JP2006337416A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge capable of high-quality image formation and having superior durability. <P>SOLUTION: In the image forming apparatus which is equipped with a photoreceptor 2Y, having surface free energy of ≥45 mN/m and in which an image is formed with a toner as a developer, a lubricating material 62Y can be supplied, such that when an image is formed, the average of surface free energy of an image formation area of the photoreceptor 2Y becomes ≤32 mN/m, and the difference between the two extreme values of surface free energy becomes ≤5 mN/m. The process cartridge is used in the image forming apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a process cartridge used for a copying machine, a printer, a facsimile, or a complex machine thereof. In particular, charging, writing, development, transfer, cleaning, static elimination, etc. are repeated to sequentially form toner images on the photoreceptor, and the toner images are sequentially transferred to form images on transfer sheets such as paper and OHP films. The present invention relates to an electrophotographic image forming apparatus and a process cartridge.

With the development and popularization of PCs (personal computers), the demand for higher image quality in color image formation in electrophotographic apparatuses has become very strong. For example, materials that capture color images from digital cameras and scanners are very commonly used, and it has become common for the plot area of graphs to be halftone colors.
In addition, it has become common to form images taken with digital cameras not only with silver halide photographs but also with sublimation printers and inkjet printers. However, these image formations require a long time for image formation, and the cost of paper and ink for image formation is high, and producing posters and presentation materials has problems in terms of production speed and cost. there were.
Image formation using an electrophotographic process is excellent in terms of production speed and cost, but it has been necessary to further improve image quality. In image formation using an electrophotographic process, to improve the image quality, it is sufficient to reduce the toner particle diameter. However, as the toner particle diameter decreases, the residual toner on the photosensitive member by the cleaning blade decreases. The cleaning could not be performed sufficiently and the image quality was greatly deteriorated. As the particle size of the toner decreases, the amount of charge per toner mass increases, so the electrostatic adhesion between the photoreceptor and toner increases. The cleaning blade scrapes off the toner on the photosensitive member. However, the toner with a small particle size is relatively small compared to the case where the toner is caught by the cleaning blade, and the force to scrape off the toner is small. become weak. In addition, when the cleaning blade vibrates due to the friction between the cleaning blade and the photoconductor, the toner enters a slight gap generated between the cleaning blade and the photoconductor, and the toner passes through the cleaning blade, greatly reducing the image quality. It was a cause. If there is a large amount of toner slipping due to such cleaning failure, streaky abnormal images may be formed, or the slipped toner may adhere to the charging roller, causing uneven resistance of the charging roller, and whitening due to uneven charging potential. In many cases, streaks were generated, and the toner component adhered to the photosensitive member in a streak form to generate white streaks.

In order to reduce the adhesion between the photoconductor and the toner, it is effective to reduce the surface free energy of the photoconductor. For example, Patent Document 1 (Japanese Patent Laid-Open No. 10-69100) discloses a photoconductor having a surface free energy of 30 dyne / cm or less by using a binder containing a fluororesin. However, an image of an image forming apparatus using this photoconductor can form a high-quality image without much image formation. However, as the image formation is repeated, the surface free energy of the photoconductor increases. As a result, the image quality deteriorates.
In Patent Document 2 (Japanese Patent Laid-Open No. 2001-66812), a photoconductor having a surface layer of fluorine-containing amorphous silicon is used, the surface free energy of the photoconductor is set to 40 mN / m or less, and image formation is repeated. An image forming apparatus is disclosed in which a substance that causes image flow adhering to the surface of a photoreceptor is removed by a cleaning unit. However, since the surface layer of amorphous silicon containing fluorine is formed by a vapor phase method, the cost of the photoreceptor is very high. Further, there is no disclosure of residual toner cleaning properties when a small particle size toner is used. In general, defective cleaning of residual toner does not occur on the entire surface of the image forming area, but tends to concentrate on a limited place, which is caused by variations in the shape of the cleaning blade and the surface free energy of the photoreceptor. It is. For this reason, it is not preferable that the surface free energy of the photoreceptor is measured only at one point on the photoreceptor.
Patent Document 3 (Japanese Patent Laid-Open No. 2001-272809) discloses that a photoreceptor having a siloxane resin layer has a surface free energy of 40 to 80 mN / m, an average particle diameter of toner of 4 to 12 μm, and an average charge amount of 10 to An image forming apparatus with 30 μC / g is disclosed. However, the toner used in this image forming apparatus is set to have a low average charge amount in order to weaken the adhesion to the photoreceptor. For this reason, the stability of the image is lower than that in the case of using normal toner, and soiling is likely to occur depending on the environment, which is not preferable.
In Patent Document 4 (Japanese Patent Laid-Open No. 11-311875), a photoconductor having a surface free energy of 3 to 65 mN / m is used, and image formation with an increase in photoconductor surface free energy due to durability of 25 mN / m is formed. An apparatus is disclosed. In the measurement of the surface free energy disclosed in Patent Document 4, water, methylene iodide, and α-bromonaphthalene are used. However, an error in calculating the surface free energy occurs with only three types of solvents. The error cannot be verified. In particular, water tends to cause measurement errors, and it is difficult to measure true surface free energy. Further, as described above, it is not preferable that the surface free energy of the photoreceptor is measured only at one point on the photoreceptor. If the image to be formed by the user is completely random, one point may be measured. However, a user who creates many images such as quotations and proposals, such as a standard table, has a free surface on the photoreceptor. It is easy to generate an energy distribution, and it is easier to have a distribution in the longitudinal direction of the photoconductor than a distribution in the circumferential direction of the photoconductor. It is not preferable to have a surface free energy distribution in the longitudinal direction of the photoconductor, which is liable to cause a reduction in image quality due to a decrease in cleaning properties.
Patent Document 4 also discloses an image forming apparatus using an inexpensive organic photoreceptor as the photoreceptor. However, in an image forming apparatus using an organic photoreceptor, the organic photoreceptor is easily worn by friction with a cleaning blade. Therefore, in order to achieve a certain life, the photoreceptor film is expected in anticipation of the wear of the photoreceptor. The thickness must be increased. In this case, since the film thickness of the photoconductor in the initial stage of image formation and that over time are greatly different, the electrostatic capacity of the photoconductor is greatly different and it is difficult to make the image density constant. Patent Document 4 also discloses an image forming apparatus using a photoreceptor in which a surface layer containing a fluorine compound is provided on an organic photoreceptor. However, since the wear rate of the surface layer containing a fluorine compound is not much slower than that of a normal organic photoreceptor, the surface layer needs to have a considerable thickness. However, if the surface layer is made too thick, the movement of holes is hindered, so that the post-exposure potential and the residual potential are likely to increase, making it difficult to use in a high-quality image forming apparatus.
For the purpose of improving the wear resistance of an inexpensive organic photoreceptor, Patent Document 5 (Japanese Patent Laid-Open No. 1-170951) discloses an organic photosensitive material in which a filler such as a metal oxide is contained in the photoreceptor surface layer. The body is disclosed. This organic photoreceptor has a very high wear resistance with respect to the cleaning blade, which is preferable. However, this organic photoconductor increases the surface free energy of the photoconductor, repeats image formation, decreases the transfer efficiency, tends to cause abnormal images such as voids, and wears a cleaning blade to perform cleaning. It had the defect that it was easy to generate a defect.
In Patent Document 6 (Japanese Patent No. 2859646) and Patent Document 7 (Japanese Patent Laid-Open No. 2002-229241), when a lubricant is externally added to a toner and the toner is developed on the photoreceptor by image formation, A technique is disclosed in which a lubricating substance adheres from a toner to a photoconductor to reduce the surface free energy of the photoconductor. This technique is very preferable because it can reduce the friction between the photosensitive member and the cleaning blade and ensure the cleaning performance of the remaining toner. However, since the lubricating material is supplied only to the place where the toner is developed on the photoreceptor, the surface of the place where the toner is not developed for the user who creates many images such as a standard table such as an estimate or a plan. Since the free energy remains high, the surface free energy variation of the photoreceptor tends to be very large. If the place where the surface free energy is high and the place where the surface free energy is in contact with each other with a boundary, the cleaning blade is likely to vibrate at the boundary, and a cleaning failure and an irritating frictional sound are likely to occur.

JP-A-10-69100 JP 2001-66812 A JP 2001-272809 A Japanese Patent Laid-Open No. 11-311875 JP-A-1-170951 Japanese Patent No. 2859646 JP 2002-229241 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus and a process cartridge that can form a high-quality image and have excellent durability.

  As a result of detailed studies to solve the above problems, the present inventors have found that inexpensive organic photoreceptors have high surface free energy, and as such, there are many problems in terms of toner cleaning properties and durability. However, the surface free energy on the surface of the photoreceptor can be reduced by forming an image while applying a lubricating substance to the photoreceptor. However, since organic photoconductors inherently have high surface free energy, it is very important not only to reduce the surface free energy of the photoconductor, but also to reduce variations in the surface free energy of the photoconductor surface. And found the present invention.

The invention according to claim 1 is an image forming apparatus that includes a photoconductor having a surface free energy of 45 mN / m or more, and forms an image using toner as a developer. When the image is formed, the image of the photoconductor is formed. The lubrication substance can be supplied to the photoconductor so that the average of the surface free energy of the formation region is 32 mN / m or less and the difference between the maximum value and the minimum value of the surface free energy is 5 mN / m or less. An image forming apparatus characterized by the above.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the surface free energy of the photoconductor during image formation is measured for each of the regions divided into a plurality of directions in a direction perpendicular to the rotation direction of the photoconductor. The image forming apparatus is characterized in that the width of the plurality of divided regions is 50 mm or less.
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the lubricating material is supplied to the photoconductor after cleaning the residual toner on the photoconductor. .
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the diameter of the photoconductor is 35 to 100 mm.
A fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the lubricating substance is a metal soap.
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the method for measuring the surface free energy of the photoconductor includes the surface of the photoconductor and each component of the surface free energy. This is a method of measuring the contact angle with a known liquid and measuring the surface free energy of the solid using the following formula 7 based on the extended Fowkes theory. The surface free energy is obtained by linear regression from the contact angle data with four or more liquids. An image forming apparatus characterized in that

(However, in the formula, gamma _L is, .Ganma represents the surface free energy of the liquid represented by ^{_{γ a L + γ b L +}} γ C L a L is, .Ganma ^b representing the dispersive component of the surface free energy of the liquid _L represents a dipole component of the surface free energy of the liquid, γ ^C _L represents a hydrogen bond component of the surface free energy of the liquid, γ ^a _S represents ^a dispersed component of the surface free energy of the solid, γ ^b _(S represents the dipole component of the surface free energy of the solid, γ ^C _S represents the hydrogen bond component of the surface free energy of the solid, and θ represents the contact angle.)
According to a seventh aspect of the present invention, in the image forming apparatus according to the sixth aspect, the liquid for measuring the contact angle for obtaining the surface free energy of the photoreceptor is selected from diiodomethane, α-bromonaphthalene, diethylene glycol, glycerin and formamide. An image forming apparatus.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the average particle size of the toner used is 7 μm or less.
According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the maximum resolution at which an image can be formed by the image forming apparatus is 1000 dpi or more.
A tenth aspect of the present invention is the image forming apparatus according to any one of the first to ninth aspects, wherein the image forming apparatus is capable of forming a color image.
An eleventh aspect of the invention is a process cartridge that can be attached to and detached from the image forming apparatus main body according to any one of the first to tenth aspects, wherein the process cartridge has a surface free energy of 45 mN / m or more. When the image is formed, the average surface free energy of the image forming area of the photoconductor is 32 mN / m or less, and the difference between the maximum value and the minimum value of the surface free energy is 5 mN / m or less. The process cartridge is configured such that a lubricating substance can be supplied to the photosensitive member.

According to the first aspect of the present invention, since the surface free energy on the surface of the photoconductor during image formation is low and the variation thereof is small, it is possible to form a high-quality image without generating an abnormal image due to poor cleaning. An image forming apparatus having excellent durability can be provided.
According to the invention of claim 2, since the surface free energy of each region of the photosensitive member can be managed, high quality image formation is possible without generating abnormal images due to poor cleaning, and image formation with excellent durability is achieved. An apparatus can be provided.
According to the invention of claim 3, since the surface free energy of each region of the photoreceptor can be reduced and the variation can be controlled to be small, high-quality image formation is possible without generating an abnormal image due to poor cleaning. Thus, an image forming apparatus with excellent durability can be provided.
According to the invention of claim 4, since the cleaning residual toner is not mixed at the time of applying the lubricating material, the surface free energy can be reduced and the variation thereof can be controlled to be small, so that an abnormal image due to poor cleaning is not generated. Therefore, it is possible to provide an image forming apparatus capable of forming a high quality image and having excellent durability.
According to the invention of claim 5, since the surface free energy of each region of the photosensitive member can be easily reduced and the variation thereof can be controlled to be small, high-quality image formation can be achieved without generating an abnormal image due to poor cleaning. Therefore, an image forming apparatus having excellent durability can be provided.
According to the inventions of claims 6 to 7, since the surface free energy of the photoreceptor can be accurately obtained, high quality image formation is possible without generating an abnormal image due to poor cleaning, An image forming apparatus with excellent durability can be provided.
According to the invention of claim 8, it is possible to provide an image forming apparatus capable of forming a high-quality image even when a small particle size toner capable of forming a high-definition and high-quality image is used.
According to the ninth aspect of the present invention, it is possible to provide an image forming apparatus capable of forming a high-resolution and high-quality image without generating an abnormal image.
According to the invention of claim 10, it is possible to provide an image forming apparatus capable of forming a high-quality color image without generating an abnormal image.
According to the eleventh aspect of the present invention, it is possible to provide a process cartridge that can form a high-quality image and has excellent durability without generating an abnormal image due to poor cleaning.

Hereinafter, the present invention will be described in more detail.
First, a method for measuring surface free energy in the present invention will be described.
As for surface free energy, Ninoaki Kitasaki, Toshio Hata et al. Described the nonpolar intermolecular force regarding surface free energy (synonymous with surface tension) in Journal of Japan Adhesion Association 8 (3), 131-141 (1972). In addition to Fowkes' theory, it states that it can be extended to polar or hydrogen-bonded intermolecular forces. By this extended Fowkes theory, the surface free energy of each substance can be obtained with three components.
This theory is based on the following three assumptions.
<Assumption 1>
The surface free energy of organic materials is expressed as the sum of three different components.

γ ^a : dispersion component (nonpolar wetting)
γ ^b : Dipole component (wetting due to polarity)
γ ^c : hydrogen bonding component (wetting by hydrogen bonding)
<Assumption 2>
Each surface free energy that decreases as a result of contact of two substances can be expressed as the sum of the geometric mean of the corresponding surface free energies, and if there is no corresponding component, there is no interaction between the components. Think.

<Assumption 3>
Standard substances are classified into the following three types.
TYPE ^(A) γ = γ a type: Liquid saturated hydrocarbons and solids.
TYPE (B) γ = γ ^a + γ ^b type: liquids and solids other than (A) and (C).
TYPE (C) γ = γ ^a + γ ^b + γ type: Liquids and solids that are soluble in water or have low interfacial tension with water and have hydrogen bonds.
Based on these assumptions, the surface free energy can be obtained as follows.
If the bonding energy of substances 1 and 2 is W ₁₂ ,

And from equation (2)

It becomes.
When the substance is a solid and a liquid, and the droplet reaches the equilibrium while maintaining the contact angle θ on the solid surface as shown in FIG. 8, the following Young's formula is established.

  Therefore, the following relationship is established between the contact angle and the adhesion energy from the equations (3) and (5).

  From equations (4) and (6)

It becomes.
Using Equation (7), first, the contact angle is measured using Type A liquid, γ _S ^a is obtained from Equation (7), and then the contact angle is measured using Type B liquid to obtain γ _S ^b . At this time, γ _S ^a and γ _S ^b may be obtained from simultaneous data of two types of Type B liquid. Finally, each component of the solid surface free energy can be obtained by measuring the contact angle with a Type C liquid and obtaining γ _S ^c . Further, each component of the surface free energy of the solid can also be obtained from the data of three types of liquids in which γ _L ^b or γ _L ^c is not 0 for all liquids, using a ternary simultaneous equation.
However, when trying to obtain each component of the surface free energy of the solid by the above method, the square root (√γ _S ^b or the like) of each component of the surface free energy may become negative due to the calculation. For example, when √γ _S ^b becomes negative, it is calculated by assuming that γ _S ^b = 0 without calculating γ _S ^b by squaring. The method of obtaining from the contact angle data of three types of liquids is that the solid surface free energy obtained by the combination of the liquids used for the measurement varies greatly, and it is not known which combination of liquids the measurement result should be reliable. was there. In addition, the contact angle is affected by the surface shape of the sample and changes its value. In some cases, the accurate surface free energy may not be measured. However, the conventional method cannot measure the exact surface free energy. Even if it was difficult to judge it. In particular, when water is used for three types of liquids, such problems are likely to occur, and surface free energy is calculated for calculation, but it is not known whether the calculated value is a true value. It was.
In the extended Fowkes theory (7),

After all,

It becomes. Therefore, each component (a, b, c) of the surface free energy of the solid can be obtained by linear regression from the contact angle data (y; x ₁ , x ₂ , x ₃ ) by the standard substance. In the conventional method of obtaining from three types of liquid contact angle data, three unknowns are obtained from three equations. For this reason, if the contact angle of one liquid greatly deviates from the true value due to some influence, the obtained surface free energy of the solid is greatly affected. In the method of obtaining from four or more types of contact angle data in the present invention, the influence of deviation from the true value of the contact angle can be averaged, and the influence of the contact angle measurement error on the surface free energy measurement result can be reduced.
Moreover, when calculating | requiring by linear regression, R-2 power value (multiple correlation coefficient) can be calculated. If the R-square value is close to 1, all contact angle data are in the theoretical formula (7), and it can be determined that the obtained surface free energy of the solid is reliable. In other words, the reliability of measurement can be easily determined from the R-square value. As a criterion for judgment, the measurement result is considered reliable when the R-squared value is 0.8 or more. If it is judged that the R-2 power value is small and the reliability is low, it is considered that the contact angle cannot be measured accurately. In many cases, the cause is the surface shape of the sample, and it is necessary to devise a sample form that reduces the surface roughness and voids. Sample preparation methods with less surface roughness and voids include compression molding and heat melting.
The calculation method by linear regression is as follows.
Assuming that there are contact angle data for n types (n ≧ 3) of liquid, write as follows.

  If the error is ε,

  Sum of squares of this error

(A, b, c) is determined so that is minimized. The minimum requirement is

And when calculated, from (12)

  From (13)

  From (14)

It becomes. (A, b, c) can be obtained by solving the ternary simultaneous equations (15) to (17).
The surface free energy of the solid can be obtained by squaring the obtained (a, b, c).
However, at this time, any of a, b, and c may be negative. Since a, b, and c are the square roots of the surface free energy of a solid, it is physically strange that this is negative. Therefore, the above calculation must be solved under the conditions of a ≧ 0, b ≧ 0, c ≧ 0.
Since S (a, b, c) is quadratic with respect to a, b, c, if any of a, b, c becomes negative, for example, if c becomes negative, c = It is sufficient to obtain (a, b) so that S (a, b, 0) is minimized by setting 0. Here, when b becomes negative, b = 0 is set, and a is obtained so that S (a, 0,0) is minimized. However, even if c becomes negative, S may be smaller if (a, c) is determined so that b = 0 and S (a, 0, c) is minimized. Therefore, in actuality, if any of a, b, c is negative, a = 0, b = 0, c = 0, a = b = 0, a = c = 0, b = c = 0 A solution to be obtained is calculated by calculating a ≧ 0, b ≧ 0, c ≧ 0 and S being minimum.
The R-squared value can be obtained by the following formula.

  When S is the minimum from (11) and (18), the R-squared value is the maximum.

The standard substance used in the measurement method of the present invention may be a combination in which each component of surface free energy is four or more types of known liquids and γ _L ^b or γ _L ^c does not become zero in all liquids. Liquids with known components of surface free energy need not cause extended wetting. Extended wetting is a phenomenon in which wetting spreads spontaneously when a droplet is placed on a solid. In this case, the contact angle cannot be measured. TypeA liquids cause extended wetting for many organic substances.
As a combination of standard substances for measuring the surface free energy of an organic substance, a combination containing two or more Type B liquids and two or more Type C liquids without using a Type A liquid is desirable. In the surface free energy measurement, the value obtained depends on the combination of liquids used for the measurement, but the combination including two or more Type B liquids and two or more Type C liquids shows almost the same value and the measurement is stable.
As the solvent used for measuring the surface free energy on the surface of the photoreceptor in the image forming apparatus of the present invention, for example, the solvents shown in Japan Adhesion Association Paper 8 (3), 131-141 (1972) can be used. , Diiodomethane, α-bromonaphthalene, diethylene glycol, glycerin, and formamide are preferable because the surface free energy of the surface of the photoreceptor with high reliability can be obtained.

  In the image forming apparatus of the present invention, an inexpensive organic photoreceptor having a surface free energy of 45 mN / m or more is preferably used as the photoreceptor. As described above, a photoconductor having a surface free energy of 45 mN / m or more has a large frictional force with the cleaning blade, so that the photoconductor and the cleaning blade are easily worn. Therefore, by forming an image while applying a lubricating material to the photoreceptor, the surface free energy on the surface of the photoreceptor can be reduced, and the frictional force between the photoreceptor and the cleaning blade can be reduced. However, the surface free energy of the photoreceptor used in the present invention is essentially 45 mN / m or more, preferably 47 mN / m or more, and more preferably 48 to 55 mN / m. If there is a site where the chemical substance is decomposed or removed, a large difference in surface free energy is generated between the site where the lubricating substance is present and cleaning failure or noise is likely to occur. Therefore, it is necessary to control the surface free energy distribution of the photoreceptor. In the image forming apparatus of the present invention, the average surface free energy of the photoreceptor during image formation is 32 mN / m or less, preferably 30 mN / m or less, more preferably 10 to 28 mN / m. If the average surface free energy of the photoconductor during image formation exceeds 32 mN / m, the frictional force between the photoconductor and the cleaning blade increases, and the photoconductor and the cleaning blade are likely to wear. This is not preferable because it is likely to cause cleaning failure and abnormal noise. Even if the average surface free energy is 32 mN / m or less, if there is a distribution of surface free energy, cleaning defects and abnormal noise are likely to occur, and as the surface free energy decreases, the variation in surface free energy becomes a problem. . In the image forming apparatus of the present invention, the difference between the maximum value and the minimum value of the surface free energy on the surface of the photoreceptor during image formation is 5 mN / m or less, preferably 4 mN / m or less, more preferably 3 mN / m or less. .

In the image forming apparatus of the present invention, there is basically little unevenness in the surface free energy in the rotation direction of the photoreceptor. For this reason, when measuring with four or more kinds of solvents by a preferable method for measuring surface free energy, it is preferable to measure the contact angle with four or more kinds of solvents along the circumferential direction of the photoreceptor.
The area when determining the surface free energy distribution on the surface of the photoreceptor of the present invention is performed for each of a plurality of divided areas in a direction orthogonal to the rotation direction of the photoreceptor, and the width of the divided areas is 50 mm or less, Preferably it is 30 mm or less, More preferably, it is 5-25 mm. If the width of the plurality of divided regions exceeds 50 mm, it is not preferable because there is a high possibility that there are a plurality of locations where variations in surface free energy exceeding 5 mN / m exist in the region.

The image forming apparatus of the present invention forms an image while applying a lubricating substance on the photoreceptor in order to reduce the surface free energy on the surface of the photoreceptor. In the present invention, it is preferable to supply the lubricating material to the surface of the photoreceptor by using a toner externally added with the lubricating material. Apart from this, an apparatus for supplying a lubricating substance may be used. In this case, the supply (application) of the lubricating substance is performed between the transfer and the charging without affecting the image formation in the electrophotographic process of charging → exposure → development → transfer → cleaning. When the lubricating material is applied from the transfer to the cleaning, the cleaning blade can also function to press and extend the lubricating material onto the photoreceptor. However, since the transfer residual toner stays in the vicinity of the cleaning blade, the applied lubricating substance adheres to the transfer residual toner at a very high rate. There is a high possibility that the surface free energy of the body cannot be controlled. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. 2005-18047, it is very preferable to apply a lubricating substance after cleaning because the surface free energy can be controlled with a small amount of the lubricating substance.
In cleaning, it is preferable to remove the transfer residual toner as much as possible. In addition to the removal by the cleaning blade, the combined use of the fur brush and the magnetic brush, or the cleaning device combining the fur brush and the suction removal device removes the transfer residual toner. It can be completely cleaned and the surface free energy control of the photoreceptor can be suitably performed.

Lubricating materials used in the image forming apparatus of the present invention include fluororesins such as polytetrafluoroethylene and polyvinylidene fluoride, metal soaps such as zinc stearate, aluminum stearate, lead stearate, magnesium stearate, and zinc oleate. Soap that has a small effect on the surface of the photoconductor and has a large effect of reducing the surface free energy of the photoconductor is preferable. Economic, safety of substances generated by decomposition due to charging, etc., and influence on the photoconductor In view of the above, zinc stearate is most preferable.
When using a device that supplies a lubricating substance, the lubricating substance has the effect of reducing the surface free energy of the photoreceptor even if it is simply applied on the photoreceptor, but it is pressed against the surface of the photoreceptor to form a thin film. It is very preferable to make it adhere, because the surface free energy can be reduced and the variation of the surface free energy can be reduced.

  The toner used in the image forming apparatus of the present invention can ensure excellent image quality regardless of the average particle diameter, but it is particularly 7 μm or less, preferably 6 μm or less. Since abnormal images due to poor cleaning can be suppressed, image formation with high image quality can be realized.

  In the image forming apparatus of the present invention, high-quality image formation can be performed regardless of the highest resolution that can form an image, but in particular, high-resolution image formation of 1000 dpi or more, preferably 1200 dpi or more. In this case, high quality image formation becomes possible and the effect is high.

Hereinafter, an embodiment in which the present invention is applied to a color laser printer (hereinafter referred to as “printer”) which is a so-called tandem type image forming apparatus in which a plurality of photosensitive drums as latent image carriers are arranged in parallel will be described. This embodiment is referred to as “Embodiment 1”). The first embodiment is an example in which an apparatus for supplying a lubricating material is used to supply the lubricating material to the surface of the photoreceptor.
FIG. 2 is a schematic configuration diagram of the printer according to the first embodiment.
This printer includes four sets of image forming units 1Y, 1M, 1C, and 1K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). Needless to say, Y, M, C, and K appended to the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black (the same applies hereinafter). In addition to the image forming units 1Y, 1M, 1C, and 1K, an optical writing unit 10 as a latent image forming unit, an intermediate transfer unit 11, a secondary transfer bias roller 18, a registration roller pair 19, a paper feed cassette 20, a belt A fixing type fixing unit 21 and the like are arranged. The optical writing unit 10 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates a surface of a photosensitive drum (to be described later) with laser light based on image information.

FIG. 1 is an enlarged view showing a schematic configuration of an image forming unit 1Y for yellow among the image forming units 1Y, 1M, 1C, and 1K.
The image forming unit 1Y includes a photosensitive drum 2Y as a latent image carrier as a surface moving member, a charger 30Y as a uniform charging unit, a developing unit 40Y as a developing unit, a drum cleaning device 50Y as a cleaning unit, A lubricating substance supply device 60Y, a recycled toner transport device 70Y as toner recycling means, and the like are included. Since the other image forming units 1M, 1C, and 1K have the same configuration, their descriptions are omitted.
The charger 30Y is configured to uniformly charge the surface portion of the photosensitive drum 2Y by bringing a charging roller 31Y as a charging member into contact with or in close proximity to the surface portion. In the first embodiment, a DC voltage is applied to the charging roller 31Y from a DC power source (not shown). However, an AC voltage superimposed on the charging roller 31Y may be applied. However, as in the first embodiment, the configuration in which only the DC voltage is applied to the charging roller 31Y to perform uniform charging significantly suppresses stress on the photosensitive drum 2Y as compared with the case where the AC voltage is superimposed. This is very advantageous in that the life of the photosensitive drum 2Y can be extended. In the first embodiment, a so-called contact charging method using the charging roller 31Y is employed, but a non-contact charging method using a corona charger or the like may be employed. However, the direct charging method as in the first embodiment is advantageous in that the charging unevenness is smaller than that of the non-contact charging method and there is no problem of generation of ozone.
Further, the charger 30Y is provided with a brush roller 33Y for removing foreign matter adhering to the charging roller 31Y from the charging roller 31Y. Note that another cleaning member may be provided instead of the brush roller 33Y.
After the uniform charging process is performed in this manner, the surface of the photosensitive drum 2Y is irradiated with the laser beam modulated and deflected by the optical writing unit 10 while being scanned. Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum 2Y. The formed electrostatic latent image is developed by the developing device 40Y to become a Y toner image. The developing device 40Y includes a developing roll 42Y disposed so as to expose a part of the peripheral surface from the opening of the developing case 41Y. Further, it also includes a first transport screw 43Y, a second transport screw 44Y, a doctor blade 45Y, a toner concentration sensor 46Y, and the like.

The developing case 41Y contains a two-component developer (not shown) containing a magnetic carrier and negatively chargeable Y toner. The two-component developer is frictionally charged while being agitated and conveyed by the first conveying screw 43Y and the second conveying screw 44Y, and then carried on the surface of the developing roll 42Y. Then, after the layer thickness is regulated by the doctor blade 45Y, the layer is conveyed to a developing region facing the photosensitive drum 2Y, where Y toner is attached to the electrostatic latent image on the photosensitive drum 2Y. By this adhesion, a Y toner image is formed on the photosensitive drum 2Y. The two-component developer that has consumed Y toner by development is returned to the developing case 41Y as the developing roll 42Y rotates.
A partition wall 47Y is provided between the first transport screw 43Y and the second transport screw 44Y. The partition wall 47Y separates the first supply unit that accommodates the developing roll 42Y, the first conveyance screw 43Y, and the like and the second supply unit that accommodates the second conveyance screw 44Y in the development case 41Y. The first transport screw 43Y is rotationally driven by a driving unit (not shown), and supplies the two-component developer in the first supply unit to the developing roll 42Y while transporting from the back side to the front side in the drawing. The two-component developer conveyed to the vicinity of the end of the first supply unit by the first conveyance screw 43Y enters the second supply unit through an opening (not shown) provided in the partition wall 47Y. In the second supply section, the second transport screw 44Y is driven to rotate by a driving means (not shown), and transports the two-component developer sent from the first supply section in the direction opposite to that of the first transport screw 43Y. . The two-component developer transported to the vicinity of the end of the second supply unit by the second transport screw 44Y returns to the first supply unit through the other opening (not shown) provided in the partition wall 47Y. .

  The Y toner image formed on the Y photosensitive drum 2Y in this way is primarily transferred to an intermediate transfer belt described later. Residual toner remaining without being primarily transferred adheres to the surface portion of the photosensitive drum 2Y after the primary transfer, and this is cleaned by the drum cleaning device 50Y. The drum cleaning device 50Y brings the cleaning blade 51Y into contact with the surface of the photosensitive drum 2Y, and scrapes and collects transfer residual toner that is unnecessary toner adhering to the surface portion. In the first embodiment, a blade cleaning method for scraping off transfer residual toner by the cleaning blade 51Y is adopted. However, instead of this method or in addition to this method, other methods such as a brush cleaning method such as a fur brush are used. The cleaning method may be adopted. The interior of the drum cleaning device 50Y is a sealed space by the casing 52Y and the photosensitive drum 2Y, and the collected transfer residual toner is not scattered inside the printer.

Further, inside the drum cleaning device 50Y, a transport screw 53Y is provided for transporting the transfer residual toner collected by the cleaning blade 51Y to the front side in the figure. The transfer residual toner conveyed by the conveying screw 53Y is sent into the recycled toner conveying device 70Y. Then, the recycled toner conveying device 70Y conveys the transfer residual toner to the developing device 40Y. The discharge port of the recycled toner conveying device 70Y is opened on the front side in the drawing of the second supply unit of the developing device 40Y. Therefore, the transfer residual toner collected by the drum cleaning device 50Y is returned into the developing device 40Y by the recycled toner conveying device 70Y. Then, after being stirred and transported again by the second transport screw 44Y and the first transport screw 43Y of the developing device 40Y, it is reused for development.
The surface of the photosensitive drum 2Y cleaned by the drum cleaning device 50Y is supplied with a lubricating material by the lubricating material supply device 60Y. The configuration and operation of the lubricating substance supply device 60Y will be described later. The surface portion of the photosensitive drum 2Y supplied with the lubricating substance is again uniformly charged by the charger 30Y, and the above-described image forming process is repeated.

  The color toner images respectively formed on the photosensitive drums 2Y, 2M, 2C, and 2K in the image forming units 1Y, 1M, 1C, and 1K described above are formed on the intermediate transfer belt 12 as an intermediate transfer member of the intermediate transfer unit 11. Primary transfer. As shown in FIG. 2, in addition to the intermediate transfer belt 12, the intermediate transfer unit 11 includes a driving roller 13, stretching rollers 14 and 15, a belt cleaning device 16, and four primary transfer bias rollers 17Y, 17M, and 17C. , 17K, etc. are also provided. The intermediate transfer belt 12 is endlessly moved counterclockwise in the figure by a driving roller 13 that is rotated by a driving system (not shown) while being stretched by a driving roller 13 and stretching rollers 14 and 15. The four primary transfer bias rollers 17Y, 17M, 17C, and 17K are each applied with a primary transfer bias from a power source (not shown). Then, the intermediate transfer belt 12 is pressed from the back surface thereof toward the photosensitive drums 2Y, 2M, 2C, and 2K to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photosensitive drum and the primary transfer bias roller due to the influence of the primary transfer bias. The Y toner image formed on the Y photosensitive drum 2Y is primarily transferred onto the intermediate transfer belt 12 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M toner image, the C toner image, and the K toner image formed on the photosensitive drums 2M, 2C, and 2K are sequentially superimposed and primarily transferred. By such superposition transfer, a four-color superposed toner image is formed on the intermediate transfer belt 12. This four-color superimposed toner image is secondarily transferred onto a transfer sheet P as a recording material at a secondary transfer nip described later. On the other hand, the transfer residual toner remaining on the surface of the intermediate transfer belt 12 after passing through the secondary transfer nip is cleaned by the belt cleaning device 16 in contact with the intermediate transfer belt portion backed up by the stretching roller 15.

The drive roller 13 of the intermediate transfer unit 11 is in contact with the secondary transfer bias roller 18 via the intermediate transfer belt 12 to form a secondary transfer nip. A secondary transfer bias is applied to the secondary transfer bias roller 18 by a power source (not shown). Also, below the optical writing unit 10, a paper feed cassette 20 that accommodates a plurality of transfer papers P in a stack of transfer papers P is disposed. 20a is pressed. When the paper feed roller 20a is driven to rotate at a predetermined timing, the uppermost transfer paper P is fed to the paper transport path. The transfer paper P fed from the paper feed cassette 20 to the paper transport path is sandwiched between the rollers of the registration roller pair 19. On the other hand, the four-color superimposed toner image formed on the intermediate transfer belt 12 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 19 sends out the transfer paper P sandwiched between the rollers at a timing at which the transfer paper P can be brought into close contact with the four-color superimposed toner image at the secondary transfer nip. As a result, the four-color superimposed toner image comes into close contact with the transfer paper P at the secondary transfer nip. Then, it is secondarily transferred onto the transfer paper P under the influence of the secondary transfer bias and nip pressure described above, and forms a full color image combined with the white color of the transfer paper P. The transfer paper P on which the full color image is formed in this way is sent to the fixing unit 21.
The fixing unit 21 includes a belt unit 21b that moves the fixing belt 21a endlessly while being stretched by three rollers, and a heating roller 21c having a heat source therein. Then, the transfer paper P is sandwiched between the belt unit 21b and the heating roller 21c, and the full color image is fixed on the surface thereof. The transfer paper P that has passed through the fixing unit 21 is discharged out of the apparatus through a pair of paper discharge rollers 22.

Next, the configuration and operation of the lubricating substance supply device 60Y will be described. The lubrication substance supply devices 60M, 60C, and 60K provided in the other image forming units 1M, 1C, and 1K have the same configuration, and thus description thereof is omitted.
As shown in FIG. 1, in the lubricating substance supply device 60Y, a fine powdery lubricating substance 62Y is accommodated in the internal space (closed space) of the casing 61Y. The lubricating substance 62Y is for reducing the coefficient of friction between the surface of the photosensitive drum 2Y and the cleaning blade 51Y contacting the surface or a substance such as Y toner or magnetic carrier. In addition, an agitator 63Y, which is a lubricating substance supply member for supplying the lubricating substance 62Y to the surface of the photosensitive drum 2Y, is provided in the casing 61Y of the lubricating substance supply apparatus 60Y. The agitator 63Y has a structure in which two blade members attached to a rotation shaft extending parallel to the drum shaft of the photosensitive drum 2Y rotate. When the agitator 63Y rotates, the lubricating material 62Y is blown toward the surface of the photosensitive drum 2Y by the blade member, and the lubricating material 62Y adheres to the surface of the photosensitive drum 2Y.
The casing 61Y of the lubricating substance supply device 60Y in Embodiment 1 has an integral structure with the casing 52Y of the drum cleaning device 50Y and the casing 32Y of the charger 30Y. The lubricating substance supply device 60Y, the drum cleaning device 50Y, and the charger 30Y are configured as a process cartridge that is integrated with the photosensitive drum 2Y and is detachable from the printer body. On the other hand, the internal space of each casing 32Y, 52Y, 61Y is partitioned from each other by the respective casing portion or cleaning blade 51Y, and the lubricating substance supply device 60Y is provided outside the drum cleaning device 50Y.
The casing 61Y of the lubricating substance supply device 60Y according to the first embodiment includes a portion that is integrated with the other casings 32Y and 52Y, and a cleaning blade 51Y. The casing 61Y is opened only on the side facing the surface of the photosensitive drum 2Y. Of the opening edge of the casing 61Y, the cleaning blade 51Y constituting the upstream side portion of the surface direction of the photosensitive drum 2Y is in contact with the surface of the photosensitive drum 2Y over the entire axial direction of the photosensitive drum 2Y. On the other hand, at the opening edge of the downstream portion, the seal member 64Y provided in the casing portion is in contact with the surface of the photosensitive drum 2Y over the entire axial direction of the photosensitive drum 2Y. On the other hand, a sealing member (not shown) provided in the casing portion also contacts the surface of the photosensitive drum 2Y over the surface movement direction of the photosensitive drum 2Y at the opening edge of the portion located at the axial end of the photosensitive drum 2Y. is doing. That is, in the first embodiment, the opening edge portion of the casing 61Y in the lubricating substance supply device 60Y is in contact with the surface of the photosensitive drum 2Y over the entire area. Therefore, the internal space surrounded by the inner wall surface of the casing 61Y and the surface portion of the photosensitive drum 2Y is a closed space shielded from the outside. In Embodiment 1, as described above, when the agitator 63Y rotates, the lubricating substance 62Y is supplied and adhered to the surface of the photosensitive drum 2Y in the closed space. Thereafter, the lubricating material 62Y adhering to the surface of the photoreceptor drum 2Y passes through the contact portion between the seal member 64Y and the surface of the photoreceptor drum 2Y as the surface of the photoreceptor drum 2Y moves.

By attaching the lubricating substance 62Y to the surface of the photosensitive drum 2Y, mechanical stress applied to the photosensitive drum 2Y during the above-described image forming process can be greatly reduced. That is, mechanical stress such as rubbing by the developer in the developing region and scraping by the cleaning blade can be greatly reduced. As a result, there is an effect that the life of the photosensitive drum 2Y can be extended. This effect is particularly effective when the photosensitive drum 2Y is integrally configured as a process cartridge together with other devices as in the first embodiment. That is, in general, the photosensitive drum has the shortest lifetime among the devices included in the process cartridge, and therefore, the replacement frequency of the process cartridge is determined by the lifetime of the photosensitive drum 2Y. Therefore, extending the life of the photosensitive drum 2Y brings about an effect that the replacement frequency of the process cartridge can be reduced. As a result, it is possible to effectively use other devices that have been exchanged together with the photosensitive drum 2Y before the end of their lifespan, and to improve user convenience.
Further, by attaching the lubricating substance 62Y to the surface of the photosensitive drum 2Y, the mechanical adhesion between the surface of the photosensitive drum 2Y and the toner is weakened. As a result, the transfer efficiency can be improved and the image quality can be improved. The effect of improvement and reduction of transfer residual toner is also obtained.
Moreover, according to the first embodiment, the lubricating substance 62Y is supplied to the surface of the photosensitive drum 2Y in the closed space. Therefore, a part of the lubricating substance to be supplied to the photosensitive drum 2Y is not scattered inside the printer, and all the lubricating substance 62Y not supplied to the photosensitive drum 2Y remains in the closed space. Further, since the lubricating substance supply device 60Y is provided outside the drum cleaning device 50Y, a part of the lubricating substance 62Y to be supplied to the photosensitive drum 2Y is supplied to the photosensitive drum 2Y. In addition, there is no case where the drum cleaning device 50Y is directly collected. Further, in the first embodiment, among the lubricating material 62Y that is blown toward the photosensitive drum 2Y by the agitator 63Y, the lubricant that has not been supplied to the photosensitive drum 2Y falls into the casing 61Y and is again exposed to the photosensitive material. This contributes to the supply to the body drum 2Y. Therefore, according to the first embodiment, all of the lubricating substance 62Y accommodated in the casing 61Y can be used for supply to the photosensitive drum 2Y without waste. Further, since the lubricating substance supply device 60Y is arranged on the downstream side of the drum cleaning device 50Y, it is not affected by the amount of residual toner transferred to the drum cleaning device 50Y, so that it is stable on the latent image carrier. Thus, a lubricating substance can be supplied. Further, the lubricating substance supply device 60Y is disposed on the downstream side of the drum cleaning device 50Y and on the upstream side of the charger 30Y, so that the surface portion of the photosensitive drum 20Y passing through the charger 30Y is disposed on the surface portion. Since the lubricating substance is stably applied, the adhesion of the lubricating substance to the charger 30Y can be reduced.

  Further, in the first exemplary embodiment, the recycle toner transport device 70Y can return the transfer residual toner collected by the drum cleaning device 50Y to the developing device 40Y and be reused. In the conventional image forming apparatus configured to collect the toner by the brush roller and supply the lubricating substance in the drum cleaning device, a lot of the lubricating substance is mixed in the collected transfer residual toner. In general, it is known that a general lubricating substance typified by zinc stearate or the like adversely affects the triboelectric charging of a toner. Specifically, when the zinc stearate (lubricating substance) is mixed with the negatively chargeable toner as in the first exemplary embodiment, the charge amount of the entire toner is reduced (shifted toward the positive side). If the amount of the lubricating substance mixed in becomes too large, the toner charge amount is insufficient, and so-called background contamination occurs. Therefore, in the conventional image forming apparatus, it is extremely difficult to reuse the transfer residual toner collected by the drum cleaning device while suppressing background stains. On the other hand, in the first embodiment, as described above, the lubricating substance supply device 60Y is provided outside the drum cleaning device 50Y, so that the lubricating substance is transferred from the lubricating substance supply device 60Y to the drum cleaning device 50Y. 62Y does not enter directly. Moreover, in the first embodiment, the lubricating substance supply position of the lubricating substance supply apparatus 60Y is closer to the downstream side in the moving direction of the photosensitive drum surface than the cleaning position of the drum cleaning apparatus 50Y (contact position of the cleaning blade 51Y). Is the position. Therefore, the lubricating substance 62Y attached to the surface of the photosensitive drum 2Y reaches the cleaning position of the drum cleaning device 50Y through the charging area, the developing area, and the primary transfer area as the surface of the photosensitive drum 2Y moves. To do. A part of the lubricating material 62Y on the photosensitive drum 2Y is collected by the charging roller 31Y in the charging area, is collected in the developing device 40Y in the development area, and is transferred to the intermediate transfer belt 12 in the primary transfer area. Collected. Therefore, the amount of the lubricating material 62Y on the photosensitive drum 2Y supplied by the lubricating material supply device 60Y decreases before reaching the cleaning position. Therefore, compared with the conventional image forming apparatus, the amount of the lubricating substance 62Y mixed in the transfer residual toner collected by the drum cleaning device 50Y is very small. As a result, according to the first embodiment, even if the image forming apparatus includes a mechanism for supplying the lubricant 62Y that adversely affects the frictional charging of the toner to the photosensitive drum 2Y, the occurrence of background stains is sufficiently caused. It is possible to employ a mechanism for reusing the transfer residual toner collected by the drum cleaning device 50Y while suppressing it.

In the first embodiment, the lubricating substance supply position of the lubricating substance supply apparatus 60Y is further downstream than the cleaning position of the drum cleaning apparatus 50Y in the moving direction of the photosensitive drum surface, and more than the developing area (toner adhesion position). It is upstream. Therefore, the toner hardly enters the lubricating substance supply device 60Y. When the toner is mixed in the lubricating substance supply device 60Y, the toner is mixed with the lubricating substance 62Y, so that the charge amount is reduced as described above. When image formation is performed in a state in which such toner adheres to the surface of the photosensitive drum 2Y together with the lubricating substance 62Y, so-called background contamination occurs. In the first embodiment, as described above, since the toner hardly mixes in the lubricating substance supply device 60Y, the occurrence of such background stains can be prevented.
The configuration for positioning the lubricating substance supply position of the lubricating substance supply apparatus in this way is not limited to the case where the lubricating substance supply apparatus 60Y is provided outside the drum cleaning apparatus 50Y, and the internal space of the casing 61Y. Even if it is not a closed space shielded from the outside, it is an effective configuration.

  In the first embodiment, the seal member 64Y provided at the opening edge of the casing at the downstream side portion in the surface movement direction of the photosensitive drum 2Y contacts the surface of the photosensitive drum over the entire axial direction of the photosensitive drum 2Y. ing. The seal member 64Y is made of urethane rubber, which is an elastic body, and its contact pressure is substantially uniform in a direction orthogonal to the surface movement direction of the photosensitive drum 2Y. With such a configuration, even if the amount of the lubricating material 62Y supplied by the agitator 63Y is non-uniform on the surface of the photosensitive drum 2Y, the lubricating material on the surface of the photosensitive drum is transferred to the seal member 64Y. As it passes through the contact position, it is stretched thinly and evenly and leveled. As a result, a substantially uniform amount of lubricating substance can be adhered to the entire surface of the photosensitive drum. In addition, by appropriately adjusting the contact pressure, the contact angle, and the like of the seal member 64Y, it is possible to prevent an unnecessarily large amount of lubricating substance from adhering to the surface of the photosensitive drum. Therefore, it is possible to minimize the amount of the lubricating substance that enters the drum cleaning device 50Y while maintaining the effect of the lubricating substance 62Y, such as suppressing the wear of the photosensitive drum surface and the cleaning blade 51Y. Therefore, it is possible to further suppress the occurrence of background stains when reusing the transfer residual toner. In addition, since it is possible to minimize the amount of the lubricating material consumed per image formation, the amount of the lubricating material to be loaded in the printer in advance can be reduced, and the size of the apparatus can be reduced. Can also be promoted. In the first embodiment, the block-shaped seal member 64Y is employed, but other shapes such as a flat plate-shaped seal member may be employed.

[Modification]
Next, a modified example of the lubricating substance supply device in the first embodiment will be described. FIG. 3 is an enlarged view showing a schematic configuration of a yellow image forming unit in the present modification, as in FIG.
The lubricating substance supply device 1Y according to the present modified example is configured to supply the lubricating substance to the surface of the photosensitive drum 2Y by rotating the brush roller 363Y that is a lubricating substance supply member, as described in the first embodiment. This has the same configuration as the lubricating substance supply device 60Y. In the lubricating substance supply device 360Y of the present modification, a solid lubricating substance 362Y solidified as a lubricating substance is used. Then, the solid lubricating material 362Y is shaved by the brush roller 363Y. As a result, the lubricating material in the form of fine powder adheres to the brush roller 363Y. Then, when the adhering lubricating substance is conveyed to a region facing the surface of the photosensitive drum 2Y as the brush roller 363Y rotates, the lubricating substance is supplied to the surface of the photosensitive drum 2Y.
Similarly to the lubricating substance supply device 60Y of the first embodiment, the lubricating substance supply device 1Y of the present modified example is also provided outside the drum cleaning device 50Y. Also, the configuration of the casing 61Y has its internal space. Is a closed space shielded from the outside. Therefore, the same effect as the lubricating substance supply device 60Y of the first embodiment as described above can be obtained.

[Embodiment 2]
Next, an embodiment in which the present invention is applied to a printer that is a tandem image forming apparatus as in the first embodiment (hereinafter, this embodiment is referred to as “second embodiment”) will be described. Since the basic configuration of the printer in the second embodiment is the same as that in the first embodiment, the same reference numerals are given to the same components as those in the first embodiment, and only different portions will be described below.
FIG. 4 is a schematic configuration diagram illustrating a main part of the printer according to the second embodiment. This printer employs a tandem system as in the first embodiment, but the image forming units 1Y, 1M, 1C, and 1K are arranged above the intermediate transfer belt 12 in the vertical direction. The printer also includes a transfer paper transport belt 118 as a recording material transport member stretched around the secondary transfer bias roller 18, and the fixing unit 121 employs a roller fixing system. Further, in the printer of the second embodiment, in addition to the lubricating substance supply devices 160Y, 160M, 160C, and 160K that supply the lubricating substance to the photosensitive drum, as in the first embodiment, the intermediate transfer belt is lubricated. A lubricating substance supply device 260 for supplying the substance is also provided.

  FIG. 5 is a schematic configuration diagram showing a lubricating substance supply device 160Y that supplies a lubricating substance to the photosensitive drum 2Y. Note that the lubrication substance supply devices 160M, 160C, and 160K provided in the other image forming units 1M, 1C, and 1K have the same configuration, and thus description thereof is omitted. This lubricating substance supply device 160Y is arranged vertically above the surface of the photosensitive drum 2Y to which a lubricating substance is to be supplied, and the internal space (closed space) of the casing 161Y has the above-described embodiment. 1, a fine powdery lubricating substance 62Y is accommodated. As shown in FIG. 4, the casing 161Y of the lubricating substance supply device 160Y according to the second embodiment has an integrated structure with the casings of the charger 30Y, the developing device 40Y, and the drum cleaning device 50Y. The lubricating substance supply device 160Y, the charger 30Y, the developing device 40Y, and the drum cleaning device 50Y are configured as a process cartridge that is integrated with the photosensitive drum 2Y and is detachable from the printer main body. On the other hand, the internal space of each casing is partitioned from each other, and the lubricating substance supply device 160Y is provided outside the drum cleaning device 50Y.

  The casing 161Y of the lubricating substance supply device 160Y according to the second exemplary embodiment includes a portion that is integrated with the casings of the charger 30Y and the developer 40Y, and seal members 164Y and 165Y as shown in FIG. Yes. The casing 161Y is opened only on the side facing the surface of the photosensitive drum 2Y. Of the opening edge portion of the casing 161Y, the upstream side seal member 165Y and the downstream side seal member 164Y constituting the upstream side portion and the downstream side portion in the surface movement direction of the photosensitive drum 2Y are respectively the shafts of the photosensitive drum 2Y. It is in contact with the surface of the photosensitive drum 2Y over the entire direction. Note that, at the opening edge of the portion located at the axial end of the photosensitive drum 2Y, a seal member (not shown) is placed on the surface of the photosensitive drum 2Y over the surface movement direction of the photosensitive drum 2Y, as in the first embodiment. In contact. That is, also in the second embodiment, the opening edge portion of the casing 161Y in the lubricating substance supply device 160Y is in contact with the surface of the photosensitive drum 2Y over the entire area. The internal space is a closed space shielded from the outside.

  Further, the lubricating substance supply device 160Y of Embodiment 2 is configured such that the lubricating substance 62Y in the internal space moves toward the surface of the photosensitive drum 2Y along the inner wall surface of the casing 161Y by gravity. Has been. Specifically, the inner wall surface of the casing 161Y is configured to always incline downward in the vertical direction toward the surface of the photosensitive drum 2Y at any position except the ceiling surface. Here, as shown in FIG. 6, if there is a portion on the inner wall surface of the casing 161′Y that is inclined upward in the vertical direction toward the surface of the photosensitive drum 2Y, the lubricating substance 62Y stays in that portion. Therefore, the retained lubricating material 62Y cannot be supplied to the surface of the photosensitive drum 2Y. On the other hand, in the configuration of the second embodiment, the lubricating substance 62Y does not stay, and the lubricating substance 62Y accommodated in the casing 161Y is caused by gravity as the lubricating substance is consumed. All of them can move toward the surface of the photosensitive drum 2Y. Therefore, the lubricant substance 62Y does not remain in the casing 161Y, and the lubricant substance 62Y can be used up without remaining. In the configuration in which the lubricating substance in the internal space moves toward the surface of the photosensitive drum along the inner wall surface of the casing by gravity, the lubricating substance supply device 160Y is not provided outside the drum cleaning device 50Y. Moreover, even if the internal space of the casing 161Y is not a closed space shielded from the outside, this is an effective configuration.

FIG. 7 is a schematic configuration diagram showing a lubricating substance supply device 260 for supplying a lubricating substance to the intermediate transfer belt 12.
The lubricating substance supply device 260 is disposed substantially horizontally with respect to the surface of the intermediate transfer belt 12 that is a surface moving member to which a lubricating substance is supplied. In the internal space (closed space) of the casing 261, the solid lubricating material 262 biased by a spring 267 as a biasing means and both the solid lubricating material and the surface of the intermediate transfer belt 12 are rubbed. And a brush roller 266 that is a brush-like rotator that rotates in a rotating manner. In the lubricating material supply device 260, when the brush roller 266 rotates, the solid lubricating material 262 is scraped by the friction of the brush roller 266, and the fine powdery lubricating material adheres to the brush roller 266. Supplied to the surface of the intermediate transfer belt 12. The lubricating substance supply device 260 is provided outside the belt cleaning device 16 in the same manner as the lubricating substance supply device 160Y for the photoreceptor drum 2Y described above, and the configuration of the casing 261 is also an internal space. Is a closed space shielded from the outside.

  Unlike the above-described lubricating material supply device 160Y for the photosensitive drum 2Y, the lubricating material supply device 260 has a vertical direction toward the inner wall surface of the casing 261 toward the surface of the intermediate transfer belt 12, as shown in FIG. There is a portion A inclined upward. Therefore, when the brush roller 266 scrapes the solid lubricating material 262 or when the brush roller 266 rubs the surface of the intermediate transfer belt 12, the powdery lubricating material scattered by the surface of the intermediate transfer belt 12 due to gravity. Cannot move toward the area A, and may stay around the portion A. That is, part of the scattered powdery lubricating substance stays on the inner wall surface portion located at the lowest position in the vertical direction in the casing 261 unless the brush roller 261 rubs. Since the powdery lubricating substance staying in this way cannot be supplied to the surface of the intermediate transfer belt 12, the lubricating substance in the casing 261 cannot be used up completely. However, the lubrication substance supply device 260 uses the brush roller 266 for the inner wall surface portion of the casing 261 in which the powdery lubricant material stays, that is, the inner wall surface portion of the casing located at the lowest position in the vertical direction in this configuration. Is configured to rub. Therefore, even if the powdery lubricating substance stays on the inner wall surface portion, the powdery lubricating substance is recovered by the brush roller 266 and supplied to the surface of the intermediate transfer belt 12. Therefore, the lubricating substance does not remain in the casing 261, and the lubricating substance can be used up without remaining. The configuration in which the brush roller rubs the inner wall surface of the casing in which the powdery lubricating substance stays in the inner space can be used even if the lubricating substance supply device 260 is not provided outside the belt cleaning device 16. Even if the internal space of the casing 261 is not a closed space shielded from the outside, the configuration is effective.

Note that, as in the lubricant substance supply device 160Y for the photoreceptor drum 2Y in the second embodiment, the lubricant substance 62Y in the inner space is directed toward the surface of the photoreceptor drum 2Y along the inner wall surface of the casing 161Y by gravity. The structure that moves in this manner is not limited to the fine powdery lubricating substance, and even when applied to a liquid lubricating substance, the above-described effects can be exhibited. Further, this configuration is applied to a configuration in which a powdery lubricating material scraped from the solid lubricating material 262 by the brush roller 266 is supplied by the brush roller as in the lubricating material supply device 260 for the intermediate transfer belt 12. However, the above-described effects can be exhibited.
In the second embodiment, the lubricant material supply position of the lubricant material supply device 160Y for the photosensitive drum is moved from the surface of the photosensitive drum more than the uniform charging position of the charger 30Y (contact position of the charging roller 31Y). It is on the downstream side. If the amount of the lubricating substance 62Y attached to the charging roller 31Y is large, the amount of current flowing from the charging roller 31Y to the photosensitive drum 2Y decreases, and charging failure may occur. In the second embodiment, as described above, the lubricating substance 62Y is supplied downstream of the uniform charging position of the charger 30Y in the moving direction of the photosensitive drum surface. As a result, the lubricating substance 62Y adhering to the surface of the photoreceptor drum 2Y passes through the development area, the primary transfer area, and the cleaning area as the surface of the photoreceptor drum 2Y moves, and the uniform charging position of the charger 30Y. To reach.
A part of the lubricating material 62Y on the photosensitive drum 2Y is collected in the developing device 40Y in the development area, is collected on the intermediate transfer belt 12 in the primary transfer area, and is also transferred to the cleaning blade 51Y in the cleaning area. To be recovered. Therefore, the amount of the lubricating material 62Y on the photosensitive drum 2Y supplied by the lubricating material supply device 160Y decreases before reaching the uniform charging position.
Therefore, the amount of the lubricating substance 62Y adhering to the charging roller 31Y can be suppressed to be very small, and the occurrence of charging failure can be suppressed. In addition, when a non-contact charging method using a corona charger or the like is adopted, there is almost no problem of charging failure due to a lubricating material. However, as described above, the direct charging method is more suitable for the non-contact charging method. Compared to the above, there is less charging unevenness and there are no problems such as generation of ozone. If the lubricating substance supply position as in the second embodiment is used, it is possible to suppress the occurrence of charging failure as described above. As a result, compared to the non-contact charging method, the structure supplying the lubricating substance 62Y is used. An advantageous contact charging method can be employed. Note that the configuration for positioning the lubricating substance supply position of the lubricating substance supply apparatus in this way is not limited to the case where the lubricating substance supply apparatus 160Y is provided outside the drum cleaning apparatus 50Y, and the internal space of the casing 161Y. Even if it is not a closed space shielded from the outside, it is an effective configuration.

  In the first and second embodiments described above, the lubricating substance supply devices 60Y and 160Y are configured as a process cartridge that is integrated with the photosensitive drum 2Y and the like as a process cartridge that can be attached to and detached from the printer body. Only the substance supply devices 60Y and 160Y may be configured to be detachable from the printer main body. If comprised in this way, the replacement | exchange time of lubricating substance supply apparatus 60Y, 160Y can be set irrespective of the lifetime of the photoreceptor drum 2Y. As a result, the amount of the lubricating material to be mounted is reduced to reduce the size of the lubricating material supply devices 60Y and 160Y, thereby reducing the size of the device, or the amount of the lubricating material to be mounted is increased to supply the lubricating material. The degree of freedom in design can be increased, for example, by increasing the dimensions of the devices 60Y and 160Y and reducing the frequency of replacement of the lubrication substance supply device. Note that the configuration in which only the lubricating substance supply device is detachable from the printer main body as a single unit can be used even if the lubricating substance supply devices 60Y and 160Y are not provided outside the drum cleaning device 50Y, and the casing 61Y. 161Y is effective even if the internal space is not a closed space shielded from the outside.

  As described above, in the printers of the first embodiment (including the above-described modification) and the second embodiment, the transfer residual toner that is unnecessary toner attached to the surface of the photosensitive drum 2Y as the surface moving member or the intermediate transfer belt 12 is used. A drum cleaning device 50Y and a belt cleaning device 16 are provided. In addition, lubricity is supplied to the surface of the photosensitive drum 2Y and the like by supplying a lubricating substance for reducing the coefficient of friction between the surface and the substance (toner, magnetic carrier, cleaning blade 51Y, etc.) in contact with the surface. Substance supply devices 60Y, 160Y, and 260 are provided. The lubrication substance supply device is provided outside the drum cleaning device 50Y and the like. Moreover, the lubricating substance supply device makes the opening edge of the casing 61Y, 161Y, 261 opened only on the side facing the surface of the photosensitive drum 2Y contact the photosensitive drum 2Y, etc., and the inner wall surface of the casing And a lubricating substance accommodated in a closed space surrounded by the surface portion of the photosensitive drum 2Y and the like is supplied in the closed space. With such a configuration, as described above, it becomes possible to use all the lubricating substances for supplying to the photosensitive drum 2Y and the like, preventing the lubricating substances from being wasted and reducing the size of the apparatus. Can be achieved.

  Further, in the lubricant material supply device 160Y for the photosensitive drum in the second embodiment, the lubricant material 62Y in a state of fluidity in the internal space (closed space) of the casing 161Y causes the inner wall surface of the casing due to gravity. Are moved toward the surface portion of the photosensitive drum 2Y forming the internal space. Therefore, as described above, the lubricating substance 62Y does not remain in the casing 161Y, and the lubricating substance 62Y can be used up completely.

  In addition, the lubricating substance supply device 260 for the intermediate transfer belt in the second embodiment rubs both the solid lubricating substance 262 and the solid lubricating substance and the surface portion of c in the internal space of the casing 261. And a brush roller 266 that is a brush-like rotating body that rotates as described above. Further, the lubricating material supply device 260 supplies the powdery lubricating material scraped from the solid lubricating material 262 by the brush roller 266 to the surface portion of the internal space of the casing 261. The lubrication substance supply device 260 is configured such that the brush roller 266 rubs the casing inner wall surface portion in which the powdery lubrication substance stays in the internal space of the casing 261. With such a configuration, as described above, the powdery lubricating substance does not remain in the casing 261, and the lubricating substance can be used up without waste.

  In addition, in the above-described first and second embodiments, the lubricating substance supply devices 60Y and 160Y for the photosensitive drum have the lubricating substance supply position with respect to the surface of the photosensitive drum 2Y, and the drum cleaning with respect to the surface of the photosensitive drum 2Y. It is disposed downstream of the cleaning position of the apparatus 50Y in the photosensitive drum surface movement direction and upstream of the development area, which is a toner adhesion position with respect to the surface of the photosensitive drum 2Y, in the photosensitive drum surface movement direction. Yes. Similarly, the lubricating substance supply device 260 for the intermediate transfer belt in the second embodiment is also configured so that the lubricating substance supply position with respect to the surface of the intermediate transfer belt 12 is cleaned by the belt cleaning device 16 with respect to the surface of the intermediate transfer belt 12. The intermediate transfer belt is disposed downstream of the intermediate transfer belt in the direction of movement of the intermediate transfer belt and upstream of the primary transfer region, which is the position where the toner adheres to the surface of the intermediate transfer belt 12. Therefore, as described above, the toner hardly enters the lubricating substance supply devices 60Y, 160Y, and 260, and it is possible to prevent the occurrence of background contamination due to the mixed toner.

  In the printer according to the second embodiment, the photosensitive drum 2Y as a latent image carrier and the charging roller 31Y as a charging member are brought into contact with or close to the surface portion of the photosensitive drum cleaned by the drum cleaning device 50Y. A charger 30Y as a uniform charging means for uniformly charging the surface portion thereof, and an optical writing unit 10 as a latent image forming means for forming a latent image on the surface portion uniformly charged by the charger. A developing device 40Y as developing means for developing the latent image formed on the surface of the photosensitive drum 2Y by attaching toner, and a toner image formed on the surface of the photosensitive drum by the developing device. And a secondary transfer bias roller 18 as transfer means for transferring to the intermediate transfer belt 12. The lubricating substance supply device 160Y for the photosensitive drum is arranged such that the lubricating substance supply position is on the downstream side in the moving direction of the photosensitive drum surface from the uniform charging position of the charger 30Y with respect to the photosensitive drum surface. Has been placed. Therefore, as described above, the amount of the lubricating material 62Y adhering to the charging roller 31Y of the charger 30Y can be reduced, and the occurrence of charging failure can be suppressed. As a result, as described above, it is possible to employ a contact charging method that is more advantageous than the non-contact charging method for the image forming apparatus that supplies the lubricating substance 62Y.

  Further, in the above-described first and second embodiments, the lubrication substance supply devices 60Y, 160Y, and 260 move the surface of the photosensitive drum 2Y and the like relative to the surface of the photoreceptor drum 2Y and the like. The opening edges of the casings 61Y, 161Y, and 261 that contact the surface of the photosensitive drum 2Y and the like on the downstream side can contact the surface of the photosensitive drum 2Y and the like with a uniform pressure in a direction orthogonal to the surface movement direction. It is formed by seal members 64Y, 164Y, 264 which are elastic bodies. Thereby, a substantially uniform amount of the lubricating substance can be adhered to the entire surface of the surface of the photosensitive drum 2Y or the like. In addition, by appropriately adjusting the contact pressure, contact angle, etc. of the seal members 64Y, 164Y, 264, it is possible to prevent unnecessary lubrication substances from adhering to the surface of the photoreceptor drum 2Y and the like. Therefore, it is possible to reduce the amount of the lubricious substance previously loaded in the printer, and it is possible to promote downsizing of the apparatus.

Further, the printers of the first and second embodiments described above are provided with the recycled toner conveying device 70Y as a toner recycling means for reusing the transfer residual toner collected by the drum cleaning device 50Y for image formation. Therefore, it is possible to provide an environment-friendly system with less wasteful waste of toner. In addition, there is an effect that life regulation due to the full waste toner tank is relaxed. In particular, as described in the first embodiment, if the lubricating substance supply device 60Y is arranged so that the lubricating substance supply position is close to the downstream side in the moving direction of the photosensitive drum surface of the cleaning position of the drum cleaning device 50Y, the above-described case. As described above, it becomes difficult for the lubricating substance to be mixed into the drum cleaning device 50Y. Therefore, even in an image forming apparatus having a mechanism for supplying the lubricant 62Y that adversely affects the frictional charging of the toner to the photosensitive drum 2Y, the drum cleaning apparatus 50Y can sufficiently suppress the occurrence of background stains. A toner recycling means for reusing the collected transfer residual toner can be applied. Note that the configuration in which the toner recycling unit is used in the image forming apparatus having the mechanism for supplying the lubricant material that adversely affects the frictional charging of the toner to the photosensitive drum in this manner is such that the lubricant material supply device is provided outside the drum cleaning device. Even if the inner space of the casing is not a closed space shielded from the outside, the configuration is effective.
Further, as described above, if only the lubricating substance supply devices 60Y, 160Y, 260 are configured to be detachable from the printer main body alone, the replacement timing of the lubricating substance supply device can be changed in addition to the photosensitive drum 2Y or the like. Therefore, the degree of freedom of design can be increased.

  In the first and second embodiments described above, a process cartridge that is detachable from the printer main body and includes at least the photosensitive drum 2Y and the lubricating substance supply devices 60Y and 160Y is integrated. Adopted. Therefore, at least the photosensitive drum 2Y and the lubricating substance supply devices 60Y and 160Y that need to be replaced can be easily replaced, and user convenience can be improved. In particular, in the first and second embodiments, the lubricating material is supplied to the surface of the photosensitive drum. Therefore, as described above, the lifetime of the photosensitive drum 2Y having the shortest lifetime can be increased. it can. Therefore, the replacement frequency of the process cartridge can be reduced, and user convenience can be further improved. In addition, in the first and second embodiments, since the transfer residual toner is reused in the developing device 40Y, the replacement frequency of the toner container can be reduced. Therefore, in the process cartridge including the toner container, the replacement frequency of the process cartridge can be further reduced. In particular, in the first and second embodiments, individual process cartridges are prepared for each of the image forming units 1Y, 1M, 1C, and 1K, and there are a total of four process cartridges. The effect is beneficial.

In the first and second embodiments described above, a two-component developer is used, but the present invention can achieve the same effect even with a one-component developer. Further, the present invention is not a so-called tandem image forming apparatus, but a so-called one-drum type image in which a toner image of each color is sequentially formed on a single photosensitive drum and the color toner images are sequentially superimposed to obtain a color image. The present invention can be similarly applied to a forming apparatus, and can be applied not only to a color image forming apparatus but also to a monochromatic image forming apparatus. Needless to say, it can also be applied to devices.
Further, the lubricating substance supply devices 60Y, 160Y, and 260 exemplified in the first embodiment and the second embodiment described above are configured such that the surface moving member such as the transfer paper transport belt 118 in addition to the photosensitive drum 2Y and the intermediate transfer belt 12 is used. The same effect can be obtained even when applied to a lubricating substance supply device.

Next, the photoconductor used in the present invention will be described in detail.
The photosensitive member forms a photosensitive layer on a conductive support. Further, if necessary, a protective layer may be provided on the photosensitive layer. The photosensitive layer is composed of a charge generation layer and a charge transport layer, but a charge transport layer may be provided on the charge generation layer, or conversely, a charge generation layer may be provided on the charge transport layer. The charge generation layer and the charge transport layer may be mixed.
The diameter of the photoconductor used in the image forming apparatus of the present invention is 35 mm so as to secure a sufficient area so as to prevent the transfer residual toner from being mixed into the lubrication substance application area and to secure a high linear velocity. ˜100 mm, preferably 40˜80 mm. If the diameter of the photoconductor is less than 35 mm, the transfer residual toner is likely to be mixed in the lubrication substance application region, and the surface free energy of the photoconductor is likely to vary, which is not preferable. When the diameter of the photoreceptor exceeds 100 mm, the image forming apparatus becomes large, which is not preferable. As described above, a so-called process cartridge in which the image forming part is handled as one piece and maintenance and replacement are facilitated is preferably used. However, when the diameter of the photoconductor exceeds 100 mm, the volume and mass of the process cartridge both increase and become integral. It is not preferable to handle as because the workability is deteriorated.

The conductive support has a volume resistance of 10 ¹⁰ Ωcm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, or a metal oxide such as tin oxide or indium oxide. , By vapor deposition or sputtering, film or cylindrical plastic, paper coated, aluminum, aluminum alloy, nickel, stainless steel, etc. It consists of a pipe etc.

The charge generation layer is a layer mainly composed of a charge generation material. As the charge generation material, an inorganic or organic material is used, and typical examples include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squaric. Examples include acid dyes, phthalocyanine pigments, naphthalocyanine pigments, azulenium salt dyes, selenium, selenium-tellurium alloys, selenium-arsenic alloys, and amorphous silicon. These charge generation materials may be used alone or in combination of two or more.
The charge generation layer is obtained by dispersing the charge generation material together with a binder resin, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, 2-butanone, dichloroethane, or the like by a ball mill, attritor, sand mill, etc., and applying a dispersion. Can be formed. Application is performed by dip coating, spray coating, bead coating, or the like.
The binder resin used as appropriate is polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, silicone resin, acrylic resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl ketone resin, polystyrene, resin, polyacrylic. Examples thereof include resins and polyamide resins. The amount of the binder resin is suitably 0 to 2 parts with respect to 1 part of the charge generating material on a mass basis.
The charge generation layer can also be formed by a known vacuum thin film manufacturing method. The film thickness of the charge generation layer is usually 0.01 to 5 μm, preferably 0.1 to 2 μm.

The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in an appropriate solvent, and applying and drying the solution. Moreover, a plasticizer, a leveling agent, etc. can also be added as needed.
Among charge transport materials, low molecular charge transport materials include electron transport materials and hole transport materials.
Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4-one, 1,3,7-tri Examples thereof include electron accepting substances such as nitrodibenzothiophene-5,5-dioxide. These electron transport materials may be used alone or as a mixture of two or more.

Examples of hole transport materials include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane. , Styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These hole transport materials may be used alone or as a mixture of two or more.
When a polymer charge transport material is used as the charge transport material, it may be dissolved or dispersed in an appropriate solvent, and coated and dried to form a charge transport layer. The polymer charge transport material may be a material having a charge transporting substituent in the main chain or side chain in the low molecular charge transport material. Furthermore, if necessary, an appropriate amount of a binder resin, a low molecular charge transport material, a plasticizer, a leveling agent, a lubricating substance, or the like can be added to the polymer charge transport material.

As the binder resin used for the charge transport layer together with the charge transport material, polystyrene resin, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester resin, polyvinyl chloride resin, Vinyl chloride-vinyl acetate copolymer, polyvinyl acetate resin, polyvinylidene chloride resin, polyarylate resin, phenoxy resin, polycarbonate resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral resin, polyvinyl formal resin, polyvinyl toluene resin, acrylic resin And thermoplastic or thermosetting resins such as silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like.
Examples of the solvent include tetrahydrofuran, dioxane, toluene, 2-butanone, monochlorobenzene, dichloroethane, methylene chloride and the like.
The thickness of the charge transport layer may be appropriately selected in the range of 5 to 30 μm according to desired photoreceptor characteristics.

Examples of the plasticizer that is optionally added to the charge transport layer include dibutyl phthalate, dioctyl phthalate, and other general-purpose plasticizers. The amount used is 0 to 30% based on the weight of the binder resin. The degree is appropriate.
Examples of leveling agents that are optionally added to the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. About 0 to 1% is appropriate for the binder resin on the basis.

The content of the charge transport material contained in the photosensitive layer is preferably 40% by mass or more of the charge transport layer. If it is less than 40% by mass, a sufficient light decay time in the high-speed electrophotographic process cannot be obtained in pulsed light exposure in laser writing on the photoreceptor, which is not preferable.
The charge transport layer mobility in the photoreceptor is 3 × 10 ⁻⁵ cm ² / V · s under the condition of the charge transport layer electric field strength in the range of 2.5 × 10 ^{5 to} 5.5 × 10 ⁵ V / cm. It is preferable that it is above, and it is more preferable that it is 7 × 10 ⁻⁵ cm ² / V · s or more. This mobility can be adjusted as appropriate to achieve this under each use condition. This mobility may be obtained by a conventionally known TOF method.

In the photoreceptor, an undercoat layer can be formed between the conductive support and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is applied using a solvent, the resin is a resin having high resistance to general organic solvents. Is desirable.
Examples of such resins include polyvinyl alcohol resins, casein, water-soluble resins such as sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane resins, melamine resins, alkyd-melamine resins, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin.
Further, fine powder of metal oxide such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the undercoat layer in order to prevent moire and reduce residual potential.
This undercoat layer can be formed by using an appropriate solvent and coating method as in the case of the photosensitive layer. Furthermore, it is also useful to use a metal oxide layer formed by, for example, a sol-gel method using a silane coupling agent, a titanium coupling agent, a chromium coupling agent or the like as the undercoat layer.
In addition, the undercoat layer which the _Al 2 _{O 3} was formed by those anodized, organic matter such as polyparaxylylene _{(parylene), SiO, SnO 2, TiO} 2, ITO, Ce0 2 , etc. inorganic It is also effective to form the film by a vacuum thin film manufacturing method. The thickness of the undercoat layer is suitably from 0 to 5 μm.

In the photoreceptor, as a surface layer, a protective layer containing a filler is formed on the photosensitive layer for the purpose of protecting the photosensitive layer and improving durability.
Materials used for this protective layer include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether resin, allyl resin, phenol resin, polyacetal resin, polyamide resin, polyamideimide resin, polyacrylate resin , Polyallylsulfone resin, polybutylene resin, polybutylene terephthalate resin, polycarbonate resin, polyethersulfone resin, polyether resin, polyethylene terephthalate resin, polyimide resin, acrylic resin, polymethylpentene resin, polypropylene resin, polyphenylene oxide resin, polysulfone resin, Examples of the resin include AS resin, AB resin, BS resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, and epoxy resin. A filler is added to the protective layer for the purpose of improving wear resistance.
Examples of the filler include fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials such as titanium oxide, tin oxide, and potassium titanate in these resins.
The amount of filler added to the protective layer is usually 10 to 40%, preferably 20 to 30% on a mass basis. If the amount of the filler is less than 10%, the wear is large and the durability is inferior, and if it exceeds 40%, the increase in the bright part potential at the time of exposure becomes remarkable, and the decrease in sensitivity cannot be ignored.
Furthermore, a dispersion aid can be added to the protective layer in order to improve the dispersibility of the filler. As the added dispersion aid, those used in paints and the like can be used as appropriate, and the amount is usually 0.5 to 4%, preferably 1 to 2% based on the amount of filler contained on a mass basis. .
Moreover, it is also effective to add the above-described charge transport material to the protective layer, and an antioxidant can be added as necessary. The antioxidant will be described later.
As a method for forming the protective layer, a normal coating method such as a spray method is employed. The thickness of the protective layer is suitably about 0.5 to 10 μm, preferably about 4 to 6 μm.
It is important for the wear resistance and image characteristics that the form of the filler in the protective layer be constant. In other words, the presence of the protective layer does not impair the sensitivity and electrostatic stability of the photosensitive layer, and does not impair the fineness of exposure, and it can contribute to higher resolution and faster response by thinning based on wear resistance. Is.
In order to satisfy this requirement, the filler content in an arbitrary cross section of the protective layer needs to be 3 to 5% as an area occupation ratio in the plane. Moreover, in the particle size distribution in which the filler contained in the protective layer contains secondary particles, the area occupied by the filler having a peak of 0.2 to 0.3 μm and a particle size of 0.3 μm or more in an arbitrary cross section of the protective layer Needs to be 10 to 30% of the total area occupied by the filler in the plane. As a result of investigations by the inventors, when the above range is not satisfied, it was confirmed that the residual potential increased, the sensitivity decreased, the resolution decreased, the wear resistance decreased, and abnormal image generation due to filming occurred.
Control of the presence form of the filler in the protective layer is possible by the particle size and distribution of the filler material used, the coating liquid formulation, and the coating apparatus, and the use of a dispersion aid is effective.

It is also possible to form another intermediate layer between the photosensitive layer and the protective layer. In the intermediate layer, a binder resin is generally used as a main component. Examples of the binder resin include polyamide resin, alcohol-soluble nylon, water-soluble polyvinyl butyral resin, polyvinyl butyral resin, and polyvinyl alcohol resin. As a method for forming the intermediate layer, the above-described normal coating method is employed. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.
In order to improve environmental resistance, antioxidants, plasticizers, lubricants, UV absorbers, low-molecular charge transporting substances and leveling agents are added to each layer, especially for the purpose of preventing a decrease in sensitivity and an increase in residual potential. can do.

  Examples of the antioxidant that can be added to each layer include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl- 3- (4-hydroxy-3,5-di-tert-butylphenol), 2,2-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2-methylene-bis- (4-ethyl) -6-tert-butylphenol), 4,4-thiobis- (3-methyl-6-tert-butylphenol), 4,4-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3- Tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl Benzene, tetrakis- [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric Acid] phenol compounds such as glycol ester, tocopherols, N-phenyl-N-isopropyl-p-phenylenediamine, N, N-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec Paraphenylenediamines such as -butyl-p-phenylenediamine, N, N-di-isopropyl-p-phenylenediamine, N, N-dimethyl-N, N-di-t-butyl-p-phenylenediamine, 5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, -Hydroquinones such as dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone, dilauryl-3,3-thiodipropionate, distearyl- Organic sulfur compounds such as 3,3-thiodipropionate, ditetradecyl-3,3-thiodipropionate, triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, And organic phosphorus compounds such as tri (2,4-dibutylphenoxy) phosphine.

  Examples of plasticizers that can be added to each layer include triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate , Phosphate ester plasticizers such as triphenyl phosphate, dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-phthalate n-octyl, dinonyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl phthalate Phthalate ester plasticizers such as decyl, dibutyl fumarate, dioctyl fumarate, aromatic carboxylic acid ester plasticizers such as trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate, and dibutyl adipate , Di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, n-octyl adipate, diisodecyl adipate, dicapryl adipate, di-2-azelate Ethylhexyl, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2-ethoxyethyl sebacate, dioctyl succinate, diisodecyl succinate, tetrahydrophthalic acid Dioctyl, Tetrahi Aliphatic dibasic acid ester plasticizers such as di-n-octyl lophthalate, fatty acids such as butyl oleate, glycerin monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin Ester derivative plasticizer, methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate, epoxidized soybean oil, epoxidized linseed oil, epoxy butyl stearate Epoxy plasticizers such as decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate, Dihydric alcohol ester plasticizers such as diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate, chlorine-containing plasticizers such as chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, and methoxychlorinated fatty acid methyl, polypropylene Polyester plasticizers such as adipate, polypropylene sebacate, polyester, acetylated polyester, p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide , Sulfonic acid derivative plasticizers such as p-toluenesulfone-N-cyclohexylamide, triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, Citric acid derivative plasticizers such as tri-2-ethylhexyl citrate, acetylcitrate-n-octyldecyl, etc., terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietic acid Etc.

  Examples of lubricants that can be added to each layer include hydrocarbon compounds such as liquid paraffin, paraffin wax, microwax, and low-polymerized polyethylene, and fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Compounds such as fatty acid amide compounds such as stearylamide, palmitylamide, oleinamide, methylenebisstearoamide, ethylenebisstearoamide, lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, fatty acid polyglycol esters, etc. Ester compounds, alcohol compounds such as cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol, lead stearate, cadmium stearate, barium stearate, Calcium stearic acid, zinc stearate, metal soaps such as magnesium stearate, carnauba wax, candelilla wax, beeswax, spermaceti, insect wax, natural waxes such as montan wax, other silicone compounds, fluorine compounds, and the like.

  Examples of ultraviolet absorbers that can be added to each layer include 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2,4-trihydroxybenzophenone, 2,2,4,4-tetrahydroxybenzophenone, and 2,2-dihydroxy. Benzophenone UV absorbers such as 4-methoxybenzophenone, salsylate UV absorbers such as phenyl salsylate, 2,4 di-t-butylphenyl 3,5-di-t-butyl 4-hydroxybenzoate, (2-hydroxy Phenyl) benzotriazole, (2-hydroxy5-methylphenyl) benzotriazole, (2-hydroxy5-methylphenyl) benzotriazole, (2-hydroxy3-tertiarybutyl 5-methylphenyl) 5-chlorobenzotriazole, etc. Benzotria UV absorbers, cyanoacrylate UV absorbers such as ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate, nickel (2,2 thiobis (4-t- Octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and other quencher (metal complex) UV absorbers, bis (2,2,6,6-tetramethyl-4- Piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy ] Ethyl] -4- [3- (3,5-di-t-butyl) 4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4 5] HALS (hindered amine) ultraviolet absorbers such as undecane-2,4-dione and 4-benzoyloxy-2,2,6,6-tetramethylpiperidine.

In this manner, a photosensitive member in which a photosensitive layer and a protective layer are formed on a conductive substrate, and an undercoat layer and an intermediate layer are formed as desired. It improves and improves durability. Furthermore, the photoreceptor has excellent durability and stability even in high-speed electrophotographic processes by making the form of the filler in the protective layer constant as described above, and has excellent wear resistance. Photoconductor. Furthermore, by supplying zinc stearate onto the protective layer, filming can be suppressed in a state where the wear resistance is good. Further, in the electrophotographic process including the photoreceptor, during non-image formation By repeating the toner adhesion on the photosensitive member and the toner collecting operation in the cleaning unit, it is effective in suppressing image flow while maintaining wear resistance.
In the illustrated example, the photoconductor is in the form of a drum, but it may also be in the form of a belt having a high surface hardness.

  In one embodiment of the present invention, for example, 0.05 to 0.2% by mass of a lubricating substance (for example, zinc stearate) is externally added to the toner. In this way, the lubricating substance can be applied to the surface of the photoreceptor.

  The toner includes a binder resin, a colorant, and a charge control agent as main components, and other additives are added as necessary. Specific examples of the binder resin include polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, and styrene-vinyl chloride copolymer. Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Polymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, Styrene-phenyl methacrylate copolymer, etc.), styrene-α -Styrenic resins such as methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer (monopolymer or copolymer containing styrene or styrene substitution product), vinyl chloride resin, rosin-modified maleic acid resin Phenyl resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral, and the like can be used.

  As coloring materials (for example, yellow, magenta, cyan, and black) used for the toner, those known for toner can be used. The amount of the coloring material is suitably 0.1 to 15 parts by mass, more preferably 0.15 to 9 parts by mass with respect to 100 parts by mass of the binder resin.

  Specific examples of the charge control agent include a nigrosine dye, a chromium-containing complex, a quaternary ammonium salt, and the like, which are properly used depending on the polarity of the toner particles. The amount of the charge control agent is 0.1 to 10 parts by mass, more preferably 0.2 to 7 parts by mass with respect to 100 parts by mass of the binder resin.

In addition, it is advantageous to add a fluidity imparting agent to the obtained toner particles. As the fluidity-imparting agent, fine particles of metal oxides such as silica, alumina, magnesia, zirconia, ferrite, magnetite and the like, and silane coupling agent, titanate coupling agent, zircoaluminate, quaternary ammonium salt, fatty acid, Surface treatment or coating with fatty acid metal salt, fluorine-based activator, solvent, polymer or other treatment agent, fine particles of fatty acid such as stearic acid or zinc stearate or metal salt thereof, and these fine particles with surface treatment In addition, polymer fine particles such as polystyrene, polymethyl methacrylate, and polyvinylidene fluoride, and those fine particles that are surface-treated or coated with the above-described treatment agent are used. These fluidity imparting agents have a particle size in the range of 0.01 to 3 μm.
The addition amount of these fluidity imparting agents is preferably in the range of 0.1 to 7.0 parts by weight, particularly 0.2 to 5.0 parts by weight with respect to 100 parts by weight of the toner particles. The mixing method of the toner particles and the fluidity-imparting agent is carried out so that the powder is moved at a high speed by an air flow or mechanical force in a fluid state, and does not substantially cause pulverization. Examples of the mixer include a high-speed flow type mixer such as a Henschel mixer and a UM mixer.

As a method for producing a toner for two-component developer, it can be produced by various known methods or a combination thereof. For example, in the kneading and pulverization method, a binder resin, a colorant such as carbon black, and necessary additives are dry-mixed, heated and melt-kneaded with an extruder or two-roll, three-roll, etc., and after cooling and solidification Then, the toner is pulverized by a pulverizer such as a jet mill and classified by an airflow classifier. In addition, a toner can be directly produced from a monomer, a colorant, and an additive by suspension polymerization or non-aqueous dispersion polymerization.
The carrier core material is generally made of itself or having a coating layer on the core material. The core material of the resin-coated carrier that can be used in the present invention is ferrite or magnetite. The particle size of the core material is 20 to 65 μm, preferably about 30 to 60 μm.
Fluorine-containing monomers used for carrier coating layer formation include vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinyl ether substituted with fluorine atoms, and vinyl ketone substituted with fluorine atoms. Examples of the polymer include vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, perfluoroalkyl vinyl ether-vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride. Polymers, tetrafluoroethylene copolymers, polymers containing vinyl ethers substituted with fluorine atoms, polymers containing vinyl ketones substituted with fluorine atoms, fluorinated alkyl copolymers Relate polymer, or a fluorinated alkyl methacrylate polymer.
Components copolymerized with the fluorine-containing monomer include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, and benzyl acrylate. Benzyl methacrylate, acrylic acid amide, methacrylic acid amide, cyclohexyl acrylate, cyclohexyl methacrylate, hydroxyethyl acrylate, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, ethylene, propylene, and the like. As a method for forming the coating layer, a resin may be applied to the surface of the carrier core particle by means of a spraying method, a dipping method, or the like, as in the past.

EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example.
Example 1
An undercoat layer, a charge generation layer, a charge transport layer, and a protective layer are applied in that order on an aluminum substrate (conductive support) having a diameter of 60 mm, and then dried to form a 3.5 μm undercoat layer, 0.15 μm A photoconductor comprising a charge generation layer, a 22 μm charge transport layer, and a protective layer of about 4.5 μm was prepared. At this time, the coating of the protective layer was performed by a spray method, and the others were performed by a dip coating method. 22.5% by mass of alumina having an average particle diameter of 0.25 μm was added to the protective layer.
The surface free energy of this photoconductor is measured according to the preferred method for measuring surface free energy of the present invention, and the contact angle of diiodomethane, α-bromonaphthalene, glycerin, diethylene glycol is set in a direction perpendicular to the rotation direction of the photoconductor. Measurements were made at 14 points at intervals of 20 mm from a point 45 mm from the end of the plate.
When measuring the contact angle with diiodomethane, α-bromonaphthalene, glycerin, or diethylene glycol, measure by rotating the photoconductor so that the distance from the edge is constant and the location measured with each solvent is not measured with another solvent. did. The surface free energy of the photoreceptor measured from the contact angle of each solvent was 50.2 to 50.7 mN / m, and the difference between the maximum value and the minimum value of the surface free energy at 14 locations was 0.0 to 0.2 mN / m.
This photoconductor was incorporated into imagio Neo C600 (Ricoh, tandem color image forming apparatus having a mechanism for applying zinc stearate to the photoconductor upstream of the cleaning blade), and 0.16% by mass of zinc stearate was externally added. Image formation was performed using a toner having an average particle diameter of 6.4 μm. A total of 70,000 image formation tests were conducted with 5 sheets of 2 types of charts with an average image area ratio of 6% averaged and 5 sheets of images as one job.
When the surface free energy of each of the photoconductors for black, yellow, cyan, and magenta was measured as described above after completion of the image formation test, the average surface free energy of each photoconductor was 27.0, 26.4, 27.5, and 27.9 mN, respectively. The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 1.2, 1.6, 2.3, and 1.4 mN / m, respectively. When a halftone image of each color, a solid image, a grid image, and a landscape photograph taken with a digital still camera were formed, high quality images were obtained for all the images.

(Example 2)
In Example 1, the zinc stearate coating mechanism of the image forming apparatus was modified from the upstream side to the downstream side of the cleaning blade, and instead of a chart with an average image area ratio of 6% in which characters were averaged, The left half is a chart in which image data is arranged and the right half is lined up. The left half has an average image area ratio of 20%, the right half has an average image area ratio of 2%, and the average image area ratio of the entire chart is about An image formation test was conducted in the same manner as in Example 1 except that 30,000 sheets of images were formed using a 10% chart.
As in Example 1, the surface free energy of each of the photoreceptors for black, yellow, cyan, and magenta after the image formation test was measured. The average surface free energy of each photoreceptor was 26.8, 27.8, 27.2, respectively. The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 3.9, 2.7, 4.2, and 2.1 mN / m, respectively. When a halftone image of each color, a solid image, a grid image, and a landscape photograph taken with a digital still camera were imaged, a high quality image was obtained.

(Comparative Example 1)
In Example 2, an image formation test was conducted in the same manner as in Example 2 except that the zinc stearate coating mechanism was not modified.
When the surface free energy of each of the photoreceptors for black, yellow, cyan and magenta after the image formation test was measured in the same manner as in Example 2, the average surface free energy of each photoreceptor was 31.2, 28.8, 29.4, The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 7.5, 4.1, 8.7, and 5.9 mN / m, respectively. When a halftone image of each color was output, band-shaped density unevenness occurred in the black, cyan, and magenta images.

(Example 3)
In Example 2, an image formation test was conducted in the same manner as in Example 2 except that a toner having an average particle size of 5.8 μm externally added with 0.15% by mass of zinc stearate was used.
When the surface free energy of each of the photoreceptors for black, yellow, cyan and magenta after the image formation test was measured in the same manner as in Example 2, the average surface free energy of each photoreceptor was 27.0, 27.5, 27.4, The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 4.1, 3.3, 2.9, and 1.8 mN / m, respectively. When a halftone image of each color, a solid image, a grid image, and a landscape photograph taken with a digital still camera were imaged, a high quality image was obtained.

Example 4
In Example 3, a chart in which image data is arranged in the left half and characters are arranged in the right half, the left half has an average image area ratio of 22%, the right half has an average image area ratio of 2%, and the average of the entire chart The image area ratio is about 10%, the image is formed in the same manner as in Example 3, except that 50,000 images are formed and a toner having an average particle diameter of 5.8 μm externally added with 0.08% by mass of zinc stearate is used. Went.
As in Example 3, the surface free energy of each photoconductor for black, yellow, cyan, and magenta was measured. The average surface free energy of each photoconductor was 27.7, 28.8, 28.3, and 27.4 mN / m, respectively. The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 2.9, 3.5, 3.3, and 4.0 mN / m, respectively. When a halftone image of each color, a solid image, a grid image, and a landscape photograph taken with a digital still camera were imaged, a high quality image was obtained.

(Comparative Example 2)
In Example 4, an image forming test was performed in the same manner as in Example 4 except that an image forming apparatus in which the coating mechanism of zinc stearate was not modified was used and 10,000 images were formed.
After the image formation test as in Example 4, the surface free energy of each photoconductor for black, yellow, cyan, and magenta was measured, and the average surface free energy of each photoconductor was 34.5, 28.0, 29.3, respectively. The difference between the maximum value and the minimum value of the surface free energy of each photoconductor was 12.1, 9.3, 15.2, and 6.1 mN / m, respectively. When a halftone image of each color was output, band-shaped density unevenness occurred in the black, yellow, cyan, and magenta images.

  According to the present invention, an image forming apparatus and a process cartridge capable of forming a high quality image and having excellent durability are provided.

FIG. 3 is an enlarged view illustrating a schematic configuration of an image forming unit for yellow among image forming units provided in the printer according to the first embodiment. It is a schematic block diagram of the printer of FIG. It is an enlarged view showing a schematic configuration of a yellow image forming unit in a modified example. FIG. 4 is a schematic configuration diagram illustrating a main part of a printer according to a second embodiment. It is a schematic block diagram which shows the lubricous substance supply apparatus which supplies a lubricous substance to the photosensitive drum of a printer. It is a schematic block diagram which shows the lubricous substance supply apparatus by which the structure which a lubricous substance remains in a casing was employ | adopted. FIG. 2 is a schematic configuration diagram illustrating a lubricating substance supply device that supplies a lubricating substance to an intermediate transfer belt of the printer. When a substance is a solid and a liquid, it is a figure which shows the state from which the droplet reached the equilibrium, maintaining the contact angle (theta) on the solid surface.

Explanation of symbols

1Y, 1M, 1C, 1K Image forming unit 2Y, 2M, 2C, 2K Photosensitive drum 16 Belt cleaning device 30Y Charger 31Y Charge roller 40Y, 40M, 40C, 40K Developer 50Y, 50M, 50C, 50K Drum cleaning device 51Y Cleaning blade 60Y, 60M, 60C, 60K, 160Y, 160M, 160C, 160K, 260, 360Y Lubricating substance supply device 62Y Lubricating substance 262, 362Y Solid lubricating substance 266, 363Y Brush roller

Claims (11)

  An image forming apparatus that includes a photoconductor having a surface free energy of 45 mN / m or more and that uses toner as a developer to form an image. When forming an image, the surface free energy of the image forming region of the photoconductor Image forming characterized in that a lubricating substance can be supplied to the photoconductor so that the average is 32 mN / m or less and the difference between the maximum and minimum surface free energy is 5 mN / m or less. apparatus.   2. The image forming apparatus according to claim 1, wherein the surface free energy of the photoconductor during image formation is measured for each of the plurality of divided areas in a direction orthogonal to the rotation direction of the photoconductor. An image forming apparatus having a width of 50 mm or less.   3. The image forming apparatus according to claim 1, wherein a lubricant is supplied to the photoconductor after cleaning the residual toner on the photoconductor.   4. The image forming apparatus according to claim 3, wherein the photosensitive member has a diameter of 35 to 100 mm.   5. The image forming apparatus according to claim 1, wherein the lubricating substance is a metal soap. 6. The image forming apparatus according to claim 1, wherein the surface free energy of the photoconductor is measured by a contact angle between the surface of the photoconductor and a liquid in which each component of the surface free energy is known. The surface free energy of a solid is measured using the following formula 7 based on the extended Fowkes theory, and the surface free energy is obtained by linear regression from contact angle data with four or more liquids. Image forming apparatus.

(However, in the formula, gamma _L is, .Ganma represents the surface free energy of the liquid represented by ^{_{γ a L + γ b L +}} γ C L a L is, .Ganma ^b representing the dispersive component of the surface free energy of the liquid _L represents a dipole component of the surface free energy of the liquid, γ ^C _L represents a hydrogen bond component of the surface free energy of the liquid, γ ^a _S represents ^a dispersed component of the surface free energy of the solid, γ ^b _(S represents the dipole component of the surface free energy of the solid, γ ^C _S represents the hydrogen bond component of the surface free energy of the solid, and θ represents the contact angle.)   7. The image forming apparatus according to claim 6, wherein the liquid for measuring the contact angle for obtaining the surface free energy of the photoreceptor is selected from diiodomethane, α-bromonaphthalene, diethylene glycol, glycerin and formamide. Forming equipment.   8. The image forming apparatus according to claim 1, wherein the toner used has an average particle diameter of 7 [mu] m or less.   9. The image forming apparatus according to claim 1, wherein a maximum resolution at which an image can be formed by the image forming apparatus is 1000 dpi or more.   The image forming apparatus according to claim 1, wherein the image forming apparatus is capable of forming a color image. 11. A process cartridge that can be attached to and detached from the image forming apparatus main body according to claim 1, wherein the process cartridge includes a photoconductor having a surface free energy of 45 mN / m or more, and forms an image. At this time, the lubricant is added to the photosensitive material so that the average surface free energy of the image forming area of the photoconductor is 32 mN / m or less and the difference between the maximum value and the minimum value of the surface free energy is 5 mN / m or less. A process cartridge configured to be supplied to a body.

Images