JPH02211480A - 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 consisting of conductive sponge members in plural stages and eliminating the influence of residual toner on the photosensitive body at the time of exposure. CONSTITUTION:The cleaning means 109 consists of a couple of sponge members 135a and 135b formed of conductive soft members. Further, the upstream-side sponge member 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 then attracted by the sponge member 135b. Therefore, the attracted toner is pushed out to behind the sponge member 135b and stuck dispersedly on the photosensitive body 101. Therefore, a memory phenomenon due to the residual toner at the time of the exposure is precluded. Further, both the members 135a and 135b are formed of the soft members, so the photosensitive body is never flawed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application!'f) The present invention relates to an image forming apparatus such as an electrophotographic laser printer or a copying machine, and particularly relates to an image forming apparatus such as an electrophotographic laser printer or a copying machine. The present invention relates to an improvement in cleaning means for cleaning residual toner.

(Prior Art) An image forming apparatus such as an electrophotographic laser printer is equipped with a developing device that supplies toner to an N-electrolayer image formed on a cylindrical photoreceptor as an image carrier to form an M image. 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 are various remaining toner states, and in FIG.

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 rings 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 exposure, the toner remaining after transfer in the exposed area 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;
Because the exposed area is sufficiently large compared to the size of the toner, even if toner adheres to the photoreceptor, it does not create a shadow from the exposure, and the negative potential on the surface of the photoreceptor is attenuated to form a latent image. 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.

(Problems to be Solved by the Invention) However, according to the conventional cleaners as described above,
The structure is such that the toner remaining on the photoreceptor is scraped off into the collection box with a blade, so it costs 2,000 yen to operate.
After making 3,000 to 3,000 copies, the toner in the collection box becomes full and becomes unusable. For this reason, M
A complicated collection mechanism and collection box are installed, and the collection box must be replaced each time to collect the toner, which results in a complex structure and makes the user's hands and clothes dirty, resulting in poor work efficiency. There was a problem. 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. 5. To provide an image forming apparatus that can improve performance.5. With the goal.

[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 made of conductive sponge-like members.

(Function) According to the above means, the lump-like toner remaining on the carrier after transfer can be dispersed backward by the sponge-like member provided in the multiple stages of cleaning means,
It is possible to prevent memory from occurring due to residual toner during exposure. 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 cleaning means is formed of a soft material, it does not damage the surface of the image carrier, making it possible to extend its life.

(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 4.

In FIGS. 1 and 2, one mag roller 131 and two stirring rollers 132a, L32b are provided in the gauging 133 of the current device 104 with their axial directions parallel to each other. Depending on the source, arrow a,
Rotationally driven in directions b and c. Further, the casing 133 is filled with toner 134 which is a developer. A drum-shaped photoreceptor 101 is provided in this gauging 133 in parallel to each of the rollers 131 and 132, and is rotationally driven in the direction of arrow R by a drive source (not shown).

Further, the gauging 133 is provided with a cleaning means 109 in parallel with the photoreceptor 101, and this cleaning means 109 includes a pair of sponge-like members made of a soft material such as conductive maltbrene as shown in FIG. 1
35a and 135b are attached in parallel. The lower ends of these sponge-like members 135a and 135b are connected to the photoreceptor 1.
It is in contact with the outer periphery of 01 in the width direction along the generatrix direction, and its width is wider than the maximum paper width to be used and the image area. Further, a positive voltage is applied to the sponge-like member 135b on the downstream side.

In addition, the reference numeral 141 shown in FIG. 1 indicates the incident position of the light incident on the photoreceptor 101 from the pre-exposure device 112, and the reference numeral 142 indicates the incident position of the laser beam incident on the photoreceptor #101 from the electrostatic latent image forming unit 103. Reference numeral 136 shown in FIG. 2 is the developing device 104.
This is a handle provided on the casing 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 device) such as a word processor via a transmission device (not shown), receives dot image data from the external device, and emits a laser beam. By modulating it, writing is performed 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).

Around the photoconductor 101, there is a swap along the rotation direction of the photoconductor 101.
M-shaped 11! IFtH102 for Ft, nt latent a forming part 1
03, 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 in the paper feed cassette 106.
The paper as a recording medium taken out in step 7 is transferred to the photoreceptor 101.
and the transfer charger 105, and the image transfer unit 10
8 and a fixing device 11'8, 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
1 is charged with a surface potential e by the charging IFt device 102.
It is uniformly charged to 600 volts.

Next, when receiving dot image data from an external device,
11, the latent image type vL unit 103 outputs a laser beam modulated according to the dot and image data, and the surface of the charged photoreceptor 101 is scanned and exposed by the laser beam, thereby exposing the photoreceptor 101 to the photoreceptor 101. An electrostatic latent image is formed on the surface of 101. n ML formed on the photoreceptor 101
The latent image is formed by the mag roller 131, stirring rollers 132a, 13
The toner image is formed into a 1° image by being reversely developed by the developing device 104 having the 2b. and photoreceptor 1
The toner image on No. 01 is transferred by the image transfer unit 108 onto the paper conveyed 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 section 114 by a paper ejection roller 113. Also transfer charger 10
After the toner image is transferred from the photoreceptor 101 to a sheet (not shown) by step 5, the toner remaining on the photoreceptor 101 is cleaned by a cleaning means 109 by the action described later, and then the toner is removed by a pre-exposure device 112 such as a red LED. The surface of the photoreceptor 101 is uniformly neutralized by the light emitted from the light source.

Next, the action of the cleaning means 109 is explained in FIGS. 5 to 10.
This will be explained with reference to the figures.

5 to 7 show the case of under-transferred toner, and FIGS. 8 to 10 show the case of over-transferred toner.

When there is a toner mass 150 on the surface of the photoreceptor 101 moving in the direction of arrow X as shown in FIG. 5 - this toner mass 1
When the toner 50 passes under the upstream sponge-like member 135a, the toner mass 150, which is smoothed and has a negative charge due to insufficient transfer, is applied with a positive voltage as shown in FIG. downstream sponge-like member 135
It is attracted to b. As the photoconductor 101 further moves in the direction of arrow It comes out behind the member 135b. That is, the sponge-like member 135b attracts the insufficiently transferred toner mass 150 by electrostatic force, but since the amount of toner that can adhere to the sponge-like member 135b is small, the sponge-like member 135b also
Since the toner 150 is in contact with the photoreceptor 101 in the width direction, the toner 150 that has been attracted by the toner 150 gradually adheres to other parts of the surface of the photoreceptor 101 .

On the other hand, the transcription is too much! In the case of No. 11 toner, as shown in FIG. 8, the toner 151 is uniformly scattered on the transfer body 101 and has reversed polarity, and has the same positive polarity as the sponge-like member 135. Therefore, even if the photoreceptor 101 moves in the direction of arrow X and passes under the sponge-like member 135 as shown in FIG. As shown in FIG. 2, the toner 151 passes directly under the sponge-like member 135 and remains at the same position on the transfer material 101 as before passing. At this time, the toner 151 is not moved because the sponge-like member 135b is made of a soft material and is in contact with the photosensitive member #101 in the width direction, that is, in a state of belly contact, and the contact pressure is extremely weak. Therefore, the toner 151 is uniformly scattered.

According to this embodiment, the transfer residual toner 1 on the photoreceptor 101
50 and 151 are uniformly scattered after passing under the sponge-like member 135, and it is possible to prevent the occurrence of memory due to residual toner during exposure. Therefore, unlike the conventional toner collection box, there is no need for it, and the transfer body 101, the developing device 104, and the cleaning means 109 can be integrated into a cartridge, making it possible to reduce the size and weight of the apparatus. Moreover, since the sponge-like member 135 is formed of a soft material and contacts the photoreceptor 101 in the width direction, the life of the photoreceptor 101 can be extended and the image quality can be improved.

In the above embodiment, the cleaning means 109 is provided with two sponge-like members 135, but the number of sponge-like members 135 may be three or more.

〔Effect of the invention〕

As explained above, according to the present invention, since the lump-like toner remaining on the image bearing member 1 after transfer is smoothed and dispersed with a sponge-like member, the toner remaining on the image bearing member 1 is smoothed and dispersed. It is possible to prevent memory generation due to residual toner in the form of lumps, eliminate the need for a toner collection box, make the device smaller and lighter by using a cartridge, and extend the life of the image carrier and improve image quality. can be done.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing the main parts of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the first factor, and FIG. 3 is a perspective view of the first factor.
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, 135b... Sponge-like members. 150.151...Toner

Claims (1)

[Claims] An image forming apparatus in which an image bearing member and a developing device are integrally constituted, and a cleaning means is provided 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 constituted by a sponge-like member having conductivity.