JP2008165060A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant application device having a mechanism of preventing generation of abnormal images such as a hollow portion, image blur and uneven toner deposition of a transferred image. <P>SOLUTION: The lubricant application device is equipped with a lubricant applying member 50 that can move while contacting the surface of an image carrier movable in a predetermined direction and supplies a lubricant while moving after contacting the lubricant and then contacting the image carrier; and blade members 103, 104 interposing the lubricant applying member 50 at an upstream side and a downstream side of the image carrier along the moving direction, each member in contact with the image carrier. The blade member 104 in the blade members 103, 104, at the position in the downstream side of the lubricant applying member 50 in the moving direction of the image carrier is a lubricant uniformizing member to uniformize the lubricant applied on the image carrier surface by the lubricant applying member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly, to a lubricant application mechanism for a photoreceptor used as a latent image carrier or a transfer body to which images carried on the photoreceptor are sequentially transferred.

In an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a printing machine, an electrostatic latent image formed on a photosensitive member, which is a latent image carrier, is processed with a visible image, and the visible image is transferred. A sheet-like recording medium (hereinafter referred to as a recording sheet) such as a recording paper or an OHP film that is carried is used for fixing to a fixing device to obtain a copy or a printed output.

The image formed on the photoconductor may be a full-color image as well as a monochrome image.
In the transfer process when forming a full-color image, in addition to the configuration in which the image of each color is sequentially transferred in the process of moving the recording sheet to the image forming unit in which a plurality of photoconductors are juxtaposed, an intermediate transfer member such as a belt is used. There is a configuration in which a multi-color image such as a full color image can be formed by performing a primary transfer using a secondary transfer and performing a secondary transfer in which a superimposed image obtained by the primary transfer is collectively transferred to a recording sheet (for example, Patent Document 1).

  In such an image forming apparatus, in order to prevent transfer defects during primary transfer and secondary transfer of each color toner image, a lubricant is applied to the surface of the image carrier or intermediate transfer member to attach it to the toner. A technique for reducing the wearing force is already known.

As a configuration for applying the lubricant, the application brush is rotated while being in contact with a solid lubricant (hereinafter referred to as a solid lubricant), and the lubricant is transferred onto the application brush, whereby an image carrier or an intermediate transfer member is used. Have been proposed (for example, Patent Documents 2 and 3).
As a result, the coefficient of static friction μs with respect to the toner on the surface of the member to be coated is reduced, so that the toner image can be satisfactorily transferred to the transfer material side.

  On the other hand, untransferred toner or paper dust may remain on the photosensitive member or the transfer member, and it is well known that cleaning for removing these foreign matters is performed. Cleaning is a treatment for preventing the toner image from being transferred well even when a lubricant is applied, so that a part of the image is not transferred even though the lubricant is applied. In other words, the so-called “worm-eating” phenomenon that is caused by the lack of toner in the image area, the phenomenon that is called “image blur” due to the lack of toner in the image area, and the uniform transfer of toner on the image transferred to the recording medium. It is possible to suppress the occurrence of a phenomenon in which an image referred to as “buzzy” is obtained.

The following two patterns can be considered for the positional relationship on the coated member in the two steps of applying the lubricant after the transfer and cleaning the residual toner. That is, there are two patterns, a relationship of cleaning after application where the lubricant is applied first and cleaning after, and a relationship of application after cleaning where the lubricant is applied first and cleaning is applied after. Since the mechanism of abnormal image generation differs depending on each pattern, description will be made separately for each pattern below.
First, the mechanism of abnormal image generation in the post-application cleaning pattern will be described. FIG. 7 is a partially enlarged view of the vicinity of the lubricant application portion having the above-described post-application cleaning configuration. As shown in this figure, an application brush (also indicated by reference numeral B) as an application member is in contact with the surface of an application belt (denoted by reference numeral A for convenience) that is an image carrier or intermediate transfer member. A cleaning blade (also denoted by reference numeral C) is in contact with the surface of the belt A to be coated on the downstream side in the moving direction.
Thus, the lubricant D is applied to the surface of the belt A to be applied by the application brush B, and then the surface is cleaned by the cleaning blade C.
In such post-application cleaning, the lubricant is applied to the surface of the member to be applied in a state where the toner remains without being removed. Here, the portion corresponding to the character portion of the image originally carried on the surface of the coated member A has a lot of residual toner on the surface of the coated member even after transfer to the transfer material, and the portion other than the character portion is There is substantially no residual toner. Since a large amount of residual toner is scraped off by the application brush and a cleaning blade at the cleaning position, the amount of lubricant on the surface of the applied member after passing through the cleaning position is increased. The application amount is uneven. In particular, when the same image is output continuously, the portion where the residual toner is large on the surface of the member to be coated is always the same, and thus such a bias becomes remarkable. Further, since residual toner adheres to an application member such as an application brush, the application brush becomes dirty, and it becomes difficult to continue to apply the lubricant uniformly over a long period of time. If a uniform lubricant layer cannot be formed on the surface of the coated member, the surface static friction coefficient μs may be biased or not low enough to transfer toner, resulting in uneven transfer, and insects. It becomes an abnormal image such as biting, image blur, and blurring.

Next, the mechanism of abnormal image generation in the post-cleaning application pattern will be described. FIG. 8 is a partially enlarged view of the vicinity of the lubricant application portion having the above-described post-cleaning application configuration. As shown in this figure, an application brush B as an application member is provided on the surface of an application belt A that is an image carrier or an intermediate transfer body so as to abut on the surface of the application belt A in the direction of surface movement. The cleaning blade C is in contact therewith.
As a result, the surface of the belt A to be coated is cleaned by the cleaning blade C, and then the lubricant is applied by the coating brush B.
When such post-cleaning application is performed, the lubricant after application is not scraped off by the application brush and the cleaning blade, so that it is possible to prevent problems with the post-application cleaning configuration. However, if the surface of the member to which the lubricant is applied enters the transfer position as it is and the transfer is performed, an abnormal image may occur even though the static friction coefficient μs of the surface is within an appropriate range. I understood. This is because the lubricant particles are not fine enough to form a uniform layer just after being applied, and therefore the layer thickness is uneven on the surface of the coated member, which affects the transferability of the toner. understood. If a uniform lubricant layer cannot be formed on the surface of the member to be coated, the static friction coefficient μs of the surface will not be uniform, or will not be low enough to transfer the toner, resulting in transfer unevenness and insect bite. An abnormal image such as an image blur or a blur is generated.
The structure for uniformly applying the lubricant to the member to be coated when applying the lubricant is to lubricate the image carrier by increasing the density of the hair of the application brush for applying the lubricant. Applying to the supported member after uniformizing the amount of the lubricant carried on the lubricant carrying member (for example, Patent Document 4) enabling uniform application of the agent or on the lubricant carrying member According to the above, there is one that enables uniform application of a lubricant (for example, Patent Document 5).

JP 2006-078679 A Japanese Patent Laid-Open No. 06-332324 Japanese Patent Laid-Open No. 10-254295 Japanese Patent Laid-Open No. 10-260614 JP 07-295451 A

However, in the configuration used for uniformly applying the lubricant as disclosed in Patent Document 4, the surface of the supported member is cleaned after the lubricant is applied. There is a possibility that adhesion of residual toner cannot be completely prevented.
Further, the configuration disclosed in Patent Document 5 performs uniform application of the lubricant for the purpose of improving the cleaning performance of the supported member to which the lubricant is applied, and prevents the above-described problems on the transferred image. It has not been studied to the point that the above-mentioned problems can be prevented.

  In other words, any of the patent documents only solves the problem at the time of supplying the lubricant, that is, presents a solution concerning the inability to uniformly supply the lubricant, and keeps the applied lubricant in a uniform state. There is no reduction in this regard. For this reason, the generation of abnormal images such as worm eaters, image blurs, and blurring remains due to changes in the coefficient of static friction on the image carrier.

  An object of the present invention is to provide a structure capable of reliably preventing the occurrence of an image on a transfer image integrally with a worm-eating, image blur, or blur in view of the problems in the conventional lubricant application device and the image forming apparatus using the same. It is an object of the present invention to provide a lubricant coating apparatus and an image forming apparatus provided with the above.

In order to achieve the above object, the present invention comprises the following arrangement.
(1) The lubricant can be moved while being in contact with the surface of the image carrier that can move in a predetermined direction, and after the lubricant is brought into contact with the image carrier, the lubricant is moved in the order of contact with the image carrier. Lubrication provided with a lubricant application member that can be supplied to the carrier, and blade members that contact the image carrier on the upstream side and the downstream side, respectively, in the moving direction of the image carrier across the lubricant application member In the agent coating apparatus, among the blade members, the blade member located on the downstream side of the lubricant application member in the moving direction of the image carrier is configured to apply the lubricant applied to the surface of the image carrier by the lubricant application member. A lubricant application device, characterized in that it is a smoothing agent uniformizing member.

  (2) The lubricant applying apparatus according to (1), wherein the blade member is formed of a member that can be bent or elastically deformed in contact with the image carrier.

  (3) An image forming apparatus using the lubricant application device according to (1) or (2).

  (4) The blade member is provided as a first cleaning member and a second cleaning member on the upstream side and the downstream side of the lubricant application member in the moving direction of the image carrier, respectively. The image forming apparatus according to 3). .

  (5) Among the blade members, a blade member located on the downstream side in the moving direction of the image carrier with the lubricant application member interposed therebetween serves as both the cleaning member and the lubricant uniformizing member. (39) The image forming apparatus as described in (39) or (4).

  (6) The first and second cleaning members are counter blades facing the image carrier in the counter direction, and the moving direction of the image carrier at the position of contact with the image carrier is opposite to the counter blade. The inclination angle of the leading edge of the first cleaning member is α °, and the inclination angle of the leading edge of the second cleaning member with respect to the moving direction of the image carrier at the position of contact with the image carrier is β The image forming apparatus according to any one of (4) to (5), wherein a relationship of α ≦ β is set when °.

  (7) A latent image carrier and a transfer body positioned on a side to which an image carried on the latent image carrier is transferred are used as the image carrier (3) to (6). The image forming apparatus according to any one of the above.

  (8) The toner 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) in the range of 1.0 to 1.40. (4) The image forming apparatus as described in any one of (3) to (7).

  (9) The toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 190 is used as the toner (3) to (8) The image forming apparatus according to any one of the above.

  (10) As the toner, a toner material liquid in which a polyester prepolymer having a functional group containing at least 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 3, wherein the image forming apparatus is a toner obtained by a reaction.

  (11) The image forming apparatus according to any one of (3) to (10), wherein a substantially spherical toner is used as the toner.

  (12) As the above toner, Keio is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1> r2> r3), and a ratio (r2 / r1) between the major axis r1 and the minor axis r2 is determined. (3) The ratio (r3) / r2) of the thickness r3 to the minor axis r2 is in the range of 0.7 to 1.0. The image forming apparatus according to any one of (11) to (11).

  According to the present invention, since the lubricant applied to the surface of the image carrier is leveled by the lubricant uniformizing member, uneven application on the surface of the image carrier can be eliminated and toner adhesion can be weakened. Therefore, it is possible to improve the transferability of toner and prevent the occurrence of abnormal images. In particular, when the surface of the image carrier is cleaned before reaching the lubricant application position, the lubricant application surface on the surface of the image carrier is cleaned to prevent a non-uniform application state due to foreign matter or the like. Therefore, the transferability can be improved efficiently.

  Further, according to the present invention, since the cleaning members are provided by the blades on the upstream side and the downstream side in the moving direction of the image carrier with the lubricant application position interposed therebetween, even if a cleaning abnormality occurs on the upstream side, the downstream side A clean state can be maintained by cleaning at. As a result, it is possible to prevent the occurrence of abnormal images due to the presence of foreign matter on the surface of the image carrier, and moreover, since the lubricant uniformizing member is also used as a configuration therefor, the transfer can be performed without requiring a special configuration. Can be prevented.

  Further, according to the present invention, when the first and second cleaning members are provided, the inclination angle of the leading edge with respect to the image carrier between the cleaning portions is set, and in particular, the inclination of the downstream cleaning member is set. By increasing the angle, it is possible to prevent entrainment following the movement of the image carrier on the first cleaning member side and to prevent deterioration of the cleaning property on the upstream side.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an image forming apparatus 1 to which a cleaning device according to the present invention is applied.
An image forming apparatus 1 shown in FIG. 1 has a tandem configuration in which a plurality of photoreceptors as latent image carriers capable of forming a color image corresponding to color separation are juxtaposed, and toner formed on each photoreceptor. The color printer is capable of forming a multicolor image by superimposing and transferring an image onto an intermediate transfer member and then transferring the superimposed image onto a sheet such as recording paper. In the present invention, the image forming apparatus is not limited to a color printer, but of course includes a color copying machine, a facsimile machine, and a printing machine.
In the case of this embodiment, the lubricant application device described below is a photosensitive member corresponding to an image carrier or a transfer member used when transferring an image carried on the photosensitive member. Preface what is provided as a target.

In FIG. 1, in a color printer 1, an image forming unit 1A is positioned at a central portion in the vertical direction, a document feeding unit 1B is provided below the image forming unit 1A, and an original document table 1C1 is provided above the image forming unit 1A. Each of the scanning units 1C is arranged.
In the image forming unit 1A, a transfer unit composed of an intermediate transfer belt 2 is disposed as an intermediate transfer member having a horizontally extending surface, and the intermediate transfer belt 2 has a complementary color relationship with a color separation color. A configuration for forming an image of a certain color is provided.

The image forming unit 1A is provided with an image forming unit capable of forming an image with toners of complementary colors (yellow, magenta, cyan, black), and each image forming unit is a photosensitive member capable of carrying an image. The bodies 3B, 3C, 3M, and 3Y are juxtaposed along the extended surface of the intermediate transfer body 2. In the following description, in the case of contents common to all the photoconductors, the photoconductor is denoted by reference numeral 3.
Each of the photoconductors 3B, 3C, 3M, and 3Y is composed of a drum that can rotate in the same direction (counterclockwise in FIG. 1). A device 4, a writing device 5, a developing device 6, a primary transfer device 7 which is one of transfer bias applying means, and a cleaning device 8 are arranged (for the sake of convenience, the reference numerals of the respective devices are used for the photosensitive member 3B). B is shown).

  The intermediate transfer belt 2 corresponds to a primary transfer unit to which a visible image from an image forming unit including each photoconductor is sequentially transferred. The intermediate transfer belt 2 is wound around a plurality of rollers 2A to 2C and is connected to the photoconductor. A roller 2C, which is configured to be movable in the same direction at the facing position and is different from the rollers 2A and 2B constituting the stretched surface, faces the secondary transfer device 9 with the intermediate transfer belt 2 interposed therebetween. Due to the installation space of the intermediate transfer belt 2, a part of the extended surface between the portions wound around the roller indicated by reference numeral 2 </ b> A and the roller indicated by reference numeral 2 </ b> B is extended in the horizontal direction. An extension tension is applied by a tension roller corresponding to a back pressure application member indicated by reference numerals 2D, 2E, and 2F located at the end of the part.

  The secondary transfer device 9 includes a transfer belt 9C that is wound around the charging drive roller 9A and the driven roller 9B and is movable in the same direction as the intermediate transfer belt 2 at the secondary transfer position where the secondary transfer device 9 is located. The multi-color image superimposed on the intermediate transfer belt 2 in the process of transporting the recording sheet while electrostatically attracting it by charging the transfer belt 9C with the charging drive roller 9A can be transferred by single transfer or carried by a single color. Each image can be transferred to a recording sheet.

A recording sheet is fed from the paper feeding unit 1B to the secondary transfer position.
The paper feed unit 1B includes a plurality of paper feed cassettes 1B1, a plurality of transport rollers 1B2 arranged in a transport path for recording sheets fed from the paper feed cassette 1B1, and a registration roller 1B3 positioned in front of the secondary transfer position. I have. In this embodiment, in addition to the conveyance path of the recording sheet fed out from the sheet feeding tray 1B1, a recording sheet of a type not stored in the sheet feeding cassette 1B1 is fed to the sheet feeding unit 1B toward the secondary transfer position. This configuration includes a manual feed tray 1A1 and a feeding roller 1A2 provided with a part of the wall surface of the image forming unit 1A that can be turned up and down.
In the middle of the conveyance path of the recording sheet from the sheet feeding cassette 1B1 to the registration roller 1B3, the conveyance path of the recording sheet fed out from the manual feed tray 1A1 joins, and the recording sheet fed from any conveyance path is also a registration roller. Registration timing is set by 1B3.

  The writing device 5 (in FIG. 1, the writing light for forming a black image is indicated by reference numeral 5B for the sake of convenience) is an image obtained by scanning the document on the document table 1C1 in the document scanning unit 1C. The writing light is controlled by the information or image information output from a computer (not shown) to form an electrostatic latent image corresponding to the image information on the photoreceptors 3B, 3C, 3M, and 3Y.

  The document scanning unit 1C is provided with a scanner 1C2 that exposes and scans the document on the document table 1C1, and an automatic document feeder 1C3 is disposed on the upper surface of the document table 1C1. The automatic document feeder 1C3 has a configuration capable of reversing the document fed on the document table 1C1, and can perform scanning on both sides of the document.

  An electrostatic latent image on the photosensitive member 3 (members indicated by reference numerals 3B, 3C, 3M, and 3Y in FIG. 1) formed by the writing device 5 is indicated by reference numeral 6B in FIG. 1 for convenience. ) To be subjected to a visible image processing and primary transfer to the intermediate transfer belt 2. When the toner images for the respective colors are superimposed and transferred onto the intermediate transfer belt 2, the secondary transfer device 9 performs secondary transfer on the recording sheet at once.

The unfixed image carried on the surface of the recording sheet that has been secondarily transferred is fixed by the fixing device 11. Although not described in detail, the fixing device 11 includes a belt fixing structure including a fixing belt heated by a heating roller and a pressure roller that contacts and contacts the fixing belt, and the contact between the fixing belt and the pressure roller. By providing the area, that is, the nip area, the heating area for the recording sheet can be expanded as compared with the fixing structure of another roller type.
The recording sheet that has passed through the fixing device 11 is switched in the transport direction by a transport path switching claw 12 disposed behind the fixing device 11, and is transported toward the paper discharge tray 13 and reversely transported. A transport direction is selected for the path RP.

  In the color printer 1 having the above-described configuration, the document placed on the document table 1C1 is exposed and scanned, or the image of the image information from the computer is used for statically charging the photosensitive member 3. After the electrostatic latent image is formed and the electrostatic latent image is subjected to visible image processing by the developing device 6, the toner image is primarily transferred to the intermediate transfer belt 2.

  The toner image transferred to the intermediate transfer belt 2 is transferred as it is to the recording sheet fed out from the paper feed unit 1B in the case of a single color image, and the primary transfer is repeated in the case of a multicolor image. And then secondarily transferred to the recording sheet at once. The recording sheet after the secondary transfer is fixed with an unfixed image by the fixing device 11 and then fed to the paper discharge tray 13 or reversed and fed again toward the registration roller 1B3.

  In FIG. 1, although not shown in detail, the intermediate transfer belt 2 includes a base layer composed of a base portion made of a material that hardly stretches, such as a fluorine-based resin having a small elongation or a rubber material having a large elongation, and a canvas, and the like. And an elastic layer made of fluorine-based rubber or acrylonitrile-butadiene copolymer rubber provided on the upper surface. The surface of the elastic layer is provided with a coat layer that is coated with a fluororesin to improve smoothness.

The intermediate transfer belt 2 is wound around support rollers 2A, 2B, a roller 2C having a backup function at the secondary transfer position, and tension rollers 2D, 2E, 2F functioning as back pressure applying members, respectively. It is driven by rotation in the counterclockwise direction.
A surface extended between the support rollers 2A and 2B, that is, a plane having no curvature, faces the photoreceptors 3B, 3Y, 3C, and 3M of each image forming unit. A transfer roller 2D for electrostatically transferring a visible image on the photoconductor is disposed at a position facing each photoconductor with the intermediate transfer belt 2 interposed therebetween.

The registration roller 1B3 used for feeding the recording sheet toward the secondary transfer position is generally used while being grounded, but a bias may be applied to remove paper dust from the recording sheet. Is possible.
For example, a bias is applied using a conductive rubber roller. The surface is a conductive NBR rubber having a diameter of 18 mm and a thickness of 1 mm. The electrical resistance is about 10E9Ω (10 ⁹ Ωcm) as the volume resistance of the rubber material. The applied voltage is about −800V applied to the toner transfer side (front side), and the voltage of about + 200V is applied to the back side of the paper. To do. Generally, in the intermediate transfer system, it is difficult for paper dust to move to the photoconductor, so that it is not necessary to consider paper dust transfer and may be grounded. Further, a DC bias is applied as the applied voltage, but this may be an AC voltage having a DC offset component in order to more uniformly charge the sheet. Thus, the paper surface after passing through the registration roller 49 to which a bias is applied is slightly charged on the negative side. Therefore, in the transfer from the intermediate transfer body 10 to the sheet, there are cases where the transfer conditions are changed and the transfer conditions are changed as compared with the case where no voltage is applied to the registration roller 49.

  The cleaning device is also provided for the intermediate transfer belt 2 separately from each photosensitive member, and as shown by reference numeral 10 in FIG. 1, a stretching roller 2E that functions as a back pressure applying member of the intermediate transfer belt 2. 2F.

The toner used in the color printer 1 of the present embodiment has a small diameter, narrow particle size distribution, and spheroidization (true sphere) using a polymerized toner in order to cope with recent colorization and high image quality associated therewith. It has become mainstream.
The distribution of toner with a small diameter and a narrow particle diameter is advantageous for high-resolution development, and the spheroidization (true sphere) is advantageous for transfer efficiency, and thereby the image quality such as the sharpness of the toner image is remarkably improved.

However, reducing the particle size of the toner increases the specific surface area and increases the adhesion force of the toner per unit weight to the surface of the image carrier, which makes it difficult to clean the surface of the image carrier. Further, the reduction in the toner particle size deteriorates the fluidity of the toner and requires a larger amount of additive, which may cause chipping and abrasion of the cleaning blade, local streak scratches on the surface of the image carrier, and the like. It is known to be.
In addition, when the sphericity of the toner is increased, the above-described blade counter contact method generally used in the related art increases the amount of toner passing through the blade, so that it is necessary to increase the contact pressure more than before. Increasing the pressure reduces the margin against edge chipping due to the local shearing force of the blade.

Next, toner that is preferably used for the color printer 1 of the present embodiment will be described.
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40.
The closer (Dv / Dn) 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.

  The toner shape factor SF-1 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. 3 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 expressed 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) Equation 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) Equation 2
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of 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 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

The toner suitably used in the image forming apparatus of the present invention is a water-based 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 a solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.
(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Trivalent or higher polyvalent carboxylic acid
Examples of (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.

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

The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.
In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.
(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, 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 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 together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.
(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSYVP2038, 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 (manufactured by Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, azo face And other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.
The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.
(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. 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, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.
(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 −3 to 2 μm, and particularly preferably 5 × 10 −3 to 0.5 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m <2> / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.

  Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle size 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, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. .

  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 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. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Smoke), MegaFuck 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.

The toner according to the present invention has a substantially spherical shape and can be represented by the following shape rule.
FIG. 2 is a diagram schematically showing the shape of the toner of the present invention. In FIG. 3, 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. 3B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 3C) 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.

On the other hand, in this embodiment, there is provided a lubricant application device capable of applying a lubricant to the surface of the photosensitive member and the surface of the intermediate transfer member and maintaining the static friction coefficient μs of both at an appropriate value.
Here, since the lubricant applying device to the photosensitive member and the lubricant applying device to the intermediate transfer belt used as the intermediate transfer member have the same configuration, the configuration of the lubricant applying device to the intermediate transfer belt will be described below. To do.

FIG. 4 is a partially enlarged view of the vicinity of the lubricant application device in the present embodiment, and is a partially enlarged detail of the periphery of the lubricant application device as the lubricant application means for applying the lubricant to the intermediate transfer belt 2. .
The lubricant application device 100 is provided in an intermediate transfer belt cleaning unit, and includes a solid lubricant 60 and a brush roller 50 as a brush-like member for applying the solid lubricant 60 to the intermediate transfer belt 2. I have. The solid lubricant 60 is obtained by dissolving a lubricant additive mainly composed of zinc stearate and then cooling and solidifying the lubricant, and is formed into a bar shape. The solid lubricant is held by the lubricant holding member, and the solid lubricant 60 is pressed against the brush roller 50 via the lubricant holding member by the pressure spring 61 attached to the intermediate transfer belt cleaning unit housing.
The brush roller 50 is provided in contact with the intermediate transfer belt 2, and by the rotation of the brush roller 50, the solid lubricant 60 is scraped to the brush roller 50 side, and the lubricant adhered to the brush roller is separated from the intermediate transfer belt 2. Adheres to the surface of the intermediate transfer belt 2 from the contact portion. As for the rotation direction of the brush roller 50, it does not matter with respect to the present invention whether the brush roller 50 is rotated in the same direction or the reverse direction with respect to the intermediate transfer belt 2.

  As the solid lubricant, a dry solid hydrophobic lubricant can be used. Besides zinc stearate, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, Those having a stearic acid group such as copper stearate, strontium stearate, calcium stearate, cadmium stearate and magnesium stearate can be used. Also, the same fatty acid groups such as zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, palmitic acid, zinc cobalt palmitate, copper palmitate, palmitic acid Magnesium, aluminum palmitate, or calcium palmitate may be used. In addition, fatty acids such as lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate and cadmium ricolinolenate, metal salts of fatty acids, and the like can also be used. Further, waxes such as candelilla wax, carnauba wax, rice wax, wax, ooba oil, beeswax, and lanolin can be used.

Next, features of the lubricant application device 100 according to the present embodiment will be described.
In FIG. 4, blade members 103 and 104 that contact the intermediate transfer belt 2 on the upstream side and the downstream side, respectively, in the moving direction of the intermediate transfer belt 2 across the position where the lubricant is applied to the intermediate transfer belt 2 by the brush roller 50 are shown. One of the blade members, that is, the blade member 103 arranged on the upstream side in the moving direction of the intermediate transfer belt 2 is a cleaning member that removes foreign matters such as toner and paper dust remaining on the surface of the intermediate transfer belt 2. A blade member 104 used as a cleaning blade 103 as a means and disposed downstream in the movement direction with respect to the lubricant application position is a lubricant uniformizing blade 104 used as a lubricant uniformizing means on the surface of the intermediate transfer belt. It is said that.
In the configuration shown in FIG. 4, the lubricant uniformizing blade 104 has a function of leveling the lubricant applied to the surface of the intermediate transfer belt 2, so that the intermediate transfer belt 2 is different from the cleaning blade 103. Thus, a contact state in the trailing direction that can follow the moving direction of the intermediate transfer member 2 is set.

Of the brush roller 50 and the blade, the lubricant uniformizing blade 104 located on the downstream side in the moving direction of the intermediate transfer belt 2 with respect to the lubricant application position is one of the back pressure applying members of the intermediate transfer belt 2. The tension roller 2E is disposed so as to face the outer peripheral surface, and stabilizes the contact state between the brush roller 50, the lubricant uniformizing blade 104, and the intermediate transfer belt 2. The cleaning blade 103 is provided to face the tension roller 2F provided at a position different from the tension roller 2E to which the brush roller 50 and the lubricant uniformizing blade 104 face each other. In this embodiment, the cleaning blade 103 is brought into contact with the surface of the intermediate transfer belt from the counter direction, but the combination of the counter direction and the trailing direction is not limited to this. The cleaning blade 103 and the lubricant uniformizing blade 104 are both made of rubber that can be bent or elastically deformed following the movement of the intermediate transfer belt 2.
In the above configuration, the residual toner remaining on the surface of the intermediate transfer belt after the toner image carried on the surface is secondarily transferred to the transfer paper is first removed by the cleaning blade 103. As a result, the brush roller 50 comes into contact with the surface of the intermediate transfer belt that has become clean, and the lubricant 60 is applied. When the applied lubricant passes through the contact position of the lubricant uniformizing blade 104 on the downstream side in the moving direction of the surface of the intermediate transfer belt, the surface of the lubricant is smoothed and uniformly spread, and the lubricant having a uniform thickness is obtained. It becomes the layer of.
Since the present embodiment is configured as described above, the toner and paper dust remaining on the surface of the intermediate transfer belt 2 after the secondary transfer are removed by the cleaning device 10. At this time, in the lubricant application device 100, the lubricant is applied to the intermediate transfer belt 2 cleaned by the cleaning blade 103 positioned upstream in the moving direction of the intermediate transfer belt 2, and the applied lubricant is used as the lubricant. A uniform thickness can be obtained by the uniformizing blade 104, and the uniform layer is formed in the entire width direction of the intermediate transfer belt 2.

  Thereby, both of the problems occurring in the case of the post-application cleaning method in which the intermediate transfer belt 2 is cleaned only after the lubricant application, which is one of the application methods described above, can be eliminated. As a result, the application amount of the lubricant is biased, the static friction coefficient on the surface of the intermediate transfer belt 2 is biased, and a uniform lubricant layer cannot be formed on the surface of the intermediate transfer belt 2 depending on the application type after cleaning. It is possible to prevent the occurrence of abnormal images such as insect bite, image blur, and blur, and to maintain the application function of the brush roller 50 for a long period of time. Further, since elastically deformable rubber is used for the lubricant uniformizing blade 104, even when the intermediate transfer belt 2 on the side where the lubricant uniformizing blade 104 abuts is driven, load can be absorbed by elastic deformation. The surface of the intermediate transfer belt is not damaged.

  By the way, in the lubricant application device 100 according to the present embodiment, as described above, when dealing with the mainstream of the small diameter, particle size distribution and spheroidization (true sphere) of the toner used, Measures are taken to make it difficult to ensure and maintain the cleaning property on the surface of the carrier. In other words, depending on the conditions of the toner used, the deterioration of the cleaning property causes chipping or abrasion of the cleaning blade, and local streaks on the surface of the image carrier. Conventionally, in order to solve such problems, the contact pressure of the blade has been increased, but with this method, when the concentration of local shearing force occurs on the cleaning blade, the edge at the blade tip will fly. There was a possibility that the durability to the water would be lowered.

  In this embodiment, both the blade members 103 and 104 provided on the upstream side and the downstream side in the moving direction of the intermediate transfer belt 2 across the lubricant application position in the lubricant application device 100 are first and second cleaned. It is used as a member.

  FIG. 5 is a diagram illustrating the above-described configuration. In FIG. 5, the blade 103 on the upstream side in the movement direction of the intermediate transfer belt 2 with the lubricant application position as a slope is used as the first cleaning blade, and on the downstream side in the movement direction. The blade 104 positioned is used as a second cleaning blade, and among these blades, the second cleaning blade 104 also serves as a lubricant uniformizing blade.

  Similarly to the first cleaning blade 103, the second cleaning blade 104 is set in a counter-type contact state with respect to the intermediate transfer belt 2, and has a backup function for the first cleaning blade 103. Note that the contact state of the second cleaning blade 104 is not limited to the above-described counter method, and may be a trailing method. In any method, not only the cleaning function but also the lubricant is uniformized. In the case of having a function together, it is a condition that the function can be achieved.

  In this configuration, the second cleaning blade 104 having a backup function with respect to the first cleaning blade 103 has not only a simple cleaning function but also a function of uniformly leveling the lubricant. Multifunctionalization can be achieved without increasing the number of parts without providing a member having a backup function.

  On the other hand, when both the first and second cleaning blades 103 and 104 are brought into contact with the intermediate transfer belt 2 by the counter method, the ability to scrape off foreign matters such as toner and paper dust is superior to the trailing method. Therefore, in order to take advantage of this advantage, when the both blades are brought into contact with each other by the counter method, the inclination angle of the leading edge with respect to the intermediate transfer belt 2 is defined.

That is, FIG. 6 is a diagram for explaining a configuration relating to the tilt angle (θ). In FIG. 6, the first and second cleaning blades 103 and 104 are intermediate transfer belts used as image carriers. 6 or the moving direction of the photosensitive member, the configuration shown in FIG. 6, the inclination angle (θ) of the leading edge is defined with respect to the tangent line (1) of the intermediate transfer belt 2 and the tension roller 2E around which the belt is wound. Now, assuming that the inclination angle of the leading edge of the first cleaning blade 103 is α ° and the inclination angle of the leading edge of the second cleaning blade 104 is β °, the relation of α ≦ β is established. The reason for this setting is as follows.
In general, the larger the inclination angle of the leading edge of the cleaning blade, the more durable it is against the phenomenon that the leading edge is caught following the movement of the image carrier. Therefore, although the toner is often dammed to the first cleaning blade 103, the amount of toner dammed by the leading edge is smaller in the second cleaning blade 104 than in the first cleaning blade 103. For this reason, in the first cleaning blade 103, it is conceivable to increase the range in which the toner is received. However, if the first cleaning blade 103 is increased, the leading edge is likely to be caught by the movement of the image carrier. Therefore, by using the backup function by the second cleaning blade 104, the inclination angle of the leading edge of the first cleaning blur degree 103 is reduced to reduce the deterioration of the cleaning property due to the entrainment. In this embodiment, the inclination angles are set to 80.5 ° on the first cleaning blade 103 side and 82.9 ° on the second cleaning blade 104 side.

  The configuration in which cleaning and leveling of the lubricant are performed by the blade members provided on the upstream side and the downstream side with respect to the lubricant application position described in the above-described embodiment is only for the intermediate transfer belt 2. The present invention can also be applied to a photoreceptor used as an image carrier.

  When cleaning the surface of the intermediate transfer belt 2 using a cleaning member, it is possible to use a cleaning brush in which a bias is applied to a conductive brush having a medium resistance to a low resistance instead of the cleaning blade.

  In addition, the present invention is not limited to the above-described embodiments, and can be applied to all apparatuses using the technical idea of the present invention. The photosensitive member and the intermediate transfer member may be any of a belt shape, a drum shape, and a roller shape.

1 is a schematic diagram illustrating a configuration of an image forming apparatus to which a lubricant application device according to an embodiment of the present invention is applied. It is a figure which shows typically the shape of the toner used for this invention Example. It is a figure which shows typically the shape of the toner used for this invention Example. It is a schematic diagram which shows an example of the lubricant coating device by the Example of this invention. It is a schematic diagram which shows the other example of the lubricant coating device by the Example of this invention. It is a schematic diagram for demonstrating the inclination | tilt angle of the front-end edge of the cleaning blade by this invention Example. It is a schematic diagram which shows an example of the conventional lubricant application format. It is a schematic diagram which shows the other example of the conventional lubricant application type | mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color printer 2 Intermediate transfer belt which is one of image carriers 2E Tension roller 50 Brush roller 60 Solid lubricant 100 Lubricant coating device 103 Cleaning blade 104 Lubricant equalizing blade

Claims (12)

The lubricant can be moved while in contact with the surface of the image carrier that can move in a predetermined direction, and the lubricant is moved to the image carrier in the process of moving in the order of contact with the image carrier after contacting the lubricant. Lubricant coating apparatus comprising a lubricant coating member that can be supplied, and blade members that contact the image carrier on the upstream side and the downstream side in the moving direction of the image carrier across the lubricant coating member, respectively. In
Among the blade members, the blade member located downstream of the lubricant application member in the moving direction of the image carrier is a uniform lubricant that smoothes the lubricant applied to the surface of the image carrier by the lubricant application member. Lubricant coating apparatus, characterized in that it is a control member.   2. The lubricant application device according to claim 1, wherein the blade member is formed of a member that can be bent or elastically deformed in contact with the image carrier.   An image forming apparatus using the lubricant application device according to claim 1.   4. The blade member according to claim 3, wherein the blade member is provided as a first and a second cleaning member on the upstream side and the downstream side of the lubricant application member in the moving direction of the image carrier. The image forming apparatus described.   Of the blade members, a blade member positioned downstream in the moving direction of the image carrier with the lubricant application member interposed therebetween is provided as both the cleaning member and the lubricant uniformizing member. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.   The first and second cleaning members are counter blades opposed to the image carrier in the counter direction, and the first cleaning member in the moving direction of the image carrier at a position of contact with the image carrier. The inclination angle of the leading edge of the cleaning member is α °, and the inclination angle of the leading edge of the second cleaning member with respect to the moving direction of the image carrier at the position of contact with the image carrier is β °. 6. The image forming apparatus according to claim 4, wherein a relationship of α ≦ β is set.   7. The latent image carrier and a transfer body positioned on a side to which an image carried on the latent image carrier is transferred are used as the image carrier. Image forming apparatus.   The toner 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) in the range of 1.0 to 1.40. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.   9. The toner according to claim 3, wherein a toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 190 is used as the toner. Image forming apparatus.   As the toner, a toner material liquid in which a polyester prepolymer having a functional group containing at least 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 3, wherein the toner is an obtained toner.   11. The image forming apparatus according to claim 3, wherein a toner having a substantially spherical shape is used as the toner.   As the toner, Keio is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1> r2> r3), and a ratio (r2 / r1) between the major axis r1 and the minor axis r2 is 0.5. The ratio of thickness r3 to minor axis r2 (r3) / r2) is in the range of 0.7 to 1.0. The image forming apparatus according to any one of the above.

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