JP2016218410A - Image forming apparatus, process cartridge, image forming method, and method for cleaning toner replenishment path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus for suppressing the occurrence of an image defect.SOLUTION: The image forming apparatus includes an image holder, electrifying means for electrifying the surface of the image holder, electrostatic charge image forming means for forming an electrostatic charge image on the surface of the electrified image holder, developing means for storing an electrostatic charge image developer including toner and developing the electrostatic charge image formed on the surface of the image holder as a toner image by the electrostatic charge image developer, transfer means for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, fixing means for fixing the toner image transferred to the surface of the recording medium, a replenishment toner storage part for storing replenishment toner replenished to the developing means, a toner replenishment path connecting the replenishment toner storage part and the developing means and including toner conveyance means conveying the replenishment toner to the developing means inside, and granular composition supply means for supplying a granular composition containing 80 mass% or more of magnetic particles to the toner replenishment path.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus, a process cartridge, an image forming method, and a toner replenishment path cleaning method.

  As an electrophotographic image forming apparatus, for example, Patent Document 1 contains a developer having a toner and a carrier, a developing unit that develops a latent image formed on an image carrier, and a transfer unit. A cleaning unit that collects untransferred toner adhering to the passed image holding member, a supply unit that supplies a new carrier to the cleaning unit, untransferred toner collected by the cleaning unit, and the supply unit that is supplied from the supply unit There is disclosed an image forming apparatus including a conveyance unit that mixes a new carrier and conveys the new carrier to the developing unit.

JP 2005-326708 A

  It is an object of the present invention to provide an image forming apparatus that suppresses the occurrence of image defects as compared with a case where there is no means for supplying a granular composition containing 80% by mass or more of magnetic particles to a toner supply path.

  Specific means for solving the above-described problems include the following modes.

The invention according to claim 1
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A granular composition supply means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path;
An image forming apparatus comprising:

The invention according to claim 2
The image forming apparatus according to claim 1, wherein the magnetic particles are a carrier for an electrostatic charge image developer.

The invention according to claim 3
The image forming apparatus according to claim 1, wherein a volume average particle diameter of the magnetic particles is 15 μm or more and 80 μm or less.

The invention according to claim 4
The image forming apparatus according to claim 1, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less.

The invention according to claim 5
Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A granular composition supply means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path;
And a process cartridge that is detachably attached to the image forming apparatus.

The invention according to claim 6
The process cartridge according to claim 5, wherein the magnetic particles are a carrier for an electrostatic charge image developer.

The invention according to claim 7 provides:
The process cartridge according to claim 5 or 6, wherein a volume average particle size of the magnetic particles is 15 µm or more and 80 µm or less.

The invention according to claim 8 provides:
The process cartridge according to claim 5, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less.

The invention according to claim 9 is:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image by a developing unit containing an electrostatic charge image developer containing toner;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
The replenishing toner is supplied to the developing means by the toner transporting means in the toner replenishing path through the toner replenishing path connecting the replenishing toner containing part and the developing means from the replenishing toner containing section for storing the replenishing toner. A toner replenishment process for replenishing
A granular composition supplying step of supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path and passing the granular composition;
An image forming method comprising:

The invention according to claim 10 is:
The image forming method according to claim 9, wherein the magnetic particles are a carrier for an electrostatic charge image developer.

The invention according to claim 11 is:
The image forming method according to claim 9 or 10, wherein a volume average particle diameter of the magnetic particles is 15 µm or more and 80 µm or less.

The invention according to claim 12
The image forming method according to claim 9, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less.

The invention according to claim 13 is:
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A toner replenishment path cleaning method performed in an image forming apparatus comprising:
A method for cleaning a toner replenishment path, comprising: supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path.

The invention according to claim 14 is:
The toner replenishment path cleaning method according to claim 13, wherein the magnetic particles are a carrier for an electrostatic charge image developer.

The invention according to claim 15 is:
The toner replenishment path cleaning method according to claim 13 or 14, wherein a volume average particle diameter of the magnetic particles is 15 µm or more and 80 µm or less.

The invention according to claim 16 provides:
The toner replenishment path cleaning method according to any one of claims 13 to 15, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less.

According to the first aspect of the present invention, there is provided an image forming apparatus that suppresses the occurrence of image defects as compared with a case where there is no means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path. The
According to the second aspect of the present invention, there is provided an image forming apparatus in which the occurrence of image defects is further suppressed as compared with the case where the magnetic particles are not an electrostatic charge image developer carrier.
According to the third aspect of the present invention, there is provided an image forming apparatus in which the occurrence of image defects is further suppressed as compared with the case where the volume average particle diameter of the magnetic particles is not within the above range.
According to the invention which concerns on Claim 4, compared with the case where the bulk density of a magnetic particle is not the said range, the image forming apparatus which suppresses generation | occurrence | production of an image defect more is provided.

According to the fifth aspect of the present invention, there is provided a process cartridge that suppresses the occurrence of image defects as compared with a case where there is no means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path. .
According to the sixth aspect of the present invention, there is provided a process cartridge in which the occurrence of image defects is further suppressed as compared with the case where the magnetic particles are not an electrostatic charge image developer carrier.
According to the invention which concerns on Claim 7, compared with the case where the volume average particle diameter of a magnetic particle is not the said range, the process cartridge which suppresses generation | occurrence | production of an image defect more is provided.
According to the eighth aspect of the present invention, there is provided a process cartridge that further suppresses the occurrence of image defects as compared with the case where the bulk density of the magnetic particles is not within the above range.

According to the ninth aspect of the present invention, there is provided an image forming method that suppresses the occurrence of image defects as compared with a case where there is no step of supplying and passing a granular composition containing 80% by mass or more of magnetic particles to the toner supply path. Provided.
According to the tenth aspect of the present invention, there is provided an image forming method in which the occurrence of image defects is further suppressed as compared with the case where the magnetic particles are not an electrostatic charge image developer carrier.
According to the invention concerning Claim 11, compared with the case where the volume average particle diameter of a magnetic particle is not the said range, the image forming method which suppresses generation | occurrence | production of an image defect more is provided.
According to the invention which concerns on Claim 12, compared with the case where the bulk density of a magnetic particle is not the said range, the image formation method which suppresses generation | occurrence | production of an image defect more is provided.

According to the thirteenth aspect of the present invention, there is provided a toner replenishment path cleaning method that suppresses the occurrence of image defects as compared with a case where the granular composition supplied to and passed through the toner replenishment path does not contain 80% by mass or more of magnetic particles. Provided.
According to the fourteenth aspect of the present invention, there is provided a method for cleaning a toner replenishment path that further suppresses the occurrence of image defects as compared with the case where magnetic particles are not a carrier for an electrostatic charge image developer.
According to the fifteenth aspect of the present invention, there is provided a toner replenishment path cleaning method that further suppresses the occurrence of image defects as compared with the case where the volume average particle diameter of the magnetic particles is not within the above range.
According to the sixteenth aspect of the present invention, there is provided a toner replenishment path cleaning method that further suppresses the occurrence of image defects as compared with the case where the bulk density of the magnetic particles is not within the above range.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a schematic configuration diagram illustrating an example of an image holding member, a developing unit, a replenishing toner container, a toner replenishing path, and a granular composition supplying unit that are included in the image forming apparatus according to the present embodiment. FIG. 2 is a schematic configuration diagram illustrating an example of an image holding member, a developing unit, a replenishing toner container, a toner replenishing path, and a granular composition supplying unit that are included in the image forming apparatus according to the present embodiment.

  Embodiments of the invention will be described below. These descriptions and examples illustrate embodiments and do not limit the scope of the invention.

  In the present specification, the “electrostatic image developer” is also simply referred to as “developer”.

<Image Forming Apparatus, Image Forming Method, Cleaning Method for Toner Supply Path>
The image forming apparatus according to the present embodiment is an electrophotographic image forming apparatus, and connects a replenishment toner storage unit that stores replenishment toner to be replenished to the development unit, a replenishment toner storage unit, and the development unit. And a toner replenishing path having toner conveying means for conveying the replenishing toner to the developing means, and a granular composition supplying means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishing path.

  The image forming method according to the present embodiment is an electrophotographic image forming method in which a toner is supplied from a replenishing toner accommodating portion that accommodates a replenishing toner through a toner replenishing path that connects the replenishing toner accommodating portion and the developing means. A toner replenishing step of replenishing the developing means with toner for replenishment by toner conveying means in the replenishment path; a granular composition supplying step for supplying and passing a granular composition containing 80% by mass or more of magnetic particles to the toner replenishing path; Have

  The toner replenishment path cleaning method according to the present embodiment is an electrophotographic image forming apparatus, which includes a replenishment toner accommodating portion for accommodating a replenishing toner to be replenished to a developing unit, a replenishing toner accommodating portion, and a development. And a toner replenishment path having toner conveying means for conveying replenishment toner to the developing means. The toner replenishment path includes a granular composition containing 80% by mass or more of magnetic particles. A particulate composition supplying step for supplying and passing the material.

  According to the image forming apparatus, the image forming method, and the toner replenishment path cleaning method according to the present embodiment, occurrence of image defects is suppressed. The following mechanism can be considered as the reason.

  In an electrophotographic image forming apparatus, the toner contained in the developer in the developing unit is consumed and reduced as image formation is repeated, so that the toner concentration of the developer in the developing unit is within a predetermined range. In addition, replenishment toner is replenished to the developing means. The replenishment toner is replenished to the developing means from a replenishment toner container such as a toner cartridge through a toner replenishment path. The toner replenishing path is provided with toner conveying means such as an auger screw, an auger coil, and a spring coil, and the toner for replenishment is conveyed through the toner replenishing path by the operation of the toner conveying means.

  However, when image formation is repeated in the above-described image forming apparatus, the image density may decrease even though the replenishment toner is supplied to the developing unit. In addition, color streaks may appear in the image. In particular, these image defects are likely to occur when the image forming apparatus is placed under high temperature and high humidity (for example, an environment having a temperature of 28 ° C. or higher and a relative humidity of 80% or higher).

  As a cause of the occurrence of the estimated image defect, there is an event that the replenishing toner adheres to the toner conveying means and the inner wall of the toner replenishing path or aggregates in the toner replenishing path. When the above event occurs, the amount of toner replenished to the developing unit decreases, the toner concentration of the developer in the developing unit becomes lower than a predetermined range, and the image density decreases. In addition, toner aggregates generated in the toner replenishment path are mixed into the developer in the developing means, and color streaks are generated. In addition, if the toner concentration of the developer in the developing unit is lower than the predetermined range, the supply of the replenishing toner is continued, so that the above events accumulate in the toner replenishment path.

  This embodiment solves the above problem by supplying a granular composition containing 80% by mass or more of magnetic particles (hereinafter also referred to as “specific granular composition”) to the toner supply path and passing through the toner supply path. By passing the specific granular composition through the toner supply path, the toner adhering to the toner conveying means and the inner wall of the toner supply path is removed, and the toner aggregates present in the toner supply path are crushed. . As a result, the amount of toner replenished to the developing unit is recovered, the toner density of the developer in the developing unit is maintained within a predetermined range, and a decrease in image density is suppressed. Further, the toner aggregates in the toner replenishment path are crushed and become granular particles having the same particle size as the original toner, so that the generation of color streaks is suppressed.

  In the present embodiment, the specific granular composition contains 80% by mass or more of magnetic particles. The magnetic particles have a specific gravity higher than that of the toner, and have the ability to remove toner adhering to the toner replenishment path and to crush toner aggregates in the toner replenishment path. Further, magnetic particles are conventionally used as a carrier for charging toner, and even when mixed with a developer in the developing means, the magnetic particles have little influence on the image. The specific granular composition can reliably clean the toner replenishment path by containing 80% by mass or more of magnetic particles. A granular composition having a magnetic particle content of less than 80% by mass cannot sufficiently remove the toner adhering to the toner supply path and crush the toner aggregate in the toner supply path.

  Hereinafter, the replenishment toner storage unit, the toner replenishment path, and the granular composition supply unit included in the image forming apparatus according to the present embodiment will be specifically described.

  The replenishment toner container may be a container fixed to the image forming apparatus or a toner cartridge that is detachable from the image forming apparatus. In the replenishment toner accommodating portion, only replenishment toner may be accommodated, or a replenishment developer including the replenishment toner and the carrier may be accommodated. The replenishment developer contains toner as a main component, and the carrier concentration in the replenishment developer is usually 30% by mass or less, and preferably 20% by mass or less.

  The toner replenishment path that connects the replenishing toner container and the developing means is, for example, a resin tube, and includes toner conveying means such as an auger screw, an auger coil, and a spring coil inside the tube.

  The granular composition supply means is means for supplying the specific granular composition to the toner replenishment path. Specific examples include the following means (i) and means (ii).

  Means (i): a cartridge that contains the specific granular composition and is detachable from the replenishing toner storage section, and is mounted on the replenishing toner storage section and supplies the specific granular composition to the toner replenishment path.

  The cartridge (referred to as “granular composition cartridge”) in the means (i) is replaced with a toner cartridge and mounted in the replenishment toner storage portion. For example, the granular composition cartridge is provided outside the image forming apparatus, or is provided near the toner cartridge inside the image forming apparatus. The granular composition cartridge and the toner cartridge can be replaced manually or automatically. The granular composition cartridge contains a specific granular composition for one time or a plurality of times supplied to the toner supply path. All or a part of the stored specific granular composition is supplied to the toner supply path from the granular composition cartridge mounted in the replenishing toner storage unit.

  Means (ii): a particulate composition containing portion that contains the specific particulate composition, and a particulate composition supply passage that connects the particulate composition containing portion and the toner replenishment passage, and the specific particulate composition through the particulate composition supply passage Means for supplying the toner to the toner supply path.

  The granular composition container in the means (ii) is provided separately from the replenishment toner container. The granular composition container may be a container fixed to the image forming apparatus or a cartridge detachable from the image forming apparatus. The granular composition supply path is, for example, a resin tube, and preferably includes a granular composition conveying means such as an auger screw, an auger coil, or a spring coil inside the tube. The specific granular composition is supplied from the granular composition container to the toner replenishment path through the granular composition supply path. The granular composition supply path may be connected anywhere in the toner replenishment path, but the connecting portion between the granular composition supply path and the toner replenishment path is preferably as upstream as possible in the toner replenishment path.

  Hereinafter, the toner replenishing step and the granular composition supplying step included in the image forming method according to the present embodiment will be specifically described.

  The toner replenishing step is a step of replenishing the developing means with replenishment toner. The toner contained in the developer in the developing unit is reduced by repeating image formation. However, the replenishing toner is developed by the toner replenishing step so that the toner density of the developer in the developing unit is within a predetermined range. Will be replenished. In the toner replenishing step, the replenishing toner is transported to the developing means through the toner replenishing path by the toner transporting means in the toner replenishing path and replenished to the developing means. The toner replenishing step may be a step of replenishing only the replenishing toner, or a step of replenishing a replenishing developer including a replenishing toner and a carrier.

  The granular composition supply step is a step performed for the purpose of cleaning the toner replenishment path with the specific granular composition, and is a step for supplying and passing the specific granular composition to the toner replenishment path. In the granular composition supplying step, the toner adhering to the toner conveying means and the inner wall of the toner replenishing path is removed by passing the specific granular composition through the toner replenishing path, and the toner present in the toner replenishing path Aggregates are broken up. The specific granular composition that has passed through the toner supply path enters the developing means.

  The amount of the specific granular composition supplied to the toner supply path may be set according to the thickness and length of the toner supply path. From the viewpoint of ensuring that the toner replenishment path is reliably cleaned and the toner concentration of the developer in the developing unit is not greatly changed, the supply amount of the specific granular composition is the amount of the developer in the developing unit. 1 mass% or more and 10 mass% or less are preferable. Specifically, the amount of the specific granular composition supplied to the toner supply path is preferably 5 g or more, more preferably 10 g or more from the viewpoint of reliably cleaning the toner supply path, and the amount of the developer in the developing unit. From the viewpoint of not greatly changing the toner concentration, 20 g or less is preferable, and 15 g or less is more preferable.

  Supplying the specific granular composition to the toner supply path is performed by, for example, the means (i) or the means (ii). In addition, the supply of the specific granular composition to the toner supply path is performed, for example, by the user of the image forming apparatus throwing the specific granular composition into the upstream portion of the toner supply path. In this case, the image forming apparatus may not include the granular composition supply unit such as the unit (i) or the unit (ii).

When said means (i) is applied, a granular composition supply process is implemented by the following operation, for example.
Image formation is stopped in response to a decrease in the toner concentration of the developer in the developing means, and the toner cartridge is replaced with a granular composition cartridge. By this replacement, the granular composition cartridge is connected to the inlet of the toner supply path. Subsequently, all or a part (for example, 5 g to 20 g) of the stored specific granular composition is removed from the granular composition cartridge connected to the inlet of the toner replenishment path, for example, by free fall or in the toner replenishment path The toner is moved to the upstream portion of the toner supply path by the operation of the conveying means. Thereafter, the granular composition cartridge is replaced with a toner cartridge. Thereafter, the toner conveying means provided in the toner replenishing path is activated (for example, the toner conveying means is activated by starting image formation), and the specific granular composition in the upstream portion of the toner replenishing path is replenished with toner. Let the road pass.

When said means (ii) is applied, a granular composition supply process is implemented by the following operation, for example.
Image formation is stopped in response to a decrease in the toner concentration of the developer in the developing means. Next, the conveying means provided in the granular composition supply path is operated, and the specific granular composition is conveyed from the granular composition container to the toner supply path through the granular composition supply path. At this time, for example, the conveying means is operated until 5 g to 20 g of the specific granular composition enters the toner supply path, and then stopped. Thereafter, the toner conveying means provided in the toner replenishing path is operated (for example, the toner conveying means is operated by starting image formation), and thereby the specific granular composition is passed through the toner replenishing path.

When the user of the image forming apparatus puts the specific granular composition into the upstream portion of the toner replenishment path, the granular composition supply process is performed by the following operation, for example.
Image formation is stopped in response to a decrease in the toner concentration of the developer in the developing means. Next, the toner cartridge is removed, and 5 g to 20 g of the specific granular composition is introduced into the upstream portion of the toner supply path, and the toner cartridge is mounted again. Thereafter, the toner conveying means provided in the toner replenishing path is activated (for example, the toner conveying means is activated by starting image formation), and the specific granular composition in the upstream portion of the toner replenishing path is replenished with toner. Let the road pass.

  Hereinafter, the cleaning method for the toner supply path according to the present embodiment will be described in detail.

  The toner replenishment path cleaning method according to the present embodiment is applied to an electrophotographic image forming apparatus including a replenishment toner container and a toner replenishment path.

  Specifically, the image forming apparatus to which the toner replenishment path cleaning method according to the present embodiment is applied includes an image carrier, a charging unit that charges the surface of the image carrier, and a surface of the charged image carrier. An electrostatic charge image forming means for forming an electrostatic charge image and an electrostatic charge image developer containing toner are accommodated, and the electrostatic charge image formed on the surface of the image carrier is developed as a toner image by the electrostatic charge image developer. The developing means, a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of the recording medium, a fixing means for fixing the toner image transferred on the surface of the recording medium, and the developing means are replenished. A replenishment toner accommodating portion that accommodates the replenishing toner; a toner replenishing path that connects the replenishing toner accommodating portion and the developing unit, and includes a toner conveying unit that conveys the replenishing toner to the developing unit;

  In the image forming apparatus to which the toner replenishment path cleaning method according to the present embodiment is applied, an image holding member, a charging unit, an electrostatic charge image forming unit, a developing unit, a transfer unit, a fixing unit, a replenishment toner container, and a toner The replenishment path is the same as those provided in the image forming apparatus according to the present embodiment.

  The toner replenishment path cleaning method according to the present embodiment includes a granular composition supply step of supplying and passing the specific granular composition to the toner replenishment path. Here, the granular composition supply step is the same as the granular composition supply step of the image forming method according to the present embodiment.

The toner replenishment path cleaning method according to the present embodiment is, for example, a method performed in an image forming apparatus including the means (i) or the means (ii), and the operation of the means (i) or the means (ii). A granular composition supply process is implemented by this.
In addition, the toner replenishment path cleaning method according to this embodiment is a method performed in an image forming apparatus that does not include the granular composition supply unit such as the unit (i) or the unit (ii). A granular composition supplying step is performed by the user of the apparatus putting the specific granular composition into the upstream portion of the toner supply path.

  Hereinafter, the image forming apparatus provided with the means (i) and the means (ii), and the granular composition supplying step by the means (i) and the means (ii) will be described with reference to the drawings. The form is not limited to this. In the following description, main parts shown in the drawings will be described, and description of the other parts will be omitted.

  2 and 3 are schematic configuration diagrams illustrating examples of an image holding member, a developing unit, a replenishing toner container, a toner replenishing path, and a granular composition supplying unit that are included in the image forming apparatus according to the present embodiment. . The configuration example shown in FIG. 2 is a configuration example provided with an example of the means (i), and the configuration example shown in FIG. 3 is a configuration example provided with an example of the means (ii).

  The configuration example illustrated in FIG. 2 includes a photosensitive member 102 that is an example of an image holding member, a developing device 104 that is an example of a developing unit, a detachable toner cartridge 106 that is an example of a replenishing toner storage unit, and a toner replenishment. Road 108. The toner replenishment path 108 includes an auger screw 110 that is an example of a toner conveying unit. A removable granular composition cartridge 112, which is an example of a granular composition supply unit, is provided outside or inside the image forming apparatus and can be replaced with the toner cartridge 106.

  The developing device 104 is divided into, for example, two chambers by a partition member. In one chamber, an outlet of the toner supply path 108 is provided, and in the other chamber, a developing roll facing the photoconductor 102 is provided. ing. The two chambers are connected to each other, and each chamber is provided with one stirring member that conveys the developer while stirring. The developer (not shown) in the developing device 104 is conveyed while being stirred by two stirring members, and is supplied to the developing roll.

  In the configuration example shown in FIG. 2, image formation is stopped according to a decrease in toner concentration of a developer (not shown) in the developing device 104, and the toner cartridge 106 is manually or automatically replaced with the granular composition cartridge 112. Subsequently, the auger screw 110 is operated to supply all or part of the specific granular composition contained in the granular composition cartridge 112 to the toner supply path 108. The granular composition cartridge 112 is replaced with the toner cartridge 106 after supplying the specific granular composition to the toner supply path 108. Thereafter, the auger screw 110 is operated to pass the specific granular composition through the toner supply path 108. By passing the specific granular composition, the toner adhering to the inner wall of the toner supply path 108 and the auger screw 110 is removed, and the toner aggregate in the toner supply path 108 is crushed. The specific granular composition that has passed through the toner supply path 108 enters the developing device 104.

  The configuration example illustrated in FIG. 3 includes a photosensitive member 102 that is an example of an image holding member, a developing device 104 that is an example of a developing unit, a detachable toner cartridge 106 that is an example of a replenishing toner storage unit, and a toner replenishment. A passage 108 and a granular composition supply means 114 are provided. The toner replenishment path 108 includes an auger screw 110 that is an example of a toner conveying unit. The granular composition supply means 114 includes a detachable granular composition cartridge 116 that is an example of a granular composition storage unit, and a granular composition supply path 118 that connects the granular composition cartridge 116 and the toner supply path 108. Yes. The granular composition supply path 118 includes an auger screw 120 which is an example of a conveying means for the granular composition. The developing device 104 in the configuration example shown in FIG. 3 has the same configuration as the developing device 104 in the configuration example shown in FIG.

  In the configuration example shown in FIG. 3, image formation is stopped in response to a decrease in toner concentration of a developer (not shown) in the developing device 104. Next, the auger screw 120 provided in the granular composition supply path 118 is operated, for example, 5 g to 20 g of the specific granular composition is conveyed from the granular composition cartridge 116 to the toner supply path 108, and the auger screw 120 is stopped. Thereafter, the auger screw 110 provided in the toner supply path 108 is operated to pass the specific granular composition through the toner supply path 108. By passing the specific granular composition, the toner adhering to the inner wall of the toner supply path 108 and the auger screw 110 is removed, and the toner aggregate in the toner supply path 108 is crushed. The specific granular composition that has passed through the toner supply path 108 enters the developing device 104.

  Hereinafter, materials, manufacturing methods, physical properties, and the like of the specific granular composition, the electrostatic charge image developer, and the replenishing toner will be described.

[Specific granular composition]
The density | concentration of the magnetic particle in a specific granular composition is 80 mass% or more, 90 mass% or more and 100 mass% or less are more preferable, 95 mass% or more and 100 mass% or less are still more preferable.

  Examples of the magnetic particles include granular magnetic metals (for example, iron, nickel, cobalt, etc.), granular magnetic oxides (for example, ferrite, magnetite, etc.), magnetic carriers known as carriers for two-component developers, and the like. It is done.

The volume average particle diameter of the magnetic particles is preferably 15 μm or more, more preferably 25 μm or more from the viewpoint of excellent cleaning properties of the toner replenishment path, and 80 μm or less is preferable from the viewpoint of excellent transportability of the magnetic particles and the granular composition. More preferably, it is 50 μm or less.
The particle size of the magnetic particles is measured using a laser diffraction / scattering particle size distribution analyzer (for example, LS Particle Size Analyzer: LS13 320, manufactured by Beckman Coulter, Inc.). For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size at 50% cumulative is taken as the volume average particle size.

The bulk density of the magnetic particles is preferably 1.5 g / ml or more, more preferably 2.0 g / ml or more from the viewpoint of excellent cleaning properties of the toner supply path, and 3.0 g / ml from the viewpoint of suppressing stress on the toner. ml or less is preferable, and 2.5 g / ml or less is more preferable.
The bulk density can be controlled by the composition, structure, particle size, etc. of the magnetic particles.
The bulk density can be measured according to JIS-Z2504 (apparent density measuring method).

  As an exemplary embodiment of the specific granular composition, there is a granular composition obtained by mixing a magnetic carrier and a toner so that the magnetic carrier concentration is 80% by mass or more. In this case, the concentration of the magnetic carrier is more preferably 90% by mass or more, and still more preferably 95% by mass or more.

As the magnetic particles contained in the granular composition, even when mixed with the developer in the developing means, there is little influence on the image. Therefore, from the viewpoint of further suppressing the occurrence of image defects, a magnetic carrier for the developer is preferable.
There is no restriction | limiting in particular as a magnetic carrier, A well-known magnetic carrier is mentioned. Examples of the magnetic carrier include a resin-coated carrier in which the surface of a core made of magnetic powder is coated with a resin; a magnetic powder-dispersed carrier in which magnetic powder is dispersed in a matrix resin; and resin in porous magnetic powder And the like. The magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which the constituent particles of the carrier are used as a core and the surface is coated with a resin.

  Examples of the magnetic powder constituting the magnetic carrier include magnetic metals such as iron, nickel and cobalt; and magnetic oxides such as ferrite and magnetite.

  Examples of the coating resin and the matrix resin include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, Acrylic resin, styrene-acrylic resin, straight silicone resin containing organosiloxane bond or modified product thereof, fluororesin, polyester, polyurethane, polycarbonate, phenol resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide Examples thereof include resins and epoxy resins. These resins may be used alone or in combination of two or more.

  The coating resin and the matrix resin may contain additives such as conductive particles and a charge control agent. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate. Among these, carbon black is preferable in terms of uniform dispersion in the resin and resistance control. The content of the conductive particles is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin.

  The coating resin and the matrix resin may contain resin particles. Examples of the resin particles include particles of silicone, polystyrene, polymethyl methacrylate, melamine resin, and the like.

  Examples of the method for coating the surface of the core material with the coating resin include a coating method using a coating layer forming solution in which the coating resin and various additives are dissolved in a solvent. Specifically, the coating method using the coating layer forming solution includes an immersion method in which the core material is immersed in the coating layer forming solution; a spray method in which the coating layer forming solution is sprayed on the surface of the core material; Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed in a state of being floated by flowing air; a kneader coater method in which a core material and a coating layer forming solution are mixed in a kneader coater, and a solvent is removed.

  The solvent used for preparing the coating layer forming solution is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like. Examples of the solvent include aromatic hydrocarbon compounds such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; halides of hydrocarbon compounds such as chloroform and carbon tetrachloride;

  The average thickness of the resin coating layer in the resin-coated carrier is preferably from 0.1 μm to 10 μm, and more preferably from 0.5 μm to 3 μm.

[Electrostatic image developer, toner for replenishment]
In this embodiment, the developer may be a one-component developer containing only toner, or may be a two-component developer in which toner and carrier are mixed. The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, more preferably 3: 100 to 20: 100 in the developing unit.

There is no restriction | limiting in particular as a toner contained in a developing agent, A well-known toner is mentioned. The toner includes, for example, toner particles and an external additive, and the toner particles include, for example, a binder resin, a colorant, a release agent, and other additives. The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be. The volume average particle size of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less. Examples of the external additive include inorganic particles (SiO ₂ , TiO ₂ , Al ₂ O _{3 and the} like) and resin particles (resin particles such as polystyrene, polymethyl methacrylate resin and melamine resin).

  In the exemplary embodiment, the replenishing toner is not particularly limited, and may be a known toner. The replenishing toner preferably has the same configuration as the toner contained in the developer in the developing unit.

  There is no restriction | limiting in particular as a carrier contained in a two-component developer, A well-known carrier is mentioned. Examples of the carrier include a resin-coated carrier in which the surface of a core made of magnetic powder is coated with a resin; a magnetic powder-dispersed carrier in which magnetic powder is dispersed in a matrix resin; and a resin in porous magnetic powder. And impregnated resin-impregnated carriers. The magnetic powder-dispersed carrier and the resin-impregnated carrier may be carriers in which the constituent particles of the carrier are used as a core and the surface is coated with a resin. Preferable examples of these carriers include the above-described magnetic carriers described as preferable examples of the magnetic particles contained in the specific granular composition.

  In this embodiment, when the magnetic particles contained in the specific granular composition are magnetic carriers, it is preferable that the magnetic carrier and the carrier contained in the developer contained in the developing unit have the same configuration. . When both have the same configuration, even if the specific granular composition is mixed with the developer in the developing means, the influence on the image is small, and therefore the occurrence of image defects is further suppressed.

  Hereinafter, the overall steps of the means and the image forming method included in the image forming apparatus will be described in detail.

  An image forming apparatus according to this embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic charge image forming unit that forms an electrostatic image on the surface of the charged image carrier, and toner. A developing means for containing an electrostatic image developer containing the toner and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer; and a toner image formed on the surface of the image carrier A transfer means for transferring the toner image onto the surface of the recording medium, a fixing means for fixing the toner image transferred to the surface of the recording medium, a replenishment toner accommodating portion for accommodating a replenishment toner replenished to the developing means, and a replenishment A toner replenishing path having toner conveying means for connecting replenishing toner to the developing means by connecting the toner container and the developing means, and a granular composition for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishing path A composition supply means; Equipped with a.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member An intermediate transfer type apparatus that primarily transfers the toner image transferred to the surface of the intermediate transfer body and then secondary transfer the toner image to the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. A known image forming apparatus such as an apparatus provided with a cleaning unit; an apparatus provided with a charge removing unit that discharges the surface of the image holding member with a discharge light before charging after transferring the toner image;
In the case where the image forming apparatus according to this embodiment is an intermediate transfer type apparatus, for example, the transfer unit intermediately transfers an intermediate transfer body on which a toner image is transferred onto the surface and a toner image formed on the surface of the image holding body. A configuration having primary transfer means for primary transfer onto the surface of the body and secondary transfer means for secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium is applied.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus.

  The image forming apparatus according to the present embodiment may use a one-component developer or a two-component developer as a developer. The image forming apparatus according to the present embodiment may be an image forming apparatus to which a so-called trickle developing method is applied, in which the developer and toner are supplied to the developing unit and the developer containing a large amount of deteriorated carrier is discharged.

  The image forming method according to the present embodiment includes a charging step for charging the surface of the image carrier, an electrostatic image forming step for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic image development including toner. A developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image by a developing means containing the agent, and a transfer for transferring the toner image formed on the surface of the image carrier to the surface of the recording medium Toner, a fixing step for fixing the toner image transferred on the surface of the recording medium, and a toner replenishing path that connects the replenishing toner accommodating portion and the developing means from the replenishing toner accommodating portion that accommodates the replenishing toner. A toner replenishing step for replenishing the developing means with toner for replenishment by toner conveying means in the replenishment path, and a granular composition supplying process for supplying and passing a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path. And, with a.

  Hereinafter, examples of an image forming apparatus and an image forming method according to the present embodiment will be described with reference to the drawings. However, the present embodiment is not limited thereto. In the following description, main parts shown in the drawings will be described, and description of the other parts will be omitted.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

  Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other in the left to right direction in the drawing. The vehicle travels in the direction toward the unit 10K. The support roll 24 is applied with a force in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the drive roll 22.

  The image forming apparatus shown in FIG. 1 includes detachable toner cartridges 8Y, 8M, 8C, and 8K that are examples of a replenishing toner storage unit, and a toner replenishing path (not shown). The developing devices 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are connected to the toner cartridges 8Y, 8M, 8C, and 8K through toner supply paths, respectively. Each color toner is supplied from the toner cartridges 8Y, 8M, 8C, and 8K to the developing devices 4Y, 4M, 4C, and 4K through the toner supply path.

  An embodiment of the image forming apparatus shown in FIG. 1 is an embodiment to which the means (i) is applied. In this case, one to four granular composition cartridges (not shown) containing the specific granular composition are provided, for example, near the toner cartridges 8Y, 8M, 8C, and 8K. When the means (i) is applied, the particulate composition cartridge and the toner cartridge are manually or automatically replaced, and the particulate composition supply step is performed.

  Another embodiment of the image forming apparatus shown in FIG. 1 is a form to which the means (ii) is applied. In this case, for example, the means (ii) (that is, the granular composition container and the granular composition supply path (not shown)) is provided in the vicinity of the toner cartridges 8Y, 8M, 8C, and 8K. One means (ii) may be provided for each color, or one granular composition storage section and one granular composition supply path for each color may be provided. When the means (ii) is applied, the specific granular composition is supplied from the granular composition container to the toner replenishment path through the granular composition supply path, and the granular composition supply step is performed.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first unit 10Y instead of yellow (Y). Description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y includes a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on the color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A primary transfer roll 5Y (an example of a primary transfer unit) that transfers a toner image onto the intermediate transfer belt 20 and a photoconductor cleaning device 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer are sequentially arranged. .
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. A bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (for example, volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (general resin resistance), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image having a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is developed and visualized as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged electric charge on the photoreceptor 1Y, and has a developer roll (a developer holding member). Example) is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force directed from the photoreceptor 1Y to the primary transfer roll 5Y is applied to the toner image, so that The toner image on the body 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to, for example, +10 μA by the control unit (not shown) in the first unit 10Y.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

The primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 on which the four color toner images are transferred in multiple ways through the first to fourth units is disposed on the image transfer surface side of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roll (an example of a secondary transfer unit) 26 is formed to a secondary transfer portion configured. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

  Thereafter, the recording paper P is fed into the pressure contact portions (nip portions) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image.

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. In addition to the recording paper P, the recording medium may be an OHP sheet.
In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is also preferably smooth. For example, coated paper with the surface of plain paper coated with resin, art paper for printing, etc. are preferably used. Is done.

  The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment contains an electrostatic charge image developer containing toner, and developing means for developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer, A toner replenishing path that internally connects a replenishing toner accommodating portion that accommodates replenishing toner to be replenished to the developing means, a toner replenishing path that connects the replenishing toner accommodating portion and the developing means, and conveys the replenishing toner to the developing means. And a granular composition supply means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path, and is a process cartridge that can be attached to and detached from the image forming apparatus. Examples of the particulate composition supply means include the means (i) and the means (ii) described above.

  The process cartridge according to the present embodiment is not limited to the above-described configuration, and includes, for example, at least one selected from other units such as an image holding member, a charging unit, an electrostatic charge image forming unit, and a transfer unit. There may be.

  Hereinafter, embodiments of the present invention will be described in detail by way of examples, but the embodiments of the present invention are not limited to these examples. In the following description, “part” and “%” are based on mass unless otherwise specified.

<Preparation of coating layer forming solution 1>
・ Toluene 85 parts ・ Polycyclohexyl methacrylate resin 15 parts ・ Carbon 2 parts ・ Crosslinked melamine resin particles (Eposter S, manufactured by Nippon Shokubai Co., Ltd.) 1 part Then, carbon and crosslinked melamine resin particles were added thereto, and the mixture was stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 1.

<Preparation of resin-coated magnetic particles 1>
Ferrite particles (Mn—Mg ferrite, volume average particle size 40 μm, bulk density 2.20 g / ml, saturation magnetization 60 emu / g) 100 parts ・ Coating layer forming solution 1 12 parts The above materials are put into a kneader and heated to 60 ° C. After heating, the temperature was kept at 60 ° C. and stirred for 10 minutes, and then the pressure was reduced to distill off toluene. Furthermore, it heated at 70 degreeC, pressure-reduced, toluene was distilled off, and the resin coating magnetic particle was obtained. The resin-coated magnetic particles were sieved with a mesh having an opening of 75 μm to obtain resin-coated magnetic particles 1 (volume average particle size 42 μm, bulk density 2.22 g / ml).

<Example 1>
A cartridge containing the resin-coated magnetic particles 1 and a modified Apeos Port-IV C5570 manufactured by Fuji Xerox Co., Ltd., capable of mounting the cartridge were prepared. The remodeling machine includes a toner cartridge and a toner replenishment path that connects the toner cartridge and the developing device, and a toner concentration sensor that detects the toner concentration is disposed in the developing device. A developer formed by mixing the resin-coated magnetic particles 1 and toner was placed in the developing device of this modified machine.

  Using the above-described remodeling machine in an environment of a temperature of 38 ° C. and a relative humidity of 85%, one image of an image density of 100% was formed and then stopped (the first output image is “image 1”). And). When the toner density in the developing device became 1% lower than the set value, the toner cartridge was replaced with a cartridge containing resin-coated magnetic particles 1, and 10 g of resin-coated magnetic particles 1 were supplied to the toner supply path. After supplying the resin-coated magnetic particles 1, the auger screw included in the toner supply path was activated by forming 100 images of the image, thereby causing the resin-coated magnetic particles 1 to pass through the toner supply path. Thereafter, one image having an image density of 100% was output (this is referred to as “image 2”). Next, one image including a halftone image having an image density of 20% and a thin line having a thickness of 200 μm was output (this is referred to as “image 3”).

[Evaluation of concentration]
The density of image 1 and image 2 was evaluated by reading the numerical value of a reflection spectral densitometer (X-Rite manufactured by X-Rite), and the density difference (ΔSAD) between image 1 and image 2 was obtained. ΔSAD 0.10 or less is an allowable range.

[Evaluation of color streaks]
Image 3 was visually evaluated and classified as follows. An acceptable evaluation result is A.
A: No color streak is generated.
B: One to four color streaks are generated.
C: Five or more color streaks have occurred.

[Evaluation of fine line reproducibility]
Image 3 was visually evaluated and classified as follows. An acceptable evaluation result is A.
A: Non-uniformity is not recognized in the fine line.
B: Fine lines are felt slightly uneven.
C: Non-uniformity is clearly observed in the thin line.

<Example 2>
95 parts of the resin-coated magnetic particles 1 and 5 parts of the toner were stirred at 40 rpm for 20 minutes using a V blender, and sieved using a sieve of 125 μm mesh to obtain a mixture. A cartridge containing this mixture was prepared.
Image formation was performed in the same manner as in Example 1 except that the cartridge containing the resin-coated magnetic particles 1 was changed to a cartridge containing the mixture.

<Example 3>
80 parts of resin-coated magnetic particles 1 and 20 parts of toner were stirred for 20 minutes at 40 rpm using a V blender, and sieved using a sieve having a 125 μm mesh to obtain a mixture. A cartridge containing this mixture was prepared.
Image formation was performed in the same manner as in Example 1 except that the cartridge containing the resin-coated magnetic particles 1 was changed to a cartridge containing the mixture.

<Example 4>
As magnetic particles, magnetite-dispersed resin particles (magnetic powder-dispersed carrier in which magnetite is dispersed in matrix resin, matrix resin is thermosetting resin (phenol resin), volume average particle size 35 μm, bulk density 1.6 g / ml) A cartridge containing the magnetic particles was prepared.
Image formation was performed in the same manner as in Example 1 except that the cartridge containing the resin-coated magnetic particles 1 was changed to a cartridge containing the magnetic particles.

<Example 5>
Magnetic particles obtained by heat-treating ferrite particles (Mn—Mg ferrite particles, volume average particle size 80 μm, bulk density 2.8 g / ml) as magnetic particles at 500 ° C. for 1 hour in an atmosphere with an oxygen concentration of 20%. A cartridge containing the magnetic particles was prepared.
Image formation was performed in the same manner as in Example 1 except that the cartridge containing the resin-coated magnetic particles 1 was changed to a cartridge containing the magnetic particles.

<Comparative Example 1>
An image was formed in the same manner as in Example 1 except that the resin-coated magnetic particles 1 were not supplied to the toner supply path.

<Comparative example 2>
70 parts of resin-coated magnetic particles 1 and 30 parts of toner were stirred at 40 rpm for 20 minutes using a V blender, and sieved using a sieve having a 125 μm mesh to obtain a mixture. A cartridge containing this mixture was prepared.
Image formation was performed in the same manner as in Example 1 except that the cartridge containing the resin-coated magnetic particles 1 was changed to a cartridge containing the mixture.

  Table 1 shows the configurations and evaluation results of the examples and comparative examples.

1Y, 1M, 1C, 1K photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning devices 8Y, 8M, 8C, 8K Toner cartridges 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll
24 support roll 26 secondary transfer roll (an example of secondary transfer means)
28 Fixing device (an example of fixing means)
30 Intermediate transfer member cleaning device P Recording paper (an example of a recording medium)

102 photoconductor (an example of an image carrier)
104 Developing device (an example of developing means)
106 Toner cartridge (an example of a toner container for replenishment)
108 Toner replenishment path 110 Auger screw (an example of toner conveying means)
112 Granular composition cartridge (an example of granular composition supply means)
114 Granular composition supply means 116 Granular composition cartridge (an example of a granular composition container)
118 granular composition supply path 120 auger screw (an example of means for conveying granular composition)

Claims (16)

An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A granular composition supply means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the magnetic particles are a carrier for an electrostatic charge image developer.   The image forming apparatus according to claim 1, wherein a volume average particle diameter of the magnetic particles is 15 μm or more and 80 μm or less.   The image forming apparatus according to claim 1, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less. Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A granular composition supply means for supplying a granular composition containing 80% by mass or more of magnetic particles to the toner supply path;
And a process cartridge that is detachably attached to the image forming apparatus.   The process cartridge according to claim 5, wherein the magnetic particles are a carrier for an electrostatic charge image developer.   The process cartridge according to claim 5 or 6, wherein a volume average particle size of the magnetic particles is 15 µm or more and 80 µm or less.   The process cartridge according to claim 5, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less. A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image by a developing unit containing an electrostatic charge image developer containing toner;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
The replenishing toner is supplied to the developing means by the toner transporting means in the toner replenishing path through the toner replenishing path connecting the replenishing toner containing part and the developing means from the replenishing toner containing section for storing the replenishing toner. A toner replenishment process for replenishing
A granular composition supplying step of supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path and passing the granular composition;
An image forming method comprising:   The image forming method according to claim 9, wherein the magnetic particles are a carrier for an electrostatic charge image developer.   The image forming method according to claim 9 or 10, wherein a volume average particle diameter of the magnetic particles is 15 µm or more and 80 µm or less.   The image forming method according to claim 9, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing an electrostatic charge image developer containing toner, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
A replenishment toner accommodating portion for accommodating replenishment toner replenished to the developing means;
A toner replenishing path that connects the replenishing toner container and the developing means, and has toner conveying means for conveying the replenishing toner to the developing means;
A toner replenishment path cleaning method performed in an image forming apparatus comprising:
A method for cleaning a toner replenishment path, comprising: supplying a granular composition containing 80% by mass or more of magnetic particles to the toner replenishment path.   The toner replenishment path cleaning method according to claim 13, wherein the magnetic particles are a carrier for an electrostatic charge image developer.   The toner replenishment path cleaning method according to claim 13 or 14, wherein a volume average particle diameter of the magnetic particles is 15 µm or more and 80 µm or less. The toner replenishment path cleaning method according to any one of claims 13 to 15, wherein a bulk density of the magnetic particles is 1.5 g / ml or more and 3.0 g / ml or less.