JP5435331B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a copying machine and a facsimile machine having a configuration in which a nip forming member that forms a transfer nip in contact with an image carrier is brought into contact with and separated from the image carrier as it is swung about a rocking shaft. The present invention relates to an image forming apparatus such as a printer.

  In this type of image forming apparatus, the nip forming member is brought into contact with and separated from the image carrier for the purpose of suppressing the disturbance of the toner image on the image carrier and improving the workability of the jam paper removing operation. It is like that.

  For example, in the image forming apparatus described in Patent Document 1, toner adhesion to a secondary transfer roller as a nip forming member is suppressed as follows. That is, in the image forming apparatus, yellow (Y), magenta (M), cyan (C), and cyan (C) are transferred from the photosensitive member to the intermediate transfer belt in the course of four rotations of an endless intermediate transfer belt as an image carrier. The black (K) toner images are sequentially superimposed and primarily transferred. As a result, a four-color superimposed toner image is formed on the intermediate transfer belt. Thereafter, the recording paper is fed into the secondary transfer nip formed by the contact between the intermediate transfer belt and the secondary transfer roller as the nip forming member, and the four-color superimposed toner image on the belt is secondarily transferred to the recording paper. To do. Prior to the secondary transfer, when the four-color superimposed toner image is obtained by rotating the belt four times, if the secondary transfer roller is in contact with the intermediate transfer belt, the toner image on the intermediate transfer belt is transferred to the secondary transfer roller. Disturbed by the transfer roller. Therefore, during the primary transfer for superposition, the secondary transfer roller is separated from the intermediate transfer belt, thereby suppressing the disturbance of the toner image on the belt caused by pressing the secondary transfer roller.

  Some image forming apparatuses that do not perform superimposing primary transfer employ a configuration in which a nip forming member such as a transfer roller is brought into contact with or separated from an image carrier such as a photosensitive member or an intermediate transfer belt. This is because when a jam of the recording paper occurs in the vicinity of the transfer nip, the nip forming member is separated from the image carrier so that the jammed paper can be easily removed.

  For the reasons described above, the nip forming member such as the transfer roller is brought into contact with and separated from the image carrier by swinging. However, when a sudden cause such as a jam occurs, a relatively large amount of the nip forming member with respect to the nip forming member Toner may adhere. Therefore, in the image forming apparatus described in Patent Document 1, a secondary transfer cleaning device for cleaning the surface of the secondary transfer roller is provided, and is swung together with the secondary transfer roller. If the capacity of the toner storage portion of the secondary transfer cleaning device is increased, the swinging mechanism and the like are increased in size, which hinders space saving. For this reason, the toner in the toner accommodating portion of the secondary transfer cleaning device is dropped into a toner conveyance tube disposed in the image forming apparatus main body. The toner conveying tube receives the toner removed from the surface of the photosensitive member and the intermediate transfer belt into the tube, and conveys the toner to a waste toner container by driving the conveying member. The toner in the toner container of the secondary transfer cleaning device is dropped onto the toner transport tube, thereby saving space in the toner container.

  However, the secondary transfer cleaning device needs to be swung together with the secondary transfer roller as described above. When the secondary transfer cleaning device is swung, the distance between the secondary transfer cleaning device and the toner transport tube changes accordingly. Nevertheless, in the image forming apparatus described in Patent Document 1, since the toner storage portion of the secondary transfer cleaning device and the toner transport pipe are connected by a non-deformable conduit, the distance cannot be changed. . Therefore, Patent Document 1 describes that the secondary transfer cleaning device is swung together with the secondary transfer roller. However, contrary to this description, the secondary transfer cleaning device and the secondary transfer roller are swung. It has a structure that can not be.

  If a bellows hose or a flexible hose is used as the conduit, the secondary transfer cleaning device can be swung. This is because the bellows hose can be expanded and contracted and the flexible hose can be relaxed by following the change in the distance between the secondary transfer cleaning device and the toner conveying tube.

  However, when the bellows hose is used, the toner lump formed by the toner deposited on the spiral concave portion of the inner wall of the hose is gradually grown, and the hose may be blocked with the toner lump eventually. . In addition, even when a flexible hose is used, there is a possibility that a toner lump is formed by the toner staying at the bending portion of the hose and the hose is blocked.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress the generation of toner lumps in a conduit that guides toner from a removing means that swings together with a nip forming member to a toner conveyance tube. It is an object of the present invention to provide an image forming apparatus.

In order to achieve the above object, an invention according to claim 1 oscillates about an image bearing member for carrying a toner image, image forming means for forming a toner image on the image carrier, and a pivot shaft. A nip forming member that is supported by a swinging support member, contacts and separates from the image bearing member with swinging, and forms a transfer nip by contact with the image bearing member, and a recording member sandwiched between the transfer nips A transfer means for transferring the toner image on the image carrier, a first removal means for removing toner adhering to the surface of the image carrier after passing through the transfer nip, and removal by the first removal means. A toner conveying tube for receiving and conveying at least one of the generated toner and used toner generated by the image forming means to the collected toner container, and being supported by the swinging support member , Toner adhering to the nip forming member An image forming apparatus comprising: a second removing unit to be removed; and a conduit for guiding the toner in the toner container of the second removing unit toward the toner transport pipe below the toner container. A toner relay portion is disposed on the swing axis of the swing support, and one end portion of the toner transport pipe is connected to the toner relay portion, and a lower end portion of the conduit is connected to the toner relay portion. To do.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the toner relay portion is provided with a slide member that slides on a swinging track centering on the swing axis, and a lower end portion of the conduit Is connected to the slide member.
According to a third aspect of the present invention, in the image forming apparatus of the second aspect , the toner image detecting means for detecting the toner image transferred onto the surface of the nip forming member, and a predetermined operation at a predetermined timing. After a toner image for image performance detection is formed on the surface of the image carrier and transferred to the surface of the nip forming member, the toner image for image formation performance detection on the surface is detected by the toner image detection means. Control means for performing image forming condition adjustment processing for adjusting the image forming condition of the image forming means based on the result is provided.
According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect, as the nip forming member, an endless nip forming belt that is endlessly moved while being wound around a plurality of stretching members is used. It is characterized by.
According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the fourth aspect , wherein a plurality of latent image carriers that carry latent images and the latent image carriers individually correspond to the latent images by toners of different colors. A plurality of developing means for developing an image; and a superimposing transfer means for superposing and transferring toners of different colors developed on the surface of the latent image carrier on an intermediate transfer member as the image carrier; individually corresponding to the plurality of latent image carriers, and a plurality of said first removing means for removing the used toner remaining on the latent image bearing member surface after the intermediate transfer process provided for the intermediate transfer member, The first removal means are arranged side by side at different horizontal coordinates, and the toner conveying tube is arranged to receive the toner falling from each of the first removal means. You It is intended.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect , the nip forming belt is brought into contact with and separated from the intermediate transfer member as the swinging support member is swung. Among the latent image carriers, the black latent image carrier is brought into contact with and separated from the latent image carrier, and the recording member is moved into the transfer nip by the contact between the nip forming belt and the black latent image carrier. later, by entering the transfer nip due to contact between the nip forming belt and the intermediate transfer member, directly transferred to a recording member without passing through the intermediate transfer member for black toner image on the latent image bearing member for black It is characterized by doing.
According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, the first removal means for black is connected to a developing means for black instead of being connected to the toner conveying tube. To do.
The invention according to claim 8 is the image forming apparatus according to any one of claims 1 to 7, wherein toner having an average circularity of 0.92 or more is used.
The invention according to claim 9 is the image forming apparatus according to any one of claims 1 to 8, wherein the shape factor SF-1 is in the range of 100 to 180, and the shape factor SF-2 is 100. As described above, the toner having 180 or less is used.
The invention of claim 10 is the image forming apparatus according to any one of claims 1 to 9, wherein the volume average particle diameter is in the range of 3 [μm] to 5 [μm] and the volume. A toner having a value obtained by dividing the average particle diameter by the number average particle diameter in the range of 1.05 to 1.40 is used.
The invention according to an eleventh aspect is the image forming apparatus according to any one of the first to tenth aspects, wherein the toner contains a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release accelerator. A toner obtained by treating the composition by at least one of a crosslinking reaction and an elongation reaction in an aqueous medium is used.

  In these inventions, the nip forming member and the second removing means for removing the toner on the surface of the nip forming member are swung around the swing axis where the toner relay portion is located. The distance between the means and the toner relay portion is constant regardless of the swing position of the second removing means. For this reason, it is possible to use a linear shape that does not expand and contract as the conduit connecting the second removing means and the toner relay portion. Such a conduit does not deposit toner in a helical recess like a bellows hose, or deposits toner in a bent portion like a flexible hose. Generation of toner lumps can be suppressed.

1 is a schematic configuration diagram showing a copier according to an embodiment. FIG. 3 is an enlarged configuration diagram illustrating the periphery of a secondary transfer nip in the copier. FIG. 2 is a schematic configuration diagram illustrating a toner recovery mechanism in the copier. FIG. 5 is a schematic diagram showing various tubes in the toner recovery mechanism. FIG. 3 is an explanatory diagram for explaining the swing of a secondary transfer unit and the swing of a reverse retransmission unit of the copier. FIG. 3 is a perspective view showing a toner relay unit and a conduit in the toner recovery mechanism. FIG. 6 is a schematic diagram illustrating a maximum diameter MXLNG and a planar area AREA of a projected image with respect to a two-dimensional plane of toner particles. FIG. 4 is a schematic diagram for explaining a peripheral length PERI and a flat area AREA of a projected image with respect to a two-dimensional plane of toner particles. (A), (b), (c) is a figure which shows the shape of a toner typically, respectively.

Hereinafter, an embodiment of an electrophotographic color copying machine (hereinafter simply referred to as a copying machine) will be described as an image forming apparatus to which the present invention is applied.
FIG. 1 is a schematic configuration diagram illustrating a copying machine according to an embodiment. In FIG. 1, the copying machine includes a printer unit and a scanner 16 mounted and fixed on the printer unit. The scanner 16 reads an image of a document by a known technique.

  The printer unit includes four image forming units 12Y, 12C, 12M, and 12K for forming yellow, cyan, magenta, and black (hereinafter referred to as Y, C, M, and K) toner images. Further, the belt is stretched in a posture extending in a horizontal direction by a driving roller 17, a driven roller 18, tension rollers 19 and 20, and three primary transfer rollers 21Y, 21C, 21M, and 21K disposed inside the belt loop. An intermediate transfer belt 6 is also provided. The intermediate transfer belt 6 as an image carrier is moved endlessly in the counterclockwise direction in the figure by the rotational driving of the driving roller 17.

  The four image forming units 12 </ b> Y, 12 </ b> C, 12 </ b> M, and 12 </ b> K are arranged along the stretched surface of the intermediate transfer belt 6. The drum-shaped photoreceptors 1Y, 1C, 1M, 1K, charging devices 2Y, 2C, 1M, 1K, developing devices 3Y, 3C, 3M, and 3K, and drum cleaning devices 4Y, 4C, 4M, and 4K are provided. In a state where the unit is held by a common holding body as a unit, they are integrally attached to and detached from the casing of the printer unit. The charging devices 2Y, 2C, 2M, and 2K uniformly charge the peripheral surfaces of the photoreceptors 1Y, 1C, 1M, and 1K, which are rotationally driven by a driving unit (not shown), in the dark with a polarity opposite to that of the toner It is what you want to do.

  An optical writing unit 5 is disposed below the image forming units 12Y, 12C, 12M, and 12K. Color image information sent from the scanner 16 or an external personal computer (not shown) is decomposed into Y, C, M, and K information by an image processing unit (not shown) and then processed in the printer unit. The optical writing unit 5 drives Y, C, M, and K light sources (not shown) by a known technique based on Y, C, M, and K color-separated image information, and outputs Y, C, M, and K light sources. Write light for K is generated. Then, the peripheral surfaces of the photoreceptors 1Y, 1C, 1M, and 1K that are uniformly charged by the charging devices 2Y, 2C, 2M, and 2K are scanned with Y, C, M, and K writing light. Thereby, electrostatic latent images for Y, C, M, and K are formed on the peripheral surfaces of the photoreceptors 1Y, 1C, 1M, and 1K. Examples of the light source for the writing light include laser diodes and LEDs.

  The electrostatic latent images formed on the peripheral surfaces of the photoreceptors 1Y, 1C, 1M, and 1K are developed by developing devices 3Y, 3C, 3M, and 3K that employ a well-known two-component development system, and are then developed into Y, C, M, and K. A K toner image is obtained. The developing devices 3Y, 3C, 3M, and 3K are equipped with Y, C, M, and K toner density sensors (not shown) that detect the toner density of the Y, C, M, and K developers contained therein, respectively. ing. When the Y, C, M, K toner density sensor detects a decrease in the toner density of the Y, C, M, K developer, the Y, C, M, K toner replenishing device 33Y, C, M, K is predetermined. By operating for a time, the replenishing Y, C, M, K toner in the Y, C, M, K toner container is replenished into the developing devices 3Y, C, M, K. As a result, the toner concentrations of the Y, C, M, and K developers in the developing devices 3Y, 3C, 3M, and 3K are maintained within a predetermined range. As the developing devices 3Y, 3C, 3M, and 3K, those using a known one-component developing device may be used.

  Of the four photoconductors, the Y, C, and M photoconductors 1Y, C, and M are in contact with the intermediate transfer belt 6 to form a primary transfer nip for Y, C, and M. In addition, primary transfer rollers 21Y, 21C, and 21M that press the belt toward the Y, C, and M photoconductors 1Y, 1C, and 1M are disposed inside the loop of the intermediate transfer belt 6. A primary transfer bias is applied to each of the primary transfer rollers 21Y, 21C, and 21M, whereby a transfer electric field is formed in the primary transfer nip for Y, C, and M. The Y, C, and M toner images formed on the peripheral surfaces of the photoreceptors 1Y, 1C, and 1M are transferred to the intermediate transfer belt 6 at the primary transfer nip for Y, C, and M by the action of the transfer electric field and nip pressure. Are transferred onto the surface. As a result, a three-color superimposed toner image is formed on the front surface of the intermediate transfer belt 6.

  A secondary transfer unit 26 is disposed on the right side of the intermediate transfer belt 6 in the drawing. The secondary transfer unit 26 includes an endless paper conveyance belt 8 and a secondary transfer cleaning device 15. The paper conveying belt 8 is stretched in a vertically long posture by a drive roller 25, a tension roller 27, a secondary transfer roller 28, and a primary transfer roller 21K for K, and is rotated clockwise in the figure by the rotational drive of the drive roller 25. It can be moved endlessly in the direction. A secondary transfer nip is formed by bringing a portion around the secondary transfer roller 28 into contact with a driving portion of the intermediate transfer belt 6 with respect to the driving roller 17. In addition, a primary transfer nip for K is formed by bringing a portion around the primary transfer roller 21K for K itself into contact with the photosensitive member 1K for K.

  A first paper feed cassette 22 and a second paper feed cassette 23 are disposed below the housing of the printer unit so as to overlap in the vertical direction. These paper feed cassettes send out the recording paper P accommodated therein to the paper transport path. The fed recording paper P abuts against a registration roller pair 24 disposed in a paper conveyance path extending in the vertical direction in the printer unit and the skew is corrected, and then sandwiched between the rollers of the registration roller pair 24. . Then, it is sent out further upward at a predetermined timing by the registration roller pair 24.

  The recording paper P delivered from the registration roller pair 24 sequentially passes through the K primary transfer nip and secondary transfer nip formed in the paper conveyance path. When passing through the primary transfer nip for K, the K toner image on the peripheral surface of the photoreceptor 1K is primary transferred. Further, after passing through the secondary transfer nip, the three-color superimposed toner image on the intermediate transfer belt 6 is secondarily transferred collectively onto the K toner image. Thereby, a full-color image is formed on the surface of the recording paper P.

  The transfer residual toner adhering to the surface of the photoreceptors 1Y, 1C, 1M, 1K after passing through the primary transfer nips for Y, C, M, and K is transferred by the drum cleaning devices 4Y, 4C, 4M, and 4K. Removed. The drum cleaning devices 4Y, C, M, and K for Y, M, C, and K have been shown to scrape toner with a cleaning blade. However, a fur brush roller, a magnetic brush cleaning method, and the like have been shown. It may be used.

  Above the secondary transfer nip, a fixing device 10 is provided that forms a fixing nip by contact between a heating roller and a pressure roller. The recording paper P that has passed through the secondary transfer nip is sent to the fixing nip in the fixing device 10 and subjected to a fixing process for a full-color image. After this, it approaches the path switching position by a switching claw (not shown). When the switching claw selects the paper discharge path R1 as the path, the recording paper P passes through the paper discharge roller pair 30 and faces down to the paper discharge tray 31 provided on the upper surface of the printer unit housing. Is discharged and stacked. On the other hand, when the switching claw has selected the reversing route R <b> 2 as the route, the recording paper P is sent to the reversing retransmission unit 35. When the reversal retransmission unit 35 receives the recording paper P sent from the switching claw, the reversal retransmission unit 35 switches it back and then transports it in a retransmission path extending from the upper side to the lower side in the vertical direction so as to be turned upside down. The recording sheet P in the state of being fed is sent again to the registration roller pair 24. Then, the fed recording paper P passes through the primary transfer nip and secondary transfer nip for K in order, and after the full color image is transferred to the back side, the full color image is transferred in the fixing device 10. It can be fixed on the back side. Thereafter, the sheet is stacked on the sheet discharge tray 31 via the switching claw and the sheet discharge roller pair 30.

  A first belt cleaning device 7 serving as a first removing unit is in contact with a portion where the intermediate transfer belt 6 is wound around the driven roller 18. Then, the transfer residual toner adhering to the surface of the intermediate transfer belt 6 after passing through the secondary transfer nip is removed. The first belt cleaning device 7 is not limited to the blade cleaning type, and various types can be adopted.

  A second belt cleaning device 15 as a second removing unit is in contact with a portion of the paper transport belt 8 that is wound around the driving roller 25. Then, the transfer residual toner adhering to the surface of the paper conveying belt 8 after passing through the secondary transfer nip is removed. The second belt cleaning device 15 is not limited to the cleaning method using the cleaning blade 9, and various methods can be adopted.

  In the present copying machine, in the monochrome mode for forming a monochrome image, the optical writing unit 5 optically scans the K photoconductor 1K based on monochrome image data sent from the scanner 16 or an external personal computer. The K electrostatic latent image formed thereby is developed into a K toner image by the K developing device 3K. The K toner image is directly transferred onto the recording paper P at the primary transfer nip for K and then fixed onto the recording paper P by the fixing device 10.

  In the monochrome mode, as shown in FIG. 2, the secondary transfer roller 28 in the loop of the paper conveyance belt 8 is moved away from the intermediate transfer belt 6 to separate the paper conveyance belt 8 from the intermediate transfer belt 6. . Then, by forming monochrome images with the Y, C, and M image forming units 12Y, 12C, and 12M and the intermediate transfer belt 6 stopped, it is possible to avoid exhaustion due to such unnecessary driving. Yes.

  Further, in the monochrome mode, the recording paper P can be quickly fed from the registration roller pair 34 to the primary transfer nip for K without waiting for the completion of the primary transfer of superposition, thereby realizing high-speed printing. Can do.

  The side of the paper conveying belt 8 having a shorter circumference than the intermediate transfer belt 6 contacts and separates, and the intermediate transfer belt 6 can be stationary (not linked to the paper conveying belt 8), so there is no fluctuation in tension of the intermediate transfer belt 6. The intermediate transfer belt 6 having a large number of color matching can be configured to be in contact with or separated from the paper transport belt 8, but in this case, the positional accuracy for color matching may be lowered with time. On the other hand, since the intermediate transfer belt 6 may be kept in contact with the Y, C, M photoconductors 1Y, 1C, 1M, the positioning accuracy between the rollers of the intermediate transfer belt 6 is increased, and there is a margin for the belt shift. The degree can be improved. Furthermore, since the belt running is stabilized, it is possible to improve the margin with respect to color misregistration during full color.

  Conventionally, a configuration is also known in which the intermediate transfer belt 6 is separated from the Y, C, and M photoconductors 1Y, 1C, and 1M when the monochrome mode is executed. In this method, since the intermediate transfer belt 6 needs to be displaced, the problem of fluctuations in belt tension is unavoidable.

  The drive roller 17 that supports the intermediate transfer belt 6 may be displaced by means (not shown) so that the intermediate transfer belt 6 is brought into contact with and separated from the paper transport belt 8. In this case, since the conveying posture of the recording paper P is not changed, the behavior of the recording paper P between the paper conveying belt 8 and the fixing device 10 can be stabilized. For this reason, it is possible to suppress the occurrence of wrinkles and image distortion on the recording paper P after being discharged from the fixing device 10.

  To the Y, C, and M photoconductors 1Y, 1C, and 1M, toner of a color different from its own color may reversely transfer from the intermediate transfer belt 6. For example, the Y toner image that has already been primarily transferred onto the surface of the intermediate transfer belt 6 may come into contact with the C photoconductor 1 </ b> C, and the Y toner may reversely transfer. Also, the Y toner image or C toner image that has already been primarily transferred onto the surface of the intermediate transfer belt 6 may come into contact with the M photoconductor 1M, and the Y toner or C toner may reversely transfer. . In addition, C toner and M toner that have not been completely removed from the belt surface even by the belt cleaning device 7 may be reversely transferred to the Y photoreceptor 1Y. Since such reverse transfer occurs, the toner collected in the drum cleaning devices 4Y, 4C, 4M is in a mixed state and is difficult to recycle. Further, the toner collected in the belt cleaning device 7 from the intermediate transfer belt 6 is also in a mixed color state and is difficult to recycle. Therefore, the toner collected by the drum cleaning devices 4Y, 4C, and M and the toner collected by the belt cleaning device 7 are collected in a waste toner container.

  FIG. 3 is a schematic configuration diagram showing a toner recovery mechanism in the copying machine. A toner conveying tube 102 extending in the horizontal direction (left-right direction in the figure) is provided in the housing of the printer unit. A large-capacity waste toner container 101 is disposed below the toner transport tube 102 in the housing, and is connected to the toner transport tube 102 by a waste conduit 103 extending in the vertical direction.

  Above the toner conveyance tube 102 in the vertical direction, the belt cleaning device 7 and the drum cleaning devices 4Y, C, and M for Y, C, and M are arranged in the horizontal direction. The belt cleaning device 7 conveys the toner scraped off from the intermediate transfer belt 6 toward the front end portion in the direction perpendicular to the drawing surface of the housing of the belt cleaning device 7 by an internal discharge screw. The upper end of the belt waste toner conduit 104 is connected to the front end. The lower end of the belt waste toner conduit 104 is connected to the toner conveyance tube 102. The collected toner in the belt cleaning device 7 is dropped into the belt waste toner conduit 104 and gravity falls into the toner conveying tube 102.

  The drum cleaning devices 4Y, 4C, and 4M for Y, C, and M are orthogonal to the drawing sheet surface of the housing of the cleaning device by the toner discharged from the peripheral surfaces of the photoreceptors 1Y, 1C, and 1M, with the internal discharge screw. Transport toward the front end of the direction. The upper end of Y, C, M drum waste toner conduits 105Y, C, M is connected to the front end. The lower ends of the Y, C, and M drum waste toner conduits 105Y, C, and M are connected to the toner transport tube 102. The collected toner in the drum cleaning devices 4Y, 4C, 4M, and 4K is dropped into the drum waste toner conduits 105Y, C, M, and K, and dropped into the toner conveying tube 102 by gravity.

  In the toner conveying tube 102, as shown in FIG. 4, the internal screw member 102a is rotationally driven to convey the collected toner toward the waste conduit 103. The waste conduit 103 is located on the right side of the entire area in the longitudinal direction of the toner conveying tube 102 and connected to the belt waste toner conduit 104 in the drawing, and the drum waste toner conduit 105Y for Y, M, and C. , M, and C are connected to a region on the left side in the drawing. For this reason, in the toner conveyance pipe 102, it is necessary to convey the toner from the left side to the right side in the drawing on the left side of the disposal conduit 103, whereas on the right side in the drawing, compared with the disposal conduit 103. The toner needs to be conveyed in the opposite direction. By reversing the inclination of the screw blades of the screw member 102 a between the left side region and the right side region of the disposal conduit 103, such reverse conveyance is possible.

  Since the K photoconductor 1K is disposed in non-contact with the intermediate transfer belt 6, Y, C, and M toners are supplied to the K photoconductor 1K via the intermediate transfer belt 6. It won't stick. Therefore, the toner collected by the K drum cleaning device 4K is only K toner having no color mixture. Therefore, in this copying machine, the collected toner is not sent to the waste toner container 101 by the K drum cleaning device 4K but is sent to the K developing device 3K for recycling.

  In the present copying machine, the entire apparatus is controlled by a control unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. This control unit performs image forming condition adjustment processing for adjusting image forming conditions such as the optical writing unit 5 and the image forming units (12Y, M, C, K) of the respective colors at a predetermined time interval. It is to be implemented at the timing. In this image forming condition adjustment process, a process control process and a positional deviation correction process which will be described later are performed. In these processes, a gradation pattern image for image density detection and a patch pattern image composed of a plurality of toner images for color misregistration detection are formed on the surface of the paper conveying belt 8 as a nip forming member.

  More specifically, in the process control process in the image forming condition adjustment process, the intermediate transfer belt 6 is formed so that the gradation pattern images for image density detection are not overlapped with each other for Y, C, M, and the paper. Transfer to the conveyor belt 8. Further, the gradation pattern image (K) for image density detection formed on the K photoconductor 1K is directly transferred to the paper conveying belt 8 by the K image forming unit. These gradation pattern images are composed of a plurality of Y, M, C, and K reference toner images each having a predetermined pixel pattern. A plurality of Y, M, C, and K reference toner images are formed so as to have different toner adhesion amounts (image densities).

  For example, taking the K gradation pattern image SK as an example, this is composed of a plurality of K reference toner images, Y reference toner images SK1, SK2, SK3,... Has been. These K reference toner images are formed so as to be arranged at predetermined intervals in the traveling direction of the paper conveying belt 8. Then, the toner adhesion amount per unit area with respect to the K reference toner image is detected by a reflection type photosensor (not shown) as an image detection unit (not shown) facing the paper transport belt 8 at a predetermined distance. This detection result is sent to the control unit. Similarly, the toner adhesion amount with respect to each Y, C, M reference toner image in the Y, C, M gradation pattern image formed on the paper transport belt 8 is detected.

  Based on the output value from the reflection type photosensor stored in the RAM and the data table stored in the ROM 202, the control unit converts each output value into a toner adhesion amount per unit area, and attaches the toner. It is stored in the RAM 203 as quantity data. Then, a combination of the sensor output value stored in the RAM and the toner adhesion amount data is selected for each color in a region where the relationship between the potential data and the toner adhesion amount data (development characteristics) is a straight line. Then, smoothing processing of these data is performed. Then, a linear approximation of the development characteristics is performed for each color by applying the least square method to the smoothed potential data and toner adhesion amount data. Further, after obtaining a linear equation y = ax + b of the developing characteristics of each developing device for each color, the image forming conditions for each color are adjusted based on the slope a in this linear equation. Examples of the method for adjusting the image forming conditions include a method for adjusting the uniform charging potential of the photosensitive member and the developing bias as described in JP-A-9-211191. When the two-component development method is adopted, the control target value of the toner concentration of the two-component developer may be adjusted.

  In the misregistration correction process in the image forming condition adjustment process, a misregistration detection patch pattern is formed in the vicinity of both ends of the paper transport belt 8 in the width direction. Each patch pattern formed near both ends is composed of four Y, M, C, and K reference toner images Sy, Sm, Sc, and Sk that are arranged at predetermined intervals in the belt traveling direction. It is formed to line up in the belt width direction. The control unit adjusts the optical writing start timing and the optical system for each photoconductor based on the timing when the Y, M, C, and K reference toner images Sy, Sm, Sc, and Sk are detected by the reflective photosensor. Thus, the relative displacement of the toner images of each color is suppressed.

  A plurality of toner images are formed on the paper conveying belt 8 by the image forming condition adjusting process as described above. These are detected by the secondary transfer cleaning device 15 after being detected by the reflective photosensor. It is designed to be removed from the surface.

  FIG. 5 is an explanatory diagram for explaining the swing of the secondary transfer unit 26 and the swing of the reverse retransmission unit 35. When a recording paper jam occurs in the paper conveyance path in the housing, as shown in the figure, the reverse retransmission unit 35 is rotated a little in the counterclockwise direction in the figure around the swing shaft 201. Then, the secondary transfer unit 26 in the housing is exposed. In this state, when the secondary transfer unit 26 is rotated a little in the counterclockwise direction in the drawing in the drawing, the paper transport belt 8 is separated from the intermediate transfer belt 6 and the K photoconductor 1K. As a result, the paper conveyance path is greatly exposed. Thus, the jammed paper can be easily removed by largely exposing the paper conveyance path.

  The secondary transfer unit 26 supports the paper transport belt 8 and the secondary transfer cleaning device 15 on a swing support that swings about a swing shaft, and swings them integrally. As described above, in the image forming condition adjustment process, a large amount of toner images are formed on the surface of the paper transport belt 8, so that a large amount of toner is collected in the secondary transfer cleaning device 15. If the toner storage portion of the secondary transfer cleaning device 15 has a large capacity so that they can be received sufficiently, the reverse retransmission device 35 is moved to the right side of the illustrated arrangement position to receive the toner storage device. Since it is necessary to secure a space, the apparatus is enlarged.

  Therefore, in this copying machine, the toner in the toner container of the secondary transfer cleaning device 15 is guided to the toner transport tube 102 and transported to the waste toner container 101. Thus, even if a large amount of toner is collected from the surface of the paper conveying belt 8 without increasing the size of the toner storage portion of the secondary transfer cleaning 15 or the copying machine housing, the toner is frequently discarded to the user. It won't force you.

Next, a characteristic configuration of the copying machine will be described.
In FIG. 5, the secondary transfer unit 26 swings around the swing axis at a position above the swing axis in the vertical direction. That is, the secondary transfer unit 26 is positioned above the swing axis in the vertical direction regardless of the swing position.

  A toner relay 106 is fixed to the front end surface of the swing shaft that supports the secondary transfer unit 26 so as to be swingable in a direction orthogonal to the drawing surface. The right end of the toner conveying tube 102 in the housing is connected to the left side of the toner relay device 106 in the drawing. In addition, an upper end portion of a conduit 107 for dropping toner is connected to the toner storage portion of the secondary transfer cleaning device 15, and a lower end portion of the conduit 107 is connected to a slide engagement portion of the toner relay device 106. ing.

  FIG. 6 is a perspective view showing the toner relay 106 and the conduit 107. When the secondary transfer unit (26) (not shown) swings, the conduit 107 swings around the toner relay 106 in a posture in which the lower end portion thereof is always directed toward the toner relay 106. In the toner relay device 106, a slide portion 106b that slides on a swinging track centering on a swinging axis line of a secondary transfer unit (not shown) is engaged with the reservoir main body 106a. And the lower end part of the conduit | pipe 107 is connected to the slide part 106b. When the conduit 107 swings following the swing of the secondary transfer unit, the slide portion 106b slides following the swing, thereby allowing the conduit 107 to swing.

  In this configuration, the paper transfer belt 8 and the secondary transfer cleaning device 15 are swung around the swing axis where the toner relay 106 is located, so the secondary transfer cleaning device 15 and the toner relay are swung. The distance to 106 is constant regardless of the swing position. For this reason, as the conduit 107 connecting the secondary transfer cleaning device 15 and the toner relay device 106, a linear shape that does not expand and contract as shown in the figure can be used. Such a conduit 107 does not deposit toner in a spiral recess like a bellows hose or deposits toner in a bent portion unlike a flexible hose. The generation of toner lump can be suppressed.

Next, toner used in the copying machine according to the embodiment will be described.
The toner is composed of at least a binder resin and a colorant, and a lubricant for reducing friction is externally added to the toner surface. In addition, a charge control agent for controlling the chargeability of the toner and releasability to the fixing device. It may contain an external additive that contains a release agent or the like that improves fluidity and imparts fluidity.

  The binder resin is an ester resin, a vinyl resin, an amide resin, an epoxy resin, a silicone resin, or the like, and a vinyl resin is particularly preferable. Specifically, styrene such as polystyrene, poly P-chlorostyrene, polyvinyltoluene, and the like Homopolymer of the substituted product, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl acrylate copolymer, styrene-butyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-butadiene copolymer, styrene-meta Use methyl acrylate-butyl acrylate copolymer, etc. Rukoto can.

  As the colorant, all 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, bengara, red lead, lead vermilion, cadmium red, cadmium mercurial red, antimony vermilion, permanent red 4R, para red, phise red, parachlor ortho nitroaniline red, risor fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Per Nent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean blue, alkali blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone Violet, chrome green, zinc green, pigment green B, naphthol green B, green Ngorudo, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The content of the colorant is usually 1 to 15%, preferably 3 to 10%, based on the toner.

  As the charge control agent, for example, a salicylic acid compound, a nigrosine dye, a quaternary ammonium salt compound, an alkylpyridinium compound, or the like can be used. The content is usually from 0.1 to 5%, preferably from 1 to 3%, based on the toner.

  As the release agent, for example, polyolefin wax such as low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight polyethylene-polypropylene copolymer, ester wax such as fatty acid lower alcohol ester, fatty acid higher alcohol ester, fatty acid polyhydric alcohol ester, An amide wax or the like can be used. The content is usually 0.5 to 10%, preferably 1 to 5%, based on the toner.

  A toner having a circularity of 0.92 or more is used. The degree of circularity can be obtained by an expression “(peripheral length of circle having the same area as the projected particle area / perimeter length of projected particle image) × 100%”. The closer the toner is to a true sphere, the closer the circularity is to 100 [%]. This degree of circularity can be further increased by thermally or mechanically spheroidizing the toner produced by dry grinding. Thermally, for example, the spheronization treatment can be performed by spraying toner base particles together with a hot air stream on an atomizer or the like. In addition, a spheroidizing treatment can be performed by mechanically charging the mixture into a mixer such as a ball mill together with a mixed medium such as glass having a low specific gravity and stirring. However, in the thermal spheronization treatment, toner base particles that are aggregated and have a large particle size or fine particles are generated in the mechanical spheronization treatment, and thus a second classification step is required. In addition, in a toner manufactured in an aqueous solvent, the shape can be controlled by applying strong stirring in the process of removing the solvent.

  When toner having a circularity of 0.92 or more is used, it becomes difficult to scrape and remove the toner by contact with a cleaning member such as a cleaning blade. This is because the toner rolls well on the surface of the photoreceptor or belt to be removed. If the cleaning blade is brought into contact with the object to be removed with a considerable pressure, the removability can be improved to some extent, but the smooth surface movement of the photoconductor and the belt is hindered to easily generate a banding image.

  In view of this, it is preferable to provide an application means for applying a lubricant such as zinc stearate to a subject to be removed such as a photoreceptor or a belt. In this way, the frictional resistance between the toner and the surface to be removed can be reduced by the lubricant, the cleaning performance by the cleaning member can be improved, the transferability can be improved, and the residual toner can be reduced. Become. Furthermore, it is possible to make it difficult to generate a banding image even if the cleaning member is brought into contact with the removal target with a somewhat strong pressure.

  A fluidity imparting agent may be added to the toner. Examples of the fluidity-imparting agent include fine particles of metal oxides such as silica, titania, alumina, magnesia, zirconia, ferrite, and magnetite, and metal oxides obtained by treating these fine particles with a silane coupling agent, titanate coupling agent, or zircoaluminate. Fine particles. Silica and titania hydrophobized with a coupling agent are preferred. Since the primary particle diameter of silica is small, the effect of imparting fluidity is large. Further, titania can control the toner charge amount. It is more preferable to add these in combination.

  The amount of the lubricant added externally to the toner is preferably adjusted in the range of 0.1 to 2.0 [%]. When the addition amount of the lubricant is less than 0.1 [%], the supply amount of the lubricant to the photoreceptor is insufficient, and it becomes difficult to reduce the friction coefficient of the photoreceptor. On the other hand, when the addition amount exceeds 2.0 [%], the amount of lubricant transferred from the photosensitive member to the charging member such as the charging roller becomes excessive, and an abnormal image is likely to be caused.

  As the volume average particle diameter Dv of the toner decreases, the fine line reproducibility improves. For this reason, toner of 8 [μm] or less is used as the toner (specified in the instruction manual). However, since the developing property and the cleaning property are lowered when the particle size is reduced, those having a particle size of 3 [μm] or more are used. It is not preferable that the volume average particle diameter Dv is less than 3 μm [less than] because the amount of reversely charged toner increases and an abnormal image such as ground fog is formed. In this copying machine, a toner having a volume average particle size of 3 to 5 μm is used in consideration of the above trade-off.

  The particle size distribution represented by the ratio (Dv / Dn) of the volume average particle size Dv to the number average particle size Dn is preferably in the range of 1.05 to 1.40. By sharpening the particle size distribution, the toner charge amount distribution can be made uniform. When Dv / Dn exceeds 1.40, the toner charge amount distribution is wide and the amount of the reversely charged toner T1 increases, making it difficult to obtain a high-quality image. If Dv / Dn is less than 1.05, it is difficult to produce and it is not practical. Therefore, in this copying machine, toner having a particle size distribution in the range of 1.05 to 1.40 is used. The particle size of the toner is measured as follows. That is, the aperture of the measurement hole corresponding to the particle size of the toner to be measured is set in a Coulter counter multisizer (manufactured by Coulter), and the average particle size of 50,000 toner particles is measured.

Further, it is preferable to use 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 180. FIG. 7 is a schematic diagram for explaining the maximum diameter MXLNG and the flat area AREA of the projected image with respect to the two-dimensional plane of the toner particles. The shape factor SF-1 indicates the ratio of the roundness of the toner shape, and is obtained by the formula “SF-1 = {(MXNLNG) ² / AREA} × (100π) / 4”. This is a value obtained by dividing the square of the maximum diameter MXLNG of the projected image with respect to the two-dimensional plane of the toner particles by the plane area AREA and multiplying by 100π / 4. 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.

FIG. 8 is a schematic diagram for explaining the peripheral length PERI and the planar area AREA of the projected image with respect to the two-dimensional plane of the toner particles. The shape factor SF-2 indicates the ratio of the unevenness of the shape of the toner particles, and is obtained by the formula “SF-2 = {(PERI) ² / AREA} × 100 / (4π)”. A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner particles on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4. 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 randomly selecting 100 toner particles from the toner and taking a photograph with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.). Was introduced into an image analysis apparatus (LUSEX 3: manufactured by Nireco), and the shape factor of each toner particle was analyzed, and the average value thereof was used as the final shape factor. 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 transfer rate is also increased. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

  The shape of the toner is substantially spherical and can be expressed by the following shape rule. That is, as shown in FIGS. 9A, 9B, and 9C, the substantially spherical toner has a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3). Stipulate. The toner has a major axis / minor axis ratio (r2 / r1) (see FIG. 9B) of 0.5 to 1.0 and a thickness / minor axis ratio (r3 / r2) (FIG. 9). 9 (c)) is preferably in the range of 0.7 to 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 shape of the toner can be controlled by the manufacturing method. For example, the toner by the dry pulverization method has an irregular shape in which the toner surface is uneven and the toner shape is not constant. Even this dry pulverized toner can be made into a nearly spherical toner by applying mechanical or thermal treatment. In many cases, a toner produced by forming droplets by a suspension polymerization method or an emulsion polymerization method has a smooth surface and a nearly spherical shape. Moreover, it can be made into an ellipse by stirring in the middle of the reaction in a solvent and applying a shearing force.

  Further, as a substantially spherical toner, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent is crosslinked and / or in the presence of resin fine particles in an aqueous medium. Or it is preferable to use what makes an extension reaction.

Hereinafter, the constituent material of the toner and a suitable manufacturing method will be described.
Polyester, which is one of the constituent materials, is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.

Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.
Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1. The polycondensation reaction between 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 preferred range of the weight average molecular weight is 10,000 to 400,000, desirably 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.

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

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B) to be reacted with the polyester prepolymer (A), divalent amine compounds (B1), trivalent or higher polyvalent amine compounds (B2), amino alcohols (B3), amino mercaptans (B4), amino acids (B5), and those obtained by blocking the amino groups 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 B1 to B5 blocked amino groups (B6) 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 the amines (B) is equivalent to the equivalent ratio [NCO] / [NH _x of the isocyanate group [NCO] in the polyester prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (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] / [NH _x ] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance deteriorates.

  The urea-modified polyester may contain a urethane bond as well as 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 the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator may 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 to 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 the temperature is less than 45 [° C.], the heat resistance of the toner deteriorates, and if it exceeds 65 [° 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 heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners. The substances described above can be used for the colorant, charge control agent, release agent, external additive and the like.

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
1) Purification of toner material liquid A colorant, unmodified polyester, polyester prepolymer having an isocyanate group, and a release agent are dispersed in an organic solvent to prepare a toner material liquid. 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) Emulsification of toner material liquid 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 salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  By using a surfactant having a fluoroalkyl group, the effect can be increased 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).

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

  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 Corporation) , SGP (manufactured by Sokensha), Technopolymer SB (manufactured by Sekisui Plastics Co., Ltd.), SGP-3G (manufactured by Sokensha), Micropearl (manufactured by Sekisui Fine Chemical), and the like. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above-described resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymeric 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 nonyl phenyl ether, polyoxyethylene, lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, poly Polyoxyethylenes such as oxyethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, in order to make the particle size of the dispersion 2 to 20 [μm], a high-speed shearing method is preferable. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 [rpm], preferably 5000 to 20000 [rpm]. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 [° C.] (under pressure), preferably 40 to 98 [° C.].

3) Reaction with polymer At the same time as the preparation of the emulsion, 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) Obtaining toner base particles 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) Final adjustment A charge control agent is injected into the obtained toner base particles, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. When preparing a developer by adding external additives and lubricants, these may be added simultaneously or separately and mixed. For mixing external additives and the like, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, and the like. It is preferable to prevent the embedding of the external additive and the formation of a thin film on the toner surface of the lubricant by changing the mixing conditions such as the rotation speed, rolling speed, time, and temperature. 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 spherical shape and the spindle shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. Can do.

  The toner produced by the above method can be mixed with a magnetic carrier and used as a two-component developer. In this case, the toner concentration of the carrier and the toner in the developer is preferably 1 to 10 parts by weight of the toner with respect to 100 parts by weight of the carrier. The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier or a non-magnetic toner.

1Y, C, M, K: Photoconductor for Y, C, M, K 3Y, C, M, K: Developing device (developing means) for Y, C, M, K
5: Optical writing unit (part of image forming means)
6: Intermediate transfer belt (image carrier)
7: Belt cleaning device (first removing means)
8: Paper transport belt (nip forming member)
12Y, C, M: Image forming unit for Y, C, M (part of image forming means)
15: Secondary transfer cleaning device (second removing means)
21Y, C, M: primary transfer roller for Y, C, M, K (superposition transfer means)
28: Secondary transfer roller (transfer means)
102: Toner transport pipe 106: Toner relay (toner relay section)
106b: slide member 107: conduit

JP 2006-235290 A

Claims (11)

An image carrier that carries a toner image, an image forming unit that forms a toner image on the image carrier, and a rocking support that rocks about a rocking shaft. A nip forming member that contacts and separates from the carrier and forms a transfer nip by contact with the image carrier; and a transfer unit that transfers a toner image on the image carrier to a recording member sandwiched by the transfer nip. , A first removing unit for removing toner adhering to the surface of the image carrier after passing through the transfer nip, a toner removed by the first removing unit, and a used toner generated by the image forming unit A toner conveying tube for receiving at least one of them and conveying it to the collected toner container, and a first member for removing the toner adhering to the nip forming member while being supported by the swing support. 2 removing means and the second removing means The toner in over accommodating portion in the image forming apparatus and a conduit for directing toward the toner transport pipe is located below the said toner accommodating portion,
A toner relay portion is disposed on the swing axis of the swing support, and one end portion of the toner transport tube is connected to the toner relay portion, and a lower end portion of the conduit is connected. An image forming apparatus. The image forming apparatus according to claim 1.
An image forming apparatus, wherein a slide member that slides on a swinging track centering on the swinging axis is provided in the toner relay portion, and a lower end portion of the conduit is connected to the slide member. The image forming apparatus according to claim 2 .
Toner image detecting means for detecting a toner image transferred on the surface of the nip forming member;
After a predetermined toner image for detecting the image forming performance is formed on the surface of the image carrier and transferred to the surface of the nip forming member, the toner for detecting the image forming performance on the surface is transferred. An image forming apparatus comprising: a control unit that performs an image forming condition adjusting process for adjusting an image forming condition of the image forming unit based on a result of detecting an image by the toner image detecting unit. The image forming apparatus according to claim 3.
An image forming apparatus using an endless nip forming belt that is endlessly moved while being wound around a plurality of stretching members as the nip forming member. The image forming apparatus according to claim 4 .
A plurality of latent image carriers that carry latent images;
A plurality of developing means corresponding to each of the latent image carriers and developing the latent image with different color toners;
Superposition transfer means for superposing and transferring toners of different colors developed on the surface of the latent image carrier onto the intermediate transfer member as the image carrier;
Individually corresponding to the plurality of latent image carriers, and a plurality of said first removing means for removing the used toner remaining on the latent image bearing member surface after the intermediate transfer process provided for the intermediate transfer member,
These first removing means are arranged side by side at different horizontal coordinates,
An image forming apparatus, wherein the toner conveying pipe is disposed so as to receive the toner falling from each of the first removing means. The image forming apparatus according to claim 5 , wherein
Along with the swing of the swing support, the nip forming belt is brought into contact with and separated from the intermediate transfer member and, among the plurality of latent image carriers, is also brought into contact with and separated from the black latent image carrier. ,
Further, after the recording member enters the transfer nip by the contact between the nip forming belt and the black latent image carrier, the recording member enters the transfer nip by the contact between the nip forming belt and the intermediate transfer member. Te image forming apparatus characterized by directly transferring to the recording member without passing through the intermediate transfer member for black toner image on the latent image bearing member for black. The image forming apparatus according to claim 6.
An image forming apparatus, wherein the first removing unit for black is connected to a developing unit for black instead of connecting to the toner conveying tube. The image forming apparatus according to claim 1,
An image forming apparatus using a toner having an average circularity of 0.92 or more. The image forming apparatus according to any one of claims 1 to 8,
An image forming apparatus using 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 180. The image forming apparatus according to any one of claims 1 to 9,
The volume average particle size is in the range of 3 [μm] to 5 [μm], and the value obtained by dividing the volume average particle size by the number average particle size is in the range of 1.05 to 1.40. An image forming apparatus using a toner. The image forming apparatus according to claim 1,
A toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release accelerator is treated in an aqueous medium by at least one of a crosslinking reaction and an extension reaction. An image forming apparatus using the toner obtained as described above.

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