JPH11295982A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing the flocculation of toner in a toner cartridge, obtaining a good-quality image and restraining power consumption regardless of left-standing environment when a power source is left in an off-state in the image forming device equipped with a rotary type developing device. SOLUTION: This image forming device is equipped with the rotary type developing device 5 constituted by arranging plural developing devices 19 (19Bk, etc.), around a turning shaft and performing development by turning the optional developing device out of plural developing devices 19 to a developing position opposed to a photoreceptor 1 with the turning shaft as center; a toner hopper 37 (37Bk, etc.), arranged at one end of the developing device; and the toner cartridge 36 (36Bk, etc.), attachably/detachably attached to the toner hopper and integrally turned with the developing device. When the power source is turned off in a device main body, temperature in the vicinity of the toner cartridge is detected by a temperature detection means 33 and the easiness of the flocculation of the toner in the toner cartridge is predicted based on the detected temperature, and the interval of the rotating operation of the developing device performed by a developing device rotating means is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, a printer, and the like. More specifically, a plurality of developing devices are arranged around a rotation axis. A developing device for performing development by rotating an arbitrary developing device to a developing position facing the latent image carrier around the rotation axis; and a developing device disposed at one end of the developing device and supplying the developing device. The present invention relates to an image forming apparatus including a developer accommodating portion accommodating a developer, and a toner cartridge detachably attached to the developer accommodating portion and rotating integrally with the developing device.

[0002]

2. Description of the Related Art Generally, a toner used in an image forming apparatus has a property of coagulating when left for a long period of time.
If the toner agglomerated in the toner cartridge is mixed into the developer of the developing device, the toner is not sufficiently agitated, and insufficiently charged toner is generated, thereby causing image smearing. Also,
There is a risk that the toner that has been aggregated will be developed, and the aggregated toner will appear as a large lump in the image. In order to solve such a problem, in the image forming apparatus, the toner in the toner cartridge is agitated by the rotation of the developing device to prevent the toner from aggregating. The prevention of toner aggregation due to the rotation of the developing device has been performed when the power of the image forming apparatus is ON. However, toner aggregation is likely to occur when the image forming apparatus has been left for a long time with the power supply turned off. Further, the toner has a property that the cohesion degree increases as the standing time increases (see FIG. 8), and a property that the cohesion degree of the toner whose cohesion degree once increases does not easily fall to a certain level or less even if agitated no matter how much. 9). Therefore, even when the developing device is rotated when the power of the image forming apparatus is turned on and the toner left for a long time in the power-off state is agitated, the hardly aggregated toner cannot be sufficiently loosened.

Accordingly, the present inventor has proposed an image forming apparatus that stirs the toner in a toner cartridge by periodically rotating the developing apparatus while the power of the image forming apparatus is OFF. According to this image forming apparatus,
Aggregation of toner when the image forming apparatus has been left for a long time with the power supply turned off can be suppressed.

[0004]

However, the toner has a characteristic that the easiness of aggregation changes depending on the temperature and humidity. As shown in FIG. 10, when the temperature is high, the toner tends to aggregate, and when the temperature is low, the toner is unlikely to aggregate. Also, as shown in FIG. 11, when the humidity is high, the toner is likely to aggregate, and when the humidity is low, the toner is unlikely to aggregate. For this reason, when the cohesion degree of the toner changes in response to the change in temperature or humidity near the toner cartridge, the image forming apparatus according to the above proposal performs the toner agitation periodically, so Toner stirring operation cannot be performed. For example, if the toner stirring operation is performed at a certain time interval t0, the toner is likely to aggregate when the temperature or humidity rises. Therefore, the aggregated toner cannot be sufficiently loosened at this time interval t0. On the other hand, if the temperature or humidity decreases, the toner is less likely to aggregate, so that at the time interval t0, aggregation of the toner can be prevented, but wasteful power is consumed.

The present invention has been made in view of the above background, and an object of the present invention is to provide an image forming apparatus provided with a rotary developing device in an environment where the power supply is turned off and the apparatus is left unattended. Another object of the present invention is to provide an image forming apparatus capable of preventing toner in a toner cartridge from aggregating, obtaining a high-quality image, and suppressing power consumption.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of developing devices are arranged around a rotation axis, and an arbitrary developing device among the plurality of developing devices is provided. A developing device that rotates the developing device around a rotation axis to a developing position facing the latent image carrier to perform development, and a developer device that is disposed at one end of the developing device and supplies developer to the developing device. An image forming apparatus comprising: a developer accommodating portion; and a developer cartridge detachably attached to the developer accommodating portion and rotating integrally with the developing device. A developing device rotating unit for rotating the developing device to agitate the toner in the toner cartridge, a temperature detecting unit for detecting a temperature near the toner cartridge, and the developing device rotating unit based on the detected temperature. Developing device It is characterized in that a developing device rotary interval control means for controlling the spacing of the rotation operation.

In the image forming apparatus according to the first aspect, based on the detected temperature in the vicinity of the toner cartridge, the susceptibility of the toner in the toner cartridge to coagulate is predicted, and the developing device is operated when the power is off. The interval of the rotation operation is controlled, the toner is stirred by the rotation operation, and aggregation is prevented. For example, when the temperature near the toner cartridge is high and the degree of aggregation of the toner is predicted to be high, the rotating operation of the developing device is performed at short intervals to loosen the aggregated toner. On the other hand, when the temperature is low and the degree of aggregation of the toner is predicted to be low, the rotation operation of the developing device is performed at a long interval to prevent the aggregation of the toner and reduce power consumption by the rotation operation.

According to a second aspect of the present invention, a plurality of developing devices are arranged around a rotation axis, and any one of the plurality of developing devices can be connected to a latent image around the rotation axis. A developing device for performing development by rotating to a developing position opposed to the carrier, a developer accommodating portion disposed at one end of the developing device and accommodating a developer to be supplied to the developing device; and a developer accommodating portion. An image forming apparatus having a developer cartridge detachably attached to the developing device and rotating integrally with the developing device, for agitating the toner in the toner cartridge when the apparatus main body is turned off. Developing device rotating means for rotating the developing device; humidity detecting means for detecting humidity in the vicinity of the toner cartridge; and developing for controlling an interval of rotation of the developing device performed by the developing device rotating device based on the detected humidity. Equipment times It is characterized in that a spacing control means.

According to the image forming apparatus of the present invention, the tendency of the toner in the toner cartridge to agglomerate is predicted based on the detected humidity in the vicinity of the toner cartridge. The interval of the rotation operation is controlled, the toner is stirred by the rotation operation, and aggregation is prevented. For example, when the humidity near the toner cartridge is high and the degree of aggregation of the toner is predicted to be high, the rotating operation of the developing device is performed at short intervals to loosen the aggregated toner. On the other hand, when it is predicted that the humidity is low and the degree of aggregation of the toner is low, the rotation operation of the developing device is performed at a long interval to prevent the aggregation of the toner and reduce power consumption by the rotation operation.

According to a third aspect of the present invention, a plurality of developing devices are arranged around a rotation axis, and any one of the plurality of developing devices is connected to a latent image around the rotation axis. A developing device for performing development by rotating to a developing position opposed to the carrier, a developer accommodating portion disposed at one end of the developing device and accommodating a developer to be supplied to the developing device; and a developer accommodating portion. An image forming apparatus having a toner cartridge detachably attached to the developing device and rotating integrally with the developing device, the developing device for stirring the toner in the toner cartridge when the apparatus main body is turned off. Developing device rotating means for rotating the device, temperature detecting means for detecting a temperature near the toner cartridge, humidity detecting means for detecting humidity,
Developing device rotation interval control means for controlling an interval of a rotation operation of the developing device performed by the developing device rotating means when the power is off based on the detected temperature and humidity. It is.

In the image forming apparatus according to the third aspect, based on the detected temperature and humidity near the toner cartridge,
It predicts the easiness of aggregation of the toner in the toner cartridge, controls the interval of the rotation operation of the developing device performed when the power is off, stirs the toner by the rotation operation, and prevents aggregation. For example, when the temperature and humidity near the toner cartridge are high and the degree of aggregation of the toner is predicted to be high, the rotating operation of the developing device is performed at short intervals to loosen the aggregated toner. On the other hand, when the temperature and humidity are low and the degree of aggregation of the toner is predicted to be low, the rotation operation of the developing device is performed at a long interval to prevent the aggregation of the toner and reduce the power consumption by the rotation operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic image forming apparatus will be described below.
1 is a front view illustrating a schematic configuration of an image forming apparatus according to an embodiment. First, an outline of the entire image forming apparatus will be described. A charger 2 serving as a charging unit is provided around a photoreceptor 1 serving as a latent image carrier which rotates in the direction of an arrow in FIG.
Photoreceptor potential detecting device 3, exposing device 4, rotary developing device 5, reflection density sensor 6, intermediate transfer belt 8
And a photoconductor cleaning 7 and the like. A primary transfer charger 9, a secondary transfer charger 11, and a belt cleaning 10 are disposed on the intermediate transfer belt 8 at a position facing the photoreceptor 1 so as to rotate in the direction of the arrow in FIG. The rotary developing device 5 has four developing devices 19.
Bk, 19C, 19M, and 19Y.
5Bk, 35Y, 35M, and 35C are filled with the developer, and the developing rollers 16Bk, 16C, 16M, and 16Y of the respective developing devices are rotated around the central axis of the rotary developing device so as to be at the developing position. The development is performed by the developer of each developing device.

An image forming process in the image forming apparatus will be described. First, the first color Bk is developed.
At this time, the rotary developing device 5 is located at a position where the developing device 19Bk of Bk faces the photoconductor 1. The surface of the photoconductor 1 that is driven to rotate in the direction of the arrow in the drawing is uniformly charged by the charger 2. Then, a latent image corresponding to the image of the document is formed on the surface of the photoconductor 1 by the exposure device 4 based on an image signal from an image processing unit (not shown). The latent image on the photoreceptor 1 is opposed to the rotary developing device 5 by a developing device 19Bk.
Is developed with the developer supplied from the developing roller 16Bk as a developer carrier of the above to become a visible image. The developed image is transferred onto the intermediate transfer belt 8 by the primary transfer charger 9.
Here, the untransferred toner on the photoconductor is removed by photoconductor cleaning 7.
Thus, the photosensitive member 1 is cleaned from above. When the development of Bk is completed, the rotary developing device 5 rotates 90 degrees,
The next developing unit 16C stops at a position facing the photoconductor.
The same operation as above is repeated, and the remaining developing devices 19C,
19M and 19Y are developed, and a visible image is superimposed and transferred onto the intermediate transfer belt 8, so that four color toners are superimposed on the belt. Subsequently, the four color images on the belt 8 are secondarily transferred to, for example, a transfer sheet 15 as a recording member which is fed at a predetermined timing from a sheet feeding device (not shown) and conveyed to a portion facing the belt 8. The image is transferred by the charger 11. The transfer paper 15 on which the developed image has been transferred
2 to the fixing devices 13 and 14, where the visible image is fixed and discharged. The untransferred toner on the belt 8 after the transfer of the visible image is removed by the belt cleaning 10.
It is cleaned from above. The rotary developing device 5 has four
Developing units 19Bk, 19C, 19M, and 19Y, and toners 31Bk, 31C, and 31 at one end of each developing unit.
M, 31Y containing toner hoppers 37Bk, 37C,
37M and 37Y are provided. The toner 3 is detachable from each toner hopper and supplied to the toner hopper.
The toner cartridges 36Bk, 30C, 30M, and 30Y accommodating 1Bk, 31C, 31M, and 31Y are mounted. Further, the rotary developing device 5 is configured to obtain a drive for rotation from a drive motor 94 described later. Therefore, when the rotary developing device 5 rotates, the four developing devices and the four toner cartridges rotate integrally.
During the rotation of the rotary developing device 5, the toner in each toner cartridge is agitated.

FIG. 2 and FIG. 3 are explanatory diagrams of a developing device used in the image forming apparatus having the above configuration. Each developing unit 19B
k, 19C, 19M, and 19Y have exactly the same configuration, and the description will be made only for the Bk developing device 19Bk. The developing device 19Bk includes a casing having an opening toward the photoconductor 1, and a developing roller 16Bk as a developer carrier for supplying a developer onto the photoconductor 1 from the opening.
And a two-component developer 35Bk composed of toner and carrier
And stirring rollers 17Bk and 18Bk as developer stirring means for stirring the developer in the developing device. As shown in FIG. 3, a toner hopper 37Bk for storing toner to be supplied to the developing device 19Bk and a toner hopper 37 at one end of the rotary developing device 5 in the axial direction of the developing roller.
A toner cartridge 36Bk detachable from Bk is provided. The toner 31Bk contained in the toner cartridge 36Bk is supplied to the toner hopper 37Bk, and further supplied to the toner supply screw 3 in the toner hopper 7.
2Bk supplies the developer 35Bk in the developing device 19Bk. Then, in the developing device 19Bk, the stirring rollers 17Bk and 18Bk replenish the developer 35Bk composed of the toner and the carrier in the casing while mixing and stirring the developer 35Bk on the developing roller 16Bk. After the developer supplied onto the developing roller 16Bk is regulated to a predetermined thickness, the developer is conveyed to a development area opposite to the photoconductor 1 and develops an electrostatic latent image on the photoconductor 1.

This image forming apparatus includes a control unit having a microcomputer configuration for controlling each unit. The control unit has, as main components, a CPU that centrally controls various units by executing various arithmetic processes, a ROM that stores fixed data, and a RAM that is used as a work area that stores variable data. ing.

FIG. 4 is a block diagram of an electrical unit of the image forming apparatus according to the present embodiment. When a main switch 501 of the image forming apparatus is turned on, a DC power supply (PSU) 502 receives supply of AC power from a commercial power supply. Then, the DC power supply voltage is supplied from the DC power supply (PSU) 502 to the control unit 503,
The driving circuit 504 for driving the driving motor 94 is supplied to the inside of the device.

Next, the structure and operation for rotating the rotary developing device 5 when the power supply for the apparatus main body is turned off will be described. As shown in FIG. 4, when the main switch 501 is turned off, the image forming apparatus has a battery 505 dedicated to a rotary drive motor as a rotary drive power supply for supplying power to the drive motor 94.
And a rotary drive power switch 506 as switching means for switching on / off of power supply from the rotary drive motor dedicated battery 505. Also, when the main switch 501 is turned off, the control unit dedicated battery 507 for supplying power to the control unit 503 and the power supply from the control unit dedicated battery 507 are provided so that the control unit 503 functions. Control power switch 50 as second switching means for switching on / off
8 is provided. When the main switch 501 is turned off, the control unit 503 of the image forming apparatus
The control power switch 508 and the rotary drive power switch 506 are both turned on so that power is supplied to the drive motor 94 from the control unit dedicated battery 507 and power is supplied to the drive motor 94 from the rotary drive dedicated battery 505. Thus, even when the main switch 501 is off, the control by the control unit 503 and the execution of the toner stirring by the rotary drive motor can be performed.

In the image forming apparatus according to the present embodiment, a temperature detecting device 33 and a humidity detecting device 34 are provided near the toner cartridge 36Bk. When the power of the apparatus main body is turned off, the toner in the toner cartridge is agitated by rotating the rotary developing device 5 at an optimum timing in accordance with a change in temperature or humidity near the toner cartridge 36Bk. Hereinafter, this operation will be described in detail with reference to the flowchart shown in FIG. When the power of the image forming apparatus is turned off, the apparatus enters the toner stirring mode, and the timer starts counting (t = 0) (S1). Next, the temperature T near the toner cartridge is detected by the temperature detecting device 33 (S2). S
In FIG. 3, according to the detected temperature T, the relationship between the previously obtained temperature T and the optimum stirring operation execution interval (FIG. 12)
It is determined which temperature region T corresponds to, and the stirring operation execution interval t0 at that temperature T is set. Here, the relationship between the temperature T and the optimum stirring operation execution interval is stored as fixed data in the ROM. Then, the process proceeds to the next step depending on whether the power of the image forming apparatus is on or off at this time (S4). If it is in the ON state, the toner stirring mode ends. If it is off, the timer counts up (S5). Next, if the count has not reached the stirring time (if t <t0), the process returns to step S2.
On the other hand, if the count t has reached the stirring time t0 (if t ≧ t0), the toner stirring operation is executed (S7).
After the end, the timer is reset (t = 0) (S8), and the process returns to step S2.

Another example of the operation will be described with reference to the flowchart shown in FIG. In the flowchart shown in FIG. 5, the temperature T near the toner cartridge is detected by the temperature detection device 33 in step 2, but the temperature is changed to the temperature, and the humidity H near the toner cartridge is detected by the humidity detection device 34.
Is detected. Then, in step S3, according to the detected humidity H, from the relationship between the previously obtained humidity H and the optimum stirring operation execution interval (FIG. 13), it is determined which humidity region H corresponds to, and the humidity H is determined. Of the stirring operation at the time t
Set 0. Here, the relationship between the humidity H and the optimal stirring operation execution interval is stored as fixed data in the ROM.

Further, another example of the operation will be described based on the flowchart shown in FIG. In step S2, the temperature T and the humidity H in the toner container are detected. Then, in step S3, based on the detected temperature T and humidity H, it is determined from FIG. 14 (relationship between the temperature T, humidity H and the optimal stirring operation execution interval) which region T and H fall in advance. It is determined that the stirring operation execution interval t0 at the temperature T and the humidity H is obtained.
Set. Here, the relationship between the temperature T, the humidity H, and the optimum stirring operation execution interval is stored as fixed data in the ROM.

As described above, when the power of the apparatus main body is off, the toner is stirred at an optimum time interval according to the temperature and / or humidity in the vicinity of the toner cartridge, or both of them. Can be minimized. In addition, power consumption can be minimized.

In the above embodiment, a full-color image forming apparatus using four colors of yellow, magenta, cyan, and black has been described. However, a so-called multi-color image using black, red, blue, and other colors is used. It can also be applied to forming equipment.

[0023]

According to the first to third aspects of the present invention,
In an image forming apparatus provided with a rotary developing device, regardless of the leaving environment when the power is turned off, the toner in the toner cartridge can be prevented from aggregating and a high quality image can be obtained. There is an excellent effect that the consumption of water can be suppressed.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a schematic configuration of an image forming apparatus according to an embodiment.

FIG. 2 is a schematic diagram of a developing device employed in the image forming apparatus according to the embodiment.

FIG. 3 is a schematic diagram of a developing device employed in the image forming apparatus according to the embodiment.

FIG. 4 is a block diagram of an electrical unit of the image forming apparatus.

FIG. 5 is an example of a flowchart showing control in a toner stirring mode.

FIG. 6 is another example of a flowchart showing control in the toner stirring mode.

FIG. 7 is still another example of a flowchart showing control in the toner stirring mode.

FIG. 8 is a diagram illustrating the relationship between the device standing time and the toner aggregation degree.

FIG. 9 is a diagram illustrating a relationship between a stirring time by rotation of a developing device and a degree of toner aggregation.

FIG. 10 is a diagram illustrating a relationship between a temperature T and the easiness of aggregation of toner.

FIG. 11 is a diagram showing a relationship between humidity T and the easiness of toner aggregation.

FIG. 12 is a diagram showing a relationship between a temperature T and an optimum stirring operation execution interval.

FIG. 13 is a diagram showing a relationship between humidity H and an optimum stirring operation execution interval.

FIG. 14 is a diagram showing a relationship between a temperature T and a humidity H and an optimum stirring operation execution interval.

[Explanation of symbols]

 Reference Signs List 1 photoconductor 5 rotary developing device 16 developing roller 17 first stirring roller 18 second stirring roller 19 developing device 31 toner 32 toner supply screw 33 temperature detecting device 34 humidity detecting device 35 developer 36 toner cartridge 37 toner hopper 94 driving Motor 501 Main switch 502 PSU 503 Control unit 504 Drive circuit 505 Rotation drive battery 506 Rotation drive power switch 507 Control unit battery 508 Control power switch

Claims (3)

[Claims] A plurality of developing units arranged around a rotation axis, and a developing position of any one of the plurality of developing units facing a latent image carrier about the rotation axis. A developing device for rotating and developing the developer, a developer accommodating portion disposed at one end of the developing device and accommodating a developer to be supplied to the developing device, and a detachably attached to the developer accommodating portion. An image forming apparatus comprising a developing device and a developer cartridge which rotates integrally with the developing device, wherein the developing device rotates the developing device to agitate the toner in the toner cartridge when the apparatus main body is turned off. Device rotation means, temperature detection means for detecting the temperature near the toner cartridge, and development device rotation interval control means for controlling the interval of the rotation of the development device performed by the development device rotation means based on the detected temperature. Equipped An image forming apparatus comprising: 2. A plurality of developing devices are arranged around a rotation axis, and any one of the plurality of developing devices is moved to a developing position facing a latent image carrier about the rotation axis. A developing device for rotating and developing the developer, a developer accommodating portion disposed at one end of the developing device and accommodating a developer to be supplied to the developing device, and a detachably attached to the developer accommodating portion. An image forming apparatus comprising a developing device and a developer cartridge which rotates integrally with the developing device, wherein the developing device rotates the developing device to agitate the toner in the toner cartridge when the apparatus main body is turned off. Device rotation means, humidity detection means for detecting humidity in the vicinity of the toner cartridge, and development device rotation interval control means for controlling the interval of rotation of the development device performed by the development device rotation means based on the detected humidity. Equipped An image forming apparatus comprising: 3. A plurality of developing devices are arranged around a rotation axis, and any one of the plurality of developing devices is moved to a developing position facing the latent image carrier about the rotation axis. A developing device for rotating and developing the developer, a developer accommodating portion disposed at one end of the developing device and accommodating a developer to be supplied to the developing device, and a detachably attached to the developer accommodating portion. An image forming apparatus comprising: a developing device; and a toner cartridge that rotates together with the developing device, wherein the developing device rotates the developing device to agitate the toner in the toner cartridge when the apparatus main body is turned off. Rotating means, a temperature detecting means for detecting a temperature near the toner cartridge, a humidity detecting means for detecting humidity, and an interval between rotation operations of the developing device performed by the developing device rotating means based on the detected temperature and humidity. Control And a developing device rotation interval control unit.