JPH02211482A - Image forming device - Google Patents

Abstract

PURPOSE:To stabilize image quality and to prolong the life of a photosensitive body by providing a cleaning means made of conductive materials which differ in shape and material in plural stages and eliminating the influence of residual toner on the photosensitive body at the time of exposure. CONSTITUTION:A cleaning member 109 consists of a sponge member 135a formed of conductive 'Moltopren(R)', etc., in a block shape and a brush 135b formed of conductive rayon, etc. The brush 135b is applied with a positive voltage. Then lump toner remaining on the photosensitive body 101 is leveled smoothly by the sponge member 135a and attracted to the brush 135b. the attracted toner is pushed to behind the brush 135b and stuck dispersedly on the surface of the photosensitive body 101. A memory phenomenon due to the remaining toner at the time of the exposure is precluded. Further, the photosensitive body is never flawed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus such as an electrophotographic laser printer or a copying machine, and particularly relates to toner remaining on an image carrier after transfer. This invention relates to improvements in cleaning means for cleaning.

(Prior Art) Image forming apparatuses such as electrophotographic laser printers use a developing device (gA) that supplies toner to an electrostatic latent image formed on a cylindrical photoreceptor, which is an image carrier, to make it visible. Attire! A transfer device is provided for transferring an image formed on the photoreceptor using toner onto a sheet of paper. Although most of the toner on the photoreceptor is transferred onto the paper by this transfer device, some toner remains on the photoreceptor.

The remaining state of the toner on the photoreceptor after the transfer is as shown in FIG. 11, in which there is a rough amount of toner remaining, and A indicates the case where normal transfer has been performed.

B is a case where the transfer is close to normal, but the transfer is slightly excessive, and the toner becomes positively charged with the opposite polarity by the transfer charger, which tends to occur when transferring solid black etc.
In addition, C is a case where toner remains in a lump due to insufficient transfer, which tends to occur when the paper is lifted off the transfer body during transfer due to carrier adhesion or paper wrinkles.Additionally, toner remaining after transfer in unexposed areas is left on the surface of the photoreceptor. Since the potential VO is lower than the developing bias vb applied to the developing device, it is electrostatically attracted to the developing device. On the other hand, since the surface potential of the photoreceptor has increased due to the exposure, the negatively charged toner does not return to the developing device and remains on the photoreceptor.

If the untransferred toner remaining on the photoconductor is uniformly scattered on the photoconductor as in cases A and B, the amount of laser light in the exposure process is sufficiently large;
Since the exposed area is sufficiently large compared to the size of the toner, even if toner adheres to the photoreceptor, it will not create a shadow from the exposure, and the negative potential on the surface of the photoreceptor will attenuate and a latent image will be formed. Ru. Moreover, as the unexposed area is reliably cleaned by the developing device as described above, there is no problem in forming a latent image. However, if toner remains in the form of a lump as in case C, This makes it difficult to clean everything, and positive memory is formed on the white background. Also, if this area corresponds to the next exposed area, the toner layer is thick and the diameter of the lump is large, so no light passes through, and the black background becomes Negative memory occurs.

In order to remove the above-described residual toner after transfer, a cleaner has conventionally been provided between the transfer device and the pre-exposure device on the outer periphery of the photoreceptor. Conventionally, this cleaner has been composed of a blade that comes into contact with the surface of the photoreceptor to scrape off the toner, and a collection box that collects the scraped toner.

(Problem H to be solved by the invention) However, according to the conventional cleaner as described above,
Since the toner remaining on the photoreceptor is scraped off into the collection box by a blade, it usually costs 2,000 yen.
After 0 to 3,000 copies have been made, the toner in the collection box becomes full and becomes unusable. For this reason, it is necessary to install a complicated recycling mechanism and collection box, and replace the collection box each time to replenish the toner.
There was a problem in that the construction became sloppy and the user's hands and clothes got dirty, making workability worse. Furthermore, depending on the type of equipment, the cleaner may have to be discarded each time. Furthermore, since the toner on the photoreceptor is scraped off by the blade, there is also the drawback that the surface of the photoreceptor is scratched.

The present invention has been made in view of the above circumstances, and has a simple structure that eliminates the influence of residual toner on the photoreceptor during exposure, stabilizes image quality, extends the life of the photoreceptor, and improves work efficiency. An object of the present invention is to provide an image forming apparatus that can improve performance.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes an image bearing member and a developing device configured integrally, and a cleaning means for cleaning toner remaining on the image bearing member after transfer. In the image forming apparatus, the cleaning means is formed in a plurality of stages, and these cleaning means are constructed of conductive members having different shapes and made of different materials.

(Function) According to the above means, the lump-like toner remaining on the image bearing member after transfer can be efficiently dispersed backward by the cleaning means of different types in multiple VL stages, and the residual toner can be easily dispersed at the time of exposure. Memory generation can be prevented. Therefore, a toner collection box is not required, and by integrally attaching the cleaning means to the developing device, the cartridge can be made smaller. Moreover, since the memory removing means provided in the cleaning means is formed of a soft member, the surface of the image carrier is not damaged, and the life of the image carrier can be extended.

(Embodiment) Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1 to 3.

In FIGS. 1 and 2, one mag roller 131 and two stirring rollers 132a, 132b are provided in the casing 133 of the developing device 104, with their axial directions parallel to each other. arrows a and b respectively
, and are driven to rotate in the c direction. Further, the casing 133 is filled with toner 134 which is a developer. A drum-shaped photoreceptor 101 is provided in this casing 133 in parallel to each of the rollers 131132, and is rotationally driven in the direction of arrow R by a drive source (not shown).

Furthermore, the gauging 133 is provided with a cleaning means 109 in parallel with the photoreceptor 101, and this cleaning means 109 includes a sponge-like member formed into a block shape of conductive maltbrene or the like, as shown in FIG. 135a and brushes 135b made of conductive rayon or the like are attached in parallel on the upstream and downstream sides, respectively. The lower ends of the sponge-like member 135a and the brush 135b are in contact with the outer periphery of the photoreceptor 101 in the quiz direction along the generatrix direction, and the width is wider than the maximum paper width to be used and the image area.

Further, a positive voltage is applied to the brush 135b.

Note that the reference numeral 141 shown in FIG. 1 is the incident position of the light incident on the photoreceptor 101 from the pre-exposure device 112, and the reference numeral 142 is the incident position of the light incident on the photoreceptor 101.
The incident position of the laser beam that enters the photoreceptor 101 from the latent image forming section 103, and the reference numeral 136 shown in FIG. 2 is the developing device 104.
This is a handle provided on the gauging 133 of.

Next, a case in which an embodiment of the present invention is applied to a laser printer will be described with reference to FIG.

FIG. 4 shows a schematic configuration of an electrophotographic monochrome laser printer.

This laser printer is electrically connected to a computer or a host system (external bag 3F) such as a word processor via a transmission device (not shown).
It receives dot image data from an external device and modulates the laser beam to write on the photoreceptor, and the written dot image data is developed and transferred onto paper.

That is, 100 is an apparatus main body, and a drum-shaped photoreceptor 101 is disposed within this main body 100, and this photoreceptor 101 is rotated in the direction of arrow R by a drive source (not shown).

At the periphery of the photoreceptor 101, along the rotation direction of the photoreceptor 101, a charge control type IF charger 102, an electrostatic latent image forming section 103,
A developing device 104 provided with the cleaning means 109
, a transfer charger 105, and a pre-exposure device 112 are arranged in this order, and the photoreceptor 101 is integrated with the developing device 104.

The main body 100 is provided with a paper feed cassette 106, and a paper feed roller 10 is provided from the paper feed cassette 106.
The paper with the recording ff# taken out in step 7 is transferred to the photoreceptor 10.
1 and the transfer charger 105, and the image transfer unit 1
After passing through 08 and a fixing device 118, the sheet is guided to a sheet discharge roller 113 and is discharged to a sheet discharge section 114.

The electrostatic latent image forming unit 103 includes a semiconductor laser oscillator (not shown) (such as a laser diode) that generates a laser beam modulated according to dot image data from an external device (not shown), and a laser output from this laser oscillator. A lens system (not shown) such as a collimator lens that focuses the beam light, a four-sided rotating mirror (polygon mirror) 116 that scans the laser beam focused by this lens system, and a high-speed rotating mirror 116. A rotating mirror motor 117, a lens 121 that correctly guides the laser beam scanned by the rotating mirror to the photoconductor, a reflecting mirror 119 that reflects the laser beam toward the photoconductor 101,
120, a beam photodetector (not shown) for detecting the laser beam scanned by the rotating mirror 116, and the like.

In such a configuration, when a print start signal is received from an external device, the photoreceptor 101 rotates and the photoreceptor 10
What about 1? For example, the surface potential e is
The IF voltage is uniformly applied to 600 V.

Next, when receiving dot image data from an external device,
The electrostatic latent image forming unit 103 outputs a laser beam modulated according to the dot image data, and the surface of the photoreceptor 101 that has been charged is scanned and exposed by the laser beam light. Forms a latent image on the surface. The electrostatic latent image formed on the photoreceptor 101 is developed into a toner image by being reversely developed by the developing device 104 having a magnetic roller 131 and stirring rollers 132a and t32b. Then, the toner image on the @light body 101 is transferred in the image transfer section 108 onto the paper fed m from the paper feed cassette 106.

The paper onto which the toner image has been transferred is conveyed to a fixing device 118, where the toner image is fixed, and then ejected to a paper ejection B114 by a paper ejection roller 113. Also, the transfer charger 105
After the toner image is transferred from the photoreceptor 101 to a sheet of paper (not shown), the toner remaining on the photoreceptor 1011 is generated by the process described later. H is cleaned by the cleaning means 109, and then from the light source of the exposure device 112, such as a red LED, @
The surface of the photoreceptor 101 is uniformly neutralized by the emitted light.

Next, the action of the cleaning means 109 is explained in FIGS. 5 to 10.
This will be explained with reference to the drawings. FIGS. 5 to 7 show the case of under-transferred toner, and FIGS. 8 to 10 show the case of over-transferred toner.

If there is a toner mass 150 on the surface of the photoreceptor 101 moving in the direction of arrow X as shown in FIG.
50 passes under the sponge-like member 135a, the toner mass 150 is smoothed out. Next, brush 135
When passing under b, the smoothed toner mass 150 is agitated by the brush 135b and dispersed onto the photoreceptor 101.
adheres to the surface of At this time, since a positive voltage is applied to the brush 135b, the toner mass 150 having a negative charge due to insufficient transfer is transferred to the brush 135b as shown in FIG.
35b. When the photoreceptor 101 further moves in the direction of the arrow X, the toner mass 1 sucked by the -degree brush 135b
50, since the brush 135b does not have the ability to hold toner,
As shown in FIG. 7, it naturally comes out behind the brush 135b. That is, the brush 135b is used to transfer insufficient toner mass 1.
50 is suctioned with n electric force, but since the amount of l/toner that can be attached to the brush 135b is small, and because the brush 135b is in contact with the photosensitive #101 in the width direction, the toner 150 that has been suctioned by n is gradually It adheres to other parts of the surface of the photoreceptor 101.

On the other hand, in the case of excessively transferred toner, the toner 151 is uniformly scattered on the transfer body 101 and the polarity is reversed, as shown in FIG.
It has the same polarity as positive. Therefore, even if the photoreceptor 101 moves in the direction of the arrow X and passes under the sponge-like member 135a and the brush 135b as shown in FIG. 9, it will not be attracted and will continue to be attracted to the photoreceptor 101.

That is, as shown in FIG. 10, the toner 151 passes directly under the sponge-like member 135a and the brush 135b,
It is located at the same position on the transfer material 101 as before passing. At this time,
The sponge-like member 135a and the brush 135b are made of a soft material, and are in contact with the photoconductor 101 in the quiz direction, that is, in a state of belly contact, and the contact pressure is extremely weak, so that the toner 151 is not moved. Therefore, the toner 151 is uniformly scattered as in the original state.

According to this embodiment, the transfer residual toner 1 on the photoreceptor 101
50 and 151 are uniformly scattered after passing under the cleaning means 109, and it is possible to prevent the occurrence of memory due to residual toner during exposure. Therefore, there is no need for a toner collection box as in the conventional case, and in addition, transfer #101, developing device 104 and cleaning means 109
can be integrated into a cartridge, making it possible to make the device smaller and lighter. Furthermore, since the sponge-like member 135a and the brush 135b are made of a soft material and are in contact with the photoreceptor 101 in the quiz direction, the life of the photoreceptor 101 can be extended and the image quality can be improved.

In the above embodiment, the sponge-like member 135a and the brush 13
Although the case where each number 5b is one is described, the number of these is not limited to one, and the member for #Ir1L as the cleaning means may be another conductive member, for example, a blade made of synthetic vIi fat. It may also be a combination of different types, such as or brushes.

〔Effect of the invention〕

As described above, according to the present invention, the lump-like toner remaining on the image bearing member 1 after transfer is cleaned by a plurality of stages of cleaning means of different shapes and materials. It is possible to prevent the occurrence of memory due to lumps of residual toner remaining on the % hill, eliminate the need for a toner collection box, make the device smaller and lighter by converting it into a cartridge, and extend the life of the image carrier. Image quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing essential parts of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of FIG. 1, and FIG.
FIG. 4 is a vertical sectional view showing a laser printer to which the cleaning means according to the present embodiment is applied, and FIGS. 5 to 10 are explanatory diagrams showing the operation of the present embodiment. , FIG. 11 is an explanatory diagram showing toner remaining on the image carrier. 101... Photoreceptor (image carrier). 104...Developer. 109...Cleaning means. 135a... Sponge-like member. 135b...Brush. 150.151...Toner

Claims (1)

[Claims] An image forming apparatus in which an image bearing member and a developing device are integrally constituted, and the image forming apparatus is provided with a cleaning means for cleaning toner remaining on the image bearing member after transfer, the cleaning means being formed in a plurality of stages, and An image forming apparatus characterized in that these cleaning means are constructed of conductive members having different shapes and different materials.