JP5053767B2 - Image forming apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a fax machine, or a printer, and more specifically, an image forming apparatus having a cleaning device that abuts a cleaning blade on the surface of the object to be cleaned to clean the surface of the object to be cleaned. It is about.

An electrophotographic image forming apparatus includes a cleaning device for removing toner remaining on the surface of an image carrier after transfer and repeatedly using it for image formation. As the cleaning device in this image forming apparatus, a cleaning blade made of an elastic member such as polyurethane rubber is brought into contact with the surface of the image carrier, which is the object to be cleaned, because of its simple structure and excellent toner removal performance. It is common.
As a cleaning blade used in such a cleaning apparatus, a blade having a right-angle tip angle formed by two surfaces forming a ridge line of the cleaning blade in contact with the surface of the image carrier is generally used.

In the cleaning device described in Patent Document 1, unlike a general cleaning device, the tip angle formed by the two surfaces forming the ridgeline of the cleaning blade that contacts the surface of the image carrier has an obtuse angle.
In the cleaning blade having an obtuse tip shape, the reciprocating motion (stick-slip motion) of the blade tip caused by the surface movement of the image carrier is suppressed as compared with a cleaning blade having a right tip angle. For this reason, wear of the cleaning blade can be suppressed, and the life of the cleaning blade can be extended. Also, the edge of the cleaning blade is obtuse, and the blade contact portion in the state where the cleaning blade is in contact with the image carrier is less likely to deform around the ridge line in contact with the image carrier than in the case of a right angle. The contact width becomes smaller. Since the contact width of the blade contact portion is small, the peak pressure (surface pressure) at the blade contact portion should be increased even when the blade pressure is the same (pressing force) compared to the blade having a right angle. Can do. Therefore, even with the same blade linear pressure value, a cleaning blade having a blunt tip angle can achieve better cleaning performance than that having a right tip angle. For this reason, a cleaning blade with an obtuse tip angle is more advantageous than a tip with a right angle when cleaning toner with high circularity, which is difficult to remove by cleaning with a cleaning blade.

JP 2006-154747 A

However, the present inventors have discovered that a cleaning blade having an obtuse tip angle is more likely to allow foreign matters such as paper dust to be caught in the blade contact portion than that having a right tip angle. Specifically, after the image forming apparatus is running under the same conditions except that the shape of the tip angle of the cleaning blade that contacts the photoconductor as the image carrier is different, the cleaning blade is removed from the photoconductor to remove the blade contact portion. As a result of confirmation, it was confirmed that more foreign matters were attached to the obtuse-angled tip than the right-angled tip.
As described above, the following reason is presumed as the reason why the tip having an obtuse angle is more likely to insert foreign matter into the blade contact portion.
That is, when the elastic member is bent and deformed, its surface becomes hard and deformation due to pressing of the surface is less likely to occur, and as the amount of bending deformation of the elastic member increases, deformation of the surface due to pressing is less likely to occur. For this reason, the tip shape with an obtuse angle that hardly deforms around the ridge line in contact with the image carrier is more likely to be deformed by pressing the surface than the one with a right tip angle. Therefore, when the tip shape is obtuse, it is presumed that at the blade contact portion, the foreign matter deforms the surface of the cleaning blade and enters the blade contact portion, and the foreign matter is likely to be sandwiched between the blade contact portions. .
In addition, the obtuse-angled cleaning blade suppresses stick-slip motion at the blade tip as compared with a cleaning blade having a right-angled tip angle. Therefore, when a foreign matter such as paper dust is caught between the blade contact portions, it is difficult to blow off the foreign matter. Therefore, it is estimated that the foreign matter is likely to be caught between the blade contact portions.

  When the image formation is continued in a state where foreign matter is caught in the blade contact portion, the amount of foreign matter caught in the blade contact portion increases with time, and cleaning failure occurs.

  The present invention has been made in view of the above problems, and an object of the present invention is to use a cleaning blade having an obtuse tip angle in contact with the object to be cleaned, and stably clean the object to be cleaned over time. It is an object of the present invention to provide an image forming apparatus that can do this.

In order to achieve the above object, a first aspect of the present invention is a cleaning object that moves on the surface, and a cleaning device that cleans the surface of the cleaning object by bringing a cleaning blade into contact with the surface of the cleaning object. In an image forming apparatus that has an obtuse tip angle formed by two surfaces that form a ridge line of the cleaning blade that comes into contact with the object to be cleaned, the blade contact between the object to be cleaned and the cleaning blade have a foreign substance removing means for removing a jammed foreign substance part, the foreign matter removing means, the non-image toner which does not contribute to image formation at the time of non-image formation by adhering to the surface of the object to be cleaned body, non image toner a toner input control means for controlling input to said blade contact portion, said after the non-image toner is input to the blade contact portions, of the normal image formation of the object to be cleaned body The surface movement direction is to anda be cleaned surface movement control means for performing control to surface movement in the opposite direction.
Further, the invention of claim 2, the image forming apparatus according to claim 1, said toner input control means該被clean the non-image toner when the surface of the object to be cleaning element surfaced moved by a predetermined moving amount It is characterized by adhering to the surface of the body .
Also, the invention of claim 3, the image forming apparatus according to claim 1 or 2, the surface upstream side in the movement direction of the normal image formation of the object cleaning element relative to the blade contact portions, said A cleaning brush that contacts the surface of the object to be cleaned is provided.
The invention of claim 4 is claimed in claim 1, 2 or in the image forming apparatus 3, it is characterized in that the object to be cleaned body is the toner image bearing member.
The invention of claim 5 is, in claim 1, 2, 3 or the image forming apparatus 4, the toner used for imaging, characterized in that the circularity is 0.93 or more is there.
The invention of claim 6 is the image forming apparatus according to claim 1, 2, 3, 4 or 5, the toner used for image formation, the polyester prepolymer having a functional group containing a nitrogen atom, a polyester, It is a toner obtained by subjecting a toner composition containing a colorant and a release agent to at least one of a crosslinking and elongation reaction in the presence of resin particles in an aqueous medium.
The invention of claim 7, claim 1, 2, 3, 4, 5 or 6 image forming apparatus, and integrally supports at least the object cleaning element and the cleaning device, an image forming apparatus It has a unit device that can be attached to and detached from the main body.

In the image forming apparatus according to the first to seventh aspects, the foreign matter sandwiched between the blade contact portions can be removed by the foreign matter removing means.

According to the first to seventh aspects of the present invention, it is possible to prevent an increase in the amount of foreign matter sandwiched between the blade contact portions over time by removing the foreign matter sandwiched between the blade contact portions. Thereby, there is an excellent effect that it is possible to prevent the occurrence of poor cleaning due to foreign matters such as paper dust being caught in the blade contact portion.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic full-color printer (hereinafter referred to as a printer 100) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of the printer 100.
As shown in FIG. 1, four photoconductor units 2Y, 2M, 2C, and 2K are detachably attached to the apparatus main body 1 in a box-shaped apparatus main body 1 of the printer 100, respectively. A transfer belt 3 serving as a recording material carrier is disposed obliquely in the diagonal direction of the apparatus main body 1 at the center in the apparatus main body 1. The transfer belt 3 is provided so as to be able to be driven to rotate in the direction of an arrow A in the drawing, spanned by a plurality of rollers to which the rotational driving force is transmitted.

The photoconductor units 2Y, 2M, 2C, and 2K have drum-like photoconductors 4Y, 4M, 4C, and 4K as image carriers, and transfer belts such that the surface of each photoconductor 4 is in contact with the transfer belt 3. 3 is disposed above. In addition, four transfer brushes 57Y, 57M, 57C, and 57K are provided on the inner side of the transfer belt 3 so as to face the four photoconductors 4Y, 4M, 4C, and 4K with the transfer belt 3 interposed therebetween. Yes.
The arrangement of the photoreceptor units 2Y, 2M, 2C, and 2K is in the order of 2Y, 2M, 2C, and 2K so that the photoreceptor unit 2Y is located on the paper feed side and the photoreceptor unit 2K is located on the fixing device 9 side. Yes. As the photoconductors 4Y, 4M, 4C, and 4K, belt-like photoconductors or the like may be used.

In each of the photoconductor units 2Y, 2M, 2C, and 2K, developing devices 5Y, 5M, 5C, and 5K that use different colors are arranged to face the photoconductors 4Y, 4M, 4C, and 4K, respectively. The developing devices 5Y, 5M, 5C, and 5K are two-component developing type developing devices that have substantially the same overall configuration and that differ only in the color of the toner that is used.
For example, the developing device 5Y accommodates a two-component developer having yellow (hereinafter referred to as “Y”) toner and a carrier, supplies Y toner to the electrostatic latent image on the photoreceptor 4Y, and develops it. The developing device 5M accommodates a two-component developer having magenta (hereinafter referred to as M) toner and a carrier, and supplies M toner to the electrostatic latent image on the photoreceptor 4M for development. The developing device 5C contains a two-component developer having cyan (hereinafter referred to as C) toner and a carrier, and supplies C toner to the electrostatic latent image on the photoreceptor 4C for development. The developing device 5K contains a two-component developer having black (hereinafter referred to as K) toner and a carrier, supplies K toner to the electrostatic latent image on the photoreceptor 4K, and develops it.

  Each of the developing devices 5Y, 5M, 5C, and 5K includes a developing roller that faces the photoreceptors 4Y, 4M, 4C, and 4K, an agitating and conveying screw that conveys and agitates the two-component developer, and a toner concentration of the two-component developer that is accommodated. A toner concentration sensor for detecting The developing roller is composed of an outer rotatable sleeve and a magnet roller fixed on the inner side. Further, according to the output of the toner density sensor, toner is supplied to the two-component developer in the developing device 5 by a toner supply device (not shown).

A writing unit 6 as an exposure unit is disposed above the photoreceptor units 2Y, 2M, 2C, and 2K, and a duplex unit 7 is disposed below the photoreceptor units 2Y, 2M, 2C, and 2K. Below the duplex unit 7, paper feed cassettes 13 and 14 that can store transfer paper P having different sizes in two upper and lower stages are arranged.
On the left side of the apparatus main body 1 of the printer 100, there is disposed a reversing unit 8 for reversing and discharging the transfer paper P after image formation, and for transporting the transfer paper P after image formation to the duplex unit 7. . A manual feed tray 15 is provided on the right side of the apparatus main body 1 of the printer 100 so as to be opened and closed in the direction of arrow B. By opening the manual feed tray 15, manual feed can be performed from the manual feed tray 15.
A fixing device 9 is disposed between the transfer belt 3 and the reversing unit 8. A reverse conveyance path 10 is branched and formed on the downstream side of the fixing device 9 in the transfer sheet conveyance direction. The reverse conveyance path 10 enables the transfer paper P to be discharged onto a paper discharge tray 12 provided at the upper part of the apparatus by a pair of paper discharge rollers 11 disposed in the conveyance path.

  The photoreceptor units 2Y, 2M, 2C, and 2K are units for forming toner images of Y, M, C, and K colors on the photoreceptors 4Y, 4M, 4C, and 4K, and are disposed in the apparatus main body 1. The configuration is the same except for the location. Each of the photoreceptor units 2Y, 2M, 2C, and 2K has the same configuration and operation except that the toners stored in the developing devices 5Y, 5M, 5C, and 5K are different. The explanation will be made with subscripts omitted.

  FIG. 2 is a schematic configuration diagram showing the internal configuration of the photoconductor unit 2. The details of the photoconductor unit 2 will be described later. As shown in FIG. 2, the photoconductor unit 2 includes a photoconductor 4, a charging roller 20 that contacts the photoconductor 4, and a cleaning that cleans the surface of the photoconductor 4. Device 17. The photosensitive unit 2 as a unit device is detachably attached to the apparatus main body 1 as a process cartridge. The cleaning device 17 includes a brush roller 21 and a cleaning blade 47.

  The writing unit 6 is arranged in four laser diode (LD) light sources prepared for each color, a pair of polygon scanners composed of a six-sided polygon mirror and a polygon motor, and an optical path of each light source. Further, it is composed of a lens such as an fθ lens, a long WTL, or a mirror. Laser light emitted from the laser diode is deflected and scanned by a polygon scanner and irradiated onto the photosensitive member 4.

  The duplex unit 7 includes a pair of conveyance guide plates 45a and 45b and a plurality (four in this example) of conveyance roller pairs 46 that form a pair. In the double-sided image formation mode in which images are formed on both sides of the transfer paper P, the transfer paper P that has been formed on one side and conveyed to the reversal conveyance path 54 of the reversing unit 8 and conveyed switchback is received. Is transported toward the paper feed unit.

  The reversing unit 8 includes a plurality of paired transport rollers and a plurality of paired transport guide plates. Then, as described above, the transfer paper P for double-sided image formation is turned upside down and carried out to the double-sided unit 7, or the transfer paper P after image formation is discharged out of the machine in the same orientation, or the front and back sides are turned upside down. And let it work out of the machine. Separating paper feeding rollers 55 and 56 for separating and feeding the transfer paper P one by one are provided in the paper feeding unit in which the paper feeding cassettes 13 and 14 are provided.

Next, an operation at the time of full color image formation by the printer 100 as the image forming apparatus will be described.
In the printer 100, when an image formation is instructed by an operation unit (not shown) and the printer 100 receives full-color image data, each photoconductor 4 is rotated by a drive source (not shown) to rotate clockwise in FIG. Each charging roller 20 of each photoconductor unit 2 is charged with a charging bias from a power source (not shown) to uniformly charge each photoconductor 4. Each photoconductor 4 is uniformly charged by each charging roller 20 and then exposed to laser light modulated by image data of each color of Y, M, C, K in the writing unit 6. An electrostatic latent image corresponding to the image data of each color is formed on the surface 4. Specifically, the photoconductor 4Y of the photoconductor unit 2Y is irradiated with laser light corresponding to the yellow image by the writing unit 6, and the photoconductor 4M of the photoconductor unit 2M is irradiated with a magenta image by the writing unit 6. The laser beam corresponding to is irradiated. The photoconductor 4C of the photoconductor unit 2C is irradiated with laser light corresponding to the cyan image by the writing unit 6, and the photoconductor 4K of the photoconductor unit 2K is converted to a black image by the writing unit 6. Corresponding laser light is irradiated.
Each electrostatic latent image formed on each photoconductor 4 reaches a developing area at a position facing the developing devices 5Y, 5M, 5C, and 5K, respectively, as the photoconductor 4 rotates. Each electrostatic latent image that has reached the development area is developed with yellow, magenta, cyan, and black toners of the developing devices 5Y, 5M, 5C, and 5K, and Y, M, C, and K are developed on the respective photoreceptors 4. A toner image of each color is obtained.

  On the other hand, one transfer sheet P is separated from the selected one of the sheet cassettes 13 and 14 by the separation sheet feeding roller 55 or 56, and is closer to the sheet feeding side than the photosensitive unit 2Y. The paper is fed to the registered registration roller pair 51. In the present embodiment, a manual feed tray 15 is disposed on the right side of the apparatus main body 1, and the transfer paper P can be fed from the manual feed tray 15 to the registration roller pair 51. The registration roller pair 51 sends the transfer paper P onto the transfer belt 3 at a timing when the leading edge of the transfer paper P coincides with the toner image on the photoconductors 4Y, 4M, 4C, and 4K. The fed transfer paper P is charged to a positive polarity by a paper suction roller 52 disposed near the end of the transfer belt 3 on the paper feed unit side, and is thereby electrostatically attracted to the transfer belt 3 for each transfer. It is conveyed to the part. When the transferred transfer paper P passes through each transfer portion in turn, the transfer brushes 57Y, 57M, 57C, and 57K transfer the Y, M, C, and K colors on the photoreceptors 4Y, 4M, 4C, and 4K. The toner images are sequentially superimposed and transferred. As a result, a four-color superimposed full-color toner image is formed on the transfer paper P. The transfer paper P on which the full-color toner image is formed is melt-fixed by applying heat and pressure by the fixing device 9. The transfer paper P after fixing passes through the discharge path corresponding to the designated mode and is reversely discharged to the paper discharge tray 12, or goes straight from the fixing device 9 and passes through the reversing unit 8 and is discharged straight. To do. Alternatively, when the double-sided image forming mode is selected, the sheet is fed back to the reversing conveyance path 54 in the reversing unit 8 and then switched back and conveyed to the double-sided unit 7. Then, the sheet is fed again from the image forming unit where each photoconductor unit 2 is provided, and is discharged after an image is formed on the back surface. Thereafter, when two or more image formations are instructed, the above-described image forming process is repeated.

  Next, the operation when the printer 100 forms a black and white image will be described. When the printer 100 receives black and white image data, the driven roller 53 supporting the transfer belt moves downward while facing the paper suction roller 52. As a result, the transfer belt 3 is separated from the yellow photoconductor 4Y, the magenta photoconductor 4M, and the cyan photoconductor 4. The black photoconductor 4K rotates clockwise in FIG. 1, and the surface of the black photoconductor 4K is uniformly charged by the charging roller 20. The photoreceptor 4K of the photoreceptor unit 2K is irradiated with laser light corresponding to the black image, and an electrostatic latent image is formed. When the electrostatic latent image reaches a developing area facing the developing device 5K, the electrostatic latent image is developed with black toner to form a toner image on the photoreceptor 4K. At this time, the image forming units (photosensitive unit 2K) of three colors other than black are stopped, and unnecessary wear is prevented.

On the other hand, the transfer paper P is separated from the paper feed cassette 13 or 14 by the separation paper feed roller 55 or 56 and fed to a pair of registration rollers 51 provided immediately before the transfer belt 3. . The registration roller pair 51 feeds the transfer paper P onto the transfer belt 3 at the timing when the leading edge coincides with the toner image formed on the black photoconductor 4K. The transferred transfer paper P is charged by a paper suction roller 52 disposed in the vicinity of the end of the transfer belt 3 on the paper feed unit side, and is electrostatically attracted to the surface of the transfer belt 3 by this charging. Since the transfer paper P is conveyed while being attracted to the transfer belt 3, even when the transfer belt 3 is separated from the yellow, magenta, and cyan photoconductors 4, it faces the black photoconductor 4K. And a black toner image is transferred. The transfer paper P on which the black toner image is formed is fixed by the fixing device 9 as in the case of the full-color image, and processed through a paper discharge path corresponding to the designated mode. Thereafter, when two or more image formations are instructed, the above-described image forming process is repeated.
In order to stably convey and transfer the transfer paper P, the transfer belt 3 needs to be made of a material having at least a surface layer having a high resistance. As a material of the transfer belt 3, a resin material such as polyvinylidene fluoride, polyimide, polycarbonate, polyethylene terephthalate, etc. can be molded into a seamless belt and used. These materials can be used as they are, or the resistance can be adjusted with a conductive material such as carbon black. Further, using these resins as a base layer, a surface layer may be formed by a method such as spraying or dipping to form a laminated structure.

Next, the photoreceptor units 2Y, 2M, 2C, and 2K will be described.
As shown in FIG. 2, the photoconductor unit 2 includes a photoconductor 4 on which an electrostatic latent image is formed, a charging roller 20 that uniformly charges the surface of the photoconductor 4, and a cleaning device 17 that cleans the surface of the photoconductor 4. With.
As shown in FIG. 2, a charging cleaning roller 49 for cleaning the roller surface is in contact with the charging roller 20.

  The cleaning device 17 includes a brush roller 21 that contacts the surface of the photosensitive member 4 and a cleaning blade 47, and includes a flicker device 19 that blows off toner adhering to the brush roller 21. Furthermore, a toner transport auger 48 that collects and transports the toner bounced off by the flicker member, a solid lubricant 16 disposed so as to contact the brush roller 21, and the like are provided. The solid lubricant 16 is pressed against the brush roller 21 by a solid lubricant pressure spring 60. The cleaning blade 47 is attached to the frame of the photoconductor unit 2 via the blade holder 61, and the tip thereof abuts on the surface of the photoconductor 4. The toner that has been scraped off by the cleaning blade 47 and accumulated in the portion E in FIG. 2 upstream of the surface moving direction of the photosensitive member 4 with respect to the blade contacting portion that is the contacting portion between the cleaning blade 47 and the photosensitive member 4. The brush roller 21 is rotated and carried. Then, the toner attached to the brush roller 21 is blown off by the flicker device 19 and moved to the toner conveying auger 48 side. The waste toner collected by rotating the toner transport auger 48 is transported to the waste toner storage unit 18 shown in FIG.

In this embodiment, the diameter of the photosensitive member 4 is φ30 [mm], and in the full color mode, each photosensitive member 4 is 162 [mm / sec] in the direction of arrow C in FIG. In this case, it rotates at 222 [mm / sec].
Further, the brush roller 21 is disposed so as to face the photosensitive member 4, is scraped off by the cleaning blade 47, discharges the toner accumulated in the portion E to the toner conveying auger 48, and removes the solid lubricant 16 to be photosensitive. Has the function of applying to the body 4.

Next, a cleaning embodiment according to the present invention will be described.
Examples of the cleaning target that moves on the surface include a conveyance member that conveys transfer paper to a transfer position and a toner image carrier, and examples of the toner image carrier include a photosensitive member that is a latent image carrier and an intermediate transfer member that is an intermediate transfer member. There is a transfer belt.
In this embodiment, cleaning of a photosensitive drum (simply referred to as a photosensitive member 4) in a state where toner after primary transfer remains as residual toner in a printer 100 as an image forming apparatus will be described.

FIG. 3 is an explanatory diagram of the cleaning blade 47 used in the printer 100.
As shown in FIG. 3, the cleaning blade 47 has an obtuse angle at the tip of the tip that is in contact with the photoreceptor 4. Then, as shown in FIG. 2, the ridge line formed by the two surfaces forming the obtuse angle is brought into contact with the photoconductor 4 in the counter direction. The tip angle θ1 of the cleaning blade 47 is 120 [°]. By making the tip angle an obtuse angle, the reciprocating motion (stick-slip motion) of the blade tip caused by the rotation of the photosensitive member 4 is suppressed, so that blade wear is also suppressed.
The tip angle θ1 is preferably 95 [°] to 135 [°]. If the angle is less than 95 [°], the effect of the obtuse angle shape is diminished, and the amount of blade wear may increase due to stick-slip motion. If it is 135 ° or more, when the cleaning blade 47 is pressurized, it will hit the photoconductor 4, or the contact area between the cleaning blade 47 and the photoconductor 4 will increase and the surface pressure will decrease. As a result, the cleaning ability decreases. In the cleaning blade 47 of this embodiment, the blade thickness t1 is 2 [mm] and the free length t2 is 7.3 [mm], but the shape of the blade is not limited to this.

As described above, the cleaning blade 47 having an obtuse tip angle is less likely to deform the ridge line portion when the photoreceptor 4 is rotated than the cleaning blade having a right tip angle. For this reason, the stick-slip movement is unlikely to occur, so the blade wear is small. However, when the cleaning blade 47 having an obtuse tip shape is used, foreign matters such as paper dust are likely to be caught between the cleaning blade 47 and the photosensitive member 4, and this causes a disadvantage that cleaning failure is likely to occur. all right.
The following reasons are presumed. The obtuse-angle-shaped cleaning blade is less deformed near the tip than the tip having a right-angle tip. If the tip is greatly deformed, the hardness is increased in a pseudo manner and the surface is difficult to deform, and it is difficult to take in foreign matters such as paper dust. On the other hand, when the deformation of the tip is small, a relatively slight deformation of the surface is allowed, and foreign matters such as paper dust are easily caught. In addition, the obtuse-shaped cleaning blade has less stick-slip motion at the tip than a right-angled cleaning blade, so that it is difficult to blow off foreign matter such as paper dust.
The state in which the foreign matter is sandwiched is a blade contact portion that should come into contact with the photosensitive member 4 and the cleaning blade 47. There is a foreign matter between the cleaning blade 47 and the photosensitive member 4, and the cleaning blade 47 and the photosensitive member. 4 is in a state where contact with 4 is prevented.
Therefore, the printer 100 includes a foreign matter removing unit that removes foreign matter caught in the blade contact portion.

Here, the foreign matter removing means of this embodiment will be described.
FIG. 4 is a block diagram illustrating the foreign matter removing means of the present embodiment.
As shown in FIG. 4, the foreign matter removing means of the printer 100 includes a control unit 200, a writing unit 6, a developing device 5, a photoreceptor driving device 40, a brush roller driving device 210, a transfer bias power source 50, and the like.

The control unit 200 has a function as a toner input control unit that performs control to attach non-image toner that does not contribute to image formation to the surface of the photoreceptor 4 during non-image formation and to input non-image toner to the blade contact portion. Prepare.
Specifically, as non-image formation, non-image toner is attached on the photosensitive member 4 at least one of the timing between successive image forming operations and the timing after the image forming operation. Thus, the writing unit 6 and the developing device 5 are controlled. In addition, the control unit 200 transfers the toner on the photosensitive member 4 so that the toner on the photosensitive member 4 does not move to the transfer belt 3 side at the timing when the region where the non-image toner adheres on the surface of the photosensitive member 4 passes the position facing the transfer belt 3. A transfer bias power source 50 that applies a transfer voltage to the brush 57 is controlled. Thereby, non-image toner is input to the blade contact portion.
The non-image toner is controlled so that a solid image or a halftone image toner image is formed on the photoconductor 4 so that the adhesion amount in the axial direction of the photoconductor 4 is substantially uniform. ] Is adhered on the photoreceptor 4.

As described above, when non-image toner is controlled to be input to the blade contact portion during non-image formation, the non-image toner is caught by the blade contact portion over time as compared with the case where control for inputting non-image toner is not performed. It was confirmed that the amount of foreign matter that would be in a state decreased.
The mechanism by which the foreign matter at the blade contact portion is removed by inputting non-image toner is not clear, but the following reasons are conceivable. That is, when non-image toner having a larger amount than the untransferred toner in a normal image forming apparatus is input to the blade contact portion, toner convection occurs in the blade contact portion and exists in the blade contact portion. Wash out foreign matter and make it easier to remove. The foreign matter washed out by the non-image toner is collected together with the toner in the portion E in FIG. 2 and removed from the photosensitive member 4 by the rotation of the brush roller 21. As described above, the foreign matter sandwiched between the blade contact portions can be washed out with the non-image toner and removed together with the toner, so that the amount of foreign matter sandwiched between the blade contact portions with time can be reduced. Presumed to be possible.
Further, even when foreign matter such as paper dust is present in the wedge-shaped space upstream of the surface of the photoreceptor 4 in the surface movement direction with respect to the blade contact portion, it can be washed out with non-image toner and removed together with the toner. It is possible to prevent foreign matter from being caught in the blade contact portion.

  Here, the brush roller 21 can input the non-image toner to the blade contact portion even when the brush roller 21 is driven to rotate as in the normal cleaning operation. This is because the amount of non-image toner is sufficiently large compared to the transfer residual toner that passes through the contact portion between the brush roller 21 and the photoconductor 4 during the normal cleaning operation, and therefore the non-image toner on the surface of the photoconductor 4 is carried. Even if the area to be passed passes through the contact portion with the brush roller 21, most of the non-image toner is input to the blade contact portion without being scraped off by the brush roller 21. In order to input the non-image toner to the blade contact portion more efficiently, at least while the region carrying the non-image toner on the surface of the photoconductor 4 passes through the contact portion with the brush roller 21, the brush roller 21 The brush roller driving device 210 may be controlled so as to stop the rotation.

The control unit 200 also has a function as a cleaning target surface movement control unit that performs control to move the surface of the photosensitive member 4 that is a cleaning target in a direction opposite to the surface movement direction during normal image formation.
Specifically, the control unit 200 controls the photoconductor driving device 40 at a predetermined timing during non-image formation, and the photoconductor 4 is normally cleaned by the cleaning device 17 during normal image formation. Is rotated in the direction opposite to the direction of rotation (direction of arrow C in FIG. 2).

As described above, when the photosensitive member 4 is controlled to rotate in the direction opposite to the rotation direction at the time of normal image formation during non-image formation, the blade abuts with time as compared with the case where the reverse rotation control is not performed. It was confirmed that the amount of foreign matter that was sandwiched between the parts decreased.
The following reason can be considered as the reason why the foreign matter at the blade contact portion is removed by rotating the photosensitive member 4 in the reverse direction. That is, at the blade contact portion, foreign matter such as paper dust is sandwiched under the influence of the force generated by the rotation of the photosensitive member 4 in the direction of arrow C in FIG. Therefore, by rotating the photoconductor 4 in the reverse direction, the direction of deformation of the blade tip is changed, or a force is applied in the reverse direction to when a foreign object is pinched, so that the blade contact portion is applied. It is presumed that the caught foreign matter can be removed.

FIG. 5 is a timing chart of control by the control unit 200 constituting the foreign matter removing unit.
For example, when the printer 100 receives continuous print image data of 20 designated sheets, the print is turned on (S1), and the above-described operation at the time of image formation is performed to execute printing (S2). Each time printing for one sheet is executed, the number of prints N and the number of continuous prints are counted (S3). The number N of prints is an indicator of whether the surface of the photoconductor 4 has moved by a predetermined amount of movement. In the printer 100, the amount of movement of the photoconductor 4 when five sheets are printed is set as a predetermined amount of movement. A = 5. After the number of prints N is counted, whether the number of prints is a predetermined value is compared (S4). If the value of N has not reached 5 (No in S4), the number of continuous prints becomes the specified number. Is determined (S7). If the number of continuous prints has not reached the designated number of 20 (No in S7), the next print is executed.
On the other hand, after the number of prints N is counted, if the value of the number of prints N has reached a predetermined value of 5 (Yes in S4), the control unit 200 performs continuous image forming operations as toner input control means. At the time of non-image formation at the timing during the image forming operation, non-image toner is input to the blade contact portion (S5). After the control for inputting the toner is performed, the value of the number of prints N is reset (S6), and it is determined whether the number of continuous prints is the designated number (S7). If the number of continuous prints has not reached the designated number of 20 (No in S7), the next print is executed again. On the other hand, when the number of continuous prints reaches the designated number of 20 sheets (Yes in S7), the control unit 200 functions as the cleaning target surface movement control unit and reverses the photosensitive member 4 during non-image formation after the completion of the image forming operation. The rotation is controlled (S8).

[Experiment 1]
Next, an experiment was conducted to compare the cleaning properties over time with a configuration in which the shape of the blade and the control for removing foreign substances are different.
As the shape of the blade, the obtuse angle cleaning blade 47 shown in FIG. 3 and the right-angled cleaning blade 47 shown in FIG. 6 were used.
As the control for removing foreign matter, the following foreign matter removal mode 1 and foreign matter removal mode 2 were adopted.
-Foreign matter removal mode 1
At the end of the continuous printing image forming operation, the photosensitive member 4 is reversely rotated. The amount of reversal is that the surface of the photoreceptor 4 moves about 4 [mm].
-Foreign matter removal mode 2
This is the same control as the control by the control unit 200 in the printer 100 described above. For every five printed sheets, 6 to 8 mg of non-image toner is adhered to the photoconductor 4, and the toner is input to the blade substantially uniformly in the axial direction of the photoconductor 4 which is the longitudinal direction. Then, when the continuous printing image forming operation is completed, the photosensitive member 4 is reversely rotated. The amount of reversal is that the surface of the photoreceptor 4 moves about 4 [mm].

And the running test was done on the following six conditions.
1) Right angle blade + no foreign matter removal mode 2) Obtuse angle blade + no foreign matter removal mode 3) Right angle blade + foreign matter removal mode 1
4) Obtuse-shaped blade + foreign matter removal mode 1
5) Right angle blade + foreign matter removal mode 2
6) Obtuse angled blade + foreign matter removal mode 2
In the running test, the photosensitive member linear velocity was 222 [mm / sec], repeated printing was performed with 5 continuous prints, and an abnormal image due to defective cleaning was checked. The right-angled blade is as shown in FIG. 5, and the angle of the tip contacting the photoreceptor 4 is a right-angle shape, and the angle is only different from that of the obtuse angle-shaped cleaning blade 47.
Table 1 shows the results of the cleaning rank with respect to the number of prints. “◯” indicates that there is no abnormal image, “Δ” indicates that a streak is occasionally generated due to poor cleaning, and “x” clearly indicates that a streak always occurs.

The evaluation results are (6), (4), (5), (3), (1), (2) in order, with condition (6 being the best evaluation and condition 2 being the worst evaluation). It can be seen that the cleaning performance can be maintained over a long period of time by adding the obtuse-shaped blade and the above-described foreign matter removal mode, which is to combine the foreign matter removal mode by suppressing the blade wear by making the tip angle of the cleaning blade obtuse. This indicates that the cleaning property can be maintained.

In the foreign matter removal mode 1, the control unit 200 has a function as a cleaning target surface movement control unit, and the effect of removing foreign matters such as paper dust accumulated on the blade contact portion by the reverse rotation of the photosensitive member 4 appears. .
In the foreign matter removal mode 2, the control unit 200 has a function as a cleaning target surface movement control unit and a function as a toner input control unit. Then, by inputting the toner to the blade contact portion at a predetermined interval, foreign matters such as paper dust existing at the blade contact portion where the photosensitive member 4 and the cleaning blade 47 contact are easily washed out and removed. Further, it is considered that the foreign matter can be removed by reversing the photosensitive member 4 thereafter.
In particular, in the foreign matter removal mode 2, for every five printed sheets, control for inputting non-image toner to the blade contact portion and control for reversing the photoreceptor 4 are performed. For this reason, the photosensitive member 4 can be reversed every time the toner is input, and the foreign matter that has been easily removed by the input of the toner can be more reliably removed.
Therefore, as in Condition 6, the printer 100 including the obtuse-shaped cleaning blade 47 and the control unit 200 that performs the control as in the foreign matter removal mode 2 can maintain good cleaning properties over time.

  In both the foreign matter removal mode 1 and the foreign matter removal mode 2, the control for performing the reverse operation of the photoconductor 4 was executed. However, if there is a problem due to the reverse operation such as an increase in torque, the toner input alone is sufficient, and the effect is reduced. However, the paper dust removal effect is expected. In this case, the control unit 200 has a function as a toner input control unit.

  In the foreign substance removal mode 2, the timing for inputting the non-image toner is performed every five sheets, but it is preferable to change the timing according to the system to be used. This is because if it is frequently performed, toner may be wasted. The same applies to the amount of non-image toner applied once, and the amount of input per time does not necessarily have to be 6 to 8 [mg] as in the foreign matter removal mode 2. If the amount of non-image toner applied to the toner is too small, the effect is reduced, and if it is too much, the toner is consumed wastefully, so it is preferable to change it appropriately depending on the system. The amount of reverse rotation, which is the amount of reverse surface movement of the photoreceptor 4, should also be changed flexibly depending on the system and unit shape, such as the amount of movement so that the waste toner before the cleaning blade does not go out of the unit. It is.

  As shown in FIG. 2, the printer 100 is in contact with the surface of the photoconductor 4 upstream of the blade contact portion on the surface movement direction (in the direction of arrow C in FIG. 2) of the photoconductor 4 during normal image formation. A brush roller 21 as a cleaning brush is provided. The provision of the brush roller 21 makes it difficult for foreign matters such as paper dust to move to the contact portion (blade contact portion) between the cleaning blade 47 and the photosensitive member 4. Further, the toner and foreign matter can be more efficiently discharged from the portion E in FIG. 2, which is a region upstream of the surface of the photosensitive member 4 in the surface movement direction with respect to the blade contact portion.

In the printer 100, the removal of foreign matters such as paper dust existing at the contact portion between the photosensitive member 4 and the cleaning blade 47 has been described. However, a unit in which a toner image carrier such as an intermediate transfer member and a cleaning blade are present as a member to be cleaned. If so, the same can be applied. Further, the member to be cleaned is not limited to the toner image carrier, but can also be applied to a sheet transfer / conveying member (transfer belt 3 in FIG. 1) that conveys the transfer sheet P as a recording member to the transfer unit. When a foreign matter removal unit similar to the foreign matter removal unit of the embodiment is applied to the sheet transfer conveyance member, the amount of non-image toner attached is set to be smaller than that in the case of the toner image carrier. When the toner is attached to the intermediate transfer member or the paper transfer / conveying member, it can be realized by transferring the non-image toner attached on the photosensitive member.
It should be noted that the unit in which the object to be cleaned is in contact with the paper is more likely to have an effect due to the provision of the foreign matter removing means.

Next, the charging unit of the printer 100 will be described.
The charging roller 20 is used to charge the surface of the photoconductor 4 so as to face the photoconductor 4. The charging roller 20 is in pressure contact with the surface of the photoconductor 4 via the gap management member 20 a, and the charging roller 20 opens a minute gap G (gap) from the surface of the photoconductor 4, and the photoconductor 4 is in contact with the photoconductor 4. Located in a non-contact state. A metal such as stainless steel is used for the core of the charging roller 20. If the mandrel is too thin, the influence of deflection when the charging member is cut or when the photosensitive member 4 is pressed cannot be ignored, and the required gap accuracy is difficult to obtain. Further, when the core bar is too thick, there is a problem that the charging roller 20 becomes large and the mass becomes heavy. Therefore, the diameter of the core bar is preferably about 6 to 10 [mm].

The charging roller 20 is preferably made of a material having a volume resistance of 10 ⁴ to 10 ⁹ [Ω · cm]. If the resistance is too low, charging bias leaks easily when the photoreceptor 4 has a defect such as a pinhole. If the resistance is too high, the discharge is not sufficiently generated and a uniform charging potential cannot be obtained.
The charging roller 20 is connected from a power source (not shown), and a predetermined voltage is applied. The voltage may be only a DC voltage, but is preferably a voltage obtained by superimposing an AC voltage on a DC voltage (DC voltage). By applying an AC voltage, the surface of the photoreceptor 4 can be more uniformly charged.
The charging roller 20 is soiled over time by foreign matters such as toner, external additives, and paper dust that have passed through the blade contact portion that is the contact portion between the cleaning blade 47 and the photosensitive member 4. Therefore, a charging cleaning roller 49 is disposed above the charging roller 20 as a member for cleaning the charging roller 20. The electrifying cleaning roller 49 is formed by bonding a roller made of an insulating sponge material called melamine foam to a core metal having a diameter of 5 [mm]. The charging cleaning roller 49 is in free contact with the charging roller 20 only by its own weight, and cleans the surface of the charging roller 20 while rotating in the accompanying direction as the charging roller 20 rotates.

Next, the photoconductor 4 will be described in detail.
The photoreceptor 4 is formed by laminating an undercoat layer, a charge generation layer mainly composed of a charge generation material, and a charge transport layer mainly composed of a charge transport material on a conductive support.
As the conductive support, one having a volume resistance of 10 ⁴ [Ω · cm] or less, for example, a metal tube such as aluminum or stainless steel, or a metal such as nickel processed into an endless belt shape is used. .

  In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is applied using a solvent, the resin is a resin having high resistance to general organic solvents. Is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, alcohol-soluble resins such as copolymer nylon, and curable resins that form a three-dimensional network structure such as polyurethane, alkyd-melamine, and epoxy. Further, a fine powder of metal oxide such as titanium oxide, silica, or alumina may be added to the undercoat layer in order to prevent moire and reduce residual potential. This undercoat layer can be formed using an appropriate solvent and coating method. The thickness of the undercoat layer is suitably from 0 to 5 [μm].

  The charge generation layer is a layer mainly composed of a charge generation material, and representative examples include a monoazo pigment, a disazo pigment, a trisazo pigment, and a phthalocyanine pigment. These charge generation materials can be formed by dispersing together with a binder resin such as polycarbonate using a solvent such as tetrahydrofuran or cyclohexanone and applying a dispersion. Application is performed by dip coating, spray coating, or the like. The thickness of the charge generation layer is usually 0.01 to 5 [μm].

  The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent such as tetrahydrofuran, toluene, dichloroethane, and applying and drying the solution. Among charge transport materials, low molecular charge transport materials include electron transport materials and hole transport materials. Examples of the electron transport material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 1, Examples include electron-accepting substances such as 3,7-trinitrodibenzothiophene-5,5-dioxide. Examples of hole transport materials include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, thiophene derivatives, etc. These electron donating substances are listed. The binder resin used in the charge transport layer together with the charge transport material is thermoplastic such as polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyester, polyarylate, polycarbonate, acrylic, epoxy, melamine, phenol, etc. Or a thermosetting resin is mentioned. The thickness of the charge transport layer may be appropriately selected in the range of 5 to 30 [μm] according to desired photoreceptor characteristics.

  Further, a protective layer can be formed on the surface of the photoreceptor for the purpose of protecting the photosensitive layer and improving durability. As a constitution of the protective layer, mechanical durability can be improved by dispersing a filler in a binder resin. The amount of the filler added to the protective layer is 10 to 70 parts by weight, preferably 20 to 50 parts by weight with respect to 100 parts by weight of the binder resin. When the amount of the filler is less than 10 parts by weight, the wear is large and the durability is inferior. As the filler added to the protective layer, fine powders of metal oxides such as titanium oxide, silica, and alumina can be used. When the particle size of the filler is too large, the exposure light is scattered by the protective layer, so that the resolution is lowered and the image quality is inferior. Moreover, when the particle size of a filler is too small, it is inferior to abrasion resistance. Therefore, the particle size of the filler added to the protective layer is suitably 0.1 to 0.8 [μm]. The protective layer can be formed by dispersing filler and binder resin using a suitable solvent and applying the dispersion by spray coating. The binder resin used for the protective layer, the solvent can be the same material as the charge transport layer, and as the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyester, polyarylate, There are thermoplastic or thermosetting resins such as polycarbonate, acrylic, epoxy, melamine, and phenol, and tetrahydrofuran, toluene, dichloroethane, and the like can be used as the solvent. The thickness of the protective layer is preferably 3 to 10 [μm] in order to improve the durability and not impair the electrostatic characteristics of the photosensitive layer. Furthermore, a charge transport material, an antioxidant, or the like can be added to the protective layer.

  In the printer 100 of the present embodiment, as described above, at least the photosensitive member 4 and the cleaning device 17 are integrally supported, and the photosensitive member unit 2 as a process cartridge is formed so as to be detachable by being retracted from the printer 100 main body. Is provided. In addition to this, the photosensitive unit 2 that is a process cartridge may include a developing device 5 as a developing unit. By such a photoreceptor unit 2, even in an image forming process in which development is performed using toner having a high circularity and a small particle diameter, image quality is deteriorated by preventing abnormal images due to poor cleaning. Therefore, the process cartridge can be reduced in number, and the process cartridge can be improved in service life and user maintenance.

Next, the toner suitably used for the printer 100 of the present embodiment will be described. The toner used in the printer 100 preferably has an average circularity of 0.93 to 1.00. Here, as the circularity, a 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.
Circularity a = L0 / L (1)
(L0 indicates the perimeter of a circle having the same projected area as the particle image, and L indicates the perimeter of the projected image of the particle.)
When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member 4 is small, so that the transferability is excellent.
On the other hand, toner with a high degree of circularity enters the gap between the photosensitive member 4 and the cleaning blade 47 in the blade type cleaning, and is easily slipped through. However, in the printer 100, since the tip angle of the cleaning blade 47 is an obtuse angle, poor cleaning can be suppressed even when toner with a high degree of circularity is used.

  In addition, the toner used in the printer 100 includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous solvent. It is a toner obtained by crosslinking and / or elongation reaction. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include 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 above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), 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 polyhydric alcohol (TO) 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 the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) 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 polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
The polycondensation reaction between polyhydric alcohol (PO) and polycarboxylic acid (PC) is heated to 150 to 280 [° C.] in the presence of a known esterification catalyst such as tetrabutoxy titanate or dibutyltin oxide, and reduced in pressure as necessary. The produced water is distilled off while obtaining a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation. The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) 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.); isocyanates; phenol derivatives, oximes, polyisocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyisocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 [wt%], preferably 1 to 30 [wt%], more preferably 2 to 20 [wt%]. If it is less than 0.5 [wt%], the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 [wt%], the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. 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.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  Examples of the trivalent or higher polyvalent amine compound (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 compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 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.

The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.
If [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  The urea-modified polyester 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.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyhydric carboxylic acid (PC) are produced in the presence of a known esterification catalyst such as tetrabutoxy titanate and dibutyltin oxide at 150 to 280 [° C.] and, if necessary, reduced pressure. Water is distilled off to obtain a polyester having a hydroxyl group. Next, at 40 to 140 [° C.], this is reacted with polyvalent isocyanate (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. Further, this (A) is reacted with amines (B) at 0 to 140 [° C.] to obtain a urea-modified polyester.

  When reacting polyvalent isocyanate (PIC) and reacting (A) and (B), a solvent may 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 isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and 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 or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the printer 100 which is a full-color image forming apparatus are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 [° C.], preferably 45 to 60 [° C.]. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15 [wt%], preferably 3 to 10 [wt%] based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is 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 charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 [° C.] works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. Effective against high temperature offset without applying a release agent such as oil to the fixing roller. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are 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 × 10 ⁻³ to 2 [μm], particularly preferably 5 × 10 ^{−3 to} 0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [m < ² > / g]. The use ratio of the inorganic fine particles is preferably 0.01 to 5 [wt%] of the toner, and particularly preferably 0.01 to 2.0 [wt%].
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, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination.

In particular, when stirring and mixing are performed using an average particle diameter of both fine particles of 5 × 10 ⁻² [μm] or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even with stirring and mixing in the developing device to obtain the charge level, the fluidity-imparting agent is not detached from the toner, and good image quality that does not cause firefly and the like can be obtained, and the residual toner is further reduced. Is planned.
Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large.
However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 [wt%], the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained. Stable image quality can be obtained even when copying is repeated.

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 [° C.] from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid 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 material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2000 parts by weight, it is not economical.

  Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.

  As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
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 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage which exists on the surface of a toner base particle becomes the range of 10-90 [%]. For example, polymethyl methacrylate fine particles 1 [μm] and 3 [μm], polystyrene fine particles 0.5 [μm] and 2 [μm], poly (styrene-acrylonitrile) fine particles 1 [μm], trade name is PB- 200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) and the like.
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, 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 acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, 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 compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  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. Among these, in order to make the particle size of the dispersion 2 to 20 [μm], a high-speed shearing method is preferable. When a high-speed shearing disperser is used, the number of rotations 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.].

(3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 [minutes] to 40 [hours], preferably 2 to 24 [hours]. It is. 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.

(4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

(5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

As described above, according to the present embodiment, the printer 100 that is an image forming apparatus includes the photosensitive member 4 that is a surface to be cleaned and the cleaning blade 47 in contact with the surface of the photosensitive member 4 and the surface of the photosensitive member 4. And a cleaning device 17 for cleaning. Further, the cleaning blade 47 provided in the cleaning device 17 has an obtuse angle at the tip angle formed by the two surfaces forming the ridge line of the cleaning blade 47 in contact with the photoreceptor 4. The control unit 200 serves as a foreign matter removing unit that removes foreign matter sandwiched between blade contact portions where the photosensitive member 4 and the cleaning blade 47 contact. The control unit 200 controls each member so as to remove the foreign matter sandwiched between the blade contact portions, whereby the foreign matter sandwiched between the blade contact portions can be removed. For this reason, it is possible to prevent an increase in the amount of foreign matter sandwiched between the blade contact portions over time by removing the foreign matter sandwiched between the blade contact portions. As a result, it is possible to prevent the occurrence of defective cleaning over time due to foreign matters such as paper dust being caught in the blade contact portion.
Further, the control unit 200 as a foreign matter removing unit of the printer 100 attaches non-image toner that does not contribute to image formation during non-image formation to the surface of the photoreceptor 4 and inputs the non-image toner to the blade contact portion. It has a function as toner input control means for performing control. By controlling the non-image toner to be input to the blade contact portion, the amount of foreign matter that becomes caught in the blade contact portion over time is reduced compared to the control that does not input non-image toner. Confirmed to do. As a result, it is possible to prevent the occurrence of defective cleaning over time due to foreign matters such as paper dust being caught in the blade contact portion.
The control unit 200 serving as a foreign matter removing unit of the printer 100 is a non-image toner when the surface of the photosensitive member 4 is moved by a moving amount corresponding to five prints as a predetermined moving amount. Is controlled to adhere to the surface of the photosensitive member 4. Thus, toner can be periodically input to the blade contact portion, and the occurrence of poor cleaning over time due to foreign matter such as paper dust being caught in the blade contact portion can be prevented.
Further, the control unit 200 as the foreign matter removing unit of the printer 100 moves the surface of the photosensitive member 4 in the direction opposite to the surface moving direction during normal image formation after the non-image toner is input to the blade contact portion. A function as a cleaning target surface movement control means for performing control is provided. Specifically, for every five printed sheets, control for inputting non-image toner to the blade contact portion and control for reversing the photoreceptor 4 are performed. For this reason, the photosensitive member 4 can be reversed every time the toner is input, and the foreign matter that has been easily removed by the input of the toner can be more reliably removed. Therefore, it is possible to prevent occurrence of poor cleaning over time due to foreign matters such as paper dust being caught in the blade contact portion.
Further, the control unit 200 as the foreign matter removing unit of the printer 100 is in a direction opposite to the surface moving direction of the photosensitive member 4 during normal image formation even when there is no non-image toner input as in the foreign matter removing mode 1. It may be provided with a function as an object to be cleaned surface movement control means for controlling the movement of the surface. When the non-image toner is not input and the photosensitive member 4 is controlled to be reversely rotated during non-image formation, the blade abutment is performed in a running experiment under the same conditions as compared to a case where such control is not performed. It was confirmed that the amount of foreign matter sandwiched between the parts decreased. For this reason, it is possible to remove foreign matter caught in the blade contact portion by rotating the photosensitive member 4 in the reverse direction, and the occurrence of poor cleaning over time due to foreign matter such as paper dust getting caught in the blade contact portion. Can be suppressed. Even if foreign matter such as paper dust exists in the wedge-shaped space on the upstream side in the surface movement direction of the photoreceptor 4 with respect to the blade contact portion, the foreign matter is moved upstream in the surface movement direction by reverse rotation. Therefore, it is possible to prevent foreign matter from being caught in the blade contact portion.
Further, the printer 100 serves as a cleaning brush that comes into contact with the surface of the photoconductor 4 on the upstream side in the surface movement direction (direction of arrow C in FIG. 2) during normal image formation of the photoconductor 4 with respect to the blade contact portion. A brush roller 21 is provided. The provision of the brush roller 21 makes it difficult for foreign matters such as paper dust to move to the contact portion (blade contact portion) between the cleaning blade 47 and the photosensitive member 4. Further, the toner and foreign matter can be more efficiently discharged from the portion E in FIG. 2, which is a region upstream of the surface of the photosensitive member 4 in the surface movement direction with respect to the blade contact portion.
In the printer 100, the member to be cleaned from which the foreign matter at the blade contact portion is removed by the foreign matter removing means is the photosensitive member 4 as a latent image carrier among the toner image carriers. A contact with the obtuse angle-shaped cleaning blade 47 on the photosensitive member 4 can achieve a good cleaning property for the residual toner, and a good cleaning property can be maintained by removing foreign matter from the blade contact portion. can do.
Further, the toner used in the printer 100 is a toner having a high circularity with a circularity of 0.93 or more. When the average circularity is 0.93 or more, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small, so that the transferability is excellent and a high-quality image can be obtained. . In addition, there is a problem that toner having a large average circularity is easily slipped off by blade-type cleaning. However, by using an obtuse angle-shaped cleaning blade 47, good cleaning performance is achieved for toner having a high circularity. It is possible to maintain a good cleaning property by removing the foreign matter from the blade contact portion.
Further, the toner used for image formation of the printer 100 is a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant and a release agent in an aqueous medium in the presence of resin particles. A toner obtained by performing at least one of a crosslinking and elongation reaction. Since the toner produced by such a polymerization method has the same charge-to-charge mass ratio for each toner particle, the transfer efficiency can be increased. Therefore, the amount of toner input to the blade contact portion as the transfer residual toner is small. For this reason, the cleaning property is improved.
The printer 100 includes a photosensitive unit 2 that is a process cartridge as a unit device that integrally supports at least the photosensitive member 4 and the cleaning device 17 that are to be cleaned, and is detachable from the printer 100 main body. . By forming the process cartridge, it is possible to improve convenience when the photosensitive member 4 and the cleaning device 17 are exchanged, and the user can easily exchange the photosensitive member 4 and the cleaning device 17 as a unit. Can be replaced.

1 is a schematic configuration diagram of a printer according to an embodiment. FIG. 2 is a schematic configuration diagram showing an internal configuration of a photoreceptor unit. Explanatory drawing of the cleaning blade used by this embodiment. The block diagram explaining the foreign material removal means of this embodiment. The timing chart of control by the control part which comprises a foreign material removal means. Explanatory drawing of the right-angle-shaped cleaning blade used in Experiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Photoconductor unit 3 Transfer belt 4 Photoconductor 5 Developing apparatus 6 Writing unit 7 Duplex unit 8 Reversing unit 9 Fixing apparatus 10 Reverse conveyance path 11 Paper discharge roller pair 12 Paper discharge tray 13 Paper feed cassette 15 Manual feed tray 16 Solid lubricant 17 Cleaning device 18 Waste toner storage unit 19 Flicker device 20 Charging roller 20a Gap management member 21 Brush roller 40 Photoconductor driving device 46 Conveying roller pair 47 Cleaning blade 48 Toner conveying auger 49 Charging cleaning roller 50 Transfer bias power supply 51 Resist Roller pair 52 Paper adsorbing roller 53 Driven roller 54 Reverse conveying path 55 Separating paper feeding roller 57 Transfer brush 60 Solid lubricant pressure spring 61 Blade holder 100 Printer 200 Control unit 210 Brush roller Operated device P transfer paper

Claims (7)

A surface to be cleaned,
A cleaning device for cleaning the surface of the object to be cleaned by bringing a cleaning blade into contact with the surface of the object to be cleaned;
In the image forming apparatus in which the tip angle formed by the two surfaces forming the ridge line of the cleaning blade that contacts the object to be cleaned is an obtuse angle shape,
It has a foreign substance removing means for removing foreign matter and該被cleaning element and the cleaning blade is sandwiched abutting blade contact portion,
The foreign matter removing means attaches non-image toner that does not contribute to image formation during non-image formation to the surface of the object to be cleaned, and controls to input the non-image toner to the blade contact portion. When,
To-be-cleaned object surface movement control means for controlling the surface of the object to be cleaned to move in the direction opposite to the surface moving direction during normal image formation after the non-image toner is input to the blade contact portion. An image forming apparatus comprising the image forming apparatus. The image forming apparatus according to claim 1 .
The image forming apparatus according to claim 1, wherein the toner input control means causes the non-image toner to adhere to the surface of the object to be cleaned when the surface of the object to be cleaned moves by a predetermined movement amount . The image forming apparatus 請 Motomeko 1 or 2,
An image forming apparatus, comprising: a cleaning brush that contacts the surface of the object to be cleaned on the upstream side in the surface movement direction of the object to be cleaned with respect to the blade contact part. The image forming apparatus according to claim 1, 2 or 3,
An image forming apparatus, wherein the member to be cleaned is a toner image carrier. Claims 1, 3 or in the image forming apparatus 4,
An image forming apparatus, wherein the toner used for image formation has a circularity of 0.93 or more. Claims 1,2,3, it was 4 or the image forming apparatus 7,
The toner used for image formation is a composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent, which is subjected to crosslinking and extension reaction in an aqueous medium in the presence of resin particles. An image forming apparatus comprising a toner obtained by performing at least one. Claim 1, 2, 3, 4, 5 or in the image forming apparatus 6,
An image forming apparatus comprising: a unit device that integrally supports at least the object to be cleaned and the cleaning device and is detachable from the main body of the image forming device.

Images