JPH0367283A - developer supply device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus equipped with an electrophotographic image forming mechanism, and more particularly to an improvement of a developer replenishing device for replenishing additional toner to a developing device.

(Conventional technology) A copying machine equipped with an electrophotographic image forming mechanism.

In image forming devices such as printers and facsimile machines, an electrostatic latent image is formed by irradiating reflected light from the original and other optical original information onto a photoconductor, and a developing device then forms an electrostatic latent image on this electrostatic latent image. Toner powder is applied and visualized, then transferred to transfer paper, and finally fixed to complete the image forming process.

A two-component developing device has a toner tank containing a mixture of carrier and toner powder inside, and this toner tank houses a developing roller that applies the toner onto the photoconductor, an agitation mechanism, etc. There is.

If the toner in the tank is consumed by toner application by the developing roller, there will be insufficient toner to adhere to the carrier, resulting in a decrease in developing ability.

A replenishment means is required to keep the toner in the toner tank constant.

Such a replenishing means is one in which a toner hopper (developer accommodating section) is placed in the vicinity of the toner tank, and a predetermined amount of toner is replenished into the tank by rotation of a toner replenishing roller inside the toner hopper. exists. The reason why the replenishment means is placed close to the toner tank is that it is easier to maintain the appropriate amount of replenishment in the toner tank. It is difficult to secure space, and if a large-capacity toner hopper is forcibly installed, the degree of freedom in layout of other units to be installed around the developing device will be greatly reduced. On the other hand, unless a large-capacity toner hopper is provided, users who make a large amount of copies will have the problem of running out of toner and increasing the number of toner replenishments.

From this point of view, Japanese Patent Application Laid-Open No. 55-135873 proposes that a small-capacity toner hopper is arranged inside the toner tank, a large-capacity toner hopper is arranged at a sufficient distance from the toner tank, and The hoppers are connected by a toner transport to replenish toner from one large capacity hopper to the other hopper, and the large capacity hopper is vibrated to prevent toner bridging and caking within the hopper. A configuration is disclosed. Further, a spiral member made of a flexible material is disposed within the toner transport to facilitate toner transport. According to this configuration, it is possible to install a large-capacity toner hopper at a position sufficiently away from the developing device (dead space) without making unreasonable use of the limited space around the developing device.

A transfer member such as a spiral member or a speed chain is disposed within the toner transport (transfer path), and is driven by a drive source such as a motor to replenish toner from the large capacity hopper to the other hopper. ing. The motor is controlled based on the detection signal from the level detector installed in one or both hoppers, but as mentioned above, the large-capacity toner hopper is placed a predetermined distance from the other hopper. Toner clogging and toner sticking within a long transport path are likely to occur, and no countermeasures have been taken in the event that these abnormalities occur.

If clogging or sticking of toner occurs in the transfer path that replenishes toner from the large-capacity hopper to the other hopper, the transfer member such as the spiral member may be damaged, or the motor that is the drive source may be overloaded. This increases the risk of serious problems such as damage to the coil (coil seizure, etc.).

Next, if the amount of toner supplied from a small-capacity toner hopper to the developing device and the amount of toner supplied from a large-capacity hopper to the other hopper are not balanced, the following problem occurs.

That is.

(a) When the amount of toner supplied from the large-capacity hopper is greater than the amount of toner supplied to the developing device.

1 in this case? The small-capacity toner is oversupplied to the hopper, and the toner is backed up in the small-capacity hopper more than necessary, causing problems such as damage to the toner transfer member and the like.

(In the case of bl: amount of toner supplied from the large-capacity hopper vs. amount of toner supplied to the developing device.

In this case, there will be an insufficient supply of toner to the small-capacity hopper, and there will also be an insufficient supply of toner to the developing device, causing problems such as a decrease in image density due to a decrease in toner concentration or carrier adhesion.

Furthermore, despite the trend toward smaller image forming devices,
As far as the developing section is concerned, the toner storage device (
Hopper> is larger, which may cause layout problems,
Problems include poor handling.

(Objective of the Invention) The present invention provides a toner bank that maximizes the use of space within an electrophotographic copying machine while preventing accidents such as damage to the motor caused by toner clogging in the transfer path as described above. The purpose of this is to maximize the toner storage capacity.

Another object of the present invention is to eliminate various problems caused by an imbalance between the amount of toner supplied from the toner hopper to the developing device and the amount of toner supplied between the hoppers.

This makes it possible to significantly reduce the number of toner replenishments, which had previously been a major burden on the user, and also allows the service person to replenish toner when the service person visits (PM, EM). It is also possible to completely eliminate toner replenishment work.

(9, Bright Structure) In order to achieve the above object, the developer replenishing device of the present invention includes a first developer accommodating device that replenishes developer to a developing device, and a first developer accommodating device that is disposed at a spaced apart position from the developing device. In the developer replenishing device, the developer replenishing device has a second developer accommodating device provided therein, and an articulated conveying section that conveys and supplies developer from the second developer accommodating device to the first developer accommodating device. The present invention is characterized in that a torque limiter mechanism is provided between the driven shaft of the conveying member and the drive shaft that drives the driven shaft of the conveying member.

Further, one end of the driven shaft of the conveying member of the present invention is connected to the first
A cross-linking prevention member that extends toward the developer storage device and prevents cross-linking of the toner in the first developer storage device is fixed to the extended end of the driven shaft, and when the cross-linking prevention member is rotated, the cross-linking prevention member is fixed to the extended end of the driven shaft. It is characterized in that the torque limiter mechanism described in @ is activated according to the resistance received from the toner.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIGS. 1 and 2 are explanatory diagrams showing the configuration of an electrophotographic copying machine using a developer replenishing device as a preferred embodiment of the present invention, and the configuration of the peripheral portion of a light source.

This electrophotographic copying machine scans an original document 12 placed on a contact glass 15 in the direction of arrow a using a light source IO, and uses optical systems such as mirrors and lenses to direct the reflected light from the original document 12 to a photosensitive drum. Lead to 2.

The surface of the photoreceptor drum 2 is charged in advance to a high voltage by the charger I and rotates in the direction of the arrow in synchronization with the scanning, so that an electrostatic latent image is formed on the photoreceptor drum 2 by exposure to the reflected light. is formed.

The electrostatic latent image is in the developer bag g! . Next, the recording paper is transferred to the conveyor belt! 6, the sheet is conveyed to a fixing device (not shown), and after being fixed, it is discharged.

Reference numeral 7 is a cleaning device for removing toner remaining on the photosensitive drum 2, and 9 is a sensor for detecting toner concentration.

The toner in the developing bag rIL3 decreases when it is supplied to the photoreceptor drum 2, and as the toner becomes depleted, the density of the visible image on the photoreceptor drum decreases.
The amount of toner in the developing bag [3] is controlled by detecting the toner density of the visible image.

As shown in FIG. 2, this toner density control method involves scanning the image of the reference density plate II provided on the tip side of the contact glass 15 (on the left side of the drawing), and applying the reflected light from the reference density plate to the photoreceptor drum. The toner density detection sensor 9 detects the density of the developed image by irradiating the toner to form an electrostatic latent image. Let the output of the sensor 9 be v5F, and let the sensor output when erasing the front and rear of the visible image of the base lfi scale plate be v3o, and v sp
When the value of /v becomes larger than a predetermined reference value, the toner replenishing roller 5 of the developing device 3 is driven a predetermined number of times or for a certain period of time to supply toner to the sleeve side.

A first developer accommodating device 16 is removably disposed close to the developer bag rit3, and a second developer accommodating device is located at a predetermined distance away from the first developer replenishing device (dead space of the copying machine body). A mounting fi17 is provided. The second developer storage device 17 is configured as a large-capacity toner storage container.

The second developer accommodating device 17 and the first developer accommodating device 16 are connected by a connecting conveyance section 20, that is, as shown in FIG. Part 1
6.17 is a cross-sectional view showing the connection structure of the connection conveyance section 2.
0 consists of an outer cylinder 21 and a conveyance screw (conveyance member) 22 disposed to penetrate the inside of the outer cylinder 21 in the axial direction. The rotation of the screw 22 causes the toner 23 in the second developer storage device 17 to be transferred to the first developer storage device m! 16.

The conveyance screw 22 is driven by a motor (not shown), and the motor is driven by a control unit such as a microcomputer (not shown).

That is, the control unit includes an input/output interface, a CPU, an RO
The ROM includes a toner storage device M, a RAM, and the like, and the ROM stores control information for turning the screw 22 ON and OFF based on detection information from a toner amount detection sensor provided in the storage device.

Inside the first developer storage device ff11B, there is a member +
8 is rotatably arranged. The crosslinking prevention member 18 is a member whose base end is supported by a shaft 32 that rotates integrally with the drive torque from the shaft (driven shaft) 30 of the screw 22, and is housed in the first developer storage device I6. Stir the toner.

At the input end 30a of the driven shaft 30 of the screw 22, a drive shaft 35 integral with an input gear 34 connected to the output shaft of a motor (not shown) is disposed coaxially and relatively rotatably. A torque limiter mechanism 40 is engaged with the outer periphery of the driven shaft 30 .

The torque limiter mechanism 40 is as usual.

In steady state, torque is transmitted from the driving side to the driven side, but when an overload is applied to the driven side, a mechanism is used that operates to cut off the transmission of driving torque from the driven side. , in this embodiment, between the outer circumferential surface of a sleeve 42 that is integrated with the driven shaft 30 and is loosely attached to the outer circumference of the drive shaft 35, and the outer circumferential surface of a sleeve 44 that is integrated with the outer circumference of the drive shaft 35. , has a structure in which a coil spring 45 is wound. coil spring 4
At all times, the driven shaft 30 and the drive shaft 35 are fixed with a predetermined pressure force. When toner is not clogged or stuck in the articulated conveying section 20 (normal state), the coil spring 45
can transmit drive torque from the drive shaft 35 to the driven shaft 30. Therefore, the screw 22 can rotate and realize the toner conveying function. When clogging or sticking of toner occurs in the articulated conveyance section 20, the load applied to the driven shaft increases, so the driven shaft 30 causes relative rotation between the driven shaft 30 and the drive shaft 35.
rotation is delayed), and the coil spring 45 is in the expanded state (
(sliding on the sleeve 42), and the driving force from the drive shaft 35 cannot be transmitted to the driven shaft.

Therefore, the screw 22 cannot rotate, and the toner conveying function cannot be realized.

Next, when the driven shaft 30 integrated with the screw 22 and the shaft 32 are connected, the amount of toner in the first developer storage device 16 can be determined based on the rotational torque of the crosslinking prevention member 18.

That is, when the amount of toner in the first developer accommodating device I6 is small, the rotational torque of the crosslinking prevention member becomes small, so that the conveyance screw 22 can rotate, and the first developer is transferred from the second developer accommodating device 17. Toner can be transferred to the agent storage device 16.

Next, when the amount of toner in the first developer accommodating device 16 is large, the rotational torque of the crosslinking prevention member becomes large, so the conveyance screw 22 becomes unable to rotate due to the operation of the torque limiter, and the second developer It becomes impossible to transfer toner from the storage device +7 to the first developer storage device 16.

In this way, when there is a sufficient amount of toner in the first developer storage device 16, the amount of toner in the first developer storage device 16 decreases by replenishing the developing device and falls below a predetermined level. Until then, the transmission of the driving force to the conveying screw 22 remains cut off. When the amount of toner in the first developer accommodating device 16 exceeds a predetermined level, the torque limiter is turned on again to transmit driving force to the screw, and replenishment of toner into the first developer accommodating device 16 is started.

The strength of the elastic force of the coil spring 45 determines to what extent the toner in the first developer storage device t16 has increased to stop the supply of toner. Therefore, by setting the strength of the coil spring 45 to a predetermined value, the amount of toner in the first developer storage device 6 can always be appropriately set. For example, the toner storage capacity can be maximized by providing a toner bank that maximizes the space inside the electrophotographic copying machine while preventing accidents such as damage to the motor caused by toner clogging in the transfer path. can be realized.

Further, various problems caused by an imbalance between the amount of toner supplied from the toner hopper to the developing device and the amount supplied between the hoppers can be solved.

The number of toner refills, which used to be a major burden, can be significantly reduced, and the toner replenishment work on the user's side is completely eliminated by having the service personnel replenish toner when the service personnel visit (PM, PM). You can also do that.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a developer replenishing device as a preferred embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of the peripheral area of the light source, and FIG. It is a sectional view of a connection conveyance part which connects these. 3... Developing device 16... First developer storage device rii
17... Second developer replenishment device 2 20... Continuous conveyance unit 22... Conveyance screw 25... Toner amount detection sensor

Claims (2)

[Claims] (1) A first developer accommodating device that replenishes developer to the developing device, a second developer accommodating device disposed at a position apart from the developing device, and a second developer accommodating device that supplies developer to the developing device; The first
In a developer replenishing device having a connecting conveyance section that conveys and supplies developer to a developer storage device, a driven shaft of a conveyance member constituting the connected conveyance section and a drive shaft that drives the driven shaft of the conveyance member are connected to each other. A developer replenishing device characterized by having a torque limiter mechanism disposed therebetween. (2) One end of the driven shaft of the conveying member according to the first claim extends toward the first developer storage device, and the extended end of the driven shaft has a portion inside the first developer storage device. A developer replenishing device characterized in that a crosslinking prevention member for preventing crosslinking of toner is fixedly attached, and the torque limiter mechanism is operated in response to resistance received from the stored toner when the crosslinking prevention member rotates.