JPH11282210A - Electrophotographic toner and developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a developer which has stable electrification characteristics in its life by incorporating a toner which contains a linear polyester resin having a specified acid value and specified glass transition temp., a coloring agent and a boron-based complex. SOLUTION: The developer contains a toner which contains at least a linear polyester resin having 5 to 30 KOH mg/g acid value and 45 to 65 deg.C glass transition temp., a coloring agent and a boron-based complex. By mixing the toner to be used with, for example, a carrier comprising magnetic particles coated with an insulating resin, the mixture can be used as a two-component developer. By using the two-component developer, and further by applying an AC electric field between an image holding body and a developing roller, a sharp image can be obtd. A preferable developing method includes a process to form an electrostatic latent image on an image carrying body and a process to form a magnetic brush by using a developer containing a toner and a carrier and to develop the electrostatic latent image by applying an AC electric field between the image carrying body and the developing roller to form a visible image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in an electrophotographic apparatus, an electrostatic recording apparatus, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In an electrophotographic apparatus or an electrostatic recording apparatus, various dry developing methods for visualizing an electrostatic latent image formed on an electrostatic holding member from a photoreceptor or a dielectric have conventionally been used. Proposed. Examples of such a system include a one-component magnetic system, a one-component non-magnetic system, and a two-component system.

[0003] The developer used generally has fluidity and
It is required to have excellent properties such as anti-caking properties, fixing properties, charging properties, and cleaning properties. A full-color copying machine generally uses a two-component system in which a toner is mixed with a resin such as iron powder, ferrite particles, and magnetite particles, or a carrier obtained by coating these with a resin.

Such toners include, for example, black, cyan,
The desired color reproducibility is output using four colors of magenta and yellow. In order to improve color reproducibility, it is useful to use a sharp melt resin that immediately melts the overlapping toner at the time of fixing, eliminates the occurrence of particle shadows, has good transparency, and improves color reproducibility. is there. In particular, when an image is projected on a screen or the like using transmitted light for an OHP or the like, it is important to use such a resin. For this reason, in a full-color copying machine, it is preferable to use a linear polyester as a sharp-melt resin that dissolves at a relatively low temperature and has good transparency.

[0005] This polyester resin has charging characteristics due to the acid value of its carboxyl group. However, when a resin having a low acid value such as a linear polyester proposed in, for example, JP-A-63-163469, is used, the charge characteristics cannot be maintained, and the charge amount is low. Stain of the image, inside of the machine due to toner scattering, and the like occur. On the other hand, when a resin having a high acid value is used, there is a problem that the charge amount becomes high and a sufficient image density cannot be obtained. Furthermore, the charge amount of the polyester resin itself tends to increase with life, and it has been difficult to obtain a stable charge amount.

In order to improve the charging characteristics of the developer, a charge control agent (CCA) can be added to repeatedly stabilize the image formation. The boron-based complex compound has less coloring property as compared with a metal complex containing a trivalent metal such as chromium (III), iron (III), aluminum, manganese, and magnesium which is preferably used as CCA. Although it is considered to be useful for color toners, it was inferior in that the charge stability against life was insufficient.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and is directed to a polyester resin which is a sharp melt resin having a relatively low softening point, and a boron complex compound having excellent transparency. It is an object of the present invention to obtain a developer having a charge characteristic that is stable over its life by using a charge control agent containing as a main component.

[0008]

SUMMARY OF THE INVENTION The present invention firstly comprises the steps of:
A developer comprising a linear polyester resin having an acid value of 30 KOH mg / g and a glass transition point of 45 to 65 ° C., a colorant, and a toner containing at least a boron complex compound.

According to the present invention, there is provided an electrostatic latent image forming step of forming an electrostatic latent image on an image bearing member, and
A visible image is developed using a developer containing a toner containing at least a linear polyester resin having an acid value of KOH mg / g and a glass transition point of 45 to 65 ° C., a colorant, and a boron complex compound. And a visible image forming step of forming.

Third, the present invention provides an electrostatic latent image forming step for forming an electrostatic latent image on an image carrier, and
A magnetic brush is formed using a linear polyester resin having an acid value of 30 KOH mg / g and a glass transition point of 45 to 65 ° C., a colorant, a toner containing at least a boron complex compound, and a developer containing a carrier. And a visible image forming step of developing an electrostatic latent image by applying an alternating electric field between the image carrier and the developing roller to form a visible image. I do.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have made a polyester resin which is a sharp melt resin having a relatively low softening point and good transparency as a binder, and a boron-based resin having excellent transparency as a charge control agent. As a result of examining the charging characteristics of the developer using the complex compound, it was found that good charging characteristics can be obtained when a linear polyester resin having predetermined characteristics is used in combination with the boron-based complex compound. This led to the present invention.

The developer of the present invention has a content of 5 to 30 KOHmg.
/ G and a toner containing a linear polyester resin having a glass transition point of 45 to 65 ° C, a colorant, and a boron-based complex compound.

Further, the developing method of the present invention is a developing method using the above-mentioned developer, wherein an electrostatic latent image forming step of forming an electrostatic latent image on an image carrier, and 5-30KOH
A visible image is formed by developing using a developer containing a toner containing a linear polyester resin having an acid value of mg / g and a glass transition point of 45 to 65 ° C., a colorant, and a boron complex compound. And a visible image forming step.

According to the present invention, the above-mentioned 5 to 30 KOHm
By using a linear polyester resin binder having an acid value of g / g and a glass transition point of 45 to 65 ° C. and a boron-based complex compound charge controlling agent, fluidity, anti-caking properties, fixing properties, charging properties, cleaning properties Thus, a good developer having good developer characteristics such as toner properties and stable charging characteristics over life can be obtained.

Further, when development is performed using such a developer, stable charging characteristics can be obtained over the life, and a high-quality image can be obtained. In particular, when a colorant for a color toner is applied to the developer of the present invention, an image having good color reproducibility can be obtained.

The developer of the present invention can be used as a two-component developer by mixing the toner to be used with, for example, a carrier composed of magnetic particles coated with an insulating resin.

According to the present invention, a clearer image can be obtained by using a two-component developer and further applying an alternating electric field between the image carrier and the developing roller. Such a preferable developing method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an image carrier, and 5 to 30 KO on a developing roller.
A magnetic brush is formed by using a linear polyester resin having an acid value of Hmg / g and a glass transition point of 45 to 65 ° C., a colorant, a toner containing at least a boron-based complex compound, and a developer containing a carrier. And a visible image forming step of developing an electrostatic latent image by applying an alternating electric field between the image carrier and the developing roller to form a visible image.

When an alternating electric field is applied between the image carrier and the developing roller, the developer can reciprocate between the electrostatic latent image and the magnetic brush. Of the developer transferred from the magnetic brush onto the image carrier, the developer supplied to the electrostatic latent image adheres to the image carrier, and the excess developer and the developer that is not sufficiently adhered are: Return to magnetic brush. By repeating this, the developer not adhered to the image carrier can be sufficiently collected on the magnetic brush side, while the developer can be easily resupplied to the electrostatic latent image with insufficient development. As a result, the developer is efficiently supplied to the electrostatic latent image. For this reason, an image with higher quality and a dense solid image can be obtained.

In the developer, 5 to 30 KOHmg /
g is used in combination with a linear polyester resin having an acid value of 45 g and a glass transition point of 45 to 65 ° C., and a boron-based complex compound. The charging characteristics are not easily reduced.

From the above, a clearer and higher quality image can be obtained by using the preferred developing method of the present invention. FIG. 1 is a schematic diagram showing an example of a developing device to which the present invention can be applied.

As shown in FIG. 1, the developing device 14 is provided to face a rotatable latent image holding member (photosensitive drum) 10. The photosensitive drum 10 is rotated in the direction of arrow a by a main motor (not shown). An electrostatic latent image corresponding to image information to be recorded is formed on the surface of the photosensitive drum 10 by a laser beam indicated by an arrow X from a separately provided laser exposure device.

Around the photosensitive drum 10, a charging device 12 for charging the photosensitive drum 10 to a predetermined potential along an arrow a in the direction of rotation thereof, and a photosensitive drum 10 provided by a separately provided laser exposure device. A developing device 14 for developing the electrostatic latent image by supplying toner to the electrostatic latent image formed on the photosensitive drum 10, and a transfer device 16 for transferring the toner image formed on the photosensitive drum 10 to the paper by the developing device 14 A toner removing device 17 for facilitating cleaning of untransferred toner, and a cleaning device 1 for scraping off toner remaining on the surface of the photosensitive drum 10, that is, untransferred toner.
8. A charge removing device 19 for removing charges remaining on the surface of the photosensitive drum 10 is arranged in order. Although the static eliminator 19 is integrated with the housing of the cleaning device 18 in FIG. 1, it may be provided separately. Furthermore, between the developing device 14 and the transfer device 16, a separate static eliminator may be provided to facilitate the transfer of the toner to the paper.

The cleaning device 18 has a drum holder for supporting the photosensitive drum 10 when the photosensitive drum 10 is loaded into the image forming apparatus 1, and is also used as a drum holder.

The charging device 12 includes a corona wire 12a and a grid screen 12b, is connected to a high voltage circuit and a grid bias voltage generator (not shown), and charges the surface of the photosensitive drum 10 to a predetermined surface potential.

The developing device 14 mixes a toner T containing at least a boron compound containing a linear polyester as a main component and a coloring material, and magnetic carrier particles C coated with an insulating resin at a predetermined ratio. A magnetic brush (not shown) is formed on the developer carrier (developing roller) 14a with the developer D, and is brought into contact with the photosensitive drum 10 on which the opposed electrostatic latent image is formed, thereby developing the electrostatic latent image and visualizing it. I do.

The developer D and the developing roller 14a are contained in a housing 14b. At both ends in the longitudinal direction of the developing roller 14a, the distance between the surface of the non-magnetic sleeve forming the outer peripheral surface of the developing roller 14a and the photosensitive layer on the surface of the photosensitive drum 10 is kept constant. A guide roller 14c is provided. As a method of keeping the distance constant, other than the guide roller 14c, a material having a fixed thickness may be bonded or coated, or a material having a fixed thickness may be provided on the end of the photosensitive drum by bonding or coating. Thereby, the surface of the sleeve and the photosensitive drum 10 are
Is always kept constant.

At this time, the distance between the sleeve surface and the photosensitive layer is preferably 0.1 to 1 mm. If the thickness is less than 0.1 mm, the magnetic powder covered with the insulating resin held on the surface of the developing roller is clogged, and the sleeve is easily damaged, which also affects the image. Also, if it exceeds 1 mm,
Since a high voltage needs to be applied as a developing bias, toner is liable to be scattered, causing image stains, and a magnetic powder coated with an insulating resin is formed on a sleeve in a thick layer to form a full-color image. Affect.

The sleeve of the developing roller 14a contains a magnet medium in which a plurality of fixed magnets having S and N poles are arranged at a predetermined angle in the circumferential direction. A predetermined developing bias voltage is applied to the developing roller 14a and the magnetic carrier particles C and the toner T, that is, the developer D in the developing device 14 via a developing bias voltage generating circuit (not shown).

As the predetermined developing bias, a frequency 1 to which a DC voltage of minus 300 to minus 600 V is superimposed is used.
An alternating electric field of 10 kHz and a waveform peak voltage of 0.5 to 3 kV is applied. As a result, a high-quality image was obtained.

The upper limit of the peak voltage of the waveform was optimized from the discharge electric field value of the developing unit, and the lower limit was optimized from the limit value of the toner flight. The same phenomenon as the DC bias occurred regardless of whether the frequency was high or low, resulting in image degradation.

When developing the electrostatic latent image formed on the surface of the photosensitive drum 10, the carrier ears formed on the sleeve along the lines of magnetic force generated from the main pole of the magnet medium of the developing roller 14a. In the developing area where the photosensitive drum 10 and the developing roller 14a face each other, the toner adhered to the photosensitive drum 10 by the image force moves due to the electric field formed by the potential of the electrostatic latent image on the photosensitive drum 10 and the developing bias voltage. Then, the electrostatic latent image is developed.

FIG. 1 shows a copying machine using a single-color developer. However, in a full-color copying machine, a method of arranging a plurality of the above-described developing devices in parallel, a method of arranging a plurality of developing devices around a photosensitive drum, A method of arranging a plurality of developing rollers provided with a toner supply device is used.

The toner used in the developing device will be described in more detail. The main component used in the toner according to the present embodiment has an acid value of 5 to 30 KOHmg.
/ G and a linear polyester resin having a glass transition point of 45 to 65 ° C are used.

Among the monomers constituting the linear polyester in the present invention, alcohol monomers include
For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, Diols, such as 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, bisphenol A alkylene oxide adducts such as polyoxyethylenated bisphenol A, polyoxypropylene bisphenol A, and other dihydric alcohols. it can.

Among these monomers, particularly, a system using a bisphenol A alkylene oxide adduct as a main component monomer showed good results. When a bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point is obtained due to the nature of the bisphenol A skeleton, and blocking resistance is improved. Further, the presence of the alkyl groups on both sides of the bisphenol A skeleton functions as a soft segment in the polymer, and the low-temperature fixability is improved.

Among the monomers constituting the polyester in the present invention, examples of the acid monomer include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and cyclohexanedicarboxylic acid. Acids, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, anhydrides of these acids, alkyl esters, other Divalent carboxylic acids can be mentioned.

The linear polyester used in the present invention must have an acid value of 5 to 30 KOHmg / g. When the acid value is less than 5 KOHmg / g, the chargeability of the resin is deteriorated, the compatibility with the colorant and additives such as the charge control agent is deteriorated, the dispersibility is deteriorated, and the color reproducibility is deteriorated. And adverse effects such as a decrease in chargeability. The acid value is 3
If it exceeds 0 KOH mg / g, the chargeability of the resin itself becomes strong, but the charge control of the toner becomes difficult, for example, the charge amount decreases in a high humidity state, and the charge characteristics in life are not stabilized.

The glass transition point of the linear polyester resin used in the present invention must be 45 to 65 ° C. If the temperature is lower than 45 ° C., blocking occurs during storage of the toner, and a problem of hardening occurs. If the temperature is higher than 65 ° C., a problem occurs in color reproducibility in full-color copying without sharp melting at the time of fixing.

The glass transition point can be measured by a general method, for example, by measuring the energy change of a differential thermal balance.
Incidentally, the linear polyester resin in the present invention can be synthesized by a usual method. Specifically, the reaction temperature (17
(0 to 250 ° C.) and a reaction pressure (5 mmHg to normal pressure), and the reaction may be terminated when the desired physical properties are reached. The boron compound preferably used in the present invention is represented by the general formula (1).

[0040]

Embedded image

(Wherein R ₁ and R ₄ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ represent a substituted or unsubstituted aromatic ring (condensed ring) Xn ⁺ represents a cation, and n is 1
Or 2. As typical examples of the boron compound represented by the general formula (1), boron compounds (1) to (5) are shown below.

[0042]

Embedded image Boron compound (1)

[0043]

Embedded image Boron compound (2)

[0044]

Embedded image Boron compound (3)

[0045]

Embedded image Boron compound (4)

[0046]

Embedded image

As the colorant of the boron compound (5), various pigments and dyes generally used for toner can be used. Examples of the yellow colorant include nitro pigments such as naphthol yellow S, azo pigments such as Hanza Yellow 5G, Hanza Yellow 3G, Hanza Yellow G, Benzidine Yellow GR, Benzidine Yellow G, and Vulcan Fast Yellow 5G, or yellow oxide. Inorganic pigments such as iron and loess; As the dye, for example, C.I. I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I. I. Solvent Yellow 14,
C. I. Solvent Yellow 15, C.I. I. Solvent Yellow 16, C.I. I. Solvent Yellow 19, C.I.
I. And oil-soluble dyes such as Solvent Yellow 21.

The magenta coloring material is, for example, C.I. I. Pigment 122, C.I. I. Quinacridone pigments such as CI Pigment Violet 19, rhodamine 6G
Lake, rhodamine B lake, C.I. I. Rhodamine-based pigments such as C.I. Pigment Red 81; I. Pigment Red 87, C.I. I. Bio Red 1, C.I. I. Thioindigo pigments such as C.I. Pigment Bio Red 38; azo pigments such as Brilliant Carmine 6B and Lysole Rubin GK; I. Solvent Red 49, C.I. I. Solvent Red 19, C.I. I. And oil-soluble dyes such as Solvent Red 52.

The cyan colorant includes, for example, phthalocyanine blue, heliogen blue G, fast sky blue, C.I. I. Pigment Blue 15, C.I.
I. Pigment Blue 16, C.I. I. Pigment Blue 17, C.I. I. Pigment Green 7, C.I. I. Pigment Green 12, C.I. I. Pigment Green 36,
C. I. Pigment Green 37, C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 38; I. Solvent Blue 25, C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 70, C.I.
I. Solvent Blue 40, C.I. I. Direct Blue 25, C.I. I. And oil-soluble dyes such as Direct Blue 86.

Examples of the black colorant include various carbon blacks manufactured by a thermal black method, an acetylene black method, a channel black method, a furnace black method, a lamp black method and the like.

Modified dyes and pigments can be used, and two or more dyes can be blended for use. In addition, low-molecular-weight polypropylene, low-molecular-weight polyethylene, liquid paraffin, acid amide, stearic acid wax, montan wax, sasol wax, caster wax, chlorinated paraffin, carnauba wax, rice wax, and other waxes affect color reproducibility. May be used in an amount not giving 0.5 to 5 parts by weight.

As the external additive, silica fine particles, metal oxide fine particles, a cleaning aid and the like are used. Examples of the silica fine particles include silicon dioxide, aluminum silicate, sodium silicate, zinc silicate, and magnesium silicate. Examples of the metal oxide fine particles include zinc oxide, titanium oxide, aluminum oxide, zirconium oxide, strontium titanate, and barium titanate.

Examples of the cleaning aid include fine resin powders such as olimethyl methacrylate, polyvinylidene fluoride, and polytetrafluoroethylene. If necessary, 0.2 to 2 parts by weight may be used. These external additives
Surface treatment such as hydrophobization may be performed.

As the method for producing the toner, the mixing and dispersing means include a wet dispersing method such as a high-speed dissolver, a roll mill and a ball mill, and a melt-kneading method using a roll, a pressure kneader, an internal mixer, a screw type extruder and the like. And the like, and as a mixing means, a ball mill, a V-type mixer, a Folberg, a Henschel mixer, or the like can be used. As a means for coarsely pulverizing the mixture, for example, a hammer mill, a cutter mill, a roller mill, a ball mill, or the like can be used. As a means for finely pulverizing the coarsely pulverized product, a jet mill, a high-speed rotary pulverizer, or the like can be used. As a means for classifying the finely pulverized material, an air flow classifier or the like can be used.

[0055]

The present invention will be described below in detail with reference to examples. In the following, parts used in the composition mean parts by weight.
The development was performed using the developing device shown in FIG. Although four developing devices shown in FIG. 1 were used as a full-color copying machine, only one developing device is shown in the embodiment. The developing conditions are as follows.
Was rotated in the direction of arrow a at a peripheral speed of 130 mm / sec.
On the surface of the photoreceptor drum 10, a dark portion -60 is formed as an electrostatic latent image.
An electric charge of 0 V and a light portion of -50 V were formed, and the distance from the sleeve was set to 0.45 mm. -450 for the above sleeve
The development was performed at a frequency of 4 kHz in which a voltage of V was superimposed and a peak voltage of the waveform of 1.2 kV.

Example 1 A material having the following composition was melt-kneaded, then pulverized and classified to obtain a fine yellow powder having an average particle diameter of 8 μm.

95 parts of a linear polyester having an acid value of 10 KOH mg / g and a glass transition point of 60 ° C. 95 parts of a boron-based compound (1) 2 parts of Pigment Yellow 180 3 parts
5 parts were added and mixed to obtain a yellow toner.

Next, 95 parts of ferrite particles coated with a resin containing a silicone resin as a main component were mixed with 5 parts of the obtained yellow toner using a mixer, and the mixture was put into the developing device of FIG. An image was formed. As a result, a good image was obtained.

Similarly, a negative magenta fine powder having an average particle diameter of 8 μm comprising 93 parts of a linear polyester having an acid value of 10 KOH mg / g and a glass transition point of 60 ° C., 2 parts of a boron-based compound (1) and 5 parts of Pigment Red 184 was prepared. 0.5 part of chargeable colloidal silica was added to obtain a magenta toner.

Negatively-chargeable colloidal silica having an average particle diameter of 8 μm and consisting of 94 parts of a linear polyester having an acid value of 10 KOH mg / g and a glass transition point of 60 ° C. and 2 parts of a boron-based compound (1) and 4 parts of phthalocyanine blue was used. 0.5 part was added to obtain a cyan toner.

A black fine powder having an average particle diameter of 8 μm comprising 93 parts of a linear polyester having an acid value of 10 KOH mg / g and a glass transition point of 60 ° C., 2 parts of a boron-based compound (1) and 5 parts of carbon black was prepared. 5 parts were added to obtain a black toner.

Each of the four color toners was mixed with a ferrite particle coated with a silicone resin and charged into each developing device to form a full-color image. As a result, color reproducibility is good,
A clear full-color image with no fog and good gradation was obtained. Even after repeated image formation (20,000 sheets), a stable image was obtained.

High temperature and high humidity (30 ° C., 85% RH);
A stable full-color image was obtained even at low temperature and low humidity (10 ° C., 20% RH). Table 1 below shows the obtained image characteristics, color reproducibility, high temperature and high humidity, and low temperature and low humidity.

In the table, the image characteristics are as follows: 場合 indicates that a stable image was obtained without any change compared to the initial image after repeated formation of 20,000 sheets of images; Was evaluated as x.

Regarding the color reproducibility, when the color difference ΔE ≦ 10 with respect to the standard color set in advance and when the OHP projected image has no shadow, ○, when the color difference ΔE> 10,
The case where a shadow occurred in the projected image of P was evaluated as x.

Regarding the high-temperature and high-humidity image characteristics, ○ indicates that an image equivalent to normal temperature and normal humidity was obtained after repeated image formation of 20,000 sheets, and を indicates that image deterioration, especially fog, increased compared to normal temperature and normal humidity. It evaluated as x.

Regarding the low-temperature and low-humidity image characteristics, ○ indicates that an image equivalent to normal temperature and normal humidity, such as image density, was obtained after repeated image formation of 20,000 sheets, and を indicates that image deterioration such as a decrease in image density occurred. It evaluated as x.

Example 2 A four-color toner was obtained in the same manner as in Example 1 except that a linear polyester having an acid value of 50 KOH mg / g and a glass transition point of 65 ° C. was used, and was similarly charged into each developing device. .

The distance from the sleeve was set to 0.3 mm. The sleeve was developed under the conditions of a frequency of 3 kHz in which a voltage of -400 V was superimposed and a peak voltage of the waveform of 0.7 kV. A full-color image was formed in the same manner as in Example 1. Thus, a clear full-color image with good gradation was obtained. Even after repeated image formation (20,000 sheets), a stable image was obtained.

A stable full-color image was obtained even at high temperature and high humidity (30 ° C., 85% RH) and low temperature and low humidity (10 ° C., 20% RH). In addition, the obtained image characteristics, color reproducibility,
Table 1 below shows the high temperature and high humidity and the low temperature and low humidity.

Example 3 A four-color toner was obtained in the same manner as in Example 1 except that a linear polyester having an acid value of 30 KOH mg / g and a glass transition point of 45 ° C. and boron compound (4) were used. Each of the developing devices was charged.

The distance from the sleeve was set to 1 mm. The sleeve was developed under the conditions of a frequency of 6 kHz in which a voltage of -500 V was superimposed and a peak voltage of the waveform of 2 kV. As a result, a full-color image was formed in the same manner as in Example 1. A clear full-color image with good tonality was obtained. Even after repeated image formation (20,000 sheets), a stable image was obtained.

High temperature and high humidity (30 ° C., 85% RH);
A stable full-color image was obtained even at low temperature and low humidity (10 ° C., 20% RH). Table 1 below shows the obtained image characteristics, color reproducibility, high temperature and high humidity, and low temperature and low humidity.

Comparative Example 1 A toner of four colors was obtained in the same manner as in Example 1 except that a linear polyester having an acid value of 3 KOH mg / g, a glass transition point of 60 ° C., and boron compound (4) were used. Each of the developing devices was charged.

The distance from the sleeve was set to 0.5 mm. When the sleeve was developed under the conditions of a frequency of 4 kHz in which a voltage of -450 V was superimposed and a peak voltage of the waveform of 1.2 kV, a full-color image was formed. A clear full-color image is obtained, and the range of color reproducibility is good.
Was also good in transparency. However, when the image was repeatedly formed, the image deteriorated on 10,000 sheets,
Toner scattering occurred.

Table 1 below shows the obtained image characteristics, color reproducibility, high temperature and high humidity, and low temperature and low humidity. Comparative Example 2 A four-color toner was obtained in the same manner as in Example 1 except that a linear polyester having an acid value of 10 KOH mg / g and a glass transition point of 60 ° C., and a chromium compound were used, and were similarly charged into the respective developing devices. .

The distance from the sleeve was set to 0.5 mm. The sleeve was developed under the conditions of a frequency of 4 kHz in which a voltage of -450 V was superimposed and a waveform peak voltage of 1.2 kV. When a full-color image was formed, color reproducibility was poor and transparency in OHP was poor. I was

Table 1 below shows the obtained image characteristics, color reproducibility, high temperature and high humidity, and low temperature and low humidity. Comparative Example 3 Development was carried out in the same manner as in Example 1 except that the washed polyester having an acid value of 45 KOH mg / g and a glass transition point of 60 ° C. and the boron compound (4) were used. OHP permeability was also good. But,
When images were repeatedly formed, image deterioration occurred on 5,000 sheets. Table 1 below shows the obtained image characteristics, color reproducibility, high temperature and high humidity, and low temperature and low humidity.

[0079]

[Table 1]

From Table 1 above, as shown in Examples 1 to 3, when the developer according to the present invention is used, a good image can be obtained even when images are repeatedly formed. As shown in Example 3, when the acid value of the polyester resin is out of the range of the present invention, the charging characteristics are poor, and the image characteristics and the image characteristics at high temperature and high humidity are poor.
Further, as shown in Comparative Example 2, when the chromium complex was used, the charging characteristics were poor in any environment and the image characteristics were deteriorated.

[0081]

According to the present invention, by using a combination of a polyester resin having an appropriate acid value and a glass transition point with a boron-based complex compound, a developer having stable charging characteristics during repeated image formation. Is obtained. Further, according to the present invention, since the polyester resin is excellent in transparency and the boron-based complex compound has no coloring property, an image excellent in color reproducibility can be obtained by using this developer.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a developing device used in the present invention.

[Description of sign]

 Reference Signs List 10 photosensitive drum 12 charging device 14 developing device 16 transfer device 18 cleaning device 19 static elimination device

Claims (8)

[Claims] An acid value of 5 to 30 KOH mg / g and 45
A developer comprising a linear polyester resin having a glass transition point of up to 65 ° C., a colorant, and a toner containing at least a boron complex compound. 2. The toner according to claim 1, wherein the colorant is 1 to 15 with respect to the total amount of the toner.
2. The developer according to claim 1, wherein the boron-based complex compound is contained in an amount of 0.5 to 5 parts by weight based on the total amount of the toner. 3. The boron-based complex compound has the following general formula (1): The developer according to claim 1, wherein the developer is represented by: 4. An electrostatic latent image forming step of forming an electrostatic latent image on an image carrier, the electrostatic latent image having an acid value of 5 to 30 KOH mg / g and a glass transition point of 45 to 65 ° C. Developing using a developer containing a toner containing at least a linear polyester resin, a colorant, and a boron-based complex compound to form a visible image. Method. 5. An electrostatic latent image forming step of forming an electrostatic latent image on an image carrier, and 5 to 30 KOH mg / mg on a developing roller.
forming a magnetic brush using a linear polyester resin having an acid value of g and a glass transition point of 45 to 65 ° C., a colorant, and a toner including at least a boron-based complex compound, and a developer including a carrier; Developing an electrostatic latent image by applying an alternating electric field between the image carrier and the developing roller to form a visible image. 6. The toner according to claim 1, wherein the colorant is one to the total amount of the toner.
The developing method according to claim 4, wherein the boron complex compound is contained in an amount of 0.5 to 5 parts by weight based on the total amount of the toner. 7. The boron-based complex compound has the following general formula (1): The developing method according to any one of claims 4 to 6, wherein 8. A distance between the developing roller and the image carrier is 0.1 to 1 mm, and the alternating electric field is a DC voltage of minus 300 to minus 600 V superimposed thereon, and a frequency of 1
The developing method according to any one of claims 5 to 7, wherein the developing voltage is 10 to 10 kHz and the peak voltage of the waveform is 0.5 to 3 kV.