JPH02211483A - 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 brushes 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 brushes 135a and 135b formed of conductive soft members and the downstream side brush 135b is applied with a positive voltage. Then lump toner remaining on the photosensitive body 101 is leveled smoothly by the brush 135a and then attracted to the brush 135b. The attracted toner is pushed out to behind the brush 135b and stuck dispersedly on the photosensitive body 101. A memory phenomenon due to the residual toner at the time of the exposure can be precluded. Further, the brushes 135 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 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) An image forming apparatus such as an electrophotographic laser printer has an IJL formed on a cylindrical photoreceptor that is an image carrier.
A developing device that supplies toner to the latent image to make it visible, and a transfer device that transfers the image formed with toner on the photoreceptor onto paper! is provided. 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.

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.
Mana C is when toner remains in lumps due to insufficient transfer, and tends to occur when paper is lifted off the transfer body during transfer due to carrier adhesion or paper wrinkles.Also, residual toner 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 attracted to the developing device like a flit. 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 exposure, and the negative potential on the surface of the photoreceptor attenuates, forming a latent image. be done. 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.

(MM to be solved by the invention) However, according to the conventional cleaner as described above,
The structure is such that the toner remaining on the photoreceptor is scraped off into the collection box by a blade, so it usually takes 2,000
After making 3,000 to 3,000 copies, the toner in the collection box becomes full and becomes unusable. For this reason'
MM collection mechanism and collection box are installed, and the collection box must be replaced each time to collect toner.
14M becomes complicated, and the user's hands and clothes become dirty, resulting in poor workability. 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 that are integrally configured, and a cleaning means for cleaning toner remaining on the image bearing member after transfer. In the image forming apparatus, the cleaning means are formed in several stages, and these cleaning means are constructed of conductive brushes.

(Function) According to the means described in 1, the lump-like toner remaining on the image holding body after transfer can be dispersed backward by the brush provided in the cleaning means in multiple stages, and the residual toner can be dispersed at the time of exposure. Memory generation can be prevented. Therefore, a toner collection box is not required, and the cleaning means is integrally attached to the developing device, thereby making it possible to form a compact cartridge. 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 132 are included in the casing 133 of the current device 104.
a and 132b are provided with their axial directions parallel to each other, and are rotationally driven in the directions of arrows a, b, and c, respectively, by a drive source (not shown). Further, the casing 133 is filled with toner 134 which is a developer. In this casing 133, a drum-shaped photoreceptor 101 is attached to each of the rollers 13.
1.132, and is rotationally driven in the direction of arrow R by an ig drive source (not shown).

Furthermore, a cleaning means 109 is provided in the casing 133 in parallel to the photoreceptor 101, and as shown in FIG. 13
5b are attached in parallel. These brushes 13
The lower ends of 5a and 135b are in contact with the outer periphery of the photoreceptor 101 in the width 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 on the downstream side.

In addition, the reference numeral 141 shown in FIG. 1 is the incident position 1 of the light incident on the photoreceptor 101 from the pre-exposure device 112, the reference numeral 142 is the incident position of the laser beam incident on the photoreceptor 101 from the #electronic layer image forming section 103, Reference numeral 136 shown in FIG. 2 indicates 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 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 a main body of the apparatus, and a drum-shaped photoreceptor 101 is disposed inside the main body 1°O, and this photoreceptor 101 is rotated in the direction of arrow R by a drive source (not shown).

Around the photoconductor 101, along the direction of rotation thereof, a charge control type charging charger 102, an electrostatic latent image forming section 103, a developing device 104 having the cleaning means 109,
A transfer charger 105 and a pre-exposure device 112 are arranged in this order, and the photoreceptor 1.degree. is integrated with the developing device 104.

Book #100 is provided with a paper feed cassette 106, and this paper feed cassette 106 is equipped with a paper feed roller 10.
The paper as a recording medium taken out in step 7 is exposed to light #101.
and the transfer charger 105, and the image transfer unit 10
After passing through 8 and a fixing device 118, the sheet is guided to a sheet discharge roller 1]3 and is discharged to a sheet discharge section 114.

The electrostatic latent image forming section 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 beam outputted from this laser oscillator. A lens system (not shown) such as a collimator lens that condenses the laser beam, for example a four-sided rotating mirror (polygon mirror) 116 that scans the laser beam condensed by this lens system, and this rotating mirror 116. a mirror motor 1171 that rotates at high speed; 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 in the direction of the photoconductor 10;
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, photosensitive #%101 rotates and photosensitive #1
01 is uniformly charged by the charging IFt device 1o2 so that the surface potential of S is about θ600V.

Next, when receiving dot image data from an external device,
The 1lit latent image forming section 103 outputs a laser beam modulated according to the dot image data, and scans and exposes the -H surface of the photoreceptor Lot with the laser beam, thereby exposing the surface of the photoreceptor 101. Forms an electrostatic latent image on the surface. @1aW1@ formed on the light body 101 is a mag roller 131, illll-ra 132a, 132
The toner image is formed into a toner image through reversal development by the developing device 104 having the toner b. and photoreceptor 101
The upper toner image is transferred onto the paper conveyed from the paper feed cassette 106 in the image transfer unit tO8. The paper with the toner image transferred is transferred to the fixing device 118!
f to fix the toner image, and then the paper ejection roller 113
The paper is ejected to the paper ejection unit 114. Further, after the toner image is transferred from the photoreceptor 101 to a sheet of paper (not shown) by the transfer charger 105, the toner remaining on the photoreceptor 101 is cleaned by the cleaning means 109 by the action described later, and then the pre-exposure of the red LED etc. The surface of the photoreceptor 101 is uniformly neutralized by light emitted from the light source of the container 112 .

Next is the creation of cleaning means 109! ■ from Figure 5 to Figure 1
This will be explained with reference to FIG.

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 lump 150 on the surface of the photoreceptor 101 moving in the direction of arrow X as shown in FIG.
When the toner mass 150 is smoothed when it passes under the upstream brush 135a, the toner mass 150 having a negative charge due to insufficient transfer is transferred to the brush to which a positive voltage is applied, as shown in FIG. 135b. Photoreceptor 1
01 further moves in the direction of the arrow X, -degree brush 135b
Since the brush 135b does not have the ability to hold toner, the toner mass 150 sucked in naturally comes out behind the brush 135b as shown in FIG. That is, the brush 135
In b, the insufficiently transferred toner mass 150 is attracted by electrostatic force,
Because the amount of toner that can adhere to the brush 135b is small, and because the brush 135b is in contact with the photoreceptor 101 in the width direction, the toner 150 that has been sucked out gradually adheres to other parts of the surface of the photoreceptor 101. do.

On the other hand, in the case of excessively transferred 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 brush 135b. Therefore, even if the photoreceptor 101 moves in the direction of the arrow X and passes under the brush 135b as shown in FIG. 9, it will not be attracted and will continue to be attracted to the photoreceptor 101, as shown in FIG. So, toner 151 is brush 1
It passes directly under 35b and is at the same level 1 on the transfer material 101 as before passing. At this time, the brush 135b is made of a soft material and is in contact with the photoreceptor 101 in the quiz direction, that is, in a belly-resting state, so that the contact pressure is extremely weak.
Toner 151 is never moved, so toner 1
51 are 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 brush 135, and it is possible to prevent the occurrence of memory due to residual toner at the time of bottom light. Therefore, there is no need for a conventional toner collection box, and the transfer body 101
, the cleaning device 104 and the cleaning means 109 can be integrated into a cartridge, making it possible to reduce the size and weight of the device. Further, since the brush 135 is made of a soft material and corrodes 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, a case has been described in which the number of brushes 135 provided in the cleaning means 109 is two, but the number of brushes 135 may be 3a or more.

〔Effect of the invention〕

As explained above, according to the present invention, the blocky toner remaining on the image carrier 1 after transfer is dispersed with a brush, so that memory damage caused by the blocky residual toner remaining on the image carrier 1 is It is possible to prevent this, eliminate the need for a toner collection box, and reduce the size of the device by converting it into a cartridge/yield.
1, it is possible to lengthen the life of the carrier (11) and improve the quality of the image.

[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. 24 is a perspective view of FIG. 1, and FIG. 3 is an exploded oblique view showing the cleaning means of FIG. 1. , FIG. 4 is a #11 sectional view showing a laser printer in which the cleaning means according to this embodiment is used, and FIGS. 5 to 10 are explanatory diagrams showing the operation of this embodiment. Figure i11 is an explanatory diagram showing toner remaining on the image carrier. 101... Photoreceptor (image carrier). 04...Developer. 09...Cleaning means. 35a, 135b=...brush. 50.151...Toner agent, private patent attorney Hidekazu Miyoshi 101.! 1 t of light (@+u holding body) 104 ・Saltware 5]Osu...Cleaning procedure I', 15. t, I 1'5b...Brush 150.1
51...Toner 102/ / Figure 5 Figure 7 Figure 1 Figure 2 Figure 8 Figure 10 Figure 11

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 conductive brushes.