JP2010266811A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, capable of properly maintaining the load of a cleaning blade by causing lubricant uniformly applied on the surface of an image carrier to be a proper lubricant replacement amount, according to the usage condition. <P>SOLUTION: In the image forming apparatus including the image carrier as a body to be cleaned, a charging means to which an AC bias is applied, and a cleaning means including an elastic blade cleaning the surface of the image carrier, the lubricant is supplied to the image carrier, and the lubricant is supplied in an amount defined by discharge current amount Idis of the charging means and the surface velocity V of the image carrier. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, which forms an image using an electrophotographic process.

In a conventional general image forming apparatus, an electrophotographic photosensitive member (photosensitive member) which is an image carrier is uniformly charged by a charging means such as a charging roller, and image exposure, for example, a laser beam is applied thereto. To obtain an electrostatic latent image. This latent image is developed as a toner image by reversal development or normal development by the developing means to be visualized. This toner image is electrostatically transferred to a recording medium by a transfer means such as a transfer roller, and then fixed on the recording medium by applying heat and pressure by a fixing means such as a heat fixing device. The toner remaining on the surface of the photoconductor after the toner image is transferred to the recording medium is removed and cleaned by a cleaning device, and is prepared for the next image forming process.
As a cleaning method for removing untransferred toner from the surface of the photoconductor after the toner image has been transferred, cleaning using an elastic blade (cleaning blade) made of polyurethane or the like is often employed.

In the market, there is a demand for an image forming apparatus with high image quality and long life, and from the viewpoint of long life, a technique such as applying an AC bias to the charging means has been taken for stable charging. Yes. On the other hand, a photoconductor as an image carrier is an organic photoconductor having an amorphous silicon photoconductor (a-Si) and a surface protective layer (OCL) in order to suppress the above-described AC bias and mechanical wear due to a contacting member. A photoconductor excellent in wear resistance such as a body (OCL-OPC) is used.
However, particularly in the charging method in which an AC bias is applied, a large amount of charged product is generated and adheres to the image carrier, so that a so-called image flow in which an image is blurred particularly in a high humidity environment is likely to occur.
As a technology for suppressing image flow and maintaining the life of the image carrier for a long time, there is a technology for pre-applying lubricant to the image carrier and further specifying the coating amount and coverage per unit area. It has been proposed (Patent Documents 1 and 2).

Further, an object to be charged having a specified elastic deformation rate was used, and the amplitude (peak-to-peak voltage) Vpp, frequency f, surface velocity v of the image carrier, and discharge threshold voltage Vth applied to the charging means were set. Occasionally, the fatty acid metal salt, and detecting the amount of the metal elements of the fatty acid metal salt is ^{1.52 × 10 -4 × (Vpp-} 2 × Vth) × f / v or more and comprising an amount of supplying technology is proposed (Patent Document 3).
As a technique for suppressing the image flow, maintaining the life of the image carrier for a long time, and further suppressing the wear of the cleaning means, inorganic fine particles having a particle size of 30 to 500 [nm] are used, and a fatty acid metal salt is imaged. There has been proposed a technique for supplying the surface of the image carrier in an amount not less than the amount specified by the surface roughness of the carrier (Patent Document 4).

In addition, a technique has been proposed in which the contact angle and 100 [%] modulus of the cleaning blade are defined to suppress an increase in friction between the cleaning blade and the image carrier (Patent Document 5).
However, even in these image forming apparatuses, if the Vpp applied to the charging means is increased in order to improve the charging uniformity, or if the speed is increased in order to improve the productivity, image defects such as defective cleaning and toner fixation will occur. May occur.

Japanese Laid-Open Patent Publication No. 2008-122870 Japanese Laid-Open Patent Publication No. 2008-139804 Japanese Laid-Open Patent Publication No. 2005-249901 JP 2008-129401 PR JP 2006-267299 A

In a system in which a lubricant such as a fatty acid metal salt is uniformly applied to the surface of the image carrier, the lubricant is deteriorated by being discharged by a charging means or the like. For this reason, friction increases and the cleaning blade or the image carrier may be worn out.
Therefore, it is important to replace the lubricant applied to the surface of the image carrier in accordance with the deterioration caused by the discharge exposure so that the deterioration does not proceed excessively.
Even when the surface of the image carrier is the same, the load on the cleaning blade differs depending on the surface speed, which affects the blade life.
An object of the present invention is to provide an image forming apparatus that solves the above-described problems. That is, an object of the present invention is to appropriately maintain the load of the cleaning blade by setting the lubricant uniformly applied to the surface of the image carrier to an appropriate amount of lubricant replacement according to the use conditions.

The above object can be achieved by the following means.
That is, the image carrier is brought into contact with or close to the image carrier, and a charging means for charging the image carrier by applying an oscillating voltage, and the latent image formed on the image carrier is developed by a developer. An image forming apparatus comprising: a developing unit that forms an image; a transfer unit that transfers the visible image to a recording medium; and a cleaning unit that includes an elastic blade for removing the transfer residual developer from the surface of the image carrier after the transfer. In this case, the surface of the image carrier is supplied with a lubricant and has the following configuration.
(1) The supply amount of the lubricant is Mz [mg / m ² ], the discharge current amount per unit length in the longitudinal direction flowing from the charging means to the image carrier is Idis [mA / m], and the image carrier When the surface speed is V [m / sec],
Mz ≧ Az × Idis × V + Bz (1)
Mz ≦ 5 (2)
[However, when Idis × V ≦ 0.1, Az is 0.66 and Bz is 0.004, and when Idis × V> 0.1, Az is 2.72 and Bz is −0. 202. ]
It is characterized by being.
(2) The surface of the image carrier is further supplied with inorganic fine particles, the supply amount of the inorganic fine particles is Ms [mg / m ² ], and the discharge per unit length in the longitudinal direction flowing from the charging means to the image carrier. When the current amount is Idis [mA / m] and the surface velocity of the image carrier is V [m / sec], the following equation is satisfied.
Ms ≧ As × Idis × V + Bs (3)
Ms ≦ 15 (4)
[However, when Idis × V ≦ 0.1, As is 1.00 and Bs is 0.100, and when Idis × V> 0.1, As is 2.48 and Bs is −0. 048. ]
(3) A lubricant supply unit that supplies the lubricant is provided downstream of the transfer unit and upstream of the elastic blade of the cleaning unit in the rotation direction of the image carrier.
(4) The lubricant is a fatty acid metal salt.
(5) The fatty acid metal salt is zinc stearate.
(6) The number average primary particle size of the inorganic fine particles is 50 [nm] or more and 300 [nm] or less.
(7) The ratio of the specific gravity of the inorganic fine particles to the specific gravity of the lubricant ([specific gravity of inorganic fine particles] / [specific gravity of lubricant]) is 2 or more and 5 or less.
(8) The lubricant supply means is a lubricant supply means including a solidified lubricant and a rotatable brush-like member.
(9) The wear rate of the image carrier is 0.3 [μm / 100k rotation] or less.
(10) Rz on the surface of the image carrier is 0.1 [μm] or more and 1.0 [μm] or less.
(11) The elastic member constituting the elastic blade has a 100% modulus of 2940 [kN / m ² ] or more and 5880 [kN / m ² ] or less (that is, 30 [kgf / cm ² ] or more and 60 [kgf / cm ^2]. And the like, and the elongation at break is 300% or more.
(12) The contact pressure between the lubricant and the brush-like member is variable.
(13) The inorganic fine particle supplying means is a developing means.
(14) The surface velocity of the image carrier is from 0.1 [m / sec] to 0.5 [m / sec].

With the configuration of the present invention, it is possible to prevent excessive deterioration of the lubricant uniformly applied to the surface of the image carrier with a simple and small configuration. This prevents an increase in the load received by the cleaning blade and wear of the cleaning blade, maintains a stable and good cleaning property over a long period of time, prevents image defects such as image flow and toner fixation, and stabilizes. Image characteristics are maintained at a high level. Moreover, the maintenance load can be reduced by these.
In particular,
With the configuration of (1), by setting the amount of lubricant to be in a suitable range defined by the discharge current and the surface speed of the photoreceptor, it is possible to suppress the accumulation of excessive deterioration of the lubricant and reduce the wear of the cleaning blade. Can be prevented and good cleaning properties can be maintained.
With the configuration of (2), the cleaning blade wear and slippage are further improved by supplying the inorganic fine particles at a suitable supply amount defined by the discharge current and the surface speed of the photoreceptor.
According to the configuration of (3), filming and dependence are reduced by having the lubricant supply means downstream of the transfer means and upstream of the cleaning means.
According to the configuration of (4), when the lubricant is a fatty acid metal salt, it is excellent in spreading and scraping properties, and also has high transparency as a surface layer.
With the configuration of (5), wear of the cleaning blade can be further suppressed by using zinc stearate as the lubricant.
By defining the particle size of the inorganic fine particles by the configuration of (6), abnormal noise and slipping are suppressed. With the configuration of (7), the cleaning blade is prevented from being worn by using the lubricant and the inorganic fine particles in a specific combination.
With the configuration (8), it is possible to stably control the supply of lubricant for a long period of time, and it is advantageous for downsizing the apparatus.
With the configuration (9), changes in the surface shape of the photosensitive member are suppressed, and slipping through and filming are improved.
With the configuration (10), abnormal noise and vibration are improved.
With the configuration (11), by using a cleaning blade that is unlikely to be deformed abnormally and that is unlikely to be worn even if deformed, wear of the cleaning blade is suppressed.
With the configuration (12), slip-through is improved.
With the configuration of (13), filming and abnormal noise are suppressed.
With the configuration (14), it is possible to stably adjust the friction characteristics in each of the above configurations, and it is possible to suitably suppress the wear of the cleaning blade.

1 is an example of an embodiment of an image forming apparatus according to the present invention. 1 is an example of an embodiment of an image forming apparatus according to the present invention. 1 is an example of an embodiment of an image forming apparatus according to the present invention. 1 is an example of an embodiment of an image forming apparatus according to the present invention. The figure which shows an example of the installation state of the cleaning apparatus of this invention. An example of an apparatus for measuring a frictional force of a contact portion between a cleaning blade and an image carrier. The figure which shows the suitable range of Idis * V and lubricant amount concerning this invention. The figure which shows the suitable range of Idis * V and lubricant amount concerning this invention. FIG. 3 is a model diagram for explaining a contact state between a cleaning blade and an image carrier. The figure for demonstrating the model of the wear shape of a cleaning blade, and the object position of evaluation. FIG. 10A is an example of a worn state of the cleaning blade, FIG. 10B is a cross-sectional model view of the blade in the state of FIG. 10A, and FIG. 10C is another example of the worn state of the cleaning blade. FIG.10 (d) is a blade cross-section model figure in the state of (c). FIG. 3 is an equivalent circuit diagram of a charging unit and an image carrier at a charging site. The model figure which shows the relationship between an alternating voltage and discharge current. The electron microscope (SEM) observation figure of an example of inorganic fine particles concerning this invention. The model figure which shows the layer structure of the image carrier concerning this invention. The figure for description of the original chart used in the Example of this invention. FIG. 15A is a diagram for explaining a document chart used for durability. FIG. 15B is a diagram for explaining the original chart used in severe operation. The figure which shows the evaluation result of the standard deviation of the surface speed of a photoconductor and dynamic friction force concerning this invention.

Hereinafter, the present invention will be described in detail.
The image forming apparatus of the present invention includes an image carrier, a charging unit that is in contact with or close to the image carrier, and is applied with an oscillating voltage to charge the image carrier, and a latent image formed on the image carrier. Developing means for developing an image with a developer, transfer means for transferring the developed image to a recording medium, and cleaning means having an elastic blade for removing the transfer residual developer from the surface of the image carrier after transfer And an image forming apparatus.
(1) Configuration of Image Forming Apparatus FIG. 1 shows an outline of an image forming apparatus according to the present invention.
The image carrier 101 is a rotatable drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive member), and is rotationally driven in a direction indicated by an arrow X at a predetermined surface speed by a driving mechanism (not shown). The photoreceptor 101 is formed by applying a photosensitive layer such as OPC to the surface of a cylindrical conductive substrate.
Around the photosensitive member 101, a charging unit 102 for charging the image carrier, a latent image forming signal 103 added by a latent image forming unit (not shown), a developing unit 104, a transfer unit 105, and a cleaning blade 107 which is an elastic blade. A cleaning means 106 comprising:
If necessary, a charge eliminating unit (not shown) may be provided downstream from the transfer unit 105 and upstream from the charging unit 102. The electric memory at the time of image formation on the photoconductor 101 is erased by the charge eliminating means. Further, when the charge eliminating unit is disposed upstream of the cleaning unit 106, the electrostatic adhesion force of the transfer residual developer or the like to the photosensitive member 101 is further reduced.

(2) Charging unit The photosensitive member 101 is uniformly charged by the charging unit 102 that is in contact with or close to the photosensitive member 101. The charging unit 102 is provided with a bias applying unit (not shown), and an oscillating voltage obtained by superimposing a predetermined DC voltage on a predetermined AC voltage is applied as a charging bias (AC method).
The charging unit 102 is a roller-type charging member (also referred to as a charging roller 102) and is arranged in contact with the photosensitive member 101 in a direction substantially parallel to the generatrix. The charging roller 102 is rotated following the rotation of the photosensitive member 101. The charging roller 102 includes a cylindrical or columnar conductive member (core metal) such as iron or stainless steel, and a volume specific resistance 1 × 10 ⁴ to 1 formed in a roller shape around the conductive member. It is composed of a resistance layer of × 10 ¹² [Ω · cm]. Further, a surface protective layer having a volume resistivity of 1 × 10 ⁴ to 1 × 10 ¹² [Ω · cm] may be provided so as to cover the surface of the resistance layer.
The charging unit 102 is not limited to the roller type as described above, but may be a blade type, a fur brush type, or a magnetic brush type. Further, the charging device is not limited to the contact charging device, and is a proximity charging device in which the charging member is arranged in a non-contact manner with a small gap of about several tens to several hundreds [μm] with respect to the surface of the photoreceptor 101. Also good.
In this example, charging is performed so that the dark portion potential VD of the photoconductor 101 becomes −700 [V] at a position facing a developing unit 104 described later.
Of the oscillating voltage applied to the charging roller 102, the frequency f of the AC voltage is set to improve the charging stability so that the streak image (charging moire) does not occur due to charging. The dark portion potential is adjusted as appropriate according to the surface speed of the photosensitive member 101 and the conditions of the charge eliminating means.
The Vpp is generally set to a level that does not cause dielectric breakdown and to be equal to or higher than a threshold value according to the above conditions.

(3) Latent image formation signal After the photoreceptor 101 is uniformly charged by the charging means 102, a latent image is formed by a latent image formation signal 103 according to image information. As the latent image forming signal, a known signal such as laser light or LED light can be used.
In general, an image exposure method for exposing an image portion is often used in combination with reversal development, and the image exposure method is also used in this example. In addition, a latent image is formed so that the bright portion potential VL of the photosensitive member 101 is −200 [V] at a position facing a developing unit 104 described later.

(4) Developing means In this embodiment, the developing means 104 uses a so-called non-magnetic two-component developing system in which the developer is a mixture of a non-magnetic negative toner and a magnetic carrier.
In the developing means 104, a nonmagnetic toner and a magnetic carrier are mixed and fed as an initial developer so that the toner becomes 8 [mass%].
The developing sleeve is non-magnetic and contains a fixed magnet roller. The developer conveyed by the developing sleeve comes into contact with the photoreceptor 101 at a predetermined developing nip. The developing sleeve is driven at a surface speed of 150% with respect to the photoreceptor 101, and a predetermined developing bias is applied from a developing bias power source (not shown). In this example, a DC voltage of −450 [V] and an AC voltage of a peak-to-peak voltage of 1.5 [kV] are applied to the developing bias. The frequency is appropriately adjusted according to the surface speed of the photosensitive member 101.

(5) Transfer means The toner image on the photosensitive member 101 is transferred to the transfer material P by the transfer means 105. A bias having a polarity opposite to that of the toner is applied to the transfer unit 105, and a positive polarity bias is applied in this example. In this example, a belt-shaped primary transfer material (transfer belt) is used as the transfer material P. The transfer material P is not limited to the primary transfer belt, and may be a transfer drum or the like, or a final transfer material such as paper.

(6) Cleaning means The surface of the photosensitive member 101 after transfer is removed by the cleaning means 106 to remove residues such as a transfer residual developer and paper dust, and is used for the next image forming process.
The cleaning means 106 has a cleaning blade 107 made of an elastic member such as polyurethane rubber.
The cleaning blade 107 is made of polyurethane rubber, and is held by a cleaning blade holding unit (not shown), and is brought into contact with the photosensitive member 101 with a predetermined contact pressure or amount of entry and a set angle θ. The rubber hardness of the cleaning blade 107 is preferably 50 to 85 [°] (JIS A), and more preferably 60 to 80 [°].
The contact pressure is preferably 9.8 to 78.4 [N / m] (10 to 80 [g / cm]). When the contact pressure of the cleaning blade 107 is less than 9.8 [N / m], a cleaning failure due to toner slip is likely to occur, and when it exceeds 78.4 [N / m], the cleaning blade 107 Vibrations, abnormal noise (chattering noise), and wear of the cleaning blade 107 or the photosensitive member 101 make it difficult to obtain satisfactory durability.
The set angle θ is preferably 20 to 40 [°]. When the set angle θ is less than 20 [°], the toner easily slips through, and when it exceeds 40 [°], the cleaning blade 107 is likely to sag.
In this example, the cleaning blade 107 is a system in which a plate-like blade having a thickness of 2 [mm] is fixed to a sheet metal, and the sheet metal is brought into contact with the photosensitive member 101 by spring pressure. The cleaning blade and its holding method are not limited to this, and may be a so-called chip blade that is integrally held at the front end of the sheet metal, or may be fixedly brought into contact with a predetermined amount of penetration. Further, an equalizing mechanism, a reciprocating mechanism, or the like may be added as necessary.

Further, the lubricant is applied mainly at the contact portion between the cleaning blade 107 and the photosensitive member 101. Further, a part is scraped off by the cleaning blade 107. Therefore, it is preferable that the cleaning blade 107 has little shape change and high scraping ability.
On the other hand, the wear of the cleaning blade is considered to be caused by abrupt pulling of the cleaning blade at the contact portion with the photosensitive member due to an increase in local friction or foreign matter or abnormal load. In particular, when the amount of lubricant is controlled as in the present invention to replace a lubricant that has deteriorated due to discharge or the like with a new lubricant, or when inorganic fine particles are supplied to stir and scrape the lubricant, etc. When the replacement is performed, the friction characteristics may be locally uneven in the longitudinal direction. Therefore, it is preferable that the cleaning blade is not easily deformed and has strength against breakage such as tearing or cutting even if it is deformed. However, it is needless to say that the cleaning performance is not impaired.

Here, the elastic member (rubber) constituting the elastic blade (cleaning blade) has a 100% modulus of 2940 [kN / m ² ] or more and 5880 [kN / m ² ] or less (that is, 30 ≦ 100% modulus ≦ 60). [Kgf / cm ² ]) and the elastic member (rubber) has a breaking elongation in the range of 300 [%] to 420 [%], so that the state of the coating film by the lubricant is suitably maintained. This is preferable because it can suppress wear of the cleaning blade.
The 100% modulus is an index of resistance to deformation due to pressure when the cleaning blade 107 is brought into contact with the photosensitive member 101 with a force necessary to stretch the elastic member (rubber) by 100%. When the 100% modulus is 2940 kN / m ² (30 kgf / cm ² ) or more, changes in the shape of the abutting portion of the cleaning blade, extreme deformation when a local load occurs, and drooling can be suppressed. On the other hand, if it exceeds 5880 kN / m ² (60 kgf / cm ² ), the followability to the surface shape of the photoconductor 101 may be deteriorated, and a cleaning defect may easily occur.
On the other hand, the elongation at break is the length that elongates until tearing occurs when the rubber is stretched. Having a rubber physical property of breaking elongation of 300 [%] or more is effective in maintaining cleaning properties without causing wear even when local deformation occurs. When the elongation at break is large, the followability to the photosensitive member, that is, the adhesion, increases, so that the frictional force increases, and as a result, the wear of the cleaning blade tends to increase. For this reason, the elongation at break is preferably 450% or less. Furthermore, if it is 420 [%] or less, the wedge shape at the tip of the portion where the cleaning blade and the photosensitive member abut is maintained, and as a result, the state of the coating film by the lubricant can be preferably maintained.
The 100% modulus and elongation at break of the elastic member (rubber) are values measured according to JIS K6251. Although it can measure with the commercially available apparatus based on a JIS specification, specifically, it measured with the autograph (made by Shimadzu Corporation), and the test piece used the No. 3 type of the dumbbell-shaped test piece.

In addition to the cleaning blade 107, the cleaning unit 106 includes a rotatable brush-like member (hereinafter referred to as a cleaning brush) 108, a solidified lubricant or lubricant reservoir 109, a flicker 111, and a waste toner conveying unit 112. You may have. That is, the cleaning unit 106 may include a lubricant supply unit for supplying a lubricant, which includes the solidified lubricant or the lubricant reservoir and the rotatable brush-like member. The lubricant supply means may be provided in the cleaning means 106 or may be provided separately from the cleaning means 106. However, the lubricant supply means for supplying the lubricant is preferably provided downstream of the transfer means and upstream of the elastic blade of the cleaning means in the rotation direction of the image carrier. The lubricant is preferably a solidified lubricant.

On the other hand, the cleaning brush 108 is disposed downstream of the transfer unit 105 in the traveling direction of the photoconductor 101. As the brush fiber, rayon, acrylic, polyester or the like is preferably used, and conductivity may be imparted by including carbon or metal powder. The brush portion has a thickness of 3.33 [Tex] (30 [denier]) or less and a density of 1550 to 77500 [lines / cm ² ] (so that it can uniformly contact the surface of the photoreceptor and the transfer residual toner. 1 to 50 [10,000 / inch ² ]) is preferable. The cleaning brush 108 is driven by a driving means (not shown) with a relative speed difference from the photoconductor 101, and contributes as a cleaning aid by the cleaning blade 107 in addition to applying a lubricant described later to the photoconductor 101.
The amount of penetration and the driving speed when the cleaning brush 108 abuts on the photoconductor 101 depends on the fiber condition of the cleaning brush 108 and the condition of the photoconductor 101, but the amount of penetration is 3 [mm] or less. Preferably used. If the penetration amount is too large, the fibers of the photoconductor 101 or the cleaning brush 108 may be easily worn out. Furthermore, it is preferable that the thickness is 0.5 [mm] or more because it contributes to the removal of foreign matter by contact with the photoreceptor 101.
The drive speed is preferably about 5 to 20% relative to the surface speed of the photoconductor 101 in terms of the difference in relative speed with the photoconductor. In a state where there is almost no speed difference of less than 5%, the rubbing with the cleaning brush 108 and the supply of the lubricant 109 are likely to be uneven. On the other hand, if it exceeds 20%, the load at the contact portion between the cleaning brush 108 and the photoconductor 101 becomes excessive, and the cleaning brush 108 or the photoconductor 101 may be easily worn.
A solid lubricant (solidified lubricant block body) 109 is disposed in contact with the cleaning brush 108. Reference numeral 110 denotes an urging means for always bringing the solid lubricant 109 into contact with the cleaning brush 108 with a predetermined pressing force.
By making the contact pressure between the lubricant and the brush-like member variable, it becomes possible to control the supply amount of the lubricant by the contact pressure of the brush member, and to supply the lubricant stably over a long period of time. Therefore, it is preferable for maintaining the cleaning property for a long time.

As the solidified lubricant, zinc stearate having a pencil hardness of HB to B and molded into a block shape was used. If it is too soft, it may cause excessive supply locally due to the contact state of the supply means, or supply to the surface of the photoconductor 101 as a powder lump, which may cause cleaning failure. Further, the consumption of the solidified lubricant increases, and satisfactory durability as a unit cannot be obtained. On the other hand, if it is too hard, it is difficult to uniformly supply the film and it is difficult to form a uniform film. Further, it is necessary to harden the brush for scraping, which may lead to wear of the photoconductor 101.

The flicker 111 is for removing foreign matter adhering to the cleaning brush 108. Moreover, it contributes also to provision of the tip force for writing down the solidified lubricant depending on the installation position and angle. As the flicker 111, a known one can be used.
Foreign matter removed by the cleaning blade 107, the cleaning brush 108, etc., excess lubricant, and the like are discharged to a waste toner container (not shown) by a waste toner transport unit 112 provided as necessary. Although a mechanism for discharging waste toner is shown in this example, the present invention is not limited to this, and a cartridge system in which waste toner is accommodated in the cleaning unit 106 and replaced with the cleaning unit may be used.

The wear of the cleaning blade 107 generally becomes a shape that is cut out in the cross-sectional method of the cleaning blade, such as a shaded portion in FIG. There are many. So-called chips can also be roughly classified into any of the above sections. As shown in FIGS. 10B and 10D, the cleaning blade wear depth was D [μm] and the width was W [μm]. D and W were measured, and the product DW [μm ² ] was used as an index of wear.
The D and W were obtained by observing and measuring the cleaning blade 107 from the 107a direction and 107b direction using a 3D laser microscope (VK-8700: manufactured by Keyence Corporation). The objective lens was observed in steps of 50 to 20 [times] and a depth of 0.1 [μm] depending on the magnitude of wear.

(7) Lubricant The lubricant is easily stretched at the nip portion between the cleaning blade 107 and the photosensitive belt 101 to form a thin film on the photosensitive member, thereby improving the cleaning performance by the cleaning blade. It also prevents filming and toner sticking due to the external toner additive. Further, it is effective in preventing image flow by protecting the surface of the photoreceptor from discharge damage.
The lubricant needs to be applied substantially over the entire surface of the photoreceptor in order to improve the cleaning performance by the cleaning blade and prevent the charged product generated by the charging means from directly adhering to the photoreceptor surface. is there. Further, the charged product adheres to the lubricant, and in a high-humidity environment, the resistance is reduced in the same manner as the surface of the photoreceptor. Further, since it is applied to the outermost surface of the photosensitive member, it is necessary to transmit light such as image exposure and static elimination light and not to impede charging, development, transfer, and cleaning processes. Therefore, the lubricant is required to have a film that can be easily formed as a so-called disposable surface layer (soft and easy to spread), easy to scrape, transparency of the film, and appropriate resistance.
From these physical properties, examples of the lubricant include powder, a block obtained by solidifying the powder lubricant, or a liquid fatty acid metal salt, fluororesin, silicone oil, and the like. Among these, higher fatty acid metal salts (so-called metal soaps) such as zinc stearate, aluminum stearate, calcium stearate and the like are preferably used. In particular, zinc stearate is preferable because it is excellent in each of the above-described properties and is easy to process into a block body.
Also, a wax mainly composed of higher fatty acid and higher alcohol ester is preferably used.
As a means for supplying the lubricant to the surface of the photosensitive member 101, a method of externally adding a lubricant having a predetermined particle diameter to the developer may be used in addition to the method of providing the lubricant supply means in the cleaning device described above. Is possible. Also in this case, the lubricant may be used not only in the form of powder but also in a predetermined shape.

(8) Inorganic fine particles (polishing agent)
When inorganic fine particles are used in combination with the lubricant, it is preferable to uniformly apply and replace the lubricant by, for example, rubbing and polishing the lubricant film exposed to the inorganic fine particles and stirring the newly supplied lubricant. Promoted and preferred.
The inorganic fine particles preferably have high hardness and excellent polishing performance. For example, strontium titanate, barium titanate, and calcium titanate are used.
In particular, the inorganic fine particles exhibit a particularly excellent polishing action when the particle shape is cubic and / or rectangular parallelepiped. This is because the particle shape is cubic and / or rectangular parallelepiped, the contact area with the object can be increased, and the cubic or rectangular parallelepiped ridge line is in contact with the object, which is favorable. This is thought to be due to the ability to obtain scraping.

Furthermore, since the number average particle size of the primary particles of the inorganic fine particles (that is, the number average primary particle size of the inorganic fine particles) is 50 [nm] or more and 300 [nm] or less, the polishing effect is excellent. preferable. Further, the inorganic fine particles having the number average primary particle diameter pass through the contact portion in a minute amount, and contribute to a lubrication effect on the contact portion between the cleaning blade 107 and the photosensitive member 101. About the number average primary particle size of the inorganic fine particles, 100 particle sizes were measured from a photograph taken at a magnification of 50,000 times with an electron microscope, and the average was obtained. The particle size was determined as (a + b) / 2 where a is the longest side of the primary particles and b is the shortest side.
When the number average primary particle size is less than 30 [nm], the polishing effect of the inorganic fine particles is insufficient. On the other hand, when the number average primary particle size is more than 300 [nm], the photoconductor is scratched or the cleaning blade is worn out. There is a case.
As a means for supplying the inorganic fine particles to the surface of the photoreceptor 101, in addition to a method for providing the inorganic fine powder supply means in the cleaning means 106, for example, a method of externally adding to the developer (that is, an inorganic fine particle supply means) Is a developing means), but is not particularly limited.
In the case where inorganic fine particles are added to the developer, from the viewpoint of the function as a so-called developer, such as the development density and transferability, an amount such that the liberation rate with respect to the toner particles is 20 [volume%] or less, and / or It is preferable to be added with strength, and more preferably 15% by volume or less. Here, the liberation rate is a ratio obtained by volume% of the perovskite crystalline inorganic fine particles liberated from the toner particles, and is known by a particle analyzer (PT1000: manufactured by Yokogawa Electric Corporation) (for example, Japan). Hardcopy 97, 65-68 (Publisher: Electrophotographic Society, issue date: July 9, 1997)).
It is also preferable to adjust the resistance of the inorganic fine particles as necessary. The resistance adjustment can be controlled by a known method such as coating the core particles of the produced inorganic fine particles with tin oxide having a controlled degree of oxidation. The resistance of the inorganic fine particles can be obtained by measuring and normalizing by the tablet method. For example, a powder sample of 0.5 [g] is placed in a cylinder with a bottom area of 2.26 [cm ² ], and 147 N (15 [kgf]) is applied to the upper and lower electrodes, and at the same time, 100 [V] and The volume resistivity can be calculated by applying a voltage of 500 [V], measuring each resistance value, and then normalizing.
The ratio of the specific gravity of the inorganic fine particles to the specific gravity of the lubricant ([specific gravity of inorganic fine particles] / [specific gravity of lubricant]) is preferably 2 or more and 5 or less. By setting the value of the ratio within a specific range, the inorganic fine particles suitably push the aggregate or coating of the lubricant fine particles, reach the contact portion between the cleaning blade 107 and the photosensitive member 101, and scrape the lubricant. It is thought that it works suitably.

(9) Image carrier A known photoconductor can be used as the image carrier 101. However, when the amount of wear is small, the surface shape is maintained for a long period of time, and the above various inorganic fine particles and the like are slipped through. It is preferable because durability fluctuation is reduced.
The wear amount can be controlled by the system of the image forming apparatus, such as cleaning setting, setting of charging means, use of the above-described lubricant, and the like. In addition, when an image carrier having excellent wear resistance is used, the surface shape is more suitably maintained and effective even in the same system.
As an image carrier excellent in abrasion resistance, an organic photoreceptor (referred to as OCL-OPC) having a curable surface protective layer cured by a known electron beam, light, heat or the like, or an amorphous silicon type (
A photoconductor (referred to as a-Si) can be preferably used.
Further, if the surface shape Rz of the photoconductor 101 is too large, the lubricant is not uniformly applied or formed into a film, or the deteriorated lubricant is not scraped off or rubbed by the cleaning blade, inorganic fine particles or the cleaning brush. It may become easy to become uniform. On the other hand, if Rz is too small, toner particles and external additives may adhere to the image carrier and filming and the like may occur easily. Further, the toner may be fixed, resulting in an image defect. Although depending on the configuration of the cleaning means and use conditions, the surface roughness Rz of the image carrier is preferably 0.1 [μm] or more and 1.0 [μm] or less from the above viewpoint. The Rz is preferably in the above range from the beginning through endurance.
The surface shape of the image carrier 101 was adjusted by polishing the surface of the photoreceptor after film formation in the circumferential direction using a commercially available polishing tape.
Note that the wear rate of the image carrier 101 is preferably 0.3 [μm / 100 k rotation] or less because the change in the surface shape Rz of the image carrier can be suppressed and the slipping through and filming can be improved. The wear rate [μm / 100k rotation] of the image carrier 101 is measured by measuring the film thickness with an eddy current film thickness meter (Fischerscope GROUNDEINITIT MMS 3AM: manufactured by Ficher) before and after the endurance of the examples described later. The amount of wear per revolution [μm] was calculated.
The surface shape Rz of the image carrier 101 is Rz defined by JISB0601: 1994. The surface roughness was measured using a surface roughness measuring instrument (SURFPAK-SV4000S4: manufactured by Mitutoyo Corporation), measuring length 2.50 [mm], number of measurements 5 [times], height direction full scale 8 [μm], filters Gaussian, λc = 0.25, λs = 0.008, measurement speed = 0.1 [mm / sec], and measured by scanning in the longitudinal direction in JIS 1994 RLS_JIS mode. For both the film thickness and the surface shape, measurements were made for a total of 40 points of 8 points in the circumferential direction and 5 points in the longitudinal direction, and the average value was taken as each value.
The surface shape of the image carrier 101 can be adjusted by a known method such as changing the polishing direction or blasting in addition to the circumferential polishing process described above. In that case, the surface shape is measured not only in the longitudinal direction but also in the circumferential direction, and Rz is preferably in the above range.

(10) Developer The developer contains at least toner particles and an external additive. Furthermore, as in this example, the two-component developer has toner particles to which external additives have been added (hereinafter simply referred to as toner) and carrier particles. Known toners and carrier particles can be used.
The toner particles preferably have a mass average particle diameter of 4 to 12 [μm] from the viewpoints of high image quality and cleaning properties. In view of image quality such as transferability, the average circularity of the toner particles is preferably 0.930 or more. On the other hand, if it is 0.980 or less, cleaning is easy. In addition, each toner particle is easily subjected to a rotational load in a different direction, and the toner particles are easily diffused in the cleaning unit. When a lubricant or inorganic fine particles are externally added to the toner particles, the diffusion of the toner particles is promoted with the diffusion of the toner particles, and the uniformity in the longitudinal direction is also improved.

(11) Cleaning blade wear Here, the qualitative explanation of the present invention will be given.
As a result of investigations, the present inventors have found that variations in the load that the cleaning blade 107 receives during operation correlate with poor cleaning, particularly chatter, turning, and wear of the cleaning blade 107.
This will be described with reference to FIG. The cleaning blade 107 contacts the photosensitive member 101 with a predetermined contact pressure (a). During the cleaning operation, that is, when the photosensitive member 101 is driven, the cleaning blade 107 is distorted by receiving a load in the X direction so as to be dragged to the surface of the photosensitive member 101 at the contact portion with the photosensitive member 101 (b). ). When distortion occurs to some extent, the original state (a) is restored by the elasticity of the cleaning blade 107. By repeating this process, the cleaning blade 107 receives a load on the edge portion or the surface facing the upstream side in the direction of movement of the photosensitive member, and so-called cleaning blade wear such as erosion and edge portion chipping occurs.
Further, a local load may be unevenly applied depending on the transfer residue or the surface state of the photoconductor 101. In this case, the contact portion is deformed so as to be dragged locally and instantaneously by the photosensitive member 101, and the operation of restoring by stick-slip or the like is repeated. The load received by the cleaning blade at this time varies depending on the state of the lubricant on the surface of the photoreceptor.
As described above, in a system in which a lubricant film is formed as a protective film on the surface of the photoconductor, friction increases even if the lubricant supplied to the surface of the photoconductor does not disappear due to charging accompanying discharge. This is presumably because the lubricant deteriorates due to discharge exposure as a protective film of the photoreceptor 101. When the friction is increased, a cleaning failure is likely to occur or the cleaning blade 107 is easily worn. The degree of deterioration depends on the discharge current Idis, and the larger the Idis, the more the deterioration of the lubricant film is promoted. Therefore, in accordance with Idis, it is necessary to replace the lubricant that has been damaged by the discharge with a new lubricant that has not been deteriorated.

The behavior of the cleaning blade as described above also depends on the surface speed V of the photoconductor 101. Even if the surface condition of the surface of the photoconductor 101 and the contact condition of the cleaning blade 107 are the same, the photoconductor surface speed V Increases, the standard deviation of the dynamic friction force between the cleaning blade 107 and the photosensitive member 101 increases. That is, an abnormally large frictional force is applied to the cleaning blade 107 or the photosensitive member 101 locally or instantaneously.
Therefore, it is necessary to further reduce the load on the cleaning blade 107 in accordance with the photoreceptor surface speed V. That is, as the photoreceptor surface speed V increases, it is necessary to replace the lubricant with less deterioration.
Although depending on the physical properties of the cleaning blade 107, etc., Idis and V increase. As a result, when the standard deviation of the dynamic friction force increases to some extent, the cleaning failure and the cleaning blade wear increase rapidly.

As a result of the study by the present inventors, the tendency of wear of the cleaning blade changes when Idis × V is 0.1 or less and exceeds 0.1, and the amount necessary for supplying the lubricant and inorganic fine particles Found different.
That is, the lubricant supply amount is Mz [mg / m ² ], the discharge current amount per unit length in the longitudinal direction flowing from the charging means to the image carrier is Idis [mA / m], and the surface velocity of the image carrier is V By satisfying the following formulas (1) and (2) when [m / sec], it is possible to adjust to an appropriate lubricant replacement amount according to the use conditions. As a result, it has been found that the load of the cleaning blade can be properly maintained, and it is possible to reduce cleaning failure and wear of the cleaning blade.
Mz ≧ Az × Idis × V + Bz (1)
Mz ≦ 5 (2)
[However, when Idis × V ≦ 0.1, Az is 0.66 and Bz is 0.004, and when Idis × V> 0.1, Az is 2.72 and Bz is −0. 202. ]
The range of Idis × V is preferably 0.1 or more and 0.7 or less. More preferably, it is 0.125 or more and 0.625 or less.
When Idis × V is larger than 0.7, the discharge exposure deterioration of the lubricant is quick, the amount required for replacement increases, and the apparatus may be increased in size and complexity. Further, when the toner is externally added to the developer, the amount of the developer may be increased, and the developer may be liberated in the developing unit, resulting in a decrease in developing properties such as a charging property of the developer. On the other hand, if it is smaller than 0.1, the charging may be non-uniform.
The supply amount of the lubricant is, when solidified lubricant is supplied as a member, measured the weight of the lubricant before and after the printing durability test, and the amount used per unit area from the total rotation amount of the image carrier. Was calculated as the supply amount Mz.
When supplying externally to the developer, the transfer efficiency and the lubricant content of the developer in the cleaning device are measured, and the supplied lubricant is determined from the amount of developer developed in the printing durability. The mass of the agent was calculated, and Mz was determined from the total amount of rotation of the image carrier.
The transfer efficiency was determined from the ratio of the developer on the image carrier measured before and after the transfer. Moreover, the content rate of the lubricant was measured by fluorescent X-rays.
The surface speed of the image carrier was determined by measuring the outer diameter and rotation speed of the image carrier.
On the other hand, a method for calculating the discharge current amount Idis [mA / m] will be described later.
Further, the inorganic fine particles can contribute to stirring of the lubricant, removal of the deteriorated lubricant, and lubrication of the cleaning blade, thereby reducing the load on the cleaning blade. Since the inorganic fine particles pass through the cleaning blade little by little or are separated from the surface of the photoconductor by a cleaning unit or the like, it is also necessary to supply the inorganic fine particles according to the discharge current Idis and the photoconductor surface speed V.
That is, the supply amount of inorganic fine particles is Ms [mg / m ² ], the discharge current amount per unit length in the longitudinal direction flowing from the charging means to the image carrier is Idis [mA / m], and the surface velocity of the image carrier is V It was found that when [m / sec] is satisfied, the following formulas (3) and (4) are satisfied, whereby the wear of the cleaning blade and the slipping of the cleaning blade can be reduced.
Ms ≧ As × Idis × V + Bs (3)
Ms ≦ 15 (4)
[However, when Idis × V ≦ 0.1, As is 1.00 and Bs is 0.100, and when Idis × V> 0.1, As is 2.48 and Bs is −0. 048. ]
Further, Idis × V is preferably 0.1 or more and 0.7 or less. More preferably, it is 0.125 or more and 0.625 or less. When Idis × V is larger than 0.7, the discharge exposure deterioration of the lubricant is quick, the amount required for replacement increases, and the apparatus may be increased in size and complexity. Further, when the toner is externally added to the developer, the amount of the developer may be increased, and the developer may be liberated in the developing unit, resulting in a decrease in developing properties such as a charging property of the developer. On the other hand, if it is smaller than 0.1, the charging may be non-uniform.
In addition, the supply amount (Ms [mg / m ² ]) of the inorganic fine particles is measured by the same method as Mz described above.
Here, the above formulas (1) to (4) will be described qualitatively.
The above formula (1) represents a preferable range for suppressing the load applied to the cleaning blade and preventing vibration, abnormal noise, wear of the cleaning blade, and the like. Further, the above formula (3) represents a suitable amount of inorganic fine particles for promoting the stirring and replacement of the lubricant.
The reason for having an inflection point with respect to Idis × V is not clear, but the discharge exposure increases and the frictional characteristics of the lubricant deteriorate, and the contact portion between the cleaning blade and the image carrier is the image carrier. It is thought that the load of the cleaning blade increases synergistically by being dragged by the body.
On the other hand, according to the above formula (2), it can be prevented that a large amount of the lubricant is constantly supplied, resulting in an excessive amount of the lubricant and the occurrence of abrasion. Further, by the above formula (4), the slipping through can be further improved by suppressing the supply of the inorganic fine particles to a predetermined amount or less.
Suppresses uneven load in the longitudinal direction of the cleaning blade due to excessively localized inorganic fine particles or increased unevenness in scraping the lubricant film, facilitating uniform scraping and stirring. It is thought to be done.

(12) Discharge current Idis
The discharge current Idis flowing from the charging roller 102 to the photoconductor 101 will be described.
As described above, the charging roller 102 is applied with an AC charging bias in which a DC bias is superimposed on a sinusoidal AC bias.
It can be considered that the impedance Zc between the charging roller 102 and the photosensitive member 101 is represented by the equivalent circuit of FIG. Rc is the resistance of the charging roller 102, Cc is the electrostatic capacity of the charging roller 102, Cd is the electrostatic capacity of the photoreceptor 101, and Cair is the electrostatic capacity of a minute air gap (discharge gap) between the charging roller 102 and the photoreceptor 101. Capacity.
When no discharge occurs, the following relationship is established between the applied AC voltage Vac (amplitude; Vpp) and the charging AC current Iac according to the impedance Zc.
Iac = Iz; Iz = α · Vac, α = 1 / (√2 · Zc) (5)
However, when a discharge is occurring, ie
Vac (Vpp) ≧ 2 × Vth (V) Vth: discharge start voltage (6)
In this case, as shown in the graph of FIG. 12, the above relationship is not satisfied and Iac ≧ Iz (Iz is a broken line portion in the discharge region of FIG. 12). In the description of this example, the difference Idis between Iac and Iz is defined as the discharge current amount.
Since an electrical transient phenomenon is included when discharge is occurring, it is difficult to theoretically obtain the discharge current amount Idis. Furthermore, the discharge current amount Idis is easily influenced by temperature and humidity, contact conditions of the charging roller 102, physical properties, dirt due to a developer, and the like, and is not always constant. Therefore, it is necessary to obtain the discharge current amount Idis for each printing operation or for every predetermined time.
The discharge current amount Idis is calculated by the following equation (1).
Idis = Iac−α · Vac (7)
The proportional constant α is obtained from Iac and Vac in an undischarged state. When the ratio of the current Iac to the peak-to-peak voltage Vpp less than the discharge start voltage Vth × 2 (V) is α, AC current such as current flowing to the contact portion (hereinafter referred to as nip current) other than the current due to discharge is α · Vpp. The difference between Iac measured when a voltage equal to or higher than the discharge start voltage Vth × 2 (V) and this α · Vpp is the discharge current.
In this embodiment, the discharge current amount Idis is controlled to be constant. This control method will be described below.
The discharge current amount Idis changes as the environment and durability are increased when charging is performed under the control of a constant voltage or a constant current. This is because the relationship between Vpp and the discharge current amount Idis and the relationship between the alternating current value and the discharge current amount Idis are fluctuating.
In the AC constant current control method, control is performed by the total current Iac flowing from the charging roller 102 to the photosensitive member 101 to be charged, and in the AC constant voltage control method, control is performed by the AC voltage (Vpp) applied to the charging roller 102. For this reason, the amount of discharge current cannot actually be controlled. For example, due to environmental fluctuations in the material of the charging roller 102, the discharge current amount naturally decreases as the nip current increases, and the discharge current amount increases as the nip current decreases. Therefore, it has been impossible to completely suppress the increase / decrease in the discharge current amount even with the above control method.
In order to obtain a desired discharge current value Idis at all times, the present inventors perform control in the following manner. The image forming apparatus of the present invention has a controller (not shown) and current detection means (not shown). With these and a power source (not shown), one point of AC voltage (Vpp) in the undischarged area and 2 AC voltage in the discharged area during non-image formation (between paper, during rotation before printing, and after printing). Apply more than the point, and measure the total current Iac at that time.
The controller measures the current Iac at a point of AC voltage 0 as an undischarged region (Iac and Idis are 0 at Vpp = 0) and a plurality of AC voltages in the discharge region, and performs an approximation process from each voltage and current value. The applied voltage Vpp corresponding to the desired discharge current Idis is calculated and applied to the charging roller 102 from the power source. In the case of the current control method, instead of the current detection means, Iac in the undischarged area and the discharge area is applied as voltage detection means, and Iac corresponding to the desired Idis is obtained and applied as described above. You can do that.
When image formation is continuously performed, stable Idis can be obtained by performing the above operation between image formations.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these experimental examples, and other means may be used as long as they satisfy the constituent elements of the present invention. good. Further, although not particularly shown, each unit such as a photoconductor that is an image carrier and a cleaning blade may be individually installed in the image forming apparatus main body, or a photoconductor, a charging unit, a developing unit, A cartridge in which two or more of the cleaning means are integrated may be used.

<Example of production of inorganic fine particles>
Aluminum oxide (alumina) can be obtained by a known gas phase oxidation method or a method of firing in a predetermined gas using transition alumina or an alumina raw material that becomes transition alumina by heat treatment. Here, alumina fine particles were prepared by a gas phase oxidation method, the fine particles were observed with an electron microscope (SEM), and the number average primary particle size was measured. The number average primary particle size was 400 [nm]. The particles were mechanically pulverized to obtain alumina fine particles having a particle size of 50 to 300 [nm]. In addition, it can be obtained by the buyer method (wet alkali method) or the like.
In addition, strontium titanate was prepared by washing hydrous titanium oxide obtained by hydrolysis by adding ammonia water to an aqueous titanium tetrachloride solution with pure water, and using the hydrous titanium oxide slurry as SO ₃ for hydrous titanium oxide. 0.26 [%] sulfuric acid was added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.58 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and washing was repeated until the electrical conductivity of the supernatant liquid reached 50 μS / cm. A 0.9-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Further, distilled water was added so as to be 0.6 [mol / liter] in terms of SrTiO ₃ . The slurry was heated to 60 ° C. at 6.7 [° C./hour] in a nitrogen atmosphere, and reacted for 6 hours after reaching 60 [° C.]. After the reaction, the reaction mixture was cooled to room temperature, and the supernatant was removed. Then, washing with pure water was repeated, followed by filtration with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step.
These fine particles were observed with an electron microscope (SEM), and the number average primary particle size was measured. An example of SEM observation is shown in FIG. The fine particles had a cubic or rectangular parallelepiped crystal structure, and the number average primary particle size was 150 [nm].
Strontium titanate with different particle diameters can be obtained by adjusting the pH, the amount of Sr (OH) ₂ .8H ₂ O, the temperature raising conditions, etc., in the above production conditions.
In addition, silica fine particles having an average particle diameter of 50 [nm] were obtained by a known production method.

<Example of image carrier production>
FIG. 14 is a layer configuration model diagram of the photoconductor 101 which is an image carrier in this example. In this photoreceptor 101, a charge generation layer 101d and a charge transport layer 101e are provided in this order as a photosensitive layer on a support 101a. Further, the photoreceptor 101 has a lower wear rate (high mechanical strength) and is on the outermost surface. A surface protective layer 101f is provided. Further, a binder layer 101b and an undercoat layer 101c for the purpose of preventing interference fringes may be provided between the support 101a and the charge generation layer 101d.
The support 101a has a layer in which the support itself has conductivity, such as aluminum, aluminum alloy, or stainless steel, or a layer formed by vacuum deposition of aluminum, aluminum alloy, indium oxide-tin oxide alloy, or the like. Supports and plastics can be used. In addition, a support in which conductive fine particles (for example, carbon black, tin oxide, titanium oxide, and silver particles) are impregnated with plastic or paper together with an appropriate binder resin, a plastic having a conductive binder resin, or the like may be used. it can.
Further, a binder layer (adhesive layer) 101b having a barrier function and an adhesive function can be provided between the support 101a and the photosensitive layers 101d and 101e. The binder layer 101b is used to improve the adhesion of the photosensitive layer, improve the coating property, protect the support, cover defects on the support 101a, improve the charge injection from the support 101a, and protect the photosensitive layer from electrical breakdown. Formed for. The binding layer 101b can be formed of casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, aluminum oxide, or the like. The film thickness of the binding layer 101b is preferably 5 [μm] or less, and particularly preferably 0.1 to 3 [μm].

Examples of the charge generation material used for the charge generation layer 101d include (1) azo pigments such as monoazo, disazo, and trisazo, and (2) phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine. Further, (3) indigo pigments such as indigo and thioindigo, and (4) perylene pigments such as perylene acid anhydride and perylene imide may be mentioned. Further, (5) polycyclic quinone pigments such as anthraquinone and pyrenequinone, and (6) squarylium dye may be mentioned. Further, (7) pyrylium salts and thiapyrylium salts, and (8) triphenylmethane dyes can be mentioned. Further, (9) inorganic substances such as selenium, selenium-tellurium and amorphous silicon, (10) quinacridone pigment, (11) azulenium salt pigment, and (12) cyanine dye are included. Further, (13) xanthene dye, (14) quinoneimine dye, (15) styryl dye, (16) cadmium sulfide, and (17) zinc oxide are exemplified.
Examples of the binder resin used for the charge generation layer 101d include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, and diallyl phthalate resin. In addition, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, and vinyl chloride-vinyl acetate copolymer resin. Can be mentioned. However, it is not limited to these. These can be used alone or as a mixture or as a copolymer polymer.
The solvent used in the charge generation layer coating material is selected from the solubility and dispersion stability of the resin and charge generation material used. As the organic solvent, alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, aromatic compounds, or the like can be used.
The charge generation layer 101d is well dispersed by a method such as a homogenizer, ultrasonic wave, ball mill, sand mill, attritor or roll mill together with the above-mentioned charge generation material 0.3 to 4 times the amount of binder resin and solvent. It is formed by coating and drying. The thickness is preferably 5 [μm] or less, and particularly preferably in the range of 0.01 to 1 [μm].
In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and known charge generating substances can be added to the charge generation layer 101d as necessary.

Examples of the charge transport material used for the charge transport layer 101e include various triarylamine compounds, various hydrazone compounds, various styryl compounds, and various stilbene compounds. In addition, various pyrazoline compounds, various oxazole compounds, various thiazole compounds, various triarylmethane compounds, and the like can be given.
As the binder resin used to form the charge transport layer 101e, an acrylic resin and a styrene resin are preferable. Further, a resin selected from polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, unsaturated resin, and the like is preferable. Particularly preferred resins include polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, polycarbonate resin and diallyl phthalate resin.
The charge transport layer 101e is generally formed by dissolving the charge transport material and the binder resin in a solvent and applying them. The mixing ratio (mass ratio) of the charge transport material and the binder resin is about 2: 1 to 1: 2. As the solvent, ketones such as acetone and methyl ethyl ketone, and esters such as methyl acetate and ethyl acetate are used. In addition, aromatic hydrocarbons such as toluene and xylene, chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride, ethers such as tetrahydrofuran and dioxane, and the like are used.
In applying this solution, for example, a coating method such as a dip coating method, a spray coating method, or a spinner coating method can be used. Drying is preferably 10 ° C. to 200 [° C.], more preferably 20 to 150 [° C.] for 5 minutes to 5 minutes.
Time is preferred, more preferably 10 [min] to 2 [hour], and the drying can be performed under air drying or static drying.
The charge transport layer 101e is electrically connected to the above-described charge generation layer 101d, receives charge carriers injected from the charge generation layer 101d in the presence of an electric field, and transmits these charge carriers to the protective layer 101f. Has the function of transporting to the interface. The charge transport layer 101e has a limit of transporting charge carriers, and thus cannot be made thicker than necessary. .
Furthermore, an antioxidant, a UV absorber, a plasticizer, and a known charge transport material can be added to the charge transport layer 101e as necessary.

Furthermore, the surface protective layer 101f is applied and cured on the charge transport layer 101e to form a photoconductor 101 having a different wear rate.
(1) Method for forming surface protective layer 101f [1]
As the surface protective layer 101f of the electrophotographic photoreceptor satisfying the above conditions, a compound obtained by polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule as shown in the following chemical formula 1 There is a protective layer to contain.

In Chemical Formula 1, A represents a hole transporting group. P ¹ and ^{P 2} represents a chain polymerizable functional group. P ¹ and P ² may be the same or different. Z represents an organic residue which may have a substituent. a, b, and d represent 0 or an integer of 1 or more, and a + b × d represents an integer of 2 or more. When a is 2 or more, P ¹ may be the same or different. When d is 2 or more, P ² may be the same or different. When b is 2 or more, Z and P ² are the same or different. May be.

By polymerizing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule, the compound having a hole transporting ability in the surface protective layer 101f has at least two or more crosslinking points. And incorporated into a three-dimensional crosslinked structure via a covalent bond. The hole transporting compound can be either polymerized alone or mixed with a compound having another chain polymerizable group, and the kind / ratio thereof is arbitrary. As used herein, the compound having another chain polymerizable group includes any monomer, oligomer or polymer having a chain polymerizable group. When the functional group of the hole transporting compound and the functional group of the other chain polymerizable compound are the same group or a group that can be polymerized with each other, they both take a copolymerized three-dimensional crosslinked structure via a covalent bond. Is possible. In the case where both functional groups are functional groups that do not polymerize with each other, the photosensitive layer is a mixture of at least two or more three-dimensional cured products or other chain polymerizable compound monomers in the three-dimensional cured product as a main component. It is comprised as a thing containing the hardened | cured material. It is also possible to form an IPN (Inter Penetrating Network), that is, an interpenetrating network structure by controlling the blending ratio / film forming method well.
The surface protective layer 101f can contain at least one selected from the group consisting of fluorine atom-containing resins, carbon fluorides, and polyolefin resins as a lubricant. The following are mentioned as the preferable compound. However, it is not limited to these compounds.
Preferred examples of the fluorine atom-containing resin include a polymer or copolymer resin of a compound selected from vinyl fluoride, vinylidene fluoride, and chlorotrifluoroethylene, and resin fine particles. In addition, a polymer or copolymer resin and resin fine particles of a compound selected from tetrafluoroethylene, hexafluoropropylene, perfluoropropylene, and perfluoroalkyl vinyl ether may be mentioned. Examples of the carbon fluoride include compounds represented by (CF) n and (C2F) n. Preferable polyolefin-based resins include homopolymer resins such as polyethylene resin, polypropylene resin, and polybutene resin, copolymer resins such as ethylene-propylene copolymer, and ethylene-butene copolymer, and resin powder.
These lubricants can be used alone or in combination of two or more at any ratio. Further, the surface protective layer 101f may contain a dispersant for the lubricant, a dispersion aid, other various additives, a surfactant, and the like.
By including at least one of fluorine atom-containing resin, carbon fluoride, and polyolefin resin as a lubricant in the surface protective layer 101f, the slipperiness and water repellency of the surface of the photoreceptor can be improved. Thereby, the wear and shape change of the surface protective layer 101f can be further suppressed. Further, it is possible to prevent deterioration of transfer characteristics and slipperiness due to chemical deterioration of the surface protective layer 101f due to charging, development, transfer, etc. during repeated use, and further deterioration of electrical characteristics such as sensitivity reduction and potential reduction. Particularly preferable results are obtained when the fluorine-containing resin is used.
The ratio of the lubricant contained in the surface protective layer 101f is preferably 1 to 70 [%], more preferably 5 to 50 [%] with respect to the total weight of the layer to be the surface protective layer 101f. If the amount of the lubricant is more than 70 [%], the mechanical strength of the layer to be the surface protective layer 101f is likely to be lowered. Sometimes.
The surface protective layer 101f containing the cured product of the hole transporting compound having a chain polymerizable group may contain a charge transporting material.
As a method for forming the surface protective layer 101f, a polymerization reaction is generally performed after applying a solution containing the hole transporting compound. It is also possible to form a surface protective layer by reacting a solution containing the hole transporting compound in advance to obtain a cured product and then dispersing or dissolving in a solvent again. As a method for applying these solutions, for example, a dip coating method, a spray coating method, a curtain coating method, and a spin coating method are known. The dip coating method is preferable from the viewpoint of efficiency and productivity.
The hole transporting compound having a chain polymerizable group is preferably polymerized by radiation. The greatest advantage of polymerization by radiation is that a polymerization initiator is not required, which makes it possible to produce a very high-purity three-dimensional photosensitive layer and to ensure good electrophotographic characteristics. In addition, because it is a short and efficient polymerization reaction, it is highly productive, and because of its good radiation transparency, it inhibits curing when a thick film or additives such as additives are present in the film. The influence of is very small. However, depending on the type of the chain polymerizable group and the type of the central skeleton, the polymerization reaction may not easily proceed, and in this case, it is possible to add a polymerization initiator within a range that does not affect the reaction. The radiation used at this time is an electron beam and a γ ray. In the case of electron beam irradiation, any type such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used as an accelerator. When irradiating an electron beam, irradiation conditions are very important in order to develop electrical characteristics and durability. The acceleration voltage is preferably 250 [kV] or less, and optimally 150 [kV] or less. The dose is preferably in the range of 10 to 1000 [kGy]. When the accelerating voltage exceeds the above, the electron beam irradiation damage tends to increase on the characteristics of the photoreceptor. Further, when the dose is less than the above range, the curing tends to be insufficient, and when the dose is large, the photoreceptor characteristics are likely to be deteriorated.

(2) Method for forming surface protective layer 101f [2]
Furthermore, as the surface protective layer 101f, a charge transport material having at least one group selected from the group consisting of a curable phenol resin and a hydroxyalkyl group, a hydroxyalkoxy group, or a hydroxyphenyl group which may have a substituent. There is a surface protective layer containing.
The curable phenol resin, which is a binder resin used for the surface protective layer, is generally a resin obtained by a reaction between phenols and formaldehyde. There are two types of phenolic resins: a resole type obtained by reacting with phenol with an excess of formaldehyde and reacting with an alkali catalyst, and a novolak obtained by reacting with phenol and an excess of phenol with formaldehyde. Divided into molds.
The resol type is also soluble in alcohol and ketone solvents, and is heated to form a cured product by three-dimensional crosslinking polymerization. On the other hand, the novolak type generally does not cure even when heated as it is, but forms a cured product by adding a formaldehyde source such as paraformaldehyde or hexamethylenetetramine and heating. In general, the resol type is used as a varnish for paints, adhesives, cast products and laminated products, and the novolak type is mainly used as a molding material or a binder.
The phenolic resin used as the binder resin can be either the above-mentioned resol type or novolac type, but it should be cured without adding a curing agent, or the resol type should be used because of its operability as a paint. Is preferred. These phenol resins can be used singly or in combination of two or more, and a resol type and a novolac type can also be mixed and used.
For example, the surface protective layer 101f can be formed using a polyhydroxymethylated bisphenol compound having two or more hydroxymethyl groups.
The skeleton of the above-described bisphenol compound has a structure represented by the following chemical formula 2.

In chemical formula 2, X represents a single bond or a divalent linking group. R1 and R2 are each a halogen atom, an aryl group, a vinyl group, an optionally substituted alkyl group, an optionally substituted cyclic alkyl group, or an optionally substituted alkoxy group as a substituent. Represents an aryl group which may have a substituent or a heterocyclic group which may have a substituent.

When this polyhydroxymethylbisphenol compound is subjected to a heat treatment, an ether bond or a further condensation reaction proceeds by a condensation reaction between hydroxymethyl groups to form a methylene bond. Alternatively, a methylene bond is formed by a condensation reaction between the hydroxymethyl group and the ortho-position or para-position hydrogen atom of the phenolic hydroxyl group. When these condensation reactions occur between various molecules, a three-dimensional cured film having a high crosslinking density can be obtained. These condensation reactions are essentially reactions that are not hindered by moisture and oxygen in the air, and proceed sufficiently even in a system to which a charge transport material is added. The crosslinking reaction by heat treatment of the polyhydroxymethyl bisphenol compound has a feature that it is not necessary to add a curing catalyst generally used for thermosetting. Therefore, when such a compound is used as the surface protective layer 101f of the electrophotographic photoreceptor, problems such as an increase in residual potential and a decrease in resistance of the surface protection layer 101f due to the residual curing catalyst do not occur.
In addition, polyhydroxymethyl bisphenol compounds do not require the addition of a curing catalyst, and the hydroxymethyl group itself is sufficiently stable against moisture unlike isocyanates and silicone resins. Are better.
The surface protective layer 101f is formed by coating a photosensitive layer obtained by dissolving or diluting a curable phenolic resin with a solvent or the like on the photosensitive layer, and a polymerization reaction occurs after coating to form a cured layer. The polymerization proceeds by heat addition and condensation reaction, and after coating the surface protective layer, it is heated to cause a polymerization reaction to produce a polymer cured layer.
In addition, the charge transport material having a hydroxyalkyl group, a hydroxyalkoxy group or a hydroxyphenyl group which may have a substituent is preferably a triphenylamine derivative. In addition, examples of the substituent that the hydroxyphenyl group may have include halogen atoms such as fluorine, chlorine, bromine, and iodine, and methyl, ethyl, propyl, and butyl groups that may have a substituent. An alkyl group is mentioned. In addition, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group which may have a substituent, and an aryl group such as a phenyl group, a naphthyl group, an anthryl group and a pyrenyl group which may have a substituent Can be mentioned. Or heterocyclic groups, such as a pyridyl group, a thienyl group, a furyl group, and a quinolyl group which may have a substituent, are mentioned.
Among the charge transport materials, the charge transport material having a hydroxyalkyl group or a hydroxyalkoxy group is preferably a compound having a specific structure represented by the following chemical formula 3.

In Chemical Formula 3, R ₁₁ , R ₁₂ and R ₁₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. α, β, and γ each have a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, and a substituent. Represents a benzene ring which may have one or more heterocyclic groups which may be substituted. a1, b1 and c1 are 1 or 0, and m1 and n1 are 0 or 1.

Further, the charge transport material is uniformly dissolved or dispersed in the coating material for producing the surface protective layer 101f, and is applied. The mixing ratio of the charge transporting material and the curable phenolic resin is preferably a mass ratio of charge transporting material / curable phenolic resin = 0.1 / 10 to 20/10, particularly 0.5 / 10 to 10/10. preferable. If the amount of the charge transport material is too small relative to the curable phenol resin, the effect of lowering the residual potential is reduced, and if it is too much, the strength of the surface protective layer may be weakened.
The surface protective layer 101f is not essentially a resistor, but the charge is transferred by a charge transport material contained in the surface protective layer to maintain the sensitivity of the electrophotographic photosensitive member provided with the surface protective layer. The potential is lowered. Therefore, it is not necessary to set the volume resistivity as a resistor low. By setting the volume resistivity to 1 × 10 ¹² [Ω · cm] or more, the flow of the formed electrostatic latent image is high. Can be suppressed in dimension.
In the electrophotographic photosensitive member having the surface protective layer 101f, the release property of the surface of the electrophotographic photosensitive member can be improved at a higher level by further containing fluorine atom-containing resin fine particles.
As the fluorine atom-containing resin fine particles, ethylene tetrafluoride, ethylene trifluoride chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin and the like are preferable. It is preferable to appropriately select one or two or more of these copolymers. In particular, tetrafluoroethylene resin and vinylidene fluoride resin are preferable. The molecular weight distribution and particle size of the resin particles can be appropriately selected and are not particularly limited.
As a solvent for preparing the coating liquid for the surface protective layer 101f, the polyhydroxymethylbisphenol compound and the charge transporting material are sufficiently dissolved, and further, a lower charge transporting layer or charge that is in contact with the coating liquid for the surface protective layer 101f. A solvent that does not adversely affect the generation layer or the like is preferable.
Accordingly, alcohols such as methanol, ethanol and 2-propanol, ketones such as acetone, cyclohexanone and methyl ethyl ketone, and esters such as methyl acetate and ethyl acetate can be used as the solvent. In addition, ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as toluene and xylene, and halogenated hydrocarbons such as chlorobenzene and dichloromethane can be used. Further, these may be mixed and used. Among these, the most suitable solvents are alcohols such as methanol, ethanol and 2-propanol.
Conventionally, known charge transport materials are generally insoluble or hardly soluble in solvents of alcohols, and uniform dissolution in polyhydroxymethyl bisphenol compounds is difficult. However, when it contains a hydroxy group as a charge transport material, it is soluble in a solvent containing alcohols as a main component and has little influence on the lower layer such as a charge transport layer.
As a method for applying the surface protective layer 101f, general coating methods such as a dip coating method, a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, and a blade coating method can be used. An additive for an antioxidant may be added to the surface protective layer 101f for the purpose of preventing deterioration of the surface protective layer 101f due to adhesion of an active substance such as ozone or NOx generated during charging.

In this example, a total of three types of photoconductors were obtained: a photoconductor on which two types of surface protective layers 101f were formed and a photoconductor on which no surface protective layer was provided.

[Photoreceptor Production Example 1 (Electrophotographic Photoreceptor A)]
An aluminum cylinder (JIS A3003 aluminum alloy) having a length of 260.5 [mm] and a diameter of 60 [mm] was used as the support 101a. On top of this, a 5% by mass methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was applied by an immersion method to form an undercoat layer 101c having a thickness of 0.5 [μm].
Next, the following charge generation layer coating materials (a to c) were dispersed for 1 [hour] by a sand mill using 1 [mmφ] glass beads, and 100 [parts by mass] of methyl ethyl ketone; Is added to the undercoat layer 101c by dip coating, and dried at 90 [deg.] C. for 10 minutes to form a charge generation layer 101d having a thickness of 0.17 [[mu] m]. Formed. a: Crystal of hydroxygallium phthalocyanine having the strongest peak at 28.1 ° in diffraction angle 2θ ± 0.2 in X-ray diffraction of CuKα as a charge generation material 3 [part]
b: Polyvinyl butyral ... 2 [parts]
c: Cyclohexanone: 100 [parts]
Next, the following charge transport layer coating material (d to g) is prepared, and this is dip-coated on the charge generation layer 101d and dried with hot air at 110 ° C. for 1 hour, and the film thickness is 13 μm. The charge transport layer 101e was formed.
d: Charge transport material compound of the following chemical formula 4 ... 7 [parts]

e: Polycarbonate resin (Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) ... 10 [parts]
f: Monochlorobenzene ... 105 [parts]
g: Dichloromethane 35 [parts]

Furthermore, the protective layer 101f was formed in the following manner.
In this example, reversal development is used, and an organic photoreceptor obtained by coating and curing a surface layer containing a compound obtained by polymerizing a hole transporting compound of the following chemical formula 5 by electron beam irradiation as the surface protective layer 101f; did.
40 parts of the hole transporting compound of the following chemical formula 5 are dissolved in 60 parts of n-propyl alcohol.

Further, 10 [parts] of tetrafluoroethylene fine particles were added, and a surface protective layer coating material dispersed with a high-pressure disperser (microfluidizer, manufactured by Microfluidics) was prepared.
After applying this paint on the photoconductors of the four layers 101a + 101c + 101d + 101e, an electron beam is irradiated under the conditions of an acceleration voltage of 150 [KV] and a dose of 40 [kGy] to form a protective layer 101f having a thickness of 3 [μm]. An electrophotographic photoreceptor A was obtained.

[Photoreceptor Production Example 2 (Electrophotographic Photoreceptor B)]
The following surface protective layer coating solution was prepared.
-Surface protective layer coating material a: Tetrakishydroxymethyl-bisphenol in which all the ortho-position hydrogen atoms of the phenolic hydroxyl group of bisphenol represented by the following chemical formula 6 are substituted with a hydroxymethyl group as a curable phenol resin as a binder resin Compound: 100 [parts]

ｂ：下記の化学式７で表される電荷輸送材料・・・７０［部］

b: Charge transport material represented by the following chemical formula 7: 70 [parts]

c: Tetrafluoroethylene fine particles: 42 [parts]
d: Ethanol ... 150 [parts]
And dissolved in a solvent dispersed with a high-pressure disperser (Microfluidizer, manufactured by Microfluidics).
The surface protective layer coating solution is dip-coated on the same 101a + 101c + 101d + 101e photoconductor as in Photoconductor Production Example 1, and dried with hot air at 145 [° C.] for 1 [hour], and the film thickness is 3 [μm]. The layer 101f was provided to obtain an electrophotographic photosensitive member B.
Here, the film thickness of the surface protective layer 101f was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd.).

[Photoreceptor Production Example 3 (Electrophotographic Photoreceptor C)]
An electrophotographic photosensitive member C having the same four-layer structure 101a + 101c + 101d + 101e as that in Photoconductor Production Example 1 and having no surface protective layer was obtained. Instead, the charge transport layer 1e was 16 [μm], and the total film thickness was the same as that of the photoreceptors A and B.
The obtained photoreceptor was subjected to a surface polishing treatment using a wrapping tape as necessary to adjust the surface shape.

<Developer production example>
Non-magnetic toner particles (mass average particle size 5.5 [μm], average circularity 0.918) were obtained by a known production method. To the nonmagnetic toner particles 100 [parts], silica particles having an average particle size of 0.02 [μm] are added 1.2 [parts] and, if necessary, a lubricant or inorganic fine particles are externally added to the toner. (T) was obtained.
As the carrier (C), a carrier for imagePRESS C1 was used and mixed so that the mass ratio of toner (T) / developer (T + C) was 8 [%] to obtain a developer.

<Evaluation equipment>
As an image forming apparatus for evaluation, an image forming apparatus as shown in FIGS. 1 to 4 was prepared.
The evaluation apparatus will be described with reference to FIG.
As shown in FIG. 5, the cleaning blade 107 having a plate shape with a thickness T of 2 [mm] was fixed to a cleaning blade sheet metal (base material) 107B connected to the cleaning blade urging means (spring) 107S. The cleaning blade 107 is brought into contact with the photosensitive member 101 at a contact pressure = 24.5 [N / m] (25 [g / cm]) and a set angle θ = 23 [°]. The cleaning brush 108 is provided with a flicker bar 111 that removes transfer residual toner and the like. The position of the flicker bar 111 may be adjusted according to setting conditions such as direction and position in accordance with the driving direction and speed of the cleaning brush 108.
The cleaning brush 108 is formed in a roll brush shape having a diameter of 16 [mm] by weaving conductive fibers on a base fabric and winding it on a core metal having a diameter of 6 [mm]. An acrylic conductive thread having a thickness of 0.67 [Tex] (6 [denier]) was used as the conductive fiber, and the fiber density was 10 [10,000 / inch ² ] and was implanted into the base fabric with a W weave. A thing is formed in a sheet form, and is wound so as to ensure conductivity with the cored bar. The resistance of the brush was 6 × 10 ³ [Ω · cm]. The contact amount with respect to the photosensitive member 101 is 1 [mm] and the contact width is 7 [mm].
As the photoconductor 101, the photoconductor prepared in the above-described image carrier manufacturing example was used, and it was driven to rotate in the direction of arrow X at a predetermined surface speed.
A charging roller for iRC5185 (manufactured by Canon Inc.) having an effective length (length of the chargeable portion) of 0.32 [m] is used as the charging unit 102, and the latent image formation signal 103 is added to the charging unit 102. Was provided with a laser exposure apparatus of 1200 [dpi]. The bias applied to the charging roller 102 and the latent image forming signal 103 have an absolute value of 600 [V] of the surface potential (Vd) of the photosensitive member 101 at the position of the developing unit 104 when no latent image exposure is performed, and latent image exposure. The absolute value of the irradiation part potential (Vl) is adjusted to 150 [V].
Further, a non-magnetic two-component developing unit as the developing unit 104 and a transfer unit 105 provided with a belt-like intermediate transfer member. The drive conditions and bias conditions of the transfer belt and developing unit were adjusted. These driving speeds and bias conditions to be applied are appropriately adjusted according to the surface speed of the photoconductor 101.

<Example 1>
Using the evaluation apparatus described above, the surface speed of the image carrier (photosensitive member 101) was set to 0.25 [m / sec]. Further, the cleaning brush 108 was adjusted to be driven in the same direction (counterclockwise in the drawing) at the contact portion with the photoconductor 101 at 120 [%] of the surface speed of the photoconductor 101.
The AC bias is adjusted so that the discharge current is 100 [μA], that is, the discharge current Idis per unit length is 0.313 [mA / m]. As the cleaning blade 107, polyurethane rubber having a rubber hardness of 73 °, 100% modulus = 3920 [kN / m ² ] (40 [kgf / cm ² ]), and elongation at break = 420 [%] was used. As the lubricant 109, zinc stearate formed in a rectangular parallelepiped shape was fixed to a sheet metal (not shown), and the sheet metal was brought into contact with the cleaning means 106 with a spring 110 which is an urging member. In addition, a pressure detection means (not shown) is provided so as to contact with a constant pressure. As inorganic fine particles, a toner was prepared by externally adding 0.8 [parts] of strontium titanate having a number average primary particle size of 150 [nm] together with silica particles in the external addition of the developer production examples described above. The photoconductor 101 was the photoconductor A, and the surface shape before evaluation was subjected to surface polishing so that Rzini was 0.3584 [μm].
As for durability, as shown in FIG. 15A, an image having an image ratio of 6 [%] formed by horizontal ruled lines with 300 [μm] lines spaced by 5 [mm] is used as a document, and the normal temperature / normal humidity (23 In an environment of [° C./50[%]; referred to as N / N), A4 paper, 10 [hour / day] was printed intermittently on 2 single-sided sheets, and 100 [k sheets] was printed. Next, in a high temperature / high humidity (30 [° C.] / 80 [%]; referred to as H / H) environment, and further in a low temperature / low humidity (15 [° C.] / 10 [%]; referred to as L / L) environment. In the same manner as in the N / N environment, durability was 100 [k sheets] for a total of 300 [k sheets]. On each durable printing day, the power was completely turned off at night.
In each environment, for the initial printing, the first printing in the morning, and the last printing in the evening, after the evaluation image formation, the following severe operation was performed, and then the evaluation image formation was performed again. In addition, the presence or absence of abnormal noise, vibration (billing), etc. was evaluated.
Severe driving was performed as follows. As shown in FIG. 15B, image formation with an image ratio of 6 [%] localized in the longitudinal direction was performed for 1 [minute] (60 [sheets] in this example). Thereafter, the developing unit and the transfer unit were released, and, except for non-sheet passing, the idling rotation for 1 [min] was performed five times in the normal printing durability state for a total of 5 [min].
The evaluation image is a halftone image with 1 dot and 1 space (denoted as 1D1S), a grid image with an interval of 5 [mm], 1D1S, 1D2S, solid, white, the first half is solid, and the second half is white, and 17 A gradation image and further 1D1S were formed again in this order.
After durability, severe operation evaluation, and image evaluation in each of the above environments, the wear measurement of the edge portion of the cleaning blade and the observation and measurement of the image carrier were performed.
Each evaluation item and evaluation criteria are as follows. ○ is very good, △ is good, or no problem in practical use, x may be the same as conventional, or may be insufficient in characteristics. Each evaluation condition is shown in Tables 1-2, and the evaluation results are shown in Table 3 below. Shown in

<Abnormal noise, vibration>
Evaluated from sound and vibration generated by the image forming apparatus during the above severe operation
◎; Abnormal noise, no vibration
○; There is an abnormal noise during severe driving (sound). No vibration
□; There is an abnormal sound during severe driving (loud sound). No vibration
Δ: Abnormal noise during normal operation (low noise). No vibration
×: Abnormal noise at normal endurance (loud sound) or vibration or dripping of cleaning blade

<Slip through>
Mainly evaluated from visual evaluation of ruled line, two-tone, and half-tone images, and the photoreceptor surface observation results.
◎; No slip on image. The surface of the image carrier is also clean
○: No slipping on the image. There is no toner contamination on the back side of the cleaning blade (on the downstream side in the direction of travel of the photoconductor), so that the surface of the image carrier can be detected by taping.
□; No slipping on the image. There is toner contamination on the back side of the cleaning blade (downstream in the direction of the photoreceptor)
Δ: Seen through the image carrier but not on the image
×; Image slip-through occurred

<Filming and toner fixing>
Evaluation was made from halftone, solid, white, 17-gradation images and the corresponding photoreceptor surface observation results.
A: Neither filming nor toner fixation on the image. The surface of the image carrier is also clean
○: Local deposits are observed on the image carrier, but neither filming nor toner fixation on the image is observed.
□; Local toner adherence is observed on the image carrier, but neither filming nor toner adherence is observed on the image.
Δ: Deposits are observed in the medium to wide range on the image carrier, but there is no filming on the image.
×: Image defect due to filming on the image or toner fixation

<Wearing of the cleaning blade>
◎; DW is 75 [μm ² ] or less
○; DW 75 super 150 [μm ^2] below
□; DW more than 150 225 [μm ² ] or less
Δ: DW is over 225 300 [μm ² ] or less
×; DW is over 300 [μm ² ]

<Wear of photoconductor>
From the measurement of the film thickness of the photoconductor before and after durability, the wear amount [μm / 100 k rotation] per 100 [k rotation] of the photoconductor was calculated. Further, the surface roughness Rzlast [μm] after durability was measured.
In addition, the larger Rzini and Rzlast was displayed as the large Rz as the maximum value of Rz through endurance.

<Example 2>
In contrast to Example 1, the photoconductor 101 was such that the photoconductor A had an Rzini of 0.3213 [μm]. In addition to setting the surface speed of the photosensitive member 101 to 0.50 [m / sec], the spring 110 was changed to increase the pressure at which the lubricant 109 abuts against the cleaning brush 108. In addition, in the external addition of toner production, 1.6 [parts] of strontium titanate having an average particle size of 150 [nm] was externally added to obtain a toner.
Various conditions are shown in Tables 1-2. Table 3 shows the results of durability evaluation similar to that of Example 1.

In each of Examples 1 and 2, there was no problem such as abnormal noise, the chipping of the cleaning blade was very small, and a good image was obtained through durability.

<Examples 3 to 20, Example 74>
An apparatus as shown in FIG. 4 was used as an evaluation apparatus.
The photoconductor 101 is the photoconductor C. In addition, inorganic fine particles referred to in the developer production example were not added in this example, and toner particles were obtained by adding calcium stearate fine particles while changing the addition amount during toner production. Durability evaluation similar to that in Example 1 was performed by varying the surface velocity V and the discharge current Idis of the photoconductor 101.
Various conditions are shown in Tables 4-5. Table 6 shows the results of durability evaluation similar to that of Example 1.

<Comparative Examples 1-8>
An apparatus as shown in FIG. 4 was used as an evaluation apparatus.
As the photoconductor 101, photoconductor B and photoconductor C were used. In addition, inorganic fine particles referred to in the developer production example were not added in this example, and toner particles were obtained by adding calcium stearate fine particles while changing the addition amount during toner production.
Durability evaluation similar to that in Example 1 was performed by varying the surface velocity V and the discharge current Idis of the photoconductor 101. Various conditions are shown in Tables 4-5. Table 6 shows the results of durability evaluation similar to that of Example 1.

The results of Examples 3 to 20, and Example 74 and Comparative Examples 1 to 8 are represented by Idis × V on the horizontal axis.
FIG. 7 and FIG. 8 show the examples in which the lubricant supply amount Mz is taken as the vertical axis, and the examples (evaluation of Δ or more) are marked with “◯” and the comparative examples (x is included in the evaluation results).
From Tables 4-6 and FIGS. 7 and 8,
Mz ≧ Az × Idis × V + Bz (1)
And Mz ≦ 5 (2)
However,
When Idis × V ≦ 0.1, Az = 0.66, Bz = 0.004
When Idis × V> 0.1, Az = 2.72, Bz = −0.202
At that time, good results were obtained.

<Examples 21 to 50>
As an evaluation apparatus, an apparatus having an inorganic fine particle reservoir as shown in FIG. 2 was used. As the lubricant, calcium stearate was externally added in the same manner as in Examples 3 to 20 and Example 74. Alumina particles having an average particle diameter of 400 [nm] held in the agent reservoir 109 ′ as inorganic fine particles were applied to the surface of the photoreceptor 101 using the cleaning brush 109 ′. The application amount was controlled by adjusting the rotation speed of the cleaning brush 109 ′ and the setting conditions of the flicker bar 111.
These were subjected to the same durability evaluation as in Example 1 by varying the surface velocity V and the discharge current Idis of the photoconductor 101. Various conditions are shown in Tables 7-8. Table 9 shows the results of durability evaluation similar to that of Example 1.

From Tables 7 to 9, Examples 23 to 25, Examples 28 to 30, and Examples 33 to 33 in which the supply amount Ms [mg / m ² ] of the inorganic fine particles of the following formula satisfies the range, especially among the inorganic fine particles added. 35, Examples 38 to 40, Examples 43 to 45, and Examples 48 to 50 improved cleaning blade wear and slippage.
Ms ≧ As × Idis × V + Bs (3)
And Ms ≦ 15 (4)
However,
When Idis × V ≦ 0.1, As = 1.00, Bs = 0.100
When Idis × V> 0.1, As = 2.48, Bs = −0.048

Although the detailed mechanism is unknown, it seems that the presence of an appropriate amount of inorganic fine particles may effectively act on the spreading and scraping of the lubricant in the cleaning means. In addition, the inorganic fine particles may be considered to act as a lubricant such as a roller at the contact portion between the cleaning blade 107 and the photosensitive member 101.
Furthermore, the specific gravity of the lubricant zinc stearate and calcium stearate is 1.1 and 0.9, respectively. On the other hand, the specific gravity of strontium titanate, alumina, and silica of the inorganic fine particles is 5.13, 3 to 4, 1.9 to 2.1, respectively, and the specific gravity of the inorganic fine particles is approximately 2 to 6 [ Double]. Due to this difference in specific gravity, it is considered that the inorganic fine particles suitably push the aggregate or coating of the lubricant fine particles, reach the contact portion between the cleaning blade 107 and the photosensitive member 101, and act on scraping.

<Examples 51 to 58>
As an evaluation apparatus, as shown in FIG. 3, an apparatus having a plurality of agent reservoirs and a plurality of cleaning brushes was used. The cleaning brush is obtained by winding a core having a thickness of 5 [mm] around a base metal having a thickness of 0.5 [mm] and a pile having a fiber length of 3 [mm] and a diameter of 12 [ mm] roll brush shape. Inorganic fine particles were held in the agent reservoir 109 ′, and a lubricant was held in the agent reservoir 109, and were applied to the surface of the photoreceptor with the brush. In either case, the application amount was controlled by adjusting the rotation speed of the cleaning brushes 108 and 108 ′ and the setting conditions of the flicker bars 111 and 111 ′.
Each of these was evaluated for durability. Various conditions are shown in Tables 10 to 11, and the evaluation results are shown in Table 12.

From Tables 10 to 12, filming and abnormal noise were reduced by providing the lubricant supply means. Moreover, DW was reduced when zinc stearate was used as the lubricant from comparison between Example 51 and Examples 52 to 58 in Tables 10-12.
Further, in Examples 54 to 58 in which the particle diameter of the inorganic fine particles was 50 [nm] or more and 300 [nm] or less, abnormal noise and slip-through were suppressed. Further, in Example 58 in which the inorganic fine particles were strontium titanate, DW was further reduced.

<Examples 59-66>
As the photoconductor, photoconductor A and photoconductor B were used, and the initial surface shape Rzini was further adjusted in the polishing step. The evaluation machine used the lubricant reservoir 109, which was the lubricant supply means of FIG. 3, in a solid state as shown in FIG. Durability evaluation similar to that of Examples 51 to 58 was performed using the evaluator. For Examples 64-66, some cleaning blades with different rubber properties were used.
Various conditions are shown in Tables 13 to 14, and durability evaluation results are shown in Table 15.

As can be seen from the comparison between Example 58 and Example 59, the use of the lubricant supply means including the solidified lubricant and the brush member is advantageous in reducing the size of the image forming apparatus without any adverse effects on characteristics. Further, the control by the contact pressure of the brush member as described later is possible, which is advantageous for stably supplying the lubricant for a long period of time, and is preferable for maintaining the cleaning property for a long period of time.
Further, in comparison between Example 59 and Example 60 and subsequent examples, Examples in which the wear rate is 0.3 [μm / 100 k rotations] or less have little change in the surface shape Rz of the photoreceptor, and the slipping through and filming are improved. It was.
In particular, in Examples 62 to 66 in which the maximum value “large Rz” of the surface shape is 0.1 to 1.0 [μm] or less, abnormal noise and vibration were further improved. This is probably because the surface shape was suitably maintained, and slipping or abnormal friction was suppressed.

<Examples 67 to 73>
A cleaning blade having different characteristics was used.
The same evaluation machine as Examples 59-66 was used for the evaluation machine. The supply amount of the lubricant was controlled in Examples 67 to 69 by adjusting the rotation speed of the cleaning brush in the same manner as in Examples 59 to 66. Further, in Examples 70 to 73, as in Example 1, the contact pressure between the lubricant and the cleaning brush was adjusted and controlled. At that time, the rotational speed of the cleaning brush was also the same as in Example 1.
The conditions are shown in Tables 16 to 17, and the durability evaluation results are shown in Table 18.

From comparison of the results of Tables 13 to 15 and Examples 67 to 68 of Tables 16 to 18, 2940 ≦ 100% modulus ≦ 5880 [kN / m ² ] (30 ≦ 100% modulus ≦ 60 [kgf / cm ² ]) ) When the elongation at break was 300% or more, the cleaning blade wear DW was further improved.
Further, in Examples 70 to 73 in which the supply of the lubricant was controlled by contact pressure, the slipping through was improved. The reason is not clear, but by adopting the contact pressure control method, the change in coating amount due to deformation (hair fall) of the fibers of the fur brush is suppressed, or the solidified lubricant is also like a flicker bar It is considered that the cleaning brush has a stronger force for rubbing the surface of the photoreceptor.

In Example 73 in which the surface velocity V of the photoreceptor exceeds 0.5 [m / sec], DW slightly increased as compared with Examples 67 to 72.
The above results were evaluated from a different perspective.
An apparatus as shown in FIG. 6 was prepared. The photosensitive member 101 is driven at an arbitrary speed in the direction of arrow X by a driving unit (not shown). A load detection unit 113 holding the cleaning blade 107 is provided vertically above the photoconductor 101 so that the load received by the cleaning blade 107 in the rotation direction of the photoconductor 101, that is, the frictional force can be detected. . The load detecting means 113 has an upper plate on which a weight is placed, and can adjust the pressure with which the cleaning blade 107 abuts on the photosensitive member 101. The load detecting means 113 is further held by a balance-like holding means, and there is a balance weight (not shown) on the opposite side across the fulcrum O, and is held horizontally. In addition, a charging unit 102, a developing unit 104, a cleaning brush 108, a lubricant 109, and an urging unit 110 for adjusting the pressure at which the lubricant 109 abuts against the cleaning brush 108 are arranged.
These are equal in pressure (CLN pressure) at which the cleaning blade 107 contacts the photosensitive member 101 at each speed, a ratio (f / V) between the frequency f and the photosensitive member surface speed V, and a discharge current value Idis to the photosensitive member 101. It has been adjusted to become. With this apparatus, the photoreceptor A was used, and the surface speed V was changed to perform friction evaluation.
FIG. 16 shows the result of plotting the standard deviation of the dynamic friction force against the surface speed V in a steady state after the rotation of the photosensitive member 101 is started.
As shown in FIG. 16, when the photosensitive member surface speed V is 0.5 [m / sec] (500 [mm / sec]) or less, the standard deviation of dynamic friction increases almost linearly with the surface speed of the photosensitive member 101. There is a trend. However, at a high speed exceeding 0.5 [m / sec], the standard deviation of the dynamic friction with respect to the surface speed V sometimes deviates from the speed-dependent linearity.
Accordingly, it is considered that the cleaning blade wear DW of Example 73 exceeding 0.5 [m / sec] slightly increased.
The above-described friction evaluation is not limited to this, and may be measured by installing a strain gauge so that the friction force applied to the cleaning blade 107 can be measured in the image forming apparatus as shown in FIGS.
In Example 72 of 0.08 [m / sec] (80 [mm / sec]), good results were obtained, but 0.1 [m / sec] (100 [mm / sec]) or less. The surface speed of A4 is a low speed machine corresponding to 20 [ppm] or less in A4, and the configuration as in this example may increase the cost.
That is, the surface speed of the photoconductor (image carrier) is preferably 0.1 [m / sec] or more and 0.5 [m / sec] or less.

By using the configuration of the present embodiment of the present embodiment, it is possible to reduce the wear of the cleaning blade, the cleaning failure, and the image defects applied thereto, so that a good image can be obtained in the long term. Further, since the supply amount of the lubricant is controlled in accordance with the discharge current amount and the photoreceptor surface speed, it is possible to prevent an excessive supply or insufficient supply of the lubricant and to stably carry out an appropriate amount of the lubricant from start to finish.
Further, by using both the solidified lubricant and the external supply of inorganic fine particles, it is possible to reduce the size and extend the life of the apparatus and to provide an image forming apparatus that can guarantee a long-term cleaning performance.

101; image carrier 101a; support 101b; binder layer 101c; undercoat layer 101d; charge generation layer 101e; charge transport layer 101f; surface protective layer 102; charging means 103; latent image forming signal 104; developing means 105; Transfer means 106; Cleaning means 107; Cleaning blade 107a; Viewing direction 107b when observing cleaning blade wear; Viewing direction 107B when observing cleaning blade wear; Cleaning blade sheet metal 107S; Cleaning blade urging means 108, 108 ' Cleaning brush 109; lubricant, lubricant reservoir 109 ′; inorganic fine particle reservoir 110; lubricant urging means (spring)
111, 111 ′; Flicker bar 112; Waste toner conveying means 113; Load detecting means X; Example of driving direction of image carrier θ: Setting angle O of cleaning blade to image carrier; Holding of friction force measuring device Supporting point P; transfer material T; cleaning blade thickness W; cleaning blade wear width D; cleaning blade wear depth S1; power supply Cc; charging means capacitance Rc; charging means resistance Cair; Electrostatic capacity Cd; electrostatic capacity Zc of image carrier; impedance between charging means and image carrier

Claims (14)

An image carrier, a charging unit that contacts or approaches the image carrier and is charged with an oscillating voltage, and the latent image formed on the image carrier is visualized with a developer. An image forming apparatus comprising: a developing unit that transfers the developed image onto a recording medium; and a cleaning unit that includes an elastic blade for removing the transfer residual developer from the surface of the image carrier after the transfer. And
A lubricant is supplied to the surface of the image carrier, the supply amount of the lubricant is Mz [mg / m ² ], and the amount of discharge current per unit length in the longitudinal direction flowing from the charging unit to the image carrier is Idis. An image forming apparatus satisfying the following formulas (1) and (2) when [mA / m] and the surface velocity of the image carrier are V [m / sec].
Mz ≧ Az × Idis × V + Bz (1)
Mz ≦ 5 (2)
[However, when Idis × V ≦ 0.1, Az is 0.66 and Bz is 0.004, and when Idis × V> 0.1, Az is 2.72 and Bz is −0. 202. ] Inorganic fine particles are supplied to the surface of the image carrier, the supply amount of the inorganic fine particles is Ms [mg / m ² ], and the discharge current amount per unit length in the longitudinal direction flowing from the charging unit to the image carrier is Idis [ 2. The image forming apparatus according to claim 1, wherein the following formulas (3) and (4) are satisfied when the surface velocity of the image carrier is V [m / sec]: mA / m]. .
Ms ≧ As × Idis × V + Bs (3)
Ms ≦ 15 (4)
[However, when Idis × V ≦ 0.1, As is 1.00 and Bs is 0.100, and when Idis × V> 0.1, As is 2.48 and Bs is −0. 048. ] The image forming apparatus according to claim 1, wherein the lubricant is a fatty acid metal salt. The image forming apparatus according to claim 3, wherein the fatty acid metal salt is zinc stearate. 5. The image forming apparatus according to claim 2, wherein the number average primary particle size of the inorganic fine particles is 50 [nm] or more and 300 [nm] or less. The ratio value of the specific gravity of the inorganic fine particles to the specific gravity of the lubricant ([specific gravity of inorganic fine particles] / [specific gravity of lubricant]) is 2 or more and 5 or less, wherein: The image forming apparatus according to any one of the above. The image forming apparatus according to claim 1, wherein the wear rate of the image carrier is 0.3 [μm / 100 k rotations] or less. 8. The image forming apparatus according to claim 1, wherein Rz on the surface of the image bearing member is 0.1 [μm] or more and 1.0 [μm] or less. 100% modulus of an elastic member constituting the elastic blade is 2940 [kN / m ² ] or more and 5880 [kN / m ² ] or less, and elongation at break is 300 [%] or more. Item 9. The image forming apparatus according to any one of Items 1 to 8. The lubricant supply means for supplying the lubricant is provided downstream of the transfer means and upstream of an elastic blade provided in the cleaning means in the rotation direction of the image carrier. 10. The image forming apparatus according to any one of items 1 to 9. The image forming apparatus according to claim 10, wherein the lubricant supply unit is a lubricant supply unit including a solidified lubricant and a rotatable brush-like member. The image forming apparatus according to claim 11, wherein a contact pressure between the lubricant and the brush-like member is variable. The image forming apparatus according to claim 2, wherein the supply unit of the inorganic fine particles is a developing unit. 14. The image formation according to claim 1, wherein the surface speed of the image carrier is 0.1 [m / sec] or more and 0.5 [m / sec] or less. apparatus.

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