JP4301054B2 - Non-magnetic one-component toner - Google Patents

Description

  The present invention relates to a toner used in a developing device for image formation by an electrophotographic method, and in particular, has excellent chargeability and fluidity, no fusing and filming, and excellent image quality capable of supporting high speed. The present invention relates to a non-magnetic one-component toner.

  Electrophotographic image formation is generally obtained by developing and visualizing and developing toner by supplying toner to the electrostatic latent image formed on the surface of the electrostatic latent image carrier using a developing roller. This is done by transferring and fixing the toner image on a sheet.

In recent years, a non-magnetic one-component developing method using a non-magnetic one-component toner has been widely used as a developing method because of demands for high-speed printing, high image quality, colorization, and simple apparatus configuration.
In this non-magnetic one-component developing system, an elastic developing roller having at least a surface of a semiconductive elastic material such as urethane rubber is used as a developing roller for carrying and transporting non-magnetic one-component toner. A blade is provided as a toner layer regulating member for charging the toner while regulating the thickness of the toner so as to form the non-magnetic one-component toner in a thin layer on the roller. The elastic developing roller is used by being driven at a toner conveying speed of 100 mm / second or more in accordance with, for example, an increase in speed.

  Such a non-magnetic one-component toner used for image formation is usually produced by pulverizing and classifying a composition obtained by kneading a binder resin and a colorant.

As the binder resin, styrene / acrylic resin, polyester resin, epoxy resin, etc. are used. However, due to the recent colorization of printed matter, color development and transparency when printing on OHP paper and low temperature fixability are used. The demand for excellent toner has increased, and various binder resins having a molecular weight distribution suitable for them have been studied.
Among the above binder resins, the polyester resin is highly durable even when the molecular weight is lowered in order to satisfy the transparency, and since it has a carboxyl group at the end of the resin, the pigment dispersibility is also good. It tends to be frequently used for image formation.

By the way, the problems to be solved increase with the improvement in image quality and the speed, and the toner itself has been required to have various characteristics corresponding to it.
For example, in high speed printing, the density at the trailing edge of printing tends to decrease during high density printing. This is thought to be based on changes in chargeability and fluidity due to speeding up.

In the case of the non-magnetic one-component development method in which friction with the blade contributes to charging of the toner as described above, the stress between the toner and the blade is strong, and the toner is fused to the blade, or the electrostatic latent image carrier In other words, so-called filming occurs on the surface of the photoconductive drum, and image quality is deteriorated.
Therefore, in general, the toner is charged with a charge control agent or waxes for controlling the charge amount or preventing offset, and for the purpose of preventing blocking or improving fluidity, hydrophobic silica or alumina is used after classification. Toner characteristics are adjusted by adding inorganic fine particles.

  For example, Patent Document 1 discloses that toner particles containing a colorant and a binder resin and silicone oil adhering to the surface of the toner particles have excellent chargeability and fluidity and improve solid followability and fog. Silica, which is a first inorganic oxide (first external additive) having an average particle diameter of 5 to 20 nm, an acrylic polymer powder or a silicone resin having an average particle diameter of 0.1 to 1.0 μm, an average particle diameter of 0 It is described that a specific external additive composed of an inorganic oxide (second external additive) of any one of 1 to 3.0 μm ferroelectric powder and silica having an average particle diameter of 10 to 50 nm is described. .

  For the problem of toner fusion to the blade and filming on the surface of the photosensitive drum, alumina powder having an average particle size of 0.1 to 1.0 μm is added as an inorganic oxide having excellent polishing performance. It is known to do. (For example, see Patent Document 2.)

  Furthermore, in order to provide a toner that is excellent in solid followability and does not reverse transfer, as an external additive, silica having an average particle diameter of less than 20 nm, silica having an average particle diameter of 20 nm or more, and an average particle diameter of 1 μm or more are preferable. Also known is an invention containing three types of inorganic fine particles made of 1 to 3 μm alumina. (For example, refer to Patent Document 3.)

On the other hand, it is known to regulate the amount of water in the toner in order to improve fixability and developability. (For example, see Patent Documents 4 and 5.)
Further, in the toner comprising the colorant-containing resin particles and the fluidity-imparting agent, the saturation moisture content in the environment of the fluidity-imparting agent at a temperature of 23 ° C. and a humidity of 60% RH is 0.2 to 12.0% by weight. By doing so, it is known that the charge amount can be controlled to a desirable value. (For example, see Patent Document 6.)
JP-A-8-101525 ([Summary]) JP 2000-250251 A ([Summary]) JP 2002-296830 A ([Summary]) JP-A 61-284771 JP 7-248647 A ([Summary], paragraphs 0020 to 0023) Japanese Patent Laid-Open No. 3-116053

However, when using an external additive such as silica as described above to improve the fluidity of the toner, it is also known that when it is added in a large amount, a so-called “fogging” is caused. It is necessary to set the blending ratio to an appropriate state.
In addition, it is important that the external additive as an abrasive is basically free from the toner base, and when it is embedded in the toner, the amount of charge of the toner tends to fluctuate and fog tends to increase. Sexual effects are also reduced.

  Therefore, in the case of an abrasive inorganic oxide such as alumina, a relatively large particle size of about 1.0 μm is used, but such an inorganic oxide is not embedded in the toner. Because it exists in a free state, the toner and the inorganic oxide are biased in printing over a long period of time, resulting in the inorganic oxide being transferred or concentrating. A new bug that can no longer function is found.

  On the other hand, none of the above-mentioned Patent Documents 1 to 3 has solved such a problem, and in particular, the suppression of fog is insufficient. Although it is desirable to control the water content of the toner as in Patent Documents 4 to 6, it is difficult to control the chargeability sufficiently by simply specifying the water content of the toner.

  The present invention has been made under such circumstances, and can cope with a high-speed non-magnetic one-component developing device in which the toner conveying speed on the surface of the developing roller for carrying and conveying the toner is 100 mm / second or more, An object of the present invention is to provide a non-magnetic one-component toner having good chargeability and fluidity and no fusing or filming.

  In order to solve the above problems, the non-magnetic one-component toner of the present invention has an elastic developing roller for carrying and transporting the toner, and the thickness of the toner so that the toner is formed in a thin layer on the elastic developing roller. A toner layer regulating member for regulating, assuming that it is used in a developing device having a toner conveying speed of 100 mm / second or more on the surface of the elastic developing roller, at least a mixture of a binder resin and a colorant, Externally added hydrophobized silica particles as the first inorganic fine particles and second inorganic fine particles having an average particle size of 0.5 to 5.0 μm, the toner water content (%) is a, the aggregation degree ( %), Where b ≦ 0.5 ≦ a ≦ 1.5 and 5 ≦ b ≦ 15.

  In the nonmagnetic one-component toner of the present invention, alumina is preferably used as the second inorganic fine particles. The binder resin is preferably a polyester resin.

  The toner according to the present invention may be internally added with a known charge control agent. Examples of the charge control agent include a quaternary ammonium salt and a salt-forming compound thereof for obtaining a positively chargeable toner, and a metal complex or metal complex of salicylic acid or alkylsalicylic acid for obtaining a negatively chargeable toner. Boron-containing potassium salt compounds and the like are preferable.

  As a method for producing the nonmagnetic one-component toner of the present invention, the following general production method can be employed. First, a resin, a colorant, and, if necessary, a charge control agent, wax, and the like are uniformly mixed by a Henschel mixer or the like. Next, this mixture is melt-kneaded using a kneader, an extruder, a roll mill or the like.

  Next, the kneaded material is coarsely pulverized using a hammer mill, a cutter mill or the like, and then finely pulverized using a jet mill, a single mill or the like. Thereafter, the finely pulverized product is classified by a DS (dispersion classifier), a zigzag classifier or the like. The average particle size of the toner obtained by classification is preferably 3 to 18 μm.

  To the classified toner particles, second inorganic fine particles such as silica and alumina hydrophobized as external additives are added and mixed uniformly by a Henschel mixer or the like to produce a toner.

  According to the present invention, at least a mixture of a binder resin and a colorant is provided with hydrophobic silica particles as first inorganic fine particles and second inorganic fine particles having a particle size of 0.5 to 5.0 μm. A developing roller for carrying and transporting the toner by setting the toner water content (%) in the range of 0.5 to 1.5 and the aggregation degree (%) in the range of 5 to 15 Even in an image forming apparatus equipped with a developing device having a toner transport speed of 100 mm / second or more on the surface, the toner chargeability is stabilized and the fluidity is improved, so that toner followability, blade fusion, and on-drum fill Can be solved.

(Embodiment)
Hereinafter, embodiments of the present invention will be shown to describe the present invention more specifically. FIG. 1 schematically shows an internal configuration of a color image forming apparatus (printer apparatus) suitable for image formation using toner manufactured according to the present invention. First, the overall configuration of the color image forming apparatus according to the present invention will be described with reference to FIG.

  The internal configuration of the printer apparatus 1 shown in FIG. 1 includes an image forming unit 2, a duplex printing conveyance unit 3, a paper feeding unit 4, and the like. Here, the image forming unit 2 has a configuration in which four image forming units 5 to 8 are arranged side by side, and magenta (M), cyan (C), and yellow (Y) from the right side to the left side of the drawing. And black (K) in this order. Here, the magenta (M), cyan (C), and yellow (Y) image forming units 5 to 7 are configured to perform color printing by subtractive color mixing, and the black (K) image forming unit 8 is configured to perform monochrome printing. This is a configuration that can be used alone.

  Each of the image forming units 5 to 8 is composed of a drum unit DU and a toner unit (developing device) TU, and has the same configuration except for the toner contained in the developing hopper of the toner unit TU. The toner units TU of the image forming units 5 to 8 respectively store M (magenta), C (cyan), Y (yellow), and black (K) color toners (non-magnetic one-component toner). Each color toner is a toner that is manufactured by the method of the present invention and has excellent followability, blade fusing property, and on-drum filming property.

  Therefore, the configuration will be described by taking the image forming unit 8 including the developing device of the present invention as an example. The drum unit DU accommodates a photosensitive drum 9, a charger 10a, a cleaner 10e, and the like, and a print head 10b is disposed above the drum unit DU. The toner unit TU is configured such that a developing roller 10c and toner manufactured by the method of the present invention are accommodated in the developing device 44.

  The peripheral surface of the photosensitive drum 9 is made of, for example, an organic photoconductive material. In the vicinity of the peripheral surface of the photosensitive drum 9, a charger 10a, a print head 10b, a developing roller 10c, a transfer device 10d, and a cleaner 10e are provided. They are arranged sequentially. The photosensitive drum 9 is rotated in the direction of the arrow, and first, the peripheral surface of the photosensitive drum 9 is uniformly charged by applying a charge from the charger 10a. Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 9 by optical writing based on print information from the print head 10b, and a toner image is formed by development processing by the developing roller 10c. In this way, the toner image formed on the peripheral surface of the photosensitive drum 9 reaches the position of the transfer unit 10d as the photosensitive drum 9 rotates in the direction of the arrow, and directly below the photosensitive drum 9 in the direction of the arrow. The image is transferred to the moving paper.

  On the other hand, the paper is transported by the paper feed cassette 11, the standby roller pair 12, the transport belt 13, the drive roller 14 and the like constituting the paper feed unit 4, and the paper feed cassette 11a is rotated by the rotation of the paper feed roller 11a. The sheet transported from 11 is sent to the standby roller pair 12 and further sent onto the transport belt 13 at a timing coincident with the toner image and reaches each transfer device 10d. Then, the toner image is transferred in each transfer device 10d, and the sheet on which the toner image is transferred moves on the conveyance belt 13 in the direction of the arrow according to the movement of the conveyance belt 13, and a heat fixing process is performed in the fixing unit 15. .

  The above-mentioned paper includes not only the paper carried out from the paper feed cassette 11 but also the paper supplied from the MPF tray 16. In this case, the paper is carried in by the paper feed roller 16a, Printing processing is performed.

  The fixing unit 15 includes a heat roller 15a, a press roller 15b, an oil application roller 15c, and the like. The sheet is transferred to the sheet while the sheet is nipped and conveyed between the heat roller 15a and the press roller 15b. For example, a plurality of color toner images are melted and thermally fixed on a sheet. The oil application roller 15c has a function of applying releasable oil to the peripheral surface of the heat roller 15a and removing toner remaining on the heat roller 15a.

  The paper on which the toner image is fixed by the fixing unit 15 is conveyed upward or leftward on the paper surface via the switching flap 17. The switching flap 17 is normally located at a broken line position, and the sheet is guided to the sheet discharge unit 21 via the sheet discharge roller pair 20.

  On the other hand, the transport unit 3 for double-sided printing is configured to be detachable from the apparatus main body, and is a unit to be mounted when performing double-sided printing with the printer device 1 of this example, and includes a plurality of reverse transport roller pairs 18a to 18a. 18e is disposed. In the case of duplex printing, the sheet is once sent upward by the switching flap 17, and when the trailing edge of the sheet reaches the conveying roller pair 19, for example, the conveyance of the sheet is stopped and the sheet is further conveyed in the reverse direction. . By this control, the sheet is carried into the sheet conveyance path of the duplex printing conveyance unit 3 at the lower position, and the sheet is fed in the reverse direction by the reverse conveyance roller pair 18a to 18e, and reaches the standby roller pair 12 again, as described above. Then, the toner image is sent to the transfer unit at a timing coincident with the toner image, and the toner image is transferred to the back surface of the paper.

  FIG. 2 is an external perspective view of the printer apparatus 1 shown in FIG. The printer apparatus 1 shown in FIG. 1 includes an apparatus main body upper part 22 and an apparatus main body lower part 23, and an operation panel 33 is disposed on the apparatus main body upper part 22, and a printing paper discharge unit 21 is formed on the upper surface. Has been. The operation panel 33 includes a key operation unit 33a provided with a plurality of keys, and a display unit 33b such as a liquid crystal display that performs display based on display information output from a CPU 30 in FIG. Further, the printing paper created by each image forming unit is output to the paper discharge unit 21 by the rotation of the paper discharge roller pair 20 and is sequentially stacked on the paper discharge unit 21.

  The apparatus main body lower portion 23 is provided with a front cover 24 that can be opened and closed on the front surface thereof. The front cover 24 is opened, for example, during jam processing or maintenance.

  FIG. 3 is a circuit block diagram of the printer apparatus 1 having the above configuration. In FIG. 3, the circuit block includes an interface controller (hereinafter referred to as I / F controller) 26, a printer controller 28, a printer printing unit 29, a CPU 30, a ROM 31, an operation panel 33, and an EEPROM 32. The I / F controller 26 converts print data supplied from the host device into bitmap data and develops it in the frame memory 27. In the frame memory 27, a storage area is set for each of magenta (M), cyan (C), yellow (Y), and black (K), and data of each color is developed in the corresponding area.

  The data expanded in the frame memory 27 is output to the printer controller 28 and output to the printer printing unit 29 under the control of the CPU 30. At this time, data of each color of magenta (M), cyan (C), yellow (Y), and black (K) is supplied to the corresponding print head 10b in FIG.

  The ROM 31 stores the system program of this example, and the CPU 30 performs processing according to this system program.

  Next, the basic operation of the printer apparatus 1 described above will be described. First, when the power is turned on and the quality of the paper to be used, the number of sheets, the print mode, and other designations are input as a key input or a signal from a host device to be connected, the paper feed roller 11a is set to one by a drive mechanism not shown. The sheet rotates and feeds the sheet placed and accommodated in the sheet feeding cassette 11 in the direction of the standby roll pair 12. The standby roll pair 12 temporarily stops the rotation, and waits for the conveyance timing in a state where the leading end of the sheet is brought into contact with the holding portion formed by the pair of rollers.

  Subsequently, the drive roller 14 rotates counterclockwise, and the driven roller 14 'is driven to rotate in the same counterclockwise direction. As a result, the transport belt 13 is circulated and moved counterclockwise as a whole, with the upper circulating portion abutting against the four photosensitive drums 9.

  At the same time, each drum unit DU and toner unit TU are sequentially driven in accordance with the printing timing. The photosensitive drum 9 rotates in the clockwise direction, the charger 10a applies a uniform high negative charge to the circumferential surface of the photosensitive drum 9, and the print head 10b generates an image signal on the circumferential surface of the photosensitive drum 9. Accordingly, exposure is performed to form a low potential portion.

  As a result, an electrostatic latent image composed of a high negative potential portion by the charger 10a and a low negative potential portion by exposure is formed. The developing roller 10c of the developing device 44 transfers toner to the low potential portion of the electrostatic latent image to form a toner image on the circumferential surface of the photosensitive drum 9 (reverse development).

  When the leading edge of the toner image on the peripheral surface of the most upstream photosensitive drum 9 is rotated and conveyed to a point facing the conveying belt 13, the standby is performed so that the print start position of the sheet coincides with the opposite point. The roller pair 12 starts to rotate and feeds the paper to the paper carry-in section. The sheet is attracted to the conveyance belt 13 and conveyed to the first transfer unit formed by the photosensitive drum 9 and the transfer device 10d.

  The transfer device 10 d applies a transfer current output from the transfer bias power source to the sheet via the conveyance belt 13. The M (magenta) toner image on the photosensitive drum 9 is transferred onto the sheet by the transfer current applied from the transfer device. Subsequently, the C (cyan) toner image is transferred at the second transfer portion from the upstream, and the Y (yellow) toner image is transferred at the third transfer portion from the upstream. Then, the K (black) toner image is sequentially transferred at the fourth (ie, the most downstream) transfer portion from the upstream.

  In this way, the sheet onto which the four color toner images have been transferred is separated from the conveying belt 13 and carried into the fixing unit 15. The fixing unit 15 heat-fixes the toner image on the paper. After this image fixing, the paper is discharged onto the upper paper discharge unit 21 with the toner image facing down, for example, by a pair of paper discharge rollers 20.

  The printer apparatus 1 according to the present invention includes a full-color mode in which four image forming units are operated to form a full-color image, and a monochrome mode in which only one image forming unit is operated. The full color mode can also be configured by operating the three image forming units M (magenta), C (cyan), and Y (yellow).

  In the printer apparatus 1 operating as described above, each developing device 44 is configured as follows in order to form a stable toner image on the photosensitive drum 9.

  FIG. 4 is a side sectional view schematically showing the main part of the developing device 44 of the present invention. The developing device 44 shown in the figure is detachable from the printer device 1 and is a toner unit TU that constitutes one image forming unit 8 together with the drum unit DU. The developing device 44 includes a hopper 61, and a developing roller 10 c made of a conductive rubber roller is rotatably held in a lower opening of the hopper 61. The toner 62 is accommodated in the hopper 61 and embedded in the toner 62. And a stirring member 63 that stirs the toner.

  In addition, a supply roller 64 made of a sponge body is disposed in pressure contact with the developing roller 10c at the lowermost portion of the developing device 44. The developing roller 10c is provided with a metal leaf spring doctor blade 65 in pressure contact with the oblique upper right peripheral surface thereof, and a squeeze sheet (conductive regulation sheet) 66 in contact with the lower peripheral surface. Yes. The squeeze sheet 66 is provided with conductive regulation sheet bias means including a bias power supply 71. Sealing members 67 are provided on both sides of the doctor blade 65 to isolate the inside and outside of the opening of the hopper 61 and prevent leakage of the toner 62.

  By the way, the toner 62 in the non-development portion remaining on the peripheral surface of the developing roller 10c after the development on the photosensitive drum 9 is scraped off in the developing device to eliminate the developing memory. The rubbing force of the supply roller 64 varies depending on the adhesion force of the toner 62 to the developing roller 10c. That is, a strong rubbing force is required for a toner having a strong adhesive force, but a low rubbing force is sufficient for a toner having a weak adhesive force. It can be said that the adhesion force of the toner 62 to the developing roller 10 c is substantially determined by the charging ability of the toner 62. That is, the smaller the triboelectric charge amount, the weaker the adhesive force, and therefore it is easier to scrape off from the developing roller 10c.

  However, the triboelectric charge amount of the toner 62 is closely related to the adhesion development (so-called photoconductor fogging) to the non-image portion which occurs at the time of development and becomes a problem. Easy to generate. Therefore, in order not to cause such photoconductor fog, it is necessary to increase the triboelectric charge amount of the toner 62. When the frictional charge amount of the toner 62 is increased, the adhesion force to the developing roller 10c is increased, so that it is necessary to apply a strong rubbing force to the supply roller 64.

  Repeating rotation for a long time with such a strong rubbing force is not preferable because it causes deterioration of development characteristics such as reduction in toner charging ability and fluidity. For example, when the charge amount is reduced, the above-described photosensitive member fog is generated, and when the fluidity is reduced, development loss of halftone printing is generated.

Therefore, in the developing device 44 according to the present invention, first, the developing roller 10c is formed of a cored bar and a cylindrical semiconductive (10 ⁶ Ωcm) urethane rubber surrounding the cored bar. A developing bias of “approximately −250 V” is applied from the bias power source 68. Further, the supply roller 64 is composed of a cored bar and a cylindrical semiconductive (10 ⁶ Ωcm) urethane sponge surrounding the cored bar, and a supply bias of “approximately −500 V” is applied to the cored bar as a bias power source 69. Apply from.

Further, the doctor blade 65 is formed of an elastic metal plate, and a doctor bias of “approximately −500 V” is applied to the doctor blade 65 from the bias power source 69. The squeeze sheet 66 located upstream of the supply roller 64 is composed of a conductive member (10 ³ Ωcm), and a sheet bias voltage in a range from 0 V (0 volt) to the developing bias voltage of the developing roller 10 c is applied thereto. Application is performed by a bias power supply 71.

  When the squeeze sheet 66 is formed of a conductive member and a sheet bias voltage in the range from 0 V to the developing bias voltage of the developing roller 10c is applied thereto, the charge of the toner 62 attached to the developing roller 10c can be reduced. As a result, even with a weak rubbing force by the supply roller 64, it is possible to easily scrape off the toner in the non-development portion that has adhered and returned on the developing roller 10c.

  As described above, the developing device 44 according to the present invention employs a contact developing (roller) system in which the developing roller 10 c made of elastic rubber is pressed against the surface of the photosensitive drum 9. Further, high-speed and high-quality development with a non-magnetic one-component toner is obtained with the above-described apparatus configuration.

  Using the color image forming apparatus having the above-described apparatus configuration and the image forming process, an image having an excellent image quality with excellent followability, blade fusing property, and on-drum filming property is formed using the toner manufactured according to the present invention. I can do it.

  Hereinafter, in the embodiment of the present invention, an example of producing the nonmagnetic one-component toner of the present invention will be shown, and the present invention will be described more specifically.

[Examples of non-externally added toner]
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 38% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 53% by mass, colorant (carbon black) 5.0% by mass , 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) and 3% by mass of a mold release agent (polypropylene wax “NP056” manufactured by Mitsui Chemicals, Inc.) ) And melt kneaded with a biaxial continuous kneader. Thereafter, the mixture was cooled and pulverized and classified with a collision plate pulverizer to obtain an unextracted toner A having a mass average particle diameter of about 9 μm.

<Example 1>
Next, 100 parts by mass of this non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Nippon Aerosil Co., Ltd. Silica “RX-200”: 12 nm) 0.5 parts by mass, Alumina (Sumitomo Chemical Co., Ltd. “AKP-20”: 0.5 μm) 1 part by mass are mixed with a Henschel mixer and externally added. An agent-containing black toner was obtained. Next, the toner is exposed for a predetermined time (approximately one week, the same applies hereinafter) to absorb moisture in a constant temperature and humidity chamber (28 ° C., 80% RH) to an arbitrary amount. A toner having 5% and a cohesion of 15% was obtained.

<Example 2>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” manufactured by Aerosil Co., Ltd. and 12 parts by mass of alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) are mixed with a Henschel mixer and contain external additives. A black toner was obtained. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time and then taken out, and the toner has a moisture content (%) of 0.8% and a cohesion degree of 7%. Got.

<Example 3>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” manufactured by Aerosil Co., Ltd. and 12 parts by mass of alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) are mixed with a Henschel mixer and contain external additives. A black toner was obtained. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time, and then taken out. Toner having a toner water content (%) of 1.5% and a cohesion degree of 7% is obtained. Got.

<Example 4>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) Silica “RX-200” manufactured by Aerosil Co., Ltd. 0.5 parts by mass and 1 part by mass of alumina (“Alumina White H” manufactured by Daimei Chemical Industry Co., Ltd .: 3 μm) were mixed using a Henschel mixer, and an external additive-containing black toner. Got. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time, and then taken out. Toner having a toner water content (%) of 0.8% and a cohesion of 10% is obtained. Got.

<Example 5>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) Aerosil Silica “RX-200”: 12 nm) 0.5 parts by mass and Alumina (Sumitomo Chemical “AA-5”: 5 μm) 2 parts by mass are mixed with a Henschel mixer, and an external additive-containing black toner. Got. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time and then taken out, and the toner has a moisture content (%) of 0.8% and a cohesion degree of 12%. Got.

<Example 6>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) Aerosil Silica “RX-200”: 12 nm) 0.5 parts by mass and Strontium Titanate (“K-2”, “ST-2”: 1.4 μm) 1 part by mass are mixed with a Henschel mixer to add external additives. A contained black toner was obtained. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time and then taken out, and the toner has a toner water content (%) of 0.8% and a cohesion of 9%. Got.

<Example 7>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” manufactured by Aerosil Co., Ltd. and 12 parts by mass of barium titanate (“AP-SA” manufactured by Kyoritsu Materials Co., Ltd .: 1.5 μm) were mixed with a Henschel mixer, and the moisture content of the toner An external additive-containing black toner having (%) 0.8% and an aggregation degree of 9% was obtained.
(In this example, when mixing the external additive, purified water was sprayed by spraying to absorb the toner in an arbitrary amount.)

<Comparative Example 1>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” manufactured by Aerosil Co., Ltd. and 1 part by mass of alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) were mixed with a Henschel mixer, and the amount of toner water ( %) 2% of external additive-containing black toner having a cohesion degree of 7% was obtained.
(Also in this example, when mixing the external additives, purified water was sprayed by spraying to absorb the toner in an arbitrary amount.)

<Comparative example 2>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” manufactured by Aerosil Co., Ltd. and 1 part by mass of alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) were mixed with a Henschel mixer, and the amount of toner water ( %) An external additive-containing black toner having 0.2% and an aggregation degree of 20% was obtained.
(In this example, moisture absorption treatment is not performed.)

<Comparative Example 3>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) 0.5 parts by mass of silica “RX-200” (12 nm) manufactured by Aerosil Co., Ltd. was mixed with a Henschel mixer to obtain a black toner containing an external additive. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time, and then taken out. Toner having a toner water content (%) of 0.8% and a cohesion degree of 5% is obtained. Got.

<Comparative example 4>
100 parts by mass of the above-mentioned non-added toner A, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Japan) Aerosil Silica “RX-200”: 12 nm) 0.5 parts by mass and Alumina (Sumitomo Chemical “AKP-50”: 0.2 μm) 1 part by mass are mixed with a Henschel mixer and contain external additives. A black toner was obtained. Next, the toner is exposed for a predetermined time in a constant temperature and humidity chamber (28 ° C., 80% RH) to be absorbed for a predetermined time and then taken out, and the toner has a moisture content (%) of 0.8% and a cohesion degree of 7%. Got.

  Next, for each of the toners obtained in Examples 1 to 7 and Comparative Examples 1 to 4, the following followability evaluation test (A, B), blade fusion evaluation test, and drum filming evaluation test are used. As a result of performing each evaluation based on the results, good results were obtained in Examples 1 to 7.

[Followability evaluation test A (developing roll peripheral speed 57 mm / sec)]
The obtained toner is put on a toner cartridge (image forming unit 8 in FIG. 1) of a “Casio Computer Printer (Color Page Presto N4-612: A4 horizontal 12 sheets / min. Machine)” whose peripheral speed of the developing roll is 57 mm / sec. Filled and set.
In a normal environment (25 ° C. ± 5 ° C., 50% ± 20% RH), the plain paper “Xerox Co., Ltd .: L paper A4 (64 mg / m ² )” has a printing rate of 1.7% per A4 size. Intermittent printing was performed up to 10,000 sheets, solid image samples were printed on A3 paper every 1,000 sheets, and visual determination was performed as follows.
A: There is no difference in density between the leading edge and the trailing edge over time.
○: The density difference between the leading edge and the trailing edge is hardly observed over time. A level where there is no real problem.
X: The density difference between the leading edge and the trailing edge is severe.

[Followability evaluation test B (developing roll peripheral speed 129 mm / sec)]
The obtained toner is charged in a toner cartridge of a “Casio Computer Printer (Color Page Presto N4-612: A4 29 sheets per minute)” whose peripheral speed of the developing roll is 129 mm / sec. Evaluation was performed in the same manner as the property evaluation test A (developing roll peripheral speed 57 mm / sec).

[Blade fusion evaluation test]
Durability test is performed in the same way as the follow-up evaluation test B (developing roll peripheral speed 129 mm / sec), and it is confirmed whether there is an image defect due to blade fusion on the A3 solid image at the time of 10,000 sheets. did.
○: No problem ×: Image defect due to blade fusion.

[Drum filming evaluation test]
Durability test is performed in the same manner as the followability evaluation test B (developing roll peripheral speed 129 mm / sec), the drum surface at the time of 10,000 sheets is observed, and an image caused by drum filming on the image Checked for defects.
○: No problem Δ: Drum filming is observed, but there is no problem on the image.
X: There is an image defect due to drum filming.

The physical properties were evaluated by the following method.
[amount of water]
3 g of toner was weighed in an aluminum cup, placed in an oven heated to 120 ° C., and the change in weight after 2 hours was taken as the amount of water.
(In addition, the same result is obtained in the measurement by the Karl Fischer method.)

[Cohesion]
The apparatus used was a powder tester manufactured by Hosokawa Micron. As the sieve to be set, those having openings of 250, 150, and 75 μm from the top were used.
2 g of toner was weighed, placed gently on the top sieve stacked in three stages, vibrated for 15 seconds with an amplitude of 1 mm, and the degree of aggregation was determined as follows.
% By weight of toner remaining on sieve with aperture of 250 μm
Weight% of toner remaining on sieve with 150 μm openings × 0.6 W2
Weight% of toner remaining on sieve with aperture of 75 μm × 0.2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ W3
Aggregation degree (%) = W1 + W2 + W3

  Table 1 summarizes the evaluation results.

  From Table 1, in Examples 1 to 3, moisture was given to the toner of Comparative Example 2 in which hydrophobic silica and 0.5 μm alumina were added to the toner to make the moisture content 0.5 to 1.5%. Although the cohesion degree was lowered from 20 to 15 to 7%, both of the following results were good in followability, blade fusion, and drum filming even in a high-speed printer with a developing roll peripheral speed of 129 mm / sec. was gotten.

  Although not shown in the table, the tendency of the degree of aggregation to decrease (increase in fluidity) with a water content increase was remarkably confirmed. In addition, since the increase in fluidity is also associated with the harmful effects of fogging, as represented by Comparative Example 1, toners with various changes in water content and cohesion degree (Comparative Example 1 is different from Example 3 in water content). As a result of confirming that the amount of water and the degree of aggregation of the toner were appropriate, it was determined that the appropriate range of the amount of moisture and the degree of aggregation was 0.5 to 1.5% and the degree of aggregation was 5 to 15%.

  In the present invention, the second inorganic substance externally added to the toner may have a predetermined particle diameter, and may be other than alumina. In Examples 4 to 7, the particle diameter of alumina was changed, or external additives other than alumina were confirmed. As can be seen from Table 1, all of the followability, blade fusion, and drum filming were good. Results are obtained.

  On the other hand, in Comparative Example 3 in which the second inorganic material was not added, there were practical problems in each of the following characteristics, blade fusion, and drum filming, and the particle diameter was extremely large even when alumina was added. In the small comparative example 4, it was confirmed that there was a problem in the followability at a high speed such as a peripheral speed of the developing roll of 129 mm / sec.

  The moisture is preferably added to the toner by a humidity control method using constant temperature and humidity. From the results of Example 7, it can be seen that it may be added directly in the external addition step or a moisturizing component may be added. Further, a method of moistening a wet cloth in a moisture-proof bag after filling the toner is also conceivable.

By the way, in the above Examples 1 to 7, the evaluation was performed using an unextracted toner using carbon black as a colorant, and the influence of other colorants was not taken into consideration. However, when actually forming a color image, it is necessary to confirm other colorants.
Therefore, the effect of the colorant and the results of additional experiments to confirm the effect of the present invention on other colorants necessary for actual color image formation will be described below as another example. To do. In this example, the colorant of the non-externally added toner was changed and the toner was manufactured so as to have the same physical properties (water content and cohesion) as in Example 2.

<Another Example 1>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 39% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 53% by mass, colorant (C.I. Pigment Red 57: 1 ) 4.0% by mass, 1.0% by mass of the charge control agent (Orient Chemical Co., salicylic acid metal complex “E-84”) and 3% by mass of the mold release agent (polypropylene wax “NP056” manufactured by Mitsui Chemicals) The mixture was mixed with a mixer (manufactured by Mitsui Mining Co., Ltd.), and melt kneaded with a biaxial continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Next, 100 parts by mass of the colored fine particles, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Nippon Aerosil Co., Ltd.) Silica “RX-200”: 12 nm) 0.5 parts by mass and alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) 1 part by mass were mixed with a Henschel mixer to obtain a magenta toner. . The toner was then exposed for a predetermined time to absorb moisture in a constant temperature and humidity chamber (28 ° C., 80% RH) and then taken out, and the toner moisture content and the degree of aggregation were measured. It was 0.8% and the degree of aggregation was 7%.

<Another Example 2>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 39% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 53% by mass, colorant (C.I. Pigment Blue 15: 3 ) 4.0% by mass, 1.0% by mass of the charge control agent (Orient Chemical Co., salicylic acid metal complex “E-84”) and 3% by mass of the mold release agent (polypropylene wax “NP056” manufactured by Mitsui Chemicals) The mixture was mixed with a mixer (manufactured by Mitsui Mining Co., Ltd.), and melt kneaded with a biaxial continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Next, 100 parts by mass of the colored fine particles, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Nippon Aerosil Co., Ltd.) Silica “RX-200”: 12 nm) 0.5 parts by mass and alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) 1 part by mass were mixed with a Henschel mixer to obtain a cyan toner. . The toner was then exposed for a predetermined time to absorb moisture in a constant temperature and humidity chamber (28 ° C., 80% RH) and then taken out, and the toner moisture content and the degree of aggregation were measured. It was 0.8% and the degree of aggregation was 7%.

<Another Example 3>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 39% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 53% by mass, colorant (C.I. Pigment Yellow 17) 4 1.0% by mass, 1.0% by mass of a charge control agent (Saltylic acid metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) and 3% by mass of a mold release agent (polypropylene wax “NP056” manufactured by Mitsui Chemicals, Inc.) (Mitsui Mining Co., Ltd.) and melt kneaded with a biaxial continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Next, 100 parts by mass of the colored fine particles, 1.5 parts by mass of silicon oil-treated silica (silica “NY-50”: 30 nm, manufactured by Nippon Aerosil Co., Ltd.) as hydrophobic silica, HMDS (hexamethyldisilazane) -treated silica (Nippon Aerosil Co., Ltd.) Silica “RX-200”: 12 nm) 0.5 part by mass and alumina (“AKP-20” manufactured by Sumitomo Chemical Co., Ltd .: 0.5 μm) 1 part by mass were mixed with a Henschel mixer to obtain a yellow toner. . The toner was then exposed for a predetermined time to absorb moisture in a constant temperature and humidity chamber (28 ° C., 80% RH) and then taken out, and the toner moisture content and the degree of aggregation were measured. It was 0.8% and the degree of aggregation was 7%.

  Next, as a result of printing on the color toners obtained in the other Examples 1 to 3 based on the above-described test methods, good results were obtained with the above-described evaluation items. Therefore, finally, using the toners of the other examples 1 to 3 and the toner of the example 2, the printer device 1 in FIG. 1 ("Casio Computer printer (color page) with a developing roll peripheral speed of 129 mm / sec." Presto N4-612: A4 horizontal 29 sheets / min.)))) Filled and set in each toner unit TU (image forming units 5 to 8), and 10,000 full-color images with various image rates were printed. Good image output was obtained.

1 is a diagram schematically illustrating an internal configuration of a printer apparatus according to the present invention. 1 is an external perspective view of a printer apparatus according to the present invention. 1 is a circuit block diagram of a printer apparatus according to the present invention. FIG. 2 is a diagram schematically illustrating a main part of a developing device of a printer apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer apparatus 2 Image formation part 3 Duplex printing conveyance unit 4 Paper feed part 5-8 Image formation unit 9 Photosensitive drum 10a Charger 10b Print head 10c Developing roller 10d Transfer device 10e Cleaner 11 Paper feed cassette 11a Paper feed roller 12 Standby roller pair 13 Conveying belt 14 Drive roller 14 'Driven roller 15 Fixing unit 15a Heat roller 15b Press roller 15c Oil application roller 16 MPF tray 16a Paper feed roller 17 Switching flaps 18a to 18e Reverse conveying roller pair 19 Conveying roller pair 20 Paper discharge Roller pair 21 Paper discharge part 22 Upper part of apparatus main body 23 Lower part of apparatus main body 24 Front cover 26 I / F controller 27 Frame memory 28 Printer controller 29 Printer printing part 30 CPU
31 ROM
32 EEPROM
33 operation panel 33a key operation unit 33b display unit 44 developing device 61 hopper 62 toner 63 stirring member 64 supply roller 65 doctor blade 66 squeeze sheet 67 sealing member 68 bias power source 69 bias power source 71 bias power source

Claims (3)

An elastic developing roller for carrying and conveying the toner; and a toner layer regulating member for regulating the thickness of the toner so as to form the toner in a thin layer on the elastic developing roller. A non-magnetic one-component toner used in a developing device having a toner conveyance speed of 100 mm / second or more,
At least a mixture of a binder resin and a colorant is externally added with hydrophobized silica particles as first inorganic fine particles and second inorganic fine particles having an average particle size of 0.5 to 5.0 μm. A non-magnetic one-component toner satisfying a relationship of 0.5 ≦ a ≦ 1.5 and 5 ≦ b ≦ 15, where a represents a toner water content (%) and a aggregation degree (%) represents b.   The nonmagnetic monocomponent toner according to claim 1, wherein the second inorganic fine particles are alumina.   3. The non-magnetic one-component toner according to claim 1, wherein the binder resin is a polyester resin.

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