JPH02211486A - Image forming device - Google Patents

Abstract

PURPOSE:To stabilize image quality and to prolong the life of a photosensitive body by forming a cleaning means in plural stages and eliminating the influence of residual toner on the photosensitive body at the time of exposure. CONSTITUTION:The cleaning means 109 is fitted with the couple of brushes 135a and 135b, formed of soft members such as conductive rayon, in parallel. The downstream-side brush 135b is applied with a positive voltage. 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 is therefore precluded. Both the brushes 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!) 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 a cleaning means for cleaning toner.

(Prior Art) Image forming apparatuses such as electrophotographic laser printers use a developer that supplies toner to an n-electrode layer image formed on a cylindrical photoreceptor, which is an image carrier, to form a surface image. A transfer device is provided for transferring an image formed with toner on a photoreceptor 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 close to normal transfer, but the transfer is a bit stinging, and the transfer charger causes the toner to become positively charged with reverse 41i characteristics, which tends to occur when transferring solid rings, etc. This is a case where a lump-like appearance is left due to insufficient transfer, and is likely to occur when the paper is lifted off the transfer body during transfer due to carrier adhesion or paper wrinkles. The untransferred toner in the unexposed area is electrostatically attracted to the developer because VO on the surface of the photoreceptor is lower than the developing bias vb applied to the developer. 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 current Is 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 last exposed area is reliably cleaned by the developing device as mentioned above, there is no problem in forming a latent image. However, if toner remains in a lump like in case C, the developing device 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 that Qming tries to solve) However, according to the conventional cleaners as mentioned above,
Since the toner remaining on the photoconductor is scraped off into the collection box with a blade, it usually takes 2,000 yen.
After making 3,000 to 3,000 copies, the toner in the collection box becomes full and becomes unusable. For this reason a
A complicated collection mechanism and collection box were installed, and the collection box had to be replaced each time to collect toner, resulting in 831
7 is complicated, and the user's hands and head become dirty, which impairs work efficiency. 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 that are integrally configured, and a cleaning means for cleaning toner remaining on the image bearing member after transfer. Equipped with image forming bag! The cleaning means is formed in multiple stages.

(Function) According to the above means, the lump-like toner remaining on the image carrier after transfer can be dispersed onto the image carrier by the multiple stages of cleaning means, and the residual toner causes memory generation during exposure. can be prevented. Therefore, there is no need for a toner collection box, and by integrally attaching the cleaning means to the developing device, it is possible to create a compact cartridge.4Moreover, by forming the cleaning means from a soft member, the surface of the image carrier will not be damaged. Longer life is possible.

(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, 132b are provided in the casing 133 of the current @ device 104, with their axial directions parallel to each other, and a drive source (not shown) arrows a and b respectively
, and are driven to rotate in the c direction. Furthermore, the casing 133 is filled with toner 134 which is currently used. A drum-shaped photoreceptor 101 is provided in this casing 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). A cleaning means 109 is provided in parallel, and this cleaning means 1
A pair of brushes 135a and 135b made of a soft material such as conductive rayon as shown in FIG. 3 are attached to the brush 09 in parallel. These brushes 135a, 1
The lower end of the photoreceptor 101 is in contact with the outer periphery of the photoreceptor 101 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. Also, downstream brush 1
A positive voltage is applied to 35b.

Note that the reference numeral 141 shown in FIG.
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 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 photoreceptor 101, a charging control type charger 102.
3. Developing device 1 provided with preshrinkage cleaning means 109
04, 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 as the recording body taken out in step 7 is exposed to #10 photosensitive material.
1 and the transfer charger J, 05, and after passing through the image transfer section 108 and the fixing device 118, the sheet is fed to the discharge roller 11.
3 and is discharged to the paper discharge section 114.

The n@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 a supercharger 102 for IFt, for example, the surface potential θ
1F uniformly so that it is 600v! be done.

Next, when receiving dot image data from an external device,
The n-electrolayer image forming unit 103 outputs a laser beam modulated according to the dot image data, and the surface of the photoreceptor 101 that is charged is scanned and exposed to the laser beam, thereby forming an image of the photoreceptor 101. nt latent image is formed on the surface. A cape formed on the photoreceptor 101! The latent image is Magrolla 131, tt! The rabbit is developed by being reversely developed by the developer 104 having stirring rollers 132a and 132b.

It is converted into a toner image. The toner image on the photoreceptor 101 is transferred to the paper feed cassette 10 in the image transfer section 108.
The image is transferred onto the paper conveyed from 6.

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, the transfer charger 105
After a toner image is transferred from the photoreceptor 101 to a sheet of paper (not shown), the toner remaining on the photoreceptor 101 is cleaned by a cleaning means 109 according to the action described later, and then the toner is cleaned by a cleaning means 109 using 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 hm of the cleaning means 109 is shown in FIGS. 5 to 10.
This will be explained with reference to the figures.

Figures 5 to 7 show cases of under-transferred toner, and Figures 8 to 10 show cases of over-transferred toner. II This is the case of 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.
50 is smoothed by the brush 135a on the upstream side and passes under the brush 135b on the downstream side, the toner mass 150 having a negative charge due to insufficient transfer is applied with a positive voltage as shown in FIG. It is attracted by the brush 135b. When the Ii & light body 101 further moves in the direction of the arrow X, the toner mass 150 attracted by the -degree brush 135b naturally moves behind the brush 135b as shown in FIG. come out. That is, the brush 135b attracts the insufficiently transferred toner mass 150 with electrostatic force, but 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 mass 150 is attracted by - degree. Toner 1
50 gradually adheres to other parts of the surface of the photoreceptor 101.

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
35b and is at the same position on the transfer material 101 as before A″A. At this time, the brush 135b is made of a soft material, and the brush 135b is attached to the photoreceptor 101 in the with direction, that is, a belly pad-shaped portion. Since the contact pressure is extremely weak, the toner 151 is not moved, and therefore the toner 151 is uniformly scattered.

According to this embodiment, the transfer array toner 1 on the photoreceptor 101 is
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 during exposure. Therefore, there is no need for a conventional toner collection box, and the transfer body 101
, the developing device 104 and the memory removing 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 is in contact with the photoreceptor 101 in the quiz direction, the brush 135 is
1 and improve image quality.

In the above embodiment, a case has been described in which two brushes 135 are provided in the cleaning means 109, but the number of brushes 135 may be three or more.

Further, in the above embodiment, a case has been described in which the cleaning means 109 is composed of brushes 135a and 135b, but this cleaning means 109 includes a blade 135c as shown in FIG. 12 and a sponge-like member 135d as shown in FIG. These brushes 135 may also be
a, 135b, blade 135C, sponge-like member 13
5d may be configured with any number and any combination of the elements, and the material and shape are not particularly limited. Furthermore, the behavior of these components may be changed or at least a portion may be moved in the axial direction of the image carrier. Also, as shown in FIG. 14, 1. A sheet 137 for preventing toner scattering may be provided near the cleaning means 109 to prevent toner from scattering around the cleaning means 109, as shown in FIG.
A sheet guide 138 may be provided on the upstream side of 09 to prevent sheets from being caught in the cleaning means 109.

〔Effect of the invention〕

As explained above, according to the present invention, @the carrier, the developing device, and the memory removing means formed in multiple stages can be integrated into II.
I*, it is possible to prevent the occurrence of memory due to lump-like residual toner remaining on the image carrier, eliminate the need for a toner collection box, and make the device smaller and lighter by using a cartridge. It can extend the lifespan of the body and improve the quality of images.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing main 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 cross-sectional view showing a laser printer to which the cleaning device according to the present embodiment is applied, and FIGS. 5 to 10 are explanations showing the operation of the present embodiment. FIG. 2 FIG. 11 is an explanatory view showing toner remaining on the image carrier, and FIGS. 12 to 15 are perspective views and side views showing other embodiments of the present invention. 101...Photoreceptor (tR carrier). 104...Developer. 109...Cleaning means. 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, and the cleaning means is formed in a plurality of stages. An image forming apparatus characterized by: