JP2002099189A - Discharge product removing device and image forming device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove discharge products sticking on an image carrier by a discharge product removing device of small-sized, simple constitution as to an image forming device which obtains a recording image by transferring a toner image formed on the surface of the image carrier to a transfer material. SOLUTION: The discharge product removing device 19 is constituted by holding a powdery highly-water-absorptive substance 30 in pores 31 of a porous member 29 and pressed against the surface of the image carrier to take the discharge products in the highly-water-absorptive substance 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge product removing apparatus and an image forming apparatus having the discharge product removing apparatus.

[0002]

2. Description of the Related Art An image forming apparatus, such as a copying machine, a printer, a facsimile, or a multifunction machine having at least two of these functions, has an image carrier having a surface on which a toner image is formed. It is configured to form a recorded image by transferring an image to a final transfer material. Around the image carrier, there is provided a device which causes a discharge during operation. For example, when the image carrier is configured as a photoconductor on which an electrostatic latent image is formed, a charging device that charges the surface of the image carrier is an example of a device that involves a discharge during operation.

When a discharge product generated by the discharge of such an apparatus adheres to the surface of the image carrier, the image carrier is deteriorated, and an abnormal image may be formed on the surface of the image carrier. For example, nitrogen oxides are generated by the discharge and combine with substances in the air to generate nitric acid compounds, which adhere to the surface of the image carrier as discharge products. When such a discharge product absorbs moisture in the air, the resistance of the surface of the image carrier decreases, whereby an abnormal image is generated on the image carrier. For example, image blur occurs in which the density of the toner image is extremely low.

In order to solve such a problem, various configurations have conventionally been proposed. For example, there has been proposed a discharge product removing device having a water application member for applying water to the surface of an image carrier and a water removing member for removing water from the surface of the image carrier (Japanese Patent Application Laid-Open No. 60-49352). reference). This discharge product removal device utilizes the property that the discharge product generated on the surface of the image carrier is soluble in water, and has an advantage that the discharge product can be removed relatively effectively.

However, since the discharge product removing device according to the above proposal has a water application member and a water removing member, a large space is required for disposing these members around the image carrier. And the size of the image forming apparatus may be increased.

The surface of the image carrier is generally hydrophobic, but when water is applied to the surface of the image carrier, the water is turned into sparse water droplets due to the hydrophobicity of the surface of the image carrier. It adheres to the surface of the image carrier. Therefore, when water is applied to the surface of the image carrier, even if the discharge product is dissolved in the water, the aqueous solution containing the discharge product becomes water droplets and adheres sparsely to the surface of the image carrier. Such water droplets are wiped off, but at the time of the wiping, since the water droplets on the surface of the image carrier are sparse, the surface of the image carrier to which the water droplets are attached and the image carrier without the water droplets are removed. There is a possibility that the effect of removing the discharge products is different between the body surface portion and the characteristics of the surface of the image carrier after wiping are not uniform.

[0007]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a discharge product removing apparatus which eliminates the above-mentioned conventional disadvantages.

A second object of the present invention is to provide an image forming apparatus having a discharge product removing apparatus which eliminates the above-mentioned conventional disadvantages.

[0009]

In order to achieve the first object, the present invention provides a discharge product characterized in that a powdery superabsorbent substance is held in pores of a porous member. A removal device is proposed (claim 1).

[0010] At this time, it is advantageous that the superabsorbent material is held in the pores in a state of being swollen with water (claim 2).

Further, in the discharge product removing apparatus according to claim 1 or 2, it is advantageous that the porous member is made of an elastic material having hydrophilicity (claim 3).

Further, in the discharge product removing apparatus according to any one of claims 1 to 3, the porous member is fixed concentrically outside a core shaft, and the porous member and the core shaft are rotatable. It is advantageous if it is formed in a simple roller shape.

According to another aspect of the present invention, there is provided an image carrier having a surface supported to move and a toner image formed on the surface. An image forming apparatus comprising: the discharge product removing device according to any one of the above, wherein the discharge product removing device directly contacts at least the surface of the image bearing member with at least the water-swelled superabsorbent substance. Is proposed (claim 5).

In this case, it is advantageous that the discharge product removing device is configured to abut on the surface of the image carrier while rotating following the movement of the surface of the image carrier. ).

The image forming apparatus according to claim 5 or 6, wherein a charging device for charging a surface of the image carrier is provided.
A latent image forming means for forming an electrostatic latent image on the surface of the image carrier charged by the charging device, a developing device for visualizing the electrostatic latent image as a toner image, and applying the toner image to a transfer material Transfer device for transferring, the discharge product removal device,
In the moving direction of the surface of the image carrier, it is advantageous that the image carrier is configured to be in contact with a surface portion of the image carrier upstream of the charging device and downstream of a transfer position of the toner image by the transfer device. (Claim 7).

Further, in the image forming apparatus according to any one of claims 5 to 7, the discharge product removing device is arranged such that the discharge product removing device comes into contact with or separates from the surface of the image carrier. It is advantageous to provide a contact / separation means for actuating (claim 8).

Further, in the image forming apparatus according to the present invention, a sensor for detecting a state of adhesion of the discharge product to the surface of the image carrier, and an amount of the discharge product attached to the surface of the image carrier is a predetermined amount. It is advantageous to provide control means for controlling the contact / separation means so that the discharge product removing device comes into contact with the surface of the image carrier when it is detected that the discharge has occurred (claim 9).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic partial sectional view showing an example of the image forming apparatus. The image forming apparatus shown here has an image carrier 1 configured as a drum-shaped photoconductor, and the image carrier 1 is driven to rotate clockwise in FIG. 1 with the start of the image forming operation. . At this time, the surface of the image bearing member is irradiated with light from the discharge lamp 2, and the surface of the image bearing member undergoes a charge removing operation, thereby initializing the surface potential. On the other hand, a charging voltage is applied to a charging wire 4 of a charging charger 3 which is an example of a charging device, and a discharge generated by the charging voltage causes
The initialized image carrier surface has a predetermined polarity, for example, -9.
It is uniformly charged to 00V.

Instead of the drum-shaped photoreceptor, an image carrier made of a belt-shaped photoreceptor wound around a plurality of rollers and driven to run, or an image carrier made of a dielectric material can be used. In either case, the image carrier is supported so that its surface moves. Further, instead of the charging charger, a charging device including a charging roller, a charging blade, a charging brush, or the like can be used.

On the surface of the image carrier charged as described above, a laser writing device 5 as an example of a latent image forming means is provided.
Is irradiated with the laser light L modulated by light, and an electrostatic latent image corresponding to an image signal is formed on the surface of the image carrier. The potential of the surface of the image carrier irradiated with the laser light is, for example, -150 V, which is an electrostatic latent image, that is, an image portion, and the potential of the surface of the image carrier not irradiated with the laser light is maintained at approximately -900 V. This is the background.

When the electrostatic latent image passes through the developing device 6, it is visualized as a toner image. The developing device 6 exemplified here includes a developing case 7 containing a powdery two-component developer D having a toner and a carrier, a developing roller 8 disposed to face the image carrier 1 and rotating, While stirring the developer D. The toner has a predetermined polarity by friction with the carrier,
In the example shown in the figure, the developer D that is charged to a negative polarity and contains the toner is conveyed while being carried on the peripheral surface of the developing roller 8 by magnetic force, and is conveyed to a developing area between the developing roller 8 and the image carrier 1. It is. At this time, a predetermined developing bias (for example, a voltage of −600 V) is applied to the developing roller 8.
As a result, the toner in the developer carried to the developing area is electrostatically transferred to the electrostatic latent image formed on the image carrier 1, that is, the image portion, and the electrostatic latent image is converted into a visible image as a toner image. Be transformed into Thus, a toner image is formed on the surface of the image carrier 1. A developing device using a powdery one-component developer containing no carrier or a liquid developer can also be employed.

A transfer roller 11, which is an example of a transfer device for transferring a toner image formed on the surface of the image carrier to a transfer material, is opposed to the image carrier 1. The transfer roller 11 is provided on the surface of the image carrier. While being rotated counterclockwise in FIG. The transfer roller 11 and the image carrier 1
Is supplied from a paper supply unit (not shown), and the arrow B
The transfer material P sent in the direction passes. At this time, a transfer voltage having a polarity opposite to the charge polarity of the toner of the toner image on the image carrier, that is, a positive polarity in this example, is applied to the transfer roller 11, and a current of, for example, 10 μA is supplied. As a result, the toner image is electrostatically transferred onto the transfer material P sent at a timing that can be matched with the toner image formed on the surface of the image carrier. The transfer material P that has passed between the transfer roller 11 and the image carrier 1 is separated from the image carrier 1 by a separation claw 13 and passes through a fixing device (not shown).
The transferred toner image is fixed on the transfer material by the action of heat and pressure. Next, the transfer material P is discharged outside the apparatus. As the transfer material P, for example, paper, a resin sheet or a resin film is used. Further, in place of the transfer roller 11, a transfer device such as a transfer charger, a transfer brush or a transfer blade can be used.

As described above, the toner adhering to the surface of the image carrier that has passed the transfer position where the transfer of the toner image is performed is removed by the cleaning device 14. The cleaning device 14 illustrated here is the cleaning case 1
6, a cleaning blade 17 whose base end is fixed to the case 16 and whose distal end is made of an elastic body pressed against the surface of the image carrier, and a toner discharge screw 18. The upper toner is scraped off. The removed toner is discharged outside the cleaning case by the rotating toner discharge screw 18. In this way, the untransferred toner remaining on the surface of the image carrier without being transferred to the transfer material is removed from the surface of the image carrier. The cleaning blade 17 is an example of a cleaning member that contacts the surface of the image carrier and removes toner attached to the surface.

When images are successively formed on a plurality of transfer materials, the above-described operation is repeated, and the transfer roller 11 and the image carrier 1 are spaced at a certain distance from the transfer material P. And the toner image is transferred onto the next transfer material sent between them. After transferring the toner image to a predetermined number of transfer materials,
The image carrier 1 stops.

As described above, the image forming apparatus of this embodiment has an image carrier 1 supported so that its surface moves, a charging device for charging the surface of the image carrier, and a charging device for charging the surface of the image carrier. Latent image forming means for forming an electrostatic latent image on the surface of the image carrier, a developing device for visualizing the electrostatic latent image as a toner image, and a transfer device for transferring the toner image to a transfer material. And a cleaning device that removes toner adhering to the surface of the image carrier that has passed the transfer position where the transfer of the toner image is performed. In the illustrated example, the latent image forming unit is configured to expose the charged surface of the image carrier to form an electrostatic latent image on the surface. Forming means can also be employed. When the developing device is configured to remove transfer residual toner attached to the surface of the image carrier, the cleaning device can be omitted. Also, FIG.
Reference numeral 9 denotes a discharge product removing device, which will be described later in detail.

In the charging charger 3 shown in FIG. 1, a predetermined charging voltage is applied to the charging wire 4, and the surface of the image carrier is charged by the discharge at this time. At the time of the discharge, nitrogen oxides (NOx) are generated, which are combined with substances in the air to generate a nitric acid compound, which adheres to the surface of the image carrier as a discharge product. When the charging device is formed of a charging charger, when the image forming operation is completed and the image carrier 1 stops, a large amount of discharge products adhere to the surface of the image carrier facing the charging charger. Charging roller as charging device,
Even when a charging brush or a charging blade is used, the generation of nitrogen oxides is smaller than in the case of the charging charger, and nitrogen oxides are generated in the same manner and adhere to the surface of the image carrier as discharge products. . Even when the transfer voltage is applied to the transfer roller 11, discharge products may adhere to the image carrier even when the transfer roller 11 is applied with the transfer voltage. The same applies when a transfer device other than the transfer roller is used.

Assuming that the discharge product composed of the nitric acid compound adhered to the surface of the image bearing member as described above is left undisturbed, the discharge product is water-soluble, so that it absorbs the moisture in the atmosphere and absorbs the water. And dissociates into ions. As described above, the discharge products on the image carrier absorb water, so that the surface potential of the image carrier decreases. For this reason, when the amount of the discharge product on the image carrier increases, the predetermined image formation is not performed, and the toner image after development is blurred and the image quality is significantly deteriorated.

If the cleaning blade 17 shown in FIG. 1 is strongly pressed against the surface of the image carrier and the discharge products adhered to the surface of the image carrier are scraped off by the cleaning blade 17, the image blur caused by the discharge products is reduced. Although it is possible to prevent the occurrence of an abnormal image such as that described above, if the cleaning member is pressed too strongly against the surface of the image carrier, a large amount of the photosensitive layer on the surface of the image carrier is scraped off, shortening the life of the image carrier. Can be

Therefore, the image forming apparatus of the present embodiment is provided with a discharge product removing device 19 for removing the discharge products adhered to the surface of the image carrier, whereby an abnormal image caused by the discharge products is formed. The configuration is such that defects formed on the surface of the carrier can be prevented.

FIG. 2 is a sectional view taken along the line II-II of FIG.
FIG. 2 is an explanatory diagram schematically showing an enlarged discharge product removing device 19 shown in FIG. 1. As shown in these figures, the discharge product removing device 19 of the present example has a core shaft 28 made of a highly rigid material such as metal or hard resin, and a cylindrical shape fixed concentrically outside the core shaft 28. Porous member 29 and the superabsorbent substance 30 held in the holes 31 of the porous member 29
And the porous member 29 and the core shaft 28 are formed in a rotatable roller shape. The discharge product removing device 19 applies a powdery superabsorbent substance around the porous member 29 fixed to the core shaft 28 so as to cover the porous member 29, and applies the superabsorbent substance to the porous member 29. Many holes 31
It is constituted by filling inside and swelling the superabsorbent substance with water. At this time, it is desirable that the porous member 29 also contains water.

More specifically, the hole 31 of the porous member 29 has a diameter of, for example, about 0.5 mm, and a powder having a particle diameter of, for example, about 0.1 μm to 0.5 μm is contained in the hole 31. The body-like super absorbent material 30 is held in a state of being swollen with water. In the example shown in FIG. 3, the superabsorbent material 30 is held only in the large number of holes 31 exposed on the surface of the porous member 29. 30 may be filled. The superabsorbent material may or may not adhere to the outer peripheral surface portion 32 other than the holes 31 exposed on the surface of the porous member 29.

Each end of the core shaft 28 in the longitudinal direction is rotatably supported, for example, directly on the side plate of the main body of the image forming apparatus or via another member.

As described above, the discharge product removing device 19
Are the holes 31 of the porous member 29 in which a number of holes 31 are formed.
When the discharge product removing device is used, the super absorbent material 30 is held in the holes 31 in a state of being swollen with water. Then, as shown in FIG. 2, the discharge product removing device 19 abuts at least over the entire width of the image forming area of the image carrier 1, that is, the area of the surface of the image carrier where the toner image is formed. At this time, when the superabsorbent material is also retained on the outer peripheral surface portion 32 of the porous member 29, only the superabsorbent material directly contacts the surface of the image carrier, and the porous member 29 becomes highly absorbent. When the superabsorbent material 30 is held only in the holes 31 on the outer peripheral surface and the superabsorbent material is not retained in the outer peripheral surface portion 32, Both the superabsorbent material 30 and the outer peripheral surface portion 32 of the porous member 29 come into direct contact with the surface of the image carrier. As described above, in the discharge product removing device 19, at least the super absorbent material swollen with water comes into direct contact with the surface of the image carrier.

The porous member 29 may be hydrophobic or hydrophilic, and may be formed of a rigid body or an elastic body. In the image forming apparatus of this embodiment, The porous member 29 is made of an elastic material having hydrophilicity.

The discharge product removing device 19 in contact with the surface of the image carrier is driven to rotate around the central axis of the core shaft 28 by the rotation of the image carrier 1 as described above.
The discharge product removing device 19 abuts on the image carrier surface while rotating following the movement of the image carrier surface. At this time, since the porous member 29 of the present example has elasticity, the porous member 29 is moved in the circumferential direction of the image carrier by pressing the discharge product removing device 19 against the surface of the image carrier. It is pressed against the surface of the image carrier with a nip width N (FIG. 1). Instead of causing the discharge product removing device 19 to follow and rotate with the rotation of the image carrier 1, the discharge product removing device 19 may be configured to be rotationally driven by a driving device (not shown).

The superabsorbent material 30 is made of, for example, polyacrylic acid, polymaleic acid, polymethacrylic acid, polyacrylamide, polyacrylic acid soda having a crosslinked structure, a derivative thereof, or a copolymer thereof. . Alternatively, polyalkyl oxides such as polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl butyral, polyacrylamide, polypropylene glycol, glue, gelatin, casein, albumin, alginic acid, sodium alginate, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl ether, polyvinyl Methylcellulose, polyethylene glycol, glucose, xylose, sucrose, maltose, arabinose, α-cyclodextrin, starch, or a copolymer, graft polymer, or crosslinked product thereof can constitute the superabsorbent substance 30. However, the present invention is not limited to this.

The porous member 29 is made of, for example, urethane rubber, silicone rubber, ethylene propylene rubber, butadiene rubber, styrene rubber, chloroprene rubber, butylene rubber, elastomer, sponge, polyethylene, polystyrene, polypropylene, polyurethane, vinyl chloride, epoxy , A foam such as a resin such as phenol, urea or vinylon, or various thermoplastic resins, or a foam obtained by subjecting them to a hydrophilic treatment, but is not limited to these materials.

A discharge product composed of a nitric acid compound adhered to the surface of the image carrier by the discharge reaches the inlet side of the pressure contact portion between the image carrier and the discharge product removing device 19 as the image carrier 1 rotates. And the discharge product, from the image carrier surface,
It transfers to the superabsorbent substance 30 swollen with water and is retained in the superabsorbent substance 30. The superabsorbent material 30 absorbs a large amount of water and swells, but does not dissolve in water, and discharges or inhales water according to the pressing force on the surface of the image carrier or the humidity of the atmosphere. Do so-called breathing, dissolve the water-soluble discharge products with the water you exhale,
It functions to absorb the aqueous solution of the discharge product. The discharge product is taken into the superabsorbent material 30 and held.

When the discharge product removing device 19 makes one rotation,
Some of the discharge products held as ions in the superabsorbent material 30 ooze out again with water on the surface of the image bearing member. However, since the nitric acid compound has a very high solubility in water, the discharge products are mixed with water again. Even if it goes out to the surface of the image carrier, it is taken into the superabsorbent substance 30 again together with the discharge products newly attached to the surface of the image carrier, and is held. In this way, the discharge products are substantially not adhered to the surface of the image carrier having passed through the discharge product removing device 19 or the amount thereof is extremely small. It is possible to prevent a problem that an image blur caused by an object is generated, and it is possible to enhance the image quality of the toner image formed on the transfer material.

In the discharge product removing device 19 of this embodiment, since the porous member 29 is made of an elastic material, the porous member 29 has an image with a large nip width N directly or through the superabsorbent material 30. It is pressed against the surface of the carrier, thereby increasing the effect of removing discharge products. Moreover, since the pressure per unit area between the porous member 29 and the surface of the image carrier can be reduced, it is possible to prevent a problem that the surface of the image carrier is damaged.

In the discharge product removing apparatus 19 of this embodiment, since the porous member 29 is hydrophilic, the same hydrophilic superabsorbent material 30 and the porous member 29 are easily adhered to each other. The water-absorbing substance 30 is inserted into the hole 3 of the porous member 29.
The function of holding at 1 is enhanced. This makes it possible to enhance the retention of the superabsorbent material 30 with respect to the porous member 29.

Further, the surface of the image carrier made of a photoreceptor is hydrophobic, and the porous member 29 and the superabsorbent material 30 pressed against it are hydrophilic, so that the adhesion between them is weak. It is difficult for the superabsorbent substance 30 to migrate to the surface of the image carrier, and the superabsorbent substance 30 is transferred to the porous member 2 for a long period of time.
9 can be held. Moreover, even if a slight amount of the superabsorbent substance 30 adheres to the surface of the image carrier, the adhesion between the superabsorbent substance 30 and the surface of the image carrier is weak.
The cleaning member of the cleaning device 14, for example, FIG.
By using the cleaning blade 17 shown in (1), the superabsorbent substance adhering to the surface of the image carrier can be removed with a weak force that does not damage the surface.

Further, since the superabsorbent substance 30 is a powder, the superabsorbent substance 30 can be uniformly dispersed and held in the pores 31 of the porous member 29, and thereafter, the superabsorbent substance is superabsorbed with water. Since the substance 30 may be swollen, the discharge product removing device 19 can be easily manufactured.

Further, since the discharge product removing device 19 is brought into contact with the surface of the image carrier by pressurizing and rotating, the application of a large stress to the image carrier 1 can be prevented. In particular, a large load is not applied to the image carrier in the circumferential direction, and the image carrier 1 is not greatly distorted in the circumferential direction, so that the durability can be improved.

As described above, since the discharge products can be removed from the surface of the image carrier by providing the discharge product removing device 19, the cleaning blade 17 and the like can be used.
Even if a large amount of the photosensitive layer on the surface of the image carrier is not removed, it is possible to prevent a problem that image blur occurs. For this reason, the durability of the image carrier can be enhanced, and its life can be extended.

Further, since the discharge product removing device 19 is formed as an integral member, the discharge product removing device 19 is compared with a conventional discharge product removing device having a water application member and a water removing member. The space for disposing the device 19 around the image carrier 1 can be reduced, and the size of the image forming apparatus can be reduced.

If the surface of the image carrier made of a photoreceptor is hydrophilic, it adsorbs a large amount of moisture in the atmosphere, and the electric resistance of the surface is reduced, thereby forming a predetermined electrostatic latent image. Can no longer hold the charge needed for
The photoreceptor surface needs to be hydrophobic. The discharge product removing device 19 supplies water to the discharge products attached to the surface of the image carrier almost at the same time as supplying water to the discharge products, so that the discharge products are sucked into the superabsorbent material 30. As in the conventional discharge product removing apparatus in which water is applied to the body surface and then the water is wiped off with a water removing member, a problem that the characteristics of the surface of the image bearing member after the discharge products are not uniform can be prevented.

Since the illustrated discharge product removing device 19 has the core shaft 28, the discharge product removing device 19 can be rotated reliably and accurately. It is also possible to configure a product removal device and rotate the discharge product removal device while making contact with the surface of the image carrier.

Further, when the discharge product removing device 19 formed as an integral member is formed in a roller shape and is rotated, the efficiency of removing the discharge products on the surface of the image carrier is improved. Although the discharge product removing device can be made compact, the discharge product removing device can be formed in other forms. For example, as shown in FIG. 4, the porous member 29 is formed in a cubic shape, and at least a plurality of holes of the surface 33 of the porous member 29 facing the surface of the image carrier hold the superabsorbent material. To image carrier 1
It can also be configured to be pressed against the surface of. At this time, the porous member 29 is fixed to a support member 34 made of a metal plate, a hard resin plate, or the like to hold the porous member 29, to enhance its stability, and to make the porous member 29 uniform on the surface of the image carrier. It can also be configured to be pressed against.

The position at which the discharge product removing device 19 is brought into contact with the surface of the image carrier can be set as appropriate. However, as shown in FIG. 1, the direction of movement of the surface of the image carrier is upstream of the charging device. The discharge product removing device 19 is provided on the surface of the image carrier downstream of the transfer position of the toner image by the transfer device.
, And especially as shown in FIG.
When the discharge product removing device 19 is brought into contact with the surface of the image carrier downstream of the image carrier 4, the surface of the image carrier immediately after the discharge product is removed by the discharge product removing device 19 can be charged. In addition, it is possible to more reliably prevent the problem that the potential of the surface of the image carrier after charging is insufficient.
Since the surface of the image carrier immediately after removing the discharge product to the extent that image blur does not occur is charged by the charger 3 or another type of charging device, the surface potential of the charged image carrier becomes uniform, In addition, a predetermined potential required for forming an electrostatic latent image can be secured, whereby a high-quality image can be formed.

The discharge product removing device 19 is always
The discharge product removing device 19 may be brought into contact with the surface of the image carrier, but in this case, the wear of the discharge product removing device 19 is promoted and its life may be shortened. It is preferable to provide contact / separation means for operating the discharge product removing device 19 so that the contact member comes into contact with or separates from the surface of the image carrier. A specific example of the contact / separation means will be described later. By the operation of the contact / separation means, the discharge product removing device 19 is brought into contact with or separated from the surface of the image carrier, and the load applied to the discharge product removing device 19 is reduced. Alleviate this and achieve a longer life.

For example, the discharge product removing device 19 periodically.
Is brought into contact with the surface of the image carrier to remove discharge products attached to the surface of the image carrier. Specifically, for each image forming operation, the discharge product removing device 19 is brought into contact with the surface of the image carrier once to remove the discharge products. In this case, at the time of image formation, the discharge product removal device 19 is brought into contact with the surface of the image carrier, and the surface of the image carrier immediately after removal of the discharge product is charged, exposed,
It is preferable that development be performed to prevent image blurring, and that the discharge product removing device 19 be separated from the surface of the image carrier before the start of each image forming operation or after the end thereof.

Also, every time the image forming operation is completed a predetermined number of times, or during non-image formation, for example, when the image forming apparatus is warmed up, the discharge product removing device 19 is brought into contact with the surface of the image carrier to generate discharge. Objects can also be removed. In any case, it is possible to rotate the image carrier 1 at least once while keeping the discharge product removing device 19 in contact with the surface of the image carrier, and remove the discharge products over the entire circumference. preferable.

Alternatively, as shown in FIG. 1, with respect to the moving direction of the surface of the image carrier 1, the surface of the image carrier downstream of the charging charger 3, which is an example of the charging device, and upstream of the developing device 6. A sensor 35 for detecting the surface potential of the image carrier 1 is provided at a position facing the portion, and by detecting the potential of the surface of the image carrier after charging by the charging device, the discharge product on the surface of the image carrier is detected. The state of adhesion may be detected, and the discharge product removing device 19 may be brought into contact with the surface of the image carrier according to the detection result. If the amount of the discharge product adhered to the surface of the image carrier increases, the surface potential after charging decreases, and the potential of the discharge product on the surface of the image carrier is detected by detecting the potential with the sensor 35. The amount of adhesion can be known.

As described above, the sensor 35 for detecting the state of adhesion of the discharge products to the surface of the image carrier is provided, and it is detected that the amount of the discharge products adhered to the surface of the image carrier has reached a predetermined amount. At this time, a control means (see FIG. 5) for controlling the above-mentioned contact / separation means is provided so that the discharge product removing device 19 comes into contact with the surface of the image carrier. According to this configuration, when the discharge products are not attached to the surface of the image carrier, or when the amount of the discharge products does not adversely affect the image quality, the discharge product removal device 19 is connected to the image carrier 1. The discharge product removing device 19 is brought into contact with the surface of the image carrier when the amount of the discharge products adhered to the surface of the image carrier has reached a level that adversely affects the image quality, or immediately before. As a result, the discharge products can be removed from the surface of the image carrier, so that the time during which the discharge product removal device 19 contacts the surface of the image carrier can be effectively reduced. This allows
The life of the discharge product removing device 19 can be extended without hindrance, and the replacement work can be reduced. Also in this case, when removing the discharge products, it is preferable that the discharge product removing device 19 is brought into contact with the surface of the image carrier and the image carrier 1 is rotated at least once.

When the discharge products are removed by bringing the discharge product removing device 19 into contact with the surface of the rotating image carrier 1 when the image forming operation is not performed, the surface of the image carrier is charged by the charger 3. Charged, the surface thereof is not exposed, and a developing bias is applied to the developing roller 8 so that toner does not adhere to the surface of the image bearing member.
It is preferable that no transfer voltage is applied to 1, and that the surface of the image carrier is cleaned by the cleaning device 14 so that toner does not adhere to the discharge product removing device 19 that is in contact with the surface of the image carrier. It is desirable that the sensor 17 always detect the potential of the surface of the image carrier during the image forming operation.

Next, an example of the aforementioned contacting / separating means will be described with reference to FIG.

In FIG. 5, each end in the longitudinal direction of the core shaft 28 of the discharge product removing device 19 is rotatably supported by a bearing 53, and each bearing 53 is provided with a movable side plate 50,
A support 52 is movably supported in a direction approaching or separating from the surface of the image carrier 1 (FIG. 1), and is pressed by a compression spring 54 toward the surface of the image carrier. In FIG. 5, reference numeral F indicates a front side of the image forming apparatus main body, and reference numeral R indicates a rear side of the image forming apparatus main body.

A drive shaft 51 is fixed to the base end of each of the movable side plates 50 and 52, and a swing arm 49 is fixed to an end of the drive shaft 51 on the far side. The drive shaft 51 is rotatably supported by a rear side plate and a front side plate of the image forming apparatus main body (not shown), and the rear side plate is located between the movable side plate 50 and the swing arm 49. The front side plate is located further on the front side than the movable side plate 52. A pin 47 is fixed to the swing arm 49, and the link 47 is connected to the pin 47.
Is connected to the plunger of the solenoid 45 so as to be relatively rotatable. Further, one end of a tension spring 48 is locked to the swing arm 49, and the other end of the spring 48 is locked to a side plate on the back side of the image forming apparatus main body.

When the solenoid 45 is actuated, its plunger is pulled in the direction of arrow A, whereby the drive shaft 51 rotates around its central axis, and the discharge product removing device 19 moves around the central axis of the drive shaft 51. It turns in the direction of arrow C. Thus, the discharge product removing device 19 comes into pressure contact with the surface of the image carrier 1 shown in FIG. Conversely, when the solenoid 45 stops operating, the compression spring 48 pulls the swing arm 49 in the direction of arrow E, whereby the drive shaft 51 rotates in the opposite direction to that described above, and the discharge product removing device 1
9 rotates around the center axis of the drive shaft 51 in the direction of arrow C1, and the discharge product removing device 19 moves away from the surface of the image carrier.

As described above with reference to FIG. 1, when the sensor 35 is provided around the image carrier 1, a detection signal of the sensor 35 is transmitted to the control means comprising the CPU 55 shown in FIG. The operation of the solenoid 45 is controlled by the on / off signal from the CPU 55 as described above.

According to the present invention, a charged image carrier surface is subjected to image exposure, a portion where the absolute value of the surface potential is reduced is defined as a background portion, and a portion where the absolute value is maintained high is defined as an electrostatic latent image.
An image forming apparatus that forms a toner image by adhering toner here, and a toner image on an image carrier made of a photoconductor once,
The present invention can be widely applied to an image forming apparatus that transfers a toner image on an intermediate transfer member onto a recording medium, which is a final transfer material, by transferring the toner image onto a transfer material formed of an intermediate transfer member. In the case of an image forming apparatus having an intermediate transfer member, a discharge product removal device can be brought into contact with the surface of the intermediate transfer member to remove the discharge products adhered to the surface. Constitutes an image carrier, and the recording medium constitutes a transfer material on which a toner image is transferred from the image carrier.

[0064]

According to the first and second aspects of the present invention,
It is possible to provide a discharge product removing apparatus which is small and can efficiently remove discharge products on the surface of the image carrier.

According to the third aspect of the present invention, since the porous member is hydrophilic, the adhesion to the same hydrophilic superabsorbent is enhanced, and the superabsorbent is held by the porous member. Function is enhanced.

According to the fourth aspect of the present invention, since the discharge product removing device is configured as a roller, the discharge products on the surface of the image carrier can be particularly efficiently removed.

According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus having the above-described effects.

According to the invention of claim 6, it is possible to prevent the discharge product removing device from applying a large stress to the image carrier.

According to the seventh aspect of the present invention, the surface of the image carrier immediately after the discharge products are removed by the discharge product removing device can be charged by the charging device. The potential can be made uniform, and a high-quality image can be formed.

According to the eighth aspect of the invention, the life of the discharge product removing device can be extended.

According to the ninth aspect of the present invention, the discharge product removing device can be brought into contact with the image carrier only when necessary, so that the life of the discharge product removing device can be extended more effectively. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic partial cross-sectional view illustrating an example of an image forming apparatus.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an explanatory diagram schematically showing an enlarged view of a hole of a porous member so that the principle of the discharge product removing device shown in FIG. 1 can be easily understood.

FIG. 4 is a perspective view showing another example of the discharge product removing device.

FIG. 5 is a perspective view showing an example of a contact / separation unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 6 Developing device 19 Discharge product removal device 28 Core shaft 29 Porous member 30 Superabsorbent material 31 Hole 35 Sensor P Transfer material

Continued on the front page (72) Inventor Hiromitsu Takagaki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Aino Noguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Company F term (for reference) 2H027 DA02 DE07 DE09 EA09 EC14 ED27 EE06 EF07 EF12 EF13 JA02 2H034 AA06 BA01 BA05 BC02 BC03 BC07 BC10 3J103 AA02 AA13 AA32 BA41 FA06 FA07 FA15 FA18 FA19 GA02 GA52 HA03 HA04 HA05 HA53 HA41 HA05 HA53

Claims (9)

[Claims] 1. A discharge product removing apparatus characterized in that a powdery superabsorbent substance is held in pores of a porous member. 2. The discharge product removing apparatus according to claim 1, wherein the superabsorbent material is held in the holes in a state of being swollen with water. 3. The discharge product removing device according to claim 1, wherein the porous member is made of an elastic material having hydrophilicity. 4. The porous member according to claim 1, wherein the porous member is concentrically fixed to the outside of a core shaft, and the porous member and the core shaft are formed in a rotatable roller shape. Discharge product removal device. 5. The surface is supported for movement, and
An image carrier on which a toner image is formed, and the discharge product removing device according to any one of claims 1 to 4,
The discharge product removing device is an image forming device wherein at least a super absorbent material swollen with water comes into direct contact with the surface of the image carrier. 6. The image forming apparatus according to claim 5, wherein the discharge product removing device abuts on the surface of the image carrier while rotating following the movement of the surface of the image carrier. 7. A charging device for charging the surface of an image carrier, a latent image forming means for forming an electrostatic latent image on the surface of the image carrier charged by the charging device, and using the electrostatic latent image as a toner image A developing device for visualizing the image, and a transfer device for transferring the toner image to a transfer material, wherein the discharge product removing device is located on the upstream side of the charging device with respect to the moving direction of the surface of the image carrier. The image forming apparatus according to claim 5, wherein the image forming apparatus contacts a surface portion of the image carrier downstream of a transfer position of the toner image by the transfer device. 8. The apparatus according to claim 5, further comprising a contact / separation means for operating the discharge product removing device so that the discharge product removing device comes into contact with or separates from the surface of the image carrier. An image forming apparatus according to claim 1. 9. A sensor for detecting a state of adhesion of a discharge product to a surface of an image carrier, and a sensor for generating a discharge when it is detected that a predetermined amount of the discharge product adheres to the surface of the image carrier. 9. The image forming apparatus according to claim 8, further comprising control means for controlling the contact / separation means so that the object removing device contacts the surface of the image carrier.