JP5007687B2 - Image forming method - Google Patents

Description

  The present invention relates to an electrophotographic image forming method, and more particularly to an image forming method using a one-component developer.

  In electrophotographic image formation, a toner image is formed by supplying a charged toner to an electrostatic latent image formed on an image carrier (usually an electrophotographic photosensitive member) in a contact or non-contact manner and developing it. Is transferred to plain paper and then fixed to perform image formation.

  Development methods for supplying toner to an electrostatic latent image formed on an image carrier include a two-component development method using a two-component developer composed of a carrier and toner, and a one-component developer composed of only toner. There is a one-component development system using Among these, the one-component developing method can simplify the structure of the developing device as much as no carrier is used, and is preferable for realizing a compact device. Further, in recent years, studies on colorization of electrophotography have been promoted, but a non-magnetic one-component development method using a toner that does not use a magnetic material has attracted attention as one of the promising technologies for full-color image formation.

  In image formation by the non-magnetic one-component development method, friction charging is performed by bringing toner into contact with a charging member or pressing the surface against a developing roller surface. As a developing roller used for image formation of this non-magnetic one-component developing system, one having a structure in which a rubber elastic layer is formed on the outer periphery of a conductive shaft has been used conventionally. In the developing process of the non-magnetic one-component developing system, a thin layer of toner is formed on the developing roller by a charging member such as a metal plate or a roller, and friction charging is performed. The developing roller has a structure that facilitates triboelectric charging due to the presence of an elastic layer, and at the same time, is designed so that excessive stress is not applied to the toner, and development that can provide stable charging by improving the elastic layer so far A roller has been studied (for example, see Patent Document 1).

Incidentally, with the widespread use of image forming apparatuses, there is an increasing demand for further downsizing and simplification of the apparatus. Against this background, attention has been paid to the component parts of the image forming apparatus, and studies on compactness and simplification have been made. As a means for realizing compactness and simplification of the developing roller, a hard roller having no elastic layer The developing roller called is considered. Development of a developing roller that exhibits stable triboelectric charging performance without an elastic layer has been promoted with reference to conductive resin layer forming technology on a metal shaft (see, for example, Patent Documents 2 and 3). Yes.
JP-A-8-190263 JP-A-5-257370 JP-A-5-297710

  When an image is formed using such a developing roller having no elastic layer, the nip width that regulates the toner conveyance amount compared to the developing roller having an elastic layer (the width where the regulating member and the developing roller surface are in contact). ) Becomes narrow, so it was difficult to perform stable triboelectric charging. That is, as the nip width is narrowed, the time during which frictional charging can be performed is shortened, which affects the rise of charging and makes it difficult to impart stable charging and conveyance to the toner.

  Further, since the developing roller is hard, the stress applied to the toner also increases, and the toner is deformed or crushed at the time of frictional charging, thereby affecting the toner quality. That is, fine powder is generated by the crushing of the toner, which adheres to and adheres to the surface of the developing roller and the charging member, thereby causing toner filming and causing contamination in the apparatus and the produced image. In particular, the tendency was remarkable in the toner for low-temperature fixing that is melted and fixed at a lower temperature than in the past and the oil-less fixing toner that contains a large amount of wax.

  In the present invention, in image formation using a developing roller that does not have an elastic layer, even if the nip width of the developing roller is narrow, the charging start-up property is excellent, and stable charging property and transportability are imparted to the toner. An object is to provide an image forming method.

  In addition, the present invention provides an image forming method that prevents damage to toner and external additives due to stress generated during frictional charging, and does not cause toner sticking or filming, or contamination in the apparatus or produced image. The purpose is to do.

  The present inventor has found that the above problem is solved by the configuration described below.

The invention described in claim 1
“An image forming method comprising a step of supplying a toner carried on a developing roller having no elastic layer to a photosensitive drum and developing an electrostatic latent image formed on the photosensitive drum,
The toner is obtained by adding at least a titanic acid compound to the particle surface containing at least a resin and a colorant.
An image forming method, wherein the titanic acid compound contains 100 ppm to 1000 ppm of iron. ].

  According to a second aspect of the present invention, there is provided the image forming method according to the first aspect, wherein the titanic acid compound has a number-based average particle diameter of 50 nm to 2000 nm. ].

  The invention according to claim 3 is: “The image forming method according to claim 1, wherein the titanate compound is calcium titanate or magnesium titanate. ].

  According to a fourth aspect of the present invention, “the toner has at least one temperature characteristic of a softening point temperature of 121 ° C. or lower and a glass transition temperature of 55 ° C. or lower. Item 4. The image forming method according to any one of Items 1 to 3. ].

  According to the present invention, even in an image forming environment with a narrow nip width using a developing roller that does not have an elastic layer called a so-called hard roller, it is excellent in charge rising property and exhibits stable charging property and transportability. I can do it now. Also, even if the toner is triboelectrically charged with a stronger pressing force than the developing roller, the triboelectric charging can be performed without applying a load to the toner without damaging the toner or detaching the external additive. became. Therefore, fine powder due to toner breakage or detached external additives do not adhere to or adhere to the surface of the developing roller or the charge imparting member, so that a good image that does not cause filming and contamination of the apparatus or the produced image. It became possible to form stably.

  The present invention relates to an image forming method for forming an image through a process of triboelectrically charging toner using a developing roller having a structure called an hard roller that does not have an elastic layer.

  An image forming method according to the present invention includes a two-component developing method image forming method using a two-component developer mixed with a carrier, a non-magnetic one-component developer not using a carrier, and a magnetic one-component developer. The present invention can be applied to the one-component development type image forming method used. Among them, it can be preferably used for an image forming method of a one-component developing method in which the influence of charging property is remarkable, and can be particularly preferably used for an image forming method of a non-magnetic one-component developing method.

  In the present invention, a toner containing a specific titanic acid compound is carried on a developing roller having no elastic layer, conveyed, and developed to supply a photosensitive drum, thereby realizing good image formation. It is.

  In the developing roller having no elastic layer, the nip width formed by the surface of the regulating member and the developing roller becomes narrow, so that the time for frictional charging is shortened and it is difficult to charge the toner efficiently. . In the present invention, by using a toner to which a titanic acid compound containing 100 ppm or more and 1000 ppm or less of iron is externally added, the toner is efficiently treated by the action of iron atoms contained in the titanate compound even under a narrow nip width. It seems that it became able to be charged.

  Further, on a hard developing roller having no elastic layer, a strong pressing force is applied to the toner, and the toner is easily damaged and the external additive is easily peeled off due to the collision between the toners. In the present invention, in particular, by using the titanate compound having a number-based average particle diameter of 50 nm or more and 2000 nm or less, even if the toner receives a pressing force, the presence of the titanate compound prevents the toners from colliding with each other. It seems to prevent toner damage.

  In addition, the presence of the titanate compound makes it difficult for the toner to adhere to the developing roller and the toner layer thickness regulating member, so that it is considered that contamination due to toner adhesion is also prevented. Furthermore, it is considered that the abrasiveness imparted to the toner itself by the titanate compound contributes to prevention of contamination.

  As an image forming method according to the present invention, the non-magnetic one-component developing type image forming apparatus of FIG. 1 will be described as an example. The image forming apparatus shown in FIG. 1 is a full-color image forming apparatus in which the developing device 20 shown in FIG. 2 can be mounted. The image forming apparatus on which the developing device 20 shown in FIG. 2 can be mounted is not limited to that shown in FIG. For example, the present invention can be applied to a so-called tandem type image forming apparatus in which developing devices 20 described later are arranged in series.

  The image forming apparatus shown in FIG. 1 has a needle electrode charging type charging device 16 that uniformly charges the surface of the photosensitive drum 15 to a predetermined potential around the photosensitive drum 15 that is rotationally driven, and residual toner on the photosensitive drum 15. A cleaner 17 to be removed is provided.

  The laser scanning optical system 18 scans and exposes the photosensitive drum 15 uniformly charged by the charging device 16 to form an electrostatic latent image on the photosensitive drum 15. The laser scanning optical system 18 includes a laser diode, a polygon mirror, and an fθ optical element, and print data for each of yellow, magenta, cyan, and black is transferred from the host computer to the control unit. Based on the print data of each color, a laser beam is sequentially output, and the photosensitive drum 15 is scanned and exposed to form an electrostatic latent image for each color.

  The developing device unit 30 containing the developing device 20 supplies each color toner to the photosensitive drum 15 on which the electrostatic latent image is formed to perform development. The developing device unit 30 is provided with four developing devices 20Y, 20M, 20C, and 20Bk each containing non-magnetic one-component toners of yellow, magenta, cyan, and black around the support shaft 33. Rotating to the center, each developing device 20 is guided to a position facing the photosensitive drum 15.

  The developing device unit 30 rotates around the support shaft 33 each time an electrostatic latent image of each color is formed on the photosensitive drum 15 by the laser scanning optical system 18 and stores the corresponding color toner. 20 is guided to a position facing the photosensitive drum 15. Then, each of the developing devices 20Y, 20M, 20C, and 20Bk sequentially supplies the charged color toners onto the photosensitive drum 15 to perform development.

  In the image forming apparatus of FIG. 1, an endless intermediate transfer belt 40 is provided downstream of the developing device unit 30 in the rotation direction of the photosensitive drum 15, and is driven to rotate in synchronization with the photosensitive drum 15. The intermediate transfer belt 40 comes into contact with the photosensitive drum 15 at a portion pressed by the primary transfer roller 41 and transfers the toner image formed on the photosensitive drum 15. Further, a secondary transfer roller 43 is rotatably provided so as to face the support roller 42 that supports the intermediate transfer belt 40, and the portion on the intermediate transfer belt 40 is opposed to the support roller 42 and the secondary transfer roller 43. The toner image is pressed and transferred onto the recording material S such as recording paper.

  A cleaner 50 that removes residual toner on the intermediate transfer belt 40 is provided between the developing device unit 30 and the intermediate transfer belt 40 so as to be able to contact and separate from the intermediate transfer belt 40.

  A paper feeding unit 60 that guides the recording material S to the intermediate transfer belt 40 includes a paper feeding tray 61 that houses the recording material S, and a paper feeding roller 62 that feeds the recording material S stored in the paper feeding tray 61 one by one. It comprises a timing roller 63 that feeds the fed recording material S to the secondary transfer site.

  The recording material S on which the toner image is pressed and transferred is conveyed to the fixing device 70 by a conveying means 66 constituted by an air suction belt or the like, and the toner image transferred by the fixing device 70 is fixed on the recording material S. After fixing, the recording material S is transported through the vertical transport path 80 and discharged onto the upper surface of the apparatus main body 100.

  Next, as an example of a developing device that can be used in the image forming method according to the present invention, a developing device of a non-magnetic one-component developing system shown in FIG. The developing device 20 is also referred to as a “toner cartridge” and has a unit form in which constituent members such as a developing roller are integrally disposed in addition to a toner storage portion that stores toner, and the device is loaded into the image forming apparatus as it is. It is designed so that toner can be supplied.

  The developing device 20 includes a developing roller 10, a buffer chamber 22 provided on the left side of the developing roller 10, and a hopper 23 adjacent to the buffer chamber 22. The hopper 23 corresponds to the toner storage portion described above. The developing roller 10 is rotationally driven in a counterclockwise direction in the drawing by a motor (not shown), and contacts or approaches an image carrier that is incorporated in an image forming apparatus (not shown).

  In the buffer chamber 22, a blade 24 as a toner layer regulating member is disposed in pressure contact with the developing roller 10. Here, the blade 24 regulates the toner layer thickness and functions as a charge imparting member that charges the toner carried on the developing roller. Further, a supply roller 26 is pressed against the developing roller 10. The supply roller 26 supplies toner to the surface of the developing roller 10 by being driven to rotate in the same direction as the developing roller 10 (counterclockwise direction in the drawing) by a motor (not shown). The supply roller 26 has a conductive cylindrical substrate and a foam layer formed of urethane foam or the like on the outer periphery of the substrate.

  The blade 24 that is a toner layer regulating member regulates the charge amount and adhesion amount of the toner on the developing roller 10. In addition, an auxiliary blade 25 that assists in regulating the charge amount and adhesion amount of toner on the developing roller 10 can be further provided on the downstream side of the blade 24 with respect to the rotation direction of the developing roller 10.

  The blade 24 that also functions as a charge imparting member forms a uniform thin layer of toner on the developing roller and triboelectrically charges the toner. The blade 24 is made of a member having a certain degree of elasticity, and forms a thin layer of toner on the developing roller by contacting the developing roller. The blade 24, which is a toner layer regulating member, uses stainless steel or phosphor bronze as it is, and those whose surfaces are coated with a urethane resin or an epoxy resin, or an inorganic compound such as silica or titanic acid compound by a sol-gel method or the like. A coated one can be used. In addition, an elastic material having a hardness defined by JIS A, such as silicon rubber and urethane rubber, of 40 ° to 90 ° can also be used.

  The toner thin layer formed on the developing roller has a maximum thickness of 10 toner particles, preferably 5 or less. Specifically, the peripheral speed of the electrostatic latent image carrier 11 is 100 mm / sec, the peripheral speed of the developing roller 10 is 200 mm / sec, and the pressing force of the toner regulating member 24 to the developing roller 10 is 10 to 100 N / m. In this case, a layer having a thickness of about 1.5 toner particles can be formed.

  Further, the contact force of the blade 24 to the developing roller is preferably 100 mN / cm to 5 N / cm, and particularly preferably 200 mN / cm to 4 N / cm. By setting the contact force within this range, the toner can be conveyed without causing unevenness in conveyance, so that the occurrence of image defects such as white stripes can be avoided. Further, by setting the contact force within the above range, the toner layer can be formed on the developing roller and friction charging can be performed without deforming or crushing the toner.

  In this way, in the developing device 20, the developing roller 10 and the blade 24, which is a toner layer regulating member, are disposed so as to contact each other, and a thin layer of toner is formed on the developing roller by the toner layer regulating member. Then, the toner that is thinned on the developing roller and frictionally charged is supplied onto the image carrier, whereby the electrostatic latent image formed on the image carrier can be visualized.

  A hopper 23 constituting the developing device 20 contains toner T as a one-component developer. The hopper 23 is provided with a rotating body 27 for stirring the toner T. A film-like conveying blade is attached to the rotating body 27, and the toner T is conveyed by the rotation of the rotating body 27 in the direction of the arrow. The toner T conveyed by the conveying blades is supplied to the buffer chamber 22 through a passage 28 provided in a partition wall that separates the hopper 23 and the buffer chamber 22. The shape of the conveying blade is bent while the toner T is conveyed in front of the rotation direction of the blade 27 as the rotating body 27 rotates, and returns to a straight state when the left end of the passage 28 is reached. In this way, the blades supply the toner T to the passage 28 by making the shape return straight after passing through the curved state.

  The passage 28 is provided with a valve 281 for closing the passage 28. This valve is a film-like member, one end of which is fixed to the upper side of the right side of the passage 28 of the partition wall. When the toner T is supplied from the hopper 23 to the passage 28, the valve 28 is pushed rightward by the pressing force from the toner T. Can be opened. As a result, the toner T is supplied into the buffer chamber 22.

  In addition, a regulating member 282 is attached to the other end of the valve 281. The regulating member 282 and the supply roller 26 are arranged so as to form a slight gap even when the valve 281 closes the passage 28. The regulating member 282 adjusts so that the amount of toner collected at the bottom of the buffer chamber 22 does not become excessive, so that a large amount of toner T collected from the developing roller 10 to the supply roller 26 does not fall to the bottom of the buffer chamber 22. Adjusted to

  In the developing device 20, the developing roller 10 is rotationally driven in the direction of the arrow during image formation, and the toner in the buffer chamber 22 is supplied onto the developing roller 10 by the rotation of the supply roller 26. The toner T supplied onto the developing roller 10 is charged and thinned by a blade 24 and an auxiliary blade 25, and then conveyed to a region facing the image carrier to develop an electrostatic latent image on the image carrier. To be served. The toner that has not been used for development returns to the buffer chamber 22 as the developing roller 10 rotates, and is scraped and collected from the developing roller 10 by the supply roller 26.

  The developing bias power supply 29 provided in the developing device 20 forms an alternating electric field (for example, Vpp is 2.0 kV, frequency 2 kHz) with a DC voltage power source that outputs a set value (for example, about 500 V) of the developing bias voltage Vb. It consists of an AC power supply. “Vpp” indicates a peak-to-peak voltage that is the difference between the peak and valley of the amplitude of the alternating voltage waveform.

  At the time of image formation, the electrostatic latent image carrier 11 is uniformly charged to a potential of, for example, about 800 V by a charging device (not shown), and then a predetermined portion is exposed by an optical head such as a laser. An electrostatic latent image is formed by being attenuated to a potential of about 100V.

  In the developing region, the toner formed in a thin layer on the developing roller 10 flies from the circumferential surface of the developing roller 10 by the action of an electric field formed by the developing bias voltage Vb applied from the developing bias power supply device 29 and an alternating voltage. To become a cloud cloud. Then, by supplying toner onto the electrostatic latent image carrier on which the electrostatic latent image is formed, the electrostatic latent image is developed and a toner image is formed.

  Next, the developing roller used in the present invention will be described.

  The developing roller used in the present invention has a structure having no elastic layer made of rubber or the like called an elastic layer, and is a so-called hard roller type developing roller. The surface condition of the hard roller is preferably 2 μm to 16 μm in terms of the surface roughness (Rmax) specified in JIS B0601, and the average interval (S) of the convex portions in the fine concavo-convex structure is set to 50 μm to 200 μm. It is preferable to do.

  A schematic view of a developing roller that can be used in the present invention is shown in FIG. FIG. 3 shows an example of a cross-sectional structure of the developing roller 10 usable in the present invention in (a) to (e), together with the appearance of the developing roller usable in the present invention.

  Among the developing rollers 10 usable in the present invention, those having the cross-sectional structure shown in FIGS. 3A to 3D have a conductive shaft 11 and a resin layer 12 on the shaft 11. The developing roller 10 having a cross-sectional structure represented by (a) and (c) in FIG. 3 has one resin layer around the shaft 11, and is represented by (b) and (d) in FIG. The developing roller 10 having a cross-sectional structure has a multi-layered resin layer 12 composed of a surface layer 122 and an intermediate layer 121. Further, the developing roller 10 having a cross-sectional structure represented by (c) and (d) in FIG. 3 has a structure in which particles 13 are contained in the resin layer 12 in order to impart roughness to the surface of the developing roller. It is.

  Further, the developing roller 10 having the cross-sectional structure shown in FIG. 3 (e) does not have the resin layer 12, and the surface of the developing roller is directly roughened to impart roughness to the developing roller surface. There is a typical type called a blast roller.

  The shaft 11 used for the developing roller 10 is composed of a conductive member, and specifically, a metal material such as stainless steel such as SUS304, iron, aluminum, nickel, an aluminum alloy, or a nickel alloy is preferable. Also, a conductive resin in which a conductive material such as the above-described metal powder or carbon black is filled in the resin can be used.

  The shaft 11 is manufactured by a known method. For example, a cylindrical body is formed by extrusion molding, pultrusion molding, or the like, and after applying inlay processing to both ends of the cylindrical body, a flange member is attached. Next, the cylindrical body can be manufactured by cutting and grinding the outer peripheral surface of the cylindrical body so that the outer diameter and flare of the cylindrical body are within a predetermined dimensional tolerance.

  The shaft 11 used in the developing roller 10 shown in FIG. 3E is preferably subjected to a surface roughening treatment. As a specific method of the surface roughening treatment, for example, a treatment method called sand blast treatment in which abrasive particles are mixed with compressed air and sprayed can be cited as a representative method. Examples of abrasive particles for sandblasting include alumina-based abrasives such as alundum, glass beads, metal particles such as steel shots and stainless steel beads, silicon carbide-based abrasives such as carborundum, and plastics such as nylon resin. An abrasive etc. are mentioned.

The outer diameter of the shaft 11 constituting the developing roller 10 shown in FIG. 3 is preferably 5 mm to 30 mm, and more preferably 10 mm to 20 mm. The shaft 11 preferably has a specific resistance of 1 × 10 ⁴ Ω · cm or less in order to easily leak unnecessary charges accumulated on the surface of the developing roller.

  The resin layer 12 disposed on the developing roller 10 shown in FIGS. 3A to 3D forms a toner layer on its surface and charges the toner by friction. Further, the resin layer 12 is required to exhibit a strong adhesive force between the resin layer 12 and the shaft 11. Resin which can be used for the resin layer 12 will not be specifically limited if the performance mentioned above is expressed, A well-known resin can be used. Specifically, a phenol resin, a phenol novolac resin, a polyurethane resin, a polyamide resin, a polycarbonate resin, a polyester resin, a polyimide resin, a silicone resin, a modified silicone resin, and the like can be given.

  The resin layer 12 is required to have a certain degree of conductivity, and it is preferable to disperse a conductive substance typified by carbon black. As described above, since a certain amount of conductivity is imparted to the resin layer 12 by dispersing and containing a conductive material such as carbon black in the resin layer 12, unnecessary charges remaining on the surface of the developing roller are removed from the conductive shaft. 11 can leak.

  Next, a resin that can be suitably used for a hard roller having the resin layer 12 (intermediate layer 121, surface layer 122) having a two-layer structure as shown in FIGS. 3B and 3D will be described.

  First, the resin that can be used for the intermediate layer will be described. As an example that can be suitably used as the resin for the intermediate layer, a resin mainly composed of a polyurethane resin-silica hybrid can be given. This has a polyurethane skeleton and is integrated with the silica structure, and is not particularly limited. For example, it can be obtained by the method disclosed in Japanese Patent Application Laid-Open No. 2002-220431.

  Namely, a polyurethane resin (1) obtained from at least a polyhydric alcohol and a polyvalent isocyanate compound and having a functional group reactive with an epoxy group, and an epoxy compound having at least one hydroxyl group in the molecule An alkoxy group-containing silane-modified polyurethane resin is prepared by reacting an epoxy group-containing alkoxysilane partial condensate obtained by dealcoholizing (A) with an alkoxysilane partial condensate (B). And a polyurethane resin-silica hybrid body is produced by performing hardening reaction. In addition, an isocyanate group and an amino group can be reacted by adding an amine during the reaction to form a urea bond. The coexistence of a urea bond and a urethane bond is preferable because adhesion between molecules can be improved and durability can be improved.

  Although it does not specifically limit as the said polyhydric alcohol, For example, the polyester polyol, polycarbonate polyol, polyether polyol, polyolefin polyol etc. which have a hydroxyl group at the terminal are mentioned. The polyhydric alcohol is preferably a polymer having a high molecular weight to some extent from the viewpoint of mechanical properties of the cured product and imparting elasticity, and preferably has a number average molecular weight in the range of 1000 to 6000. The number average molecular weight can be calculated as a number average molecular weight in terms of styrene by GPC (gel permeation chromatography).

  Of the polyhydric alcohols, polyester polyols and polycarbonate polyols are particularly suitable from the viewpoint of imparting performance such as high temperature durability to the polyurethane-silica hybrid.

Examples of the polyester polyol include known compounds such as the following saturated or unsaturated low-molecular glycols, alkyl glycidyl ethers, and monocarboxylic acid glycidyl ethers. That is,
・ Saturated or unsaturated various known low molecular weight glycols; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol , Neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-butynediol, dipropylene glycol, etc. ・ alkyl glycidyl ethers; n-butylglycidyl Ether, 2-ethylhexyl glycidyl ether, etc. Monocarboxylic acid glycidyl esters; Versatic acid glycidyl ester, etc.

  In addition, polyester polyols obtained by dehydrating and condensing dibasic acids and acid anhydrides corresponding thereto, dimer acid, castor oil and fatty acids thereof are also preferably used. Dibasic acids include, for example, adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, suberic acid Etc.

  Also included are polyester polyols obtained by ring-opening polymerization of cyclic ester compounds.

The polycarbonate polyol is obtained through a known condensation reaction using the following polyhydric alcohol. That is,
・ Demethanol condensation reaction of polyhydric alcohol and dimethyl carbonate ・ Deurethane condensation reaction of polyhydric alcohol and diphenyl carbonate ・ Deethylene glycol condensation reaction of polyhydric alcohol and ethylene carbonate, etc. The following saturated or unsaturated low molecular weight glycols and alicyclic glycols are exemplified.

Saturated or unsaturated low molecular weight glycols; 1,6-hexanediol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1, 5-pentanediol, octanediol, 1,4-butynediol, dipropylene glycol, etc.-Alicyclic glycols; 1,4-cyclohexanediglycol, 1,4-cyclohexanedimethanol, etc.

  Polyether polyols include polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol and the like formed by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran and the like.

  Various known polyvalent isocyanates such as aromatic, aliphatic or alicyclic can be used for the polyvalent isocyanate compound which is a constituent component of the polyurethane resin (1). Among these, diisocyanate compounds are preferable from the viewpoint of imparting elasticity.

Specific examples of the diisocyanate compound are given below. That is,
1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexa Methylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, hydrogenation Silylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane diisocyanate, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, dicarboxylic acid carboxyl group is isocyanate Dimerized isocyanate etc. converted into a group.

Moreover, it is possible to use the chain extender for extending | stretching a molecular chain for a polyurethane resin (1). Examples of the chain extender include the following. That is,
-Low molecular glycols described in the above-mentioned polyester polyol section-Dimethylolpropionic acid, dimethylolbutanoic acid, etc., glycols having a carboxyl group in the molecule-Ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, Polyamines such as isophorone diamine, dicyclohexylmethane-4,4′-diamine, dimer amine obtained by converting the carboxyl group of dimer acid into an amino group, and amino acids such as L-lysine and L-arginine.

  By using amines as chain extenders, urea bonds can be formed in the polyurethane molecule. The amount of urea bond is preferably 1 to 10 mol% with respect to the urethane bond in molar ratio, and this amount is 99 to 90 mol% of glycols and 1 to 10 mol% of amines during the reaction. Can be realized. When the urea bond and the urethane bond coexist in the molecule, the interaction due to the hydrogen bond is expressed between the polyurethane molecules, and the durability and adhesiveness of the resin layer can be improved. If the amount of urea bond is too small, the intermolecular interaction is lowered and it is difficult to improve the adhesion. If the amount of urea bond is too large, the intermolecular interaction is improved, but if the urea bond is excessive, repulsion occurs and the adhesiveness is lowered.

In the polyurethane resin, a polymerization terminator can be used to adjust the molecular weight. Examples of the polymerization terminator include the following.
(A) alkyl monoamines; di-n-butylamine, n-butylamine and the like (b) amino acids; D-alanine, D-glutamic acid and the like (c) alcohols; ethanol, isopropyl alcohol and the like (d) an alcohol having a carboxyl group Class: glycolic acid and the like.

  The functional group having reactivity with the epoxy group in the polyurethane resin (1) may be present at either the terminal or the main chain of the polyurethane resin (1). Examples of such functional groups include acidic groups such as carboxyl groups, sulfonic acid groups, and phosphoric acid groups, amino groups, hydroxyl groups, and mercapto groups. Of these, acidic groups and amino groups are preferred from the viewpoint of reactivity with epoxy groups and ease of imparting functional groups. The method for imparting an acidic group to the polyurethane resin (1) is not particularly limited. For example, the functional group may be imparted by using a compound having the aforementioned functional group as the chain extender or the polymerization terminator. it can.

  Examples of the method for producing the polyurethane resin (1) include the following. That is, there is a one-step method in which a polymer polyol, a diisocyanate compound and, if necessary, a chain extender or a polymerization terminator are reacted at once in a suitable solvent. Moreover, the two-stage method which produces a polyurethane resin (1) with the following procedures is mentioned. In the two-stage method, a polymer polyol and a diisocyanate compound are first reacted under conditions where the isocyanate group is excessive to prepare a prepolymer having an isocyanate group at the terminal of the polymer polyol. Next, this is reacted with a chain extender and, if necessary, a polymerization terminator in an appropriate solvent to produce a polyurethane resin. The two-stage method is preferable from the viewpoint of obtaining a uniform polymer solution.

  The following are mentioned as a solvent used in these manufacturing methods. The following solvents can be used alone or in combination.

-Aromatic solvents: benzene, toluene, xylene, etc.-Ester solvents: ethyl acetate, butyl acetate, etc.-Alcohol solvents: methanol, ethanol, isopropanol, n-butanol, diacetone alcohol, etc.-Ketone solvents: Acetone, methyl ethyl ketone , Methyl isobutyl ketone, cyclohexanone, etc. Other: dimethylformamide, dimethylacetamide, ethylene glycol dimethyl ether, tetrahydrofuran, etc.

  Further, the method for imparting an amino group to the polyurethane resin (1) is not particularly limited. For example, a method of reacting polyamines so that the amino group is excessive with respect to the terminal isocyanate group of the prepolymer. There is. The amount of the epoxy group-reactive functional group in the polyurethane resin (1) is not particularly limited, but usually 0.1 to 20 KOHmg / g is preferable. When it is less than 0.1 KOHmg / g, the flexibility and heat resistance of the obtained polyurethane resin-silica hybrid are lowered, and when it is more than 20 KOHmg / g, the water resistance of the polyurethane resin-silica hybrid tends to be lowered. is there. In addition, what has a urea bond in a polyurethane resin has more preferable interlayer adhesiveness.

  On the other hand, the epoxy group-containing alkoxysilane partial condensate (2) is obtained by a dealcoholization reaction between the epoxy compound (A) and the alkoxysilane partial condensate (B) as described above. If the epoxy compound (A) is an epoxy compound having one hydroxyl group in one molecule, the number of epoxy groups is not particularly limited. The epoxy compound (A) having a smaller molecular weight is more compatible with the alkoxysilane partial condensate (B) and has a higher heat resistance and adhesion-imparting effect. .

Specific examples of the epoxy compound (A) include the following. That is,
-Monoglycidyl ethers having one hydroxyl group at the molecular end; obtained by reacting epichlorohydrin with water, dihydric alcohol or phenols-Polyglycidyl ethers having one hydroxyl group at the molecular end; Products obtained by reacting epichlorohydrin with trihydric or higher polyhydric alcohols such as glycerin and pentaerythritol ・ Epoxy compounds having one hydroxyl group at the molecular end; reacting epichlorohydrin with amino monoalcohol・ A cycloaliphatic hydrocarbon monoepoxide having one hydroxyl group in the molecule; for example, epoxidized tetrahydrobenzyl alcohol, etc. Among these epoxy compounds, glycidol has the effect of imparting heat resistance and partial condensation of alkoxysilane. Most excellent because of its high reactivity with product (2) The

  The alkoxysilane partial condensate (B) is obtained by hydrolyzing a hydrolyzable alkoxysilane monomer represented by the following general formula (a) in the presence of acid or alkaline water and partially condensing it. Is used.

Formula (a): R ¹ _p Si (OR ² ) _4-p
(In the formula, p represents 0 or 1. R ¹ represents a lower alkyl group, aryl group or unsaturated aliphatic residue which may have a functional group directly connected to a carbon atom. R ² represents a methyl group. Or an ethyl group, and R ² may be the same or different.
Specific examples of the hydrolyzable alkoxysilane monomer represented by the general formula (a) are shown below.

・ Tetraalkoxysilanes; tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, etc. ・ Trialkoxysilanes; methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, ethyl Trimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane and the like.

  As these alkoxysilane partial condensates (B), those exemplified above can be used without particular limitation. However, when two or more kinds of the above exemplary compounds are used in combination, all of the alkoxysilane partial condensates (B) constituting the alkoxysilane partial condensate (B) are used. It is preferable to use 70 mol% or more of tetramethoxysilane in the alkoxysilane monomer. In addition, very stable adhesiveness is expressed when the ratio of the silane skeleton contained in the polyurethane resin-silica hybrid is 1% by mass or more and 30% by mass or less.

  The alkoxysilane partial condensate (B) is represented, for example, by the following general formula (b) or (c).

(In the formula, R ^1, .R ² showing a lower alkyl group which may have a functional group directly bonded to a carbon atom, an aryl group or an unsaturated aliphatic residue represents a methyl group or an ethyl group, R ² Each may be the same or different.)

(In the general formula (c), R ² is Formula (b) the same as R ² in.)
By using the polyurethane resin-silica hybrid described above, an intermediate layer of the resin layer 12 of the hard roller having the structure shown in FIGS. 3B and 3D can be formed. Examples of the method for forming the intermediate layer include known coating methods such as dipping, spraying, roll coating, and brush coating according to the viscosity of the resin component constituting the intermediate layer.

Next, the resin used for the surface layer will be described. Examples of the resin suitable for forming the surface layer include a silicone copolymer polyurethane resin, which can be synthesized from a compound having in its molecule a silicone skeleton having a bifunctional or higher polyvalent isocyanate group and a bifunctional or higher functional hydroxyl group. Among them, the JIS A hardness is 60 to 90 °, and the 100% modulus is 5 × 10 ^{6 to} 3 × 10 ⁷ Pa.

  Although the silicone copolymer polyurethane resin used for formation of a surface layer is not specifically limited, What is disclosed by Japanese Patent Publication No. 7-33427 etc. can be used. In the above document, when a polyurethane resin is produced by reacting a polyol component, a polyisocyanate component and, if necessary, a chain extender component, at least a part of the polyol component is a siloxane compound containing active hydrogen and a lactone. A polyurethane resin, which is a copolymer, is produced. That is, when a polyurethane resin is obtained by reacting a polyol, polyisocyanate, and a chain extender if necessary, a copolymer of a siloxane compound and lactones containing active hydrogen in all or part of the polyol is used. Is obtained.

  Preferable examples of the siloxane compound containing active hydrogen include the following.

  (1) Amino-modified siloxane

  (2) Epoxy-modified siloxane

  The epoxy-modified siloxane can be used by allowing an epoxy group in the molecule to react with a polyol, polyamine, polycarboxylic acid, or the like, so that active hydrogen is present at the terminal.

  (3) Alcohol-modified siloxane

  (4) Mercapro-modified siloxane

  (5) Carboxyl-modified siloxane

  The siloxane compound containing active hydrogen used for the surface layer is not limited to the above exemplified compounds, and known compounds that are readily available from the market can also be used. In addition, the monofunctional compound among the siloxane compounds can be incorporated into polyurethane by reacting with lactones and then reacting with the terminal NCO polyurethane.

  The lactones capable of reacting with the siloxane compound containing active hydrogen may have a substituent, and the substituent may be an alkyl group or aryl group having 1 to 5 carbon atoms, which may be the same or different. Good.

  Examples of lactones that are most suitable for forming the surface layer include the following monoalkyl-ε-caprolactones. That is, ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monopropyl-ε-caprolactone, monododecyl-ε-caprolactone, and the like. Alternatively, dialkyl-ε-caprolactones in which both of the two alkyl groups are not bonded to the carbon atom at the ε-position and are each substituted with a separate carbon atom. Further, since the carbon atom at the ε-position of the lactone ring is not di-substituted, the other two or three carbon atoms are substituted by three alkyl groups, such as trialkyl-ε-caprolactones or ethoxy- There are alkoxy-ε-caprolactones such as ε-caprolactone. Further, cycloalkyl-ε-caprolactones such as cyclohexyl-, phenyl-, benzyl-ε-caprolactone, aryl-ε-caprolactones, aralkyl-ε-caprolactones and the like can be mentioned.

  The reaction between the siloxane compound and the caprolactone is a mixture of the two and preferably reacted at a temperature of 150 to 200 ° C. for several hours to tens of hours using a suitable catalyst under a nitrogen stream. A modified polycaprolactone copolymer is produced. The siloxane compound and the caprolactone can be reacted at an arbitrary reaction ratio, but when a resin for the surface layer is prepared, the ratio of the siloxane compound is 10 to 80 parts by mass with respect to 100 parts by mass of the caprolactone. It is preferable to react. If the amount of the siloxane compound is too small, the non-adhesiveness and blocking resistance of the finally obtained polyurethane resin will be insufficient. Conversely, if the amount of the siloxane compound is too large, the optical properties of the resulting polyurethane resin will be insufficient. This is not preferable because the mechanical transparency is lowered.

  Moreover, the intermediate body obtained by making the said copolymer and the polyisocyanate mentioned later react so that at least one of the hydroxyl group of a copolymer or the isocyanate group of a polyisocyanate group may be used similarly. Examples of such intermediates are those obtained by reacting a bifunctional copolymer and a polyfunctional polyisocyanate in a rich isocyanate group, or conversely, reacting with a reactive group of the copolymer rich. Things.

  Furthermore, a polyester polyol obtained by reacting a copolymer with a polycarboxylic acid can be used in the same manner.

As the polyol that can be used in combination with the siloxane-modified polycaprolactone copolymer, any conventionally known polyol for polyurethane can be used, and among them, the terminal group is a hydroxyl group and the number average molecular weight is 300 to 4,000. The following are preferred. That is,
Polyethylene adipate, polyethylene propylene adipate, polyethylene butylene adipate, polydiethylene adipate, polybutylene adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly-ε-caprolactone diol, Examples include polyhexamethylene adipate, carbonate polyol, polypropylene glycol and the like, and those containing an appropriate amount of polyoxyethylene chain in the polyol.

  Any conventionally known organic polyisocyanate can be used as the organic polyisocyanate, and the following are preferable. That is, 4,4'-diphenylmethane diisocyanate (MDI), hydrogenated MDI, isophorone diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tri Examples include diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, and p-phenylene diisocyanate. Further, urethane prepolymers obtained by reacting these organic polyisocyanates with low molecular weight polyols or polyamines to be terminal isocyanates can also be used.

  As the chain extender, conventionally known compounds can be used. For example, ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, ethylenediamine, 1,2-propylenediamine, Methylenediamine, tetramethylenediamine, hexamethylenediamine, decamethylenediamine, isophoronediamine, m-xylylenediamine, hydrazine, water and the like are preferable.

  Of the polyurethane resins obtained from the above-mentioned materials, particularly preferred are those in which the siloxane-caprolactone copolymer segment accounts for about 10 to 80% by mass in the polyurethane resin molecules. If it is less than about 10% by mass, the non-adhesiveness, blocking resistance and the like will be insufficient, and if it exceeds 80% by mass, the resulting polyurethane resin will be insufficient in transparency and flexibility. The molecular weight is preferably 20,000 to 500,000 in terms of number average molecular weight, and most preferably 20,000 to 250,000 in terms of number average molecular weight.

  Further, the above-mentioned copolymer and polyisocyanate are reacted in an isocyanate-rich state to obtain a polyurethane-based resin having at least one free isocyanate group, which is used in combination with other film-forming resins to modify them. It can also be used as an agent.

  The polyurethane-based resin containing the siloxane caprolactone copolymer segment as described above can be produced by a conventionally known production method. These polyurethane-based resins can be produced in the absence of a solvent or in an organic solvent, but by producing in an organic solvent step by step, there is an advantage that the resulting solution can be used as it is for various applications. .

Preferred examples of such an organic solvent include the following. That is,
Ketones: methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, acetone, etc. Esters: methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, etc. Others: cyclohexane, tetrahydrofuran , Dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethyl sulfoxide, methyl cellosolve, butyl cellosolve, cellosolve acetate and the like.

  In this way, by introducing a copolymer segment of a siloxane compound and caprolactone into a polyurethane resin, it is excellent in non-adhesiveness, blocking resistance, flexibility, etc., and optically transparent polyurethane system. A resin is provided.

  Next, the electrical characteristics of the developing roller will be described.

  The conductivity of the developing roller can be evaluated by volume resistivity (volume resistance, volume resistance value). The volume resistivity can be measured by a known method.

The developing roller used in the present invention is judged to exhibit moderate conductivity when the volume resistivity measured by the following measurement method is 1 × 10 ² to 1 × 10 ⁹ Ω · cm. It is particularly preferable when the volume resistivity of the developing roller is 1 × 10 ³ to 1 × 10 ⁸ Ω · cm. When the volume resistivity of the developing roller is in the above range, it is preferable because charges generated on the surface of the developing roller leak appropriately and the leakage is appropriately suppressed.

  The volume resistivity of the developing roller can be measured, for example, by a method called a metal roller electrode method in which measurement is performed using an apparatus as shown in FIG.

  The volume resistivity measurement by the metal roller electrode method is performed by the following procedure. That is, the electrode roller 101 made of stainless steel is brought into contact with the developing roller 10 and is pressed with 9.8 N together with its own weight. While rotating the roller in this state, a voltage of +100 V is applied to one end of the developing roller 10 to measure the current value, and the volume resistivity of the developing roller is calculated from the following formula (1). Measurement conditions are shown below.

R = V / I Formula (1)
〔Measurement condition〕
Measurement environment: 23 ° C, 57RH%
Applied voltage: + 100V
Roller rotation speed: 27rpm
Electrode roller load: 9.8 N (including electrode roller weight)
Effective width of electrode roller: 230 mm (diameter 30 mm)
Measurement item: Current value (average value after 5 seconds of voltage application)
In addition, as shown in FIGS. 3C and 3D, when the particles 13 are contained in the resin layer 12 to impart roughness to the surface of the developing roller 10, the particles 13 have an average primary particle size of 5 μm. The content in the resin layer 12 is preferably 10% by mass to 50% by mass. When the surface of the developing roller 10 is roughened by the particles 13, the toner transportability on the surface of the developing roller can be improved and stabilized.

  The material of the particles 13 that can be contained in the resin layer 12 is not particularly limited. For example, crosslinked particles such as styrene resin, styrene acrylic copolymer resin, polyester resin, polyurethane resin, acrylic resin, polyethylene resin, Examples thereof include inorganic fine particles such as silica and zirconia.

  Furthermore, the developing roller used in the present invention preferably forms the resin layer 12 by applying a resin solution on the shaft 11, and the particles 13 are preferably those that do not swell and denature under the influence of a solvent. From this viewpoint, it is particularly preferable that the particles 13 have a structure excellent in solvent resistance such as a crosslinked structure. For example, an acrylic resin having a crosslinked structure can be said to be one of particularly preferable ones. The particle diameter of the particles 13 is preferably uniform from the viewpoint of uniforming the roughness of the developing roller surface.

  Next, an example of a method for manufacturing the developing roller used in the present invention will be described. Here, a manufacturing method of a resin coat type developing roller, which is one of the developing rollers usable in the present invention, will be described. A resin-coated type developing roller can be produced by applying a coating solution in which a resin is dissolved around a conductive shaft, followed by heat treatment and drying the resin layer. Further, a developing solution having a multilayer structure shown in FIGS. 3B and 3D is manufactured by applying a coating solution in which the resin is further melted on the resin layer and performing the same heat treatment. It is also possible. Hereinafter, the production procedure of the developing roller used in the present invention will be further described.

  First, a resin layer forming coating solution is prepared by mixing and dissolving a material for forming a resin layer formed around a conductive shaft in an organic solvent. That is, when preparing a coating liquid for forming a resin layer, a conductive liquid such as particles 13 or carbon black that imparts roughness to the roller surface can be included as necessary to prepare a coating liquid.

  When preparing the coating liquid, it is preferable that the components in the coating liquid become uniform. For example, when the coating liquid is prepared by adding particles 13 or carbon black that impart roughness to the resin, It is preferable to prepare such that the added components such as are uniformly dispersed in the coating solution. As a means for preparing the coating solution, for example, a sand grinder type dispersion apparatus represented by “Dynomill TILAB (manufactured by Shinmaru Enterprises Co., Ltd.)” and the like can be mentioned. In the sand grinder type dispersion apparatus, for example, dispersion processing is performed using glass beads or zirconia beads having a diameter of 0.5 mm. When preparing a coating liquid that uniformly disperses components such as carbon black and particles imparting roughness, it is necessary to perform a dispersion treatment so that the components including particles are not deformed or broken in the liquid. In this way, a coating solution is prepared.

  Next, the above-described coating liquid for forming a resin layer is applied on the conductive shaft. As the coating method, various methods can be selected according to the viscosity of the coating solution for forming the resin layer. Specific examples of the coating method include a dipping method, a spray method, a roll coating method, and a brush coating method. In the present invention, these coating methods are not limited.

  After coating the resin layer forming coating solution on the conductive shaft, drying and heat treatment (temperature; 120 to 200 ° C., processing time; 20 to 90 minutes) are performed to remove the solvent in the resin layer forming coating solution. Thereby, a resin layer is formed.

  In addition, before and after the resin layer formation according to the above procedure, a different resin layer forming coating solution is applied to develop a multi-layered development roller comprising an intermediate layer and a surface layer as shown in FIGS. It is also possible to produce. The developing roller having the intermediate layer and the surface layer shown in FIGS. 3B and 3D is also referred to as a coating roller.

  In this coating roller, the thickness of the intermediate layer and the surface layer is preferably set in a range of 3 to 30 μm, and each layer is particularly preferably set to 5 to 20 μm. The thickness of the intermediate layer and the surface layer is calculated based on a micrograph of a cross-sectional sample including the surface layer and the intermediate layer taken from the coating roller.

  In the developing roller used in the present invention, the resin layer formed on the outer periphery of the shaft 11 is not limited to the single layer or the two layers shown in FIG. 3, and an appropriate number of layers are formed. It is good also as two or more layers. Moreover, what is located in the outermost surface among the several layers which comprise the resin layer 12 can be called surface layer.

  By the above procedure, it is possible to produce a developing roller in which a resin layer is formed around a conductive shaft.

  Next, the toner used in the present invention will be described. The toner used in the present invention is a toner obtained by externally adding a titanate compound having an iron content of 100 to 1000 ppm, more preferably 100 to 500 ppm. In the present invention, a toner is prepared by externally adding a titanate compound containing a specific amount of iron atom contained in the titanate compound, so that even when a developing roller having no elastic layer with a narrow nip width is used. As a result, a good charge rise can be obtained, and stable chargeability and transportability can be secured.

  This is presumed that in addition to the high dielectric properties of titanate compounds, the presence of a specific amount of iron atoms provides an appropriate balance of charge effect performance and stabilizes the charging performance of the toner. The That is, if the number of iron atoms in the titanic acid compound is small, it is considered that the charge rise performance cannot be improved because the performance of the charging effect is reduced and charging becomes difficult. On the other hand, if there are many iron atoms in the titanic acid compound, the charge rising performance is improved, but charge leakage is likely to occur, the saturation charge amount is lowered, and it is considered that the charge is difficult to be held.

  In the present invention, the saturated charge amount of the toner can be stabilized by the presence of a titanate compound containing a specific amount of iron atoms. As a result, the toner charge can be reduced under conditions where the saturated charge amount of the toner is low, such as continuous printing where it is difficult to sufficiently stir the toner, and printing in a high temperature and high humidity environment that is susceptible to moisture. Holding performance is maintained. Further, the leakage property of the toner is maintained even under a condition where the saturation charge amount is high, as in the case of printing in a low-temperature and low-humidity environment where electric charges are difficult to leak.

  Further, by using a titanic acid compound having a number-based average particle diameter of 50 nm or more and 2000 nm or less, in addition to the effects of triboelectric charging and transportability obtained by tribocharging using a developing roller having a narrow nip width, it is subjected to triboelectric charging. The durability against strong stress can be further improved. That is, when tribocharging was performed using a developing roller having no elastic layer with a narrow nip width, the toner was not deformed or crushed even when a strong stress was applied to the toner.

  This is because the presence of titanic acid compounds of a certain size on the toner surface creates an appropriate gap between the toners so that the toners do not directly collide with each other. It is presumed that it has stopped. In addition, by adding a titanic acid compound of a certain size to the toner surface, the chance that the toner itself contacts the developing roller and the toner layer thickness regulating member is reduced, and contamination of the member by the toner can be prevented. It is also possible that Further, it is conceivable that the presence of the titanate compound imparts abrasiveness to the toner surface and makes it difficult for contamination to occur.

  As a result, there is no elastic layer that is likely to generate strong stress due to pressing even with a toner called low-temperature fixing that is considered to have low durability against stress and a toner called oilless fixing toner that contains wax. Frictional charging can be performed on the developing roller.

  The titanic acid compound used as an external additive will be further described. The titanic acid compound referred to in the present invention refers to a salt formed from titanium (IV) oxide and another metal oxide or metal carbonate, and is represented by a general formula (I) called a metatitanate. Is.

Formula (I)
M ^I ₂ TiO ₃ or M ^II TiO ₃
(In the formula, M ^I represents a monovalent metal atom and M ^II represents a divalent metal atom.)
The “iron content” as used in the present invention means the iron content contained per mass of the titanate compound. In this invention, what contains iron (atom) 100 ppm or more and 1000 ppm or less in a titanic acid compound is used. In addition, in a titanic acid compound, it is estimated that an iron atom is contained with the form of the iron compound represented by diiron trioxide, or the form taken in in the crystal lattice.

In the present invention, a titanic acid compound having a structure bonded to a divalent metal atom represented by M ^II TiO ₃ is preferably used. Specific examples of titanate compounds bonded to divalent metal atoms include calcium titanate CaTiO ₃ , magnesium titanate MgTiO ₃ , strontium titanate SrTiO ₃ , barium titanate BaTiO _{3 and the} like. Among these, calcium titanate CaTiO ₃ and magnesium titanate MgTiO ₃ are preferable from the viewpoint of influence on the environment, and calcium titanate CaTiO ₃ is particularly preferable because the charge amount is maintained at a constant level over a long period of time.

  The titanic acid compound used in the present invention has an iron content of 100 ppm or more and 1000 ppm or less, but the iron content in the titanate compound is iron such as iron chloride, iron sulfide, iron oxide, etc., which is used when preparing the titanate compound. Control is possible by adjusting the amount of compound added. Moreover, it is thought that a titanic acid compound can hold | maintain the added iron stably.

  The content of iron in the titanic acid compound can be determined by ICP-OES. In ICP-OES, titanate compounds can be decomposed and quantified as iron (Fe) ions.

  A specific measurement method by ICP-OES is shown below.

  1 g of titanate compound to be measured is taken into a dry 200 ml conical beaker. 20 ml of sulfuric acid is added as a decomposition reagent, and after performing microwave decomposition using a sealed microwave wet decomposition apparatus “MLS-1200MEGA (manufactured by MILESTONE)” or the like, it is cooled with water. At this time, the microwave decomposition is performed until there is no undissolved material. Next, the decomposition solution is transferred to a 100 ml volumetric flask, and distilled water is added to the marked line to make 100 ml to prepare a sample solution. 25 ml from the sample solution is taken into a 100 ml volumetric flask and distilled water is added up to the marked line to make 100 ml, which is used as a sample for analysis.

  The calibration curve was prepared by first preparing each standard solution so that the amount of iron in each titanate compound (calcium titanate, strontium titanate, magnesium titanate, etc.) was 0 ppm, 250 ppm, 500 ppm, 750 ppm, 1000 ppm. adjust. It is obtained by diluting these standard solutions, measuring using ICP-OES and setting the Fe wavelength to 238.204 nm, and creating a calibration curve with the above five points.

  Next, physical properties of the titanic acid compound will be described.

  The titanic acid compound used in the present invention preferably has a number-based average particle diameter of 50 nm to 2000 nm, and more preferably 50 nm to 400 nm. In the present invention, by setting the size of the titanic acid compound within the above range, it is considered that the chargeability of the toner is improved and the variation between the toner particles is reduced and stabilized. The reason for this is considered to be that a state in which the titanic acid compound is firmly fixed to the toner surface is avoided by setting the number-based particle diameter of the titanic acid compound to 50 nm or more. Since the titanate compound is not strongly adhered to the toner surface, the titanate compound containing a predetermined amount of iron atoms acts in a balanced manner to maintain the charging performance of the toner, and at the same time contributes to improved fluidity it is conceivable that.

  Further, by setting the thickness to 2000 nm or less, it is considered that the titanic acid compound used in the present invention has a particle size that is difficult to be detached from the toner surface, which contributes to an improvement in the charging property of the toner. . In other words, unused toner may be heavily agitated in the developing device and be strongly stressed, as in a print production environment with low print coverage and low toner consumption. However, the titanate compound is not easily detached from the toner surface. As a result, it is considered that the charging performance of the toner is maintained well even in such a print production environment.

The number-based average particle diameter of the titanic acid compound can be calculated from, for example, an electron micrograph. Specifically, it can be calculated by the following procedure.
(1) Take a photograph of a toner with a magnification of 30,000 times with a scanning electron microscope, and capture the photograph image with a scanner.
(2) The image processing analysis apparatus “LUZEX AP (manufactured by Nireco)” binarizes the titanate compound present on the toner surface on the photographic image, calculates the horizontal ferret diameter for 100 pieces, and calculates the horizontal ferret Let the average value of a diameter be an average particle diameter. Here, the horizontal ferret diameter means a distance between two vertical lines sandwiched between two titanic acid compounds on a photographic image.

  In addition to the method of taking a photograph of the toner as described above and using the titanate compound adhering to the toner surface, the titanate compound was photographed directly with a scanning electron microscope, and the same was taken from the photograph image. It is also possible to calculate the average particle size by the procedure.

  Moreover, the titanic acid compound used in the present invention preferably has a particle size standard deviation of 250 nm or less. By setting the standard deviation of the particle size of the titanate compound within the above range, the titanate compound in use has no variation in its charge contribution performance, and any titanate compound exhibits the same level of charge performance on the toner. It is considered that it contributes effectively in realizing uniform charging of the toner.

Here, the particle size standard deviation (sd value) represents the number-based particle size distribution of the titanate compound, and is 84% based on the number-based titanate compound by the same method as the above-described number-based average particle size measurement. It is obtained by measuring the particle size and the number-based 16% particle size and dividing the difference by two. That is, the particle size standard deviation (sd value) of the titanate compound is
Particle size standard deviation (sd value)
= [Number-based 84% particle size (D84) -Number-based 16% particle size (D16)] / 2
It is represented by

In the present invention, the titanic acid compound preferably has a BET specific surface area in the range of 5 m ² / g to 20 m ² / g. When the value of the BET specific surface area of the titanic acid compound is in the above range, it is considered that an appropriate adhesion force is secured between the titanic acid compound and the toner particle surface, and a field that facilitates charge exchange is formed. In other words, when the BET specific surface area is in the above range, the titanate compound added to the toner surface acts like a pseudo carrier or acts like a capacitor, so that the charging performance of the toner is effective. Is considered to be controlled. For example, in a low-temperature and low-humidity environment where the toner is easily overcharged, the titanic acid compound has an appropriate contact area that facilitates charge transfer to and from the toner, and releases the overcharged charge from the toner via iron atoms. It is thought that there is. On the other hand, in high-temperature and high-humidity environments where charge leakage is likely to occur, the chargeability of the toner is maintained by supplying the toner with a charge that can form a predetermined level of image by the titanate compound acting like a pseudo carrier. Presumed to be.

  Here, the BET specific surface area is the specific surface area of the particles calculated by the gas adsorption method, and the specific surface area of the particles by the gas adsorption method is calculated using a gas molecule whose adsorption occupation area is known like nitrogen gas. The specific surface area of the particles is calculated from the amount adsorbed on the particles. The BET specific surface area can accurately calculate the amount of gas molecules adsorbed directly on the solid surface (monomolecular layer adsorption amount). The BET specific surface area can be calculated using a mathematical formula called a BET formula shown below.

  As shown in the following equation, the BET equation shows the relationship between the adsorption equilibrium pressure P when in an adsorption equilibrium state at a constant temperature and the adsorption amount V at that pressure, and is expressed as follows.

Formula 1:
P / V (Po−P) = (1 / VmC) + ((C−1) / VmC) (P / Po)
Where Po: saturated vapor pressure
Vm: Monolayer adsorption amount, when gas molecules form a monolayer on a solid surface
Adsorption amount
C: Parameter related to heat of adsorption (> 0)
By calculating the monomolecular adsorption amount Vm from the above equation and multiplying this by the cross-sectional area occupied by one gas molecule, the surface area of the particles can be obtained.

  The BET specific surface area in the present invention is a value calculated by the following measurement method using an automatic specific surface area measuring apparatus “GEMINI 2360 (manufactured by Shimadzu Micromeritics)”.

  First, 2 g of titanic acid compound is filled in a straight sample cell, and the inside of the cell is replaced with nitrogen gas (purity 99.999%) for 2 hours as a pretreatment. After substitution, nitrogen gas (purity 99.999%) is adsorbed and desorbed on the composite oxide pretreated in the measuring apparatus main body, and calculation is performed by a multipoint method (7-point method).

  The amount of the titanic acid compound added to the toner is preferably 0.1 to 10.0% by mass, more preferably 0.3% to 5.0% by mass, and 0.4% by mass with respect to the total toner. % To 2.0% by mass is particularly preferable. By setting the addition amount of the titanate compound within the above range, stabilization of the charging performance of the toner is more reliably exhibited, and at the same time, the added titanate compound is not excessively detached from the toner surface. There is no possibility that the surface of the photoreceptor is locally worn by the released titanic acid compound. It is also possible to use a titanic acid compound surface-treated with silicone oil or the like. By using the surface-treated titanic acid compound, it is possible to prevent contamination of the toner layer carrier such as a carrier or a developing roller while suppressing the contamination of the toner. Charging performance such as environmental stability can be improved.

The titanic acid compound used in the present invention can be prepared by a known method. As a production method of the titanic acid compound used in the present invention, for example, there is a method of production through a titanium oxide (IV) compound TiO ₂ · H ₂ O having a hydrate form called metatitanic acid. This method is a method for producing a titanate compound typified by calcium titanate by reacting the titanium oxide (IV) compound with a metal carbonate or metal oxide such as calcium carbonate and then baking.

  The hydrolyzate of titanium oxide such as metatitanic acid is also called a mineral acid peptizer and has a liquid form in which titanium oxide particles are dispersed. A titanic acid compound is prepared by adding a water-soluble metal carbonate or metal oxide to a mineral acid peptized product made of this titanium oxide hydrolyzate, and reacting the mixture at 50 ° C. or higher while adding an alkaline aqueous solution. Is produced.

Metatitanic acid, one of the representative examples of mineral acid peptizers, has a sulfurous acid SO ₃ content of 1.0% by mass or less, preferably 0.5% by mass or less, and is adjusted to pH 0.8 to 1.5 with hydrochloric acid. And then peptized.

  As the alkaline aqueous solution used for producing the titanic acid compound, a caustic alkaline aqueous solution typified by a sodium hydroxide aqueous solution is preferably used. Moreover, as a compound made to react with the hydrolyzate of a titanium oxide, nitric acid compounds, such as strontium, magnesium, calcium, barium, aluminum, zirconium, sodium, a carbonic acid compound, a chloride compound, etc. are mentioned.

  In the production process of titanic acid compounds, the addition ratio of titanium oxide hydrate or hydrolyzate to metal oxide, etc., the concentration of titanium oxide hydrate or hydrolyzate during the reaction, temperature or addition during addition of alkaline aqueous solution The particle size of the titanate compound can be controlled by adjusting the speed and the like. Moreover, it is preferable to perform reaction in nitrogen gas atmosphere in order to prevent the production | generation of a carbonic acid compound at a reaction process.

The addition ratio (molar ratio) of the titanium oxide hydrolyzate and metal oxide during the reaction is 0.9 to 1.4, preferably 0.95 to 1.15, for metal oxide / TiO _2. It is a range. The concentration of the titanium oxide hydrolyzate in the initial stage of the reaction, 0.05 to 1.0 mol / l in terms of TiO _2, and the preferred range is 0.1 to 0.8 mol / liter.

  The higher the temperature at which the alkaline aqueous solution is added, the more crystalline the temperature is obtained, but a practical range of 50 ° C. to 101 ° C. is appropriate. In addition, the addition rate of the alkaline aqueous solution tends to affect the particle size of the titanic acid compound obtained, and the slower the addition rate, the larger the titanic acid compound is obtained, and the faster the addition rate, the smaller the particle size. Tend to form. The addition rate of the alkaline aqueous solution is 0.001 to 1.0 equivalent / h, preferably 0.005 to 0.5 equivalent / h, with respect to the charged raw material, and can be appropriately adjusted according to the desired particle diameter. is there. The addition rate of the alkaline aqueous solution can be changed in the middle depending on the purpose.

Moreover, the method of adding an iron atom in a titanic acid compound is not specifically limited, It can carry out by a well-known method. For example, as a method of adding an iron atom to calcium titanate, when a titanium oxide hydrolyzate (metatitanic acid) and calcium oxide are mixed in the manufacturing process, a compound containing an iron atom is also added to react. It is obtained by doing. Examples of the compound containing an iron atom include, in addition to iron oxide in a powder or slurry form, as preferable compounds, ferrous chloride FeCl ₂ , ferric chloride FeCl ₃ , ferrous sulfate FeSO ₄ , ferric sulfate Examples thereof include water-soluble iron oxide compounds such as Fe ₂ (SO ₄ ) ₃ . These water-soluble iron oxide compounds are preferably used in the form of their anhydrides or hydrates. As a specific production example of a titanate compound containing an iron atom, a method for producing calcium titanate by adding a ferric chloride aqueous solution when metatitanic acid and calcium carbonate are mixed is shown in the Examples.

  Next, an example of a toner structure usable in the present invention is shown in FIG. The toner shown in FIG. 5 has a structure called a core-shell structure, and can be used for the low-temperature fixing toner described above. A core-shell toner is formed by coating a resin having relatively high temperature characteristics on the surface of a region called a core containing at least a colorant and a wax in a resin having a low softening point temperature and glass transition temperature. A shell is formed.

  The toner T shown in FIG. 5 is composed of a core A made of a resin 2 containing a colorant 1 and a wax 4 and a shell B formed by coating the resin 3 on the surface of the core A. The toner T shown in FIG. 5A has a structure in which the surface of the core A is completely covered with the shell B, and the toner shown in FIG. 5B has a structure in which the shell B does not completely cover the core A. Is. Furthermore, the toner shown in (c) is a toner having a shape that is somewhat rounded as a toner by the shell B, although there are some irregularities on the surface of the core A.

  The toner of the core-shell structure shown in FIG. 5 makes it possible to provide a toner compatible with low-temperature fixing by lowering the softening point temperature and glass transition temperature of the resin constituting the core. However, as the temperature characteristics such as the softening point temperature and the glass transition temperature of the core constituent resin are set lower, the tendency that the durability when subjected to stress is lowered is prominent. In the present invention, as described above, a toner is prepared by using a titanate compound containing a specific amount of iron atom as an external additive, so that such a toner is not damaged even when subjected to stress due to pressing or the like. In addition, stable charging performance can be expressed.

  The physical properties of the toner used in the present invention will be further described.

  In the present invention, a toner formed by adding the aforementioned titanic acid compound to the surface of the colored particles having a glass transition temperature of 55 ° C. or lower can be used. The glass transition temperature of the toner can be measured using, for example, “DSC-7 differential scanning calorimeter (manufactured by PerkinElmer)” or “TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer)”.

  When measuring the glass transition temperature using the above measuring apparatus, first, 4.5 to 5.0 mg of the toner to be measured is precisely weighed to two digits after the decimal point, and an aluminum pan (Kit No. 0219-0041) is used. And set in the “DSC-7 sample holder”. The reference uses an empty aluminum pan.

  The measurement conditions are a measurement temperature of 0 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 10 ° C./min, and heat-cool-heat temperature control. When the second heat treatment is performed Analyze based on the data obtained.

  The glass transition temperature is obtained by drawing an extension line of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rise portion of the first peak and the peak vertex, and using the intersection as the glass transition temperature. Show.

In the present invention, a toner formed by adding the aforementioned titanic acid compound to the surface of the colored particles having a softening point of 121 ° C. or less can be used. The softening point of the toner can be measured, for example, by the following procedure.
(1) In an environment of a temperature of 20 ° C. ± 1 ° C. and a humidity of 50 ± 5% RH, 1.1 g of toner is placed in a petri dish and leveled, and left for 12 hours or more.
(2) After being left for 12 hours, it was pressurized with a molding machine “SSP-10A (manufactured by Shimadzu Corporation)” at a pressure of 3.74 × 10 ⁸ Pa (3820 kg / cm ² ) for 30 seconds to form a cylindrical shape having a diameter of 1 cm. A molded sample is prepared.
(3) The softening point of the molded sample is measured using a flow tester “CFT-500D (manufactured by Shimadzu Corporation)” in an environment of 24 ± 5 ° C. and 50 ± 20% RH. The measurement is performed by applying a load of 196 N (20 kgf) to the molded sample, under the conditions of a starting temperature of 60 ° C., a preheating time of 300 seconds, and a heating rate of 6 ° C./min. Under this condition, a sample is extruded from the end of preheating using a piston having a diameter of 1 cm from a hole (1 mm diameter × 1 mm) of a cylindrical die, and measurement is performed by a melting temperature measuring method of a temperature rising method. The offset method temperature (Toffset) measured with the offset value set to 5 mm is taken as the softening point of the toner.

  Next, the particle size of the toner will be described. In the present invention, it is possible to use a toner having a volume reference median diameter (D50) of 3 μm or more and 8 μm or less, and the toner belonging to such a small diameter category reproduces a high-definition dot image corresponding to the digital technology described later. It is the best thing to do.

  The volume-based median diameter (D50) is measured and calculated using, for example, an apparatus in which “Multisizer 3 (manufactured by Beckman Coulter)” is connected to a computer system equipped with data processing software “Software V3.51”. can do.

As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, and the measuring machine count is set to 25,000. To do. The aperture size of the multisizer 3 is 50 μm.

  Next, a method for producing the toner used in the present invention will be described.

  The toner used in the present invention is produced through a process of producing colored particles containing at least a resin and a colorant, and externally adding a titanic acid compound containing a specific amount of iron atoms to the surface of the produced colored particles. It is what is done.

  Here, the colored particles constituting the toner are not particularly limited in the production method thereof, and those obtained by any production method of a pulverization method or a polymerization method can be used. The colored particles are particles at a stage before the external additive is added to the toner particles, and are generally called a toner base.

  In the present invention, by adding a titanic acid compound containing a specific amount of iron atom as a toner, a toner for low-temperature fixing or wax-encapsulated toner, which has been conventionally considered to have low durability against stress, is also elastic. Triboelectric charging can be performed on a developing roller without a layer. That is, according to the present invention, it can be said that the range of selection of colored particles that can be used for image formation using a developing roller having no elastic layer is expanded. Therefore, as a representative example of the colored particles constituting the toner that can be used in the present invention, a method for producing a toner using colored particles having a core-shell structure in which wax is included in the core will be described.

  The following is a flow of toner production by the emulsion association method, which is one of the methods for producing a core-shell toner containing wax for low temperature fixing. The toner having a core-shell structure by the emulsion association method is performed through the following steps.

(1) Preparation process of resin fine particle dispersion for core formation (2) Preparation process of fine colorant particle dispersion (3) Aggregation / fusion process of resin particles for core (4) First aging process (5) Shelling process (6) Second aging step (7) Cooling step (8) Cleaning step (9) Drying step (10) External additive treatment step Hereinafter, each step will be described.

(1) Production process of resin fine particle dispersion In this process, a polymerizable monomer that forms the resin particles for the core is put into an aqueous medium and polymerized to form resin fine particles having a size of about 120 nm. It is a process. In this step, it is possible to form a resin fine particle containing a wax. In this case, the wax is dissolved or dispersed in a polymerizable monomer, and this is polymerized in an aqueous medium. Resin fine particles containing wax are formed.

(2) Colorant fine particle dispersion preparation step In this step, a colorant is dispersed in an aqueous medium to prepare a colorant fine particle dispersion having a size of about 110 nm.

(3) Aggregation and fusion process of core particles (core formation)
This step is a step of producing core particles by aggregating the above-mentioned wax-containing resin fine particles and colorant fine particles in an aqueous medium, and further fusing these agglomerated fine particles. In this step, first, an alkali metal salt, an alkaline earth metal salt, or the like is added as an aggregating agent to an aqueous medium in which resin particles containing wax and colorant particles are mixed. Subsequently, heating is performed so that the temperature becomes equal to or higher than the glass transition temperature of the resin fine particles and equal to or lower than the melting peak temperature of the mixture, thereby aggregating and simultaneously fusing the resin fine particles and the colorant fine particles to each other.

  That is, the resin fine particles and the colorant fine particles prepared by the above-described procedure are added to the reaction system, and an aggregating agent such as magnesium chloride is added to agglomerate the resin fine particles and the colorant fine particles and simultaneously melt the fine particles. To form particles. Then, when the particle size reaches the target size, a salt such as saline is added to stop aggregation.

(4) First aging step This step is a step of aging until the shape of the core becomes a desired shape by heat-treating the reaction system following the above-described aggregation / fusion step.

(5) Shelling step This step is a step of forming a shell on the core surface by adding resin fine particles for shell formation to the core dispersion formed in the first aging step.

(6) Second aging step In this step, following the shelling step, the reaction system is heat-treated to strengthen the coating of the shell on the core surface, and until the colored particles have a desired shape. This is the process of aging.

(7) Cooling step This step is a step of cooling (rapid cooling) the dispersion of the colored particles. As a cooling treatment condition, cooling is performed at a cooling rate of 1 to 20 ° C./min. The cooling treatment method is not particularly limited, and examples thereof include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

(8) Washing step This step includes a step of solid-liquid separation of the particles from the colored particle dispersion liquid cooled to a predetermined temperature in the above step, and a surface activity from the colored particles which are solid-liquid separated into wet cake-like aggregates. It consists of a cleaning process for removing deposits such as an agent and a flocculant.

  In the washing treatment, the filtrate is washed with water until the electric conductivity of the filtrate reaches 10 μS / cm. Examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, and a filtration method using a filter press and the like, and are not particularly limited.

(9) Drying step This step is a step of subjecting the washed colored particles to a drying treatment. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.

  Moreover, it is preferable that the water | moisture content of the colored particle which finished the drying process is 5 mass% or less, More preferably, it is 2 mass% or less. In addition, when the dried colored particles aggregate with a weak interparticle attractive force, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(10) External Additive Treatment Step This step is a step of preparing a toner by mixing an external additive including a titanic acid compound containing 100 ppm to 1000 ppm of iron in the colored particles after the drying treatment. As an external additive mixing device, a mechanical mixing device such as a Henschel mixer or a coffee mill can be used. It is also possible to use a known external additive other than the titanic acid compound containing the specific amount of iron atom described above.

  Through the above procedure, a toner having a core-shell structure can be produced by an emulsion association method.

  Next, the resin, colorant, wax and the like constituting the toner used in the present invention will be described with specific examples.

  As a resin that can be used in the toner used in the present invention, a polymer formed by polymerizing a polymerizable monomer called a vinyl monomer described below can be used. The polymer constituting the resin that can be used in the present invention is a polymer obtained by polymerizing at least one polymerizable monomer, and these vinyl monomers are used alone. Or it is the polymer produced combining multiple types.

Specific examples of the polymerizable monomer are shown below.
(1) Styrene or styrene derivatives Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, and the like.
(2) Methacrylic acid ester derivatives Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate Lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and the like.
(3) Acrylic acid ester derivatives Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate Lauryl acrylate, phenyl acrylate, etc.
(4) Olefins Ethylene, propylene, isobutylene and the like.
(5) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate and the like.
(6) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether and the like.
(7) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone and the like.
(8) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone and the like.
(9) Others Vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

  In addition to the above, the toner used in the present invention is formed by appropriately using the above-described polymerizable monomer having a polar group and a highly hydrophilic polymerizable monomer.

  Moreover, it is also possible to produce a resin having a crosslinked structure by using the following polyfunctional vinyls. Specific examples of polyfunctional vinyls are shown below.

  Divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and the like.

  Also, known colorants can be used for the toner. Specific colorants are shown below.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 1 to 23, C.I. I. Pigment red 30, C.I. I. Pigment red 31, C.I. I. Pigment red 32, C.I. I. Pigment red 37-41, C.I. I. Pigment red 48-58, C.I. I. Pigment red 60, C.I. I. Pigment red 63, C.I. I. Pigment red 64, C.I. I. Pigment red 68, C.I. I. Pigment red 81, C.I. I. Pigment red 83, C.I. I. Pigment red 87-90, C.I. I. Pigment red 112, C.I. I. Pigment red 114, C.I. Pigment Red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 163, C.I. I. Pigment red 166, C.I. I. Pigment red 170, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 207, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. Pigment red 238, C.I. I pigment red 269 etc. are mentioned.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 162, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Further, as a colorant for green or cyan, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 17, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 2, 6, 14, 15, 16, 19, 21, 21, 33, 44, 56, 61, 77, 79, 80, 81, 82, the same 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used.

  These colorants can be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the whole toner.

Examples of waxes that can be used for the toner include the following known waxes.
(1) Polyolefin wax Polyethylene wax, polypropylene wax, etc. (2) Long-chain hydrocarbon wax, paraffin wax, sazol wax, etc. (3) Dialkyl ketone wax, distearyl ketone, etc. (4) Ester wax Carnauba wax, Montan Wax, trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, 1,18-octadecanediol di Stearate, trimellitic trimellitic acid, distearyl maleate, etc. (5) Amide wax Ethylenediamine dibehenyl amide, trimellitic acid triste Riruamido like.

  The melting point of the wax is usually 40 to 125 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. By setting the melting point within the above range, the heat-resistant storage stability of the toner is ensured, and stable toner image formation can be performed without causing cold offset or the like even when fixing at a low temperature. Further, the wax content in the toner is preferably 1% by mass to 30% by mass, and more preferably 5% by mass to 20% by mass.

  As described above, the toner used in the present invention includes inorganic particles and organic particles having an average primary particle size of 4 to 800 nm known as an external additive, in addition to a titanic acid compound containing a specific amount of iron atoms. Etc. can be used together.

  The type of external additive that can be used in combination with the titanic acid compound is not particularly limited, and examples thereof include known inorganic fine particles, organic fine particles, and lubricants as listed below.

  Examples of the inorganic fine particles that can be used in combination include silica, titania, alumina, and the like, and those obtained by hydrophobizing these inorganic fine particles may be used. Examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H-200 manufactured by Hoechst, and Cabot. Commercially available products TS-720, TS-530, TS-610, H-5, MS-5, and the like manufactured by the company are listed.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having an average primary particle size of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used.

  In order to further improve the cleaning property and transfer property, a metal salt of a higher fatty acid called a so-called lubricant can be used as an external additive. Specific examples of the higher fatty acid metal salt include the following. That is, salts of zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, salts of manganese, iron, copper, magnesium, etc., zinc palmitate, salts of copper, magnesium, calcium, etc., linoleic acid There are salts of zinc, calcium and the like, and zinc and calcium of ricinoleic acid.

  The amount of these external additives added to the toner is preferably 0.1 to 10.0% by mass with respect to the total toner including the above-described titanic acid compound containing iron atoms. Moreover, as an addition method of an external additive, the method of adding using various well-known mixing apparatuses, such as a Turbuler mixer, a Henschel mixer, a Nauta mixer, and a V-type mixer, is mentioned.

Examples of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
1. Production of “Developing Rollers 1-4” “Developing Rollers 1-4” were produced by the following procedure.
(1) Production of “Developing Roller 1” In a reactor equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube, 1000 parts by mass of polycarbonate diol “Placcel CD220 (manufactured by Daicel Chemical Industries)” (number average molecular weight 2000) And 278 parts by mass of isophorone diisocyanate were charged and reacted at 100 ° C. for 6 hours under a nitrogen stream to form a prepolymer having a free isocyanate value of 3.44%. To this, 548 parts by mass of methyl ethyl ketone was added to obtain a uniform solution of urethane prepolymer.

  Next, 1000 parts by mass of the urethane prepolymer solution was added in the presence of a mixture consisting of 71.8 parts by mass of isophoronediamine, 4.0 parts by mass of di-n-butylamine, 906 parts by mass of methyl ethyl ketone, and 603 parts by mass of isopropyl alcohol. And reacted at 50 ° C. for 3 hours. In this way, a polyurethane resin solution (hereinafter referred to as “polyurethane resin (1A)” solution) was prepared. The obtained “polyurethane resin (1A)” solution had a resin solid content concentration of 30% and an amine value of 1.2 KOH (mg / g).

  On the other hand, in a reactor equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction pipe, 1400 parts by mass of glycidol “Epiol OH (manufactured by NOF Corporation)”, tetramethoxysilane partial condensate “methyl silicate 51” (Manufactured by Tama Chemical Co., Ltd.) ”(average number of Si: 4) 8957.9 parts by mass, heated to 90 ° C. while stirring under a nitrogen stream, and then reacted by adding 2 parts by mass of dibutyltin dilaurate as a catalyst. I let you. During the reaction, methanol in the water separator was distilled off, and the mixture was cooled when the amount reached about 630 parts by mass. The time required for cooling after raising the temperature was 5 hours. Subsequently, methanol remaining in the system was removed under reduced pressure at 13 kPa for about 10 minutes. In this way, “epoxy group-containing alkoxysilane partial condensate (2A)” was produced.

  Furthermore, after heating 500 parts by mass of the aforementioned “polyurethane resin (1A)” to 50 ° C. in the same reaction apparatus, 10.95 parts by mass of the “epoxy group-containing alkoxysilane partial condensate (2A)” was added, The reaction was carried out at 60 ° C. for 4 hours under a nitrogen stream to produce an “alkoxy group-containing silane-modified polyurethane resin” used as a coating resin.

  100 parts of the above-mentioned “alkoxy group-containing silane-modified polyurethane resin”, 30 parts of “Ketjen black”, 40 parts of crosslinked urethane resin particles “Bernock CFB100 (Dainippon Ink and Chemicals)” having a number average primary particle size of 20 μm, Were mixed and dispersed to prepare a coating solution. This coating solution is applied to the peripheral surface of a shaft made of SUS303 having a diameter of 10 mm so that the thickness when dried is 15 μm, and heat treatment at 100 ° C. is performed for 1 hour to form a resin layer. “Developing roller 1” having the cross-sectional structure shown in FIG. “Developing roller 1” had an Rmax of 8 μm and S of 120 μm.

(2) Production of “Developing Roller 2” In the production of “Developing Roller 1”, a crosslinked urethane resin particle “Barnock CFB100 (Dainippon Ink & Chemicals, Inc.)” having a number average primary particle size of 20 μm was not added. A coating solution was prepared in the same procedure except that. This coating solution is applied to the peripheral surface of a shaft made of SUS303 having a diameter of 10 mm so that the thickness when dried is 20 μm, and heat treatment at 100 ° C. is performed for 1 hour to form a resin layer. “Developing roller 2” having the cross-sectional structure shown in FIG. “Developing roller 2” had an Rmax of 3 μm and S of 52 μm.

(3) Production of “Developing Roller 3” In a reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a reflux condenser, 310 parts of ε-caprolactone and 150 parts of alcohol-modified siloxane oil (Exemplified Compound 3-3) Then, 0.05 part of tetrabutyl titanate was added and reacted at 180 ° C. for 10 hours under a nitrogen stream to prepare a polysiloxane-polyester copolymer having a hydroxyl value of 37, an acid value of 0.40, and a number average molecular weight of 3030.

  150 parts of the copolymer and 27 parts of 1,4-butanediol were dissolved in a mixed solvent of 200 parts of methyl ethyl ketone and 100 parts of dimethylformamide and stirred well at 60 ° C. To this, 91 parts of hydrogenated diphenylmethane diisocyanate (also abbreviated as hydrogenated MDI or H12MDI) dissolved in 188 parts of dimethylformamide was gradually added dropwise. After completion of the dropwise addition, the solution was reacted at 80 ° C. for 6 hours to prepare a silicone copolymer polyurethane resin solution used as a coating resin. This solution was very transparent, had a solid concentration of 35% and a viscosity of 35.5 Pa · s (25 ° C.).

  A coating solution for forming a surface layer was prepared by mixing and dispersing 100 parts of the silicone copolymer polyurethane resin, 30 parts of ketjen black, and 40 parts of a crosslinked urethane resin having a number average primary particle size of 20 μm.

  After producing the “developing roller 1”, the surface layer forming coating solution is applied so that the thickness when dried is 5 μm, and heat treatment at 100 ° C. is performed for 40 minutes to form a second resin layer. The “developing roller 3” having the cross-sectional structure shown in FIG. “Developing roller 3” had an Rmax of 14 μm and S of 140 μm.

(4) Production of “Developing Roller 4” The surface of an aluminum shaft having a diameter of 11 mm was subjected to a sandblasting treatment using alundum abrasive grains “Morundum A # 400 (manufactured by Showa Denko KK)”, and JIS B- Unevenness was imparted so that the center line average roughness specified by 0601 would be 15 μm. The shaft was processed in this manner to produce a blast roller type “developing roller 4” having a cross-sectional structure shown in FIG. “Developing roller 4” had an Rmax of 10 μm and S of 78 μm.

2. 2. Production of “Toners 1 to 22” 2-1. Production of “titanic acid compounds 1-18” (1) Production of “titanic acid compound 1” Desulfurization treatment was performed by adjusting the pH of the metatitanic acid dispersion to 9.0 with a 4.0 mol / liter sodium hydroxide aqueous solution. Then, a 6.0 mol / liter hydrochloric acid aqueous solution was added to adjust the pH to 5.5, followed by neutralization treatment. Then, water was added to the cake of metatitanic acid prepared by filtering and washing the metatitanic acid dispersion, and after preparing a dispersion corresponding to 1.25 mol / liter in terms of titanium oxide TiO ₂ , 6.0. The pH was adjusted to 1.2 with a mol / liter hydrochloric acid aqueous solution. Then, the temperature of the dispersion was adjusted to 35 ° C., and stirred at this temperature for 1 hour to peptize the metatitanic acid dispersion.

Metatitanic acid corresponding to 0.156 mol in terms of titanium oxide TiO ₂ is collected from the metatitanic acid dispersion that has been subjected to the peptization treatment and charged into a reaction vessel, followed by calcium carbonate CaCO ₃ aqueous solution and second chloride. An aqueous iron solution was charged into the reaction vessel. Thereafter, a reaction system was prepared so that the titanium oxide concentration was 0.156 mol / liter. Here, calcium carbonate CaCO ₃ is added in a molar ratio of 1.15 to titanium oxide (CaCO ₃ / TiO ₂ = 1.15 / 1.00), and ferric chloride is added to titanium oxide. The molar ratio was 0.009 (FeCl ₃ / TiO ₂ = 0.009 / 1.000).

  Nitrogen gas is supplied into the reaction vessel, and the reaction vessel is left in a nitrogen gas atmosphere by allowing it to stand for 20 minutes, and then a mixed solution composed of metatitanic acid, calcium carbonate, and ferric chloride is heated to 90 ° C. Warmed up. Subsequently, an aqueous sodium hydroxide solution was added over 24 hours until the pH reached 8.0, and then stirring was continued at 90 ° C. for 1 hour to complete the reaction.

  After completion of the reaction, the inside of the reaction vessel was cooled to 40 ° C., and the supernatant was removed under a nitrogen atmosphere. Then 2500 parts by mass of pure water was put into the reaction vessel, and decantation was repeated twice. After carrying out decantation, the reaction system was filtered with Nutsche to form a cake, and the obtained cake was heated to 110 ° C. and dried in air for 8 hours.

  The obtained dried calcium titanate was put into an alumina crucible, dehydrated at 930 ° C. and fired. After the firing treatment, calcium titanate is put into water, wet-grinded with a sand grinder to obtain a dispersion, 6.0 mol / liter hydrochloric acid aqueous solution is added to adjust the pH to 2.0, Excess calcium carbonate was removed. After the removal treatment, a wet hydrophobization treatment was performed on calcium titanate using a silicone oil emulsion (dimethylpolysiloxane emulsion) “SM7036EX (manufactured by Toray Dow Corning Silicone Co., Ltd.)”. In the hydrophobization treatment, 0.7 parts by mass of the silicone oil emulsion is added to 100 parts by mass of calcium titanate solid content, and the mixture is stirred for 30 minutes.

  After the wet hydrophobization treatment, 4.0 mol / liter sodium hydroxide aqueous solution is added, pH is adjusted to 6.5, neutralization treatment is performed, followed by filtration and washing, and drying at 150 ° C. Processed. Furthermore, the pulverization process was performed for 60 minutes using the mechanical grinder, and the "titanate compound 1" which is a calcium titanate containing an iron atom was produced.

The produced “titanic acid compound 1” was measured to have an iron content of 102 ppm by ICP-OES. Further, when the volume-based particle size, particle size standard deviation (SD value), and BET specific surface area of the produced “titanate compound 1” were measured by the above-described methods, the volume-based particle size was 205 nm, and the particle size standard deviation (SD Value) was 110 nm, and the BET specific surface area was 16.3 m ² / g.

(2) Production of “titanic acid compounds 2-7” In the production of “titanic acid compound 1”, the addition amount of ferric chloride FeCl ₃ was changed as shown in Table 1 in molar ratio to titanium oxide. Otherwise, “titanic acid compounds 2 to 7” were produced in the same manner. The obtained values are shown in Table 1 described later.

(3) Production of “titanic acid compounds 8-12” Production of “titanic acid compound 1” takes 90 minutes for peptization at a liquid temperature of 35 ° C. and 90 minutes for mechanical grinding equipment. The “titanic acid compound 8” was prepared in the same procedure except that each was extended. Further, “titanic acid compound 9” was prepared in the same manner as in the preparation of “titanic acid compound 1” except that the peptization time at a liquid temperature of 35 ° C. was extended to 90 minutes.

  In addition, in the production of the “titanic acid compound 1”, the same procedure was followed except that the peptization treatment at a liquid temperature of 35 ° C. was changed to 50 minutes and the crushing treatment using a mechanical pulverizer was changed to 45 minutes. Compound 10 "was made. The same procedure was followed except that the preparation of the “titanic acid compound 1” was shortened to 20 minutes for the peptization treatment at a liquid temperature of 35 ° C. and 30 minutes for the pulverization treatment using a mechanical pulverizer. Thus, “titanic acid compound 11” was produced. Furthermore, in the production of the “titanic acid compound 1”, the same procedure was followed except that the time for the peptization treatment at a liquid temperature of 35 ° C. was reduced to 15 minutes and the pulverization treatment using a mechanical pulverizer was shortened to 20 minutes. “Titanic acid compound 12” was produced.

(4) Production of “titanium acid compounds 13 to 18” “Titanium” made of strontium titanate was prepared in the same manner except that strontium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 2”. Acid compound 13 "was prepared. Further, “titanic acid compound 14” made of strontium titanate was produced in the same manner except that strontium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 4”.

  In addition, “titanic acid compound 15” made of magnesium titanate was produced by the same procedure except that magnesium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 2”. In addition, “titanic acid compound 16” made of magnesium titanate was produced by the same procedure except that magnesium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 4”.

  Furthermore, “titanic acid compound 17” made of barium titanate was produced in the same manner except that barium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 2”. Further, “titanic acid compound 18” made of barium titanate was produced in the same manner except that barium carbonate was used instead of calcium carbonate used in the production of “titanic acid compound 4”.

  Table 1 shows the iron atom content, number average particle size, particle size standard deviation, and BET specific surface area of “titanate compounds 1 to 18” produced by the above procedure.

2-2. Preparation of “colored particles A and B” [A] Preparation of “colored particles A” (1) Preparation of “core-forming resin fine particles A1” A dispersion of “core-forming resin fine particles A” was prepared by the following procedure. .

(A) First-stage polymerization After adding the following compound to a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, the mixture is heated to 80 ° C. to prepare “monomer mixed solution 1” did.

Styrene 109 parts by weight n-butyl acrylate 55 parts by weight Methacrylic acid 12 parts by weight n-octyl mercaptan 2.9 parts by weight Paraffin wax “HNP-57 (manufactured by Nippon Seiwa Co., Ltd.)” 70 parts by weight On the other hand, anionic surface activity A surfactant solution was prepared by dissolving 1.5 parts by mass of the polyoxy (2) dodecyl ether sulfate sodium salt in 650 parts by mass of ion-exchanged water, and the surfactant solution was heated to 90 ° C. deep.

  The above-mentioned “monomer mixed solution 1” is added to the surfactant solution, and the monomer mixed solution is added using a mechanical disperser “CLEAMIX (manufactured by M Technique)” having a circulation path. Was dispersed in a surfactant solution. A dispersion liquid containing emulsified particles having a dispersion particle diameter of 210 nm is prepared by the dispersion treatment for 3 hours, and 700 parts by mass of ion-exchanged water heated to 90 ° C. is added to the dispersion liquid.

  Further, an initiator aqueous solution prepared by dissolving 3 parts by mass of potassium persulfate (KPS) in 120 parts by mass of ion-exchanged water was added to the dispersion, and the system was heated to 82 ° C., and then heated and stirred for 3 hours. Polymerization (first stage polymerization) was carried out to prepare “resin particle dispersion a1”.

(B) Second-stage polymerization To the “resin particle dispersion a1”, an initiator aqueous solution prepared by dissolving 120 parts by mass of ion-exchanged water and 3 parts by mass of potassium persulfate (KPS) was added. Then, “monomer mixed solution 2” made of the following compound was added dropwise over 1 hour.

Styrene 212 parts by mass n-butyl acrylate 86 parts by mass n-octyl mercaptan 2.6 parts by mass After completion of dropping, the mixture was heated and stirred for 3 hours to conduct polymerization (second stage polymerization), and then the reaction system was 28 ° C. The “resin fine particle A1 dispersion liquid” having a two-layer structure was produced. The “resin fine particle A1” constituting the “resin fine particle A1 dispersion” had a glass transition temperature of 40.0 ° C.

(2) Production of “shell forming resin fine particles A2” Anionic surface activity used in the production of “core forming resin fine particles A1” in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device. A surfactant solution was prepared by dissolving 2.0 parts by mass of the agent in 3000 parts by mass of ion-exchanged water. While this surfactant solution was stirred at a stirring speed of 230 rpm under a nitrogen stream, the internal temperature was raised to 80 ° C.

On the other hand, the following compound is added and mixed to prepare “monomer mixed solution 2”. That is,
Styrene 544 parts by mass n-butyl acrylate 160 parts by mass Methyl methacrylate 96 parts by mass n-octyl mercaptan (NOM) 20 parts by mass

  After adding an initiator solution prepared by dissolving 10 parts by mass of potassium persulfate (KPS) in 200 parts by mass of ion-exchanged water in the surfactant solution, the above “monomer mixed solution 2” is added over 3 hours. It was dripped. Then, the system was heated to 80 ° C., and polymerization was carried out by heating and stirring for 1 hour to prepare a dispersion of “shell forming resin fine particles A2”.

(3) Preparation of “Colorant Dispersion 1” A solution prepared by stirring and dissolving 90 parts by mass of sodium dodecyl sulfate in 1600 parts by mass of ion-exchanged water was stirred, and carbon black “Regal 330R ( 420 parts by mass of “Cabot Corporation” was gradually added. Subsequently, a dispersion process was performed using a stirrer “CLEARMIX (M Technique Co., Ltd.)” to prepare “Colorant Dispersion Liquid 1”. When the particle size of the colorant particles in “Colorant Dispersion 1” was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 110 nm.

(4) Core formation (Salting out / fusion (association / fusion) process) (core formation)
In a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, nitrogen introduction device,
450 parts by mass of “resin fine particle A1” dispersion (solid content conversion)
Ion-exchanged water 1100 parts by mass “Colorant Dispersion 1” 100 parts by mass (solid content conversion)
The liquid temperature was adjusted to 30 ° C. Thereafter, a 5 mol / liter aqueous sodium hydroxide solution was added to adjust the pH to 10.0.

  The reaction system was allowed to stir, and in this state, an aqueous solution prepared by dissolving 60 parts by mass of magnesium chloride hexahydrate in 60 parts by mass of ion-exchanged water was added to the reaction system over 10 minutes. After the addition, the mixture was allowed to stand for 3 minutes, and then the temperature increase was started. The system was heated to 80 ° C. over 60 minutes, and the particles were grown by associating the resin particles while maintaining the temperature at 80 ° C. . Particle growth was confirmed by measuring the particle size of the associated particles using “Multisizer 3 (manufactured by Beckman Coulter)”. When the volume-based median system (D50) reaches 5.5 μm, an aqueous solution obtained by dissolving 40.2 parts by mass of sodium chloride in 1000 parts by mass of ion-exchanged water is added to the reaction system to stop particle growth. I let you.

  Further, the temperature of the reaction system was set to 70 ° C. for 1 hour, and the mixture was subjected to aging treatment by heating and stirring to continue the aging treatment, thereby forming “core A”. The average circularity of “Core A” was measured by “FPIA2000 (manufactured by Systex)” and found to be 0.912.

(5) Formation of Shell Next, 550 parts by mass (in terms of solid content) of the above-mentioned “core A” dispersion was set to 65 ° C.,
"Resin fine particle A2" dispersion 50 parts by mass (solid content conversion)
Further, an aqueous solution prepared by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water was added over 10 minutes.

  Next, the temperature of the system was raised to 70 ° C., and stirring was continued for 1 hour to fuse “resin fine particles A2” to the surface of “core 1”. Thereafter, the system was heated to 75 ° C. and stirred for 20 minutes to perform an aging treatment to form a shell.

  Furthermore, an aqueous solution prepared by dissolving 40.2 parts by mass of sodium chloride in 1000 parts by mass of ion-exchanged water was added, and the mixture was cooled to 30 ° C. under the condition of 8 ° C./min. The produced colored particles were filtered, washed repeatedly with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to produce “colored particles A” having a structure in which the core surface was covered with a shell. The shell coverage on the “colored particle A” surface was evaluated and found to be 98%. The “colored particles A” had a glass transition temperature of 40 ° C. for the core, 55 ° C. for the shell, 42 ° C. for the core-shell particles, and 110 ° C. for the softening point.

[B] Production of “Colored Particle B” (1) Production of “Resin Fine Particle B1” 20 parts by mass of dodecylbenzenesulfonic acid was dissolved in 2400 parts by mass of pure water, and the solution was heated to 95 ° C. In the state, oil droplets formed by dispersing the following compounds with an ultrasonic dispersing device were added and reacted at 95 ° C. for 24 hours to form a polyester resin.

Azelaic acid 320 parts by mass 1,10-decanediol 280 parts by mass Styrene 800 parts by mass Butyl acrylate 200 parts by mass The molecular weight of the obtained polyester resin part was measured by gel permeation chromatography, and the weight average molecular weight was obtained. (Mw) 20,000, number average molecular weight (Mn) 10,000, glass transition temperature Tg was 60 ° C., and softening point temperature was 125 ° C.

  Next, after lowering the temperature of the reaction system to 80 ° C., an initiator aqueous solution formed by dissolving 1.5 parts by mass of potassium persulfate (KPS) in 60 parts by mass of ion-exchanged water was added over 5 hours. A styrene acrylic resin was formed by polymerization. In this way, “resin fine particles B1” made of a polyester resin and a styrene acrylic resin were produced.

  When the styrene acrylic resin part was separated from the resin fine particles B1 and the molecular weight was measured by gel permeation chromatography, the weight average molecular weight (Mw) was 52,000, the number average molecular weight (Mn) was 9,000, and the molecular weight distribution (Mw / Mn) 5.7. The glass transition temperature Tg was 53 ° C. and the softening point temperature was 118 ° C. Further, the size of the “resin fine particles B1” was 210 nm in terms of number average primary particle diameter.

(2) Production of “Colorant Dispersion 2” 10 parts by mass of anionic surfactant sodium dodecylbenzenesulfonate was stirred and dissolved in 300 parts by mass of ion-exchanged water. While stirring this solution, 70 parts by mass of carbon black “Regal 330R” (Cabot Corporation) is gradually added as a colorant, and then a mechanical disperser “CLEAMIX (M Technique Co., Ltd.)” A “colorant dispersion liquid 2” was produced by carrying out a dispersion treatment using

  When the colorant particle diameter of the produced “colorant dispersion liquid 2” was measured using an electrophoretic light scattering photometer “ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)”, the mass average particle diameter was 92 nm.

(3) Preparation of “Wax Dispersion 1” 10 parts by mass of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 300 parts by mass of ion-exchanged water with stirring. This dissolved solution was heated to 90 ° C., and 70 parts by weight of “Carnauba wax (refined carnauba wax No. 1)” was dissolved at 90 ° C. while stirring the dissolved solution in this state. Was gradually added. Next, using a mechanical disperser “CLEAMIX (M Technique Co., Ltd.)”, the dispersion treatment was performed at 90 ° C. for 7 hours, and then cooled to 30 ° C. to obtain “Wax Dispersion 1 Was made.

  When the wax particle diameter of the produced “wax dispersion 1” was measured with an electrophoretic light scattering photometer “ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)”, the mass average particle diameter was 95 nm.

(4) Production of “colored particles B” In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, the above-mentioned “resin fine particles B1”, 300 parts by mass of ion-exchanged water, “colorant dispersion 2” And “wax dispersion 1” were added, and the temperature in the reaction vessel was adjusted to 30 ° C. The “resin fine particles B1”, “colorant dispersion 2”, and “wax dispersion 1” prepared in the above-described procedure were directly put into the reaction vessel.

  Next, a 5 mol / liter sodium hydroxide aqueous solution was added to the reaction vessel to adjust the pH to 10.0, and then the magnesium chloride hexahydrate 10 was added under a state where the charge was stirred. An aqueous solution in which part by mass was dissolved in 200 parts by mass of ion-exchanged water was added over 10 minutes. The magnesium chloride hexahydrate was allowed to stand for 1 minute after the addition, and then the temperature was raised and the temperature was raised to 90 ° C. over 10 minutes to aggregate the fine particles.

  The growth of the particles was confirmed by measuring the particle size of the aggregated particles using “Multisizer 3 (manufactured by Beckman Coulter)”. When the volume-based median system (D50) reached 5.5 μm, an aqueous solution in which 2 parts by mass of sodium chloride was dissolved in 20 parts by mass of ion-exchanged water was added to stop particle growth. Furthermore, by heating the reaction system to 95 ° C. and continuing stirring in this state for 10 hours, the fusion of fine particles is continued to control the shape, and then the reaction system is operated at 8 ° C./min. Cooled to 30 ° C. The produced colored particles were filtered, washed repeatedly with ion-exchanged water at 45 ° C., and then dried with hot air at 40 ° C. to prepare “colored particles B” having a structure in which the core surface was covered with a shell. The “colored particles B” obtained had a glass transition temperature of 55 ° C. and a softening point temperature of 121 ° C.

2-3. Preparation of “Toners 1 to 19” (1) Preparation of “Toner 1” The following were added as external additives to 100 parts by mass of “Colored Particle A”. That is,
“Titanate Compound 1” 2.0 parts by mass Hydrophobic silica (BET value 380, hydrophobized with hexamethyldisilazane)
1.0 part by mass Hydrophobic silica (BET value 90, hydrophobized with hexamethyldisilazane)
1.0 part by mass The external additive treatment was carried out using a Henschel mixer “FM10B (Mitsui Miike Chemical Co., Ltd.)” with a stirring blade convergence of 35 m / sec and a treatment time of 20 minutes at a temperature of 30 ° C. Then, coarse particles were removed using a sieve having an opening of 90 μm to prepare “Toner 1”.
(2) Production of “Toners 2 to 19” As shown in Table 2, “toners 2 to 19” were produced by combining titanate compounds and colored particles.

22 types of evaluation samples were prepared by combining the “toners 1 to 19” produced in this way and the “developing rollers 1 to 4” described above and mounting them in the developing device shown in FIG. The combination of the toner and the developing roller in each evaluation sample is as shown in Table 3 to be described later. The gap between the developing roller and the toner layer regulating member was adjusted to 20 μm.
3. Evaluation Experiments Table 3 shows the evaluation samples described above for developing devices used in a color laser printer “Magicor 5440DL (manufactured by Konica Minolta Business Technologies, Inc.)” which is a commercially available non-magnetic one-component developing image forming apparatus. In the same way, the toner and the developing roller were mounted in combination. The combination of the toner having the configuration of the present invention and the developing roller is “Examples 1 to 15”, and the combination of the toner and the developing roller that is not included in the configuration of the present invention is “Comparative Examples 1 to 7”. Evaluation is performed under a high temperature and high humidity environment (temperature 30 ° C., humidity 85% RH) and a low temperature and low humidity environment (temperature 10 ° C., humidity 15% RH). Each occurrence of toner fixation was performed.

<Evaluation of charging start-up performance>
Immediately after outputting a solid black image print, a white paper was printed, and the fog density on the white paper was measured to evaluate the charge rising performance. That is, it was evaluated that the lower the fog density, the better the charge rising performance.

  To measure the fog density, first, arbitrary 20 points were selected from a new blank sheet, and the measurement was performed using a Macbeth reflection densitometer (RD-918), and the average value was used as the reference density of the blank sheet. Next, for the white paper printed immediately after the output of the solid black image print, the reflection density at 20 points arbitrarily selected in the same manner as described above is measured, the average value is calculated, and the reference density of the white paper is calculated from this average value. The calculated value was taken as the fog density. Evaluation was performed based on the following criteria, and a fog density of 0.010 or less was accepted.

A: The fog density is less than 0.003. A: The fog density is 0.003 or more and 0.006 or less. Δ: The fog density is larger than 0.006 and 0.010 or less. X: The fog density is larger than 0.010.

<Charge amount stability>
Charge amount stability is to output 6000 sheets of A4 size print image with a pixel rate of 5% continuously in a low temperature and low humidity environment and a high temperature and high humidity environment, respectively, and measure the charge amount before and after continuous printing. Evaluation was performed. The amount of charge was measured by using a toner present on the developing roller with a suction type small charge measuring device “Model 210HS 2A 1-component unit (manufactured by Trek Japan)”. The difference in charge amount between the high-temperature and high-humidity environment and the low-temperature and low-humidity environment was 5 μC / g or less.

<Toner transportability>
As an evaluation of toner transportability on the developing roller, a halftone image of 50% (a halftone image having a density of 50% with respect to the solid image density) is output after 5000 continuous prints are performed. The image density unevenness in the image was visually observed. Evaluation was performed based on the following criteria, and those with ○ and △ were considered acceptable.

○: A halftone image with good graininess is obtained and unevenness is not confirmed. Δ: Some unevenness is observed on the halftone image, but it is judged that there is no practical problem. It appeared.

<Toner sticking occurrence>
The occurrence of toner fixation was evaluated from the image quality of the output print. At the end of the above-described continuous printing of 5000 sheets, a printed matter in which a halftone image was output on the entire surface of the A4 size was prepared, and white streaks in the halftone image were visually observed. Evaluation was performed based on the following criteria, and ◎, ○, and Δ were regarded as acceptable.

◎: No white streak was observed on the halftone image. ○: The density was slightly reduced on the halftone image, but it was not a streak and it was determined that there was no problem. Δ: Some white streaks were observed on the halftone image, but it was determined that there was no practical problem. ×: A clear white streak was confirmed on the halftone image, and it was determined that it was not usable.

  The above results are shown in Table 3.

  As shown in Table 3, in Examples 1 to 15 having the constitutional requirements of the present invention, the results satisfying the regulations for all the evaluation items were obtained. In other words, in each of Examples 1 to 13 that satisfy the structural requirements of the present invention, good charging and toner conveyance can be performed even when a developing roller having a narrow nip width is used, and toner sticking does not occur. It was confirmed that the toner was not damaged by the stress. Further, Example 13 uses the developing roller 2 having a smooth surface shape that makes it relatively difficult to hold the toner. However, good charging performance and toner transportability are exhibited, and toner sticking is also observed. It was confirmed that there was no risk of toner damage.

  On the other hand, Comparative Examples 1 and 5 to 7 using a toner to which a titanic acid compound containing no iron atom is added may be combined with the developing roller 1 that has the best toner retention on the developing roller surface. The charging performance could not be obtained. Further, in Comparative Examples 1 to 7, since toner sticking remarkably appears as a whole, toner breakage occurred during image management.

1 is a schematic diagram illustrating an example of a non-magnetic one-component developing type image forming apparatus. 2 is a cross-sectional view of a developing device that can be used in the image forming method according to the present invention. It is the schematic which shows an example of the developing roller used for this invention. It is a block diagram explaining the measuring method of the volume resistivity of a developing roller. FIG. 3 is a schematic diagram illustrating a core-shell structure type toner.

Explanation of symbols

10 Development roller (hard roller)
11 Shaft 12 Resin layer 121 Intermediate layer 122 Surface layer 20 Developing device (toner cartridge)
24 blade (toner layer regulating member)

Claims (4)

An image forming method comprising a step of supplying a toner carried on a developing roller having no elastic layer to a photosensitive drum and developing an electrostatic latent image formed on the photosensitive drum,
The toner is obtained by adding at least a titanic acid compound to the particle surface containing at least a resin and a colorant.
An image forming method, wherein the titanic acid compound contains 100 ppm to 1000 ppm of iron. The image forming method according to claim 1, wherein the titanic acid compound has a number-based average particle diameter of 50 nm or more and 2000 nm or less. The image forming method according to claim 1, wherein the titanate compound is calcium titanate or magnesium titanate. 4. The toner according to claim 1, wherein the toner has at least one temperature characteristic of a softening point temperature of 121 ° C. or lower and a glass transition temperature of 55 ° C. or lower. The image forming method described.

Images