JPH0980882A - Toner replenishment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost, compact, simple-structured toner-replenishment device capable of continuously replenishing a developing part with a fixed amount of toner. SOLUTION: The toner replenishment device is equipped with a toner storage container 14 having a toner discharge port 14d formed in the central part of one end of the cylindrical container in its axial direction, a container holding means 18 which holds the toner storage container almost horizontally in the state of being able to introduce toner to the toner introducing part of an image forming device from the toner discharge port, and a rotation driving means 13 which is held by the container holding means 18 and rotates the toner storage container around the central axis of the cylinder in its longitudinal direction. In the toner replenishment device, the container holding means 18 is provided with an opening 18a for introducing the toner, sent out from the toner discharge port of the toner storage container, to the toner introducing part, and the size of the opening is allowed to be changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner replenishing device for a developing device of an electrophotographic image forming apparatus, and in particular, it keeps replenishing a certain amount of toner to a developing portion while having a low cost, compact and simple structure. Toner replenishing device that can be used.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic process such as a copying machine, a facsimile machine, a printer, etc.
A developing device that visualizes the electrostatic latent image formed on the image carrier is used. This developing device supplies a toner to the image carrier and a developing roller that agitates the toner and at the same time. A stirring means for supplying the toner to the developing tank, a developing tank accommodating these means, and a toner replenishing device for replenishing the toner in the developing tank are provided. The most common developing device and toner replenishing device have a structure as shown in FIG. In FIG. 8, reference numeral 30 is a photosensitive drum, 50 is a developing device, 49 is a developing roller, 51 is a paddle roller, 52 is a developing tank for accommodating them, and the developing device 50 accommodates a toner. The toner cartridge 45 and the toner hopper portion 47 for supplying the toner are provided, and the toner in the toner cartridge 45 is supplied to the toner hopper portion 47 by the agitator 46. Once the toner is replenished to the toner hopper section 47, the toner replenishing roller 48 keeps the toner replenishing amount to the developing section 50a as constant as possible, and the toner concentration in the developing section 50a becomes constant. This is because.

[0003]

However, in the above-mentioned conventional toner replenishing device, the toner cartridge 4 is used.
5, the toner is temporarily supplied to the toner hopper portion 47 from the two stages, that is, two spaces of the toner cartridge 45 and the toner hopper portion 47 are provided, and the agitator 46 and the toner are provided. Since a drive system must be provided for each of the replenishment rollers 48, there is a problem that the device becomes large and the cost increases. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a toner replenishing device having a low cost, compact size, and a simple structure capable of continuously replenishing a constant amount of toner to a developing section. To do.

[0004]

According to a first aspect of the present invention, there is provided a toner storage container having a toner discharge port formed in a central portion of one end side in an axial direction of a cylindrical container, and an image forming apparatus from the toner discharge port. The container holding means for holding the toner storage container in a substantially horizontal direction and the toner storage container held by the container holding means around the central axis thereof in a state in which the toner can be introduced into the toner introduction part. Having a rotation driving means for rotating the toner
In the replenishing device, the container holding means is provided with an opening for introducing the toner discharged from the toner discharge port of the toner storage container into the toner introducing portion, and the size of the opening is variable. I made it possible. Therefore, low cost,
Compact and simple structure, but a fixed amount of toner
Can be continuously supplied to the developing section. According to the second aspect of the present invention, since a plurality of toner scraping members are provided in the container holding means for holding the toner storage container and rotating integrally with the toner storage container, a large number of toners can be replenished at one time. Instead, toner can be replenished little by little to reduce unevenness and variation in toner density in the developing device, to sufficiently stir and start up the toner, and prevent background stains and toner scattering. Claim 3
In the invention described above, the size of the opening for introducing the toner into the toner introducing portion is changed according to the amount of toner in the toner accommodating container. , The discharge amount from the toner discharge port varies,
It is possible to prevent background stains, toner scattering, or reduction in image density due to variations in the amount of toner supplied to the developing device, and always obtain a stable image density. According to the invention of claim 4, since the size of the opening is reset to the initial state when the toner storage container is replaced, the condition is automatically changed by the replacement of the toner storage container, and a stable image density is always obtained. can get.

[0005]

1 is a vertical cross-sectional view showing a schematic structure of an image forming unit including a developing device using a toner replenishing device of a position embodiment of the present invention, and FIG. 2 is a perspective view thereof. , Fig. 3
FIG. 3 is an external view of a process cartridge unit. The image forming system will be described with reference to FIGS. This image forming system is roughly divided into a process cartridge portion and a toner replenishing device. The process cartridge unit includes a photosensitive drum 1, a charger 2, an exposure unit 3, a developing device 4, a transfer device 5, a cleaning device 6, a charge eliminating unit 7, and the like. The toner supply device
A toner storage container 14 that is detachably attached to a case 18 that is connected to the developing device 4, and a receiving member 18A that is provided at one end of the case 18 and rotatably supports the head (right end) of the toner storage container. It has a handle 26 and the like which is supported so as to be movable up and down with respect to the receiving member 18A, and has been closed by the cap 15 by pushing down the handle 26 with the toner storage container 14 attached to the case 18. The discharge port 14d of the container 14 is opened, and the toner can be supplied to the developing device side.

Photosensitive drum 1 which is rotationally driven in the direction of the arrow.
Has a surface potential of 0 when it is neutralized by the neutralization light 7.
Averaged to a reference potential of -150V. Subsequently, after being charged by the charging roller 2 and having a surface potential of about −1100 V, the surface potential of the portion (image portion) where the light reflected by the document is exposed by the exposure portion 3 is exposed to 0. ~ -29
It becomes 0 V, and an electrostatic latent image is formed there. Since a bias of about -800 V is applied to the developing roller 4 facing the surface of the photoconductor, the toner on the developing roller 4a of the developing device 4 adheres to this latent image portion. The photoconductor drum 1 on which the toner image is formed is rotated and moved, and the transfer paper P is sent from the paper feeding unit (not shown) at such a timing that the front end of the paper and the front end of the image coincide with each other on the transfer roller 5. Transfer
The toner image on the surface of the photoconductor is transferred to the transfer paper by applying a transfer bias having a polarity opposite to that of the toner from the printer 5. The transfer paper P that has received the transfer is sent to a fixing unit (not shown),
The toner is fused to the transfer paper by heat and pressure and discharged as a copy. On the other hand, the residual toner remaining on the photoconductor drum 1 is scraped off by the cleaning blade 6a, and then the photoconductor drum 1 is neutralized by the static elimination light 7 to eliminate the residual toner. Then, the next image forming process is started again. The above is the basic operation. The photoconductor drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are housed in a photoconductor case C having an integral structure. The residual toner collected by the cleaning device 6 is conveyed in the axial direction by the toner conveying coil (spiral screw) 8 and is sent to the recycling toner conveying section, where the recycling belt 9 causes the agent stirring screw 11 to move. The toner is sent to the (developer stirring section) and the toner is recycled.

Next, the developing device 4 in the process cartridge will be described with reference to FIGS. Developing roller 4
Reference character a has a fixed shaft in which a magnet with five poles is arranged, and the outer peripheral portion is composed of a non-magnetic rotating member. By rotating the non-magnetic rotating member, the developer moves on the developing roller 4a. The developer is a two-component developer composed of a small ferrite material called a carrier and a toner. The stirring screw 11 circulates and stirs the developer, whereby the toner has an electric charge, and the toner adheres to the carrier and is carried to the surface of the photoconductor so that it can be attached to the photoconductor drum 1. Of the developer, the carrier circulates, but the toner adheres to the image portion on the photoconductor and is consumed. Therefore, it is necessary to appropriately replenish the toner. Further, in order to keep the amount of the developer supplied to the photosensitive drum 1 constant, a doctor blade 10 for regulating the developer on the developing roller 4a is provided. Reference numeral 12 is a toner introducing portion of the developing device 4 in the process cartridge.

Next, the toner replenishing device will be described. FIG. 4 is an external perspective view of the toner replenishing device, FIG. 5 is a component configuration diagram of the toner replenishing device, and FIGS. 6 and 7 are cross-sectional views showing the configuration of each member held by the receiving member 18A. The toner replenishing device includes a drive unit 13, a toner storage container 14, a cap 15, a bottle holding member 16, a scraping member 17, a toner replenishing device case 18, a collet chuck 21, a cylindrical case 22, a shaft member 23, a handle 26, and Coil spring 28
It is composed of various parts. The outline of the operation of this toner supply device is as follows. That is, when the toner storage container 14 is attached to the case 18, the toner storage container 1
When the handle 26 is rotated in the A direction of FIG. 4 in this state, the tip of the collet chuck 21 contracts in the inner diameter direction as shown in FIG. Since the collet chuck 21 including the cylindrical case 22 moves in the direction away from the toner storage container, the cap opens the ejection port 14d and the toner can be ejected. To do.

The structure of the toner replenishing device will be described in more detail with reference to FIGS. 4 and 5 and the like. Reference numeral 13 is a drive unit such as a motor for driving the toner replenishing device, which stores toner set on the case 18. A joint 13c that detachably engages with one end surface of the container 14, and a spring 13 that assists the engagement.
d, a motor 13e for rotating the toner storage container in the B direction
And a case portion having a built-in shaft, and is fixed to a case C around the photosensitive member or a rear side plate 31 provided in the main body of the image forming apparatus. Reference numeral 14 is a toner storage container, and the drive unit 1
3 on one end face in the axial direction facing 3
Is provided. The projecting portion 14b is a small cylindrical projection projectingly provided at the center of the circular container end surface. The projecting portion 14b fits into the recess 13b of the joint 13c, and the end surface of the toner storage container 14 is The two projections 14a have a rectangular shape and are arranged symmetrically with respect to the projection 14b.
The driving force for rotating the toner storage container 14 is transmitted by engaging with the side surfaces 13a of the two convex portions extending from the central concave portion 13b of c in the outer diameter direction. The member for holding the head of the toner storage container 14 (the other end in the axial direction = the right end in the drawing) is the bottle holding member 16. Bottle holding member 16,
The scraping member 17, the case 18 of the toner replenishing device, the collet chuck 21, the cylindrical case 22, the shaft member 23, the handle 26, the coil spring 28, and other parts are assembled to the receiving member 18A located at the end of the case 18. , The other end of the toner container 14 is supported. As will be described later, the bottle holding member 16 engages with the toner storage container 14 and integrally rotates.

Reference numeral 17 denotes a plate-shaped scraping member made of an elastic material such as mylar or rubber, and a plurality of plates integrally projecting from one end side in the axial direction of the hollow cylindrical bottle holding member 16. Hatching surfaces are attached to the outer surfaces of the ribs 16a (arranged at predetermined intervals in the circumferential direction) by double-sided tape or the like. The free end of the scraping member 17 is dimensioned and shaped so as to be in sliding contact with the inner peripheral surface of the receiving member 18A. In this embodiment, the rib 16a and the scraping member 17 are provided in four pieces, respectively, but this is merely an example, and any number may be provided. The inner wall surface of the toner storage container 14 is provided with a spiral ridge, and when the toner storage container is rotated, a spiral protrusion is formed so as to discharge the inner toner from the toner discharge port 14d. The direction, shape, and dimensions are set. A cap 15 that prevents the toner from being discharged is fitted into the toner discharge port 14d. As shown in FIGS. 6 and 7, the cap 15 has a base portion 15a that fits into the discharge port 14d and closes, and a clamped portion 1 that protrudes from the outer center portion of the base portion 15a and has a large diameter portion at the tip portion.
5b and so on.

As shown in FIG. 5, the rib 16b provided on the inner wall surface of the bottle holding member 16 is caught by the flat head portion 14c provided on the toner storage container 14, and the bottle holding member 16 and the toner storage container 14 are provided. Can rotate integrally.
Reference numeral 20 is a seal material fixed to the end surface of the cylindrical case 22, 21 is a collet chuck for picking and releasing the cap 15, and the collet chuck 21 is moved in the hollow cylindrical case 22 in the axial direction. Built in when possible,
It is integrated with the shaft member 23 by the screw 24. The shaft member 23 is also inserted into the cylindrical case 22. The cylindrical case 22 is supported by the inner wall 18Aa of the receiving member 18A so as to be able to advance and retract in the axial direction. The chuck claw 21a at the tip of the collet chuck 21 is elastically deformable in the inner and outer diameter directions, and does not clamp the clamped portion 15b of the cap 15 when the collet chuck 21 is expanded in the outer diameter direction as shown in FIG. When contracted as shown in FIG. 7, the clamped portion 15b is clamped. Reference numeral 28 is a coil spring that constantly presses parts such as the collet chuck 21, the cylindrical case 22, the shaft member 23, etc. toward the toner storage container 14 side. These components are the case (hereinafter referred to as the case of the toner replenishing device). A pedestal) 18 is held in a receiving member 18A so as to be axially movable.

Reference numeral 26 denotes a handle for opening and closing the cap 15, which is assembled to the end portion of the receiving member 18A and has shaft portions 26b projectingly provided on both outer side surfaces thereof.
By being fitted to the central shaft 32, it becomes possible to rotate in the vertical direction about the shaft portion 26b. Reference numeral 27 denotes a slide shaft which is inserted into a hole 23a provided at an end portion of the shaft member 23, and both end portions of the slide shaft 27 are assembled so as to project from the hole 23a, so that the projecting end portion has a handle 26. It comes into contact with the right end surface of the cam portion 26a provided on the. Therefore, by rotating the handle 26 in the direction A of FIG. 4, the cam portion 26a moves the slide shaft 27 to the outside, so that the series of components 21 to 23 slide in the direction away from the toner storage container 14. Can be made.

The toner replenishing device shown in FIG. 4 is held by guide plates attached to the body front side plate and the body rear side plate 31 not shown here. Receiving member 1 of pedestal 18
The two holes 18b formed in 8A are holes that engage with positioning pins provided in the front side plate (not shown), and 33 is a stopper for preventing the toner replenishing device from coming off, and a side plate. 30 is provided to prevent the toner replenishing device from falling off. As shown in FIG. 4, when the handle 26 is rotated in the A direction (downward), the cam portion 26a pulls the slide shaft 27 in the C direction in FIG. Then, the shaft 23 also starts moving in the C direction, and the collet chuck 21 moves into the cylindrical case.
The projection 22a provided on the inner peripheral surface of the cap 22 comes into contact with the projection 22, and accordingly, the chuck claw 21a at the tip of the collet chuck 21 is not closed until the non-clamping portion 1 of the cap 15 is closed.
Pick 5b. When the movement in the C direction further proceeds in this state, as shown in FIG. 7, the cap 15 of the toner storage container 14 is removed from the discharge port 14d by the collet chuck 21, and the toner inside the toner storage container 14 is removed. Cradle 18
Spills into. This state is the state in which setting of the toner storage container in the toner replenishing device is completed. Reference numeral 29 denotes a cover 29, which is fixed to the outside of the slit 19 provided in the receiving table 18 so that the toner introducing portion 12 and the slit 19 are air-tightly connected. An opening 29a communicating with the toner introducing portion 12 is formed in the lower part of the cover 29, and a winding motor 30 for gradually increasing the opening amount of the slit 19 and a winding motor 30 for gradually winding the opening. It has a sheet-like slit member 19a and the like which is gradually removed to widen the opening amount of the opening 29a.

Next, the operation of replenishing the toner will be described. For toner replenishment, the magnetic permeability sensor 34 shown in FIG. 2 detects the toner concentration in the developing tank of the developing device, and when it is detected that the toner concentration is below the reference concentration, the toner detection signal is received. The control unit operates the drive unit 13 shown in FIGS. 4 and 5 to rotate the joint 13c in the B direction. Then, the joint 13a causes the protrusion 14 on the bottom of the toner storage container 14 to
The toner storage container 14 starts to rotate by engaging with a. When the toner storage container 14 rotates, as shown in FIG.
The toner is discharged from the discharge port 14d and accumulated in the pedestal 18.
The arrow in FIG. 1 indicates this ejection direction. At the same time, the rotation of the toner storage container 14 is transmitted through the ribs (16b in FIG. 5) integrated with the bottle holding member 16, and the bottle holding member 1
The scraping member 17 fixed to 6 slides on the inner wall surface of the pedestal 18 to scrape the toner accumulated in the pedestal 18. The arrow in FIG. 1 indicates this scraping direction.
When the scraping member 17 passes through the slit 19 provided on the outer wall of the pedestal 18, the toner is pushed out from the slit 19 (FIG. 1, arrow). The pushed toner falls in the cover 29, and the lower opening (29) of the cover 29 is released.
The toner is replenished into the developing tank of the developing device from the toner introducing portion 12 of the developing device through a) (FIG. 1, arrow).

By the way, when there is a large amount of toner remaining in the toner storage container 14, the amount of toner discharged from the toner discharge port 14d is large, especially immediately after the container is replaced, so the amount of scraping by the scraping member 17 is also large. And, the toner becomes over-replenished. Therefore, in the present invention, the size of the slit provided in the slit member 19a is changed as shown in FIG. 5 so that the toner supply amount to the developing device is always constant. The slit member 19a having a tapered slit as shown in the drawing is gradually or gradually wound up by the winding motor 30 (the output gear 30a, the winding / sending bobbin 30b) so that the slit 18a of the slit 18a is formed. It is designed to change the aperture size. Immediately after the toner storage container 14 is replaced, the opening size of the slit is the smallest, and the opening size increases as the remaining toner decreases. This control is realized by the control unit driving the motor 30 as the toner consumption increases. The position of the slit member is reset when the toner container is replaced. In this control, a control unit (not shown) replaces (removes) the toner container.
It is realized by controlling the motor 30 when is detected. Here, a special mode for winding the slit member is used.
However, the toner storage container may be driven via a speed reduction mechanism.

[0016]

According to the invention of claim 1, an opening is provided for introducing the toner discharged from the toner discharge port of the toner storage container into the toner introducing portion, and the size of the opening is provided. Therefore, it is possible to provide a toner replenishing device having a simple structure capable of continuously replenishing a constant amount of toner to the developing portion while being low cost and compact. In the toner replenishing device according to the second aspect, since a plurality of toner scraping members are provided on the container holding means for holding the toner storage container and rotating integrally with the container, the toner is replenished little by little. However, it is possible to prevent uneven toner density and variations in the developing device, sufficiently stir and start up the toner, and prevent background stains and toner scattering.

According to the third aspect of the invention, the size of the opening for introducing the toner into the toner container is changed according to the remaining amount of toner in the toner container. It is possible to reduce the variation in the amount of toner discharged from the toner discharge port due to the amount of remaining amount, to keep the amount of toner supplied from the toner introducing portion constant, and to always provide a stable image density. In the toner replenishing device according to the fourth aspect, since the size of the opening is reset to the initial state when the toner storage container is replaced, the condition change by the replacement of the toner storage container is automatically performed and is always stable. It is possible to provide a system capable of obtaining the desired image density.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming unit including a developing device to which the present invention is applied.

FIG. 2 is a cross-sectional perspective view showing the overall configuration of the image forming unit in FIG.

FIG. 3 is an external view of the image forming unit in FIG.

FIG. 4 is an external view of the toner supply device of the present invention.

5 is an exploded perspective view of the toner supply device of FIG.

FIG. 6 is a sectional view showing the operation of the toner replenishing device of the present invention.

FIG. 7 is a sectional view showing the operation of the toner replenishing device of the present invention.

FIG. 8 is a configuration diagram of an image forming unit of a conventional image forming apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 photoconductor drum, 2 charger, 3 exposure part, 4 developing device, 5 transfer device, 6 cleaning device, 7 charge eliminating part, 13 drive part, 14 toner storage container, 14d discharge port, 15 cap, 16 bottle holding member, 17
Scraping member, 18 toner replenishing device case, 18A
Receiving member, 21 collet chuck, 22 cylindrical case,
23 shaft member, 26 handle, 28 coil spring, 2
8 etc. 14 toner storage container

Claims (4)

[Claims] 1. A tubular toner storage container having a toner discharge port formed at the center of one end side in the axial direction, and a state in which the toner can be introduced from this toner discharge port to a toner introducing portion of an image forming apparatus. In a toner replenishing device having container holding means for holding the toner storage container in a substantially horizontal direction, and rotation drive means held by the container holding means for rotating the toner storage container around its central axis. The container holding means is provided with an opening for introducing the toner discharged from the toner discharge port of the toner storage container into the toner introducing portion, and the size of the opening can be varied. A toner replenishing device characterized by the above. 2. The toner scraping member according to claim 1, wherein a plurality of toner scraping members are provided on a container holding means which holds the toner storage container and rotates integrally with the container.
Supply device. 3. The toner replenishing device according to claim 1, wherein the size of the opening for introducing the toner into the toner introducing portion changes according to the amount of toner in the toner storage container. The toner replenishing device according to claim 1. 4. The toner replenishing device according to claim 1, wherein the size of the opening is reset to an initial state when the toner storage container is replaced. .