JP2000029298A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a toner from being solidified due to its own weight in a toner container and to always steadily replenish the toner to a developing device from the toner container in an image forming device having a toner supply system in which a screw pumps is provided to the toner outlet of the toner container storing the toner to be supplied to the developing device, the toner is forcibly fed out from the inside of the toner container into a toner transfer tube connected to the developing device and the toner in the container is forcibly moved to the toner outlet by means of an axially-rotating carrying screw provided along the internal bottom-face of the toner container. SOLUTION: An agitator 311 for stirring a toner 400 in a toner container 302 is provided with the function of carrying the toner 400 in the direction opposite to the direction is which a carrying screw 312 carries the toner 400. Thus, the toner 400 accumulating at the end on one side is moved toward the opposite side as shown by the arrow, to suppress the toner from excessively accumulating at the end on one side of the toner container 302.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device provided with a toner replenishing device for replenishing toner from a remote position through a toner transfer pipe to a developing device for visualizing a latent image on an image carrier to form a toner image. The present invention relates to an image forming apparatus such as a photographic copying machine, a facsimile machine, a printer, and a multifunction peripheral thereof.

[0002]

2. Description of the Related Art Conventionally, there has been provided an image forming apparatus which is provided with a toner replenishing device which is formed separately from a developing device, and which supplies toner from the toner replenishing device to a toner storing portion of the developing device through a toner transfer pipe. Devices are known. In this type of image forming apparatus, a screw pump is provided at a toner outlet of a toner container attached to a toner replenishing device to forcibly send toner from the toner container to a toner transfer pipe, and the toner container has a bottom surface inside the container. Is provided, and the toner in the container is forcibly moved to the toner outlet side, that is, the inlet side of the screw pump by the conveying screw, so that the toner is stably supplied from the toner container to the developing device. At the same time, the toner in the toner container can be used with as little waste as possible.

[0003]

However, in order to efficiently introduce the toner in the toner container into the screw pump, the amount of toner transported by the transport screw is set to be larger than the amount of toner delivered by the screw pump. Because of the necessity, the toner easily accumulates at one end of the toner container (see FIG. 4). For this reason, an excessive pressure is applied to the toner near the toner outlet of the toner container due to the weight of the accumulated toner itself and the transport pressure of the transport screw. As a result, the toner in the vicinity of the toner outlet solidifies, and the toner is not smoothly introduced into the screw pump. Therefore, there is a problem that the toner supply to the developing device becomes insufficient and the image formation is hindered. This problem becomes more significant as the size of the toner container increases. Therefore, a problem to be solved by the present invention is to provide a screw pump at a toner outlet of a toner container containing the toner to be supplied to the developing device and forcibly send the toner from the inside of the toner container to a toner transfer pipe connected to the developing device, In an image forming apparatus having a toner supply system in which toner in a container is forcibly moved to a toner outlet side by an axially rotating conveying screw provided along the inner bottom surface of the toner container, toner coagulation in the toner container is performed. It is an object of the present invention to provide an image forming apparatus capable of forming an image while always stably supplying toner from a toner container to a developing device.

[0004]

According to the first aspect of the present invention, there is provided a developing device for visualizing a latent image on an image carrier with toner, and supplying the latent image to the developing device. A toner container containing toner; a powder transfer pump provided at a toner outlet of the container for transferring toner from the toner container to the developing device through a toner transfer pipe; An axially rotating transport screw provided along the inner bottom surface of the container to move the toner container to the side, and an axially rotating agitator provided along the transport screw to agitate the toner in the toner container. In the image forming apparatus, the agitator is provided with a conveying member that conveys the toner in a direction opposite to a direction in which the conveying screw conveys the toner. Is characterized in that so as to suppress the toner is excessively accumulated in the side end portion. According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the agitator has a rotation axis substantially parallel to a rotation axis of the transport screw, and a coil circling the outer circumference of the rotation axis. The use of an agitator formed with a transfer member in the shape of an arrow suppresses an increase in the number of components due to the provision of the transfer member, and also suppresses an increase in load torque acting on the agitator.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a copying machine showing an example of an image forming apparatus to which the present invention is applied. This copying machine includes an image forming unit A and a paper feeding unit B. The image forming unit A irradiates light to the original 101 placed on the contact glass 101 with the original surface down, and irradiates the original 101 with light. A reading unit 103 for reading reflected light, a writing unit 104 for outputting a laser beam based on image information read by the reading unit 103, and a photosensitive drum 110 serving as a latent image carrier for outputting a laser beam emitted from the writing unit 104 Mirrors 105 to 109 for guiding the surface of the photosensitive drum 110 to a light writing position, and a charger 11 for charging the surface of the photosensitive drum 110
1, a developing device 112 for developing the electrostatic latent image formed by irradiating the laser beam onto the photosensitive drum 110 after the charging process with toner, and a toner replenishing device for supplying the developing device 112 with the toner 400 A registration roller 115 for feeding the transfer paper 114 fed from the paper supply unit B at a predetermined timing;
The transfer paper 114 sent out of the photosensitive drum 11
A transfer device 116 for transferring the toner image formed on
A fixing unit 117 for fixing the transferred toner image to the transfer paper 114, a discharge tray 118 for receiving the transfer paper 114 subjected to the fixing processing and discharged, and a photosensitive drum 110 after the transfer processing is completed. A cleaning unit 119 for cleaning in preparation for the next copying process is generally configured. The developing device 112 and the toner replenishing device 113 are connected to each other by a toner transport pipe (toner transport tube) 500 made of a flexible member.
13 is supplied to the developing device 112 through the toner transfer pipe 500.

FIG. 2 is an enlarged sectional view of the developing device 112, and FIGS. 3, 4 and 5 show the toner replenishing device 1 respectively.
13 is an overall perspective view, an overall side sectional view, and a partially cutaway view of FIG. The toner supply device 113 includes a supply device main body 301,
A toner container 302 mounted on and integrally fixed to the supply device main body 301. As shown in FIG. 3, a guide rail 303 is provided on both sides of the replenishing apparatus main body 301. It can be withdrawn. The guide rail 303 engages with a guide rail (not shown) on the device main body side to guide the supply device main body 301. Then, with the toner supply device 113 pulled out, the toner supply port of the toner bottle or bag (not shown) containing the toner 400 is connected to the toner supply port 3 provided at one end of the upper surface of the toner container 301.
By setting to 05, the toner 400 can be replenished to the toner container 302. Toner container 3
An air filter 306 is provided at the other end of the upper surface of the air filter 01. The air filter 306 prevents the toner 400 from scattering outside the toner container 302 when refilling the toner, and allows the toner container 30 to be refilled quickly.
It has a function to extract only air from 2. Toner supply port 30
5 to the toner 400 replenished in the toner container 302
4 and 5, the power of the drive motor 307 is transmitted through the gear trains 308 to 310 and is agitated by the agitator 311 rotating around the shaft.
07 is transmitted to the powder pump unit 600 connected to the toner outlet of the toner container 302 by the transport screw 312 which is transmitted through the gear 308 and rotates around the shaft.

FIG. 6 shows the structure of the powder pump unit 600. As the powder pump unit 600, a well-known screw pump called a so-called mono pump is used. As shown in the figure, the powder pump unit 600 includes a helical rotor 31 substantially coaxially connected to the conveying screw 312.
3, a stator 314 which is a fixing member having a spiral groove therein and arranged so as to enclose the rotor 313, and a holder 315 for holding the stator 314, and the rotor 313 together with the transport screw 312 in the toner container 302.
Is rotated, the toner 400 sent by the conveying screw 312 is transferred to the rotor 313 and the stator 31.
It is configured to feed in the axial direction through the space between the four. Stator 314 is made of an elastic material such as rubber. The distance between the outer peripheral surface of the stator 314 and the inner peripheral surface of the holder 315 is 1
A gap of about mm is provided.
No. 5 communicates with a toner discharge section 316 provided at the tip. Further, the air pump 31 is provided in the supply device main body 301.
7 is provided, and an air discharge port of the air pump 317 is connected to an air supply port 319 provided at an upper portion of the holder 315 via an air supply pipe 318. Therefore, when the air pump 317 is operated, air is blown into the gap from the air supply port 319 and flows to the toner discharge unit 316 through the gap. And rotor 3
The toner 400 that has flowed out between the space 13 and the stator 314 is fluidized by an air flow, is discharged from the toner discharge unit 316 in a mixed state with air, and is sent to the developing device 112 through the toner transfer pipe 500.

The mixture of the air and the toner 400 sent to the developing device 112 through the toner transfer pipe 500 is
As shown in FIG. 2, the air and the toner 400 are separated by a funnel-shaped toner separation unit 201 provided at an upper portion of the main body of the developing device 112. Then, the toner 400 descends while helically moving by gravity and enters the main body of the developing device 112, and the air rises and is discharged from the filter 205 above the toner separating unit 201. The toner 400 that has fallen from the toner separating unit 201 is agitated by the stirring screws 202 and 203.
Is stirred with the magnetic carrier to form a two-component developer triboelectrically charged in a direction opposite to that of the magnetic carrier.
To be subjected to a developing process. In order to efficiently transfer the toner 400 from the toner container 302 to the developing device 112 through the toner transfer pipe 500 by the toner supply device 113 configured as described above, the rotor 313 and the stator 314 of the powder pump unit 600 are used. It is necessary that the toner 400 in the toner container 302 efficiently enters the narrow gap. To this end, the toner transport amount of the transport screw 312 is reduced by the powder pump unit 6.
It is necessary to set the amount of toner to be larger than the amount of toner to be transmitted by 00, that is, the amount of toner supplied to the developing device 112.

For this reason, as shown in FIG. 4, the extra toner 400 gradually gathers at one end of the toner container 302 (the left end in the example of FIG. 4). At this time, if the amount of toner is small, there is no problem. However, if the amount of toner is large, the lower toner 400 is compacted by the weight of the accumulated toner 400 itself. Solidification is likely to occur in the vicinity, and the conveying screw 312 and the agitator 311 may be locked by the solidified toner. Therefore, in the present invention, in order to prevent such a problem, the toner 400 is transported to the agitator 311 for stirring the toner 400 in the toner container 302 in a direction opposite to the direction in which the transport screw 312 transports the toner 400. By moving the toner 400 collected at one end to the opposite side (right side) as shown by the arrow in FIG.
Toner is prevented from excessively collecting at one end of the toner container 302.

FIGS. 7 to 9 show an embodiment of an agitator having the above functions. The agitator 311 shown in FIG. 7 has a rotating shaft 51 provided with the gear 310 substantially parallel to the axis of the conveying screw 312, and a U-shaped stirring member 53 provided integrally with the rotating shaft 51. Further, as a conveying member for conveying the toner 400, a spiral conveying blade 52 is provided on the outer peripheral portion of the rotating shaft 51. Agitator 311
May be smaller than the transfer screw 312, so that the transfer blade 52 can be partially provided as shown in FIG. 7 or the outer diameter of the transfer blade 52 can be reduced. Such a structure is also effective in reducing the load torque of the agitator 311. Also, instead of the U-shaped stirring member 53 shown in FIG. 7 or in addition to the stirring member 53, as shown in FIG. 8, a rod-shaped protruding radially from the outer peripheral surface of the rotating shaft 51 between the adjacent transport blades 52. Ribs 54
May be provided. When the increase in the load torque of the agitator 311 due to the provision of the spiral conveying blades 52 becomes a problem, as shown in FIG. 9, the outer peripheral portion of the rotating shaft 51 is used as a member having both the stirring function and the conveying function. It is effective to integrally form a coil-shaped conveying member 55 that circulates around this. If such a structure is adopted, the agitator 3
11 not only reduces the load torque but also reduces the number of parts.

[0011]

As described above, the present invention has the following excellent effects. According to the first aspect of the present invention, the toner is transported to the agitator, which is provided along the transport screw to stir the toner in the toner container, and rotates in the direction opposite to the direction in which the transport screw transports the toner. By providing the function, it is possible to prevent toner from solidifying at one end of the toner container and prevent toner coagulation, so that image formation can be performed while constantly supplying toner from the toner container to the developing device stably. . According to the second aspect of the present invention, there is used an agitator having a rotation axis substantially parallel to the rotation axis of the conveyance screw, and forming a coil-shaped conveyance member around the rotation axis on the outer periphery of the rotation shaft. By doing so, it is possible to suppress an increase in the number of components and an increase in load torque acting on the agitator due to the provision of the transport member in the agitator.

[Brief description of the drawings]

FIG. 1 is a sectional view of a copying machine showing an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is an enlarged sectional view of the developing device shown in FIG.

FIG. 3 is an overall perspective view of the toner supply device shown in FIG.

FIG. 4 is an overall side sectional view of the toner supply device shown in FIG.

FIG. 5 is a partial cutaway view of the toner supply device shown in FIG.

FIG. 6 is a partial sectional view showing a configuration of the powder pump unit shown in FIG.

FIG. 7 is a perspective view of a main part of an agitator showing an example of an embodiment of the present invention.

FIG. 8 is a perspective view of a main part of an agitator showing an example of an embodiment of the present invention.

FIG. 9 is a perspective view of a main part of an agitator showing an example of an embodiment of the present invention.

[Explanation of symbols]

51: rotating shaft, 52 transport blade (transport member), 53: stirring member, 55: transport member, 110: photosensitive drum (latent image carrier), 112: developing device, 113: toner replenishing device, 301: replenishing device Main body, 302: toner container, 30
6: Filter, 311: Agitator, 312: Conveying screw, 313: Rotor, 314: Stator, 315: Holder, 316: Toner discharge section, 317: Air pump,
318: Air supply pipe, 319: Air supply port, 4
00: toner, 500: toner transfer pipe (toner transfer pipe), 600: powder pump unit.

Claims (2)

[Claims] 1. A developing device for visualizing a latent image on an image carrier with toner, a toner container containing toner to be supplied to the developing device, and a toner transfer pipe from the toner container to the developing device. A powder transfer pump provided at a toner outlet of the toner container to transfer the toner, and an axial rotation provided along an inner bottom surface of the toner container to move the toner in the toner container to the toner outlet side. An image forming apparatus comprising: a conveying screw to be rotated; and an agitator which is provided along the conveying screw to agitate the toner in the toner container. The agitator includes a toner in a direction opposite to the conveying screw. An image forming apparatus provided with a conveying member for conveying the image. 2. The agitator according to claim 1, wherein the agitator has a rotation axis substantially parallel to a rotation axis of the transfer screw, and a coil-shaped transfer member that rotates around the rotation axis is formed on an outer peripheral portion of the rotation shaft. The image forming apparatus according to claim 1.