JPH0511593A - Developing device for image forming device - Google Patents

Abstract

PURPOSE:To prevent the generation of an abnormal sound on a pressing part to the napping of toner, on a developing roller rotating a cylindrical sleeve on the circumference of a magnetic member, and pressing the toner attracted to the circumference of the sleeve by the magnetic member, by a blade member, to from a thin layer. CONSTITUTION:The developing roller 25 disposed on a location corresponding to the photosensitive drum of a developing device, rotates the sleeve 27 composed of a nonmagnetic substance, on the circumference of the magnetic member 26 on which plural magnetic poles are disposed, to form the napping Th of the toner by the magnetic force of the magnetic member. An action to press the napping Th of the toner by the blade member 20 is applied, and the thickness of the toner is regulated, but a width (a) for forming the napping of the toner by the magnetic force of the magnetic member is set at about 35 deg.. Then, a width for rubbing the napping of the toner by the blade member is set narrow, so that the abnormal sound generated by the rubbing against the napping of the toner can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system such as an electronic copying machine or a laser printer, which is a thin layer regulating portion of toner formed on a developing roller of a developing device. Regarding means for controlling the range of toner spikes,
In particular, the present invention relates to a device for preventing the generation of abnormal noise by using a means for regulating the width of the toner spike range in the section pressed by the blade member.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic system such as an electronic copying machine and a laser printer, a thin film layer of toner is formed on the surface of a developing roller of a developing device and a photosensitive drum or the like is formed. A means for forming a toner image by exposing the toner to the developing portion of the image carrier and causing toner to fly to the electrostatic latent image on the photosensitive drum is used. As the developing device, for example, a device as disclosed in JP-A-63-220285 is used. In the developing device, a toner cartridge is attached to the main body frame, the toner contained in the cartridge is sent toward the developing roller, and the toner is transferred to the surface of the sleeve of the developing roller. A means for attaching the toner by the magnetic force of the magnet member and exposing the toner toward the developing area is used.

In the developing device shown in the above-mentioned conventional example, a developing roller having a structure as shown in FIG. 6 is used, and a blade member 30 made of rubber or the like is used for the developing roller 25. A pressing plate 32 is arranged to regulate the layer thickness of the toner T attached to the surface of the sleeve 27 of the developing roller 25. The developing roller 25 is provided with a magnet member 26 therein, and a cylindrical sleeve 27 made of a non-magnetic material is provided so as to rotate in a direction of an arrow X, and toner is attracted by the magnetic force of the magnet member. The toner is adsorbed on the surface, and the toner layer is pressed by a blade member to form a thin layer having a constant thickness, and the thin layer is exposed in the developing area of the photosensitive drum.

As shown in the figure, the blade member 30 has a sleeve 27 in which N and S magnetic poles of a plurality of magnets are alternately arranged.
And a mechanism for exposing the toner T to the developing area while the toner is attracted to the surface of the sleeve by the magnetic force of the magnet member. As shown in FIG. 7, the toner adhering to the surface of the sleeve 27 is formed with toner spikes Th, and the spikes Th of the toner are pressed by the plate member 31 of the blade member 30, and the thickness of the toner is increased. By controlling the height, the height of the spikes of the toner Th in the developing unit can be controlled.

[0005]

In the conventional developing device described above, the width of the pressing plate 32 of the blade member 30 is particularly strict at the portion where a thin layer of the toner spikes Th is formed on the surface of the developing roller. No need to set. Therefore, since it is only necessary to form a thin layer of toner on the surface of the sleeve 27 of the developing roller 25, the width of the plate and the pressing force of the plate spring member should be suitable for forming the thin layer. It is set. However, in the area where the pressing plate is pressed against the surface of the sleeve, as shown in FIG. 7, the pressing plate pressed against the surface of the sleeve forms a thin layer of toner while pushing down the spikes of toner. The action takes place. Then, when forming the thin layer, there is a problem that abnormal noise is generated at the portion pressed by the blade member.

That is, in the example shown in FIG.
At the upstream portion A1 of the surface of the sleeve 27 that is pressed by the pressing plate 32 of the blade member, the toner spikes are relatively high. And
At the portion A2 where the pressing plate 32 strongly presses the sleeve 27 to regulate the toner layer thickness, a thin layer is formed in a state where the spikes Th of the toner are pulled down, and the downstream portion A2 of the pressing portion A2.
In region 3, the thin layer of toner again forms ears by the magnetic force of the magnet. A thin layer forming part for the developing roller, a pressing part by a blade member,
Although an abnormal noise is generated due to the effect of tilting the spikes of the toner, in the conventional developing device, there is no particular problem because it is mixed with noise generated from other devices.

However, in recent years, each operating member such as a copying machine,
In the recent environment in which the noise generated from the rotating member is regarded as a problem, abnormal noise in the thin layer forming portion, which has not been a problem in the past, is becoming a problem. As described above, the abnormal noise generated when the blade member is pressed toward the surface of the developing roller to form the thin layer of toner is caused by the rise of toner in the portion where the pressing plate presses the sleeve. It is related to the width (the length of the sleeve in the arc direction ... hereinafter called the width). Then, it has been found that when the developing roller is pressed by the blade member to form a thin layer, a large noise is generated when the width of the spikes of the toner is wide.
However, regulating the width of the toner spikes in the thin layer forming portion also affects the amount of toner adhering to the surface of the sleeve of the developing roller, and therefore effective measures can be taken. There was a problem of not having.

[0008]

SUMMARY OF THE INVENTION The present invention solves the problem of abnormal noise generated in the toner thin layer forming portion in the conventional developing device as described above. It is an object of the present invention to provide a means for reducing the generation of abnormal noise by regulating the width of the rising of the toner formed by the above.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a developing roller is arranged corresponding to a photosensitive drum, and a sleeve is arranged around a magnet member provided on the developing roller. A developing device configured to adsorb toner on the surface of the toner with a magnet member, press the toner with a blade member to regulate the layer thickness of the toner, and expose the toner toward the developing area of the photosensitive drum. In the developing device of the present invention, a means for regulating the width of the toner attracted by the magnet member is provided at the portion where the layer thickness is regulated by the blade member for the toner adhered to the surface of the developing roller. Further, in the present invention, the width of the toner spike portion can be regulated by setting the width of the magnet member corresponding to the blade member to be narrow at the portion where the blade member regulates the toner layer thickness.
Further, in the present invention, in the magnet member provided in the portion corresponding to the blade member, the action width of 80% of the magnetic force of the magnet member is set so that the angle becomes approximately 35 ° with respect to the rotation center of the sleeve. Can be set.

As described above, in the thin layer forming portion for the developing roller, in order to control the width of toner adhered to the sleeve, a means for regulating the width of the toner attracted to the surface of the sleeve by the magnet member is provided. By providing it, in the developing device of the present invention, the width of the portion pressed by the blade member can be easily set. Further, when the width of the magnetic pole of the magnet member with respect to the surface of the sleeve is set to be narrow, it is not necessary to change the mechanism of the magnet member of the developing roller to a large width. It is possible to configure a device that is substantially similar to the La. Then, by controlling the generation of abnormal noise in the layer thickness regulating section, it becomes possible to reduce noise and the like generated from the copying machine.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device for an image forming apparatus of the present invention will be described with reference to the illustrated example. The developing device 20 of the present invention shown in FIG. 1 is provided with a developing roller 25 corresponding to the developing area of the photosensitive drum 5 provided as an image carrier. The developing roller 25 is provided with a cylindrical sleeve 27 made of a non-magnetic material around a magnet member 26 in which a large number of magnets are arranged, and the sleeve 27 is configured to rotate in the arrow X direction. To be done. Further, the toner cartridge 22 is attached to the main body frame 21 of the developing device,
The toner contained in the toner cartridge 22 is sent by the agitator 23 toward the developing roller 25. Then, the magnet member 2 of the developing roller 25
Toner is attached to the surface of the sleeve 27 by the magnetic force of 6, and the electrostatic latent image formed on the photoconductor drum 5 is rubbed by the ears of toner while the layer thickness of the toner is regulated by the blade member 30. , Let the development work.
In addition, at a predetermined position of the main body frame 22, a toner is provided.
A sensor 24 for detection is arranged so that the amount of toner in the toner cartridge can be monitored.

In the developing device 20 shown in FIG. 1, the magnet arranged in the magnet member provided on the developing roller has four magnetic poles S1 and N as shown in FIG.
1 and S2 and N2 are arranged with a phase difference of 90 °. In the developing roller, the blade member 30 is arranged at a portion corresponding to the S1 pole among the plurality of magnetic poles, and the toner spikes Th are caused by the blade member 30.
The layer thickness is regulated. Further, as described above, the toner whose layer thickness is regulated by the blade member is
The toner is transferred to the electrostatic latent image formed on the photosensitive drum by making the one pole portion correspond to the photosensitive drum, and the toner is transferred.
Try to form an image.

At the portion where the blade roller 30 presses the developing roller, the spike of the toner formed by the magnetic pole S1 is set to the width a as shown in FIG.
As shown in the graph of FIG. 4, the width of the spikes of toner is set on the surface of the sleeve at the value of 80% of the magnetic strength of the magnetic pole. In the example of the present invention, the width a of the magnetic pole causes a magnetic force for attracting the toner to act on the surface of the sleeve within a range of about 35 ° about the axis of the developing roller, and the blade member. The toner is pressed against the sleeve by 30 to set the thin layer of toner to a predetermined thickness and to perform the function of forming the spikes of the toner.

Therefore, in the above embodiment, the width a of the magnetic pole is
Is formed narrower than the conventional one, the length of the pressing plate 32 of the blade member 30 does not have to be restricted,
It is possible to suppress the generation of abnormal noise in the layer thickness regulating section. On the other hand, in the developing roller used in the conventional developing device, as shown in FIG. 3, the width b of the portion where the layer thickness is regulated by the blade member is set in the range of 45 °, for example. Had set. Therefore, as shown by the width b of the S pole in the graph of FIG. 4, a wide magnet is used to form the spikes Th of the toner on the surface of the developing roller with a wide width. When pressing the spiked part of the toner,
Since the blade member exerts a pressing action on the toner over a wide area, a large noise is generated at the layer thickness regulating portion.

As described above, as a means for setting the width of the spikes of the toner to be narrow at the portion where the blade member is pressed to form the thin layer of toner, as shown in the above embodiment. In addition, the width of the magnet of the magnet member can be set narrow. Then, in the portion that regulates the rising of the toner with respect to the sleeve of the developing roller, only the magnetic poles corresponding to the blade member may be configured to have a narrow width, or all the magnets arranged in the magnet member may be configured. Arbitrary means can be applied, such as a narrow one. In the developing device of the present invention, since the blade member acts on the narrow portion in the thin layer forming portion, the thin layer forming action is performed with an appropriate width without the friction action being performed on the wide portion. Therefore, a large noise is not generated in the toner spike control unit.

The developing device constructed as described above can be applied to an image forming apparatus such as a general electronic copying machine, but can also be applied to a printer as shown in FIG. it can. The example shown in FIG. 5 shows a case in which the layer thickness regulating means of the present invention is applied to the developing device 20 of a small laser printer-1. The rae
The printer 1 is provided with an image writing device 2 using a laser beam with respect to the photosensitive drum 5, and the writing device 2 outputs the image according to a command from an image information output device (not shown). -The image writing operation is performed by the beam. Around the photoconductor drum 5, a charging corotron 6, a developing device 20, a transfer / separation corotron 7 and a cleaning device 8 are arranged as in the case of an image forming apparatus using a general electrophotographic system. There is.

Then, after uniformly charging the photosensitive drum 5 by the charging corotron 6, the laser beam output from the writing device 2 is exposed.
An electrostatic latent image is formed, and the developing device 2 is applied to the electrostatic latent image.
The toner supplied from the developing roller 25 of 0 is attached to form a toner image. The toner image formed on the photoconductor drum 5 is transferred to a sheet by discharge by the transfer / peeling corotron 7, and the sheet carrying the toner image is conveyed toward the fixing device 15, Fixing device 15
Then, heat and pressure are applied to fix and make a copy, and the copy is discharged toward the discharge tray 16. Further, after the toner image is transferred onto the paper, the toner remaining on the surface of the photosensitive drum is scraped off by the blade of the cleaning device 8 and the surface of the photosensitive drum is cleaned. Toner of
Corresponds to image formation.

A paper feed cassette 10 is arranged below the main frame of the laser printer 1, and a paper is fed from the paper feed cassette 10 by a paper feed roller 11 and passed through a paper path 12. And feed it toward the image transfer section. A registrar device 13 is arranged immediately in front of the image transfer section to temporarily stop the sheet conveyed through the sheet path 12 to position the leading end of the sheet and correct the skew of the sheet. To act. After that, the registrar is driven in synchronism with the toner image formed on the photosensitive drum to transfer the toner image to a correct position on the paper. In the laser printer, the exhaust fan 17 is used in order to remove ozone generated by the charger, heat generated by the fixing device, heat generated by the motor of the writing device, and the like. Are arranged.

In the laser printer 1 constructed as described above, as the developing roller of the developing device 20, a means for rotating the sleeve on the surface of the magnet member is provided as shown in FIG. A blade member for controlling the layer thickness of the surface toner of the sleeve can be used. Further, as shown in FIG. 2, the pressing portion by the blade member is used to set the width of the layer thickness regulating portion to be narrow by using means for setting the width of the spike of toner to be narrow. Therefore, in the developing device used for the laser printer, it is possible to prevent abnormal noise from being generated at the pressing portion by the blade member, and reduce the noise level of the entire printer.

[0020]

Since the developing device of the image forming apparatus of the present invention is configured as described above, the toner adhesion width is controlled on the sleeve at the thin layer forming portion for the developing roller. Therefore, the width of the portion pressed by the blade member can be easily set by providing the means for regulating the width of the toner attracted to the surface of the sleeve by the magnet member. Therefore, by setting the width for rubbing the rising of the toner by the blade member to be narrow, it is possible to prevent the generation of abnormal noise at the friction portion.
When the width of the magnetic pole of the magnet member with respect to the surface of the sleeve is set to be narrow, it is not necessary to change the mechanism of the magnet member of the developing roller to a large width.
It is possible to configure an apparatus that is almost the same as the conventional developing roller. Then, by controlling the generation of abnormal noise in the layer thickness regulating section, it becomes possible to reduce noise and the like generated from the copying machine.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a developing device of the present invention.

FIG. 2 is an explanatory view showing the action of a magnet provided in the developing roller.

FIG. 3 is an explanatory diagram showing a state in which the width of the magnet is set wide.

FIG. 4 is a graph showing a width of a magnet and a state of action of magnetic force.

FIG. 5 is an explanatory diagram showing the configuration of a laser printer to which the developing device of the present invention can be applied.

FIG. 6 is an explanatory view showing the action of a blade member in a general developing roller.

FIG. 7 is an explanatory diagram of a layer thickness regulating function of toner spikes by a blade.

[Explanation of symbols]

1 laser printer, 5 photosensitive drum, 2
0 developing device, 22 toner cartridge, 25 developing roller, 26 magnet member, 27 sleeve, 30 blade member, 31 leaf spring member, 32
Pressing plate.

Claims (3)

[Claims] 1. A developing roller is arranged corresponding to a photosensitive drum, a sleeve is arranged around a magnet member provided on the developing roller, and toner is attracted to the surface of the sleeve by the magnetic force of the magnet member. In a developing device configured to adsorb and press the toner with a blade member to regulate the layer thickness of the toner, and to expose the toner toward the developing area of the photosensitive drum, the portion regulating the layer thickness with the blade A developing device for an image forming apparatus, characterized in that means for restricting the width of the toner attracted by the magnet member is provided. 2. A width of a magnet member corresponding to the blade member is set to be narrow at a portion where the thickness of the toner layer is regulated by the blade member, and a width of a spiked portion of the toner is regulated. 1. The developing device of the image forming apparatus described in 1. 3. In the magnet member provided in the portion corresponding to the blade member, with respect to the surface of the sleeve,
3. The image forming apparatus according to claim 1, wherein the action width of 80% of the magnetic force of the magnet member is set so that the angle is about 35 ° about the axis of the sleeve. Development device.