JP2016110061A - Cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: it has been demanded that, when a developer remaining after transfer passes between an image carrier and a charging member, the occurrence of cracks in and deformation of the developer is suppressed, and images with stable quality can be obtained for a long period.SOLUTION: When the Martens hardness of the surface of a charging member is HMR, and the Martens hardness of the surface of a developer is HMD, the relationship HMD>HMR is established.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium and a cartridge that is detachable from the image forming apparatus.

  Conventionally, in an image forming apparatus such as an electrophotographic system, a cleanerless system (toner recycling system) has been proposed from the viewpoint of simplifying the configuration of the apparatus and eliminating waste. This cleaner-less system eliminates a dedicated drum cleaner, which is a means for cleaning the photosensitive drum after transfer, and removes transfer residual toner on the photosensitive drum after transfer from the photosensitive drum by "development simultaneous cleaning" by the developing device. Thus, it is a method of collecting and reusing the developing device. Simultaneous development cleaning is a fog removal bias (fogging removal potential difference Vback which is a potential difference between the DC voltage applied to the developing device and the surface potential of the photosensitive drum) during toner development after the next process. ). According to this method, since the transfer residual toner is collected by the developing device and reused after the next step, waste toner can be eliminated and the maintenance work can be reduced. Further, the cleanerless system has a great space advantage, and the image forming apparatus can be greatly downsized.

  In the cleanerless system (toner recycling system) described above, a contact charging method in which the photosensitive drum is uniformly charged by contacting the photosensitive drum may be adopted. However, the contact charging method may cause the following problems.

  In the contact charging method, since the charging roller is pressed against the photosensitive drum, when the toner remaining after the transfer passes through the contact portion between the photosensitive drum and the charging roller, both are crushed and cracked. And could cause deformation. Since the toner remaining after the transfer is discrete and isolated, the load received at the contact portion between the photosensitive drum and the charging roller is large, and the toner is liable to be cracked or deformed. Because irregularly shaped toner that is cracked or deformed is difficult to have a uniform charge, the charging roller is soiled due to deterioration in developability, transferability, recoverability, etc., and image defects such as poor charging are likely to occur. Become. Furthermore, since irregularly shaped toner is difficult to be transferred, in a cleanerless system (toner recycling system), the toner is repeatedly consumed and collected, and the amount of irregularly shaped toner in the developing device increases. As a result, as the toner is consumed due to long-term durability, it is likely to cause image deterioration due to the deterioration of the fluidity of the toner and the inability to hold the charge of the toner.

  As a cleanerless system employing a conventional contact roller charging system, three patent documents have been proposed in order to solve the problems described above. Japanese Patent Application Laid-Open No. 2004-228561 suppresses the deformation rate of toner that has passed through a contact portion between a photosensitive drum and a charging roller, and provides a stable image over a long period of time. Patent Documents 2 and 3 define the circularity, amount, and specific charge of toner, and are intended to suppress image problems such as fogging.

JP 2003-162085 A JP 2005-173485 A JP 2006-154093 A

  However, with the configurations of Patent Documents 1, 2, and 3, there is a possibility that good image quality cannot be obtained over a long period of time. With respect to Patent Document 1, the toner shape change rate is defined, but it is disclosed that it can be controlled by appropriately selecting the configuration of the layers constituting the charging roll and the material and thickness of these layers. There is only. Further, regarding Patent Documents 2 and 3, a configuration for improving deterioration in developability and recovery in recovery has been proposed, but the problem of further improving the durability remains in these cases.

  The present invention is a further development of the above-described conventional technique. The purpose of the present invention is to break or deform the developer when the developer remaining after the transfer passes between the image carrier and the charging member. To obtain images with stable quality over a long period of time.

  In order to achieve the above object, the present invention provides an image carrier, a charging member that contacts the image carrier and charges the image carrier, and a developer member that contacts the image carrier and supplies developer. In the image forming apparatus that collects the developer remaining on the image carrier after transfer by the developing member, the Martens hardness of the surface of the charging member is HMR, and the Martens hardness of the surface of the developer is When HMD is HMD, the relationship is HMD> HMR.

  Further, the present invention is detachable from the image forming apparatus, and includes an image carrier, a charging member that contacts the image carrier and charges the image carrier, and a developer that contacts the image carrier. A developing member to be supplied, and a cartridge that collects the developer remaining on the image carrier after transfer by the developing member, wherein the Martens hardness of the surface of the charging member is HMR, and the Martens hardness of the surface of the developer is When the hardness is HMD, the relationship is HMD> HMR.

  According to the present invention, even if the developer remaining on the image bearing member after transfer passes between the image bearing member and the charging member, the charging member is softer than the developer and thus easily deforms and is applied to the developer. Since the burden is alleviated, it is possible to reduce cracking and deformation of the developer.

Schematic cross-sectional view showing schematic configuration of image forming apparatus The figure which shows the charging roller and the weighted dent depth curve of a toner in Example 1. FIG. (A) and (b) are diagrams showing deformation of toner passing between a charging roller and a photosensitive member. (A) is a diagram showing a toner observation image after acceleration evaluation in Example 1, and (b) is a diagram showing a toner observation image after acceleration evaluation in Comparative Example 1. The figure which compares the Martens hardness of Example 4 and Comparative Example 3 Schematic sectional view showing a schematic configuration of an image forming apparatus in which a drum cartridge and a developing cartridge are detachable

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. The examples described below illustrate the present invention by way of example, and the dimensions, materials, shapes, relative arrangements, etc. of the components described below are not particularly specified unless otherwise specified. However, the scope of the present invention is not limited thereto.

  FIG. 1 is a schematic cross-sectional view showing a schematic configuration of the image forming apparatus. The image forming apparatus exemplified here is a monochrome laser printer using a transfer type electrophotographic process.

  The photosensitive drum 1 as an image carrier is a negative OPC photosensitive member having a diameter of 24 mm in this example. The photosensitive drum 1 is rotationally driven in the clockwise direction in the drawing at a constant speed of 100 mm / sec (= process speed PS, printing speed).

  A charging roller 2 as a charging member is disposed in contact with the photosensitive drum 1 and charges the surface of the photosensitive drum 1 which is the surface of the image carrier. The charging roller 2 is pressed against the photosensitive drum 1 with a predetermined pressing force (here, 600 gf at the time of driving) to form a charging nip portion c between the charging roller 2 and the photosensitive drum 1. In this example, the charging roller 2 is driven to rotate relative to the rotation of the photosensitive drum 1. There is a charging power source as a voltage applying means for applying a charging bias to the charging roller 2. In this example, a DC voltage is applied from the charging power source to the metal core 2a. The DC voltage to be applied is set to a value such that the potential difference between the surface of the photosensitive drum 1 and the charging roller 2 is equal to or higher than the discharge start voltage. Specifically, a DC voltage of -1300 V is applied as a charging bias. Yes. At this time, the surface of the photosensitive drum 1 is uniformly contact-charged to a charged potential (dark portion potential) of −700V.

  As exposure means for forming an electrostatic latent image on a charged image carrier, there is a laser beam scanner 4 including a laser diode and a polygon mirror. This laser beam scanner 4 outputs a laser beam whose intensity is modulated in accordance with the time-series electric digital pixel signal of the target image information, and scans the uniformly charged surface of the photosensitive drum 1 with the laser beam L. Exposure. When the entire charging surface of the photosensitive drum 1 is exposed with the laser beam L, the laser power is adjusted so that the potential of the surface of the photosensitive drum 1 becomes −150V.

  A developing device 3 as a developing unit having a developing member supplies a developer to the electrostatic latent image formed on the photosensitive drum 1. Development can be performed by a developing sleeve as a developing member to which a developing bias (Vdc) of -350 V is applied from a developing bias power source (not shown) as voltage applying means for applying a voltage to the developing member.

  Here, the developing device 3 will be described. The developing sleeve 31 is rotatably supported by the developing device 3 and is rotationally driven with respect to the photosensitive drum 1 at a peripheral speed of 140%. The developing sleeve 31 is provided with a conductive elastic rubber layer around a hollow aluminum tube, and the surface of the conductive elastic rubber layer has a surface roughness Ra of 1.0 μm to 2.0 μm for conveying the developer. Roughness is provided. A magnet roller 32 is fixedly disposed in the developing sleeve 31. The magnetic one-component black developer (negative charging characteristic) T as the developer in the developing device 3 is stirred by the stirring member 34 in the developing device. The developer T is supplied to the surface of the developing sleeve 31 by the magnetic force of the magnet roller 32 in the developing device 3 by this stirring. The developer supplied to the surface of the developing sleeve 31 passes through the developing blade 33 that is in contact with the developing sleeve, and is uniformly thinned, and is negatively charged by frictional charging. Thereafter, the developer on the surface of the developing sleeve 31 is transported to a developing position (contact position) where it contacts the photosensitive drum 1 and develops the electrostatic latent image on the photosensitive drum 1.

A medium resistance transfer roller 5 as a transfer means (contact transfer means) is pressed against the photosensitive drum 1 with a predetermined pressing force to form a transfer nip portion b between the photosensitive drum 1. The transfer roller 5 transfers the developer image on the photosensitive drum 1 visualized by the developing unit to the transfer material P fed from the cassette 70 by the feed roller 71. The transfer roller 5 used in this example has a roller resistance value of 5 × 10 ⁸ Ω, in which a medium resistance foam layer 5b is formed on a core metal 5a, and a voltage of +2.0 kV is applied to the core metal 5a for transfer. Went.

  There is a heat fixing type fixing device 6 as a fixing means. The transfer material P that has passed the transfer nip portion b and has received the transfer of the toner image is separated from the surface of the photosensitive drum 1 and introduced into the fixing device 6, where the toner image is fixed and an image formed product (print As a copy).

  In this example, the developer remaining on the image carrier after the transfer by the transfer means is collected by the developing means simultaneously with the development. That is, a so-called cleanerless system is employed in which a cleaning member for removing transfer residual toner remaining on the photosensitive drum 1 without being transferred from the photosensitive drum 1 is not provided. Hereinafter, a cleanerless system that collects the developer remaining on the surface of the photosensitive drum 1 after the transfer using the developing sleeve 31 will be described in detail.

  The transfer residual toner remaining on the photosensitive drum 1 after the transfer step is negatively charged in the same manner as the photosensitive drum 1 due to discharge in the gap portion before the contact portion (charging nip portion c) between the charging roller 2 and the photosensitive drum 1. It is charged with nature. At this time, the surface of the photosensitive drum 1 is charged to −700V. The transfer residual toner charged to the negative polarity passes through the charging nip portion c without adhering to the charging roller 2 due to the potential difference (photosensitive drum surface potential = −700 V, charging roller potential = −1300 V).

  The untransferred toner that has passed through the charging nip c reaches the laser irradiation position. Since the transfer residual toner is not so large as to block the laser beam L of the exposure unit, it does not affect the process of forming an electrostatic latent image on the photosensitive drum 1. The toner that has passed through the laser irradiation position d is in the non-exposed portion (photosensitive drum surface not receiving laser irradiation) at the contact portion (developing nip portion a) between the developing sleeve 31 and the photosensitive drum 1. The developing sleeve 31 is recovered by electric power. On the other hand, the toner on the exposed portion (photosensitive drum surface subjected to laser irradiation) continues to be present on the photosensitive drum 1 as it is without being recovered electrostatically. However, a part of the toner may be collected by a physical force due to a difference in peripheral speed between the developing sleeve 31 and the photosensitive drum 1.

  Thus, the transfer residual toner that is not transferred to the transfer material P and remains on the photosensitive drum 1 is generally collected by the developing device 3. The toner collected in the developing device 3 is mixed with the toner remaining in the developing device 3 and reused.

  In the present invention, in order to pass the transfer residual toner through the charging nip c without adhering to the charging roller 2, the charging roller 2 is driven and rotated with a predetermined peripheral speed difference from the photosensitive drum 1. By driving and rotating the charging roller 2 and the photosensitive drum 1 with a predetermined peripheral speed difference, it is possible to make such toner negative by sliding between the photosensitive drum 1 and the charging roller 2. Become. This has an effect of suppressing the adhesion of toner to the charging roller 2. In the present invention, a charging roller gear is provided on the metal core 2a of the charging roller 2, and the charging roller gear is engaged with a drum gear provided at the end of the photosensitive drum. Therefore, as the photosensitive drum 1 is driven to rotate, the charging roller 2 is also driven to rotate. The peripheral speed of the surface of the charging roller 2 is set to 115% with respect to the peripheral speed of the surface of the photosensitive drum 1. Note that the rotation direction of the charging roller 2 is set to the same direction at the point of contact with the photosensitive drum 1. Further, it is effective to set the peripheral speed of the charging roller 2 to 101% or more, preferably 105% or more, and the practical range is 200% or less, preferably 150% or less.

  In the image forming apparatus according to the present invention, the transfer residual toner is discretely scattered, and the toner is basically isolated. For this reason, a heavy load is required when passing between the photosensitive drum and the charging roller, and irregularly shaped toner may be generated due to cracking or deformation.

  By providing the peripheral speed difference as described above, the charging of the photosensitive drum can be improved, and the adhesion of toner to the charging roller can be reduced. However, from the viewpoint of untransferred toner, the burden when passing between the photosensitive drum and the charging roller is further increased. In the case where the peripheral speed difference is provided, there is a further problem to be solved such as generation of irregularly shaped toner.

  If the rotation direction of the charging roller 2 is set to the same direction at the point of contact with the photosensitive drum 1, it is possible to further improve the charging of the photosensitive drum or reduce the adhesion of toner to the charging roller. It is a configuration. However, from the viewpoint of untransferred toner, the burden when passing between the photosensitive drum and the charging roller is further increased. Therefore, the above-described problem becomes even greater.

  Therefore, in the present invention, the relationship between the Martens hardness HMR of the surface of the charging roller as the charging member and the Martens hardness HMD of the surface of the toner as the developer is set to a relationship of HMD> HMR.

  By doing so, even if the transfer residual toner passes through the contact portion between the photosensitive drum 1 and the charging roller 2, the surface of the charging roller 2 is more than the toner t as shown in FIG. Deform first. At this time, as shown in FIG. 3A, the toner t remaining on the photosensitive drum 1 bites into the surface of the charging roller 2 at the contact position (charging nip portion c) with the photosensitive drum 1. Deform. Thereby, since the deformation of the toner t is relieved, the cracking and deformation of the toner t can be suppressed. On the other hand, when the charging roller 2 is harder than the toner, the toner t is deformed earlier than the charging roller 2 as shown in FIG. 3B, and the toner t is likely to be broken or chipped. Further, a sufficient effect can be exhibited even under a condition where a peripheral speed difference is provided between the photosensitive drum and the charging roller.

  Therefore, it is necessary to adjust the developer in the present invention to a predetermined Martens hardness as described above. When a negatively chargeable magnetic one-component toner is used as a developer, it can be produced as follows.

  In the present invention, the Martens hardness (hardness), which is a minimum indentation depth of 1 μm, is controlled. In order to obtain a developer suitable for the present invention, it is necessary to control the hardness of the particles constituting the developer, in the above case, the magnetic one-component toner particles contained in the developer.

  In order to obtain a magnetic one-component toner having a desired Martens hardness, the following method can be used. One of them is controlling the material, composition or molecular weight of the binder resin of the magnetic one-component toner. Furthermore, it can be controlled by appropriately providing a shell layer on the surface of the magnetic one-component toner base. Furthermore, it can be controlled by appropriately selecting a softening material such as wax or a colorant and an inorganic pigment containing magnetic powder contained in the magnetic one-component toner particles.

  If the Martens hardness HMD of the toner surface is too small, there is a possibility that it becomes difficult to use, such as an increase in adhesion. Further, if the Martens hardness HMD of the toner surface is too large, problems such as damage to the photosensitive drum are likely to occur. Accordingly, the Martens hardness HMD of the toner surface is preferably 2 or more, more preferably 2.5 or more, from the viewpoint of adhesion. Further, the Martens hardness HMD of the toner surface is preferably 50 or less, more preferably 20 or less, more preferably 15 or less in relation to the surface layer of the photosensitive drum.

  On the other hand, the charging roller used in the image forming apparatus of the present invention also needs to have a predetermined Martens hardness. In order to make the charging roller have a predetermined Martens hardness, for example, the surface layer of the charging roller and the material in the vicinity thereof, the composition, the molecular weight, or the degree of crosslinking can be controlled. Furthermore, it can be controlled by adding a hard or soft material to the surface layer of the charging roller.

  If the Martens hardness HMR on the surface of the charging roller is too small, the tackiness may be increased and the torque may be increased, which may make it difficult to use. On the other hand, if the Martens hardness HMR on the surface of the charging roller is too large, there is a possibility of causing a harmful effect such as damaging the photosensitive drum. Therefore, the Martens hardness HMR on the surface of the charging roller is preferably 0.5 or more, more preferably 1 or more, from the viewpoint of tackiness or torque. The Martens hardness HMR on the surface of the charging roller is preferably 19 or less, more preferably 10 or less, from the viewpoint of damaging the photosensitive drum.

  Furthermore, if the arithmetic average roughness Ra on the surface of the charging roller is too small, the tackiness is increased, and there is a possibility that it becomes difficult to use such as an increase in torque. Further, if the arithmetic average roughness Ra of the surface of the charging roller is too large, the surface hardness of the charging roller may be uneven, and the toner may be broken. Therefore, the arithmetic average roughness Ra of the charging roller surface is preferably 0.1 μm or more, and more preferably 0.6 μm or more, from the viewpoint of tackiness or torque. The arithmetic average roughness Ra of the charging roller surface is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of unevenness of the surface hardness of the charging roller. Further, the difference from the Martens hardness of the toner is preferably 1 or more, more preferably 3 or more. The arithmetic average roughness Ra is measured according to JIS B 0601: 2001.

  The toner and the charging roller used in the present invention and the comparative example are adjusted as follows. Hereinafter, an example of toner production and an example of production of a charging roller will be described.

[Toner Production Example 1]
-Styrene 75 parts by mass-n-butyl acrylate 25 parts by mass-Divinylbenzene 0.50 parts by mass-Saturated polyester resin 8 parts by mass (reaction product of terephthalic acid and bisphenol A ethylene oxide adduct, number average molecular weight = 4000 (Mw / Mn = 2.8, acid value = 11 mg / KOH)
Magnetic powder 80 parts by mass (surface treated with n-hexyltrimethoxysilane, volume average diameter 0.2 μm, saturation magnetization 70 Am2 / kg under magnetic field 79.6 kA / m)
-Resin having a sulfonic acid group 1.5 parts by weight (styrene 83 parts by weight n-butyl acrylate 12 parts by weight 2-acrylamido-2-methylpropane sulfonic acid 5 parts by weight copolymer, weight average molecular weight 23000)
Paraffin wax (maximum endothermic peak in DSC 78 ° C.) 10 parts by mass Polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) 5 parts by mass

  The above was uniformly dissolved and dispersed according to a conventional method, and charged into 750 parts by mass of ion-exchanged water having a dispersant, and granulated. Thereafter, the mixture was dried after the reaction, cooling, and removal of the dispersant to obtain a toner base. The prepared toner base has a polyester layer on the surface layer.

To 100 parts by mass of the toner base, 1.0 part by mass of hydrophobic silica fine powder having a BET value of 120 m ² / g was externally added to obtain a magnetic toner having a weight average particle diameter of 7.9 μm. The average circularity is 0.975. When the Martens hardness of the magnetic toner of this production example was measured, it was HM11.

[Toner Production Example 2]
In the toner production example 1, a toner base was obtained in the same manner as in the toner production example 1 except that 3 parts by mass of the saturated polyester resin was used.

To 100 parts by mass of the toner base, 1.0 part by mass of hydrophobic silica fine powder having a BET value of 120 m ² / g was externally added to obtain a magnetic toner having a weight average particle diameter of 7.5 μm. The average circularity is 0.977. When the Martens hardness of the magnetic toner of this production example was measured, it was HM5.0.

[Toner Production Example 3]
-80 parts by mass of styrene-20 parts by mass of n-butyl acrylate-0.3 parts by mass of polymethacrylic acid ester macromer (Mn = 6000)-0.30 parts by mass of divinylbenzene-80 parts by mass of magnetic powder (surface is n-hexyltri (Saturated magnetization 70Am2 / kg under surface treatment with methoxysilane, volume average diameter 0.2μm, magnetic field 79.6kA / m)
Resin having a sulfonic acid group 1.0 part by mass (styrene 83 parts by mass n-butyl acrylate 12 parts by mass 2-acrylamido-2-methylpropane sulfonic acid 5 parts by mass copolymer, weight average molecular weight 23000)
・ 6.0 parts by mass of dipentaerythritol hexamyristate (maximum endothermic peak 66 ° C. in DSC) 6 parts by mass of polymerization initiator t-butylperoxyisobutyrate

  The above was uniformly dissolved and dispersed according to a conventional method, and charged into 750 parts by mass of ion-exchanged water having a dispersant, and granulated. Then, it was made to react and the slurry was obtained.

  The following were mixed to obtain a water methyl methacrylate dispersion.

・ Methyl methacrylate 2 parts by mass ・ Ion-exchanged water 65 parts by mass

  The following was added to the slurry and allowed to react. A layer of polymethyl methacrylate is formed on the mother particles of the obtained toner.

-67 parts by mass of the above water methyl methacrylate dispersion-0.3 parts by mass of 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide]

To 100 parts by mass of the toner base material, 1.0 part by mass of hydrophobic silica fine powder having a BET value of 120 m ² / g was externally added and mixed to obtain a magnetic toner having a weight average particle diameter of 7.6 μm. The average circularity is 0.972. When the Martens hardness of the magnetic toner of this production example was measured, it was HM2.1.

[Toner Production Example 4]
The toner having HM19 was produced by the suspension polymerization method as follows.

  A toner base was obtained in the same manner as in Toner Production Example 1 except that the saturated polyester resin was changed to 15 parts by mass in Toner Production Example 1.

To 100 parts by mass of the toner base, 1.0 part by mass of hydrophobic silica fine powder having a BET value of 120 m ² / g was externally added to obtain a magnetic toner having a weight average particle diameter of 7.8 μm. When the Martens hardness of the magnetic toner of this production example was measured, it was HM19.

[Charging roller production example 1]
・ Butadiene-acrylonitrile rubber (trade name: Nipol DN-219: Nippon Zeon Co., Ltd.) 100 parts by mass. Plasticizer (sebacic acid-polypropylene glycol copolymer: Mn = 8000) 7 parts by mass. Stearic acid 1.2 parts by mass. Oxidation 5 parts by mass of zinc and 45 parts by mass of carbon black (Toka Black # 7360SB: Tokai Carbon Co., Ltd.)

  The above was mixed with a mixer, and the following was added and kneaded with an open roll to obtain an NBR kneaded product.

・ Sulfur 1 part ・ Tetrabenzylthiuram disulfide 3 part

  Next, the NBR kneaded product was extruded into an outer cylinder with an outer diameter of 10.5 mm and an inner diameter of 4.5 mm using an extruder, cut into a length of 250 mm, and steam steam at a temperature of 160 ° C. using a steam vulcanizer. In this, primary vulcanization was performed for 40 minutes to obtain a rubber primary vulcanization tube for a conductive elastic layer.

  Next, a conductive support obtained by applying a thermosetting adhesive to a central portion 231 mm of a steel cylinder (surface is nickel-plated) having a diameter of 5 mm and a length of 256 mm and drying at 80 ° C. for 10 minutes, Inserted into a rubber primary vulcanization tube. Then, it heat-processed in 150 degreeC electric oven for 1 hour, and obtained the unpolished roller.

  Both ends of the rubber part of the unpolished roller were cut off to make the length of the rubber part 232 mm, and then the rubber part was polished with a rotating grindstone to obtain a conductive substrate having a diameter of 9 mm.

・ 100 parts by mass of 8-nylon (N-methoxymethylated nylon: trade name Toresin EF30T Teikoku Chemical Industry Co., Ltd.) ・ 10 parts by mass of carbon black (trade name Denka Black (registered trademark) Denki Kagaku Kogyo) ・ 1 part by mass of citric acid・ Methanol 350 parts by massToluene 150 parts by mass

  The above mixture was dispersed and mixed with a ball mill and filtered to obtain a coating solution.

  The above coating solution is coated on the conductive substrate by a roll coating method, air-dried, then dried at 60 ° C. for 1 hour, and subjected to a crosslinking reaction at 130 ° C. for 30 minutes to form a 15 μm surface layer. did.

  The Martens hardness of the charging roller of this production example was HM3.0, and the MD-1 hardness was 62. The arithmetic average roughness Ra is 2.1 μm.

[Charging roller production example 2]
A charging roller 2 having a 13 μm surface layer was obtained in the same manner except that 0.5 parts by mass of citric acid was used in the charging roller production example 1.

  The Martens hardness of the charging roller 2 of this production example was HM2.5, and the MD-1 hardness was 62. The arithmetic average roughness Ra is 2.0 μm.

[Charging roller production example 3]
The conductive substrate was obtained in the same manner as in charging roller production example 1.

• 100 parts by mass of acrylic silicone polymer (trade name Modiper FS700: manufactured by NOF Corporation) • 40 parts by mass of carbon black (trade name Denka Black (registered trademark) Denki Kagaku Kogyo) • 500 parts by mass of ethyl acetate

  The above mixture was dispersed and mixed with a ball mill and filtered to obtain a dispersion. The following was added to the dispersion and mixed to obtain a coating solution.

・ Diphenylmethane diisocyanate 10 parts by mass

  The said coating liquid was coated on the said electroconductive base | substrate with the roll-coating method, and it heated at 120 degreeC for 1 hour after air drying. The thickness of the surface layer is 20 μm.

  The Martens hardness of the charging roller of this production example was HM13.4, and the MD-1 hardness was 61. The arithmetic average roughness Ra is 2.1 μm.

  The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particle. In the present invention, the particle shape of the particle shape is measured using a flow type particle image analyzer FPIA-2100 manufactured by Toa Medical Electronics. Measurement is performed, and the circularity is obtained by the following equation 1. Furthermore, as shown by the following formula 2, a value obtained by dividing the total circularity of all the measured particles by the total number of particles is defined as the average circularity.

[Formula 1]

[Formula 2]

  Note that “FPIA-2100”, which is a measuring apparatus used in the present invention, first calculates the circularity of each particle. After the calculation, in calculating the average circularity, the particles are divided into divided ranges obtained by dividing the circularity of 0.400 to 1.000 at predetermined intervals according to the obtained circularity, and the center value and frequency of the dividing points are used. A calculation method for calculating the average circularity is used. Specifically, the circularity is 0.400 to 1.000 at intervals of 0.010, 0.400 or more and less than 0.410, 0.410 or more and less than 0.420 ... 0.990 or more and 1.000. It is divided into 61 divided ranges such as less than 1.000.

  There is very little error between each value of the average circularity calculated by this calculation method and each value of the average circularity calculated by the calculation formula that directly uses the circularity of each particle described above. It can be ignored. Therefore, in the present invention, the concept of the calculation formula that directly uses the circularity of each particle described above is used for the reason of handling data such as shortening of the calculation time and simplification of the calculation formula, and a partial change is made. Such a calculation method is used.

  The toner used in the image forming apparatus of the present invention preferably has a high circularity. Specifically, if it is 0.960 or more, more preferably 0.970 or more, the transfer performance is high, and an image with little fog is easily obtained.

  Furthermore, the toner used in the present invention preferably has a weight average particle diameter of 4 to 9 μm, and can obtain a high-definition image. The weight average particle diameter in the present invention is measured as follows.

  As a measuring device, for example, Coulter Counter TA-II, Coulter II (manufactured by Coulter) or Coulter Multisizer III (manufactured by Beckman Coulter) is used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 ml of the electrolytic aqueous solution, and 5 mg of a measurement sample (toner and toner particles) is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 minute with an ultrasonic disperser, and the volume and number of toner particles are measured for each channel by using the 100 μm aperture as the aperture by the above-described measuring apparatus. Volume distribution and number distribution are calculated. A weight-average toner weight average particle diameter D4 (μm) obtained from the volume distribution of the toner particles is obtained.

<Measurement method of Martens hardness>
The Martens hardness HM is measured using FISCHERSCOPE HM2000S manufactured by Fischer Instruments.

  The Martens hardness HM is measured with a test load applied. The Martens hardness HM is obtained from the value obtained by increasing the test weight and, if possible, the weight / indentation depth after reaching a predetermined weight. Specifically:

  The Martens hardness HM is defined as the quotient of the applied test force (F) and the surface area A (h) of the indentation, and the indentation surface area A (h) is calculated from the indenter indentation depth (h). A Vickers indenter is used as the indenter.

[Formula 3]
HM = F / As (h) = F / (26.43 × h ₂ )

The apparatus is set so that the maximum indentation depth h _{2 is} 0.002 mm, the maximum test load Fmax is 0.2 mN, and the test time is 30 s.

  From the obtained test load when the indentation depth is 1 μm, the Martens hardness HM in the present invention can be obtained from the above formula 3. In the present invention, the Martens hardness of the toner surface obtained from the above formula 3 is HMD, and the Martens hardness of the charging roller surface is HMR.

  More specifically, the Martens hardness HMD on the toner surface and the Martens hardness HMR on the surface of the charging roller in the present invention are measured as follows.

a) According to ISO 14577-1 b) Indenter material and shape: Vickers indenter, face angle 136, Young's modulus 1140, Poisson's ratio 0.07, HV = 0.0945 × HIT
c) Method used to determine the zero point: Glass REFERENCE
d) Temperature / humidity during the test: 23 ° C./50% RH
e) Analysis method HM2000S WIN-HCU software

  In the measurement of the Martens hardness HMD of the toner surface, the toner is developed on the image carrier. At this time, measurement is performed for each toner particle on the image carrier while confirming with a microscope. The measurement sample was based on the average value of 50 arbitrarily selected toner particles.

  On the other hand, the Martens hardness HMD on the surface of the charging roller was measured by arbitrarily measuring 50 points in an area corresponding to the image forming portion of the charging roller and taking an average value.

In the present invention, the Martens hardness is calculated from the load when the indentation depth reaches 0.001 mm. The unit of Martens hardness in the present invention is N / mm ² . It is a feature of the present invention that attention is paid to the hardness of this pole surface.

  For example, if the indentation depth is too large, for example, in the vicinity of 7 μm, a minute difference in hardness of the surface layer of the charging roller cannot be distinguished, and a value that does not differ is measured. For this reason, it becomes impossible to determine the toner breakage in this embodiment. In addition, in the toner, there is a possibility that the surface of the particle size is crushed and cannot be measured. Therefore, the indentation depth is preferably measured at about 0.001 mm.

  Similarly, since the MD1 hardness is too deep, the difference in hardness between the extreme surfaces of the charging roller cannot be measured, and the problem of the present invention cannot be solved. In the present invention, MD1 hardness is a measurement method commonly used by those skilled in the art. Specifically, it is the hardness measured using an Asker micro rubber hardness meter MD-1 type-A (trade name) manufactured by Kobunshi Keiki Co., Ltd. In the present invention, the charging member placed in an environment of normal temperature and normal humidity (23 ° C./50% RH) for 12 hours or more is a value measured with the hardness meter in a 10 N peak hold mode.

  In the present invention, the relationship between the contact position between the photosensitive drum 1 and the charging roller 2, the contact position between the photosensitive drum 1 and the developing sleeve 31, and the contact position between the developing sleeve 31 and the developing blade 33 is illustrated. The positional relationship shown in FIG. That is, the relationship between these contact positions is the contact position between the photosensitive drum 1 and the charging roller 2, the contact position between the photosensitive drum 1 and the developing sleeve 31, and the developing sleeve 31 and the development from the upper side in the direction of gravity. This is the order of the contact position with the blade 33.

  Further, the present invention is not limited to an image forming apparatus in which the image carrier, the charging member, and the developing unit can be individually replaced. For example, the present invention is also effective when applied to a process cartridge that is detachable from the image forming apparatus. As the process cartridge, at least the image carrier, the charging member, and the developing unit are integrally held and detachable from the image forming apparatus, so that the process cartridge can be easily replaced by the user. Further, when the Martens hardness of the surface of the charging member is HMR and the Martens hardness of the developer surface is HMD, the relationship of HMD> HMR is satisfied, which is the same as when applied to an image forming apparatus. In addition, an image having stable quality over a long period of time can be obtained.

[Example 1]
Using the image forming apparatus described above, evaluation was performed using [Charging Roller Production Example 1] as a charging roller and [Toner Production Example 1] as a toner.

  The evaluation environment was a temperature of 23 ° C., a humidity of 50%, a 100 g developer was filled in the toner, the printing rate was 1.5%, and 3000 sheets of A4 paper were printed for durability evaluation.

  The evaluation items are observation of image quality, fog on the drum, and toner shape on the developing sleeve at that time. The toner shape is observed with an electron microscope. The effect is measured by the ratio of the number of toner particles recognized as having a different shape to the total number of toner particles.

  The durability results are as listed in Tables 1 and 2 below. When the Martens hardness of the charging roller is 3 and the Martens hardness of the toner is 11, the toner on the developing sleeve is almost free of cracks, the fog on the photosensitive drum is 4%, and the image quality is good.

[Table 1]

[Table 2]

  An example of the weighted indentation depth curve when the Martens hardness of the charging roller and toner used in this example is measured is shown in FIG. In FIG. 2, the Martens hardness of the charging roller is indicated by a solid line, and the Martens hardness of the toner is indicated by a dotted line.

In addition to the durability evaluation, accelerated evaluation is also performed for simply confirming toner cracking and deformation. In the acceleration evaluation method, toner is evaluated using the image forming apparatus described in the embodiments. First, the toner to be evaluated is developed with a solid black (m / s = about 8 g / m ² ) of 25 mm in the circumferential direction of the photosensitive drum, and the toner is placed on the photosensitive drum. At this time, a charging roller to be evaluated is used. Thereafter, the developing device is removed, and idling is performed for 12 minutes. Then, after 12 minutes, the toner adhering to the charging roller is observed. The shape of the toner is observed with an electron microscope, and the effect is measured by the ratio of the number of toner particles recognized as having a different shape with respect to the total number of toner particles. As an example, in the configuration of Example 1 in Table 1 and the configuration of Comparative Example 1, acceleration evaluation was performed and images taken with an electron microscope are shown in FIGS. 4 (a) and 4 (b). In the configuration of Example 1, as shown in FIG. 4A, it was confirmed that most of the toner maintained a spherical state. Further, with respect to the configuration of Comparative Example 1, as shown in FIG. 4B, toner cracking and deformation could be confirmed.

[Example 2]
Durability evaluation was performed in the same manner as in Example 1 using [Charging Roller Production Example 3] as the charging roller and [Toner Production Example 4] as the toner. The durability results are as listed in Tables 1 and 2. In the configuration in which the Martens hardness of the charging roller is 13.4 and the Martens hardness of the toner is 19.1, the toner on the developing sleeve is hardly cracked, the fog on the photosensitive drum is 4%, and the image quality is good. Met.

Example 3
Durability evaluation was performed in the same manner as in Example 1 using [Charging Roller Production Example 2] as the charging roller and [Toner Production Example 2] as the toner. The durability results are as listed in Tables 1 and 2. In the configuration where the Martens hardness of the charging roller is 2.5 and the Martens hardness of the toner is 5, the toner on the developing sleeve is hardly cracked, the fog on the photosensitive drum is 5%, and the image quality is good. It was.

[Comparative Example 1]
Durability evaluation was performed in the same manner as in Example 1 using [Charging Roller Production Example 3] as the charging roller and [Toner Production Example 1] as the toner. The durability results are as listed in Tables 1 and 2. In the configuration where the Martens hardness of the charging roller is 13.4 and the Martens hardness of the toner is 11, the toner on the developing sleeve is about half of the cracks, the fog on the photosensitive drum is 24%, and the image quality is charged. It was bad.

[Comparative Example 2]
Durability evaluation was performed in the same manner as in Example 1 using [Charging Roller Production Example 1] as the charging roller and [Toner Production Example 3] as the toner. The durability results are as listed in Tables 1 and 2. In the configuration where the Martens hardness of the charging roller is 3 and the Martens hardness of the toner is 2.1, the toner on the developing sleeve is about half of the cracks, the fog on the photosensitive drum is 20%, and the image quality is charged. It was bad.

<Effect of the present invention>
Using Example 1 in which the Martens hardness HMR on the surface of the charging roller and the Martens hardness HMD on the toner surface satisfy the relationship of HMD> HMR, and a comparative example that does not satisfy the above-described relationship, the toner cracking and fogging are performed. The image quality was evaluated. Comparative Example 1 prepared as a comparative sample of Example 1 has a configuration in which the hardness of only the charging roller of the configuration of Example 1 is increased, and Comparative Example 2 has a configuration in which the hardness of only the toner of the configuration of Example 1 is decreased.

  In Examples 2 and 3, the evaluation is performed by changing the hardness to the upper side and the lower side within the range where the condition of HMD> HMR is satisfied.

  As described above, in Example 1, even when the number of sheets is 3000, there is almost no toner cracking and the amount of fog toner is small, so that stable image quality can be maintained without fouling the charging roller. On the other hand, in Comparative Examples 1 and 2, the fogging deteriorated at 3000 sheets, and the amount of toner adhering to the charging roller increased, resulting in charging failure. Further, about half of the toner on the developing sleeve was observed. This is because in the configurations of Comparative Examples 1 and 2, the toner is broken between the charging roller and the photosensitive member, and the broken toner is collected in the developing container. Therefore, as for the toner in the developing container, the broken toner increases with durability, and the ratio of the broken toner to the toner on the developing sleeve also increases. Therefore, the amount of toner that is not sufficiently charged with toner increases, and the amount of toner that covers the photoreceptor increases. Since the covered toner is not easily charged to the negative polarity, it is not transferred, but adheres to the charging roller and causes a charging failure.

  Further, as in Examples 2 and 3, even when the hardness was changed up and down, when the charging roller and toner satisfying the condition of HMD> HMR were used, the image quality was stable in the durability of 3000 sheets.

  As described above, a material having a Martens hardness HMD on the surface of the charging roller smaller than the Martens hardness HMD on the surface of the toner is used. As a result, the toner can be prevented from cracking and deforming between the charging roller and the photosensitive drum, the fog can be kept good, and a good image can be obtained through durability.

  Martens hardness is the relationship of hardness in a small surface area in nanometers. As for the toner, since the surface strength of each particle is measured, one side of the surface region is preferably 700 nm or less (7 μm or less). In the Martens hardness, in order to measure the indentation strength, the hardness is from the surface layer to 700 nm or less. If the toner is small, the range is even smaller.

  As described above, in this embodiment, the magnetic spherical toner prepared by the suspension polymerization method is used, but the toner that can be used is not limited to this. In addition, the present invention can be similarly applied to a toner manufactured by a known manufacturing method, for example, a toner manufactured by a pulverization method, a method of agglomerating emulsified particles, or the like. Furthermore, the present invention can be applied not only to magnetic toner but also to non-magnetic toner.

  In the present embodiment, an example of the one-component development method is shown, but it goes without saying that other known development methods such as a so-called two-component development method can be adopted.

  As described above, according to the present invention, even if the developer remaining on the image carrier after transfer passes between the image carrier and the charging member, the charging member is softer than the developer. Therefore, it is easily deformed and the burden on the developer is eased. For this reason, it becomes possible to suppress the cracking and deformation of the developer.

  Therefore, in a so-called cleaner-less system in which the developer remaining on the image carrier after transfer is collected by a developing member, it is possible to suppress image adverse effects such as fogging and obtain an image with stable quality over a long period of time.

Example 4
In the above example, the average value of the charging roller was used for comparison with the toner. However, the hardness actually varies, and the hardness of the charging roller also has a distribution. Therefore, even if the average value of the charging roller is softer than the average value of the toner, depending on the distribution of the charging roller, there are many harder portions than the toner, and the toner is likely to be cracked and deformed.

  Therefore, in Example 4, considering the variation in hardness of the charging roller, the Martens hardness HMD of the surface of the toner as the developer is higher than the value of the Martens hardness HMR + 3σ of the surface of the charging roller as the charging member. Set (HMD> HMR + 3σ). As a result, it is possible to suppress toner cracking, deformation, and the like over a long period of time, reduce fogging deterioration, and stabilize image quality.

  In Example 4, the Martens hardness of the charging roller is managed by distribution. In comparison, Comparative Example 3 that satisfies only HMD> HMR is compared with Example 4 that satisfies the relationship of both HMD> HMR and HMD> HMR + 3σ (see Table 3 and FIG. 5).

[Table 3]

  Evaluation is performed using the same image forming apparatus as in the first embodiment. Table 3 shows the configuration of the charging roller and toner used. The distribution of Martens hardness is shown in FIG.

  In Example 4, the evaluation is performed using [Charging Roller Production Example 4] as the charging roller and [Toner Production Example 5] as the toner (see Table 3). [Toner Production Example 5] uses a toner whose Martens hardness average value of the toner is harder than the value of + 3σ of the charging roller hardness distribution of [Charging Roller Production Example 4]. The toner production example 5 is prototyped so that the toner aspect ratio is higher than that of the toner production example 6. Since the irregularly shaped toner has a soft hardness, a toner having a high aspect ratio results in a toner having a high average hardness value. The aspect ratio mentioned here refers to the ratio of the long side to the short side of the toner particles.

  In Comparative Example 3, evaluation was performed using [Charging Roller Production Example 4] as the charging roller and [Toner Production Example 6] as the toner. [Toner Production Example 6] uses a toner whose Martens hardness average value of the toner is softer than the value of + 3σ of the charging roller hardness distribution of [Charging Roller Production Example 4].

  Note that the Martens hardness HMD of the toner used in Comparative Example 3 (8 in Table 3) and the Martens hardness HMD of the toner used in Example 4 (11 in Table 3) are both charging rollers [Charging Roller Production Example 4]. Toner having a Martens hardness HMR (6 in Table 3) is used.

Here, it is assumed that a sample composed of n pieces of data x ₁ , x ₂ ,..., X _n is extracted as the Martens hardness HMD of the toner. At this time, the standard average is defined by the following formula 4. Here, the Martens hardness HMD (average value) of the toner is calculated using the following equation 4 using 50 points of data.

[Formula 4]

However, since it is not possible to know how the above-mentioned data is distributed only by the average value, the degree of dispersion indicating the range of variation of this data is used. In order to show the degree of dispersion of this data, the square of the difference (deviation) from the average value of the data is averaged, and the standard deviation s (σ) taken as the positive square root is shown to indicate this in the same dimension as the variable. Use. The value before taking the positive square root (the square of the standard deviation) is called the variance s ² and is defined by the following formula 5. Here, the standard deviation σ of the Martens hardness HMR of the charging roller is calculated using Equation 5 below.

[Formula 5]

  Here, 70% of the data of 50 points is distributed within the range of the average value ± standard deviation σ of the Martens hardness of the charging roller, 96% is distributed within the range of ± 2σ, and 100 within the range of ± 3σ. % Was distributed. In this embodiment, the average value of the Martens hardness of the charging roller up to + 3σ is a target to be compared with the Martens hardness of the toner (HMD> HMR + 3σ). As a result, even if the Martens hardness of the charging roller varies, it is possible to reduce toner breakage, chipping, etc., and to extend the service life.

[Toner Production Example 5]
The toner of the present invention is a toner obtained by using a toner particle production method including the following steps. The step comprises forming a particle of a polymerizable monomer composition containing a polymerizable monomer, a colorant and a polyester resin in a first aqueous medium containing a dispersion stabilizer A, the polymerizable property This is a polymerization step in which the polymerizable monomer contained in the particles of the monomer composition is polymerized to obtain toner particles. In the toner, the acid value of the polyester resin is 0.3 mgKOH / g or more and 1.5 mgKOH / g or less. The toner contains 5.0% by mass or more and 20% by mass or less of the polyester resin based on the polymerizable monomer composition, and the first aqueous medium contains the polymerizable monomer. It contains 1.5% by weight or more and 5.9% by weight or less sodium chloride based on the composition.

  The method for producing toner particles of the present invention is such that the acid value of the polyester resin is low, and the content is 5.0% by mass or more and 20% by mass or less based on the polymerizable monomer composition. Is important for obtaining high aspect ratio toner particles. The reason is not clear, but by containing a large amount of low acid value polyester resin, the dispersibility of the colorant in the polymerizable monomer composition in the granulation step and the polymerization step is improved, and the polymerizable single amount It is considered that the particles of the body composition are stabilized in the aqueous medium. Thereby, the coalescence of the particles is suppressed, and it is considered that toner particles having a high aspect ratio can be obtained.

  On the other hand, when a high acid value polyester resin is contained in a large amount, the particle size distribution becomes broad. Conventionally, it has been considered that the resin contained in the polymerizable monomer has a high acid value, so that it becomes easy to be oriented at the interface between the aqueous phase and the oil phase, and the particles are stabilized. However, if it is added too much, the dispersibility of the colorant in the polymerizable monomer composition may be lowered and the stability of the droplets may be impaired.

  Therefore, the content of the low acid value polyester resin is preferably 5.0% by mass or more and 20% by mass or less based on the polymerizable monomer composition. When the content is less than 5.0% by mass, the aspect ratio of the toner particles becomes insufficient. Even when the content exceeds 20% by mass, the aspect ratio of the toner particles cannot be more effective, and the viscosity of the polymerizable monomer composition increases. Therefore, since manufacturing stability may fall, it is not preferable.

  The toner particle production method of the present invention includes the control of the content of the low acid value polyester, and 1.5% by mass or more and 5.9% by mass or less based on the polymerizable monomer composition in the aqueous medium. It is important to contain sodium chloride in order to suppress fine particles. By containing a large amount of sodium chloride in the aqueous medium, it is possible to suppress the monomer of the polymerizable monomer from dissolving into the aqueous medium from the particles of the polymerizable monomer composition due to the salting-out effect. If the monomer of the polymerizable monomer is dissolved in the aqueous medium, a dispersion stabilizer adheres to the monomer and fine particles such as so-called emulsified particles are generated. Moreover, the particle | grains of the polymerizable monomer composition which have a desired particle size may be adhere | attached starting from an emulsified particle | grain, and a coalesced particle may be generated.

  Therefore, the content of sodium chloride is preferably 1.5% by mass or more and 5.9% by mass or less based on the polymerizable monomer composition. Conventional dispersion stabilizers produce by-product salts in aqueous media. However, the content of the by-product salt is small for the salting out effect. On the other hand, when the amount of the dispersion stabilizer added is large, toner particles having a desired particle diameter cannot be obtained, and it is preferable to add sodium chloride. If the content of the by-product salt and the added sodium chloride is less than 1.5% by mass, the suppression of fine particles becomes insufficient. Even if the content exceeds 5.9% by mass, the effect of suppressing the fine particles cannot be obtained any more, and the content of sodium chloride remaining in the toner particles increases. Therefore, the chargeability of the toner may be deteriorated, which is not preferable.

  The present invention further includes a step of mixing the particles of the polymerizable monomer composition obtained in the granulation step and a second aqueous medium, and the second aqueous medium is the dispersion stabilizer A. The dispersion stabilizer B is preferably contained in an amount of 5.0% by mass or more and 40% by mass or less based on the above. By containing the above-mentioned content of the dispersion stabilizer B in the second aqueous medium, it becomes possible to compensate for the dispersion stabilizer that is insufficient during granulation and to obtain toner particles having a higher aspect ratio. However, if the content of the dispersion stabilizer B is less than 5.0% by mass based on the dispersion stabilizer A, the effect of further improving the aspect ratio is insufficient. On the other hand, if it exceeds 40% by mass, the excessive dispersion stabilizer B tends to adhere to the volatile monomer of the polymerizable monomer during polymerization and increase the fine particles, which is not preferable.

  Moreover, as for this invention, it is preferable to adjust content of this sodium chloride of this 1st aqueous medium by adding sodium chloride to this 1st aqueous medium as mentioned above.

  In the present invention, the dispersion stabilizer A is preferably prepared by mixing an aqueous calcium chloride solution and an aqueous sodium phosphate solution. From calcium chloride and calcium phosphate, hydroxyapatite and sodium chloride as a by-product salt are produced as shown in the following formula 6. Hydroxyapatite is a preferred dispersion stabilizer for stabilizing the particles of the polymerizable monomer composition. Moreover, since sodium chloride is produced as a by-product salt, it is preferably used in the present invention in order to express a salting-out effect for suppressing fine particles.

[Formula 6]
6Na3Po4 + 10CaCl2 + 2H2O → [Ca3 (PO4) 2] 3Ca (OH) 2 + 18NaCl + 2HCl

  Hereinafter, a material configuration and a manufacturing method for carrying out the present invention will be described in detail.

  In the present invention, it is produced by a suspension polymerization method in which a polymerizable monomer composition is granulated in an aqueous medium to form particles of the polymerizable monomer composition.

  As the polymerizable monomer, a vinyl monomer capable of radical polymerization is used. As the vinyl monomer, a monofunctional monomer or a polyfunctional monomer can be used.

  Monofunctional monomers include styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene; methyl Acrylic polymerizable monomers such as acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, dibutyl Methacrylic polymerizable monomers such as phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate and vinyl propionate; vinyl methyl ether; Sulfonyl ethyl ether, vinyl ether such as vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone, and vinyl ketones such as vinyl isopropyl ketone.

  Among the above, the polymerizable monomer preferably contains styrene or a styrene derivative.

  Examples of the polyfunctional monomer include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinyl ether and the like.

  You may use the above-mentioned monofunctional monomer individually or in combination of 2 or more types, or combining the above-mentioned monofunctional monomer and polyfunctional monomer. Polyfunctional monomers can also be used as crosslinking agents.

  As the polymerization initiator used in the present invention, an oil-soluble initiator and / or a water-soluble initiator is used. Preferably, the half-life at the reaction temperature during the polymerization reaction is 0.5 to 30 hours. Further, when the polymerization reaction is carried out at an addition amount of 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer, a polymer having a maximum value between 10,000 and 100,000 is usually obtained. It is preferable because toner particles having excellent strength and melting characteristics can be obtained.

  As polymerization initiators, the following 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbohydrate) were used. Nitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisisobutyronitrile; benzoyl peroxide, t-butylperoxy 2- Ethyl hexanoate, t-butyl peroxypivalate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4- Peroxides such as dichlorobenzoyl peroxide and lauroyl peroxide Examples thereof include initiators.

  In the present invention, in order to control the degree of polymerization of the polymerizable monomer, a known chain transfer agent, polymerization inhibitor or the like can be further added and used.

  In the present invention, the polymerizable monomer composition contains a polyester resin. Examples of the polyester resin used in the present invention include the following.

  Examples of the divalent acid component include the following dicarboxylic acids or derivatives thereof. Benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or their anhydrides or lower alkyl esters thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or their anhydrides or lower thereof Alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydrides thereof or lower alkyl esters thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid Or its anhydride or its lower alkyl ester.

  The following are mentioned as a bivalent alcohol component. Ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, formula (1) ) Bisphenol and its derivatives:

[Chemical formula 1]

  In the above formula 1, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.

  The polyester resin that can be used in the present invention may be contained as the following constituent components in addition to the above-described divalent carboxylic acid compound and divalent alcohol compound. The constituent components are a monovalent carboxylic acid compound, a monovalent alcohol compound, a trivalent or higher carboxylic acid compound, and a trivalent or higher alcohol compound.

  Examples of the monovalent carboxylic acid compound include aromatic carboxylic acids having 30 or less carbon atoms such as benzoic acid and p-methylbenzoic acid, and aliphatic carboxylic acids having 30 or less carbon atoms such as stearic acid and behenic acid. .

  Examples of monovalent alcohol compounds include aromatic alcohols having 30 or less carbon atoms such as benzyl alcohol, and aliphatic alcohols having 30 or less carbon atoms such as lauryl alcohol, cetyl alcohol, stearyl alcohol, and behenyl alcohol. It is done.

  Although it does not restrict | limit especially as a trivalent or more carboxylic acid compound, A trimellitic acid, trimellitic anhydride, pyromellitic acid, etc. are mentioned.

  Examples of the trivalent or higher alcohol compound include trimethylolpropane, pentaerythritol, and glycerin.

  The production method of the polyester resin that can be used in the present invention is not particularly limited, and a known method can be used.

  In the present invention, the polymerizable monomer composition may contain a wax as a release agent.

  The wax is preferably a hydrocarbon wax such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, or paraffin wax from the viewpoint of high releasability. If necessary, two or more kinds of waxes may be used in combination.

  Specific examples of the wax include the following. Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), High Wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals) ), Sazole H1, H2, C80, C105, C77 (Schumann Sazol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 (Toyo Adre Co., Ltd.), wood wax, beeswax, rice wax, candelilla wax Carnauba wax (available from Celerica NODA).

  The added amount of the wax is preferably 1.0 to 20.0 parts by mass of wax with respect to the binder resin.

  The toner particles of the present invention may be magnetic toner particles or non-magnetic toner particles.

  When manufacturing as magnetic toner particles, it is preferable to use magnetic iron oxide as the magnetic material. As the magnetic iron oxide, iron oxides such as magnetite, maghematite, and ferrite are used. The amount of magnetic iron oxide contained in the toner is preferably 25.0 parts by mass or more and 100.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

  When producing non-magnetic toner particles, carbon black or other known pigments or dyes can be used as the colorant. Further, only one kind of pigment or dye may be used, or two or more kinds may be used in combination. The colorant contained in the toner is preferably 0.1 parts by mass or more and 60.0 parts by mass or less, more preferably 0.5 parts by mass or more and 50.0 parts by mass with respect to 100 parts by mass of the binder resin. Or less.

  In the method for producing toner particles by the suspension polymerization method, in addition to the materials described above, a known charge control agent, conductivity imparting agent, lubricant, abrasive, and the like may be added.

  In the suspension polymerization toner particles, these additives are uniformly dissolved or dispersed to form a polymerizable monomer composition. Thereafter, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer using an appropriate stirrer, and if necessary, an aromatic solvent and a polymerization initiator are added to perform a polymerization reaction. To obtain toner particles having a desired particle diameter.

  After the polymerization of the toner particles, the toner is obtained by filtering, washing and drying by a known method, and if necessary, mixing inorganic fine powder as a fluidity improver and adhering it to the surface.

  Known inorganic fine powders can be used. Preferred are silica fine particles such as titania fine particles, wet-processed silica, and dry-process silica, and inorganic fine powders obtained by surface-treating these silicas with a silane coupling agent, a titanium coupling agent, or silicone oil. The inorganic fine powder subjected to the surface treatment preferably has a degree of hydrophobicity of 30 or more and 98 or less titrated by a methanol titration test.

<Production example of magnetic body 1>
In a ferrous sulfate aqueous solution, 1.00 to 1.10 equivalent of caustic soda solution with respect to iron element, P2O5 in an amount of 0.15% by mass in terms of phosphorus element with respect to iron element, silicon with respect to iron element SiO2 in an amount of 0.50% by mass in terms of element was mixed. Thus, an aqueous solution containing ferrous hydroxide was prepared. The pH of the aqueous solution was 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.

  Subsequently, the ferrous sulfate aqueous solution was added to this slurry liquid so that it might become 0.90 to 1.20 equivalent with respect to the original alkali amount (sodium component of caustic soda). Thereafter, the slurry liquid was maintained at pH 7.6, and an oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured. Next, this water-containing sample is put into another aqueous medium without being dried, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid is adjusted to about 4.8. Then, 1.6 parts of n-hexyltrimethoxysilane coupling agent was added to 100 parts of magnetic iron oxide with stirring (the amount of magnetic iron oxide was calculated as a value obtained by subtracting the water content from the water-containing sample), and water was added. Decomposition was performed. Thereafter, the mixture was sufficiently stirred, and the dispersion was subjected to surface treatment at a pH of 8.6. The produced hydrophobic magnetic material is filtered with a filter press, washed with a large amount of water, dried at 100 ° C. for 15 minutes, and then at 90 ° C. for 30 minutes. 0.21 μm magnetic body 1 was obtained.

<Example of production of polyester resin B1>
Into a reaction vessel equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, the amount of monomer shown in Table 4 was added, and then dibutyltin was used as a catalyst in an amount of 1.5 mass with respect to 100 mass parts of the total monomer amount Part was added. Next, the temperature was quickly raised to 180 ° C. under normal pressure in a nitrogen atmosphere, and then water was distilled off while heating from 180 ° C. to 210 ° C. at a rate of 10 ° C./hour to perform polycondensation. After reaching 210 ° C., the pressure in the reaction vessel was reduced to 5 kPa or less, and polycondensation was performed under the conditions of 210 ° C. and 5 kPa or less to obtain polyester resin B1. At that time, the polymerization time was adjusted so that the softening point of the obtained polyester resin B1 was the value shown in Table 5 (125 ° C.). Table 5 shows the physical properties of the polyester resin B1.

[Table 4]

[Table 5]

  Toner particles and toner were produced by the following procedure.

(Adjustment of the first aqueous medium)
Into 342.8 parts by mass of ion-exchanged water, 3.1 parts by mass of sodium phosphate 12 hydrate was added and heated to 60 ° C. with stirring using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). did. Thereafter, an aqueous calcium chloride solution in which 1.8 parts by mass of calcium chloride dihydrate was added to 12.7 parts by mass of ion-exchanged water, and chloride in which 4.3 parts by mass of sodium chloride was added to 14.5 parts by mass of ion-exchanged water. Sodium aqueous solution was added and stirring was advanced. And the 1st aqueous medium containing the dispersion stabilizer A was obtained.

(Adjustment of polymerizable monomer composition)
Styrene 74.0 parts by mass n-butyl acrylate 26.0 parts by mass 1-6 hexanediol diacrylate 0.5 parts by mass Aluminum salicylate compound (E-101: manufactured by Orient Chemical Co., Ltd.) 0.5 parts by mass Colorant: 65.0 parts by mass of magnetic material 1 20.0 parts by mass of polyester resin B1

  The above materials were uniformly dispersed and mixed using an attritor (manufactured by Mitsui Miike Chemical Co., Ltd.), then heated to 60 ° C., and 15.0 parts by mass of paraffin wax (DSC peak temperature: 80 ° C.) was added thereto. The mixture was added and dissolved to obtain a polymerizable monomer composition.

(Adjustment of the second aqueous medium)
0.9 parts by mass of sodium phosphate dodecahydrate was added to 164.7 parts by mass of ion-exchanged water, and the mixture was heated to 60 ° C. with stirring using a paddle stirring blade. Thereafter, a calcium chloride aqueous solution in which 0.5 part by mass of calcium chloride dihydrate was added to 3.8 parts by mass of ion-exchanged water was added, and stirring was continued to obtain a second aqueous medium containing the dispersion stabilizer B.

(Granulation)
In the first aqueous medium, 7.0 parts by mass of the polymerizable monomer composition and t-butyl peroxypivalate as a polymerization initiator were charged. Then, granulation liquid containing granules of the polymerizable monomer composition is granulated with stirring at 12000 rpm for 10 minutes in a TK homomixer (Special Machine Industries Co., Ltd.) in an N2 atmosphere at 60 ° C. Got.

(Polymerization / distillation / drying / external addition)
The granulation liquid was put into the second aqueous medium and reacted at 74 ° C. for 3 hours while stirring with a paddle stirring blade. After completion of the reaction, the mixture was distilled at 98 ° C. for 3 hours, and then the suspension was cooled, washed with hydrochloric acid, filtered and dried to obtain toner particles having a weight average particle diameter of 8.0 μm.

  To 100 parts by mass of the obtained toner particles, the following materials were mixed with a Henschel mixer (FM-10 model manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain toner 1. The temperature of the Henschel mixer jacket was adjusted to 45 ° C.

-Hydrophobic silica fine particles having a number average particle size of 20 nm of primary particles surface-treated with 25% by mass of hexamethyldisilazane 0.5 parts by mass-Number average particle size of primary particles surface-treated with 15% by mass of hexamethyldisilazane 110 nm Hydrophobic silica fine particles 0.5 parts by mass

  The particle size distribution (D50 / D1) of the obtained toner was 1.10, and the aspect ratio was 0.930. The HM is 11.

  The measurement of HM is as described in Example 1.

  The physical properties described above were measured by the following methods.

<Measurement of physical properties of toner>
<Measurement method of weight average particle diameter (D4)>
The weight average particle diameter (D4) of the toner was calculated by measuring the number of effective measurement channels with 25,000 channels and analyzing the measurement data using the following. For the measurement, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube by the pore electrical resistance method is used to set measurement conditions and analyze measurement data. The attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) was used.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  In the “Standard Measurement Method (SOM) Change Screen” of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.

  In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  1. About 200 ml of the electrolytic aqueous solution is put in a glass-made 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.

  2. About 30 ml of the electrolytic solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.

  3. Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees. A predetermined amount of ion-exchanged water is placed in a water tank of an ultrasonic disperser “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikka Ki Bios) having an electrical output of 120 W. Then, about 2 ml of the contamination N is added to the water tank.

  4). 2. Is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

  5. 4. above. In the state where the electrolytic aqueous solution in the beaker is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  6). 4. The toner is dispersed in the round bottom beaker of 1. set up in the sample stand using a pipette. The aqueous electrolyte solution is dropped to adjust the measured concentration to about 5%. Measurement is performed until the number of measured particles reaches 50,000.

  7). Constant data is analyzed with the dedicated software attached to the apparatus, and each average particle size is calculated. When the graph / volume% is set in the dedicated software, the “arithmetic diameter” on the analysis / volume statistics screen is the weight average particle diameter D4 and the “50% D diameter” is D50. The number average particle diameter D1 is calculated in the same manner.

<Measurement method of aspect ratio and small particle ratio>
The circularity of the toner particles was measured with a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during calibration.

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

  For the measurement, the above-mentioned flow type particle image analyzer equipped with “LUCPLFLN” (magnification 20 ×, numerical aperture 0.40) as an objective lens is used, and particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. It was used. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 2000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis was set to 85%, the analysis particle diameter was limited to a circle equivalent diameter of 1.977 μm or more and less than 39.54 μm, and the aspect ratio and small particle ratio of toner particles were obtained.

  In measurement, automatic focus adjustment is performed using the following before starting measurement. That is, automatic focus adjustment is performed using standard latex particles (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A” manufactured by Duke Scientific) diluted with ion-exchanged water. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In this example, a flow type particle image analyzer which has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. Measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to a circle equivalent diameter of 1.977 μm or more and less than 39.54 μm.

<Measurement of Tg of Resin>
The Tg of the resin is measured in accordance with ASTM D3418-82 using a differential scanning calorimeter “Q2000” (manufactured by TA Instruments). The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, about 2 mg of a sample is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference. Measurement is performed at ° C / min. In the measurement, the temperature is once raised to 200 ° C., subsequently lowered to 30 ° C., and then the temperature is raised again. A specific heat change is obtained in the temperature range of 40 ° C. to 100 ° C. in the second temperature raising process. At this time, the point of intersection between the line of the midpoint of the baseline before and after the change in specific heat and the differential heat curve is defined as the glass transition temperature Tg of the resin.

<Measurement of softening point of resin>
The softening point of the resin is measured by using a constant load extrusion type capillary rheometer “flow characteristic evaluation device Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with the piston, the measurement sample filled in the cylinder is heated and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder, and the piston drop amount at this time A flow curve showing the relationship between temperature and temperature can be obtained.

  The “melting temperature in the 1/2 method” described in the manual attached to the “flow characteristic evaluation device Flow Tester CFT-500D” is defined as the softening point. The melting temperature in the 1/2 method is calculated as follows. First, ½ of the difference between the piston lowering amount Smax at the time when the outflow ends and the piston lowering amount Smin at the time when the outflow starts is obtained (this is X. X = (Smax−Smin) / 2). And the temperature of the flow curve when the amount of descending piston is the sum of X and Smin in the flow curve is the melting temperature in the 1/2 method.

  As a measurement sample, about 1.0 g of a sample is compression-molded at about 10 MPa for about 60 seconds using a tablet molding compressor (for example, NT-100H, manufactured by NPA System) in an environment of 25 ° C. A cylindrical shape having a diameter of about 8 mm is used.

  The measurement conditions of CFT-500D are: test mode: temperature rising method, temperature rising rate: 4 ° C./min, starting temperature: 50 ° C., ultimate temperature: 200 ° C.

<Measurement of acid value of resin>
The acid value of the resin is the number of mg of potassium hydroxide necessary to neutralize the acid contained in 1 g of the sample. The acid value of the polyester resin is measured according to JIS K 0070-1992. Specifically, it is measured according to the following procedure.

(1) Preparation of Reagent 1.0 g of phenolphthalein is dissolved in 90 ml of ethyl alcohol (95 vol%), and ion exchanged water is added to make 100 ml to obtain a phenolphthalein solution.

  7 g of special grade potassium hydroxide is dissolved in 5 ml of water, and ethyl alcohol (95 vol%) is added to make 1 l. In order not to touch carbon dioxide, etc., put in an alkali-resistant container and let stand for 3 days, then filter to obtain a potassium hydroxide solution. The obtained potassium hydroxide solution is stored in an alkali-resistant container. The factor of the potassium hydroxide solution was as follows: 25 ml of 0.1 mol / l hydrochloric acid was placed in an Erlenmeyer flask, a few drops of the phenolphthalein solution were added, titrated with the potassium hydroxide solution, and the hydroxide required for neutralization. Determined from the amount of potassium solution. As the 0.1 mol / l hydrochloric acid, one prepared according to JIS K 8001-1998 is used.

(2) Operation (A) Main test 2.0 g of the pulverized polyester resin sample is precisely weighed into a 200 ml Erlenmeyer flask, and 100 ml of a mixed solution of toluene / ethanol (2: 1) is added and dissolved over 5 hours. Subsequently, several drops of the phenolphthalein solution is added as an indicator, and titration is performed using the potassium hydroxide solution. The end point of titration is when the light red color of the indicator lasts for about 30 seconds.

(B) Blank test Titration is performed in the same manner as above except that no sample is used (that is, only a mixed solution of toluene / ethanol (2: 1) is used).

(3) The acid value is calculated by substituting the obtained result into the following formula 7.

[Formula 7]
A = [(C−B) × f × 5.61] / S

  Here, A: acid value (mgKOH / g), B: addition amount (ml) of a potassium hydroxide solution in a blank test, C: addition amount (ml) of a potassium hydroxide solution in this test, f: potassium hydroxide Solution factor, S: sample (g).

[Toner Production Example 6]
The toner of the present invention may be a toner produced by a known pulverization method and obtained by using a known surface treatment method such as thermal spheronization treatment, or a toner produced by a known polymerization method. Also good.

  In order to achieve the aspect ratio of the toner of the present invention, the suspension polymerization method described above is preferably used.

Styrene acrylic copolymer 100 parts by mass (mass ratio of styrene to n-butyl acrylate is 74.0: 26.0, main peak molecular weight Mp is 10,000)
・ 90 parts by mass of magnetic substance 1 ・ Aluminum salicylate compound (E-101: manufactured by Orient Chemical Co., Ltd.) 0.5 parts by mass ・ 5 parts by mass of paraffin wax (peak temperature of maximum endothermic peak: 80 ° C.)

  The mixture was premixed with a Henschel mixer, melt-kneaded with a biaxial extruder heated to 150 ° C., and the cooled kneaded product was coarsely pulverized with a hammer mill to obtain a coarsely pulverized toner product. The obtained coarsely pulverized product was coated with a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces (plating thickness 150 μm, surface hardness HV1050)). And then mechanically pulverized (pulverized). The finely pulverized product obtained was classified and removed simultaneously with a multi-division classifier (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect.

Subsequently, a thermal spheronization treatment was performed. The thermal spheronization treatment was performed using a surfing system (manufactured by Nippon Pneumatic Co., Ltd.). The operating conditions of the hot spheronizer are: feed amount = 5 kg / hr, hot air temperature C = 260 ° C., hot air flow rate = 6 m ³ / min, cold air temperature E = 5 ° C., cold air flow rate = 4 m ³ / min, cold air absolute moisture content = 3 g / m ³ , blower air flow = 20 m ³ / min, injection air flow rate = 1 m ³ / min, diffusion air = 0.3 m ³ / min.

  Toner particles were obtained by the surface treatment under the above conditions. The weight average particle diameter (D4) of the toner particles was 8.0 μm. To 100 parts by mass of the obtained toner particles, the following materials were mixed with a Henschel mixer (FM-10 model manufactured by Mitsui Miike Chemical Co., Ltd.) to obtain toner 2. The temperature of the Henschel mixer jacket was adjusted to 45 ° C.

-Hydrophobic silica fine particles having a number average particle size of 20 nm of primary particles surface-treated with 25% by mass of hexamethyldisilazane 0.5 parts by mass-Number average particle size of primary particles surface-treated with 15% by mass of hexamethyldisilazane 110 nm Hydrophobic silica fine particles 0.5 parts by mass

  The toner obtained had a particle size distribution (D50 / D1) of 1.25, an aspect ratio of 0.900, and a small particle ratio of 8.8%. The HM is 8.

  The method for measuring physical properties is as described in [Toner Production Example 5]. Further, the measurement of HM is as described in Example 1.

[Charging roller production example 4]
<1. Adjustment of unvulcanized rubber composition>
The types and amounts of materials shown in Table 6 below were mixed with a pressure kneader to obtain an A-kneaded rubber composition. Furthermore, 183.0 parts by mass of the A-kneaded rubber composition and each kind and amount of materials shown in Table 7 below were mixed with an open roll to prepare an unvulcanized rubber composition.

[Table 6]

[Table 7]

<2. Production of conductive elastic roller>
A round bar having a total length of 252 mm and an outer diameter of 6 mm was prepared by subjecting the surface of free-cutting steel to electroless nickel plating. Next, an adhesive was applied over the entire circumference in a range of 230 mm excluding 11 mm at both ends of the round bar. The adhesive used was a conductive hot melt type. A roll coater was used for coating. In this example, a round bar coated with the adhesive was used as a conductive shaft core.

  Next, a crosshead extruder having a conductive shaft core supply mechanism and an unvulcanized rubber roller discharge mechanism is prepared, and a die having an inner diameter of 12.5 mm is attached to the crosshead. The conveyance speed of the conductive shaft core was adjusted to 60 mm / sec. Under these conditions, the unvulcanized rubber composition was supplied from the extruder, and the uncured rubber composition was coated as an elastic layer on the conductive shaft core body in the crosshead to obtain an unvulcanized rubber roller. . Next, the unvulcanized rubber roller was put in a hot air vulcanization furnace at 170 ° C. and heated for 60 minutes to obtain an unpolished conductive elastic roller. Then, the edge part of the elastic layer was excised and removed. Finally, the surface of the elastic layer was polished with a rotating grindstone. As a result, a conductive elastic roller having a central diameter of 8.5 mm was obtained. The crown amount of this roller (the difference in outer diameter at a position 90 mm away from the central portion and the central portion) was 110 μm.

<3. Preparation of coating liquid 1>
The binder resin coating solution for forming the conductive layer according to the present invention was prepared by the following method.

  Under a nitrogen atmosphere, 100 parts by mass of polyester polyol (trade name: manufactured by Kuraray Co., Ltd.) was gradually added dropwise to 27 parts by mass of polymer MDI (trade name: Millionate MR200, manufactured by Nippon Polyurethane Industry Co., Ltd.) in a reaction vessel. At this time, the above-mentioned dropping was performed while maintaining the temperature in the reaction vessel at 65 ° C. After completion of the dropping, the reaction was carried out at a temperature of 65 ° C. for 2 hours. The resulting reaction mixture was cooled to room temperature to obtain an isocyanate group-terminated prepolymer 1 having an isocyanate group content of 4.3%.

  Similarly, 51.5 parts by mass of the isocyanate group-terminated prepolymer 1, 41.52 parts by mass of polyester polyol (trade name: P2010 Kuraray Co., Ltd.) and carbon black (MA230: manufactured by Mitsubishi Chemical Corporation) are methyl ethyl ketone (MEK). Dissolved in. And it adjusted so that solid content might be 27 weight%. The mixed liquid 1 was produced as described above. In a glass bottle having an inner volume of 450 mL, 270 g of the mixed solution 1 and 200 g of glass beads having an average particle diameter of 0.8 mm were placed and dispersed for 12 hours using a paint shaker disperser. After the dispersion, 30 parts by mass of urethane particles having an average particle diameter of 7.0 μm (Dymic Beads UCN-5070D: manufactured by Dainichi Seika Kogyo Co., Ltd.) was added. Then, after further dispersing for 15 minutes and removing the glass beads, a surface layer coating solution 1 was obtained.

<4. Coating of conductive roller>
The conductive elastic roller prepared in 2 above was dipped once in the coating solution 1 prepared by the above method 3, and then air-dried at 23 ° C. for 30 minutes. Next, the conductive elastic roller is dried in a hot air circulating dryer set at 80 ° C. for 1 hour, and further dried in a hot air circulating dryer set at 160 ° C. for 1 hour, on the outer peripheral surface of the conductive elastic roller. A conductive layer was formed. The dipping coating dipping time is 9 seconds, the dipping coating lifting speed is adjusted so that the initial speed is 20 mm / sec and the final speed is 2 mm / sec, and the time between 20 mm / sec and 2 mm / sec is linear with respect to time. The speed was changed.

  The charging roller was manufactured by the above method. As shown in Table 3, HM has an average of 50 points of 6. Further, the distribution of Martens hardness of the charging roller at that time is as shown in FIG.

<Durability results>
The evaluation environment was a temperature of 23 ° C., a humidity of 50%, a 100 g developer was filled in a toner, the printing rate was 1.5%, and 5000 sheets of A4 paper were printed for durability evaluation.

  About comparison of the results, the durability of 3000 sheets and 5000 sheets was evaluated, and as shown in Table 8.

[Table 8]

  In Example 4, the durability was 3000 sheets and 5000 sheets, and the fogging was not deteriorated. On the other hand, in Comparative Example 3, the fog was 5% when 3000 sheets were used, but deteriorated to 12% when 5000 sheets were used.

  Therefore, not only the average value of the Martens hardness of the charging roller is softened but also the average value of the Martens hardness of the toner is grasped, and the distribution of the Martens hardness of the charging roller is grasped, and + 3σ of the distribution is represented as the Martens hardness of the toner. Softer than the average value. As a result, if the charging roller of this embodiment is used, toner breakage, chipping, and the like can be reduced, and the life can be extended.

[Other Examples]
The present invention may be any configuration as long as the Martens hardness on the surface of the charging member is smaller than the Martens hardness on the surface of the developer so that the deformation of the developer can be reduced. Although the cleaner-less configuration has been described above, the cleaner-less configuration is not necessary as long as it satisfies the Martens hardness relationship.

  Further, various detachable configurations can be applied to the image forming apparatus. For example, as shown in FIG. 6, a drum cartridge having a charging member and an image carrier and a developer cartridge having a developer carrier may be configured to be detachable from the image forming apparatus.

  In addition, a toner cartridge that is a developer cartridge that contains a developer separately from the developer cartridge may be configured to be detachable from the developer cartridge. As another configuration, the toner cartridge may be detachable from the image forming apparatus main body. Of course, a process cartridge including an image carrier, a charging member, and a developing member may be detachable from the main body of the image forming apparatus.

HM, HMD, HMR ... Martens hardness L ... Laser light P ... Transfer material a ... Development nip part b ... Transfer nip part c ... Charging nip part d ... Laser irradiation position t ... Toner 1 ... Photoconductor drum 2 ... Charging roller 3 ... Developer 4 ... Laser beam scanner 5 ... Transfer roller 6 ... Fixing device 31 ... Developing sleeve 32 ... Magnet roller 33 ... Developing blade 34 ... Agitating member 70 ... Cassette 71 ... Feeding roller

Claims (23)

An image bearing member; a charging member that contacts the image bearing member to charge the image bearing member; and a developing member that contacts the image bearing member and supplies developer. In the image forming apparatus for collecting the developer remaining on the body by the developing member,
When the Martens hardness of the surface of the charging member is HMR and the Martens hardness of the surface of the developer is HMD,
HMD> HMR
An image forming apparatus characterized by the following relationship:   The image forming apparatus according to claim 1, wherein the surface of the charging member has a Martens hardness HMR of 0.5 or more and 19 or less.   The image forming apparatus according to claim 1, wherein the surface of the charging member has a Martens hardness HMR of 1 or more and 10 or less.   The image forming apparatus according to claim 1, wherein a Martens hardness HMD of the surface of the developer is 2 or more and 50 or less.   The image forming apparatus according to claim 1, wherein a Martens hardness HMD of the surface of the developer is 2.5 or more and 20 or less.   6. The image forming apparatus according to claim 1, wherein an arithmetic average roughness Ra of a surface of the charging member is 0.1 μm or more and 10 μm or less. When the Martens hardness of the surface of the charging member is HMR, the dispersion degree indicating the range of variation of the Martens hardness of the surface of the charging member is σ, and the Martens hardness of the surface of the developer is HMD,
HMD> HMR + 3σ
The image forming apparatus according to claim 1, wherein the relationship is satisfied.   8. The charging member according to claim 1, wherein the surface of the charging member is deformed so that the developer remaining on the image carrier is bitten at a contact position with the image carrier. The image forming apparatus described in 1. Furthermore, it has a developing blade that abuts against the developing member and uniformly thins the developer,
The relationship between the contact positions from the top in the direction of gravity is the contact position between the image carrier and the charging member, the contact position between the image carrier and the developing member, and the contact position between the developing member and the developing blade. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided.   The image forming apparatus according to claim 1, wherein the charging member is a charging roller. An image carrier, a charging member that contacts the image carrier and charges the image carrier, and a developing member that contacts the image carrier and supplies developer In the cartridge for collecting the developer remaining on the image carrier after the transfer by the developing member,
When the Martens hardness of the surface of the charging member is HMR and the Martens hardness of the surface of the developer is HMD,
HMD> HMR
A cartridge characterized by the above relationship. Furthermore, it has a developing blade that abuts against the developing member and uniformly thins the developer,
The relationship between the contact positions from the top in the direction of gravity is the contact position between the image carrier and the charging member, the contact position between the image carrier and the developing member, and the contact position between the developing member and the developing blade. The cartridge according to claim 11, wherein there is a cartridge. A cartridge having a charging member that contacts the image carrier and charges the image carrier, wherein the Martens hardness of the surface of the charging member is HMR, and the Martens hardness of the surface of the developer carried on the image carrier. When SMD is HMD,
HMD> HMR
A cartridge characterized by the above relationship.   The cartridge according to any one of claims 11 to 13, wherein the surface of the charging member has a Martens hardness HMR of 0.5 or more and 19 or less.   The cartridge according to any one of claims 11 to 13, wherein the surface of the charging member has a Martens hardness HMR of 1 or more and 10 or less.   The cartridge according to any one of claims 11 to 15, wherein a Martens hardness HMD of the surface of the developer is 2 or more and 50 or less.   The cartridge according to any one of claims 11 to 15, wherein a Martens hardness HMD of a surface of the developer is 2.5 or more and 20 or less.   18. The cartridge according to claim 11, wherein an arithmetic average roughness Ra of the surface of the charging member is 0.1 μm or more and 10 μm or less. When the Martens hardness of the surface of the charging member is HMR, the dispersion degree indicating the range of variation of the Martens hardness of the surface of the charging member is σ, and the Martens hardness of the surface of the developer is HMD,
HMD> HMR + 3σ
The cartridge according to claim 11, wherein the relationship is satisfied.   20. The surface of the charging member is deformed so that the developer remaining on the image carrier is bitten at a position in contact with the image carrier. Cartridge.   The cartridge according to any one of claims 13 to 20, wherein a developer cartridge that accommodates the developer is detachable.   The cartridge according to any one of claims 13 to 20, wherein a developing device having a developer carrying member for carrying a developer is detachable.   The cartridge according to any one of claims 11 to 22, wherein the charging member is a charging roller.