JPH07261618A - Image forming device - Google Patents

Abstract

PURPOSE:To always obtain a constant image by using a material painted for color selected in accordance with the luminescent color of a discharge lamp, as a toner scattering preventing material. CONSTITUTION:A cleaning blade 115 and the toner scattering preventing member 118 for preventing toner scraped by the cleaning blade 115 from being scattered to the discharge lamp 117 are arranged around a photoreceptor drum 103. The top end of the toner scattering preventing member 118 comes into contact with the surface of the photoreceptor drum 103 and located in the optical path of discharging light from the discharge lamp 117 to make up a fixed ratio in the irradiation width of the discharging light. Therefore, the drum 103 is irradiated with the discharging light in such a manner that the top end of the toner scattering preventing member 118 transmits the discharging light. By such a constitution, since the preventing member 118 composed of a urethane sheet colored black is used, even if the number of copies is increased, an excellent image can be always formed without changing the quantity of the transmitted discharging light and a surface potential.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to improvement of a developer scattering prevention member that prevents scattering of the developer removed from the surface of the image carrier after transfer.

[0002]

2. Description of the Related Art In an electrophotographic apparatus such as an electronic copying machine or a laser printer, a toner is scattered inside the apparatus, which causes a problem that the inside of the apparatus is soiled or an image is stained with an image. is there. On the other hand, various measures for preventing toner scattering are applied to the developing device, the photosensitive drum, and the like.

As one of such measures, when the toner remaining on the photosensitive drum after the transfer is removed by a cleaning blade, the removed toner is prevented from scattering to prevent scattering. A toner scattering prevention member is provided in contact with the photosensitive drum downstream of the rotating blade in the rotating direction of the photosensitive drum.

[0004]

A toner provided downstream of the cleaning blade in the direction of rotation of the photosensitive drum.
As the scattering prevention member, a transparent or translucent member has been conventionally used. However, this toner scattering prevention member is necessarily arranged near the static elimination lamp due to structural problems of the apparatus, and its position crosses a part of the optical path of the static elimination light. Therefore, a part of the static elimination light is applied to the photoconductor drum in a form of passing through the toner scattering prevention member, so that the photoconductor drum is neutralized.

In such an image forming apparatus, as the life of the apparatus advances, a toner which is initially transparent or translucent is used.
The scattering prevention member is discolored due to temperature changes (due to use environment of the apparatus main body, changes in the photosensitive drum, etc.) and ozone generated in the machine. Further, the toner that is scattered may contaminate the toner, or the toner that remains on the photoconductor drum may contaminate the portion in contact with the photoconductor drum.

When the toner scattering prevention member discolors or is contaminated by the toner as described above, the amount of the static elimination light reaching the photosensitive drum changes from when it is transparent or translucent, and therefore the photosensitive member The surface potential of the drum changes. As a result, problems such as fogging on the image, crushed characters, and insufficient toner consumption occur. An object of the present invention is to provide an image forming apparatus capable of eliminating a change in the amount of static elimination light and thereby always forming a good image.

[0007]

SUMMARY OF THE INVENTION The present invention comprises an image carrier and
A means for forming an electrostatic latent image on the image carrier, a developing means for supplying a developer to the image carrier to develop the latent image on the image carrier, and a transfer material for transferring the developed developer image. On the optical path of the charge removing means, a developer removing means for removing the developer remaining on the surface of the image carrier after the transfer, a charge removing means for irradiating the image carrier with light to remove the charge. And a developer scattering prevention member that is provided in contact with the image carrier and that prevents scattering of the developer removed from the surface of the image carrier by the developer removing means. ,
There is provided an image forming apparatus, characterized in that it is colored in a color selected corresponding to the color of the static elimination light of the static elimination unit.

The developer scattering prevention member used in the image forming apparatus of the present invention is colored by containing therein a dye or pigment of a color selected corresponding to the color of the charge eliminating light of the charge eliminating means. Is desirable. Also, the dye or pigment is preferably non-conductive.

[0009]

In the image forming apparatus of the present invention, the toner scattering prevention member colored in a color selected corresponding to the emission color of the charge eliminating lamp is used. Therefore, the static elimination light does not easily pass through the toner scattering prevention member, and even if the toner scattering prevention member is deteriorated due to long-term use or is contaminated by toner or the like, it is irradiated to the photosensitive drum. There is little fluctuation in the amount of lightning. As a result, the surface potential of the photosensitive drum does not fluctuate, and it is possible to always obtain an image of constant image quality.

Further, when the developer scattering prevention member is colored by containing a dye or pigment of a color selected corresponding to the color of the static elimination light of the static elimination means inside, the surface of the photosensitive drum is colored. It is not contaminated by dyes or pigments, and when non-conductive dyes or pigments are used, the surface potential of the photoconductor drum is not leaked and good image quality is obtained. It is possible.

[0011]

Embodiments of the present invention will be described below with reference to the drawings to more specifically describe the present invention. FIG. 1 is a sectional view of an electrophotographic apparatus according to an embodiment of the present invention. Figure 1
The copying machine shown in is constructed as follows. That is, a drum-shaped photosensitive member 103 is provided as an image carrier rotatably in a direction indicated by an arrow a in the center of a copying machine main body 101 (hereinafter referred to as the main body 101). Photoconductor 103
Has a photoconductive layer on its surface. This photoconductor 103
The following devices are fixed around the circumference of the machine along the direction of rotation.

That is, the charging charger 105 that uniformly charges the surface of the photoconductor 103, and this charging charger.
A slit glass 107 for slit exposure of a document image as a light source is provided on the charged photoconductor 103 above the photoconductor 103 on the downstream side in the rotation direction of the photoconductor 103. Further, on the downstream side of the slit glass 107, a developing device 109 for developing a toner by attaching a toner to the electrostatic latent image on the photoconductor 103.
In the developing device 109, a toner 110 mixed with a carrier as a developer is housed.

In the developing device 109, a stirring roller 20 for stirring and frictionally charging the developer by the rotation of the roller 20.
1, and a supply roller 202 for supplying the developer stirred by the stirring roller 201 to the developing roller 203. Further, in the developing device 109, a magnet roller 203, in which S poles and N poles are alternately arranged along the rotation direction of the roller, is rotated in the direction of arrow l in the drawing in a state of approaching the photoconductor 103. It is possible.

At the downstream side of the developing device 109, the carrier recovery device 300, the transfer device 111 and the peeling device 113.
Is provided. As will be described in detail later, the carrier recovery device 300 is a device that magnetically adsorbs the carrier attached to the photoconductor and recovers it in the developing device 109, and the transfer device 111 is a toner formed by the developing device 109. A peeling device 113 is a device that transfers an image onto a copy sheet (hereinafter, referred to as a sheet).
3 is a device for peeling the paper adsorbed on the surface from the surface of the photoconductor 103.

Downstream of the peeling device, among the toners 110 attached to the surface of the photoconductor 103, the toners remaining on the photoconductor 103 after being transferred by the transfer device 111.
A cleaning device 115 for removing 110 is provided. Cleaning device 115 and charging charger 10
A charge eliminating device 117 for lowering the potential of the photoconductor 103 is provided between 5 and 5.

Further, the main body 101 has an original glass 119 on which an original is placed and an optical system 121 which irradiates the original on the original glass 119 with light and guides the reflected light onto the surface of the photosensitive member 103. . The optical system 121 includes a lamp 123 as a light source and mirrors 124, 125, 127, 129, 131, 13 for reflecting light emitted from the light source.
3 and a lens unit 135 for forming an image of reflected light
have.

The lamp 123 and the mirror-124 are configured to be movable under the original glass 119, and in order to keep the optical path length always constant, the mirror-125 and the mirror-127 are half of the lamp 123. It is configured to move at speed. The reflected light from the mirror-133 is configured to pass through the slit glass 107 and be guided to the surface of the photoconductor 103.

Further, a manual feed tray 141 for accommodating sheets is provided in the middle of the right side of the main body 101 in a removable manner, and the main body 1 has a paper tray accommodated in the manual feed tray 141 above the front end of the manual feed tray 141. A pickup roller 143 for pulling out is provided.

On the left side of the main body 101, there is provided a paper discharge tray 171 for discharging copied paper.
Between the manual feed tray 141 and the paper discharge tray 171,
A sheet conveying path, that is, a conveying path 142 is formed, and the conveying path 142 is shown by a dotted line in FIG.

Two pairs of rollers, a first pair and a second pair, are attached to the main body 101 upstream of the conveying path 142. The first roller pair is adjacent to the manual feed tray 141 and is composed of two rollers, a paper feed roller 145 and a separation roller 147. The paper feed roller 145 is a roller that can rotate in the direction of the arrow b in the figure, and is a roller for sending the paper pulled out by the pickup roller 143 to the second roller pair by the rotation of the roller. is there.

The separating roller 147 is provided below the paper feeding roller 145 so as to be in contact therewith, and when two or more sheets are sent from the pickup roller 143, the paper feeding roller 147 is provided. The extra paper is pulled back to the manual feed tray 141 by rotating in the opposite direction of the rotation direction of the la 145. Separating roller 147
When the number of sheets sent from the pickup roller 143 is one, the sheet feeding roller 145 is rotated by the rotation. The second roller pair is a resist roller 149 composed of an upper roller and a lower roller. Registrar
The roller 149 aligns the paper by hitting the leading edge of the paper sent from the paper feed roller 145, and then the paper is placed on the photoconductor 103 between the photoconductor 103 and the transfer device 111. Send it so that it overlaps with the toner image.

The transfer device 1 is provided in the middle of the transport path 142.
11 and a peeling device 113 are arranged, and a belt-shaped belt for transporting paper, that is, a transport belt 15 is provided at the tip thereof.
1 is provided. Further, on the downstream side of the transport path 142, heating and pressurizing the toner 110, the toner 11 is discharged.
A fixing device 153 for fixing 0 on paper is installed. The fixing device 153 includes a heat roller 157 and a pressure roller 1 which are rotatable in directions c and d in the drawing.
Have 59. The heat roller 157 has a built-in heat lamp 155, which is a heating body, and is partially pressure-bonded to the pressure roller 159. The surface of the heat roller 157 is made of a metal member having good thermal conductivity, and the surface of the pressure roller 159 is made of an elastic rubber member so that it can be easily pressure-bonded to the heat roller 157. There is.

Further, downstream of the conveying path 142, a paper discharge roller for discharging the paper on which the copying machine is mounted onto a paper discharge tray 171.
La 161 is provided. The copying process by the copying machine described above is as follows.

First, the surface of the photosensitive member 103 is uniformly charged by the corona discharge of the charging charger 105. Next, the lamp 123 in the optical system 121 scans under the original glass 119 on which the original is placed, and the original is irradiated with light. When scanning is performed by the lamp 123, the lamp 12
The light emitted from 3 is reflected, and the reflected light is guided to the lens unit 135. The reflected light is inverted by the lens unit 135 and is exposed on the charged photoconductor 103 through the slit glass 107. When the light is exposed,
The charge on the surface of the photoconductor 103 is lost and an electrostatic latent image is formed.

In the developing device 109, the stirring roller 201
The toner 110 and the carrier that are agitated and friction-charged are sent to the magnet roller 203 by the supply roller 202. Tona-1 sent to the magnet roller 203
10 and the carrier are S in the magnet roller 203.
A magnetic brush is formed by the magnetic force lines formed between the poles and the N poles. The carrier is always magnetically attracted to the magnet roller 203, and the toner 110 is electrically attracted to the carrier.

Then, when the magnet roller 203 and the photoconductor 103 rotate and the magnetic brush and the electrostatic latent image on the photoconductor 103 come close to each other, the toner becomes stronger due to the stronger electrostatic attraction of the electrostatic latent image. 110 separates from the carrier and adheres to the electrostatic latent image. The toner 110 attached to the electrostatic latent image forms a toner image. During development, the developing bias is applied to the magnet roller 203 and the photoconductor 10 by a voltage device (not shown).
The unnecessary toner 110 is prevented from adhering to the photoconductor 103 over the period of 3.

On the other hand, the paper stored in the paper feed cassette 141 is pulled out by the pickup roller 143,
Among the pulled-out sheets, only one sheet is sent to the registration roller 149 by the rotation of the sheet feeding roller 145 and the separation roller 147. The registration roller 149 aligns the leading edge of the sheet and then sends the sheet between the photoconductor 103 and the transfer device 111 to superimpose it on the electrostatic latent image on the photoconductor 103. On the back side of this fed paper,
The toner image is transferred onto the paper by the operation of the transfer device 111. The sheet on which the toner image is formed in this manner is peeled from the surface of the photoconductor 103 by the peeling device 113, is conveyed on the conveyor belt 151, and reaches the fixing device 153.

In the fixing device 153, the heat roller 15 heated by a heat lamp 155 incorporated in advance is used.
7 and the pressure roller 159 rotate in their respective viewpoint directions while partially pressure-bonding. Heat roller 157 and pressure roller
When the roller 159 is rotated, the toner image is fixed onto the paper by passing the paper so that the toner image is on the heater-roller side through the pressure-bonded portions of these two rollers. That is, the heat of the heat roller 157 melts the toner 110, the pressure of the pressure roller 159 enhances the heat conduction efficiency, and the toner is soaked between the fibers of the paper.

The sheet on which the copied image is formed through the above process is discharged to the sheet discharge tray 171 through the sheet discharge roller 161. Next, with reference to FIG. 2, the positional relationship around the photosensitive drum including the toner-scattering prevention member, which is a feature of the present invention, will be described.

As described above, the charging charger 105 for uniformly charging the surface of the photoconductor 103 and the untransferred toner 110 remaining on the photoconductor 103 after the transfer are provided around the photoconductor drum 103. Kakitore Cleaning Blade 1
15, a static elimination lamp 117 for lowering the potential of the photoconductor 103, and a toner scattering prevention member 118 for preventing the toner scraped by the cleaning blade 115 from scattering on the static elimination lamp 117. It is arranged. In this embodiment, the toner scattering prevention member 118 is colored black.

As shown in more detail in FIG. 3, the tip of the toner scattering prevention member 118 is in contact with the surface of the photosensitive drum 103, is located in the optical path of the static elimination light from the static elimination lamp 117, and is irradiated with the static elimination light. It accounts for a certain proportion in the width. Therefore, the charge removal light is applied to the photoconductor drum 103 in a form of passing through the tip of the toner scattering prevention member 118.

FIG. 4 is a characteristic diagram showing changes in the light quantity of the static elimination light and the surface potential after passing through the toner scattering prevention member depending on the number of copies of the copying machine. From FIG. 4, when a toner scattering prevention member made of a conventional transparent urethane sheet is used, the quantity of transmitted static elimination light decreases and the surface potential rises as the number of copies increases, but the urethane sheet colored black. In the case of the present embodiment using the toner scattering prevention member consisting of, the light quantity and surface potential of the transmitted static elimination light does not change even if the number of copies increases. In the conventional toner scattering prevention member made of a transparent urethane sheet, as the number of copies increases, the quantity of transmitted static elimination light decreases due to stains and deterioration of material due to toner, but like the present embodiment. This is because, if the toner scattering prevention member is colored black, the static elimination light does not pass through the toner scattering prevention member, so that the light amount does not change from the beginning.

In this way, the image forming apparatus according to this embodiment can always form a good image. Next, the inventor changed various kinds of the photoconductor drum, the emission color of the static elimination lamp, the material of the toner scattering prevention member, and the color of the toner scattering prevention member to actually change the life of 300,000 copies. Conducted a test to increase the surface potential of the photosensitive drum,
We examined the problems of images and photoconductor drums. The results are shown in Table 1 below.

[0034]

[Table 1]

From Table 1 above, the test No. in which the toner scattering prevention member is translucent In No. 1, the surface potential fluctuates and the exposure fluctuates, which is not preferable. Also,
The color of the toner scattering prevention member does not have to be any color, and it is necessary to select the color according to the emission color of the static elimination lamp determined by the type of the photosensitive drum. This is because the amount of light transmitted through the toner scattering prevention member changes depending on the emission color of the static elimination lamp, even if the toner scattering prevention member has the same color. For example, when an arsenic selenium drum is used as the photosensitive drum and a green light lamp is used as the static elimination lamp, the test No. As shown in FIGS. 5 and 14, the color of the toner scattering prevention member is preferably red, black (non-carbon) or a color close to these. Similarly, when an OPC photoconductor is used as the photoconductor drum and a white light lamp is used as the static elimination lamp, the test No. As shown in FIG. 6, the color of the toner scattering prevention member is preferably black (non-carbon) or a color close thereto. Furthermore, when an amorphous silicon (a-Si) photoconductor is used as the photoconductor drum and a red light lamp is used as the static elimination lamp, a test N
o. As shown in Nos. 7 and 13, the color of the toner scattering prevention member is preferably blue, black (non-carbon) or a color close thereto.

The above test No. 5,6,7,13,1
Each of the toner scattering prevention members used in No. 4 was colored in such a manner that a dye and a pigment were contained inside the urethane sheet.
However, when carbon black was used (Test No.
2, 3, 4), carbon black is conductive,
Since the toner scattering prevention member is disposed in contact with the photoconductor drum, the potential leaks, causing a problem in the image (particularly in the case of a halftone). Further, in the case of the toner scattering prevention member (Test Nos. 8, 9, and 10) colored by coating the surface of the urethane sheet with a dye, the dye contaminates the photosensitive drum, and an image defect also occurs. did.

Regarding the material of the toner scattering prevention member, when Mylar sheet (Myra is a registered trademark of DuPont) is used (Test Nos. 11, 12, and 13), the photosensitive drum is an arsenic selenium drum. In the case of test No. 11),
In both cases of OPC and OPC (Test No. 12), the photoconductor drum was scratched, but the photoconductor drum was aS
In the case of the i-drum (Test No. 13), the hardness of the a-Si drum was considerably higher than that of arsenic selenium and OPC, so that the drum was not scratched.

From the above results, the most preferable toner scattering prevention member used in the image forming apparatus of the present invention is
Considering the friction with the photoconductor drum, soft material that does not damage the photoconductor drum, or dyes or pigments that are applied in a way that does not contaminate the photoconductor drum, such as dyes or pigments inside Those included, those which are non-conductive, and those which are colored corresponding to the static elimination light of the static elimination lamp matched with the spectral sensitivity of the photosensitive drum.

[0039]

As described above, according to the present invention,
As the toner scattering prevention member, a member colored in a color selected corresponding to the emission color of the static elimination lamp is used,
Even if the toner scattering prevention member is deteriorated or contaminated due to an increase in the number of copies, the surface potential of the photosensitive drum does not change, and it is possible to always obtain a constant image.

[Brief description of drawings]

FIG. 1 is a diagram showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an arrangement around a photosensitive drum of an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a toner of an image forming apparatus according to an embodiment of the present invention.
The figure which shows the position of a scattering prevention member schematically.

FIG. 4 is a characteristic diagram showing changes in the amount of static elimination light and the surface potential after passing through the toner scattering prevention member depending on the number of copies made by a copying machine.

[Explanation of symbols]

 Reference numeral 101 ... Copier main body 103 ... Photoconductor 105 ... Charging charger 107 ... Slit glass 109 ... Developing device 110 ... Toner 110 111 ... Transfer device 115 ... Cleaning blade 117 ... Static elimination lamp 118 ... Toner scattering prevention Member 203 ... Developing roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03G 21/00 342

Claims (3)

[Claims] 1. An image carrier, means for forming an electrostatic latent image on the image carrier, and developing means for supplying a developer to the image carrier to develop the latent image on the image carrier. , Transfer means for transferring the developed developer image to a transfer material, developer removing means for removing the developer remaining on the surface of the image carrier after transfer, and irradiating the image carrier with light to eliminate the charge. A charge removing unit and a developer scattering prevention member which is provided on the optical path of the charge removing unit in contact with the image carrier and prevents scattering of the developer removed from the image carrier surface by the developer removing unit. The image forming apparatus, wherein the developer scattering prevention member is colored in a color selected in accordance with the color of the static elimination light of the static elimination unit. 2. The image forming apparatus according to claim 1, wherein the developer scattering prevention member is colored by containing a dye or pigment of the selected color inside. 3. The image forming apparatus according to claim 1, wherein the dye or pigment of the selected color and the developer scattering prevention member are non-conductive.