness.

In the first embodiment, the lubricant supply device 45 is integrated with the photosensitive drum 21, the charging unit 22, and the cleaning unit 25 to form the process cartridge 20, and the image forming unit is made compact and maintenance workability is improved. We are trying to improve. Thus, in a compact process cartridge, a lubricant supply device having a small number of parts and a simple configuration as in the first embodiment is particularly useful.
Note that the lubricant supply device 45 may be configured so as to be replaceable in the apparatus main body 1 without being a component of the process cartridge. Even in such a case, the same effect as in the first embodiment can be obtained.
In the first embodiment, the present invention is applied to the image forming apparatus equipped with the two-component developing type developing device 23 using the two-component developer. However, the one-component developing method using the one-component developer is used. Naturally, the present invention can be applied to an image forming apparatus on which the developing device 23 is mounted.
Further, in the first embodiment, the present invention is applied to the lubricant supply device 45 that supplies the lubricant to the photosensitive drum 21 as the image carrier. However, the photosensitive belt or intermediate transfer as the image carrier is used. Naturally, the present invention can also be applied to a lubricant supply device that supplies a lubricant to the belt.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 7 is a configuration diagram illustrating the lubricant supply device according to the second embodiment, and corresponds to FIG. 3 according to the first embodiment. The second embodiment is different from the first embodiment in that the rotation direction of the brush-like rotation member 47 is opposite to the rotation direction of the roller member 48.

  Referring to FIG. 7, the lubricant supply device 45 in the present second embodiment also has a solid lubricant 46, a brush-like rotating member 47 as a first lubricant carrier, as in the first embodiment. It comprises a roller member 48 as a second lubricant carrier, a blade-like member 49 as a thinning means, a compression spring 50, and the like.

Here, the lubricant supply device 45 in the second embodiment is different from that in the first embodiment in that the brush-like rotating member 47 is in the forward direction with respect to the roller member 48 rotating in the clockwise direction in FIG. And rotate so as to come into contact with each other (the counterclockwise rotation in FIG. 7).
Accordingly, the powdery lubricant carried on the brush-like rotating member flies from the brush-like rotating member 47 by the repulsive force of the brush bristles when passing through the nip portion between the brush-like rotating member 47 and the roller member 48. Then, it adheres (applies) to the roller member 48. That is, the lubricant flying from the brush-like rotating member 47 is supplied to the roller member 48 on the downstream side in the rotation direction of the nip portion between the brush-like rotating member 47 and the roller member 48, and the lubricant on the roller member 48 becomes the blade. The thin member 49 is thinned.
Thereby, the supply efficiency (supply amount) of the lubricant from the brush-like rotating member 47 to the roller member 48 can be improved.

  As described above, also in the second embodiment, as in the first embodiment, the lubricant is supplied from the solid lubricant 46 to the brush-like rotating member 47, and from the brush-like rotating member 47 to the roller member 48. Lubricant is supplied, and the lubricant carried on the roller member 48 is thinned by the blade-like member 49 and then supplied onto the photosensitive drum 21. As a result, an appropriate amount of lubricant can be supplied on the photosensitive drum 21 in a thin layer without unevenness.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view illustrating an image forming unit in the image forming apparatus of FIG. 1. It is a block diagram which shows a lubricant supply apparatus. It is an enlarged view which shows the front-end | tip part of a blade-shaped member. It is a schematic diagram which shows the state in which a brush-like rotation member supplies a lubricant to a roller member. FIG. 4 is a schematic diagram illustrating a state in which a roller member supplies a lubricant to a photosensitive drum. It is a block diagram which shows the lubricant supply apparatus in Embodiment 2 of this invention.

Explanation of symbols

1 image forming apparatus body (apparatus body),
20, 20Y, 20M, 20C, 20BK Process cartridge,
21 photosensitive drum (image carrier), 22 charging unit,
23, 23Y, 23M, 23C, 23BK Developing device (developing unit),
25 Cleaning device (cleaning part),
25a Cleaning blade,
45 Lubricant supply device,
46 solid lubricant,
47 brush-like rotating member (first lubricant carrier),
48 roller member (second lubricant carrier),
49 Blade-like member (thinning means),
50 Compression spring, S Lubricant.

Claims (8)

A lubricant supply device for supplying a lubricant onto an image carrier,
Brush bristles that slide around the solid lubricant are provided around the brush , and carry a lubricant supplied from the solid lubricant.
An elastic layer and a protective layer for protecting the outer peripheral surface, and slidably contact the image carrier and the brush bristles of the brush-like rotating member to carry the lubricant supplied from the brush-like rotating member. A roller member to be supplied onto the image carrier,
A blade-like member that makes contact with the roller member at an upper position and thins the lubricant carried on the roller member ;
Equipped with a,
A lubricant supply device, wherein the rotation direction of the roller member is the same as the rotation direction of the image carrier . The lubricant supply device according to claim 1, wherein a rotation direction of the brush-like rotation member is configured to be the same as a rotation direction of the roller member. The lubricant supply device according to claim 1, wherein the solid lubricant is formed of zinc stearate. The image carrier is disposed on the downstream side in the rotation direction of the image carrier with respect to the cleaning unit for cleaning the image carrier, and the image carrier on the upstream side in the rotation direction with respect to the charging unit for charging the image carrier. The lubricant supply device according to any one of claims 1 to 3, wherein the lubricant supply device is disposed on the surface. A process cartridge that is detachably installed on the main body of the image forming apparatus,
5. A process cartridge in which the lubricant supply device according to claim 1 and the image carrier are integrated. 6. The process cartridge according to claim 5, wherein the image carrier is provided with a protective layer formed on a surface thereof with a binder resin having a crosslinked structure and having a charge transport material. An image forming apparatus comprising the lubricant supply device according to claim 1 and the image carrier. The image forming apparatus according to claim 7, wherein the image carrier has a protective layer formed of a binder resin having a cross-linked structure and a charge transport material on a surface thereof.

Images