Image forming device and toner cartridge

Abstract

The present invention provides an image forming apparatus and a toner cartridge. The image forming apparatus comprises: an image holder; a charging mechanism; an electrostatic image forming mechanism; a developing mechanism; a transfer mechanism; a fixing mechanism; a replenishing toner storage; a replenishing toner storage mounting portion; and a toner supply path connecting the replenishing toner storage mounting portion and the developing mechanism for replenishing the replenishing toner to the developing mechanism. The replenishing toner contains toner particles and silica particles, wherein the silica particles have a number average particle size of 110 nm to 130 nm, a large diameter side number particle size distribution index (upper GSDp) of less than 1.080, an average circularity of 0.94 to 0.98, and a proportion of particles having a circularity of 0.92 or greater of 80% by number.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus and a toner cartridge. Background Art

[0002] Japanese Patent Application Laid-Open No. 2004-139031 discloses a toner bottle having a spiral groove provided in a bottle body and discharging toner by rotation.

[0003] Japanese Patent Application Publication No. 2017-057094 discloses silica particles having a compression agglomeration degree of 60% to 95%, a particle compression ratio of 0.20 to 0.40, an average equivalent circle diameter of 40 nm to 200 nm, and a particle dispersion of 90% to 100%.

[0004] Japanese Patent Application Laid-Open No. 2013-053027 discloses silica particles having a volume average particle size of 80 nm to 300 nm, an average circularity of 0.92 to 0.935, and a geometric standard deviation of circularity of 1.02 to 1.15, and a toner containing the silica particles.

[0005] Japanese Patent Application Laid-Open No. 2008-174430 discloses hydrophobic spherical silica particles having a particle size in the range of 0.01 μm to 5 μm and a roundness in the range of 0.8 to 1.

[0006] Japanese Patent Application Laid-Open No. 2001-194824 discloses spherical hydrophobic silica particles having an average particle size of 0.01 μm to 5 μm. Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] The technical problem to be solved by the present invention is to provide an image forming device, which can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction of image density in a high-temperature and high-humidity environment, compared with a case where a replenishing toner containing silica particles with a number average particle size of not less than 110 nm and not more than 130 nm and a large-diameter side number particle size distribution index (upper side GSDp) of not less than 1.080 is stored in a replenishing toner storage device that discharges the replenishing toner by rotation.

[0009] Means for solving technical problems

[0010] According to a first aspect of the present invention, there is provided an image forming apparatus comprising: an image holder; a charging mechanism for charging a surface of the image holder; an electrostatic image forming mechanism for forming an electrostatic image on the charged surface of the image holder; a developing mechanism for storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder into a toner image using the electrostatic image developer; a transferring mechanism for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; a replenishing toner storage for storing replenishing toner for replenishing to the developing mechanism and discharging the replenishing toner by rotation; a replenishing toner storage mounting portion for mounting the replenishing toner storage and rotating the replenishing toner storage; and a toner replenishing path for connecting the replenishing toner storage mounting portion and the developing mechanism and for replenishing the replenishing toner to the developing mechanism.

[0011] The above-mentioned replenishing toner contains toner particles and silica particles, the number average particle size of the silica particles is greater than 110nm and less than 130nm, the number particle size distribution index on the large diameter side (upper side GSDp) is less than 1.080, the average roundness is greater than 0.94 and less than 0.98, and the proportion of particles with a roundness of greater than 0.92 is greater than 80%.

[0012] According to the second aspect of the present invention, the silica particles have a large-diameter number size distribution index (upper GSDp) of less than 1.075.

[0013] According to the third aspect of the present invention, the silica particles have a smaller diameter side number size distribution index (lower GSDp) of less than 1.080.

[0014] According to a fourth aspect of the present invention, the silica particles have an average circularity of 0.95 to 0.97.

[0015] According to the fifth aspect of the present invention, the proportion of the silica particles having a circularity of 0.92 or greater is 85% by number or greater.

[0016] According to a sixth aspect of the present invention, the replenishment toner further contains inorganic oxide particles having a number average particle size of 5 nm to 50 nm.

[0017] According to a seventh aspect of the present invention, the toner particles contain a styrene acrylic resin as a binder resin.

[0018] According to an eighth aspect of the present invention, the toner particles contain an amorphous polyester resin as a binder resin.

[0019] According to a ninth aspect of the present invention, the toner storage portion of the replenishing toner container is made of polyethylene terephthalate or polyolefin.

[0020] According to the tenth aspect of the present invention, the replenishing toner storage has a toner discharge port at one end surface in the longitudinal direction, and a convex portion spirally continuous toward the toner discharge port is provided on the inner side surface of the toner storage portion.

[0021] According to the eleventh aspect of the present invention, the average width of the projections is 2 mm to 10 mm, the average height is 2 mm to 10 mm, and the average spiral period is 20 mm to 100 mm.

[0022] According to the twelfth aspect of the present invention, the replenishing toner storage is mounted on the replenishing toner storage mounting portion with its major axis oriented horizontally.

[0023] The replenishing toner container mounting portion rotates the replenishing toner container in a horizontal direction.

[0024] According to a thirteenth aspect of the present invention, there is provided a toner cartridge that is loaded and unloaded in an image forming apparatus, the cartridge storing a replenishing toner containing toner particles and silica particles, the silica particles having a number average particle size of 110 nm to 130 nm, a large diameter side number size distribution index (upper GSDp) of less than 1.080, an average circularity of 0.94 to 0.98, and a proportion of particles having a circularity of 0.92 or greater of 80% by number or greater.

[0025] The toner cartridge discharges the replenishment toner by rotating.

[0026] Effects of the Invention

[0027] According to the above-mentioned schemes 1, 7, 8, 9, 10, 11 or 12, an image forming device is provided, which can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction of image density in a high-temperature and high-humidity environment, compared with the case where a replenishing toner containing silica particles with a number average particle size of not less than 110 nm and not more than 130 nm and a large-diameter side number particle size distribution index (upper side GSDp) of not less than 1.080 is stored in the replenishing toner storage.

[0028] According to the above-mentioned second scheme, an image forming device is provided, which can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction in image density in a high-temperature and high-humidity environment, compared with the case where the large-diameter side number particle size distribution index (upper side GSDp) of the silica particles is greater than 1.075.

[0029] According to the third embodiment, an image forming apparatus is provided that can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction in image density in a high-temperature and high-humidity environment, compared to a case where the small-diameter side number size distribution index (lower GSDp) of silica particles is 1.080 or greater.

[0030] According to the fourth aspect, an image forming apparatus is provided that can suppress the occurrence of blurring in a low-temperature, low-humidity environment and the reduction in image density in a high-temperature, high-humidity environment, compared to the case where the average circularity of silica particles is less than 0.95 or greater than 0.97.

[0031] According to the fifth embodiment, an image forming apparatus is provided that can suppress the occurrence of blurring in a low-temperature, low-humidity environment and the reduction in image density in a high-temperature, high-humidity environment, compared to a case where the proportion of silica particles having a roundness of 0.92 or greater is less than 85% by number.

[0032] According to the above-mentioned sixth scheme, an image forming device is provided, which can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction of image density in a high-temperature and high-humidity environment compared to a case where the device does not contain inorganic oxide particles having a number average particle size of 5 nm to 50 nm.

[0033] According to the above-mentioned scheme 13, a toner box is provided, which can suppress the occurrence of blurring in a low-temperature and low-humidity environment and the reduction of image density in a high-temperature and high-humidity environment, compared with the case of storing a replenishing toner containing silica particles with a number average particle size of not less than 110 nm and not more than 130 nm and a large-diameter side number particle size distribution index (upper side GSDp) of not less than 1.080. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment.

[0035] Figure 2 This is a schematic structural diagram showing an example of an image holding member, a developing mechanism, a toner supply path, a replenishing toner storage container mounting portion, and a replenishing toner storage container included in the image forming apparatus according to the present embodiment.

[0036] Figure 3 This is a schematic structural diagram showing an example of a toner cartridge according to this embodiment. DETAILED DESCRIPTION

[0037] The following describes embodiments of the present invention. These descriptions and examples are provided to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0038] In the present invention, the numerical range expressed using “to” indicates a range including the numerical values ​​described before and after “to” as the minimum value and the maximum value, respectively.

[0039] In the numerical range described in stages in the present invention, the upper limit or lower limit described in one numerical range can be replaced by the upper limit or lower limit of the numerical range in other stages described. In addition, in the numerical range described in the present invention, the upper limit or lower limit of the numerical range can be replaced by the value shown in the embodiments.

[0040] The term "step" in the present invention includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

[0041] While the embodiments of the present invention are described with reference to the drawings, the configuration of the embodiments is not limited to that shown in the drawings. In addition, the sizes of the components in the drawings are schematic, and the relative sizes of the components are not limited thereto.

[0042] Each component in the present invention may contain two or more corresponding substances. When referring to the amount of each component in the composition of the present invention, if there are two or more substances corresponding to each component in the composition, unless otherwise stated, the amount refers to the total amount of the two or more substances present in the composition.

[0043] The particles corresponding to each component in the present invention may include two or more types. When two or more types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for the mixture of the two or more types of particles present in the composition unless otherwise stated.

[0044] In the present invention, the term "(meth)acrylic acid" means that it may be either "acrylic acid" or "methacrylic acid".

[0045] <Image Forming Apparatus>

[0046] The image forming apparatus of this embodiment includes:

[0047] Image holding body;

[0048] A charging mechanism for charging the surface of the image holding body;

[0049] An electrostatic image forming mechanism for forming an electrostatic image on the surface of the charged image holding member;

[0050] a developing mechanism storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer;

[0051] a transfer mechanism for transferring the toner image formed on the surface of the image holding member to the surface of the recording medium;

[0052] a fixing mechanism for fixing the toner image transferred to the surface of the recording medium;

[0053] a replenishing toner storage for storing replenishing toner for supplying to the developing mechanism and discharging the replenishing toner by rotating;

[0054] a replenishing toner storage mounting portion for mounting the replenishing toner storage and rotating the replenishing toner storage; and

[0055] The toner supply passage connects the replenishment toner storage mounting portion and the developing mechanism, and supplies the replenishment toner to the developing mechanism.

[0056] Furthermore, in the image forming device of this embodiment, the replenishing toner contains toner particles and silica particles, the number average particle size of the silica particles is greater than 110 nm and less than 130 nm, the number particle size distribution index on the large diameter side (upper side GSDp) is less than 1.080, the average roundness is greater than 0.94 and less than 0.98, and the proportion of particles with a roundness of greater than 0.92 is greater than 80%.

[0057] The image forming apparatus of this embodiment can suppress the occurrence of blurring in a low-temperature, low-humidity environment (e.g., 10°C and 10% relative humidity) and a decrease in image density in a high-temperature, high-humidity environment (e.g., 30°C and 85% relative humidity). The mechanism for this is presumably as follows.

[0058] As a known replenishing toner storage container, there is a container that discharges toner by rotating (hereinafter also referred to as a "rotating toner bottle"). Rotating toner bottles are superior to replenishing toner storage containers equipped with a toner stirring mechanism, such as a propeller screw, in terms of container recyclability and reduced mechanical load on the toner. However, because rotating toner bottles lack a toner stirring mechanism, the fluidity of the toner itself significantly affects toner discharge efficiency. To ensure the stability of the toner replenishment amount and suppress image defects when using a rotating toner bottle, it is necessary to improve the environmental stability of the toner's fluidity. Therefore, in this embodiment, the replenishing toner is constructed as described below.

[0059] As an external additive to the toner, silica particles (referred to as "large-diameter silica particles" in this specification) with a number average particle size of 110 nm to 130 nm are used, which are expected to have a spacer effect (the effect of creating a moderate distance between toner particles). Large-diameter silica particles sometimes contain even larger silica particles (referred to as "coarse silica particles" in this specification), and the coarse silica particles have the effect of further improving the fluidity of the toner. Therefore, the toner containing coarse silica particles is easily discharged from the replenishing toner storage and has a tendency to be oversupplied to the developing mechanism. When the amount of toner in the developing mechanism is excessive, the charge in the developing mechanism is insufficient due to friction with the carrier, resulting in blurring ("blurring" refers to the phenomenon of an undesirable dot-shaped image appearing on the imaging surface of the recording medium). This phenomenon is significant in a low-temperature and low-humidity environment where the fluidity of the toner is higher.

[0060] Therefore, in this embodiment, the above phenomenon is suppressed by making the large diameter side number particle size distribution index (upper side GSDp) of the large diameter silica particles contained in the replenishing colorant less than 1.080, that is, by suppressing the content of coarse silica particles. As a result, the occurrence of blurring in a low temperature and low humidity environment can be suppressed.

[0061] In addition, when the average circularity of the large-diameter silica particles exceeds 0.98, the fluidity of the toner increases and the toner tends to be excessively supplied to the developing device. Therefore, setting the average circularity of the large-diameter silica particles to 0.98 or less can suppress the occurrence of fogging in a low-temperature and low-humidity environment.

[0062] When large-diameter silica particles are added to toner in the hope of creating a spacer effect, if the large-diameter silica particles have low roundness, the number of contact points between the large-diameter silica particles and the toner particles increases, leading to a tendency for toner particles to aggregate. Consequently, toner containing large-diameter silica particles with low roundness is prone to aggregation within the replenishing toner reservoir, resulting in insufficient toner supply to the developer and a tendency for image density to decrease. This phenomenon is particularly pronounced in high-temperature and high-humidity environments, where toner fluidity is further reduced.

[0063] Therefore, in this embodiment, the above phenomenon can be suppressed by making the average circularity of the large-diameter silica particles contained in the replenishing colorant greater than 0.94 and the proportion of large-diameter silica particles with a circularity of greater than 0.92 greater than 80% by number, thereby suppressing the reduction in image density in a high temperature and high humidity environment.

[0064] Next, the configuration of the image forming apparatus according to this embodiment will be described in detail.

[0065] The image forming device of this embodiment can be applied to the following well-known image forming devices: a device using a direct transfer method for directly transferring a toner image formed on the surface of an image holder to a recording medium; a device using an intermediate transfer method for transferring a toner image formed on the surface of an image holder to the surface of an intermediate transfer member for the first time, and transferring the toner image transferred to the surface of the intermediate transfer member to the surface of a recording medium for the second time; a device having a cleaning mechanism for cleaning the surface of an image holder after the toner image is transferred and before charging; a device having a static elimination mechanism for eliminating static by irradiating the surface of an image holder with static elimination light after the toner image is transferred and before charging; and the like.

[0066] When the image forming device of this embodiment is an intermediate transfer type device, the transfer mechanism used is, for example, a structure having the following components: an intermediate transfer body to which the toner image is transferred to a surface; a primary transfer mechanism that transfers the toner image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the first time; and a secondary transfer mechanism that transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0067] In the image forming apparatus of this embodiment, the portion including the developing mechanism may be a cartridge structure (process cartridge) that is detachably mounted in the image forming apparatus. As the process cartridge, for example, a process cartridge that stores an electrostatic image developer and includes a developing mechanism may be suitably used.

[0068] An image forming method is implemented using the image forming device of this embodiment, and the method has the following steps: a charging step of charging the surface of the image retaining body; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image retaining body; a developing step of developing the electrostatic image formed on the surface of the image retaining body into a toner image using an electrostatic image developer; a transfer step of transferring the toner image formed on the surface of the image retaining body to the surface of a recording medium; a fixing step of fixing the toner image transferred to the surface of the recording medium; and a toner replenishing step of replenishing the toner from the replenishing toner storage to the developing mechanism through a toner replenishing path connecting the replenishing toner storage mounting portion and the developing mechanism.

[0069] An example of the image forming apparatus according to the present embodiment is shown below, but the present invention is not limited thereto. In the following description, the main parts shown in the drawings are described, and the other parts are omitted.

[0070] Figure 1 2 is a diagram schematically showing the configuration of the image forming apparatus according to this embodiment.

[0071] Figure 1The image forming apparatus shown includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming mechanisms) that output images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes referred to as "units") 10Y, 10M, 10C, and 10K are arranged in parallel horizontally, spaced a predetermined distance apart from one another. These units 10Y, 10M, 10C, and 10K may be process cartridges that are attachable to and detachable from the image forming apparatus.

[0072] An intermediate transfer belt (an example of an intermediate transfer member) 20 is installed above each unit 10Y, 10M, 10C, and 10K, extending through each unit. The intermediate transfer belt 20 is wound around a drive roller 22 and a support roller 24, traveling from the first unit 10Y toward the fourth unit 10K. The support roller 24 is biased away from the drive roller 22 by a spring (not shown), thereby applying tension to the intermediate transfer belt 20 wound between the drive roller 22 and the support roller 24. An intermediate transfer member cleaning device 30 is provided on the image holder side of the intermediate transfer belt 20, facing the drive roller 22.

[0073] Figure 1 The image forming apparatus shown has a removable configuration of toner cartridges 8Y, 8M, 8C, and 8K, serving as an example of a replenishing toner storage unit. The developing devices 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are connected to the toner cartridges 8Y, 8M, 8C, and 8K, respectively, via replenishing toner storage mounting portions and toner replenishment paths (neither shown). Toner of each color is replenished from the toner cartridges 8Y, 8M, 8C, and 8K via the toner replenishment paths. When the toner stored in the toner cartridges is insufficient, the toner cartridges are replaced.

[0074] The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore the first unit 10Y disposed upstream in the traveling direction of the intermediate transfer belt and forming a yellow image will be described as a representative.

[0075] The first unit 10Y includes a photoreceptor 1Y, which functions as an image holder. Sequentially arranged around the photoreceptor 1Y are: a charging roller (an example of a charging mechanism) 2Y, which charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming mechanism) 3, which exposes the charged surface using laser light 3Y based on a color separation image signal to form an electrostatic image; a developing device (an example of a developing mechanism) 4Y, which supplies the charged toner to the electrostatic image to develop it; a primary transfer roller 5Y (an example of a primary transfer mechanism), which transfers the developed toner image to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning unit) 6Y, which removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer.

[0076] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, positioned opposite the photoreceptor 1Y. Each of the primary transfer rollers 5Y, 5M, 5C, and 5K in each unit is connected to a bias power supply (not shown) for applying a primary transfer bias. Each bias power supply is controlled by a control unit (not shown) to change the value of the transfer bias applied to each primary transfer roller.

[0077] Next, the operation of forming a yellow image in the first unit 10Y will be described.

[0078] First, before operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roller 2Y.

[0079] The photoreceptor 1Y has a conductivity (e.g., a volume resistivity of 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate (with a resistance of Ωcm or less). This photosensitive layer normally has a high electrical resistance (commonly seen in resins), but when irradiated with laser light, the resistivity of the portion exposed to the laser light changes. Therefore, based on yellow image data sent from a control unit (not shown), laser light 3Y is irradiated from exposure device 3 onto the charged surface of photoreceptor 1Y. This forms an electrostatic image of a yellow image pattern on the surface of photoreceptor 1Y.

[0080] The electrostatic image is an image formed on the surface of the photoreceptor 1Y by charging, which is a so-called negative latent image. The negative latent image is formed as follows: the resistivity of the irradiated portion of the photosensitive layer is reduced by using the laser beam 3Y, so that the charged charge on the surface of the photoreceptor 1Y flows; on the other hand, the charge of the portion not irradiated by the laser beam 3Y remains, thereby forming the negative latent image.

[0081] The electrostatic image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y moves. At the development position, the electrostatic image on the photoreceptor 1Y is developed into a toner image by the developing device 4Y and visualized.

[0082] The developing device 4Y stores an electrostatic image developer, for example, containing at least yellow toner and a carrier. The yellow toner is triboelectrically charged by agitation within the developing device 4Y, acquiring a charge of the same polarity (negative) as the charge on the photoreceptor 1Y and being retained on the developer roller (an example of a developer retainer). The yellow toner then passes through the developing device 4 on the surface of the photoreceptor 1Y, where it electrostatically adheres to the de-electrified latent image on the surface of the photoreceptor 1Y, developing the latent image with the yellow toner. The photoreceptor 1Y, bearing the yellow toner image, continues to operate at a predetermined speed, transferring the developed toner image on the photoreceptor 1Y to a predetermined primary transfer position.

[0083] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y. The electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y to the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner and is controlled by a control unit (not shown) in the first unit 10Y to, for example, +10 μA.

[0084] On the other hand, the toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0085] The primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K in and after the second unit 10M is also controlled in accordance with the first unit.

[0086] In this manner, the intermediate transfer belt 20 to which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, so that the toner images of the respective colors are multiply transferred in a superimposed manner.

[0087] After passing through the first through fourth units and having four-color toner images multiply transferred onto the intermediate transfer belt 20, the intermediate transfer belt 20 reaches the secondary transfer section. This section comprises the intermediate transfer belt 20, a backup roller 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roller (an example of a secondary transfer mechanism) 26 positioned on the image-holding side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of recording medium) P is fed by a feeding mechanism at a predetermined timing to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20. A secondary transfer bias is applied to the backup roller 24. The applied transfer bias has the same (-) polarity as the toner (-). Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image from the intermediate transfer belt 20 to the recording paper P. The secondary transfer bias is determined based on the resistance detected by a resistance detection mechanism (not shown) that detects the resistance of the secondary transfer section, and the voltage is controlled accordingly.

[0088] Thereafter, the recording paper P is fed into a pressure-contact portion (nip portion) of a pair of fixing rollers in a fixing device (an example of a fixing mechanism) 28 , whereby the toner image is fixed to the recording paper P to form a fixed image.

[0089] Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copy machines, printers, etc. Examples of the recording medium include OHP transparent film paper, in addition to the recording paper P.

[0090] To further improve the smoothness of the image surface after fixing, the surface of the recording paper P is preferably smooth. For example, coated paper obtained by coating the surface of plain paper with resin or the like, or art paper for printing, is suitable.

[0091] The recording paper P on which the color image has been fixed is fed to the discharge portion, completing a series of color image forming operations.

[0092] Figure 2 This is a schematic structural diagram showing an example of an image holding member, a developing mechanism, a toner supply path, a replenishing toner storage container mounting portion, and a replenishing toner storage container included in the image forming apparatus according to the present embodiment.

[0093] Figure 2 The illustrated configuration example includes a photoreceptor 102 as an example of an image holding member, a developing device 104 as an example of a developing mechanism, a toner supply passage 108 , a replenishing toner reservoir mounting portion 106 , and a replenishing toner reservoir 200 .

[0094] The developing device 104 is divided into two chambers, for example, by a partition. One chamber is provided with an outlet for the toner supply passage 108, and the other chamber is provided with a developing roller facing the photoreceptor 102. The two chambers are partially connected, and each chamber includes a stirring member for stirring and conveying the developer. The developer (not shown) within the developing device 104 is stirred and conveyed by the two stirring members and then supplied to the developing roller.

[0095] One end of the toner supply passage 108 is connected to the replenishing toner reservoir mounting portion 106, and the other end is connected to the developing device 104. An auger screw 110, an example of a toner transport member, is disposed within the toner supply passage 108. The rotation of the auger screw 110 causes toner to flow through the toner supply passage 108. Alternatively, a toner transport member such as an auger screw may not be disposed within the toner supply passage 108. In this case, the toner flows through the toner supply passage 108 by, for example, free fall.

[0096] The replenishing toner container mounting portion 106 is used to detachably mount the replenishing toner container 200 on the image forming apparatus. The replenishing toner container mounting portion 106 includes a toner receiving port that communicates with the toner discharge port of the replenishing toner container 200, and a rotating member (e.g., a gear) that rotates the replenishing toner container 200.

[0097] The replenishing toner storage 200 stores a specific toner described later as replenishing toner for replenishing the developing device 104. The replenishing toner storage 200 includes a bottle body 202 (an example of a toner storage unit), a cap 204, a gear 206, and a shutter 208 for opening and closing a toner discharge port.

[0098] The replenishing toner storage 200 is shaped to discharge stored toner by rotating. For example, the replenishing toner storage 200 has a toner discharge port at one end face in the longitudinal direction, and a convex portion spirally extending toward the toner discharge port on the inner side face of the bottle body 202. Specifically, this shape includes a convex portion spirally extending from near the bottom face of the bottle body 202 toward the lid 204. The convex portion may be configured to appear convex when viewed from the inside of the bottle body 202, such as a convex portion that bulges inward from a portion of the side face of the bottle body 202; a coil-shaped member that contacts the inner side face of the bottle body 202 and spirally extends from near the bottom face of the bottle body 202 toward the lid 204; and so on.

[0099] The replenishing toner storage 200 is, for example, a toner cartridge. The specific aspects and preferred aspects of the configuration and operation of the replenishing toner storage 200 are the same as those of the rotary toner bottle 200 described later.

[0100] The replenishing toner container 200 is mounted on the replenishing toner container mounting portion 106 with its longitudinal axis oriented horizontally. The replenishing toner container mounting portion 106 includes a rotating member (eg, a gear) that rotates the replenishing toner container 200 horizontally.

[0101] The image forming apparatus includes a control unit (not shown) that transmits and receives information between the various devices (parts) and controls the operation of each device (part). For example, a developer level detection mechanism (not shown) is provided in the developing device 104. When the developer level detection mechanism detects insufficient developer, the control unit (not shown) issues a signal to rotate the rotating member (e.g., gear) of the replenishing toner storage container mounting unit 106. When the rotating member of the replenishing toner storage container mounting unit 106 rotates, the replenishing toner storage container 200 rotates, discharging toner from the discharge port of the replenishing toner storage container 200. The toner discharged from the replenishing toner storage container 200 moves through the toner supply path 108 via the replenishing toner storage container mounting unit 106, passes through the toner supply path 108, and is supplied to the developing device 104. For example, a toner remaining amount detecting mechanism (not shown) is provided in the replenishing toner container 200 . When the toner remaining amount detecting mechanism detects a shortage of the remaining toner, a replacement instruction for the replenishing toner container 200 is displayed on a display unit (not shown).

[0102] The control unit (not shown) is configured as a computer that controls the entire device and performs various calculations. Specifically, for example, the control unit includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores various programs, a RAM (Random Access Memory) used as a workspace when executing programs, a nonvolatile memory that stores various information, and an input / output (I / O) interface (none shown). The CPU, ROM, RAM, nonvolatile memory, and I / O are connected by bus bars.

[0103] In addition to a control unit, the image forming apparatus also includes an operation display unit, an image processing unit, an image memory, a storage unit, and a communication unit (none of which are shown). The operation display unit, image processing unit, image memory, storage unit, and communication unit are connected to the I / O port of the control unit. The control unit (not shown) transmits and receives information between the operation display unit, image processing unit, image memory, storage unit, and communication unit, thereby controlling each unit.

[0104] <Toner Cartridge>

[0105] The toner cartridge of this embodiment stores replenishment toner and is attached to and detached from an image forming apparatus. The toner cartridge is an example of a replenishment toner storage that stores replenishment toner to be supplied to a developing mechanism provided in the image forming apparatus.

[0106] The toner cartridge of this embodiment has a shape that discharges stored toner by rotating. One embodiment of the toner cartridge of this embodiment is a rotary toner cartridge in which a toner storage portion that stores toner rotates. Figure 3 This is a schematic structural diagram showing a rotary toner bottle as an example of a rotary toner cartridge. Figure 3 The rotary toner bottle 200 shown in FIG. 1 includes a bottle body 202, a cover 204, and a gear 206. The rotary toner bottle 200 is mounted on, for example, Figure 2 The replenishing toner storage unit 106 is shown.

[0107] The bottle body 202 is cylindrical and has a concave-convex portion 220 on the side for moving the replenishing toner toward the discharge port. The convex portion 210 provided on the concave-convex portion 220 is continuously arranged in a spiral from near the bottom surface of the bottle body 202 toward the cover 204. The convex portion 210 is arranged in a manner so as to appear convex when viewed from the inside of the bottle body 202. The convex portion 210 can be a single spiral or two or more spirals. When viewed from the inside of the bottle body 202, the portion sandwiched by adjacent convex portions 210 appears concave. In order to facilitate the movement of the replenishing toner toward the cover 204 inside the bottle body 202, it is preferred that the width of the convex portion 210 (the length in the direction of the axis Q) is narrower than the width of the adjacent concave portion (the length in the direction of the axis Q).

[0108] The bottle body 202 is made of, for example, resin. Examples of the material of the bottle body 202 include polyethylene terephthalate, polyolefin, and polyester. The bottle body 202 and the gear 206 may be integrally molded, or they may be molded separately and combined into separate molded products.

[0109] The cover 204 is provided at one end of the rotary toner bottle 200 in the direction of the axis Q. The cover 204 is provided with a discharge port 209 for discharging replenishment toner and a shutter 208 for opening and closing the discharge port 209. The discharge port 209 is opened and closed by opening and closing the shutter 208 provided on the cover 204.

[0110] The gear 206 meshes with a drive gear provided in the toner cartridge mounting portion of the image forming apparatus when the rotary toner bottle 200 is mounted in the toner cartridge mounting portion and is driven by the drive gear. Figure 3 The outer diameter of the gear 206 shown in the figure is smaller than the outer diameter of the bottle body 202. The outer diameter of the gear 206 may be the same as the outer diameter of the bottle body 202, or may be larger than the outer diameter of the bottle body 202.

[0111] Figure 3 , the bottle body 202 is provided with the concave-convex portion 220, but the toner cartridge and the rotary toner bottle of this embodiment are not limited thereto. When viewed from the outside of the bottle body 202, the side surface of the bottle body 202 may be a flat curved surface without a concave portion.

[0112] Figure 3 , the convex portion 210 is shown as a part of the bottle body 202. However, the toner cartridge and the rotary toner bottle of this embodiment are not limited to this. The convex portion 210 may also be a component separate from the bottle body 202. For example, a coil-shaped component that is provided in contact with the inner surface of the bottle body 202 and spirally extends from near the bottom surface of the bottle body 202 toward the cap 204 can be used as a separate component.

[0113] The width (length in the axis Q direction) of the convex portion 210 (width of each portion and average width) is preferably 2 mm to 10 mm, and more preferably 3 mm to 8 mm.

[0114] The height of the convex portion 210 (the height of each portion and the average height) is preferably 2 mm to 10 mm, and more preferably 3 mm to 8 mm.

[0115] The spiral period (distance in the axis Q direction) of the convex portion 210 (the spiral period of each portion and the average spiral period) is preferably 20 mm to 100 mm, more preferably 30 mm to 90 mm, and even more preferably 40 mm to 80 mm.

[0116] Next, an operation of mounting the rotary toner bottle 200 on the toner cartridge mounting portion of the image forming apparatus will be described.

[0117] The rotary toner bottle 200 is mounted on the toner cartridge mounting portion such that the gear 206 meshes with the drive gear of the toner cartridge mounting portion. At this point, the shutter 208 is opened, connecting the rotary toner bottle 200 to the toner supply path of the image forming device via the discharge port 209. By rotating the drive gear of the toner cartridge mounting portion, the gear 206 is driven to rotate, and the bottle body 202 is driven to rotate about the axis Q. The driven rotation of the bottle body 202 causes the replenishing toner to move from the bottom surface of the bottle body 202 toward the cover 204 via the concave-convex portion 220. The replenishing toner moving toward the cover 204 is discharged from the discharge port 209 and supplied to the toner supply path of the image forming device. The rotary toner bottle 200 is mounted on the toner cartridge mounting portion of the image forming device, for example, with the axis Q oriented horizontally.

[0118] <Replenishing Toner>

[0119] The replenishment toner used in the image forming apparatus and toner cartridge of this embodiment will be described in detail. This toner can be used as the toner previously loaded in the developing mechanism.

[0120] The replenishing toner contains toner particles and silica particles, wherein the number average particle size of the silica particles is greater than 110 nm and less than 130 nm, the number particle size distribution index on the large diameter side (upper side GSDp) is less than 1.080, the average roundness is greater than 0.94 and less than 0.98, and the proportion of particles with a roundness of greater than 0.92 is greater than 80%.

[0121] [Toner particles]

[0122] The toner particles are composed of, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

[0123] - Adhesive resin -

[0124] Examples of the adhesive resin include vinyl resins formed from homopolymers of the following monomers or copolymers formed by combining two or more of these monomers: styrenes (e.g., styrene, p-chlorostyrene, α-methylstyrene, etc.), (meth)acrylates (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.), and the like.

[0125] Examples of the adhesive resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these resins with the above-mentioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these resins.

[0126] These adhesive resins may be used alone or in combination of two or more.

[0127] (1) Styrene acrylic resin

[0128] As the adhesive resin, a styrene acrylic resin is suitable.

[0129] Styrene acrylic resins are copolymers formed by copolymerizing at least a styrene monomer (a monomer having a styrene skeleton) and a (meth)acrylic monomer (a monomer having a (meth)acryloyl group, preferably a monomer having a (meth)acryloyloxy group). Styrene acrylic resins include, for example, copolymers of styrene monomers and the aforementioned (meth)acrylate monomers. The acrylic resin portion of a styrene acrylic resin is a partial structure formed by polymerization of either or both acrylic and methacrylic monomers. Furthermore, the term "(meth)acrylic acid" encompasses both "acrylic acid" and "methacrylic acid."

[0130] Specific examples of the styrene-based monomers include styrene, alkyl-substituted styrenes (e.g., α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrenes (e.g., 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), and vinylnaphthalene. The styrene-based monomers may be used alone or in combination of two or more.

[0131] Among these, styrene is preferred as the styrene-based monomer from the viewpoints of easiness of reaction, easiness of reaction control, and availability.

[0132] Examples of the (meth)acrylic acid monomer include, specifically, (meth)acrylic acid and (meth)acrylic acid esters. Examples of the (meth)acrylic acid esters include, for example, (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, pentyl (meth)acrylate, neopentyl (meth)acrylate, Examples of the present invention include isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, etc.), aryl (meth)acrylates (for example, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, tert-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, etc.), dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, and (meth)acrylamide. The (meth)acrylic monomer may be used alone or in combination of two or more.

[0133] Among these (meth)acrylates, (meth)acrylates having an alkyl group with 2 to 14 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred from the perspective of improving the fixing properties of the toner. Among them, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0134] The copolymerization ratio of the styrene-based monomer to the (meth)acrylic-based monomer (based on mass, styrene-based monomer / (meth)acrylic-based monomer) is not particularly limited, but is preferably 85 / 15 to 60 / 40.

[0135] The styrene acrylic resin preferably has a cross-linked structure. Examples of the styrene acrylic resin having a cross-linked structure preferably include a resin obtained by copolymerizing at least a styrene-based monomer, a (meth)acrylic-based monomer, and a cross-linking monomer.

[0136] Examples of the crosslinkable monomer include bifunctional or higher-functional crosslinking agents.

[0137] Examples of bifunctional crosslinking agents include divinylbenzene, divinylnaphthalene, di(meth)acrylate compounds (e.g., diethylene glycol di(meth)acrylate, methylenebis(meth)acrylamide, decanediol diacrylate, glycidyl(meth)acrylate, etc.), polyester di(meth)acrylates, and 2-([1'-methylpropyleneamino]carboxyamino)ethyl methacrylate.

[0138] Examples of trifunctional or higher-functional crosslinking agents include tri(meth)acrylate compounds (e.g., pentaerythritol tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc.), tetra(meth)acrylate compounds (e.g., pentaerythritol tetra(meth)acrylate, oligoesters (meth)acrylate, etc.), 2,2-bis(4-methacryloyloxy, polyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, and diallyl chlorendic acid.

[0139] Among them, as the crosslinking monomer, from the perspective of improving the fixing property of the toner, a (meth)acrylate compound having two or more functional groups is preferred, a difunctional (meth)acrylate compound is more preferred, a difunctional (meth)acrylate compound having an alkylene group having 6 to 20 carbon atoms is further preferred, and a functional (meth)acrylate compound having a linear alkylene group having 6 to 20 carbon atoms is particularly preferred.

[0140] The copolymerization ratio of the cross-linkable monomer to all monomers (weight basis, cross-linkable monomer / all monomers) is not particularly limited, but is preferably 2 / 1,000 to 20 / 1,000.

[0141] The glass transition temperature (Tg) of the styrene acrylic resin is preferably 40° C. or higher and 75° C. or lower, and more preferably 50° C. or higher and 65° C. or lower, from the viewpoint of improving the fixing property of the toner.

[0142] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, by the "extrapolated glass transition onset temperature" method described in the glass transition temperature determination method in JIS K 7121-1987 "Plastics - Determination of Transition Temperatures".

[0143] From the viewpoint of storage stability of the toner, the weight average molecular weight of the styrene acrylic resin is preferably 5,000 to 200,000, more preferably 10,000 to 100,000, and particularly preferably 20,000 to 80,000.

[0144] The method for preparing the styrene acrylic resin is not particularly limited, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) can be applied. In addition, the polymerization reaction can be applied by known operations (e.g., batch, semi-continuous, continuous, etc.).

[0145] (2) Polyester resin

[0146] As the adhesive resin, polyester resin is preferred.

[0147] Examples of the polyester resin include known amorphous polyester resins. Among the polyester resins, an amorphous polyester resin and a crystalline polyester resin may be used in combination. The crystalline polyester resin is preferably used in an amount of 2% by mass to 40% by mass (preferably 2% by mass to 20% by mass) relative to the total binder resin.

[0148] The "crystallinity" of a resin means that there is no step-like change in endothermic value in differential scanning calorimetry (DSC) and that the resin has a clear endothermic peak. Specifically, it means that the half-value width of the endothermic peak is within 10°C when measured at a heating rate of 10 (°C / min).

[0149] On the other hand, the "amorphous" nature of a resin means that the half-value width is larger than 10°C, the resin exhibits a step-like change in endothermic value, or no clear endothermic peak is observed.

[0150] Amorphous polyester resin

[0151] Examples of the amorphous polyester resin include polycondensates of polycarboxylic acids and polyols. A commercially available amorphous polyester resin may be used, or a synthetic amorphous polyester resin may be used.

[0152] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, and naphthalene dicarboxylic acid), anhydrides thereof, and lower (e.g., C1-5) alkyl esters thereof. Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids.

[0153] Among the polycarboxylic acids, dicarboxylic acids and trivalent or higher carboxylic acids having a crosslinked structure or a branched structure may be used in combination. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower (e.g., C1-5) alkyl esters.

[0154] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0155] Examples of the polyol include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred, and aromatic diols are more preferred.

[0156] As the polyol, a diol may be used in combination with a trivalent or higher polyol having a crosslinked structure or a branched structure. Examples of the trivalent or higher polyol include glycerin, trimethylolpropane, and pentaerythritol.

[0157] The polyols may be used alone or in combination of two or more.

[0158] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower.

[0159] The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, by the "extrapolated glass transition onset temperature" method described in the glass transition temperature determination method in JIS K7121:1987 "Plastics - Determination of Transition Temperatures".

[0160] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000.

[0161] The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less.

[0162] The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.

[0163] The weight-average molecular weight and number-average molecular weight were measured by gel permeation chromatography (GPC). Molecular weight measurements using GPC were performed using a Tosoh GPC HLC-8120GPC, a Tosoh TSKgel SuperHM-M (15 cm) column, and THF as a solvent. The weight-average molecular weight and number-average molecular weight were calculated from the measurement results using a molecular weight calibration curve prepared using monodisperse polystyrene standard samples.

[0164] The amorphous polyester resin is obtained by a known production method. Specifically, for example, the polymerization temperature is set at 180° C. to 230° C., and the pressure in the reaction system is reduced as needed to allow the reaction to proceed while removing water or alcohol generated during condensation.

[0165] If the raw monomers are insoluble or incompatible at the reaction temperature, a high-boiling-point solvent can be added as a dissolution aid to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. If there are monomers with poor compatibility, these monomers can be pre-condensed with a specific acid or alcohol that is polycondensed with them, and then polycondensed with the main component.

[0166] Crystalline polyester resin

[0167] Examples of the crystalline polyester resin include polycondensates of polycarboxylic acids and polyols. As the crystalline polyester resin, commercially available products may be used, and synthetic products may also be used.

[0168] Here, in order to facilitate the formation of a crystal structure of the crystalline polyester resin, a polycondensate obtained by using a linear aliphatic polymerizable monomer is preferred over a polycondensate obtained by using a polymerizable monomer having an aromatic group.

[0169] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, or lower (e.g., carbon number 1 to 5) alkyl esters thereof.

[0170] Among polycarboxylic acids, dicarboxylic acids may be used in combination with trivalent or higher carboxylic acids having a crosslinked structure or a branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), their anhydrides, or their lower (e.g., C1-5) alkyl esters.

[0171] As the polycarboxylic acid, these dicarboxylic acids can be used in combination with a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond.

[0172] The polyvalent carboxylic acid may be used alone or in combination of two or more.

[0173] Examples of the polyol include aliphatic diols (e.g., linear aliphatic diols having a main chain portion with 7 to 20 carbon atoms). Examples of the aliphatic diol include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred.

[0174] Among the polyols, diols may be used in combination with trivalent or higher-valent alcohols having a cross-linked structure or a branched structure. Examples of the trivalent or higher-valent alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

[0175] The polyols may be used alone or in combination of two or more.

[0176] Here, the content of the aliphatic diol in the polyol is preferably 80 mol% or more, preferably 90 mol% or more.

[0177] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C.

[0178] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Plastics - Determination of Transition Temperatures”.

[0179] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0180] The crystalline polyester resin can be obtained, for example, by a known production method similar to the amorphous polyester.

[0181] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the entire toner particles.

[0182] -Colorant-

[0183] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, vat yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, sulfur-resistant orange, Vochug red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont Oil Red, pyrazolone red, litho red, rhodamine B lake, lake red C, pigment red, rose red, aniline blue, ultramarine blue, soluble blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, and various other pigments; or acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, nigrosine-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes.

[0184] The coloring agents may be used alone or in combination of two or more.

[0185] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, two or more colorants may be used in combination.

[0186] The content of the colorant is, for example, preferably from 1 mass % to 30 mass % both inclusive, and more preferably from 3 mass % to 15 mass % both inclusive, based on the entire toner particles.

[0187] -Release agent-

[0188] Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0189] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C.

[0190] The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in the method for measuring melting temperature in JIS K7121:1987 “Plastics - Determination of Transition Temperatures”.

[0191] The content of the release agent is, for example, preferably from 1 mass % to 20 mass % inclusive, and more preferably from 5 mass % to 15 mass % inclusive, based on the entire toner particles.

[0192] -Other additives-

[0193] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives may be contained in the toner particles as internal additives.

[0194] - Characteristics of toner particles, etc. -

[0195] The toner particles may be toner particles of a single-layer structure, or may be toner particles of a so-called core-shell structure composed of a core (core particle) and a coating layer (shell layer) that covers the core.

[0196] Here, the toner particles having a core-shell structure may be composed of, for example, a core portion containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing a binder resin.

[0197] The volume average particle diameter (D50v) of the toner particles is preferably from 2 μm to 10 μm, and more preferably from 4 μm to 8 μm.

[0198] Various average particle diameters and various particle size distribution indices of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter) and ISOTON-II (manufactured by Beckman Coulter) for the electrolyte.

[0199] During measurement, 0.5 mg to 50 mg of the measurement sample is added to 2 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant, and this is added to 100 ml to 150 ml of the electrolyte.

[0200] The electrolyte solution containing the suspended sample was dispersed using an ultrasonic disperser for 1 minute, and the particle size distribution of particles with a diameter ranging from 2 μm to 60 μm was measured using a Coulter Multisizer II with an aperture of 100 μm. 50,000 particles were sampled.

[0201] Relative to the particle size range (interval) divided based on the measured particle size distribution, the volume and number are respectively drawn as cumulative distributions starting from the smaller diameter side, the particle size at the cumulative 16% point is defined as the volume particle size D16v and the number particle size D16p, the particle size at the cumulative 50% point is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at the cumulative 84% point is defined as the volume particle size D84v and the number particle size D84p.

[0202] Using these values, the volume particle size distribution index (GSDv) is calculated as (D84v / D16v) 1 / 2 Calculate the particle size distribution index (GSDp) by (D84p / D16p) 1 / 2 Calculated.

[0203] The average circularity of the toner particles is preferably from 0.94 to 1.00, and more preferably from 0.95 to 0.98.

[0204] The average circularity of the toner particles is determined by (equivalent circular circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projected image)]. Specifically, it is a value measured by the following method.

[0205] First, the toner particles to be measured were collected by suction and formed into a flat stream. This stream was then momentarily flashed to obtain a still image of the particles. This image was then analyzed using a flow particle image analyzer (FPIA-3000, manufactured by Sysmex) to determine the average circularity. The number of samples used to determine the average circularity was 3,500.

[0206] When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive is removed.

[0207] <First Silica Particles>

[0208] The replenishing toner contains silica particles (also referred to as "first silica particles" in the present invention) having a number average particle size of 110 nm to 130 nm, a large diameter side number particle size distribution index (upper GSDp) of less than 1.080, an average circularity of 0.94 to 0.98, and a proportion of 80% or more of the particles having a circularity of 0.92 or more.

[0209] The number average particle size of the first silica particles is greater than or equal to 110 nm and less than or equal to 130 nm. From the perspective of suppressing the occurrence of blurring in a low-temperature and low-humidity environment and the reduction in image density in a high-temperature and high-humidity environment, it is preferably greater than or equal to 113 nm and less than or equal to 127 nm, and more preferably greater than or equal to 115 nm and less than or equal to 125 nm.

[0210] The method for making the number average particle size of the first silica particles fall within the above range is not particularly limited, and examples thereof include: for example, when the first silica particles are sol-gel silica particles, a method of adjusting the temperature or reaction time when mixing the alkali catalyst and tetraalkoxysilane in the production of the sol-gel silica particles; a method of adjusting the concentrations of the above-mentioned alkali catalyst and tetraalkoxysilane; and the like.

[0211] The large diameter side number size distribution index (upper GSDp) of the first silica particles is less than 1.080. From the perspective of suppressing the occurrence of blurring in a low-temperature and low-humidity environment and a decrease in image density in a high-temperature and high-humidity environment, it is preferably less than 1.077, and more preferably less than 1.075.

[0212] From the perspective of suppressing the occurrence of blurring in a low-temperature, low-humidity environment and a decrease in image density in a high-temperature, high-humidity environment, the small-diameter side number size distribution index (lower GSDp) of the first silica particles is preferably less than 1.080, more preferably less than 1.077, and even more preferably less than 1.075.

[0213] The method for making the upper side GSDp and the lower side GSDp in the first silica particles fall within the above-mentioned range is not particularly limited, and examples thereof include: for example, when the first silica particles are sol-gel silica particles, a method of adjusting the temperature or reaction time when mixing the base catalyst and tetraalkoxysilane in the production of the sol-gel silica particles; a method of adjusting the concentrations of the above-mentioned base catalyst and tetraalkoxysilane; and the like.

[0214] The number average particle size, upper GSDp, and lower GSDp of the first silica particles are determined as follows.

[0215] (1) The toner is dispersed in methanol, stirred at room temperature (23°C), and then treated in an ultrasonic bath to separate the external additive from the toner. The toner particles are then centrifuged to settle, and the dispersion containing the external additive is recovered. The methanol is then distilled off to remove the external additive.

[0216] (2) The external additives were dispersed in resin particles (polyester, weight-average molecular weight Mw=50,000) having a volume average particle size of 100 μm.

[0217] (3) An energy dispersive X-ray analyzer (EDX) (manufactured by Horiba, Ltd., EMAX Evolution X-Max 80mm) was used. 2 The resin particles dispersed with the external additive were observed using a scanning electron microscope (SEM) (S-4800 manufactured by Hitachi High-Technologies) and images were captured at 40,000x magnification. EDX analysis was performed to select 300 or more primary silica particles within a single field of view based on the presence of Si. SEM observation was performed under conditions of an accelerating voltage of 15 kV, an emission current of 20 μA, and a WD of 15 mm. The EDX analysis was performed under these conditions for a detection time of 60 minutes.

[0218] (4) The obtained image was introduced into an image analyzer (LUZEXIII, manufactured by NIRECO Corporation), and the area of ​​each particle was determined by image analysis.

[0219] (5) The particle size of silica is calculated as the equivalent circle diameter from the measured area value.

[0220] (6) 100 silica particles with an equivalent circle diameter of 80 nm or more were sorted out.

[0221] The cumulative distribution of the equivalent circle diameters of the separated silica particles is plotted from the smaller diameter side, and the particle diameter at the cumulative 50% point is defined as the number average particle diameter of the first silica particles.

[0222] For the silica particles separated as described above, the cumulative distribution of equivalent circle diameters was plotted from the small diameter side. The particle size at the 16% cumulative point was defined as the number average particle size D16p, the particle size at the 50% cumulative point was defined as the number average particle size D50p, and the particle size at the 84% cumulative point was defined as the number average particle size D84p. Furthermore, the number particle size distribution index on the large diameter side (upper GSDp) was calculated as (D84p / D50p). 1 / 2 Calculate the particle size distribution index on the small diameter side (lower side GSDp) by (D50p / D16p) 1 / 2 Calculated.

[0223] The average circularity of the first silica particles is 0.94 to 0.98. From the perspective of suppressing blurring in a low-temperature, low-humidity environment and reducing image density in a high-temperature, high-humidity environment, the average circularity is preferably 0.940 to 0.980, more preferably 0.945 to 0.975, and even more preferably 0.950 to 0.970.

[0224] The method for making the average circularity of the first silica particles fall within the above range is not particularly limited, and examples thereof include: for example, when the first silica particles are sol-gel silica particles, a method of adjusting the temperature or reaction time when mixing the alkali catalyst and tetraalkoxysilane in the production of the sol-gel silica particles; a method of adjusting the concentration of the above-mentioned alkali catalyst; and the like.

[0225] The proportion of silica particles having a roundness of 0.92 or greater in the first silica particles is 80% by number or greater. From the perspective of suppressing the occurrence of blurring in a low-temperature, low-humidity environment and a decrease in image density in a high-temperature, high-humidity environment, the proportion is preferably 85% by number or greater, and more preferably 87% by number or greater.

[0226] The method for bringing the proportion of silica particles having a roundness of 0.92 or greater in the first silica particles into the above range is not particularly limited, and examples thereof include: for example, when the first silica particles are sol-gel silica particles, a method of adjusting the temperature or reaction time when mixing the alkali catalyst with tetraalkoxysilane during the production of the sol-gel silica particles; a method of adjusting the concentration of the alkali catalyst; and the like.

[0227] The average circularity of the first silica particles and the ratio of silica particles having a circularity of 0.92 or greater in the first silica particles were determined as follows.

[0228] The circularity of the 100 particles sorted by the method for determining the number average particle size of the first silica particles was calculated using the following formula (1). The 50% circularity obtained by accumulating the obtained circularity from the smaller diameter side was taken as the average circularity of the first silica particles.

[0229] Formula (1): roundness = 4π × (A / I 2 )

[0230] In formula (1), I represents the perimeter of the primary particle on the image, and A represents the projected area of ​​the primary particle.

[0231] Furthermore, the ratio of the number of silica particles having a circularity of 0.92 or greater in 100 silica particles when the average circularity is calculated is defined as the ratio of the number of silica particles having a circularity of 0.92 or greater in the first silica particles.

[0232] From the perspective of suppressing the occurrence of blurring in a low-temperature, low-humidity environment and a decrease in image density in a high-temperature, high-humidity environment, the hydrophobization degree of the first silica particles is preferably 50% to 80%, more preferably 50% to 75%, and even more preferably 50% to 70%.

[0233] The method for bringing the hydrophobization degree of the first silica particles into the above-mentioned range is not particularly limited, and examples thereof include: for example, when the first silica particles are sol-gel silica particles, a method in which the surface of the silica particles is hydrophobized using a hydrophobizing agent in the presence of supercritical carbon dioxide during the production of the sol-gel silica particles is mentioned.

[0234] The hydrophobization degree of the first silica particles is determined as follows.

[0235] 0.2% by mass of silica particles as a sample were added to 50 ml of ion-exchanged water. Methanol was then added dropwise from a burette while stirring with a magnetic stirrer. The methanol mass fraction (%) in the methanol-ion-exchanged water mixed solution, at the titration endpoint where the entire sample had settled into the solution (= amount of methanol added / (amount of methanol added + amount of ion-exchanged water)), was calculated as the degree of hydrophobization (%).

[0236] The first silica particles may be particles containing silicon dioxide, i.e., SiO2, as the main component, and may be either crystalline or amorphous. The first silica particles may be particles produced using silicon compounds such as water glass and alkoxysilane as raw materials, or may be particles obtained by crushing quartz. Examples of the first silica particles include: sol-gel silica particles; aqueous colloidal silica particles; alcoholic silica particles; fumed silica particles obtained by a gas phase method; fused silica particles; and the like. Of the above, the first silica particles preferably include sol-gel silica particles.

[0237] Sol-gel silica particles can be obtained, for example, by the following method. Tetraalkoxysilane (TMOS, etc.) is dropwise added to an alkaline catalyst solution containing an alcohol compound and aqueous ammonia to hydrolyze and condense the tetraalkoxysilane, thereby obtaining a suspension containing sol-gel silica particles. The solvent is then removed from the suspension to obtain granules. The granules are then dried to obtain sol-gel silica particles.

[0238] The first silica particles may be silica particles subjected to a hydrophobic treatment using a hydrophobic treatment agent.

[0239] As the hydrophobizing treatment agent, for example, known organosilicon compounds with alkyl groups (such as methyl, ethyl, propyl, butyl, etc.) can be enumerated, and specific examples can include alkoxysilane compounds, siloxane compounds, silazane compounds, etc. Among the above, the hydrophobizing treatment agent preferably includes at least one of siloxane compounds and silazane compounds. The hydrophobizing treatment agent can be used alone or in combination with two or more.

[0240] Examples of the siloxane compound include silicone oil and silicone resin. Preferably, the silicone oil includes dimethyl silicone oil. The siloxane compound may be used alone or in combination of two or more.

[0241] Examples of the silazane compound include hexamethyldisilazane and tetramethyldisilazane. Of the above, the silazane compound preferably includes hexamethyldisilazane (HMDS). The silazane compound may be used alone or in combination of two or more.

[0242] The surface adhesion amount of the hydrophobizing agent such as the silazane compound attached to the surface of the first silica particles is preferably from 0.01% by mass to 5% by mass relative to the first silica particles, more preferably from 0.05% by mass to 3% by mass, and even more preferably from 0.10% by mass to 2% by mass, from the perspective of increasing the hydrophobization degree of the first silica particles.

[0243] As a method for hydrophobizing the first silica particles using a hydrophobizing agent, for example, there can be mentioned: a method of dissolving the hydrophobizing agent in supercritical carbon dioxide using supercritical carbon dioxide, thereby causing the hydrophobizing agent to adhere to the surface of the silica particles; a method of applying (e.g., spraying or coating) a solution containing a hydrophobizing agent and a solvent in which the hydrophobizing agent is dissolved to the surface of the silica particles in the atmosphere, thereby causing the hydrophobizing agent to adhere to the surface of the silica particles; a method of adding and maintaining a solution containing a hydrophobizing agent and a solvent in which the hydrophobizing agent is dissolved in the atmosphere to a silica particle dispersion, and then drying the mixed solution of the silica particle dispersion and the above solution.

[0244] <Other additives>

[0245] The replenishing toner may further contain other external additives (hereinafter also referred to as "other external additives") other than the first silica particles. Examples of other external additives include inorganic oxide particles. Examples of inorganic oxide particles include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4. Among the above, the inorganic oxide particles preferably include TiO2 and SiO2, i.e., titanium dioxide particles, or silica particles (hereinafter also referred to as "second silica particles").

[0246] From the viewpoint of improving the fluidity of the toner, the number average particle size of the inorganic oxide particles is preferably from 5 nm to 50 nm, and more preferably from 10 nm to 40 nm.

[0247] The number average particle size of the inorganic oxide particles is determined as follows.

[0248] (1) The toner is dispersed in methanol, stirred at room temperature (23°C), and then treated in an ultrasonic bath to separate the external additive from the toner. The toner particles are then centrifuged to settle, and the dispersion containing the external additive is recovered. The methanol is then distilled off to remove the external additive.

[0249] (2) The external additives were dispersed in resin particles (polyester, weight-average molecular weight Mw=50,000) having a volume average particle size of 100 μm.

[0250] (3) An energy dispersive X-ray analyzer (EDX) (manufactured by Horiba, Ltd., EMAX Evolution X-Max 80mm) was used. 2The resin particles dispersed with the external additive were observed using a scanning electron microscope (SEM) (S-4800 manufactured by Hitachi High-Technologies) and images were captured at 40,000x magnification. EDX analysis was then performed to select at least 300 primary inorganic oxide particles from a single field of view based on the presence of atoms (such as Si and Ti) contained in each inorganic oxide particle. SEM observation was performed under conditions of an accelerating voltage of 15 kV, an emission current of 20 μA, and a WD of 15 mm. The EDX analysis was performed under these conditions for a detection time of 60 minutes.

[0251] (4) The obtained image was introduced into an image analyzer (LUZEXIII, manufactured by NIRECO Corporation), and the area of ​​each particle was determined by image analysis.

[0252] (5) The particle size of each inorganic oxide particle is determined as an equivalent circle diameter from the measured area value.

[0253] (6) 100 particles with an equivalent circular diameter less than 80 nm were sorted out.

[0254] The cumulative distribution of the equivalent circle diameters of the particles thus sorted is plotted from the smaller diameter side, and the particle diameter at the cumulative 50% point is defined as the number average particle diameter of the inorganic oxide particles.

[0255] The surface of the inorganic oxide particles as an external additive can be subjected to a hydrophobizing treatment. The hydrophobizing treatment is carried out by, for example, immersing the inorganic oxide particles in a hydrophobizing treatment agent. The hydrophobizing treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. They can be used alone or in combination of two or more.

[0256] The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the inorganic oxide particles.

[0257] Examples of the external additives include resin particles (polystyrene, polymethyl methacrylate (PMMA), melamine resin, and other resin particles), detergent active agents (for example, particles of a fluorine-based high molecular weight body), and the like.

[0258] The amount of other external additives added is, for example, preferably from 0.01% by mass to 5% by mass, and more preferably from 0.01% by mass to 2.0% by mass, based on the toner particles.

[0259] [Toner Manufacturing Method]

[0260] The toner according to this embodiment is obtained by adding an external additive to the toner particles after producing the toner particles.

[0261] Toner particles can be produced by any of dry methods (e.g., kneading and pulverization methods) or wet methods (e.g., aggregation and coalescence methods, suspension polymerization methods, and dissolution and suspension methods). These methods are not particularly limited, and known methods can be employed. Among these, toner particles can be obtained by the aggregation and coalescence method.

[0262] Specifically, for example, in the case of producing toner particles by an agglomeration and coalescence method, the toner particles are produced through the following steps: a step of preparing a resin particle dispersion in which resin particles serving as a binding resin are dispersed (resin particle dispersion preparation step); a step of agglomerating resin particles (and other particles if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions if necessary) to form agglomerated particles (agglomerated particle formation step); and a step of heating the agglomerated particle dispersion in which the agglomerated particles are dispersed to fuse and coalesce the agglomerated particles to form toner particles (fusion and coalescence step).

[0263] The details of each step are described below.

[0264] In the following description, a method for obtaining toner particles containing a colorant and a release agent is described, but the colorant and the release agent are additives used as needed. Of course, other additives besides the colorant and the release agent may also be used.

[0265] - Resin particle dispersion preparation step -

[0266] A resin particle dispersion in which resin particles serving as a binder resin are dispersed is prepared, and at the same time, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0267] The resin particle dispersion is prepared by, for example, dispersing the resin particles in a dispersion medium using a surfactant.

[0268] Examples of the dispersion medium used in the resin particle dispersion include aqueous media.

[0269] Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols. These media may be used alone or in combination of two or more.

[0270] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols. Among these, anionic surfactants and cationic surfactants are particularly useful. Nonionic surfactants can be used in combination with anionic or cationic surfactants.

[0271] The surfactant may be used alone or in combination of two or more.

[0272] In the resin particle dispersion, as a method for dispersing the resin particles in the dispersion medium, for example, common dispersion methods using a rotary shearing homogenizer or a ball mill, sand mill, bead mill, etc. with a medium can be cited. In addition, depending on the type of resin particles, the resin particles can also be dispersed in the dispersion medium using a phase inversion emulsification method. The phase inversion emulsification method is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent that can dissolve the resin, a base is added to the organic continuous phase (O phase) for neutralization, and then an aqueous medium (W phase) is added to thereby invert the phase from W / O to O / W, so that the resin is dispersed in the aqueous medium in the form of particles.

[0273] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less.

[0274] The volume average particle size of the resin particles is determined using a particle size distribution obtained by measurement using a laser diffraction particle size analyzer (e.g., LA-700 manufactured by Horiba, Ltd.). For the defined particle size range (interval), a cumulative distribution is plotted with respect to volume, starting from the smaller particle size side. The particle size at the cumulative 50% point relative to all particles is measured and designated as the volume average particle size D50v. The volume average particle size of particles in other dispersions is similarly measured.

[0275] The content of the resin particles contained in the resin particle dispersion is preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0276] For example, a colorant particle dispersion and a release agent particle dispersion are prepared in the same manner as the resin particle dispersion. Specifically, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0277] - Agglomerated Particle Formation Step-

[0278] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0279] Thereafter, the resin particles, the colorant particles, and the release agent particles are heterogeneously aggregated in the mixed dispersion to form aggregated particles containing the resin particles, the colorant particles, and the release agent particles and having a diameter close to that of the target toner particles.

[0280] Specifically, for example, a coagulant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, pH 2 or higher and pH 5 or lower), a dispersion stabilizer is added as needed, and then heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles is not less than -30°C and the glass transition temperature is not more than -10°C), so that the particles dispersed in the mixed dispersion are agglomerated to form agglomerated particles.

[0281] In the aggregated particle formation step, for example, a coagulant can be added to the mixed dispersion at room temperature (e.g., 25° C.) while stirring the mixed dispersion using a rotary shearing homogenizer, the pH of the mixed dispersion can be adjusted to acidic (e.g., pH 2 to 5), and a dispersion stabilizer can be added as needed, followed by heating.

[0282] Examples of the coagulant include surfactants with opposite polarity to the surfactant contained in the mixed dispersion, inorganic metal salts, and divalent or higher metal complexes. When a metal complex is used as the coagulant, the amount of surfactant used is reduced, and charging characteristics are improved.

[0283] If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant can be used together with the coagulant. As such an additive, a chelating agent is preferably used.

[0284] Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

[0285] As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like.

[0286] The amount of the chelating agent added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the resin particles.

[0287] - Fusion and coalescence step -

[0288] Next, the aggregated particle dispersion containing the dispersed aggregated particles is heated to a temperature equal to or higher than the glass transition temperature of the resin particles (e.g., 10°C to 30°C higher than the glass transition temperature of the resin particles) to fuse and coalesce the aggregated particles to form toner particles.

[0289] After the above steps, toner particles are obtained.

[0290] After obtaining a dispersion of aggregated particles in which aggregated particles are dispersed, colorant particles can be manufactured by the following steps: further mixing the aggregated particle dispersion with a resin particle dispersion in which resin particles are dispersed, and agglomerating the resin particles so as to further adhere to the surface of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and aggregate the second aggregated particles to form colorant particles with a core-shell structure.

[0291] After the fusion and coalescence steps are completed, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying steps to obtain dry toner particles. For the washing step, displacement washing using ion-exchanged water is suitable for charging performance. For the solid-liquid separation step, suction filtration, pressure filtration, etc. are suitable for productivity. For the drying step, freeze drying, airflow drying, fluidized bed drying, vibrating fluidized bed drying, etc. are suitable for productivity.

[0292] The toner of this embodiment is then produced by, for example, adding an external additive to the resulting dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, Henschel mixer, or Loedige mixer. Furthermore, if necessary, coarse toner particles can be removed using a vibrating screen or pneumatic screen.

[0293] <Electrostatic Image Developer>

[0294] The replenishing toner stored in the replenishing toner storage of the image forming apparatus of this embodiment is replenished to the developing mechanism and used as an electrostatic image developer for image formation. The electrostatic image developer contains at least the replenishing toner. The electrostatic image developer may be a single-component developer containing only the replenishing toner, or a two-component developer containing the replenishing toner mixed with a carrier.

[0295] The carrier is not particularly limited, and known carriers can be used. Examples of carriers include coated carriers in which a core material composed of magnetic powder is coated with a resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed and mixed in a matrix resin; and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. Magnetic powder-dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier serve as a core material and are coated with a resin.

[0296] Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0297] Examples of the coating resin and base resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, straight silicone resin containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, epoxy resins, and the like. The coating resin and base resin may contain other additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0298] When utilizing the surface of the resin coating core material, can cite: utilize the method that coating is carried out with the solution formed by dissolving the coating resin and various additives (used as needed) in a suitable solvent etc.. As solvent, there is no particular limitation, consider the kind of resin used, coating suitability etc. and select and get final product.

[0299] Specific resin coating methods include: an immersion method, in which the core material is immersed in a coating layer forming solution; a spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; a fluidized bed method, in which the coating layer forming solution is sprayed while the core material is suspended by flowing air; a kneading coater method, in which the core material of the carrier is mixed with the coating layer forming solution in a kneading coater and the solvent is then removed; and the like.

[0300] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner:carrier=1:100 to 30:100, more preferably 3:100 to 20:100.

[0301] [Example]

[0302] The following examples illustrate embodiments of the present invention in detail, but the present invention is not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0303] <Production of Silica Particles>

[0304] [Preparation of Silica Particle Dispersion (1)]

[0305] 300 parts of methanol and 70 parts of 10% ammonia water were added to a glass reaction container equipped with a stirrer, a dripper, and a thermometer and mixed to obtain an alkali catalyst solution. After adjusting the alkali catalyst solution to 30°C, 185 parts of tetramethoxysilane and 50 parts of 8% ammonia water were added dropwise while stirring to obtain a hydrophilic silica particle dispersion (solid content 12%). Here, the addition time (the length of time the tetramethoxysilane and ammonia water were added dropwise to the alkali catalyst solution) was set to 30 minutes. Thereafter, the obtained silica particle dispersion was concentrated to a solid content of 40% using a rotary filter R-Fine (manufactured by Kotobuki Industry Co., Ltd.). This concentrate was designated as silica particle dispersion (1).

[0306] [Preparation of Silica Particle Dispersions (2) to (8) and (c1) to (c6)]

[0307] In the preparation of the silica particle dispersion (1), silica particle dispersions (2) to (8) and (c1) to (c6) were prepared in the same manner as the silica particle dispersion (1), except that the amount of ammonia water in the alkaline catalyst solution, the total amount of tetramethoxysilane added dropwise, the total amount of ammonia water added dropwise, the dropping time, and the dropping start temperature (the temperature at which the dropping of tetramethoxysilane and ammonia water was started) in the silica particle production conditions were changed according to Table 1.

[0308] [Preparation of Silica Particles (S1)]

[0309] The silica particles were surface-treated with a siloxane compound using the silica particle dispersion (1) in a supercritical carbon dioxide atmosphere as follows. The surface treatment was performed using an apparatus equipped with a carbon dioxide tank, a carbon dioxide pump, an entrainer pump, an autoclave (500 ml capacity) with a stirrer, and a pressure valve.

[0310] First, 300 parts of the silica particle dispersion (1) were placed in an autoclave (500 ml capacity) equipped with a stirrer, and the stirrer was rotated at 100 rpm. Liquefied carbon dioxide was then injected into the autoclave, and the temperature was raised using a heater and the pressure was simultaneously increased using a carbon dioxide pump, so that the autoclave reached a supercritical state of 150° C. and 15 MPa. While maintaining the pressure in the autoclave at 15 MPa using a pressure valve, supercritical carbon dioxide was circulated by a carbon dioxide pump to remove methanol and water from the silica particle dispersion (1) (solvent removal step), thereby obtaining silica particles (untreated silica particles).

[0311] Next, when the amount of supercritical carbon dioxide (cumulative amount: measured based on the amount of carbon dioxide in a standard state) reached 900 parts, the flow of supercritical carbon dioxide was stopped.

[0312] Subsequently, a heater maintained the temperature at 150°C and a carbon dioxide pump maintained the pressure at 15 MPa, maintaining a supercritical carbon dioxide state within the autoclave. In this state, an entrainer pump was used to inject a treatment solution into the autoclave. This treatment solution was prepared by dissolving 0.3 parts of dimethyl silicone oil (DSO: trade name "KF-96 (Shin-Etsu Chemical Co., Ltd.") with a viscosity of 10,000 cSt, a siloxane compound, in 20 parts of hexamethyldisilazane (HMDS; manufactured by Organic Synthetic Chemicals Co., Ltd.), a hydrophobizing agent, per 100 parts of the aforementioned silica particles (untreated silica particles). The reaction was then stirred at 180°C for 20 minutes. Supercritical carbon dioxide was then recirculated to remove any remaining treatment solution. Stirring was then stopped, the pressure in the autoclave was released to atmospheric pressure by opening the pressure valve, and the temperature was lowered to room temperature (25°C).

[0313] The solvent removal step and the surface treatment with HMDS and DSO were sequentially performed in this manner to obtain silica particles (S1) surface-treated with a hydrophobizing agent.

[0314] [Preparation of Silica Particles (S2) to (S8) and (cS1) to (cS6)]

[0315] Silica particles (S2) to (S8) and (cS1) to (cS6) surface-treated with a hydrophobizing agent were obtained in the same manner as in the preparation of the silica particles (S1).

[0316] [Preparation of Silica Particles (cS7) to (cS8)]

[0317] Hydrophobic silica particles (cS7) were obtained in the same manner as in paragraphs 0051 to 0053 of JP-A-2008-174430. Furthermore, hydrophobic silica particles (cS8) were obtained in the same manner as in paragraph 0019 of JP-A-2001-194824.

[0318] [Table 1]

[0319]

[0320] <Preparation of Particle Dispersion>

[0321] [Preparation of Amorphous Polyester Resin Particle Dispersion (A1)]

[0322] Terephthalic acid: 70 parts

[0323] Fumaric acid: 30 parts

[0324] Ethylene glycol: 45 parts

[0325] 1,5-Pentanediol: 46 parts

[0326] The above materials were placed in a flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column. The temperature was raised to 220°C over 1 hour under a nitrogen stream. One part of tetraethoxytitanium was added to 100 parts of the above materials. While distilling off the generated water, the temperature was raised to 240°C over 0.5 hours. Dehydration condensation was continued at this temperature for another hour, and the reaction mixture was cooled. This produced a polyester resin with a weight-average molecular weight of 9,500 and a glass transition temperature of 62°C.

[0327] A mixed solvent consisting of 40 parts ethyl acetate and 25 parts 2-butanol was added to a container equipped with a temperature control mechanism and a nitrogen displacement mechanism. After preparing a solvent mixture, 100 parts of a polyester resin was slowly added and dissolved. A 10% aqueous ammonia solution (equivalent to 3 times the acid value of the resin in terms of molar ratio) was then added and stirred for 30 minutes. The container was then purged with dry nitrogen, the temperature maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / minute to emulsify the mixture while stirring. After the addition was complete, the emulsion was returned to 25°C to obtain a resin particle dispersion containing resin particles having a volume average particle size of 200 nm. Ion-exchanged water was added to this resin particle dispersion to adjust the solids content to 20%, thereby producing an amorphous polyester resin particle dispersion (A1).

[0328] [Preparation of Crystalline Polyester Resin Particle Dispersion (C1)]

[0329] 1,10-Decanedicarboxylic acid: 98 parts

[0330] ·Sodium 5-sulfoisophthalate dimethyl ester: 24 parts

[0331] 1,9-nonanediol: 100 parts

[0332] Dibutyltin oxide (catalyst): 0.3 parts

[0333] The above ingredients were added to a heat-dried three-necked flask. The atmosphere in the container was then inertized with nitrogen by decompression. The mixture was stirred and refluxed at 180°C for 5 hours using a mechanical stirrer. The mixture was then slowly heated to 230°C under reduced pressure and stirred for 2 hours. Once the mixture reached a viscous state, it was air-cooled to terminate the reaction and produce a crystalline polyester resin. Molecular weight measurement (polystyrene equivalent) revealed a weight-average molecular weight (Mw) of 9700 and a melting point of 78°C.

[0334] 90 parts of the obtained crystalline polyester resin, 1.8 parts of anionic surfactant NEOGEN RK (Daiichi Kogyo Seiyaku), and 210 parts of ion-exchanged water were heated to 100°C, dispersed using an ULTRA-TURRAXT50 manufactured by IKA, and then dispersed using a pressure-dispensing Gaulin homogenizer for 1 hour to prepare a crystalline polyester resin particle dispersion (C1) having a volume average particle size of 200 nm and a solid content of 20%.

[0335] [Preparation of Release Agent Particle Dispersion]

[0336] Solid paraffin wax (HNP-9 manufactured by Nippon Seira Co., Ltd.): 100 parts

[0337] Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part

[0338] Ion exchange water: 350 parts

[0339] The above materials were mixed and heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed using a Manton Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent particle dispersion (solid content 20%) in which release agent particles with a volume average particle size of 200 nm were dispersed.

[0340] [Preparation of Black Colored Particle Dispersion]

[0341] Carbon black (Regal 330, manufactured by Cabot Corporation): 50 parts

[0342] Anionic surfactant NEOGEN RK (Daiichi Industrial Pharmaceutical): 5 parts

[0343] Ion exchange water: 192.9 parts

[0344] The above components were mixed and treated with an Ultimaizer (manufactured by Sugino Machine Co., Ltd.) at 240 MPa for 10 minutes to prepare a black colored particle dispersion (solid content 20%).

[0345] <Preparation of Toner Particles>

[0346] [Preparation of Toner Particles (A1)]

[0347] Ion exchange water: 200 parts

[0348] Amorphous polyester resin particle dispersion (A1): 150 parts

[0349] Crystalline polyester resin particle dispersion (C1): 10 parts

[0350] Black coloring particle dispersion: 15 parts

[0351] Release agent particle dispersion: 10 parts

[0352] Anionic surfactant (TaycaPower): 2.8 parts

[0353] The above materials were placed in a round stainless steel flask, and after adding 0.1N nitric acid to adjust the pH to 3.5, an aqueous solution of polyaluminum chloride (PAC, manufactured by Oji Paper Co., Ltd.: 30% powder) (2.0 parts) dissolved in 30 parts of ion-exchanged water was added. Dispersed at 30°C using a homogenizer (ULTRA-TURRAXT 50, manufactured by IKA Co., Ltd.), the mixture was heated to 45°C in a heating oil bath and maintained until the volume average particle size reached 4.8 μm. Subsequently, 60 parts of the amorphous polyester resin particle dispersion (A1) was added and maintained for 30 minutes. After the volume average particle size reached 5.2 μm, another 60 parts of the amorphous polyester resin particle dispersion (A1) was added and maintained for 30 minutes. Subsequently, 20 parts of a 10% aqueous solution of NTA (nitrilotriacetic acid) metal salt (Chelest 70, manufactured by Chelest Co., Ltd.) was added, and the pH was adjusted to 9.0 using a 1N aqueous sodium hydroxide solution. 1.0 part of an anionic surfactant (Tayca Power) was then added, and the mixture was heated to 85°C while continuing to stir and maintained for 5 hours. The mixture was then cooled to 20°C at a rate of 20°C / min, filtered, thoroughly washed with ion-exchanged water, and dried to obtain toner particles (A1) having a volume average particle size of 6.0 μm.

[0354] <Preparation of Toner>

[0355] [Preparation of Toner (A1)]

[0356] 100 parts of toner particles (A1), 1.5 parts of silica particles (S1), and 0.5 parts of titanium dioxide particles having a number average particle size of 20 nm as inorganic oxide particles were mixed, and mixed at a rotation speed of 13,000 rpm for 30 seconds using a sample mill. The mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain toner (A1).

[0357] [Preparation of Toners (A2) to (A8) and (cA1) to (cA8)]

[0358] Each toner was obtained in the same manner as in the toner (A1) except that the type of silica particles had the specifications shown in Table 2.

[0359] <Preparation of Developer>

[0360] [Preparation of Developers (A1) to (A8) and (cA1) to (cA8)]

[0361] 10 parts of each toner and 100 parts of the following resin-coated carrier were placed in a V-type blender and stirred for 20 minutes, and then sieved with a vibrating sieve with a mesh size of 212 μm to obtain a developer.

[0362] Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts

[0363] Toluene: 14 parts

[0364] Polymethyl methacrylate: 2 parts

[0365] Carbon black (VXC72: manufactured by Cabot): 0.12 parts

[0366] The above materials, excluding the ferrite particles, were mixed with glass beads (1 mm in diameter, equivalent in amount to toluene) and stirred at 1200 rpm for 30 minutes using a sand mill manufactured by Kansai Paint Co., Ltd. to obtain a dispersion. This dispersion and the ferrite particles were placed in a vacuum degassing kneader and dried under reduced pressure while stirring to obtain a resin-coated carrier.

[0367] <Performance Evaluation>

[0368] Prepare Figure 3 The rotary toner bottle shown in the figure has a body diameter of 110 mm and a capacity of 4012 cm 3 A spiral convex portion was formed on the inner side of the bottle body. The convex portion had an average width of 3.5 mm, an average height of 4.5 mm, and an average spiral period of 80 mm. The rotary toner bottle was filled with the toner of each example and installed in a modified image forming apparatus (model D136) manufactured by Fuji Xerox. The developer of the image forming apparatus was then filled with the developer of each example.

[0369] [Occurrence of blur in low temperature and low humidity environments]

[0370] The image forming apparatus was placed in an environment with a temperature of 10°C and a relative humidity of 10% for 24 hours to control temperature and humidity. After this conditioning, imaging was performed continuously on 100,000 sheets of A4-sized paper. A 20 cm x 25 cm image with 100% density was formed on the upper longitudinal portion of the paper, and Roman characters A to Z were formed in MS Gothic font, 14 points, and half-width on the lower portion. The text on the 100,000th sheet was visually inspected and graded according to the following criteria.

[0371] A: Toner blurring is not observed around characters.

[0372] B: Toner fogging is slightly observed around the characters, but it is very slight and does not hinder practical use.

[0373] C: Toner smearing was observed around the characters, and the product was not suitable for practical use.

[0374] [Decrease in image density under high temperature and high humidity conditions]

[0375] The image forming apparatus was placed in an environment at 30°C and 85% relative humidity for 24 hours to control temperature and humidity. After this control, imaging was performed continuously on 100,000 sheets of A4-size paper. The images were halftone images with an area ratio of 90% and an image density of 30%. The halftone image on the 100,000th sheet was visually inspected and graded according to the following criteria.

[0376] A: The entire image has sufficient density and no density unevenness.

[0377] B: There are portions with low concentration, but the concentration unevenness is slight and does not hinder practical use.

[0378] C: The overall image density is low, or there is unacceptable density unevenness.

[0379]

Claims

1. An image forming apparatus comprising: Image holding body; a charging mechanism for charging the surface of the image holding member; an electrostatic image forming mechanism for forming an electrostatic image on the surface of the charged image holding member; a developing mechanism storing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holding member into a toner image using the electrostatic image developer; a transfer mechanism for transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; a fixing mechanism for fixing the toner image transferred to the surface of the recording medium; a replenishing toner storage having no toner stirring mechanism, storing replenishing toner for replenishing the developing mechanism and discharging the replenishing toner by rotating; a replenishing toner storage mounting portion for mounting the replenishing toner storage and rotating the replenishing toner storage; and The toner supply path connects the replenishing toner storage installation portion and the developing mechanism to supply the replenishing toner to the developing mechanism. The replenishing toner contains toner particles and silica particles, wherein the silica particles have a number average particle size of 110 nm to 130 nm, an upper GSDp (Gross Dynamics Distribution) index on the large diameter side of the silica particles is less than 1.080, an average circularity of 0.94 to 0.98, and a proportion of particles having a circularity of 0.92 or greater of 80% by number. The toner particles contain an amorphous polyester resin as a binding resin.

2. The image forming apparatus according to claim 1, wherein The silica particles have a large diameter number size distribution index, that is, an upper GSDp, which is less than 1.

075.

3. The image forming apparatus according to claim 1, wherein The silica particles have a lower GSDp, which is an index of the number size distribution on the smaller diameter side, of less than 1.

080.

4. The image forming apparatus according to any one of claims 1 to 3, wherein The silica particles have an average circularity of 0.95 or more and 0.97 or less.

5. The image forming apparatus according to any one of claims 1 to 3, wherein The silica particles have a circularity of 0.92 or greater in a ratio of 85% by number or greater.

6. The image forming apparatus according to any one of claims 1 to 3, wherein The replenishment toner further contains inorganic oxide particles having a number average particle size of 5 nm to 50 nm.

7. The image forming apparatus according to any one of claims 1 to 3, wherein The above toner particles further contain a crystalline polyester resin as a binding resin.

8. The image forming apparatus according to claim 7, wherein: The toner particles contain the crystalline polyester resin in an amount of 2% by mass to 40% by mass of the entire binding resin.

9. The image forming apparatus according to any one of claims 1 to 3, wherein The toner storage portion of the replenishing toner container is made of polyethylene terephthalate or polyolefin.

10. The image forming apparatus according to any one of claims 1 to 3, wherein The replenishing toner storage has a toner discharge port at one end surface in the longitudinal direction, and has a convex portion spirally continuous toward the toner discharge port on an inner side surface of the toner storage portion.

11. The image forming apparatus according to claim 10, wherein: The average width of the convex portion is greater than or equal to 2 mm and less than or equal to 10 mm, the average height is greater than or equal to 2 mm and less than or equal to 10 mm, and the average spiral period is greater than or equal to 20 mm and less than or equal to 100 mm.

12. The image forming apparatus according to any one of claims 1 to 3, wherein The replenishing toner storage is mounted on the replenishing toner storage mounting portion with its longitudinal axis aligned horizontally. The replenishing toner container mounting portion rotates the replenishing toner container in a horizontal direction.

13. A toner cartridge that is mounted and removed from an image forming apparatus and does not include a toner stirring mechanism, wherein: The toner cartridge stores replenishing toner, the replenishing toner containing toner particles and silica particles, the silica particles having a number average particle size of 110 nm to 130 nm, a large diameter side number particle size distribution index (GSDp) of less than 1.080, an average circularity of 0.94 to 0.98, and a proportion of particles having a circularity of 0.92 or greater of 80% by number or greater. The toner particles contain an amorphous polyester resin as a binder resin. The toner cartridge discharges the replenishment toner by rotating.

Images