JPH11149177A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method in which the time taken to remove toner remaining on an intermediate transfer body after transfer is shortened so as to improve cleaning performance. SOLUTION: After secondary transfer, the residual toner on the intermediate transfer body 5 is electrostatically charged to have a polarity reverse to the polarity of the toner at the time of developing by a residual toner electrostatic charge means, and the residual toner is reversely transferred to an image carrier simultaneously with primary transfer so as to remove the residual toner on the transfer body 5; (1) the electrostatic charge amount of the toner on the image carrier after developing is -5 to -20 μC/g, (2) the electrostatic charge amount of the toner on the transfer body 5 before the secondary transfer is -10 to -40 μC/g, (3) the electrostatic charge amount of the toner remaining on the transfer body 5 after electrostatically charging the residual toner remaining on the transfer body 5 to have the polarity reverse to the polarity of the toner at the time of developing after secondarily transferring a toner image tranferred to the transfer body 5 to the transfer material at the 2nd transfer position of the transfer body 5 is +20 to +40 μC/g. Then, the toner has at least binding resin, colorant and wax.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method used in a recording method utilizing an electrophotographic method, an electrostatic recording method, a magnetic recording method, or the like. More specifically, the present invention relates to an image forming method used for a copying machine, a printer, and a facsimile, which forms a toner image on an electrostatic latent image carrier in advance and then transfers the image onto a transfer material to form an image.

[0002]

2. Description of the Related Art A plurality of color toner images formed on a photoreceptor serving as an electrostatic latent image carrier are sequentially superimposed on an intermediate transfer member and primary-transferred. A color image forming apparatus that obtains a color image or a single color image by collectively and secondarily transferring a color image or a single color image onto a transfer material is known.

However, in an image forming apparatus using the above-described intermediate transfer member, after secondary transfer from the intermediate transfer member to a transfer material such as paper, transfer residual toner is present on the intermediate transfer member, The removal and processing of the residual toner is one technical problem.

As means for solving the above problem, for example, a type in which an elastic blade is brought into contact with or separated from an intermediate transfer member to scrape toner on the intermediate transfer member (Japanese Patent Application Laid-Open No. 56-1)
53357, and JP-A-5-303310).

Further, a fur brush is provided for contacting and separating from the intermediate transfer member, and a bias having a polarity opposite to that of the secondary transfer residual toner on the intermediate transfer member is applied to the fur brush to collect the residual toner. There is also a configuration in which toner is once attached to a bias roller such as a metal roller and then scraped off with a blade.

Further, when the photoreceptor is not performing the transfer step, the residual toner on the intermediate transfer body is returned to the photoreceptor by an electric field, and the residual toner is collected by a cleaner for the photoreceptor. JP-A-340564, JP-A-5-29
No. 7739 and JP-A-1-105980.

Here, in any of the proposals, the toner returned to the photoconductor has the same polarity as the polarity of the toner image formed on the photoconductor.

[0008]

However, the above-described cleaning of the intermediate transfer member has the following disadvantages.

That is, in a cleaning device such as a cleaning blade that mechanically scrapes off toner on the intermediate transfer member, the toner deposited on the blade portion when the blade separates remains on the intermediate transfer member. In addition, there is a problem that blade marks are generated on the image of the printing process. Further, if the blade and the intermediate transfer member facing the blade are worn for a long period of time, problems such as a decrease in transfer efficiency due to deterioration of the surface layer of the intermediate transfer member and a toner slipping through the cleaning blade also occur.

Further, the apparatus for recovering the residual toner on the intermediate transfer member using the fur brush has a disadvantage that the cleaning device is large, complicated, and expensive.

When returning the residual toner on the intermediate transfer member having the same polarity as the polarity of the toner image formed on the photosensitive member to the photosensitive member, the residual toner is removed when the normal transfer step is not performed. It is necessary to provide a process for reverse transcription. Therefore, the number of transfer materials that can be output during a limited time, that is, the so-called throughput decreases.

An object of the present invention is to solve the above-mentioned problem of an image forming method using an intermediate transfer member.

That is, an object of the present invention is to reduce the time required for cleaning the toner remaining on the intermediate transfer member after transfer, thereby reducing the time required for image formation, and the acid value of the resin contained in the toner. Is to further improve the cleaning property of the toner remaining on the intermediate transfer member after the secondary transfer.

Still another object is to simplify the entire apparatus by configuring the apparatus without providing a dedicated container for collecting and storing the toner remaining on the intermediate transfer member.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an image bearing member, a toner image forming means for forming a toner image on the image bearing member, and an intermediate transfer member facing the image bearing member. Bias applying means for primary-transferring the toner image formed on the image carrier to the intermediate transfer body at a first transfer position of the intermediate transfer body; and transferring the toner image transferred to the intermediate transfer body to the intermediate transfer body. Transfer means for secondary transfer to a transfer material at a second transfer position of the body, and residual toner charging means for charging residual toner remaining on the intermediate transfer body after transfer to a polarity opposite to the polarity of the toner during development In the image forming method having
After the secondary transfer, the residual toner on the intermediate transfer body is charged to the polarity opposite to the polarity at the time of development of the toner by the residual toner charging means, and the primary transfer position of the charged residual toner is changed during the primary transfer. The residual toner on the intermediate transfer member is removed by reversely transferring the residual toner to the image carrier at the same time as the primary transfer by passing the toner, and the charge amount of the developed toner on the image carrier is −5 to −5. −20 μC / g, the charge amount before the secondary transfer on the intermediate transfer member is −10 to −40 μC / g, and the toner image transferred to the intermediate transfer member is transferred to the transfer material at the second transfer position of the intermediate transfer member. After the next transfer, the residual toner remaining on the intermediate transfer member is charged to a polarity opposite to the polarity at the time of development of the toner, and the charge amount of the toner remaining on the intermediate transfer member is +20 to
+40 μC / g, wherein the toner has at least a binder resin, a colorant, and a wax.

The charge amount of the toner on the image carrier is -5 μC /
g, the primary transfer of the toner from the image carrier to the intermediate transfer member is deteriorated.
The cleaning property of the toner remaining on the image carrier after the toner on the image carrier is primarily transferred to the intermediate transfer body is deteriorated. When the charge amount of the toner before the secondary transfer on the intermediate transfer member is less than −10 μC / g, the secondary transfer onto the transfer material is deteriorated. The phenomenon where the image is scattered is seen.

Further, after the toner image transferred onto the intermediate transfer member is secondarily transferred to a transfer material at a second transfer position of the intermediate transfer member, residual toner remaining on the intermediate transfer member is developed. When the charge amount of the toner remaining on the intermediate transfer body after being charged to the polarity opposite to the polarity at the time is less than +20 μC / g, the toner remaining on the intermediate transfer body does not reversely transfer onto the image carrier, and the intermediate transfer The residual toner remains on the body as it is, and appears as a positive ghost in the next image.
If it is larger than C / g, the toner remaining on the intermediate transfer body adheres to the toner on the photoconductor of the next image, and as a result, the toner portion of the next image on the photoconductor drum becomes on the intermediate transfer body. It is not transferred and appears as a negative ghost.

Therefore, the charge amount of the toner on the image carrier is -5 to -20 .mu.C / g, and the charge amount before the secondary transfer on the intermediate transfer member is -10 to -40 .mu.C / g. After the second transfer of the toner image to the transfer material at the second transfer position of the intermediate transfer member, the remaining toner remaining on the intermediate transfer member is charged to a polarity opposite to the polarity of the toner during development. The charge amount of the residual toner on the transfer member is +20 to +40 μ
C / g is preferable, and when the acid value of the resin contained in the toner is 5 to 25, the charge amount can be stably obtained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intermediate transfer member cleaning means, which is a feature of the present invention, will be described below with reference to FIG.

The intermediate transfer member cleaning means of the present invention comprises:
At the same time as the primary transfer from the photosensitive drum 1 to the intermediate transfer member 5 as shown in FIG.
It is characterized in that it can be transferred to the photosensitive drum 1 and returned.

When the toner is transferred from the intermediate transfer member 5 to the paper by the transfer belt 6, the secondary transfer residual toner receives a strong electric field having a polarity opposite to that of the toner, and has a regular charging polarity (in this embodiment, Negative polarity) opposite polarity (positive polarity in this example)
And the amount of toner remaining on the intermediate transfer member 5 is large. However, not all the toners are inverted to the positive polarity, but are partially neutralized. Some toners have no charge and some maintain the negative polarity.

Accordingly, the present inventors have developed a charging means for inverting the neutralized toner having no charge and the toner maintaining negative polarity among the secondary transfer residual toner on the intermediate transfer member 5 to the opposite polarity. Was provided after the secondary transfer.

Further, the oppositely charged toner on the intermediate transfer member 5 and the regular toner which is primarily transferred on the photosensitive drum 1 do not cancel each other out by short-time contact.
At the primary transfer nip portion between the photosensitive drum 1 and the intermediate transfer member 5, it was found that the reversely charged toner was transferred to the photosensitive drum 1 and the normally charged toner was transferred to the intermediate transfer member 5.

This occurs because the electric field applied between the photosensitive drum 1 and the intermediate transfer member 5 at the primary transfer nip is weakened by lowering the primary transfer bias, and the electric discharge at the nip portion is caused. By suppressing toner charging, when the primary transfer nip passage time of the toner is short, the charge canceling action does not work, so that the toner on the photosensitive drum 1 and the toner on the intermediate transfer body 5 have independent behavior. To take.

In FIG. 1, contact type charging means is used as secondary transfer residual toner charging means on the intermediate transfer member 5.
Specifically, an elastic roller having a plurality of layers was used as the intermediate transfer member cleaning roller 8.

FIG. 2 is a schematic sectional view of the intermediate transfer member cleaning roller 8 actually used in the present invention.

The intermediate transfer member cleaning roller 8 has a roller shape having at least an elastic layer 82 made of rubber, elastomer, or resin on a cylindrical conductive support 83, and one or more elastic layers 82 on the elastic layer. Of a roller shape having the coating layer 81 of FIG.

The cylindrical conductive support 83 may be made of any material that can be abutted with rigidity such that the nip is uniform in the longitudinal direction without bending to the intermediate transfer member 5. Metals and alloys such as copper and stainless steel, and conductive resins in which carbon and metal particles are dispersed can be used.

The elastic layer 82 has only to have a hardness capable of abutting on the intermediate transfer member 5 without a gap, and have a certain electrical withstand voltage against an applied bias.

Specific rubber materials include acrylonitrile-butadiene rubber (NBR), styrene butadiene rubber, butadiene rubber, ethylene propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylonitrile butadiene rubber, acrylic rubber, fluorine rubber Rubber and urethane rubber.

The resistance value is 10 in volume resistivity.⁷~ 1
0¹¹Ωcm (At the time of applying 1 kV). Intermediate transfer member
The required resistance value of the leaning roller will be described later.
You.

The material used for the coating layer 81 is preferably a material in which a metal compound such as titanium oxide or tin oxide is dispersed as a conductive material in a nylon resin, a urethane resin, a fluororesin, or the like, and the resistance is controlled.

Also, a type in which a sheet-like or tube-like resin is wound as the coating layer may be used.

The resistance of the coating layer needs to have a sufficient surface resistance to be discharged in contact with the intermediate transfer member. Its value is 10 ⁶ to 10 ¹⁵ Ωcm ² (when 1 kV is applied).
Is valid. 100 × 100m for surface resistance measurement
m, a sample in which a coating layer was applied to the conductive sheet under the same conditions as above was prepared, and an applied voltage of 1 kV, discha was used using R8340A and R12704 manufactured by Advantest.
rge 5 sec, charge 30 sec and me
This is a value measured under the conditions of assure 30 sec.

Intermediate transfer member cleaning used in this embodiment
The configuration of the grawler 8 is a stainless steel core with an outer diameter of φ14 mm.
An NBR having a thickness of 3 mm as an elastic body 82 on a gold 83
Product resistivity 10⁹Ωm (At the time of 1 kV application)
81 is a methoxymethylated polyamide which is a nylon resin
A material obtained by dispersing titanium oxide in amide was used. Its thickness
30 μm, surface resistance value is 10⁸Ωcm^TwoIt is. Outer diameter is about
φ20 mm.

The actual working resistance of the roller was measured by the method shown in FIG. The actual resistance used here refers to the resistance of the intermediate transfer body cleaning roller including the elastic layer and the coating layer.

In FIG. 3, the aluminum cylinder 71 is rotated by a rotation drive shaft (not shown), and the intermediate transfer body cleaning roller 8 is driven to rotate accordingly. The contact pressure is equivalent to the actual use condition of the actual machine, and the total pressure is 1 kgf. A constant DC voltage _Vdc is applied to the core of the intermediate transfer member cleaning roller 8 from the high voltage power supply 73. The current flowing through the elastic layer and the coating layer of the intermediate transfer member cleaning roller 8 flows into the aluminum cylinder 71 and is grounded via the standard resistor 72. Assuming that the voltage at both ends of the standard resistor 72 is V _r [V], the intermediate transfer body cleaning roller 8
Is given by the following equation.

Rc [Ω] = 10 ⁶ / _Vr [V]

As a result of the measurement, the actual use resistance of the intermediate transfer member cleaning roller was 4 × 10 ⁸ Ω.

According to the study of the present inventor, it has been found that the actual use resistance value desired for the intermediate transfer body cleaning roller can be used in the range of 5 × 10 ⁵ to 1 × 10 ⁹ Ω by the above-mentioned measuring method. Was.

The thickness of the coating layer 81 is 5 to 100 μm.
It was confirmed that it was effective.

Further, by having an inorganic fine powder on the surface of the toner particles, the charge amount of the toner on the image carrier after development, the toner charge amount on the intermediate transfer member before the secondary transfer, and After the toner image transferred to the intermediate transfer member is secondarily transferred to the transfer material at the second transfer position of the intermediate transfer member,
After the residual toner remaining on the intermediate transfer member is charged to a polarity opposite to the polarity at the time of developing the toner, the charge amount of the toner remaining on the intermediate transfer member can be stably obtained.

The method for measuring the charge amount (two-component tribo value) of the toner according to the two-component method in the present invention is described below.

Under an environment of 23 ° C. and a relative humidity of 60%, a mixture of 9.5 g of carrier and 0.5 g of toner added to 9.5 g of carrier was used as a carrier in a 50-100 ml polyethylene bottle using EFV200 / 300 (Powdertech). And shake by hand 50 times. Then, at the bottom, 500
1.0 to 1.2 g of the mixture is placed in a metal measuring container having a mesh screen, and a metal lid is closed. At this time, the weight of the entire measurement container is weighed to be W1 g. next,
In a suction machine (at least a portion in contact with the measurement container is an insulator), the pressure of the vacuum gauge is adjusted to 2450 Pa (250 mmAq) by adjusting the air flow control valve by suctioning from the lower part of the suction port. In this state, suction is performed for 1 minute through a 500 mesh screen to remove the toner by suction. The potential of the electrometer at this time is defined as V (volt). Here, a capacitor is connected to the ammeter, and the capacitance is C (μF). Further, the weight of the entire measuring machine after suction is weighed and is defined as W2 (g). The triboelectric charge (μC / g) of this toner is calculated as in the following equation.

Triboelectric charge (μC / g) = CV / (W1−W2)

The specific surface area (BET) of the toner is 0.9-0.9.
It is preferably 1.3 m ² / g, and if it is less than 0.9 m ² / g, the developability under high temperature and high humidity deteriorates, and the
If it exceeds ² / g, the transferability of the toner deteriorates.

The specific surface area was determined by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics) according to the BET method, and calculating the specific surface area using the BET multipoint method.

The toner of the present invention preferably has a weight average particle size of 4 to 9 μm.

Further, the toner of the present invention has a value C of viscoelastic tan δ at 100 ° C. and a viscoelastic t at 150 ° C.
The value of the ratio D / C to the value D of an δ is D / C ≧ 1, and
The value E of viscoelastic tan δ in the range of 50 ° C. to 190 ° C. is 3.0 ≧ E ≧ 0.5. D /
When the C value and the E value satisfy the above range, the resin is in a specific state during kneading during the production of the toner, and as a result,
It is possible to stably obtain the above-mentioned toner charge amounts defined by the present invention.

If the D / C value is less than 1, or if the E value exceeds 3.0 or is less than 0.5, the above-specified toners (1) to (4) cannot stably obtain the charge amount.
When the E value is 2.5 ≧ E ≧ 1.5, the above characteristics are further improved.

The viscoelastic tan δ is measured by a viscoelasticity measuring device RDA.
Using a type II (manufactured by Rheometrics), a parallel plate having a diameter of 25 mm as a measuring jig, a measuring frequency of 6.28 radians / second, and a measuring temperature of 100 ° C. to 20 ° C.
The temperature was measured at a rate of 1 ° C./min to 0 ° C.

The toner of the present invention has an endothermic peak of 120 ° C. or less (more preferably 1 ° C. or less) in its differential thermal analysis.
10 ° C. or less).

The endothermic peak in the differential thermal analysis was 120 ° C.
If not, the effect of the present invention cannot be sufficiently obtained.
In a toner having an endothermic peak of 120 ° C. or less in differential thermal analysis, the state of dispersion of the magnetic substance / charge control agent in the binder resin in the melt-kneading step in the production thereof is as follows.
It is assumed that the toner has a specific state different from the toner having an endothermic peak not higher than 120 ° C. The certain unusual state affects the surface properties of the toner of the present invention, and the toner can stably obtain the charge amount of the above-mentioned toners defined by the present invention.

The endothermic peak in the differential thermal analysis was 120 ° C.
At least one of the following is effective, and the endothermic peak may be in a place exceeding 120 ° C. However, it is preferable that the endothermic peak in the differential thermal analysis does not exist below 60 ° C. (preferably below 70 ° C.). When the endothermic peak in the differential thermal analysis exists below 60 ° C., the image density tends to decrease. In addition, storage stability tends to be unstable.

As a means for causing the toner to have an endothermic peak in the differential thermal analysis of the toner in a temperature range of 120 ° C. or less, the toner has an endothermic peak in the differential thermal analysis in a temperature range of 120 ° C. or less. A method of internally adding a compound is preferred.

The endothermic peak in the differential thermal analysis was 120 ° C.
Examples of the substance having one or more of the following temperature ranges include a resin and a wax.

Examples of the resin include polyester resins and silicone resins having crystallinity.

As the wax, paraffin wax,
Petroleum waxes such as microcrystalline wax and petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon waxes and derivatives thereof by the Fischer-Tropsch process; polyolefin waxes and derivatives thereof represented by polyethylene; carnauba wax and candelilla wax. Alcohols such as higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid or derivatives thereof; acid amides and derivatives thereof, esters and derivatives thereof, ketones and derivatives thereof, hydrogenated castor oil and derivatives thereof. Any of plant waxes, animal waxes and the like having an endothermic peak at 120 ° C. or lower in differential thermal analysis can be used.

Among them, the compound of the present invention having an endothermic peak at 120 ° C. or lower in differential thermal analysis contains a polyolefin, a hydrocarbon wax by Fischer-Tropsch method, a petroleum wax or a higher alcohol. Is particularly preferred.

When one of the above compounds is used, the charge amount of the toner specified in the present invention can be stably obtained. These compounds have relatively low polarities themselves and are considered to stabilize the charge of the toner matrix.

For the measurement of the endothermic peak of the toner according to the present invention, a DSC curve measured by a high-precision internal heating type input compensation type differential scanning calorimeter such as DSC-7 manufactured by Perkin Elmer Co. is used. Used.

In the toner of the present invention, the value of the shape factor SF-1 measured by an image analyzer for toner particles is 110 <SF−
1 ≦ 180 (more preferably 120 <SF−1 ≦ 16
0), and the value of the shape factor SF-2 is 110 <SF-2
≦ 140 (more preferably 115 <SF-1 ≦ 140)
And a value B obtained by subtracting 100 from the value of SF-2 and SF-
It is preferable that the ratio B / A to the value A obtained by subtracting 100 from the value of 1 is 1.0 or less (more preferably 0.2 to 0.95).

When SF-1 is 110 or less,
When F-2 is 110 or less, and when the ratio B / A is 1.0
In the case where the ratio exceeds the limit, it is difficult to clean the transfer residual toner remaining on the latent image carrier, and cleaning failure is likely to occur.

When SF-1 exceeds 180, and when SF-1
When -2 exceeds 140, high transfer efficiency cannot be obtained.

In the present invention, SF-
1, SF-2 is, for example, FE-SEM manufactured by Hitachi, Ltd.
Using (S-800), 100 toner images of 2 μm or more, which were enlarged 1000 times, were randomly sampled, and the image information was introduced into, for example, an image analyzer (Luzex III) manufactured by Nicole, via an interface. Analysis is performed, and the value calculated from the following equation is used as the shape factor SF-1, S
Defined as F-2.

[0066]

(Equation 1) (Where MXLNG is the absolute maximum length of the particle, PERIME
Is the perimeter of the particle, AREA is the projected area of the particle)

For the weight average particle diameter of the toner of the present invention, a Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Inc.) is used. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant (preferably an alkylbenzene sulfonate) is added as a dispersing agent to 100 to 150 ml of the electrolytic aqueous solution, and a sample to be measured is 2-2.
Add 0 mg. The electrolyte in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the volume and number distribution of the toner having a size of 2 μm or more are measured by using the above-mentioned apparatus using a 100 μm aperture as the aperture. Was calculated. Then, a volume-based weight average particle diameter (D4) determined from the volume distribution according to the present invention was determined.

The kind of the binder resin used in the present invention includes, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and a substituted product thereof; styrene-p-chlorostyrene copolymer. Coalescing,
Styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer Polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer,
Styrene-based copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic Resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin and petroleum resin can be used. Crosslinked styrenic resins are also preferred binder resins.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Double such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide A monocarboxylic acid having a bond or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, or dimethyl maleate and a substituted product thereof; for example, vinyl chloride, vinyl acetate, Vinyl esters such as vinyl benzoate; ethylene olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl methyl ether Vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether; and the like. These vinyl monomers are used alone or in combination.

As the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used, for example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, Carboxylic acid esters having two double bonds such as ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinyl compounds of divinylaniline, divinylether, divinylsulfide and divinylsulfone; and three or more vinyl groups. Can be used alone or as a mixture.

In the toner of the present invention, it is preferable that a charge control agent is mixed (internally added) to the toner particles or mixed (externally added) with the toner particles before use. The charge control agent enables optimal charge control according to the development system.
In particular, in the toner of the present invention, the balance between the particle size distribution and the charge amount can be further stabilized.
Examples of the negative charge control agent for controlling the toner to negative charge include the following substances.

For example, organic metal complexes and chelate compounds are effective, and examples thereof include monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acid metal complexes, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids and aromatic polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The following substances are used as positive charge control agents for controlling the toner to be positively chargeable.

For example, denatured products with nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof. Onium salts such as phosphonium salts and their lake pigments; triphenylmethane dyes and these lake pigments (as the lacking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid,
Metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate; There is;

These charge control agents can be used alone or in combination of two or more.

The charge control agents described above are preferably used in the form of fine particles. In this case, the number average particle size of these charge control agents is particularly preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner, they are preferably contained in the toner in an amount of 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, based on 100 parts by weight of the binder resin.

The colorant used in the present invention can be adjusted to black by a black colorant such as carbon black, a magnetic substance, and a chromatic colorant such as a yellow colorant, a magenta colorant and a cyan colorant shown below. Is used.

Examples of the yellow colorant include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 97, 109, 1
10, 111, 120, 127, 128, 129, 14
7, 168, 174, 176, 180, 181, 191
Is preferably used.

As the magenta coloring agent, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds and basic dye lake compounds can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 1
5: 3, 15: 4, 60, 62, 66, etc. can be particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. In the present invention,
The colorant is selected in consideration of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. These chromatic colorants are used in an amount of 1 to 2 with respect to 100 parts by weight of the binder resin.
0 parts by weight contained in toner.

Examples of the magnetic material include metal oxides containing iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. Among them, those containing iron oxide as a main component, such as triiron tetroxide and γ-iron oxide, are preferred. From the viewpoint of controlling the chargeability of the toner, another element such as a silicon element or an aluminum element may be contained. These magnetic particles, BET specific surface area by nitrogen adsorption method is preferred 2~30m ² / g, especially 3~28m ² /
g, and a magnetic powder having a Mohs hardness of 5 to 7 is preferable.

The shape of the magnetic body is octahedron, hexahedron,
There are spheres, needles, scales, and the like, and shapes having little anisotropy, such as octahedron, hexahedron, sphere, and amorphous, are preferable for increasing the image density. As the average particle size of the magnetic material,
Preferably it is 0.05 to 1.0 μm, more preferably 0.1 to 1.0 μm.
1 to 0.6 μm, more preferably 0.1 to 0.4 μm
m is good.

When the content of the magnetic substance is preferably 30 to 200 parts by weight, more preferably 40 to 200 parts by weight, and still more preferably 50 to 150 parts by weight, based on 100 parts by weight of the binder resin, the content is remarkable. The effect appears. If the amount is less than 30 parts by weight, the toner resistance becomes too high and the toner charge amount becomes high, and if it exceeds 200 parts by weight, the toner resistance becomes too low and the toner charge amount becomes low and the toner charge amount becomes low. It is difficult to achieve the specified toner charge range.

As the inorganic fine powder contained in the toner of the present invention, known powders can be used. However, silica, alumina, titania or a combination thereof is used to improve charging stability, developability, fluidity and storage stability. It is preferable to be selected from oxides. Furthermore, silica is more preferable. For example, as the silica, both so-called dry silica produced by vapor phase oxidation of silicon halide and alkoxide or dry silica called fumed silica and so-called wet silica produced from alkoxide, water glass and the like can be used. However, there are few silanol groups on the surface and inside the silica fine powder, and Na ₂ O, SO ₃
Dry silica such as ^{2- which has} little production residue is preferred.
In the case of fumed silica, for example, in the manufacturing process,
By using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide, it is possible to obtain a composite fine powder of silica and another metal oxide, and these are included.

The content of the inorganic fine powder in the toner is preferably 0.1 to 8 with respect to 100 parts by weight of the toner.
It is preferred that the amount be from 0.5 to 5 parts by weight, more preferably from 0.5 to 5 parts by weight, and even more preferably from 1.0 to 3.0 parts by weight.

The inorganic fine powder used in the present invention may contain a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, and a functional group for the purpose of hydrophobicity and charge control as required. It is also preferable that the silane coupling agent and other treating agents such as an organic silicon compound and an organic titanium compound are used alone or in combination.

In the toner of the present invention, other additives such as lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder; cerium oxide powder, silicon carbide Powder,
Abrasives such as strontium titanate powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents;
Conductivity-imparting agents such as zinc oxide powder and tin oxide powder; and developability improvers such as organic fine particles of opposite polarity and inorganic fine particles of opposite polarity can also be used.

To prepare the toner according to the present invention, for example, a binder resin, a wax, a metal salt or a metal complex, a pigment as a colorant, a dye, or a magnetic substance, a charge controlling agent, and The additives were mixed well with a mixer such as a Henschel mixer and a ball mill, and then heated and kneaded using a hot kneader such as a kneader or extruder to melt and knead the resins with each other while mixing the metal compounds with each other. A method of dispersing or dissolving a pigment, a dye, or a magnetic substance, solidifying by cooling, pulverizing, and then performing classification and surface treatment to obtain toner particles, and adding and mixing inorganic fine powder, is preferably used. Either the classification or the surface treatment may be performed first.

In the classifying step, it is preferable to use a multi-segment classifier in terms of production efficiency. Examples of the surface treatment include a hot water bath method in which the pulverized toner particles are dispersed in water and heated, a heat treatment method in which the toner particles are passed through a hot air stream, and a mechanical impact method in which mechanical energy is applied and treated.
In the present invention, in the mechanical impact method, the processing temperature is set to a temperature around the glass transition point Tg of the toner particles (Tg ± 10 ° C.).
Is preferable from the viewpoints of prevention of aggregation and productivity. More preferably, the glass transition point T of the toner
Performing at a temperature in the range of g ± 5 ° C. can reduce pores having a radius of 10 nm or more on the surface and make the inorganic fine powder work effectively.

Further, the toner according to the present invention is disclosed in
The toner can be produced by using a method described in JP-A-6-13945 or the like or a method of atomizing the molten mixture into air to obtain a spherical toner using a disk or a multi-fluid nozzle.

The present invention is particularly effective when the charging means is a direct charging method in which the charging member is brought into contact with the image carrier. As compared with corona discharge or the like in which the charging means does not come into contact with the image carrier, the load on the surface of the image carrier is large, so that the improvement effect is remarkable in terms of the life of the image carrier.

One preferred embodiment of the electrostatic latent image carrier used in the present invention will be described below.

Examples of the conductive substrate include metals such as aluminum and stainless steel; plastics having a coating layer of aluminum alloy and indium oxide-tin oxide alloy; paper or plastic impregnated with conductive particles; or plastics having a conductive polymer. A cylindrical cylinder and a film.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coating properties are improved, the substrate is protected, defects on the substrate are covered,
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate and protecting the photosensitive layer against electrical breakdown. The undercoat layer is made of polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue,
It is made of gelatin, polyurethane or aluminum oxide material. The film thickness is usually 0.1 to 10 μm,
Preferably it is about 0.1 to 3 μm.

The charge generation layer is made of an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, a squarylium dye, a pyrylium salt, a thiopyrylium salt, a triphenylmethane dye, selenium, and amorphous. A charge generating substance such as an inorganic substance such as silicon is dispersed in a suitable binder, and is formed by coating or vapor deposition. The binder can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacryl resin, phenol resin, silicone resin, epoxy resin and vinyl acetate resin. No. The amount of the binder contained in the charge generation layer is 80% by weight.
Hereinafter, it is preferably selected from 0 to 40% by weight. Further, the thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transporting layer is formed by dissolving a charge transporting substance in a solvent together with a binder resin if necessary, and applying the solution. The film thickness is generally 5 to 40 μm. As the charge transport substance, biphenylene,
Polycyclic aromatic compounds having the structure of anthracene, pyrene or phenanthrene; nitrogen-containing cyclic compounds of indole, carbazole, oxadiazole or pyrazoline; hydrazone compounds; styryl compounds; selenium; selenium-tellurium; amorphous silicon; Is mentioned.

Examples of the binder resin for dispersing these charge transport materials include polycarbonate resin, polyester resin,
Thermoplastic resins such as polymethacrylate, polystyrene resin, acrylic resin, polyamide resin and poly-
Organic photoconductive polymers such as N-vinyl carbazole and polyvinyl anthracene are exemplified.

A protective layer may be provided as a surface layer. As the resin of the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins is used alone or in combination of two or more.

The conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals and metal oxides, preferably zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide-coated titanium oxide, tin-coated indium oxide, and antimony. Ultrafine particles of coated tin oxide and zirconium oxide can be mentioned. These may be used alone or as a mixture of two or more.

In general, when particles are dispersed in a protective layer,
In order to prevent scattering of the incident light by the dispersed particles, it is necessary that the particle size of the particles is smaller than the wavelength of the incident light, and the particle size of the conductive and insulating particles dispersed in the protective layer in the present invention is as follows. It is preferably 0.5 μm or less.

The content in the protective layer is preferably from 2 to 90% by weight, more preferably from 5 to 80% by weight, based on the total weight of the protective layer.

The thickness of the protective layer is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm.

The coating of the surface layer can be carried out by spray coating, beam coating or permeation coating of the resin dispersion.

[0105]

EXAMPLES All parts in the following formulations are parts by weight.

(Toner Production Example 1) ・ Styrene-butyl acrylate-butyl maleate 100 parts Half ester copolymer ・ Magnetic iron oxide 100 parts ・ Iron complex of monoazo dye 2 parts ・ Low molecular weight polyethylene (DSC endothermic peak 103. 8 ℃) 4 parts

The above materials were mixed in a blender,
Melt kneading with a heated twin-screw extruder, coarsely pulverize the cooled kneaded material with a hammer mill, finely pulverize the coarsely pulverized material with a jet mill, and classify the resulting finely pulverized material using a Coanda effect The toner was strictly classified by a machine to obtain magnetic toner particles. The magnetic toner particles are applied to a surface reformer of a type in which a rotor is rotated to apply a mechanical impact force to the magnetic toner particles.
Surface treatment was performed at 0 rpm (peripheral speed: 80 m / s) for 2 minutes. In addition, cooling water of 20 ° C. was passed through the surface reforming apparatus in order to control the internal temperature of the apparatus during the surface modification to a preferable range.

Next, dry silica having a primary particle diameter of 12 nm, which had been subjected to hydrophobic treatment with hexamethyldisilazane and silicone oil, was added to 100 parts of the obtained magnetic toner particles.
Was added and mixed with a mixer to obtain Magnetic Toner 1.
The obtained magnetic toner 1 has 141 of SF-1 and SF-2.
127, BET 0.95 m ² / g, 100 ° C.
The value of the ratio D / C between the value C of the viscoelastic tan δ at 150 ° C. and the value D of the viscoelastic tan δ at 150 ° C. is 1.95,
The value E of the viscoelastic tan δ in the range of 150 ° C. to 190 ° C. was 2.04 ≧ E ≧ 1.95. Table 1 shows other physical properties of the magnetic toner 1 thus obtained.

(Toner Production Examples 2 to 6) In the same manner as in Toner Production Example 1, except that resins having different acid values obtained by changing the monomer composition ratio of the resins used in Toner Production Example 1 were used. Toners 2 to 6 were obtained. Table 1 shows other physical properties of the obtained magnetic toners 2 to 6.

(Toner Production Example 7) Toner production example 1 except that the resin used in toner production example 1 had an acid value of 0.
In the same manner as in the above, magnetic toner 7 was obtained. Table 1 shows other physical properties of the obtained magnetic toner 7.

(Toner Production Example 8) The materials used in Toner Production Example 1 were mixed by a blender, melted and kneaded by a biaxial extruder heated to 90 ° C., and the cooled kneaded material was roughly pulverized by a hammer mill and roughly pulverized. The pulverized product was finely pulverized by a jet mill, and the obtained finely pulverized product was strictly classified by a multi-division classifier using Coanda effect to obtain magnetic toner particles. The magnetic toner particles were subjected to a surface treatment for 2 minutes at 1600 rpm (peripheral speed: 80 m / s) using a surface reforming apparatus of a type in which a rotor is rotated to apply a mechanical impact force. In addition, cooling water of 20 ° C. was passed through the surface reforming apparatus in order to control the internal temperature of the apparatus during the surface modification to a preferable range.

Next, 1.2 parts of dry silica having a primary particle size of 12 nm, which has not been subjected to a hydrophobic treatment, was added to 100 parts of the obtained magnetic toner particles and mixed with a mixer to obtain a magnetic toner 8. Was. Table 1 shows the physical properties of the magnetic toner 8 thus obtained.

(Comparative Toner Production Examples 1 and 2) In the same manner as in Toner Production Example 1, except that resins having different acid values obtained by changing the monomer composition ratio of the resins used in Toner Production Example 1 were used. Magnetic toners 9 and 10 were obtained. Table 1 shows other physical properties of the obtained magnetic toners 9 and 10.

[0114]

[Table 1]

(Example of Production of Intermediate Transfer Body) A rubber compound having the following composition was cross-extruded on a surface of an aluminum cylindrical roller having a diameter of 182 mm, a length of 320 mm, and a thickness of 5 mm using a mold, and the surface layer was polished. Thus, the roller 1 having the elastic layer was obtained.

Rubber compounding: 100 parts NBR 2 parts zinc oxide 10 parts conductive carbon black 30 parts paraffinic oil 2 parts vulcanizing agent 3 parts vulcanization accelerator

Also, a paint having the following formulation was prepared.

Coating composition: 100 parts of polyester polyurethane prepolymer (solid content 40% by weight) (including solvent) Hardener (including solvent) 50 parts (solid content 60% by weight) High lubricating powder PTFE particles 200 parts (particle size 0.3 μm) Dispersing aid (low molecular weight resin) 5 parts ・ Conductive titanium oxide particles (particle size 0.5 μm) 10 parts ・ Toluene (solvent) 80 parts

The dye was spray-coated on the outer peripheral surface of the roller 1 to form a coating layer having a thickness of 80 μm.
By heating at 1 ° C. for 1 hour, the residual solvent was removed, and the coating was crosslinked to obtain an intermediate transfer member 1 having a tough surface layer. The ratio of the PTFE particles in all the constituent components of the surface layer of the intermediate transfer body 1 was about 70% by weight based on the total solid content in the paint.

The intermediate transfer member 1 was heated at a temperature of 23 and a humidity of 65%.
The transfer surface of the intermediate transfer body 1 is placed on a 350 mm × 200 mm aluminum plate in a contact environment, and a voltage of 1 kV is applied between the aluminum cylinder on the inner surface of the intermediate transfer body 1 and the aluminum plate by a high voltage power supply. The potential difference before and after the 1 kΩ resistor connected in series with the power supply was measured and converted into a current value. Further, the volume resistance of the intermediate transfer body 1 was determined from the applied voltage and this current value. It was 10 ⁷ Ω.

Further, the average particle size used in the present example was 0.1.
The 3 μm PTFE particles were 40% of the comparative sample in the high lubricity judgment test described above.

As a photoreceptor, an Al cylinder having a diameter of 30 mm was used as a base. To this, layers having the configurations shown in (1) to (4) were sequentially laminated by dip coating to prepare a photoreceptor 1.

(1) Conductive coating layer: Mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin. The thickness is 15 μm.

(2) Undercoat layer: Mainly composed of modified nylon and copolymerized nylon. The film thickness is 0.6 μm.

(3) Charge generation layer: mainly composed of an azo pigment having absorption in a long wavelength region dispersed in butyral resin. The film thickness is 0.6 μm.

(4) Charge transporting layer: mainly composed of a hole transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight 20,000 according to the Oswald viscosity method) at a weight ratio of 8:10, and further comprising polytetrafluoroethylene. Powder (particle size: 0.2 μm) was added at 10% by weight based on the total solid content, and dispersed uniformly. 25 μm thick.

[0127] (intermediate transfer body cleaner) the intermediate transfer member cleaner, the conductive carbon in the upper layer of the dispersed urethane rubber having a coating layer formed by dispersing conductive tin oxide methoxymethyl nylon, about 10 ⁸ [Omega] cm A medium resistance roller having resistance was used, and a bias of +2.0 kV was applied during cleaning.

Example 1 The former intermediate transfer member 1, magnetic toner 1, and photosensitive member 1 were mounted on the image forming apparatus shown in FIG. 1 and evaluated based on the following conditions.

The organic photosensitive member 1 was used as the electrostatic latent image carrier, and the dark portion potential V _d = −600 V and the bright portion potential V _L = −100.
V. The black developing device is used at the position of the developing device BK shown in FIG. 1 and has a layer thickness of about 7
A developing sleeve in which a resin layer having a thickness of 2 μm and a JIS center line average roughness (Ra) of 2 μm was formed on a stainless steel cylinder having a diameter of 16φ with a blasted surface was used.

• 100 parts of phenolic resin • 90 parts of graphite (particle diameter 7 μm) • 10 parts of carbon black

Next, a gap between the photosensitive drum and the developing sleeve was set to 300 μm, a developing magnetic pole was set to 80 mT (800 gauss), and a urethane rubber blade having a thickness of 1.0 mm and a free length of 10 mm was used as a toner regulating member at 14.7 N / m.
(15 g / cm). As a developing bias, a DC bias component V _dc = −450 V, a superimposed AC bias component V _PP = 1200 V, and f = 2000 Hz were used.

The photosensitive member cleaning blade used for the photosensitive member cleaner has a thickness of 2.0 mm and a free length of 8 mm.
Urethane rubber blade of 24.5 N / m (25 g /
cm). The process speed was 94 mm / sec, and the ratio of the peripheral speed Vt of the developing sleeve to the peripheral speed V of the photoreceptor Vt / V was 1.5.

As an intermediate transfer member cleaning evaluation method,
First, a solid black image was printed, and the machine was stopped when the latent image came before the secondary transfer. Therefore, the charge amount of the toner present on the photosensitive drum and on the intermediate transfer member before the secondary transfer was measured. Next, a solid black image is printed again, and after the secondary transfer, the toner remaining on the intermediate transfer body is reversely charged. When the toner remaining on the intermediate transfer body reaches the photosensitive drum, the machine is stopped. Then, the charge amount of the toner remaining on the intermediate transfer member after the toner remaining on the intermediate transfer member after the secondary transfer was reversely charged was measured. Table 2 shows the results
Shown in

After the secondary transfer, after the toner remaining on the intermediate transfer member is reversely charged, a method for confirming whether the toner on the intermediate transfer member has returned to the photosensitive drum is as follows.
Print a 5mm square solid square on the sheet,
A halftone of a horizontal line of 1 dot and 2 spaces was printed on the first sheet, and it was visually evaluated how much a 5 mm square solid square pattern appeared as a ghost on the second halftone. Table 2 shows the results.

Examples 2 to 8 Evaluations using toners 2 to 8 were performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Examples 1 and 2 Evaluations were made using toners 9 and 10 in the same manner as in Example 1. Table 2 shows the results.

[0137]

[Table 2]

As shown in Table 2, when the toner has an acid value of 5 to 25, the charge amount of the toner on the photosensitive drum, the charge amount of the toner on the intermediate transfer member before the secondary transfer, and the secondary transfer The charge amount of the toner on the intermediate transfer member after the toner remaining on the intermediate transfer member was reversely charged was within the range specified in the present invention. As a result, a good image without ghost was obtained. Further, since the toner 8 used silica which had not been subjected to the hydrophobic treatment as an external additive, some negative ghosts occurred. On the other hand, in Comparative Example 1, since the acid value of the toner 9 is 0, the charge amount of the toner on the photosensitive drum, the charge amount of the toner on the intermediate transfer member before the secondary transfer, and the intermediate transfer member after the secondary transfer The charge amount of the toner on the intermediate transfer member after the toner remaining on the intermediate transfer member was reversely charged was not within the range specified in the present invention, and a positive ghost was generated. Also in Comparative Example 2, since the acid value of the toner was as large as 30, each charge amount of the toner did not fall within the range specified in the present invention, and positive ghost occurred.

[0139]

According to the present invention, the charge amount of the toner on the image carrier after development is -5 to -20 .mu.C / g, and the charge amount before the secondary transfer on the intermediate transfer member is -10 to -40 .mu.C. / G, and the toner image transferred to the intermediate transfer member is secondarily transferred to a transfer material at a second transfer position of the intermediate transfer member, and the remaining toner remaining on the intermediate transfer member is developed during development of the toner. The charge amount of the toner remaining on the intermediate transfer member after being charged to the polarity opposite to the polarity can be +20 to +40 μC / g. As a result, the cleaning property of the toner remaining after the secondary transfer is improved, and the ghost And a good image free of defects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus suitable for carrying out the present invention.

FIG. 2 is an explanatory diagram of an intermediate transfer member cleaning roller.

FIG. 3 is an explanatory diagram of a method for measuring an actual use resistance of an intermediate transfer member cleaning roller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charging roller 3 exposure 5 intermediate transfer member 6 transfer belt 8 cleaning roller 10 guide 11 registration roller 13 cleaner 15 fixing device 18 post-charger 28 secondary transfer bias source 29 primary transfer bias source 31 post-charge bias source 41 ~ 44 developer

──────────────────────────────────────────────────の Continuing on the front page (51) Int.Cl. ⁶ Identification code FI G03G 9/08 361 365 374 (72) Inventor Masao Takano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72 Inventor Hiroshi Yusa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (12)

[Claims] An image carrier, a toner image forming means for forming a toner image on the image carrier, an intermediate transfer member facing the image carrier, and a toner image formed on the image carrier are transferred to an intermediate transfer member. Bias applying means for primary transfer to the intermediate transfer body at a first transfer position of the intermediate transfer body; and secondary transfer of the toner image transferred to the intermediate transfer body to a transfer material at a second transfer position of the intermediate transfer body. An image forming method comprising: a transfer unit; and a residual toner charging unit that charges residual toner remaining on the intermediate transfer body after transfer to a polarity opposite to a polarity at the time of development of the toner. The residual toner on the body is charged to the polarity opposite to the polarity at the time of development of the toner by the residual toner charging means, and the charged residual toner is passed through the primary transfer position during the primary transfer, thereby achieving primary transfer. At the same time, the residual toner The residual toner on the intermediate transfer member is removed by reverse transfer to the image carrier, and the charge amount of the developed toner on the image carrier is -5 to -20.
μC / g, the charge amount before the secondary transfer on the intermediate transfer member is −1
After the toner image transferred to the intermediate transfer member is secondarily transferred to a transfer material at the second transfer position of the intermediate transfer member, the residual toner remaining on the intermediate transfer member is developed with the toner at 0 to -40 μC / g. The charge amount of the toner remaining on the intermediate transfer member after being charged to the polarity opposite to the polarity at the time is +20 to +40 μC / g, and the toner has at least a binder resin, a colorant, and a wax. Image forming method. 2. The resin contained in the toner having an acid value of 5-2.
The image forming method according to claim 1, wherein 3. The toner has a DSC endothermic peak of 60 to 60.
3. The image forming method according to claim 1, wherein at least one is present in a range of 120 [deg.] C. 4. The viscoelasticity ta of the toner at 100 ° C.
The value C of nδ and the value D of viscoelastic tan δ at 150 ° C.
And the value of D / C is D / C ≧ 1, and 150 ° C. to 19
The value E of the viscoelastic tan δ in the range of 0 ° C. is 3.0 ≧ E
The image forming method according to claim 1, wherein ≧ 0.5. 5. The image forming method according to claim 1, wherein the binder resin is a styrene copolymer. 6. The image forming method according to claim 1, wherein the toner is a magnetic toner containing 30 to 200 parts by weight of a magnetic substance with respect to 100 parts by weight of a binder resin. . 7. The inorganic fine powder contained in the toner is at least one kind of inorganic fine powder selected from titania, alumina, silica or a double oxide thereof. The image forming method according to any one of the above. 8. The image forming method according to claim 1, wherein the inorganic fine powder contained in the toner has been subjected to a hydrophobic treatment. 9. The image forming method according to claim 8, wherein the hydrophobic inorganic fine powder contained in the toner has been treated with at least silicone oil. 10. The toner according to claim 1, wherein the low-molecular-weight polyethylene is
The image forming method according to claim 1, further comprising at least one of a low molecular weight hydrocarbon wax and a higher alcohol. 11. The toner has a specific surface area (BET) of 0.1.
The image forming method according to claim 1, wherein the amount is 9 to 1.3 m ² / g. 12. The toner has a shape factor SF-1 value measured by an image analyzer of 110 <SF-1 ≦ 180 and a shape factor SF-2 value of 110 <SF-2 ≦ 140.
And a value B obtained by subtracting 100 from the value of SF-2 and SF-
The value of the ratio B / A to the value A obtained by subtracting 100 from the value of 1 is 1.
The image forming method according to claim 1, wherein the value is 0 or less.