JP5655510B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these. In particular, development is performed by supplying toner in the developer to the electrostatic latent image formed on the image bearing member from a developing device using a developer containing toner and carrier, and the deteriorated carrier is included in the developing device. When the developer is discharged from the developing device, and the new developer is replenished into the developing device from the developer containing the developer containing toner and carrier, the carrier in the developer in the developing device deteriorates. It is characterized in that the amount of carrier in a new developer to be replenished from the developer container into the developing device can be controlled easily and appropriately according to the state.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a composite machine of these, toner is supplied from a developing device to develop an electrostatic latent image formed on an image carrier. As such a developing device, a one-component developing type developing device using only toner as a developer and a two-component developing type developing device using a developer containing toner and a carrier are known. Yes. A two-component developing system using a developer containing a toner and a carrier is excellent from the viewpoint of quickly and appropriately charging the toner to form a high-speed image.

  Here, in a two-component developing type developing device using a developer containing a toner and a carrier, generally, the toner is charged by mixing and stirring the toner and the carrier in the developing device, and the toner thus charged is charged. Is developed to the electrostatic latent image formed on the image carrier, and when the amount of toner in the developer is reduced as a result of supplying the toner in this way, a new toner is developed. To be replenished.

  In addition, when the developing device is replenished with new toner and developed for a long period of time, the carrier in the developer in the developing device gradually deteriorates, and the toner cannot be charged properly, or the carrier Is supplied to the image carrier, which causes a problem that appropriate image formation cannot be performed.

  Therefore, in recent years, a part of the developer in the developing device is discharged, and a new carrier or a developer containing a new carrier is supplied into the developing device.

  Here, when a new carrier or a developer containing a new carrier is replenished in the developing device as described above, an appropriate amount of a new carrier is supplied into the developing device in accordance with the deterioration state of the carrier in the developing device. Various schemes have been proposed for this purpose.

  For example, in Japanese Patent Application Laid-Open No. 2005-228867, in addition to a toner container that contains new toner, a carrier container that contains a new carrier is provided, and in addition to supplying new toner from the toner container, development in the developing device is performed. A device in which a new carrier is supplied from a carrier container according to conditions and the like is shown.

  However, as shown in Patent Document 1, in the case of using a carrier container that contains a new carrier in addition to a toner container that contains a new toner, the apparatus becomes large and the toner container and the carrier container Therefore, a mechanism for supplying the toner and the carrier separately is necessary, and the cost is high.

  In Patent Document 2, when a partition is provided in one developer supply cartridge so that new toner and a new carrier are accommodated separately, and the amount of toner in the developer in the developing device decreases, The new toner contained in one side is replenished into the developing device, and when the carrier is destroyed and deteriorated, it is contained in one side together with the new carrier contained in the other side. A new toner is supplied in an appropriate amount into the developing device, and the toner density in the developer in the developing device is appropriately maintained.

  However, even in the one disclosed in Patent Document 2, a partition is provided in the developer supply cartridge so that new toner and new carrier are stored separately, and thus the new toner and new carrier stored separately in this manner are stored. In order to supply them separately, a mechanism for supplying them separately is required, resulting in high costs.

JP 2007-47711 A JP 2007-322840 A

  The image forming apparatus of the present invention is to solve the above-described problems, and from an developing device using a developer containing toner and a carrier to an electrostatic latent image formed on an image carrier. Development is performed by supplying toner in the developer, and the developer containing the deteriorated carrier in the developing device is discharged from the developer device, while the developer containing the developer containing the toner and the carrier is discharged from the developer containing body. When replenishing a new developer into the developing device, the amount of carrier in the new developer to be replenished from the developer container into the developing device can be controlled easily and appropriately according to the deterioration state of the carrier in the developing device. The purpose is to do so.

In order to solve the above-described problems, the image forming apparatus of the present invention supplies toner in a developer containing toner and a carrier to the image carrier to develop the electrostatic latent image formed on the image carrier. a developing device, a developer discharge means for discharging the developer in the developing device includes a developer container that is containing a developer including a toner and a carrier, the developer contained in the developer container body A developer replenishing means for replenishing the developing device, and when the developer is replenished from the developer container to the developing device by the developer replenishing means, the carrier in the replenished developer is held and developed. in the image forming apparatus and a control means for controlling the amount of carrier to be supplied to the apparatus, the above developer container, carrying spiral for conveying the developer contained in the developer containing body around a cylindrical A magnetic carrier is used as the carrier, and a magnetic means for magnetically holding the magnetic carrier in the developer is used as the control means. The magnetic means is used as a developer container. A plurality of the toner containers are provided in the axial direction of the developer container at a predetermined interval so as to be close to the developer container on the outer peripheral side of the toner container.

Here, when a plurality of the magnetic force means are provided in the axial direction of the developer accommodating body with a predetermined interval, the magnetic means is provided at an interval corresponding to the pitch of the conveying spiral provided on the developer accommodating body. be able to.

  In the image forming apparatus of the present invention, the amount of carrier in the developer to be replenished in the developing device is controlled by the above-described control means in accordance with the deterioration state of the carrier in the developer in the developing device. Like that. The deterioration state of the carrier in the developer in the developing device can be appropriately determined according to the driving time of the developing device, the amount of toner supplied from the developing device to the image carrier, and the like.

  In the image forming apparatus according to the present invention, the developer replenished by the control means when the developer is replenished into the developing device from the developer containing body containing the developer containing toner and carrier by the developer replenishing means. The carrier inside is held and the amount of the carrier to be replenished in the developing device is controlled.

  For this reason, in the image forming apparatus according to the present invention, a carrier containing container containing a new carrier is used in addition to a toner containing container containing new toner as in the prior art, or a single developer supply cartridge is used. There is no need to provide a partition to store new toner and new carrier separately, and there is no need to provide a mechanism for supplying toner and carrier separately, which increases the size of the apparatus. The cost is also reduced.

1 is a schematic explanatory diagram of an image forming apparatus according to an embodiment of the present invention. In the image forming apparatus according to the above-described embodiment, the state in which the amount of carrier in the developer to be replenished is controlled by the control unit when the developer accommodated in the developer accommodating body is replenished into the developing device through the transport unit. It is the shown schematic explanatory drawing. In the image forming apparatus according to the above-described embodiment, it is a schematic explanatory diagram illustrating a configuration in which a control unit controls the amount of carrier in the developer to be replenished from the developer container into the developing device.

  An image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the image forming apparatus according to the present invention is not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In the image forming apparatus according to this embodiment, as shown in FIGS. 1 and 2, a developer containing toner and a magnetic carrier corresponding to the four drum-shaped photoconductors (image carriers) 10. Four developing devices 20 accommodating D are provided.

  Each developing device 20 is provided with a developing roller 21 that rotates and conveys the developer to the photoconductor 10 so as to face the corresponding photoconductor 10, and each developing device 20 has a respective developing device. Black, yellow, magenta, and cyan toners are used in different colors in the toner.

  In this image forming apparatus, when the image is formed, the respective photoreceptors 10 are rotated, and the surface of each photoreceptor 10 is charged by the charging device 11, respectively. 10 is exposed by the latent image forming device 12 according to the image formation information, and an electrostatic latent image is formed on the surface of each photoconductor 10.

  Next, with respect to each photoconductor 10 on which the electrostatic latent image is formed in this way, the developer D in the corresponding developing device 20 is guided to a position facing the photoconductor 10 by the developing roller 21, and each developer The toner of a predetermined color in D is supplied to the electrostatic latent image of each photoconductor 10 and development is performed to form a toner image of each color on the surface of each photoconductor 10.

  Then, the toner images of the respective colors formed on the respective photoconductors 10 in this manner are sequentially transferred by the primary transfer roller 14 to the intermediate transfer belt 13 which is in the form of an endless belt that is driven across the roller 13a. And a full-color toner image is formed on the intermediate transfer belt 13.

  Thereafter, each of the photoreceptors 10 is guided to the first cleaning device 15, and the residual toner or the like remaining on the surface of each photoreceptor 10 is removed from the surface of each photoreceptor 10 by each first cleaning device 15. After removal and collection, the surface of each photoconductor 10 is charged again by the charging device 11 as described above.

  On the other hand, the full-color toner image formed on the intermediate transfer belt 13 as described above is guided to a position facing the secondary transfer roller 16 by the intermediate transfer belt 13 and is stored in the lower part of the image forming apparatus. The recorded sheet S is guided between the intermediate transfer belt 13 and the secondary transfer roller 16, and the full-color toner image formed on the intermediate transfer belt 13 by the secondary transfer roller 16 is transferred onto the recording sheet S. Next transfer is done.

  Then, the recording sheet S to which the full color toner image is transferred in this way is guided to the fixing device 17, and the transferred full color toner image is fixed to the recording sheet S, and then the recording in which the full color toner image is fixed. The sheet S is discharged. On the other hand, the residual toner such as toner remaining on the intermediate transfer belt 13 without being transferred to the recording sheet S is removed from the intermediate transfer belt 13 by the second cleaning device 18 and collected.

  Here, in the developing device 20, as shown in FIG. 2, a partition wall 22 is provided in the developing device 20 along the axial direction of the developing roller 21, and the partition wall 22 and the first developer transport unit 23 are connected to the first developer transport unit 23. The first agitating and conveying member 23a and the second agitating member which are separated into the two developer conveying portions 24 and which convey the developer D while being mixed and agitated to the first developer conveying portion 23 and the second developer conveying portion 24. Conveying member 24a is provided.

  Then, the first agitating and conveying member 23a and the second agitating and conveying member 24a are rotated to mix and agitate the developer D, and the toner in the developer D is charged by contact with the carrier while the first developer is charged. The transport unit 23 transports the developer D along the developing roller 21 and supplies a part of the developer D to the developing roller 21, while the second developer transport unit 24 supplies the developer D to the first roller. The developer D is conveyed in the direction opposite to that of the developer conveying unit 23, and the developer D is circulated between the first developer conveying unit 23 through circulation ports (not shown) provided at both ends of the partition wall 22. .

  Further, as described above, the developer D supplied to the developing roller 21 in the first developer conveying portion 23 is being conveyed to the photosensitive member 10 by the developing roller 21, and the photosensitive member 10 is developed by the developing roller 21 by the regulating member 25. The amount of the developer D guided to 1 is regulated.

  Then, the developer D regulated in this way is guided to a position facing the photoconductor 10 by the developing roller 21, and the toner in the developer D is supplied to the portion of the electrostatic latent image formed on the surface of the photoconductor 10. In addition, a toner image corresponding to the electrostatic latent image is formed on the surface of the photoconductor 10.

  Here, in the developing device 20, a toner concentration sensor 26 that detects the amount of toner in the developer D is provided in the second developer conveying unit 24, and excess developer D is discharged from the developing device 20. Developer discharge means 27 is provided. Then, the toner amount in the developer D detected by the toner density sensor 26 is output to the control means 30. In this embodiment, the developer discharging means 27 for discharging the excess developer D from the developing device 20 is provided in the second developer conveying portion 24, but is provided in the first developer conveying portion 23. It is also possible to do so.

  Further, in the image forming apparatus of this embodiment, as shown in FIGS. 1 to 3, as a developer replenishing unit 40, a cylindrical developer container 41 corresponding to each developing device 20 is provided. The developer containing body 41 stores the developer D including the toner of the color corresponding to the toner in each developing device 20 and the carrier, and transports the developer D contained in each developer containing body 41 respectively. Each developing device 20 is replenished through the section 42.

  In the developing device 20, if the amount of toner in the developer D detected by the toner density sensor 17 is less than a predetermined amount, and this is detected by the control means 30, the corresponding developer The container 41 is rotated by a rotating device (not shown), and the developer D accommodated in the developer container 41 is conveyed by a conveying spiral 41 a provided around the developer container 41 to supply the replenishing port. (Not shown) is guided to the conveyance unit 42, and the developer D is supplied into the developing device 20 through the conveyance unit 42. Further, the developer D that has been replenished from the developer container 41 and becomes excessive in the developing device 20 is discharged from the developer discharging means 27.

  Here, in this embodiment, the transport unit 42 is provided with an auxiliary hopper 42a for storing the developer D discharged from the replenishing port of the developer container 41, and the auxiliary hopper 42a is passed through the transport pipe 42b. A fixed amount of developer D is supplied into the developing device 20. However, the auxiliary hopper 42a is not necessarily provided, and the developer D guided to the replenishing port of the developer container 41 may be directly guided to the developing device 20 through the transport pipe 42b.

  In the image forming apparatus according to this embodiment, the carrier in the developer D is used when the control unit 30 controls the amount of the carrier in the developer D supplied from the developer container 41 into the developing device 20. As shown in FIG. 3, a plurality of electromagnets 31 are provided so as to be close to the developer container 41 along the axial direction of the developer container 41. The control means 30 controls on / off of each electromagnet 31 and the magnetic force in each electromagnet 31 to control the amount of carrier in the developer D conveyed in the developer container 41. In addition, the amount of carrier in the developer D supplied from the developer container 41 into the developing device 20 is controlled.

  In controlling the amount of carrier in the developer D supplied from the developer container 41 into the developing device 20 as described above, the toner density sensor 26 detects the control means 30 as described above. The amount of toner in the developer D in the developing device 20 is output, and image formation information such as a printing rate is output from the CPU 50. Based on these results, the control unit 30 supplies the developing device 20 with replenishment. The amount of carrier in the developer D is controlled.

  For example, when an image with a low printing rate is formed, the amount of toner consumed in forming one image is small, the number of sheets on which image formation is performed before the toner supply is performed, and the driving time of the developing device 20 is increased. Therefore, the carrier in the developer D deteriorates in the developing device 20 until the toner is replenished. On the other hand, when an image with a high printing rate is formed, the amount of toner consumed in forming one image is large, and the number of sheets on which image formation is performed is reduced before the toner is replenished. Therefore, the carrier in the developer D is less likely to deteriorate in the developing device 20 until the toner is replenished.

  For this reason, in consideration of the image printing rate, the driving time of the developing device 20, and the like, the number of times the electromagnet 31 is not turned on or turned on by the control means 30 when many images with a low printing rate are formed. The amount of the carrier in the developer D supplied from the developer container 41 into the developing device 20 is reduced by reducing the amount of the carrier held in the developer container 41 by the electromagnet 31. To increase. On the other hand, when a large number of images with a high printing rate are formed, the developer accommodating body 41 is used by the electromagnet 31 such that the electromagnet 31 is always turned on by the control means 30 or the number of times of turning on is increased. The amount of the carrier held inside is increased, and the amount of the carrier in the developer D supplied from the developer container 41 into the developing device 20 is decreased. If it does in this way, according to the deterioration state of the carrier in the developing agent D in the developing device 20, an appropriate amount of carrier will be supplied, and it will also be suppressed that a carrier is consumed wastefully.

  In this embodiment, as the magnetic force means 31 for magnetically holding the carrier in the developer D, a plurality of electromagnets 31 are arranged in the axial direction of the developer container 41 so as to be close to the developer container 41. However, it is also possible to use a permanent magnet as the magnetic force means, and make the permanent magnet approach and separate from the developer container 41.

  In this embodiment, the magnetic force means 31 for magnetically holding the carrier in the developer D is provided at a position close to the developer container 41. However, the magnetic force means 31 is provided in the auxiliary hopper 42a or It is also possible to provide the developer D from the auxiliary hopper 42 a at the position of the transport pipe 42 b that guides the developer D to the developing device 20, or to provide the developer D inside the developer container 41.

  In this embodiment, a cylindrical container is used as the developer container 41 for accommodating the developer D including toner and carrier. However, the developer container 41 in a bottle shape is used. It is also possible to use.

10 Photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 11 Charging device 12 Latent image forming device 13 Intermediate transfer belt 13a Roller 14 Primary transfer roller 15 First cleaning device 16 Secondary transfer roller 17 Fixing device 18 Second cleaning device 20 Developing device 21 Developing roller 22 Partition wall 23 First developer transport Portion 23a First stirring and conveying member 24 Second developer conveying portion 24a Second stirring and conveying member 25 Restricting member 26 Toner concentration sensor 27 Developer discharging means 30 Control means 31 Magnetic means (electromagnet)
40 Developer Supplying Unit 41 Developer Container 41a Transport Spiral 42 Transport Unit 42a Auxiliary Hopper 42b Transport Pipe 50 CPU
D Developer S Recording sheet

Claims (3)

Developing device for supplying toner in developer including toner and carrier to image carrier to develop electrostatic latent image formed on image carrier, and developer discharging means for discharging developer in the developing device A developer container that contains a developer containing toner and a carrier, a developer supply unit that replenishes the developer stored in the developer container into the developing device, and the developer supply unit described above And a control means for controlling the amount of the carrier to be replenished in the developing device by holding the carrier in the replenished developer when the developer is replenished into the developing device from the developer container. in forming apparatus, the above developer container, together with the use one conveying spiral for conveying the developer contained in the developer containing body around a cylindrical is provided, the magnetic calibration of the above carrier In addition, magnetic force means for magnetically holding the magnetic carrier in the developer is used as the control means, and the magnetic force means is placed close to the developer container on the outer peripheral side of the developer container. An image forming apparatus comprising a plurality of developer containers provided in the axial direction at a predetermined interval. 2. The image forming apparatus according to claim 1, wherein a plurality of the magnetic force means are provided at a predetermined interval in the axial direction of the developer container, corresponding to the pitch of the conveying spiral provided in the developer container. An image forming apparatus provided at a predetermined interval . 3. The image forming apparatus according to claim 1 , wherein the control unit is configured to supply a carrier in the developer to be replenished in the developing device in response to a deterioration state of the carrier in the developer in the developing device. An image forming apparatus characterized by controlling the amount.

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