JP2008102353A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device which avoids toner filming and an image forming apparatus in which even when a low-melting toner is used, image degradation occurs hardly. <P>SOLUTION: The cleaning device removes residual toner from a surface of a member to be cleaned after a toner image held on the surface is fixed on a recording medium, wherein the toner contains ≥5 wt.% of a crystalline resin and has a loss modulus at 40°C of 2×10<SP>8</SP>to 7×10<SP>8</SP>Pa. The cleaning device has a removal section where a potential difference is produced between the section and the member to be cleaned and electric force by the potential difference is allowed to act on the toner to remove the toner from the surface of the member to be cleaned, and a storage section where the toner removed by the removal section is at least temporarily stored. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning device that removes toner from the surface of an object to be cleaned, and an image forming apparatus that forms an image composed of a fixed toner image on a recording medium by transferring and fixing the toner image on the recording medium.

  2. Description of the Related Art Conventionally, image forming apparatuses such as printers and copiers have been widely used, and technologies relating to various elements constituting such image forming apparatuses have also been widely used. Among image forming apparatuses that employ an electrophotographic method, an electrostatic latent image is formed on an image carrier such as an image carrier drum, and toner is attached to the electrostatic latent image. Thus, a developed toner image is formed. The toner image thus formed on the image carrier is directly transferred onto the recording medium, or transferred onto the recording medium via a transfer belt or the like, and after transfer, the toner image is added by the fixing device. The toner image is fixed on the recording medium by pressure and heating.

In recent years, in the field of image forming apparatuses, there has been a strong demand for reduction in power consumption during fixing processing from the viewpoint of ecology, and an image forming apparatus that employs a low melting point toner that melts at a low temperature and is fixed on a recording medium. (For example, refer to Patent Documents 1 to 4). In the image forming apparatus employing such a low melting point toner, in addition to reducing the power consumption, there is an advantage that the image forming speed is increased because the heating time is reduced.
JP-A-6-208319 JP 2006-235028 A JP 2006-257574 A Japanese Unexamined Patent Publication No. 2006-091081

  Although the low melting point toner has excellent characteristics that enable reduction of power consumption and high speed image formation, image formation using the low melting point toner has some image quality problems.

  One of them is the occurrence of uneven gloss in the image. The temperature of the recording medium to which the toner image is transferred often differs somewhat depending on the location on the recording medium. For a toner that melts at a low temperature, such as a low melting point toner, the temperature difference causes the recording medium. There is a difference in the degree of melting of the toner, and a difference in glossiness tends to occur. Such gloss unevenness is particularly noticeable in color images and is recognized as an obvious image quality defect. In particular, in the case of color double-sided output, the recording medium when the toner image is output on the first surface of the recording medium, reflecting the fact that the temperature of the recording medium differs greatly before and after the heat treatment at the time of fixing. There is a large temperature difference between this temperature and the temperature of the recording medium when the toner image is output to the second surface of the recording medium, and the occurrence of uneven gloss becomes a problem.

  Another problem is an image quality defect due to the occurrence of filming of toner on the image carrier. Many low-melting toners have a core-shell structure in which a binder resin (core) containing a low-melting resin is covered with a surface layer (shell) whose main component is an amorphous polymer resin. In the fixing process of the unfixed toner image, the surface layer of the low-melting toner is destroyed and the binder resin comes out of the surface layer and is fixed on the recording medium. At this time, since the surface layer needs to be destroyed at a low temperature, the low melting point toner has a property that it has a low strength and is easily crushed. On the image carrier after the transfer of the toner image, the toner remaining without being transferred adheres. An electrophotographic image forming apparatus includes a transfer member that transfers a toner image while being pressed against an image carrier, and low-melting-point toner remaining on the image carrier repeatedly receives pressure from the transfer member. In many cases, the toner image is crushed and toner filming occurs on the image carrier. Many image forming apparatuses are equipped with a cleaning blade that presses against the image carrier and scrapes off the residual toner as a cleaning means for removing residual toner. Ming often occurs. Such toner filming changes the properties and characteristics of the surface of the image carrier and causes image quality defects in the formed image.

  Due to the above-described problems of image quality degradation due to uneven gloss and toner filming, further contrivance is required for forming a good image while taking advantage of the excellent characteristics of the low melting point toner.

In view of the above circumstances, an object of the present invention is to provide a cleaning device that avoids toner filming, and an image forming apparatus in which image quality is unlikely to deteriorate even when low-melting toner is used.

In order to achieve the above object, the cleaning device of the present invention comprises:
In a cleaning device that removes residual toner from the surface of a cleaning object that is fixed on a recording medium and that holds a toner image on the surface,
The toner contains 5% by weight or more of a crystalline resin and has a loss elastic modulus at 40 ° C. of 2 × 10 ⁸ Pa or more and 7 × 10 ⁸ Pa or less,
A removing unit that removes the toner from the surface of the object to be cleaned by causing a potential difference with the object to be cleaned and applying an electric force due to the potential difference to the toner;
And a storage unit that stores at least temporarily the toner removed by the removal unit.

The temperature of the recording medium is often slightly different depending on the location on the recording medium, and such a temperature difference may cause a difference in the degree of melting of the toner on the recording medium. The toner as the loss modulus of the toner is small is to melt at lower temperatures, if the loss elastic modulus at 40 ° C. is 7 × 10 8 ^[Pa] is greater than the temperature of the toner at low recording medium portion Melting may be delayed, and gloss unevenness occurs on the image after fixing. Further, when the loss elastic modulus at 40 ° C. is smaller than 2 × 10 ⁸ [Pa], the toner melts too much in the recording medium portion where the temperature is high, so that gloss unevenness is also generated on the fixed image. To do. Therefore, by adopting a toner whose loss elastic modulus at 40 ° C. falls within the range of 2 × 10 ⁸ [Pa] to 7 × 10 ⁸ [Pa], it is possible to avoid uneven gloss. The toner having such a low elastic modulus has a low strength and is liable to cause toner filming when pressed on the surface of the object to be cleaned.

In the cleaning device of the present invention, the residual toner is removed by electrostatic force. In such a cleaning method using an electrostatic force, if the toner is easily charged, it is easily removed, and this cleaning method is effective. In general, a crystalline resin has a property that charge can be easily injected, and a toner containing such a crystalline resin has a stable chargeability. The residual toner to be removed by the cleaning device of the present invention is a toner having a crystalline resin ratio of 5% or more by weight and a considerably high ratio of the crystalline resin, and the chargeability of the toner is extremely stable. Yes. For this reason, in the cleaning device of the present invention, sufficient residual toner removal is performed by the above-described cleaning method using electrostatic force, and there is no need to exert a strong pressure contact force on the object to be cleaned. . Therefore, toner filming hardly occurs even with a low-strength toner whose loss elastic modulus at 40 ° C. is in the range of 2 × 10 ⁸ [Pa] to 7 × 10 ⁸ [Pa]. Therefore, it is difficult for image quality defects to occur in the image after fixing. In addition, since the damage to the object to be cleaned can be reduced, the life of the object to be cleaned can be extended. As an example of the crystalline resin as described above, for example, a crystalline polyester resin can be given.

  In addition, a mode in which “the removal unit is a brush that has hairs that generate a potential difference with the object to be cleaned and that makes the electrical force act by bringing the hairs into contact with the toner” is also a preferable mode. is there.

  According to such a form, the residual toner can be easily removed by electrostatic force.

  In addition, a form in which “the removal portion generates a potential difference of 100 V or more and 400 V or less between the object to be cleaned” is also a preferable form.

  When the voltage applied to the residual toner is too large, the residual toner is charged to a polarity opposite to the charging polarity of the residual toner, and the cleaning property is deteriorated. On the other hand, if the applied voltage is too small, removal of the residual toner is insufficient. In the cleaning device of the present invention, by applying a voltage of 100 [V] or more and 400 [V] or less to the residual toner, it is sufficient to prevent charging to a polarity opposite to the charging polarity of the residual toner. Cleanability is demonstrated.

  Further, a form in which “the toner has a shape factor of 100 or more and 130 or less” is also a preferable form.

  In general, a toner having a shape close to a sphere is more suitable for a cleaning method that uses electrostatic force because the toner surface has a uniform charge distribution and the polarity of the toner tends to be stable. In the cleaning device of the present invention, toner having a nearly spherical shape in the region of 100 to 130 is targeted for removal, and high cleaning performance is realized.

In order to achieve the above object, an image forming apparatus of the present invention comprises:
An image holding member is formed, a toner image is formed on the image holding member, and the toner image is transferred from the image holding member and fixed on the recording medium, whereby an image composed of the toner image is formed on the recording medium. In the image forming apparatus to be formed,
The toner contains 5% by weight or more of a crystalline resin and has a loss elastic modulus at 40 ° C. of 2 × 10 ⁸ Pa or more and 7 × 10 ⁸ Pa or less,
A removing part that removes the toner from the surface of the image carrier by causing a potential difference between the image carrier and an electric force caused by the potential difference to act on the toner, and a toner removed by the removing part It is characterized by having a cleaning device having a storage part for storing at least temporarily.

  Since the image forming apparatus of the present invention includes the above-described cleaning device, both the occurrence of uneven gloss and the avoidance of toner filming are realized, and good image formation in which image quality is unlikely to deteriorate can be achieved. .

  According to the present invention, even when a low-melting toner is used, the image quality is unlikely to deteriorate.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a full-color image forming apparatus corresponding to an embodiment of the image forming apparatus of the present invention.

  An image forming apparatus 1 shown in FIG. 1 includes an image carrier 10 and an intermediate transfer belt 2. The image carrier 10 is a laminated image carrier for electrophotography, and rotates in the direction of arrow A in the figure at the time of image formation. The intermediate transfer belt 2 is an endless belt member stretched around support rolls 60a, 60b, 60c, and 60d, and circulates and moves in the direction of arrow B in the figure following the image carrier 10 during image formation. The intermediate transfer belt 2 includes an elastic belt base material and a protective layer that covers the surface of the belt base material and contains a conductive agent. A primary transfer roll 40a is disposed at a position facing the image carrier 10 with the intermediate transfer belt 2 interposed therebetween, and a secondary transfer roll 40b is provided below (lower side in the figure). It has been. Bias voltages are applied to the primary transfer roll 40a and the secondary transfer roll 40b from the primary transfer bias voltage application unit 41a and the secondary transfer bias voltage application unit 41b, respectively, at the time of image formation.

  Around the image carrier 10, a developing rotary 50, a charger 20, an exposure device 32, and a cleaning device 100 are disposed. The charger 20 is a contact type charger that charges the image carrier 10 while being in contact with the image carrier 10. In the developing rotary 50, developing devices 51 to 54 containing developers each having colored toners of black (BK), yellow (Y), magenta (M) and cyan (C) are arranged along the circumferential direction. The rotary type composite developing device can be switched by the rotation of the developing rotary 50 so as to switch the developing device that performs development in the vicinity of the image carrier 10. Each colored toner has a charging characteristic of charging the negative electrode, and each colored toner is added with external additive particles smaller than toner particles such as a lubricant, a transfer aid, and a cleaning aid. The exposure device 32 serves to irradiate the surface of the image carrier 10 with laser light, and the cleaning device 100 serves to remove the toner remaining on the image carrier 10.

  In addition, the image forming apparatus 1 includes a charging brush 81 that is engaged in cleaning the intermediate transfer belt 2. The charging brush 81 can switch between contact and separation with respect to the intermediate transfer belt 2, and positively charges the toner remaining on the intermediate transfer belt 2 at the time of contact. Control of contact or separation of the charging brush 81 is performed by the CPU 4, and this CPU 4 controls each part of the image forming apparatus such as the primary transfer bias voltage application unit 41 a and the secondary transfer bias voltage application unit 41 b described above. Also controls.

  Next, an image forming operation in the image forming apparatus 1 will be described.

  The image forming apparatus 1 forms an image by receiving input of image information representing one or more images having image signals of four colors of yellow, magenta, cyan, and black. When these image signals are input, the image carrier 10 starts rotating, and the charger 20 uniformly charges the surface of the rotating image carrier 10. Of the input four-color image signals, laser light corresponding to the cyan image signal is first irradiated from the exposure unit 32 toward the image carrier 10, and this irradiation causes a potential on the surface of the image carrier 10. An electrostatic latent image having a potential higher than that of the surroundings is formed. Further, by the rotation of the developing rotary 50, the developing device 54 containing cyan toner comes close to the image carrier 10 and develops the electrostatic latent image with a developer containing cyan toner. When developing the electrostatic latent image, a developing device 54 containing a developer containing cyan toner is applied with a bias voltage by a developing bias applying unit (not shown), and the potential is changed to the electrostatic latent image. The potential is lower than that of the image carrier 10 and higher than that of the image carrier 10. For this reason, the cyan toner in the developing device 54 adheres to the electrostatic latent image after leaving the developing device 54 due to a potential difference between the electrostatic latent image and the developing device 54 containing the cyan toner. Thus, a cyan toner image is formed.

  Next, the formed cyan toner image is primarily transferred from the image carrier 10 to the intermediate transfer belt 2 by the primary transfer roll 40a. During the primary transfer, the primary transfer roll 40a is primary-transferred to the primary transfer roll 40a so that the potential of the primary transfer roll 40a is higher than the potential on the image carrier 10 where the cyan toner image is located. The primary transfer is realized by the bias voltage application section 41a applying a positive bias voltage.

  Residual toner that remains without being primarily transferred is present on the image carrier 10. This residual toner is removed from the image carrier 10 by the cleaning device 100. The removal of residual toner by the cleaning device 100 will be described later.

  After the residual toner is removed by the cleaning device 100, the surface of the image carrier 10 is again uniformly charged by the charger 20, and this time the developing rotary 50 rotates, and this time the developing device containing magenta toner is stored. 53 is close to the image carrier 10 and a magenta toner image is formed in the same manner as the cyan toner image described above. This magenta toner image is formed when the cyan toner image on the intermediate transfer belt 2 passes through the support rolls 60a, 60b, 60c, and 60d after the primary transfer and returns to the position of the primary transfer roll 40a. The timing is adjusted so that the formed magenta toner image is primarily transferred over the cyan toner image. After the magenta toner image is primarily transferred and superimposed on the cyan toner image, the yellow toner image and the black toner image are formed in the same manner and are superimposed on the magenta toner image and the cyan toner image. As a result, a multicolor toner image is formed on the intermediate transfer belt 2 by superimposing cyan, magenta, yellow, and black toner images.

  Subsequently, the multicolor toner image is secondarily transferred onto the sheet fed from the tray 6 by the paper feed roll 61 at a position sandwiched between the secondary transfer roll 40b and the support roll 60c. At the time of the secondary transfer, the secondary transfer roll 40b has a potential that is higher than the potential on the intermediate transfer belt 2 on which the multicolor toner image is positioned, with respect to the secondary transfer roll 40b. The secondary transfer is realized by the application of the bias voltage by the secondary transfer bias voltage application unit 41b.

  The sheet that has undergone the secondary transfer of the multicolor toner image is subjected to heat and pressure by the fixing device 62 that is provided at a position separated in the right direction of the secondary transfer roll 40b in FIG. Fixing processing is performed.

  When an image is formed on only one side of the sheet, the toner image is fixed by the fixing unit 62 and then discharged rightward as indicated by a right arrow in the figure. When image formation is performed on both sides of the sheet, the toner image is fixed on one side of the sheet in the fixing unit 62 and then returned without being discharged and passes between the pair of registration rollers 8 a near the fixing unit 62. It is conveyed in the left direction through a route indicated by a left-pointing arrow. Then, in the figure, the registration roll pair 8b shown on the left side of the secondary transfer roll 40b turns the transport direction to the right and goes again to the secondary transfer roll 40b. Here, during the period from when the sheet is first transferred by the secondary transfer roll 40b to when the sheet reaches the position of the secondary transfer roll 40b again, a new multi-color is formed on the intermediate transfer belt 2 by the method described above. A toner image is formed. Then, when the paper reaches the secondary transfer roll 40b for the second time, the new multicolor toner image is secondarily transferred to the surface opposite to that when the paper is subjected to the secondary transfer for the first time. The The paper after the second secondary transfer is subjected to a toner image fixing process by the fixing device 62 and discharged to the right.

  The above is the description of the image forming operation in the image forming apparatus 1.

Generally, the smaller the loss elastic modulus at 40 ° C., the lower the melting point of the toner, and the toner image is fixed at a lower temperature. In this image forming apparatus 1, in order to realize high fixability at a low temperature, the loss elastic modulus at 40 ° C. is 2 × 10 ⁸ [Pa] or more and 7 × 10 ⁸ [Pa] or less. Is adopted. By adopting such a low-melting-point toner, the image forming apparatus 1 achieves both a reduction in power consumption during the fixing process and a reduction in heating time during the fixing process.

  The low-melting-point toner employed in the image forming apparatus 1 has a core-shell structure in which a binder resin (core) containing a low-melting resin is covered with a surface layer (shell) whose main component is an amorphous polymer resin. I have. In the fixing process of the unfixed toner image, the surface layer of the low-melting toner is destroyed and the binder resin comes out of the surface layer and is fixed on the paper. At this time, since the surface layer needs to be destroyed at a low temperature, such a low-melting-point toner has a property that it has a low strength and is easily crushed. For this reason, if the residual toner remaining on the image carrier 10 and the intermediate transfer belt 2 after transfer is not sufficiently removed, the residual toner is transferred to the primary transfer roll 40a (in the case of the intermediate transfer belt 2, the primary transfer rolls 40a and 2). Both of the next transfer rolls 40b) are repeatedly crushed by pressure, and toner filming is likely to occur. Further, when such a low-melting-point toner is subjected to a strong pressure contact force such as a cleaning blade during cleaning, toner filming is likely to occur on the image carrier 10 or the intermediate transfer belt 2 and remains due to a strong pressure contact force. A cleaning method in which toner is scraped off is not preferable.

  In this image forming apparatus 1, in order to avoid such a toner filming problem, the image forming apparatus 1 employs a low-melting-point toner containing a large amount of a crystalline resin having a property of being easily injected with charge as a toner. As a cleaning method, an electrostatic force is used. For this reason, sufficient cleaning is performed without requiring a strong pressure contact force.

  Hereinafter, a cleaning method using electrostatic force will be described. First, the cleaning of the image carrier 10 will be described.

  The cleaning device 100 is provided with an image carrier roll brush 300 and a cleaning blade 31. The housing 101 surrounds the image carrier brush roller 300 and collects residual toner removed from the image carrier 10. Is provided. In the cleaning device 100, the residual toner is removed mainly by the image carrier roll brush 300, and the cleaning blade 31 is for flattening the surface of the image carrier 10 after the residual toner is removed. For this reason, the contact force between the cleaning blade 31 and the image carrier 10 is not so large, compared to the contact force required when the cleaning blade is used to remove residual toner. The contact force is sufficiently small.

  The image carrier roll brush 300 has hairs (brush fibers) 301 extending radially from a rotation shaft extending in the width direction of the image carrier 10, and the hairs 301 rotate around the rotation shaft. While in contact with the surface of the image carrier 10. Examples of fibers used for the hair 301 include resin fibers such as nylon, acrylic, polyolefin, and polyester, and commercially available products such as Beltron (manufactured by Kanebo), SA-7 (manufactured by Toray Industries, Inc.), and UU nylon (manufactured by Unitika). Goods can be used. Further, the bristles 301 are conductive. Examples of a method for imparting conductivity to the bristles 301 include a method of blending a fiber with a conductive powder or an ionic conductive material, a method of forming a conductive layer inside or outside the fiber, and the like.

  The potential of the hair 301 of the image carrier roll brush 300 is higher than the potential of the image carrier 10 due to the voltage application from the toner recovery voltage application unit 302. The residual toner on the image carrier 10 has a negative polarity. Therefore, when the residual toner comes into contact with the hair 301, the residual toner on the image carrier 10 leaves the image carrier 10 and adheres to the hair 301. The residual toner adhering to the bristles 301 is separated from the bristles 301 and falls into the housing 101 when the rotating bristles 301 collide with a brush member (not shown). In this image forming apparatus 1, a voltage of 100 V or more and 400 V or less is used as a voltage for adhering the residual toner to the hair 301, and this voltage is a very low voltage that is applied to collect the residual toner. It is a small voltage. In the cleaning apparatus according to the present invention, instead of the image carrier roll brush 300, a conductive cylinder to which a voltage is applied is brought close to the image carrier 10 and the residual toner is electrically attached to the surface of the cylinder. Can also be adopted.

  The above is an explanation of the cleaning of the image carrier 10.

  Next, cleaning of the intermediate transfer belt 2 will be described.

  The belt roll brush 81 has bristles (brush fibers) 811 extending radially from a rotating shaft extending in the width direction of the endless intermediate transfer belt 2 and moves in the direction of a double-headed arrow C in the figure. Can do. The bristles 811 may be the same as the bristles 301 of the image carrier roll brush 300 described above. After the secondary transfer is performed and the sheet is discharged, the residual toner having a positive polarity upon application of a bias voltage from the secondary transfer bias voltage application unit 41b on the surface of the intermediate transfer belt 2 and the negative electrode Residual toner remains. When the sheet is discharged, the belt roll brush 81 contacts the intermediate transfer belt 2 under the control of the CPU 4. The potential of the bristles 811 of the belt roll brush 81 is higher than the potential of the intermediate transfer belt 2 by voltage application from the toner charging voltage application unit 82, and remains on the bristles 811 on the intermediate transfer belt 2. When the toner comes into contact, the polarity of the toner is made positive. In this image forming apparatus 1, a voltage of 0.5 kV or more and 3.0 kV or less is adopted as a voltage for aligning the polarity of the toner to the positive polarity, and this voltage is applied to align the polarity of the residual toner. The voltage to be used is a very small voltage. In the image forming apparatus of the present invention, instead of the belt roll brush 81, it is also possible to adopt a system in which the polarity of the residual toner is made uniform by bringing a conductive cylindrical body to which voltage is applied into contact with the residual toner.

  Residual toner charged to the positive polarity receives the above-described positive polarity bias from the primary transfer bias voltage application unit 41a at the position of the primary transfer roll 40a, and then shifts from the intermediate transfer belt 20 to the image carrier 10. To do. When the intermediate transfer belt 2 is cleaned, a toner recovery voltage application unit is set so that the potential of the bristles 301 of the image carrier roll brush 300 is lower than the potential of the image carrier 10 in accordance with an instruction from the CPU 4. A voltage is applied from 302 to the hair 301. Therefore, the positive residual toner transferred to the image carrier 10 adheres to the hair 301 having a potential lower than the potential of the image carrier 10, and in the case 101, similarly to the cleaning of the image carrier 10 described above. To be recovered.

  The above is the description of the cleaning of the intermediate transfer belt 2.

The toner employed in the image forming apparatus 1 is a toner having a crystalline resin ratio of 5% or more by weight percent and a considerably high ratio of the crystalline resin, and has high chargeability. For this reason, in the image forming apparatus 1, sufficient residual toner removal is performed by the above-described cleaning method using electrostatic force, and strong press contact with the image carrier 10 and the intermediate transfer belt 2 is performed. There is no need to exert power. Therefore, even when a low-strength toner having a loss elastic modulus at 40 ° C. of 7 × 10 ⁸ [Pa] or less is used, toner filming hardly occurs and image quality defects due to toner filming are avoided. Further, since the damage to the image carrier 10 and the intermediate transfer belt 2 can be reduced, the life of the image carrier 10 and the intermediate transfer belt 2 can be extended. Further, many crystalline resins have a relatively low melting point as a binder resin for toner, and the image forming apparatus 1 contains a large amount of such a crystalline resin, so that a high cleaning property and a good fixing property are obtained. Both are realized. As an example of the crystalline resin as described above, for example, a crystalline polyester resin can be given.

Further, the loss elastic modulus at 40 ° C. of the low melting point toner employed in the image forming apparatus 1 belongs to a narrow range of 2 × 10 ⁸ [Pa] to 7 × 10 ⁸ [Pa].

The temperature of the paper is often slightly different depending on the location on the paper, and such a temperature difference may cause a difference in the degree of toner melting on the paper. The smaller the loss elastic modulus of the toner, the more the toner melts at a lower temperature. However, when the loss elastic modulus at 40 ° C. is larger than 7 × 10 ⁸ [Pa], the toner melts in the paper portion having a lower temperature. May be delayed, and gloss unevenness occurs on the formed image. Further, when the loss elastic modulus at 40 ° C. is smaller than 2 × 10 ⁸ [Pa], the toner is excessively melted in the high-temperature paper portion, and gloss unevenness is also generated on the formed image.

  Such gloss unevenness is particularly noticeable in color images and is recognized as an obvious image quality defect. In particular, in the case of color double-sided output, the temperature of the paper when the toner image is output on the first side of the paper reflects the fact that the temperature of the paper differs greatly before and after the heat treatment at the time of fixing. The temperature difference between the toner image and the temperature of the paper when the toner image is output on the second surface of the paper is large, and the occurrence of uneven gloss becomes a serious problem.

Therefore, in this image forming apparatus 1, by using a low melting point toner whose loss elastic modulus at 40 ° C. is in the range of 2 × 10 ⁸ [Pa] or more and 7 × 10 ⁸ [Pa] or less, paper is used. In order to prevent the influence of the temperature difference from affecting the image, the occurrence of uneven gloss is avoided.

  In addition, since the image forming apparatus 1 employs toner that is easily charged, the voltage applied by the toner recovery voltage applying unit 302 for recovering the residual toner is a considerably small voltage of 400 [V] or less. In addition, sufficient residual toner removal is performed even though the voltage applied by the toner charging voltage application unit 82 is 3.00 [kV] or less in order to make the polarity of the residual toner uniform. .

  If the voltage applied to the toner remaining on the image carrier after the primary transfer is too large, the residual toner on the image carrier is charged to a polarity opposite to the charged polarity of the residual toner, and the cleaning property Decreases. On the other hand, if the applied voltage is too small, removal of the residual toner is insufficient. In this image forming apparatus 1, by applying a voltage of 100 [V] or more and 400 [V] or less to the residual toner, it is sufficient to prevent charging to a polarity opposite to the charging polarity of the residual toner. Cleanability is demonstrated.

  In addition, when a large voltage is applied to the intermediate transfer belt, there is a problem that the material on the surface of the image carrier or the intermediate transfer belt is oxidized and denatured due to the discharge accompanying the voltage application, and the intermediate transfer belt is worn. Advances. In the image forming apparatus 1, the applied voltage for aligning the residual toner to the positive polarity is set to a small voltage of 3.00 [kV] or less, thereby preventing the intermediate transfer member from being worn. On the other hand, if the applied voltage is too low, removal of residual toner will be insufficient this time. However, in this image forming apparatus 1, sufficient cleaning performance is exhibited by applying a voltage of 0.50 [kV] or more. Is done. Therefore, in this image forming apparatus 1, both high cleaning properties and prevention of wear of the intermediate transfer belt 2 are realized.

  Further, the average value of the shape factor of the low melting point toner belongs to the region of 100 or more and 130 or less, and the toner has a shape close to a sphere.

  In general, a toner having a shape close to a sphere is more suitable for a cleaning method that uses electrostatic force because the toner surface has a uniform charge distribution and the polarity of the toner tends to be stable. Therefore, in this image forming apparatus 1, the cleaning property is improved by adopting a toner having a shape close to a sphere in an area of 100 to 130.

Below, the manufacturing method of the toner employ | adopted with this image forming apparatus 1, and the manufacturing method of the two-component developer which has the toner are demonstrated. Here, as an example, a method for producing a toner having a loss elastic modulus at 40 ° C. of about 4 × 10 ⁸ [Pa], a ratio of crystalline resin in the toner of 5%, and a toner shape factor of about 115 will be described.

-Crystalline resin-
Here, the “crystalline polyester resin” refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning weight measurement (DSC). Here, the “crystallinity” used for the electrostatic charge developing toner is D in the differential scanning calorimetry (DSC).
This means that the SC curve has a clear endothermic peak. Specifically, the heating rate is 10 ° C./min.
It means that an endothermic peak when measured in step 1 occurs and then returns to the baseline of the DSC curve.

Specifically, the crystalline resin is more preferably an aliphatic crystalline polyester resin having an appropriate melting point and an alkyl group having 6 or more carbon atoms. The polyester resin having an alkyl group having 6 or more carbon atoms can be obtained by using a polymerizable monomer having an alkyl group having 6 or more carbon atoms in a polyvalent carboxylic acid or polyhydric alcohol, such as dodecenyl succinic acid. However, the present invention is not limited to this.
Examples of the polyvalent carboxylic acids used for producing the resin used in the present embodiment include:
Terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2
, 6-Naphthalenedicarboxylic acid, aromatic dicarboxylic acid such as diphenic acid, p-oxybenzoic acid, aromatic oxycarboxylic acid such as p- (hydroxyethoxy) benzoic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, adipine Acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acid such as dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, dimer acid, trimer acid, hydrogenated Unsaturated aliphatic and alicyclic dicarboxylic acids such as dimer acid, cyclohexanedicarboxylic acid, cyclohexene dicarboxylic acid, etc., and other polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid, etc. A polyvalent carboxylic acid or the like can be used.

Examples of the polyhydric alcohol used for the production of the resin include aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, aromatic polyhydric alcohols and the like. Aliphatic polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Neopentyl glycol, diethylene glycol, dipropylene glycol,
Lactone polyester polyols obtained by ring-opening polymerization of lactones such as dimethylol heptane, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and ε-caprolactone And triols and tetraols such as trimethylol ethane, trimethylol propane, glycerin, and pentaerythritol.

Alicyclic polyhydric alcohols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, tricyclodecane Examples include diol, tricyclodecane dimethanol, dimer diol, hydrogenated dimer diol and the like.

As aromatic polyhydric alcohols, para-xylene glycol, meta-xylene glycol,
Examples include ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adducts of 1,4-phenylene glycol, bisphenol A, ethylene oxide adducts of bisphenol A, and propylene oxide adducts.

A monofunctional monomer may be introduced into the polyester resin for the purpose of blocking the polar group at the end of the resin and improving the environmental stability of the toner charging characteristics. Monofunctional monomers include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, sulfobenzoic acid monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid Acid, tertiary butylbenzoic acid, naphthalenecarboxylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenylacetic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, octanecarboxylic acid, lauric acid,
Monocarboxylic acids such as stearyl acid and lower alkyl esters thereof, or monoalcohols such as aliphatic alcohols, aromatic alcohols, and alicyclic alcohols can be used.

The method for producing the crystalline resin is not particularly limited and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Produced separately depending on the type of monomer.

The crystalline resin can be produced at a polymerization temperature of 180 to 230 ° C., and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If there is a monomer with poor compatibility in the copolymerization reaction,
It is preferable that the monomer and the acid or alcohol to be polycondensed be condensed and then polycondensed together with the main component.

Catalysts that can be used in the production of crystalline resins include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium A phosphorous acid compound, a phosphoric acid compound, an amine compound, etc., specifically, the following compounds are mentioned.

For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide,
Titanium tetrapropoxide, titanium tetraisoproxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, naphthene Zirconate, Zirconyl carbonate, Zirconyl acetate, Zirconyl stearate, Zirconyl octylate, Germanium oxide, Triphenyl phosphite, Tris (2,4-t-butylphenyl) phosphite, Ethyltriphenylphosphonium bromide, Triethylamine, Triphenylamine And the like. The amount of such a catalyst added is preferably 0.01 to 1.00% by weight based on the total amount of raw materials.

As melting | fusing point of crystalline resin, Preferably it is 50-100 degreeC, More preferably, it is 60-
100 ° C. When the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. When the melting point is higher than 100 ° C., sufficient low-temperature fixing cannot be obtained as compared with the conventional toner. There is a case.

The crystalline resin may show a plurality of melting peaks, but in the present invention,
The maximum peak is taken as the melting point.

Furthermore, for example, DSC-7 manufactured by Perkin Elmer can be used for measurement of the melting point of the resin of the present invention. The temperature correction of the detection part of this apparatus can be similarly performed by measuring the glass transition point of the resin using the melting points of indium and zinc.

The crystalline resin used in the toner of the present embodiment has a weight average molecular weight (Mw) of 8,000 to 35, as measured by molecular weight measurement using a gel permeation chromatography (GPC) method in which tetrahydrofuran (THF) is soluble. 000, preferably 10,000 to 25,
000. When the weight average molecular weight is less than 8,000, the compatibility with the amorphous resin or the release agent proceeds, and plasticity may occur. On the other hand, if it exceeds 35,000, the viscosity at the time of melting the toner increases, and the fixability and image glossiness may be impaired. Here, the molecular weight of the resin is THF
Soluble materials were Tosoh GPC / HLC-9120, Tosoh column “TSKgel Sup
erHM-M "(15 cm), molecular weight was calculated using a molecular weight calibration curve measured with a THF solvent and prepared with a monodisperse polystyrene standard sample. The same measurement was performed for the non-crystalline polyester resin described later.

The toner of the present embodiment preferably has a melting point (mp) measured in accordance with ASTM D3418-8 of the crystalline resin of 50 to 100 ° C. When the melting point is less than 50 ° C., the thermal stability of the toner is lowered, and when it exceeds 100 ° C., the image glossiness at the time of toner fixing is lowered.

The acid value of crystalline resin (mg number of KOH required to neutralize 1 g of resin) is 5 to 50 mg KO.
Control to H / g. When the acid value is less than 5 mgKOH / g, the crystalline resin particles form aggregates, which makes it difficult to form a structure with the release agent, and the crystalline resin particles exist independently in the toner. Or may grow large and be exposed on the surface of the toner,
It is not preferable from the viewpoint of chargeability. Further, when the acid value exceeds 50 mgKOH / g, it may be difficult to encapsulate the toner.
-Amorphous polyester resin-
The amorphous polyester resin is obtained by polycondensation of the above-described polyvalent carboxylic acids and polyhydric alcohols using the above catalyst.

The amorphous resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, put a catalyst, blended in a reaction vessel equipped with a thermometer, stirrer, flow-down condenser,
Heat at 150-250 ° C in the presence of an inert gas (nitrogen gas, etc.) to continuously remove by-product low-molecular compounds out of the reaction system, and stop the reaction when a predetermined acid value is reached. It can be produced by cooling and obtaining the desired reactant.

The glass transition temperature of the non-crystalline polyester resin used in this embodiment is ASTM.
When calculated according to D3418-8, it is essential that the temperature is 50 ° C. or higher.
It is preferably 5 ° C. or higher, more preferably 60 ° C. or higher and lower than 65 ° C. When the glass transition temperature is less than 50 ° C., there is a tendency to aggregate during handling or storage, which may cause a problem in storage stability. On the other hand, when the temperature is 65 ° C. or higher, fixability may be deteriorated.

Moreover, it is preferable that the softening point of the amorphous resin used for this Embodiment is the range of 60-90 degreeC. In the toner in which the softening temperature of the resin is suppressed to less than 60 ° C., the toner tends to aggregate during handling or storage, and the fluidity may be greatly deteriorated particularly during long-time storage. When the softening point exceeds 90 ° C., the fixability may be hindered. Further, since it is necessary to heat the fixing roll to a high temperature, the material of the fixing roll and the material of the base material to be copied are limited.

The amorphous polyester resin used in the toner of the present invention is tetrahydrofuran (THF).
The weight average molecular weight (Mw) is 20,000 to 50,000, preferably 25,000 to 50,000, as determined by gel permeation chromatography (GPC) method of soluble matter.
50,000. When the weight average molecular weight is less than 25,000, not only the heat storage property of the toner is lowered, but also the strength of the fixed image is lowered. On the other hand, if it exceeds 50,000, the fixing property is deteriorated and the image gloss is also lowered.

The acid value of the amorphous polyester resin is preferably 10 to 50 mgKOH / g. The acid value is 1
If it is less than 0 mgKOH / g, the particle size growth of the aggregates during the production of the toner becomes faster, which may cause a problem that the particle size distribution of the resulting toner is expanded. The acid value is 50 m.
If it exceeds gKOH / g, the difference between the acid values of the crystalline resin and the release agent increases, so that only the aggregation with the crystalline resin and the release agent may proceed, and the fixability changes between the toner particles. There is a problem that it will. The acid value of the non-crystalline polyester resin can be adjusted by controlling the carboxyl group at the end of the polyester by the blending ratio and reaction rate of the raw polyhydric carboxylic acid and polyhydric alcohol. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

In the toner of the present embodiment, the weight ratio of the crystalline resin to the amorphous resin is 5/95 to 40/6.
If the ratio of the amorphous resin is less than 60%, good fixing characteristics can be obtained, but the phase separation structure in the fixed image becomes non-uniform, and the strength of the fixed image, particularly the scratch strength, is reduced. May cause problems such as being easy to stick. On the other hand, when it exceeds 95%, sharp melting property derived from a crystalline resin may not be obtained, and plasticity may occur, and toner blocking resistance and image storage stability are maintained while ensuring good low-temperature fixability. May not be possible.

The preparation of the crystalline resin and the amorphous resin particle dispersion can be prepared by adjusting the acid value of the resin or emulsifying and dispersing using an ionic surfactant or the like.

In addition, in the case of resins prepared by other methods, if the resin is soluble in an oily solvent with relatively low solubility in water, the resin is dissolved in those solvents to dissolve the ionic surfactant or polymer electrolyte in water. At the same time, the particles are dispersed in water by a disperser such as a homogenizer, and then heated or decompressed to evaporate the solvent, whereby a resin particle dispersion can be prepared. Alternatively, a resin particle dispersion may be prepared by adding a surfactant to the resin and emulsifying and dispersing in water with a disperser such as a homogenizer or by a phase inversion emulsification method.

The particle diameter of the resin particle dispersion thus obtained can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).
-Release agent-
Specific examples of the release agent as the release agent used in the present embodiment include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point by heating; oleic acid amide, erucic acid amide, Fatty acid amides such as ricinoleic acid amide and stearic acid amide; carnauba wax, rice wax, candelilla wax,
Plant waxes such as tree wax and jojoba oil; animal waxes such as beeswax; mineral and petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, stearyl stearate, behenyl behenate, etc. Waxes of higher fatty acids and higher alcohols; ester waxes of higher fatty acids such as butyl stearate, propyl oleate, glyceryl monostearate, glyceryl distearate, pentaerythritol tetrabehenate and unit or polyhydric lower alcohols Higher fatty acids such as diethylene glycol monostearate, dipropylene glycol distearate, distearic acid diglyceride, tetrastearic acid triglyceride and many polyhydric alcohols Ester waxes consisting of a body; sorbitan higher fatty acid ester waxes such as sorbitan monostearate; and the like cholesterol higher fatty acid ester waxes such as cholesteryl stearate. In this Embodiment, these mold release agents may be used individually by 1 type, and may use 2 or more types together. Also,
In the present embodiment, those having a melting point of 40 ° C. to 120 ° C. are used, but in order to meet the recent demand for low temperature fixability as energy saving measures, in particular, 50 ° C. to 100 ° C.
The thing of 50 degreeC is preferable, More preferably, the thing of 50-80 degreeC is used.

The addition amount of these release agents is preferably in the range of 0.5 to 30% by weight, more preferably in the range of 1 to 20% by weight, and further preferably in the range of 5 to 15 with respect to the total amount of toner.
It is in the range of wt%. When the addition amount is less than 0.5% by weight, there is no effect of adding a release agent, and 30
If the weight percentage is exceeded, the chargeability is likely to be affected, the toner is easily destroyed inside the developing device, the release agent is spent on the carrier, and the charge is likely to be lowered. There is a case.

The volume average particle size of the wax particles in the release agent dispersion is preferably in the range of 0.1 to 0.5 μm, particularly preferably 0.1 to 0.3 μm. When the volume average particle size exceeds 0.5 μm, the toner surface is easily exposed, the powder fluidity of the toner is deteriorated, and filming on the image holding member and the developing member is facilitated. In addition, there is a problem that the release agent particles are not included in the coalescing step and are dropped in the coalescing step. In particular, in the case of obtaining a color toner, if the release agent particles are large, the OHP permeability is lowered due to irregular reflection, and the color reproducibility is also lowered. In addition, the said volume average particle diameter can be measured using the laser diffraction type particle size distribution measuring instrument etc. which were mentioned above, for example. When the volume average particle size is 0.1 μm or less, it is not preferable because sufficient releasability cannot be imparted to the toner.

The dispersion medium in the release agent dispersion is preferably an aqueous medium, and water, pure water, or ion exchange water is used. A surfactant is used as the dispersant. Preparation of the wax dispersion used in the toner of the present invention is, for example, a known dispersion such as a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a high pressure type dispersing machine such as a nanomizer, a microfluidizer, an optimizer, or a gorin. Any method and conditions may be used as long as the method can satisfy the particle size and content as described.
-Colorant-
The colorant is usually present in an effective amount in the toner, for example from about 1 to about 15% by weight of the toner, desirably from about 3 to about 10% by weight. The colorant used in the production method of the present invention is not particularly limited, and a known colorant can be used and can be appropriately selected according to the purpose. One type of pigment may be used alone, or two or more types of pigments of the same type may be mixed and used. Two or more different types of pigments may be mixed and used. Specifically, as the colorant, for example,
Carbon blacks such as furnace black, channel black, acetylene black and thermal black; inorganic pigments such as bengara, aniline black, bitumen, titanium oxide, magnetic powder; fast yellow, monoazo yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine (3B, 6B, etc.), azo pigments such as para-brown; phthalocyanine pigments such as copper phthalocyanine and metal-free phthalocyanine; condensed polycyclic pigments such as flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red and dioxazine violet; Etc.

Also, Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange,
Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red,
Various pigments such as rhodamine B lake, lake red C, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate, para brown, acridine, xanthene, Azo, benzoquinone, azine, anthraquinone, dioxazine, thiazine, azomethine, indigo, thioindigo, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazole, xanthene And various dyes; and the like. You may mix black pigments, such as carbon black, and dye to such an extent that transparency is not reduced to these colorants. Moreover, a disperse dye, an oil-soluble dye, etc. are mentioned.

The dispersion medium for dispersing the colorant is preferably an aqueous medium, and water, pure water, or ion exchange water is used. A surfactant is used as the dispersant. Preparation of the colorant dispersion used in the toner of the present invention is known in the art, for example, media-type dispersers such as ball mills, sand mills, and attritors, and high-pressure dispersers such as nanomizers, microfluidizers, optimizers, and gorin. Any method and conditions may be used as long as the particle size and content as described can be satisfied using a dispersion method.
<Other ingredients>
Other components that can be used in the electrostatic charge developing toner of the present invention are not particularly limited,
It can be suitably selected according to the purpose, and examples thereof include various known additives such as inorganic particles, organic particles, charge control agents, and release agents.

The inorganic particles are generally used for the purpose of improving toner fluidity. Examples of the inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride. , Bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. Among these, silica particles are preferable, and silica particles that have been hydrophobized are particularly preferable.

The average primary particle diameter (number average particle diameter) of the inorganic particles is preferably in the range of 1 to 1000 nm, and the addition amount (external addition) is 0.01 to 20 parts by weight with respect to 100 parts by weight of the toner. The range of is preferable.

Organic particles are generally used for the purpose of improving cleaning properties, transfer properties, and sometimes charging properties. Examples of the organic particles include particles such as polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and polystyrene-acrylic copolymer.

The charge control agent is generally used for the purpose of improving the chargeability. Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts.
<Toner characteristics>
The toner of the present embodiment has a volume average particle diameter of preferably 1 to 12 μm, more preferably 3 to 9 μm, and more preferably 3 to 8 μm. Further, the number average particle diameter of the toner of the present exemplary embodiment is preferably 1 to 10 μm, and more preferably 2 to 8 μm. If the particle size is too small, the productivity becomes unstable, the chargeability becomes insufficient and the developability may be lowered, and if it is too large, the resolution of the image is lowered.
[Developer]
Next, the electrostatic latent image developing developer (hereinafter also referred to as “developer”) of the present invention will be described.

The developer of the present invention is not particularly limited except that it contains the toner of the present invention, and an appropriate component composition can be taken according to the purpose. The developer of the present invention becomes a one-component developer when the toner is used alone, and becomes a two-component developer when the toner and carrier are used in combination.

The carrier is not particularly limited, and examples thereof include known carriers. For example, known carriers such as resin-coated carriers described in JP-A-62-39879, JP-A-56-11461, etc. Is mentioned.

Specific examples of the carrier include the following resin-coated carriers. Examples of the core particle of the carrier include normal iron powder, ferrite, magnetite molding, and the like, and the volume average particle size is in the range of about 30 to 200 μm.

Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, 2-acrylic acid 2- Α-methylene fatty acid monocarboxylic acids such as ethylhexyl, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; vinyl such as acrylonitrile and methacrylonitrile Nitriles; 2
-Vinylpyridines such as vinylpyridine and 4-vinylpyridine; vinyl methyl ether;
Vinyl ethers such as vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; Olefins such as ethylene and propylene; Vinyl-containing fluorine such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene Monomers; homopolymers such as, or copolymers comprising two or more types of monomers, and silicone resins including methyl silicone, methyl phenyl silicone, and the like,
Examples thereof include polyesters containing bisphenol and glycol, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like. These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by weight and more preferably in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the core particles.

For the production of the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. .

In the developer of the present invention, the mixing ratio of the toner and the carrier is not particularly limited and can be appropriately selected according to the purpose. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following description, “part” means “part by mass” unless otherwise specified.
(Measurement method of loss modulus)
In the present invention, the loss modulus is measured at an angular frequency of 6.28 rad / sec, a strain of 0.1%, and 40 ° C.
The loss elastic modulus was obtained from dynamic viscoelasticity measured by a sinusoidal vibration method, and an ARES measuring device manufactured by Rheometric Scientific was used for measurement of dynamic viscoelasticity. The measurement of dynamic viscoelasticity was carried out by setting the toner molded into a tablet on a parallel plate of 8 mm diameter, setting the normal force to 0, and then applying sine wave vibration at a vibration frequency of 6.28 rad / sec. The measurement started from 30 ° C and continued to 50 ° C. The measurement time interval was 30 seconds, the temperature rise was 1 ° C./min, the strain was 0.1%, and the complex elastic modulus and tangent loss were determined. The
(Toner shape factor)
The shape factor was determined by the following formula.

Shape factor = ((maximum diameter / 2) ² × π) × 100 / projection area Here, the maximum diameter is the distance between the parallel lines when the projected image of toner particles on a plane is sandwiched by two parallel lines. The width of the particle with the maximum spacing.

  The projected area refers to the area of the projected image of the toner particles on the plane.

  In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis.

At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
(Measuring method of particle size and particle size distribution)
The particle size and particle size distribution measurement in the present invention will be described. When the particle to be measured in the present invention is 2 μm or more, Coulter Multisizer II type (manufactured by Beckman Coulter Co.) was used as the measuring device, and ISOTON-II (manufactured by Beckman Coulter Co.) was used as the electrolyte.

  As a measuring method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant. This was added to 100 to 150 ml of the electrolytic solution.

  The electrolyte solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 to 60 μm is measured using the Coulter counter TA-II type with an aperture diameter of 100 μm. Volume average distribution and number average distribution were determined. The number of particles to be measured was 50,000.

  The toner particle size in the present invention was determined by the following method. With respect to the particle size range (channel) obtained by dividing the measured particle size distribution, a volume cumulative distribution is drawn from the smaller particle size, and the volume average particle size at 50% accumulation is defined as D50. The volume average particle diameter in the present invention is D50.

  The average particle size of the carrier was measured by taking a photograph with an electron microscope (FE-SEM), measuring the maximum and minimum diameters of 100 particles, and dividing the sum by 2 to determine the particle size of each particle. The diameter. The average particle size of the carrier is the average of the particle sizes of the individual particles. In addition, the average particle diameter about the core before performing resin coating was also measured by the same method.

-Preparation of crystalline resin 1
In a three-necked flask, 100 parts by mass of dimethyl decanoate, 75.0 parts by mass of 1,9-nonanediol and 0.08 parts by mass of dibutyltin oxide are reacted at 180 ° C. for 8 hours in a nitrogen atmosphere. During the reaction, generated water was removed out of the system. Thereafter, while gradually reducing the pressure, the temperature was raised to 230 ° C. and the reaction was performed for 7 hours, followed by cooling to obtain a crystalline resin. The weight average molecular weight of the crystalline resin 1 was 17000.
-Preparation of crystalline resin 2-
Adjust the crystalline resin 2 in the same way as the crystalline resin adjustment 1 except that the temperature was raised to 230 ° C. in the crystalline resin adjustment 1 and the reaction conditions for 7 hours were changed to 230 ° C. and 5 hours. Produced. The weight average molecular weight of the crystalline resin 2 was 14,000.
-Preparation of crystalline resin-
Adjust the crystalline resin 3 in the same way as the crystalline resin adjustment 1 except that the temperature was raised to 230 ° C in the crystalline resin adjustment 1 and the reaction conditions for 7 hours were changed to 210 ° C and 4 hours. Produced. The weight average molecular weight of the crystalline resin 3 was 10,000.
-Preparation of crystalline resin 4-
Adjust crystalline resin 4 in the same manner as crystalline resin adjustment 1 except that the temperature was raised to 230 ° C in crystalline resin adjustment 1 and the reaction conditions for 7 hours were changed to 240 ° C for 7 hours. Produced. The weight average molecular weight of the crystalline resin 4 was 19000.
-Preparation of crystalline resin 5-
Adjust the crystalline resin 5 in the same way as the crystalline resin adjustment 1 except that the temperature was raised to 230 ° C. in the crystalline resin adjustment 1 and the reaction conditions for 7 hours were changed to 250 ° C. and 8 hours. Produced. The weight average molecular weight of the crystalline resin 5 was 25000.

-Production of non-crystalline resin-
In a three-necked flask, 82 parts by mass of dimethyl terephthalate, 82 parts by mass of dimethyl isophthalate, 79 parts by mass of bisphenol A ethylene oxide adduct, 257 parts by mass of bisphenol A propylene oxide adduct, and 0.23 parts by mass of dibutyltin oxide were added in a nitrogen atmosphere. , Reacted at 180 ° C. for 3 hours. During the reaction, generated water was removed out of the system. Thereafter, while gradually reducing the pressure, the temperature was raised to 240 ° C. and reacted for 2 hours, followed by cooling to obtain an amorphous resin. The amorphous resin had a weight molecular weight of 16,500.
-Preparation of crystalline / amorphous mixed resin dispersion 1-
In a three-necked flask, 5 parts by mass of the above crystalline resin 1, 95 parts by mass of the above amorphous resin, 50 parts by mass of methyl ethyl ketone, and 15 parts by mass of isopropyl alcohol were added and stirred. After the resin is dissolved, 25 parts by mass of a 10% aqueous ammonia solution is added. Further, 400 parts by mass of ion-exchanged water was gradually added to carry out phase inversion emulsification, and then the solvent was removed. Then, the solid content concentration was adjusted to 25% to obtain a crystalline / amorphous mixed resin dispersion 1. . -Preparation of crystalline / amorphous mixed resin dispersion 2-
A crystalline / noncrystalline mixed resin dispersion 2 was prepared in the same manner as the crystalline / noncrystalline mixed resin dispersion 1 except that the crystalline resin 1 was changed to the crystalline resin 2.
-Preparation of crystalline / amorphous mixed resin dispersion 3-
A crystalline / noncrystalline mixed resin dispersion 3 was prepared in the same manner as the crystalline / noncrystalline mixed resin dispersion 1 except that the crystalline resin 1 was changed to the crystalline resin 3.
-Preparation of crystalline / amorphous mixed resin dispersion 4-
A crystalline / noncrystalline mixed resin dispersion 4 was prepared in the same manner as the crystalline / noncrystalline mixed resin dispersion 1 except that the crystalline resin 1 was changed to the crystalline resin 4.
-Preparation of crystalline / amorphous mixed resin dispersion 5-
A crystalline / noncrystalline mixed resin dispersion 5 was prepared in the same manner as the crystalline / noncrystalline mixed resin dispersion 1 except that the crystalline resin 1 was changed to the crystalline resin 5.
-Preparation of release agent dispersion-
Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting point 77 ° C.): 60 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 4 parts by mass Ion exchange water: 200 Part by mass A solution in which the above components were mixed was heated to 120 ° C. and dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), then dispersed with a Menton Gorin high-pressure homogenizer (Gorin), and volume averaged. A release agent dispersion was prepared by dispersing a release agent having a particle size of 250 nm. The water content was adjusted so that the mold release agent concentration of this dispersion was 20% by mass.
-Preparation of colorant dispersion-
Cyan pigment (copper phthalocyanine B15: 3, manufactured by Dainichi Seika Co., Ltd.): 50 parts by mass Nonionic surfactant Nonipol 400 (manufactured by Kao Corporation): 5 parts by mass Ion exchange water: 200 parts by mass After mixing and dissolving, the mixture was dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006), and the water content was adjusted to obtain a colorant particle dispersion (1).
-Manufacture of toner base particles 1-
-Crystalline / amorphous mixed resin dispersion 1: 720 parts by weight-Colorant dispersion: 50 parts by weight-Release agent dispersion: 70 parts by weight-Cationic surfactant-(Kao ( Co., Ltd .: Sanisol B50): 1.5 parts by mass The above components are contained in a round stainless steel flask, and 0.1 N sulfuric acid is added to adjust the pH to 3.8. 30 parts by mass of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by weight was added.

  Thereafter, the mixture was dispersed at 30 ° C. using a homogenizer (manufactured by IKA, Ultra Turrax T50), and then heated to 40 ° C. in an oil bath for heating. The volume average particle diameter of the obtained core aggregated particles was measured to be 5.2 μm.

  After this aggregated particle dispersion was held at 40 ° C. for 30 minutes, 160 parts by mass of the amorphous resin dispersion was gently added to the dispersion in which the core aggregated particles were formed, and held for 1 hour. The obtained adhered resin agglomerated particles had a volume average particle size of 6.2 μm. After adjusting the pH to 7.0 by adding 0.1 N nitric acid, the mixture was heated to 95 ° C. with continuous stirring and held for 5 hours.

Thereafter, the mixture was cooled to 20 ° C. at a rate of 20 ° C./min, filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner base particles. The obtained toner base particles 1 had a volume average particle size of 6.1 μm.
-Manufacture of toner base particles 2-
The toner base particles 2 are produced in the same manner as the toner base particles 1 except that the crystalline / amorphous mixed resin dispersion 1 is changed to the crystalline / amorphous mixed resin dispersion 2 in the manufacture of the toner base particles 1. Got. The obtained toner base particles 2 had a volume average particle size of 6.3 μm.
-Manufacture of toner base particles 3-
The toner mother particles 3 are produced in the same manner as the toner mother particles 1 except that the crystalline / amorphous mixed resin dispersion 1 is changed to the crystalline / amorphous mixed resin dispersion 3 in the production of the toner mother particles 1. Got. The obtained toner base particles 3 had a volume average particle size of 6.4 μm.
-Manufacture of toner base particles 4-
The toner base particles 4 are produced in the same manner as the toner base particles 1 except that the crystalline / non-crystalline mixed resin dispersion 1 is changed to the crystalline / non-crystalline mixed resin dispersion 4 in the production of the toner base particles 1. Got. The obtained toner base particles 4 had a volume average particle size of 5.9 μm.
-Manufacture of toner mother particles 5-
The toner base particles 5 are produced in the same manner as the toner base particles 1 except that the crystalline / noncrystalline mixed resin dispersion 1 is changed to the crystalline / noncrystalline mixed resin dispersion 5 in the production of the toner base particles 1. Got. The obtained toner base particles 5 had a volume average particle size of 5.8 μm.
-Manufacture of carriers-
Ferrite particles (volume average particle size: 50 μm): 100 parts by mass Toluene: 14 parts by mass Styrene-methyl methacrylate copolymer (component ratio: styrene / methyl methacrylate = 90/10, weight average molecular weight Mw = 80000): 2 parts by mass / carbon black (R330: manufactured by Cabot): 0.2 part by mass First, the above components excluding ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then this coating solution And ferrite particles were placed in a vacuum degassing type kneader, stirred at 60 ° C. for 30 minutes, degassed by further depressurization while heating, and dried to obtain a carrier.
-Production of developer-
For the toner base particles 1 to 5, 1.2 parts by weight of commercially available fumed silica RX50 (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive to 100 parts by weight of each toner base particle, and mixed with a Henschel mixer. Thus, toners 1 to 5 for developing an electrostatic image were obtained. Subsequently, 8 parts by mass of the toner and 100 parts by mass of the carrier were mixed to prepare a two-component developer.

  The above is the description of the method for producing the toner employed in the image forming apparatus 1 and the method for producing the two-component developer having the toner. Tables 1, 2, and 3 show the loss elastic modulus at 40 ° C., the ratio of the crystalline resin in the toner, and the shape factor of the toner as the results of the toners 1 to 5 described above.

In the following description, it is specifically described that the image forming method in which the image quality is not easily deteriorated is performed by employing the cleaning method described with reference to FIG. 1 and using the toner having characteristics suitable for avoiding the image quality deterioration. Verify with experimental data.
[Experiment 1]
In this experiment, the optimum loss elastic modulus of toner for good image formation will be verified. In this experiment, a color double-sided image having a patch portion with a density of 100% was output at 10,000 sheets at a high temperature and high humidity of 28 ° C. and 85% of humidity, and further at a low temperature and low humidity of 10 ° C. and 15% of humidity. A continuous output test is performed to output 10,000 sheets.

The continuous output test is performed by the following image forming apparatus.
(Example 1-1)
The above-mentioned continuous output test was performed on an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1, employing a developer prepared using the above-described electrostatic charge image developing toner 1.
(Example 1-2)
The above-mentioned continuous output test was performed on an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1 by using a developer produced using the above-described electrostatic charge image developing toner 2.
(Example 1-3)
The above-described continuous output test was performed with an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1, employing a developer prepared using the above-described toner 4 for developing an electrostatic image.
(Comparative Example 1-1)
The above-mentioned continuous output test was performed on an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1, employing a developer produced using the above-described electrostatic charge image developing toner 3.
(Comparative Example 1-2)
The above-mentioned continuous output test was performed on an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1, employing a developer produced using the above-described electrostatic charge image developing toner 5. For each of the above Examples 1-1 to 1-3, Comparative Example 1-1, and Comparative Example 1-2, the presence / absence of toner filming on the image carrier after continuous output and the above continuous output It is checked whether or not the influence of toner filming appears on the image quality at the end of the test. Check results are divided into the following categories.
○: No toner filming on the image carrier and good image quality Δ: Some toner filming is seen on the image carrier, but the effect on the image quality is small ×: Toner filming on the image carrier In addition, the image quality is deteriorated. In addition to the toner filming check, at the end of the continuous output test, the image output on both sides of the paper is checked for uneven gloss. This gloss unevenness is evaluated by dividing into the following categories.
○: Even if a patch part with a density of 100% is compared on both sides, gloss unevenness cannot be visually recognized. ×: When a patch part with a density of 100% is compared on both sides, gloss unevenness can be visually recognized. The results of Example 1-1 to Example 1-3, Comparative Example 1-1, and Comparative Example 1-2 are shown.

As can be seen from Table 1, the loss elastic modulus of the toner at 40 ° C. is the smallest value of 1 × 10 ⁸ [Pa], and the loss elastic modulus of the toner at 40 ° C. is 9 ×. In Comparative Example 1-2, which is the largest value of 10 ⁸ [Pa], gloss unevenness occurs (evaluation is x). On the other hand, in Examples 1-1 to 1-3 in which the loss elastic modulus of the toner at 40 ° C. is in the range of 2 × 10 ⁸ [Pa] to 7 × 10 ⁸ [Pa], uneven gloss is not observed. (Evaluation is ○).

If the loss elastic modulus is too small, the toner melts at a portion where the temperature is high on the paper too much, and gloss unevenness occurs on the formed image. On the other hand, if the loss elastic modulus is too large, the melting of the toner tends to be delayed at the low temperature portion on the sheet, and gloss unevenness is also generated on the formed image. In particular, in the case of double-sided output, since the temperature of the recording medium differs greatly before and after the heat treatment during fixing, gloss unevenness is likely to occur. The results in Table 4 reflect this, and as in Examples 1-1 to 1-3, the loss elastic modulus at 40 ° C. is 2 × 10 ⁸ [Pa] or more and 7 × 10 ⁸ [Pa]. It can be seen that the occurrence of uneven gloss can be avoided by employing a low melting point toner belonging to the following range.
[Experiment 2]
In this experiment, the ratio of the crystalline resin in the toner that is optimal for good image formation will be verified.

In this experiment, the same continuous output test as that performed in Experiment 1 is performed by the following image forming apparatus.
(Example 2-1)
The ratio of the mass parts of the crystalline resin 1 and the amorphous resin is changed from 5:95 to 8:92 in the process of “Preparation of the crystalline / amorphous mixed resin dispersion 1” in the toner production method described above. Except for the above, toner mother particles were obtained in the same manner as toner mother particles 1 to obtain a two-component developer. The above-described continuous output test was performed in an image forming apparatus having the same configuration as the image forming apparatus similar to the image forming apparatus 1 shown in FIG.
(Comparative Example 2-1)
The ratio of the mass parts of the crystalline resin 1 and the amorphous resin is changed from 5:95 to 1:99 in the process of “Preparation of the crystalline / amorphous mixed resin dispersion 1” in the toner production method described above. Except for the above, toner mother particles were obtained in the same manner as toner mother particles 1 to obtain a two-component developer. The above-described continuous output test was performed in an image forming apparatus having the same configuration as the image forming apparatus similar to the image forming apparatus 1 shown in FIG.

  Evaluation similar to Experiment 1 was performed about Example 2-1 and Comparative Example 2-1. Table 2 below shows the results of Example 2-1 and Comparative Example 2-1.

When Comparative Example 2-1 having a crystalline resin ratio of 1% is compared with Examples 2-1 and 1-1 having a crystalline resin ratio of 5% or more, Comparative Example 2-1 shows an image. While toner filming is observed on the holding member and the image quality is deteriorated (evaluation is x), in Example 2-1 and Example 1-1, toner filming does not exist on the image holding member. As a result, the image quality was good (evaluation was good). From the results of Table 2, it can be seen that when the proportion of the crystalline resin is low as in Comparative Example 2-1, the charge is not sufficiently injected into the toner and the cleaning property is low. As shown in 1-1, it can be seen that by using a toner having a crystalline resin ratio of 5% or more, the cleaning property is improved and toner filming is avoided.
[Experiment 3]
In this experiment, a toner shape factor that is optimal for good image formation will be verified.

In this experiment, the same continuous output test as that performed in Experiment 1 is performed by the following image forming apparatus.
(Example 3-1)
In the process of “manufacturing toner base particles 1” in the above-described toner manufacturing method, nitric acid is added to the adhered resin aggregated particles to bring the pH to 6, and the holding time after heating is increased from 5 hours to 7 hours. Thus, the continuous output test described above is performed in an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1 except that the toner whose toner shape coefficient is adjusted to 108 is used. Went.
(Example 3-2)
In the process of “manufacturing toner base particles” in the toner manufacturing method described above, the retention time after adding nitric acid to the adhered resin aggregated particles and heating them is reduced to 2 hours, so that the average value of the toner shape factor is reduced. The above continuous output test was performed on an image forming apparatus having the same configuration as that of the image forming apparatus 1 shown in FIG. 1 except that the toner adjusted to 130 was used.
(Example 3-3)
In the process of “manufacturing toner base particles” in the above-described toner manufacturing method, the retention time after adding nitric acid to the adhering resin aggregated particles and heating them is reduced to 1.5 hours. The above continuous output test was performed with an image forming apparatus having the same configuration as the image forming apparatus similar to the image forming apparatus 1 shown in FIG. 1 except that the toner whose value was adjusted to 150 was used. Evaluation similar to Experiment 1 was performed about Example 3-1, Example 3-2, and Example 3-3, respectively. Table 3 below shows the results of Example 3-1, Example 3-2 and Example 3-3.

When Example 3-3 having an average toner shape factor of 150 is compared with Examples 3-1 and 3-2 having an average value of 130 or more, the image in Example 3-3 is While toner filming is slightly observed on the support (evaluation is Δ), in Example 3-1 and Example 3-2, toner filming is not present on the image support (evaluation is ○ ). The closer the toner shape is to a sphere (the toner shape factor is closer to 100), the more uniform the toner surface charge distribution and the more stable the toner polarity, which is suitable for cleaning methods using electrostatic force. ing. From the results of Table 3, it can be seen that when the average value of the toner shape factor is 100 or more and 130 or less, sufficient cleaning performance is exhibited.
[Experiment 4]
In the above Experiments 1 to 3, the optimum toner characteristics for verifying the good image formation were verified. In this Experiment 4, the optimum cleaning method and the residual toner recovery were collected. Verify the optimum applied voltage.

In this experiment, a toner band having a surface density of 15 [g / m ² ] and a length of 300 mm is formed on the image carrier, and the image carrier is cleaned without primary transfer. After cleaning, a color double-sided image is output. In addition to the image output after toner band removal, the same continuous output test as that performed in Experiment 1 was also performed.

The image output after the toner band removal and the continuous output test are performed by the following image forming apparatus.
(Example 4-1)
The image is the same as that of the image forming apparatus 1 shown in FIG. 1 except that a voltage of 80 [V] is applied to the belt roll brush that removes residual toner on the image holding member with electrostatic force. Forming equipment.
(Example 4-2)
An image forming apparatus similar to the image forming apparatus 1 shown in FIG. 1, wherein a voltage of 100 [V] is applied to a belt roll brush that removes residual toner on the image holding member with an electrostatic force.
(Example 4-3)
An image forming apparatus similar to the image forming apparatus 1 shown in FIG. 1, wherein a voltage of 400 [V] is applied to a belt roll brush that removes residual toner on the image holding member with electrostatic force.
(Example 4-4)
An image similar to that of the image forming apparatus 1 shown in FIG. 1 except that a voltage of 420 [V] is applied to a belt roll brush that removes residual toner on the image holding member with an electrostatic force. Forming equipment.
(Comparative Example 4-1)
An image forming apparatus similar to the image forming apparatus 1 shown in FIG. 1 except that the image carrier is cleaned by a cleaning blade that is in pressure contact with the image carrier instead of the image carrier roll brush.

For each of Example 4-1 to Example 4-4 and Comparative Example 4-1, the cleaning performance after image output after toner band removal described above is checked based on the output image. The cleaning check results are evaluated in the following categories.
○: Image quality defect does not exist in the output image ×: Image quality defect such as white stripe or color stripe is seen in the output image In addition, each of Example 4-1 to Example 4-4 and Comparative Example 4-1 As in Experiment 1, toner filming and gloss unevenness at the end of the continuous output test are evaluated, and the degree of wear of the image carrier after the continuous output test is checked. The degree of wear is evaluated by dividing it into the following categories.
○: There is no noticeable wear on the surface of the image carrier, and the image quality at the end of the continuous output test is good. X: Wear is noticeable on the surface of the image carrier, and the image quality deteriorates at the end of the continuous output test. The results of 4-1 to Example 4-4 and Comparative Example 4-1 are shown.

  As can be seen from Table 4, Comparative Example 1 in which the image carrier is cleaned by the blade method, and Example 4-1 in which the residual toner is charged by the brush method and the image carrier is cleaned by electrostatic force. -Comparison with Examples 4-4, with respect to toner filming, in Comparative Example 1, toner filming was observed on the image carrier and image quality was deteriorated (evaluation was x). In Example 4-1 to Example 4-4, even in Example 4-1 and Example 4-4, which have the lowest evaluation, toner filming is slightly observed on the image carrier, but the effect on the image quality is not affected. The result is small (evaluation is Δ). For this reason, as a cleaning method for the image carrier, a cleaning method for cleaning the image carrier with an electrostatic force that does not require a strong pressure contact force such as a cleaning blade is adopted. It can be seen that the occurrence is avoided. Further, regarding cleaning performance, in Comparative Example 1, image quality defects such as white stripes and color stripes are observed in the output image (evaluation is x), whereas in Examples 4-1 to 4-4, output is performed. There is no image quality defect in the image (evaluation is ◯). In general, low-melting-point toner is easily crushed and difficult to remove. In the cleaning method using a cleaning blade, there is residual toner that passes through the gap between the blades. Such residual toner causes streak-like image quality defects in the image. The result of the comparative example 4-1 reflects this, and the image forming apparatus using the low melting point toner has an electrostatic force as in the example 4-1 to the example 4-4. It can be seen that a method of cleaning the image carrier using it is desirable.

  When comparison is made in Example 4-1 to Example 4-4, Example 4-1 in which the voltage applied to the roll brush for the belt is as small as 80 [V], and for the belt is used. In Example 4-4 in which the voltage applied to the roll brush was the largest at 420 [V], toner filming was slightly observed on the image holding member as a result of toner filming. In contrast to the result of small (evaluation is Δ), in Example 4-2 and Example 4-3 in which the applied voltage is 100 [V] or more and 400 [V] or less, toner filming is formed on the image carrier. It does not exist and the image quality is good (evaluation is good). The result of Example 4-1 is considered to indicate that when the voltage applied to the belt roll brush is 80 [V], the residual toner cannot be sufficiently removed and filming occurs. The result of Example 4-4 is that when the applied voltage is 420 [V], the applied voltage is too large, and the residual toner is charged to a polarity opposite to the charging polarity of the residual toner. it is conceivable that. Also in this case, the cleaning property is lowered, and the residual toner that has not been removed is also filmed. Considering the result of toner filming in Examples 4-1 to 4-4, it can be seen that the applied voltage is desirably 100 [V] or more and 400 [V] or less.

Summarizing the results of Experiment 1 to Experiment 4 described above, as toner characteristics, the ratio of the crystalline resin is 5% or more and the loss elastic modulus at 40 ° C. is 2 × 10 ⁸ [Pa] or more and 7 × 10 ^8. [Pa] By adopting a toner within the following range and adopting a method of charging and removing residual toner as a cleaning method, it is possible to avoid both toner filming and gloss unevenness. It is concluded that Furthermore, by adopting toner belonging to the region where the shape factor of the toner is 100 or more and 130 or less, and applying an applied voltage for charging the residual toner to 100 [V] or more and 400 [V] or less, high cleaning performance is realized. You can see that

  The image forming apparatus described above is a rotary type full color image forming apparatus. However, the image forming apparatus of the present invention may be applied to a tandem type full color image forming apparatus or a monochrome image forming apparatus.

1 is a diagram illustrating a schematic configuration of a full-color image forming apparatus corresponding to an embodiment of an image forming apparatus of the present invention.

Explanation of symbols

1 Image forming apparatus,
4 ... CPU,
10: Image carrier,
2 ... Intermediate transfer belt,
20: Charger,
300 ... Roll brush for image carrier,
301,811 ... hair,
302: Toner recovery voltage application unit,
31 ... Cleaning blade,
32 ... exposure unit,
40a ... primary transfer roll,
40b ... secondary transfer roll,
41a ... Primary transfer bias voltage application unit,
41b ... Secondary transfer bias voltage application unit,
50: Development rotary,
51, 52, 53, 54 ... developer,
60a, 60b, 60c, 60d ... support rolls,
6 ... Tray,
61: Paper feed roll,
62 ... Fixer,
81 ... Roll brush for belt,
82: toner charging voltage application unit,
100: Cleaning device,
101 ... Case

Claims (2)

In a cleaning device that removes residual toner from the surface of a cleaning object that is fixed on a recording medium and that holds a toner image on the surface,
The toner contains 5% by weight or more of a crystalline resin and has a loss elastic modulus at 40 ° C. of 2 × 10 ⁸ Pa or more and 7 × 10 ⁸ Pa or less,
A removing section that creates a potential difference with the object to be cleaned and removes the toner from the surface of the object to be cleaned by applying an electric force due to the potential difference to the toner;
A cleaning device comprising: a storage unit that at least temporarily stores toner removed by the removal unit. An image holding member is formed, a toner image is formed on the image holding member, and the toner image is transferred from the image holding member and fixed on the recording medium, whereby an image composed of the toner image is formed on the recording medium. In the image forming apparatus to be formed,
The toner contains 5% by weight or more of a crystalline resin and has a loss elastic modulus at 40 ° C. of 2 × 10 ⁸ Pa or more and 7 × 10 ⁸ Pa or less,
A removing part that removes the toner from the surface of the image carrier by causing a potential difference between the image carrier and an electric force caused by the potential difference on the toner, and the toner removed by the removing part An image forming apparatus comprising a cleaning device having at least a temporary storage portion.

Images