JP2009020212A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To apply a lubricant in a proper quantity, to restrain an abnormal image such as a texture soiling when restarted after stopped, and to keep stable image quality over a long period. <P>SOLUTION: This image forming device has a counting means for counting a stop time of a developing device (stop times of a photoreceptor and a device main body are included as the same meaning), and ON-/OFF-timing for rotation of a bristle raising member (brush roller) of a lubricant applying means is controlled by a count value counted by the counting means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, a plotter, and a multifunction machine having at least one of them.

In Patent Document 1, the brush hair density of the lubricant application member is 20,000 / 645.16 mm 2 or more, the rotation speed of the lubricant application member is R, and the surface of the image carrier of the brush of the lubricant application member is returned. By satisfying 55 rpm ≦ R ≦ 220 rpm, 0 mm <δ ≦ 1 mm, 0 mN <P ≦ 400 mN, where δ is the amount of biting and P is the pressure at which the solid lubricant contacting the brush contacts the brush It describes that the uniformity of the coating amount of the lubricant applied to the surface of the image carrier is improved.
Patent Document 2 discloses a lubricant application unit that is arranged so as to be able to come into contact with and separate from a photoconductor or a transfer medium, and intermittently applies a lubricant to the photoconductor or the transfer medium, and a modification of the application unit. The movement control means for controlling the movement direction of the lubricant application means to correct the lubricant, and the contact state of the lubricant application means is restored by moving the movement direction of the application means in the direction opposite to that during application. And a technique for always supplying a stable lubricant.
Patent Document 3 discloses a developing unit that develops a latent image on a photoconductor, a cleaning brush that cleans the photoconductor, a coating unit that applies a lubricant to the surface of the photoconductor, a reference toner image and a background on the photoconductor. An image forming unit that forms a portion of the image, a detection unit that detects a reference toner image and a background density on the photosensitive member, and a reference toner image and a background density value detected by the detection unit of the image forming apparatus. It is described that a high-quality image is obtained by providing a control means for controlling the amount of lubricant applied.

Japanese Patent Laid-Open No. 10-260614 Japanese Patent Laid-Open No. 7-334058 JP-A-8-137354 JP 56-154778 A

  Conventionally, an image carrier that forms a toner image on the surface while being rotated, a transfer device that transfers the toner image to a transfer material, and a transfer residual toner that adheres to the surface of the image carrier after the toner image is transferred is removed. An image comprising: a cleaning member that cleans the surface of the image carrier; and a lubricant application member that has a brush that contacts the surface of the image carrier and applies a lubricant to the surface of the image carrier while being driven to rotate. A forming apparatus is known, and is configured as a copying machine, a printer, a facsimile, or a multifunction machine having at least two of these functions (see Patent Document 4).

According to this type of image forming apparatus, since the lubricant is applied to the surface of the image carrier, the coefficient of friction with respect to the toner on the surface of the image carrier can be reduced, whereby the toner formed on the surface of the image carrier. It is possible to suppress the occurrence of transfer failure when the image is transferred to the transfer material, and to improve the image quality of the transferred toner image.
In particular, it is possible to suppress the occurrence of a character part dropout phenomenon in which a part of a character image is lacking in a worm-like shape and improve the image quality. Further, it has the effect of preventing toner filming on the surface of the image carrier and suppressing the abrasion of the surface layer, and contributes to the life of the image carrier on the hard surface.
However, when a lubricant is applied to the surface of the image carrier, the coefficient of friction with respect to the toner on the surface decreases, so if the amount of lubricant applied to the surface of the image carrier becomes non-uniform, the unevenness of the application causes the image carrier to become uneven. The toner adhesion amount of the toner image formed on the surface becomes non-uniform, uneven density occurs in the toner image, and the image quality deteriorates.
That is, the amount of toner attached to the surface of the image carrier with a large amount of lubricant applied decreases, and conversely, a large amount of toner adheres to the portion with a small amount of lubricant applied, resulting in uneven density in the toner image. Will occur. In particular, uneven density tends to occur in a low-density toner image.

Therefore, various configurations for making the amount of lubricant applied uniformly to the surface of the image carrier have been proposed, and a lubricant application brush has been studied, but the configuration of the image forming apparatus is complicated, It was accompanied by the disadvantage that the cost increased.
In recent years, as charging means for an image forming process in electrophotography, a charging device in which a charging member is disposed in contact with or in proximity to a photoconductor to perform charging processing has been widely adopted. However, AC is applied to the charging member. In this case, the amount of ozone generated is smaller than that of the corona charger, but there is an adverse effect due to the discharge product.
That is, the discharge product, toner, and toner additive are fused and adhered to the photoconductor surface (commonly known as photoconductor filming), so that the surface of the photoconductor is lowered and the resolution of the latent image is reduced. Decrease, and blur and image flow are likely to occur.
This impairs the smoothness of the surface of the photosensitive member, induces poor cleaning of the photosensitive member, and makes the quality with time unstable. Therefore, it has been proposed to apply a lubricant to protect the surface of the photoreceptor. However, if the amount of application is increased, excess lubricant will contaminate the charging member, causing charging failure and reliability of quality over time. It was damaging.

In the case of development, the toner that is a developer is charged with stirring during operation, saturated and stabilized at a predetermined value, and goes out of the developing device by image formation, but continues to remain in the developing device. There is also. The toner is charged by stirring and gradually discharged when stopped without stirring. However, the toner remaining in the developing device (residual toner) becomes smaller in charge amount due to repeated charging and discharging. The charging ability is deteriorated.
Therefore, at the time of re-operation after being stopped without being stirred for a long time, the staying toner is discharged from the developing device at a stretch due to the difference in charge amount from the newly replenished toner (fresh toner), and is transferred to the photoreceptor. It has been confirmed that the adherent background stain phenomenon occurs.
If this level is poor, the output image on the paper will also be stained, and even if it does not appear on the paper, repeating this phenomenon places a burden on the photoconductor cleaning (for example, blade wear if using the blade method). Promotes a decrease in reliability over time.

  The present invention has been made in view of the above problems, and with a relatively simple and low-cost configuration, the amount of lubricant applied to the surface of the image bearing member can be efficiently and uniformly ensured. It is an object of the present invention to provide an image forming apparatus of the type described at the beginning which is unlikely to cause side effects.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a rotating image carrier, and a rotatable raising member disposed in contact with the image carrier and applying a lubricant to the image carrier. And a lubricant application means in which the raised member is always in contact with the lubricant, and a charging device that is disposed in contact with or in close proximity to the image carrier and that performs a charging process by applying a bias superimposed with AC. In an image forming apparatus having a member and a developing device that stores a developer that visualizes a latent image formed on the image carrier, a stop time of the developing device (a stop time of the photoconductor and the apparatus main body) And a control means for controlling the ON / OFF timing of the rotation of the raising member of the lubricant applying means according to the count value counted by the counting means. To.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the control means sets the ON / OFF timing of the rotation of the raising member at least for a time T1 required for one rotation of the image carrier. It is characterized in that it is variably controlled with a duty ratio where the time T2 that does not become an integer ratio is 100%.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the rotating operation of the raising member is turned off at least when the image carrier is not rotating.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the charging member, the developing device, a cleaning device for cleaning the surface of the image carrier, and the lubricant application At least one of the means and the image carrier are integrally provided, and a process cartridge that can be attached to and detached from the main body of the image forming apparatus is provided.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner used in the developing device has a volume average particle diameter of 3 to 8 μm and a volume average particle diameter ( The ratio (Dv / Dn) of Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.40.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner used in the developing device has a shape factor SF-1 in the range of 100 to 180, and has a shape. The coefficient SF-2 is in the range of 100 to 180.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner used in the developing device is a polyester prepolymer or polyester having a functional group containing at least a nitrogen atom. The toner is obtained by crosslinking and / or stretching reaction of a toner material liquid in which a colorant and a release agent are dispersed in an organic solvent in an aqueous medium.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner used in the developing device has a substantially spherical shape.

According to the present invention, since the lubricant can be applied without excess or deficiency, abnormal images such as background stains that are restarted after stopping can be suppressed, and stable image quality can be maintained over the long term.
The application amount can be variably controlled without impairing the uniformity of the lubricant application amount in the circumferential direction of the image carrier. Further, it is possible to prevent excessive application of the lubricant to a specific portion of the image carrier. It is possible to improve exchange and maintenance.
In addition, the transfer rate of the toner image can be increased.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the present embodiment. The image forming apparatus includes an intermediate transfer belt 56 in the approximate center of the inside thereof. The intermediate transfer belt 56 is an endless belt made of a heat-resistant material such as polyimide or polyamide and made of a base adjusted to a medium resistance, and is supported by being wound around four rollers 52, 53, 54, and 55. It is rotationally driven in the direction of arrow A.
Below the intermediate transfer belt 56, four image forming units corresponding to yellow (Y), magenta (M), cyan (C), and black (K) toners are arranged along the belt surface of the intermediate transfer belt 56. It is out.

FIG. 2 is an enlarged view showing one of four image forming units (process cartridges), which is basically the same as the configuration of a conventional coating apparatus. Since any image forming unit has the same configuration, Y, M, C, and K indicating color distinction are omitted in this figure.
Each image forming unit has photoconductors 1Y, 1M, 1C, and 1K as image carriers. Around each photoconductor 1, a charging device 2 for applying a charge to the surface of the photoconductor 1 is formed on the surface of the photoconductor 1. The developed latent image is developed with each color toner to form a toner image, a developing device 4, a lubricant applying device 3 as a lubricant applying means for applying a lubricant to the surface of the photosensitive member 1, and the surface of the photosensitive member 1 after transferring the toner image. Each of the cleaning devices 8 for cleaning is provided.

Referring to FIG. 1, below the four image forming units, there is provided an exposure device 9 that exposes the surface of each charged photoconductor based on image data of each color to form a latent image. .
A primary transfer roller 51 that primarily transfers a toner image formed on the photoconductor 1 onto the intermediate transfer belt 56 is disposed at a position facing each photoconductor 1 with the intermediate transfer belt 56 interposed therebetween. The primary transfer roller 51 is connected to a power source (not shown) and is applied with a predetermined voltage.
A secondary transfer roller 61 is pressed against the outside of the portion of the intermediate transfer belt 56 supported by the roller 52. The secondary transfer roller 61 is connected to a power source (not shown) and is applied with a predetermined voltage. A contact portion between the secondary transfer roller 61 and the intermediate transfer belt 56 is a secondary transfer portion, and the toner image on the intermediate transfer belt 56 is transferred onto a transfer sheet.

An intermediate transfer belt cleaning device 57 for cleaning the surface of the intermediate transfer belt 56 after the secondary transfer is provided outside the portion of the intermediate transfer belt 56 supported by the roller 55.
Above the secondary transfer portion, a fixing device 70 is provided that fixes the toner image on the transfer paper semi-permanently to the transfer paper. The fixing device 70 includes a heating roller 72 having a halogen heater therein and an endless fixing belt 71 wound around the fixing roller 73, and a pressurization disposed so as to be opposed to and in pressure contact with the fixing roller 73 via the fixing belt 71. And a roller 74.
Below the image forming apparatus, there is provided a paper feeding device 20 for placing the transfer paper and feeding the transfer paper toward the secondary transfer unit.

Next, the features of the image forming apparatus will be described in more detail with reference to FIG.
The photoreceptor 1 is an organic photoreceptor, and a surface protective layer is formed of a polycarbonate-based resin.
The charging device 2 includes a charging roller 2a configured by covering a conductive cored bar with a medium resistance elastic layer as a charging member. The charging roller 2a is connected to a power source (not shown) and is applied with a predetermined voltage.
The charging roller 2a is disposed in close proximity to the photoreceptor 1 with a small gap. The minute gap is set by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 2a to bring the surface of the spacer member into contact with the surface of the photoreceptor 1. can do.
Further, the charging roller 2a is provided with a charging cleaning member 2b for cleaning in contact with the surface of the charging roller 2a.

In the developing device 4, a developing sleeve 4 a provided with a magnetic field generating unit is disposed at a position facing the photoconductor 1. Below the developing sleeve 4a, there are provided two screws 4b for mixing toner introduced from a toner bottle (not shown) with the developer and pumping it up to the developing sleeve 4a while stirring.
The developer composed of toner and magnetic carrier pumped up by the developing sleeve 4a is regulated to a predetermined developer layer thickness by the doctor blade 4c and is carried on the developing sleeve 4a. The developing sleeve 4a carries and conveys the developer while moving in the same direction at a position facing the photoconductor 1, and supplies toner to the latent image surface of the photoconductor 1.

The lubricant application device 3 includes a solid lubricant 3b as a lubricant accommodated in a fixed case, and a brush roller as a raised member that contacts the solid lubricant 3b to scrape off the lubricant and apply it to the photoreceptor 1. 3a.
The solid lubricant 3b is formed in a rectangular parallelepiped shape and is urged toward the brush roller 3a by the pressure member 3c. The pressurizing member 3c is preferably a spring such as a leaf spring or a compression spring, and a compression spring can be preferably used as shown in the drawing.
The solid lubricant 3b is scraped off and consumed by the brush roller 3a, and the thickness of the solid lubricant 3b decreases with time. However, since the solid lubricant 3b is pressurized by the pressure member 3c, it is always in contact with the brush roller 3a. The brush roller 3 a applies the lubricant scraped off while rotating to the surface of the photoreceptor 1.

Brush thickness of the fibers of the brush roller 3a is preferably 3 to 8 deniers, the density of the brush fibers 20000-100000 present / inch ² is preferable. If the thickness of the brush fiber is too thin, the brush roller 3a is liable to fall down when the brush roller 3a comes into contact with the surface of the photoconductor 1. Conversely, if the brush fiber is too thick, the density of the fiber cannot be increased.
In addition, if the density of the brush fibers is low, the number of brush fibers in contact with the surface of the photoreceptor 1 is small, so that the lubricant cannot be uniformly applied. The gap becomes small, and the amount of the lubricant powder that has been scraped off decreases, resulting in an insufficient amount of coating.
Therefore, the brush roller 3a having the above-described setting range has the thickness of the brush fiber for preventing the hair from collapsing and the density of the brush fiber capable of efficiently applying the lubricant uniformly.

As the solid lubricant 3b, a dry solid hydrophobic lubricant can be used. Besides zinc stearate, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, Those having a stearic acid group such as copper stearate, strontium stearate, calcium stearate, cadmium stearate and magnesium stearate can be used. In addition, the same fatty acid groups zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, and palmitic acid, zinc cobalt palmitate, copper palmitate, palmitate Magnesium acid, aluminum palmitate, and calcium palmitate may be used. In addition, fatty acids such as lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate and cadmium ricolinolenate, metal salts of fatty acids, and the like can also be used.
Further, waxes such as candelilla wax, carnauba wax, rice wax, wax, ooba oil, beeswax, and lanolin can be used.

In the present embodiment, a cleaning blade 8a as a cleaning unit is brought into contact with the surface of the photoreceptor downstream in the moving direction with respect to a lubricant application position by the brush roller 3a and functions as a lubricant leveling unit. I have it.
The cleaning blade 8a is made of rubber which is an elastic body.

FIG. 3 shows a timing chart of a motor which is a drive source of the brush roller 3a as a lubricant application brush, and a clutch for transmitting rotation from the drive source (motor) to the brush roller 3a.
The clutch ON is to apply a lubricant on the surface of the photoreceptor. When a lubricant is applied, the coefficient of friction with respect to the toner on the surface is reduced. Therefore, if the amount of lubricant applied to the surface of the photoconductor becomes non-uniform, the unevenness of the application causes a toner image formed on the surface of the photoconductor. The toner adhesion amount becomes non-uniform, density unevenness occurs in the toner image, and the image quality deteriorates.
The amount of toner adhering to the surface of the image carrier with a large amount of lubricant applied decreases, and conversely, a large amount of toner adheres to the portion with a small amount of lubricant applied, resulting in uneven density in the toner image. To do. In particular, uneven density tends to occur in a low-density toner image.

Therefore, since at least the rotation of the brush roller 3a needs to be turned off when the photosensitive member is stopped, in this embodiment, the drive source (drive motor) of the brush roller 3a is a developing motor related to image formation. Of course, the developing motor is stopped when the photosensitive member is not driven.
In this embodiment, the ON time: X in the clutch timing chart is a% display when the time T2 (0.797 sec.) Required for the photoreceptor to make 1.3 turns is 100.
The circumferential length of the photosensitive drum is φ40 mm = 125.66 mm, and the time T1 required for one round is a linear velocity of 205 mm / sec. And 0.613 sec. It is.

The ON time: X can be varied from 0 to 100. For example, if X = 100, the clutch remains ON (brush rotation ON).
If X = 60, the ON time is 0.797 × 0.6 = 0.478 sec. , OFF time 0.797 × 0.4 = 0.319 sec. Is repeated.
By setting T2 to a time that does not become an integer ratio with respect to the time required for one rotation of the photosensitive member, it is possible to apply at random to the entire circumference without applying a specific portion in the circumferential direction.
When the time T2 is set to a time corresponding to a circumference that does not become an integer even if it is doubled, quadrupled, or fivefold, like the time required for the photosensitive member 1.3 rounds as in the present embodiment, it is more effective. Is expensive. For example, in addition to 1.3 laps in the present embodiment, 1.1 laps, 1.7 laps, 1.9 laps, or the like. The value of X can be set independently for each color image forming unit.

In this embodiment, even if the ease of toner adhesion to the photoconductor changes depending on the stop time of the developing device, the amount of toner adhering to the photoconductor is limited by variably controlling the ON time: X of the brush roller 3a. The following is effective. The variable control is performed by control means (microcomputer) (not shown).
When the developing device stops, the control unit issues a time measurement command to a timer (not shown) as a counting unit and acquires a count value. Based on this count value, the ON / OFF timing of the rotation of the brush roller 3a is controlled.
Here, the stop time of the developing device is counted, but the stop time of the photosensitive member and the apparatus main body is also synonymous.

In order to confirm the effect of the present invention, first, the density measurement of the background portion on the photoreceptor when the ON time: X was varied was performed every time the developing device was stopped. The developing device used reached about 1/3 of the device life.
The density measuring instrument uses a spectrophotometric densitometer (model 938) manufactured by X-Rite, and an image formed on the photoconductor is adhesive-transferred with a transparent tape and pasted on a blank sheet. A density measurement is performed on a non-existing portion (background portion), and a difference between the value and a concentration obtained by sticking a tape on which nothing is adhesively transferred to a white paper is defined as a characteristic value ΔID, and 0.01 or less is allowed. The measurement results are shown in FIG.

As described above, the effect of suppressing the background stain after stopping by changing the ON time: X was confirmed.
Based on the above results, actual use evaluation was performed with a machine that controlled the ON time: X with respect to the stop time. As a result, there was no background stain after the stop or charging failure over time, and stable image quality was obtained over the long term. I was able to confirm that.
Further, since the lubricant application operation needs to be turned off at least when the photosensitive member is stopped, in this embodiment, the driving of the brush roller 3a is set in synchronization with the photosensitive member driving.

Next, the toner suitably used in the image forming apparatus of the present invention will be described.
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. 5 and 6 are diagrams schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2.
The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100π / 4) Expression (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.
When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

The toner suitably used in the image forming apparatus of the present invention includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.
(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound. Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable.
Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts.

Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use.
The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred.
Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid).
Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20.
By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.
The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.
Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.
The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).
Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.
Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.
Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.
The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.
The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group.

Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.
When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).
In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.
By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition. The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.
The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.
In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salt or compound, tungsten simple substance or compound, fluorine activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like.
Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used.
Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 −3 to 2 μm, and particularly preferably 5 × 10 −3 to 0.5 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m <2> / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle size of 5 × 10-2 μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. .
Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if
Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.
Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).
Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.).
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

  3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group. This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

The toner according to the present invention has a substantially spherical shape and can be represented by the following shape rule.
FIG. 7 is a diagram schematically showing the shape of the toner of the present invention. In FIG. 7, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present invention has a major axis and a minor axis. Ratio (r2 / r1) (see FIG. 7B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 7B) is 0.7 to It is preferable to be in the range of 1.0.
When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained.
In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.
Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a block diagram of a process cartridge. 4 is a timing chart of a lubricant application brush drive source and a clutch for transmitting rotation from the drive source to the lubricant application brush. It is a graph which shows the relationship between the difference characteristic value of a density | concentration, and ON time. FIG. 4 is a diagram schematically illustrating the shape of a toner for explaining a shape factor SF-1. FIG. 6 is a diagram schematically illustrating the shape of a toner for explaining a shape factor SF-2. It is a figure which shows typically the shape of the toner of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor as image carrier 2a Charging roller as charging member 3 Lubricant application device as lubricant applying means 3a Brush roller as raising member 3b Solid lubricant as lubricant 4 Developing device 8 Cleaning device

Claims (8)

A rotating image carrier;
A lubricant application means that is arranged in contact with the image carrier, includes a rotatable raising member that applies a lubricant to the image carrier, and the raising member is always in contact with the lubricant;
A charging member that is disposed in contact with or in close proximity to the image carrier and that performs a charging process by applying a bias superimposed with AC;
A developing device containing a developer for visualizing a latent image formed on the image carrier;
In an image forming apparatus having
A counting unit that counts a stop time of the developing device, and a control unit that controls ON / OFF timing of rotation of the raising member of the lubricant applying unit according to a count value counted by the counting unit. An image forming apparatus. The image forming apparatus according to claim 1.
The control means variably controls the ON / OFF timing of the rotation of the raising member at a duty ratio where the time T2 that is not at least an integer ratio of the time T1 required for one rotation of the image carrier is 100%. An image forming apparatus. The image forming apparatus according to claim 1 or 2,
The image forming apparatus according to claim 1, wherein the rotating operation of the raising member is turned off at least when the image carrier is not rotating. The image forming apparatus according to any one of claims 1 to 3,
A process that integrally includes at least one of the charging member, the developing device, a cleaning device that cleans the surface of the image carrier, and the lubricant application unit and the image carrier, and is detachable from the image forming apparatus main body. An image forming apparatus having a cartridge. The image forming apparatus according to any one of claims 1 to 4,
The toner used in the developing device has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1.40. An image forming apparatus characterized by being in the range. The image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus according to claim 1, wherein the toner used in the developing device has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. The image forming apparatus according to any one of claims 1 to 4,
The toner used in the developing device is obtained by crosslinking a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous medium. And / or an image forming apparatus, wherein the toner is obtained by an extension reaction. The image forming apparatus according to any one of claims 1 to 4,
An image forming apparatus, wherein the toner used in the developing device has a substantially spherical shape.

Images