JP2009192677A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which initial image quality can be maintained, even in a high-speed output. <P>SOLUTION: The image forming method includes at least: a charging step of charging an electrostatic latent image carrier; an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier; a developing step of developing the electrostatic latent image with a developer on a developer carrier to form a toner image; and a transferring step of transferring the toner image onto a transfer material via, or without an intermediate transfer body; and a simultaneous developing and recovering step of recovering the toner remaining on the electrostatic latent image carrier after the transferring step, back to the developer carrier. The method includes a charging assistant step of charging the toner remaining on the electrostatic latent image carrier by the use of at least one charging assistant member, disposed at a farther downstream position than the transfer section in the transferring step, with respect to the rotation direction of the electrostatic latent image carrier, and at a farther upstream position than the charging section in the charging step. The developer includes a toner comprising at least toner particles containing at least a binder resin, a colorant, and wax, and titanium oxide fine powder, and a magnetic carrier. The toner includes a toner surface tension constant in the range of 1.6×10<SP>-3</SP>(N/m) to 1.0×10<SP>-1</SP>(N/m) in a 45 vol% methanol aqueous solution, as measured by capillary suction time method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a toner in electrophotography, electrostatic recording, electrostatic printing, a toner jet method, and the like.
The present invention also relates to an electrostatic developing carrier in which an electrostatic latent image formed on an electrostatic developing carrier such as an electrophotographic photosensitive member or an electrostatic recording derivative is developed with a developer. At the same time as forming a toner image on the surface, a simultaneous development recovery step for recovering toner remaining on the electrostatic development carrier after transfer, and transferring the toner image on the electrostatic development carrier to an intermediate transfer member or transfer material The present invention relates to an image forming method including at least a transfer step.

Conventionally, in an electrophotographic system, an electrostatic charge latent image carrier generally made of a photoconductive substance is charged by various means, and further exposed to form an electrostatic latent image on the surface of the electrostatic latent image carrier. Next, the electrostatic latent image is developed with toner to form a toner image, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat, pressure, and heat and pressure, and a copy is made. Or to obtain a print.
In recent years, specifications such as small size, light weight, and low power consumption while achieving high definition and high image quality have been required to be configured with simpler elements. In addition, an image forming method capable of maintaining stable developability is desired.

  As such an image forming method, there has been proposed a cleanerless system in which toner remaining on the electrostatic development carrier after the transfer process is collected on the developer carrier and simultaneously collected and reused. (Patent Documents 1 and 2). Since this method does not use a cleaning unit, it achieves ecology by making the device compact and eliminating waste toner. However, Patent Documents 1 and 2 do not mention the characteristics and physical properties of the toner. Also, the description of the configuration assuming the use of toner that achieves low power consumption is not allowed. In addition, when a cleanerless system is used for continuous output, there remains a problem that the toner in the developing device is likely to be non-uniformly charged and image defects are likely to occur.

  In view of this, a proposal has been made that includes a charging auxiliary member that charges the toner before the remaining toner is collected (Patent Document 3). However, when a large number of images (image area 50%) used in photographs and POD are printed in a high-temperature and high-humidity environment, a large amount of toner adheres to the auxiliary charging member, so that the image is output from the middle of output. Issues such as a decrease in concentration remain.

Japanese Patent Laid-Open No. 5-53482 JP-A-10-307456 Japanese Patent No. 3083907

The present invention solves the above-mentioned problems of the prior art.
That is, an object of the present invention is to achieve low power consumption, print a large number of images in a large area, and to cope with high speed in an image forming method having at least a simultaneous development recovery step and a charging assist step. Another object of the present invention is to provide an image forming method capable of continuously outputting a stable image having no image defect even after long-term use.

As a result of intensive studies, the inventors have made a charging step for charging an electrostatic latent image carrier, and an electrostatic latent image forming step for forming an electrostatic latent image on the charged electrostatic latent image carrier. A developing process for developing the electrostatic latent image with a developer on a developer carrying member to form a toner image, and a transfer for transferring the toner image to a transfer material with or without an intermediate transfer member. And an image forming method including at least a simultaneous development recovery step of recovering the toner remaining on the electrostatic latent image carrier after the transfer step onto the developer carrier.
With respect to the rotation direction of the electrostatic latent image carrier, the one or more auxiliary charging members are disposed downstream of the transfer unit in the transfer step and upstream of the charging unit of the charging step. A charge assisting step of charging the toner remaining on the electrostatic latent image carrier,
The developer has toner particles containing at least a binder resin, a colorant and a wax, a toner having at least titanium oxide fine powder, and a magnetic carrier.
The present inventors have found that the above-mentioned requirement can be satisfied by adjusting the toner surface tension index with respect to a 45 volume% methanol aqueous solution measured by the capillary suction time method of the toner to a predetermined numerical range, and have reached the present invention.

That is, the present invention is as follows.
(1) a charging step of charging the electrostatic latent image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, and the electrostatic latent image as a developer Developing with a developer on the carrier to form a toner image, a transfer step for transferring the toner image to a transfer material with or without an intermediate transfer member, and the static after the transfer step In the image forming method including at least a development simultaneous recovery step of recovering the toner remaining on the electrostatic latent image carrier on the developer carrier, the transfer in the transfer step is performed with respect to the rotation direction of the electrostatic latent image carrier. A charging auxiliary step of charging the toner remaining on the electrostatic latent image carrier by one or more charging auxiliary members installed downstream of the charging unit and upstream of the charging unit of the charging step. Have
The developer has toner particles containing at least a binder resin, a colorant and a wax, a toner having at least titanium oxide fine powder, and a magnetic carrier.
The toner has a toner surface tension index of 45 × 10 ⁻³ (kN / m) or more and 1.0 which is measured by a capillary suction time method and calculated by the following formula (1). An image forming method, wherein the image forming method is 10 × 10 ⁻¹ (kN / m) or less.
Toner surface tension index = P _α / (A × B × 10 ⁶ ) (N / m) (1)
P _α : Capillary pressure of toner with respect to 45% by volume methanol aqueous solution (N / m ² )
A: Specific surface area of toner (m ² / g)
B: True density of toner (g / cm ³ )

(2) Furthermore, the fluorescent X-ray intensity of titanium obtained by measuring the toner by fluorescent X-ray analysis is Xa, and the toner obtained by separating the magnetic carrier from the developer is analyzed by fluorescent X-ray analysis. The ratio Xb / Xa of Xb to Xa is 0.80 or more and 1.00 or less, when the fluorescent X-ray intensity of titanium obtained by measurement is Xb. (1) Image forming method.

(3) Further, the circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is a circularity range of 0.200 to 1.000. (1) or (2), wherein the average circularity of the toner having an equivalent circle diameter of 2.00 μm or more and 200.00 μm or less analyzed by dividing into 800 is 0.940 or more and 0.980 or less. Image forming method.

(4) Further, the charging auxiliary member includes a first charging auxiliary member to which an AC bias is applied and a second charging auxiliary member to which a DC bias having the same polarity as the toner in the developer carrying member is applied. (1) to (3), wherein the first auxiliary charging member is located upstream of the second auxiliary charging member with respect to the rotation direction of the electrostatic latent image carrier. The image forming method according to any one of the above.

(5) The image forming method according to any one of (1) to (4), wherein at least one of the auxiliary charging members has a rotating brush shape.

  According to a preferred aspect of the present invention, in a cleaner-less system that achieves ecology, even if a high-area image under high temperature and high humidity and a low-area image under normal temperature and low humidity are output at high speed and continuously, In addition, the initial state of a halftone image required for a high-quality printer can be provided stably over a long period of time.

The present invention is described in detail below.
The present invention includes a charging step of charging an electrostatic latent image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, and developing the electrostatic latent image. A development step of developing with a developer on the agent carrier to form a toner image, a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer member, and the post-transfer step In the image forming method having at least a development simultaneous recovery step of recovering the toner remaining on the electrostatic latent image carrier on the developer carrier,
With respect to the rotation direction of the electrostatic latent image carrier, the one or more auxiliary charging members are disposed downstream of the transfer unit in the transfer step and upstream of the charging unit of the charging step. A charge assisting step of charging the toner remaining on the electrostatic latent image carrier,
The developer has toner particles containing at least a binder resin, a colorant and a wax, a toner having at least titanium oxide fine powder, and a magnetic carrier.
The toner has a toner surface tension index of 45 × 10 ⁻³ (kN / m) or more and 1.0 which is measured by a capillary suction time method and calculated by the following formula (1). It is an image forming method characterized by being 10 × 10 ⁻¹ (kN / m) or less. Toner surface tension index = P _α / (A × B × 10 ⁶ ) (N / m) (1)
P _α : Capillary pressure of toner with respect to 45% by volume methanol aqueous solution (N / m ² )
A: Specific surface area of toner (m ² / g)
B: True density of toner (g / cm ³ )

  First, the image forming method of the present invention is one installed at a position downstream of the transfer section in the transfer process and upstream of the charging section of the charging process with respect to the rotation direction of the electrostatic latent image carrier. The charge assisting step of charging the toner remaining on the electrostatic latent image carrier by the above charge assisting member is provided.

  In the current electrophotographic method, there is a demand for a method that is more environmentally friendly with higher speed and higher image quality. And it is required to make as little waste as possible, and it is important to reduce waste toner. Most of the waste toner is toner remaining on the electrostatic latent image carrier after transfer, and is collected through the cleaning member. Therefore, a so-called cleaner-less system in which the cleaning member is not brought into contact with the electrostatic latent image carrier is desirable from the environmental viewpoint. However, in the cleaner system, if untransferred toner remains on the electrostatic latent image carrier, an image defect occurs in continuous image formation. Therefore, in order to provide high speed, high image quality, and environmental friendliness, it is important to eliminate as much as possible the adverse effects that the transfer residual toner remains on the electrostatic latent image carrier. In view of this, the present inventor controls the charging of the toner remaining on the electrostatic latent image carrier by including a charging assisting process in which a charging assisting member is disposed at a position downstream of the transfer unit and upstream of the charging unit. It was found that the toner (transfer residual toner) remaining on the electrostatic latent image carrier can be efficiently returned to the developer carrier.

  The charging auxiliary member includes a first charging auxiliary member to which an AC bias is applied and a second charging auxiliary member to which a DC bias having the same polarity as the toner in the developer carrying member is applied. The first auxiliary charging member is preferably disposed upstream of the second auxiliary charging member with respect to the rotation direction of the electrostatic latent image carrier. The first charging auxiliary member is applied with at least an alternating current bias, and aims to alleviate charging of the transfer residual toner remaining on the electrostatic latent image carrier after the transfer process. Next, the second charging auxiliary member is applied with a DC bias having the same polarity as the toner present on the developer carrier, and when the transfer residual toner moves to the developer carrier, the developer carrier It is easy to be collected.

Further, the shape of the auxiliary charging member can be a known shape, and may be a shape of a rotating brush having a circular cross section (see FIG. 1), such as a deck brush shape, Although not particularly limited, it is possible to use a deck brush shape for the first charging auxiliary member and a rotating brush shape for the second charging auxiliary member in order to control charging of the residual toner. preferable.
As a function of the first charging auxiliary member, it is required to sufficiently relax the charging of the transfer residual toner. For this reason, it is considered that the toner can be once held on the auxiliary charging member by the deck brush shape, and the AC bias can be applied to the untransferred toner.
As a function of the second auxiliary charging member, a DC bias having the same polarity as that of the toner in the developer carrier is applied to the transfer residual toner whose charge is relaxed so that it can be easily collected on the developer carrier, and at the same time, the transfer residual toner Is uniformly dispersed on the electrostatic latent image carrier. Since the transfer residual toner is uniformly dispersed on the electrostatic latent image carrier, charging member contamination is also suppressed, and the toner can be efficiently collected by the developer carrier. Further, since the brush is rotating due to the shape of the rotating brush, it is difficult for toner to adhere to the brush, and stable performance can be exhibited over a long period of time.

The structure of the charging auxiliary member is preferably a brush-shaped member made of conductive fibers, and the fineness of the fibers forming the brush shape is 1.0 d (denier) or more and 10.0 d (denier) or less. The density of the brush is preferably 70 KF / inch ² or more and 500 KF / inch ² or less. Examples of the fiber used include nylon, rayon, and acrylic, but are not particularly limited.

Next, the toner used in the present invention will be described.
The toner used in the present invention is a toner having at least toner particles containing at least a binder resin, a colorant and a wax and fine titanium oxide powder, and is characterized by containing fine titanium oxide powder. The purpose of the fine titanium oxide powder is to make it difficult for transfer residual toner to adhere to the auxiliary charging member. In particular, it has been found that toner having a small particle size tends to adhere to the charging auxiliary member. Further, the fine titanium oxide powder is necessary for ensuring the fluidity of the toner, and it is more preferable that the fine titanium oxide powder be uniformly present on the surface of the toner having a small particle diameter. Therefore, it is preferable to perform multi-stage external addition when adding titanium oxide fine powder to toner particles. For example, the external additive having at least titanium oxide fine powder is externally added in the first stage, and the other external additives are externally added in the second stage, whereby the effects of the present invention can be effectively expressed.

  When the titanium oxide fine powder is not uniformly present on the surface of the toner having a small particle diameter, the toner accumulates on the auxiliary charging member, and the function of relaxing the charging of the toner tends not to be exhibited sufficiently. Further, the toner accumulated on the auxiliary charging member is peeled off, so that an image defect tends to occur. Note that mapping by fluorescent X-ray analysis that can be performed simultaneously with SEM observation is effective as a means for confirming the presence of fine titanium oxide powder on the surface of a toner having a small particle diameter.

Next, the presence state of fine titanium oxide powder in the toner will be described.
In the toner used in the present invention, the fluorescent X-ray intensity of titanium obtained by measurement by fluorescent X-ray analysis is Xa, and the toner obtained by separating the magnetic carrier from the developer is analyzed by fluorescent X-ray analysis. When the fluorescent X-ray intensity of titanium obtained by measurement is Xb, the ratio of Xb to Xa (Xb / Xa) is preferably 0.80 or more and 1.00 or less. More preferably, it is 0.85 or more and 1.00 or less.

The toner used in the present invention contains fine titanium oxide powder. This obtains an effect such as improving the fluidity of the toner by the fine powder of titanium oxide, such as preventing the toner from adhering to the auxiliary charging member as described above. However, when continuous printing is performed, the fine powder of titanium oxide in the toner adheres to the surface of the magnetic carrier and decreases the charge amount of the developer, which is a main cause of fog deterioration. However, the ratio (Xb / Xa) of the fluorescent X-ray intensity (Xb) of titanium in the toner obtained by separating the magnetic carrier from the developer to the fluorescent X-ray intensity (Xa) of titanium contained in the toner is When it is 0.80 or more and 1.00 or less, even if continuous printing is performed, adhesion of the titanium oxide fine powder to the magnetic carrier can be suppressed, and stable image output is enabled.
When the ratio of Xb to Xa (Xb / Xa) is less than 0.80, as described above, fine powder of titanium oxide adheres to the surface of the magnetic carrier, and the charge amount of the developer decreases. When a large number of images with a high image area ratio (image area ratio 50%) were printed in a high-temperature and high-humidity (30 ° C./80% RH) environment, the occurrence of fogging tended to be significant.

The method for separating the magnetic carrier from the developer is performed as follows.
Separation is performed using a charge separation type charge measuring device manufactured by Etowas Co., Ltd. By using the above measuring device, titanium oxide in the toner can be effectively separated without leaving any excess. When separating the toner and the magnetic carrier, 1.5 g of developer was used at a time. When a developer is set on the sleeve of FIG. 2 and a magnet (1000 gauss) inside the sleeve is rotated at 2000 rpm for 1 minute while applying a voltage of −4 kV, the inside of the cylinder (stainless steel) of FIG. Only the toner flies and only the carrier remains on the sleeve. By collecting the toner adhering to the inside of the cylinder, the toner can be effectively recovered from the developer.

In this state where the magnetic carrier is separated from the developer, the fluorescent X-ray intensity (Xb) of titanium in the toner obtained by separating the magnetic carrier from the developer is the fluorescent X-ray of titanium contained in the toner. The ratio (Xb / Xa) to the strength (Xa) needs to be 0.80 or more and 1.00 or less.
The ratio (Xb / Xa) is determined by adjusting the surface tension index of the toner, which will be described later, or by externally adding the titanium oxide fine powder to the toner particles in a multistage process. The eye can be adjusted to the above range by externally adding at least titanium oxide.

  The titanium oxide fine powder that can be used in the present invention is not particularly limited, but the crystal form of the titanium oxide fine powder may be either a rutile or anatase type, and the number average particle diameter is 15 nm or more and 100 nm or less. preferable. As a surface treatment agent for titanium oxide fine powder, known silane coupling agents, fluorine-containing silane coupling agents, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents such as silane compounds, silane compounds, Silicone oil, silicone varnish, etc. can be used. When the number average particle diameter of the titanium oxide fine powder exceeds 100 nm, it tends to be separated from the toner in the developing device, and the effect of imparting fluidity tends to decrease.

  The addition amount of the titanium oxide fine powder is 5 parts by mass or more and 15 parts by mass or less, preferably 5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles.

Next, the surface tension index of the toner used in the present invention will be described.
The toner used in the present invention has a surface tension index of the toner,
It is characterized by being 1.6 × 10 ⁻³ (N / m) or more and 1.0 × 10 ⁻¹ (N / m) or less. The toner surface tension index (N / m) refers to the capillary pressure measured by the capillary capillary suction time method in a 45% volume methanol aqueous solution as P _α (N / m ² ), and the specific surface area of the toner as A (m ^2). / G), when the true density of the toner is B (g / cm ³ ), it is calculated from the following formula (1).
Toner surface tension constant = P _α / (A × B × 10 ⁶ ) (1)

The toner surface tension index indicates the hydrophobicity of the toner surface and the surface tension of the outermost surface of the toner. The toner surface tension index is 1.6 × 10 ⁻³ (N / m) or more and 1.0 × 10 ^−1.
(N / m) or less, the adhesion between the toners can be maintained at an appropriate value. In a cleaner-less system, an image having a high image area in a high temperature and high humidity (30 ° C./80% RH) environment ( Even when a large number of sheets (image area 50%) are printed, the fog does not deteriorate and an image with no change in density can be output.
When the surface tension index of the toner is greater than 1.0 × 10 ⁻¹ (N / m), the fluidity of the developer deteriorates and the toner tends to adhere to the auxiliary charging member, and as a result, the toner accumulates on the auxiliary charging member. In addition, since the charge of the transfer residual toner cannot be controlled, the charge amount distribution of the developer may be widened and fogging may be deteriorated. Further, when the surface tension index of the toner is less than 1.6 × 10 ⁻³ (N / m), the fluidity of the developer is increased, and the image area is high in a high temperature and high humidity (30 ° C./80% RH) environment. When a large number of images (image area 50%) were printed and no image output was performed for more than 3 days, toner scattering occurred and the inside of the copier could be soiled. More preferably, it is 1.6 × 10 ⁻³ (N / m) or more and 5.0 × 10 ⁻² (N / m) or less. The surface tension index of the toner used in the present invention can be adjusted to the above range by controlling the level of hydrophobic treatment on the toner surface. That is, the amount can be adjusted within the above range by adjusting the amount of wax or applying a hydrophobic treatment with wax to the toner surface.

  The toner particles used in the present invention contain a wax. Preferably, the wax is used in an amount of 0.5 to 30 parts by mass, more preferably 3 to 20 parts by mass per 100 parts by mass of the binder resin, thereby preventing wrapping and a decrease in image density. it can. When the wax content is less than 0.5 parts by mass, the fixing member tends to be wrapped around at the time of fixing. When the wax content is more than 30 parts by mass, the dispersion of the wax in the toner tends to decrease, and the carrier is contaminated by the wax during long-term use, and the image density tends to decrease.

Examples of the wax used in the present invention include the following. Low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymer, hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxide of hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof; Waxes based on fatty acid esters such as carnauba wax, behenic acid behenate wax, and montanic acid ester wax; fatty acid esters such as deoxidized carnauba wax that are partially or fully deoxidized.
Furthermore, the following are mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brandic acid, eleostearic acid and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Saturated alcohols such as sil alcohols; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, montanic acid, and stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Esters with alcohols such as sil alcohols; Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; Methylene bis stearic acid amide, ethylene biscapric acid Saturated fatty acid bisamides such as amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N 'dioleyl adipic acid amide, N, N' dioleyl Unsaturated fatty acid amides such as sebacic acid amides; aromatic bisamides such as m-xylene bis-stearic acid amide, N, N ′ distearyl isophthalic acid amide; calcium stearate, calcium laurate, zinc stearate, magnesium stearate Aliphatic metal salts such as those commonly referred to as metal soaps; waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; fatty acids such as behenic acid monoglycerides Alcohol Partial ester; methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable fats and oils.

As the binder resin for the toner used in the present invention, a known resin can be used. For example, polystyrene, homopolymer of styrene derivatives such as polyvinyltoluene, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic Ethyl acid copolymer, Styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer, Styrene-dimethylaminoethyl acrylate copolymer, Styrene-methyl methacrylate copolymer, Styrene-ethyl methacrylate copolymer Polymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, Styrene-bi Styrene copolymers such as dimethyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl Methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, Aromatic petroleum resins are mentioned. Moreover, the hybrid resin which has a vinyl-type polymer unit and a polyester unit is also mentioned. These resins may be used alone or in combination.
Among these, those preferably used as the binder resin are a hybrid resin and a polyester resin having a vinyl polymer unit and a polyester unit.

  The toner of the present invention preferably has a glass transition temperature (Tg) of 40 ° C. or higher and 90 ° C. or lower, and a softening temperature (Tm) of 80 ° C. or higher and 150 ° C. or lower provides storage stability, low-temperature fixability, and high-temperature offset resistance. It is preferable to achieve both. Further, it is preferable that the surface smoothing treatment with hot air can be efficiently made into a spheroid and can prevent the toner from being united.

  The following are mentioned as a coloring agent used by this invention. In the colorant, the pigment may be used alone, but it is preferable from the viewpoint of the image quality of the full color image that the dye and the pigment are used in combination to improve the sharpness.

  Examples of the black colorant include carbon black; a magnetic material; a black colorant prepared using a yellow colorant, a magenta colorant, and a cyan colorant.

Examples of the color pigment for magenta toner include the following.
Examples include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.
Specifically, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, 269; I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35 are mentioned.
Examples of the magenta toner dye include the following. C. I solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. I. Disper thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, C.I. I. Basic dyes such as basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Examples of the color pigment for cyan toner include the following.
C. I. Pigment Blue 1, 2, 3, 7, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66; I. Bat Blue 6, C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyls are substituted on the phthalocyanine skeleton.

Examples of the color pigment for yellow include the following.
Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal compounds, methine compounds, allylamide compounds. Specifically, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 180, 181, 185, 191; I. Bat yellow 1, 3, and 20 are mentioned. In addition, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6 and Solvent Yellow 162 can also be used.
The amount of the colorant used is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, with respect to 100 parts by mass of the binder resin. Most preferably, it is 3 to 15 mass parts.

In the toner of the present invention, a known charge control agent can be used in order to stabilize the charging property. The charge control agent varies depending on the type of charge control agent and the physical properties of other toner constituent materials, but is preferably contained in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the resin in the toner. More preferably, the content is 1 part by mass or more and 5 parts by mass or less. As such a charge control agent, there are known one that controls the toner to be negatively charged and one that controls the toner to be positively charged. The above can be used. The charge control agent may be added internally or externally to the toner.
Examples of the negatively chargeable charge control agent include salicylic acid metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, An example is calix arene.
On the other hand, examples of the positively chargeable charge control agent include quaternary ammonium salts, polymer compounds having a quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds.
In particular, the charge control agent is preferably an aromatic metal carboxylic acid compound that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount.

The developer used in the present invention includes the toner and the magnetic carrier. Examples of the magnetic carrier include oxidized iron powder with oxidized or unoxidized surface; metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, alloy particles thereof or oxidized Magnetic particles such as ferrite; a magnetic material containing a magnetic material; a magnetic material-dispersed resin carrier (so-called resin carrier) containing a magnetic material and a binder resin that holds the magnetic material in a dispersed state;

  When the toner of the present invention is used as a two-component developer, the toner / carrier mixing ratio is 2% by mass or more and 15% by mass or less, preferably 4% by mass or more and 13% by mass as the toner concentration in the developer. It is as follows. If the toner concentration is less than 2% by mass, the image density tends to decrease, and if it exceeds 15% by mass, fogging or in-machine scattering tends to occur.

Further, the toner used in the present invention has a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) of 0.200 or more and 1.000. The average circularity of the toner having an equivalent circle diameter of 2.00 μm or more and 200.00 μm or less analyzed in 800 divided into the following circularity ranges is preferably 0.940 or more and 0.980 or less. More preferably, it is 0.950 or more and 0.980 or less, More preferably, it is 0.954 or more and 0.980 or less.
By setting the average circularity of the toner within this range, the toner surface tension index is 1.6 × 10 ⁻³ (N / m) or more and 1.0 × 10 ⁻¹ or less (N / m). Even in the range, since the contact area between the toner and the charging auxiliary member or the electrostatic latent image carrier is small, the toner is more easily separated from the charging auxiliary member, and the transfer residual toner can easily move to the developer carrier, Further, high transferability can be achieved.

The average circularity in the present invention is the circularity of particles measured by a flow type particle image measuring apparatus having a field of view of 512 pixels × 512 pixels and a resolution of 0.37 μm × 0.37 μm per pixel. This is based on a circularity distribution which is analyzed by limiting the analysis particle size to a circle equivalent diameter of 2.00 μm or more and 200.0 μm or less by distributing the degree range of 0.2 to 1.0 to 800 divided channels. When the average circularity of the toner is less than 0.940, although it depends on the characteristics of the transfer member, generally, the contact area between the toners becomes large and the transferability tends to be lowered. As a result, image defects such as fogging tend to occur.
The average circularity of the toner used in the present invention can be adjusted to the above range by subjecting the toner particles to a surface smoothing treatment. The toner particles can be subjected to a surface smoothing treatment by, for example, heat or mechanical impact force. As the surface smoothing treatment, it is more preferable to perform a mechanical surface smoothing treatment.

  Next, a procedure for producing the toner used in the present invention will be described. As a method for producing the toner used in the present invention, known methods such as a pulverization method, a suspension polymerization method, and an emulsion polymerization method can be used. Here, the pulverization method will be described as an example, but the present invention is not limited to this. That is, the toner used in the present invention is obtained by melt-kneading a binder resin, a colorant, a wax, and an arbitrary material, cooling and pulverizing the pulverized product, and spheroidizing the surface as necessary. It is possible to manufacture by performing treatment and classification treatment, and mixing this with an external additive.

First, in the raw material mixing step, at least a binder resin, a colorant, and a wax are weighed and mixed and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.
Further, the mixed toner raw materials are melt-kneaded to melt the resins and disperse the colorant and the like therein. In the melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to the advantage of being capable of continuous production. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Kay C.K. The Furthermore, the colored resin composition obtained by melt-kneading the toner raw material is rolled by a two-roll roll after melt-kneading, and then cooled through a cooling step of cooling by water cooling or the like.
In general, the cooled colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization process, first, it is roughly crushed with a crusher, hammer mill, feather mill, etc., and further pulverized with a turbo mill manufactured by Turbo Industry, a kryptron system manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nissin Engineering Co., Ltd., etc. Get a crushed product. After that, if necessary, classification is performed using a classifier such as an inertia class elbow jet (manufactured by Nippon Steel Mining Co., Ltd.) or a centrifugal classifier turboplex (manufactured by Hosokawa Micron Co., Ltd.) to obtain a classified product. .
Thereafter, if necessary, surface treatment modification and spheronization may be further performed using, for example, a hybridization system manufactured by Nara Machinery Co., Ltd., a faculty manufactured by Hosokawa Micron, or a mechano-fusion system manufactured by Hosokawa Micron. In such a case, a sieving machine such as a wind-type sieve high voltor (manufactured by Toyo Hitec Co., Ltd.) may be used as necessary. Furthermore, as a method of externally adding the titanium oxide fine powder, a high-speed stirrer that gives a shearing force to the powder such as a Henschel mixer or a super mixer is blended with a predetermined amount of classified toner and various known external additives. A method of stirring and mixing is used as an external additive. The external addition can be performed in two stages.

Next, the image forming method of the present invention will be described.
<Image forming method>
An example of an image forming apparatus using the image forming method of the present invention is shown in FIG. In FIG. 3, the photosensitive member 1 as an electrostatic latent image carrier rotates in the direction of the arrow in the figure. The photosensitive member 1 is charged by a charging device 2 as a charging unit, and a laser beam is projected onto the charged surface of the photosensitive member 1 by an exposure device 3 as an electrostatic latent image forming unit to form an electrostatic latent image. Thereafter, the electrostatic latent image is visualized as a toner image by the developing device 4 that is a developing unit, and is transferred to the intermediate transfer body 6 by the transfer device 5 that is a transfer unit. Further, the image is transferred to a transfer material P by a transfer device 7 as a transfer means, and the transfer material P is heated and fixed by a fixing device 8 as a fixing means and is output as an image. In this transfer unit, the transfer residual toner that is not transferred and remains on the surface of the photosensitive member 1 gives an electrostatic polarity to the transfer residual toner while applying a bias by the charging auxiliary member 10 that is a leveling unit. It may be used again for development through the charging means and electrostatic latent image forming means, or may be collected by the developing device.

  The auxiliary charging member in the present invention is shown in FIG. In the present invention, as shown in FIG. 4, the transfer residual toner on the photoconductor 1 is disposed downstream of the transfer device 5 and upstream of the charging device 2 with respect to the rotation direction of the photoconductor 1. Equally, a charging auxiliary member for improving the recovery rate of the transfer residual toner at the time of development is arranged to make the charging polarity of the transfer residual toner uniform. In the present invention, the charging auxiliary member includes a first charging auxiliary member to which an AC bias is applied, and a second charging auxiliary member to which a DC bias having the same polarity as the toner in the developer carrier is applied. It is preferable. The first auxiliary charging member is represented by A in FIG. 4 and applies an AC bias to the transfer residual toner on the photoreceptor 1. As a result, the charge removal function of the transfer residual toner on the photoreceptor 1 is achieved. The second auxiliary charging member is represented by B in FIG. 4 and applies a DC bias having the same polarity as that of the toner in the developer carrying member (minus in the present invention) to the untransferred toner on the photoreceptor 1. As a result, the toner is negatively charged and the recovery rate of the transfer residual toner during development is increased.

In the present invention, it is preferable that at least one of the auxiliary charging members has a rotating brush shape. Due to the rotating brush shape as shown in B in FIG. 4, the untransferred toner adhered on the photoconductor 1 can be dispersed on the photoconductor 1. As a result, the negatively charged toner is efficiently collected on the developer carrying member, so that a more stable image can be provided when continuously outputting high density images. Furthermore, since the brush itself rotates, adhesion of external additives such as toner and fine titanium oxide powder to the brush is suppressed, and the durability is excellent.

Here, each step of the image forming method of the present invention will be described.
<Charging process>
The charging step is not particularly limited as long as it is a means for charging the surface of the electrostatic latent image carrier to charge the electrostatic latent image carrier. As the charging means, a device for charging the electrostatic latent image carrier without contact with the electrostatic latent image carrier, such as a corona charging means, or a conductive roller or blade is used as the electrostatic latent image carrier. A device for charging the electrostatic latent image carrier by contact can be used.

<Electrostatic latent image forming process>
In the electrostatic latent image forming step, a known exposure apparatus can be used as the exposure means. For example, a semiconductor laser or a light emitting diode is used as the light source, and a scanning optical system unit including a polygon mirror, a lens, and a mirror can be used.

  The area where the electrostatic latent image can be formed includes an area in the main scanning direction and an area in the sub scanning direction. The region in the main scanning direction on the electrostatic latent image carrier is a region from a laser beam irradiation start position to a laser beam irradiation end position in a direction parallel to the rotation axis of the electrostatic latent image carrier. The area in the sub-scanning direction on the surface of the electrostatic latent image carrier is the area from the irradiation position of the first main scanning line to the irradiation position of the last main scanning line in one page of image data.

The electrostatic latent image forming process will be specifically described.
First, a laser beam is irradiated from a semiconductor laser as a light source to a rotating polygon mirror. Then, the laser beam periodically deflected and reflected is focused by the scanning lens, and the electrostatic latent image carrier rotating in the sub scanning direction is repeatedly scanned in the main scanning direction orthogonal to the sub scanning direction. Then, the electrostatic latent image is exposed on the electrostatic latent image carrier. In the image forming apparatus using the toner of the present invention, this electrostatic latent image formable area may be changed to a printing mode (edgeless copy) corresponding to the entire area. In marginless copying, the main scanning direction area and / or the sub-scanning direction area of the electrostatic latent image formable area becomes large. This is because when marginless copying is performed, there is no margin larger than the size of the recording material in order to correct and erase the margin caused by a small size error between the image size of the image data and the actual size of the recording material. This is because it needs to be reflected in the copy magnification. When borderless copy is selected, the exposure apparatus sets the image resolution by setting the main scanning pixel clock and polygon mirror rotation period. The main scanning pixel clock is set by a write clock generation circuit. The polygon mirror rotation period is set by a rotation motor control circuit of the polygon mirror. In addition, the exposure apparatus performs main scanning magnification adjustment and sub-scanning magnification adjustment in the bordered printing mode by finely adjusting the settings of the main scanning pixel clock and the polygon rotation period. Based on this, the main scanning magnification adjustment and the sub scanning magnification adjustment for the borderless image in the borderless copy are performed. As described above, the electrostatic latent image formed on the electrostatic latent image carrier in the electrostatic latent image process is visualized as a toner image by the developer in the developing process.

<Development process>
The development step is mainly divided into a one-component contact development method that does not require a carrier and a two-component development method that includes a toner and a carrier. In the present invention, the development step is a two-component development method.
As a two-component development method, a magnetic brush of a two-component developer is formed on a developer carrier (development sleeve) containing a magnet, and the magnetic brush is adjusted to a predetermined layer thickness by a developer layer thickness regulating member. After coating, the film is transported to a developing area facing the electrostatic developing carrier. In the developing region, the electrostatic brush is brought close to or in contact with the surface of the electrostatic latent image carrier while applying a predetermined developing bias between the electrostatic latent image carrier and the developing sleeve. In this method, the latent image is visualized as a toner image.

<Transfer process, transfer body cleaning process>
The transfer process is a method of transferring the toner image on the surface of the electrostatic latent image carrier to the transfer material in a non-contact manner with respect to the electrostatic latent image carrier, such as a corona transfer means, or a transfer member such as a roller or an endless belt. There is a method in which the toner image on the surface of the electrostatic latent image carrier is transferred to a transfer material by bringing the toner into contact with the electrostatic latent image carrier, and any of them can be used. For cleaning the intermediate transfer member, any cleaning device such as blade cleaning, fur brush cleaning, or a combination thereof can be used.

<Fixing process>
The fixing process includes a conventional hard roller type fixing device including a pair of rollers, and a belt fixing device using a light pressure fixing system corresponding to high speed and energy saving of a recent image forming apparatus as shown in FIG. Any fixing device can be used.

<Full-color image forming apparatus>
An example of a full color image forming apparatus using the image forming method of the present invention is shown in FIG. The arrows indicating the arrangement and rotation direction of image forming units such as K, Y, C, and M in the figure are not limited to these. Incidentally, K means black, Y means yellow, C means cyan, and M means magenta. In FIG. 5, the electrophotographic photoreceptors 1K, 1Y, 1C, and 1M, which are electrostatic latent image carriers, rotate in the direction of the arrow in the figure. Each electrophotographic photosensitive member is charged by charging devices 2K, 2Y, 2C, and 2M that are charging means, and an exposure device 3K, 3Y, 3C, which is an electrostatic latent image forming unit, is charged on the surface of each charged electrophotographic photosensitive member. A laser beam is projected by 3M to form an electrostatic latent image. Thereafter, the electrostatic latent images are visualized as toner images by developing devices 4K, 4Y, 4C, and 4M that are developing means, and transferred to the intermediate transfer body 6 by transfer devices 5K, 5Y, 5C, and 5M that are transfer means. Is done. Further, the image is transferred to a transfer material P by a transfer device 7 as a transfer means, and the transfer material P is heated and fixed by a fixing device 8 as a fixing means and is output as an image. A transfer belt cleaning member 11 collects untransferred toner, carrier, and the like.

The measurement method according to the present invention will be described below.
<Specific surface area of toner>
For the specific surface area of the toner, for example, nitrogen gas is adsorbed on the sample surface using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics), and the specific surface area of the toner is calculated using the BET multipoint method.

<Capillary pressure of toner>
5.5 g of toner is gently put into the measurement cell, and a tapping operation is performed for 1 minute at a tapping speed of 30 times / min using a tapping machine PTM-1 manufactured by Sankyo Piotech. This is set in a measuring device (manufactured by Sankyo Piotech Co., Ltd .: WTMY-232A wet tester) and measured.
Under the following conditions, determine the capillary pressure P _alpha by a constant flow rate method.
Solvent 45% by volume methanol aqueous solution Measurement mode Constant flow method (A2 mode)
Liquid flow rate 2.4ml / min
Cell Y-type measurement cell

<Fluorescent X-ray measurement method>
The toner and the toner from which the magnetic carrier is separated from the developer are each made into pellets having a diameter of 40 mm by a tablet molding machine at a pressure of 159 N / mm ² , and the wavelength dispersion type fluorescent X-ray analyzer RI
Using X3000 (manufactured by Rigaku Denki Kogyo Co., Ltd.), the peak intensity (fluorescent X-ray intensity) of titanium (Ti) is measured and set as Xa and Xb.

<Average circularity of toner>
The average circularity of the toner was measured with a flow type particle image analyzer “FPIA-3000 type” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during calibration.
The measurement principle of the flow-type particle image analyzer “FPIA-3000 type” (manufactured by Sysmex Corporation) is to capture flowing particles as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by the sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle images are picked up by a CCD camera, and the picked-up image is 512 pixels × 512 pixels in one field of view, and image processing is performed at an image processing resolution of 0.37 × 0.37 μm per pixel, and the contour of each particle image Extraction is performed, and the projected area and perimeter of the particle image are measured.
Next, the projected area S and the perimeter L of each particle image are obtained. Using the area S and the peripheral length L, the equivalent circle diameter and the circularity are obtained. The circular equivalent diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity is a value obtained by dividing the circumference of the circle obtained from the circular diameter by the circumference of the projected particle image. Defined and calculated by the following formula.
Circularity C = 2 × (π × S) ^1/2 / L
When the particle image is a perfect circle, the circularity becomes 1.000, and the circularity becomes smaller as the degree of irregularities on the outer periphery of the particle image increases.
After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is distributed to 800 divided channels, and the average value is calculated using the center value of each channel as a representative value to calculate the average circularity.
As a specific measurement method, 0.02 g of a surfactant as a dispersant, preferably sodium dodecylbenzenesulfonate, is added to 20 ml of ion-exchanged water, 0.02 g of a measurement sample is added, an oscillation frequency of 50 kHz, electrical Dispersion treatment was performed for 2 minutes using a desktop ultrasonic cleaner / disperser with an output of 150 W (for example, “VS-150” (manufactured by Velvo Crea Co., Ltd.)) to obtain a dispersion for measurement. Is suitably cooled so that the temperature becomes 10 ° C. or higher and 40 ° C. or lower.
The flow type particle image analyzer equipped with a standard objective lens (10 ×) was used for the measurement, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, 3000 toner particles are measured in the total count mode in the HPF measurement mode, and the binarization threshold at the time of particle analysis is 85%. The analysis particle diameter is limited to a circle equivalent diameter of 2.00 μm to 200.00 μm, and the average circularity of the toner is obtained.
In the measurement, automatic focus adjustment is performed using standard latex particles (for example, Duke Scientific 5200A diluted with ion-exchanged water) before the measurement is started. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.
In the examples of the present application, a flow type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation is used, and the analysis particle diameter is limited to a circle equivalent diameter of 2.00 μm or more and 200.00 μm or less. Measured under the measurement and analysis conditions when the calibration certificate was received.

<Measurement of weight average particle diameter (D4) of toner>
The weight average particle diameter (D4) of the toner is measured using a Coulter Counter TA-II type (manufactured by Coulter), but a Coulter Multisizer (manufactured by Coulter) can also be used.
As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISO
TON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 g of a surfactant, preferably sodium dodecylbenzenesulfonate, is added as a dispersant to 100 ml of the electrolytic aqueous solution, and 5 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion process for 2 minutes with an ultrasonic disperser, and the volume and the number of toners of 2.00 μm or more are measured by using the 100 μm aperture as the aperture by the measuring device. Calculate the distribution. Using the calculation result, the weight average particle diameter (D4) (the median value of each channel is used as the representative value for each channel) is obtained.
As channels, 2.00 to 2.52 μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm; 4.00 to 5.04 μm; 5.04 to 6.35 μm; 6.35 to 8. 00 μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32.00 μm; 13 channels of 32.00-40.30 μm are used.

<Measurement of peak temperature of maximum endothermic peak of wax>
The peak temperature of the maximum endothermic peak of the wax is measured in accordance with ASTM D3418-82 using a differential scanning calorimetry (DSC) apparatus “Q1000” (manufactured by TA Instruments). That is, the temperature detection of the device detection unit uses the melting points of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium.
Specifically, about 5 mg of toner is precisely weighed, put in an aluminum pan, and an empty aluminum pan is used as a reference. Measurement is performed at ° C / min. In the measurement, the temperature is once raised to 200 ° C., subsequently lowered to 30 ° C., and then the temperature is raised again. The peak temperature of the maximum endothermic peak of the DSC curve in the temperature range of 30 to 200 ° C. in the second temperature raising process is defined as the peak temperature of the maximum endothermic peak of the endothermic curve in the DSC measurement of the toner of the present invention.

<Measurement of molecular weight of THF soluble matter of toner by GPC>
The molecular weight distribution of the tetrahydrofuran (THF) soluble part of the toner is measured by gel permeation chromatography (GPC) as follows.
First, the toner is dissolved in THF at room temperature for 24 hours. The obtained solution is filtered through a solvent-resistant membrane filter “Maescho Disc” (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in THF is about 0.8% by mass. Using this sample solution, the molecular weight distribution is measured under the following conditions.
Apparatus: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)
Column: Shodex KF-801, 802, 803, 804, 805,
7 series of 806, 807 (made by Showa Denko)
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 ml
In calculating the molecular weight of the sample, standard polystyrene resin (for example, trade name “TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F— 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", manufactured by Tosoh Corporation) are used.

<Measurement of true density of toner>
The true density of the toner was measured with a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). The conditions are as follows.
Cell SM cell (10ml)
Sample amount about 2.0g

  Hereinafter, the present invention will be described more specifically with reference to specific production examples and examples. However, the present invention is not limited to these examples.

[Production of Resin A (Hybrid Resin)]
As a vinyl polymer, 2.3 mol of styrene, 0.21 mol of 2-ethylhexyl acrylate, 0.14 mol of fumaric acid, 0.03 mol of dimer of α-methylstyrene, and 0.05 mol of dicumyl peroxide were put into a dropping funnel. . Moreover, 7.0 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 0 mol, 3.0 mol of terephthalic acid, 2.0 mol of trimellitic anhydride, 5.0 mol of fumaric acid and 0.8 g of tin hexanoate are placed in a 4-liter 4-necked flask made of glass, a thermometer, a stirring rod, a condenser and nitrogen The introduction tube was installed and placed in a mantle heater. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually increased while stirring, and while stirring at a temperature of 145 ° C., the monomer of the vinyl resin, the crosslinking agent and the polymerization initiator were added from the previous dropping funnel. It was dripped over 5 hours. Subsequently, the temperature was raised to 200 ° C. and reacted for 4.5 hours to obtain a hybrid resin (resin A). As a result of measuring the molecular weight of the resin A by GPC (gel permeation chromatography), the weight average molecular weight Mw was 66000, the number average molecular weight Mn was 4600, and the peak molecular weight Mp was 7600.

[Production of Toner 1]
Resin A 60.0 parts by mass Cyan pigment (Pigment Blue 15: 3) 35.0 parts by mass The above formulation was melt kneaded with a kneader mixer to prepare a cyan master batch. Resin A 86.5 parts by mass Refined paraffin wax (maximum endothermic peak: 72 ° C., Mw = 450, Mn = 32)
5.0 parts by mass · Cyan masterbatch (colorant content 40% by mass) 22.5 parts by mass · Aluminum compound of di-tert-butylsalicylic acid (charge control agent) 1.0 part by mass Was premixed, melt-kneaded with a twin-screw extruder kneader so that the kneaded product temperature was 150 ° C., and after cooling, coarsely pulverized to about 1 to 2 mm using a hammer mill. Further, using a turbo mill (RS rotor / SNB liner) manufactured by Turbo Industry, a finely pulverized product was made to have a weight average particle diameter (D4) of about 5.3 μm. Next, using a faculty manufactured by Hosokawa Micron Co., Ltd., spheronization was performed at the same time as classification to obtain a weight average particle size (D4) of 5.8 μm to obtain cyan particles (toner particles).
Anatase-type titanium oxide fine powder (BET specific surface area = 100 m ² / g, treated with 10% by mass of isobutyltrimethoxysilane) 0.8 part by mass with respect to 100 parts by mass of the cyan particles (toner particles), and sol-gel silica ( 1.5 parts by mass of a BET specific surface area of 24 m ² / g and a number average particle size (D1): 110 nm were added and externally added by a Henschel mixer (first-stage external addition). Thereafter, 1.2 parts by mass of oil-treated silica (BET specific surface area 105 m ² / g, silicone oil 15 mass% treatment) was additionally externally added (two-stage external addition) using a Henschel mixer to obtain toner 1. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 2]
Resin A 60.0 parts by mass Cyan pigment (Pigment Blue 15: 3) 35.0 parts by mass The above formulation was melt kneaded with a kneader mixer to prepare a cyan master batch. Resin A 86.5 parts by mass Refined paraffin wax (maximum endothermic peak: 72 ° C., Mw = 450, Mn = 32)
5.0 parts by mass · Cyan masterbatch (colorant content 40% by mass) 22.5 parts by mass · Aluminum compound of di-tert-butylsalicylic acid (charge control agent) 1.0 part by mass The mixture was premixed, melt-kneaded with a twin-screw extrusion kneader so that the kneaded product temperature was 140 ° C., and after cooling, coarsely pulverized to about 1-2 mm using a hammer mill. Further, using a turbo mill (RS rotor / SNB liner) manufactured by Turbo Industry, a finely pulverized product was made to have a weight average particle diameter (D4) of about 4.9 μm. Next, using a faculty manufactured by Hosokawa Micron Corporation, spheronization was performed at the same time as classification to obtain a weight average particle diameter (D4) of 5.5 μm to obtain cyan particles (toner particles).
An external addition process similar to that for toner 1 was performed on 100 parts by mass of the cyan particles (toner particles), whereby toner 2 was obtained. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 3]
In the production of the toner 1, the amount of paraffin wax was changed to 10.0 parts by mass. Then, after obtaining a finely pulverized product, surface modification was performed by the surface modification apparatus shown in FIG. The conditions for the surface modification were as follows: raw material supply rate = 2.0 kg / hr, hot air discharge temperature = 230 ° C., hot air flow rate = 6 m ³ / min. Cold air temperature E = 5 ° C., cold air flow rate = 4 m ³ / min. , Blower airflow = 20 m ³ / min. Injection air flow rate = 1 m ³ / min. , Diffusion air = 0.4 m ³ / min. Then, surface modification was performed. Next, the finely pulverized product obtained is classified by an air classifier (Elbow Jet Lab EJ-L3, manufactured by Nippon Steel Mining Co., Ltd.) using the Coanda effect, and fine particles and coarse particles are classified and removed at the same time, and the weight average particle Toner particles having a diameter (D4) of 6.0 μm were obtained.
To 100 parts by mass of the cyan particles (toner particles), an external addition process similar to that for the toner 1 was performed to obtain a toner 3. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 4]
In the production of toner 1, the amount of paraffin wax was changed to 18.0 parts by mass. Then, after obtaining a finely pulverized product, surface modification was performed by the surface modification apparatus shown in FIG. The conditions for the surface modification were as follows: raw material supply rate = 2.0 kg / hr, hot air discharge temperature = 240 ° C., hot air flow rate = 6 m ³ / min. Cold air temperature E = 5 ° C., cold air flow rate = 4 m ³ / min. , Blower airflow = 20 m ³ / min. Injection air flow rate = 1 m ³ / min. , Diffusion air = 0.4 m ³ / min. The surface modification was performed. Next, the finely pulverized product obtained is classified by an air classifier (Elbow Jet Lab EJ-L3, manufactured by Nippon Steel Mining Co., Ltd.) using the Coanda effect, and fine particles and coarse particles are classified and removed at the same time, and the weight average particle Toner particles having a diameter (D4) of 6.5 μm were obtained.
To 100 parts by mass of the cyan particles (toner particles), an external addition process similar to that for the toner 1 was performed to obtain a toner 4. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 5]
The following materials, styrene 90.0 parts by mass, n-butyl acrylate 15.0 parts by mass, acrylic acid 3.0 parts by mass, dodecanethiol 6.0 parts by mass, carbon tetrabromide 1.0 part by mass are mixed and dissolved. An organic solution was obtained.
On the other hand, 1.5 parts by mass of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and 2.5 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) , And dissolved in 140 parts by mass of ion-exchanged water in a flask. The organic solution was added to the obtained aqueous solution, dispersed and emulsified, and slowly mixed for 10 minutes.
To the obtained mixture, 10 parts by mass of ion-exchanged water in which 1 part by mass of ammonium persulfate was dissolved was added to perform nitrogen substitution. While stirring the inside of the flask, the content was heated in an oil bath until the temperature reached 70 ° C., and emulsion polymerization was continued as it was for 5 hours to prepare a resin particle dispersion 1. The number average particle diameter of the particles contained in the resin particle dispersion 1 was 0.15 μm.
The following materials, styrene 75.0 parts by mass, n-butyl acrylate 25.0 parts by mass, and acrylic acid 5.0 parts by mass were mixed to obtain an organic solution.
On the other hand, 1.5 parts by mass of a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) and 3 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) An aqueous solution was obtained by dissolving in 150 parts by mass of exchange water in a flask. The organic solution was added to the obtained aqueous solution, dispersed and emulsified, and slowly mixed for 10 minutes.
While mixing, 10 parts by mass of ion-exchanged water in which 0.8 part by mass of ammonium persulfate was further dissolved was added to perform nitrogen substitution. While stirring the inside of the flask, the content was heated in an oil bath until the temperature reached 70 ° C., and emulsion polymerization was continued for 5 hours to prepare a resin particle dispersion 2. The number average particle diameter of the particles contained in the resin particle dispersion 2 was 0.13 μm.
The following materials: Paraffin wax 60.0 parts by mass Anionic surfactant 5.0 parts by mass (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
-200.0 parts by mass of ion-exchanged water were mixed and heated to 97 ° C, and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and further dispersed using a pressure discharge homogenizer. A release agent particle dispersion was prepared. The number average particle diameter of the release agent particles in the dispersion was 0.42 μm.
The following materials and C.I. I. Pigment Blue 15: 3 11.0 parts by mass / Anionic surfactant 2.0 parts by mass (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
-Ion exchange water 78.0 mass parts was disperse-processed using the sand grinder mill, and the colorant dispersion liquid was prepared.
The following materials obtained by processing as described above: 150.0 parts by mass of the resin particle dispersion 1, 210.0 parts by mass of the resin particle dispersion 2, 40.0 parts by mass of the colorant dispersion, and the above-mentioned separation. 70.0 parts by mass of the mold dispersion was charged into a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer and stirred. The mixture was adjusted to pH = 5.4 using 1N potassium hydroxide.
150 parts by mass of a 10% sodium chloride aqueous solution as a flocculant was dropped into the obtained mixed liquid, and the flask was heated to 70 ° C. while stirring in the heating oil bath. While maintaining this temperature, 3 parts by mass of the resin particle dispersion 2 was further added. After holding the obtained solution at 60 ° C. for 1 hour, after adding 3 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel reaction vessel was sealed, The mixture was heated to 90 ° C. with continuous stirring using a magnetic seal and held for 3 hours. After cooling, the reaction product was filtered, and the resulting filtered product was sufficiently washed with ion-exchanged water and then dried to obtain toner particles having a weight average particle diameter (D4) of 6.2 μm.
An external addition process similar to that for toner 1 was performed on 100 parts by mass of the cyan particles (toner particles) to obtain toner 5. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 6]
In the production of toner 1, in the first external addition, oil-treated silica (BET specific surface area of 150 m ² / g, silicone oil of 20% by mass is used instead of anatase-type titanium oxide fine powder.
Treatment) A toner having a weight average particle diameter (D4) of 5.8 μm obtained by using 0.5 part by mass was designated as Toner 6. Table 1 shows various physical properties of the toner and X-ray intensity of titanium oxide.

[Production of Toner 7]
After the amount of paraffin wax was changed to 35.0 parts by mass in the production of the toner 1 to obtain a finely pulverized product, surface modification was performed using a surface modification apparatus shown in FIG. The conditions for the surface modification were as follows: raw material supply rate = 2.0 kg / hr, hot air discharge temperature = 270 ° C., hot air flow rate = 6 m ³ / min. Cold air temperature E = 5 ° C., cold air flow rate = 4 m ³ / min. , Blower airflow = 20 m ³ / min. Injection air flow rate = 1 m ³ / min. , Diffusion air = 0.4 m ³ / min. The surface modification was performed. Next, the finely pulverized product obtained is classified by an air classifier (Elbow Jet Lab EJ-L3, manufactured by Nippon Steel Mining Co., Ltd.) using the Coanda effect, and fine particles and coarse particles are classified and removed at the same time, and the weight average particle Toner particles having a diameter (D4) of 9.8 μm were obtained.
An external addition process similar to that for toner 1 was performed on 100 parts by mass of the cyan particles (toner particles), whereby toner 7 was obtained. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

[Production of Toner 8]
In the production of toner 1, toner particles having a weight average particle diameter (D4) of 8.2 μm were obtained without using paraffin wax.
An external addition process similar to that for toner 1 was performed on 100 parts by mass of the cyan particles (toner particles), whereby toner 8 was obtained. Various physical properties of the toner and (Xb / Xa) are shown in Table 1.

で示される構造を有する一方の末端にエチレン性不飽和基を有する重量平均分子量５，０００のメタクリル酸メチルマクロマー（式中のｎは繰り返し回数を示す）２５質量部、下記式

で示される構造を有するシクロヘキシルをユニットとしてエステル部位を有するメタクリル酸シクロヘキシルモノマー１６７質量部、及びメタクリル酸メチルモノマー１質量部を、還流冷却器、温度計、窒素吸い込み管、及びすり合わせ方式撹拌装置を有する四つ口フラスコに加えた。さらにトルエン９０質量部、メチルエチルケトン１１０質量部、及びアゾビスイソバレロニトリル２．０質量部を加えた。得られた混合物を、窒素気流下７０℃で１０時間保持し、グラフト共重合体溶液（固形分３３質量％）を得た。この溶液のゲルパーミエーションクロマトグラフィ（ＧＰＣ）による重量平均分子量は、４７，０００であった。
得られたグラフト共重合体溶液３０質量部に、疎水化処理することにより得られた疎水性シリカ粒子（個数分布基準の最大ピーク粒径が１００ｎｍ）１質量部、カーボンブラック微粒子（個数分布基準の最大ピーク粒径が３０ｎｍ、比抵抗が１．０×１０^−４Ω・ｃｍ）１質量部、およびトルエン１００質量部を加えて、スーパーアスペックミルによりよく混合して、コート液を得た。
次いで、磁性キャリアコア（ａ）５００質量部を、剪断応力を連続して加えながら撹拌しつつ、上記コート液を徐々に加えた。減圧下（５ｈＰａ）で７０℃に保持して撹拌しながら溶媒を揮発させて、磁性キャリアコア（ａ）表面を樹脂で被覆した。
この樹脂で被覆された磁性キャリアコアを、１００℃で２時間撹拌しながら熱処理した。冷却した後、解砕し、さらに目開き７６μｍの篩で粗粒を除去して、磁性体分散型樹脂キャリアである磁性キャリアＡを得た。磁性キャリアＡの重量平均粒径（Ｄ４）３６．０μｍであった。 [Manufacture of magnetic carrier A]
Magnetite fine particles (number average particle size 260 nm, magnetization strength 65 Am ² / kg, specific resistance 3.2 × 10 ⁵ Ω · cm) and silane coupling agent (3- (2-aminoethylaminopropyl) trimethoxy Silane) (amount of 3.0% by mass with respect to the mass of the magnetite fine particles) was introduced into a container, and the mixture was stirred at a high speed at 100 ° C. or higher in the container to surface-treat the magnetite fine particles.
Next, 10.0 parts by mass of phenol, 10.0 parts by mass of formaldehyde (formaldehyde 36% by mass aqueous solution), 16.0 parts by mass, and 86.0 parts by mass of surface-treated magnetite fine particles were introduced into the flask and mixed well at 40 ° C. . At this time, the amount of dissolved oxygen in the reaction medium was 9.00 g / m ³ . Next, nitrogen gas was introduced into the reaction medium while heating to 65 ° C. The flow rate of the introduced amount of nitrogen gas was 250 cm ³ / min, and gas replacement was performed for 30 minutes.
Thereafter, 4 parts by mass of 28% by mass aqueous ammonia and 8 parts by mass of water were added to the flask. While stirring, the mixture was heated from 65 ° C. to 85 ° C. at an average heating rate of 3 ° C./min. It was kept at 85 ° C. and cured by polymerization reaction for 3 hours.
After the polymerization reaction, the mixture was cooled to 30 ° C. and water was added. The precipitate obtained by removing the supernatant was washed with water and further air-dried. The obtained air-dried product was dried at 60 ° C. under reduced pressure (5 hPa or less) to obtain a spherical magnetic carrier core (a) in which a magnetic material was dispersed. The weight average particle diameter (D4) of the magnetic carrier core (a) was 36 μm.
Then the following formula

25 parts by weight of a methyl methacrylate macromer having a weight average molecular weight of 5,000 having an ethylenically unsaturated group at one end having the structure represented by the formula (where n represents the number of repetitions), the following formula

167 parts by weight of cyclohexyl methacrylate monomer having an ester moiety with cyclohexyl having a structure represented by the following formula and 1 part by weight of methyl methacrylate monomer, having a reflux condenser, a thermometer, a nitrogen suction pipe, and a mixing type stirring device Added to a four-necked flask. Further, 90 parts by mass of toluene, 110 parts by mass of methyl ethyl ketone, and 2.0 parts by mass of azobisisovaleronitrile were added. The obtained mixture was held at 70 ° C. for 10 hours under a nitrogen stream to obtain a graft copolymer solution (solid content: 33% by mass). The weight average molecular weight of this solution by gel permeation chromatography (GPC) was 47,000.
30 parts by mass of the obtained graft copolymer solution is 1 part by mass of hydrophobic silica particles (number distribution standard maximum peak particle size is 100 nm) obtained by hydrophobizing, carbon black fine particles (number distribution standard A coating solution was obtained by adding 1 part by mass of a maximum peak particle size of 30 nm and a specific resistance of 1.0 × 10 ⁻⁴ Ω · cm) and 100 parts by mass of toluene and mixing well with a Super Aspec Mill.
Subsequently, the coating liquid was gradually added while stirring 500 parts by mass of the magnetic carrier core (a) while continuously applying shear stress. The solvent was volatilized while stirring at 70 ° C. under reduced pressure (5 hPa), and the surface of the magnetic carrier core (a) was coated with a resin.
The magnetic carrier core coated with this resin was heat-treated with stirring at 100 ° C. for 2 hours. After cooling, the mixture was crushed and coarse particles were removed with a sieve having an aperture of 76 μm to obtain a magnetic carrier A which is a magnetic material-dispersed resin carrier. The weight average particle diameter (D4) of the magnetic carrier A was 36.0 μm.

[Production of developer]
10 parts by mass of toner 1 and 90 parts by mass of magnetic carrier A were mixed to obtain developer 1.
Similarly, a mixture of toners 2 to 8 and magnetic carrier A was designated as developers 2 to 8, respectively.

[Examples 1 to 7, Comparative Examples 1 to 4]
Evaluation was carried out using a combination of a charging auxiliary member and a developer described in Table 2. The deck brush used in this example is a nylon fiber having a fineness of 6d, a density of 100 KF / inch ² , a length of a hair foot of 5 mm, and carbon black. The rotating brush used was a nylon fiber having carbon black having a fineness of 2d, a density of 400 kF / inch ² , and a pile length of 4 mm. As an evaluation, before and after the endurance test, an endurance test was performed under the following conditions using a Canon full color copier iRC5180 remodeled machine that was modified around the charging auxiliary member and remodeled to high-speed specifications (300 mm / sec). Various evaluations were performed.
Evaluation items and evaluation criteria are shown below. The obtained evaluation results are shown in Table 2.

<Durability Test 1 (Durability Test with Low Density Image)>
Printing environment Temperature 23 ° C / Humidity 5% RH (hereinafter “N / L”)
Paper Color laser copier paper (81.4 g / m ² )
(Canon Marketing Japan Inc.)
Image Number of printed solid images with 1% image area 100,000 sheets

<Durability test 2 (Durability test with high density image)>
Printing environment Temperature 30 ° C / Humidity 80% RH (hereinafter "H / H")
Paper Color laser copier paper (81.4 g / m ² )
(Canon Marketing Japan Inc.)
Image Number of printed solid images with 50% image area 100,000 sheets

<Evaluation of fog>
After the endurance tests 1 and 2, the fog was evaluated in the single color mode using the Canon full color copier iRC5180 remodeling machine. The fog measurement method is as follows. First, the average reflectance Dr (%) of plain paper before image printing is measured by a reflectometer (“REFLECTOMETER MODEL TC-6DS” manufactured by Tokyo Denshoku Co., Ltd.) equipped with an amber filter. On the other hand, a solid white image is drawn on plain paper, and then the reflectance Ds (%) of the solid white image is measured. Using these measured values, fog (Fog [%]) is obtained by the following equation.
Fog [%] = Dr [%] − Ds [%]
(Evaluation criteria)
A: Less than 0.7%, excellent B: 0.7 or more, less than 1.2%, good C: 1.2 or more, less than 1.5%, no practical problem
D: 1.5 or more and less than 2.0%, there are practical problems
E: It is bad at 2.0% or more

<Image density change before and after H / H durability test>
Before the durability test 2, the developing voltage was adjusted so that the amount of toner loaded on the paper was 0.6 mg / cm ² . Under the conditions, a solid image (3 cm × 3 cm) having an image area of 100% was printed with 400 lines. Then, after the durability test 2, the same solid image was printed at the same development voltage as that before the durability test 2. Macbeth Densitometer RD918 type (Macbeth Densitometer RD918manufactured) with an SPI filter
by McBeth Co. ), The image density was measured, and the difference before and after the durability test was determined. The evaluation of the image density change was confirmed in an H / H environment where toner adhesion was severe.
(Evaluation criteria)
A: 0.00 or more and less than 0.05, good B: 0.05 or more and less than 0.10, no practical problem C: 0.10 or more, but less than 0.20, practical problem D: 0.20 or more, bad

<Evaluation method for halftone lines>
A halftone image was output before the durability test. The obtained image was subjected to density measurement with a densitometer X-Rite 500 type, and an average value of 6 points was taken as an image density. Next, after performing durability test 2, the apparatus was adjusted so that the image density was 0.5 or more and 0.7 or less, three A4 images were output, and streaks were visually confirmed.
The halftone streak was evaluated in an H / H environment where toner adhesion was severe.
(Evaluation criteria)
A: Uniform image with no streaks B: Within 1 / sheet no problem in practical use
C: Less than 3 / sheet, practical problem D: 3 or more / bad

(Examples 1 and 5)
In N / L and H / H environments, an image that faithfully reproduces the original without fogging even after endurance was formed. Also, there was no difference in image density before and after the durability, and a high density could be output stably. Also, the level of the halftone image streak was good even before and after the durability test 2.

(Example 2)
Since the second charging auxiliary member is a deck brush, toner adhesion to the brush occurs slightly, and although the image density level and the halftone image level are slightly lowered in the H / H environment, the level is not problematic in practical use. The image was output.

(Example 3)
By removing the second auxiliary charging member, it was not possible to sufficiently control the charge of the transfer residual toner, and although the fog after endurance was slightly reduced, an image having a practically no problem level could be output.

(Comparative Example 1)
By removing the charging auxiliary member, the transfer residual toner adheres to the charging member of the electrostatic latent image carrier, and the image level deteriorates.

Example 4
Although the average circularity of the toner 2 is slightly low and the toner is slightly adhered to the charging auxiliary member, the charge control of the transfer residual toner cannot be sufficiently performed, and the image density level and the halftone image level after the durability test are slightly decreased. An image of a level with no problem in practical use was output.

(Example 6)
Since the toner 4 has a slightly large amount of wax and a large surface tension index, the toner adheres to the auxiliary charging member after endurance in an H / H environment, so that the charge of the transfer residual toner cannot be sufficiently controlled. Although the image level was slightly reduced, an image with a level that was not problematic for practical use could be output.

(Example 7)
Because the surface of the toner 5 is hard or the titanium oxide is slightly transferred from the carrier to the carrier and the value of Xb / Xa is a little low, the toner adheres to the auxiliary charging member after the durability test in the H / H environment. Although the charge control of the transfer residual toner could not be sufficiently performed and the image level after the endurance test was slightly lowered, an image having a practically no problem level could be output.

(Comparative Example 2)
Since the toner 6 does not have titanium oxide added externally, the transfer residual toner fine particles adhered to the charging auxiliary member after the endurance test, thereby lowering the function of the charging auxiliary member and deteriorating the image density level and the halftone image level. I let you.

(Comparative Example 3)
Since the toner 7 has a large amount of wax and a large surface tension index, the function of the auxiliary charging member is deteriorated due to adhesion of fine particles of the transfer residual toner to the auxiliary charging member after the durability test, and the image density level, Degraded halftone image level.

(Comparative Example 4)
Since the toner 8 does not contain wax in the toner, winding occurred at the fixing portion, and image evaluation could not be performed.

It is the schematic which shows an example of a charging auxiliary member. It is the schematic which shows the sleeve periphery of an Etos company electric field separation type | formula charge amount measuring apparatus. It is the figure seen from the side of the Etowa company electrolysis separation type charge amount measuring apparatus. 1 is a schematic diagram illustrating an example of an image forming apparatus. It is the schematic which shows the example around an electrostatic latent image carrier in connection with image formation. 1 is a schematic diagram illustrating an example of a full-color image forming apparatus. It is the schematic which shows an example of a surface modification apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging member 3 of photoconductor Exposure device 4 Developing device 5 Primary transfer roller 6 Intermediate transfer belt 7 Secondary transfer roller 8 Fixing device 10 Charge auxiliary member P Transfer material A Deck brush B Rotating brushes 1K, 1Y, 1C, 1M photoreceptor 2K, 2Y, 2C, 2M charging device 3K, 3Y, 3C, 3M exposure device 4K, 4Y, 4C, 4M developing device 5K, 5Y, 5C, 5M primary transfer roller 11 cleaning unit 21 toner particles 22 auto feeder 23 supply Nozzle 24 Inside surface reformer 25 Hot air inlet 26 Cold air inlet 27 Surface-modified toner particles 28 Cyclone 29 Blower

Claims (5)

A charging step for charging the electrostatic latent image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the charged electrostatic latent image carrier, and the electrostatic latent image on the developer carrier. A developing process for forming a toner image by developing with a developer, a transfer process for transferring the toner image to a transfer material with or without an intermediate transfer member, and the electrostatic latent image after the transfer process In the image forming method having at least a development simultaneous recovery step of recovering the toner remaining on the carrier to the developer carrier,
With respect to the rotation direction of the electrostatic latent image carrier, the one or more auxiliary charging members are disposed downstream of the transfer unit in the transfer step and upstream of the charging unit of the charging step. A charge assisting step of charging the toner remaining on the electrostatic latent image carrier,
The developer has toner particles containing at least a binder resin, a colorant and a wax, a toner having at least titanium oxide fine powder, and a magnetic carrier.
The toner is measured by a capillary suction time method, and the surface tension index of the toner with respect to a 45 volume% methanol aqueous solution calculated by the following formula (1) is:
1.6 × 10 ⁻³ (N / m) or more and 1.0 × 10 ⁻¹ (N / m) or less,
Toner surface tension index = P _α / (A × B × 10 ⁶ ) (N / m) (1)
P _α : Capillary pressure of toner with respect to 45% by volume methanol aqueous solution (N / m ² )
A: Specific surface area of toner (m ² / g)
B: True density of toner (g / cm ³ )
An image forming method characterized by that.   Obtained by measuring the toner obtained by measuring the toner by fluorescent X-ray analysis with Xa as the fluorescent X-ray intensity of titanium, and measuring the toner obtained by separating the magnetic carrier from the developer by fluorescent X-ray analysis. 2. The image formation according to claim 1, wherein the ratio of Xb to Xa (Xb / Xa) is 0.80 or more and 1.00 or less when the fluorescent X-ray intensity of titanium is Xb. Method.   The circularity measured by a flow-type particle image measuring apparatus with an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is divided into 800 circularity ranges from 0.200 to 1.000 and analyzed. 3. The image forming method according to claim 1, wherein an average circularity of the toner having a circle equivalent diameter of 2.00 μm to 200.00 μm is 0.940 to 0.980. 4.   The charging auxiliary member includes a first charging auxiliary member to which an AC bias is applied, and a second charging auxiliary member to which a DC bias having the same polarity as the toner in the developer carrier is applied. 4. The image according to claim 1, wherein the one charging auxiliary member is located upstream of the second charging auxiliary member with respect to the rotation direction of the electrostatic latent image carrier. 5. Forming method.   The image forming method according to claim 1, wherein at least one of the auxiliary charging members has a rotating brush shape.

Images