JP2007333918A - Cleaning device, image forming apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device in which sufficient cleaning performance of an image carrier surface can be stably exhibited. <P>SOLUTION: A cleaning member 23 is made to abut on the surface of the image carrier of a tangent L1 in such a manner that its surface is made into an acute angle with a cleaned side, i.e., is made to abut thereon at an angle belonging to a counter type (leading type), and its pivot 21 exists on an upper side than the tangent L1 to a photoreceptor drum 1 and a right side of a normal L2, namely, in a range of a region A. The component of force acting on the cleaning member 23 in the tangent L1 direction during the standstill of the photosensitive drum 1 and the component of force acting on the cleaning member 23 in the tangent L1 direction during driving of the photoreceptor drum 1 turn to be a vector in the same direction and there is no more abrupt change of direction in the working force at the front end of the cleaning member 23 and a fault, such as a deficit of the front end due to long-term use can be eliminated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning device that presses and contacts the front end of a cleaning member against the surface of an image carrier to remove toner remaining on the surface of the image carrier, an image forming apparatus using the same, and a process cartridge.

  Conventionally, in electrophotographic image formation, a latent image by an electrostatic charge is formed on an image carrier such as a photoconductive substance, and charged toner particles are attached to the electrostatic latent image to form a visible image. Forming. The visible image formed by the toner is finally transferred to a transfer medium such as paper, and then fixed to the transfer medium by heat, pressure, solvent gas, or the like, and becomes an output image.

  These image forming methods include a so-called two-component development method that uses friction charging by stirring and mixing toner particles and carrier particles by a method of charging toner particles for visualization, and without using carrier particles. In other words, the toner particles are roughly classified into so-called one-component development systems in which charge is imparted to toner particles. In addition, the one-component development method is classified into a magnetic one-component development method and a non-magnetic one-component development method depending on whether or not a magnetic force is used for holding toner particles on the developing roller.

  Up to now, in copiers that require high speed and image reproducibility, and multi-function machines based on these, two components are required due to demands such as toner particle charging stability, start-up stability, and long-term image quality stability. Many developing methods have been adopted, and one-component developing methods have been often used for small printers, facsimiles, and the like that require large space saving and low cost. In particular, in recent years, colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever.

  In these electrophotographic image forming apparatuses, a drum-shaped or belt-shaped image carrier (generally a photosensitive member) is uniformly charged while rotating, regardless of the development method, and laser light, etc. Thus, a latent image pattern is formed on the image carrier, and this is visualized with toner in the developing device, and the toner image is transferred onto the transfer medium.

  The toner component that has not been transferred remains on the image carrier after the toner image is transferred to the transfer medium. When these residues are conveyed to the charging process as they are, they often inhibit uniform charging of the image carrier. Therefore, generally, after passing through the transfer process, the toner component remaining on the image carrier is removed in the cleaning process, and the surface of the image carrier is sufficiently cleaned and then charged. . In particular, a contact charging method in which a charging member is brought into contact with the surface of the image carrier and charging is performed by charge injection or discharge in a region near the contact portion, or a charging member is disposed in the vicinity of the surface of the image carrier. In the charging by the proximity charging method in which charging is performed by discharging in a large gap, foreign matters such as residual toner components may be transferred to the charging member and change the surface state of the charging member. Cleaning is important.

  For this reason, many studies have been made on cleaning devices regardless of the type of charging device. In particular, the blade cleaning method has been widely studied because of its simplicity and low cost.

  For example, in Patent Document 1 and Patent Document 2, a cleaning blade member having a rebound resilience of 35 to 75% is brought into contact with the rotation direction of the image carrier in the counter direction, and the static friction coefficient of the image carrier with respect to the cleaning member is disclosed. An image forming method for processing the surface of the image carrier so as to be 1.0 or less is disclosed, and thereby, the cleaning blade member is turned over, the cleaning is poor, the image carrier surface is worn, damaged, and the electrophotographic performance is deteriorated. It can be eliminated.

  However, since the image carrier undergoes a charging process in the process of repeated image formation, the surface of the image carrier always receives and transfers charges, and therefore the surface state of the image carrier is not usually constant. That is, even if the initial static friction coefficient is 1.0 or less, the range is not always maintained, and particularly when organic fine particles are previously contained in the uppermost layer on the surface of the image carrier. However, since it is inevitable that the state change due to the charging process described above and the surface state change due to the fixing of the toner remaining component or the like cannot be avoided, it has not always been possible to maintain sufficiently stable cleaning performance over time.

  Further, Patent Document 3 discloses a cleaning that exhibits good cleaning performance by satisfying a certain relationship among the cleaning blade Young's modulus, the cleaning blade thickness, and the protruding amount of the blade with characteristic values that determine the cleaning angle during the cleaning operation. An apparatus is disclosed. According to Patent Document 3, the cleaning angle is determined in consideration of the amount of deflection of the blade from the shape and characteristics of the cleaning blade, and based on this, the relationship for realizing good cleaning characteristics is defined, and the toner A certain effect on the cleaning properties is shown.

  However, in the reading mechanism disclosed in Patent Document 3, the tangential direction component of the surface of the photosensitive member at the ridge line contact point and the tangential direction component during driving of the force that the cleaning blade pushes the photosensitive member when stationary are opposite to each other. This is a direction vector. That is, when the photosensitive member is repeatedly driven and stopped for a long period of time, a large distortion is repeatedly applied to the ridge line portion of the cleaning blade, so that the blade may be chipped.

  In Patent Document 4 (see, for example, FIG. 4), the support shaft of the cleaning blade is on the same side as the photoconductor with respect to the tangent line of the photoconductor at the contact point where the tip of the cleaning blade is pressed against the surface of the photoconductor. A cleaning device is illustrated. According to the cleaning device of this figure, the frictional force in the tangential direction applied to the above-described cleaning blade tip (the ridge line portion of the cleaning blade) is a vector in the same direction. Can be expected. However, in the configuration shown in FIG. 4 of the same document, the position of the support shaft is extremely limited, and it is extremely difficult to control the direction of the force that presses the cleaning blade against the photosensitive member. For this reason, in the invention disclosed in Patent Document 4, the pressure contact force cannot be sufficiently increased, and the cleaning performance is inferior.

  Conversely, in order to control the direction of the force that presses the cleaning blade against the photosensitive member more widely, the support shaft needs to be positioned so as not to interfere with the image carrier, which tends to complicate the mechanism. This not only hinders the downsizing of the forming apparatus, but also has a disadvantage in terms of parts cost and manufacturing cost.

  On the other hand, in recent years, toners formed using a polymerization method have been used to improve image quality and reduce manufacturing energy. These polymerized toners have excellent characteristics such as fewer angular portions and smaller average particle diameters than toners produced by a pulverization method. However, these features are affected by the shape and particle size of a method for cleaning the surface of the image carrier by pressing the edge of a cleaning member represented by rubber blade cleaning against the surface of the image carrier. As a result, it is difficult for the edge portion to be dammed, and the residual toner component tends to be poorly cleaned.

  Several proposals have been made so far for a cleaning device corresponding to such a toner cleaning failure. For example, Patent Document 5 discloses an image forming apparatus that uses an average volume diameter D and an average circularity S of a toner to set a pressing force that satisfies a predetermined condition. According to the disclosure of Patent Document 5, when the pressure contact force f is increased in counter-type blade cleaning, problems such as squeal of the cleaning blade and creaking occur. Therefore, an upper limit value is set as an empirical value. It is said that it is necessary. However, the upper limit value is for the general blade cleaning shown in FIG. 6 in the patent document, and for the cleaning device having the configuration as shown in FIG. No consideration is given.

  Further, for example, in order to clean a toner having a smaller toner average particle diameter and a more spherical shape, Patent Document 6 discloses a friction coefficient between the toner and the image carrier, a friction coefficient between the toner and the blade, and a toner and an image. A cleaning device is disclosed that defines the relationship between the adhesion force of the carrier, the force that the toner receives from the blade, and the angle formed between the blade and the image carrier (cleaning angle). In Patent Document 6, a cleaning device having excellent cleaning properties is proposed in consideration of rotation (autorotation) of toner to be cleaned, but the direction of the pressure contact force of the cleaning blade is not considered.

  As described above, it is not yet sufficient, and it remains an important problem that the surface of the image bearing member is reliably and stably cleaned with a simple configuration, and it is not sufficient to suppress defects such as chipping of the cleaning member for a long period of time. It was.

JP 09-292722 A Japanese Patent Laid-Open No. 08-83028 JP-A-5-119686 JP 61-122682 A JP 2000-330441 A JP 2005-99125 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the present invention, and has as its object to provide a cleaning device that can stably exhibit a sufficient cleaning performance of the surface of an image carrier, and uses this cleaning device. Another object of the present invention is to provide an image forming apparatus and a process cartridge capable of stably obtaining a good quality image.

  As a result of continuous studies to solve the above-mentioned problems of the prior art, the inventors of the present invention have formed an acute angle between the cleaning member fixed to the swingable cleaning member support and the cleaned surface of the image carrier. In the cleaning device that is pressed against the surface of the image carrier, the positional relationship between the tip of the cleaning member and the support shaft of the cleaning member support is important, and thereby the cleaning member exhibits excellent cleaning performance. It has been found that the improvement effect of being effective in suppressing the chipping of the tip portion and being able to obtain a good and stable cleaning performance over a long period of time can be exhibited remarkably.

  Accordingly, in order to solve the above-described problem, the cleaning device according to the first aspect of the present invention includes a cleaning member fixed to a cleaning member support provided so as to be swingable about a support shaft. In the cleaning device formed by pressing and abutting against the surface at an acute angle, the image carrier is in contact with the tangent of the image carrier at a contact point where the tip of the cleaning member abuts on the surface of the image carrier. And the side on which the support shaft of the cleaning member support is located, and the side on which the support shaft of the cleaning member support exists on a normal line perpendicular to the tangent at the contact point. The side on which the cleaned surface of the image carrier is present is made different, and the front end of the cleaning member in contact with the image carrier is the end of the side on which the support shaft of the cleaning member support does not exist Characterized in that located become side.

  According to the second aspect of the present invention, in the cleaning device according to the first aspect, the cleaning member support has a bent portion parallel to the support shaft direction, and the bent angle of the bent portion is an obtuse angle. It is characterized by being.

  The image forming apparatus according to claim 3 includes at least an image carrier on which a toner image is carried and conveyed, a transfer device that transfers the toner image on the image carrier to a transfer medium, and a cleaning device. The cleaning device according to claim 1 or 2 is used as the cleaning device.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the image forming apparatus further comprises a charging device disposed in contact with or close to the surface of the image carrier.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the charging device includes a voltage applying device that applies a voltage having an AC component.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus according to the fourth or fifth aspect, wherein the surface of the image carrier is disposed at a position on the post-process side from the cleaning by the cleaning apparatus and on the pre-process side from the charging process by the charging apparatus. A protective layer forming apparatus for applying or adhering a protective component to the protective layer is disposed.

  According to the seventh aspect of the present invention, in the image forming apparatus according to any one of the third to sixth aspects, the circularity SR of the toner is a circularity SR = perimeter of a circle having the same area as the particle projection area / The circularity SR is 0.93 to 1.00 when the perimeter of the projected particle image is used.

  In the image forming apparatus according to any one of claims 3 to 7, the ratio (D4 / D1) of the weight average diameter (D4) to the number average diameter (D1) of the toner is 1. .00 to 1.40.

  The process cartridge according to claim 9 integrally includes at least an image carrier that has undergone a step of carrying a toner image and a cleaning device that removes toner remaining on the image carrier, and the cleaning device includes: The cleaning apparatus according to 1 or 2 is used.

  According to a tenth aspect of the present invention, in the process cartridge according to the ninth aspect, a charging device is provided which is disposed in contact with or close to the surface of the image carrier.

  According to the eleventh aspect of the present invention, in the process cartridge according to the tenth aspect, the surface of the image carrier is disposed at a position on the post-process side after the cleaning by the cleaning device and on the pre-process side of the charging step by the charging device. A protective layer forming device for applying or adhering a protective component is provided.

  According to the twelfth aspect of the present invention, in the process cartridge according to any one of the ninth to eleventh aspects, a container for storing toner is provided, and the circularity SR of the toner is the same as the circularity SR = particle projected area. The circularity SR is 0.93 to 1.00, where perimeter of area circle / perimeter of particle projection image.

  According to the thirteenth aspect, in the process cartridge according to any one of the ninth to twelfth aspects, the ratio (D4 / D1) of the weight average diameter (D4) to the number average diameter (D1) of the toner is 1. It is 00 to 1.40.

  The present invention can stably exhibit a sufficient cleaning performance of the surface of the image carrier, and can stably obtain an image of good quality.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings. In the following,

  FIG. 1 is a cross-sectional view for schematically explaining the configuration of an embodiment of the cleaning apparatus of the present invention. The cleaning device 20 disposed opposite to the photosensitive drum 1 as an image carrier is mainly composed of a support shaft 21 of a cleaning member, a cleaning member support 22, a cleaning member 23, a pressing force applying mechanism 24, and the like. The The surface of the photosensitive drum 1 as an image carrier is in contact with the surface of the photosensitive drum 1 at the position of the contact point Q of the cleaning member 23 with respect to the photosensitive drum 1, and the tangent line of the surface of the photosensitive drum 1 at this contact point Q is L1. A straight line perpendicular to the tangent line L1 at the contact point Q is a normal line L2.

  The photosensitive drum 1 serving as an image carrier has a surface 1b on which toner components and the like remain after the transfer process. However, the surface residue is cleaned by the cleaning member 23 at the contact Q, and the cleaned surface 1a. It becomes.

  In the configuration of this embodiment, the cleaning member 23 is abutted at an angle similar to a so-called counter type (leading type) so that the image carrier surface of the tangent line L1 has an acute angle. Except for the case of Patent Document 4 (see FIG. 4), the support shaft 21 is generally located above the tangent line L1 and to the left side of the normal line L2 in FIG. . On the other hand, in the cleaning apparatus of the present embodiment, the support shaft 21 is configured to be located above the tangent line L1 and to the right side from the normal line L2, that is, within the range of the region A in FIG.

  By setting the position of the support shaft 21 in the range of the region A, the component force in the tangential L1 direction of the force acting on the cleaning member 23 when the photosensitive drum 1 as the image carrier is stationary, and the photosensitive drum 1 The component force in the tangential L1 direction of the force acting on the cleaning member 23 during driving becomes a vector in the same direction, and sudden direction change of the acting force at the tip of the cleaning member 23 is eliminated. For this reason, it is possible to eliminate problems such as chipping of the tip due to long-term use.

  Further, in the cleaning device of the present embodiment, the support shaft 21 is located on the side different from the photosensitive drum 1 with respect to the tangent L1, and therefore the direction of the pressing force that the cleaning member 23 presses the photosensitive drum 1 at the force point P. Can be set widely. That is, the component force component in the tangential L1 direction that is related to the amount of peeling and repulsion of the cleaning member 23 and the component component in the normal L2 direction that is related to the adhesion of the cleaning member 23 are within appropriate ranges. It can be set without structural restrictions.

  Further, by setting the position of the support shaft 21 within the range of the configuration of the present embodiment, the dynamic friction coefficient on the surface of the photosensitive drum 1 varies and the dynamic friction force increases, so that the vertical drag component of the pressing force at the contact point Q decreases. As a result, it is possible to highly suppress the peeling at the tip of the cleaning member 23.

  In the cleaning device of this embodiment, the tip of the cleaning member 23 that contacts the image carrier 1 at the contact point Q is located on a different side from the end of the cleaning member support 22 that does not have a support shaft. Since the arrangement of the cleaning member 23 and the support shaft 21 can be easily configured with a small number of parts, this is advantageous in terms of cost.

  FIG. 2 shows a modification of the cleaning device according to the present invention having a configuration similar to that of the embodiment of FIG. In the embodiment shown in FIG. 1, since there is an acute bent portion 22a in the middle of the cleaning member support 22, there is a risk of stress concentration at this point. Since the member support 22 does not have such an acute bent portion, the force applied to the cleaning member support 22 is evenly distributed, local distortion can be suppressed, and deterioration in cleaning performance can be prevented.

FIG. 3 shows the balance of force when the image carrier is stationary in the cleaning device of the embodiment of the present invention. The force F0 applied at the force point P is a pressing force F1 = in the direction perpendicular to the auxiliary line OQ at the contact point Q between the cleaning member 23 and the photosensitive drum 1 as the image carrier with the center of the support shaft 21 as the support point O. Acts as F0 · (OP / OQ). This F1 is divided into a tangential direction component and a normal direction component at the point Q using the angle θ formed by the tangent line L1 and the auxiliary line OQ shown in FIG.
F1 ・ sinθ
F1 ・ cosθ
It can be expressed as. That is, the force acting at the contact point Q is balanced by taking into account the portion of the cleaning member 23 that is deformed and accumulated as strain stress and the static frictional force at the contact point. As shown in FIG. 3, since the tangential direction component is an acting force that pushes the photosensitive drum 1 that is an image carrier in the right direction in the figure, the cleaning member 23 receives a leftward force in the figure as the reaction. In addition, when the photosensitive drum 1 as an image carrier is driven, the contact between the cleaning member 23 and the photosensitive drum 1 is slightly shifted to Q ′, and the same force balance as in FIG. 3 is maintained. Be drunk. However, at this time, the frictional force becomes a dynamic frictional force (FIG. 4). Also in FIG. 4, the tangential direction component is an acting force that pushes the photosensitive drum 1 rightward in the figure, and therefore the cleaning member receives a leftward force in the figure as its reaction.

On the other hand, FIG. 5 shows the balance of force when the photosensitive drum 1 which is an image carrier in a conventional counter type cleaning apparatus is stationary. The force F0 applied at the force point P is the pressing force F1 = F0 · (OP / OQ) in the direction perpendicular to the auxiliary line OQ at the contact point Q between the cleaning member and the photosensitive drum 1 with the center of the support shaft as the support point O. Acts as This F1 is divided into a tangential direction component and a normal direction component at the point Q using the angle θ formed by the tangent line L1 and the auxiliary line OQ shown in FIG.
F1 ・ sinθ
F1 ・ cosθ
It can be expressed as. That is, the force acting at the contact point Q is balanced in consideration of the portion of the cleaning member that is deformed and accumulated as strain stress and the static frictional force at the contact point. As shown in FIG. 5, the tangential direction component is an acting force that pushes the photosensitive drum 1 that is an image carrier leftward in the figure, so that the cleaning member 23 receives a rightward force in the figure as its reaction. . Further, even when the photosensitive drum 1 is driven by a conventional counter type cleaning device, the contact point between the cleaning member 23 and the photosensitive drum 1 is slightly shifted to Q ′. Since the force that pushes the photosensitive drum 1 in the right direction works, the cleaning member receives a leftward force in the figure as a reaction (FIG. 6).

  As described above, in the cleaning device having the configuration of the present invention, it is possible to eliminate the reversal of the tangential force at the front end portion of the cleaning member, which occurs in the conventional counter type cleaning device.

  Also, the angle formed by the tangent L1 extending to the uncleaned side of the front end surface of the cleaning member 23 and the surface of the photosensitive drum 1, the so-called cleaning angle is preferably 70 degrees or more and less than 90 degrees, and preferably 80 degrees or more and 90 degrees. More preferably, it is less than a degree. As is generally known, when the cleaning angle is reduced, the cleaning performance is deteriorated. In particular, as described above, in the cleaning device configured to decrease the vertical drag as the dynamic friction force increases, In order to maintain the cleaning performance, it is preferable to sufficiently increase the cleaning angle.

  Although the cleaning angle can be set by shifting the position of the support shaft, in this case, it is difficult to set the support shaft angle and the cleaning angle independently. Therefore, it is preferable that the cleaning member support 22 has a bent portion parallel to the axial direction of the support shaft and the bend angle is an obtuse angle, whereby the support shaft angle and the cleaning angle can be individually set. Become.

  Further, the cleaning member 23 preferably has a rebound resilience of 30% or more, and more preferably 40% or more. If the resilience is too small, the cleaning angle tends to be substantially reduced because the tip end of the cleaning member tends to be stable. In such a case, the cleaning performance is likely to deteriorate, and a larger pressing force is applied to the cleaning member, so that the stress on the surface of the image carrier may be increased.

  The material of the cleaning member 23 is not particularly limited, but elastic materials such as urethane rubber, hydrin rubber, silicone rubber, and fluoro rubber, which are generally known as cleaning blade materials, may be used alone or in combination. it can. Further, these rubber blades may be coated or impregnated with a low friction coefficient material at the contact portion with the image carrier. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

  Further, these cleaning blades are fixed to the cleaning member support 22 by an arbitrary method such as adhesion or fusion so that the front end portion can be pressed against the surface of the photosensitive drum 1 as an image carrier. The thickness of the cleaning blade cannot be uniquely defined in consideration of the force applied by pressing, but is preferably about 0.5 to 10 mm, and more preferably about 2 to 5 mm. In addition, the length of the cleaning blade that protrudes from the cleaning member support 22 and can bend, that is, the so-called free length, is also unambiguously defined by the balance with the force applied by pressing in the same manner. If it is about 1-20 mm, it can be preferably used, and if it is about 2-10 mm, it can be used still more preferably.

  As another configuration of the cleaning member, a layer of resin, rubber, elastomer or the like is formed on the surface of an elastic metal blade such as a spring plate by a method such as coating or dipping via a coupling agent or a primer component as necessary. If necessary, thermosetting or the like may be performed, and if necessary, surface polishing or the like may be performed. The thickness of the elastic metal blade is preferably about 0.2 to 3 mm, more preferably about 0.3 to 1 mm. Moreover, in an elastic metal blade, in order to suppress the twist of a braid | blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment. As a material for forming the surface layer, fluorine resin such as PFA, PTFE, FEP, PVdF, silicone elastomer such as fluorine rubber, methylphenyl silicone elastomer, and the like can be used together with a filler, if necessary. It is not limited to this.

  The force with which the cleaning member 23 presses the image carrier is preferably 5 gf / cm or more and 60 gf / cm or less as a pressure per unit contact length of the cleaning member 23, so-called linear pressure is preferably 10 gf / cm or more and 50 gf. / Cm or less is more preferable.

  FIG. 7 is a cross-sectional view showing an example of an image forming apparatus to be provided with the cleaning device of the present invention. In the illustrated image forming apparatus 100, an image forming apparatus 10 has a charging device 2, a latent image forming device 3, a developing device 4, a transfer device 5, and the like around a photosensitive drum 1 (1 </ b> Y to 1 </ b> K) that is an image carrier. The cleaning device 20 is disposed, and image formation is performed by the following operation.

  A series of processes for image formation will be described using a negative-positive process. An image carrier 1 typified by a photoreceptor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by a charging device 2 having a charging member. When the photosensitive drum 1 is charged by the charging device 2, an appropriate size suitable for charging the surface of the photosensitive drum 1 to a desired potential from a voltage application mechanism (not shown) to a charging member. Or a charging voltage obtained by superimposing an AC voltage thereon is applied. The charged photosensitive drum 1 forms a latent image with a laser beam irradiated by a latent image forming apparatus 3 such as a laser optical system (the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential). ) Is performed. Laser light is emitted from a semiconductor laser, and the surface of the photosensitive drum 1 is scanned in the direction of the rotational axis by a polygonal polygon mirror that rotates at high speed. The latent image formed in this way is developed with a developer made of toner particles or a mixture of toner particles and carrier particles supplied onto a developing sleeve, which is a developer carrying member in the developing device 4, and toner A visual image is formed. At the time of developing the latent image, a voltage of an appropriate magnitude between the exposed portion and the non-exposed portion of the photosensitive drum 1 or a development in which an AC voltage is superimposed on the developing sleeve from a voltage application mechanism (not shown). A bias is applied.

  The toner image formed on the photosensitive drum 1 corresponding to each color is transferred onto the intermediate transfer medium 60 by the transfer device 5 and transferred onto the transfer medium such as paper fed from the paper feeding mechanism 200. The image is transferred. At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer device 5 as a transfer bias. Thereafter, the intermediate transfer medium 60 is separated from the photosensitive drum 1, and a transfer image is obtained. The toner particles remaining on the photosensitive drum 1 are collected by the cleaning member 23 into the toner collecting chamber in the cleaning device 20.

  As the image forming apparatus, an apparatus in which a plurality of the developing devices described above are arranged is used, and a plurality of toner images, which are sequentially produced by the plurality of developing devices, are sequentially transferred onto a transfer material, and then sent to a fixing mechanism to be heated. Even after a plurality of toner images produced in the same manner are sequentially and sequentially transferred onto an intermediate transfer medium, and then collectively transferred to a transfer medium such as paper, Similarly, a fixing device may be used.

  The charging device 2 described above is preferably a charging device disposed in contact with or close to the surface of the image carrier, and thereby a corona discharge device called a corotron or a scorotron using a discharge wire. In comparison with the above, the amount of ozone generated during charging can be greatly suppressed. However, in a charging device that charges the charging member in contact with or close to the surface of the image carrier, the characteristics of the surface of the charging member tend to fluctuate due to the influence of the toner component that cannot be collected by the cleaning device 20. Since the cleaning device 20 of the present invention can maintain a stable cleaning performance for a long period of time, the above-described fluctuation of the surface of the charging member can be greatly suppressed, and stable charging over time, and thus stable image quality can be ensured. It becomes possible.

  Further, as described above, the characteristic variation of the charging member is mainly caused by contamination of the surface of the charging member due to a toner component or the like, and thus is easily caused when a voltage having an AC component is applied to the charging device. By using together with the apparatus, the toner component remaining on the image bearing member can be surely reduced, so that it is possible to achieve higher image quality by even charging and stabilization over time.

  In the image forming apparatus of the present invention, a protective layer forming apparatus for applying or adhering a protective component to the surface of the image bearing member is disposed in a step after the cleaning device as described above and a step before the charging device. Thus, deterioration due to external stress on the surface of the image carrier can be highly suppressed, and the life of the image carrier can be extended. The step of forming the protective layer is preferably performed immediately after the surface of the image carrier is cleaned by a cleaning device, thereby preventing the image from being subjected to electrical and mechanical stress in the subsequent charging step and developing step. The carrier can be efficiently protected, and the protective layer components that have deteriorated or deteriorated through these levels can be accurately cleaned and removed simultaneously with the removal of the residual toner by the cleaning device.

Next, the toner suitably used in the present invention will be described. First, the toner of the present invention preferably has an average circularity of 0.93 to 1.00. In the present invention, the value obtained from the following formula 1 is defined as circularity. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.
<Formula 1>
Circularity SR = The circumference of a circle having the same area as the particle projection area / the circumference of the particle projection image in the range of average circularity of 0.93 to 1.00, the surface of the toner particles is smooth, Since the contact area between the toner particles and the photoconductor is small, transferability is excellent. Since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated. Since there are no angular toner particles in the toner that forms the dots, when the pressure is brought into contact with the transfer medium during the transfer, the pressure is uniformly applied to the entire toner that forms the dots, and the transfer is not easily lost. Since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the image carrier is not damaged or worn.

  Next, a method for measuring the circularity will be described. The circularity can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics. As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been previously removed, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured by the above apparatus with the dispersion concentration being 3000 to 10000 / μl.

  In the present invention, the weight average diameter D4 of the toner is preferably 3 to 10 μm. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the weight average diameter D4 is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. When the weight average diameter D4 exceeds 10 μm, it is difficult to suppress scattering of characters and lines.

  In the toner of the present invention, the ratio of the weight average diameter D4 to the number average diameter D1 (D4 / D1) is preferably 1.00 to 1.40. The closer the value of (D4 / D1) is to 1, the sharper the particle size distribution of the toner. Therefore, when (D4 / D1) is in the range of 1.00 to 1.40, the selective development due to the toner particle size does not occur, and the stability of the image quality is excellent. Since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp, and fogging is suppressed. When the toner particle diameter is uniform, the latent image dots are developed so as to be arranged in a precise and orderly manner, so that the dot reproducibility is excellent.

Next, a method for measuring the particle size distribution of toner particles will be described. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below. First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measuring device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average diameter D4 and the number average diameter D1 of the toner can be obtained. As a channel,
Less than 2.00 to less than 2.52 μm 2.52 to less than 3.17 μm 3.17 to less than 4.00 μm 4.00 to less than 5.04 μm 5.04 to less than 6.35 μm 6.35 to less than 8.00 μm Less than 00 to less than 10.08 μm 10.08 to less than 12.70 μm 12.70 to less than 16.00 μm 16.00 to less than 20.20 μm 20.20 to less than 25.40 μm 25.40 to less than 32.00 μm 32.00 13 channels of less than 40.30 μm are used, and particles with a particle size of 2.00 μm or more and less than 40.30 μm are targeted.

  In addition, as such a substantially spherical toner, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of fine resin particles. A toner that undergoes crosslinking and / or elongation reaction is preferred. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

  Examples of the prepolymer comprising a modified polyester resin that can be used for toner preparation include a polyester prepolymer (A) having an isocyanate group, and examples of a compound that extends or crosslinks with the prepolymer include amines (B). Can be mentioned. Examples of the polyester prepolymer (A) having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate (3), which is a polycondensate of polyol 1 and polycarboxylic acid 2. Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferred. Examples of the polyol 1 include a diol (1-1) and a tri- or higher valent polyol (1-2), and (1-1) alone or a mixture of (1-1) and a small amount of (1-2). preferable.

  Diol (1-1) includes alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the alicyclic diol; bisphenol And alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use.

  The trihydric or higher polyol (1-2) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols. Examples of polycarboxylic acid 2 include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). (2-1) alone and (2-1) and a small amount of (2- The mixture of 2) is preferred. Dicarboxylic acid (2-1) includes alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms.

  Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). In addition, as polycarboxylic acid 2, you may make it react with polyol 1 using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing. The ratio of the polyol 1 and the polycarboxylic acid 2 is usually 2/1 to 1/1, preferably 1.5 / 1 to 1 as an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates such as phenol derivatives, oximes, caprolactams, etc. And a combination of two or more of these. The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, preferably 4 /, as the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. It is. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates. The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1-B5 blocked (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds). The ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester (i) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated. By these reactions, the modified polyester used in the toner of the present invention, especially the urea-modified polyester (i) can be prepared. These urea-modified polyesters (i) are produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  In the present invention, not only the polyester (i) modified with a urea bond but also the polyester (ii) not modified can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and glossiness when used in a full-color apparatus are improved, which is preferable to single use. Examples of (ii) include the same polycondensates of polyol 1 and polycarboxylic acid 2 as those of the polyester component (i), and preferred ones are also the same as (i). (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) and (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The peak molecular weight of (ii) is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 1-30, preferably 5-20. By having an acid value, it tends to be negatively charged.

In the present invention, the glass transition point (Tg) of the binder resin is usually 50 to 70 ° C., preferably 55 to 65 ° C. If it is less than 50 ° C., the blocking of the toner during high temperature storage deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners. As the storage elastic modulus of the binder resin, the temperature (TG ′) at which the measurement frequency is 20 Hz is 10000 dyne / cm ² is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the binder resin, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or lower, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, from the viewpoint of achieving both low temperature fixability and hot offset resistance, TG ′ is preferably higher than Tη. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or higher. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

  The binder resin can be produced by the following method. Polyol 1 and polycarboxylic acid 2 are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxy titanate, dibutyltin oxide, etc., and the generated water is distilled off under reduced pressure as necessary to remove the hydroxyl group. A polyester having is obtained. Next, this is reacted with polyisocyanate (3) at 40 to 140 ° C. to obtain a prepolymer (A) having an isocyanate group. Further, (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester modified with a urea bond. When (3) is reacted and (A) and (B) are reacted, a solvent can be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to the isocyanate (3), such as tetrahydrofuran (such as tetrahydrofuran). When polyester (ii) not modified with urea bond is used in combination, (ii) is produced by the same method as polyester having a hydroxyl group, and this is dissolved in the solution after completion of the reaction of (i) and mixed. To do.

  In addition, the toner used in the present invention can be produced generally by the following method, but is not limited thereto.

  The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  The toner particles may be formed by reacting a dispersion composed of a prepolymer (A) having an isocyanate group in an aqueous medium with (B), or using a urea-modified polyester (i) produced in advance. good. As a method for stably forming a dispersion comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium, a toner raw material comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force. The prepolymer (A) and other toner compositions (hereinafter referred to as toner raw materials), a colorant masterbatch, a release agent, a charge control agent, an unmodified polyester resin, etc. are dispersed in an aqueous medium. It may be mixed at the time of formation, but it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, but after the particles are formed. , May be added. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method. The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion made of urea-modified polyester (i) or prepolymer (A) has a low viscosity and is easy to disperse.

  The amount of the aqueous medium used relative to 100 parts of the toner composition containing the urea-modified polyester (i) and the prepolymer (A) is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable. In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner composition is dispersed in the aqueous medium, or may be dispersed in the aqueous medium. An amine (B) may be added later to cause a reaction from the particle interface. In this case, urea-modified polyester is preferentially produced on the surface of the manufactured toner, and a concentration gradient can be provided inside the particles.

  Anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphates, etc., alkylamines as dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water Amine salts such as salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, etc. Nonionic surfactants such as quaternary ammonium salt type cationic surfactants, fatty acid amide derivatives, polyhydric alcohol derivatives, such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl N, amphoteric surfactants such as N- dimethyl ammonium betaine.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Examples of the anionic surfactant having a fluoroalkyl group preferably used include fluoroalkylcarboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6- C11) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) mono-N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) Carboxylic acid and metal salt, perfluoroalkylcarboxylic acid (C7 to C13) and its metal salt, perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, perfluorooctanesulfonic acid diethanolamide, N-propyl- N- (2hydroxyethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Product names include: Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101, DS-102 (Daikin Kogyo Co., Ltd.), MegaFuck F-l10, F-l20, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), EX Top EF-102, 103, 104, 105, 112, 123A, 123B, 306 A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Examples of cationic surfactants include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, benza Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) , Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), and the like.

  Further, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant which is hardly soluble in water.

  Further, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, acrylate 3- Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or esters of compounds containing vinyl alcohol and carboxyl groups For example, pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine Homopolymers or copolymers such as those having a nitrogen atom or its heterocyclic ring, polyoxyethylene, polyoxypropylene, Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation.

  When a dispersant is used, the dispersant may remain on the surface of the toner particles, but it is preferable from the charged surface of the toner that the dispersant is washed and removed after the elongation and / or crosslinking reaction.

  Furthermore, in order to lower the viscosity of the toner composition, a solvent in which the urea-modified polyester (i) or the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred, and aromatic solvents such as toluene and xylene are more preferred. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or cross-linking reaction time is selected depending on the reactivity of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. is there. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer, rotary kiln.

  When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution. In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet.

  The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

  By mixing the resulting dried toner powder with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or by giving mechanical impact force to the mixed powder By immobilizing and fusing on the surface, it is possible to prevent detachment of the foreign particles from the surface of the resulting composite particle.

  Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) has been modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar, etc.

  As the colorant used in the toner, pigments and dyes conventionally used as toner colorants can be used. Specifically, carbon black, lamp black, iron black, ultramarine, nigrosine dye, Aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, rose bengal and the like can be used alone or in combination.

  Furthermore, if necessary, in order to give the toner particles magnetic properties, magnetic components such as iron oxides such as ferrite, magnetite and maghemite, metals such as iron, cobalt and nickel, or alloys of these with other metals. May be contained alone or in combination in the toner particles. Moreover, these components can also be used / used together as a colorant component.

  The number average diameter of the colorant in the toner used in the present invention is desirably 0.5 μm or less, preferably 0.4 μm or less, more preferably 0.3 μm or less. When the number average diameter of the colorant in the toner is larger than 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained. A colorant having a fine particle diameter of less than 0.1 μm is sufficiently smaller than a half wavelength of visible light, and thus is considered not to adversely affect light reflection and absorption characteristics. Therefore, the colorant particles of less than 0.1 μm contribute to good color reproducibility and transparency of the OHP sheet having a fixed image. On the other hand, if there are many colorants having a particle size larger than 0.5 μm, the transmission of incident light is hindered or scattered, and the brightness and color of the projected image of the OHP sheet tend to decrease. There is. Further, if there are many colorants having a particle size larger than 0.5 μm, the colorant is detached from the surface of the toner particles, and various problems such as fogging, drum contamination, and poor cleaning are liable to occur. In particular, the colorant having a particle size larger than 0.7 μm is preferably 10% by number or less, more preferably 5% by number or less of the total colorant.

  Also, by mixing the colorant together with part or all of the binder resin in advance after adding a wetting liquid, the binder resin and the colorant are initially sufficiently adhered, In the toner production process, the colorant is dispersed more effectively in the toner particles, the dispersed particle diameter of the colorant is reduced, and better transparency can be obtained. As the binder resin used for kneading in advance, the resins exemplified as the binder resin for toner can be used as they are, but are not limited thereto.

  As a specific method for kneading the mixture of the binder resin and the colorant with the wetting liquid in advance, for example, the binder resin, the colorant and the wetting liquid are obtained after mixing with a blender such as a Henschel mixer. The obtained mixture is kneaded at a temperature lower than the melting temperature of the binder resin by a kneader such as a two-roll or three-roll to obtain a sample.

  In addition, as the wetting liquid, a general one can be used in consideration of the solubility of the binder resin and the paintability with the colorant, but in particular, an organic solvent such as acetone, toluene, butanone, or water, It is preferable from the viewpoint of dispersibility of the colorant. Among these, the use of water is more preferable from the viewpoint of environmental considerations and maintaining the dispersion stability of the colorant in the subsequent toner production process. According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is further improved. Get better.

  In addition, as long as the configuration of the present invention is adopted, a release agent represented by wax can be contained in the toner together with the binder resin and the colorant. Known release agents can be used, such as polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sazol wax, etc.); carbonyl group-containing wax, etc. . Of these, carbonyl group-containing waxes are preferred. Carbonyl group-containing waxes include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecandiol diol distearate, etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylene diamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearyl amide, etc.) And dialkyl ketones (such as distearyl ketone). Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of these release agents is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset when fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight. In addition, a charge control agent may be contained in the toner as necessary in order to accelerate the toner charge amount and its rise.

  Here, since a color change occurs when a colored material is used as the charge control agent, a material that is colorless and close to white is preferable. Any known charge control agent can be used. Examples include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkyls. Amide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron P-51 of a quaternary ammonium salt, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex, E-89 of a phenol condensate (above, Orient Chemical Industry Co., Ltd.) Manufactured), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), copy charge PSY VP2038 of quaternary ammonium salt, copy blue PR of triphenylmethane derivative, Quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (from Hoechst), LRA-901, boron complex LR-147 (Nihon Carlit), quinacridone, azo pigment, other sulfonic acid groups , A polymer having a functional group such as a carboxyl group or a quaternary ammonium salt. Compounds. In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, or may be added when directly dissolving and dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. Also good.

  Further, when the toner composition is dispersed in the aqueous medium during the toner production process, resin fine particles mainly for stabilizing the dispersion may be added. The resin fine particles used may be any resin that can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resins, polyurethane resins, epoxy resins, polyester resins, Examples thereof include polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. As the resin fine particles, two or more of the above resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.

The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include, but are not limited to, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like. Further, inorganic fine particles can be preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

  Other polymer fine particles such as polystyrene, methacrylic acid ester and acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, polycondensation systems such as silicone, benzoguanamine, and nylon, and thermosetting resins Examples include polymer particles. Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  Examples of the cleaning property improver for removing the developer after transfer remaining on the photosensitive member or the primary transfer medium include fatty acid metal salts such as zinc stearate, calcium stearate and stearic acid, such as polymethyl methacrylate fine particles, polystyrene. Examples thereof include fine polymer particles produced by soap-free emulsion polymerization of fine particles and the like. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  By using these toners, a high-quality toner image having excellent development stability can be formed as described above. However, the toner that is not transferred to the transfer medium or intermediate transfer medium by the transfer device and remains on the image carrier is difficult to remove by the cleaning device due to its fineness and good rolling properties. May end up. In order to completely remove the toner from the image carrier, it is necessary to strongly press a toner removing member such as a cleaning blade against the image carrier. Such a load not only shortens the life of the image carrier and the cleaning device, but also uses extra energy. When the load on the image carrier is reduced, the toner and the small-diameter carrier on the image carrier are insufficiently removed, and these damage the surface of the image carrier when passing through the cleaning device. It becomes a factor which fluctuates performance.

  As described above, the image forming apparatus of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, particularly the presence of a low-resistance portion, and highly suppresses fluctuations in charging performance to the image carrier. Because of the configuration, when used in combination with the toner having the above configuration, an extremely high quality image can be stably obtained over a long period of time.

  In addition, the image forming apparatus of the present invention can be applied not only to the use of the toner having a configuration suitable for obtaining a high quality image as described above, but also to an irregular shaped toner by a pulverization method, and the life of the apparatus. Needless to say, it will be greatly extended.

  As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation. Examples of general binder resins used in the toner include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and the like; styrene / p-chlorostyrene copolymers; Styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, Styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / Acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer, Styrene copolymers such as tylene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate, etc. Acrylic ester-based homopolymers and copolymers thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester-based polymers, polyurethane-based polymers, polyamide-based polymers, polyimide-based polymers, polyol-based polymers, Examples thereof include an epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, and the like. These can be used alone or in combination, but are not particularly limited thereto. Among these, at least one selected from styrene-acrylic copolymer resins, polyester resins, and polyol resins is more preferable from the viewpoint of electrical characteristics, cost, and the like. Furthermore, it is more preferable to use a polyester-based resin and / or a polyol-based resin as having good fixing characteristics.

  For the reasons described above, the same resin component as the binder resin of the toner contained in the coating layer of the charging member includes a linear polyester resin composition, a linear polyol resin composition, and a linear styrene acrylic resin. At least one of the compositions or these cross-linked products can be preferably used. In the pulverized toner, together with these resin components, the colorant component, wax component, charge control component, and the like as described above are premixed as necessary, and then kneaded at a temperature close to the melting temperature of the resin component, and then cooled. Thereafter, a toner may be prepared through a pulverization and classification step, and the above-mentioned external additive components may be appropriately added and mixed as necessary.

  Similarly, by using the cleaning device of the present invention and the carrier and toner as described above in the process cartridge, the lifetime of the parts in use can be greatly extended, so the environmental load is easily reduced. be able to.

  Next, an example of the process cartridge according to the present invention will be described. FIG. 8 illustrates a process cartridge, an intermediate transfer medium 60, and a primary transfer device 61, each including a photosensitive drum 1, which is an image carrier, a charging device 2, a developing device 4, and a cleaning device 20. In the case of the process cartridge, similarly to the image forming apparatus, when the image carrier is charged by the charging device 2, the photosensitive drum 1 as the image carrier is transferred from the voltage application mechanism (not shown) to the charging member. A voltage of an appropriate magnitude suitable for charging the battery to a desired potential or a charging voltage obtained by superimposing an AC voltage thereon is applied. The charged photosensitive drum 1 forms a latent image with a laser beam irradiated by a latent image forming apparatus 3 such as a laser optical system (the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential). ) Is performed. Laser light is emitted from a semiconductor laser, and the surface of the photosensitive drum 1 is scanned in the direction of the rotational axis of the photosensitive drum 1 by a polygonal polygonal mirror (polygon) that rotates at high speed.

  The latent image formed in this manner is developed with a developer made of toner particles or a mixture of toner particles and carrier particles supplied onto a developing sleeve 5a which is a developer carrying member in the developing device 4, and the toner A visible image is formed. At the time of developing the latent image, a voltage of an appropriate magnitude between the exposed portion and the non-exposed portion of the photosensitive drum 1 or a development in which an AC voltage is superimposed on the developing sleeve from a voltage application mechanism (not shown). A bias is applied. The toner image formed on the photosensitive drum 1 is transferred onto the intermediate transfer medium 60 by the primary transfer device 61. At this time, it is preferable that a potential having a polarity opposite to that of toner charging is applied to the primary transfer device 61 as a transfer bias. Thereafter, the intermediate transfer medium 60 is separated from the photosensitive drum 1, and a transfer image is obtained.

  In addition, the toner particles remaining on the photosensitive drum 1 are collected by the cleaning member 23 into the toner collecting chamber 25 in the cleaning device 20.

  Examples of the present invention will be described in detail below with reference to experimental examples, but the present invention is not limited to the following examples and experimental examples.

<Experimental example 1>
A support shaft is joined to one end of a stainless steel plate having a thickness of 1.5 mm, a width of 22 mm, and a length of 330 mm, and is bent at a position of 12.2 mm from the center of the support shaft at a bending angle of 131 degrees over the entire length. A cleaning member support was prepared. Schematic diagrams are shown in FIGS. 9 (a) and 9 (b).

  A urethane rubber blade with a rebound resilience = 70%, formed into a rectangular plate with a thickness = 2 mm, a width = 10 mm, and a length = 320 mm, is used as a cleaning member 23, and the tip of the cleaning member support 22 has no support shaft 21 side. The substrate was bonded to the cleaning member support 22 so that the free length = 2 mm to the side different from the end of the cleaning member. (FIG. 9 (b)) Also, a support shaft angle (an angle formed by a tangent line on the cleaned surface side of the photosensitive drum 1, which is an image carrier at the contact point, and a line segment connecting the contact point and the center of the support shaft 21) = The position of the support shaft 21 was adjusted to be 150 degrees. A load was applied so that the pressing force was 35 gf / cm, and the cleaning angle was measured to be 75 degrees. With the above settings, a cleaning device (C1) that can be mounted on a color MFP (trade name: imagio Neo C455) manufactured by Ricoh Co., Ltd. was created.

  Then, using the remodeling machine of color MFP (trade name: imagio Neo C455) manufactured by Ricoh Co., Ltd., the above-mentioned cleaning device (C1) is installed in the image forming unit, and A4 size, 6% image area ratio of 400,000 originals An image drawing test was conducted to confirm the presence or absence of image abnormality before and after the test.

  At this time, a toner prepared by a polymerization method having a weight average diameter (D4) = 5.2 μm, a number average diameter (D1) = 4.5 μm, and a circularity SR = 0.98 was used as a test toner.

As image abnormalities, streak-like image defects and fogging of the background portion related to the quality of the cleaning performance were evaluated. Further, in order to evaluate the magnitude of the influence of the deterioration of the photosensitive drum 1 as the image carrier, the cleaning member 23 as the cleaning blade, and the charging member on the image, at the time of 100,000 sheets, 200,000 sheets, and 400,000 sheets. Each state of was observed and the presence or absence of abnormality was confirmed. In each member, there was no deterioration as the number of printed sheets increased, and good image quality was obtained both at the initial stage and after 400,000 sheets. The cleaning device and the image forming apparatus of the present invention were improved in image quality and lifetime. It turned out to be useful on both sides. The evaluation results are shown in Tables 1 and 2.

<Experimental example 2>
The bending angle and the support shaft position of the cleaning member support were adjusted so that the support shaft angle = 170 degrees and the cleaning angle = 75 degrees, and the pressing force was set to 30 gf / cm. A test was conducted.

  The evaluation results are also shown in Tables 1 and 2 above.

<Experimental example 3>
The bending angle and the support shaft position of the cleaning member support 22 are adjusted so that the support shaft angle is 130 degrees and the cleaning angle is 75 degrees, and the pressing force is 40 gf / cm. The test was conducted. This is also shown in Tables 1 and 2 for each evaluation result.

<Experimental example 4>
A stainless plate having a thickness of 3.0 mm, a width of 17 mm, and a length of 330 mm was cut over the entire length so that a section having a width of 9 mm had a thickness of 1.5 mm. Thereafter, a support shaft was joined to the uncut surface side of the cut end, and a cleaning member support was prepared. A urethane rubber blade having a rebound resilience = 70%, formed into a rectangular parallelepiped plate shape having a thickness = 2 mm, a width = 10 mm, and a length = 320 mm, the tip of the cleaning member 23 in contact with the photosensitive drum 1 is the cleaning member support 22. The cleaning member support 22 was bonded to a side different from the end on the side where the support shaft 21 was not provided so that the free length = 2 mm. (FIG. 10). Further, the position of the support shaft was adjusted so that the support shaft angle (angle formed by the line connecting the contact point and the center of the support shaft with the tangent of the contact surface of the image carrier at the contact point) = 150 degrees. A load was applied so that the pressing force was 35 gf / cm, and the cleaning angle was measured to be 75 degrees. With the above settings, a cleaning device (C2) using a cleaning member support that conforms to Experimental Example 1 and has no bent portion in the middle was prepared.

  The test was performed in the same manner as in Experimental Example 1 except that the cleaning device (C2) was used. The evaluation results are shown in Tables 1 and 2.

<Experimental example 5>
The test was performed in the same manner as in Example 1 except that the urethane rubber blade had a rebound resilience = 65%. This is also shown in Tables 1 and 2 for each evaluation result.

<Comparative Example 1>
A support shaft is joined to one end of a stainless steel plate having a thickness of 1.5 mm, a width of 35 mm, and a length of 330 mm. The cleaning member is bent to a bending angle of 22 degrees at a position 25 mm from the center of the support shaft over the entire length. A support was made. A schematic diagram is shown in FIG. A urethane rubber blade having a rebound resilience = 70%, formed into a rectangular parallelepiped plate having a thickness = 2 mm, a width = 10 mm, and a length = 320 mm, is cleaned at the tip of the cleaning member 23 in contact with the photosensitive drum 1 serving as an image carrier. The member support 22 was bonded to the cleaning member support 22 to the same side as the end where the support shaft 21 is not present so that the free length = 2 mm (FIG. 11B). Further, the position of the support shaft was adjusted so that the support shaft angle (angle formed by the line connecting the contact point and the center of the support shaft with the tangent of the contact surface of the image carrier at the contact point) = 150 degrees. A load was applied so that the pressing force was 35 gf / cm, and the cleaning angle was measured to be 75 degrees. With the above settings, a cleaning device (C3) was created in which the setting conditions were the same as in Experimental Example 1 and only the support form of the cleaning member support was different.

  The test was performed in the same manner as in Experimental Example 1 except that the cleaning device (C3) was used. This is also shown in Tables 1 and 2 for each evaluation result.

<Comparative example 2>
A support shaft was joined to one end of a stainless steel plate having a thickness of 1.5 mm, a width of 22 mm, and a length of 330 mm to prepare a cleaning member support. A urethane rubber blade having a rebound resilience = 70%, formed into a rectangular parallelepiped plate having a thickness = 2 mm, a width = 10 mm, and a length = 320 mm, is cleaned at the tip of the cleaning member 23 in contact with the photosensitive drum 1 serving as an image carrier. The member support 22 was bonded to the cleaning member support 22 so as to have a free length = 2 mm to the same side as the end of the side where the support shaft 21 is not present (FIG. 12). Further, the position of the support shaft was adjusted so that the support shaft angle (the angle formed by the line connecting the contact surface and the center of the support shaft with the tangent of the contacted surface of the photosensitive drum 1 at the contact) = 27 degrees. A load was applied so that the pressing force was 35 gf / cm, and the cleaning angle was measured to be 75 degrees. With the above settings, a general cleaning device (C4) having a different spindle position from the present invention was created.

  A test was conducted in the same manner as in Experimental Example 1 except that the cleaning device (C4) was used. As a result, a blade crack occurred at the initial stage of the test, and the test could not withstand practical use.

  As is clear from the above description and the comparison between the experimental example and the comparative example, according to the cleaning device of the present invention, the direction of the component force of the pressing force in the tangential direction at the contact point between the cleaning member tip and the image carrier is Since the image bearing member does not change between when the image carrier is stationary and when it is driven, it is possible to prevent the cleaning member from undergoing a sudden change in the acting force, greatly extending the life of the member, and large bending in the cleaning member support. Since there is no portion where distortion is applied, the cleaning member can be stably supported over a long period of time. In addition, since it is easy to process parts, it is possible to configure a high-performance cleaning device at low cost.

  In addition, since the support shaft angle can be easily set to an arbitrary angle within the specified range in the present invention, individual component placement depending on the configuration of the image forming apparatus can be easily realized with high accuracy. Further, the surface of the image carrier can be stably and reliably cleaned, and the image carrier can be charged to a stable and uniform potential for an extremely long time, so that the initial image quality can be maintained without fluctuation. be able to. In addition, according to the image forming apparatus of the present invention, the initial high-quality image can be maintained without being changed over a long period of time by using in combination with a toner suitable for obtaining a high-quality image. According to the process cartridge of the present invention, the surface of the image carrier can be stably and reliably cleaned, and the image carrier can be charged to a stable and uniform potential for an extremely long time. The quality can be maintained without fluctuation, and the replacement interval of the process cartridge or the parts used in the process cartridge can be widened, thereby reducing waste and greatly reducing the load on the natural environment. be able to.

Sectional drawing for demonstrating schematically the structure of one Example of the cleaning apparatus of this invention The figure which shows the modification of the cleaning apparatus which concerns on this invention of the structure similar to the Example of FIG. The figure which shows the balance of force in the cleaning apparatus of an Example of this invention when an image carrier is stationary. The figure which shows the state from which a friction force turns into a dynamic friction force even if the balance of force similar to FIG. 3 is maintained. The figure which shows the balance of force when the photosensitive drum which is an image carrier in a conventional counter type cleaning device is stationary. The figure which shows the change of the force when the photosensitive drum which is an image carrier in the example of FIG. 5 rotates. Sectional drawing which shows an example of the image forming apparatus used as the object which comprises the cleaning apparatus of this invention The figure which shows the Example of the process cartridge which concerns on this invention The figure which shows Experimental example 1 which concerns on the Example of this invention. Diagram showing Experimental Example 4 The figure which shows the comparative example 1 with the experiment example which concerns on the Example of this invention. The figure which shows the comparative example 2 with the experiment example which concerns on the Example of this invention.

Explanation of symbols

1: Photosensitive drum 1b: Surface of the photosensitive drum where toner components remain 1a: Cleaned surface of the photosensitive drum 2: Charging device 3: Latent image forming device 4: Developing device 5: Transfer device 10: Image forming Device 20: Cleaning device 21: Cleaning member support shaft 22: Cleaning member support 22a: Bending portion of cleaning member support 23: Cleaning member 24: Pressurizing mechanism 25: Toner recovery chamber 60: Intermediate transfer medium 61: Primary Transfer device 100: Image forming apparatus 200: Paper feed mechanism Q: Contact point of cleaning member to photosensitive drum L1: Tangent line of photosensitive drum surface at contact Q L2: Normal line orthogonal to tangent L1 at contact Q P : Force point O: Support point (center of support shaft)
θ: angle formed by tangent L1 and auxiliary line OQ

Claims (13)

In the cleaning device, the cleaning member fixed to the cleaning member support provided so as to be swingable about the support shaft forms an acute angle with the surface to be cleaned of the image carrier and presses against the surface. The side on which the image carrier is present and the side on which the support shaft of the cleaning member support is different from the tangent of the image carrier at the contact point where the tip of the member abuts on the surface of the image carrier. And the normal side perpendicular to the tangent at the contact point is different from the side where the support shaft of the cleaning member support is located and the side where the cleaned surface of the image carrier is located, A cleaning device, wherein a front end of a cleaning member in contact with an image carrier is located on a side different from a terminal end of the cleaning member support on which no support shaft is provided. The cleaning device according to claim 1, wherein the cleaning member support has a bent portion parallel to the spindle direction, and the bent angle of the bent portion is an obtuse angle. An image forming apparatus comprising at least an image carrier on which a toner image is carried and conveyed, a transfer device that transfers the toner image on the image carrier to a transfer medium, and a cleaning device. An image forming apparatus comprising the cleaning device according to 2. The image forming apparatus according to claim 3, further comprising a charging device disposed in contact with or close to the surface of the image carrier. The image forming apparatus according to claim 4, wherein the charging device includes a voltage applying device that applies a voltage having an AC component. A protective layer forming device for applying or adhering a protective component to the surface of the image carrier is provided at a position after the cleaning step by the cleaning device and before the charging step by the charging device. The image forming apparatus according to claim 4, wherein the image forming apparatus is an image forming apparatus. The circularity SR of the toner is
The circularity SR is 0.93 to 1.00 when the circularity SR = peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image. The image forming apparatus according to claim 6. The image according to any one of claims 3 to 7, wherein a ratio (D4 / D1) of the weight average diameter (D4) and the number average diameter (D1) of the toner is 1.00 to 1.40. Forming equipment. An image carrier that has undergone at least a step of carrying a toner image and a cleaning device that removes toner remaining on the image carrier are integrally provided, and the cleaning device according to claim 1 or 2 is used for the cleaning device. A process cartridge characterized by comprising 10. The process cartridge according to claim 9, further comprising a charging device disposed in contact with or close to the surface of the image carrier. A protective layer forming device for applying or adhering a protective component to the surface of the image carrier is provided at a position after the cleaning step by the cleaning device and before the charging step by the charging device. The process cartridge according to claim 10. A container for containing toner, and the circularity SR of the toner,
The circularity SR is 0.93 to 1.00, where circularity SR = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image. The process cartridge according to any one of 11. 13. The process according to claim 9, wherein a ratio (D4 / D1) of the weight average diameter (D4) and the number average diameter (D1) of the toner is 1.00 to 1.40. cartridge.