JP5212151B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic method, and more particularly to an image forming apparatus including a lubricant applying device that applies a lubricant to the surface of a photoreceptor.

  An image forming apparatus using an electrophotographic process includes a photoconductor as an image carrier, and charges the surface of the photoconductor by discharging, charges the surface of the photoconductor to form an electrostatic latent image, Toner is supplied to the electrostatic latent image to make it visible, and the formed visible image on the surface of the photoreceptor is transferred onto the surface of a recording material such as transfer paper, and then fixed and discharged.

  Since the untransferred toner remains on the surface of the photoconductor after the transfer of the visible image, the photoconductor surface is cleaned by a cleaning device so that they do not adversely affect the next image formation. Be prepared for the process. As a cleaning device, a device that removes deposits such as untransferred toner by bringing a cleaning blade made of an elastic material such as rubber into contact with the surface of the photoreceptor is generally known.

  In recent years, there has been an increasing demand for higher image quality, and in order to achieve particularly high-definition color image formation, toner particles are being made smaller and spherical. The dot reproducibility is improved by reducing the particle size of the toner, and the developability and transferability can be improved by making the toner spherical. Since it is very difficult to produce such a toner having a small particle size and spheroidization by a conventional kneading and pulverizing method, a polymerized toner produced by a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method or the like Is being adopted.

  However, when a toner having a spherical shape and a reduced particle size is used, there are some problems in cleaning on the photoreceptor after image formation. One of them is that it is difficult to clean a toner having a spherical shape and a small particle size by using a blade cleaning method generally used. The cleaning blade removes toner while rubbing the surface of the photoconductor, but the edge portion of the cleaning blade is deformed due to frictional resistance with the photoconductor, so that a minute space is generated between the photoconductor and the cleaning blade. The smaller the toner particle size, the easier it is to enter this space.

  Then, the closer to the spherical the shape of the toner that has entered, the smaller the rolling frictional force, so that the toner begins to roll in the space between the photosensitive member and the cleaning blade and passes through the cleaning blade. If a large amount of toner passes through the cleaning blade, the cleaning is poor, and an abnormal image such as a ground cover is generated.

  Also, as a second problem, the toner that has passed through the cleaning blade continues to remain on the surface of the photoconductor, and then the release agent or fluidizing agent contained in the toner causes the photoconductor to become the causative substance. The so-called filming, which is considered to be formed in a film form on the surface, can be mentioned. When filming is possible, an abnormal image such as a white spot on the solid portion of the image is generated.

  In order to improve the cleaning performance on the photoreceptor when using the above-described spherical or small-sized toner, a lubricant made of a fatty acid metal salt or the like is applied to the photoreceptor surface to form a thin film. For example, Patent Document 1 proposes a method for reducing the friction coefficient on the surface of the photoreceptor. It has been found that when the coefficient of friction on the surface of the photoconductor is lowered, the adhesion force acting between the photoconductor and the toner is reduced, so that blade cleaning is improved and filming is also suppressed.

  However, there is also a problem that occurs when the coefficient of friction on the surface of the photoreceptor becomes too low. This is because the adhesion between the photoconductor and the toner is reduced, so that in the development process, toner transfer from the developing roller to the electrostatic latent image formed on the photoconductor is not sufficient, resulting in image loss or low For example, it becomes a density image (see, for example, Patent Document 1 and Patent Document 2).

  For this reason, conventionally, many techniques have been tried in which the amount of lubricant applied is controlled while the surface of the photoconductor is scraped with a cleaning blade or the like, and the occurrence of abnormal images is suppressed by keeping the coefficient of friction of the photoconductor surface constant. .

  On the other hand, the demand for the paper thickness of the recording material is increasing year by year, and it is also necessary to form an image on a paper exceeding 200 kg, which is considerably thicker than plain paper. Fixing is the most constrained when forming images on thick paper, and it has already been possible to avoid thermal flaws due to paper thickness by adopting a thick paper mode, which is a low-speed mode during fixing, to secure thermal energy. It has been broken.

  In the type in which the image carrier and the intermediate transfer member are always in contact with each other, it is necessary to go back to the fixing unit, the intermediate transfer member, and the image carrier in order to prevent image blur due to a speed difference. In the thick paper mode, the time at the low speed at the time of fixing is much more than the time at the normal speed at the time of image formation, which is twice or more times.

  However, as a side effect when operating in the low speed mode as described above, as the image carrier is rotated at a low speed, the urethane rubber of the cleaning blade that is in contact with it is more likely to vibrate, and the lubricant is optimized at a normal speed. With the coating amount of 1, the surface friction coefficient of the image carrier may start to oscillate at about 100 Hz to 1000 Hz.

  In particular, when a high-density image (black solid image or the like) is output, the lubricant application amount may be drastically reduced. This is because during high-density image output, the amount of residual toner remaining on the photoconductor in the transfer process increases, and when the toner is cleaned with a blade or the like, the lubricant is removed together with the toner from the image carrier. is there. When the surface friction coefficient suddenly decreases in the low speed mode, the cleaning blade is more prone to vibrate.

  As a defect caused by the vibration of the cleaning blade, the vibration is applied to the image carrier and the intermediate transfer body, and the toner is transferred and visualized at the vibration cycle in the development process and the transfer process, so-called jitter image, Generates periodic abnormal images called banding images that occur in the main scanning direction. In addition, an abnormal sound having a vibration cycle called a so-called chatter sound is generated.

  As a means for avoiding such vibrations of the cleaning blade during low-speed rotation of the image carrier, the amount of lubricant applied during low-speed rotation is increased compared to during normal rotation, and the surface friction coefficient of the image carrier is reduced. Methods for preventing this are conceivable, and methods for controlling the amount of lubricant applied have been proposed in Patent Document 3 and Patent Document 4, both of which make the pressure of the lubricant applied to the application brush variable or the application brush. This is a method for controlling the number of rotations. In the method of controlling the pressure applied to the application brush of the lubricant, the pressure change means is required, and in the method of controlling the rotation speed of the application brush, the drive means for rotating the application brush is required, which increases the size of the apparatus and the number of parts. This leads to an increase in cost due to an increase in complexity, and is not preferable for recent demands for downsizing and cost reduction of devices.

  The present invention solves the above-mentioned problems in the conventional image forming apparatus, prevents the vibration of the cleaning blade even when operated at the linear speed of the image carrier on the low speed side, and prevents the occurrence of abnormal images and abnormal sounds. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

  According to the present invention, there is provided an image forming apparatus that visualizes a latent image formed on an image carrier as a toner image by a developing device, transfers the toner image onto a recording material, and fixes the image. In an image forming apparatus including a lubricant application device that applies a lubricant to the surface of a carrier, the linear velocity of the image carrier is provided so that the linear velocity of the image carrier can be changed. After completion of the transfer operation of the toner image to the recording material to be performed, control means for controlling the linear speed of the image carrier to be switched to the high-speed side linear speed for a predetermined time before starting the developing operation corresponding to the next recording material. It is solved by.

The predetermined time is preferably a time corresponding to at least one rotation of the image carrier.
The predetermined time is preferably a time corresponding to 10 to 20 rotations of the image carrier.
Further, when the image area ratio to be output is higher than a predetermined threshold, switching to the high-speed side linear velocity of the image carrier is performed, and when it is equal to or lower than the predetermined threshold, switching to the high-speed side linear velocity of the image carrier is performed. Preferably it is not implemented.

Further, it is preferable to switch the image carrier to the high-speed side linear speed according to the combination of the image area ratio to be output and the cumulative continuous output number.
Further, it is preferable to perform the operation of switching the photosensitive member linear velocity when the integration of the image area ratios in one job reaches a predetermined image area ratio.

Further, it is preferable to switch the image carrier to the high-speed side linear velocity according to the type of recording material to be used.
In addition, it is preferable to add the environmental condition to a condition that the switching to the high-speed side linear velocity of the image carrier is performed or not performed.

  Further, the predetermined time is changed according to any of the image area ratio, the combination of the image area ratio and the cumulative continuous output number, the integrated value of the image area ratio in the one job, the type of the recording material, and the environmental conditions. It is preferable.

The lubricant applied to the surface of the image carrier is preferably solidified zinc stearate.
The toner used has a weight average particle diameter of 3 to 8 μm and a ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) is in the range of 1.00 to 1.40. Preferably there is.

The shape factor SF-1 of the toner to be used is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180.
Further, the toner is preferably a toner obtained by externally adding fine particles having an average primary particle size of 50 to 500 nm on the surface of the toner base particles and a bulk density of 0.3 g / cm ³ or more.

The toner is preferably composed of at least a binder resin, a colorant, and a release agent, having a glass transition temperature of 45 to 65 ° C. and an outflow start temperature of 90 to 115 ° C.
The toner may be obtained by crosslinking and / or crosslinking a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an organic solvent is dispersed in an aqueous medium. A toner obtained by an elongation reaction is preferable.

According to the image forming apparatus of the present invention, it is possible to efficiently apply the lubricant to the surface of the image carrier in a short time even when outputting an image in the low speed mode.
Therefore, it is possible to prevent the occurrence of abnormal images and abnormal sounds even in the low speed mode, and to suppress the decrease in productivity as much as possible.

According to the second aspect of the present invention, the lubricant can be applied over at least the entire circumference of the image carrier.
According to the configuration of the third aspect, it is possible to reduce the friction coefficient on the surface of the image carrier and effectively prevent chatter noise.

According to the configurations of the fourth to ninth aspects, the lubricant can be efficiently applied when necessary, and the linear speed switching can be prevented from being performed unnecessarily.
With the configuration of the tenth aspect, the coefficient of friction on the surface of the image carrier can be effectively reduced.

  With the configurations of claims 11 to 15, high-quality image output can be performed, and even in that case, the lubricant can be efficiently applied to the surface of the image carrier.

1 is a cross-sectional configuration diagram illustrating an outline of a full-color multifunction peripheral as an example of an image forming apparatus according to the present invention. It is sectional drawing which shows the structure of a process cartridge. It is a perspective view which shows a part of process cartridge. It is an enlarged view which shows in detail the lubricant application device 20 part in FIG. It is a figure for demonstrating the measuring method of the friction coefficient of a photoreceptor. It is a graph which shows transition of the number of image formations and the number of photoreceptor surfaces when various images are continuously output. It is a figure which shows the result of having confirmed the presence or absence of generation | occurrence | production of the chatter sound in a certain environmental condition. It is a figure which shows the result of having confirmed the presence or absence of generation | occurrence | production of the chatter sound in different environmental conditions. 6 is a graph showing changes in the number of rotations of the photosensitive member and the surface friction coefficient when the photosensitive member is rotated without an image. FIG. 6 is a schematic diagram for explaining a shape factor of toner. It is a figure which shows the flow curve of the flow tester which measures the outflow start temperature of a toner.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram illustrating an outline of a full-color multifunction peripheral as an example of an image forming apparatus according to the present invention. The image forming apparatus 100 shown in FIG. 1 includes a document reading device 110 above the apparatus main body 120 and is configured as a copying apparatus. Machine.

  Inside the apparatus main body 120, four process cartridges 200 (Y, C, M, K), an endless intermediate transfer belt 62, a secondary transfer roller 65, and a toner bottle 59 for each color that supplies toner to the process cartridge. Etc. are arranged. An optical writing device 70 is disposed below a tandem image forming unit in which four process cartridges 200 are arranged in parallel. As will be described later, the process cartridge 200 includes an image carrier 10, a lubricant application device 20, a cleaning device 30, a charging device 40, and a developing device 50 (FIG. 2).

  The intermediate transfer belt 62 is positioned above the photoconductor 10 as each image carrier, and the lower running side of the intermediate transfer belt 62 is in contact with the circumferential surface of each photoconductor 10. The intermediate transfer belt 62 constitutes an example of a transfer material onto which toner images of different colors formed on the surface of each photoconductor 10 are transferred in a superimposed manner. A primary transfer roller 61 is disposed at a position facing the photoconductor 10 with the intermediate transfer belt 62 interposed therebetween.

  A fixing device 90 is provided above the secondary transfer portion where the secondary transfer roller 65 faces the opposing roller with the intermediate transfer belt 62 interposed therebetween. A paper feeding device 130 having a paper feeding cassette containing a recording medium made of transfer paper, for example, is disposed below the apparatus main body 120. The upper surface of the apparatus main body 120 is configured as a paper discharge unit 58.

FIG. 2 is a cross-sectional view showing the configuration of the process cartridge 200.
As shown in this figure, the process cartridge 200 includes a photoreceptor 10, a lubricant application device 20, a cleaning device 30, a charging device 40, and a developing device 50. The process cartridges 200 of the respective colors (Y, C, M, K) are substantially the same in configuration and operation except that the color of the handled toner is different.

  The lubricant application device 20 includes a solid lubricant 21, a lubricant holding member 24 that supports the solid lubricant 21, and a lubricant application brush roller that rotates in contact with both the solid lubricant 21 and the photoreceptor 10. 22 and a lubricant application blade 23.

  The lubricant-applying brush roller 22 is driven by a drive transmission means (not shown) and a gear disposed at the end thereof, and the drive force is transmitted from the gear disposed at the end of the photoreceptor 10 to rotate, and the powder scraped from the solid lubricant 21 A lubricant is applied to the surface of the photoreceptor 10. Further, the lubricant application blade 23 leveles the lubricant applied to the surface of the photoconductor 10 to make the thickness uniform.

The cleaning device 30 is provided with a cleaning blade 31 that comes into contact with the surface of the photoconductor 10 to clean and collect toner remaining on the surface of the photoconductor.
The charging device 40 is mainly composed of a charging roller 41 disposed so as to contact the photoreceptor 10 and a charging roller cleaner 42 rotating in contact with the charging roller 41. The charging roller 41 uniformly charges the surface of the photoreceptor 10, and the charging roller cleaner 42 cleans the surface of the charging roller 41.

  The developing device 50 includes a developing roller 51 that supplies toner as a developer to the surface of the photoreceptor 10 to visualize the electrostatic latent image, and a mixing roller that stirs the developer stored in the developer storage unit. 52, a supply roller 53 for supplying the developer mixed and stirred to the developing roller 51, and a doctor blade 54 as a layer thickness regulating member.

FIG. 3 is a perspective view showing a part of the process cartridge 200.
In this figure, this process cartridge 200 has a frame body 11 and side plates 12 respectively disposed at both ends of the frame body 11, and the photoreceptor 10, the solid lubricant 21, and the lubrication between the side plates 12. An agent application brush roller 22 is installed. The solid lubricant 21 is integrally supported by the holding member, and is urged toward the lubricant application brush roller 22 by a spring member of a pressing unit (not shown), and the surface thereof contacts the lubricant application brush roller 22. ing.

FIG. 4 is an enlarged view showing in detail the lubricant coating device 20 portion in FIG.
As shown in this figure, the lubricant application device 20 includes a solid lubricant 21 and a lubricant holding member 24 that supports the solid lubricant 21, and accommodates the solid lubricant 21 together with the lubricant holding member 24. A lubricant holder 25 is provided.

  A pair of cam-shaped blade members (hereinafter also referred to as cam members) 26 are provided between the lubricant holding member 24 and the bottom of the lubricant holder 25 at a predetermined interval. A spring member (not shown) made of, for example, a helical spring is installed between them. The spring member gradually raises the cam member 26 by a restoring force that acts to narrow the interval between the cam members 26, thereby pressing the bottom portion of the lubricant holder 25 and using the reaction force to lubricate the cam member 26. The solid lubricant 21 supported by the agent holding member 24 is configured to always contact the lubricant application brush roller 22 with a predetermined contact pressure.

A printing operation of the image forming apparatus configured as described above will be described.
First, the photosensitive member 10 of the process cartridge 200 is driven to rotate clockwise in FIG. 1, and the surface thereof is charged to a predetermined polarity by the charging roller 41 of the charging device 40 to which a charging voltage is applied. The charged photoreceptors 10 are irradiated with, for example, a laser beam emitted from the optical writing device 70 and subjected to light modulation, thereby forming an electrostatic latent image on the surface of each photoreceptor 10. Each electrostatic latent image is supplied with a developer of each color from the developing roller 51 of the developing device 50, and a toner image corresponding to each developer is formed to be visualized.

  Next, a transfer voltage is applied to the primary transfer roller 61 so that each toner image on the photoreceptor 10 is primarily transferred onto the rotating intermediate transfer belt 62 to form a color image as a composite image. The color image primarily transferred onto the intermediate transfer belt 62 is discharged from the paper feed cassette of the paper feeding unit 130 at a predetermined timing and fed between the intermediate transfer belt 62 and the secondary transfer roller 65. Secondary transfer to.

  The recording paper on which the color image is secondarily transferred is sent to the downstream fixing device 90, where the color image on the recording paper is fixed on the recording paper by the action of heat and pressure. Next, the recording paper on which the color image is fixed is discharged to a paper discharge unit 58 at the top of the image forming apparatus main body 120 by a pair of paper discharge rollers.

  On the other hand, untransferred toner adhering to the photoreceptor 10 after the toner image is transferred is collected and removed by the cleaning blade 31 of the cleaning device 30 shown in FIG. A lubricant is applied to the cleaned surface of the photoreceptor 10 by the lubricant application device 20. That is, as shown in FIG. 4, solid lubrication is performed by the lubricant application brush roller 22 that rotates in contact with both the solid lubricant 21 and the photoreceptor 10 slidably accommodated in the lubricant holder 25. The agent 21 is scraped off and applied to the surface of the photoreceptor 10 as a powdery lubricant.

Next, the surface friction coefficient of the photosensitive member during operation will be described.
Here, the friction coefficient of the photoreceptor 1 was measured by the Euler belt method as follows.
FIG. 5 is a diagram for explaining a method of measuring the friction coefficient of the photosensitive member. In this case, medium-quality high-quality paper as a belt is stretched around the drum circumference ¼ of the photosensitive member 1 so that the paper is in the longitudinal direction, and a load of, for example, 0.98 N (100 gr) is applied to one of the belts. Then, install a force gauge on the other side, pull the force gauge, and read the load at the time when the belt moves, and the friction coefficient μs = 2 / π × 1n (F / 0.98) (where μ is the coefficient of static friction) , F: measured value).

FIG. 6 shows the results of measuring the transition of the number of image formations (the number of continuous sheets to be passed) and the number of photoreceptor surfaces when various images are continuously output in the image forming apparatus having the above configuration.
A4 size plain paper was used as the recording paper, and the paper passing direction was the short direction. In addition, the process cartridge to be measured is unified with the M process cartridge in order to prevent variations in measurement values due to other disturbances such as adhesion of reverse transfer toner from the intermediate transfer belt to the photosensitive member. The images to be passed through the measurement are M single colors, and the image area ratios are 0%, 5%, 20%, 50%, and 100% with respect to the total area of the recording paper, so that the image distribution in the main scanning direction is uniform. I made it.

  Before the measurement, 50 images with an image area ratio of 0% were passed, so that the lubricant coating state on the surface of the photoreceptor was constant. From this state, each of the above-mentioned images was continuously passed, and the photoreceptor surface friction coefficient after passing was measured. As shown in the graph of FIG. 6, as the image area ratio is higher, the increase in the coefficient of friction of the photoreceptor surface with respect to the number of sheets to be passed becomes remarkable.

  Next, in the image forming apparatus having the above-described configuration, the cleaning blade when the surface friction coefficient of the photosensitive member is shaken at 23 ° C. 50% Rh, 10 ° C. 15% Rh environment, 160 mm / sec, 80 mm / sec. The results of confirming whether or not chatter noise is generated due to vibration are shown in the graphs of FIGS. As shown in each figure, it was found that chatter noise was generated when the surface friction coefficient of the photoconductor increased on the low linear velocity side, and that the photoconductor friction coefficient began to be generated in a low temperature and low humidity environment. .

The graph of FIG. 9 shows the results of measuring the number of rotations of the photoreceptor and the transition of the surface friction coefficient when the photoreceptor is rotated without an image with respect to the photoreceptor having an increased surface friction coefficient.
By rotating the photoconductor without toner consumption, the lubricant is not transferred to the intermediate transfer body together with the toner, so the surface friction coefficient of the photoconductor decreases as the number of rotations increases. Asymptotically about 1.0.

Based on these experimental results, in this embodiment, the photosensitive member linear velocity according to the paper type is set as follows.
In the present invention, the photosensitive member, the primary transfer roller, the intermediate transfer belt, and the secondary transfer roller are always operated at the same linear speed in order to prevent transfer blur. The fixing roller is set to a slightly slower linear speed than each of the rollers (rotating bodies).

  The above linear speed can be switched between the case where the recording paper is plain paper and the case where the recording paper is OHP, thick paper, and ultra-thick paper. In the latter case, 1/2 to 1/3 of the linear speed of the plain paper. Is set to be. This is because when the recording paper is OHP, thick paper, or ultra-thick paper, the linear speed of the recording paper needs to be lowered because the thickness of the paper is large and the fixing efficiency is lowered at the same linear speed as that of the plain paper.

  Of course, it is conceivable to change the linear velocity when the recording paper enters the fixing unit. However, in the layout of this embodiment, when a long recording paper such as A3 size paper is used, the leading edge of the recording paper is At the time of entering the fixing means, the rear end of the recording paper is still in the secondary transfer portion, and the change in the linear velocity during the secondary transfer causes image blurring, so that it is difficult to adopt.

  Specifically, when the recording paper is 55 kg to 90 kg paper, the “plain paper” mode is operated from the start of image formation to the secondary transfer at a linear speed of 160 mm / sec. The fixing roller operates at a slightly slower speed of 158 mm / sec.

  When the recording paper is 136 kg to 220 kg paper, the “thick paper” mode is set from an operation unit (not shown) to operate at a linear speed of 80 mm / sec. The fixing roller operates at a slightly slower speed of 78 mm / sec.

A specific operation process in the present embodiment will be described below.
When outputting in the “thick paper” mode, the image forming process described above is performed at a linear speed of 80 mm / sec, but after the trailing edge of the recording paper has passed through the secondary transfer nip, The transfer roller 65 temporarily stops and operates again at the “plain paper” mode linear speed of 160 mm / sec before starting the developing operation by the developing device. When the recording paper is discharged and the next recording paper image forming operation is started, the photosensitive member 10 to the secondary transfer roller 65 once again stop and operate again at the “thick paper” mode linear velocity of 80 mm / sec. . As a result, the lubricant can be efficiently applied to the surface of the photoreceptor in a short time even when outputting an image in the low speed mode. The switching of the linear velocity is controlled by a control unit (not shown) of the image forming apparatus.

  In order to apply the lubricant over the entire circumference of the photoconductor, the photoconductor rotation time on the high speed side is required to be at least one rotation. When a photoconductor having a diameter of 40 mm is used, 40 × π / 160 = 0.785 sec. As described above, as described with reference to FIG. 9, the photoreceptor surface friction coefficient decreases as the number of rotations increases. Therefore, an appropriate number of rotations is set.

  Further, as described with reference to FIG. 6, since the rising tendency of the photosensitive member surface friction coefficient differs depending on the image area to be output, a threshold value is provided depending on the output image to select whether or not to perform the linear speed switching operation. And For example, even if the image forming apparatus measured in FIG. 6 continues to output an image with an image area ratio of 20% or less, the photosensitive member surface friction coefficient is maintained at 1.3 or less, and the experimental results shown in FIG. It does not rise to the photoconductor surface friction coefficient where chatter noise such as Accordingly, the threshold value of the image area ratio is set to 20%, the linear speed switching operation is performed when the output image area ratio> 20%, and the linear speed switching operation is not performed when the output image area ratio ≦ 20%. Set.

  Further, since the surface friction coefficient of the photosensitive member increases with the number of output sheets, a table as shown in the following Table 1 is created from the result of FIG. 6, and whether or not the photosensitive member linear speed switching operation is performed is determined accordingly. It can also be controlled. That is, it is control for determining whether or not to perform the operation of switching the photosensitive member linear velocity based on the combination of the image area ratio and the cumulative continuous output number.

  Alternatively, when the integration of the image area ratio in one job in the low-speed mode (the integration of the image area ratio for each output recording sheet) reaches a predetermined image area ratio, the operation of switching the photosensitive member linear speed is performed. You may control to implement.

  In addition to this, the photosensitive member surface friction coefficient decreases with the number of rotations of the photosensitive member as described with reference to FIG. 9, and therefore the photosensitive member rotation number when switching to the high-speed side linear velocity may be set according to the image area ratio. . That is, the higher the image area ratio, the more the photosensitive member rotation speed at the higher side linear velocity may be increased. Similarly, the rotational speed of the photosensitive member when switching to the high-speed side linear speed may be set according to the combination of the image area ratio and the cumulative continuous output number. Similarly, the rotational speed of the photosensitive member when switching to the high-speed side linear speed may be set according to the integrated value of the image area ratio in one job.

  Further, as described with reference to FIGS. 7 and 8, the photosensitive member surface friction coefficient at which chatter noise is generated varies depending on the environmental conditions. Therefore, the environmental conditions may be added to the switching condition to the high-speed side linear velocity. In other words, the setting may be a combination of the environmental conditions and the type of recording paper. Further, the setting may be a combination of the environmental condition and the image area ratio. Further, the setting may be made according to the combination of the environmental condition, the image area ratio, and the cumulative continuous output number. Further, in those cases, the rotational speed of the photosensitive member when switching to the high side linear velocity may be set according to the environmental conditions. That is, the photosensitive member rotation speed at the higher side linear velocity may be increased as the low sound / humidity environment is achieved.

Finally, a toner that is preferably used in the present invention will be described.
In order to reproduce fine dots of 600 dpi or more, the toner preferably has a weight average particle diameter of 3 to 8 μm. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent.

  When the weight average particle diameter (D4) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. Further, if the weight average particle size (D4) exceeds 8 μm, it is difficult to suppress scattering of characters and lines. Moreover, it is preferable that ratio (D4 / D1) of a weight average particle diameter (D4) and a number average particle diameter (D1) exists in the range of 1.00-1.40. The closer (D4 / D1) is to 1.00, the sharper the particle size distribution.

  With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

Next, a method for measuring the particle size distribution of toner particles will be described.
As an apparatus for measuring the particle size distribution of toner particles by the Coulter Counter method, there are Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).

The measurement method is described below.
First, 0.1 to 5 mL of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 mL of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used.

Here, 2 to 20 mg of a measurement sample is further added.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the mass and number of toner particles or toner using a 100 μm aperture as an aperture. Calculate mass distribution and number distribution. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  The shape factor SF-1 of the toner is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. FIG. 10 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2.

The shape factor SF-1 indicates the ratio of the roundness of the toner shape, and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) 2 / AREA} × (100π / 4) Expression (1)
When the value of SF-1 is 100, the shape of the toner is a true sphere, and becomes irregular as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) 2 / AREA} × (100 / 4π) Expression (2)
When the SF-2 value is 100, the unevenness on the toner surface does not exist, and as the SF-2 value increases, the unevenness on the toner surface becomes more prominent.

  Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

  When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 or SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

The toner of the present invention is a toner obtained by externally adding fine particles having an average primary particle diameter of 50 to 500 nm and a bulk density of 0.3 g / cm ³ or more to the surface of the base particles.
By using fine particles having an average primary particle size of 50 to 500 nm and a bulk density of 0.3 mg / cm ³ or more as an external additive, a small particle size toner having good cleaning properties and particularly achieving high image quality. When used, improvement in developability and transferability is improved.

Hereinafter, the toner of the present invention will be described in detail.
In the toner of the present invention, fine particles (hereinafter, simply referred to as fine particles) having an average primary particle diameter of 50 to 500 nm and a bulk density of 0.3 mg / cm ³ or more are adhered to the toner particle surface. In addition, although silica etc. are often used for a normal fluid improvement agent, for example, the average primary particle diameter of this silica is 10-30 nm normally, and a bulk density is 0.1-0.2 mg / cm < ³ >.

In the present invention, since fine particles having appropriate characteristics are present on the surface of the toner, an appropriate gap is formed between the toner particles and the object.
Further, the fine particles have a very small contact area with the toner particles, the photoconductor, and the charge imparting member and are evenly contacted with each other, so that the effect of reducing the adhesive force is great and effective in improving the development / transfer efficiency.

  Furthermore, since it plays the role of a roller, it is difficult to be buried in toner particles even when cleaning under high stress such as high load and high speed between the cleaning blade and the photoconductor without wearing or damaging the photoconductor, Alternatively, even if it is buried a little, it can be detached and restored, so that stable characteristics can be obtained over a long period of time.

Further, the toner is moderately detached from the surface of the toner and accumulated at the tip of the cleaning blade, and the so-called dam effect has an effect of preventing a phenomenon that the toner passes from the blade.
Since these characteristics have an effect of reducing the share received by the toner particles, the filming effect of the toner itself due to the low rheological component contained in the toner is exhibited for high-speed fixing (low energy fixing).

  In addition, when fine particles having an average primary particle size in the range of 50 to 500 μm are used, the excellent cleaning performance can be fully utilized, and since the particle size is extremely small, the powder fluidity of the toner is improved. There is no reduction. Further, although the details are not clear, even if the surface-treated fine particles are externally added to the toner or the carrier is contaminated, the degree of developer deterioration is small.

  The average primary particle size (hereinafter referred to as the average particle size) of the fine particles is 50 to 500 nm, and particularly preferably 100 to 400 nm. If the thickness is less than 50 nm, the fine particles may be buried in the concave and convex portions on the toner surface to lower the role of the rollers.

On the other hand, when the particle size is larger than 500 μm, when the fine particles are located between the blade and the surface of the photosensitive member, the order is the same level as the contact area of the toner itself, and the toner particles to be cleaned pass, that is, defective cleaning occurs. It becomes easy. When the bulk density is less than 0.3 mg / cm ³ , although there is a contribution to the improvement of fluidity, the scattering property and adhesion of the toner and fine particles become high, so the effect as a toner and a roller, and the accumulation in the cleaning unit. As a result, the so-called dam effect that prevents toner cleaning failure is reduced.

  In the fine particles of the present invention, the inorganic compounds include SiO2, TiO2, Al2O3, MgO, CuO, ZnO, SnO2, CeO2, Fe2O3, BaO, CaO, K2O, Na2O, ZrO2, CaO.SiO2, K2O (TiO2) n, Al2O3. -2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, SrTiO3 etc. can be illustrated, Preferably, SiO2, TiO2, Al2O3 is mention | raise | lifted. In particular, these inorganic compounds may be hydrophobized with various coupling agents, hexamethyldisilazane, dimethyldichlorosilane, octyltrimethoxysilane, and the like.

  The organic compound fine particles may be thermoplastic resins or thermosetting resins, such as vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, Examples include urea resins, aniline resins, ionomer resins, and polycarbonate resins.

As the resin fine particles, two or more of the above resins may be used in combination.
Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.

  Specific examples of vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid. -Acrylate ester copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene- (meth) acrylic acid copolymer, and the like.

The bulk density of the fine particles was measured by the following method.
Using a 100 mL graduated cylinder, fine particles were gradually added to make 100 mL. At that time, no vibration was applied.

The bulk density was measured by the difference in mass before and after putting the fine particles of the graduated cylinder.
Bulk density (g / cm ³ ) = fine particle amount (g / 100 mL) ÷ 100
The fine particles of the present invention can be externally added and adhered to the toner surface by mechanically mixing and adhering the toner base particles and fine particles using various known mixing devices, or in the liquid phase. There is a method in which the base particles and the fine particles are uniformly dispersed with a surfactant or the like, and are dried after the adhesion treatment.

  Many toner characteristics related to toner fixing properties are known, and in particular, it is known that a ½ outflow temperature (softening point) is related. For the fixing device of the present invention, a ½ outflow temperature is known. (Softening point) No relationship was found in the fixability, and a good fixability was obtained by using a toner satisfying both characteristics of a glass transition temperature of 45 to 65 ° C. and an outflow start temperature of 90 to 115 ° C. It is done.

  When the glass transition temperature is lower than 45 ° C., offset may occur during fixing. Conversely, when the glass transition temperature is higher than 65 ° C., sufficient fixing property cannot be obtained, and the image is easily peeled off from the transfer paper. There is.

  If the outflow start temperature is lower than 90 ° C, offset may occur during fixing. Conversely, if it is higher than 115 ° C, sufficient fixability cannot be obtained, and the image tends to peel off from the transfer paper. There is.

A method for measuring Tg will be outlined.
As a device for measuring Tg, a TG- ^ DSC system TAS-100 manufactured by Rigaku Corporation was used.

First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace.
First, after heating from room temperature to 150 ° C. at a temperature rising rate of 10 ° C./min, the sample was allowed to stand at 150 ° C. for 10 min, the sample was cooled to room temperature and left for 10 min, and the temperature rising rate was again increased to 150 ° C. under a nitrogen atmosphere. DSC measurement was performed by heating at min.

Tg was calculated from the contact point between the tangent line of the endothermic curve near the Tg and the base line using the analysis system in the TAS-100 system.
The toner flow start temperature can be measured using a flow tester.
An example of a flow tester is an elevated flow tester CFT500D manufactured by Shimadzu Corporation.

The flow curve of this flow tester becomes the data shown in FIGS. 11A and 11B, from which each temperature can be read. In the figure, Tfb is the outflow start temperature, and the melting temperature in the 1/2 method is the T1 / 2 temperature.
(Measurement conditions) Load: 5 kg / cm ² , heating rate: 3.0 ° C./min, die diameter: 1.00 mm, die length: 10.0 mm

As the binder resin used in the toner of the present invention, those having the following composition can be used as long as the characteristics of the toner of the present invention are satisfied.
For example, styrene and its substituted homopolymers such as polyester, polystyrene, poly p-chlorostyrene, polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer , Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl acetate Copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester Examples thereof include styrene copolymers such as copolymers.

Moreover, the following resin can also be mixed and used.
Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or fat Examples thereof include cyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax.

Among these, a polyester resin is particularly preferable in order to obtain sufficient fixability.
Polyester resin is obtained by condensation polymerization of alcohol and carboxylic acid. The alcohol used is polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butane. Diols such as diol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyexethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. And a divalent alcohol simple substance obtained by substituting these with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, and other divalent alcohol simple substance.

  Examples of the carboxylic acid used to obtain the polyester resin include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, Adipic acid, sebacic acid, malonic acid, divalent organic acid monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, acid anhydrides thereof, lower alkyl esters and linolenic acid Dimers and other divalent organic acid monomers can be mentioned.

  In order to obtain a polyester resin to be used as a binder resin, it is also preferable to use not only a polymer with only the above bifunctional monomer but also a polymer containing a component with a trifunctional or higher polyfunctional monomer. It is.

  Examples of the polyhydric alcohol monomer having three or more valences as the polyfunctional monomer include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sarbitane, pentaesitol, dipenta. Esitol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol , Trimethylolethane, trimethylolpropane, 1.3.5-trihydroxymethylbenzene, and the like.

  Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2, 5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2 -Methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and the like.

The toner of the present invention may contain a release agent for the purpose of improving the releasability of the toner on the surface of the fixing belt at the time of fixing.
As the release agent, all known ones can be used, and in particular, defree fatty acid type carnauba wax, montan wax, oxidized rice wax, and ester wax can be used alone or in combination.

The carnauba wax is preferably a microcrystalline one, having an acid value of 5 or less and a particle size of 1 μm or less when dispersed in a toner binder.
The montan wax generally refers to a montan wax refined from minerals, and like a carnauba wax, it is microcrystalline and preferably has an acid value of 5 to 14.

The oxidized rice wax is obtained by air-oxidizing rice bran wax, and the acid value is preferably 10-30.
When the acid value of each wax is less than the respective range, the low temperature fixing temperature rises and the low temperature fixing becomes insufficient. On the contrary, when the acid value exceeds each range, the cold offset temperature rises and the low-temperature fixing becomes insufficient.

The added amount of the wax is 1 to 15 parts by mass, preferably 3 to 10 parts by mass with respect to 100 parts by mass of the binder resin.
If the amount is less than 1 part by mass, the releasing effect is thin and the desired effect is difficult to obtain.

Moreover, when it exceeds 15 mass parts, the problem that the spent to a carrier became remarkable occurred.
Further, for the purpose of imparting charge to the toner, a charge control agent can be contained. Any conventionally known charge control agent can be used.

  Examples of positive charge control agents include nigrosine, basic dyes, lake dyes of basic dyes, quaternary ammonium salt compounds, etc., and examples of negative charge control agents include metal salts of monoazo dyes, salicylic acid, naphthoic acid, dyes, and the like. Examples include carboxylic acid metal complexes and the like.

  The amount of the polarity control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is not limited uniquely. However, it is used in the range of 0.01 to 8 parts by mass, preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the binder resin.

If it is less than 0.01 part by mass, the effect is small with respect to fluctuations in the charge amount Q / M at the time of environmental change, and if it exceeds 8 parts by mass, the low-temperature fixability is inferior.
Further, as the metal-containing monoazo dye to be used, a chromium-containing monoazo dye, a cobalt-containing monoazo dye, and an iron-containing monoazo dye can be used alone or in combination.

By adding these, the rising of the charge amount Q / M in the developer (time until saturation) becomes more excellent.
The amount used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method as in the case of the polar control agent, and is uniquely limited. However, it is used in the range of 0.1 to 10 parts by mass, preferably 1 to 7 parts by mass with respect to 100 parts by mass of the binder resin. If the amount is less than 0.1 parts by mass, the effect is small, and if the amount exceeds 10 parts by mass, defects such as a decrease in the saturation level of the charge amount occur.

  In addition, it is particularly preferable to use a metal salt of a salicylic acid derivative for the color toner, but if necessary, a transparent or white substance that does not impair the color tone of the color toner is added to stabilize the chargeability of the toner. Can be granted.

Specifically, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds and the like are used, but are not limited thereto.
Furthermore, the toner of the present invention further contains a magnetic material and can be used as a magnetic toner.

  Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum, cobalt, copper, lead, magnesium, tin, and zinc of these metals. And alloys of metals such as antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.

  These ferromagnetic materials desirably have an average particle size of about 0.1 to 2 μm. The amount of the ferromagnetic material to be contained in the toner is about 20 to 200 parts by mass, particularly preferably 100 parts by mass of the resin component, with respect to 100 parts by mass of the resin component. It is 40-150 mass parts with respect to a part.

As the colorant, all known colorants can be used.
As the black colorant, for example, carbon black, aniline black, furnace black, lamp black and the like can be used.

Examples of cyan colorants include phthalocyanine blue, methylene blue, Victoria blue, methyl violet, aniline blue, and ultramarine blue.
As the magenta colorant, for example, rhodamine 6G lake, dimethylquinacridone, watching red, rose bengal, rhodamine B, alizarin lake and the like can be used.

  Examples of yellow colorants include chrome yellow, benzidine yellow, hansa yellow, naphthol yellow, molybdenum orange, quinoline yellow, and tartrazine.

As the colorant used in the toner of the present invention, dyes and pigments capable of obtaining toners of yellow, magenta, cyan and black colors can be used.
For example, carbon black, lamp black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, Rogmin 6G, lake, chaco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, etc. Any conventionally known dyes and pigments such as dyes and pigments can be used alone or in combination.

  Further, as an external additive, for the purpose of improving the fluidity of the toner, a hydrophobic silica, titanium oxide, alumina, or the like, and a fatty acid metal salt, polyvinylidene fluoride, or the like may be added as necessary.

  Further, when the toner of the present invention is used as a two-component developer, all known carriers can be used. For example, magnetic powder such as iron powder, ferrite powder, nickel powder, glass, and the like. Examples thereof include beads and the like, and those whose surfaces are treated with a resin or the like.

  Examples of the resin powder that can be coated on the carrier in the present invention include a styrene-acrylic copolymer, a silicone resin, a maleic acid resin, a fluorine resin, and a polyester resin epoxy resin.

In the case of a styrene-acrylic copolymer, those having a styrene content of 30 to 90% by weight are preferred.
In this case, if the styrene content is less than 30% by mass, the development characteristics are low, and if it exceeds 90% by mass, the coating film becomes hard and easily peeled, and the life of the carrier is shortened.

Moreover, the resin coating of the carrier in the present invention may contain an adhesion-imparting agent, a curing agent, a lubricant, a conductive material, a charge control agent and the like in addition to the resin.
In the present invention, the carrier core particles coated with the silicone resin may be those conventionally known, for example, ferromagnetic metals such as iron, cobalt and nickel; alloys and compounds such as magnetite, hematite and ferrite; and glass beads. It is done.

The average particle diameter of these core particles is usually 10 to 1000 μm, preferably 30 to 500 μm.
In addition, as usage-amount of a silicone resin, it is 1-10 mass% normally with respect to a carrier core particle.

  The silicone resin used in the present invention may be any conventionally known silicone resin. For example, commercially available KR261, KR271, KR271, KR272, KR275, KR280, KR282, KR285 manufactured by Shin-Etsu Silicone. , KR251, KR155, KR220, KR201, KR204, KR205, KR206, SA-4, ES1001, ES1001N, ES1002T, KR3093 and SR2100, SR2101, SR2107, SR2110, SR2108, SR2109, SR2115, SR2400, SR2410, manufactured by Toray Silicone SR2411, SH805, SH806A, SH840, etc. are used.

As a method for forming the silicone resin layer, a silicone resin may be applied to the surface of the carrier core particles by a spraying method, a dipping method, or the like, as in the past.
The toner suitably used in the image forming apparatus of the present invention includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or elongation reaction in an aqueous solvent.

Hereinafter, the constituent material and the manufacturing method of the toner will be described.
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.

  Dihydric alcohol (DIO) includes alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol, etc.) 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 a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain 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.

  Polyisocyanate compounds (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.); aromatic aliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; 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 polyvalent isocyanate 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 deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 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. When [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 polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group.

  Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester. When reacting (PIC) and when reacting (A) and (B), a solvent may be used if 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 full-color image forming apparatus 100 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 mass ratio of unmodified polyester and 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 mass 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.

  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% by mass, preferably 3 to 10% by mass with respect to the toner.
The colorant can also be used as a master batch combined with a resin.
As the 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.

  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, Nitronine dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E-84 , Phenol-condensate E-89 (above, Orient Chemical Industry Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSYVP2038, copy blue PR of triphenylmethane derivative, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (manufactured by Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, azo face , Sulfonate group, 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 mass with respect to 100 parts by mass of the binder resin.

Preferably, the range of 0.2-5 mass parts is good.
When the amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

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. The effect on high temperature offset is exhibited without applying a release agent such as oil.
Examples of such a wax component include the following.

  Waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and ceresin, and paraffin and 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.

  Further, fatty acid amides such as 12-hydroxystearic amide, stearic amide, phthalic anhydride, chlorinated hydrocarbons, and low molecular weight crystalline polymer resins such as 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.
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 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm.
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 particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

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, that is, repeated copying. Stable image quality can be obtained even if

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 mass parts normally with respect to 100 mass parts of polyester prepolymers, Preferably it is 0-100 mass parts, More preferably, it is 25-70 mass parts.

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 mass of the toner material liquid is usually 50 to 2000 parts by mass, preferably 100 to 1000 parts by mass. If the amount is less than 50 parts by mass, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by mass, 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, eg amphoteric surfactants such as alanine, dodecyl di (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), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M), Unidyne DS-101. DS-102 (Daikin Kogyo Co., Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), 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).

  In addition, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, which is right on the fluoroalkyl group. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), 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 existing on the surface of the toner base particles is in the range of 10 to 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, and trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno There are polymer 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 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, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm.

  When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

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.

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 mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the setting example of the linear velocity is an example, and is not limited to the numerical values of the embodiments. The numerical value of the paper thickness for switching the linear velocity is also an example, and can be set to an appropriate numerical value.

  A device mounted on the process cartridge is arbitrary, and the image carrier (photosensitive member) is not limited to a drum shape, and a belt-like image carrier can also be used. A lubricant coating device having an appropriate configuration can also be employed.

  The configuration of the image forming unit of the image forming apparatus is also arbitrary, and the arrangement order of the color image forming units in the tandem system is arbitrary. In addition to the tandem type, a configuration in which a plurality of developing devices are arranged around one photoconductor is also possible. The present invention can also be applied to a full color machine using three color toners, a multicolor machine using two color toners, or a monochrome apparatus. Of course, the image forming apparatus is not limited to a multifunction peripheral, and may be a printer, a copier, or a facsimile.

  The present invention can be suitably used for image forming apparatuses such as copying machines, printers, and facsimiles.

DESCRIPTION OF SYMBOLS 10 Photosensitive body which is an image carrier 20 Lubricant coating device 21 Solid lubricant 22 Lubricant coating brush roller 23 Lubricant coating blade 30 Cleaning device 40 Charging device 50 Developing device 62 Intermediate transfer belt 65 Secondary transfer roller 70 Optical writing device 90 Fixing device 100 Image forming device 200 Process cartridge

JP 2002-287567 A JP 2002-207397 A JP 2007-003730 A

Claims (15)

An image forming apparatus that visualizes a latent image formed on an image carrier as a toner image by a developing device, transfers the toner image onto a recording material, and fixes the toner image on a surface of the image carrier. In an image forming apparatus provided with a lubricant application device,
The linear velocity of the image carrier is provided to be changeable,
In the low-speed mode in which the image carrier operates at a low linear velocity, the linear velocity of the image carrier before the start of the developing operation corresponding to the next recording material after the transfer operation of the toner image to the preceding recording material is completed. An image forming apparatus comprising control means for controlling to switch to a high speed side linear velocity for a predetermined time.   The image forming apparatus according to claim 1, wherein the predetermined time is a time corresponding to at least one rotation of the image carrier.   The image forming apparatus according to claim 1, wherein the predetermined time is a time corresponding to 10 to 20 rotations of the image carrier.   When the image area ratio to be output is higher than a predetermined threshold, the image carrier is switched to the high-speed side linear velocity. When the image area ratio is less than the predetermined threshold, the image carrier is not switched to the high-speed side linear velocity. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 1, wherein the image carrier is switched to a high-speed side linear velocity according to a combination of an image area ratio to be output and a cumulative continuous output number.   2. The image forming apparatus according to claim 1, wherein a switching operation of the photosensitive member linear velocity is performed when the integration of the image area ratios in one job reaches a predetermined image area ratio.   The image forming apparatus according to claim 1, wherein the image carrier is switched to a high-speed linear velocity according to a type of recording material to be used.   The image forming apparatus according to claim 4, wherein an environmental condition is added to a condition for performing or not performing switching to a high-speed side linear velocity of the image carrier.   The predetermined time is changed according to any one of the image area ratio, the combination of the image area ratio and the cumulative continuous output number, the integrated value of the image area ratio in one job, the type of the recording material, and the environmental conditions. The image forming apparatus according to claim 4, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 1, wherein the lubricant applied to the surface of the image carrier is solidified zinc stearate.   The toner used has a weight average particle diameter of 3 to 8 μm and a ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) is in the range of 1.00 to 1.40. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The shape factor SF-1 of the toner to be used is in the range of 100 to 180, and the shape factor SF-2 is in the range of 100 to 180. Image forming apparatus. The toner is a toner obtained by externally adding fine particles having an average primary particle diameter of 50 to 500 nm on a toner base particle surface and a bulk density of 0.3 g / cm ³ or more, The image forming apparatus according to claim 1.   2. The toner according to claim 1, wherein the toner comprises at least a binder resin, a colorant, and a release agent, and has a glass transition temperature of 45 to 65 ° C. and an outflow start temperature of 90 to 115 ° C. 14. The image forming apparatus according to any one of.   In the toner, 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 is crosslinked and / or extended in an aqueous medium. The image forming apparatus according to claim 1, wherein the toner is a toner obtained by causing the toner to form.

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