JPH0546039Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an electrophotographic apparatus, and more particularly to a toner replenishing device for the electrophotographic apparatus.

"Prior art and its problems" In electrophotography, an electrostatic latent image is formed on a uniformly charged electrostatic photoreceptor drum such as a selenium drum. Colored toner (including black) with the same charging polarity as that of is attached and developed, and then this developed colored toner is transferred to the transferred object by transfer charging, and the image is used in copying machines, transfer facsimiles, etc. Widely used in processing equipment.

A developing device in this electrophotographic apparatus brings a developer made of a mixture of colored toner and carrier (magnetic powder) into contact with a photoreceptor drum, causes the toner to adhere to the electrostatic latent image, and collects the carrier. In order to perform this development well, it is necessary to keep the ratio of toner and carrier in the developer within a certain tolerance range, and in order to do so, it is necessary to detect an insufficient amount of toner (excessive carrier) in the developer. When this happens, it is necessary to quickly and reliably replenish the required amount of toner into the developer. To this end, toner replenishment devices with various structures have been proposed in the past, but the conventional products have had the problem of being complex in structure and high in cost.

"Objective of the Invention" An object of the present invention is to obtain a toner replenishing device that can replenish toner to a developer case with a simpler structure. Another object of the present invention is to provide a toner replenishing device that can drop and supply toner in a toner hopper into a developer case in a sufficiently agitated state.

"Summary of the invention" This invention is based on a developer case that holds a developer made of a mixture of toner and carrier, and a cylindrical toner hopper that stores toner for replenishment. A measuring shaft which normally closes this opening and has a measuring recess on a part of its circumference is rotatably provided, and a part of the measuring shaft is rotatably provided in the measuring recess. An elastic film having one end thereof as a protruding tongue protruding outward from the measuring shaft is provided along the fixed measuring shaft, and rotation of the measuring shaft causes the protruding tongue of the elastic film to engage and disengage from the opening end of the toner hopper. At the same time, it is characterized in that the toner in the toner hopper is supplied to the developer case.

"Embodiments of the invention" The invention will be described below based on the drawings. First, the concept of the electrophotographic apparatus to which the present invention is applied will be explained with reference to FIG. The photosensitive drum 11, which is rotationally driven in the direction of the arrow, is made of, for example, a selenium drum.
On its outer periphery are an electrostatic latent image forming means 12, a phenomenon device 13, a transfer charger (corona discharger) 14, a cleaning brush 15, and a photoreceptor charger 16.
are arranged along the rotation direction. A static eliminator is provided between the cleaning brush 15 and the charger 16 to make the surface potential of the photoreceptor drum 11 uniform.

The photoreceptor drum 11 is uniformly positively (or negatively) charged by being charged by the photoreceptor charger 16.
When the electrostatic latent image forming means 12 irradiates light having image information, charges are generated on the photoreceptor drum 11 in the direction of reducing the surface charge in the areas hit by the light. In other words, a potential difference is generated between the areas exposed to light and the areas not illuminated, and an electrostatic latent image is formed. Next, by the developing device 13, on the surface of the photoreceptor drum 11,
Positive (or negative) (same polarity as the charged polarity of the drum)
When a colored toner having a charge of 1 is supplied together with a carrier, the colored toner adheres to the electrostatic latent image and is developed.

The transfer charger 14 transfers the colored toner adhering to the photoreceptor drum 11 as a result of this development onto the PPC paper (transfer object) 18.
8 to a polarity different from that of the toner. That is, as a result of the PPC paper 18 being charged with a polarity different from that of the toner, the toner adhering to the latent image on the photosensitive drum 11 is transferred to the PPC paper 18 . The transferred colored toner is then transferred to a fixing device 19.
established by

The residual colored toner on the photosensitive drum 11 is removed by a cleaning brush 15. The photoreceptor charger 16 is a charger that returns the surface potential of the photoreceptor drum 11 to the initial positive (or negative) polarity.

The toner replenishing device of the present invention is attached to, for example, a developing device of an electrophotographic apparatus configured as described above. 1 to 4 show an embodiment of a developing device 20 equipped with a toner replenishing device according to the present invention. This developing device is characterized not only by a toner replenishing device but also by a developer conveying and agitating mechanism, which allows the developer to be uniformly supplied to the magnet roll and toner and carrier to be well agitated.

This developing device 20 has a developer case 21, and this developer case 21 includes a magnet roll 22, a front stirring roll 23, and a rear stirring roll 2.
4 are rotatably supported with their axes parallel to each other, and a cylindrical toner hopper 25 is fixed parallel to these. These are provided in such a manner that a pre-stirring roll 23 is located below the magnet roll 22, a post-stirring roll 24 is located below the toner hopper 25 and has the same height as the front stirring roll 23, and the magnet roll 22 is located below the toner hopper 25. A part of its peripheral surface is exposed from the developer case 21 and faces the photosensitive drum 11. The developer case 21 has a sealed structure except for the exposed portion of the photoreceptor drum 11.

Both the front agitation roll 23 and the rear agitation roll 24 are constructed of lead screws, and are interlocked by interlocking gears 23a and 24a that mesh with each other at a protrusion from the developer case 21, and rotate at the same speed in opposite directions. The magnet roll 22 rotates in synchronization with the front stirring roll 23 and the rear stirring roll 24. The arrows in FIG. 1 indicate these rotation directions. Due to the rotation of the front stirring roll 23 and the rear stirring roll 24, the developer flows in opposite directions below the magnet roll 22 and below the toner hopper 25. Forms a drug flow.

A magnet 26 whose polarity is shown in the figure is disposed and fixed inside the magnet roll 22, and the magnetic attraction force of the magnet 26 causes a developer made of a carrier made of magnetic powder and a mixture of toner to be attracted to the magnet roll 22. It is attached by suction to the surrounding surface. The height of the developer adhering to the magnet roll 22 is regulated by a doctor plate (ear cutting plate) 27, and the tip of the ear (developer) reaches the photoreceptor drum 11.
come into contact with.

Between the front stirring roll 23 and the rear stirring roll 24, there is a developer case 21 from the magnet roll 22.
A fall guide plate 28 for the developer falling therein is provided. The falling guide plate 28 has a lower end fixed to the bottom of the developer case 21 and an upper end extending to the side of the magnet roll 22. It consists of This inclined guide portion 28a guides almost all of the developer that falls past the top of the magnet roll 22 toward the front stirring roll 23 side.

Further, this falling guide plate 28 is connected to the front stirring roll 23.
A connecting flow path 32 that defines a front flow path 30 having a rear stirring roll 24 and a rear flow path 31 having a rear stirring roll 24, and a communication flow path 32 that communicates the starting end of the front flow path 30 with the terminal end of the rear flow path 31; A communication channel 33 is formed that communicates the terminal end of the channel 30 and the starting end of the rear channel 31. The flow area of the communication flow path 32 is
It is set wider than that of 3.

The developer feeding speed by the front stirring roll 23 and the rear stirring roll 24 is higher on the front stirring roll 23 (front passage 30) side than on the rear stirring roll 24 (rear passage 3) side.
1) It is set to be faster than the side, or to make both sides equal. In the case of the embodiment, this feeding speed can be controlled by setting the screw pitch of the front stirring roll 23 and the rear stirring roll 24.

The toner replenishing device, which is a feature of the present invention, is provided in the developer case 21 of the developing device 20 configured as described above, and includes a toner hopper 25.
has an opening 36 that opens into the developer case 21 at its lower part. The opening 36 is composed of a pair of opposing opening wall surfaces 36a hanging from the toner hopper 25, and a metering shaft 37 is disposed between the pair of opening wall surfaces 36a with its peripheral surface in close contact. has been done. Therefore, it is desirable that the opening wall surface 36a be made of a leaf spring-like material that has elasticity toward the measuring shaft 37 side. Appropriate sealing means are provided between both ends of the opening wall surface 36a in the direction perpendicular to the paper plane of FIG. 1 and both ends of the measuring shaft 37.

A measuring recess 38 consisting of a V-groove is formed on the circumferential surface of the measuring shaft 37, and an elastic film 39 is further provided along the measuring recess 38.
The elastic film 39 is made of an insulating and elastic (restorable) film such as polyimide film, and one end thereof is formed into the measuring recess 3.
8, and the other end constitutes a protruding tongue piece 39a that protrudes outward from the measuring shaft 37. The protruding tongue piece 39a projects outward from the rear slope of the pair of slopes of the metering recess 38 in the direction of rotation of the metering shaft 37. This protruding tongue piece 3
The number 9a may be provided over the entire length of the measurement recess 38 in the direction perpendicular to the plane of the paper, or a plurality of number 9a may be provided at appropriate intervals.

When the measuring recess 38 is directed into the toner hopper 25, it receives the supply of toner that falls within the toner hopper 25, and when it is directed downward, it causes the supplied toner to fall into the developer case 21. The position of this measuring shaft 37 is controlled so that it always stops with its measuring recess 38 facing inside the toner hopper 25, and when rotating,
It rotates while bringing its peripheral surface into contact with the opening wall surface 36a. At this time, the protruding tongue piece 39a is bent backward in the rotational direction of the metering shaft 37 by the left opening wall surface 36a in FIGS. Engagement (contact) with wall surface 36a
Solve. By this disengagement, the protruding tongue piece 39a returns to the front due to its elastic restoring force. At this time, the entire elastic film 39 is repelled and receives a shock, and the toner (if any) that was about to remain attached to the elastic film 39 falls into the developer case 21. Therefore, toner equal to the capacity of the metering recess 38 is supplied into the developer case 21 each time the metering shaft 37 rotates once.

A stirring shaft 40 is further rotatably disposed within the toner hopper 25 at its shaft portion. A stirring blade 41 is fixed to the stirring shaft 40, and when the stirring shaft 40 rotates, the stirring blade 41 stirs the toner in the toner hopper 25 and reliably supplies it into the metering recess 38. This stirring shaft 40 is driven by a drive motor 42
and an electromagnetic clutch device 43,
The stirring shaft 40 and the measuring shaft 37 are interlocked to rotate at a predetermined rotation speed ratio.

A toner sensor 44 is arranged above the magnet roll 22 to face it. This toner sensor 44 measures the component ratio of the carrier made of magnetic powder and the toner by measuring the magnetic permeability of the developer attracted and adhered to the magnet roll 22, and indirectly measures the relative toner toner ratio. Detects a shortage of carriers (an excess of carriers). This toner sensor 44
is connected to a clutch control device 45 that controls an electromagnetic clutch device 43, and is connected to a toner sensor 44.
When a shortage of toner is detected, the stirring shaft 40
And the measuring shaft 37 rotates a predetermined number of times. The driving force for the magnet roll 22, front stirring roll 23, and rear stirring roll 24 is obtained from a drive motor 42, but the drive system thereof is not shown.

The developing device 20 having the above configuration includes a magnet roll 22, a front stirring roll 23, and a rear stirring roll 2.
4, as shown by the arrows in FIGS. 2 and 3, the developer flow circulates between the front flow path 30 and the rear flow path 31 by the front stirring roll 23 and the rear stirring roll 24. configured. In the front flow path 30, a portion of the developer adheres to the circumferential surface of the magnet roll 22, and the developer whose adhesion height is regulated by the doctor plate 27 is applied to the surface of the photoreceptor drum 11. Upon contact, only the toner adheres to the electrostatic latent image formed on the drum. The toner and carrier that have not adhered fall to the front flow path 30 (front stirring roll 23) side by the falling guide plate 28, and the amount of developer on the front flow path 30 side is ensured.

Further, since the communication channel 33 is narrower than the communication channel 32, the amount of developer flowing from the front channel 30 into the rear channel 31 is reduced from the rear channel 31 to the front channel 32.
It is less compared to that flowing into the interior. That is, a portion of the developer flow tends to stay on the front flow path 30 side, and the developer can be reliably supplied to the magnet roll 22.

Furthermore, since the feeding speed of the front stirring roll 23 is set to be equal to or slower than the feeding speed of the rear stirring roll 24, it is possible to secure the developer in the front flow path 30 and obtain a good stirring effect. Can be done.

When the amount of toner in the developer decreases to a predetermined amount or less as a result of continued operation, the toner sensor 44 detects this and stirs the toner via the clutch control device 45, electromagnetic clutch device 43, and drive motor 42. The shaft 40 and the measuring shaft 37 are rotated a predetermined number of times. Then, the toner held in the metering recess 38 falls into the developer case 21 a number of times corresponding to the number of rotations of the metering shaft 37 and is replenished.

That is, when the measuring shaft 37 rotates, the measuring recess 3
8 begins to face inside the developer case 21, the protruding tongue piece 39a of the elastic film 39 is bent rearward in the rotational direction of the metering shaft 37 by the opening wall surface 36a of the opening 36. Then, the metering recess 38 turns completely downward and further rotates, and when the engagement (contact) with the opening wall surface 36a is released, it returns to the front as if flipped. This return to the front applies a slight shock or vibration to the entire elastic film 39, thereby causing the toner that would have remained attached to the elastic film 39 to fall into the developer case 21. The fallen toner is at least stirred in the rear flow path 31 and then transferred to the front flow path 30.
Therefore, the developer attracted and adhered to the magnet roll 22 will not be stirred insufficiently.

Note that it takes a certain amount of time for the replenished toner to reach the portion on the magnet roll 22 facing the toner sensor 44. Therefore, it is desirable to provide means for ignoring the toner shortage signal from the toner sensor 44 for a predetermined period of time after the electromagnetic clutch 43 is turned on by the clutch control device 45.

Further, the means for replenishing toner to the toner hopper 25 is not a matter of concern to the present invention, but for example,
By inserting and removing the toner hopper 25 from the axial direction between the holding member 36b having the opening wall surface 36a and the arcuate projecting portion 21a at the upper part of the developer case 21, the toner hopper 25 itself can be replaced. Then, you can replenish toner. In the above description, the present invention is applied to a single-color electrophotographic device, but in a color copying device having a plurality of developing devices of different colors, the present invention is applied to the toner replenishing device of each color developing device. It is clear that it can be done.

"Effects of the Invention" As described above, according to the toner replenishing device for an electrophotographic apparatus of the present invention, by rotating the measuring shaft provided in the opening of the toner hopper, the amount of toner determined by the measuring recess provided in the measuring shaft is delivered. can be supplied into the developer case. An elastic film is attached to the measuring recess, and the protruding piece of the elastic film engages and disengages from the opening end as the measuring shaft rotates, so that the toner can be reliably discharged from the measuring recess. Therefore, although it has a simple mechanism, it can replenish toner quickly, reliably, and in an accurate amount, reducing the cost of this type of toner replenishing device.
and miniaturization can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the developing device of the electrophotographic apparatus of the present invention, FIGS. 2A and B are enlarged views of the measuring recess of the measuring shaft and the elastic film portion, and FIG. 3 is the same as that of FIG. FIG. 4 is a sectional view taken along the line - in FIG. 3, and FIG. 5 is a conceptual diagram of an electrophotographic apparatus to which the present invention is applied. 11...Photosensitive drum, 12...Electrostatic latent image forming means, 13...Developing device, 14...Transfer charger, 15...Cleaning brush, 16...Charger, 18...PPC paper (covered) Transfer material), 20... Developing device, 21... Developer case, 22... Magnet roll, 23... Front stirring roll, 24... Post stirring roll, 25... Toner hopper, 26... Magnet, 27... …Doctor plate (ear cutting board),
28...Fall guide plate, 30...Front side channel, 31...
... Rear channel, 32, 33... Connection channel, 36...
Opening, 36a...opening wall surface, 37...measuring axis,
38...Measuring recess, 39...Elastic film, 39
a... Protruding tongue piece, 40... Stirring shaft, 41... Stirring blade, 42... Drive motor, 43... Electromagnetic clutch device, 44... Toner sensor, 45... Clutch control device.

Claims (1)

[Claims for Utility Model Registration] (1) An electrostatic latent image is formed on a charged electrostatic photoreceptor drum, and a colored toner having the same polarity as the charging polarity of the electrostatic photoreceptor drum is added to the electrostatic latent image. In an electrophotographic device that deposits a toner and develops it, transfers it to an object, and then develops it, a cylindrical toner hopper that stores replenishment toner is placed in a developer case that holds a developer made of a mixture of toner and carrier. An opening to the developer case is provided at the bottom of the toner hopper, and a metering shaft that normally closes the opening and has a metering recess on a part of its circumference is rotatably provided. At the same time, an elastic film is provided along this measuring recess, a part of which is fixed in the measuring recess, and one end of which is a protruding tongue protruding outward from the measuring shaft, and as the measuring shaft rotates, the elastic film A toner replenishing device for an electrophotographic apparatus, characterized in that the toner in the toner hopper is supplied to the developer case while the protruding tongue piece is engaged with and disengaged from the end of the opening. (2) In claim 1 of the utility model registration claim, the toner hopper is further provided with a rotatable stirring shaft on its shaft portion, and the stirring shaft is provided with stirring blades. Supply equipment. (3) In claim 1 or 2 of the utility model registration claim, the developer case includes a magnet that is partially exposed from the case to the photosensitive drum side and that rotates with developer attached to the outer periphery. a pre-stirring roll located below the magnet roll, which causes the developer in the developer case to flow under the magnet roll; and a pre-stirring roll located behind the pre-stirring roll. A post-stirring roll that creates a developer flow in the opposite direction to the developer flow caused by the magnetic roll, and a falling guide that is installed between the front and rear stirring rolls and mainly guides the developer falling from the magnet roll toward the front-stirring roll. A toner replenishing device for an electrophotographic device, which is provided with a plate. (4) In claim 3 of the utility model registration, a toner sensor is provided in opposition to the magnet roll to detect the ratio of toner to carrier in the developer, and this toner sensor detects a shortage of toner. An electrophotographic toner replenishing device in which the measuring shaft and stirring shaft rotate a predetermined number of times.