JP2010217767A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that is able to reduce the spent toner in a developer. <P>SOLUTION: The image forming apparatus includes: an image holder; a charger for charging a surface of the image holder; an exposure unit for exposing the charged surface of the image holder; a developing unit for forming a toner image on the surface of the image holder; an independent member which is arranged at the image holder and the surface potential which is independent of that of the image holder; and a charger for independent member, charging the surface of the independent member. The charger charges the image holder, excluding an end thereof, which is predetermined on the side reverse to the independent member. The developing unit includes a developing roll, having a developing section for conveying developer to an area facing other parts of the image holder, excluding a tip; a first non-developing section for conveying developer to an area facing the independent member; and a second non-developing section for conveying developer to the area facing the tip. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  In the developing device incorporated in the image forming apparatus, the storage tank is partitioned into a first storage chamber adjacent to the developing roll and a second storage chamber adjacent to the first storage chamber. There is one that moves the developer while stirring between the two storage chambers (see, for example, Patent Document 1).

JP-A-9-204105 (FIG. 5)

  An object of the present invention is to provide an image forming apparatus capable of reducing deteriorated toner in a developer.

An image forming apparatus according to claim 1 comprises:
An image carrier that forms an image on the surface and holds the image;
A charger for charging the surface of the image carrier;
An exposure unit that forms an electrostatic latent image on the surface by exposing the surface of the image carrier charged by the charger;
A developing device containing a developer containing the toner to form a toner image by attaching a toner to the latent image formed on the surface of the image carrier;
The charger charges the surface of the image carrier excluding a predetermined end on the image carrier;
An independent member, which is lined with the image carrier on the side opposite to the end, and whose surface potential is independent of the surface potential of the image carrier;
An independent member charger for charging the surface of the independent member;
The developer is
Adjacent to both the image carrier and the independent member, the image carrier and the independent member have a potential difference. The developer is held on the surface and rotated to rotate the developer. A developing roll that conveys the developer to an area facing the body and the independent member, wherein the developer is conveyed to a developing area facing the other part of the image holding body excluding the end portion. The image carrier is between the developing portion having a main potential difference and the independent member that conveys the developer to the first non-developing region facing the independent member in this region. A first non-developing portion having a first potential difference different from the main potential difference, and the image carrier for conveying the developer to a second non-developing region facing the end of the region. Having a second potential difference different from the main potential difference during A developing roll and a developing unit,
Adjacent to the developing roll and extending along the rotation axis of the developing roll, containing the developer inside and supplying the developer to the developing roll, stirring the contained developer on the rotating shaft A first accommodating portion that conveys in a first direction along;
Adjacent to the first housing part and extending side by side with the first housing part, both ends are provided with moving ports for moving the developer between the first housing part and containing the developer inside A second storage portion that is supplied with toner and conveys the developer and the toner in a second direction opposite to the first direction while stirring and mixing the developer;
And a toner supply unit for supplying toner to the second storage unit through a toner supply port.

An image forming apparatus according to claim 2
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier.

An image forming apparatus according to claim 3
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier,
From the main potential difference, the first non-developing part generates, as the first potential difference, an electric field having the same direction as the main electric field between the first non-developing part and the independent member body. Is also characterized by having a small potential difference.

An image forming apparatus according to claim 4
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier,
The first non-developing portion has a potential difference that generates an electric field opposite to the direction of the main electric field between the first non-developing portion and the independent member as the first potential difference. It is characterized by being.

An image forming apparatus according to claim 5
An exposure unit for an independent member that forms a potential distribution on the surface of the independent member;
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier,
From the main potential difference, the first non-developing part generates an electric field in the same direction as the main electric field as the first potential difference between the first non-developing part and the image carrier. The potential distribution simultaneously has both a small potential difference and a potential difference that generates an electric field opposite to the direction of the main electric field between the first non-development portion and the image carrier. It is characterized by.

An image forming apparatus according to claim 6
In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, so that the main potential difference and the Having a second potential difference,
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
By applying a potential to the second non-developing portion, a potential difference larger than the main potential difference between the second non-developing portion and the image carrier, and the image carrier and the developing portion And a large difference generation potential applying section for generating an electric field in the same direction as the main electric field generated between the two.

An image forming apparatus according to claim 7 is provided.
In the developing roll, the developing portion and the first non-developing portion are separated from each other, and different potentials are applied to the developing portion and the first non-developing portion, whereby the main potential difference and the first non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
By applying a potential to the first non-development portion, a potential difference smaller than the main potential difference and an electric field in the same direction as the main electric field are provided between the first non-development portion and the independent member. It is characterized in that a small difference generation potential applying unit is provided.

An image forming apparatus according to claim 8 is provided.
In the developing roll, the developing portion and the first non-developing portion are separated from each other, and different potentials are applied to the developing portion and the first non-developing portion, whereby the main potential difference and the first non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
Applying a potential to the first non-development part, applying a reverse electric field generation potential that generates an electric field opposite to the direction of the main electric field between the first non-development part and the independent member. It has the part.

An image forming apparatus according to claim 9 is provided.
In the developing roll, the developing portion and the first non-developing portion are separated from each other, and different potentials are applied to the developing portion and the first non-developing portion, whereby the main potential difference and the first non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the first non-developing part side to the second non-developing part side,
By applying a first potential to the first non-developing portion, a potential difference smaller than the main potential difference and the direction of the main electric field are the same between the first non-developing portion and the independent member. And applying a second potential to the first non-developing portion, the small non-developing portion and the independent member between the first non-developing portion and the independent member. It is characterized by having a potential applying section that also serves as a reverse electric field generating potential applying section that generates an electric field that is opposite to the direction of the main electric field, and is capable of switching between the first electric potential and the second electric potential. And

An image forming apparatus according to claim 10 is provided.
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
The first non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the first potential difference between the first non-development unit and the first non-development unit. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier.

An image forming apparatus according to claim 11 is provided.
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
The first non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the first potential difference between the first non-development unit and the first non-development unit. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier,
The second non-developing part generates, as the second potential difference, an electric field in the same direction as the main electric field between the second non-developing part and the independent member. It is characterized by having a small potential difference.

An image forming apparatus according to claim 12 is provided.
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
The first non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the first potential difference between the first non-development unit and the first non-development unit. It has a potential difference larger than the main potential difference generated between the image carrier and the image carrier,
The second non-developing portion has a potential difference that causes an electric field opposite to the direction of the main electric field to be generated between the second non-developing portion and the independent member as the second potential difference. It is characterized by being.

An image forming apparatus according to claim 13 is provided.
In the developing roll, the developing unit and the first non-developing unit are separated from each other, and different potentials are applied to the developing unit and the first non-developing unit, so that the main potential difference and the first non-developing unit are Having a first potential difference,
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
By applying a potential to the first non-developing portion, a potential difference larger than the main potential difference between the first non-developing portion and the image carrier, the image carrier and the developing portion, And a large difference generation potential applying section for generating an electric field in the same direction as the main electric field generated between the two.

An image forming apparatus according to claim 14 is provided.
In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, whereby the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
A small difference generation potential applying unit that generates a potential difference smaller than the main potential difference and an electric field in the same direction as the main electric field is provided between the independent member and the second non-developing unit. Features.

An image forming apparatus according to claim 15 is provided.
In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, whereby the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
A reverse electric field generating potential applying unit that generates an electric field opposite to the direction of the main electric field is provided between the independent member and the second non-developing unit.

An image forming apparatus according to claim 16 is provided.
In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, whereby the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first storage portion conveys the developer with the direction from the second non-developing portion side to the first non-developing portion side as the first direction;
A potential difference applying unit configured to apply a potential difference between the independent member and the second non-developing unit, wherein the developing unit and the image carrier are disposed between the independent member and the second non-developing unit; A potential difference that causes a potential difference smaller than the potential difference therebetween, and that the polarity of the relative potential of the independent member with respect to the second non-development portion is the same as the polarity of the relative potential of the image carrier with respect to the development portion, and And a potential difference applying unit that switches and applies a potential difference in which the polarity of the relative potential of the independent member with respect to the second non-developing unit is opposite to the polarity of the relative potential of the image carrier with respect to the developing unit. It is characterized by that.

  According to the image forming apparatus of the first aspect, it is possible to reduce the deteriorated toner in the developer.

  According to the image forming apparatus of the second and tenth aspects, the overcharged toner in the deteriorated toner in the developer can be removed at an effective location.

  According to the image forming apparatus of the third and eleventh aspects, the overcharged toner and the low-charged toner among the deteriorated toners in the developer can be removed at effective positions.

  According to the image forming apparatus of the fourth aspect and the twelfth aspect, it is possible to remove each of the overcharged toner and the reverse polarity toner out of the deteriorated toner in the developer at an effective location.

  According to the image forming apparatus of the fifth aspect, the overcharged toner, the lowly charged toner, and the reverse polarity toner among the deteriorated toners in the developer can be simultaneously removed at each effective place.

  According to the image forming apparatus of the sixth aspect and the thirteenth aspect, it is possible to reliably obtain a potential state in which the overcharged toner out of the deteriorated toner in the developer is removed.

  According to the image forming apparatus of the seventh aspect and the fourteenth aspect, it is possible to reliably obtain a potential state in which the low-charged toner out of the deteriorated toner in the developer is removed.

  According to the image forming apparatus of the eighth and fifteenth aspects, it is possible to reliably obtain a potential state in which the reverse polarity toner of the deteriorated toner in the developer is removed.

  According to the image forming apparatus of the ninth aspect and the sixteenth aspect, it is possible to selectively remove each of the low-charged toner and the reverse polarity toner out of the deteriorated toner in the developer.

1 is a schematic configuration diagram of a printer. FIG. 2 is a perspective view of the developing device shown in FIG. 1 from the laser exposure device side. It is sectional drawing of a developing device etc. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll, and the electric potential of each part in the printer of this embodiment. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll in the printer of 2nd Embodiment, and the electric potential of each part. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll in the printer of 3rd Embodiment, and the electric potential of each part. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll in the printer of 4th Embodiment, and the electric potential of each part. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll in the printer of 5th Embodiment, and the electric potential of each part. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll in the printer of 6th Embodiment, and the electric potential of each part. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll, and the electric potential of each part in the printer of 7th Embodiment. It is a perspective view from the laser exposure apparatus side of the developing device of 8th Embodiment. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll, and the electric potential of each part in the printer of 8th Embodiment. It is a figure which shows the mode of irradiation of the laser exposure light from the laser exposure device with respect to the photoreceptor roll, and the electric potential of each part in the printer of 9th Embodiment.

  Hereinafter, embodiments of the image forming apparatus of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a printer.

  A printer 1 shown in FIG. 1 generates a photoconductor roll 10, a charging roll 11 that applies a charge to the surface of the photoconductor roll 10, and laser exposure light based on an image signal transmitted from the outside. A laser exposure device 12 for irradiating the image, a developing device 13 for storing a developer containing toner, a paper cassette 16 for storing recording paper, and a paper transport device 17 for pulling out the recording paper from the paper cassette 16 and transporting it. A transfer roll 14 for transferring the toner image held on the surface of the photoreceptor roll 10 onto the recording paper conveyed in the direction of arrow B; and heating and pressurizing the toner image on the recording paper on the recording paper A fixing device 15 that fixes the toner image on the surface, a cleaning device 20 that cleans the surface of the photoreceptor roll 10, and image data transmitted from the outside. To have an exposure control unit 100 to be transmitted to the laser exposure device 12. The developing device 13 rotates while facing the photoconductor roll 10 and conveys the developer to an area between the photoconductor roll 10 and a toner supply unit that supplies toner to the inside of the developing device 13. 130. Further, the developing device 13 has a toner concentration sensor (not shown) and a density control unit for keeping the toner concentration in the developer contained in the developing device 13 constant. The density control unit issues a toner supply instruction to the toner supply unit 130 in accordance with the result detected by the toner density sensor. In addition to the toner, the developer contained in the developing unit 13 includes a magnetic carrier that is a charge-providing particle and a magnetic particle that frictionally charges the toner by friction with the toner.

  Here, the flow of the image forming operation in the printer 1 will be briefly described.

  In the printer 1 shown in FIG. 1, an electric charge is applied to the surface of the photoreceptor roll 10 rotating in the direction of arrow A by the charging roll 11, and the image transmitted from the outside to the surface of the photoreceptor roll 10 to which the charge is applied. The laser exposure light based on the signal is irradiated from the laser exposure device 12, whereby an electrostatic latent image is formed on the surface. The developer accommodated in the developing unit 13 is supplied to the surface of the developing roll 133 and is transported to a region between the developing roll 133 and the photoreceptor roll 10, although the mechanism will be described later. The electrostatic latent image on the surface of the photoreceptor roll 10 is developed by the toner inside. The toner image obtained by this development is transferred by the transfer roll 14 onto the recording paper conveyed in the arrow B direction. Thereafter, the toner image on the recording paper is melted and fixed on the recording paper by a fixing device 15 that heats and pressurizes the toner image. The residue remaining on the portion of the photoreceptor roll 10 where the toner image has been transferred is downstream of the transfer roll 14 in the direction of arrow A and upstream of the charging roll 11 and on the photoreceptor roll. 10 is removed by the cleaning member 21 whose tip is in contact with the entire width along the rotation center. The removed residue is stored in the residue storage box 22. The printer 1 is a first embodiment of the image forming apparatus of the present invention, and the photoreceptor roll 10 corresponds to an example of the image carrier referred to in the present invention. The charging roll 11 corresponds to an example of a charger according to the present invention, and the laser exposure device 12 corresponds to an example of an exposure device according to the present invention. The developing device 13 corresponds to an example of a developing device according to the present invention. Further, the printer 1 is a monochromatic image dedicated machine, but the present invention may be applied to a color image machine.

  In the printer 1 of the present embodiment, a low-temperature fixing toner that can be fixed at a low temperature is used to suppress heat generation in the fixing device 15. Details of the low-temperature fixing toner will be described later.

  FIG. 2 is a perspective view of the developing device shown in FIG. 1 from the laser exposure device side.

  FIG. 2 shows a developing device 13 including a developing roll 133, a developer storage tank 132 for storing the developer, and an agitating and conveying member 131 for agitating and conveying the developer.

  The developer storage tank 132 has a first storage chamber 132a adjacent to the development roll 133 and a second storage chamber adjacent to the first storage chamber 132a by a wall 1321 extending in parallel with the development roll 133. 132b. In each of the first storage chamber 132a and the second storage chamber 132b, one agitation transport member 131 is provided. Specifically, the agitation transport member 131 includes a spiral fin around the rod. It has a provided structure. As the agitating and conveying member 131 provided in each of the first accommodation chamber 132a and the second accommodation chamber 132b rotates in the opposite directions, the developer accommodated in the developer accommodating tank 132 is agitated around the wall 1321. Is circulated in the direction of the arrow shown in the developer storage tank. Inside the developer storage tank 132, the toner and the magnetic carrier are agitated by the agitating and conveying member 131, so that the toner is negatively charged and the magnetic carrier is positively charged. For this reason, the negatively charged toner adheres electrostatically to the magnetic carrier. As a result, the toner and the magnetic carrier are naturally integrated inside the developer storage tank 132.

  FIG. 2 also shows a toner supply port 132c for receiving new toner from the toner supply unit 130 shown in FIG.

  Here, under a situation where image formation with a low image density continues for a long time and new toner is not supplied much, the toner in the developing device is mixed with the magnetic carrier. This increases the tendency of the external additive attached to the toner surface to be buried or detached. For this reason, the charge amount distribution of the toner, which is originally in a narrow range, is easily expanded. In particular, the tendency is remarkable in the case of the above-described low-temperature fixing toner. If such an enlargement of the charge amount distribution of the toner in the developing device is left unattended, the charge of the overcharged toner located on the high charge side of the enlarged charge amount distribution will be the image of the subsequent high image density. By the start of formation, the toner rapidly moves to new toner supplied in large quantities to the developing device. As a result, inside the developing unit, a newly charged toner is deprived of charge, and a newly charged toner with a slow increase in charge amount due to deterioration of charging performance due to friction with the magnetic carrier, It is easy to generate a so-called reverse polarity toner in which the charge polarity is reversed due to the charge taken away by the supplied toner. Among these toners in the developing unit, low-charge toners are insufficiently charged and thus have a weak electrostatic connection with the magnetic carrier, and will adhere to the electrostatic latent image when separated from the magnetic carrier. Instead, it splashes outside the developing unit and contaminates the inside of the apparatus. In addition, the reverse polarity toner of these toners inside the developing device adheres to the background area other than the part where the electrostatic latent image formed on the surface of the photoreceptor roll 10 is formed and deteriorates the image quality. Let

  Therefore, in the printer 1 of the present embodiment, a detailed description of the mechanism will be given later, but in addition to the overcharged toner that causes the generation of the low-charge toner and the reverse polarity toner, the generated low-charge toner and the reverse polarity are generated. The toner is also removed from the developer storage tank 132. Hereinafter, the description will be continued by returning to FIG.

  In FIG. 2, the upstream side transport roll 135 and the development roll 133 provided coaxially with the upstream side transport roll 135 from the upstream side to the downstream side in the developer transport direction in the first storage chamber 132 a of the development storage tank 132. And a downstream-side transport roll 134 provided coaxially with the developing roll 133. Although the upstream-side transport roll 135, the developing roll 133, and the downstream-side transport roll 134 are of the same axis, the same diameter, the same material, and the same structure, they are different members and are given different potentials. Is done.

  Further, the developing roll 133 is provided to face the main portion 10 a of the main portion 10 a and the end portion 10 b constituting the photoconductor roll 10, and the downstream transport roll 134 constitutes the photoconductor roll 10. The main portion 10a and the end portion 10b are provided to face the end portion 10b. Further, the upstream-side transport roll 135 is provided to face the suction roll 40.

  The upstream transport roll 135 corresponds to an example of the first non-developing portion referred to in the present invention, and the developing roll 133 corresponds to an example of the developing portion referred to in the present invention. Further, the downstream-side transport roll 134 corresponds to an example of a second non-developing portion referred to in the present invention. A combination of the developing roll 133, the downstream conveying roll 134, and the upstream conveying roll 135 corresponds to an example of the developing roll referred to in the present invention. The suction roll 40 corresponds to an example of an independent member referred to in the present invention.

  In FIG. 2, the secondary charging roll 50 that charges the suction roll 40 and the main portion 10 a of the photosensitive body 10 of the photosensitive roll 10 are provided to face the suction roll 40. A charging roll 11 for charging the main portion 10a is shown. The auxiliary charging roll 50 corresponds to an example of the independent member charger according to the present invention.

  Further, FIG. 2 shows a range Y through which the recording paper passes and a direction X through which the recording paper passes as viewed from the laser exposure device 12 side. The range Y through which the recording paper passes between the dotted lines shown in FIG. 2 coincides with the main portion 10a of the photoreceptor roll 10, and therefore the surface of the end 10b of the photoreceptor roll 10 and the surface of the suction roll 40 The recording paper does not pass through.

  FIG. 3 is a cross-sectional view of the developing device and the like.

  Part (a) of FIG. 3 shows a state in which the AA cross section of the developing unit or the like shown in FIG. 2 is viewed in the direction of the arrow, and part (b) of FIG. A state in which the BB cross section of the developing device or the like is viewed in the direction of the arrow is shown.

  Here, the developing roll 133, the upstream side transport roll 135, and the downstream side transport roll 134 are all the cylindrical member 1331 that rotates in the direction of arrow C, and the cylindrical member 1331, A permanent magnet roll 1332 fixed independently. The permanent magnet roll 1332 has a plurality of magnetic poles arranged in the circumferential direction of the cylindrical member 1331 and has a magnetic force distribution that regulates adsorption and release of the developer.

  The developing roller 133, the upstream transport roll 135, and the rotating cylindrical member 1331 of the downstream transport roll 134 are supplied with developer while passing through the developer storage tank by the magnetic distribution of the permanent magnet roll 1332 inside. Then, the supplied developer is conveyed to a region formed between the photoreceptor roll 10.

  In the printer 1, as will be described in detail later, a toner image serving as an image base is formed by the cooperation of the developing roll 133 and the main portion 10 a of the photosensitive roll 10 facing the developing roll 133. Due to the cooperation of the upstream transport roll 135 and the suction roll 40 facing the upstream transport roll 135, the low-charge toner and the reverse polarity toner that are deteriorated toners from the developer held on the surface of the upstream transport roll 135 are removed. Both are adsorbed. Further, due to the cooperation of the downstream-side transport roll 134 and the end portion 10b of the photosensitive roll 10 facing the downstream-side transport roll 134, the developer that is held on the surface by the downstream-side transport roll 134 is excessively deteriorated toner. Charged toner is adsorbed.

  FIG. 4 is a diagram showing a state of irradiation of laser exposure light from a laser exposure device to a photosensitive roll and potentials of respective parts in the printer of this embodiment.

  FIG. 4 shows a state in which the laser exposure light from the laser exposure device 12 is applied to the main portion 10a of the photoreceptor roll 10 and the suction roll 40. The irradiation range and intensity of the laser exposure light of the laser exposure device 12 are controlled by the exposure control unit 100 shown in FIG.

  The photoreceptor roll 10, the suction roll 40, the developing roll 133, the upstream transport roll 135, and the downstream transport roll 134 shown in FIG.

  The main portion 10a of the photoreceptor roll 10 shown in FIG. 4 has a potential of −720 V due to charging by the charging roll 11, but the potential of the latent image portion formed by irradiation of the laser exposure light from the laser exposure device 12 is. Becomes −300V, while the potential of the portion not irradiated with the laser exposure light remains −720V. The end portion 10b of the photoreceptor roll 10 is maintained at a potential of 0 V without being charged. Further, although the suction roll 40 has a potential of −720 V by the sub-charging roll 50, the main portion side portion (hereinafter, this portion is referred to as the main portion side suction portion 41) by controlling the irradiation intensity of the laser exposure light. The potential of the remaining portion (hereinafter, this portion is referred to as the non-main portion adsorption portion 42) is -250V.

  Further, the potential of the developing roll 133 is set to −600 V by a power supply device (not shown), and the potential of the downstream transport roll 134 is set to −800 V by the first power supply 141 connected to the downstream transport roll 134. . Further, the potential of the upstream side transport roll 135 is set to −500 V by the second power source 142 connected to the upstream side transport roll 135. The first power supply 141 corresponds to an example of the large difference generation potential applying unit referred to in the present invention.

  Due to the above potential relationship, in this printer 1, the toner that adheres electrostatically to the magnetic carrier held on the developing roll 133 and is transported to the area formed between the photosensitive roll 10 is as described above. In the developer storage tank 132, the developing roller is charged from the latent image portion (potential is −300 V) generated between the latent image portion of the main portion 10a of the photosensitive roll 10 because it is charged with a negative polarity. An electrostatic field (potential difference is 300 V) directed to 133 (potential is −600 V) overcomes the electrostatic attraction with the magnetic carrier and flies to the latent image side, and the latent image is developed with toner. Thereafter, the magnetic carrier remains in a state of being attracted by a magnetic force to the surface of the cylindrical member 1331 of the developing roll 133 and is collected into the developer containing tank 132.

  Further, in the printer 1, the deteriorated toner in the developer is removed as follows by the above potential relationship.

  Overcharged toner among the toner that is electrostatically attached to the magnetic carrier held by the downstream-side transport roll 134 and transported to the region formed between the end 10b of the photoreceptor roll 10 is the end of the toner. The latent image portion of the main portion 10a of the photosensitive roll 10 and the developing roll 133 from the end portion 10b (potential is 0V) to the downstream transport roll 134 (potential is −800V) generated between the developing portion 133 and the portion 10b. The electric field (potential difference is 800 V) stronger than the electric field (potential difference is 300 V) between the latent image portion and the developing roll 133 while being in the same direction as the electric field between Adsorbed to the end 10b. Thereafter, the overcharged toner adsorbed on the end portion 10b is removed from the end portion 10b by the cleaning member 21 of the cleaning device 20 without being transferred because the transfer roll 14 is not present, and is stored in the residue storage box 22. The In this way, the cause of the generation of the low-charge toner and the reverse polarity toner is reduced by removing the overcharged toner from the deteriorated toner. In addition, since the removal of the overcharged toner is performed immediately before the position where the new toner is supplied, which is the most downstream in the developer transport direction in the first storage chamber 132a of the developer storage tank 132, the low charge toner is low. Generation of charged toner and reverse polarity toner is effectively suppressed.

  On the other hand, the reverse polarity toner out of the toner that is electrostatically attached to the magnetic carrier held by the upstream-side transport roll 135 and transported to the area formed between the suction roll 40 and The photosensitive member of the photoreceptor roll 10 that is generated between the upstream side conveyance roll 135 (potential is −500 V) and travels to the main portion side suction section 41 (potential is −620 V). By the electric field opposite to the electric field between the latent image portion of the main part 10a and the developing roll 133, the electrostatic attraction between the magnetic carrier and the main part side adsorption part 41 is adsorbed. Further, the low-charged toner among the toners electrostatically attached to the magnetic carrier held on the upstream-side transport roll 135 and transported to the area formed between the suction roll 40 and Photosensitivity of the photoconductor roll 10 that occurs between the non-main-part-side suction part 42 and the non-main-part-side suction part 42 (potential is −250 V) toward the upstream transport roll 135 (potential is −500 V). An electric field (potential difference is 250 V) which is in the same direction as the electric field between the latent image portion of the main part 10 a of the body 10 and the developing roll 133 but weaker than the electric field (potential difference 300 V) between the latent image portion and the developing roll 133. Thus, the electrostatic attraction between the magnetic carrier is overcome and the non-main portion-side attracting portion 42 is attracted. The reverse polarity toner and the low-charge toner simultaneously adsorbed on the adsorbing roll 40 are simultaneously removed from the adsorbing roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred, and are stored in the residue storage box 22. The For this reason, even if low-charged toner or reverse-polar toner is generated despite the above-described removal of the overcharged toner, scattering of the low-charged toner to the outside of the developing device and adhesion of the reverse-polar toner to the background are suppressed. . That is, the removal of the overcharged toner and the removal of the lowly charged toner and the reverse polarity toner exhibit a synergistic effect. For this reason, even when a low-temperature fixing toner that is easily deteriorated as in the present embodiment is employed, the occurrence of low-charge toner and reverse-polar toner is sufficiently suppressed. Further, since the low-charge toner and the reverse polarity toner are simultaneously removed, both the scattering of the low-charge toner to the outside of the developing device and the adhesion of the reverse polarity toner to the background are always suppressed. Further, the removal of the low-charge toner and the reverse polarity toner is the most upstream in the developer transport direction in the first storage chamber 132a of the developer storage tank 132, and the toner by the cooperation of the developing roll 133 and the photoreceptor roll 10 is used. Since it is performed at a position immediately before the image formation, a decrease in density of the toner image and a decrease in image quality due to the toner being placed on the background are suppressed.

  Next, a second embodiment of the image forming apparatus of the present invention will be described.

  The difference between the first embodiment and the second embodiment lies in the potential relationship between the suction roll 40 and the upstream transport roll 135, and other configurations and operations are the same. Only will be described.

  FIG. 5 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoconductor roll and a potential of each part in the printer of the second embodiment.

  FIG. 5 shows a state in which the irradiation range of the laser exposure light by the laser exposure device 12 provided in the second embodiment is limited to the main portion 10 a of the photoconductor roll 10. For this reason, the adsorption roll 40 maintains −720 V applied by charging by the sub-charging roll 50.

  Further, FIG. 5 shows the potential applied to the upstream transport roll 135 between the second power supply 142 that applies a potential of −500 V to the upstream transport roll 135 and the third power supply 143 that applies a potential of −1000 V. A change-over switch 138 that can be freely changed is shown.

  When the second power supply 142 is connected to the upstream transport roll 135, the second power supply 142 is electrostatically attached to the magnetic carrier held by the upstream transport roll 135 and transported to the area formed between the suction roll 40. The reverse polarity toner among the toners thus generated is generated between the suction roll 40 (potential is −720V) and is directed to the suction roll 40 from the upstream transport roll 135 (potential is −500V). By the electric field opposite to the electric field between the latent image portion of the main portion 10 a and the developing roll 133, the electrostatic attraction between the magnetic carrier and the magnetic carrier is overcome and attracted to the attracting roll 40. Thereafter, the reverse polarity toner adsorbed by the adsorbing roll 40 is removed from the adsorbing roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred, and is accommodated in the residue accommodating box 22. In addition, when the third power source 143 is connected to the upstream transport roll 135, the region that is electrostatically attached to the magnetic carrier held by the upstream transport roll 135 and is formed between the suction roll 40 The low-charged toner among the toner transported to the photosensitive member is generated between the suction roll 40 and the photosensitive roll that travels from the suction roll 40 (potential is −720 V) to the upstream transport roll 135 (potential is −1000 V). An electric field (potential difference is 280 V) which is in the same direction as the electric field between the latent image portion of the main portion 10 b of the body roll 10 and the developing roll 133 but is weaker than the electric field (potential difference 300 V) between the latent image portion and the developing roll 133. ) To overcome the electrostatic attractive force between the magnetic carrier and the magnetic carrier. Thereafter, the low-charged toner adsorbed on the adsorbing roll 40 is removed from the adsorbing roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred, and is stored in the residue storage box 22. That is, in the present embodiment, the changeover switch 138 selectively switches the removal of the low-charged toner and the removal of the reverse polarity toner. The adsorption of the overcharged toner and the formation of the toner image have already been described and will be omitted. The second power source 142 is an example of a reverse electric field generation potential applying unit according to the present invention, and the third power source 143 is an example of a small difference generation potential applying unit according to the present invention. The changeover switch 138 is an example of the potential applying unit referred to in the present invention.

  Next, a third embodiment of the image forming apparatus of the present invention will be described.

  The difference between the third embodiment and the first embodiment is that, in the first embodiment, the developing roll 133 and the upstream transport roll 135 which are separate members in the first embodiment are integrated in the third embodiment. Since the other configuration and operation are the same, only the difference will be described below.

  FIG. 6 is a diagram showing a state of irradiation of laser exposure light from a laser exposure device to a photoconductor roll and a potential of each part in the third embodiment.

  FIG. 6 shows a developer holding roll 233 in which the developing roll 133 and the upstream-side transport roll 135, which are separate members in the first embodiment, are integrated. The potential of the developer holding roll 233 is set to −600 V by a power source (not shown).

  Further, FIG. 6 shows a state in which the potential of the main portion side suction portion 41 of the suction roll 40 is set to −720V and the potential of the non-main portion side suction portion 42 is set to −350V.

  Due to the above potential relationship, the reverse polarity toner among the toners electrostatically attached to the magnetic carrier held on the developer holding roll 233 and conveyed to the area formed between the suction roll 40 is A photoconductor roll that is generated between the developer holding roll 233 (potential is −600 V) and the main section side suction section 41 (potential is −720 V) generated between the suction roll 40 and the main section side suction section 41. By the electric field opposite to the electric field between the latent image portion of the ten main portions 10a and the developer holding roll 233, the electrostatic attraction between the magnetic carriers is overcome and is attracted to the main portion-side attracting portion 41. Further, the low-charged toner among the toner electrostatically attached to the magnetic carrier and conveyed to the region formed between the suction roll 40 and the non-main-part side suction portion 42 of the suction roll 40. And the latent image portion of the main portion 10a of the photoreceptor roll 10 and the developer from the non-main portion side adsorption portion 42 (potential is −350V) to the developer holding roll 233 (potential is −600V). Although the electric field is in the same direction as the electric field between the holding roll 233 and the electric field (potential difference is 250 V) that is weaker than the electric field between the latent image portion and the developer holding roll 233 (potential difference is 250 V), It overcomes the electric attractive force and is attracted to the non-main part-side attracting part 42. The reverse polarity toner and the low-charged toner simultaneously adsorbed on the adsorption roll 40 in this manner are then simultaneously removed from the adsorption roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred, and the residue container 22 Is housed in. That is, in this embodiment, the electrical control is simplified by integrating the developing roll 133 and the upstream transport roll 135. The adsorption of the overcharged toner and the formation of the toner image have already been described and will be omitted.

  Next, a fourth embodiment of the image forming apparatus of the present invention will be described.

  The difference between the fourth embodiment and the third embodiment lies in the potential of the suction roll 40 that sucks the deteriorated toner, and other configurations and operations are the same. Therefore, only this difference will be described below.

  FIG. 7 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoreceptor roll and a potential of each part in the printer of the fourth embodiment.

  FIG. 7 shows a state in which the irradiation range of the laser exposure light by the laser exposure device 12 is limited to the main portion 10a of the photoconductor roll 10. For this reason, the adsorption roll 40 maintains −720 V applied by charging by the sub-charging roll 50.

  Due to the above potential relationship, the reverse polarity toner among the toners electrostatically attached to the magnetic carrier held on the developer holding roll 233 and conveyed to the area formed between the suction roll 40 is The latent image portion of the main portion 10a of the photosensitive roll 10 and the developer, which are generated between the developer holding roll 233 (potential is −600V) and the suction roll 40 (potential is −720V). By the electric field opposite to the electric field between the holding roll 233 and the electrostatic attraction with the magnetic carrier, it is attracted to the attracting roll 40. That is, it is fixed to remove the reverse polarity toner on the upstream side in the developer transport direction of the developer storage tank 132. The adsorption of the overcharged toner and the formation of the toner image have already been described and will be omitted.

  Next, a fifth embodiment of the image forming apparatus of the present invention will be described.

  The difference between the fifth embodiment and the first embodiment is that, in the first embodiment, the downstream transport roll 134 and the developing roll 133 are separate members, whereas in the fifth embodiment, the downstream transport is performed. Since the roll 134 and the developing roll 133 are integrated, and the other configurations and operations are the same, only the difference will be described below.

  FIG. 8 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoconductor roll and a potential of each part in the printer of the fifth embodiment.

  FIG. 8 shows a developer holding roll 233 in which the downstream transport roll 134 and the developing roll 133, which are different members, are integrated in the first embodiment.

  The potential of the developer holding roll 233 shown in FIG. 8 is the same as the potential in the first embodiment, except that it is set to −600 V by a power source (not shown).

  Due to the above potential relationship, the overcharged toner among the toners electrostatically attached to the magnetic carrier held on the developer holding roll 233 and conveyed to the area formed with the photoreceptor roll 10 is: A latent image of the main portion 10a of the photoconductor roll 10 that is generated between the end portion 10b of the photoconductor roll 10 and the developer holding roll 233 (potential is -600V) from the end portion 10b (potential is 0V). The electric field (potential difference is 600V) stronger than the electric field between the latent image portion and the developer holding roll 233 while being in the same direction as the electric field between the portion and the developer holding roll 233, It overcomes the electric attractive force and is attracted to the end 10b. Thereafter, the overcharged toner adsorbed on the end portion 10 b is removed from the end portion 10 b by the cleaning member 21 of the cleaning device 20 without being transferred, and stored in the residue storage box 22. In other words, the electrical control is simplified by integrating the downstream-side transport roll 134 and the developing roll 133. Incidentally, the adsorption of the low-charge toner and the reverse polarity toner and the formation of the toner image have already been described, and therefore will be omitted.

  Next, a sixth embodiment of the image forming apparatus of the present invention will be described.

  The difference between the sixth embodiment and the fifth embodiment is that, in the fifth embodiment, the irradiation range of the laser exposure light is the main portion 10a of the photoconductor roll 10 and the suction roll 40, whereas in the sixth embodiment. Since only the main portion 10a of the photoconductor roll 10 is present and the potential relationship between the suction roll 40 and the upstream-side transport roll 135 associated therewith, the other configurations and operations are the same. Only this difference will be described.

  FIG. 9 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoreceptor roll and a potential of each part in the printer of the sixth embodiment.

  FIG. 9 shows a state in which the irradiation range of the laser exposure light from the laser exposure device 12 is only the main part a of the photoreceptor roll 10.

  FIG. 9 shows the potential applied to the upstream transport roll 135 between the second power supply 142 that applies a potential of −500 V to the upstream transport roll 135 and the third power supply 143 that applies a potential of −1000 V. A change-over switch 138 that can be freely changed is shown.

  Each of the case where the second power source 142 is connected to the upstream side transport roll 135 and the case where the third power source 143 is connected to the upstream side transport roll 135 have already been described in the second embodiment shown in FIG. It is omitted here. In other words, in this embodiment, the downstream transport roll 134 and the developing roll 133 are integrated to simplify electrical control and to selectively remove low-charged toner and reverse-polar toner. It has been switched to. The adsorption of the overcharged toner and the formation of the toner image have already been described and will be omitted.

  Next, a seventh embodiment of the image forming apparatus of the present invention will be described.

  The difference between the seventh embodiment and the fifth embodiment is that, in the fifth embodiment, the developer holding roll 233 and the upstream transport roll 135 are separate members, whereas in the seventh embodiment, these developments are performed. Since the agent holding roll 233 and the upstream-side transport roll 135 are integrated with each other and the potential relationship associated therewith is the same in other configurations and operations, only this difference will be described below. .

  FIG. 10 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoreceptor roll and a potential of each part in the printer of the seventh embodiment.

  FIG. 10 shows a long roll 333 in which the developer holding roll 233 and the upstream transport roll 135 are integrated.

  The potential relationship regarding the adsorption of the overcharged toner by the end portion 10b of the photoreceptor roll 10 in the seventh embodiment has already been described in FIG. 8, and the adsorption of the low-charged toner and the reverse polarity toner by the adsorption roll 40 is also described. Is already described in FIG. 6, and the description thereof is omitted here. In the present embodiment, the developer holding roll 233 and the upstream-side transport roll 135 are integrated, thereby simplifying electrical control and reducing the number of parts.

  Next, an image forming apparatus according to an eighth embodiment of the present invention will be described.

  FIG. 11 is a perspective view of the developing device of the eighth embodiment from the laser exposure device side.

  In FIG. 11, the main portion 10 a of the photoreceptor roll 10 faces the developing roll 133, the end portion 10 b of the photoreceptor roll 10 faces the upstream transport roll 135, and the suction roll 40 transports downstream. A state of facing the roll 134 is shown.

  FIG. 11 shows a state in which the main portion 10 a of the photoreceptor roll 10 faces the charging roll 11 and the suction roll 40 faces the sub charging roll 50.

  Further, FIG. 11 shows a range Y through which the recording paper passes and a direction X through which the recording paper passes as viewed from the laser exposure device 12 side. The range Y through which the recording paper passes between the dotted lines shown in FIG. 11 matches the width of the main portion 10a of the photosensitive roll 10, and therefore the end portion 10b of the photosensitive roll 10 and the suction roll 40. The recording paper does not pass through the surface.

  In the present embodiment, a toner image as an image base is formed by the cooperation of the developing roll 133 and the main portion 10a of the photosensitive roll 10 facing the developing roll 133, while the upstream conveying roll 135 Both the low-charged toner and the reverse-polarized toner that are deteriorated toners from the developer held on the surface of the upstream-side transport roll 135 by cooperation with the end portion 10b of the photosensitive roll 10 facing the upstream-side transport roll 135. Is adsorbed to the end portion 10b of the photoreceptor roll 10. Further, by the cooperation of the downstream-side transport roll 134 and the suction roll 40 facing the lower-side transport roll 134, the overcharged toner that is a deteriorated toner is removed from the developer held on the surface by the downstream-side transport roll 134. 40 is adsorbed.

  FIG. 12 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoconductor roll and a potential of each part in the printer of the eighth embodiment.

  FIG. 12 shows that the irradiation range of the laser exposure light from the laser exposure device 12 is limited to only the main portion 10a of the photoconductor roll 10 and does not reach the end portion 10b of the photoconductor roll 10 and the suction roll 40. Has been.

  FIG. 12 also shows the potential applied to the upstream transport roll 135 between the fifth power supply 145 that applies a potential of 200 V to the upstream transport roll 135 and the sixth power supply 146 that applies a potential of −200 V. A changeover switch 138 that can be changed is shown.

  The photoreceptor roll 10, the suction roll 40, the developing roll 133, the upstream transport roll 135, and the downstream transport roll 134 shown in FIG. Although the main portion 10a of the photoreceptor roll 10 has a potential of −720V due to charging by the charging roll 11, the potential of the latent image portion formed by irradiation of the laser exposure light from the laser exposure device 12 becomes −300V. On the other hand, the potential of the portion not irradiated with the laser exposure light remains -720V. The end portion 10b of the photoreceptor roll 10 maintains a potential of 0V, and the suction roll 40 maintains a potential of −720V applied by charging by the sub charging roll 50. Further, the potential of the developing roll 133 is set to −600 V by a power supply (not shown), and the downstream transport roll 134 is connected to the fourth power supply 144 so that the potential is −1500 V.

  Due to the above potential relationship, the toner electrostatically attached to the magnetic carrier held on the developing roll 133 and conveyed to the area formed between the photosensitive roll 10 and the developer containing tank as described above. Since it is negatively charged in 132, the latent image portion (potential is −300 V) generated between the latent image portion of the main portion 10a of the photoreceptor roll 10 and the developing roll 133 (potential is −−). 600V) by an electric field (potential difference is 300V), and overcomes the electrostatic attraction between the magnetic carrier and fly to the latent image side, and the latent image is developed with toner. The overcharged toner among the toners electrostatically attached to the magnetic carrier held on the downstream-side transport roll 134 and transported to the area formed between the suction roll 40 and the suction roll 40 The generated electric field between the latent image portion of the main portion 10a of the photosensitive roll 10 and the developing roll 133 from the suction roll 40 (potential is −720V) to the downstream transport roll 134 (potential is −1500 V). While being in the same direction, the electric field stronger than the electric field between the latent image portion and the developing roll 133 (potential difference is 680 V) overcomes the electrostatic attraction between the magnetic carrier and is attracted to the attracting roll 40. Thereafter, the overcharged toner adsorbed on the adsorbing roll 40 is removed from the adsorbing roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred because the transfer roll 14 is not present, and is accommodated in the residue container 22. The In this way, the cause of the generation of the low-charge toner and the reverse polarity toner is reduced by removing the overcharged toner from the deteriorated toner. In addition, since the removal of the overcharged toner is performed immediately before the position where the new toner is supplied, which is the most downstream in the developer transport direction in the first storage chamber 132a of the developer storage tank 132, the low charge toner is low. Generation of charged toner and reverse polarity toner is effectively suppressed. The fourth power supply 144 corresponds to an example of the large difference generation potential applying unit referred to in the present invention.

  On the other hand, when the fifth power source 145 is connected to the upstream side transport roll 135 shown in FIG. 12, the fifth power source 145 is electrostatically attached to the magnetic carrier held on the upstream side transport roll 135, and The reverse polarity toner out of the toner transported to the region formed between the upstream side transport roll 135 (potential is 200V) and the end 10b (potential is 200V) generated between the end 10b of the photoreceptor roll 10. The electric potential is 0 V). The electric field opposite to the electric field between the latent image portion of the main portion 10a of the photosensitive roll 10 and the developing roll 133 overcomes the electrostatic attractive force between the magnetic carrier and the end portion 10b. To be adsorbed. The reverse polarity toner adsorbed on the end portion 10 b is then removed from the end portion 10 b by the cleaning member 21 of the cleaning device 20 without being transferred, and stored in the residue storage box 22. In addition, when the sixth power source 146 is connected to the upstream side transport roll 135, the region that is electrostatically attached to the magnetic carrier held by the upstream side transport roll 135 and is formed between the end portion 10 b. The low-charged toner among the toners conveyed to the photosensitive drum is generated between the end 10b and travels from the end 10b (potential is 0V) to the upstream-side transport roll 135 (potential is −200V). An electric field (potential difference is 200V) which is in the same direction as the electric field between the latent image portion of the main portion 10a of the roll 10 and the developing roll 133 but is weaker than the electric field (potential difference 300V) between the latent image portion and the developing roll 133. ) To overcome the electrostatic attraction between the magnetic carrier and be attracted to the end 10b. Thereafter, the low-charged toner adsorbed on the end portion 10 b is removed from the end portion 10 b by the cleaning member 21 of the cleaning device 20 without being transferred, and stored in the residue storage box 22. As described above, the low-charge toner and the reverse polarity toner are adsorbed by the upstream suction roll 30 and removed from the developer storage tank 132 at the uppermost stream in the developer transport direction in the first storage chamber 132 a of the developer storage tank 132. Is done. For this reason, even if low-charged toner or reverse-polar toner is generated despite the above-described removal of the overcharged toner, scattering of the low-charged toner to the outside of the developing device and adhesion of the reverse-polar toner to the background are suppressed. . That is, the removal of the overcharged toner and the removal of the lowly charged toner and the reverse polarity toner exhibit a synergistic effect. For this reason, even when a low-temperature fixing toner that is easily deteriorated as in the present embodiment is employed, the occurrence of low-charge toner and reverse-polar toner is sufficiently suppressed. In addition, the removal of the low-charge toner and the reverse polarity toner is the most upstream flow in the developer transport direction in the first storage chamber 132a of the developer storage tank 132, and between the developing roll 133 and the main portion 10a of the photoreceptor roll 10. Since it is performed at a position immediately before the toner image is formed by cooperation, a decrease in the density of the toner image and a decrease in image quality due to the toner being placed on the background are suppressed. The sixth power source 146 corresponds to an example of the small difference generation potential applying unit according to the present invention, and the fifth power source 145 corresponds to an example of the reverse electric field generation potential applying unit according to the present invention.

  Next, a ninth embodiment of the image forming apparatus of the present invention will be described.

  The difference between the ninth embodiment and the eighth embodiment is that, in the eighth embodiment, the downstream-side transport roll 134 and the developing roll 133 are separate members, whereas in the ninth embodiment, the downstream-side transport. The point that the roll 134 and the developing roll 133 are integrated, and in the eighth embodiment, the irradiation range of the laser exposure light is only the main portion 10a of the photosensitive roll 10, whereas in the ninth embodiment the photosensitive member. In addition to the main portion 10a of the roll 10 and extending to the suction roll 40, the other configurations and operations are the same, so only this difference will be described below.

  FIG. 13 is a diagram illustrating a state of irradiation of laser exposure light from a laser exposure device to a photoconductor roll and a potential of each part in the printer of the ninth embodiment.

  FIG. 13 shows a state in which the irradiation range of the laser exposure light from the laser exposure device 12 extends to the suction roll 40 in addition to the main portion 10a of the photoconductor roll 10.

  FIG. 13 shows a developer holding roll 233 in which the downstream transport roll 134 and the developing roll 133 of another member are integrated in the printer of the eighth embodiment.

  The potential of the suction roll 40 shown in FIG. 13 is -720V due to charging by the sub-charging roll 50, and then becomes -200V by irradiation with laser exposure light. Further, the potential of the developer holding roll 233 is set to −600 V by a power source (not shown), and the potentials of the other members are the same as those shown in FIG.

  Due to the above potential relationship, the overcharged toner among the toners electrostatically attached to the magnetic carrier held on the developer holding roll 233 and conveyed to the area formed with the suction roll 40 is attracted. The latent image portion of the main portion 10a of the photosensitive roll 10 and the developer holding from the suction roll 40 (potential is -200V) to the developer holding roll 233 (potential is -600V) generated between the roller 40 and the roll 40. The electric field (potential difference is 400 V) stronger than the electric field between the latent image portion and the developer holding roll 233 while being in the same direction as the electric field between the roll 233 and the electrostatic attraction with the magnetic carrier is overcome. It is adsorbed by the adsorbing roll 40. Thereafter, the overcharged toner adsorbed on the adsorbing roll 40 is removed from the adsorbing roll 40 by the cleaning member 21 of the cleaning device 20 without being transferred, and is stored in the residue storage box 22. In other words, the electrical control is simplified by integrating the downstream-side transport roll 134 and the developing roll 133. Incidentally, the adsorption of the low-charge toner and the reverse polarity toner and the formation of the toner image have already been described, and therefore will be omitted.

  In the above description, an example of a printer is shown as an embodiment of the image forming apparatus. However, the image forming apparatus referred to in the present invention is not limited to a printer, and may be a copying machine or a facsimile, for example.

  In the embodiment described above, an example of a roll-shaped photosensitive member is shown as the image carrier referred to in the present invention. However, the image carrier referred to in the present invention is not limited thereto, and may be, for example, a belt-shaped member. Good.

  In the above-described embodiment, the charging roll and the laser exposure device are shown as an example of the charging device and the exposure device according to the present invention. However, the charging device and the exposure device according to the present invention are not limited thereto, for example, a charging roll. Alternatively, a corona discharger such as a corotron or a scorotron may be used, or an array of a plurality of light emitting diodes may be used instead of a laser exposure device.

  In the above-described embodiment, an example having a roll-shaped outer shape is shown as an example of the independent member according to the present invention. However, the independent member according to the present invention is not limited to a roll-shaped one, for example, a belt-shaped one. In addition, the independent member referred to in the present invention only needs to have a surface potential independent of the surface potential of the image carrier, and may be, for example, an insulating material capable of applying a potential to the surface.

  In the above-described embodiment, the specific potential value is exemplified as the potential applied to the developing roll and the independent member according to the present invention. However, the potential according to the present invention is not limited to the illustrated value, It may be a different value, or may vary according to environmental conditions and toner status.

  In the above-described embodiment, the specific potential difference value is exemplified as the first potential difference and the second potential difference according to the present invention. However, the potential difference according to the present invention is not limited to the illustrated value, and is different from the illustrated value. It may be a value, or it may change according to environmental conditions and toner status.

  In the embodiment, the example in which the low-temperature fixing toner is used as the toner to be attached to the latent image on the surface of the image carrier according to the present invention has been described. However, the toner according to the present invention is not limited to the low-temperature fixing toner, and is conventionally known. The toner may also be used.

  Here, a manufacturing method of the above-described low-temperature fixing toner will be described.

Below, the manufacturing method of the toner employ | adopted with the printer 1 of FIG. 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 polyester resin in the toner of 5%, and a toner shape factor of about 115 will be described.
-Crystalline polyester 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 in the electrostatic charge developing toner means that the DSC curve has a clear endothermic peak in differential scanning calorimetry (DSC). It means that an endothermic peak when measured at 10 ° C./min occurs and then returns to the baseline of the DSC curve.

As the crystalline polyester resin, specifically, an aliphatic crystalline polyester resin having an appropriate melting temperature and an alkyl group having 6 or more carbon atoms is more preferable. The crystalline 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 a polyhydric alcohol. For example, dodecenyl succinate Although an acid etc. can be used, it is not restricted to this.
Examples of the polyvalent carboxylic acids used in the production of the resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, Aromatic oxycarboxylic acids such as p-oxybenzoic acid and p- (hydroxyethoxy) benzoic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid and other aliphatic dicarboxylic acids Unsaturated aliphatics such as acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, dimer acid, trimer acid, hydrogenated dimer acid, cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid And alicyclic dicarboxylic acids, etc. As may be used other trimellitic acid, trimesic acid, and the like trivalent or higher polyvalent carboxylic acids such as pyromellitic acid.

  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, Ring opening of lactones such as neopentyl glycol, diethylene glycol, dipropylene glycol, dimethylol heptane, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ε-caprolactone Examples include aliphatic diols such as lactone-based polyester polyols obtained by polymerization, triols such as trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol, and tetraols.

  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, ortho-xylene glycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, ethylene oxide adduct of bisphenol A and Examples thereof include 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, stearyl Monocarboxylic acids such as acids 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 polyester 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. They are manufactured using different types of monomers.

  The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction is carried out while reducing the pressure in the reaction system as necessary to remove 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. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound: Phosphorous acid compound, phosphoric acid compound, amine compound and the like.

  The melting temperature of the crystalline polyester resin is preferably 50 to 100 ° C, more preferably 60 to 100 ° C. If the melting temperature is lower than 50 ° C., the toner storage stability and the storage stability of the toner image after fixing may become a problem. On the other hand, if the melting temperature is higher than 100 ° C., sufficient low-temperature fixing can be obtained as compared with conventional toners. There may not be.

  The crystalline polyester resin may show a plurality of melting peaks, but here the maximum peak is taken as the melting temperature.

  Furthermore, for example, DSC-7 manufactured by Perkin Elmer can be used for measurement of the resin melting temperature. For the temperature correction of the detection part of this apparatus, the glass transition temperature of the resin can be measured in the same manner using the melting temperature of indium and zinc.

  The crystalline polyester resin used in this toner has a weight average molecular weight (Mw) of 8,000 to 35,000 as determined by gel permeation chromatography (GPC) method of tetrahydrofuran (THF) soluble content. , 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 be generated. 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 was measured with a THF solvent using a TSO gel GPC / HLC-9120, a Tosoh column “TSKgel SuperHM-M” (15 cm), and a monodisperse polystyrene standard sample. The molecular weight was calculated using the prepared molecular weight calibration curve. It measured similarly also in the measurement of the amorphous polyester resin mentioned later.

  The toner preferably has a melting temperature (mp) measured in accordance with ASTM D3418-8 of crystalline polyester resin of 50 to 100 ° C. When the melting temperature is less than 50 ° C., the heat security 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 the crystalline polyester resin (mg of KOH necessary for neutralizing 1 g of resin) is controlled to 5 to 50 mg KOH / g. When the acid value is less than 5 mgKOH / g, the crystalline polyester resin particles form aggregates and it becomes difficult to form a structure with the release agent, and the crystalline polyester resin particles are independent in the toner. Or may grow to a large extent and be exposed on the toner surface, which is not preferable from the viewpoint of toner fluidity and 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 polyester resin can be produced by subjecting the polyhydric alcohol and polyvalent carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

The glass transition temperature of the amorphous polyester resin used in this toner is ASTM
When determined in accordance with D3418-8, it is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, and further 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.

  The softening point of the amorphous polyester resin used for this toner is preferably in the range of 60 to 90 ° C. 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 this toner is tetrahydrofuran (THF).
The weight average molecular weight (Mw) is 20,000 to 50,000, preferably 25,000 to 50,000 by molecular weight measurement by gel permeation chromatography (GPC) method of soluble matter. 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. When the acid value is less than 10 mgKOH / g, the particle size growth of the aggregates during the production of the toner is accelerated, and there may be a problem that the particle size distribution of the resulting toner is expanded. In addition, when the acid value exceeds 50 mgKOH / g, the difference between the acid value of the crystalline polyester resin and the release agent increases, and therefore, only the aggregation with the crystalline polyester resin and the release agent may proceed. There is a problem that the fixability changes between toner particles. The acid value of the amorphous polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester by the blending ratio and reaction rate of the raw material polycarboxylic 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 this toner, the weight ratio of the crystalline polyester resin to the amorphous polyester resin is 5/95 to 40/60, and when the ratio of the amorphous polyester resin is less than 60%, good fixing characteristics can be obtained. The phase separation structure in the fixed image becomes non-uniform, and the strength of the fixed image, particularly the scratching strength, may be reduced, which may cause a problem of being easily damaged. On the other hand, if it exceeds 95%, sharp melt properties derived from the crystalline polyester resin may not be obtained, and plasticity may occur. To ensure good low-temperature fixability, toner blocking resistance and image storage stability are improved. You may not be able to keep it.

  The preparation of the crystalline polyester resin and the amorphous polyester 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 used in this toner include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones which show a softening point upon heating; oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide Fatty acid amides such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil and other plant waxes; beeswax and other animal waxes; montan wax, ozokerite, ceresin wax, microcrystalline wax, fisher Minerals such as Tropsch wax, petroleum wax, ester waxes of higher fatty acids such as stearyl stearate and behenyl behenate and higher alcohols; butyl stearate, propyl oleate, glycerate monostearate Ester waxes of higher fatty acids such as glycerides, distearic glycerides, pentaerythritol tetrabehenate and unitary or polyhydric lower alcohols; diethylene glycol monostearate, dipropylene glycol distearate, distearic diglyceride, tetrastearic triglyceride, etc. Ester waxes composed of higher fatty acids and polyhydric alcohol multimers; sorbitan higher fatty acid ester waxes such as sorbitan monostearate; 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. Further, in the present embodiment, those having a melting temperature of 40 ° C. to 120 ° C. are used among these, and in order to meet the recent demand for low temperature fixability as energy saving measures, in particular, 50 ° C. to The thing of 100 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 still more preferably in the range of 5 to 15% by weight with respect to the total amount of the toner. % Range. When the addition amount is less than 0.5% by weight, there is no effect of adding a release agent. When the addition amount exceeds 30% by weight, the chargeability is likely to be affected, or the toner is easily destroyed inside the developing device, and the release agent is released. In some cases, the mold agent is spent on the carrier, and the charge is likely to decrease.

  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 diameter exceeds 0.5 μm, the toner is easily exposed to the toner surface, and the powder fluidity of the toner is deteriorated and filming on the image holding member and the developing member is easily performed. 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 machine 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. The wax dispersion used for this toner is prepared by a known dispersion method 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 particle size and content as described can be satisfied.
-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 toner manufacturing method 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. Specific examples of the colorant include carbon blacks such as furnace black, channel black, acetylene black, and thermal black; inorganic pigments such as bengara, aniline black, bitumen, titanium oxide, and magnetic powder; fast yellow, monoazo Azo pigments such as yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine (3B, 6B, etc.), para brown, etc .; phthalocyanine pigments such as copper phthalocyanine, metal-free phthalocyanine; flavantron yellow, dibromoanthrone orange, perylene red, quinacridone And condensed polycyclic pigments such as red and dioxazine violet.

  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, Rhodamine B Lake, Lake Red C, Rose Various pigments such as 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 dyes, triphenylmethane dyes, diphenylmethane dyes, thiazole type, various dyes such as xanthene; 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 for this toner is, for example, a known dispersion method such as a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a nanomizer, a microfluidizer, an optimizer, or a high-pressure type dispersing machine such as a gorin. As long as it can satisfy the particle size and content as described above, it may be produced by any method or condition.
<Other ingredients>
Other components that can be used in the toner are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include various known additives such as inorganic particles, organic particles, charge control agents, and release agents. It is done.

  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 volume average particle diameter of the toner is 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, a developer for developing an electrostatic latent image (hereinafter also referred to as “developer”) will be described.

  There is no restriction | limiting in particular except a developer containing said toner, According to the objective, an appropriate component composition can be taken. This developer 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; Vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; Vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl keto Homopolymers such as vinyl ketones such as ethylene; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers comprising two or more types of monomers Furthermore, silicone resins containing methyl silicone, methyl phenyl silicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. 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, 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 toner will be described more specifically with reference to examples. In the following description, “part” means “part by mass” unless otherwise specified.
(Measurement method of loss modulus)
The loss elastic modulus was 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.
(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 the toner particles on the 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.
This shape factor is obtained by taking a photograph in which toner particles are magnified 2000 times with a scanning electron microscope, and then analyzing a photographic image using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. Was measured.
At this time, 100 toner particles were used, and the shape factor of the toner was measured by the above calculation formula.
(Measuring method of particle size and particle size distribution)
This toner particle size and particle size distribution measurement will be described. When the particles to be measured were 2 μm or more, Coulter Multisizer II type (manufactured by Beckman Coulter, Inc.) was used as the measuring apparatus, and ISOTON-II (manufactured by Beckman-Coulter, Inc.) 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 particle size of the toner 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 of the toner used 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.
-Adjustment of crystalline polyester resin-
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 reacted for 7 hours, followed by cooling to obtain a crystalline polyester resin. The crystalline polyester resin had a weight average molecular weight of 17,000.
-Production of amorphous polyester 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 polyester resin. The amorphous polyester resin had a weight molecular weight of 16,500.
-Preparation of crystalline polyester / amorphous polyester mixed resin dispersion-
To a three-necked flask, add 5 parts by mass of the above crystalline resin, 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, and heat to 60 ° C. while stirring. Is dissolved, and 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 after removing the solvent, the solid content concentration was adjusted to 25% to obtain a crystalline polyester / amorphous polyester mixed resin dispersion. It was.
-Preparation of release agent dispersion-
Paraffin wax (Nippon Seiwa Co., Ltd .: HNP9, melting temperature 77 ° C.): 60 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 4 parts by mass 200 parts 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), and then dispersed with a Menton Gorin high-pressure homogenizer (Gorin). A release agent dispersion was prepared by dispersing a release agent having an average 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-
-Crystalline polyester / amorphous polyester mixed resin dispersion: 720 parts by mass-Colorant dispersion: 50 parts by mass-Release agent dispersion: 70 parts by mass-Cationic surfactant-(Kao Co., Ltd .: SANISOL B50): 1.5 parts by mass The above components are housed in a round stainless steel flask, and 0.1 N sulfuric acid is added to adjust the pH to 3.8. As a solution, 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 size 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. while maintaining stirring and maintained 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 had a volume average particle size of 6.1 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-
About the above toner base particles, 1.2 parts by mass of commercially available fumed silica RX50 (manufactured by Nippon Aerosil Co., Ltd.) is added as an external additive to 100 parts by mass of each toner base particle, and the mixture is mixed with a Henschel mixer for electrostatic charge. An image developing toner was 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.

DESCRIPTION OF SYMBOLS 1 Printer 10 Photoconductor 10a Main part 10b End part 11 Charging roll 12 Laser exposure device 13 Developing device 130 Toner supply part 131 Stirring conveyance member 132 Developer storage tank 133 Developing roll 134 Downstream conveyance roll 135 Upstream conveyance roll 138 Changeover switch DESCRIPTION OF SYMBOLS 14 Transfer roll 20 Cleaning apparatus 21 Cleaning member 22 Residue storage box 233 Developer holding roll 40 Adsorption roll 41 Main part side adsorption part 42 Non-main part side adsorption part 50 Subcharging roll

Claims (16)

An image carrier that forms an image on the surface and holds the image;
A charger for charging the surface of the image carrier;
An exposure unit that forms an electrostatic latent image on the surface by exposing the surface of the image carrier charged by the charger;
A developing unit containing a developer containing the toner, which forms a toner image by attaching toner to a latent image formed on the surface of the image carrier;
The charger is configured to charge the surface of the image carrier excluding a predetermined end on the image carrier;
An independent member arranged on the opposite side of the end with the image carrier, the surface potential being independent of the surface potential of the image carrier;
An independent member charger for charging the surface of the independent member;
The developer is
Adjacent to both the image carrier and the independent member, and having a potential difference between the image carrier and the independent member, holding the developer on the surface and rotating the developer to hold the image A developing roll that conveys the developer to an area facing the body and the independent member, wherein the developer is conveyed to a developing area facing the other portion of the area excluding the end on the image carrier. The image carrier is between the developing unit having a main potential difference and the independent member that conveys the developer to the first non-developing region facing the independent member of the region. A first non-developing portion having a first potential difference different from the main potential difference, and the image carrier for transporting the developer to a second non-developing region facing the end of the region; A developing roll having a second non-developing portion having a second potential difference different from the main potential difference between
Adjacent to the developing roll and extending along the rotating shaft of the developing roll, containing the developer inside and supplying the developer to the developing roll, stirring the contained developer on the rotating shaft A first accommodating portion that conveys in a first direction along;
The developer is accommodated in the interior, provided with a moving port for moving the developer between the first accommodating portion and at both ends, which is adjacent to the first accommodating portion and extends side by side with the first accommodating portion. A second storage unit that is supplied with toner and conveys the developer and the toner in a second direction opposite to the first direction while stirring and mixing the developer;
An image forming apparatus comprising: a toner supply unit that supplies toner to the second storage unit through a toner supply port. The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus has a potential difference larger than the main potential difference generated between the image holding member and the image carrier. The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. A potential difference larger than the main potential difference generated between the image carrier and the image carrier;
From the main potential difference, the first non-developing part generates an electric field in the same direction as the main electric field as the first potential difference between the first non-developing part and the independent member body. 3. The image forming apparatus according to claim 1, wherein the image forming apparatus has a small potential difference. The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. A potential difference larger than the main potential difference generated between the image carrier and the image carrier;
The first non-developing portion has a potential difference that generates an electric field opposite to the direction of the main electric field between the first non-developing portion and the independent member as the first potential difference. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided. An exposure unit for an independent member that forms a potential distribution on the surface of the independent member;
The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
The second non-development unit generates an electric field in the same direction as the main electric field generated between the development unit and the image carrier as the second potential difference. A potential difference larger than the main potential difference generated between the image carrier and the image carrier;
From the main potential difference, the first non-developing part generates an electric field in the same direction as the main electric field as the first potential difference between the first non-developing part and the image carrier. The potential distribution simultaneously has both a small potential difference and a potential difference that generates an electric field opposite to the direction of the main electric field between the first non-development portion and the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The developing roller is configured such that the developing unit and the second non-developing unit are separated from each other, and different potentials are applied to the developing unit and the second non-developing unit. Having a second potential difference,
The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
By applying a potential to the second non-developing portion, a potential difference larger than the main potential difference between the second non-developing portion and the image carrier, and the image carrier and the developing portion The image forming apparatus according to claim 1, further comprising a large difference generation potential applying unit that generates an electric field having the same direction as a main electric field generated between the two. In the developing roll, the developing unit and the first non-developing unit are separated from each other, and different potentials are applied to the developing unit and the first non-developing unit, so that the main potential difference and the first non-developing unit are applied. Having a potential difference,
The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
By applying a potential to the first non-development portion, a potential difference smaller than the main potential difference and an electric field in the same direction as the main electric field direction are provided between the first non-development portion and the independent member. The image forming apparatus according to claim 1, further comprising a small difference generation potential applying unit that generates In the developing roll, the developing unit and the first non-developing unit are separated from each other, and different potentials are applied to the developing unit and the first non-developing unit, so that the main potential difference and the first non-developing unit are applied. Having a potential difference,
The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
Applying a potential to the first non-developing portion, applying a reverse electric field generation potential that generates an electric field in a direction opposite to the direction of the main electric field between the first non-developing portion and the independent member. The image forming apparatus according to claim 1, further comprising: a first section. In the developing roll, the developing unit and the first non-developing unit are separated from each other, and different potentials are applied to the developing unit and the first non-developing unit, so that the main potential difference and the first non-developing unit are applied. Having a potential difference,
The first storage unit conveys the developer with the direction from the first non-developing unit side to the second non-developing unit side as the first direction,
By applying a first potential to the first non-developed portion, a potential difference smaller than the main potential difference and the direction of the main electric field are the same between the first non-developed portion and the independent member. And applying a second potential to the first non-developing part, the small non-developing part between the first non-developing part and the independent member. A potential applying unit that serves as a reverse electric field generation potential applying unit that generates an electric field that is opposite to the direction of the main electric field and that can freely switch between the first electric potential and the second electric potential is provided. The image forming apparatus according to any one of claims 1 to 4, 6, 7, and 8. The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
The first non-developing part generates an electric field in the same direction as the main electric field generated between the developing part and the image carrier as the first potential difference. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus has a potential difference larger than the main potential difference generated between the image holding member and the image carrier. The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
The first non-developing part generates an electric field in the same direction as the main electric field generated between the developing part and the image carrier as the first potential difference. A potential difference larger than the main potential difference generated between the image carrier and the image carrier;
The second non-development section generates an electric field in the same direction as the main electric field as the second potential difference between the second non-development section and the independent member. The image forming apparatus according to claim 1, wherein the image forming apparatus has a small potential difference. The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
The first non-developing part generates an electric field in the same direction as the main electric field generated between the developing part and the image carrier as the first potential difference. A potential difference larger than the main potential difference generated between the image carrier and the image carrier;
The second non-developing portion has a potential difference that causes an electric field opposite to the direction of the main electric field to be generated between the second non-developing portion and the independent member as the second potential difference. The image forming apparatus according to claim 1, wherein the image forming apparatus is one. In the developing roll, the developing unit and the first non-developing unit are separated from each other, and different potentials are applied to the developing unit and the first non-developing unit, so that the main potential difference and the first non-developing unit are Having a first potential difference,
The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
By applying a potential to the first non-developing part, a potential difference larger than the main potential difference between the first non-developing part and the image carrier, and the image carrier and the developing part The image forming apparatus according to claim 1, further comprising a large difference generation potential applying unit that generates an electric field in the same direction as the direction of the main electric field generated between the two. apparatus. In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, so that the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
A small difference generating potential applying unit that generates a potential difference smaller than the main potential difference and an electric field in the same direction as the main electric field is provided between the independent member and the second non-developing unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, so that the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
11. A reverse electric field generating potential applying unit that generates an electric field opposite to the direction of the main electric field between the independent member and the second non-developing unit. The image forming apparatus according to any one of 11, 12, 13, and 14. In the developing roll, the developing portion and the second non-developing portion are separated from each other, and different potentials are applied to the developing portion and the second non-developing portion, so that the main potential difference and the second non-developing portion are applied. Having a potential difference,
The first container transports the developer with the first direction as the direction from the second non-developing part side to the first non-developing part side,
A potential difference applying unit configured to apply a potential difference between the independent member and the second non-developing unit, wherein the developing unit and the image carrier are disposed between the independent member and the second non-developing unit; A potential difference in which the potential difference is smaller than the potential difference between them, and the polarity of the relative potential of the independent member with respect to the second non-development portion is the same as the polarity of the relative potential of the image carrier with respect to the development portion, and A potential difference applying section that switches and applies a potential difference in which the polarity of the relative potential of the independent member with respect to the second non-developing section is opposite to the polarity of the relative potential of the image holding body with respect to the developing section. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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