JP6566681B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method using an electrophotographic recording system such as a laser printer, a copying machine, and a facsimile.

  An electrophotographic image forming apparatus includes an intermediate transfer image forming method using an intermediate transfer member. In the intermediate transfer type image forming method, the toner image formed on the image carrier is primarily transferred to the intermediate transfer member, and then the toner image on the intermediate transfer member is secondarily transferred onto the transfer material. As the intermediate transfer member, an intermediate transfer belt formed of an endless belt is widely used.

  In the intermediate transfer type image forming method, toner (secondary transfer residual toner) remains on the intermediate transfer belt after the secondary transfer step. Therefore, as a method for removing the secondary transfer residual toner on the intermediate transfer belt, a blade cleaning method is known in which the secondary transfer residual toner is physically collected by a cleaning blade disposed downstream of the secondary transfer unit. ing. Generally, an elastic body such as urethane rubber is used for the cleaning blade.

  In recent years, there has been a demand for improvement in transfer efficiency when transferring a toner image from an intermediate transfer belt to a transfer material in order to further improve image quality. Patent Document 1 proposes that a filler having a particle size smaller than that of the toner is embedded on the surface of the intermediate transfer belt to improve surface properties, so that the toner hardly remains on the intermediate transfer belt and the transfer efficiency is improved. Has been. Patent Document 2 proposes an intermediate transfer belt in which toner is hardly left on the intermediate transfer belt and the transfer efficiency is improved by defining the surface roughness of the intermediate transfer belt.

JP 2009-75154 A JP 2004-240176 A

  At present, the image forming apparatus is required to have further durability, and the intermediate transfer belt using the blade cleaning method needs to be further improved in durability by repeated use.

  As a result of the study by the present inventors, the method of adding a filler to the surface of the intermediate transfer belt of Patent Document 1 has a problem in terms of wear of the cleaning blade due to repeated use. When the protrusion shape of the filler is scattered on the surface of the intermediate transfer belt, the edge portion of the cleaning blade starts to be gradually worn from the contact point with the protrusion shape by repeated use. As a result, there is a concern that the edge portion of the cleaning blade is worn unevenly or the edge portion of the cleaning blade is chipped, and toner slips out (cleaning failure) from that point.

  Further, since the intermediate transfer belt that defines the surface roughness value of Patent Document 2 has a protrusion shape on the surface, there is a concern that the wear amount of the edge portion of the cleaning blade increases as in Patent Document 1.

  These blade cleaning type intermediate transfer belts have room for improvement in reducing the wear of the cleaning blade in long-term use.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method including an intermediate transfer belt that can improve both the efficiency of toner transfer from the intermediate transfer belt to the transfer material and the suppression of the amount of wear of the cleaning blade in repeated use over a long period of time. For the purpose.

The present invention
A charging step of charging the image bearing member with a charging means;
An exposure step of exposing the charged image carrier to form an electrostatic latent image;
A developing step of developing the electrostatic latent image with toner to form a toner image on the image carrier;
A transfer step of transferring the toner image to a transfer material via an intermediate transfer belt;
A fixing step of fixing the toner image on the transfer material, and a cleaning step of removing residual transfer toner remaining on the intermediate transfer belt with a cleaning blade;
An image forming method comprising:
The surface of the intermediate transfer belt has a groove shape in a direction crossing the cleaning blade,
The in-plane average roughness of the surface of the intermediate transfer belt in the toner weight average particle size square (D4 μm × D4 μm) is 10 nm or more and 30 nm or less,
The ten-point average roughness Rzjis of the surface of the intermediate transfer belt in the direction perpendicular to the rotation direction of the intermediate transfer belt is 0.26 μm or more and 0.67 μm or less,
The toner has toner particles containing a binder resin, a colorant and a release agent;
The toner particles are toner particles produced by a suspension polymerization method;
The aspect ratio of the toner measured by a flow type particle image measuring device having an image processing resolution of 512 × 512 pixels (0.19 μm × 0.19 μm per pixel) is 0.850 or more,
The glass transition point Tg (T) of the toner is 50.0 ° C. or higher and 70.0 ° C. or lower,
The ratio of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm to toner particles having an equivalent circle diameter of 0.25 μm or more and less than 39.5 μm of the toner is 1.0 number% or more and 15.0 numbers % Or less,
The present invention relates to an image forming method, wherein the toner satisfies the relationship of the following formula (1).
Tg (N) −Tg (T) ≧ 1.5 Formula (1)
(In formula (1), Tg (N) represents the glass transition point of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm of the toner.)

  According to the present invention, there is provided an image forming method provided with an intermediate transfer belt that achieves both improvement in toner transfer efficiency from the intermediate transfer belt to the transfer material and suppression of the amount of wear of the cleaning blade in repeated use over a long period of time. be able to.

1 is a schematic cross-sectional view of an example of an image forming apparatus having an intermediate transfer belt. FIG. 3 is a diagram for explaining a belt cleaning method for an intermediate transfer belt (a, b). Schematic views (a) and (b) showing a cross section of the intermediate transfer belt and a schematic view (c) of the intermediate transfer belt as viewed from above are shown. The enlarged view (a, b, c) of the surface layer of an intermediate transfer belt is shown. The enlarged view (a, b, c, d) of the surface layer of the intermediate transfer belt and the cleaning blade nip portion is shown. It is a figure which shows the other aspect of the intermediate transfer belt which concerns on this invention.

Hereinafter, the image forming apparatus, the intermediate transfer member, and the method of manufacturing the intermediate transfer member according to the present invention will be described in more detail with reference to the drawings.

<Image forming apparatus>
First, a color image forming apparatus using four color toners will be described with reference to FIG. In the form shown in FIG. 1, the first station is yellow (Y), the second station is magenta (M), the third station is cyan (C), and the fourth station is black (K). In the first station, reference numeral 1a denotes a photosensitive drum as an image carrier, which includes a charging roller 2a as a charging unit, a cleaning unit 3a for cleaning residual toner remaining on the photosensitive drum 1a, and a developing unit 8a as a developing unit. Have. The developing unit 8a includes a developing sleeve 4a, a non-magnetic one-component developer (also referred to as toner) 5a, and a developer application blade 7a. The above-described 1a to 8a are an integrated process cartridge 9a. The exposure means (not shown) is composed of a scanner unit that scans laser light with a polygon mirror, and irradiates the photosensitive drum 1a with a scanning beam 12a modulated based on an image signal. The process cartridges 9b to 9d in the second to fourth stations have the same configuration as the process cartridge 9a in the first station.

  Next, an image forming operation will be described. When the image forming operation starts, the photosensitive drums 1a to 1d, the intermediate transfer belt 13 and the like start to rotate in the arrow direction at a predetermined process speed. First, the operation of the first station will be described. First, the photosensitive drum 1a is uniformly charged to a negative polarity by a voltage supplied from a power source (not shown) to the charging roller 2a. Subsequently, an electrostatic latent image according to the image information is formed on the photosensitive drum 1a by a scanning beam 12a from an exposure unit (not shown). The toner 5a in the developing unit 8a is negatively charged by the developer application blade 7a and applied to the developing sleeve 4a. A voltage is supplied to the developing sleeve 4a from a developing voltage power source (not shown). When the electrostatic latent image formed on the photosensitive drum 1a reaches the developing sleeve 4a facing portion, the electrostatic latent image on the photosensitive drum 1a is visualized by negative toner, and the first color (on the photosensitive drum 1a ( In FIG. 1, a toner image Y) is formed. The second to fourth stations have the same configuration as the first station.

  On the other hand, the intermediate transfer belt 13 which is a toner image carrier is disposed so as to abut against all four photosensitive drums 1a to 1d. The intermediate transfer belt 13 is supported by three rollers, a support roller 24, a drive roller 14, and a tension roller 15, which are positioned opposite to the secondary transfer roller 25, so that appropriate tension is maintained. . By driving the drive roller 14, the intermediate transfer belt 13 moves in the forward direction (direction of arrow a) at substantially the same speed with respect to the photosensitive drums 1a to 1d. The primary transfer roller 10a is urged with a predetermined pressure to the photosensitive drum 1a via the intermediate transfer belt 13 to form a primary transfer nip.

  Electrostatic latent images are formed on the respective photosensitive drums 1a to 1d by exposure with a delay at a constant timing in accordance with the distance between the primary transfer nips for each color. Then, by applying a voltage having a polarity opposite to that of the toner from the primary transfer power sources 22a to 22d to each of the primary transfer rollers 10a to 10d, the toner images are sequentially transferred to the intermediate transfer belt 13, and the multiple toner is transferred onto the intermediate transfer belt 13. An image is formed.

  Thereafter, the transfer material S loaded on a recording medium cassette (not shown) is picked up by a paper supply roller (not shown) in accordance with the formation of an electrostatic latent image by exposure, and a registration roller 18 by a conveyance roller (not shown). It is conveyed to. The transfer material S is conveyed by the registration roller 18 to a secondary transfer nip portion formed by the intermediate transfer belt 13 and the secondary transfer roller 25 in synchronization with the toner image on the intermediate transfer belt 13. Thereafter, the secondary transfer power supply 26 applies a voltage having a polarity opposite to that of the toner to the secondary transfer roller 25, and the four-color multiple toner images carried on the intermediate transfer belt 13 are collectively put on the transfer material S. Secondary transferred.

In this embodiment, the primary transfer rollers 10a to 10d are configured by covering a core metal of a nickel-plated steel rod having an outer diameter of 5 mm with a foaming elastic body so as to have an outer diameter of 14 mm. If the primary transfer roller resistance is in the range of 10 ³ to 10 ⁷ Ω, good image formation can be performed. The secondary transfer roller 25 is configured by coating a core metal of a nickel-plated steel rod having an outer diameter of 8 mm with a foaming elastic body so as to have an outer diameter of 16 mm. If the secondary transfer roller resistance is in the range of 10 ⁷ to 10 ⁹ Ω, good image formation can be performed. The drive roller 14 used had an outer diameter of 26.3 mm covered with silicone rubber having a resistance of 10 ⁵ Ω and a wall thickness of 0.085 mm in which carbon was dispersed in an aluminum core. The tension roller 15 as a stretching member applies a tension of 49 N on one side and a total pressure of 98 N to the intermediate transfer belt 13 using an aluminum metal rod having an outer diameter of 24 mm. As the support roller 24 positioned opposite the secondary transfer roller 25, a support roller 24 having an outer diameter of 18 mm coated with EPDM rubber having a resistance of 10 ⁵ Ω and a thickness of 1 mm in which carbon is dispersed as a conductive agent in an aluminum core metal was used. The transfer material S is conveyed to the fixing unit 19 after the completion of the secondary transfer, and is fixed to the toner image, and is discharged out of the image forming apparatus as an image formed product.

<Blade cleaning device for intermediate transfer belt>
Next, cleaning of the intermediate transfer belt in the color image forming apparatus will be described. FIG. 2A schematically shows a portion where the cleaning unit 27 and the intermediate transfer belt 13 are in contact with each other. The cleaning means 27 is an elastic cleaning blade 28 made of urethane rubber. The cleaning blade 28 has a structure in which a rubber part 29 made of polyurethane rubber is bonded to a sheet metal part 30 made of a plated steel plate, and the thickness of the rubber part 29 is 2 mm, for example. The rubber part 29 had a hardness of 77 ° according to JIS K6253 standard. The cleaning blade 28 is configured to swing, and the cleaning shaft is fixed around the swing shaft 32 by fixing the swing shaft 32 to an intermediate transfer belt unit (not shown) and pressurizing the sheet metal 30 with a pressure spring 31. 28 moves. A tension roller 15 is disposed inside the intermediate transfer belt 13 so as to face the rubber portion 29. The cleaning blade 28 contacts the tension roller 15 in the counter direction with respect to the drive rotation direction of the intermediate transfer belt 13, and scrapes off the transfer residual toner at the nip portion 33 (FIG. 2B). In this way, after the secondary transfer is completed, the transfer residual toner remaining on the intermediate transfer belt 13 is removed and collected from the surface by the intermediate transfer belt cleaning unit 27.

The mounting position of the cleaning blade 28 is set at a set angle θ (angle formed by the tangent to the tension roller 15 at the intersection of the intermediate transfer belt 13 and the cleaning blade rubber portion 29 and the cleaning blade rubber portion 29), and the intrusion amount δ. The length in the thickness direction in which the cleaning blade rubber part 29 overlaps the tension roller 15 is 1.5 mm, and the contact pressure of the cleaning blade 28 is 0.6 N / cm ² . By setting to this setting position, the color image forming apparatus of the present embodiment suppresses turning-up and slipping noise of the cleaning blade in a high-temperature and high-humidity environment (temperature 30 ° C./humidity 80%), and provides good cleaning performance. Can be obtained. Also, good cleaning performance can be obtained without causing poor cleaning in a low temperature and low humidity environment (temperature 15 ° C./humidity 10%).

The above cleaning configuration is appropriately selected according to the intermediate transfer belt material. Preferably, the material of the cleaning blade rubber portion 29 is polyurethane rubber. Further, the hardness of the cleaning blade rubber part 29 is preferably in the range of 70 degrees to 80 degrees in accordance with JIS K6253 standard. Further, the contact pressure of the cleaning blade 28 against the intermediate transfer belt, 0.4 N / cm ² or more 0.8N / cm ² or less.

<Configuration of intermediate transfer belt>
Next, the configuration of the intermediate transfer belt in the present embodiment will be described. The intermediate transfer belt 13 is preferably an endless film-like member composed of two or more layers having a base layer and a surface layer. FIG. 3A is an enlarged partial cross-sectional view in the direction orthogonal to the rotational driving direction in the vicinity of the surface layer of the intermediate transfer belt 13. The base layer 101 is a layer having a thickness of 70 μm in which carbon black is dispersed as a resistance adjusting agent in a polyethylene naphthalate resin. The surface layer 102 is a layer having a thickness of 3 μm in which antimony-doped zinc oxide particles 105 are dispersed as a resistance adjusting agent in an acrylic copolymer 103 and polytetrafluoroethylene (hereinafter referred to as PTFE) particles 104 are added. As shown in FIG. 3 (a), the PTFE particles 104 added to the surface layer 102 are deposited on the outermost surface and form a protrusion shape in a partially exposed state, and are also dispersed in the surface layer. Existing.

  Further, the surface of the surface layer 102 is subjected to a surface processing treatment to have a groove shape. This groove shape is a direction crossing the cleaning blade. FIG. 3B shows a cross-sectional view of the groove shape formed in the surface layer 102. The width of the groove shape (groove width 111) is preferably less than half the weight average particle diameter (D4) of the toner. In FIG. 3B, the groove width 111 of the groove shape 110 is 2 μm. The groove depth 112 is 1 μm. The pitch 113 of the groove shape 110 is 10 to 20 μm. Since the thickness of the surface layer 102 is 3 μm, the groove shape 110 does not reach the base layer 101 and exists only in the surface layer 102. FIG. 3C shows the intermediate transfer belt 13 as viewed from above. The groove shape 110 exists over the entire circumference of the intermediate transfer belt 13 along the rotational driving direction of the intermediate transfer belt 13. In FIG. 3C, the groove shape 110 is in a positional relationship perpendicular to the contact portion in the longitudinal direction of the cleaning blade rubber portion 29.

When the volume resistivity of the intermediate transfer belt 13 is in the range of 10 ⁹ to 10 ¹² Ω · cm, using Hiresta UP MCP-HT450 (manufactured by Mitsubishi Chemical Corporation), good image formation can be performed.

<Method for producing intermediate transfer belt>
Next, a method for producing the intermediate transfer belt 13 will be described. The surface layer of the intermediate transfer belt preferably contains a curable resin. As the curable resin, an acrylic copolymer is preferable.

  First, as a material used for the base layer 101 of the intermediate transfer belt 13 of the present invention, for example, polycarbonate, polyvinylidene fluoride (PVDF), polyethylene, polypropylene, polymethylpentene-1, polystyrene, polyamide, polysulfone, polyarylate, polyethylene Examples include thermoplastic resins such as terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyphenylene sulfide, polyethersulfone, polyethernitrile, thermoplastic polyimide, polyetheretherketone, thermotropic liquid crystal polymer, and polyamic acid. It is done. Two or more of these can be mixed and used. In addition, the base material 101 of the intermediate transfer belt 13 can be obtained by melt-kneading a conductive material or the like in these thermoplastic resins and then appropriately selecting a molding method such as inflation molding, cylindrical extrusion molding, or blow molding. .

  Next, a method for manufacturing the surface layer 102 will be described. From the viewpoint of improving the surface hardness and durability (wear resistance) of the intermediate transfer belt, the surface layer preferably contains a curable material. Preferably, it is a curable resin. The curable resin is obtained by curing a composition containing a curable monomer and / or oligomer component. Examples of the curing means include curing by irradiation with energy rays such as ultraviolet rays and electron beams, and curing by heat. Curing by irradiation with ultraviolet rays or electron beams is preferable.

  Examples of the curable resin include melamine resin, urethane resin, alkyd resin, acrylic resin, and fluorine-based curable resin (fluorine-containing curable resin). Among the curable materials, examples of inorganic materials include alkoxysilane / alkoxyzirconium-based materials and silicate-based materials. Among the curable materials, organic / inorganic hybrid materials include inorganic fine particle dispersed organic polymer materials, inorganic fine particle dispersed organoalkoxysilane materials, acrylic silicon materials, organoalkoxysilane materials, and the like.

  From the viewpoint of strength such as wear resistance and crack resistance of the surface layer 102 of the intermediate transfer belt 13, an acrylic copolymer obtained by curing an unsaturated double bond-containing acrylic copolymer is preferable among curable resins. . The unsaturated double bond-containing acrylic copolymer is available, for example, as lucifural (trade name, manufactured by Nippon Paint Co., Ltd.), which is an acrylic ultraviolet curable hard coat material.

Further, a conductive material (conductive filler, resistance adjusting agent) 105 may be added to the surface layer 102 for the purpose of adjusting electric resistance. As the conductive material, an electron conductive material or an ion conductive material can be used. Examples of the electronic conductive material include particulate, fibrous or flaky carbon-based conductive fillers such as carbon black, PAN-based carbon fiber, and expanded graphite pulverized product. Also, for example, particulate, fibrous or flaky metallic conductive fillers such as silver, nickel, copper, zinc, aluminum, stainless steel and iron can be mentioned. Examples thereof include particulate metal oxide conductive fillers such as zinc antimonate, antimony-doped tin oxide, antimony-doped zinc oxide, tin-doped indium oxide, and aluminum-doped zinc oxide. Examples of the ion conductive material include an ionic liquid, a conductive oligomer, and a quaternary ammonium salt. One or more of these conductive materials may be appropriately selected, and an electronic conductive material and an ion conductive material may be mixed and used. These conductive materials may be used alone or in combination of two or more. Among these, a particulate metal oxide based conductive filler of submicron or less is preferable, and antimony-doped zinc oxide particles and the like can be mentioned.

  Further, a solid lubricant 104 may be added to the surface layer 102. Examples of solid lubricants include PTFE resin powder, ethylene trifluoride chloride resin powder, ethylene tetrafluoride hexafluoropropylene resin powder, vinyl fluoride resin powder, vinylidene fluoride resin powder, difluoride difluoride. It can be appropriately selected from fluorine-containing particles such as ethylene chloride resin powder, fluorinated graphite, and copolymers thereof. Moreover, silicone resin particles, silica particles, molybdenum disulfide powder, and the like may be used. Among these, polytetrafluoroethylene) PTFE) resin particles are preferable because they have a low coefficient of friction on the surface of the particles and can reduce wear of other members in contact with the surface layer 102 of the intermediate transfer belt.

  An outline of an example of a method for manufacturing the surface layer 102 is as follows. Antimony-doped zinc oxide as a conductive material and PTFE particles as a solid lubricant are mixed in an unsaturated double bond-containing acrylic copolymer, and dispersed and mixed with a high-pressure emulsifying disperser. Make it. Moreover, as a method of forming the surface layer 102 on the base layer 101, a normal coating method, for example, a dip coat, a spray coat, a roll coat, a spin coat etc. can be mentioned. The surface layer 102 having a desired film thickness can be obtained by appropriately selecting from these methods.

  A groove shape 110 is formed on the surface layer 102 of the intermediate transfer belt obtained by the above method. The groove shape 110 can be formed by bringing the wrapping film into contact with the surface layer 102 and rotating the intermediate transfer belt 13 or by rubbing the wrapping film in the rotation direction of the intermediate transfer belt 13. . Further, the method for imparting a desired surface form to the surface layer 102 of the intermediate transfer belt 13 is not limited to processing using a wrapping film. For example, a method of imparting a desired surface form to the surface of the base layer 101 before coating the surface layer 102, post-processing using a mold or nanoimprint technology, and the like can be mentioned. A more detailed example of the processing method will be described later.

<Relationship between surface layer of intermediate transfer belt and transfer efficiency>
In order to improve the transfer efficiency when transferring the toner on the intermediate transfer belt 13 to the transfer material S, the surface layer 102 of the intermediate transfer belt needs to be smooth. Specifically, the in-plane average roughness of the surface of the intermediate transfer belt in the toner weight average particle diameter square (D4 μm × D4 μm) is 10 nm or more and 30 nm or less.

  When the in-plane average roughness of the surface layer 102 is less than 10 nm as shown in FIG. 4A and the ratio of the smooth portion is dominant, the contact opportunity (contact area) between the toner and the surface layer 102 is small. Is mainly in point contact. As a result, the physical adhesive force acting between the toner and the surface layer 102 is weak and the releasability of the toner is improved, so that the transfer efficiency is improved. The in-plane average roughness represents the surface roughness (or surface smoothness) in a minute region, and the measurement method will be described later.

  Further, as shown in FIG. 4B, when the in-plane average roughness of the surface layer 102 is larger than 30 nm and there is no smooth portion, there are many opportunities for contact between the toner and the surface layer (contact area). Multi-point contact. As a result, the physical adhesion acting between the toner and the surface layer is strong and the releasability of the toner is deteriorated, so that the transfer efficiency is lowered.

  As shown in FIG. 4C, the surface layer 102 in which the in-plane average roughness of the surface of the intermediate transfer belt is 10 nm or more and 30 nm or less and the groove 110 having the groove width 111 less than half the weight average particle diameter of the toner is formed. In the case of, for example, a spherical toner, the toner may exist on the groove. The toner on the groove exists in two-point contact with the surface layer 102 without being buried in the groove shape because the groove width 111 is smaller than the particle diameter of the toner. For this reason, compared to the surface layer 102 (FIG. 4B) where no smooth portion exists, the physical adhesive force acting between the toner and the surface layer 102 is weak, and sufficient transfer efficiency is maintained. Therefore, it is possible to suppress the wear of the cleaning blade as will be described later.

<Relationship between surface layer of intermediate transfer belt and abrasion of cleaning blade>
In order to satisfy the cleaning performance of the intermediate transfer belt 13, the surface layer 102 of the intermediate transfer belt needs to have an appropriate roughness.

  The groove shape 110 formed on the surface layer 102 of the intermediate transfer belt intersects the longitudinal contact portion of the cleaning blade rubber portion 29. FIG. 5A shows the vicinity of the nip portion between the cleaning blade rubber portion 29 and the intermediate transfer belt surface layer 102. Since the cleaning blade rubber portion 29 does not contact the groove shape, the contact area with the intermediate transfer belt 13 at the nip portion is reduced. As a result, the frictional force at the nip portion during rotation of the intermediate transfer belt 13 is reduced, and the wear of the cleaning blade is suppressed. Further, it is more preferable that the groove width 111 of the groove shape 110 is less than the weight average particle diameter of the toner, so that the toner enters the groove shape and is prevented from slipping through the cleaning blade 21. On the other hand, as shown in FIG. 5B, when the surface layer 102 has no groove shape, the cleaning blade rubber portion 29 is in close contact with the intermediate transfer belt 12 at the nip portion 23. For this reason, the frictional force in the nip portion during the rotation of the intermediate transfer belt 13 is large, and the blade wears with repeated use, resulting in poor cleaning. As shown in FIG. 5C, when the surface layer 102 is provided with a random uneven shape, the cleaning blade rubber portion 29 comes into contact with the convex portion of the surface layer 102 at the nip portion. Therefore, in the nip portion, the cleaning blade rubber portion 29 concentrates pressure on the contact region portion with the surface layer 102, and the frictional force at the contact region portion increases. As a result, blade wear locally progresses due to repeated use, and uneven wear and chipping occur, resulting in poor cleaning. Further, as shown in FIG. 5 (d), in the case of the surface layer 102 having a convex shape due to the addition of a filler or the like, the cleaning blade rubber portion 29 is also a convex portion of the surface layer 102 at the nip portion as in FIG. 5 (c). Contact with. Therefore, the cleaning blade rubber portion 29 that comes into contact with the convex portion of the surface layer 102 is locally worn by repeated use, causing uneven wear and chipping, resulting in poor cleaning.

  In addition, when the in-plane average roughness of the surface layer 102 is less than 10 nm, the contact area between the cleaning blade and the intermediate transfer belt is increased, and the cleaning blade is likely to be worn.

  Here, the ratio of the contact area of the cleaning blade to the total surface area of the intermediate transfer belt within the range of the cleaning blade in the direction substantially orthogonal to the conveyance direction of the intermediate transfer belt (in the region where the blade and the belt face each other) Contact area ratio. The contact area ratio of the cleaning blade is preferably 80% or more and 97% or less. Within this range, good cleaning performance can be obtained due to the frictional force reduction effect.

  Further, the ten-point average roughness Rzjis of the surface of the intermediate transfer belt in the direction orthogonal to the rotation direction of the intermediate transfer belt is 0.26 μm or more and 0.67 μm or less. By making it within the above range, it is possible to effectively achieve both transferability and suppression of wear of the cleaning blade.

As mentioned above, although this invention was demonstrated according to specific embodiment, this invention is not limited to the above-mentioned embodiment.

  For example, as shown in FIG. 6, even if the intermediate transfer belt is not substantially parallel to the moving direction of the surface of the intermediate transfer belt but has a certain angle and forms a groove shape intersecting the cleaning blade. The same effect can be obtained.

  In the case of a single-layer intermediate transfer belt, a similar effect can be obtained by forming a specific groove shape on the surface of the intermediate transfer belt. In addition, the configuration in which the intermediate transfer member is composed of a plurality of layers is not limited to two layers, and the layer corresponding to the base layer of the above-described embodiment is composed of a plurality of layers or corresponds to the base layer of the above-described examples. One or a plurality of layers may be provided under the layer to be performed.

  Further, the image forming apparatus is not limited to an inline type. For example, a plurality of developing devices are provided for one photoconductor, and toner images sequentially formed on the photoconductor are sequentially primary-transferred onto the intermediate transfer belt and then superimposed on the intermediate transfer belt. An image forming apparatus of a type that secondarily transfers the combined toner image onto a transfer material may be used.

<Configuration of toner>
The toner used in the present invention has toner particles containing a binder resin, a colorant, and a release agent, and has the following four characteristics. First, the aspect ratio of the toner measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.19 μm × 0.19 μm per pixel) is 0.850 or more. Second, the glass transition point Tg (T) of the toner is 50.0 ° C. or higher and 70.0 ° C. or lower. Third, the ratio of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm to toner particles having an equivalent circle diameter of 0.25 μm or more and less than 39.5 μm is 1.0% by number or more and 15%. 0.0% or less. Fourth, the toner satisfies the relationship of the following formula (1).
Tg (N) −Tg (T) ≧ 1.5 Formula (1)
In the formula (1), Tg (N) represents a glass transition point of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm of the toner.

  By using a toner having a high aspect ratio of 0.850 or more, the toner can effectively increase transfer efficiency in an intermediate transfer belt having surface characteristics with low in-plane average roughness. it can. The present inventors consider this reason as follows.

  That is, when the toner has a high aspect ratio, the toner is charged negatively by the developer application blade, and the toner can be more uniformly charged when applied to the developing sleeve. It is presumed that by making the toner charge uniform, stable transfer is possible when the toner is transferred from the intermediate transfer belt to the transfer material. Further, when the aspect ratio of the toner is high, the circularity of the toner tends to increase. Therefore, it is expected that the contact area between the toner and the intermediate transfer belt tends to be small.

  When the glass transition point Tg (T) of the toner is 50.0 ° C. or higher and 70.0 ° C. or lower, both low-temperature fixability and storage stability can be achieved.

  The toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm with respect to toner particles having an equivalent circle diameter of 0.25 μm or more and less than 39.5 μm mean fine powder contained in the toner. The toner contains fine powder of 1.0% to 15.0% by weight, and the glass transition point Tg (N) of the fine powder is 1.5 ° C. or more higher than the glass transition point Tg (T) of the toner. As a result, the wear amount of the cleaning blade of the transfer belt can be effectively suppressed. It is expected that when the intermediate transfer belt is driven to rotate, fine powder is present in the nip portion with the cleaning blade, thereby providing lubricity and reducing the generated frictional force. At that time, by controlling the amount of fine powder to 15.0% by number or less with respect to the whole toner particles, it is possible to prevent the toner from slipping through the cleaning blade. Further, since the glass transition point Tg (N) of the fine powder is higher by 1.5 ° C. or more than the glass transition point Tg (T) of the toner, the fine powder is prevented from adhering to and fused to the cleaning blade. Wear can be suppressed.

  As a method for making the glass transition point Tg (N) of the fine powder higher than the glass transition point Tg (T) of the toner, there is a method of adding desired particles into the toner. In the present invention, in a method for producing toner by granulating in an aqueous medium, which is a preferable production method, adjusting the amount and addition method of a dispersion stabilizer for stabilizing droplets in the aqueous medium. There is a way to control.

<Measuring method of glass transition point Tg (T), Tg (N)>
The glass transition points Tg (T) and Tg (N) can be measured using a differential scanning calorimeter (DSC). The DSC is measured according to ASTM D3418-82 using, for example, “Q1000” (manufactured by TA Instruments). The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, about 2 mg of a sample as a specimen is precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed in the following sequence. In the toner of the present invention, a modulated mode is used. Further, the glass transition point (Tg) here is determined by the midpoint method. In order to measure Tg (N), particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm can be obtained using an airflow classifier. There is also a method for obtaining a sample by the following methods (1) to (5) using a centrifugal separator. The above two methods may be combined.
(1) 30 ml of RO water in a 50 ml centrifuge tube,
6ml of "Contaminone N" (Nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for cleaning precision measuring instruments with pH 7 consisting of organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersant After charging, about 1 g of toner is introduced.
(2) The tube produced in the above (1) is set on a shaker, and shaken under conditions of a shaking number of 6 s ⁻¹ and a shaking time of 20 minutes.
(3) The shaken solution prepared in (2) above is placed in a glass tube for a 50 ml swing rotor, and centrifuged in a centrifuge at a rotation speed of 58 s ⁻¹ and a rotation time of 30 min to obtain toner and fine powder. And are separated.
(4) The toner is deposited on the lower layer. Fine powder is present in the supernatant along with the RO water.
(5) After filtering the supernatant liquid of the above (4) with a vacuum filter, it is dried with a dryer for 1 hour or more to obtain a fine powder.

<Aspect ratio and method for measuring the number of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm>
The aspect ratio of the toner was measured with a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during calibration work.

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. About 0.2 ml of a diluted solution obtained by diluting “Contaminone N” (manufactured by Wako Pure Chemical Industries, Ltd.) with ion-exchanged water about 3 times by mass as a dispersant is added thereto. Further, about 0.04 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a measurement dispersion. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by Vervocrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. A predetermined amount of ion-exchanged water is placed in the water tank, and about 2 ml of the contamination N is added to the water tank.

  For the measurement, a flow type particle image analyzer equipped with “LUCPLFLN” (20 × magnification, numerical aperture of 0.40) as an objective lens is used, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. used. The dispersion prepared in accordance with the above procedure is introduced into a flow particle image analyzer, and 2000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis was set to 85%, the analysis particle diameter was limited to a circle equivalent diameter of 1.977 μm or more and less than 39.54 μm, and the toner aspect ratio was determined.

  The number of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm is calculated by calculating a ratio of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm in the measurement result of the 2000 toner particles. Can be done.

  In measurement, automatic focus adjustment is performed using standard latex particles (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In this example, a flow type particle image analyzer which has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. Measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to a circle equivalent diameter of 1.977 μm or more and less than 39.54 μm.

  The measurement principle of the flow-type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) is to capture flowing particles as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with stroboscopic light with a nucleus for 1/60 second, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is captured by a CCD camera, and the captured image is subjected to image processing at an image processing resolution of 512 × 512 (0.19 μm × 0.19 μm per pixel), and the contour of each particle image is extracted, The projected area S, the peripheral length L, and the like are measured. The aspect ratio is obtained from the following equation by measuring the short diameter and long diameter of the toner particles.

Aspect ratio = minor axis / major axis After calculating the aspect ratio of each particle, the arithmetic average value of the obtained aspect ratios is calculated, and this value is taken as the aspect ratio of the toner.

<Method for Measuring Toner Weight Average Particle Size (D4)>
The weight average particle diameter (D4) of the toner is calculated as follows. As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  On the “Change Standard Measurement Method (SOMME)” screen of the dedicated software, set the total count in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. About 0.3 ml of a diluted solution obtained by diluting “Contaminone N” (manufactured by Wako Pure Chemical Industries, Ltd.) with ion-exchanged water about 3 times by mass as a dispersant is added thereto.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetra 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set by the dedicated software is the weight average particle diameter (D4).

  The toner particles of the present invention are preferably produced by a production method of granulating in an aqueous medium such as suspension polymerization or suspension granulation. Among these, the suspension polymerization method capable of easily producing toner particles having a core / shell structure is suitable in terms of achieving both low-temperature fixability and storage stability.

  The toner of the present invention preferably has a weight average particle diameter (D4) of 3.0 to 8.0 μm.

  The weight average particle diameter (D4) of the toner can be satisfied by adjusting the particle size in a particle size adjusting process such as air classification and sieving at the time of toner production. In the case of a polymerized toner which is a preferred form of the present invention, it can be adjusted by the amount of the dispersion stabilizer charged.

  Examples of the binder resin used in the toner include polystyrene; homopolymers of styrene substitution products such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, and styrene. -Vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer Styrene copolymers such as polymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers Acrylic resin; methacrylic tree ; Polyvinyl acetate; silicone resins; polyester resins; polyamide resin; furan resins, epoxy resins, xylene resins. These resins are used alone or in combination.

  The comonomer for the styrene monomer of the styrene copolymer includes acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, doditer acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methacrylic acid. Monocarboxylic acid having a double bond such as methyl acid, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid, butyl maleate, methyl maleate, maleate Dicarboxylic acids having a double bond such as dimethyl acid and its substitutes; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene-based olefins such as ethylene, propylene and butylene; Sulfonyl methyl ketone, vinyl ketones such as vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether. These vinyl monomers are used alone or in combination of two or more.

  As the polymerizable monomer used when the toner is produced by the polymerization method, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used. Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p A styrene derivative such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl accelerator Acrylic polymerizable monomers such as N-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Body; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n- Octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl meta Methacrylic polymerizable monomers such as relate and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate and vinyl formate; vinylmethyl And vinyl ethers such as ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, Examples include 2,2′-bis (4- (methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.

  The aforementioned monofunctional polymerizable monomers are used alone or in combination of two or more thereof, or the aforementioned monofunctional polymerizable monomers and polyfunctional polymerizable monomers are used in combination. The polyfunctional polymerizable monomer can also be used as a crosslinking agent.

  A cross-linking agent may be used for the purpose of increasing the mechanical strength of the toner. As the crosslinking agent, the above-mentioned divinylbenzene is preferable, but the following crosslinking agents can also be used.

  Examples of the bifunctional crosslinking agent include the following. Bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol Diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate , Polyester type diacrylate (MANDA Nippon Kayaku), and dimethacrylate replaced with dimethacrylate.

  The following are mentioned as a polyfunctional crosslinking agent. Pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, diallyl phthalate, tri Allyl cyanurate, triallyl isocyanurate and triallyl trimellitate.

  The addition amount of these crosslinking agents is preferably 0.001 to 1.0 part by mass with respect to 100 parts by mass of the polymerizable monomer.

  The following are mentioned as a polymerization initiator used for this invention. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis Azo or diazo polymerization initiators such as -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl Peroxide-based polymerization initiators such as peroxide, lauroyl peroxide, tert-butyl-peroxypivalate.

  Although the usage-amount of these polymerization initiators changes with the target degree of polymerization, generally it is 3-20 mass parts with respect to 100 mass parts of polymerizable monomers. The kind of the polymerization initiator is slightly different depending on the polymerization method, but is selected with reference to the 10-hour half-life temperature and used alone or in combination.

  In the present invention, in order to control the degree of polymerization of the polymerizable monomer, a known chain transfer agent, polymerization inhibitor or the like can be further added and used.

  The toner of the present invention is a polar resin for easily achieving a core / shell structure, which is a preferred toner form, in order to obtain a stably charged toner or to achieve both low-temperature fixability and storage stability. Is preferably used.

  Polar resins include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, or copolymers of nitrogen-containing monomers and styrene-unsaturated carboxylic acid esters; nitriles such as acrylonitrile Monomer; Halogen-containing monomer such as vinyl chloride; Unsaturated carboxylic acid such as acrylic acid and methacrylic acid; Unsaturated dibasic acid; Unsaturated dibasic acid anhydride; Polymer of nitro monomer or Examples thereof include copolymers of styrene monomers and polyesters; epoxy resins. More preferred are styrene copolymers, maleic acid copolymers, saturated polyester resins, and epoxy resins.

  It is preferable that content of the said polar resin is 0.1-40 mass parts with respect to 100 mass parts of a polymerizable monomer or binder resin. The polar resin preferably has a peak molecular weight Mp measured by GPC of 5,000 to 250,000 and a weight average molecular weight Mw of 5,000 to 260,000. Furthermore, the polar resin preferably has a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 60 to 100 ° C., an acid value of 5 to 40, and Mw / Mn of 1.05 to 5.00.

  The toner used in the present invention preferably contains 0.5 to 50 parts by mass, preferably 3 to 30 parts by mass of a release agent (wax) with respect to 100 parts by mass of the binder resin. More preferably, it is 5 mass parts-20 mass parts. If content of a mold release agent is in said range, low temperature offset can be suppressed favorably, maintaining a long-term preservability. Also, good fluidity and image characteristics can be maintained without disturbing the dispersion of other toner materials.

  Examples of the wax include the following. Petroleum wax such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon wax and derivatives thereof according to the Fischer-Tropsch method; polyolefin wax such as polyethylene wax and polypropylene wax and derivatives thereof; carnauba wax Natural waxes such as candelilla wax and derivatives thereof. These derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, and animal waxes. Among these, ester wax and hydrocarbon wax are preferable from the viewpoint of excellent releasability.

  The wax used in the present invention has an endothermic peak derived from wax at a temperature of 60 ° C. or more and 100 ° C. or less in a DSC curve measured by a differential scanning calorimeter (DSC). From the viewpoint of

  Examples of the colorant preferably used in the present invention include the following organic pigments or dyes and inorganic pigments.

  As the organic pigment or organic dye as the cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, or a basic dye lake compound can be used.

  Specific examples include the following. C. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66.

  Examples of the organic pigment or organic dye as the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds.

  Specific examples include the following. C. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254, C.I. I. Pigment violet 19.

  As the organic pigment or organic dye as the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used.

  Specific examples include the following. C. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 191, 194.

  As the black colorant, carbon black and carbon black that is toned in black using the yellow / magenta / cyan colorant are used.

  These colorants can be used alone or in combination and further in the form of a solid solution. The colorant used in the toner of the present invention is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

  The colorant is preferably used by adding 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  In the present invention, when a toner is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase transfer property of the colorant. Therefore, it is preferable that the colorant be subjected to surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization. In particular, dyes and carbon blacks have many polymerization inhibiting properties, so care must be taken when using them.

  Examples of a method for suppressing the polymerization inhibitory property of the dye-based colorant include a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is used as a polymerizable monomer composition. Added.

  Carbon black may be treated with a material that reacts with the surface functional group of carbon black, for example, polyorganosiloxane, in addition to the same treatment as the above dye.

  In the toner of the present invention, a charge control agent can be mixed with toner particles as necessary. By blending the charge control agent, the charge characteristics are stabilized and the optimum triboelectric charge amount can be controlled.

  As the charge control agent, known ones can be used, and in particular, a charge control agent that has a high frictional charging speed and can stably maintain a constant triboelectric charge amount is preferable. Further, when the toner is produced by a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable.

  Examples of the charge control agent that control the toner to be negatively charged include organometallic compounds and chelate compounds. Examples thereof include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Others include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic anhydrides, esters, and phenol derivatives such as bisphenol. Furthermore, urea derivatives, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin charge control agents can be mentioned.

  On the other hand, examples of the charge control agent that control the toner to be positively charged include the following. Nigrosine modified products with nigrosine and fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like Onium salts such as certain phosphonium salts and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid , Ferricyanides, ferrocyanides); metal salts of higher fatty acids; resin-based charge control agents.

  The toner of the present invention can contain these charge control agents alone or in combination of two or more. Among these charge control agents, a salicylic acid-based compound containing a metal is preferable, and the metal is particularly preferably aluminum or zirconium. The most preferred charge control agent is an aluminum 3,5-di-tert-butylsalicylate compound. A preferable blending amount of the charge control agent is 0.01 to 20.0 parts by mass with respect to 100 parts by mass of the binder resin.

In the toner of the present invention, an external additive may be added to the toner particles for the purpose of improving the fluidity of the toner particles. External additives include the following fluororesin powders such as fine vinylidene fluoride powder and polytetrafluoroethylene fine powder; fatty acid metal salts such as zinc stearate, calcium stearate and lead stearate; titanium oxide powder, aluminum oxide Powder, metal oxide such as zinc oxide powder, or powder obtained by hydrophobizing the above metal oxide; and silica fine powder such as wet process silica and dry process silica, or silane coupling agent and titanium coupling agent on silica Examples thereof include surface-treated silica fine powder that has been surface-treated with a treating agent such as silicone oil. These treatment agents may be used alone or in combination.
The external additive may have the purpose of being added for uniform triboelectric charging of toner particles.

  The external additive is preferably used in an amount of 0.01 to 5 parts by mass with respect to 100 parts by mass of the toner particles.

  Hereinafter, a method for producing the toner particles will be described by exemplifying a suspension polymerization method suitable for obtaining the toner particles used in the present invention.

  Toner particles are prepared by dispersing a polymerizable monomer, a colorant, a wax and other additives as required in the production of the binder resin into a disperser such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic disperser. Therefore, it is dissolved or dispersed uniformly. In particular, after passing through a dispersion step of obtaining a colorant-containing monomer by dispersing at least a colorant in a polymerizable monomer by a known dispersion method, the colorant-containing monomer and resin obtained in the dispersion step It is preferable to carry out an adjustment step of mixing. A polymerization initiator is dissolved in this, and a polymerizable monomer composition is prepared.

  Next, toner particles are manufactured by suspending the polymerizable monomer composition in an aqueous medium containing a dispersant and performing polymerization. The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  As the dispersant, known inorganic and organic dispersants can be used.

  Specifically, examples of the inorganic dispersant include the following. Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina .

  On the other hand, examples of the organic dispersant include the following. Polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, starch.

  Further, commercially available nonionic, anionic and cationic surfactants can be used as the dispersant. Examples of such surfactants include the following. Sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate.

  As the dispersant, an inorganic poorly water-soluble dispersant is preferable, and it is preferable to use a poorly water-soluble inorganic dispersant that is soluble in an acid.

  In the present invention, when preparing an aqueous dispersion medium using a hardly water-soluble inorganic dispersant, the amount of these dispersants used is 0.2 to 100 parts by mass with respect to 100 parts by mass of the polymerizable monomer. It is preferable that it is 2.0 mass parts. Moreover, in this invention, it is preferable to prepare an aqueous dispersion medium using 300-3,000 mass parts water with respect to 100 mass parts of polymerizable monomer compositions.

  In the present invention, when preparing an aqueous dispersion medium in which the poorly water-soluble inorganic dispersant as described above is dispersed, a commercially available dispersant may be used as it is. Further, in order to obtain dispersant particles having a fine uniform particle size, the above water-insoluble inorganic dispersant may be produced in a liquid medium such as water under high-speed stirring to prepare an aqueous dispersion medium. For example, when tricalcium phosphate is used as a dispersant, it is possible to form a tricalcium phosphate microparticle by mixing a sodium phosphate aqueous solution and a calcium chloride aqueous solution under high-speed stirring.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples. In addition, all "parts" described in the examples indicate parts by mass.

  First, toner production examples used in the examples of the present invention will be described.

  The toner used in the examples of the present invention used toner particles produced by a suspension polymerization method, but the toner particles in the present invention are not necessarily limited to this, and a pulverization method, an emulsion polymerization aggregation method, Toner particles obtained by a dissolution suspension method can also be used.

<Production Example of Toner 1>
Toner particles 1 were produced by the suspension polymerization method as follows.
(Adjustment process of aqueous dispersion medium)
To the granulation tank, 350.00 parts of ion-exchanged water, 15.00 parts of trisodium phosphate, 8.00 parts of 10% by mass hydrochloric acid were added to prepare an aqueous sodium phosphate solution, and the mixture was heated to 60 ° C. Next, 9.00 parts of calcium chloride is dissolved. K. An aqueous dispersion medium containing a fine hardly water-soluble stabilizer Ca ₃ (PO ₄ ) ₂ was prepared by stirring for 30 minutes at a peripheral speed of 25 m / s using a homomixer (manufactured by Special Machine Industries). Further, 2.50 parts of sodium chloride was dissolved to obtain an aqueous dispersion medium.
(Preparation of polymerizable monomer composition 1: dispersion step)
-Styrene ... 30.00 parts-C.I. I. Pigment Red 122 4.50 parts C.I. I. CI Pigment Red 150 3.50 parts, negative charge control agent 1.00 parts (aluminum compound of 3,5-di-tert-butylsalicylic acid)
The above mixture was introduced into an attritor (manufactured by Nippon Coke), and stirred at 200 rpm for 180 minutes at 25 ° C. using zirconia beads having a radius of 1.25 mm to obtain a polymerizable monomer composition 1.
(Preparation of polymerizable monomer composition 2: dissolution step)
· Styrene ··· 44.00 parts · n-butyl acrylate ··· 26.00 parts · Polar resin A ··· 10.00 parts (styrene-methacrylic acid-methyl methacrylate-2- Hydroxyethyl methacrylate copolymer, Mw = 15200, Tg = 90 ° C., acid value Av = 25 mgKOH / g, hydroxyl value OHv = 8 mgKOH / g)
Polar resin B: 5.00 parts (polyester resin which is a polycondensate of propylene oxide-modified bisphenol A and terephthalic acid, Mw = 9500, Tg = 74 ° C., acid value Av = 9 mgKOH / g, hydroxyl group Value OHv = 25 mg KOH / g)
-Polar resin C: 1.50 parts (styrene-2-ethylhexyl acrylate copolymer containing 10% 2-acrylamido-2-methylpropanesulfonic acid, Mp = 18000)
The above mixture is put into a stirring tank capable of adjusting the temperature. K. Using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the mixture was dispersed and dispersed at a peripheral speed of 20 m / s for 180 minutes to obtain a polymerizable monomer composition 2.

(Adjustment process)
The polymerizable monomer composition 1 is added to the polymerizable monomer composition 2 and further mixed and dispersed at a peripheral speed of 20 m / s for 120 minutes. A mixture of was obtained. Subsequently, the temperature of the mixture was raised to 60 ° C. Next, the following materials were added, and stirring was further continued for 60 minutes at a peripheral speed of 20 m / s.
Wax 1 (behenyl behenate melting point 72 ° C.) 15.00 parts Divinylbenzene 0.20 parts Polymerization initiator (2,2′-azobis-isobutyrovaleronitrile ) 9.00 parts was added, and stirring was further continued for 5 minutes at a peripheral speed of 20 m / s.

(Granulation process)
The polymerizable monomer composition 3 was put into an aqueous dispersion medium, and the T.C. K. The mixture was stirred with a homomixer at a peripheral speed of 20 m / s. Subsequently, the liquid mixture in the granulation tank was continuously extracted from the lower part of the granulation tank, and the liquid mixture was returned and circulated to the upper part of the tank. The polymerizable monomer composition 3 was dispersed in an aqueous dispersion medium at a rotor peripheral speed of 40 m / s using a Cavitron (manufactured by Taiheiyo Kiko Co., Ltd.) provided in the circulation line. Circulation was repeated until the integrated flow rate that passed through the cavity was 5 times the amount of liquid charged in the granulation tank, to obtain a dispersion of the polymerizable monomer composition.

(Polymerization process)
In a reaction tank equipped with a paddle stirring blade, 46.70 parts of ion exchange water, 2.00 parts of trisodium phosphate, and 1.00 part of 10% by mass hydrochloric acid were added to prepare an aqueous sodium phosphate solution at 60 ° C. Warmed up. Next, 1.20 parts of calcium chloride is dissolved and stirred with a paddle stirring blade at a peripheral speed of 1.0 m / s for 30 minutes, so that the fine water-insoluble stabilizer Ca ₃ (PO ₄ ). _An aqueous dispersion medium containing ₂ was prepared. The dispersion of the polymerizable monomer composition was transferred to the reaction tank, and the temperature was raised to 70 ° C. while stirring with a paddle stirring blade at a peripheral speed of 1.5 m / s. After reacting for 5 hours, the temperature was further raised to 85 ° C. and reacted for 2 hours.

(Washing / filtration / drying / external addition process)
After cooling to 30 ° C., hydrochloric acid was added to adjust the pH to 1.4, and Ca ₃ (PO ₄ ) ₂ was dissolved. Further, after filtration and washing, the powder was dried at a temperature of 40 ° C. for 48 hours, coarse powder was removed using a sieve having an opening of 150 μm, and the particle diameter was adjusted to obtain magenta toner particles 1.

For 100.00 parts of the magenta toner particles obtained,
1.0 part of hydrophobic silica fine powder surface-treated with dimethyl silicone oil and hexamethyldisilazane (number average particle diameter of primary particles: 7 nm);
Add 1.0 part of hydrophobic titanium oxide fine particles (number average particle size of primary particles 15 nm) surface-treated with isobutytrimethoxysilane and dimethyl silicone oil,
Using a Henschel mixer (Mitsui Mining Co., Ltd.), mixing at 4000 rpm for 10 minutes gave Magenta Toner 1. Table 1 shows the physical properties of the obtained magenta toner.

<Production Example of Toner 2>
In the toner 1 production example, the amount of trisodium phosphate added in the aqueous dispersion medium adjustment step was changed to 10.00 parts, and the amount of 10 mass% hydrochloric acid added was changed to 5.30 parts. Further, the amount of calcium chloride added after heating to 60 ° C. was changed to 6.00 parts to prepare an aqueous dispersion medium containing a fine hardly water-soluble stabilizer Ca ₃ (PO ₄ ) ₂ . In addition, no sodium chloride was added. In the polymerization step, an aqueous dispersion medium containing a fine water-insoluble stabilizer Ca ₃ (PO ₄ ) ₂ was not prepared in advance in the reaction tank. Except for these, the magenta toner 2 was obtained in the same manner as in the toner 1 production example. Table 1 shows the physical properties of the obtained magenta toner.

<Production Example of Toner 3>
In the toner 1 production example, the amount of trisodium phosphate added in the aqueous dispersion medium adjustment step was changed to 10.00 parts, and the amount of 10 mass% hydrochloric acid added was changed to 5.30 parts. Further, the amount of calcium chloride added after heating to 60 ° C. was changed to 6.00 parts to prepare an aqueous dispersion medium containing a fine hardly water-soluble stabilizer Ca ₃ (PO ₄ ) ₂ . In addition, no sodium chloride was added. Except for these, the magenta toner 3 was obtained in the same manner as in the toner 1 production example. Table 1 shows the physical properties of the obtained magenta toner.

<Production Example of Toner 4>
In the toner 1 production example, the amount of trisodium phosphate added in the aqueous dispersion medium adjustment step was changed to 22.50 parts, and the amount of 10 mass% hydrochloric acid added was changed to 12.00 parts. Further, the amount of calcium chloride added after heating to 60 ° C. was changed to 13.50 parts, and an aqueous dispersion medium containing a fine hardly water-soluble stabilizer Ca ₃ (PO ₄ ) ₂ was prepared. Further, 3.75 parts of sodium chloride was added. In the dissolution step, the styrene addition amount was changed to 42.00 parts and the n-butyl acrylate addition amount was changed to 28.00 parts. Except for these, the magenta toner 4 was obtained in the same manner as in the toner 1 production example. Table 1 shows the physical properties of the obtained magenta toner.

<Production Example of Toner 5>
In the toner 1 production example, the amount of styrene added in the dissolving step was changed to 53.00 parts, and the amount of n-butyl acrylate added was changed to 17.00 parts. Otherwise, in the same manner as in the toner 1 production example, a magenta toner 5 was obtained. Table 1 shows the physical properties of the obtained magenta toner.

Example 1
In Example 1, the intermediate transfer belt 13 composed of two layers of the base layer 101 and the surface layer 102 was used. A method for manufacturing the intermediate transfer belt 13 will be described below.

<Preparation of base layer>
First, a method for manufacturing the base layer will be described. A bottle-shaped molded body was obtained by blow-molding a polyethylene naphthalate resin, and an endless belt body was obtained by cutting this with an ultrasonic cutter. In the polyethylene naphthalate resin, carbon black is dispersed as a resistance adjusting agent. The polyethylene naphthalate resin belt having a thickness of 70 μm thus obtained was used as the base layer 101 of the intermediate transfer belt 13.

<Preparation of surface layer forming coating solution>
Next, a method for producing a coating solution for forming the surface layer will be described. In a container shielded from ultraviolet rays,
Solid lubricant (PTFE particles having a particle size of 200 nm, Lubron: manufactured by Daikin Industries),
Lucifal (trade name, manufactured by Nippon Paint Co., Ltd.), which is an acrylic ultraviolet curable hard coat material containing pentaerythritol triacrylate and pentaerythritol tetraacrylate, was mixed. By adding a high molecular weight fluorine-based graft polymer GF400 (trade name, manufactured by Toagosei Co., Ltd.) and methyl isobutyl ketone as a dispersing agent for PTFE particles, and processing with a high-speed shearing disperser (homogenizer), coarse dispersion Went.

  Thereafter, the liquid subjected to the rough dispersion treatment was subjected to the main dispersion treatment using a high-pressure emulsification disperser (Nanobeta: manufactured by Yoshida Kikai Kogyo Co., Ltd.). Furthermore, the liquid after the final dispersion treatment of PTFE particles was completed while stirring a liquid obtained by adding an amine having a low molecular weight as a dispersing agent to Cellax (trade name, 210IP: manufactured by Nissan Chemical Industries, Ltd.) as conductive particles. The solution was dropped to obtain a coating solution for forming the surface layer.

<Preparation of intermediate transfer belt with surface layer>
Next, a method for forming the surface layer will be described. On the base layer of the intermediate transfer belt, the surface layer forming coating solution was dip-coated in a coating environment of 25 ° C. and a relative humidity of 60%. Then, 10 seconds after the coating is completed, ultraviolet rays are irradiated using an ultraviolet irradiation device (product name: UE06 / 81-3, manufactured by Eyegraphic Co., Ltd., integrated light quantity: 1000 mJ / cm2) in the same place as the coating environment. Then, the surface layer 102 was cured. As a result, a cured resin film having a thickness of 3 μm was formed, and this cured resin film was used as the intermediate transfer belt surface layer 102. Thus, the intermediate transfer belt 13 having the surface layer 102 was produced.

<Formation of grooves on the surface of the intermediate transfer belt>
Next, a groove shape 110 was formed on the surface layer 102 of the intermediate transfer belt obtained by the above method. The intermediate transfer belt 13 is elastically deformed and attached to a cylinder having an outer diameter slightly larger than the inner diameter of the intermediate transfer belt 13. A wrapping film (Lapika # 2000 (trade name), manufactured by KOVAX) using aluminum oxide with a grain size of 9 μm as abrasive grains is applied to the surface of the intermediate transfer belt mounted on the cylinder at a surface pressure of 1.96 N / mm ² . Make contact. Then, the above-described cylinder was rotated for 40 seconds to obtain an intermediate transfer belt 8 in which a groove shape 110 having a width 111 of 2 μm and a groove depth 112 of 1 μm was formed on the surface layer 102.

<Surface observation evaluation 1>
In-plane average roughness of the surface layer 102 in the observation field (toner weight average particle diameter of four sides) of the surface layer 102 of the produced intermediate transfer belt 13 was measured. A scanning probe microscope (SPI3800: manufactured by SII Nanotechnology Inc.) was used for the measurement. The cantilever was made of silicone and had a tip radius of 15 nm or less, a spring constant of 15 N / m, and a resonance frequency of 136 KHz. As the measurement mode, a dynamic force mode capable of obtaining a highly accurate image in nano order without destroying the sample was used. The measurement frequency was 0.3 to 1.0 Hz. The observation visual field was determined from the weight average particle diameter of the toner obtained from the measurement of the weight average particle diameter of the toner, and the in-plane average roughness (Ra) of the surface layer 102 in 6 μm square was measured. The in-plane average roughness of the surface layer 102 was measured as an average value at 10 arbitrary positions that do not overlap.

<Surface observation evaluation 2>
Ten-point average roughness Rzjis on the surface layer 102 of the produced intermediate transfer belt 13 was measured. For the measurement, a surface roughness / contour shape measuring instrument Surfcom 1500SD (manufactured by Tokyo Seimitsu) is used, in accordance with the standard JIS B0601: 2001, with a cutoff wavelength of 0.25 mm, a measurement reference length of 0.25 mm, and a measurement length of 1. It measured on 25 mm conditions. The ten-point average roughness Rzjis of the surface layer 102 is measured by scanning the stylus of the measuring device in a direction orthogonal to the moving direction of the surface of the intermediate transfer belt 13, and an average value of at least five arbitrary points is obtained as a measurement result. did.

<Surface observation evaluation 3>
The contact area ratio in the surface layer 102 of the produced intermediate transfer belt 13 was measured. For the measurement, a confocal microscope (OPTELICS, manufactured by Lasertec Corporation) was used. The observation area was 100 μm square, the measurement wavelength was 546 nm, the scan frequency in the thickness direction of the intermediate transfer belt was 0.2 μm, and the surface layer was scanned with a thickness of 3 μm. The contact area ratio was calculated with respect to the obtained surface shape by the following method.

A threshold is provided on the base layer side by 0.3 μm from the outermost surface portion of the measurement region, a region less than 0.3 μm from the outermost surface is defined as a contact region, and a region greater than 0.3 μm from the outermost surface is defined as a non-contact region formula,
Contact area ratio% = (area of contact area / area of observation area) × 100
Calculated by And the average value of arbitrary at least 5 places was made into the measurement result by the above-mentioned method. This value can represent the ratio of the contact area of the cleaning blade to the total area of the intermediate transfer belt within the range of the cleaning blade in a direction substantially perpendicular to the moving direction of the surface of the intermediate transfer belt.

<Evaluation of transfer efficiency>
The produced intermediate transfer belt 13 was attached to the image forming apparatus 100 of this embodiment shown in FIG. 1, and the transfer efficiency was evaluated. The toner was evaluated by filling all the toner containers 5 indicated by YMCK shown in FIG. The image pattern was a solid image developed from each station of YMC, and the amount of toner per unit area on the intermediate transfer belt was 1.3 mg / cm ² . The toner image having this image pattern was secondarily transferred by a secondary transfer bias optimum for the transfer material S. From the amount of toner before and after the secondary transfer, the transfer efficiency can be expressed as
Transfer efficiency% = (amount of transferred toner / amount of toner before transfer) × 100
Calculated by The transfer efficiency was evaluated at a basis weight of 75 under an environment of 25 ° C. and a relative humidity of 50%.
G / m ² of Xx4200 (trade name) was used as a transfer material. At this time, when the transfer efficiency was less than 94%, an image defect (toner granularity, white spots) at a level that could be visually confirmed occurred.

<Durability evaluation of cleaning performance>
In order to investigate the durability of the cleaning performance, using the image forming apparatus shown in FIG. 1, the prepared intermediate transfer belt 13 was attached, and the paper passing durability evaluation was performed. Specifically, in an environment of a temperature of 25 ° C. and a relative humidity of 50%, an extra basis weight of 80 g / m ² manufactured by OCE, using A4 paper, four sheets are intermittently printed up to 120,000 sheets for cleaning. The occurrence of defects was confirmed. At that time, the toner was evaluated by filling the toner 1 in all the cartridges of YMCK.

  The evaluation method for the cleaning performance is as follows. After printing the secondary color image (Y, M station toner) on the entire A4 size with the secondary transfer voltage turned off (0V), set the secondary transfer voltage to an appropriate value, Continue to pass the paper. By doing so, the toner of the Y and M stations that is hardly transferred to the transfer material S at the secondary transfer portion enters the cleaning blade. If they can be cleaned, the three sheets to be passed after that are output in a completely blank state, but if they cannot be cleaned, the toner that has passed through the cleaning blade is transferred onto the white paper and output as a poorly cleaned image. . The evaluation as described above was performed for every 10,000 sheets passed, and “A” was indicated if cleaning was possible after 120,000 sheets were passed, and “B” was indicated otherwise. The toner was replenished by replacing the process cartridge every time the printing became thinner.

  Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Examples 2 to 5)
In Examples 2 to 5, evaluation was performed in the same manner as in Example 1 except that the toner used in Example 1 was changed to toners 2 to 5. Table 1 shows the toner used in each example, the transfer efficiency evaluation, and the cleaning durability evaluation results.

(Example 6)
In the sixth embodiment, the transfer efficiency and cleaning in the intermediate transfer belt 13 in which the groove depth 112 is larger than that in the first embodiment, the groove width 111 is 2 μm, and the groove shape 110 having the groove depth 112 of 1.5 μm is formed. The performance was confirmed. The intermediate transfer belt 13 having the surface layer 102 was obtained in the same manner as in Example 1 except that the contact time of the wrapping film when forming the groove shape 110 on the surface layer 102 was 80 sec. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Example 7)
In Example 7, the transfer efficiency and cleaning performance were confirmed in the intermediate transfer belt 13 in which the groove width 111 was made smaller than that in Example 1, and the groove shape 110 having the groove width 111 of 1 μm and the groove depth 112 of 1 μm was formed. did. An intermediate transfer belt 13 having the surface layer 102 was obtained in the same manner as in Example 1 except that the pressing force of the wrapping film when forming the groove shape 110 on the surface layer 102 was changed to a surface pressure of 0.98 N / mm ² . Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Example 8)
In the eighth embodiment, transfer efficiency and cleaning performance in the intermediate transfer belt 13 in which the groove width 111 is larger than that in the first embodiment, and the groove shape 110 having the groove width 111 of 2.5 μm and the groove depth 112 of 1 μm is formed. It was confirmed. An intermediate transfer belt 13 having the surface layer 102 was obtained in the same manner as in Example 1 except that the pressing force of the wrapping film when forming the groove shape 110 on the surface layer 102 was changed to a surface pressure of 3.92 N / mm ² . Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

Example 9
In the ninth embodiment, the groove width 111 and the groove depth 112 are made larger than those in the first embodiment, and the intermediate transfer belt 13 in which the groove shape 110 having the groove width 111 of 2.5 μm and the groove depth 112 of 2 μm is formed. The transfer efficiency and cleaning performance were confirmed. An intermediate transfer belt 13 having the surface layer 102 was obtained in the same manner as in Example 1 except that the abrasive grain size of the wrapping film when forming the groove shape 110 on the surface layer 102 was 12 μm. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Comparative Example 1)
In Comparative Example 1, the transfer efficiency and cleaning performance of the intermediate transfer belt 13 in which the groove shape 110 was not formed on the surface layer 102 of the intermediate transfer belt were confirmed. An intermediate transfer belt 13 having a surface layer 102 was obtained in the same manner as in Example 1 except that the groove shape 110 by lapping was not formed after the surface layer 102 was formed. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Comparative Example 2)
In this comparative example, the transfer efficiency in the intermediate transfer belt 13 in which the groove shape 110 is made smaller than that in Example 7, and the groove shape 110 having a groove width 111 of 0.5 μm and a groove depth 112 of 0.3 μm is formed. And the cleaning performance was confirmed. An intermediate transfer belt 13 having the surface layer 102 was obtained in the same manner as in Example 1 except that the abrasive grain size of the wrapping film when forming the groove shape 110 on the surface layer 102 was 5 μm. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Comparative Example 3)
In Comparative Example 3, the transfer efficiency and cleaning of the intermediate transfer belt 13 in which the groove shape 110 is made larger than that in Example 9, and the groove shape 110 having a groove width 111 of 4 μm and a groove depth 112 of 2.5 μm is formed. The performance was confirmed. The surface layer 102 is provided in the same manner as in Example 1 except that the abrasive grain size of the wrapping film when forming the groove shape 110 on the surface layer 102 is 12 μm and the contact time of the wrapping film with the intermediate transfer belt 13 is 80 sec. An intermediate transfer belt 13 was obtained. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance.

(Comparative Example 4)
In Comparative Example 4, the transfer efficiency and the cleaning performance were confirmed using the intermediate transfer belt 13 in which a filler was added to the intermediate transfer belt surface layer 102 to give a random uneven shape. At the time of preparing the surface layer forming coating solution, 50 parts by weight of styrene / acryl resin fine particles having a particle diameter of 1 μm (Fineware: manufactured by Nippon Paint Co., Ltd.) were added for the purpose of imparting a shape to the surface layer 102. Otherwise, an intermediate transfer belt 13 having a surface layer 102 was obtained in the same manner as in Comparative Example 1. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance. On the surface of the intermediate transfer belt of Comparative Example 4, no groove shape was observed in the direction crossing the cleaning blade.

(Comparative Example 5)
In the comparative example, the transfer efficiency and the cleaning performance were confirmed using the intermediate transfer belt 13 to which a filler having a larger particle diameter than that of Comparative Example 4 was added to give a random uneven shape. At the time of preparing the surface layer forming coating solution, 50 parts by weight of melamine silica resin particles having a particle size of 2 μm (Opto Beads: manufactured by Nissan Chemical Industries, Ltd.) were added for the purpose of imparting a shape to the surface layer 102. Otherwise, an intermediate transfer belt 13 having a surface layer 102 was obtained in the same manner as in Comparative Example 1. Table 1 shows the evaluation results of durability of transfer efficiency and cleaning performance. On the surface of the intermediate transfer belt of Comparative Example 5, no groove shape was observed in the direction crossing the cleaning blade.

In order to obtain a transfer efficiency of 94% or more, it is necessary from the results of Example 9, Comparative Example 3 and Comparative Example 5 that the in-plane average roughness in the average particle diameter of the toner is 30 nm or less. I understand. Further, in order to satisfy the durability of the cleaning performance, it is necessary from the results of Example 5 and Comparative Example 4 that the surface layer 102 should have a groove shape that intersects the cleaning blade. Recognize. Further, from the results of Example 9, Comparative Example 1 and Comparative Example 2, it can be seen that the in-plane average roughness on the four sides of the weight average particle diameter of the toner needs to be 10 nm or more.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 5 Primary transfer roller 8 Intermediate transfer belt 12 Belt cleaning apparatus 15 Secondary transfer roller 21 Cleaning blade 22 Support member 81 Base layer of intermediate transfer belt 82 Surface layer of intermediate transfer belt 84 Groove 100 Image forming apparatus

Claims (10)

A charging step of charging the image bearing member with a charging means;
An exposure step of exposing the charged image carrier to form an electrostatic latent image;
A developing step of developing the electrostatic latent image with toner to form a toner image on the image carrier;
A transfer step of transferring the toner image to a transfer material via an intermediate transfer belt;
A fixing step of fixing the toner image on the transfer material, and a cleaning step of removing residual transfer toner remaining on the intermediate transfer belt with a cleaning blade;
An image forming method comprising:
The surface of the intermediate transfer belt has a groove shape in a direction crossing the cleaning blade,
The in-plane average roughness of the surface of the intermediate transfer belt in the toner weight average particle size square (D4 μm × D4 μm) is 10 nm or more and 30 nm or less,
The ten-point average roughness Rzjis of the surface of the intermediate transfer belt in the direction perpendicular to the rotation direction of the intermediate transfer belt is 0.26 μm or more and 0.67 μm or less,
The toner has toner particles containing a binder resin, a colorant and a release agent;
The toner particles are toner particles produced by a suspension polymerization method;
The aspect ratio of the toner measured by a flow type particle image measuring device having an image processing resolution of 512 × 512 pixels (0.19 μm × 0.19 μm per pixel) is 0.850 or more,
The glass transition point Tg (T) of the toner is 50.0 ° C. or higher and 70.0 ° C. or lower,
The ratio of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm to toner particles having an equivalent circle diameter of 0.25 μm or more and less than 39.5 μm of the toner is 1.0 number% or more and 15.0 numbers % Or less,
An image forming method, wherein the toner satisfies the relationship of the following formula (1).
Tg (N) −Tg (T) ≧ 1.5 Formula (1)
(In formula (1), Tg (N) represents the glass transition point of toner particles having an equivalent circle diameter of 0.25 μm or more and less than 1.98 μm of the toner.) The image forming method according to claim 1, wherein a contact area ratio of the cleaning blade is 80% or more and 97% or less with respect to a total area of the surface of the intermediate transfer belt.   The image forming method according to claim 1, wherein a width of the groove shape is less than half of a weight average particle diameter of the toner. The intermediate transfer belt is composed of two or more layers,
The image forming method according to claim 1, wherein a surface layer of the intermediate transfer belt contains a curable resin.   The image forming method according to claim 4, wherein the curable resin is an acrylic copolymer.   The image forming method according to claim 4, wherein the surface layer of the intermediate transfer belt further contains fluorine-containing particles.   The image forming method according to claim 6, wherein the fluorine-containing particles are polytetrafluoroethylene (PTFE).   The image forming method according to claim 1, wherein the cleaning blade is a blade made of polyurethane rubber.   The image forming method according to claim 1, wherein the cleaning blade has a hardness of 70 degrees or more and 80 degrees or less according to JIS K6253 standard.   The image forming method according to claim 1, wherein the cleaning blade is in contact with the intermediate transfer belt in a counter direction.