JP4554336B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which has such configuration that application of a proper amount of a lubricant is possible, improves the cleaning property of a photoreceptor surface, and prevents occurrence of an abnormal image such as image blur to output a high quality image. <P>SOLUTION: When an image area ratio of a visible image on a photoreceptor 1 surface computed by an image area ratio computing means is less than a predetermined value, toner is input in a non-image-formation region of the photoreceptor 1 surface. When image area ratios in regions divided in the axial direction of the photoreceptor 1 are less than a predetermined value, toner is input in non-image-formation regions in the respective divided regions. When image area ratios in regions divided in the axial direction of the photoreceptor 1 are less than a predetermined value, toner is input in non-image-formation regions only in regions in which the image area ratios are less than the predetermined value among the respective divided regions. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an image forming apparatus for an electrophotographic process such as a copying machine, a printer, and a facsimile machine. More specifically, the present invention relates to an image forming apparatus having a system for supplying a lubricant to a photoconductor by a lubricant applying device.

  An image forming apparatus using an electrophotographic process includes a photoconductor as an image carrier, and charges the surface of the photoconductor by discharging to form an electrostatic latent image by exposing the charged photoconductor surface. A toner is supplied to the electrostatic latent image to make it visible, and the visible image formed on the surface of the photoreceptor is transferred onto the surface of the 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 cleaning blade made of an elastic material such as rubber or a cleaning brush in which synthetic resin fibers are formed in a brush shape is rubbed against the surface of the photosensitive member to remove deposits such as untransferred toner. Known.

  However, the cleaning blade and the cleaning brush as described above have a problem that if they are continuously rubbed with the photosensitive member, they are worn with time and the cleaning performance is deteriorated due to chipping or deformation. Further, since the surface of the photoconductor is also worn, the life is shortened. Therefore, in order to reduce the frictional resistance acting between the photoconductor and these cleaning members and to eliminate problems such as wear of the cleaning member and photoconductor, there is a method of applying a lubricant to the surface of the photoconductor. It has been taken. Also, if a lubricant is applied to the surface of the photoconductor, the coefficient of friction on the surface of the photoconductor decreases, so that a fluidizing agent or a charge control agent added to the toner is applied to the surface of the photoconductor by the contact pressure with the cleaning member. It is possible to prevent so-called filming that is fixed in a film form. Transferability of the toner developed on the photoreceptor is also improved by reducing the adhesive force with the surface of the photoreceptor.

If the amount of lubricant applied to the surface of the photoconductor is too small, uneven coating occurs, cleaning failure occurs in areas where the lubricant is not sufficiently applied, and wear of cleaning members such as a cleaning blade progresses. To do. On the other hand, if the amount of lubricant applied is too large, the surface of the charging roller that is close to or in contact with the surface of the photoreceptor is contaminated, or the lubricant is absorbed in a high-temperature and high-humidity environment, thereby forming on the surface of the photoreceptor. The electrostatic latent image flows and causes image blur. Therefore, it is important to apply an appropriate amount of lubricant to the surface of the photoreceptor.
For example, in Patent Document 1, a fiber density of a brush roller to which a lubricant is applied is defined, a pressure member that pressurizes a solid lubricant toward the brush roller side, and the pressure applied is defined. Proposals have been made to define the amount of biting into the surface of the photoreceptor.

In order to reduce the frictional resistance acting between the photoconductor and the cleaning blade and to eliminate problems such as wear of the cleaning blade and photoconductor, the toner scraped on the surface of the photoconductor by the cleaning blade is used as a lubricant. The method of using as is taken. The toner thus scraped off adheres to the blade tip and serves as a lubricant, and has the effect of reducing the frictional force between the blade tip and the photosensitive drum surface.
For example, in Patent Document 2, the image forming area of the photosensitive drum is divided into a plurality of parts in the main scanning direction, and the gradation values of the image data to be written in the divided areas at the time of image formation are integrated. From each integrated value and the rotation time of the photosensitive drum, a gradation integrated value per unit rotation time is obtained for each divided area, and an area where this is smaller than a certain threshold value is exposed and developed for a predetermined time. By forcibly attaching the toner to the toner, the input of the toner to the photoconductor is adjusted to perform the function as a lubricant.

Japanese Patent Laid-Open No. 10-260614 JP 2000-19920 A

  By the way, in recent years, a demand for higher image quality has been increasing, and in order to realize particularly high-definition color image formation, toner particle diameters and spheroidization have been promoted. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner 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 particle size of the toner, the easier it is to enter this space. Since the rolling friction force is smaller as the invading toner has a shape close to a spherical shape, it starts to roll in the space between the photosensitive member and the cleaning blade, passes through the cleaning blade, and leads to poor cleaning.

As a measure for preventing such a cleaning failure, for example, a method of increasing the contact pressure of the cleaning blade to the photosensitive member is taken. As a result, the frictional force with the surface of the photoreceptor increases, and the cleaning blade is more easily damaged and worn. Further, blade squealing or blade turning caused by irregular vibration of the cleaning blade is likely to occur.
Therefore, it has become more important to apply a lubricant uniformly to the surface of the photoreceptor to reduce the coefficient of friction on the surface of the photoreceptor. In order to apply the lubricant, a lubricant applicator that a brush roller contacts the solid lubricant, scrapes the lubricant, and supplies the lubricant to the surface of the photoreceptor is generally used. However, if no toner is input to the brush roller, the brushing ability of the solid lubricant by the brush is reduced, and the applicability to the photoconductor becomes unstable, and filming on the surface of the photoconductor by the toner and toner additive and It causes the photoconductor film to be scraped. Further, the toner having a small particle diameter and spheroidized as described above has a problem that the cleaning property of the photosensitive member has no margin and a cleaning failure is likely to occur due to an increase in the friction coefficient.

  In view of the above problems, the present invention has a configuration capable of applying an appropriate amount of lubricant, improves the cleaning property of the surface of the photosensitive member, and prevents the occurrence of abnormal images such as image blurring, thereby achieving high quality. An image forming apparatus for outputting an image is provided.

In order to solve the above problems, the present invention is characterized by the following.
1. The present invention relates to an image carrier that carries a latent image, a charging unit that uniformly charges the surface of the image carrier, and an exposure unit that exposes the surface of the charged image carrier based on image data and writes the latent image. A developing unit that supplies toner to the latent image formed on the surface of the image carrier and visualizes the image, an image area calculation unit that calculates an image area of the visible image, and an image carrier having the image area. Image area ratio calculation means for the running area, transfer means for transferring a visible image on the surface of the image carrier to a transfer medium, lubricant application means for applying a lubricant to the surface of the image carrier via a fur brush, and transfer In an image forming apparatus comprising a cleaning unit that cleans the subsequent image carrier surface, when the image area ratio of the visible image of the image carrier surface calculated by the image area ratio calculator is less than a predetermined value, In the non-image area on the surface of the image carrier Characterized in that to input over.
2. The image carrier is a photosensitive member, and when the image area ratio of each region divided in the photosensitive member axial direction is less than a predetermined value, toner is input to a non-image forming region in each divided region. Features.
3. When the image area ratio of each region divided in the photosensitive member axis direction is smaller than a predetermined value, toner is input to the non-image forming region only in a region smaller than the predetermined value among the respective regions.
4). The lubricant is a fatty acid metal salt.

5). In the present invention, the toner used in the image forming apparatus has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) of 1. It is in the range of .00 to 1.40.
6). The toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.
7). 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. It is a toner obtained by making it go.

  According to the present invention, it is possible to stabilize the lubricant scraping ability of the solid lubricant application brush independent of the image area, to prevent application unevenness over the entire surface of the photosensitive member, and to prevent excessive application, and an appropriate amount of lubrication. It is possible to provide an image forming apparatus that has a configuration capable of applying an agent, improves the cleaning properties of the surface of the photoreceptor, prevents an abnormal image such as image blur, and outputs a high-quality image.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The following description is an example of the best mode of the present invention, and it is easy for those skilled in the art to make other embodiments within the scope of the claims by making changes and modifications within the scope of the claims. However, this does not limit the scope of the claims.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to the present invention. Here, a full-color copying machine will be described as an example.
The image forming apparatus 100 includes an image forming unit 300, a paper feeding unit 200, a document reading unit 400, and a document conveying unit 500. The image forming unit 300 includes an image forming unit 10, an exposure device 11, a transfer device 5, and a fixing device 7.
The image forming unit 10 includes four units in parallel for forming four color toner images of black (K), cyan (C), magenta (M), and yellow (Y). Photosensitive members 1K, 1C, 1M, and 1Y are provided at the center of each image forming unit 10, and a charging device, a developing device, a lubricant application device, and a cleaning device are provided around the photoconductors.

The exposure apparatus 11 converts data read by the document reading unit 400 or an image signal sent from the outside such as a PC (not shown), scans the laser beam with a polygon motor, and performs photosensitivity based on the image signal read through the mirror. An electrostatic latent image is formed on the body 1.
The transfer device 5 includes an intermediate transfer belt 50 that sequentially superimposes and holds the toner images formed on the respective photoreceptors 1. The color toner images formed on the intermediate transfer belt 50 are recorded on the recording paper. It is configured to transfer to. In addition, the recording paper may be conveyed by a transfer conveyance belt, and the toner image formed on each photoconductor 1 may be directly transferred to the recording paper.
The fixing device 7 is composed of a belt stretched around a roller having a halogen heater or the like inside and a pressure roller, and applies heat and pressure to the toner on the recording paper at a nip formed by both. Fix the toner image. In addition, a pair of rollers or a pair of belts may be used.
In addition to this, the image forming apparatus 100 includes a double-sided reversing unit 9, a paper discharge tray 8, and the like.

FIG. 2 is an enlarged view showing the image forming unit 10 of FIG.
The photoconductor 1 can be made of amorphous metal having photoconductivity, amorphous metal such as amorphous selenium, or organic compound such as bisazo pigment or phthalocyanine pigment. In consideration of environmental problems and post-treatment after use, a photoreceptor using an organic compound is preferable.
The charging device 2 may be any one of a corona method, a roller method, a brush method, and a blade method. Here, the charging device 2 of a roller method is shown. The charging device 2 includes a charging roller 2a, a charging roller cleaning member 2b that is in contact with the charging roller 2a for cleaning, and a power source (not shown) connected to the charging roller 2a. A high voltage is applied to the charging roller 2a to generate corona discharge with the photosensitive member 1 to uniformly charge the surface of the photosensitive member 1.

The developing device 4 includes a developer carrier 4a that carries a developer and supplies the developer 1 to the photoreceptor 1, a toner supply chamber 4b, and the like. The developer carrier 4a includes a hollow cylindrical developer carrier 4a that is rotatably supported, and a magnet roll fixed coaxially with the developer carrier 4a. The developer is magnetically attracted to the outer peripheral surface of the carrier 4a and conveyed. The developer carrier 4a is electrically conductive and is made of a nonmagnetic member, and is connected to a power source (not shown) for applying a developing bias. A voltage is applied from the power source between the developer carrying member 4a and the photoreceptor 1, and an electric field is formed in the developing region.
A primary transfer unit 51 is provided at a position facing the photoreceptor 1 with the intermediate transfer belt 50 interposed therebetween. The primary transfer means 51 is connected to a power source (not shown), and a voltage is applied when transferring the toner image on the photoreceptor 1 to the intermediate transfer belt 50, so that an electric field is generated between the photoreceptor 1 and the intermediate transfer belt 50. The toner image is transferred electrostatically.

  The cleaning blade 61 and the cleaning brush 62 of the cleaning device 6 are in contact with the photoreceptor 1. The cleaning blade 61 is formed of a rubber such as urethane rubber or silicone rubber in a plate shape.

  The lubricant application device 3 is arranged downstream of the position in which the photosensitive member 1 faces the primary transfer unit 51 in the moving direction of the photosensitive member 1, upstream of the cleaning blade 61, and downstream of the cleaning brush 62. The lubricant applied to the surface of the photoreceptor 1 by the lubricant application device 3 is then extended by the rubbing of the surface of the photoreceptor 1 by the cleaning blade 61 to form a thin layer of lubricant on the surface of the photoreceptor 1. Can do.

  The lubricant application device 3 is mainly composed of a solid lubricant 3 b and an application brush 3 a that contacts the solid lubricant 3 b to scrape off the lubricant and supply it to the surface of the photoreceptor 1. The pressing is a pressing due to its own weight. A configuration using a pressure spring may be used. By pressing, the solid lubricant 3b is scraped off by the application brush 3a, and is transferred from the surface of the application brush 3a to the photosensitive member, and the lubricant is applied to the photosensitive member.

  Residual toner adhering to the surface of the photoreceptor 1 is removed by the cleaning brush 62, but a part thereof is input to the application brush 3 a of the lubricant application device 3. It has been found by the present inventors that the amount of toner input to the application brush 3a at this time has an influence on the amount of the solid lubricant 3b scraped off. That is, if the amount of toner input to the application brush 3a is a predetermined amount, the amount of the solid lubricant 3b to be scraped is stabilized, and a necessary amount of lubricant is applied to the photoconductor 1 so that the cleaning blade 61 is in contact with the photoconductor. By rubbing one surface, it is possible to realize low friction on the surface of the photoreceptor 1. If too much toner is input, the coefficient of friction between the solid lubricant and the brush becomes small, and the amount of the solid lubricant that can be scraped decreases. If too little toner is input, the solid lubricant is scraped, but the lubricant cannot be smoothly transferred from the brush to the photoreceptor.

Therefore, the present inventors capture the image area ratio on the surface of the photoreceptor 1 with a control unit (not shown), forcibly input toner into the non-image forming area, and stable lubricant over the entire surface of the photoreceptor 1. Application was performed.
FIG. 3 is a flowchart showing a toner input process according to the present invention. Hereinafter, the flowchart will be described in detail. When the image forming operation is started, a control unit (not shown) calculates an image area A ′, which is the image area for the latest one image forming operation, and compares it with a predetermined value X. The image area A ′ is an image area A ′ of an image developed by the developing device 4 and formed on the photoreceptor 1 and can be calculated from the following equation.
[Image area A ′] = [count pixel count] × [area of one pixel]
The number of pixels to be written is counted to calculate the number of pixels to be counted. Here, since the area of one pixel is determined in advance, the image area can be known.
Here, it is determined whether or not a predetermined amount of toner has been input to the brush in the latest image. If A ′ ≧ X and a predetermined amount of toner input can be expected, the cumulative calculation counter is reset.
When a predetermined amount of toner input cannot be expected, it is determined how long the state of A ′ <X continues, that is, based on the accumulated rotation time R of the photoconductor not having the predetermined amount of toner input. When the value R of the counter is equal to or smaller than the predetermined value Y, the image forming operation is continued.
When it is larger than the predetermined value Y, it is determined by calculating the image area ratio. The image area ratio is a value A / R obtained by dividing the cumulative image formation area A by the cumulative rotation time R. That is, it is determined whether or not the toner input is insufficient in the long term. Then, the calculated image area ratio (A / R) is compared with the critical value Z of the image area ratio that requires toner input, and if A / R <Z, the toner is forced to the non-image forming area. To supply toner to the application brush 3a so that the solid lubricant 3b is scraped stably. Further, the A and R counters are reset. When this A / R is equal to or greater than the predetermined value Z, the image forming operation is continued.

  Further, by using the above-described toner input process, the surface of the photoreceptor 1 is divided into n (n ≧ 2) in the longitudinal direction of the photoreceptor, and the image area ratio for each divided area is captured, and the image area ratio is When the value is smaller than the predetermined value, the toner is forcibly input in the non-image forming area in each divided area, the toner is supplied to the application brush 3a of the lubricant application device 3, and the solid lubricant 3b is stably supplied. It can also be scraped off.

  Further, the surface of the photoconductor 1 is divided into n (n ≧ 2) in the longitudinal direction of the photoconductor, and the image area ratio of each divided area is captured, and when the image area ratio is smaller than a predetermined value, Of these, the toner is forcibly input only in the non-image forming area to an area smaller than a predetermined value, and the toner is supplied to the applying brush 3a of the lubricant applying device 3 so that the solid lubricant 3b is scraped stably. You can also.

  The solid lubricant 3b is, for example, a fatty acid such as lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate, zinc linolenate, etc. A metal salt formed into a block shape is used. In particular, a metal stearate having a large effect of reducing the friction of the photoreceptor 1 and further zinc stearate are more preferable.

Brush thickness of the fibers of the application brush 3a is preferably 3 to 8 deniers, the density of the brush fibers 20000-100000 present / inch ² is preferable. If the thickness of the brush fiber is too thin, the brush roller 3a is liable to fall down when the brush roller 3a comes into contact with the surface of the photoconductor 1. Conversely, if the brush fiber is too thick, the density of the fiber cannot be increased. In addition, if the density of the brush fibers is low, the number of brush fibers in contact with the surface of the photoreceptor 1 is small, so that the lubricant cannot be uniformly applied. The gap becomes small, and the amount of the lubricant powder that has been scraped off decreases, resulting in an insufficient amount of coating.
Accordingly, the application brush 3a having the above-mentioned setting range having the thickness of the brush fiber for preventing the hair from collapsing and the density of the brush fiber capable of efficiently applying the lubricant uniformly. The brush fiber is a conductive fiber such as carbon-containing acrylic and is grounded.

  By providing the image forming apparatus with the toner input process as described above, the solid lubricant 3b is stably scraped off by the brush roller, and a uniform thin film of lubricant is formed on the surface of the photoreceptor 1 without causing uneven coating. can do. Thereby, the cleaning blade 61 and the surface of the photoreceptor 1 can be prevented from being worn, and the transfer residual toner remaining on the surface of the photoreceptor 1 can be cleaned well.

Further, the lubricant application device 3 is integrally supported including the photosensitive member 1 and any means selected from the charging device 2, the developing device 4, and the cleaning device 6, and is detachably attached to the image forming apparatus main body. The process cartridge can be formed. With this process cartridge, the cleaning performance of the surface of the photoreceptor 1 can be maintained for a long period of time, and a process cartridge that does not cause deterioration in image quality can be obtained.
In addition, the process cartridge is advantageous in terms of maintenance, and if a failure occurs due to the photoreceptor 1, the lubricant application device 3, the cleaning device 6, the charging device or the developing device 4, the cartridge is replaced. By simply doing this, the original state can be recovered at an early stage, so that the service time can be shortened. In addition, by making the photoconductor 1 easy to clean, it greatly contributes to extending the life of the process cartridge.

The image forming apparatus of the present invention is particularly effective when using a toner having a reduced particle size and a spherical shape as shown below.
The toner used in the developing device 4 has a volume average particle diameter of 3 to 8 μm, and the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1.00 to 1.40. It is preferable that it exists in the range.
By using a toner having a small particle diameter, the toner can be densely attached to the latent image. However, when the volume average particle diameter is smaller than the range of the present invention, in the two-component developer, the toner is fused to the surface of the magnetic carrier during long-term stirring in the developing device 4, and the charging ability of the magnetic carrier is lowered. When used as a component developer, toner filming on the developer carrier 4a and toner fusion to a member such as a blade for thinning the toner are likely to occur. On the contrary, when the volume average particle diameter of the toner is larger than the range of the present invention, it becomes difficult to obtain a high-resolution and high-quality image, and when the balance of the toner in the developer is performed. In many cases, the variation in toner particle size becomes large.
Further, by narrowing the particle size distribution, the toner charge amount distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased. However, it is not preferable that Dv / Dn exceeds 1.40 because the charge amount distribution becomes wide and the resolving power decreases.
The average particle size and particle size distribution of the toner can be measured using a Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, a Coulter counter TA-II type was used, connected to an interface (manufactured by Nikka Giken) and a personal computer (PC9801: manufactured by NEC) to output the number distribution and volume distribution.

  In the toner as described above, the ratio of the wax added to the toner to improve the releasability or the inorganic fine particles to improve the fluidity is small in the particle size. As a result, it is higher than the conventional toner. These additives are the cause of the adhered substances generated on the photoreceptor 1. Therefore, by providing the toner input process of the present invention, a uniform thin film of lubricant can be formed over the entire surface of the photoreceptor 1, and the adhesion force of these adhering substances to the surface of the photoreceptor 1 can be reduced. In addition, the frictional force acting between the surface of the photosensitive member 1 and the cleaning blade 61 of the cleaning device 6 can be reduced so that the cleaning can be performed satisfactorily.

The toner used in the developing device 4 preferably has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.
FIG. 4 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 toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger 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 on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100π / 4) Expression (2)
When the value of SF-2 is 100, unevenness does not exist on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.
When the shape of the toner is close to a spherical shape, the contact between the toner and the toner or the toner and the photoreceptor 1 is close to a point contact, so that the adsorbing force between the toners is weakened and the fluidity is increased. The attracting force with the body 1 is also weakened, and the transfer rate is increased. On the other hand, since spherical toner tends to enter the gap between the cleaning blade 61 and the photoreceptor 1, the toner shape factor SF-1 or SF-2 is preferably large to some extent. Further, when SF-1 and SF-2 are increased, toner is scattered on the image and the image quality is lowered. For this reason, it is preferable that SF-1 and SF-2 do not exceed 180.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.) and introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) for analysis. And calculated.

  The toner suitably used in the image forming apparatus of the present invention is, for example, 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. Is a toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. In the following, description will be given with examples of toner constituent materials and manufacturing methods.

(Modified polyester)
The toner according to the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

The urea-modified polyester is produced as follows.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. As trihydric or higher polyhydric alcohol (TO), 3 to 8 or higher polyhydric aliphatic alcohol (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.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; 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 modified polyester (i) used in the present invention is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10,000, and if it is less than 1,000, the elongation reaction hardly occurs and the elasticity of the toner is small, and as a result, the resistance to hot offset deteriorates. On the other hand, if it exceeds 10,000, the problem in production becomes high in the case of a decrease in fixability, particle formation or pulverization. The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.
In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
The molecular weight of the polymer produced can be measured using gel permeation chromatography (GPC) with THF as a solvent.

(Unmodified polyester)
In the present invention, not only the modified polyester (i) is used alone, but also the unmodified polyester (ii) can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to the single use. Examples of (ii) include polycondensates of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC), which are the same as the polyester component (i), and preferred ones are also the same as (i). . Further, (ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, for example, may be modified with a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. When the weight ratio of (i) 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 peak molecular weight of (ii) is 1000-10000 normally, Preferably it is 2000-8000, More preferably, it is 2000-5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. As for the acid value of (ii), 1-5 are preferable, More preferably, it is 2-4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C, preferably 55 to 65 ° C. If it is less than 35 ° C., the heat-resistant storage stability of the toner deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low as compared with known polyester-based toners. Show.
The glass transition point (Tg) can be measured with a differential scanning calorimeter (DSC).

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing 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 weight, preferably 3 to 10% by weight, based on the toner.

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

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenol-condensate E-89 (above, manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.
The amount of the 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. The amount is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. 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. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~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 rising characteristics. It can be considered large. However, when the added 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 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

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

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage 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, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.).
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, 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.

Further, the toner according to the present invention has a substantially spherical shape and can be represented by the following shape rule.
FIG. 5 is a diagram schematically showing the shape of the toner according to the present invention. In FIG. 5, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present invention has a major axis and a minor axis. Ratio (r2 / r1) (see FIG. 5B) is 0.5 to 1.0, and the ratio of thickness to short axis (r3 / r2) (see FIG. 5C) is 0.7 to 1.0. It is preferable to be in the range of 1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.
Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

The toner produced as described above can also be used as a one-component magnetic toner that does not use a magnetic carrier or a non-magnetic toner.
When used in a two-component developer, it may be used by mixing with a magnetic carrier, and the magnetic carrier is a ferrite containing a divalent metal such as iron, magnetite, Mn, Zn, Cu, A volume average particle size of 20 to 100 μm is preferred. If the average particle size is less than 20 μm, carrier adhesion is likely to occur on the photoreceptor 1 during development, and if it exceeds 100 μm, the miscibility with the toner is low and the charge amount of the toner is insufficient, resulting in poor charging during continuous use. Cheap. In addition, Cu ferrite containing Zn is preferable because of its high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus 100. The resin for coating the magnetic carrier is not particularly limited, and examples thereof include silicone resin, styrene-acrylic resin, fluorine-containing resin, and olefin resin. In the manufacturing method, the coating resin may be dissolved in a solvent, sprayed into a fluidized bed and coated on the core, or the resin particles are electrostatically attached to the core particles and then thermally melted for coating. It may be a thing. The resin to be coated has a thickness of 0.05 to 10 μm, preferably 0.3 to 4 μm.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the present invention. FIG. 2 is an enlarged view showing an image forming unit 10 in FIG. 1. 6 is a flowchart illustrating a toner input process according to the present invention. FIG. 6 is a diagram schematically illustrating the shape of a toner in order to explain the shape factor SF-1 and the shape factor SF-2. FIG. 3 is a diagram schematically illustrating the shape of a toner according to the present invention.

Explanation of symbols

1 Image carrier (photoreceptor)
2 Charging means (charging device)
2a Charging roller 2b Charging roller cleaning member 3 Lubricant application means (lubricant application device)
3a coating brush 3b solid lubricant 4 developing means (developing device)
4a Developer carrier 4b Toner supply chamber 5 Transfer means (transfer device)
50 Intermediate transfer belt 51 Primary transfer means 6 Cleaning device 61 Cleaning blade 62 Cleaning brush 62a Flicker 7 Fixing means (fixing device)
11 Exposure means (exposure device)
100 Image forming apparatus

Claims (11)

An image carrier for carrying a latent image;
Charging means for uniformly charging the surface of the image carrier;
Exposure means for exposing the surface of the charged image carrier based on image data and writing a latent image;
Developing means for supplying a toner to the latent image formed on the surface of the image bearing member to visualize the latent image;
Image area calculating means for calculating the image area of the visible image;
Image area ratio calculation means for the travel time of the image carrier of this image area,
Transfer means for transferring a visible image on the surface of the image carrier to a transfer medium;
A lubricant application means for applying a lubricant to the surface of the image carrier via a fur brush;
In an image forming apparatus comprising a cleaning means for cleaning the surface of an image carrier after transfer,
When the image area ratio of the visible image on the surface of the image carrier calculated by the image area ratio calculator is smaller than a predetermined value, toner is input in a non-image forming area on the surface of the image carrier. Image forming apparatus. The image forming apparatus according to claim 1.
The image carrier is a photosensitive member, and when the image area ratio of each region divided in the photosensitive member axial direction is less than a predetermined value, toner is input to a non-image forming region in each divided region. An image forming apparatus. The image forming apparatus according to claim 2.
When the image area ratio of each region divided in the photosensitive member axis direction is smaller than a predetermined value, toner is input only in a region smaller than the predetermined value in each region in a non-image forming region. Forming equipment. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the lubricant is a fatty acid metal salt. The image forming apparatus according to claim 1,
The toner used in the developing unit has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1.40. An image forming apparatus characterized by being in the range. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the toner used in the developing unit has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. The image forming apparatus according to claim 1,
The toner used in the developing means crosslinks a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous medium. And / or a toner obtained by an extension reaction. A toner used in the image forming apparatus according to claim 1,
A toner having a weight average particle diameter of 10 μm or less and a ratio (dispersity) of the weight average particle diameter to the number average particle diameter in the range of 1.00 to 1.40. The toner according to claim 8.
The toner has an average circularity in a range of 0.95 to 1.00. The toner according to claim 8 or 9, wherein
The appearance of the toner is almost spherical,
The ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0. And a toner satisfying the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3. The toner according to any one of claims 8 to 10,
The toner is obtained by crosslinking and / or crosslinking a toner material solution obtained by dissolving or dispersing 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 in an aqueous medium. A toner characterized by an extension reaction.

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