JP2006343379A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set proper cleaning device replacement time according to the conditions of a belt to be cleaned when it is made possible to replace only a cleaning device so as to reduce CPP. <P>SOLUTION: In the detachable cleaning device for removing residual toner on a surface of an intermediate transfer member used in an image forming apparatus, the residual toner is minute toner and the cleaning device has a shorter lifetime than the intermediate transfer member and has a setting means to set replacement time of the cleaning device according to the surface conditions of the intermediate transfer member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning apparatus and an image forming apparatus such as a copying machine, a printer, and a fax machine, and more particularly to an improved invention for cleaning an intermediate transfer member used in the image forming apparatus.

  As a conventional intermediate transfer type image forming apparatus, there is little variation in cleaning performance even when the environmental conditions change from high temperature to low temperature, and the friction coefficient with the photoconductor is reduced to improve the cleaning performance by the cleaning blade. An apparatus having a cleaning device for preventing the occurrence of image defects based on an additive such as silica has been proposed (for example, see Patent Document 1).

  The toner image formed on the photoconductor is primarily transferred to the above-described intermediate transfer belt and then secondarily transferred onto a recording medium to form a color image. After the secondary transfer, the toner image remaining on the intermediate transfer belt is cleaned by a cleaning device.

  Known cleaning devices include a method of physically scraping off toner with a cleaning blade and a method of electrostatically removing residual toner using a brush roller.

By the way, in recent years, due to the demand for higher image quality and the like, toner having a smaller particle size or a spherical polymerized toner has been used, and it has become increasingly difficult to clean the toner remaining on the belt. ing. For this reason, there are many cases in which the life of the cleaning device must be set to be shorter than that of other units. Furthermore, in order to reduce CPP (cost per print), there is an increasing demand for a configuration in which the cleaning unit can be replaced separately from other units.
JP 2004-117458 A

  In general, the life of a cleaning blade varies depending on the state of an object with which the blade is in contact. For example, when the surface of the object is rough, there is a problem in that the amount of wear of the cleaning blade increases, resulting in a short life. In addition, when the surface friction coefficient of the object is large, there is a problem that the dynamic pressure of the blade edge increases and the blade edge is chipped.

  The present invention has been made in consideration of the above-described circumstances. When the cleaning device can be replaced independently for the purpose of reducing the CPP, an appropriate cleaning device replacement time is determined according to the state of the belt to be cleaned. The purpose is to be able to set.

  In order to solve the above problems, the invention according to claim 1 is a removable cleaning device for removing residual toner on the surface of an intermediate transfer member used in an image forming apparatus, wherein the residual toner is a fine toner. The cleaning device has setting means for setting a replacement time of the cleaning device in accordance with the surface state of the intermediate transfer member, which is shorter than the life of the intermediate transfer member.

  According to a second aspect of the present invention, in the first aspect, the setting means sets the replacement time based on information on a belt surface roughness.

  According to a third aspect of the present invention, in the first aspect, the setting means sets the replacement time based on information on a belt surface friction coefficient.

  According to a fourth aspect of the present invention, in the second aspect, the belt surface roughness is obtained by using an optical sensor.

  According to a fifth aspect of the present invention, in the third aspect, the belt surface friction coefficient is obtained using a belt driving torque.

  According to a sixth aspect of the present invention, the image forming apparatus includes the cleaning device according to any one of the first to fifth aspects.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, the toner used in the image forming apparatus has a volume average particle diameter in the range of 3 to 8 μm and a volume average particle diameter (Dv). And the number average particle diameter (Dn) (Dv / Dn) is in the range of 1.00 to 1.40.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the sixth aspect, the toner 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. It is characterized by being.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the sixth aspect, the toner used in the developing means is at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. A toner obtained by crosslinking and / or extending a toner material liquid in which an agent is dispersed in an organic solvent in an aqueous medium.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the sixth aspect, the toner has a substantially spherical shape.

  According to an eleventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, the shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (provided that r1 ≧ r2 ≧ r3). ), The ratio of the major axis r1 to the minor axis r2 (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness r3 to the minor axis r2 (r3 / r2) is 0.7 to It is characterized by being in the range of 1.0.

  The apparatus according to claims 7 to 11 uses a polymerized toner or SPR-C toner as the toner used in the image forming apparatus. When the toner is a polymerized toner or SPR-C toner, the shape thereof is close to a sphere and has a small particle size, so cleaning with a blade is particularly difficult, and slight blade wear with time and deterioration of the surface condition of an object are difficult. But the cleaning performance is reduced. Therefore, it is considered effective to have a means for setting an appropriate cleaning life depending on the belt surface condition.

  According to the present invention, it is possible to set an appropriate replacement time for the cleaning device in accordance with the surface state of the intermediate transfer member that is the object of the cleaning device.

Hereinafter, a cleaning device and an image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of an electrophotographic apparatus of a tandem type indirect transfer system to which the present invention is applied. The copying machine main body is provided with an endless belt-like intermediate transfer member 11 at the center. The intermediate transfer body 11 has a multilayer structure, and the base layer is made of, for example, a fluororesin, PVD sheet, or polyimide resin with little elongation, and the surface is covered with a smooth coat layer such as a fluororesin. As shown in FIG. 1, the intermediate transfer body 11 is wound around the support rollers 10, 12, 34, and 35 and can be rotated counterclockwise as indicated by → (arrow).

On the left side of the support roller 10, an intermediate transfer body cleaning device 25 that removes residual toner remaining on the intermediate transfer body 11 after image transfer is provided. Further, on the intermediate transfer member 11 stretched between the support roller 12 and the support roller 35, four image forming units indicated by a, d, black, yellow, magenta, and cyan are horizontally arranged along the conveyance direction. A tandem image forming apparatus is arranged side by side.
A fixing device 30 for fixing the transferred image on the sheet is provided on the secondary transfer device. The fixing device 30 is configured by pressing a pressure roller against a fixing roller.

  As shown in FIG. 1, an exposure device 4 is further provided below the tandem image forming apparatus. On the other hand, a secondary transfer device is provided on the side of the intermediate transfer body 11 facing the support roller 35. In the illustrated example, the secondary transfer device is configured by spanning a secondary transfer belt 100, which is an endless belt, between two rollers 111 and 112, and is pressed against the support roller 35 via the intermediate transfer body 11. Then, the image on the intermediate transfer body 11 is transferred to a sheet. The secondary transfer device is not limited to such an embodiment, and there is also a device using a secondary transfer roller 36 (see, for example, FIG. 2). In addition, when the code | symbol attached | subjected to FIG. 2 is the same as FIG. 1, the code | symbol of FIG. 1 was used.

A fixing device 30 for fixing the transferred image on the sheet is provided above the secondary transfer device. The fixing device 30 is configured by pressing a pressure roller against a fixing roller.
The secondary transfer device described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device 30. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device.

  The operation of the tandem indirect transfer type electrophotographic apparatus to which the present invention is applied will be described below. When a start switch (not shown) is pressed, one of the support rollers 10, 34, and 35 is rotationally driven by a drive motor (not shown), the other four support rollers are also driven to rotate, and the intermediate transfer member 11 rotates. At the same time, the photosensitive member 1 is rotated by individual image forming means to form black, yellow, magenta, and cyan single-color images on each photosensitive member 1, respectively. Then, along with the conveyance of the intermediate transfer member 11, the single color images are sequentially transferred to form a composite color image on the intermediate transfer member 11.

  On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 27 of the paper feed table is selectively rotated, the sheet is fed out from one of the paper feed cassettes 26 provided in multiple stages in the paper bank, and one sheet is fed by the separation roller. The paper is separated and put into the paper feed path 29, transported by a transport roller, guided to the paper feed path 29 in the copying machine main body, and abutted against the registration roller 28 and stopped.

  On the other hand, one of the paper feed rollers 27 of the paper feed table is selectively rotated, the sheets are fed out from one of the paper feed cassettes 26-1 to 26-n provided in the paper bank in multiple stages, and separated one by one by the separation roller 27. Then, the sheet is conveyed to the paper feed path 29 and stopped by abutting against the registration roller 28. Next, the registration roller 28 is rotated in time with the composite color image on the intermediate transfer body 11, the sheet is fed between the intermediate transfer body 11 and the secondary transfer device, and is transferred on the sheet by the secondary transfer device. Record a color image on

  Further, the image-transferred sheet is conveyed by the secondary transfer device and sent to the fixing device 30. The fixing device 30 applies heat and pressure to fix the transferred image, and then is discharged by the discharge roller 32. The paper is discharged onto the paper discharge tray 40.

  After the transfer, the intermediate transfer body 11 removes residual toner remaining on the intermediate transfer body 11 after the image is transferred by the intermediate transfer body cleaning device 25, and prepares for the image formation again by the tandem image forming apparatus.

  The cleaning device of the present invention will be described below. In FIG. 2, the support roller 10 is a cleaning counter roller, and is provided with an intermediate transfer body cleaning device 25 that opposes the support roller 10 and removes residual toner remaining on the intermediate transfer body 11 after image secondary transfer. In this configuration, the cleaning counter roller 10 also serves as a tension roller, and functions to apply a constant tension to the intermediate transfer belt 11. Four rollers 20 are primary transfer rollers, and four rollers 20 are provided corresponding to black, yellow, magenta, and cyan image forming means.

  In the present invention, the intermediate transfer member cleaning device 25 is detachable. In the cleaning device, there may be a case where the lifetime of the cleaning blade is shorter than that of the intermediate transfer belt as shown in FIG. In such a case, the intermediate transfer belt is continuously used as it is, and only the cleaning blade is replaced with a new one. However, in this case, since the state of the belt is different from that of a new belt, it is considered that the expected blade life is not the same as when both the belt and the blade are started from a new one. In general, since the belt is worn over time or the surface of the belt becomes rough due to adhesion of foreign matter, it is considered that the blade has a shorter life compared to the case of starting from a new belt. Therefore, in the present invention, according to the surface condition of the belt when the cleaning means is replaced, the service life of the cleaning means is appropriately set by multiplying the life when both are started from a new one by the correction coefficient α (α <1). Like that. However, since this correction coefficient varies depending on the type of toner, belt, blade, and machine specifications, it must be determined experimentally.

  As for what actually changes in the belt surface state, surface roughness, surface friction coefficient, etc. can be considered. As shown in FIG. 4, when the surface roughness of the belt is rough, the load on the blade edge increases, so that blade wear is promoted. In addition, since the object having a rough surface is considered to be disadvantageous for the cleaning property, the life of the blade must be set short. Further, when the friction coefficient of the belt is different as shown in FIG. 5, if the surface friction coefficient of the belt is large, the amount of the blade edge that is pulled in increases, so the local pressure of the blade edge increases, Chipping is likely to occur. Also, if the friction coefficient of the belt is large, it is difficult to separate the toner from the surface of the belt, and the cleaning property is also deteriorated. Therefore, the blade replacement time must be set early. Therefore, the belt surface roughness or surface friction coefficient at the time of cleaning means replacement is detected, and the next cleaning means replacement time is determined based on the information.

  As a method of detecting the surface roughness of the belt, a method of measuring the regular reflectance and glossiness of the belt using an optical sensor can be used. As the surface of the belt becomes rough, the regular reflectance and the glossiness decrease, so that the surface roughness of the belt can be converted. Therefore, the inventors have devised that the regular reflection rate and glossiness of the belt when the cleaning means is replaced are detected, and the next cleaning means replacement time is set based on the detected information. Since an optical sensor is usually mounted for image adjustment, it is not necessary to add a detection means specially for this purpose.

  As a method for detecting the surface friction coefficient of the belt, a method using the driving torque of the belt has been devised. FIG. 6 shows a case where the friction coefficient of the belt increases with time. When the surface friction coefficient of the belt increases, the load on the blade increases, so it is considered that the drive torque immediately after replacement with a new blade increases. Therefore, the next blade replacement time is set based on the belt driving torque immediately after the cleaning means replacement. Since the belt driving torque can be detected by measuring the current value of the motor driving the belt, it is not necessary to add a special detecting means.

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.

It is preferable that the toner 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. 7 and 8 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} * (100 [pi] / 4) .. Formula (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.
It is preferable that at least a part of the unmodified polyester and the urea-modified polyester are compatible and the 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 ortho nitro Nirin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, 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, Toulouse 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, Thioindigo Red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo 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, Phthalo Cyanine 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 salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. 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 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), 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, a high-speed shearing type 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. 9 is a diagram schematically showing the shape of the toner used in the image forming apparatus of the present invention. In FIG. 9, 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. 9B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 9C) is 0.7 to 1.0. 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 the separation from the true spherical shape, and high quality image quality cannot be obtained. On the other hand, when the ratio of the thickness to the short axis (r3 / r2) is less than 0.7, it becomes 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.

It is a figure which shows an example of the image forming apparatus provided with the cleaning apparatus of this invention. FIG. 2 is a schematic diagram illustrating a cleaning device (cleaning unit) in a state of being mounted on an intermediate transfer unit used in the image forming apparatus. It is a figure which shows the example which calculates | requires the replacement | exchange time of the cleaning blade currently used for the cleaning unit by (alpha) which is at least one of information (belt surface roughness information and belt surface friction coefficient information) (in the figure, α1, α2, ... Is obtained in time series. It is a figure showing that the life of the cleaning blade used in the cleaning unit is affected by the surface roughness of the transfer belt. It is a figure showing that the life of the cleaning blade used in the cleaning unit is affected by the surface friction coefficient of the transfer belt. It is a figure for calculating | requiring the lifetime (replacement time) of the cleaning blade currently used for the cleaning unit, and is a figure for estimating replacement time based on a transfer belt drive torque (a horizontal axis is transfer belt image formation frequency ( KD), and the vertical axis represents the transfer belt driving torque (blade load). FIG. 6 is a diagram for explaining a relationship between MXLNG (maximum diameter) of toner and SF-1. FIG. 6 is a diagram for explaining SF-2 from the PERI of toner and the area of the PERI of the toner. 4A and 4B are diagrams for explaining r1, r2, and r3 of toner, where FIG. 5A shows a coordinate system with the center of the toner as the origin, and FIG. 5B shows the arrangement of the toner as shown in FIG. FIG. 6 is a diagram for explaining that r1, r2, and r3 are obtained by projecting onto the xy plane and the zy plane after the calculation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 10 Cleaning counter and tension roller 11 Transfer belt 12 (Left) Driven roller 20 Primary transfer roller 25 Cleaning unit (cleaning device)
35 (Right) Driven roller

Claims (11)

In a detachable cleaning device for removing residual toner on the surface of an intermediate transfer member used in an image forming apparatus,
The residual toner is a fine toner,
The cleaning device is characterized in that the cleaning device has a setting means for setting the replacement time of the cleaning device in accordance with the surface state of the intermediate transfer member, which is shorter than the life of the intermediate transfer member.   The cleaning device according to claim 1, wherein the setting unit sets the replacement time based on belt surface roughness information.   The cleaning device according to claim 1, wherein the setting unit sets the replacement time based on information on a belt surface friction coefficient.   The cleaning apparatus according to claim 2, wherein the belt surface roughness is obtained using an optical sensor.   4. The cleaning apparatus according to claim 3, wherein the belt surface friction coefficient is obtained by using a belt driving torque.   An image forming apparatus comprising the cleaning device according to claim 1.   7. The image forming apparatus according to claim 6, wherein the toner used in the image forming apparatus has a volume average particle diameter in a range of 3 to 8 [mu] m, and a volume average particle diameter (Dv) and a number average particle diameter (Dn). The ratio (Dv / Dn) is in the range of 1.00 to 1.40.   7. The image forming apparatus according to claim 6, wherein the toner 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. .   7. The image forming apparatus according to claim 6, wherein at least the polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. An image forming apparatus, which is a toner obtained by crosslinking and / or extending a toner material liquid in an aqueous medium.   The image forming apparatus according to claim 6, wherein the toner has a substantially spherical shape. The image forming apparatus according to claim 6.
The shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and the ratio (r2 / r1) between the major axis r1 and the minor axis r2 is 0. An image forming apparatus having a thickness in the range of 5 to 1.0 and a ratio of the thickness r3 to the minor axis r2 (r3 / r2) in the range of 0.7 to 1.0.

Images