Non-magnetic one-component toner and image forming apparatus

Abstract

To provide a non-magnetic one-component toner with which an image with high image density and less thin layer streaks and fogging can be formed even when printing is performed on a large number of sheets.SOLUTION: A non-magnetic one-component toner includes a toner particle. The toner particle comprises a toner base particle and an external additive attached to the surface of the toner base particle. The external additive includes silica particles and fluorine-containing particles. In predetermined printing in which a standard test page image defined by ISO 19752 is printed on 1000 recording media, the content Si0 of the silica particles in the toner particle before the predetermined printing and the content Si1000D of the silica particles in the toner particle in a developing unit after the predetermined printing satisfy the formula (1) 0.5≤Si1000D / Si0≤1.0, and the content F0 of the fluorine-containing particles in the toner particle before the predetermined printing and the content F1000D of the fluorine-containing particles in the toner particle in the developing unit after the predetermined printing satisfy the formula (2) 1.0≤F1000D / F0≤1.5.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a non-magnetic single-component toner and an image forming apparatus. [Background technology]

[0002] Dry development methods include two-component development methods and one-component development methods. Two-component development methods use a two-component developer containing toner and carrier. One-component development methods use a one-component developer containing toner but not carrier. Because no carrier is used, one-component development methods have the advantage of not causing carrier deterioration or fluctuations in the mixture ratio of toner and carrier. One-component development methods also have the advantage of making image forming apparatuses easier to maintain and more compact. For this reason, various one-component developers for use in one-component development methods are being studied. An external additive is added to the toner base particles of the positively charged toner for non-magnetic one-component development described in Patent Document 1. This external additive has an average particle diameter of 200 nm to 1000 nm and an electrical resistivity of 1×10 15 It contains negatively charged resin particles of Ω·cm or less, silica with an average particle size of 50nm to 300nm, silica with an average particle size of 5nm or more but less than 50nm, and polytetrafluoroethylene particles with an average particle size of 100nm to 1000nm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-180910 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the amount of external additives contained in toner particles in an image forming apparatus gradually changes as a result of printing a large number of sheets. The positively charged toner for non-magnetic one-component development described in Patent Document 1 does not take into consideration this change in the amount of external additives, and is therefore insufficient in terms of stably forming high-quality images when a large number of sheets are printed. Specifically, the toner described in Patent Document 1 is insufficient in terms of forming images with high image density and minimal thin layer streaks and fog when a large number of sheets are printed.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a non-magnetic single-component toner and an image forming apparatus that can form images with high image density and little thin layer streaks and fog, even when printing a large number of sheets. [Means for solving the problem]

[0006] The non-magnetic single-component toner according to the present invention includes toner particles. The toner particles include toner base particles and an external additive attached to the surface of the toner base particles. The external additive includes silica particles and fluorine-containing particles. In a predetermined printing process in which a standard test page image defined in ISO 19752 is printed on 1,000 sheets of recording medium, the silica particle content Si0 in the toner particles before the predetermined printing and the silica particle content Si in the toner particles in a developing unit after the predetermined printing are calculated. 1000D The content rate F0 of the fluorine-containing particles in the toner particles before the predetermined printing and the content rate F of the fluorine-containing particles in the toner particles in the developing unit after the predetermined printing satisfy the following formula (1): 1000D and satisfy the following formula (2). 0.5≦Si 1000D / Si0≦1.0 (1) 1.0≦F 1000D / F0≦1.5 (2)

[0007] The image forming apparatus according to the present invention includes an image carrier and a developing unit that supplies non-magnetic one-component toner to an electrostatic latent image formed on the surface of the image carrier. The non-magnetic one-component toner includes toner particles. The toner particles include toner base particles and an external additive attached to the surface of the toner base particles. The external additive includes silica particles and fluorine-containing particles. In a predetermined printing operation in which a standard test page image defined in ISO 19752 is printed on 1,000 sheets of recording medium, the silica particle content Si0 in the toner particles before the predetermined printing and the silica particle content Si in the toner particles in the developing unit after the predetermined printing are calculated. 1000D The content rate F0 of the fluorine-containing particles in the toner particles before the predetermined printing and the content rate F of the fluorine-containing particles in the toner particles in the developing unit after the predetermined printing satisfy the following formula (1): 1000D and satisfy the following formula (2). 0.5≦Si 1000D / Si0≦1.0 (1) 1.0≦F 1000D / F0≦1.5 (2) [Effects of the Invention]

[0008] The non-magnetic single-component toner and image forming apparatus according to the present invention can form images with high image density and little thin layer streaks and fog, even when printing a large number of sheets. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 10 is a diagram showing an image forming apparatus according to a second embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of the image carrier and the developing unit shown in FIG. [Figure 3] FIG. 2 is an enlarged view of the image carrier and cleaning unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described. First, the terms used in this specification will be described. A non-magnetic single-component toner is an aggregate (for example, powder) of toner particles. An external additive is an aggregate (for example, powder) of external additive particles. Unless otherwise specified, evaluation results (for example, values ​​indicating shape and physical properties) of powders (for example, powders of toner particles and powders of external additive particles) are the number averages of values ​​measured for each of a considerable number of particles selected from the powder. Unless otherwise specified, the softening point (Tm) is a value measured using a high-speed flow tester ("CFT-500D" manufactured by Shimadzu Corporation). The volume median diameter (D 50 ) is the median diameter measured using a laser diffraction / scattering particle size distribution analyzer (e.g., Beckman Coulter's "Multisizer 3"). Unless otherwise specified, the number-average primary particle diameter of a powder is the number average of the circle-equivalent diameters of primary particles (Heywood diameter: the diameter of a circle having the same area as the projected area of ​​a primary particle) measured using a scanning electron microscope. Unless otherwise specified, the "major component" of a material refers to the component that is contained in the largest amount in the material by mass. The strength of hydrophobicity can be expressed, for example, by the contact angle of a water droplet (ease of wetting with water). The larger the contact angle of the water droplet, the stronger the hydrophobicity. Each component described in this specification may be used alone or in combination of two or more. The terms used in this specification have been explained above.

[0011] [First embodiment: non-magnetic single-component toner] The first embodiment of the present invention relates to a non-magnetic one-component toner. The non-magnetic one-component toner of the present invention includes toner particles. The toner particles include toner base particles and external additives adhered to the surfaces of the toner base particles. The external additives include silica particles and fluorine-containing particles. In a predetermined printing process in which a standard test page image defined in ISO 19752 is printed on 1,000 sheets of recording medium, the silica particle content Si0 of the toner particles before the predetermined printing and the silica particle content Si of the toner particles in the developing unit after the predetermined printing are measured. 1000D The formula (1) "0.5≦Si 1000D / Si0≦1.0". The content of fluorine-containing particles in the toner particles before a predetermined printing F0 and the content of fluorine-containing particles in the toner particles in the developing section after a predetermined printing F 1000D And, the formula (2) "1.0 ≦ F 1000D / F0≦1.5”.

[0012] Hereinafter, "non-magnetic one-component toner" may be referred to as "toner." "The content of silica particles in toner particles before a predetermined printing period Si0" may be referred to as "initial silica content Si0." "The content of silica particles in toner particles in the developing section after a predetermined printing period Si 1000D " and "Developing section durability silica content Si 1000D "The content F0 of fluorine-containing particles in toner particles before a predetermined printing" is sometimes referred to as "initial fluorine content F0." "The content F0 of fluorine-containing particles in toner particles in the developing section after a predetermined printing" is sometimes referred to as "initial fluorine content F0." 1000D " to "development zone durability fluorine content F 1000D " in formula (1) 1000D / Si0" is the "ratio (development section durability silica content Si 1000D The "F / initial silica content Si0" in formula (2) is sometimes written as "F 1000D / F0" and "Ratio (development section durability fluorine content F 1000D / initial fluorine content F0).

[0013] By virtue of the above-described configuration, the toner of the present invention can form images with high image density and little thin layer streaks or fog, even when a large number of sheets are printed. The reason for this is presumed to be as follows. This will be explained below with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing an image forming apparatus 1 according to a second embodiment, which will be described later. FIG. 2 is an enlarged view of the image carrier 23 and the developing unit 22 shown in FIG. 1.

[0014] To facilitate understanding, an overview of the developing unit 22, which employs a non-magnetic single-component development method, will first be described. As shown in FIG. 1, the image forming apparatus 1 includes the developing unit 22 and an image carrier 23. As shown in FIG. 2, the developing unit 22 includes a storage frame 210, a supply roller 220, a developing roller 230, and a regulating blade 240. The storage frame 210 stores toner T therein. The supply roller 220 supplies the toner T stored in the storage frame 210 to the developing roller 230. The developing roller 230 holds the toner T supplied from the supply roller 220 on its surface (circumferential surface) 230a in the form of a toner layer (a so-called thin toner layer). At a nip N2 between the regulating blade 240 and the developing roller 230, the regulating blade 240 regulates the thickness of the toner layer held on the surface 230a of the developing roller 230. Regulating the thickness of the toner layer means adjusting the thickness of the toner layer to a predetermined uniform value. After the thickness is regulated, the toner T contained in the toner layer is supplied from the surface 230a of the developing roller 230 to the electrostatic latent image formed on the surface (circumferential surface) 23a of the image carrier 23. The electrostatic latent image is then developed into a toner image. The above has described an overview of the developing unit 22 that employs a non-magnetic one-component development method.

[0015] Here, at the nip N2, the toner T held by the developing roller 230 may adhere and stick to the regulating blade 240. When the thickness of the toner layer is regulated by the regulating blade 240 to which the toner T has stuck, the thickness of the toner layer becomes uneven. As a result, streaks (thin layer streaks) appear in the formed image.

[0016] Therefore, in the present invention, the external additives contained in the toner particles include fluorine-containing particles. Some of the fluorine-containing particles detached from the toner base particles in the developing unit 22 adhere to the regulating blade 240. The adhered fluorine-containing particles make it difficult for the toner T to adhere to the regulating blade 240. As a result, it is possible to suppress the occurrence of thin layer streaks in the formed image.

[0017] On the other hand, if an excessive amount of fluorine-containing particles adheres to the regulating blade 240, the regulating blade 240 will not be able to adequately regulate the thickness of the toner layer. Therefore, in the present invention, the external additive contained in the toner particles contains silica particles. The silica particles detached from the toner base particles in the developing unit 22 scrape off the fluorine-containing particles adhered to the regulating blade 240. This keeps the amount of fluorine-containing particles adhered to the regulating blade 240 appropriate.

[0018] Here, as printing progresses using the image forming apparatus 1 filled with toner T, the content ratios of fluorine-containing particles and silica particles change in the developing unit 22. For example, when fluorine-containing particles detached from the toner base particles remain in the developing unit 22, the content ratio of fluorine-containing particles in the toner particles in the developing unit 22 increases. On the other hand, when fluorine-containing particles detached from the toner base particles adhere to the regulating blade 240, the content ratio of fluorine-containing particles in the toner particles in the developing unit 22 decreases. Furthermore, when fluorine-containing particles detached from the toner base particles are developed together with toner T from the developing roller 230 onto the image carrier 23, the content ratio of fluorine-containing particles in the toner particles in the developing unit 22 decreases. Furthermore, when silica particles detached from the toner base particles remain in the developing unit 22, the content ratio of silica particles in the toner particles increases. On the other hand, when silica particles detached from the toner base particles are developed together with toner T from the developing roller 230 onto the image carrier 23, the content ratio of silica particles in the toner particles in the developing unit 22 decreases. As described above, as printing continues, the content ratios of fluorine-containing particles and silica particles change in the developing unit 22. Therefore, controlling the amount of change in the content ratios of fluorine-containing particles and silica particles in the developing unit 22 during printing is effective for stable toner layer formation and stable image formation during printing.

[0019] Therefore, the toner T of the present invention satisfies the formula (2) "1.0≦F 1000D / F0≦1.5" is satisfied. 1000DIf the initial fluorine content F0) is 1.0 or more, a sufficient amount of fluorine-containing particles remains in the developing unit 22 even after a predetermined amount of printing. Since a sufficient amount of fluorine-containing particles adheres to the regulating blade 240, the toner T is less likely to adhere to the regulating blade 240. As a result, the occurrence of thin layer streaks in the formed image can be suppressed.

[0020] On the other hand, if an excessive amount of fluorine-containing particles adheres to the regulating blade 240, the regulating blade 240 cannot sufficiently regulate the thickness of the toner layer, and the toner layer becomes thick. If the toner layer is thick, only the surface of the toner layer is charged, and it is difficult to charge the entire toner layer uniformly. As a result, fogging occurs in the formed image. Therefore, in the present invention, the ratio of the toner T (development section durability fluorine content F 1000D / initial fluorine content F0) is 1.5 or less. 1000D If the initial fluorine content F0) is 1.5 or less, the amount of fluorine-containing particles in the developing unit 22 will not become excessive after a predetermined amount of printing. Since an excessive amount of fluorine-containing particles will not adhere to the regulating blade 240, the occurrence of fogging in the formed image can be suppressed.

[0021] Furthermore, the toner T of the present invention satisfies the formula (1) "0.5≦Si 1000D / Si0≦1.0" is satisfied. 1000D If the ratio of the toner T to the initial silica content Si0 exceeds 1.0, the silica particles in the developing section will be excessive after a predetermined number of prints. The excessive amount of silica particles will scrape off excessive amounts of the fluorine-containing particles adhering to the regulating blade 240. As a result, the toner T will adhere to the regulating blade 240, causing thin layer streaks in the formed image. Therefore, in the present invention, the ratio of the toner T (the development section durability silica content Si 1000D The initial silica content (Si0) is set to 1.0 or less, which can prevent thin layer streaks from occurring in the formed image.

[0022] In addition to scraping off the fluorine-containing particles adhering to the regulating blade 240, the silica particles also contribute to the charging of the toner particles. 1000DIf the ratio of the toner T (the development section durability silica content Si / initial silica content Si0) is less than 0.5, the amount of silica particles in the development section will be insufficient after a predetermined number of prints. As a result, the toner particles cannot be charged to the desired value, and the image density of the formed image will decrease. In addition, since the toner particles cannot be charged to the desired value, the toner layer on the development roller 230 will be excessively thin, and thin layer streaks will occur in the formed image. Therefore, in the present invention, the ratio of the toner T (the development section durability silica content Si 1000D The initial silica content (Si0) is set to 0.5 or more, which makes it possible to form an image with high image density and to prevent thin layer streaks from occurring in the formed image.

[0023] The reason why the toner of the present invention can form images with high image density and little thin layer streaks and fog even when a large number of sheets are printed has been explained above with reference to FIGS.

[0024] The toner of the present invention is particularly suitable for use as a cartridge-type toner (non-magnetic single-component toner) that does not require replenishment toner. In cartridge-type toner that does not require replenishment toner, small toner particles with high chargeability are preferentially developed over large toner particles with low chargeability. Therefore, the particle size distribution of the toner at the initial stage (e.g., before a predetermined number of prints) differs from the particle size distribution of the toner after printing (e.g., after a predetermined number of prints). Different particle sizes of toner particles also result in different amounts of external additives adhering to the toner base particles. The smaller the particle size of the toner particles, the larger the specific surface area per unit weight of the toner particles, and the greater the amount of external additives that can adhere to the toner base particles. On the other hand, as printing progresses, the particle size of the toner particles increases, the specific surface area per unit weight of the toner particles decreases, and the amount of external additives that can adhere to the toner base particles decreases. When the amount of external additives adhering to the toner base particles decreases, the toner's adhesive force to the regulating blade increases, making the toner more likely to adhere to the regulating blade. Therefore, cartridge-type toners that do not require replenishment are particularly prone to thin layer streaks in formed images. However, as already mentioned, the toner of the present invention can suppress the occurrence of thin layer streaks in formed images. Furthermore, by satisfying formulas (1) and (2), the toner of the present invention can control the difference in the amount of external additive attached to the toner base particles initially (e.g., before a predetermined printing) and after printing (e.g., after a predetermined printing). Therefore, the toner of the present invention can be particularly suitably used as a cartridge-type toner that does not require replenishment toner.

[0025] Furthermore, the toner of the present invention is particularly suitable for use as a toner containing a release agent. The aforementioned thin streaks tend to occur particularly when an image is formed using a toner containing a release agent. To reduce the size and cost of the fixing unit of an image forming apparatus, a fixing unit that does not include a fixing oil application mechanism or that applies a reduced amount of fixing oil may be used. To suppress offset to such a fixing unit, a release agent may be incorporated into the toner. However, if a large amount of release agent is incorporated into the toner, the amount of release agent on the toner surface increases, making the toner more likely to adhere to the regulating blade due to mechanical and thermal effects. For these reasons, thin streaks tend to occur particularly when an image is formed using a toner containing a release agent. However, as already mentioned, the toner of the present invention can suppress the occurrence of thin streaks in the formed image. Therefore, the toner of the present invention can be particularly suitable for use as a toner containing a release agent.

[0026] <Equation (3) and Equation (4)> Next, the formulas (3) and (4) will be explained. The silica particle content Si0 in the toner particles before the predetermined printing and the silica particle content Si in the toner particles in the cleaning section after the predetermined printing are 1000C This means that the formula (3) "0.7≦Si 1000C It is preferable that the content F0 of fluorine-containing particles in the toner particles before the predetermined printing and the content F1 of fluorine-containing particles in the toner particles in the cleaning section after the predetermined printing are satisfied. 1000C This means that the formula (4) "2.0≦F 1000C It is preferable that " / F0≦2.5" is satisfied.

[0027] Hereinafter, the content of silica particles in the toner particles in the cleaning section after a predetermined printing is referred to as "Si 1000C ", "Cleaning section durability silica content Si 1000C " Also, "Si" in formula (3) 1000C / Si0" is the "ratio (cleaning part durability silica content Si 1000C / initial silica content Si0)" and "content F of fluorine-containing particles in toner particles in the cleaning section after a specified printing 1000C ", "Cleaning part durability fluorine content F 1000C " Also, "F" in formula (4) 1000C / F0" and "Ratio (Cleaning part durability fluorine content F 1000C / initial fluorine content F0).

[0028] To facilitate understanding, the cleaning unit 24 will be outlined with reference to FIGS. 1 and 3. FIG. 3 is an enlarged view of the image carrier 23 and the cleaning unit 24 shown in FIG. 1. As shown in FIG. 1, the image forming apparatus 1 includes the cleaning unit 24 in addition to the image carrier 23. The cleaning unit 24 includes a cleaning housing 50 and a cleaning member 51. As already described, toner T is supplied from the surface 230a of the developing roller 230 to the electrostatic latent image formed on the surface 23a of the image carrier 23. The toner T is then transferred from the image carrier 23 to the recording medium P. After transfer, the toner T remaining on the surface 23a of the image carrier 23 is removed by the cleaning member 51, which is pressed against the surface 23a of the image carrier 23. The cleaning housing 50 collects the toner T removed by the cleaning member 51 within itself. The cleaning unit 24 has been outlined above with reference to FIGS. 1 and 3.

[0029] Continuing with particular reference to FIG. 3, formulas (3) and (4) will be further explained. As printing progresses using the image forming apparatus 1 filled with toner T, the content ratios of fluorine-containing particles and silica particles change in the cleaning unit 24. For example, if a large amount of fluorine-containing particles detach from the toner base particles on the image carrier 23 is present, a large amount of fluorine-containing particles are collected in the cleaning unit 24 from the surface 23a of the image carrier 23. As a result, the content ratio of fluorine-containing particles in the toner particles in the cleaning unit 24 increases. Furthermore, if a small amount of silica particles detach from the toner base particles on the image carrier 23 is present, a small amount of silica particles are collected in the cleaning unit 24 from the surface 23a of the image carrier 23. Furthermore, if the silica particles detached from the toner base particles are transferred from the image carrier 23 to the recording medium P, a small amount of silica particles are collected in the cleaning unit 24 from the surface 23a of the image carrier 23. As a result, the content ratio of silica particles in the toner particles in the cleaning unit 24 decreases. As described above, as printing continues, the content ratios of fluorine-containing particles and silica particles change in the cleaning unit 24. Therefore, controlling the amount of change in the content ratios of fluorine-containing particles and silica particles in the cleaning unit 24 during printing is effective for stable toner layer formation and stable image formation during printing.

[0030] Here, drum filming may occur when toner T adheres and sticks to the surface 23a of the image carrier 23. When drum filming occurs, white spots may appear in the formed image. The ratio of formula (4) (cleaning section durable fluorine content F 1000C If the initial fluorine content F0) is 2.0 or more, a sufficient amount of fluorine-containing particles will be present in the cleaning unit 24 after a predetermined number of prints. Furthermore, a sufficient amount of fluorine-containing particles will also be present on the surface 23a of the image carrier 23 before it is collected in the cleaning unit 24. The fluorine-containing particles present on the surface 23a of the image carrier 23 reduce the surface energy of the image carrier 23, making it difficult for the toner T to adhere to the image carrier 23. As a result, drum filming is less likely to occur, and white spots in the formed image due to drum filming can be suppressed.

[0031] On the other hand, if an excessive amount of fluorine-containing particles is present on the surface 23a of the image carrier 23, the charge potential of the image carrier 23 does not rise to a desired value, and fog may occur in the formed image. 1000C If the initial fluorine content F0) is 2.5 or less, an appropriate amount of fluorine-containing particles will be present in the cleaning unit 24 after a predetermined amount of printing, and ultimately on the surface 23a of the image carrier 23. As a result, the charging potential of the image carrier 23 can be increased to a desired value, and the occurrence of fogging in the formed image can be suppressed.

[0032] On the other hand, if an excessive amount of silica particles is present on the surface 23a of the image carrier 23, the fluorine-containing particles present on the surface 23a of the image carrier 23 may be excessively scraped off. 1000C If the initial silica content Si0) is 0.9 or less, an appropriate amount of silica particles will remain in the cleaning unit 24 and, by extension, on the surface 23a of the image carrier 23, even after a predetermined amount of printing. The appropriate amount of silica particles will adequately scrape off the fluorine-containing particles present on the surface 23a of the image carrier 23. As a result, the amount of fluorine-containing particles present on the surface 23a of the image carrier 23 will be maintained at an appropriate level, making it difficult for the toner T to adhere to the image carrier 23. As a result, drum filming is less likely to occur, and white spots in the formed image due to drum filming can be suppressed.

[0033] In addition, the ratio of formula (3) (cleaning section durability silica content Si 1000C If the initial silica content Si0) is 0.7 or more, the toner particles will contain a sufficient amount of silica particles even after a predetermined printing. Because silica particles contribute to the charging of the toner particles, toner particles containing a sufficient amount of silica particles will be charged to a desired value. As a result, an image with high image density can be formed. Formulas (3) and (4) have been described above, with particular reference to FIG. 3.

[0034] In order to balance the amount of fluorine-containing particles adhering to the regulating blade or image carrier and the amount of fluorine-containing particles scraped off by the silica particles, the ratio Si0 / F0 of the initial silica content Si0 to the initial fluorine content F0 is preferably 2.5 or more and 5.0 or less, and more preferably 2.5 or more and 3.5 or less.

[0035] In order to balance the amount of fluorine-containing particles adhering to the regulating blade and the amount of fluorine-containing particles scraped off by silica particles, the development section durability fluorine content F 1000D Durability of the developing section silica content Si 1000D The ratio of Si 1000D / F 1000D is preferably 1.5 or more and 3.0 or less, and more preferably 1.7 or more and 2.7 or less.

[0036] In order to balance the amount of fluorine-containing particles adhering to the image carrier and the amount of fluorine-containing particles scraped off by silica particles, the cleaning unit durability fluorine content F 1000C Cleaning part durability silica content Si 1000C The ratio of Si 1000C / F 1000C is preferably 1.0 or more and 2.0 or less, and more preferably 0.9 or more and 1.8 or less.

[0037] <Measurement method for specified printing and each content> Next, the predetermined printing and the method for measuring each content shown in formulas (1) to (4) will be described. In this specification, "predetermined printing" is defined as printing a standard test page image defined in ISO19752 on 1000 sheets of recording medium. The standard test page image defined in ISO19752 is a monochrome image used to test the number of pages that can be printed by a monochrome printer. The predetermined printing is carried out, for example, using an image forming apparatus to be filled with the toner of the present invention. The initial silica content Si0, the initial fluorine content F0, and the development section durability silica content Si 1000D , development zone durability fluorine content F 1000D , cleaning part durability silica content Si 1000C, and cleaning part durability fluorine content F 1000C is measured in a predetermined print using the toner (in other words, by performing a predetermined print test on the toner).

[0038] The initial silica content Si0 and the initial fluorine content F0 are measured using toner before a predetermined printing (for example, toner T before being filled into the developing unit 22 shown in FIG. 2). 1000D , and the development zone durability fluorine content F 1000D In the measurement, the toner in the developing unit after a predetermined printing is measured (for example, the toner T present inside the storage frame 210 of the developing unit 22 shown in FIG. 2, more specifically, the toner T present inside the storage frame 210 of the developing unit 22 shown in FIG. 2 and below the developing roller 230). 1000C , and cleaning part durability fluorine content F 1000C In the measurement, the toner in the cleaning unit after a predetermined printing is the toner (for example, the toner T present inside the cleaning housing 50 provided in the cleaning unit 24 shown in Figure 3, more specifically, the toner T present inside the cleaning housing 50 provided in the cleaning unit 24 shown in Figure 3 and below the cleaning member 51) is the measurement target.

[0039] Fluorescent X-ray analysis is performed on the above-mentioned measurement objects (more specifically, the toner before the specified printing, the toner in the development unit after the specified printing, and the toner in the cleaning unit after the specified printing), and a fluorescent X-ray spectrum containing peaks attributable to the measurement elements (Si and F) is obtained. The X-ray intensity of the peak attributable to the measurement element Si in the obtained fluorescent X-ray spectrum is converted to the silica particle content (unit: mass%) in the toner particles. The X-ray intensity of the peak attributable to the measurement element F in the fluorescent X-ray spectrum is converted to the fluorine-containing particle content (unit: mass%) in the toner particles. In this way, the silica particle content in the toner particles and the fluorine-containing particle content in the toner particles are determined for the above-mentioned measurement objects.

[0040] <Toner particles> The toner particles comprise toner base particles and an external additive. The external additive is attached to the surface of the toner base particles. The toner base particles may be non-encapsulated toner particles that do not have a shell layer. Alternatively, the toner base particles may be encapsulated toner particles that include a toner core and a shell layer that covers the toner core. The toner particles do not contain magnetic powder and are used as a toner (i.e., a non-magnetic one-component toner) without being mixed with a carrier. A toner containing toner particles is suitably used, for example, as a positively charged toner for developing electrostatic latent images. In the following description of toner particles, the content ratio and amount refer to the content ratio and amount before a predetermined printing, respectively.

[0041] <External additives> The external additive includes silica particles and fluorine-containing particles. The external additive may include only fluorine-containing particles and silica particles, or may further include particles other than fluorine-containing particles and silica particles (hereinafter, sometimes referred to as "other external additive particles").

[0042] (Fluorine-containing particles) The fluorine-containing particles have fluorine atoms. Examples of the fluorine-containing particles include fluororesin particles. The fluororesin particles contain a fluororesin. The content of the fluororesin in the fluororesin particles is preferably 80% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass.

[0043] Examples of fluororesins include polytetrafluoroethylene (PTFE), perfluoroalkoxy fluororesins, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-n-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-ethylene copolymers, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymers, and tetrafluoroethylene-perfluoroalkoxyethylene copolymers. PTFE is preferred as the fluororesin.

[0044] Ratio (development section durability fluorine content F 1000D / Initial fluorine content F0) and ratio (Cleaning part durable fluorine content F 1000C The number-average primary particle diameter of the fluorine-containing particles is preferably 100 nm or more and 300 nm or less, because this makes it easier to adjust the initial fluorine content (F0) within a desired range. Furthermore, if the number-average primary particle diameter of the fluorine-containing particles is 100 nm or more, the fluorine-containing particles can be prevented from being embedded in the toner base particles. On the other hand, if the number-average primary particle diameter of the fluorine-containing particles is 300 nm or less, the amount of fluorine-containing particles detached from the toner base particles can be optimized.

[0045] When the fluorine-containing particles are fluororesin particles, emulsion polymerization is a preferred method for preparing the fluororesin particles. The fluororesin particles obtained by emulsion polymerization are nearly spherical, making them suitable as external additives for toner. Commercially available fluororesin particles may also be used. Examples of such commercially available products include KTL-500F (Kitamura Corporation, number average primary particle diameter 300 nm), Lubron (registered trademark) L2 (Daikin Industries, Ltd., number average primary particle diameter 300 nm), Lubron (registered trademark) L5 (Daikin Industries, Ltd., number average primary particle diameter 200 nm), Fluon Lubricant L170J (Asahi ICI Fluoropolymers Corporation, number average primary particle diameter 100 nm), and Fluon Lube. Examples of such polymers include Lycant L172J (manufactured by Asahi ICI Fluoropolymers Co., Ltd., number average primary particle diameter 0.1 μm), MP-1100 (manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd., number average primary particle diameter 200 nm), MP-1200 (manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd., number average primary particle diameter 300 nm), and TLP-10F-1 (manufactured by Mitsui-Chemours Fluoroproducts Co., Ltd., number average primary particle diameter 200 nm).

[0046] Ratio (development section durability fluorine content F 1000D / Initial fluorine content F0) and ratio (Cleaning part durable fluorine content F 1000CSince it is easy to adjust the initial fluorine content F) within a desired range, the content of the fluorine-containing particles before the predetermined printing is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.3 parts by mass or more and 1.0 part by mass or less, relative to 100.0 parts by mass of the toner base particles.

[0047] (silica particles) The silica particles impart fluidity to the toner particles. As the silica particles, silica particles that have been subjected to a surface treatment to impart one or both of positive chargeability and hydrophobicity are preferred. The ratio (development section durability silica content Si 1000D / Initial silica content Si0) and ratio (Cleaning part durability silica content Si 1000C Because it is easy to adjust the initial silica content (SiO) within the desired range, the number-average primary particle diameter of the silica particles is preferably 10 nm or more and 45 nm or less, and more preferably 12 nm or more and 40 nm or less. Furthermore, if the number-average primary particle diameter of the silica particles is 10 nm or more, the silica particles can be prevented from being embedded in the toner base particles. On the other hand, if the number-average primary particle diameter of the silica particles is 40 nm or less, the silica particles are less likely to detach from the toner base particles.

[0048] Ratio (development section durability silica content Si 1000D / Initial silica content Si0) and ratio (Cleaning part durability silica content Si 1000C Since it is easy to adjust the initial silica content Si0) within a desired range, the content of silica particles before a predetermined printing is preferably 0.1 parts by mass or more and 5.0 parts by mass or less, more preferably 0.5 parts by mass or more and 3.0 parts by mass or less, and even more preferably 1.5 parts by mass or more and 2.5 parts by mass or less, relative to 100.0 parts by mass of the toner base particles.

[0049] In order to balance the amount of fluorine-containing particles adhering to the regulating blade or image carrier and the amount of fluorine-containing particles scraped off by the silica particles, the ratio WSi / WF of the content WF of fluorine-containing particles per 100.0 parts by mass of toner base particles before the specified printing to the content WSi of silica particles per 100.0 parts by mass of toner base particles before the specified printing is preferably 2.5 or more and 5.0 or less, and more preferably 2.5 or more and 3.5 or less.

[0050] (Other external additive particles) Examples of other external additive particles include particles of metal oxides (specifically, alumina, magnesium oxide, zinc oxide, etc.), particles of organic acid compounds such as fatty acid metal salts (specifically, zinc stearate, etc.), and resin particles. However, the external additive does not necessarily contain resin particles other than the above-mentioned fluororesin particles.

[0051] <Toner base particles> The toner base particles contain, for example, a binder resin as a main component. The toner base particles may further contain an internal additive (for example, at least one of a colorant, a release agent, a charge control agent, and other additives) as needed. Methods for producing the toner base particles include a pulverization method and an aggregation method, with the pulverization method being preferred.

[0052] (binder resin) From the viewpoint of providing a toner with excellent low-temperature fixability, the toner base particles preferably contain a thermoplastic resin as a binder resin, and more preferably contain the thermoplastic resin in a proportion of 85% by mass or more of the total binder resin. Examples of thermoplastic resins include styrene resins, acrylic ester resins, olefin resins (e.g., polyethylene resins and polypropylene resins), vinyl resins (e.g., vinyl chloride resins, polyvinyl alcohol, vinyl ether resins, and N-vinyl resins), polyester resins, polyamide resins, and urethane resins. Copolymers of these resins, i.e., copolymers in which any repeating unit is introduced into the above-mentioned resins (e.g., styrene-acrylic ester resins and styrene-butadiene resins), can also be used as binder resins.

[0053] The content of the binder resin in the toner base particles is preferably 60% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 90% by mass or less.

[0054] From the viewpoint of improving the low-temperature fixability of the toner, polyester resins are preferred as binder resins. Polyester resins are obtained by polycondensation of one or more polyhydric alcohols and one or more polycarboxylic acids. Examples of alcohols used to synthesize polyester resins include dihydric alcohols (e.g., diol compounds and bisphenol compounds) and trivalent or higher alcohols. Examples of carboxylic acids used to synthesize polyester resins include divalent carboxylic acids and trivalent or higher carboxylic acids. Note that instead of polycarboxylic acids, polycarboxylic acid derivatives capable of forming ester bonds by polycondensation (e.g., polycarboxylic acid anhydrides and polycarboxylic acid halides) may be used.

[0055] Examples of diol compounds include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4-diol, 1,5-pentanediol, 2-pentene-1,5-diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, 1,4-benzenediol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0056] Examples of bisphenol compounds include bisphenol A, hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A (for example, polyoxyethylene (2,2)-2,2-bis(4-hydroxyphenyl)propane), and propylene oxide adducts of bisphenol A.

[0057] Examples of trihydric or higher alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.

[0058] Examples of dicarboxylic acids include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, succinic acid, alkylsuccinic acids (more specifically, n-butylsuccinic acid, isobutylsuccinic acid, n-octylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid), and alkenylsuccinic acids (more specifically, n-butenylsuccinic acid, isobutenylsuccinic acid, n-octenylsuccinic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid).

[0059] Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxylpropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empol trimer acid.

[0060] The polyester resin is preferably a condensation polymer of bisphenol A ethylene oxide adduct, terephthalic acid, and trimellitic anhydride, and more preferably a condensation polymer of polyoxyethylene(2,2)-2,2-bis(4-hydroxyphenyl)propane, terephthalic acid, and trimellitic anhydride.

[0061] (coloring agent) As the colorant, a known pigment or dye can be used in accordance with the color of the toner. From the viewpoint of forming a high-quality image using the toner, the content of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0062] The toner base particles may contain a black colorant. Examples of black colorants include carbon black. The black colorant may also be a colorant toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

[0063] The toner base particles may contain color colorants, such as yellow colorants, magenta colorants, and cyan colorants.

[0064] The yellow colorant may be, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds. Examples of the yellow colorant include CI Pigment Yellow (3, 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, and 194), Naphthol Yellow S, Hansa Yellow G, and CI Vat Yellow.

[0065] Examples of magenta colorants that can be used include one or more compounds selected from the group consisting of condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Examples of magenta colorants include CI Pigment Red (2, 3, 5, 6, 7, 19, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254).

[0066] The cyan colorant may be, for example, one or more compounds selected from the group consisting of copper phthalocyanine compounds, anthraquinone compounds, and basic dye lake compounds, including, for example, CI Pigment Blue (1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66), phthalocyanine blue, CI Vat Blue, and CI Acid Blue.

[0067] (mold release agent) The release agent is used, for example, for the purpose of imparting offset resistance to the toner. From the viewpoint of imparting sufficient offset resistance to the toner, the content of the release agent is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0068] Examples of release agents include aliphatic hydrocarbon waxes, oxidized aliphatic hydrocarbon waxes, vegetable waxes, animal waxes, mineral waxes, ester waxes primarily composed of fatty acid esters, and waxes in which fatty acid esters have been partially or completely deoxidized. Examples of aliphatic hydrocarbon waxes include low-molecular-weight polyethylene, low-molecular-weight polypropylene, polyolefin copolymers, polyolefin waxes, microcrystalline waxes, paraffin waxes, and Fischer-Tropsch waxes. Examples of oxidized aliphatic hydrocarbon waxes include oxidized polyethylene waxes and block copolymers of oxidized polyethylene waxes. Examples of vegetable waxes include candelilla wax, carnauba wax, Japan wax, jojoba wax, and rice wax. Examples of animal waxes include beeswax, lanolin, and spermaceti. Examples of mineral waxes include ozokerite, ceresin, and petrolatum. Examples of ester waxes primarily composed of fatty acid esters include Montan acid ester wax and castor wax. Examples of waxes in which fatty acid esters have been partially or completely deoxidized include deoxidized carnauba wax. As the release agent, carnauba wax is preferred.

[0069] When the toner base particles contain a release agent, a compatibilizer may be added to the toner base particles in order to improve the compatibility between the binder resin and the release agent.

[0070] (charge control agent) Charge control agents are used, for example, for the purpose of providing a toner having excellent charge stability or excellent charge rise characteristics. The charge rise characteristics of a toner are an index of whether the toner can be charged to a predetermined charge level in a short period of time. By incorporating a positively chargeable charge control agent into the toner base particles, the cationic nature of the toner base particles can be strengthened.

[0071] Examples of positively chargeable charge control agents include azine compounds, direct dyes, acid dyes, alkoxylated amines, alkylamides, quaternary ammonium salts, and resins containing quaternary ammonium cation groups. Quaternary ammonium salts are preferred as charge control agents.

[0072] From the viewpoint of obtaining a toner having excellent charge stability, the content of the charge control agent is preferably 0.1 to 30 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the binder resin.

[0073] <Toner manufacturing method> The toner can be produced, for example, by a production method including a step of preparing toner base particles and a step of adding external additives.

[0074] (Toner base particle preparation process) In the toner base particle preparation step, the toner base particles are prepared by, for example, an aggregation method or a pulverization method.

[0075] The aggregation method includes, for example, an aggregation step and a coalescence step. In the aggregation step, fine particles containing components constituting the toner base particles are aggregated in an aqueous medium to form aggregated particles. In the coalescence step, components contained in the aggregated particles are coalesced in the aqueous medium to form toner base particles.

[0076] Next, the pulverization method will be described. The pulverization method allows toner base particles to be prepared relatively easily and also enables reduction in production costs. When toner base particles are prepared by the pulverization method, the preparation process of the toner base particles includes, for example, a melt-kneading step and a pulverization step. The preparation process of the toner base particles may further include a mixing step before the melt-kneading step. Furthermore, the preparation process of the toner base particles may further include at least one of a fine pulverization step and a classification step after the pulverization step.

[0077] In the mixing step, a binder resin and an internal additive, which is added as needed, are mixed to obtain a mixture. In the melting and kneading step, the toner materials are melted and kneaded to obtain a molten and kneaded product. The mixture obtained in the mixing step, for example, is used as the toner material. In the pulverizing step, the obtained molten and kneaded product is cooled to, for example, room temperature (25°C) and then pulverized to obtain a pulverized product. If it is necessary to reduce the diameter of the pulverized product obtained in the pulverizing step, a step of further pulverizing the pulverized product (fine pulverizing step) may be performed. Furthermore, if the particle size of the pulverized product is to be uniform, a step of classifying the obtained pulverized product (classifying step) may be performed. Through the above steps, toner base particles, which are the pulverized product, are obtained.

[0078] (External addition process) In the external addition step, toner particles are obtained by adhering external additives containing fluorine-containing particles and silica particles to the surfaces of toner base particles. The method for adhering the external additives to the surfaces of toner base particles is not particularly limited, but examples thereof include a method in which the toner base particles and the external additives are stirred with a mixer or the like.

[0079] When the external additive is attached by stirring, the toner base particles and the external additive particles do not chemically react with each other and are fixed physically, not chemically. The degree of fixation between the toner base particles and the external additive particles can be adjusted by the stirring conditions (more specifically, the stirring time, the stirring rotation speed, etc.), the particle diameter of the external additive particles, the shape of the external additive particles, the surface condition of the external additive particles, etc. Therefore, by changing the stirring conditions, the development section durability silica content Si 1000D / Initial silica content Si0 and development zone durability fluorine content F 1000D The initial fluorine content F0 can be adjusted appropriately.

[0080] For example, the longer the stirring time for the toner base particles and silica particles, the more the silica particles are fixed to the surface of the toner base particles, and the less silica particles are detached from the toner base particles in the developing section. As a result, the development section durability silica content Si 1000D The silica content Si 1000DThe initial silica content Si0 also tends to decrease. In addition, the longer the stirring time for the toner base particles and fluorine-containing particles, the more the fluorine-containing particles are fixed to the surface of the toner base particles, and the amount of fluorine-containing particles detached from the toner base particles in the developing section decreases. As a result, the development section durability fluorine content F 1000D The fluorine content in the developing area is decreased, and 1000D / The initial fluorine content F0 also tends to decrease.

[0081] The fluorine-containing particles and silica particles may be added to the toner base particles simultaneously and stirred. Alternatively, one of the fluorine-containing particles and silica particles may be added to the toner base particles and stirred, and then the other may be added and further stirred. By adding the fluorine-containing particles and the silica particles at different times, the degree of fixation of the silica particles to the toner base particles and the degree of fixation of the fluorine-containing particles to the toner base particles can be adjusted independently.

[0082] [Second embodiment: image forming apparatus] The second embodiment of the present invention relates to an image forming apparatus. Hereinafter, an image forming apparatus 1, which is one example of the image forming apparatus of the present invention, will be described with reference to FIGS. 1 to 3 again. Note that the same reference symbols in the drawings represent the same or corresponding parts. Dimensional relationships such as length, width, thickness, and depth have been changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

[0083] As shown in FIG. 1, the image forming apparatus 1 includes a paper feed section 10, a conveyance section 11, an image forming section 12, a fixing section 13, a discharge section 14, and a control section 15.

[0084] The paper feed unit 10 includes a paper feed cassette 30 and a paper feed roller group 31. The paper feed cassette 30 can accommodate multiple recording media P. The paper feed roller group 31 feeds the recording media P accommodated in the paper feed cassette 30 one by one to the conveyance unit 11. The recording media P are made of, for example, paper or synthetic resin.

[0085] The conveying section 11 extends from the paper feeding section 10 to the discharge section 14. The conveying section 11 conveys the recording medium P from the paper feeding section 10 to the discharge section 14, passing through the image forming section 12 and the fixing section 13.

[0086] The image forming unit 12 includes an exposure unit 20, a charging unit 21, a developing unit 22, an image carrier 23, a cleaning unit 24, and a transfer unit 25. The charging unit 21, the developing unit 22, the transfer unit 25, and the cleaning unit 24 are arranged along the circumferential surface of the image carrier 23 in the order listed from the upstream side in the rotation direction R of the image carrier 23 (clockwise direction in FIG. 1).

[0087] The charging unit 21 uniformly charges the image carrier 23 to a preset polarity.

[0088] The exposure unit 20 irradiates (exposes) light onto the surface 23a of the charged image carrier 23. The exposure unit 20 exposes the surface 23a of the image carrier 23 based on image data input to the image forming apparatus 1. As a result, an electrostatic latent image is formed on the surface 23a of the image carrier 23.

[0089] The developing unit 22 contains toner T. The developing unit 22 supplies the toner T to the electrostatic latent image formed on the surface 23a of the image carrier 23, and develops the electrostatic latent image into a toner image. Details of the developing unit 22 will be described later.

[0090] Toner T is the toner described in the first embodiment. Therefore, for the same reasons as those described in the first embodiment, the image forming apparatus 1 equipped with toner T can form images with high image density and little thin layer streaks and fog. In the second embodiment, predetermined printing is performed using the image forming apparatus 1 of the second embodiment.

[0091] The image carrier 23 carries a toner image on its surface 23a. The image carrier 23 is, for example, a photosensitive drum.

[0092] The transfer unit 25 is disposed opposite the image carrier 23 and transfers the toner image on the image carrier 23 onto the recording medium P.

[0093] The cleaning unit 24 collects the toner T remaining on the surface 23a of the image carrier 23 after transfer from the surface 23a of the image carrier 23. The cleaning unit 24 will be described in detail later.

[0094] The fixing unit 13 includes a heating unit 40 and a pressure unit 41. The heating unit 40 and the pressure unit 41 are arranged opposite each other. The pressure unit 41 presses the heating unit 40 to form a fixing nip. The recording medium P onto which the toner image has been transferred passes through the fixing nip and is heated and pressurized. As a result, the toner T is fixed to the recording medium P. The recording medium P is transported from the fixing unit 13 to the discharge unit 14 by the transport unit 11.

[0095] The discharge section 14 includes a discharge roller pair 60 and a discharge tray 61. The discharge roller pair 60 discharges the recording medium P onto the discharge tray 61.

[0096] The control unit 15 controls the operation of each unit included in the image forming apparatus 1. The control unit 15 is, for example, a processor such as a CPU (Central Processing Unit). The control unit 15 comprehensively controls the operation of the image forming apparatus 1 to realize various functions.

[0097] Next, the details of the developing unit 22 will be described with reference to Fig. 2. As already mentioned, the developing unit 22 includes a storage frame 210, a supply roller 220, a developing roller 230, and a regulating blade 240. The lengths of the supply roller 220 and the developing roller 230 in the axial direction (the direction perpendicular to the paper surface of Fig. 2) are approximately the same as the length of the image carrier 23.

[0098] The storage frame 210 stores toner T therein. The storage frame 210 includes a supply roller 220, a developing roller 230, and a regulating blade 240 therein. The storage frame 210 has an opening 211, which is disposed opposite the image carrier 23. The opening 211 exposes a portion of the developing roller 230 to the outside of the storage frame 210.

[0099] Supply roller 220 is supported so as to be rotatable in the direction of the arrow in FIG. 2 (counterclockwise). Supply roller 220 carries toner T stored inside storage frame 210 on its surface (circumferential surface). A nip N1 is provided between development roller 230 and supply roller 220. In nip N1, supply roller 220 supplies toner T carried on its surface to development roller 230. In addition, in nip N1, toner T on supply roller 220 comes into contact with development roller 230, thereby causing frictional charging of toner T.

[0100] The developing roller 230 is supported so as to be rotatable in the direction of the arrow in FIG. 2 (counterclockwise). The developing roller 230 is disposed opposite the supply roller 220. The developing roller 230 is also disposed opposite the image carrier 23 through the opening 211 of the storage frame 210. The developing roller 230 carries the toner T supplied from the supply roller 220 on its surface (circumferential surface) 230a. More specifically, the toner T is carried on the surface 230a of the developing roller 230 due to the image force acting between the developing roller 230 and the toner T.

[0101] The developing roller 230 includes a conductive support 231, an elastic layer 232, and a coating layer 233. The elastic layer 232 is provided on the conductive support 231 (specifically, on the outer peripheral surface of the conductive support 231). The elastic layer 232 is made of, for example, silicone rubber. The coating layer 233 is provided on the elastic layer 232 (specifically, on the outer peripheral surface of the elastic layer 232). The coating layer is made of, for example, urethane.

[0102] The regulating blade 240 is plate-shaped. One end 241 of the regulating blade 240 is fixed to the containing frame 210, and the other end 242 is a free end. The regulating blade 240 is bent toward the opposite side to the developing roller 230 near the outer edge of the other end 242 (free end). The regulating blade 240 is made of, for example, stainless steel (SUS).

[0103] The regulating blade 240 is flexible and deformable so that the other end 242 approaches the developing roller 230. The developing roller 230 has one or more magnet portions (not shown) therein. The regulating blade 240 is magnetic. The magnetic force generated by the magnet portion of the developing roller 230 urges the other end 242 of the magnetic regulating blade 240 toward the developing roller 230. In this manner, a nip N2 is formed between the regulating blade 240 and the surface 230a of the developing roller 230. In the nip N2, the regulating blade 240 contacts (specifically, makes surface contact with) the toner layer formed on the surface 230a of the developing roller 230 with a predetermined pressure, thereby regulating the thickness of the toner layer. In order to regulate the thickness of the toner layer within a desired range, the pressure (regulating pressure) of the regulating blade 240 against the surface 230a of the developing roller 230 is preferably 15 N / m or more and 40 N / m or less. Furthermore, at the nip N2, the toner T on the developing roller 230 comes into contact with the regulating blade 240, so that the toner T is further triboelectrically charged.

[0104] When a development bias is applied to the development roller 230, the toner T contained in the toner layer is supplied from the development roller 230 to the electrostatic latent image formed on the surface 23a of the image carrier 23 through the opening 211. The details of the development unit 22 have been described above with reference to FIG.

[0105] Next, the cleaning unit 24 will be described in detail with reference to Fig. 3. As already described, the cleaning unit 24 includes a cleaning housing 50 and a cleaning member 51.

[0106] The cleaning member 51 is attached inside the cleaning housing 50. The cleaning member 51 is in the form of a plate extending in the direction of the rotation axis of the image carrier 23. The cleaning member 51 is, for example, a cleaning blade. The cleaning member 51 is made of, for example, rubber (more specifically, urethane rubber).

[0107] The cleaning member 51 is in pressure contact with the surface 23a of the image carrier 23 downstream of the transfer unit 25 in the rotation direction R of the image carrier 23. The cleaning member 51 is also in pressure contact with the surface 23a of the image carrier 23 from above the rotation axis of the image carrier 23. A direction D from the base end 51b of the cleaning member 51 toward the tip end 51a is a direction from above to below the rotation axis of the image carrier 23, and the tip end 51a is in contact with the surface 23a of the image carrier 23 above the rotation axis of the image carrier 23. The direction D from the base end 51b of the cleaning member 51 toward the tip end 51a is opposite to the rotation direction R of the image carrier 23 at a contact point CP between the tip end 51a of the cleaning member 51 and the surface 23a of the image carrier 23. That is, the tip 51a of the cleaning member 51 faces in a so-called counter direction to the rotation direction R of the image carrier 23. With this configuration, the cleaning member 51 can efficiently remove the toner T remaining on the surface 23a of the image carrier 23 after transfer. In order to efficiently remove the toner T, the linear pressure of the cleaning member 51 against the image carrier 23 is preferably 10 N / m or more and 30 N / m or less.

[0108] The cleaning housing 50 has a depth in the direction of the rotation axis of the image carrier 23. The cleaning housing 50 collects therein the toner T removed by the cleaning member 51. The cleaning unit 24 has been described in detail above with reference to FIG.

[0109] As described above, the image forming apparatus 1 shown in Fig. 1 has been described as an example of the image forming apparatus of the second embodiment. However, the image forming apparatus of the second embodiment is not limited to the image forming apparatus 1 described above, and can be modified in the following ways, for example.

[0110] For example, in the second embodiment described above, the image forming apparatus 1 is an apparatus that records an image using a single color toner, but is not limited to this. The image forming apparatus 1 may also be an apparatus that records a color image using multiple color toners.

[0111] Furthermore, in the second embodiment described above, the cleaning unit 24 includes the cleaning member 51, but this is not limiting. The cleaning unit 24 may further include a rubbing roller in addition to the cleaning member 51. Alternatively, the cleaning unit 24 may include a rubbing roller without including the cleaning member 51. The rubbing roller collects toner T from the surface 23a of the image carrier 23, and polishes the surface 23a of the image carrier 23 with the toner adhering to the surface of the rubbing roller.

[0112] In the second embodiment described above, the direction D from the base end 51b of the cleaning member 51 to the tip end 51a is a direction from above to below the rotation axis of the image carrier 23, and the tip end 51a is in contact with the surface 23a of the image carrier 23 above the rotation axis of the image carrier 23, but this is not limited to this. The direction D from the base end 51b of the cleaning member 51 to the tip end 51a may be a direction from below to above the rotation axis of the image carrier 23, and the tip end 51a may be in contact with the surface 23a of the image carrier 23 below the rotation axis of the image carrier 23. When counter-abutting in this configuration, the rotation direction of the image carrier 23 is opposite to the above-mentioned rotation direction R (counterclockwise in FIG. 1 ). [Example]

[0113] Examples of the present invention will be described below, but the present invention is not limited to the scope of the examples. First, methods for measuring physical property values ​​will be described.

[0114] [Number average primary particle size] The number-average primary particle diameter of the external additive particles was determined from particle projection images taken using a scanning electron microscope ("JSM-7600F" manufactured by JEOL Ltd.) Specifically, the external additive particles were observed using the scanning electron microscope, and the number-average primary particle diameter was determined as the number-average circle-equivalent diameter (Heywood diameter: diameter of a circle having the same area as the projected area of ​​a primary particle) of 100 external additive particles.

[0115] [Silica particles] Commercially available silica particles used as external additives are listed below. Silica particles (TG7120): Hydrophobic silica particles ("TG7120" manufactured by Cabot Specialty Chemicals, Inc., number-average primary particle diameter 20 nm) Silica particles (REA200): Hydrophobic silica particles (Nippon Aerosil Co., Ltd. "REA200", number average primary particle diameter 12 nm) Silica particles (NA50H): Hydrophobic silica particles (Nippon Aerosil Co., Ltd. "NA50H", number average primary particle diameter 40 nm) Silica particles (H3050VP): Hydrophobic silica particles (Wacker "H3050VP", number average primary particle diameter 8 nm) Silica particles (H05TA): Hydrophobic silica particles (Wacker "H05TA", number-average primary particle diameter 50 nm)

[0116] [Fluorine-containing particles] Fluorine-containing particles to be used as external additives were prepared by the following method. Details of the fluorine-containing particles are shown in the following Table 1. The "particle size" used in Table 1 indicates the number-average primary particle size.

[0117] [Table 1]

[0118] <Preparation of Fluorine-Containing Particles (FA)> An autoclave equipped with a stainless steel anchor-type stirring blade and a temperature-control jacket was used as the reaction vessel. 3580 mL of deionized water, 3.58 g of ammonium perfluorooctanoate, and 94.1 g of paraffin wax (Nippon Seikoh Co., Ltd., "Paraffin Wax-130") were charged to the reaction vessel. After purging the atmosphere with nitrogen gas and tetrafluoroethylene (TFE), TFE was further pressure-injected into the reaction vessel. The contents of the reaction vessel were stirred at a stirring speed of 250 rpm (hereinafter referred to as the stirring speed X), while the reaction vessel was heated to a temperature of 80°C and maintained at this temperature. While pressure-injecting an aqueous solution of ammonium persulfate (concentration: 0.067% by mass) and an aqueous solution of disuccinic acid peroxide (concentration: 1.61% by mass), TFE was continuously supplied to maintain a constant pressure (0.78 MPa) inside the reaction vessel. The polymerization reaction was carried out for 50 minutes (hereinafter referred to as the polymerization time Y). During the polymerization reaction, the injected amounts of ammonium persulfate aqueous solution, disuccinic acid peroxide aqueous solution, and TFE were 20 mL, 20 mL, and 1735 g, respectively. After the polymerization time Y, the supply of TFE and stirring of the contents of the reaction vessel were stopped, and the polymerization reaction was terminated. 100 mL of ammonium hydroperfluorononanoate aqueous solution (concentration: 10% by mass) was added to the latex-like reaction product obtained by the polymerization reaction. Next, warm water was added to the reaction product and the temperature was adjusted to 50°C. Next, 10 mL of nitric acid (concentration: 60% by mass) was added to the reaction product, and the reaction product was stirred at a stirring speed of 250 rpm. As a result, fluorine-containing particles (FA) began to coagulate from the reaction product. Next, the reaction product was stirred for 1 hour to thoroughly separate the fluorine-containing particles (FA) from the solvent. Next, the solvent was removed from the fluorine-containing particles (FA), and the fluorine-containing particles (FA) were dried to obtain fluorine-containing particles (FA) having the number-average primary particle diameter listed in Table 1.

[0119] <Preparation of fluorine-containing particles (FB) to (FE)> Fluorine-containing particles (FB) to (FE) were prepared in the same manner as in the preparation of fluorine-containing particles (FA), except that the stirring speed X and polymerization time Y were changed to the values ​​shown in Table 1.

[0120] [toner] The toners used in the examples and comparative examples were prepared by the following method, and the details of the toners are shown in Table 2 below.

[0121] [Table 2]

[0122] <Preparation of Toner (T-A1)> (Preparation of Polyester Resin) A polyester resin used as a binder resin for toner was prepared using the following method. 1.0 mol of polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane, 4.5 mol of terephthalic acid, 0.5 mol of trimellitic anhydride, and 4 g of dibutyltin oxide were placed in a reaction vessel. The contents of the reaction vessel were reacted at 230°C for 8 hours under a nitrogen atmosphere. Next, unreacted raw materials in the reaction vessel were distilled off under reduced pressure at 8.3 kPa. The resulting reaction product was washed and then dried. This resulted in a polyester resin with a softening point of 120°C.

[0123] (Preparation of Toner Base Particles) 100 parts by weight of the above-mentioned polyester resin as a binder resin, 5 parts by weight of carbon black ("REGAL® 330R" manufactured by Cabot Specialty Chemicals) as a colorant, 10 parts by weight of carnauba wax ("Carnauba No. 1" manufactured by Kato Yoko Co., Ltd.) as a release agent, and 3 parts by weight of a quaternary ammonium salt compound ("FCA210PS" manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent were mixed using an FM mixer ("FM20B" manufactured by Nippon Coke & Engineering Co., Ltd.). The resulting mixture was melted and kneaded at 150°C using a twin-screw extruder ("TEM45" manufactured by Toshiba Machine Co., Ltd.). The resulting kneaded mixture was cooled. The cooled kneaded mixture was coarsely pulverized using an impact screen-type fine pulverizer ("Feathermill® FM-2S 350 x 600" manufactured by Hosokawa Micron Corporation). The obtained coarsely pulverized material was finely pulverized using a supersonic jet pulverizer ("Jet Mill IDS-2" manufactured by Nippon Pneumatic Mfg. Co., Ltd.). The obtained finely pulverized material was classified using a classifier ("Elbow Jet EJ-LABO" manufactured by Nittetsu Mining Co., Ltd.). This resulted in the production of toner base particles. The volume median diameter (D 50 ) was 8 μm.

[0124] (external attachment) 100.0 parts by mass of toner base particles, silica particles, and fluorine-containing particles were placed in a container. The type and amount of silica particles and the type and amount of fluorine-containing particles placed were as shown in Table 2. The contents of the container were mixed for 5 minutes at a rotation speed of 3500 rpm using an FM mixer ("FM-10B" manufactured by Nippon Coke & Engineering Co., Ltd.). This allowed the external additive to adhere to the surface of the toner base particles. As a result, toner (T-A1) was obtained.

[0125] <Preparation of Toners (T-A2) to (T-A3) and (T-B1) to (T-B4)> Toners (T-A2) to (T-A3) and (T-B1) to (T-B4) were prepared in the same manner as in the preparation of toner (T-A1), except that the type and amount of silica particles and the type and amount of fluorine-containing particles added in the external addition were as shown in Table 2.

[0126] [Prescribed printing] A specified print was performed for each toner using the following method. The test machine used for the specified print was a modified monochrome printer (Kyocera Document Solutions Inc.'s "PA2000") that had been modified to include a cleaning unit. This test machine was equipped with a toner container, an image carrier, a developing unit equipped with a regulating blade, and a cleaning unit equipped with a cleaning blade. The toner to be measured (either toners (T-A1) to (T-A3) or (T-B1) to (T-B4)) was filled into the toner container of the test machine. Using the test machine, a standard test page image specified in ISO 19752 was printed on 1,000 sheets of recording medium (A4-size plain paper) under the following printing conditions.

[0127] <Printing conditions> Developing roller material: urethane coated silicone rubber Regulating blade material: SUS - Regulating blade pressure: 40N / m Cleaning blade material: urethane rubber Cleaning blade linear pressure: 20N / m Cleaning blade contact direction: Counter-contact Printing environment: Temperature 23°C and relative humidity 50%RH Printing mode: Intermittent printing, repeating two prints and then pausing for 400 seconds Printing speed: 20 pages / minute when feeding the recording medium in the length direction

[0128] [measurement] <Measurement of initial silica content Si0 and initial fluorine content F0> The toner before the above-mentioned predetermined printing was performed (i.e., the toner before being filled into the toner container of the test machine) was used as the measurement object. The measurement object was subjected to the following fluorescent X-ray analysis to determine the silica particle content in the toner particles and the fluorine-containing particle content in the toner particles. The silica particle content in the toner particles was defined as the initial silica content Si0. The fluorine-containing particle content in the toner particles was defined as the initial fluorine content F0. The initial silica content Si0 and the initial fluorine content F0 are shown in Table 3 below.

[0129] <X-ray fluorescence analysis> A 1.5 g sample was pressure-molded at a pressure of 20 MPa for 3 seconds to produce a cylindrical pellet with a diameter of 30 mm. X-ray fluorescence analysis was performed on the resulting pellet under the following conditions to obtain a fluorescent X-ray spectrum (horizontal axis: energy, vertical axis: intensity (number of photons)) containing peaks attributable to the measured elements (Si and F). Using a previously prepared calibration curve, the X-ray intensity of the peak attributable to the measured element Si in the obtained fluorescent X-ray spectrum was converted to the silica particle content (unit: mass%) of the toner particles. Furthermore, using a previously prepared calibration curve, the X-ray intensity of the peak attributable to the measured element F in the fluorescent X-ray spectrum was converted to the fluorine-containing particle content (unit: mass%) of the toner particles. The calibration curves were prepared using samples whose silica particle content and fluorine-containing particle content in the toner particles were known.

[0130] (X-ray fluorescence analysis conditions) Analytical equipment: Scanning X-ray fluorescence analyzer (Rigaku Corporation "ZSX") X-ray tube (X-ray source): Rh (rhodium) Excitation conditions: Tube voltage 50 kV, tube current 50 mA Measurement area (X-ray irradiation range): 30 mm diameter ·Measurement elements: Si, F

[0131] <Developing section durability silica content Si 1000D and development zone durability fluorine content F 1000D Measurement of After the above-mentioned predetermined printing was carried out, the toner was taken out from the developing unit of the test machine and used as the measurement object. The measurement object was subjected to the above-mentioned X-ray fluorescence analysis to determine the silica particle content in the toner particles and the fluorine-containing particle content in the toner particles. The silica particle content in the toner particles was determined as the development unit durability silica content Si 1000D The content of fluorine-containing particles in the toner particles was defined as the development section durability fluorine content F 1000D Durable silica content in the developing section Si 1000D and development zone durability fluorine content F 1000D The ratios are shown in Table 3. 1000D / Si0 = Durable silica content in the developing section Si 1000D / Initial silica content Si0 / Ratio (development section durability silica content Si 1000D The ratio F / initial silica content (SiO) is shown in Table 3. 1000D / F0 = Durable fluorine content in the developing area F 1000D Ratio calculated from "initial fluorine content F0" (development area durability fluorine content F 1000D / initial fluorine content F0) is shown in Table 3.

[0132] <Cleaning section durability silica content Si 1000C and cleaning part durability fluorine content F 1000C Measurement of After the above-mentioned predetermined printing was carried out, the toner was taken out from the cleaning unit of the test machine and used as the measurement object. The measurement object was subjected to the above-mentioned X-ray fluorescence analysis to determine the content of silica particles in the toner particles and the content of fluorine-containing particles in the toner particles. The content of silica particles in the toner particles was determined as the cleaning unit durability silica content Si 1000C The content of fluorine-containing particles in the toner particles was defined as the cleaning section durability fluorine content F 1000C Cleaning section durability silica content Si 1000C and cleaning part durability fluorine content F 1000C are shown in Table 4 below. For ease of understanding, the initial silica content Si0 and the initial fluorine content F0 shown in Table 3 are also shown in Table 4.1000C / Si0 = cleaning section durability silica content Si 1000C / Initial silica content Si0 / Ratio calculated from (Cleaning section durable silica content Si 1000C The ratio F / initial silica content (SiO) is shown in Table 4. 1000C / F0 = Durable fluorine content of cleaning part F 1000C Ratio calculated from "initial fluorine content F0" (cleaning part durable fluorine content F 1000C / initial fluorine content F0) is shown in Table 4.

[0133] [Table 3]

[0134] [Table 4]

[0135] [evaluation] Images printed using each of the toners (T-A1) to (T-A3) and (T-B1) to (T-B4) were evaluated for thin layer streaks, image density, fogging, and white spots using the following methods. The evaluation results are shown in Table 5 below.

[0136] <Print> After printing 1000 recording media (1st to 1000th sheets) using the above-mentioned predetermined printing method, printing was then performed on another 500 recording media (1001st to 1500th sheets) using the same method as the predetermined printing method.

[0137] <Thin layer streaks> The image printed on the 1500th sheet was visually observed to determine whether thin layer streaks were present. The thin layer streaks were evaluated according to the following criteria.

[0138] (Standard for thin layer streaks) A (good): No thin layer streaks were observed. B (bad): Thin streaks were observed.

[0139] <Image density> The reflection density (ID) of the printed image on the 1500th sheet was measured using a white light meter (TC-6DX manufactured by Tokyo Denshoku Co., Ltd.) The image density was judged according to the following criteria.

[0140] (Image density standard) A (Good): ID is 1.20 or higher. B (bad): ID is less than 1.20.

[0141] <Focus> The reflection density A of the non-printed area (white area) of the image printed on the 1500th sheet was measured using a white light meter ("TC-6DX" manufactured by Tokyo Denshoku Co., Ltd.). In addition, the reflection density B of the unprinted recording medium was measured using a white light meter ("TC-6DX" manufactured by Tokyo Denshoku Co., Ltd.). The fog density (FD) was calculated from the formula "Fog density = Reflection density A - Reflection density B". Fog was evaluated according to the following criteria.

[0142] (Fog standard) A (good): FD is 0.010 or less. B (poor): FD is greater than 0.010.

[0143] <Whiteout> The image printed on the 1500th sheet was visually observed to determine whether or not there were any white spots. The white spots were determined according to the following criteria.

[0144] (White standard) A (good): No white spots were observed. B (bad): White spots were observed.

[0145] In addition, if image defects (thin layer streaks, poor image density, fogging, or white spots) were found in images printed before the 1,500th sheet, details of the image defects were added to the remarks column of Table 5.

[0146] [Table 5]

[0147] The toners (T-A1) to (T-A3) each contained toner particles, and the toner particles had toner base particles and external additives attached to the surfaces of the toner base particles. The external additives contained silica particles and fluorine-containing particles. The toners were prepared by the formula (1) "0.5≦Si 1000D The toner satisfied the formula (2) "1.0≦F 1000D The toners (T-A1) to (T-A3) were evaluated as being good in terms of thin layer streaks, image density, and fogging.

[0148] On the other hand, the toner (T-B1) has a ratio (development section durability fluorine content F 1000D / initial fluorine content F0) is less than 1.0, and the formula (2) "1.0≦F 1000D The toner (T-B1) was evaluated as poor in terms of thin layer streaks and image density.

[0149] Toner (T-B2) is a ratio (development section durability fluorine content F 1000D / initial fluorine content F0) is greater than 1.5, and the formula (2) "1.0≦F 1000D The evaluation of the fogging of the toner (T-B2) was poor.

[0150] The toner (T-B3) has a silica content of 100% (Si 1000D / initial silica content Si0) is less than 0.5, and the formula (1) "0.5≦Si 1000D The toner (T-B3) was evaluated as poor in terms of thin layer streaks and image density.

[0151] The toner (T-B4) has a ratio (development section durability silica content Si 1000D / initial silica content Si0) is greater than 1.0, and the formula (1) "0.5≦Si 1000D The evaluation of thin layer streaks for the toner (T-B4) was poor.

[0152] From the above, it is judged that the toners of the present invention, including the toners (T-A1) to (T-A3), can form images with high image density and little thin layer streaks and fog.

[0153] Furthermore, the toners (T-A1) to (T-A3) each satisfy the formula (3) "0.7≦Si 1000C / Si0≦0.9”, and formula (4) “2.0≦F 1000C The toners (T-A1) to (T-A3), which satisfy the formulas (3) and (4) in addition to the formulas (1) and (2), were evaluated favorably for thin layer streaks, image density, and fogging, as well as for white spots. [Industrial Applicability]

[0154] The image forming apparatus of the present invention can be used to form images as, for example, a multifunction machine or a printer. [Explanation of symbols]

[0155] 1: Image forming device 22: Development unit 23: Image carrier 24: Cleaning section P: Recording medium T: Toner

Claims

1. A non-magnetic monocomponent toner comprising toner particles, The toner particles include toner base particles and an external additive attached to the surface of the toner base particles, the external additive includes silica particles and fluorine-containing particles, In a predetermined printing operation in which a standard test page image defined in ISO 19752 is printed on 1,000 sheets of recording medium, The content Si of the silica particles in the toner particles before the predetermined printing 0 and the content Si of the silica particles in the toner particles in the developing unit after the predetermined printing. 1000D and satisfy the following formula (1): The content F of the fluorine-containing particles in the toner particles before the predetermined printing 0 and the content F of the fluorine-containing particles in the toner particles in the developing unit after the predetermined printing. 1000D and a non-magnetic one-component toner, which satisfies the following formula (2). 0.5≦Yes 1000D / Yes 0 ≦1.0 ・・・(1) 1.0≦F 1000D / F 0 ≦1.5 ・・・(2)

2. The content Si of the silica particles in the toner particles before the predetermined printing 0 and the content Si of the silica particles in the toner particles in the cleaning unit after the predetermined printing. 1000C and satisfy the following formula (3): The content F of the fluorine-containing particles in the toner particles before the predetermined printing 0 and the content F of the fluorine-containing particles in the toner particles in the cleaning unit after the predetermined printing. 1000C 2. The non-magnetic one-component toner according to claim 1, wherein the following formula (4) is satisfied: 0.7≦Yes 1000C / Yes 0 ≦0.9 ・・・(3) 2.0≦F 1000C / F 0 ≦2.5 ・・・(4)

3. 3. The non-magnetic single-component toner according to claim 1, wherein the content of the silica particles relative to 100.0 parts by mass of the toner base particles before the predetermined printing is 1.5 parts by mass or more and 2.5 parts by mass or less.

4. 3. The non-magnetic single-component toner according to claim 1, wherein the content of the fluorine-containing particles relative to 100.0 parts by mass of the toner base particles before the predetermined printing is 0.3 parts by mass or more and 1.0 part by mass or less.

5. 3. The non-magnetic single-component toner according to claim 1, wherein a ratio WSi / WF of a content WF of the fluorine-containing particles relative to 100.0 parts by mass of the toner base particles before the predetermined printing to a content WSi of the silica particles relative to 100.0 parts by mass of the toner base particles before the predetermined printing is 2.5 or more and 5.0 or less.

6. the number average primary particle diameter of the silica particles is 12 nm or more and 40 nm or less; 3. The non-magnetic single-component toner according to claim 1, wherein the number average primary particle diameter of the fluorine-containing particles is 100 nm or more and 300 nm or less.

7. 3. The non-magnetic single-component toner according to claim 1, wherein the fluorine-containing particles are fluororesin particles.

8. an image carrier; an image forming apparatus including a developing unit that supplies a non-magnetic one-component toner to an electrostatic latent image formed on the surface of the image carrier, The non-magnetic single-component toner includes toner particles, The toner particles include toner base particles and an external additive attached to the surface of the toner base particles, the external additive includes silica particles and fluorine-containing particles, In a predetermined printing operation in which a standard test page image defined in ISO 19752 is printed on 1,000 sheets of recording medium, The content Si of the silica particles in the toner particles before the predetermined printing 0 and the content Si of the silica particles in the toner particles in the developing unit after the predetermined printing. 1000D and satisfy the following formula (1): The content F of the fluorine-containing particles in the toner particles before the predetermined printing 0 and the content F of the fluorine-containing particles in the toner particles in the developing unit after the predetermined printing. 1000D and the image forming apparatus satisfies the following formula (2): 0.5≦Yes 1000D / Yes 0 ≦1.0 ・・・(1) 1.0≦F 1000D / F 0 ≦1.5 ・・・(2)

9. a cleaning unit that collects the non-magnetic single-component toner from the surface of the image carrier; The content Si of the silica particles in the toner particles before the predetermined printing 0 and the content Si of the silica particles in the toner particles in the cleaning unit after the predetermined printing. 1000C and satisfy the following formula (3): The content F of the fluorine-containing particles in the toner particles before the predetermined printing 0 and the content F of the fluorine-containing particles in the toner particles in the cleaning unit after the predetermined printing. 1000C 9. The image forming apparatus according to claim 8, wherein the following formula (4) is satisfied: 0.7≦Yes 1000C / Yes 0 ≦0.9 ・・・(3) 2.0≦F 1000C / F 0 ≦2.5 ・・・(4)

Images