JP2005249896A - Image forming apparatus and toner used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a small amount of toner passing through over a photoreceptor or little buckling of a cleaning blade during cleaning by detecting the relation between a cleaning device and a photoreceptor and controlling the cleaning conditions. <P>SOLUTION: The image forming apparatus 1 is equipped with a detecting means which detects the frictional coefficient μ on the surface of a photoreceptor 5 and with a controlling means which controls the cleaning conditions for the photoreceptor 5 according to the frictional coefficient μ detected by the detecting means. Further, the detecting means detects the frictional coefficient μ by measuring a driving torque of the photoreceptor 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image by an electrostatic copying process, such as a copying machine, a facsimile machine, and a printer, and also relates to a toner used by the image forming apparatus.

An image forming apparatus using an electrophotographic process includes a photosensitive member as a latent image carrier, charges the surface of the photosensitive member by discharging, charges the surface of the photosensitive member to form an electrostatic latent image, The electrostatic latent image is supplied with toner to be visualized, and the formed visible image on the surface of the photoreceptor is transferred onto the transfer paper surface, and then fixed and discharged.
In recent years, there has been an increasing demand for higher image quality, and in order to realize particularly high-definition color image formation, toner particles are being made smaller and spherical. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner is being adopted.

However, when a toner having a spherical shape and a reduced particle size is used, there are some problems in cleaning on the photoreceptor after image formation.
One of them is that it is difficult to clean the toner remaining untransferred on the photosensitive member by a blade cleaning method that is generally used. The cleaning blade removes toner while rubbing the surface of the photoconductor, but the edge portion of the cleaning blade is deformed due to frictional resistance with the photoconductor, so that a minute space is generated between the photoconductor and the cleaning blade. The smaller the toner particle size, the easier it is to enter this space. Since the rolling friction force is smaller as the invading toner has a shape close to a spherical shape, it starts to roll in the space between the photosensitive member and the cleaning blade, passes through the cleaning blade, and leads to poor cleaning.
With respect to such a problem, a method for deforming a small particle size toner has been proposed. For example, the polymer after suspension polymerization is heated above the glass transition point in a dispersion medium to obtain aggregated particles. The aggregated particles are introduced into a heated jet stream, and the aggregated particles are crushed and simultaneously dried. Thus, a method for obtaining an irregularly shaped small particle size toner (see, for example, Patent Document 1), a binder resin and a colorant are mixed in a solvent immiscible with water, and in an aqueous medium in the presence of a dispersion stabilizer. And a solvent is removed from the resulting suspension by heating and / or decompression to obtain toner particles having irregularities on the surface (for example, see Patent Document 2).

  One of the countermeasures against defective cleaning is a means for continuously detecting the wear of the cleaning blade, and the pressure contact angle of the cleaning blade to the photoconductor according to the amount of wear of the cleaning blade detected by the detecting means. There has been disclosed a cleaning device provided with means for automatically adjusting the frictional force between the blade and the photoconductor in a direction to increase the frictional force (for example, Patent Document 3). However, it is difficult to accurately measure the amount of wear of the cleaning blade. Further, it is difficult to prevent blade peeling even if only the state of the cleaning blade is grasped and the contact condition is adjusted.

Japanese Patent Laid-Open No. 5-188642 JP 9-15903 A JP 7-36339 A

  Accordingly, the present invention has been made in view of the above problems, and the problem is that the amount of toner passing through the photoconductor is small by detecting the relationship between the cleaning device and the photoconductor and controlling the cleaning conditions. An image forming apparatus is provided. Another object is to provide an image forming apparatus in which the cleaning blade is not turned up during cleaning.

The features of the present invention, which is a means for solving the above problems, are listed below.
1. An image forming apparatus according to the present invention includes an image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, and the surface of the charged image carrier is exposed based on image data to form a latent image. An exposure device for writing, a developing device for supplying toner to the latent image formed on the surface of the image carrier to make it visible, and a recording medium after transferring the visible image on the surface of the image carrier directly or to an intermediate transfer member In an image forming apparatus comprising a transfer device for transferring a toner image, a cleaning device for cleaning an image carrier or an intermediate transfer member, and a fixing device for fixing a toner image on a recording medium, the surface of the image carrier or intermediate transfer member It is characterized by comprising a detecting means for detecting a friction coefficient, and an adjusting means for adjusting the cleaning condition of the image carrier or the intermediate transfer body according to the friction coefficient detected by the detecting means.
2. Further, the image forming apparatus of the present invention is characterized in that the detecting means detects a friction coefficient by measuring a driving torque of the image carrier or the intermediate transfer member.
3. In the image forming apparatus of the present invention, the detecting unit further detects a friction coefficient by measuring a current of a motor that drives the image bearing member or the intermediate transfer member.
4). The image forming apparatus of the present invention is further characterized in that the cleaning device includes a cleaning blade.
5). The image forming apparatus of the present invention is further characterized in that the cleaning device adjusts the contact pressure of the cleaning blade.
6). The image forming apparatus of the present invention is further characterized in that the cleaning device adjusts the contact angle of the cleaning blade.
7). The image forming apparatus of the present invention is further characterized in that the cleaning device adjusts a contact amount of the cleaning blade.
8). The image forming apparatus of the present invention is further characterized in that the coefficient of friction of the image carrier is 0.1 or more.
9. Further, in the image forming apparatus of the present invention, the cleaning device further sets the contact pressure Y of the cleaning blade to 0.1 N / cm or more when the friction coefficient μ of the image carrier is less than 0.1.
When the friction coefficient μ of the image carrier is 0.1 or more, Y (N / cm) ≧ k × μ (k: 1 as a proportional coefficient)
It adjusts so that the relationship of may be satisfied.

10. In the image forming apparatus of the present invention, the volume average particle diameter is 10 μm or less, and the ratio (dispersity) of the volume average particle diameter to the number average particle diameter is in the range of 1.00 to 1.40. It is characterized by using toner.
11. The image forming apparatus of the present invention is further characterized in that the image forming apparatus uses a toner having an average circularity in a range of 0.93 to 1.00.
12 In addition, the image forming apparatus of the present invention further has a substantially spherical appearance, and has a ratio between the major axis and the minor axis (r2 / r1) in the range of 0.5 to 1.0, and the thickness and the shortness. A toner having a ratio (r3 / r2) to an axis in a range of 0.7 to 1.0 and satisfying a relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 is used.
13. The image forming apparatus of the present invention further comprises a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of resin fine particles. It is characterized by using a toner that undergoes crosslinking and / or elongation reaction.
14 Further, the image forming apparatus of the present invention is characterized in that the charging device further includes a roller-shaped charging member that is not in contact with the image carrier.
15. The image forming apparatus according to the present invention further includes a process cartridge that integrally supports at least the image carrier and the cleaning device and is detachable from the image forming apparatus main body.

16. The toner of the present invention includes an image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, and exposure that writes the latent image by exposing the charged image carrier surface based on image data. The image forming apparatus, a developing device that supplies toner to the latent image formed on the surface of the image carrier and visualizes it, and the visible image on the surface of the image carrier is transferred directly or to an intermediate transfer body and then transferred to a recording medium. A transfer device, a cleaning device for cleaning the image carrier or the intermediate transfer member, and a fixing device for fixing the toner image on the recording medium, and the image forming device includes an image carrier or an intermediate transfer member. In a toner used for an image forming apparatus, comprising: a detecting unit that detects a friction coefficient of a surface; and an adjusting unit that adjusts a cleaning condition of the image carrier or the intermediate transfer member based on the friction coefficient detected by the detecting unit. In 10μm or less, the ratio of the volume average particle diameter to the number average particle diameter (dispersity), characterized in that using the toner in the range of from 1.00 1.40.
17. The toner of the present invention is further characterized in that the average circularity is in the range of 0.93 to 1.00.
18. The toner of the present invention has a substantially spherical appearance, and the ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3). / R2) is in the range of 0.7 to 1.0, and satisfies the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3.
19. In the toner of the present invention, the image forming apparatus further includes a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium. The crosslinking and / or extension reaction is carried out in the presence of.

According to the present invention, the image forming apparatus according to the present invention captures the surface state of the photoconductor, in particular, the state of the friction coefficient, and changes the cleaning condition according to the state for a long period of time. A stable cleaning blade type cleaning can be performed. This also prevents toner contamination of the charging roller, and a high quality image can be obtained.
Moreover, even if the cleaning property is low with a spherical toner which is one of the toners of the present invention, it can be cleaned over a long period of time.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 1 is an overall configuration diagram showing an example in which the present invention is applied to a full-color small printer. In an image forming apparatus main body (hereinafter, simply referred to as “apparatus main body”) 1, image forming units 2A, 2B, 2C, and 2D having four photosensitive members as image carriers are connected to the apparatus main body 1. Are detachably attached. A transfer device 3 in which a transfer belt 31 is rotatably mounted in a direction indicated by an arrow A between a plurality of rollers is disposed in the approximate center of the device body 1.
The photosensitive member 5 provided in each of the image forming units 2A, 2B, 2C, and 2D is disposed so as to contact the upper surface of the transfer belt 31. In correspondence with the image forming units 2A, 2B, 2C, and 2D, developing devices 10A, 10B, 10C, and 10D having different toner colors are arranged.
The image forming units 2A, 2B, 2C, and 2D are units having the same configuration, the image forming unit 2A forms an image corresponding to magenta, and the image forming unit 2B forms an image corresponding to cyan. The image forming unit 2C forms an image corresponding to the yellow color, and the image forming unit 2D forms an image corresponding to the black color.

The writing unit 6 is disposed above the image forming units 2A, 2B, 2C, and 2D, and the duplex unit 7 is disposed below the transfer belt 31. This small printer is equipped with a reversing unit 8 on the left side of the apparatus main body 1 for reversing and ejecting the transfer paper after image formation or transporting it to the duplex unit 7.
The writing unit 6 is arranged in four laser diode (LD) light sources prepared for each color, a set of polygon scanners composed of six polygon mirrors and a polygon motor, and the route of each light source. It is composed of a lens such as an fθ lens or a long cylindrical lens, or a mirror. Laser light emitted from the laser diode is deflected and scanned by a polygon scanner and irradiated onto the photosensitive member 5.
The duplex unit 7 includes a pair of conveyance guide plates 45a and 45b and a pair of (four sets in this example) conveyance rollers 46. In the double-sided image formation mode in which an image is formed on both sides of a transfer sheet, The transfer sheet having an image formed on one side, conveyed to the reversal conveyance path 54 of the reversing unit 8 and switched back is received and conveyed toward the paper feeding unit.

The reversing unit 8 includes a plurality of paired transport rollers 46 and a plurality of paired transport guide plates 45. As described above, the reversing unit 8 reverses the transfer paper when forming a double-sided image to the double-sided unit 7. It carries out functions such as unloading, discharging the image-formed transfer paper out of the machine in the same orientation, or inverting the front and back and discharging it out of the machine. Separating sheet feeding units 55 and 56 for separating and feeding the transfer sheets one by one are provided in the sheet feeding unit in which the sheet feeding cassettes 11 and 12 are provided.
Between the transfer belt 31 and the reversing unit 8, there is provided a fixing device 9 for fixing the image of the transfer paper onto which the image has been transferred. A reverse discharge path 20 is formed on the downstream side of the fixing device 9 in the transfer sheet conveyance direction, and the transfer sheet conveyed there can be discharged onto a discharge tray 26 by a discharge roller pair 25. .
In addition, in the lower part of the apparatus main body 1, paper feeding cassettes 11 and 12 that can store transfer papers of different sizes in two upper and lower stages are arranged. Further, a manual feed tray 13 is provided on the right side surface of the apparatus main body 1 so as to be openable and closable in the direction indicated by the arrow B, and the manual feed tray 13 is opened so that manual feeding can be performed therefrom.

  Next, the operation of the image forming apparatus in image formation will be described. When the image forming operation is started, each photoconductor rotates in the clockwise direction in FIG. Then, the surface of each photoconductor 5 is uniformly charged by the charging roller 141. Then, laser light corresponding to a magenta image is written to the photoconductor 5 of the image forming unit 2 by the writing unit 6, and laser light corresponding to a cyan image is applied to the photoconductor 5 of the image forming unit 2B. The 2C photoconductor 5 is irradiated with a laser beam corresponding to a yellow image, and the photoconductor 5 of the image forming unit 2D is irradiated with a laser beam corresponding to a black image, and a latent image corresponding to the image data of each color. Are formed respectively. Each latent image reaches the position of the developing devices 10A, 10B, 10C, and 10D by the rotation of the photosensitive member 5, and is developed there by toners of magenta, cyan, yellow, and black. Become.

On the other hand, the transfer paper is fed from the paper feed cassettes 11 and 12 by the separation paper feed unit, and the toner formed on each photoconductor 5 by the registration roller pair 59 provided immediately before the transfer belt 31. It is conveyed at the same timing as the image. The transfer paper is charged with a positive polarity by a paper suction roller 58 disposed near the entrance of the transfer belt 31, and is thereby electrostatically attracted to the surface of the transfer belt 31. The transfer paper is conveyed while being adsorbed to the transfer belt 31, and magenta, cyan, yellow, and black toner images are sequentially transferred to form a four-color superimposed full-color toner image. . The transfer paper is heated and pressed by the fixing device 9 to melt and fix the toner image, and then passes through a paper discharge system corresponding to the designated mode to the paper discharge tray 26 at the top of the apparatus main body 1. When the paper is reversed, discharged straight from the fixing device 9 and straightly discharged through the reversing unit 8, or when the double-sided image forming mode is selected, the reversing conveyance path in the reversing unit 8 is set. After being fed in, it is switched back and transported to the duplex unit 7, and is fed again from there, and after the image is formed on the back surface in the image forming unit provided with the image forming units 2 A, 2 B, 2 C, and 2 D Discharged.
On the other hand, the photosensitive member 5 separated from the transfer belt 31 continues to rotate as it is, and the brush roller 161 applies the lubricant scraped off from the molded lubricant 162 to the photosensitive member 5.
In the subsequent image formation, the above-described image forming process is repeated. However, the lubricant film formed on the photoconductor 5 is very thin, so that charging by the charging device 14 is not hindered. Thereafter, the toner image developed again on the photosensitive member 5 is transferred to the transfer paper adsorbed on the transfer belt 31.

The developing devices 10A, 10B, 10C, and 10D include a developing roller that faces the photoreceptor 5, a screw that conveys and stirs the developer, a toner concentration sensor, and the like. The developing roller is composed of an outer rotatable sleeve and an inner magnet. In accordance with the output of the toner density sensor, toner is supplied from the toner supply device. In this embodiment, a two-component developer composed of toner and carrier is used as the developer.
The carrier is generally composed of the core material itself, or a carrier provided with a coating layer on the core material. The core material of the resin-coated carrier that can be used in the present invention is ferrite or magnetite. The particle size of the core substance is 20 to 65 μm, preferably about 30 to 60 μm. As the resin used for forming the carrier coating layer, a styrene resin, an acrylic resin, a fluororesin, a silicone resin, a mixture thereof, or a copolymer can be used. As a method for forming the coating layer, a resin may be applied to the surface of the carrier core material particles by a spraying method, a dipping method, or the like, as in the conventional case.

FIG. 2 is a schematic diagram showing the configuration of the image forming unit. As shown in FIG. 2, the image forming units 2A, 2B, 2C, and 2D include a photoreceptor 5 on which an electrostatic latent image is formed, a charging device 14 that charges the surface of the photoreceptor 5, and the photoreceptor 5 And a cleaning device 15 for cleaning the surface of the substrate.
The charging roller 141 in the charging device 14 is conductive or semiconductive, and applies a DC and / or AC voltage to apply a charge on the photoconductor 5 to charge the photoconductor 5. A charging roller cleaning brush 142 for cleaning the roller surface is in contact with the charging roller 141.
The cleaning device 15 includes a cleaning blade 151 that cleans untransferred toner on the surface of the photoconductor 5, a support 154 that supports the cleaning blade 151, a blade pressure spring 152 that adjusts the contact pressure of the cleaning blade 151, and the cleaning blade 151. A rotation fulcrum 153 that is rotated by the contact pressure is provided.
The lubricant application device 16 includes a brush-like roller 161 for applying the lubricant, a lubricant molded body 162 in which the lubricant is molded into a box shape, a brush-like roller scraper 158 for separating the toner adhering to the brush-like roller, A bar pressurizing spring 163 for adjusting the pressure pressed against the brush-like roller of the lubricant molding 162 is provided.
In addition to the photosensitive member 5 and the transfer conveyance belt 31, the image forming apparatus of the present invention detects the friction coefficient of the surface of the rotating member such as the intermediate transfer member and the charging roller 14, and the detection unit. Adjusting means for adjusting the cleaning condition of the photoconductor 5 or the like according to the friction coefficient. These will be described later.

FIG. 3 is a schematic view showing the contact condition of the cleaning blade. The contact method of the cleaning blade 151 may be either a counter method or a trailing method. In particular, a counter system is preferable. Even if the contact pressure with respect to the photoconductor 5 is small, the cleaning property is high and the photoconductor 5 is less worn.
The cleaning blade 151 preferably has a hardness (JIS-A) in the range of 65 to 85 °. If the hardness is less than 65, the cleaning blade 151 is greatly deformed and it becomes difficult to clean the toner or the like. If the hardness exceeds 85, the photoconductor 5 is abraded and the life of the image forming apparatus is shortened. In addition, the cleaning blade 151 in the cleaning device of the present invention is preferably fixed or integrally formed with the support plate 154 in order to maintain a uniform contact angle and contact pressure.

  Further, the contact pressure of the cleaning blade 151 when the cleaning device is provided is preferably 0.1 N / cm or more. Furthermore, 0.6 N / cm or less is preferable. If the contact pressure is less than 0.1 N / cm, it is difficult to clean the toner less than 2 μm. If the contact pressure exceeds 0.6 N / cm, the tip of the cleaning blade 151 is likely to be turned or bound, resulting in poor cleaning such as chatter. It becomes easy and the cleaning property decreases.

Of the contact conditions of the cleaning blade 151, the nip width may be adjusted according to conditions relating to the material such as the free length, thickness, and elastic modulus of the cleaning blade 151.
For example, the elastic modulus is 4.5 MPa to 10 MPa, the free length of the cleaning blade 151 is 5 mm to 12 mm, the thickness of the cleaning blade 151 is 1 mm to 2 mm, the contact angle is 5 ° to 25 °, and the biting amount is 0.1 mm or more and 2.0 mm or less is preferable. The contact angle of the cleaning blade 151 is preferably in the range of 5 ° to 25 ° from the tangent of the contact position. If the contact angle is less than 5 °, cleaning failure due to toner passing through tends to occur, and if it exceeds 25 °, the blade may be turned up during cleaning. The amount of biting of the cleaning blade 151 into the photoreceptor 5 is preferably in the range of 0.1 mm to 2.0 mm. If the thickness is less than 0.1 mm, the contact area between the cleaning blade 151 and the photosensitive member 5 is small, resulting in poor cleaning through which the toner slips. If the thickness exceeds 2.0 mm, the frictional force with the photosensitive member 5 is increased and the blade is turned or bounded. It becomes easy. In addition, cleaning defects such as squeal and chatter due to blade vibration occur.

  Further, the cleaning device 15 contacts the lubricant molded body 162 to scrape off the lubricant and supply the brush-like roller 161 to be supplied to the surface of the photosensitive member 5, and the brush-like roller for removing the toner attached to the brush-like roller 161. A scraper 158 and a pressure spring 163 that presses the lubricant molded body 162 against the brush roller 161 with a predetermined pressure are provided. Examples of the lubricant of the lubricant molded body 162 include lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate, and linolene. Fatty acid metal salts such as zinc acid, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-oxafluoropropylene Fluorine-based resins such as copolymers are listed. In particular, a metal stearate having a large effect of reducing the friction of the photoreceptor 5 and further zinc stearate are more preferable. As the molded lubricant 162, a product obtained by melting and solidifying a fatty acid metal salt such as zinc stearate into a rod shape can be used. The brush-like roller 161 has a shape extending in the axial direction of the photoreceptor 5. The pressure spring 163 is urged against the brush-like roller 161 so that almost all of the lubricant molding 162 can be used up. Since the lubricant molded body 162 is a consumable product, its thickness decreases with time, but since it is pressurized by the pressure spring 163, the lubricant is scraped off by always contacting the brush-shaped roller 161, Thereafter, the photosensitive member 5 is supplied and applied. These lubricants are fixed and brought into contact with the brush-like roller 161. When adjusting the lubricant application amount, the application amount to the photoconductor 5 can be adjusted by a pressure spring 163 which is a spring material.

  At this time, the brush-like roller 161 is disposed so as to rub against the cleaning blade 151. As a result, the cleaning blade 151 cleans, and the toner collected at the tip of the cleaning blade 151 is scraped off by the brush-like roller 161 that applies the lubricant, and is moved to the toner conveying auger 155 side by the brush-like roller 161 to be brush-like. The waste scraper 158 is ejected from the brush and separated, and the waste toner collected by rotating the toner transport auger 155 is transported to a waste toner storage unit (not shown). To the cleaning device 15, the toner cleaned by the cleaning blade 151 was transported by a brush or film that transports the cleaning device 15 into the cleaning device 15. The mechanism can be arranged in the cleaning device 15 and the structure can be simplified.

The brush-shaped roller 161 can use fibers selected from polyamide resins such as styrene resin, acrylic resin, polyester resin, fluorine resin, and nylon. In particular, a polyamide resin and a polyester resin that are resistant to wear are good, and it is preferable that the conductive powder is not contained and that the insulating property be maintained. Specifically, the electric resistance is set to 10 ¹² Ωcm or more. In the case of conductivity, the charged toner is attracted to the brush with a mirror image force, so that it is difficult to separate even with the brush-shaped roller scraper 158. By making the brush insulative, the toner from the cleaning blade 151 can be easily scraped off and separated by the brush-shaped roller scraper 158, so that the cleaning toner can be quickly collected. Stable cleaning is possible. In addition, the toner scraped off by the brush-like roller 161 finely scrapes off the lubricant from the lubricant molded body 162 and applies the lubricant to the cleaning blade 151 or the photoreceptor 5. By uniformly applying the lubricant, it is possible to suppress the occurrence of poor cleaning and to prevent background stains.

Here, the lubricant molded body 162 is pressed against the brush-like roller 161 by a pressure spring 163 including its own weight with a pressure of 200 mN or more. As the pressure increases, the amount of lubricant that the brush roller 161 scrapes off from the molded lubricant 162 increases, and the amount of lubricant applied to the photoreceptor 5 increases, reducing the coefficient of friction of the photoreceptor 5. be able to.
Further, the brush-like roller 161 is rotated in the same direction at a portion in contact with the photoreceptor 5. By rotating in this direction, the lubricant adhering to the brush-like roller 161 can be supplied without giving an impact to the photoreceptor 5. It is not necessary to form a lubricant film when the brush roller 161 supplies the photosensitive member 5, and the lubricant supplied on the photosensitive member 5 forms a lubricant film by the pressing force of the cleaning blade 151. To do. Therefore, it is preferable here to rotate in the same direction in order to supply without impact. Furthermore, the peripheral speed ratio between the brush roller 161 and the photosensitive member 5 (photosensitive member peripheral speed / brush roller peripheral speed) is preferably in the range of 0.8 to 1.2. When the peripheral speed ratio is less than 0.8, the supply amount of the lubricant decreases, and when it exceeds 1.2, the photoreceptor 5 may be damaged by impact, and the life of the photoreceptor 5 may be shortened. Further, in order to supply the lubricant from the brush to the photoconductor 5 with a small impact, it is further preferable that the ratio is in the range of 1.0 to 1.1.

  By supplying this lubricant to the surface of the photoreceptor 5, a lubricant film is formed on the surface of the photoreceptor 5, and the friction coefficient is set to 0.1 or more. Further, the coefficient of friction of the photosensitive member 5 is preferably 0.4 or less, and more preferably 0.2 or less. When the friction coefficient is 0.4 or less, the interaction between the photoconductor 5 and the toner is reduced, and the toner on the photoconductor 5 can be easily separated to increase the transfer rate. Further, an increase in friction between the cleaning blade 151 and the photosensitive member 5 can be suppressed, and the cleaning efficiency can be improved. In particular, in the case of toner having a high degree of circularity, the toner easily rolls on the photoconductor 5, so that the occurrence of poor cleaning can be suppressed. Further, the occurrence of cleaning failure due to long-term use can be suppressed by increasing the transfer rate and reducing the amount of toner to be cleaned. Furthermore, 0.2 or less is more preferable. On the other hand, if the friction coefficient is less than 0.1, a cleaning failure occurs that slips too much between the cleaning blade 151 and slips through the toner cleaning blade 151 on the photosensitive member 5.

  Here, the friction coefficient of the photosensitive member 5 was measured by the Euler belt method as follows. In this case, medium-quality high-quality paper as a belt is stretched around the drum circumference ¼ so that the paper scraper is in the longitudinal direction, and a load of, for example, 0.98 N (100 gr) is applied to one of the belts. The force gauge is installed on the other side, the force gauge is pulled, and the load at the time when the belt moves is read, and the friction coefficient μs = 2 / π × 1n (F / 0.98) (where μ is the static friction coefficient, F: Measurement value) Note that the coefficient of friction of the photoconductor 5 in the image forming apparatus 1 is a value when a steady state is obtained by image formation. This is because the coefficient of friction of the photosensitive member 5 is affected by the other apparatus provided in the image forming apparatus 1 and therefore changes from the value of the coefficient of friction immediately after the image formation. However, the value of the friction coefficient becomes a substantially constant value by forming about 1,000 images on A4 size recording paper. Therefore, the coefficient of friction referred to here means the coefficient of friction when it becomes constant in the steady state.

Further, as described above, the image forming apparatus of the present invention includes a detecting unit that detects the friction coefficient of the surface of the rotating body such as the intermediate transfer body and the charging roller 14 in addition to the photosensitive body 5 and the transfer conveyance belt 31. Adjusting means for adjusting the cleaning condition of the photoconductor 5 and the like according to the friction coefficient detected by the detecting means.
This image forming apparatus is provided with a detection means (not shown) for detecting the friction coefficient of the surface of the photoreceptor 5 or the transfer belt 31. The surface friction on the photoconductor 5 or the like is not constant, and varies depending on the image forming mode such as environmental conditions such as temperature and humidity, the amount of toner actually developed, and the presence or absence of a gray image. When the presence state of the toner changes, the toner pressed against the photoconductor 5 and the like by the toner and the cleaning blade scrapes off the lubricant on the surface of the photoconductor 5 and the like, so that the friction coefficient changes. In addition to this, the lubricant on the photoconductor 5 can be scraped off by rubbing the photoconductor 5 while the magnetic brush on the developing sleeve of the developing device 10 rotates. Further, the lubricant on the photosensitive member 5 is scraped off by contacting the recording member or the transfer belt of the transfer device 3 while being pressed. Therefore, by providing a detection means, the friction coefficient of the photosensitive member 5 or the like at that time is detected.

This detection means can be detected by measuring the drive torque on the drive shaft that drives the photosensitive member 5 and the transfer belt 31 to rotate. This detection means drives the motor from the motor control unit that drives the photoconductor 5, rotates the photoconductor 5, and directly measures the rotational torque of the photoconductor 5 during this drive. The photoreceptor conditions such as the weight and diameter of the photoreceptor 5, the load when the developer on the developing sleeve of the developing device 10 is brought into contact with the photoreceptor 5, the load when the transfer belt 31 is brought into contact, and the like are input in advance. A table is prepared, and then the difference between the initial driving torque when the cleaning blade 151 is brought into contact with the driving torque during use is detected. Further, a table showing the relationship between the difference in driving torque and the friction coefficient μ between the photosensitive member 5 is prepared, and the friction coefficient of the photosensitive member μ is derived therefrom. Alternatively, the photosensitive member 5 may be stopped after a predetermined image forming operation is performed in advance, the motor is rotated at a set torque, the driving torque at this time is measured, and the friction characteristic of the photosensitive member 5 may be measured.
Further, as this detecting means, the current value when the motor is rotated is detected, and the load current applied to the motor when the photosensitive member 5 or the transfer belt is rotated at a constant speed and when the motor is in use. Measure the difference. In this case, a table showing the relationship between the difference in load current of the motor and the friction coefficient of the photosensitive member 5 or the like is created in advance. The friction coefficient of the photoconductor 5 and the like can be detected from the difference in current.
Further, it may be detected by an encoder provided on the drive shaft of the photosensitive member 5. The encoder detects the rotational speed of the drive shaft as a light ON / OFF signal by sandwiching the light emitting element and the light receiving element in a slit disk having a grid-shaped hole attached on the drive shaft. . At this time, the rotational speed and the rotational amount of the photosensitive member 5 are detected, and the friction coefficient μ is detected based on the given data from a previously created table showing the relationship between these and the friction coefficient of the photosensitive member 5. be able to.

Further, the contact condition of the cleaning blade 151 is adjusted using an adjusting means for adjusting the cleaning condition according to the detected friction coefficient.
A line sensor or the like that can detect the displacement of the cleaning blade 151 is provided on the cleaning blade 151 or its support plate 154, and the contact angle of the cleaning blade 151 can be detected by a signal from the sensor. The contact condition of the cleaning blade 151 is controlled according to the detected angle. In order to control the contact angle, shafts are provided at both ends of the support plate 154 that supports the cleaning blade 151, and these shafts are supported by bearings provided in the cleaning device casing, and a gear is provided on the shaft. The stepping motor having a gear meshed with the gear can be rotated and adjusted by a control signal from the main body of the image forming apparatus 1. Further, this cleaning device may include a solenoid, and by operating the solenoid, the support plate 154 may be rotated via the arm to control the contact angle of the cleaning blade 151 with respect to the photosensitive member. Further, the solenoid may be controlled by rotating a cam. Similarly, the contact amount can be controlled by moving the support plate 154 that supports the cleaning blade 151.

The coefficient of friction μ of the photosensitive member 5 is 0.1 or more, and more preferably 0.4 or less. As described above, this greatly affects the cleaning performance of the toner. Further, when the coefficient of friction of the photosensitive member 5 is less than 0.1, abnormalities such as turning of the cleaning blade 151 or generation of chatter noise are reduced, but the amount of the lubricant passing through the cleaning blade 151 is increased. When the slipping amount of the lubricant increases, problems such as adhering to the carrier on the charging roller 141 and the developing sleeve of the developing device 10 and soiling the developing device 10 occur.
Therefore, in the image forming apparatus 1 of the present invention, when the coefficient of friction of the photosensitive member 5 becomes less than 0.1, this is detected by the detecting means, and the contact angle of the cleaning blade 151 is increased by the adjusting means, and the cleaning is performed. The occurrence of an abnormality in the blade 151 is prevented. On the other hand, when the friction coefficient μ of the photosensitive member 5 exceeds 0.4, the amount of toner slipping from the cleaning blade decreases, and an abnormal image with white spots is difficult to form. However, the stress applied to the tip of the cleaning blade increases, and abnormalities such as turning over of the cleaning blade 151 or generation of chatter noise may occur. In this case, the occurrence of abnormality can be prevented by reducing the contact angle of the cleaning blade 151 with the adjusting means.

Further, the contact pressure Y of the cleaning blade 151 satisfies the relationship of contact pressure Y (N / cm) ≧ k × μ (k: 1 by a proportional coefficient) with respect to the friction coefficient μ of the photosensitive member 5. As described above, when the friction coefficient μ is decreased, the adhesion force of the toner to the photosensitive member is reduced, the cleaning property is improved, and the cleaning becomes easy. Therefore, the toner can be cleaned even if the contact pressure, which is a major factor in the cleaning performance of the cleaning blade 151, is small. On the other hand, the friction coefficient μ is increased, the adhesion force of the toner to the photoreceptor is increased, the cleaning property is lowered, and a large contact pressure is required for cleaning the toner. Thus, the contact pressure Y and the friction coefficient μ are in a proportional relationship, and the relationship of the proportional coefficient k is established in a practical image forming apparatus. Furthermore, by making the contact pressure Y larger than the friction coefficient μ, it is possible to greatly suppress the turning of the cleaning blade 151 or the occurrence of chatter noise.
At this time, if the contact pressure Y is increased from the beginning, mechanical damage to the photoconductor 5 increases, wear of the surface of the photoconductor 5 increases, and partial unevenness is formed on the surface of the photoconductor 5. For this reason, the contact with the cleaning blade 151 becomes non-uniform, and a cleaning failure may occur from a portion where the contact pressure is low.
On the other hand, the friction coefficient μ of the photoconductor 5 becomes large due to adhesion of a discharge product and a toner component to the photoconductor 5 due to long-term use. As much as possible by applying a lubricant, the friction coefficient μ of the surface of the photosensitive member 5 is lowered and the contact pressure Y is lowered. However, when the friction coefficient μ on the surface of the photosensitive member 5 is increased, it is preferable to increase the contact pressure Y in order to prevent the occurrence of defective cleaning.

Here, the toner may be a pulverization system or a polymerization system as long as it is a toner containing at least a binder resin and a colorant. In the pulverizing toner, the binder resin, the colorant, the release agent, and the like were melted and mixed with heat and pressure, cooled, and then pulverized. In the pulverization, the impact plate is made to collide with the pressure of air or the toners are made to collide with each other. In addition, the polymerization toner forms particles in a solvent in which a binder resin, a colorant, a release agent, and the like are added, causes the monomer to undergo a polymerization reaction, and then is dried to form a toner.
However, it is suitable for practical use of a toner having a small particle size and a spherical shape, which deteriorates the cleaning property. The volume average particle diameter (Dv) of the toner is preferably 10 μm or less, particularly preferably 3 to 8 μm. It is said that the smaller the toner particle size, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning property. Further, when the volume average particle size is smaller than the above range, in the two-component developer, the toner is fused to the surface of the magnetic carrier in the developing device for a long period of time, and the charging ability of the magnetic carrier is lowered. When used as a developer, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur. On the contrary, when the volume average particle size of the toner is larger than the above range, it becomes difficult to obtain a high-resolution and high-quality image, and the balance of the toner in the developer is performed. In many cases, the variation in the particle size of the toner becomes large. Therefore, by setting the thickness to 10 μm or less, a high-quality image can be obtained. In particular, when used in a full color image forming apparatus, an excellent resolution of the image can be obtained.
Further, 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. When the ratio (Dv / Dn) exceeds 1.40, the charge amount distribution becomes wide and the resolving power decreases, which is not preferable.
The average particle size and particle size distribution of the toner can be measured using a Coulter Counter TA-II and a Coulter Multisizer II (both manufactured by Coulter). In the present invention, a counter-counter type TA-II is used, connected to an interface (manufactured by Nikka Giken) and PC9801 personal computer (manufactured by NEC) that outputs number distribution and volume distribution, and measurement is performed. did.

  Further, the image forming apparatus of the present invention is suitable for toner having an average circularity φ of the toner in the range of 0.93 to 1.00. By increasing the lightness of the circle, high image quality can be obtained because dot reproducibility is good, resolution is excellent, and transferability is also good. When the average circularity φ is less than 0.93 and the toner is separated from the spherical shape, it is difficult to obtain a high-quality image with sufficient transferability or dust. The circularity of the toner is a value obtained by optically detecting particles and dividing by the perimeter of an equivalent circle having the same projected area. Specifically, the measurement is performed using a flow type particle image analyzer (FPIA-2000; manufactured by Sysmex Corporation). In a predetermined container, 100 to 150 mL of water from which impure solids are removed in advance is added, 0.1 to 0.5 mL of a surfactant is added as a dispersant, and about 0.1 to 9.5 g of a measurement sample is further added. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and distribution of the toner are measured at a dispersion concentration of 3,000 to 10,000 pieces / μL.

The toner preferably 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.
FIG. 4 is a diagram schematically showing the shape of the toner for explaining 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 shape factor SF-1 of the toner is close to 100, the shape of the toner is close to a sphere, and the contact between the toner and the toner or the contact between the toner and the photosensitive member becomes a point contact. -Adhesive force between each other becomes weak, and hence the fluidity becomes high. Also, the adhesive force between the toner and the photosensitive member becomes weak, and the transfer rate becomes high. On the other hand, if the value of the shape factor SF-1 is greater than 180, the shape factor SF-1 becomes indefinite, which is not preferable because developability and transferability deteriorate.

The shape factor SF-2 indicates the ratio of the uneven shape of the toner, and is represented by the following formula (2). This is 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)
The closer the value of SF-2 is to 100, the smoother the unevenness of the toner surface. In order to improve the cleaning property, it is preferable that the surface has moderate unevenness. However, when the shape factor SF-2 is larger than 180, the unevenness becomes conspicuous so that the toner is scattered on the image. This is not preferable because the image quality is lowered.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.) and introducing it into an image analyzer (LUSEX 3: manufactured by Nireco). Analyzed and calculated.

The image forming apparatus of the present invention uses a non-contact charging roller as a charging member for charging the photosensitive member. The charging roller 141 includes a conductive substrate and a surrounding resistance layer. The conductive substrate is a cylindrical member of a stainless steel (hereinafter also referred to as SUS) having a diameter of 8 to 20 mm. The conductive substrate may be lightened by using aluminum. The resistance layer is made of a polymer material obtained by kneading a conductive material into ABS resin or the like, and a fluorine-based resin is formed as a thin layer on the surface. Examples of the conductive material include a metal ion complex and carbon black.
The charging roller 141 is provided with spacers at both ends in the longitudinal direction, and these charged spacers are brought into contact with non-image forming regions at both ends of the photoconductor 5 to thereby provide a surface to be charged and a surface of the charging roller 141 on the surface of the photoconductor. The space between the charging surface and the charging surface is maintained so that the distance at the closest portion is 5 to 100 μm. This closest distance is more preferably set to 30 to 65 μm. By making the contactless, it is possible to prevent the toner slipped from the cleaning blade 151 from adhering to the charging roller 141. The charging roller is the first stage of image formation. Here, when toner adheres to the charging roller 141, the photosensitive member 5 becomes non-uniformly charged and a high-quality image cannot be obtained.

The toner used in the image forming apparatus of the present invention is 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. Obtained by crosslinking and / or elongation reaction in an aqueous solvent. Below, the constituent material and manufacturing method of a toner are demonstrated.
Here, the constituent material and production example of the toner by the wet polymerization method will be described, but the toner of the present invention may be a dry melt kneading method.

(Modified polyester)
There are bonding groups other than ester groups and functional groups contained in acid and alcohol monomer units in the polyester resin, and resin components with different configurations are bonded in the polyester resin through covalent bonds, ionic bonds, etc. Indicates a state.
For example, the polyester terminal is reacted with something other than an ester bond. Specifically, a functional group such as an isocyanate group that reacts with an acid group or a hydroxyl group is introduced into the terminal and further reacted with an active hydrogen compound to modify or extend the terminal.
Further, compounds having a plurality of active hydrogen groups include those in which polyester ends are bonded to each other (urea-modified polyester, urethane-modified polyester, etc.).
In addition, a reactive group such as a double bond is introduced into the polyester main chain, radical polymerization is caused therefrom, and a carbon-carbon bond graft component is introduced into the side chain or the double bonds are bridged. Included (styrene modified, acrylic modified polyester, etc.)
In addition, a resin component having a different structure is copolymerized in the polyester main chain or reacted with a terminal carboxyl group or hydroxyl group. For example, those having a terminal copolymerized with a silicone resin modified with a carboxyl group, a hydroxyl group, an epoxy group, or a mercapto group are included (silicone-modified polyester and the like).

(Synthesis example of modified polyester)
Examples of the urea-modified polyester (i) include a reaction product of a polyester prepolymer (A) having an isocyanate group and an amine (B). As the polyester prepolymer (A) having an isocyanate group, a polycondensate of a polyol (1) and a polycarboxylic acid (2) and a polyester having an active hydrogen group are further added to the polyisocyanate (3). Examples include reacted products. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (an alcoholic hydroxyl group and a phenolic hydroxyl group), an amino group, a carboxyl group, and a mercapto group. Among these, an alcoholic hydroxyl group is preferable. is there.

  Examples of the polyol (1) include diol (1-1) and trivalent or higher polyol (1-2). (1-1) alone or (1-1) and a small amount The mixture of (1-2) is preferable. Diol (1-1) includes 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 alicyclic diol; Examples include adducts of alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.). Of these, preferred are alkylene oxide adducts of alkylene glycols and bisphenols having 2 to 12 carbon atoms, and particularly preferred are alkylene oxide adducts of bisphenols and those having 2 carbon atoms. It is combined use with ˜12 alkylene glycol. The trivalent or higher polyol (1-2) includes 3 to 8 or higher polyvalent aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol. Trihydric or higher phenols (trisphenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or higher polyphenols.

Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). (2-1) alone and (2-1) with a small amount of ( The mixture of 2-2) is preferred. Dicarboxylic acids (2-1) 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, naphthalenedicarboxylic acid, etc.). 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 polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). The polycarboxylic acid (2) may be reacted with the polyol (1) using an acid anhydride or a lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) described above.
The ratio of the polyol (1) to the polycarboxylic acid (2) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate, etc.); alicyclic polyisocyanates -Toro (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); Aromatic diisocyanate (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); Aro-aliphatic diisocyanate (α , Α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; those polyisocyanates blocked with phenol derivatives, oximes, caprolactams, etc .; and two or more of these Combined use is mentioned.

  The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group, preferably Is 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 2%. 20% by weight. If it is less than 0.5% by weight, 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% by weight, the low-temperature fixability deteriorates.

The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to average. 2.5 pieces. If it is less than 1 per molecule, the molecular weight of the modified polyester will be low, and the hot offset resistance will deteriorate.
As amines (B), diamine (B1), triamine or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and amino groups of B1 to B5 are blocked. (B6) and the like. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine etc.) and the like. Examples of the trivalent or higher polyamine (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 B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines 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.

Furthermore, if necessary, the molecular weight of the modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
The ratio of the amines (B) is equivalent to the equivalent ratio [NCO] / isocyanate group [NCO] in the prepolymer (A) having an isocyanate group to the amino group [NHx] in the amines (B). [NHx] 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] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the modified polyester (i) may contain a urethane bond as well as 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 main peak molecular weight of the modified polyester is usually 1000 to 10000, preferably 2000 to 8000. When the amount of the component having a molecular weight of less than 1000 is increased, the heat resistant storage stability tends to be deteriorated, and when the component having a molecular weight of 10,000 or more is increased, the low-temperature fixability is simply decreased, but it is possible to suppress the decrease as much as possible by a balance control. . Further, the content of a polymer component having a molecular weight of 30000 or more is 1% to 10%, and preferably 3 to 6% although it varies depending on the toner material. If it is less than 1%, sufficient hot offset resistance cannot be obtained, and if it is 10% or more, the gloss and transparency are deteriorated.
Moreover, it leads to hot offset improvement by using the polyester resin which contains 1-25% of THF insolubles. In addition, the toner is further pulverized by contact stress caused by a developing roller, a toner supply roller, a layer thickness regulating blade, a frictional charging blade, and the like due to long-term stirring inside the one-component developing device. This is effective for problems such as generation of ultrafine particles and deterioration of image quality due to the fluidizing agent embedded in the toner surface. Although THF-insoluble matter is effective for hot offset in color toner, it is negative for gloss and transparency of OHP, but it is effective within 1 to 10% for widening the mold release width. There is also a case that demonstrates.

(Unmodified polyester)
Not only the modified polyester (i) can be used alone, but also this (i), unmodified polyester (ii) can be contained as a toner-binder component. By using (ii) in combination, the low-temperature fixability and glossiness when used in a full color apparatus are improved, which is preferable to single use. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i) above, and preferred ones are also the same as (i). Further, (ii) is not limited to unmodified polyester, but may be modified with, for example, a urea bond or a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) and (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.
The peak molecular weight of (ii) is usually 1000-20000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is preferably 10-30. By giving an acid value, it tends to be negatively charged, and the fixability tends to be further improved. However, when the acid value exceeds 30, particularly when used in a high temperature and high humidity environment, the toner charge amount may decrease, and problems such as background smearing on the image may occur.

  The glass transition point (Tg) of (ii) is 35 to 55 ° C, preferably 40 to 55 ° C. If it is less than 35, the heat resistant storage stability of the toner deteriorates, and if it exceeds 55 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester toners. As the storage elastic modulus of the toner binder, the temperature (TG ′) at which 10000 dyne / cm 2 is obtained at a measurement frequency of 20 Hz is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the toner binder, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or less, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

(Release agent)
Further, a wax may be contained together with the toner binder and the colorant. As a result of investigations by the present inventors, it has been clarified that the state of wax in the toner greatly affects the releasability of the toner at the time of fixing, and the wax is finely dispersed in the toner and the toner. It was revealed that a good fixing and releasing property can be obtained by being present in the vicinity of the surface and in the vicinity of the surface. In particular, it is preferable that the wax has a long diameter and is dispersed to 1 μm or less. However, when a large amount of the release agent is exposed on the toner surface, long-term agitation inside the developing device causes the wax to easily come off the toner surface, and adheres to the surface of the member in the developing device. Since it adheres and the charge amount of a developer may be reduced, it is not preferable. The dispersion of these release agents is judged from an enlarged photograph obtained using a transmission electron microscope.
Known waxes can be used, and examples thereof include polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long-chain hydrocarbons (paraffin wax, sazol wax, etc.); carbonyl group-containing waxes, and the like. Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenene. Polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenyl amide, etc.); polyalkylamides (Trimellitic acid tristearyl amide, etc.); and dialkyl ketones (distearyl ketone, etc.). Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of the wax of the present invention is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat-resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause cold offset during fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

(Charge control agent)
Any known charge control agent particles can be used. However, as mentioned above, salicylic acid metal salts and metal salts of salicylic acid derivatives are preferred. Specifically, E-84 (made by Orient Chemical Industry Co., Ltd.) of a salicylic acid metal complex is mentioned. A crystalline compound is preferable, and a compound that can be easily crushed into fine particles of 1 μm by stress or the like is more preferable. These charge control agent particles can also be placed in advance in resin particles containing a colorant for chargeability reinforcement.
(External additive)
Any known external additive using inorganic fine particles can be used. However, as described above, it is preferably selected from silica, titania, and alumina.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphtho-louero-S, Hansaero (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), permanentoyero (NCG) ), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow-BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Red, Cadmium Red, Cadmium Ma-Cury Red, Antimony Zhu, Permanent Red 4R, Para Red, Faucet Red, Parachlor Ortho Nitro Nilin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine 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, Bold-5B, Toluidine Marun, Permanent Bold-F2K, Heliobold-BL, Bold-10B, Bonmarite Light, Bonmarum Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Reazo Red, Chrome Bar Million, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cellulian Blue, Alkaline Bull Lake, Peacock Bull Lake, Victoria Bull Lake, no metal Phthalocyanine bull, Phthalocyanur bull, Fast sky bull, Indense lumble (RS, BC), Indigo, Ultramarine blue, Bitumen, Anthraquinone bull, 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, naphtho green B, green gold, acid green lake, Malachite green lake, phthalo Cyaning green, anthraquinone green, titanium oxide, zinc white, ritbon 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. The binder resin to be kneaded together with the production of the master batch or the master batch includes styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and its substitutes in addition to the modified and unmodified polyester resins mentioned above. Polymer: Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate Copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene -Α-chloromethyl methacrylate copolymer, Tylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-malein Styrenic copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, Examples include polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, and paraffin wax. Can be used alone or in combination The
In this master batch, a master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shearing force. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. In addition, the so-called flushing method is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. -Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

The shape of the toner used in the image forming apparatus of the present invention is a substantially spherical shape, and can be represented by the following shape rule.
FIG. 5 is a diagram schematically showing the shape of the toner according to the present invention. In (a), 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 The ratio to the minor axis (r2 / r1) (see (b)) is 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) (see (c)) is 0.7 to 1. Preferably it is in the range of 0.0. 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, when the ratio of thickness to minor 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.

  FIG. 6 is a schematic cross-sectional view showing the configuration of the process cartridge taken out from the main body of the image forming apparatus. In the image forming apparatus 1 of the present invention, the photosensitive member 5 and one or more devices selected from the coating device 16, the charging device 14, the developing device 10, and the cleaning device 15 are integrally supported and detachable. A process cartridge is provided. Accordingly, the developer and the developing device 10 can be easily replaced, and the main body of the image forming apparatus 1 can be used over a long period of time.

The dry toner used in the image forming apparatus of the present invention can be manufactured by the following method, but is not limited thereto.
(Manufacturing method of toner in aqueous medium)
The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (e.g., methyl cellosolve), lower ketones (e.g., acetone, methyl ethyl ketone), etc. Is mentioned.
As a method for stably forming a dispersion composed of the prepolymer (A) and the unmodified polyester (ii) in the aqueous medium, the prepolymer (A) and the unmodified polyester (ii) are formed in the aqueous medium. Examples thereof include a method of adding a toner raw material composition and dispersing it by shearing force. The prepolymer (A), unmodified polyester (ii) and other toner compositions (hereinafter referred to as toner raw materials) colorants, colorant master batches, mold release agents, charge control agents, Although mixing may be performed when forming the dispersion in the medium, it is more preferable to mix the toner raw material in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium. It may be added later. For example, after forming particles that do not contain a colorant, the colorant can be added by a known dyeing method.

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. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. 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. Higher temperatures are preferable in that the dispersion made of the modified polyester (i) or the prepolymer (A) has a low viscosity and is easily dispersed.
The amount of the aqueous medium used is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight based on 100 parts of the toner composition containing the prepolymer (A) and the unmodified polyester (ii). If the amount is less than 50 parts by weight, the toner composition is not well dispersed, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used with resin fine particles as needed. The use of a dispersant is preferred in that the particle size distribution becomes sharp and the dispersion is stable.
The step of synthesizing the urea-modified polyester from the prepolymer (A) may be carried out by adding amines (B) before dispersing the toner composition in the aqueous medium, or after dispersing in the aqueous medium. A reaction may be caused from the particle interface by adding the compound (B). In this case, urea-modified polyester is preferentially produced on the surface of the toner to be produced, and a concentration gradient can be provided inside the particles.

  As an dispersant for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water, anionic surface active soot such as alkylbenzene sulfonate, α-olefin sulfonate, and phosphate ester, alkyl Amine salt types such as amine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, chlorides Quaternary ammonium salt type cationic surfactants such as benzethonium, nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine And N-alkyl N, amphoteric surfactants such as N- dimethyl ammonium betaine and the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms and a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 31- [omega-fluoroalkyl (C6 -C11) oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) mono-N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) ) Carboxylic acid and metal salt, perfluoroalkylcarboxylic acid (C7 to C13) and its metal salt, perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, perfluorooctanesulfonic acid diethylanolamide N-propyl-N- (2hydroxyethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, mono-fluoroalkyl (C6-C16) ethyl phosphoric acid Such as esters,
As product names, Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florad FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS 1-101, DS-102 (manufactured by Taikin Kogyo Co., Ltd.), Mega-Fac F-l10, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Ektop EF-1 102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), Phgent F-100, F150 (manufactured by Neos), etc. Can be mentioned.
Further, as the cationic surfactant, aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6C10) sulfonamidopropyltrimethylammonium salt which right the fluoroalkyl group , Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, as trade names, Surflon S-121 (manufactured by Asahi Glass Co., Ltd.), Florad FC-135 (manufactured by Sumitomo 3M Company), Unidyne DS-202 (Manufactured by Daikin Industries Co., Ltd.), MegaFuck F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), Phgentent F1300 (manufactured by Neos), etc. Is mentioned.

Moreover, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite, etc. can be used as an inorganic compound dispersant which is hardly soluble in water.
Further, it is particularly preferable to stabilize the dispersed droplets with a polymer protective colloid. For example, (meth) acrylic acid containing acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, or a hydroxyl group Monomers such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, acrylic acid 3-chloro-2-hydroxypropyl, 3-chloro-2-monohydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N Ethers with vinyl alcohol or vinyl alcohol, such as methylol acrylamide, N-methylol methacrylamide, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or vinyl alcohol Esters of compounds containing a carboxyl group, for example, pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride , Homopolymers or copolymers such as those having a nitrogen atom such as pinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethylene imine, or a heterocyclic ring thereof, polyoxyethylene, polyoxypropylene, polyethylene Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, poly Polyoxyethylenes such as oxyethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like can be used.
In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation.
When a dispersant is used, the dispersant can remain on the surface of the toner particles. However, it is preferable from the charged surface of the toner that the dispersant is washed away after the elongation and / or crosslinking reaction.

Further, in order to lower the viscosity of the toner composition, a solvent in which the prepolymer (A) and the unmodified polyester (ii) are soluble can be used. The use of a solvent is preferable in that the particle size distribution is sharpened. The solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal. Examples of the solvent include 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 the solvent with respect to 100 parts of prepolymer (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after the elongation and / or crosslinking reaction.
The elongation and / or crosslinking reaction time is selected depending on the reactivity depending on the combination of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24. It's time. The reaction temperature is usually 0 to 150 ° C, preferably 5 to 50 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

In order to remove the organic solvent from the obtained emulsified dispersion, a method can be employed in which the temperature of the entire system is gradually raised and the organic solvent in the droplets is completely evaporated and removed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation. is there. As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide, combustion gas, or the like, particularly various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient target quality can be obtained by short-time processing such as spray dryer, belt dryer, rotary kiln and the like.
When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution.
In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying.
The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

Mix the resulting toner powder after drying with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or give mechanical impact force to the mixed powder. By immobilizing and fusing on the surface, it is possible to prevent detachment of foreign particles from the surface of the resulting composite particle.
Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Numatic Co., Ltd.) was modified to reduce pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), A kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), an automatic mortar, etc.

1 is a schematic diagram illustrating a configuration of an image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of an image forming unit in the image forming apparatus of the present invention. It is the schematic which shows the contact conditions of a cleaning blade. It is the figure which represented typically the shape of the toner in order to demonstrate shape factor SF-1 and shape factor SF-2. It is a figure which shows typically the shape of the toner which concerns on this invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a process cartridge taken out from the image forming apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming unit 21 Process cartridge 3 Transfer apparatus 31 Transfer belt 5 Photoconductor (Image carrier)
6 Exposure device 7 Double-side unit 8 Reversing unit 9 Fixing device 10 Developing device 11, 12 Paper feed cassette 13 Manual feed tray 14 Charging device 141 Charging roller 142 Charging roller cleaning brush 15 Cleaning means 151 Cleaning blade 152 Blade pressure spring 153 Blade rotation Support point 154 Cleaning blade support 155 Waste toner collecting coil 158 Brush roller scraper 16 Coating device 161 Brush roller 162 Lubricant molding 163 Bar pressure spring 20 Reverse paper discharge path 25 Roller pair 26 Paper discharge trays 45a and 45b Transport guide Plate 46 Conveying rollers 55 and 56 Separating paper feeding unit 58 Paper adsorbing roller 59 Registration roller pair

Claims (19)

An image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, an exposure device that exposes the charged image carrier surface based on image data and writes the latent image, and an image carrier A developing device that supplies toner to the latent image formed on the surface and visualizes the image; a transfer device that transfers the visible image on the surface of the image bearing member directly or onto an intermediate transfer member; An image forming apparatus comprising: a cleaning device that cleans a carrier or an intermediate transfer member; and a fixing device that fixes a toner image on a recording medium.
The image forming apparatus includes a detecting unit that detects a friction coefficient of the surface of the image carrier or the intermediate transfer member;
An image forming apparatus comprising: an adjusting unit that adjusts a cleaning condition of the image bearing member or the intermediate transfer member based on a friction coefficient detected by the detecting unit. The image forming apparatus according to claim 1.
The image forming apparatus characterized in that the detection means detects a friction coefficient by measuring a driving torque of the image carrier or the intermediate transfer member. The image forming apparatus according to claim 1.
The image forming apparatus characterized in that the detecting means detects a friction coefficient by measuring a current of a motor that drives the image carrier or the intermediate transfer member. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the cleaning device includes a cleaning blade. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the cleaning device adjusts a contact pressure of a cleaning blade. The image forming apparatus according to claim 4, wherein
The image forming apparatus, wherein the cleaning device adjusts a contact angle of a cleaning blade. The image forming apparatus according to any one of claims 4 to 6,
The image forming apparatus, wherein the cleaning device adjusts a contact amount of a cleaning blade. The image forming apparatus according to any one of claims 4 to 7,
In the image forming apparatus, the coefficient of friction of the image carrier is 0.1 or more. The image forming apparatus according to claim 8.
In the cleaning device, when the friction coefficient μ of the image carrier is less than 0.1, the contact pressure Y of the cleaning blade is set to 0.1 N / cm or more,
When the friction coefficient μ of the image carrier is 0.1 or more, Y (N / cm) ≧ k × μ (k: 1 as a proportional coefficient)
The image forming apparatus is adjusted so as to satisfy the relationship. The image forming apparatus according to claim 1,
The image forming apparatus uses a toner having a volume average particle diameter of 10 μm or less and a ratio (dispersity) of the volume average particle diameter to the number average particle diameter in the range of 1.00 to 1.40. An image forming apparatus. The image forming apparatus according to claim 10.
The image forming apparatus, wherein the image forming apparatus uses toner having an average circularity in a range of 0.93 to 1.00. The image forming apparatus according to claim 10 or 11,
The image forming apparatus has an almost spherical appearance.
The ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0. An image forming apparatus comprising: a toner satisfying a relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3. The image forming apparatus according to any one of claims 10 to 12,
The image forming apparatus crosslinks and / or extends a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of resin fine particles. An image forming apparatus using the toner to be used. The image forming apparatus according to claim 1,
The charging device includes a roller-shaped charging member that is not in contact with the image carrier. The image forming apparatus according to any one of claims 1 to 14,
The image forming apparatus includes a process cartridge that integrally supports at least the image carrier and the cleaning device and is detachable from the main body of the image forming apparatus. An image carrier that forms a latent image, a charging device that uniformly charges the surface of the image carrier, an exposure device that exposes the charged image carrier surface based on image data and writes the latent image, and an image carrier A developing device that supplies toner to the latent image formed on the surface and visualizes the image; a transfer device that transfers the visible image on the surface of the image bearing member directly or onto an intermediate transfer member; A cleaning device for cleaning the carrier or the intermediate transfer member; and a fixing device for fixing the toner image on the recording medium. The image forming device detects a friction coefficient of the surface of the image carrier or the intermediate transfer member. In a toner used for an image forming apparatus, comprising: a detecting unit that adjusts a cleaning condition of an image carrier or an intermediate transfer member according to a friction coefficient detected by the detecting unit;
The toner is characterized by using a toner having a volume average particle size of 10 μm or less and a ratio (dispersity) of the volume average particle size to the number average particle size in the range of 1.00 to 1.40. toner. The toner according to claim 16.
The toner has an average circularity in a range of 0.93 to 1.00. The toner according to claim 16 or 17,
The toner has a substantially spherical appearance,
The ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0. And a toner satisfying the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3. The toner according to any one of claims 16 to 18,
A toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is crosslinked and / or extended in the presence of resin fine particles in an aqueous medium. Toner.

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