JPH02211485A - 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 blades 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 blades 135a and 135b, formed of soft members such as conductive rayon while the lower edges are formed irregularly, in parallel. Further, the downstream-side blade 135b is applied with a positive voltage. Further, lump toner remaining on the photosensitive body 101 is leveled smoothly by the blade 135a and attracted to the blade 135b. The attracted toner is pushed out to behind the blade 135b and stuck dispersedly on the photosensitive body 101. A memory phenomenon due to the residual toner at the time of exposure is precluded and 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 are equipped with a developing device that supplies toner to an electrostatic latent image formed on a cylindrical photoreceptor, which is an image carrier, to make it visible. 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 X, 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 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 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;
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.

(Issue to be solved by the invention! iI) However, according to the conventional cleaner as mentioned above,
Since the toner remaining on the photoreceptor is scraped off into the collection box by a blade, it usually takes 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 number-of-times mechanism and a collection box and replace the collection box each time to collect the toner, which makes the structure complicated and makes the user's hands and head 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, the blade scrapes off the toner on the photoreceptor, which has the disadvantage of damaging the surface of the photoreceptor.

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 constituted by conductive blades.

(Function) According to the means described in 1, the lump-like toner remaining on the image bearing member after transfer can be dispersed backward by the blade provided in the cleaning means of several stages Ii, and the remaining toner can be removed during exposure. It is possible to prevent the occurrence of memory problems caused by 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. Furthermore, by forming the cleaning means from a soft member, the surface of the image carrier is not damaged and its life 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 4.

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 gauging 133 is filled with toner 134 which is a developer. A drum-shaped photoreceptor 101 is provided in the 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).

Further, a cleaning means 109 is provided in the casing 133 in parallel to the photoreceptor 101, and the lower edge of the cleaning means 109 is formed into an uneven shape using a soft material such as conductive rayon, as shown in FIG. A pair of blades 135a, 135b are attached in parallel. The lower ends of these blades 135a and 135b are attached to the photoreceptor 10.
It is in contact with the outer periphery of 1 in the quiz direction along the generatrix direction,
The width is wider than the maximum paper width to be used and the image area. Further, a positive voltage is applied to the blade 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 photoconductor 101 from the pre-exposure device 112, and the reference numeral 142 indicates the incident position of the laser beam incident on the photoconductor 101 from the electrostatic latent image forming section 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 10 is rotated in the direction of arrow R by a drive source (not shown).

Along the rotation direction of the photoreceptor 101! F electric sub-control type charging charger 102, 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 originally arranged, 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 a recording medium taken out in step 7 is transferred to the photoreceptor 10.
1 and the transfer charger 105, and the image transfer portion J
After passing through O8 and the fixing device 118, the sheet is guided to a sheet discharge roller 113 and is discharged to a sheet discharge section 114.

The n-electrolayer 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 uniformly electrically charged by the IF electrical device 102 to a surface potential of approximately e 600 V, for example.

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 laser beam scans and exposes the surface of the photoconductor 101 subjected to IF electrolysis. forms an electrostatic latent image on the surface of the @The WII electric latent image formed on the light body 101 is the mag roller 131, tt! matter roller 132a, t32
The toner image is developed by reversal development by a developing device 104 having a 4 and a photoreceptor 101.
The upper toner image is transferred to the paper 1 conveyed from the paper feed cassette 106 in the image transfer section 108 .

The paper onto which the toner image has been transferred is conveyed to a fixing device 118, where the toner image is fixed, and the paper is ejected to a paper ejection unit 114 by the TK 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 insufficiently transferred toner, and FIGS. 8 to 10 show the case of toner that has not been transferred.

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 upstream blade 135a,
The toner mass 150 having a negative charge due to insufficient primary transfer, which is smoothed, is attracted to the downstream blade 135b to which a positive voltage is applied, as shown in FIG. As the photoreceptor 101 further moves in the direction of the arrow X, the toner mass 150 attracted by the blade 135b naturally comes out behind the blade 135b as shown in FIG. It's coming. That is, the blade 135b attracts the insufficiently transferred toner mass 150 with electrostatic force, but since the amount of toner that can adhere to the blade 135b is small, the blade 135b also attracts the toner mass 150 that is insufficiently transferred.
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 . At this time, since the lower edge of the blade 135 is uneven, the toner mass 150 is not scraped off.
The surface of the photoreceptor 101 will not be damaged.

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 toth and has reversed polarity, which is the same positive polarity as the blade 135b. Therefore, even if the photoreceptor Lot moves in the direction of the arrow X and passes under the blade 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. As shown, the toner 151 passes directly under the blade 135b and remains at the same position on the transfer material 101 as before passing. At this time, since the blade 135b is made of a soft material and contacts the photoreceptor 101 at multiple locations in the width direction, that is, in a state of belly contact, the contact pressure is extremely weak, so the toner 151 is not moved. Therefore, the toner 151 is uniformly scattered, which is 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 blade 135, and it is possible to prevent the generation of memory due to residual toner during exposure. Therefore, there is no need for a toner collection box like in the past, and the transfer body 10
1. 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 device. Furthermore, since the blade 135 is made of a soft material and contacts 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, a case has been described in which the number of blades 135 provided in the cleaning means 109 is two, but the number of blades 135 may be three or more.

〔Effect of the invention〕

As explained above, according to the present invention, the lumpy toner remaining on the image carrier 1 after transfer is smoothed and dispersed by the blade, so that the lumpy toner remaining on the image carrier 1 is smoothed and dispersed. It is possible to prevent memory generation due to residual toner, eliminate the need for a toner collection box, make the device smaller and lighter by using a cartridge, and extend the life of the vf body, improving image quality. can be done.

[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 diagonal #L view of FIG. 1, and FIG. 4 is a vertical sectional view showing a laser printer to which the cleaning means according to the present embodiment is applied, FIGS. 5 to 10 are explanatory diagrams showing the operation of the present embodiment, and FIG. 11 is an image bearing FIG. 3 is an explanatory diagram showing toner remaining on the body. 101... Photoreceptor (@carrier) 5 104... Developing device. 109...Cleaning means. 135a, 135b...Blades. 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 conductive blades.