JP6955395B2 - Toner, two-component developer, toner cartridge and developing tank - Google Patents

Description

The present disclosure relates generally to toner, a two-component developer, a toner cartridge and a developing tank, and more specifically to a toner, a two-component developing agent containing toner, a toner cartridge including the toner, and a developing tank housed in an image forming apparatus. ..

Conventionally, as a toner for developing an electrostatic charge image in an electrophotographic method or the like, Patent Document 1 discloses a toner in which an external additive is attached to the surface of a toner base containing at least a binder resin and a colorant. ing. In this toner, metal oxide fine particles are used as an external additive to form a resin film of resin particles having a glass transition temperature of 65 ° C. or higher and 120 ° C. or lower on the surface of the metal oxide fine particles on the surface of the toner base. ..

Japanese Unexamined Patent Publication No. 2009-210996

However, in the case of a toner in which an external additive is attached to the surface of the toner matrix particles (toner matrix) as in Patent Document 1, for example, when the toner is stressed in the developing tank, the external additive is attached to the toner matrix particles. May be buried. When the external additive is embedded in the toner mother particles, the spacer effect of the external additive is lost, which may lead to defects such as carrier development or development memory during image formation.

The present disclosure has been made in view of the above reasons, and an object of the present invention is to provide a toner, a two-component developer, a toner cartridge, and a developing tank in which embedding of an external additive in toner mother particles is less likely to occur.

The toner according to one aspect of the present disclosure is a toner containing a plurality of toner particles. Each of the plurality of toner particles has a toner mother particle and an external additive attached to the toner mother particle. The toner mother particles include an amorphous resin and a crystalline resin. The adhesion strength of the external additive to the toner matrix particles is less than 75%.

The two-component developer according to one aspect of the present disclosure contains the toner and a carrier.

The toner cartridge according to one aspect of the present disclosure includes the toner and a container body for accommodating the toner.

The developing tank according to one aspect of the present disclosure is a developing tank housed in an image forming apparatus. The developing tank includes the two-component developing agent and a tank body for accommodating the two-component developing agent.

The present disclosure has an advantage that the embedding of the external additive in the toner matrix particles is less likely to occur.

FIG. 1 is a schematic cross-sectional view showing a toner according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing a carrier according to an embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view showing a two-component developer according to an embodiment of the present disclosure. FIG. 4 is a schematic perspective view showing the appearance of an image forming apparatus capable of using the same two-component developer. FIG. 5 is a schematic cross-sectional view showing the internal configuration of the image forming apparatus of the above. FIG. 6 is a schematic view showing a chart for confirming the development memory.

(1) Outline In Patent Document 1, since the external additive on the surface of the toner matrix is coated with the softened resin particles, the release of the external additive from the surface of the toner matrix is suppressed. As a result, it is possible to reduce a phenomenon (so-called carrier contamination) in which the external additive detached from the surface of the toner base adheres to the surface of the carrier and causes a decrease in the charging performance of the carrier.

By the way, an image forming unit of a general image forming apparatus includes a developing unit including a developing magnet roller and a photoconductor drum. The developing magnet roller of the developing unit attaches a charged toner to an electrostatic latent image formed on the surface of the photoconductor drum, and visualizes the electrostatic latent image to form a toner image. In this case, when the toner density changes on the developing magnet roller, the developed image density changes at the portion where the toner density changes, so that it is required to develop the photoconductor drum so that the toner density becomes uniform. Therefore, in the image forming section, the toner and the carrier are sufficiently agitated to make the toner concentration uniform, and then the toner is supplied to the surface of the photoconductor drum by the developing magnet roller.

However, if the release of the external additive from the surface of the toner base is suppressed as in Patent Document 1, the toner is difficult to separate from the surface of the developing magnet roller, and the toner is developed again from the developing magnet roller to the surface of the photoconductor drum. May be used for. Then, an image defect in which the image density becomes non-uniform in the portion where the toner density changes, that is, a development memory which is one of the live-action characteristics may occur.

Therefore, the toner according to the present embodiment obtains a spacer effect and suppresses the generation of a developing memory in the following manner while achieving both low-temperature fixability and ensuring storage stability.

That is, the toner 1 according to the present embodiment includes a plurality of toner particles 11. Each of the plurality of toner particles 11 has a toner mother particle 12 and an external additive 13 adhering to the toner mother particle 12. The toner mother particles 12 include an amorphous resin 16 and a crystalline resin 17. Since the particles made of the crystalline resin 17 are dispersed in the matrix made of the amorphous resin 16, it is possible to achieve both low-temperature fixability of the toner 1 and ensuring storage stability.

When the particles made of the crystalline resin 17 are dispersed in the matrix made of the amorphous resin 16, the external additive 13 may be embedded in the toner mother particles 12, but the external addition to the toner mother particles 12 If the adhesion strength of the agent 13 is adjusted to a predetermined value, the embedding of the external additive 13 can be suppressed. In this case, the adhesion strength of the external additive 13 to the toner mother particles 12 is less than 75%. With such an adhesion strength, even if the particles made of the crystalline resin 17 are dispersed in the matrix made of the amorphous resin 16, the external additive 13 is less likely to be embedded in the toner mother particles 12. , Spacer effect can be obtained. Thanks to this effect, the generation of developing memory can be suppressed.

(2) Details Hereinafter, the toner 1, the carrier 2, the two-component developer 3, the toner cartridge 4, and the developing tank 5 according to the present embodiment will be described in detail, and an example of an image forming apparatus 100 in which these are used will be described. explain.

(2.1) Basic Structure of Toner As shown in FIG. 1, the toner 1 contains a plurality of toner particles 11. That is, the toner 1 is a powder composed of a plurality of toner particles 11.

Each of the plurality of toner particles 11 has a toner mother particle 12 and an external additive 13. The external additive 13 is attached to the toner mother particles 12. Specifically, the external additive 13 is attached to the outer surface of the toner mother particles 12.

The volume average particle diameter of the toner mother particles 12 is not particularly limited, but is, for example, in the range of 5.0 μm or more and 10.0 μm or less.

The toner mother particles 12 include an amorphous resin 16 and a crystalline resin 17. That is, the toner mother particles 12 include both the amorphous resin 16 and the crystalline resin 17, which are thermoplastic resins. The crystalline resin 17 is in the form of particles and is dispersed in the matrix composed of the amorphous resin 16. The amorphous resin 16 mainly plays a role as a binder resin, and the particles made of the crystalline resin 17 dispersed in the matrix phase of the binder resin ensure the low-temperature fixability and storage stability of the toner 1. Can be achieved at the same time. That is, since the crystalline resin 17 has a low melting point component (melting point is, for example, 80 to 90 ° C.), it is possible to obtain toner 1 that can be easily melted and fixed by heating at a low temperature. Further, since the particles of the crystalline resin 17 are dispersed in the matrix phase of the amorphous resin 16, the toner 1 is less likely to be fused even under high temperature and high humidity conditions, and the storage stability is improved.

The amorphous resin 16 preferably contains an amorphous polyester resin. The amorphous polyester resin can be obtained by polycondensing a dicarboxylic acid monomer containing terephthalic acid or isophthalic acid as a main component and a diol monomer containing ethylene glycol as a main component.

The crystalline resin 17 preferably contains a crystalline polyester resin. The crystalline polyester resin is obtained by polycondensing a dicarboxylic acid monomer containing an aliphatic dicarboxylic acid having 9 to 22 carbon atoms as a main component and a diol monomer containing an aliphatic diol having 2 to 10 carbon atoms as a main component. Can be done. Since this crystalline polyester resin is composed of a linear saturated aliphatic polyester unit, it becomes difficult for the crystalline polyester resin and the amorphous polyester resin to be compatible with each other.

The content of the crystalline resin 17 is preferably in the range of 3 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the amorphous resin 16. When the content of the crystalline resin 17 is 3 parts by mass or more, the low temperature fixability can be improved. When the content of the crystalline resin 17 is 10 parts by mass or less, the storage stability of the toner 1 can be improved.

Further, the toner mother particles 12 may contain a colorant 6, a charge control agent 7 (CCA: Charge Control Agent), a mold release agent 8, and the like. Ingredients other than the external additive 13 are also collectively referred to as an internal additive.

As the colorant 6, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like used in the field of electrophotographic can be used.

As the charge control agent 7, a charge control agent for positive charge control and negative charge control used in the electrophotographic field can be used.

As the release agent 8, wax used in the electrophotographic field can be used.

In the present embodiment, the adhesion strength of the external additive 13 to the toner matrix particles 12 is less than 75%, preferably 70% or less.

Here, the adhesive strength of the external additive 13 to the toner mother particles 12 will be described. When a certain amount of energy is applied to the toner 1, some of the toner particles 11 remain with the external additive 13 attached, and the remaining toner particles 11 are separated from the external additive 13 to become toner mother particles 12. Therefore, the adhesive strength of the external additive 13 is the total amount of the toner particles 11 before the constant energy is applied, and the adhesive strength of the toner particles 11 that remains in the state where the external agent 13 is attached even after the constant energy is applied. It can be defined as a percentage of the total amount.

Specifically, the adhesive strength of the external additive 13 can be measured as follows. First, toner 1 is added to an aqueous solution of a surfactant having a predetermined concentration. The reason for adding the surfactant is to prevent the toner 1 from agglomerating. Next, a process of giving a constant energy to this aqueous solution is performed. This process is, for example, a process of stirring the aqueous solution or irradiating the aqueous solution with ultrasonic waves. The intensity of the element (for example, Si in the case of silica) in the external additive 13 of the toner 1 before and after this treatment is measured by fluorescent X-ray analysis. The ratio of the strength after the treatment to the strength before the treatment obtained as a result is the adhesion strength of the external additive 13. More detailed measurement methods and measurement conditions will be described in the column of Examples.

In particular, when the crystalline resin 17 becomes particles and is dispersed in the matrix composed of the amorphous resin 16, when the two-component developer 3 is stressed by being stirred in the developing tank 5 or the like. In addition, the external additive 13 is easily embedded in the toner mother particles 12. This embedding can be suppressed by appropriately adjusting the adhesion strength of the external additive 13 to the toner matrix particles 12. Specifically, when the adhesion strength of the external additive 13 to the toner mother particles 12 is less than 75%, it becomes difficult for the external additive 13 to be embedded in the toner mother particles 12, and a spacer effect can be obtained. The spacer effect is an effect that the external additive 13 acts as a spacer and can keep the distance between the toner particles 11 and the carrier particles 21 constant. Thanks to this effect, it is possible to suppress an increase in van der Waals force between the toner particles 11 and the carrier particles 21, suppress the adhesion of the toner particles 11 to the carrier particles 21, and charge the toner particles 11. The granting ability can be maintained. As a result, the generation of development memory can be suppressed.

The adhesive strength of the external additive 13 is preferably more than 36%, more preferably 40% or more. When the adhesion strength of the external additive 13 is more than 36%, filming can be suppressed. That is, the toner 1 is less likely to remain on the photoconductor drum 121 (see FIG. 5) after transfer to the recording paper.

The content of the external additive 13 is in the range of 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner mother particles 12. When the content of the external additive 13 is 1 part by mass or more, it becomes easy to secure the fluidity of the toner 1. When the content of the external additive 13 is 5 parts by mass or less, it is possible to suppress the inhibition of fixability.

As the external additive 13, known ones can be used. For example, silica and titanium oxide can be mentioned. In particular, the external additive 13 is preferably silica. It is possible to suppress the generation of developing memory as compared with the case of using other ones.

The external additive 13 preferably contains a first external additive 14 and a second external additive 15 having a smaller primary average particle size than the first external additive 14. The spacer effect can be obtained by the first external additive 14 having a larger primary average particle size than the second external additive 15. On the other hand, the second external additive 15 has a function of improving the fluidity of the toner 1 and the dispersibility of the external additive 13.

The primary average particle size of the first external additive 14 is preferably in the range of 30 nm or more and less than 200 nm, and more preferably 30 nm or more and 170 nm or less. When the primary average particle size of the first external additive 14 is 30 nm or more, the spacer effect can be easily obtained. When the primary average particle size of the first external additive 14 is less than 200 nm, the charge stability can be ensured. That is, even if printing is performed on a predetermined number of recording sheets, the charge amount of the toner 1 is less likely to decrease.

The primary average particle size of the second external additive 15 is preferably less than 30 nm, more preferably 16 nm or less. When the primary average particle size of the second external additive 15 is less than 30 nm, the charge stability can be improved.

The average circularity of the toner matrix particles 12 is preferably more than 0.925 and less than 0.956, and more preferably in the range of 0.930 or more and 0.950 or less. Here, the average circularity of the toner mother particles 12 can be obtained as follows. For example, in the projected image of the toner mother particles 12 detected by the flow type particle image analyzer (manufactured by Sysmex Corporation, model: FPIA-2000), the value is defined by the following formula and has a value of 1 or less.

Circularity = (perimeter of a circle having the same area as the projected image) / (perimeter of the projected image)
The circularity of about 3000 toner mother particles 12 is calculated as described above, and the average circularity is the average circularity of the toner mother particles 12.

If there are many recesses on the surface of the toner matrix particles 12, the external additive 13 is preferentially fitted into the recesses, and it becomes difficult to obtain the spacer effect of the external additive 13. In particular, when the average circularity of the toner mother particles 12 is more than 0.925, the number of recesses on the surface of the toner mother particles 12 is reduced, so that the spacer effect of the external additive 13 can be obtained. Moreover, the fluidity of the toner 1 is also improved. On the other hand, when the average circularity of the toner mother particles 12 is less than 0.956, the cleaning characteristics can be improved. That is, after the transfer to the recording paper, the toner 1 remaining on the photoconductor drum 121 shown in FIG. 5 can be easily removed by the cleaning unit 126.

Toner 1 can be produced by a pulverization method. More specifically, the method for producing the toner 1 includes a mixing step, a kneading step, a cooling step, a crushing step, a classification step, and an external addition step.

In the mixing step, the amorphous resin, the crystalline resin and, if necessary, other internal additives are mixed to obtain a mixture.

In the kneading step, the mixture is kneaded while being melted using a twin-screw kneader to further uniformly disperse the crystalline resin and other internal additives in the amorphous resin. This gives a kneaded product.

In the cooling step, the kneaded product obtained by melt-kneading is cooled and solidified.

In the crushing step, the solidified product that has been cooled and solidified is crushed by a crusher. Examples of the crusher include a jet crusher that crushes using a supersonic jet stream, and a solidified material in a space formed between a rotor (rotor) and a stator (liner) that rotate at high speed. There is an impact type crusher which introduces and crushes. In the pulverization step, the average circularity of the toner matrix particles 12 can be adjusted by appropriately changing the pulverization conditions. As an example of changing the crushing conditions, the rotation speed of the rotor of the impact type crusher may be changed within the range of 1000 rpm to 10000 rpm.

In the classification step, the particle size of the pulverized product is adjusted. As a result, the toner mother particles 12 are obtained. As the classifier, a known classifier capable of removing the overcrushed toner matrix particles 12 by classification by centrifugal force and classification by wind power can be used. For example, a swivel wind power classifier (rotary wind power classifier) or the like can be used.

In the external addition step, the toner matrix particles 12 and the external additive 13 are mixed by a powder mixer such as a Henshell mixer to attach the external additive 13 to the toner matrix particles 12, and the aggregate of the toner particles 11 is used. A certain toner 1 can be obtained. In the external addition step, the adhesion strength of the external additive 13 to the toner matrix particles 12 can be adjusted by appropriately changing the mixing conditions. As an example of changing the mixing conditions, the rotation speed of the stirring blade of the powder mixer may be changed within the range of 1000 rpm to 1500 rpm.

(2.2) Basic Structure of Carrier The role of the carrier 2 is to agitate and mix with the toner 1 in the developing tank 5 to give the toner 1 a desired charge. On the other hand, the carrier 2 acts as an electrode between the developing unit 124 and the photoconductor drum 121 shown in FIG. 5, and carries the charged toner 1 to the electrostatic latent image on the photoconductor drum 121 to carry the toner image. It is a carrier substance that forms.

The carrier 2 is held on the developing magnet roller of the developing unit 124 by a magnetic force, acts on the developing, then returns to the developing tank 5 again, is stirred and mixed again with the new toner 1, and is repeatedly used for a certain period of time. ..

As shown in FIG. 2, the carrier 2 includes a plurality of carrier particles 21. That is, the carrier 2 is a powder composed of a plurality of carrier particles 21.

Each of the plurality of carrier particles 21 has a carrier core material 22 and a resin layer 23. The resin layer 23 covers the carrier core material 22.

The carrier core material 22 is not particularly limited as long as it is used in the electrophotographic field. Specific examples of the material of the carrier core material 22 include magnetic metals such as iron, copper, nickel and cobalt, and magnetic metal oxides such as ferrite and magnetite.

The volume average particle size of the carrier core material 22 is not particularly limited, but is, for example, in the range of 30 μm or more and 100 μm or less.

The resin layer 23 preferably contains a silicone resin. The silicone resin can suppress the consumption of the toner 1. That is, the so-called toner spend can be suppressed. Further, the adhesion between the carrier core material 22 and the resin layer 23 can be improved.

The resin layer 23 contains a fluororesin 24. Since the fluororesin 24 has a small critical surface tension, it is possible to apply an electrical repulsive force to the external additive 13 to the resin layer 23. Therefore, the external additive 13 desorbed from the toner mother particles 12 is less likely to adhere to the carrier 2, and so-called carrier contamination can be suppressed.

The fluororesin 24 is not particularly limited. Specific examples of the fluororesin 24 include polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), and ethylene / ethylene tetrafluoroethylene copolymer (ETFE).

As described above, from the viewpoint of suppressing carrier contamination, the smaller the critical surface tension of the fluororesin 24 is, the more preferable it is. Specifically, the critical surface tension of the fluororesin 24 is preferably in the range of 17 mN / m or more and 20 mN / m or less. When the critical surface tension is 17 mN / m or more, it is possible to prevent the electrical repulsive force from becoming excessive. When the critical surface tension is 20 mN / m or less, carrier contamination can be further suppressed. In particular, PTFE and PFA are preferable because the critical surface tension is 20 mN / m or less.

The content of the fluororesin 24 with respect to 100 parts by mass of the resin layer 23 is preferably in the range of more than 1 part by mass and less than 20 parts by mass, and more preferably in the range of 3 parts by mass or more and 15 parts by mass or less. .. When the content of the fluororesin 24 is more than 1 part by mass, the charge stability can be improved. When the content of the fluororesin 24 is less than 20 parts by mass, the initial charge amount can be increased.

As a method for producing the carrier 2, a known method can be adopted. For example, a dipping method in which the carrier core material 22 is immersed in a resin liquid for forming the resin layer 23, a spray method in which the resin liquid is sprayed on the carrier core material 22, and a state in which the carrier core material 22 is suspended by fluidized air. Examples include a fluidized bed method in which a resin liquid is sprayed, and a kneader coater method in which a carrier core material 22 and a resin liquid are mixed in a kneader coater to remove a solvent. When fluororesin is used, it should be added to the resin solution in advance.

(2.3) Two-component developer As shown in FIG. 3, the two-component developer 3 contains the above-mentioned toner 1 and the carrier 2. The carrier 2 is preferably as described above, but is not particularly limited.

The two-component developer 3 can be produced by mixing the toner 1 and the carrier 2 using a known mixer. The mass ratio of the toner 1 and the carrier 2 is not particularly limited, but is, for example, 3:97 to 12:88.

(2.4) Toner Cartridge The toner cartridge 4 includes the above-mentioned toner 1 and a container main body 41 for accommodating the toner 1. Since the toner 1 is housed in the container body 41, the toner 1 can be easily handled. The shape of the container body 41 is not particularly limited. The container body 41 preferably has a shape that can be attached to and detached from the image forming apparatus 100. The toner 1 contained in the toner cartridge 4 is supplied into the developing tank 5.

(2.5) Development tank The development tank 5 is housed in the image forming apparatus 100 shown in FIG. The developing tank 5 includes the above-mentioned two-component developer 3 and a tank main body 51 that houses the two-component developer 3. Since it is housed in the tank body 51, the two-component developer 3 can be easily handled. The shape of the tank body 51 is not particularly limited. The tank body 51 preferably has a shape that can be attached to and detached from the image forming apparatus 100.

(2.6) Image Forming Device The overall configuration of the image forming device 100 will be described with reference to FIGS. 4 and 5. The image forming apparatus 100 is an apparatus for forming an image on recording paper or the like by an electrophotographic method, and is a multifunction device in which functions such as a copier (copier), a printer, an image scanner, and a facsimile are integrated into one apparatus (a multifunction device). MFP: MultiFunction Peripheral).

As shown in FIGS. 4 and 5, the image forming apparatus 100 includes an image reading unit 110, an image forming unit 120, a paper feeding unit 130, and an operation panel 70. Further, the image forming apparatus 100 further includes a part of the image reading unit 110, one housing 140 for accommodating the image forming unit 120 and the paper feeding unit 130.

The image reading unit 110 includes a document base 111, an automatic document feeder (ADF: Automatic Document Feeder) 112, and a document image reading unit 113. The platen 111 is made of transparent glass that constitutes the top plate of the housing 140. The automatic document feeder 112 automatically supplies documents onto the platen 111. The document image scanning unit 113 scans and scans an image of a document placed on the document table 111 or a document supplied on the document table 111 by the automatic document feeder 112.

The image forming unit 120 is arranged below the image reading unit 110 and has a plurality of units for performing an electrophotographic process. Here, as shown in FIG. 5, the image forming unit 120 includes a photoconductor drum 121, a charging unit 122, an optical scanning unit 123, a developing unit 124, a transfer unit 125, a cleaning unit 126, and a fixing unit. It has 127 and. The charging unit 122, the optical scanning unit 123, the developing unit 124, the transfer unit 125, and the cleaning unit 126 are arranged in this order around the photoconductor drum 121 so as to be arranged counterclockwise in FIG. Further, the image forming unit 120 is arranged between the cleaning unit 126 and the charging unit 122 around the photoconductor drum 121, and further has a static elimination unit (not shown) for statically eliminating the photoconductor drum 121. There is. Further, the developing unit 124 includes a developing magnet roller 160 and a developing tank 5.

The charging unit 122 charges the photoconductor drum 121 so that the surface of the photoconductor drum 121 has a uniform potential. The optical scanning unit 123 irradiates the surface of the charged photoconductor drum 121 with light (laser light) and scans the surface of the photoconductor drum 121 to form an electrostatic latent image on the surface of the photoconductor drum 121. The developing unit 124 uses the developing magnet roller 160 to attach the charged toner 1 to the electrostatic latent image formed on the surface of the photoconductor drum 121, and visualize the electrostatic latent image to form the toner image. The transfer unit 125 transfers the visualized toner image to the recording paper. The cleaning unit 126 removes the toner 1 remaining on the photoconductor drum 121 so that a new image (toner image) can be formed on the photoconductor drum 121. The static elimination unit eliminates static electricity on the surface of the photoconductor drum 121 after cleaning, and makes the chargeability of the photoconductor drum 121 uniform. The fixing unit 127 fixes (fixes) the toner image transferred to the recording paper by the transfer unit 125 to the recording paper by heat and / or pressure or the like.

The paper feeding unit 130 is arranged below the image forming unit 120, and supplies the recording paper to the image forming unit 120. The paper feed unit 130 includes at least one paper cassette 131, a manual paper feed tray 132, and a registration roller 133. The image forming apparatus 100 takes out one sheet of recording paper from at least one of the paper cassette 131 and the manual paper feed tray 132, and holds the recording paper until the tip of the recording paper is sandwiched between the nip portions of the resist roller 133. Transport. The resist roller 133 records so that the recording paper reaches the transfer unit 125 at a timing when the writing start position of the electrostatic latent image on the photoconductor drum 121 coincides with the transfer start position of the toner image on the recording paper. Transport the paper.

The image forming apparatus 100 described above supplies the recording paper from the paper feeding unit 130 to the image forming unit 120, and delivers the recording paper on which the toner image is fixed to the output tray 150 through the first transport path 151 in the housing 140. Discharge. Further, the image forming apparatus 100 has a second transport path 152 in the housing 140 for switchback transporting the recording paper when printing on the back surface of the recording paper.

The operation panel 70 is a unit for receiving user operations. As shown in FIG. 4, the operation panel 70 projects forward from the front surface of the upper end portion of the housing 140. The operation panel 70 has a tilt function that changes the direction of the operation surface 80 of the operation panel 70 in the vertical direction. That is, the operation panel 70 is held in the housing 140 in a state in which it can swing relative to the housing 140.

(3) Summary As described above, the toner (1) according to the first aspect is the toner (1) containing a plurality of toner particles (11). Each of the plurality of toner particles (11) has a toner mother particle (12) and an external additive (13) attached to the toner mother particle (12). The toner mother particles (12) include an amorphous resin (16) and a crystalline resin (17). The adhesion strength of the external additive (13) to the toner matrix particles (12) is less than 75%.

According to this configuration, the external additive (13) is less likely to be embedded in the toner mother particles (12), a spacer effect can be obtained, and the generation of a developing memory can be suppressed.

In the toner (1) according to the second aspect, in the first aspect, the external additive (13) is the first average particle as compared with the first external additive (14) and the first external additive (14). It contains a second external additive (15) having a small diameter.

According to this configuration, the spacer effect can be obtained by the first external additive (14), and the fluidity of the toner (1) and the dispersion of the external additive (13) are obtained by the second external additive (15). It is possible to improve the sex.

In the toner (1) according to the third aspect, in the second aspect, the primary average particle size of the first external additive (14) is in the range of 30 nm or more and less than 200 nm.

According to this configuration, the spacer effect can be easily obtained, and the charge amount stability can be ensured.

In the toner (1) according to the fourth aspect, in the second or third aspect, the primary average particle size of the second external additive (15) is less than 30 nm.

According to this configuration, the charge amount stability can be improved.

In the toner (1) according to the fifth aspect, in any one of the first to fourth aspects, the average circularity of the toner matrix particles (12) is in the range of more than 0.925 and less than 0.956.

According to this configuration, the spacer effect of the external additive (13) can be obtained, and the fluidity of the toner (1) is also improved. Further, the cleaning characteristics can be improved.

In the toner (1) according to the sixth aspect, in any one of the first to fifth aspects, the amorphous resin (16) contains an amorphous polyester resin. The crystalline resin (17) contains a crystalline polyester resin.

According to this configuration, the crystalline polyester resin makes it possible to achieve both low-temperature fixability and storage stability of the toner (1).

In the toner (1) according to the seventh aspect, in any one of the first to sixth aspects, the external additive (13) is silica.

According to this configuration, it is possible to suppress the generation of developing memory as compared with the case of using other ones.

The two-component developer (3) according to the eighth aspect contains the toner (1) according to any one of the first to seventh aspects and the carrier (2).

According to this configuration, it is possible to suppress the generation of development memory.

In the two-component developer (3) according to the ninth aspect, in the eighth aspect, the carrier (2) includes a plurality of carrier particles (21). Each of the plurality of carrier particles (21) has a carrier core material (22) and a resin layer (23) that coats the carrier core material (22). The resin layer (23) contains a fluororesin (24).

According to this configuration, carrier contamination can be suppressed.

In the two-component developer (3) according to the tenth aspect, in the ninth aspect, the critical surface tension of the fluororesin (24) is in the range of 17 mN / m or more and 20 mN / m or less.

According to this configuration, it is possible to suppress an excessive electric repulsive force, and further suppress carrier contamination.

In the two-component developer (3) according to the eleventh aspect, in the ninth or tenth aspect, the content of the fluororesin (24) is more than 1 part by mass and 20% by mass with respect to 100 parts by mass of the resin layer (23). It is within the range of less than a part.

According to this configuration, the stability of the charge amount can be improved, and the initial charge amount can be further increased.

In the two-component developer (3) according to the twelfth aspect, in any one of the ninth to eleventh aspects, the resin layer (23) contains a silicone resin.

According to this configuration, the toner spend can be suppressed. Further, the adhesion between the carrier core material (22) and the resin layer (23) can be improved.

The toner cartridge (4) according to the thirteenth aspect includes a toner (1) according to any one of the first to seventh aspects and a container body (41) for accommodating the toner (1).

According to this configuration, the handling of the toner (1) becomes easy.

The developing tank (5) according to the fourteenth aspect is the developing tank (5) housed in the image forming apparatus (100). The developing tank (5) includes a two-component developing agent (3) according to any one of the eighth to twelfth aspects, and a tank main body (51) containing the two-component developing agent (3).

According to this configuration, the handling of the two-component developer (3) becomes easy.

Hereinafter, one aspect of the present disclosure will be specifically described with reference to Examples, but the present disclosure is not limited to the Examples.

(Examples 1 to 5 and Comparative Example 1)
[Manufacturing of toner]
The following toner raw materials were used.
Amorphous polyester resin (100 parts by mass)
-Crystalline polyester resin (10.0 parts by mass)
-Cyan pigment (copper phthalocyanine blue) (5.0 parts by mass)
-Charge control agent (manufactured by Japan Carlit Co., Ltd., product name: LR-147) (1.0 part by mass)
-Wax (manufactured by NOF CORPORATION, product name: WEP-8) (5.0 parts by mass)
The toner raw material is stirred and mixed with a Henshell mixer (manufactured by Nippon Coke Industries Co., Ltd., model: FM20C) for 5 minutes, and then the obtained stirring mixture is mixed with an open roll type continuous kneader (manufactured by Nippon Coke Industries Co., Ltd., model: MOS320). -1800) was melt-kneaded.

The obtained melt-kneaded product is cooled by a cooling belt and then roughly crushed using a speed mill having a φ2 mm screen, and then a jet crusher (manufactured by Nittetsu Mining Co., Ltd., model: IDS-2,). ), And further pulverized using an elbow jet classifier (manufactured by Nittetsu Mining Co., Ltd., model: EJ-LABO) to obtain a toner having a volume average particle diameter of 6.7 μm and an average circularity of 0.940. A mother particle was obtained.

Next, 1.0 part by mass of the first external additive (manufactured by Cabot Co., Ltd., trade name: TG-C190, primary average particle diameter 115 nm) was added to 100 parts by mass of the obtained toner mother particles. 2 Add 1.5 parts by mass of an external additive (manufactured by Aerosil, trade name: R974, primary average particle size 12 nm) and stir with an air flow mixer (manufactured by Nippon Coke Industries Co., Ltd., Henschel mixer) to increase the volume. A toner having an average particle size of 6.7 μm was produced. The toners of Examples 1 to 5 and Comparative Example 1 were produced by appropriately changing the tip speed and stirring time of the stirring blades. In the toners of Examples 1 to 5 and Comparative Example 1, the toner mother particles are common.

For each of the obtained toners, the adhesive strength of the external additive was measured by the following procedure.
(1) Add 2.0 g of toner to 40 ml of a 0.2 mass% aqueous solution of triton (polyoxyethylene octylphenyl ether) and stir for 1 minute.
(2) Further, the above aqueous solution is irradiated with ultrasonic waves with a homogenizer: US-300T (manufactured by Nissei Tokyo Office Co., Ltd.) (output: 40 μA, 4 minutes).
(3) The aqueous solution after ultrasonic irradiation is left to stand for 3 hours to separate the toner and the released external additive.
(4) After removing the supernatant, add about 50 ml of pure water to the precipitate and stir for 5 minutes.
(5) Suction filtration is performed using a membrane filter (manufactured by Advantech) having a pore size of 1 μm.
(6) The toner remaining on the filter is vacuum dried overnight.
(7) Strength of element (Si) in 1 g of toner before and after the series of treatments (1) to (6) above with a fluorescent X-ray analyzer (manufactured by Rigaku Co., Ltd., model: ZSX Primus II) Is analyzed, and the adhesion strength of the external additive is calculated by the following formula.

Adhesive strength of external additive (%) = {(Si strength after treatment) / (Si strength before treatment)} x 100
[Manufacturing of carriers]
Next, 100 parts by weight of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KR-251), PTFE (manufactured by Daikin Kogyo Co., Ltd., trade name: LDE-410, critical surface tension 18.5 mN) as fluororesin fine particles / M) Is added in an amount of 10 parts by mass to prepare a resin solution, and a carrier core material (manufactured by DOWA IP Creation Co., Ltd.) is immersed in this resin solution to produce carriers of Examples 1 to 4 and Comparative Example 1. bottom. The fluororesin fine particles are common to the carriers of Examples 1 to 4 and Comparative Example 1. Example 5 is the same as Examples 1 to 4 and Comparative Example 1 except that fluororesin particles are not used.

[Manufacturing of two-component developer]
The two-component developer of Examples 1 to 5 and Comparative Example 1 was produced by mixing the toner and the carrier obtained as described above in a mass ratio of 8:92.

(Evaluation of live-action characteristics)
The developing memory, charge stability and filming were evaluated for Examples 1-5 and Comparative Example 1.

[Development memory]
The two-component developer was filled in the developing tank of a multifunction device (manufactured by Sharp Corporation, model: MX-6150FN), and 10,000 sheets of originals having a printing rate of 1% were printed.

Next, an A3 size development memory confirmation chart 9 as shown in FIG. 6 was printed. The development memory confirmation chart 9 has a solid circular image 91 at the tip of the paper passing direction X, and a halftone image 92 behind the solid circular image 91. The circular image 91 occupies the region of one cycle T of the developing magnet roller (roller diameter: 18 mm) along the paper passing direction X. Eight circular images 91 are arranged in a direction perpendicular to the paper passing direction X. Then, by printing the development memory confirmation chart 9, it is confirmed how many circular images 91 are repeated as the ghost image 93 on the halftone image 92 along the paper passing direction X. FIG. 6 shows an example in which three ghost images 93 are slightly repeated along the paper passing direction X.
The evaluation criteria are as follows.
◎: No repetition 〇: 1 time △: 2 times ×: 3 times or more.

[Charge stability]
The two-component developer was filled in the developing tank of a multifunction device (manufactured by Sharp Corporation, model: MX-6150FN), and the two-component developer was sampled when the READY state was reached (before the first image was drawn). Next, after printing 10,000 sheets of a document having a printing rate of 1%, the two-component developer was sampled again. For the two-component developer before and after printing, the charge amount of the toner was measured using a charge amount measuring device (manufactured by TREK JAPAN, model: Model 210HS-2A).

Specifically, first, 0.2 g of the two-component developer is taken, placed on a table, and covered with a stainless mesh (# 795). Next, a suction nozzle is placed on the mesh to suck the toner. After that, the amount of charge of the sucked toner is displayed, so the amount of charge per 1 g of toner (Q / m) is calculated by dividing by the amount of sucked toner. Then, the charge reduction rate is calculated from the initial charge amount before drawing and the charge amount after printing 10,000 sheets by the following formula.

Charge reduction rate (%) = {1- (charge amount after printing 10000 sheets) / (initial charge amount)} x 100
The evaluation criteria are as follows.
⊚: 10% or less ○: More than 10% 20% or less Δ: More than 20% 30% or less ×: More than 30%.

[Filming]
After printing 100,000 sheets, it was visually observed whether or not the external additive was attached to the surface of the photoconductor drum.
The evaluation criteria are as follows.
○: None ×: Yes.

Comparing Examples 1 to 5 with Comparative Example 1, it was confirmed that the generation of developing memory can be suppressed for the toner if the adhesion strength of the external additive is less than 75%. Furthermore, it was found that the adhesion strength of the external additive is preferably more than 36% in that filming is suppressed.

(Examples 6 to 11)
Next, the toners of Examples 6 to 11 were produced in substantially the same manner as the toners of Example 3. However, the toners of Examples 6 to 11 differ in the primary average particle size of the first external additive and the second external additive in the toner of Example 3. Table 3 shows the manufacturers and trade names of the external additives used in the production of the toners of Examples 6 to 11. The carriers of Examples 6 to 11 are the same as the carriers of Example 3. The two-component developing agents of Examples 6 to 11 were produced so that the mass ratio of the toner and the carrier was the same as that of Example 3.

The developing memory and charge stability were evaluated for Examples 6 to 11. The results are shown in Table 2.

Looking at Examples 3 and 6 to 9, it was confirmed that when the primary average particle size of the second external additive is constant, the larger the primary average particle size of the first external additive, the more the generation of the developing memory can be suppressed. Was done. On the other hand, it was found that the primary average particle size of the first external additive is preferably less than 200 nm in order to ensure the stability of the amount of charge.

Next, looking at Examples 3, 10 and 11, when the primary average particle size of the first external additive is constant, the charge amount stability is improved, and the primary average particle size of the second external additive is , Preferably less than 30 nm.

(Examples 12 to 18)
Next, the carriers of Examples 12 to 18 were manufactured in substantially the same manner as the carriers of Example 3. However, the carriers of Examples 12 to 18 differ in the type and content of the fluororesin of Example 3.
In Example 12, PFA (critical surface tension 17.8 mN / m) was used as the fluororesin particles, and in Example 13, ETFE (critical surface tension 22.1 mN / m) was used as the fluororesin particles. The toners of Examples 12 to 18 are the same as the toners of Example 3. The two-component developing agents of Examples 12 to 18 were produced so that the mass ratio of the toner and the carrier was the same as that of Example 3.

For Examples 12-18, the developing memory, charge stability and initial charge were evaluated. The results are shown in Table 4.

Looking at Examples 3, 12 and 13, it was found that among PTFE, PFA and ETFE, PTFE and PFA are preferable from the viewpoint of charge stability when the content of the fluororesin is constant. For ETFE, a slight decrease in the amount of charge was observed. It is considered that this is because ETFE has a relatively high critical surface tension among the fluororesins, and thus the effect of suppressing the adhesion of the external additive is weakened.

Next, looking at Examples 3, 14 to 18, when PTFE is used as the fluororesin, the content thereof is preferably more than 1 part by mass from the viewpoint of charge stability, and from the viewpoint of the initial charge. It was found that it was preferably less than 20 parts by mass.

(Examples 19 to 22)
Next, the toners of Examples 19 to 22 were produced in substantially the same manner as the toners of Example 3. However, the toners of Examples 19 to 22 differ in the average circularity of the toner matrix particles in the toner of Example 3. In producing the toner matrix particles of Examples 19 to 22, the pulverization conditions in the pulverization step when producing the toner matrix particles of Example 3 were appropriately changed. The carriers of Examples 19 to 22 are the same as the carriers of Example 3. The two-component developer of Examples 19 to 22 was produced so that the mass ratio of the toner and the carrier was the same as that of Example 3.

The developing memory was evaluated for Examples 19-22. The results are shown in Table 5.

Further, the cleaning characteristics of Examples 3 and 19 to 22 were evaluated. The results are shown in Table 5.

[Cleaning characteristics]
It was visually observed whether or not the toner remaining on the photoconductor drum after the transfer to the recording paper was removed by the cleaning unit.

The evaluation criteria are as follows.
◯: No toner residue ×: Toner residue.

Comparing Examples 3, 19, 21 and 22 with Example 20, it was confirmed that when the average circularity of the toner mother particles exceeds 0.925, the generation of the developing memory can be further suppressed.

On the other hand, comparing Examples 3 and 19 to 21 with Example 22, it was confirmed that the cleaning characteristics were improved when the average circularity of the toner mother particles was less than 0.956.

From the above, it was found that the average circularity of the toner matrix particles is preferably more than 0.925 and less than 0.956.

1 Toner 2 Carrier 3 Two-component developer 4 Toner cartridge 5 Development tank 11 Toner particles 12 Toner mother particles 13 External agent 14 First external agent 15 Second external agent 16 Amorphous resin 17 Crystalline resin 21 Carrier particles 22 Carrier core material 23 Resin layer 24 Fluororesin 41 Container body 51 Tank body

Claims (10)

It contains a toner containing a plurality of toner particles and a carrier,
Each of the plurality of toner particles has a toner mother particle and an external additive adhering to the toner mother particle.
The toner mother particles contain an amorphous resin and a crystalline resin.
The adhesive strength of the external additive to the toner matrix particles is 36% or more and less than 75%.
The carrier contains a plurality of carrier particles and contains a plurality of carrier particles.
Each of the plurality of carrier particles has a carrier core material and a resin layer that coats the carrier core material.
The resin layer contains a fluororesin and contains
The critical surface tension of the fluororesin is in the range of 17 mN / m or more and 20 mN / m or less.
Two-component developer . It contains a toner containing a plurality of toner particles and a carrier,
Each of the plurality of toner particles has a toner mother particle and an external additive adhering to the toner mother particle.
The toner mother particles contain an amorphous resin and a crystalline resin.
The adhesive strength of the external additive to the toner matrix particles is 36% or more and less than 75%.
The carrier contains a plurality of carrier particles and contains a plurality of carrier particles.
Each of the plurality of carrier particles has a carrier core material and a resin layer that coats the carrier core material.
The resin layer contains a fluororesin and contains
The content of the fluororesin with respect to 100 parts by mass of the resin layer is in the range of more than 1 part by mass and less than 20 parts by mass.
Two-component developer . It contains a toner containing a plurality of toner particles and a carrier,
Each of the plurality of toner particles has a toner mother particle and an external additive adhering to the toner mother particle.
The toner mother particles contain an amorphous resin and a crystalline resin.
The adhesive strength of the external additive to the toner matrix particles is 36% or more and less than 75%.
The carrier contains a plurality of carrier particles and contains a plurality of carrier particles.
Each of the plurality of carrier particles has a carrier core material and a resin layer that coats the carrier core material.
The resin layer contains a fluororesin and a silicone resin.
Two-component developer . The external additive includes a first external additive and a second external additive having a smaller primary average particle size than the first external additive.
The two-component developer according to any one of claims 1 to 3 . The primary average particle size of the first external additive is in the range of 30 nm or more and less than 200 nm.
The two-component developer according to claim 4 . The primary average particle size of the second external additive is less than 30 nm.
The two-component developer according to claim 4 or 5 . The average circularity of the toner matrix particles is in the range of more than 0.925 and less than 0.956.
The two-component developer according to any one of claims 1 to 6 . The amorphous resin contains an amorphous polyester resin, and the amorphous resin contains an amorphous polyester resin.
The crystalline resin contains a crystalline polyester resin.
The two-component developer according to any one of claims 1 to 7 . The external additive is silica
The two-component developer according to any one of claims 1 to 8 . A developing tank housed in an image forming apparatus
A developing tank including the two-component developer according to any one of claims 1 to 9 and a tank body containing the two-component developer.

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