JP5929335B2 - Non-magnetic one-component toner, toner cartridge, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a non-magnetic one-component toner, a toner cartridge, a process cartridge, and an image forming apparatus.

  A method for visualizing image information through an electrostatic latent image, such as electrophotography, is currently used in various fields. In electrophotography, an electrostatic latent image is formed on an electrophotographic photoreceptor (photoreceptor drum) by charging and exposure processes, the electrostatic latent image is developed with toner, and then visualized through transfer and fixing processes. Is done. As a developing process method for developing the electrostatic latent image with toner, a non-magnetic one-component developing method, a magnetic one-component developing method, a two-component developing method, and the like are known.

  In the non-magnetic one-component development method, for example, an external additive such as silica or titanium oxide is attached to the surface of a non-magnetic toner particle containing a colorant, a binder resin, etc. and not containing a magnetic substance such as magnetic powder. Nonmagnetic one-component toner is used. In the magnetic one-component development method, a magnetic one-component toner including magnetic toner particles containing magnetic powder is used. In the two-component development method, a two-component developer having the nonmagnetic toner particles to which an external additive is attached and a magnetic carrier is used.

  For example, toners described in Patent Documents 1 to 4 are known as non-magnetic one-component toners.

  Patent Document 1 includes toner particles containing a binder resin containing a crystalline polyester resin and an amorphous resin and a colorant, and inorganic fine particles attached to the surface of the toner particles. A non-magnetic one-component toner having a coverage of 130% to 300% is disclosed.

  Patent Document 2 includes toner particles containing at least a polyester resin, a colorant, and a release agent, and an external additive attached to the surface of the toner particles. The coverage of the external additive on the toner particles is 70% or more and 210. % Non-magnetic one-component toner is disclosed.

  Patent Document 3 discloses toner particles containing a colorant and a binder resin, an external additive containing silica having an average particle diameter of 20 nm to 80 nm and alumina having an average particle diameter of 50 nm to 300 nm attached to the toner particle surface; And a non-magnetic one-component toner in which the coverage of the external additive to the toner particles is 100% or more.

  Patent Document 4 includes toner particles including a colorant and a binder resin, and two types of external additives, and one type of external additive has a volume average particle diameter of 5 nm or more and less than 50 nm, A non-magnetic one-component toner is disclosed in which the volume average particle size of the seed is 50 nm or more and less than 300 nm, and the coverage of the external additive on the toner particles is 50% or more and 130% or less.

JP 2003-107781 A JP 2004-109200 A JP 2008-96539 A JP 2006-276060 A

  An object of the present invention is to provide a non-magnetic one-component toner, a toner cartridge, a process cartridge, and an image forming apparatus that suppress toner drop stains seen on an image.

The invention according to claim 1 includes toner particles including a colorant and a binder resin, and an external additive attached to the surface of the toner particles, wherein the external additive includes first particles and the first particles. Second particle having a number average particle diameter of 6 times or more of the number average particle diameter of the toner particles, and the coverage of the first particles with respect to the toner particles is 90% or more and 150% or less. coverage of 2 particles Ri der less than 50% 5%, the shape factor SF1 of the second particles are non-magnetic one-component toner is 135 to 140.

The invention according to claim 2, wherein the binder resin is a non-magnetic one-component toner of claim 1 Symbol placement is a polyester resin.

A third aspect of the present invention is a toner cartridge containing the non-magnetic one-component toner according to any one of the first to second aspects.

According to a fourth aspect of the present invention, a toner image is formed by developing the electrostatic latent image formed on the surface of the image carrier using the nonmagnetic one-component toner according to any one of the first or second aspect. A process cartridge having developing means.

According to a fifth aspect of the present invention, there is provided an image holding member, a charging unit that charges the surface of the image holding member, a latent image forming unit that forms an electrostatic latent image on the charged surface of the image holding member, transfer for transferring a developing means for forming a developed toner image using a non-magnetic one-component toner according to the electrostatic latent image to any one of claims 1-2, the developed toner image onto a recording medium And an image forming apparatus.

  According to the first aspect of the present invention, the toner drop and dirt are suppressed as compared with the case where the present configuration is not provided.

  According to the second aspect of the present invention, the toner drop and dirt are suppressed as compared with the case without this configuration.

  According to the third aspect of the present invention, the toner drop and dirt are suppressed as compared with the case without this configuration.

  According to the fourth aspect of the present invention, the toner drop and dirt are suppressed as compared with the case without this configuration.

  According to the fifth aspect of the present invention, the toner drop and dirt are suppressed as compared with the case without this configuration.

1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to an exemplary embodiment. 1 is a schematic configuration diagram illustrating an example of a configuration of a developing device used in an image forming apparatus according to an exemplary embodiment. FIG. 5 is a schematic diagram illustrating a contact state between a nonmagnetic one-component toner and a toner layer regulating member according to the exemplary embodiment. FIG. 4 is a schematic diagram illustrating a contact state between a nonmagnetic one-component toner using a first particle as an external additive and a toner layer regulating member. FIG. 6 is a schematic diagram illustrating a contact state between a nonmagnetic one-component toner and a toner layer regulating member when the coverage of first particles and second particles is different from the range of the present embodiment. FIG. 6 is a schematic diagram illustrating a contact state between a nonmagnetic one-component toner and a toner layer regulating member when the coverage of first particles and second particles is different from the range of the present embodiment. FIG. 6 is a schematic diagram illustrating a contact state between a nonmagnetic one-component toner and a toner layer regulating member when the volume average particle diameters of first particles and second particles are different from the range of the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

  FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to the present embodiment. In the image forming apparatus 200 shown in FIG. 1, four electrophotographic photosensitive members (image holding members) 401 a to 401 d are arranged along an intermediate transfer belt 409 in a housing 400. The electrophotographic photoreceptors 401a to 401d form, for example, an image in which the electrophotographic photoreceptor 401a is yellow, the electrophotographic photoreceptor 401b is magenta, the electrophotographic photoreceptor 401c is cyan, and the electrophotographic photoreceptor 401d is black.

  In the present embodiment, the electrophotographic photoreceptors 401a to 401d can be rotated in a predetermined direction, and charging rolls 402a to 402d for charging the electrophotographic photoreceptors 401a to 401d along the rotation direction, and exposure to be described later. Developing devices 404a to 404d for developing the electrostatic latent images written on the electrophotographic photoreceptors 401a to 401d by the device 403 with toner (the specific device configuration of the developing device will be described later with reference to FIG. 2), electronic Primary transfer rolls 410a to 410d for transferring toner images formed on the photoconductors 401a to 401d to the intermediate transfer belt 409, cleaning blades 415a to 415d for removing residual toner on the electrophotographic photoconductors 401a to 401d, and the like are arranged. Has been. In the housing 400, for example, toner cartridges 405a to 405d that contain toners of four colors, black, yellow, magenta, and cyan, are installed. Then, toners of four colors, black, yellow, magenta, and cyan, stored in the toner cartridges 405a to 405d are supplied from a supply pipe (not shown) to the developing devices 404a to 404d. For these four color toners, the non-magnetic one-component toner according to this embodiment is used. Hereinafter, the non-magnetic one-component toner may be simply referred to as toner.

  In addition, an exposure device 403 is installed in the housing 400 of the present embodiment, and a light beam emitted from the exposure device 403 is irradiated on the surfaces of the electrophotographic photosensitive members 401a to 401d after charging, thereby causing electrostatic latent images. An image is formed. As the exposure device 403, for example, an optical system device that exposes a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like on the surface of the electrophotographic photoreceptors 401a to 401d is used.

  The charging rolls 402a to 402d according to the present embodiment are in contact with the electrophotographic photosensitive members 401a to 401d to apply a voltage to the electrophotographic photosensitive members 401a to 401d, so that the electrophotographic photosensitive members 401a to 401d are set to a predetermined potential. It is to be charged. In addition to the charging roll shown in this embodiment, charging by a contact charging method or a non-contact charging method may be performed using a charging brush, a charging film, a charging tube, or the like. Moreover, you may charge by the non-contact system using a corotron or a scorotron.

  The intermediate transfer belt 409 of this embodiment is supported by a drive roll 406, a backup roll 408, and a tension roll 407, and rotates by the rotation of these rolls. The intermediate transfer belt 409 is constituted by a film-like belt in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide.

  The primary transfer rolls 410a to 410d of the present embodiment are disposed to face the electrophotographic photoreceptors 401a to 401d with the intermediate transfer belt 409 interposed therebetween. The primary transfer rolls 410a to 410d of the present embodiment include a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical bar made of a metal such as iron or SUS. The sponge layer is formed of a blended rubber of acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and ethylene-propylene-diene rubber (EPDM) blended with a conductive agent such as carbon black, for example. It is a roll. A voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer rolls 410a to 410d. As a result, the toner images of the respective electrophotographic photosensitive members 401 a to 401 d are sequentially electrostatically attracted to the intermediate transfer belt 409, and a superimposed toner image is formed on the intermediate transfer belt 409.

  The cleaning blades 415a to 415d are for removing residual toner adhering to the surfaces of the electrophotographic photosensitive members 401a to 401d. Examples of the material include urethane rubber, neoprene rubber, and silicone rubber.

  In this embodiment, the secondary transfer roll 413 is disposed so as to face the backup roll 408 with the intermediate transfer belt 409 interposed therebetween. The backup roll 408 includes, for example, an inner layer portion that includes EPDM rubber and a tubular surface layer that includes a blend rubber of EPDM and NBR in which carbon is dispersed. The backup roll 408 forms a counter electrode of the secondary transfer roll 413 and is applied with a secondary transfer bias.

  The secondary transfer roll 413 of the present embodiment includes a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical bar made of a metal such as iron or SUS. The sponge layer is, for example, a sponge-like cylindrical roll formed from a blend rubber of NBR, SBR, and EPDM blended with a conductive agent such as carbon black. The secondary transfer roll 413 is pressed against the backup roll 408 with the intermediate transfer belt 409 interposed therebetween, and the secondary transfer roll 413 is grounded to form a secondary transfer bias with the backup roll 408. The toner image is secondarily transferred onto the recording medium 500 conveyed to the next transfer roll 413.

  On the downstream side of the secondary transfer roll 413 of the intermediate transfer belt 409, a cleaning blade 416 for removing residual toner and the like on the intermediate transfer belt 409 after the secondary transfer and cleaning the surface of the intermediate transfer belt 409 is provided. Yes. Examples of the material include urethane rubber, neoprene rubber, and silicone rubber.

  Further, the image forming apparatus 200 of the present embodiment includes a paper tray 411 that accommodates the recording medium 500, a transfer roll 412 that transports the recording medium 500 in the paper tray 411, and two fixing rolls 414 that are opposed to each other. It is equipped with.

  The toner cartridges (405a to 405d) according to the present embodiment include a non-magnetic one-component toner for replenishment that is attached to and removed from the image forming apparatus and is supplied to at least a developing device provided in the image forming apparatus. It is. The process cartridge according to the present embodiment has a cartridge structure that is detachable from the image forming apparatus, and develops the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a non-magnetic one-component toner. And at least a developing device for forming a toner image. The developing devices 404a to 404d constituting the process cartridge will be described below.

  FIG. 2 is a schematic configuration diagram illustrating an example of a configuration of a developing device used in the image forming apparatus of the present embodiment. A developing device 404 (404a to 404d) shown in FIG. 2 is arranged in contact with an electrophotographic photosensitive member 401 (401a to 401d) that rotates in the direction of arrow A by a driving source (not shown), and rotates the electrophotographic photosensitive member 401. Accordingly, the developing roll 12 that rotates in the direction of arrow B, the bias power source 14 connected to the developing roll 12, and the position downstream of the contact portion between the developing roll 12 and the electrophotographic photosensitive member 401 in the rotating direction of the developing roll 12. In addition, a toner scraping member 16 that is disposed in contact with the developing roll 12 and rotates in the direction of arrow C so as to run against the rotation of the developing roll 12, and in the rotating direction of the developing roll 12, the developing roll 12 and the toner At a position downstream of the contact portion with the scraping member 16 and upstream of the contact portion between the developing roll 12 and the electrophotographic photosensitive member 401, the developing roller The toner layer regulating member 18 disposed so as to be in contact with the toner 12 and the side of the developing roll 12 opposite to the side on which the electrophotographic photosensitive member 401 is disposed, and the opening on the side on which the developing roll 12 is disposed. And a stirring member 20 disposed in the housing 22.

  One end of the toner layer regulating member 18 is fixed to the opening of the housing 22 so as to close the opening of the housing 22. The side of the opening of the housing 22 opposite to the side on which the toner layer regulating member 18 is attached (upper side of the opening) (lower side of the opening) covers the lower side of the developing roll 12 and the toner scraping member 16. It is configured. The nonmagnetic one-component toner 24 in the housing 22 is supplied from a toner cartridge (not shown). Then, it is desirable to fill the space between the developing roll 12 and the lower side of the opening of the housing 22 with the non-magnetic one-component toner 24 without gaps and to deposit the toner scraping member 16 in the housing 22. . Further, the nonmagnetic one-component toner 24 is supplied from the inside of the housing 22 to the opening side of the housing 22 where the developing roll 12 is disposed by the stirring member 20 provided in the housing 22. ing. In the case where the developing device 404 has an integrated cartridge that also has a toner cartridge function, a necessary amount of toner may be stored around the stirring member 20 in advance.

  As the developing roll 12, for example, a conductive roll composed of conductive urethane rubber or the like with a conductive agent such as carbon black added to the surface, a metal roll whose surface is grooved or sandblasted, and the surface is a resin A coated rubber roll, a metal roll whose surface is resin-coated, or the like is used.

  Examples of the toner layer regulating member 18 include a plate-like member made of metal, rubber, etc., a member obtained by plating the surface of the plate-like member, and a member coated with a resin on the surface of the plate-like member. Used.

  Next, a basic image forming process of the image forming apparatus 200 according to the present embodiment will be described.

  In an image forming apparatus 200 as shown in FIG. 1, image data output from an image reading apparatus (IIT) (not shown), a personal computer (PC) (not shown), or the like is received by an image processing apparatus (IPS) ( Image processing is performed by (not shown). The image data that has been subjected to image processing is converted into color material gradation data of four colors of yellow, magenta, cyan, and black, and is output to the exposure device 403.

  In the electrophotographic photoreceptors 401a to 401d, the surfaces are charged by the charging rolls 402a to 402d (charging process). Then, according to the input color material gradation data, the exposure device 403 scans and exposes the surface to form an electrostatic latent image (latent image forming step). The formed electrostatic latent images are developed as toner images of yellow, magenta, cyan, and black by developing devices 404a to 404d (developing step). This development step will be described in detail later. Next, the primary transfer rolls 410a to 410d apply a voltage (primary transfer bias) opposite to the toner charging polarity to the base material of the intermediate transfer belt 409, and sequentially transfer the toner images onto the surface of the intermediate transfer belt 409. Primary transfer is performed by superimposing (primary transfer process).

  The toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 409, and then the toner images are conveyed to the secondary transfer roll 413. When the toner image is conveyed to the secondary transfer roll 413, the transfer roll 412 rotates in accordance with the conveyance timing, and the recording medium 500 having a predetermined size is supplied from the paper tray 411. The recording medium 500 supplied by the transfer roll 412 is temporarily stopped before reaching the secondary transfer roll 413, and a registration roll (not shown) according to the movement timing of the intermediate transfer belt 409 on which the toner image is held. , The position of the recording medium 500 and the position of the toner image are aligned. Then, the secondary transfer roll 413 is pressed against the backup roll 408 via the intermediate transfer belt 409. At this time, the recording medium 500 conveyed at the same timing is sandwiched between the intermediate transfer belt 409 and the secondary transfer roll 413. At that time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity is applied to the secondary transfer roll 413, a transfer electric field is formed between the secondary transfer roll 413 and the backup roll 408. . The unfixed toner image held on the intermediate transfer belt 409 is pressed by the secondary transfer roll 413 and the backup roll 408 and electrostatically transferred onto the recording medium 500 (secondary transfer process). Thereafter, the recording medium 500 on which the toner image is electrostatically transferred is peeled off from the intermediate transfer belt 409 by the secondary transfer roll 413 and transferred to the fixing roll 414.

  The unfixed toner image on the recording medium 500 conveyed to the fixing roll 414 is subjected to fixing processing by, for example, heat and pressure by the fixing roll 414 and is fixed on the recording medium 500 (fixing step). Then, the recording medium on which the fixed image is formed is transferred to the outside of the housing 400 by the transfer roll 412. On the other hand, after the transfer to the recording medium 500 is completed, residual toner remaining on the intermediate transfer belt 409 is removed from the intermediate transfer belt 409 by the cleaning blade 416.

  Next, the operation of the developing device 404 (404a to 404d) used in the image forming apparatus 200 according to the present embodiment will be described.

  First, the toner cartridges 405a to 405d shown in FIG. 1 are rotationally driven by a driving device (not shown), and the nonmagnetic one-component toner 24 accommodated in the toner cartridges 405a to 405d is opened in the toner cartridges 405a to 405d. (Not shown) is supplied into the housing 22 of the developing device 404 shown in FIG. During development, the nonmagnetic one-component toner 24 in the housing 22 is supplied from the stirring member 20 to the surface of the developing roll 12 by the toner scraping member 16. Next, the non-magnetic one-component toner 24 attached to the surface of the developing roll 12 is attached by the toner layer regulating member 18 so as to form a toner layer having a predetermined thickness on the surface of the developing roll 12. Subsequently, it adheres to the surface of the developing roll 12 according to the potential difference between the surface of the electrophotographic photosensitive member 401 on which the electrostatic latent image is formed and the developing roll 12 to which the bias voltage is applied by the bias power source 14. The nonmagnetic one-component toner 24 moves to the electrophotographic photosensitive member 401 side, and the electrostatic latent image is developed. Then, after development, the nonmagnetic one-component toner 24 remaining on the surface of the developing roll 12 is scraped off by the toner scraping member 16.

  Next, the nonmagnetic one-component toner according to this embodiment will be described.

  The nonmagnetic one-component toner of this embodiment has toner particles containing a colorant and a binder resin, and an external additive attached to the toner particle surface, and does not use a magnetic material for the toner. The external additive of this embodiment contains 1st particle | grains and 2nd particle | grains which have a number average particle diameter 3 times or more of the number average particle diameter of 1st particle | grains. The external additive of the present embodiment has a number average particle diameter of more than 1 to less than 3 times the number average particle diameter of the first particles as long as at least the first particles and the second particles are included. Particles or the like may be included. Examples of the first particles and the second particles include inorganic particles such as silica particles, titania particles, alumina particles, and zinc oxide particles. The first particles and the second particles may be the same type of particles such as silica particles, or may be different types of particles such as silica particles and titania particles. In the non-magnetic one-component toner of this embodiment, the coverage of the first particles with respect to the toner particles is 90% or more and 150% or less, and the coverage of the second particles with respect to the toner particles is 5% or more and 50% or less. . The volume average particle diameter of the toner particles, the number average particle diameter of the external additive particles, the coverage, and the exposure ratio are obtained as follows.

<Volume average particle diameter of toner particles>
The volume average particle diameter is measured by measuring with an aperture diameter of 100 μm using a Coulter Multisizer II type (manufactured by Beckman-Coulter). As a measuring method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of the particles is measured. The number of particles to be measured is 50,000.

  The volume average particle size of the toner particles is determined from the smaller diameter side with respect to the particle size range (channel) divided based on the particle size distribution measured by the above-mentioned Coulter Multisizer II type (manufactured by Beckman-Coulter). The particle size is a cumulative distribution of 50%.

(Measurement method of coverage)
The coverage of the first particles or the second particles with respect to the toner particles is calculated as follows.

Dt: Toner particle size ρt: Toner specific gravity Da: External additive particle size ρa: External additive specific gravity

(Measurement method of exposure rate)
The toner particle exposure rate was determined by measuring the toner with an X-ray photoelectron spectrometer (JPS-9000MX) manufactured by JASCO Corporation under the conditions of an X-ray source MgKα and an output of 10 kV. It is calculated | required by calculating.

  Next, the contact state between the nonmagnetic one-component toner of this embodiment and the toner layer regulating member will be described. However, the contact state between the toner and the toner layer regulating member, which will be described below, can be considered as an estimation, and is not interpreted in a limited manner.

  FIG. 3 is a schematic view showing a contact state between the nonmagnetic one-component toner and the toner layer regulating member of the present embodiment. FIG. 4 is a schematic view showing a contact state between the nonmagnetic one-component toner using the first particles as an external additive and the toner layer regulating member. 5 and 6 are schematic views showing the contact state between the nonmagnetic one-component toner and the toner layer regulating member when the coverage of the first particles and the second particles is different from the range of the present embodiment. FIG. 7 is a schematic diagram showing a contact state between the nonmagnetic one-component toner and the toner layer regulating member when the volume average particle diameters of the first particles and the second particles are different from the range of the present embodiment.

  As described above, the volume average particle diameter of the second particles 26a is set to three times or more the volume average particle diameter of the first particles 28a, and the coverage of the first particles 28a with respect to the toner particles 30a is set to 90% or more and 150% or less. By setting the coverage of the second particles 26a with respect to the toner particles 30a to 5% or more and 50% or less, the surface of the toner particles 30a is mainly formed on the surface of the toner particles 30a as in the nonmagnetic one-component toner of this embodiment shown in FIG. One particle 28a adheres, and the second particle 26a adheres to the surface of the first particle 28a. Generally, the external additive attached to the toner particle surface is easily fixed in a state where a part of the external additive is buried in the toner particle, and thus the first particle is fixed on the toner particle surface. The toner particles are difficult to be fixed to each other, and the surface of the toner particles is hidden by the first particles, and the second particles are hardly contacted with the toner particles. Therefore, in the toner of the present embodiment, the adhesion force of the second particles 26a attached to the surface of the first particles 28a is weaker than the adhesion force of the first particles 28a attached to the surface of the toner particles 30a, and thus the surface of the first particles 28a. Is likely to move (for example, it moves in the direction of arrow A shown in FIG. 3).

  Here, when a toner layer having a predetermined thickness is formed on the surface of the developing roll 12 by the toner layer regulating member 18, as shown in FIG. 3, the particles that come into contact with the toner layer regulating member 18 become toner particles 30 a. There are more second particles 26a moving on the surface of the first particles 28a than the attached first particles 28a. Therefore, in the non-magnetic one-component toner of this embodiment, the contact area between the toner layer regulating member 18 and the particles is a non-magnetic one-component toner in which the first particles 28b are attached to the toner particles 30b as shown in FIG. The coverage of the first particles with respect to the toner particles is smaller than that in the present embodiment).

  Further, when the nonmagnetic one-component toner of the present embodiment shown in FIG. 3 comes into contact with the toner layer regulating member 18 and the surface of the toner layer regulating member 18 is rubbed by the toner, the second particles 26a are placed on the first particles 28a. Therefore, it is considered that the frictional force between the toner layer regulating member 18 and the toner is reduced as compared with the case of the nonmagnetic one-component toner of FIG. 4 in which the first particles 28b are attached to the toner particles 30b. .

  As described above, the nonmagnetic one-component toner of the present embodiment can suppress the contact area and the frictional force with the toner layer regulating member 18, so that even if the surface of the toner layer regulating member 18 is rubbed by the toner, the toner layer regulating member The surface of 18 is prevented from being damaged by the toner. When the toner layer regulating member 18 is scratched, the toner is easily fixed to the toner layer regulating member 18, and the contact state between the toner layer regulating unit and the developing roll is changed at a predetermined thickness in the portion where the toner is fixed. The toner layer on the developing roll becomes unstable, the toner charge is reduced, and the transport amount becomes excessive, so that the toner drops on the image on the recording medium. Dirt may occur. However, the non-magnetic one-component toner of the present embodiment hardly damages the surface of the toner layer regulating member 18 as described above even when the surface of the toner layer regulating member 18 is rubbed by the toner. Since the toner is prevented from sticking, it is considered that the occurrence of the toner drop stain on the image on the recording medium can be suppressed.

  5 and 6, the number average particle diameter of the second particles 26 b is set to be three times or more the number average particle diameter of the first particles 28 c as in the present embodiment. The coverage of the first particles 28c to 30c is less than 90%, and the coverage of the second particles 26b to the toner particles 30c is more than 5%. When the volume average particle diameter and the coverage of the first particles 28c and the second particles 26b are set in this way, the first particles 28c and the second particles 26b are fixed on the surface of the toner particles 30c as shown in FIG. . In addition, as shown in FIG. 6, there may be a structure in which the second particles adhere to the first particles, but the interval between the first particles 28 c is the same as that of the first particles 28 a of the present embodiment shown in FIG. 4. Since the width is larger than the interval, the second particle 26b is sandwiched between the first particles 28c having the wide interval like the non-magnetic one-component toner of FIG. Since the step formed by the particles becomes large, it is considered that the second particles 26b are difficult to move on the first particles 28c. 5 and 6, the toner particle exposure rate exceeds 30%. In the nonmagnetic one-component toner of FIG. 7, the coverage of the first particles 28d and the second particles 26c with respect to the toner particles 30d is the same as that of this embodiment, but the number average particle size of the second particles 26c is the first. More than 1 to less than 3 times the number average particle diameter of the particles 28d. When the number average particle diameter and the coverage of the first particles 28d and the second particles 26c are set in this way, the first particles 28d are fixed on the surface of the toner particles 30d as shown in FIG. Although the second particles 26c adhere to the surface, the step formed by the first particles with respect to the curvature of the second particles does not increase, so the second particles 26c are sandwiched between the first particles 28d, and the second particles It is considered that 26c is difficult to move on the first particle 28d.

  Any of the non-magnetic one-component toners shown in FIGS. 5 to 7 is mainly composed of the second particles (26b, 26c) when a toner layer having a predetermined thickness is formed on the surface of the developing roll 12 by the toner layer regulating member 18. Comes into contact with the surface of the toner layer regulating member 18. However, in the non-magnetic one-component toner of FIG. 5, the second particles 26 b that have adhered to the surface of the toner particles 30 c and have not moved easily come into contact with the surface of the toner layer regulating member 18. This frictional force is considered to increase as compared with the non-magnetic one-component toner of FIG. 6 and 7, the second particles (26b, 26c) attached to the first particle surfaces (28c, 28d) are in contact with the surface of the toner layer regulating member 18. However, the second particles (26b, 26c) are sandwiched between the first particles (28c, 28d) due to the relationship between the coverage rate and the volume average particle size, and the nonmagnetic one component of this embodiment shown in FIG. It is harder to move freely than the second toner particles 26a. Therefore, it is considered that the frictional force between the toner layer regulating member 18 and the nonmagnetic one-component toner shown in FIGS. 6 and 7 increases as compared with the nonmagnetic one-component toner shown in FIG. As a result, the nonmagnetic one-component toner of this embodiment shown in FIG. 3 is less likely to be scratched on the surface of the toner layer regulating member 18 than the nonmagnetic one-component toner shown in FIGS. Since the toner is prevented from sticking, it is considered that the occurrence of the toner drop stain on the image on the recording medium can be suppressed.

  Next, each member of the nonmagnetic one-component toner according to this embodiment will be described.

  The colorant constituting the toner particles may be a dye or a pigment, but is preferably a pigment from the viewpoint of light resistance and water resistance. Examples of colorants include carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose. Bengal, Quinacridone, Benzidine Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, 185, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. A known pigment such as CI Pigment Blue 15: 3 is used.

  The binder resin constituting the toner particles is not particularly limited, and a known resin is used. For example, it is preferable to include a polyester resin from the viewpoint of low-temperature fixability. Normally, when a polyester resin is used as the binder resin, the toner is easily fixed to the toner layer regulating member. However, in the non-magnetic one-component toner of the present embodiment, even if the polyester resin is used as the binder resin, the toner layer regulation Toner sticking to the member is suppressed.

  The resin other than the polyester resin is not particularly limited. Specifically, styrenes such as styrene, parachlorostyrene, and α-methylstyrene, methyl acrylate, ethyl acrylate, n-propyl acrylate, butyl acrylate, Acrylic monomers such as lauryl acrylate and 2-ethylhexyl acrylate, methacrylic monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, and acrylic Acid, methacrylic acid, ethylenically unsaturated acid monomers such as sodium styrenesulfonate, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl methyl ketone, vinyl Vinyl ketones such as ruethyl ketone and vinyl isopropenyl ketone, homopolymers of olefin monomers such as ethylene, propylene and butadiene, copolymers obtained by combining two or more of these monomers, or mixtures thereof; , Epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or a mixture of these with the vinyl resins, and by polymerizing vinyl monomers in the presence of these resins The obtained graft polymer etc. are mentioned. These resins may be used alone or in combination of two or more.

  The toner particles contain a colorant and a binder resin, but may contain other components such as a release agent in addition to these components. Examples of the release agent include paraffin waxes such as low molecular weight polypropylene and low molecular weight polyethylene, silicone resins, rosins, rice wax, carnauba wax and the like. The melting point of the release agent is preferably 50 ° C. or higher, and more preferably 60 ° C. or higher, from the viewpoint of storage stability. Further, from the viewpoint of offset resistance, the temperature is desirably 110 ° C. or less, and more desirably 100 ° C. or less. The content of the release agent in the toner particles is preferably from 0.5% by mass to 15% by mass, and more preferably from 1.0% by mass to 12% by mass. When the content of the release agent is 0.5% by mass or more, it is easy to prevent peeling failure particularly in the case of oilless fixing. When the content of the release agent is 15% by mass or less, deterioration of toner fluidity is suppressed, and image quality and reliability of image formation are easily maintained.

  Examples of the material constituting the first particle and the second particle as the external additive used in the present embodiment include silica, alumina, titania, barium titanate, magnesium titanate, calcium titanate, strontium titanate, and oxidation. Examples of the particles include zinc, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, inorganic oxide particles such as silica particles, titania particles, and alumina particles are preferable from the viewpoint of toner fluidity and chargeability, and particularly inorganic particles such as silica particles, titania particles, and alumina particles that have been hydrophobized. Oxide particles are preferred. The materials constituting the first particles and the second particles used in the present embodiment may be the same material or different materials.

  The hydrophobizing treatment is performed, for example, by immersing the inorganic oxide particles or the like in a hydrophobizing agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together. The amount of the hydrophobizing agent is usually about 0.5 parts by mass or more and about 10 parts by mass with respect to 100 parts by mass of the inorganic oxide particles.

  The number average particle diameter of the first particles is preferably in the range of, for example, 8 nm or more and 50 nm or less from the viewpoint of fixing to the toner particle surface and maintaining the coating state. Further, the volume average particle diameter of the second particles may be 3 times or more of the number average particle diameter of the first particles, but from the viewpoint of ease of movement, it should be in the range of 3.5 to 10 times. For example, a range of 100 nm to 400 nm is preferable.

  The coverage of the first particles with respect to the toner particles may be in the range of 90% to 150%. However, from the viewpoint of improving the fluidity of the toner particles and suppressing the influence on the image color at the time of fixing, the coverage is 100% or more and 130. % Or less is preferable. The coverage of the second particles with respect to the toner particles may be in the range of 5% or more and 50% or less. However, the viewpoint of suppressing the adhesion of the toner to the toner layer regulating member and the second particle adhesion to the photoreceptor are suppressed. From the viewpoint, it is preferably in the range of 10% to 30%.

  In addition, the shape factor SF1 of the second particles is preferably in the range of 100 to 135, and more preferably in the range of 100 to 125. When the shape factor SF1 of the second particle satisfies the above range, the particle becomes nearly circular, so that the second particle is more likely to roll on the first particle, and the surface of the toner layer regulating member is scratched. It is difficult to prevent the toner from adhering to the toner layer regulating member. As a result, the occurrence of toner drop and contamination on the image on the recording medium can be suppressed. The shape factor SF1 is obtained as follows.

First, an electron microscope image of the second particles on the toner particles is taken into a Luzex image analyzer (FT manufactured by Nireco Corporation) through a video camera, and the maximum length (ML) and projected area (A ), And for each second particle, (ML ² / A) × (π / 4) × 100 is calculated, and the average value thereof is the second particle shape factor SF1.

  The method for producing a non-magnetic one-component toner of the present embodiment includes, for example, a step of producing toner particles (toner particle production step), and a step of attaching external additives to the toner particles (external additive attachment step). Including.

  The toner particle preparation step is not particularly limited, and examples thereof include a known kneading and pulverizing method, a chemical method such as emulsion polymerization, suspension polymerization, and emulsion aggregation method. Among them, toner particles are produced by an emulsion aggregation method from the viewpoint of producing a toner having excellent storage characteristics and chargeability due to particle size distribution, shape distribution, surface property, and core-shell structure, and in terms of yield and environmental load. It is preferable.

  As the external additive attaching step, a method of adding and mixing the first particles to the toner particles and then adding and mixing the second particles, a method of adding and mixing the second particles to the toner particles, and then adding and mixing the first particles, Alternatively, a method of adding and mixing the first particles and the second particles to the toner particles may be used. In any of the above methods, the first particles and the second particles are added so that the coverage of the first particles with respect to the toner particles is in the range of 90% to 150% and the coverage of the second particles is 5% to 50%. If the amount is controlled, as described above, the non-magnetic one-component toner of this embodiment in which the first particles mainly adhere to the toner particle surfaces and the second particles adhere to the first particle surfaces can be obtained. However, in order to efficiently attach the first particles to the surface of the toner particles and to attach the second particles on the surface of the first particles, the first particles are added and mixed with the toner particles, and then the second particles are added and mixed. It is preferable to adopt the method.

  The amount of the first particles added depends on the number average particle diameter and true specific gravity of the particles to be used. For example, the range of 0.5 parts by mass or more and 10 parts by mass or less is preferable with respect to 100 parts by mass of the toner particles. The range of 1 part by mass or more and 5 parts by mass or less is more preferable. The amount of the second particles added depends on the number average particle diameter and true specific gravity of the particles used, but is preferably in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the toner particles, A range of 0.5 parts by mass or more and 2 parts by mass or less is more preferable. When the addition amount of the first particles and the second particles is out of the above range, the coverage of the first particles with respect to the toner particles is 90% to 150% and the coverage of the second particles is 5% to 50%. It may not be.

  Examples of the mixer used for addition and mixing in the external additive attaching step include known mixers such as a V-type blender, a Henschel mixer, and a Redige mixer. Examples of the external additive attaching step include a wet method in which the first particles and the second particles are added and mixed in a solvent such as water and ethanol, and a dry method in which no solvent is used.

  Hereinafter, although an Example and a comparative example are given and it demonstrates concretely from this embodiment, this embodiment is not limited to the following examples. Unless otherwise specified, “parts” and “%” represent “parts by mass” and “mass%”.

<Synthesis of polyester resin 1>
Into a heat-dried three-necked flask, 250 parts of 1,12-dodecanedicarboxylic acid and 130 parts of 1,10-decanediol and 0.15 part of tetrabutoxy titanate as a catalyst were added, and the air in the container was decompressed by a decompression operation. The mixture was further brought into an inert atmosphere with nitrogen gas, and refluxed at 160 ° C. for 10 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 200 ° C. by vacuum distillation, and the mixture was stirred for 3.0 hours to stop the vacuum distillation and air-cooled to obtain polyester resin 1.

<Preparation of polyester resin dispersion 1>
Next, 210 parts of this polyester resin 1 and 650 parts of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 90 ° C. When the polyester resin 1 was melted, the mixture was stirred at 8500 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and at the same time, diluted ammonia water was added to adjust the pH to 8.0. Subsequently, while dispersing 25 parts of an aqueous solution obtained by diluting 1.0 part of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R), emulsification dispersion was performed to prepare a polyester resin dispersion 1.

<Synthesis of polyester resin 2>
In a heat-dried three-necked flask, 90 parts of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 15 parts of ethylene glycol, 10 parts of cyclohexanediol, 90 parts of terephthalic acid, After adding 25 parts of n-dodecenyl succinic acid as a raw material and 0.04 part of tetrabutoxy titanate as a catalyst, the air in the container was decompressed by depressurization, and further an inert atmosphere with nitrogen gas. Reflux was carried out at 6 ° C. for 6 hours. Thereafter, the temperature was gradually raised to 210 ° C. by vacuum distillation, and the mixture was stirred for 12 hours to stop the vacuum distillation and air-cooled to obtain polyester resin 2.

<Preparation of polyester resin dispersion 2>
Next, 190 parts of this polyester resin 2 and 580 parts of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 90 ° C. When the polyester resin 2 was melted, the mixture was stirred at 8500 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and at the same time, diluted ammonia water was added to adjust the pH to 8.5. Then, while adding 20 parts of an aqueous solution obtained by diluting 1.0 part of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R), emulsification and dispersion were carried out to obtain polyester resin dispersion 2 (resin dispersion (2)). ) Was adjusted.

<Preparation of colorant dispersion>
Carbon black Legal 330: 99 parts (manufactured by Cabot), 15 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku: Neogen R), and 300 parts of ion-exchanged water are mixed, and a homogenizer (manufactured by IKA: Ultra) After dispersing for 10 minutes using TALAX T50), a coloring agent dispersion was obtained by applying to a circulating ultrasonic disperser (RUS 600TCVP, manufactured by Nippon Seiki Seisakusho).

<Preparation of release agent dispersion>
Mix 90 parts of Fischer-Tropsch wax FNP92 (melting temperature 92 ° C .: manufactured by Nippon Seiki Co., Ltd.), 3.6 parts of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R), and 360 parts of ion-exchanged water. The mixture was heated to 100 ° C. and sufficiently dispersed with a homogenizer (manufactured by IKA: Ultra Turrax T50), and then dispersed with a pressure discharge type gorin homogenizer to obtain a release agent dispersion.

<Preparation of toner particles>
A round stainless steel flask containing 105 parts of polyester resin dispersion 1 or 700 parts of polyester resin dispersion 2, 50.5 parts of colorant dispersion, 120 parts of release agent dispersion, and 500 parts of deionized water It was put in and mixed and dispersed with Ultra Turrax T50. Next, 0.4 part of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. Further, the flask was heated to 52 ° C. with stirring in an oil bath for heating and held for 3 hours. Then, after adjusting the pH of the system to 9.0 with a 0.5N aqueous sodium hydroxide solution, the stainless steel flask was sealed, heated to 90 ° C. while continuing stirring using a magnetic seal, and maintained for 3.5 hours. did. After completion of the reaction, the mixture was cooled, filtered, thoroughly washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 liters of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated 5 times, and No. 1 was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper, and then vacuum drying was performed for 12 hours to obtain toner particles. The volume average diameter of the toner particles was 7.2 μm.

Example 1
In Example 1, 100 parts of toner particles prepared as described above using a polyester resin dispersion and 2.2 parts of silica treated with HMDS having a number average particle size of 25 nm and aminopropyltriethoxysilane as the first particles are Henschel. After mixing with a mixer at a rotational speed of 4500 rpm for 15 minutes, 0.9 parts of HMDS-treated sol-gel silica having a volume average particle diameter of 75 nm was added as the second particle, and the rotational speed was 2500 rpm with a Henschel mixer. By mixing for 3 minutes, a non-magnetic one-component toner (1) was obtained. The coverage of the first particles with respect to the toner particles was 90% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as calculated from the above formula. Further, the number average particle size of the second particles was 3 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 108 as measured by an image analysis method by electron microscope observation.

(Example 2)
In Example 2, a nonmagnetic one-component toner (2) was obtained in the same manner as in Example 1 except that the addition amount of the first particles was changed from 2.2 parts to 4.0 parts. The coverage of the first particles with respect to the toner particles was 150% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as calculated from the above formula. The volume average particle size of the second particles was 3 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 108 as measured by an image analysis method by electron microscope observation.

(Example 3)
In Example 3, Example 1 was performed except that the addition amount of the first particles was changed from 2.2 parts to 2.7 parts and the addition amount of the second particles was changed from 0.9 parts to 2.0 parts. And a non-magnetic one-component toner (3) was obtained. The coverage of the first particles with respect to the toner particles was 110% (optimum value) as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 50% as calculated from the above formula. Further, the number average particle size of the second particles was 3 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 108 as measured by an image analysis method by electron microscope observation.

Example 4
In Example 4, a nonmagnetic one-component toner (4) was obtained in the same manner as in Example 3 except that the amount of the second particles added was changed from 0.9 part to 0.2 part. The coverage of the first particles with respect to the toner particles was 110% (optimum value) as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 5% as calculated from the above formula. The volume average particle size of the second particles was 3 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 108 as measured by an image analysis method by electron microscope observation.

(Example 5)
In Example 5, the HMSD-treated sol-gel silica having a number average particle size of 75 nm was replaced with the crosslinkable polystyrene particles having a number average particle size of 125 nm as the second particles, and the addition amount of the second particles was changed from 0.2 parts to 1.4 parts. A nonmagnetic monocomponent toner (5) was obtained in the same manner as in Example 4 except that the toner was replaced. The coverage of the first particles with respect to the toner particles was 110% as calculated by the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as calculated from the above formula. The volume average particle size of the second particles was 5 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 105 as measured by an image analysis method by electron microscope observation.

(Example 6)
In Example 6, untreated silica having a number average particle diameter of 40 nm was dispersed in an aqueous polyvinyl solution, spray-granulated and crushed, and then sieved to remove coarse powder to obtain a silica aggregate. . A nonmagnetic one-component toner (6) was obtained in the same manner as in Example 5 except that 2.5 parts of the silica aggregate treated with HMSD was used as the second particles. The coverage of the first particles with respect to the toner particles was 110% as calculated from the above formula. Further, the number average particle diameter of the second particles with respect to the toner particles was 150 nm, and the coverage of the second particles was 20% as calculated from the above formula. The volume average particle size of the second particles was 6 times the volume average particle size of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 135 as measured by an image analysis method by electron microscope observation.

(Example 7)
In Example 7, after adding polyaluminum chloride aqueous solution to polystyrene particle latex having an average particle diameter of 140 nm and stirring at 25 ° C. under nitrogen blowing, divinylbenzene was added dropwise, and stirring was continued for 10 hours. The solution was dropped, heated to 80 ° C. and held for 24 hours. Thereafter, the mixture was centrifuged to remove the supernatant, freeze-dried, and sieved to remove coarse powder to obtain crosslinkable polystyrene particle aggregates. A nonmagnetic one-component toner (7) was obtained in the same manner as in Example 5 except that 2.0 parts of this crosslinkable polystyrene particle aggregate was used as the second particles. The coverage of the first particles with respect to the toner particles was 110% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as measured by the above-described calculation method. The volume average particle size of the second particles was 8 times the volume average particle size of the first particles as measured by an image analysis method under electron microscope observation. Further, the shape factor SF1 of the second particles was 140 as measured by an image analysis method observed with an electron microscope.

(Example 8)
In Example 8, 2.5 parts of rutile titania treated with decylsilane and aminopropyltriethoxysilane having a number average particle diameter of 15 nm and 1.1 parts of 75 nm HMDS-treated sol-gel silica were added to the first particles, and rotated with a Henschel mixer. The mixture was mixed at several 3500 rpm for 10 minutes to obtain a non-magnetic one-component toner (8). The coverage of the first particles with respect to the toner particles was 100% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 25% as calculated from the above formula. Further, the number average particle diameter of the second particles was 5.4 times the volume average particle diameter of the first particles as measured by an image analysis method by electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 108 as measured by an image analysis method by electron microscope observation.

(Comparative Example 1)
In Comparative Example 1, a crosslinked polystyrene particle having a volume average particle size of 125 nm was prepared as the second particle in the same manner as in Example 5 except that 0.7 part of HMDS-treated sol-gel silica having an average particle size of 62 nm was changed to a nonmagnetic material. A one-component toner (9) was obtained. The coverage of the first particles with respect to the toner particles was 110% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as calculated from the above formula. The volume average particle diameter of the second particles was 2.5 times the volume average particle diameter of the first particles as measured by an image analysis method under electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 107 as measured by an image analysis method using an electron microscope.

(Comparative Example 2)
In Comparative Example 2, a nonmagnetic one-component toner (10) was obtained in the same manner as in Example 5 except that the amount of the first particles added was changed from 2.7 parts to 2.0 parts. The coverage of the first particles with respect to the toner particles was 85% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% as calculated from the above formula. The volume average particle size of the second particles was 5 times the volume average particle size of the first particles as measured by an image analysis method under electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 105 as measured by an image analysis method observed with an electron microscope.

(Comparative Example 3)
In Comparative Example 3, a nonmagnetic one-component toner (11) was obtained in the same manner as in Example 5 except that the addition amount of the first particles was changed from 2.7 parts to 3.6 parts. The coverage of the first particles with respect to the toner particles was 155% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 20% when calculated by the above formula and measured. The volume average particle size of the second particles was 5 times the volume average particle size of the first particles as measured by an image analysis method using an electron microscope. Furthermore, the shape factor SF1 of the second particles was 105 as measured by an image analysis method using an electron microscope.

(Comparative Example 4)
In Comparative Example 4, a nonmagnetic monocomponent toner (12) was obtained in the same manner as in Example 5 except that the amount of the second particles added was changed from 1.4 parts to 0.2 parts. The coverage of the first particles with respect to the toner particles was 110% as calculated from the above formula. Further, the coverage of the second particles with respect to the toner particles was 3.5% as calculated from the above formula. The volume average particle size of the second particles was 5 times the volume average particle size of the first particles as measured by an image analysis method using an electron microscope. Furthermore, the shape factor SF1 of the second particles was 105 as measured by an image analysis method using an electron microscope.

(Comparative Example 5)
In Comparative Example 5, a nonmagnetic one-component toner (13) was obtained in the same manner as in Example 5 except that the amount of the second particles added was changed from 1.4 parts to 3.3 parts. The coverage of the first particles with respect to the toner particles was 110% when calculated and measured from the above formula. Further, the coverage of the second particles with respect to the toner particles was 55% as calculated from the above formula. The volume average particle size of the second particles was 5 times the volume average particle size of the first particles as measured by an image analysis method under electron microscope observation. Furthermore, the shape factor SF1 of the second particles was 105 as measured by an image analysis method using an electron microscope.

<Evaluation>
(Evaluation of toner contamination and density unevenness)
The nonmagnetic one-component toner (1) of Example 1 was allowed to stand for 24 hours in an environment of 45 ° C./50% RH. Next, the non-magnetic one-component toner (1) was filled in a developing device of a modified DocuPrint 2020 manufactured by Fuji Xerox Co., Ltd., and 10,000 images with an image area ratio of 5% were printed in an environment of 32 ° C./90% RH. After printing 10,000 sheets, an entire highlight image (image density 30%) and white paper (image density 0%) were printed, and the toner stains and density unevenness seen on the image were evaluated according to the following evaluation criteria. Recycled copy paper G70 (70% waste paper pulp, 67 g / m ² basis weight, ISO whiteness 72% / Fuji Xerox Co., Ltd.) was used as the test paper. The nonmagnetic monocomponent toners (2) to (13) of Examples 2 to 8 and Comparative Examples 1 to 5 were also evaluated in the same manner. The results are summarized in Table 1.
A: No toner smear was observed. Also, the image was excellent with no uneven density.
○: No toner smearing occurred, but slight density unevenness was observed in a part of the highlight image, but it was at a level causing no practical problem.
(Triangle | delta): The toner stain | pollution | contamination generate | occur | produced only 1 to 3 places only in the blank paper image, and although the toner stain | pollution | contamination was not seen, the density unevenness was seen a little.
X: Four or more toner stains occurred on the blank paper image and the highlight image, respectively, and the density unevenness was noticeable.

(Evaluation of toner drips and dirt)
The nonmagnetic one-component toner (1) of Example 1 was allowed to stand for 24 hours in an environment of 45 ° C./50% RH. Next, the nonmagnetic one-component toner (1) was filled in a developing device of a modified DocuPrint 2020 manufactured by Fuji Xerox Co., Ltd., and 10,000 images with an image area ratio of 20% were printed in an environment of 32 ° C./90% RH. After printing, the front cover of the modified DocuPrint 2020 was opened, and a cartridge removal operation simulating cartridge replacement was performed. When removing the cartridge, wear a white cloth glove on your hand, and visually observe toner adhesion to the glove and toner drop on the periphery. In accordance with the evaluation. The nonmagnetic monocomponent toners (2) to (13) of Examples 2 to 8 and Comparative Examples 1 to 5 were also evaluated in the same manner. The results are summarized in Table 1.
(Double-circle): The toner drop and dirt which were used for the operation and the periphery were not seen.
○: Although the glove used for the operation had a slight amount of toner attached thereto, there was no occurrence of toner spilling on the periphery and the level was not problematic in practice.
△: Gloves used for the operation are clearly contaminated with toner, but there is no toner spilling on the periphery, and after work you can wear your gloves or wash your hands. It was in a state. .
X: Gloves used for the operation clearly had toner stains, and toner droplets fell on the periphery, and the surroundings had to be cleaned after the cartridge was removed.

  As described above, the volume average particle diameter of the second particles is set to be three times or more of the volume average particle diameter of the first particles, the coverage of the first particles with respect to the toner particles is 90% to 150%, and the second with respect to the toner particles. The non-magnetic one-component toners (1) to (8) of Examples 1 to 8 having a particle coverage of 5% to 50% are the volume average particle diameter of the second particles, the first particles, and the second particles. Compared with the non-magnetic one-component toners (9) to (13) of Comparative Examples 1 to 5 in which at least one of the coverage ratios of the toners does not satisfy the range of the above-described embodiment, the toner contamination of the image and the unevenness of the image density As a result, the toner drop and dirt during the cartridge replacement operation were suppressed. Further, the non-magnetic one-component toner (6) of Example 6 in which the shape factor SF1 of the second particle is 135 is more than the non-magnetic one-component toner (7) of the example in which the shape factor SF1 of the second particle is 140. Further, the toner smear of the image and the uneven density of the image were further suppressed. Further, in the nonmagnetic one-component toners (1) to (8) of Examples 1 to 8, the surface of the toner layer regulating member after the evaluation of the ground cover and the toner drips and dirt was cut out and ultrasonically cleaned in ethanol. When observed with an electron microscope, the surface was not scratched.

  12 developing roll, 14 bias power source, 16 toner scraping member, 18 toner layer regulating member, 20 stirring member, 22 housing, 24 non-magnetic one-component toner, 26a, 26b, 26c second particles, 28a, 28b, 28c, 28d First particle, 30a, 30b, 30c, 30d Toner particle, 200 Image forming device, 400 Housing, 401, 401a to 401d Electrophotographic photosensitive member, 402a to 402d Charging roll, 403 Exposure device, 404, 404a to 404d Developing device , 405a to 405d toner cartridge, 406 drive roll, 407 tension roll, 408 backup roll, 409 intermediate transfer belt, 410a to 410d primary transfer roll, 411 paper tray, 412 transfer roll, 413 secondary transfer roll, 414 constant Roll, 416 cleaning blade.

Claims (5)

Toner particles containing a colorant and a binder resin, and an external additive attached to the toner particle surface,
The external additive includes first particles and second particles having a number average particle size of 6 times or more of the number average particle size of the first particles,
The coverage of the first particles with respect to the toner particles is 90% or more and 150% or less, and the coverage of the second particles with respect to the toner particles is 5% or more and 50% or less.
The non-magnetic one-component toner, wherein the second particle has a shape factor SF1 of 135 or more and 140 or less . Non-magnetic one-component toner of claim 1 Symbol placement, wherein the binder resin is a polyester resin. Toner cartridge, characterized in that it contains non-magnetic one-component toner according to any one of claims 1-2. An electrostatic latent image formed on the surface of the image carrier is developed using the non-magnetic one-component toner according to any one of claims 1 to 2 and includes a developing unit that forms a toner image. To process cartridge. The image holding member, a charging unit that charges the surface of the image holding member, a latent image forming unit that forms an electrostatic latent image on the charged surface of the image holding member, and the electrostatic latent image. A developing unit that develops using the non-magnetic one-component toner according to any one of 2 to 2 to form a toner image, and a transfer unit that transfers the developed toner image to a recording medium. An image forming apparatus.