JPH04107488A - Remaining toner detection device of electrophotographic printer - Google Patents

Abstract

PURPOSE:To prevent the print quality from deteriorating by providing a means which vibrates an end part of a toner sensor shaft, and detects flexural vibration and detecting the amount of toner. CONSTITUTION:A toner tank 19 s set and toner 19a which is fallen in a developing unit falls on a slanting surface 21a atop a toner sensor blade 21. Then when a switch is turned on, a main motor is driven and all of a roller, a shaft, and a photosensitive drum begin to rotate. At this time, the toner sensor shaft 20 is to begin to vibrate as shown by an arrow through the operation of the operation of a coil and a magnet 33 simultaneously with the ON operation of the switch, but the toner sensor blade 21 fitted to the toner sensor shaft 20 is impeded by the toner 19a fallen from the toner tank 19 from moving, so no flexural vibration is caused. Then a toner FULL state is detected. Consequently, the print quality is prevented from deteriorating.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a remaining toner amount detection device in an electrophotographic printer.

(Prior Art) Conventionally, an electrophotographic printer irradiates a charged photosensitive drum with a light source to form an electrostatic latent image on its surface, and develops it by attaching toner to the electrostatic latent image. After that, the toner image is transferred to a recording medium.

In the developing device of the electrophotographic printer configured as described above, the toner in the toner tank is supplied to the photosensitive drum and is deposited on the surface of the photosensitive drum, so that the amount of toner decreases each time printing is performed. Therefore, it is necessary to periodically replenish the toner tank with toner.

Figure 4 is a cross-sectional view of the developing device of a conventional electrophotographic printer.
FIG. 5 is a perspective sectional view of a developing device of a conventional electrophotographic printer, and FIG. 6 is an exploded perspective view of the developing device of a conventional electrophotographic printer.

In the figure, the toner tank 1 is formed by stacking two pipes, the outer pipe is attached to the developing device so as not to rotate, and the inner pipe is rotated by levers (not shown) provided at both ends of the toner tank 1. be able to.

The toner tank 1 is filled with toner 1a and is detachably attached to the developing device.

That is, when all of the toner 1a is used, the toner tank 1 is removed from the developing device and replaced with a new toner tank.

A stirring shaft 2 is installed below the toner tank 1. The stirring shaft 2 is formed by winding a linear material in a coil shape onto the shaft, and is driven and rotated by a main motor (not shown). A sponge roller 3 is provided diagonally below the stirring shaft 2. The sponge roller 3 adheres the fallen toner 1a and conveys it to the developing roller 4. Therefore, the circumferential surface of the sponge roller 3 is pressed against the circumferential surface of the developing roller 40, and the toner 1a that has landed on the sponge roller 3 is transferred to the circumferential surface of the developing roller 4.

Further, a developing blade 5 is disposed in pressure contact with the circumferential surface of the developing roller 4, and regulates the toner 1a adhering to the circumferential surface of the developing roller 4 to form a uniform layer.

The circumferential surface of the developing roller 4 and the circumferential surface of the photosensitive drum 6 are in contact with each other, and above the photosensitive drum 6 is a print head 7.
However, a transfer device 8 is provided below.

Furthermore, the edge portion of the cleaning blade 9 is in pressure contact with the circumferential surface of the photosensitive drum 6. This cleaning blade '9 is attached to the opening side of the toner collecting section 10, is made of an elastic material such as urethane rubber, and scrapes off residual toner adhering to the circumferential surface of the photosensitive drum 6.

The scraped off residual toner is collected in the toner collecting section 10. An integrally molded blade shaft 11 for conveying toner having a coil spring shape is disposed inside the toner collecting unit 1o, and the scraped residual toner is transferred to an integrally molded blade shaft in a toner return pipe (not shown). It is sent to the stirring shaft 2 through the stirring shaft 2.

A sensor shaft 13 with a blade 12 removed is disposed above the developing roller 4 and the sponge roller 3, and a coupling 15 having a magnet 14 is attached to the tip thereof, and the sensor shaft 13 rotates in the direction of the arrow. I am made to do so. In addition, a sensor sensor 16 is rotatably disposed at a position facing the compulsory ring 15 and has a magnet with a polarity opposite to that of the magnet eye 4. The sensor sensor 16 rotates in conjunction with the rotation of the sensor shaft 13, The upper optical sensor 18 is turned on and off.

In addition, 51 is a toner tank in which the above-mentioned toner tank 1 is set, 52 is an ET' cartridge, 53a, 53b
are side frames arranged at both ends of the EP cartridge 52.

Next, the operation of the developing device having the above configuration will be explained.

When the main motor (not shown) is driven, all the rollers and shafts start rotating. When the sponge roller 3 rotates, the toner 1a adheres to its circumferential surface and is conveyed in the direction of the arrow, and transferred to the circumferential surface of the developing roller 4. Then, the developing roller 4 transfers the toner 1a attached to the surface to the photosensitive drum 6.

The surface of the photosensitive drum 6 is uniformly charged by a charger (not shown), but when it is irradiated with light from the print head 7, the amount of charge on the surface changes, forming an electrostatic latent image. Then, the supplied toner 1a adheres to this electrostatic latent image to form a toner image.

Therefore, when the recording medium passes between the photosensitive drum 6 and the transfer device 8, the toner 1a on the circumferential surface of the photosensitive drum 6 is transferred onto the surface of the recording medium by the transfer device 8, and then thermally fixed by the fixing device.

Incidentally, the residual toner on the surface of the photosensitive drum 6 is scraped off by a cleaning blade 9, and is sent to a toner return pipe (not shown) via an integrally molded blade shirt 1, and is sent to an integrally molded blade shaft inside the toner return pipe. It is sent to the developing device via the stirring shaft 2, and is again supplied to the circumferential surface of the sponge 1:]-ra 3 via the stirring shaft 2.

Next, a method for detecting the amount of toner in the developing device will be explained.

The toner 1a conveyed to the circumferential surface of the developing roller 4 by the sponge roller 3 is made uniform by the developing blade 5, and the toner 1a scraped off from the circumferential surface of the developing roller 4 at this time moves the blade 12 in the direction of the arrow. Rotate the push sensor shaft 13. As a result, the sensor lever 16 facing the coupling 15 is rotated, and the optical sensor 18
interrupts conduction. As a result, the inside of the developing device is filled with toner 1.
It is detected that a is full. After that, toner 1a
When the force decreases, the blade 12 is no longer pressed, and the sensor shaft 13 is rotated in the opposite direction by a torsion coil spring (not shown). At this time, the optical sensor 18 becomes conductive and the toner 1
It is detected that a has decreased.

(Problem to be Solved by the Invention) However, in the toner remaining amount detection device included in the electrophotographic printer having the above configuration, when a sufficient amount of toner is stored inside the developing device, the developing blade 5 and the blade 12
The pressure between the developing blade 5 and the developing roller 4 increases, and the developing blade 5 is separated from the developing roller 4, and the toner layer on the circumferential surface of the image roller 4 becomes thicker, causing fog to appear on the print and deteriorating the print quality.

The present invention solves the problem of the remaining toner amount detection device in the conventional electrophotographic printer described above, and even if the pressure inside the developing device increases by 1, the developing blade is separated from the developing roller, resulting in a decrease in print quality. It is an object of the present invention to provide a toner remaining amount detection device for an electrophotographic printer that never fails.

(Means for Solving the Problems) To this end, the present invention provides a photosensitive drum, a means for charging the surface of the photosensitive drum, and a means provided opposite to the photosensitive drum for charging the surface of the photosensitive drum.
A means for exposing a charged photosensitive drum to form an electrostatic latent image, a developing device provided opposite to the photosensitive drum for forming a toner image corresponding to the electrostatic latent image, and a means for transferring the toner image to a recording medium. In a toner remaining amount detection device for an electrophotographic printer having a means for transferring and fixing, a toner tank is removably disposed above the developing device, and a toner tank is connected to the developing device through an opening formed at the bottom of the toner tank. The toner is supplied by dropping into the container.

Inside the developing device below the opening of the toner tank,
A toner sensor vane supported by a toner sensor shaft is disposed.

A means for generating flexural vibration is provided at an end of the toner sensor shaft, and a means for detecting the flexural vibration is provided.

(Function) According to the present invention, the toner tank is removably disposed above the developing device as described above, and the toner is supplied falling into the developing device through the opening formed at the bottom of the toner tank. A toner sensor blade supported by a toner sensor shaft is disposed inside the developing device below the opening of the toner tank, and a flexible blade is provided at the end of the toner sensor shaft. A means for generating vibration is provided, and the amount of toner is detected by detecting the deflection vibration.

That is, when there is sufficient toner in the developing device, the flexural vibration of the toner sensor blade is hindered by the toner, but when the amount of toner is low, the flexural vibration is not hindered.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a remaining toner amount detection device in an electrophotographic printer showing an embodiment of the present invention, and FIG. 2 is an arrangement of toner sensor blades used in the remaining toner amount detection device in an electrophotographic printer of the present invention. It is a diagram.

In FIG. 1, the toner tank 19 is formed by stacking two pipes, and is filled with toner 19a.

An opening is formed in each of the inner pipe and the outer pipe, and the openings do not coincide with each other before being mounted on the developing device, so that the toner 19a does not leak.

After installing the 1-Nakunk 19 in the developing device, when only the inner pipe is rotated by a lever (not shown) while the outer pipe is fixed, the openings of the inner and outer pipes match and the toner 19a is supplied into the developing device. be done. After all the toner 19a is consumed, the inner pipe is rotated again to close the opening, and in this state, it is removed from the developing device.
You can replace it with a new toner tank.

A stirring shaft 22 is installed below the toner tank 19. The stirring shaft 22 is formed by winding a linear material part in a coil shape around the shaft.
A main motor (not shown) drives and rotates this.

A sponge roller 2 is disposed diagonally below the stirring shaft 22.
3 are arranged. The sponge roller 23 is in contact with the peripheral surface of a developing roller 24 , and the fallen toner 19 a is adhered thereto and conveyed to the developing roller 24 .

Further, a developing blade 25 is disposed around the developing roller 24 in pressure contact with the developing roller 24 to form a uniform layer of the toner 19a adhering to the circumferential surface of the developing roller 24.

The circumferential surface of the developing roller 24 and the circumferential surface of the photosensitive drum 26 are in contact with each other, and a print head 27 is disposed above the photosensitive drum 26 and a transfer device 28 is disposed below.

Further, an edge portion of a cleaning blade 29 made of an elastic material such as urethane rubber is in pressure contact with the circumferential surface of the photosensitive drum 26, and scrapes off residual toner adhering to the circumferential surface of the photosensitive drum 26.

Therefore, the cleaning blade 29 is attached to the opening side of the toner collecting section 30 LJ.

The scraped off residual toner is collected in the toner collecting section 30. Inside the toner collection section 3o,
An integrally molded blade shaft 31 for conveying toner having a coil spring shape is provided, and the scraped residual toner is sent to a toner return pipe (not shown). The toner return pipe supplies residual toner to the agitation shaft 22 via an integrally formed vane shaft disposed therein.

Further, above the developing roller 24 and the sponge roller 23, a toner sensor shaft 20 to which a toner sensor blade 21 is attached is arranged so as to be able to bend and vibrate in the direction of the arrow in FIG. A coupling 32 having a magnet 33 and a yoke plate 34 is attached to the tip. A coil block 35 having a coil set therein is disposed on the substrate of the electrophotographic printer at a position facing the magnet 33 when the developing device is set in the electrophotographic printer. The coils in the coil block 35 are connected by a coil bobbin 36.

Next, the operation of the developing device having the above configuration will be explained.

Before turning on the switch, set the toner tank 19,
The toner 19a is dropped into the developing device. The fallen toner 19a falls onto the slope 21a at the tip of the toner sensor blade 21. Thereafter, when the switch is turned on, a main motor (not shown) is driven, and all the rollers, shafts, and photosensitive drums start rotating.

At this time, at the same time as the switch is turned on, the toner sensor shaft 20 also begins to bend and vibrate in the direction of the arrow due to the action of the coil and magnet 33, but the toner sensor blade 2 attached to the toner sensor shaft 20
1 is prevented from moving by the toner 19a that has fallen from the toner tank 19, so no flexural vibration occurs. This detects the toner full state.

Fig. 3 is a diagram showing the principle of generation of flexural vibration, Fig. 3 (8) is a coil arrangement diagram, and Fig. 3 (B) is a diagram of the state in which flexural vibration occurs.

In the figure, a coil block 35 is arranged at a position facing the magnet 33, and the coil block 35 includes two coils (not shown) arranged in the vertical direction and two coils 36 and 37 arranged in the horizontal direction. have. The longitudinal coils exhibit the same polarity and the transverse coils 36.
37 is designed to periodically show reverse polarity.

On the other hand, as shown in FIG. 3(B), the magnet 33 attached to the tip of the toner sensor shaft 20 has an N pole and an S pole. Therefore, the above coil 36.37
By alternately applying opposite polarities to the toner sensor shaft 20, deflection vibration can be generated.

Then, when the sponge roller 23 rotates, the toner 19
a adheres to the circumferential surface and is transferred to the circumferential surface of the developing roller 24. The developing roller 24 has toner 19a attached to its surface.
is transferred to the photosensitive drum 26. The surface of the photosensitive drum 26 is uniformly charged by a charger (not shown), but when it is irradiated with light from the print head 27, the amount of charge on the surface changes, forming an electrostatic latent image. Then, the supplied toner 19a adheres to this electrostatic latent image to form a toner image.

Therefore, when the recording medium passes between the photosensitive drum 26 and the transfer device 28, the toner 19 on the circumferential surface of the photosensitive drum 26
a is transferred onto the surface of the recording medium by the transfer device 28 and thermally fixed.

By the way, photosensitive dragon! , 25 is scraped off by a cleaning blade 29 and supplied to a toner return pipe (not shown) via an integrally molded blade shaft 31. Then, the toner is sent to the developing device via the integrally molded blade shaft 3 housed in the toner return pipe, and is sent to the developing device via the stirring shaft 22 and again to the sponge roller 23.
is supplied to the circumferential surface of the

Next, a method for detecting the amount of toner in the developing device will be explained.

While the printer is operating, toner 19a that has fallen from the toner tank 19, residual toner that has been conveyed by the agitation shaft 22, and toner on the circumferential surface of the developing roller 24 that has been scraped off by the developing blade 25 is collected by the toner sensor blade 2I. ball,
Toner sensor shaft 20 and toner sensor blade PA2]
This prevents the vibration of the toner and indicates the toner full state.

Then, when the toner 19a inside the developing device is consumed, the toner 19a that collects on the toner sensor blade 21 decreases, and the toner sensor shaft 20 and the toner sensor blade 21 decrease.
starts to vibrate and detects that the amount of toner 19a has decreased.

Thereby, the toner Lo- state can be detected.

(Effects of the Invention) As described in detail above, according to the present invention, the toner tank is removably disposed above the developing device, and the toner tank is inserted into the developing device through the opening formed in the lower part of the toner tank. A toner sensor blade supported by a toner shaft is disposed inside the developing device below the opening of the toner tank, and an end of the toner sensor shaft is disposed inside the developing device. The unit is provided with a means for generating a deflection vibration, and the amount of toner is detected by detecting the deflection vibration, so that the pressure of the toner between the toner sensor blade and the image brake 1 increases. This prevents the developing blade from being separated from the developing roller more than necessary.

Therefore, it is possible to prevent the print quality from deteriorating.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a remaining toner amount detection device in an electrophotographic printer showing an embodiment of the present invention, and FIG. 2 is an arrangement of toner sensor blades used in the remaining toner amount detection device in an electrophotographic printer of the present invention. Figure 3 is a diagram of the principle of generation of flexural vibrations, Figure 3 (A) is a coil arrangement diagram, Figure 3 (8) is a diagram of the state of occurrence of flexural vibrations, and Figure 4 is a conventional electrophotographic printer developing image. FIG. 5 is a perspective sectional view of a developing device of a conventional electrophotographic printer, and FIG. 6 is an exploded perspective view of the developing device of a conventional electrophotographic printer. 19... Toner tank, 19a... Toner, 20.
... Toner sensor shaft, 21 ... Toner sensor blade, 22 ... Stirring shaft, 23 ... Sponge roller, 24 ... Developing roller, 25 ... Developing blade,
26... Photosensitive drum, 27... Print head, 28...
...Transfer device, 29...Cleaning plate', 30
...Toner collection section, 31...Integrated blade shaft. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of Claims] A photosensitive drum, a means provided opposite to the photosensitive drum for charging the surface of the photosensitive drum, a means for exposing the charged photosensitive drum to form an electrostatic latent image, and a photosensitive drum. In a toner remaining amount detection device for an electrophotographic printer, the toner remaining amount detection device is provided in an electrophotographic printer and has a developing device that is provided opposite to the electrostatic latent image and forms a toner image corresponding to an electrostatic latent image, and a means for transferring and fixing the toner image onto a recording medium. ) a toner tank detachably disposed above the developing device and supplying toner falling into the developing device through an opening; (b) a toner sensor disposed below the opening of the toner tank; (c) a toner sensor shaft that supports the toner sensor blade; (d) means disposed at an end of the toner sensor shaft to generate flexural vibration; and (e) flexure of the toner sensor shaft. 1. A toner remaining amount detection device for an electrophotographic printer, comprising means for detecting vibration.