JPH02208686A - Cleaning method - Google Patents

Abstract

PURPOSE:To prevent image quality from being deteriorated and to stabilize electrostatic characteristic in repetitive use by wiping off adhesive matter on a photoconductor with the aid of nonwoven fabric impregnated with clean liquid. CONSTITUTION:A cleaning device 20 is provided with a supply roll 51 for supplying the nonwoven fabric 50 having a layer consisting essentially of unused natural fiber, a take-up roll 52 for taking up the nonwoven fabric 50 already used and a pressing roll 54 for making the unused nonwoven fabric 50 impregnated with the clean liquid CL and pressing the nonwoven fabric 50 impregnated with the clean liquid CL to the surface of the photoconductor 10. Furthermore, the device 20 is provided with a guiding roll 55 and nip rolls 56 and 56 which constitute a conveyance system and a fan 57 for drying a drum installed on the downstream side of the pressing roll 54. By moving the nonwoven fabric 50, remaining toner, stain or the adhesive matter such as dust, etc., are wiped off. The adhesive matter is acclimatized to the clean liquid CL so as to be effectively removed without damaging the surface of the photoconductor 10 and a high-quality high-gradation continuous tone image is stably obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a cleaning method applied to an electrophotographic printer that records images by electrophotography, and more particularly, to a cleaning method applied to an electrophotographic printer that records images by electrophotography. The present invention relates to a cleaning method for cleaning the surface of the photoconductor using a nonwoven fabric having a layer mainly composed of natural fibers and impregnated with a cleaning solution to remove deposits on the photoconductor before forming a latent image.

(Prior art) Conventionally, an electrostatic latent image is formed by irradiating a negative-like charged photoconductor with a light beam modulated based on an image signal responsible for a continuous tone image, and the rest is carried out using a conventional dry method. Alternatively, an image recording method is known in which a hard copy of the above image is formed by a wet electrophotographic process.

Furthermore, various electrophotographic methods have been proposed in the past that allow continuous-tone images to be recorded with good gradation reproducibility. For example, in Japanese Patent Publication No. 49-38172 filed by the present applicant, after an electrostatic latent image formed on a photoconductor is developed into a toner image using a liquid developer (hereinafter referred to as "developer"), this toner image is A wet electrophotographic process is disclosed in which the toner image is removed by pressing an adhesive tape and then adhering the tape to a final support.

The developer mentioned above is made by dispersing fine toner particles with an electric charge in an insulating liquid, and the toner particle diameter is usually 0.1 to 1.0 μI, which is smaller than that of a dry developer. , which is advantageous for recording continuous tone images.

In the dry electrophotographic process, a so-called electrostatic transfer method is used to electrostatically transfer a toner image formed on a photoconductor using a magnetic brush development method or the like onto a support such as paper using a corotron. is widespread, but
This transfer method has a problem in that the transfer efficiency in high density areas and low density areas is poor.

On the other hand, the so-called adhesive transfer method in which a toner image is transferred to the adhesive layer described above has a transfer efficiency of 10% regardless of the image density.
Since it is close to 0%, this is also advantageous for recording continuous tone images.

By the way, in the dry and wet electrophotographic methods,
Since the photoconductor is used continuously and repeatedly, the toner image formed on the photoconductor is transferred to a sheet such as paper or adhesive tape, and after the static electricity is removed, before the next image recording, The photoconductor is cleaned to remove toner, dirt, dust, and other deposits remaining on the photoconductor and to clean the outer surface of the photoconductor.

Conventionally, cleaning methods for cleaning photoconductors in dry electrophotography include blade method, brush roll method,
The felt method, roll method, web method, etc. are used. In the blade method, deposits are scraped off from the outer surface of the photoconductor using a rubber blade, but the cleaning performance is low. In the brush roll method, deposits are brushed off from the photoconductor using a rotating brush and removed using a suction device.
Scratches tend to occur because the photoconductor is rubbed with a brush.In the felt method, a felt pad is brought into pressure-sliding contact with the photoconductor, but it is difficult to adjust the pressure. This will damage the photoconductor. The roll method uses a nonwoven fabric roll to adsorb deposits on the photoconductor surface, and the web method uses a nonwoven fabric to sequentially scrape off deposits on the photoconductor.The cleaning performance is compared to the above methods. However, there is a problem that the cleaning performance is limited and lacks stability simply by contact adsorption.

In addition, a photosensitive drum cleaner with improved cleaning performance is disclosed in JP-A-62-112188. This cleaner is a photosensitive drum cleaner made by charging a non-woven fabric containing 20 to 100% by weight of polyolefin fibers in the roll method or web method, and by including 20 to 100% by weight of polyolefin fibers. The purpose of this method is to sufficiently improve the charging effect of the nonwoven fabric, and in addition to the physical adsorption effect of the nonwoven fabric, use the electric bow absorption force due to the charging effect to obtain cleaning performance even better than that of conventional methods.

On the other hand, conventionally, in the above-mentioned wet electrophotography method, a cleaning method using a cleaning roll and a cleaning blade has been used, as shown in FIG.

In the image recording apparatus that performs the wet electrophotography method shown in FIG. By rotating in the A direction, it is uniformly charged by the charger 12, and is irradiated with a light beam 23 modulated based on the image signal in the exposure section 13, so that an electrostatic latent image of the image is formed on the photoconductor 10. is formed.
This electrostatic latent image is developed into a high-gradation continuous-tone toner image using a liquid developer F in which charged toner particles are dispersed in a wet type developer 14.

After development, the photosensitive drum 11 is dried by a drum drying corona discharger 15 and a drum drying fan 16.
The toner image is dried.

Next, using the transfer roller 30 constituting the adhesive transfer means 17, the adhesive surface 1 of the image receiving sheet 2 is pressed against the photoconductor 10 to transfer the toner image onto the image receiving sheet 2. Thereafter, the image-receiving sheet 2 is attached to a support such as paper, and the above-mentioned high-gradation continuous-tone image is printed.

On the other hand, after the photoconductor 10 has been transferred, the static electricity is removed by the static eliminator 18, but the remaining toner, dirt, dust, and other deposits adhere to the photoconductor 10, and these deposits are removed with liquid. The photoconductor 10 is cleaned with a cleaning roll 90 made of a sponge or the like impregnated with a liquid excluding the developer or some of its components, and a cleaning blade 9f made of urethane rubber or the like is pressed against the photoconductor 10 to remove deposits and clean it. The liquid is discharged to the outside and the photoconductor 10
is being cleaned.

By the way, if you use this method for cleaning,
Since toner adheres to the tip of the cleaning roll 90 and cleaning blade 91, the surface of the photoconductor 10 is easily scratched.In addition, if the photoconductor 10 is not cleaned, remove the cleaning roll after cleaning is completed. When the cleaning blade 90 and the cleaning blade 91 are pulled up to remove them from the contact position with the photoconductor 10 as shown by the arrows in the figure, the liquid used for the cleaning may flow out or be scattered, causing the erase lamp 21 in the peripheral area to be removed. There are problems such as deterioration of image quality and reliability due to contamination of the charger 12 and the like.

Therefore, as a method for solving these problems, the present applicant proposed in Japanese Patent Application No. 63-82612 a method of impregnating a cleaning liquid to remove deposits such as toner particles, dirt, and dust remaining on the photoconductor. We have proposed a cleaning method in which cleaning materials are sequentially wiped using a flexible substrate, and an apparatus for carrying out this method.

<Problems to be Solved by the Invention> By the way, the photoconductor drum cleaner disclosed in JP-A No. 62-112188 uses a nonwoven fabric with a good charging effect, so it is difficult to use the photoconductor drum cleaner in dry electrophotography. It is extremely effective against toner particles, foreign matter, magnetic powder, etc. that are electrically attached to the photoconductor, but it is extremely effective against toner particles that are stuck to the photoconductor due to dirt stuck on the photoconductor or toner particles that are strongly attached to the photoconductor due to wet development or adhesive transfer. To wipe away dirt, dust, and other deposits, it is necessary to press the nonwoven fabric strongly against the photoconductor. Pressing too hard may damage the photoconductor or adversely affect the charging characteristics of the photoconductor. There's a problem. Therefore, cleaning using this cleaner tends to cause unevenness and blurring in the reproduced image, making it impossible to obtain a continuous tone image with high gradation and high image quality.

Furthermore, the cleaning method proposed in Japanese Patent Application No. 82612/1983 by the present applicant cleans the photoconductor by pressing a flexible substrate impregnated with a cleaning liquid against the photoconductor and moving it six times. , it is possible to cleanly remove toner dirt, dust, and other deposits on the photoconductor without damaging the photoconductor, and there is no need to worry about scattering the cleaning solution containing the deposits to the surrounding area, resulting in a stable high-level cleaning solution. This is an excellent cleaning method for cleaning photoconductors so that high quality continuous tone images can be obtained.

However, in order to consistently obtain high-gradation, high-quality continuous-tone images, it was found that it was necessary to strictly select the flexible substrate, but the cleaning method described above does not address these points. has not been sufficiently considered.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a photoconductor of a photoreceptor drum used in wet electrophotography, which is mainly composed of natural fibers impregnated with a cleaning liquid, when used repeatedly. By wiping away deposits on the photoconductor with a nonwoven fabric having a layer, it is possible to prevent image quality deterioration such as image unevenness, blurring, and running, and to stabilize electrostatic characteristics during repeated use. To provide a cleaning method that can be used.

Means for Solving the Problems> In order to achieve the above object, the present inventors have conducted extensive research on cleaning methods that prevent image quality deterioration and repeatedly stabilize electrostatic characteristics. , special request 1976
Depending on the type of flexible substrate proposed in No. 3-82612, it may slightly affect the charging characteristics of the photoconductor after cleaning, or if a continuous tone image is formed on the photoconductor after cleaning, said image may be blurred. In contrast, nonwoven fabrics with a layer mainly composed of natural fibers do not cause any deterioration in image quality, and the repeatability of electrostatic properties is significantly better than before. This led to the present invention.

That is, in the present invention, before forming an electrostatic latent image on a photoconductor disposed on the outer peripheral surface of a photoreceptor drum, a nonwoven fabric having a layer mainly composed of natural fibers is impregnated with a cleaning liquid, and the nonwoven fabric is The present invention provides a cleaning method characterized in that the surface of the photoconductor is cleaned by moving the photoconductor while bringing it into contact with the photoconductor.

The present invention will be explained in more detail below.

The cleaning method of the present invention removes toner, dirt, dust, and other deposits remaining on a photoconductor after a toner image is transferred, and cleans the photoconductor before reusing the photoconductor. A method in which a nonwoven fabric impregnated with a cleaning liquid and having a layer mainly composed of natural fibers is moved while in contact with the photoconductor, and the deposits are constantly wiped with a clean new nonwoven fabric. It is.

If the nonwoven fabric having a layer mainly composed of natural fibers used in the present invention has a layer mainly composed of natural fibers,
The non-woven fabric may have any number of layers, but it may be a layer that can be brought into contact with the photoconductor surface of the photoreceptor drum, either directly or through another thin fiber layer. For example, as typically shown in FIG. 1a, a nonwoven fabric consisting of only a layer 6 mainly composed of natural fibers, as shown in FIG. 1b, a layer mainly composed of natural fibers. 6 and a back fiber layer 7,
and a nonwoven fabric having a three-layer structure including a layer 6 containing natural fibers as a main component, a surface fiber layer 8, and a back surface fiber layer.

Here, the layer 6 mainly composed of natural fibers may be made of only natural fibers, or may be a nonwoven fabric made by mixing natural fibers with synthetic fibers, semi-synthetic fibers (regenerated fibers), or the like. In the case of forming a non-woven fabric, it is preferable to contain natural fibers in an amount of 50 wt% or more, more preferably 70 wt% or more. Here, as natural fibers,
Any material may be used as long as it has low chargeability, wettability to the cleaning liquid, and flexibility, but pulp and cotton are typically preferred. Further, the layer 6 mainly composed of natural fibers of the present invention may be a water-absorbing paper made of natural bulbs.

The synthetic fibers and semi-synthetic fibers to be mixed with the natural fibers are not particularly limited, but preferably have low electrostatic properties, wettability with cleaning liquid, and flexibility. Examples include synthetic fibers and recycled fibers such as polyethylene, polypropylene, nylon, polyamide, polyester, polyacrylonitrile, acetate, and rayon.

The surface of the nonwoven fabric of layer 6, which is mainly composed of natural fibers, is not particularly limited, but since it directly contacts the photoconductor of the photoreceptor drum, it has flexibility and does not damage the photoconductor during use. , fluff may be present on the surface of the nonwoven fabric as long as the fluff does not adhere to the photoconductor.

Further, the layer 6 mainly composed of natural fibers may be a single layer or a multilayer, and may be a multi-layered stack of layers mainly composed of natural fibers having different components and contents. Good too.

The back fiber layer 7 is not a layer that comes into direct contact with the photoconductor of the photoreceptor drum, so there is no restriction at all as long as it has wettability to the cleaning solution, and it can be made of natural fibers, synthetic fibers, semi-synthetic Mll fibers, or mixtures thereof. It may be made of nonwoven fabric, and may be a single layer or multiple layers.

Since the surface fibers 1a directly contact the photoconductor of the photoreceptor drum, they are wettable with the cleaning liquid and have flexibility.
The fabric is not particularly limited as long as it does not damage the photoconductor and does not cause fuzz to adhere to the photoconductor during use, and may be made of a nonwoven fabric made of natural fibers, synthetic fibers, semi-synthetic fibers, or mixtures thereof. It can be single-layer or multi-layer.
Further, the thickness of the surface fiber layer 8 is preferably thinner than the layer 6 mainly composed of natural fibers, and more preferably as thin as possible.

A known method can be used to make the above-mentioned fiber into a non-woven fabric.

As the cleaning liquid used in the present invention, any cleaning liquid can be used as long as it is compatible with the toner contained in the developer and does not corrode or stain the photoreceptor drum or photoconductor. In other words, any material that can be cleaned by removing deposits such as toner from the photoconductor and does not impair the properties of the photoconductor, particularly the electrical properties, may be used. For example, in wet electrophotography, toner When a liquid developer in which charged toner particles are dispersed in an insulating carrier liquid is used as the developer, the insulating carrier liquid of the liquid developer is preferably used.

Furthermore, it is preferable that the direction of movement of the nonwoven fabric is opposite to the direction of movement of the photoconductor so that a new area can always be sufficiently wiped.

Although the cleaning method according to the present invention is basically configured as described above, an apparatus for carrying out the cleaning method according to the present invention will be described in detail below based on a preferred embodiment shown in the accompanying drawings.

FIG. 2 is a schematic diagram showing an example of an electrophotographic printer incorporating a cleaning device that implements the cleaning method of the present invention.

The illustrated apparatus has a photoconductor drum 11 having a photoconductor 10 arranged on its circumferential surface, and the photoconductor drum 11 is rotated in the direction of arrow A by a driving means (not shown). Around the photosensitive drum 11, along the rotational direction of the drum 11, there is a charger 12, an exposure section 13, a wet type developer 14, a squeeze roller 15a, a blade 15b1, a drum drying fan 16, an adhesive transfer means 17, and a static eliminator. 18, a cleaning device 2σ, and an erasing lamp 21.

For example, the surface of the photoconductor 10 of the photosensitive drum 11 is made of Si.
A-3T (amorphous silicon) photoreceptor coated with C (silicon carbide), 0PC (organic photoconductor photoreceptor, selenium photoreceptor, selenium alloy photoreceptor, cadmium sulfide photoreceptor, composite multilayer photoreceptor of these, etc.) However, SiC-coated a-3i is more preferable.

The exposure section 13 includes a laser light source 22 made of, for example, a semiconductor laser, a He-Ne laser, and the like.
An optical modulator 24 such as an AOM (acousto-optic modulator) that modulates the intensity of a light beam (laser beam) 23 emitted from the laser beam, a modulation circuit 25 that drives the optical modulator 24, and a modulated light beam. 23 is reflected and deflected to form a photoconductor 1.
0, an optical deflector 26 such as a polygon mirror that scans in a direction substantially perpendicular to the direction of rotation of the photoreceptor (direction of arrow A);
It includes a scanning lens 27 made of an fθ lens that focuses the light beam 23 onto the photoconductor 10 to a uniform beam diameter.

The modulation circuit 25 is connected to an image supply 92B that supplies a digital image signal Sd via a correction table 29a and a D/A converter 29b that converts the digital image signal Sd into an analog image signal S.

The wet type developer 14 uses a liquid developer (developing solution) in which charged fine toner particles are dispersed in an insulating carrier liquid.
Any device that can supply F to the electrostatic latent image on the photoconductor 10 may be used, but for example,
The liquid developing device disclosed in Japanese Patent No. 1-52216 can be used.

The preferred liquid developer F used in the present invention is composed of a pigment forming toner particles, a coating agent, a fixing agent, a dispersant, a charge control agent, and an insulating carrier liquid, but without departing from the spirit of the present invention. However, it is not limited to this.

As the insulating carrier liquid for the liquid developer F, any liquid may be used as long as it has an electric resistance of 1010 Ω·cm or more, a low dielectric constant, is nontoxic, and does not attack the photoreceptor so as not to cause leakage of the electrostatic latent image. , for example, normal paraffin,
Any of isoparaffin-based, olefin-based, and naphtha-based liquid hydrocarbons or those containing aromatic hydrocarbons can be used. More preferable examples include Isopar G1 Isopart 1 Isopar L1 Tsurupetu, which is commercially available from Esso Standard Co., Ltd., and these may be used alone or in combination of two or more. Good too.

Here, when forming a color image, Y (yellow)
Three-color wet developer 14Y for toner, wet developer 14M% for M (magenta), wet developer 14C for C (cyan), or four-color wet developer including wet developer 14B for B (black). It is structured so that the containers can be replaced one after another.

The squeeze roller 15a rotates at a relatively high speed in the direction of the arrow in the figure to squeeze the insulating liquid adhering to the toner image developed by the wet developer 14 from the surface of the photoconductor 10. 15b transfers the insulating liquid squeezed by the squeeze roller 15a to the squeeze roller 1.
It is scraped off from the surface of 5a. Thereafter, the toner image on the photoconductor 10 squeezed with the insulating liquid is dried by the drum drying fan 16.

The adhesive transfer means 17 includes a transfer roller 30 movable in the directions of arrows B and B' by a known method, an image-receiving sheet supply roller 31 that winds and stores a transparent image-receiving sheet 2 having an adhesive surface 1, and a separation roller. Nip rollers 32A, 32B that sandwich the image receiving sheet 2 stuck to the paper pattern or release film (hereinafter referred to as release sheet) 3, and the release sheet 3 that has been peeled off.
and a release sheet winding roller 33 for winding up the release sheet.

Further, downstream of the transfer roller 30, there is a support sheet supply roller 41 that winds and stores the support sheet 4, and a support sheet supply roller 41 that stores the support sheet 4 by winding it.
a pair of pressure rollers 40A for pressure-bonding the image receiving sheet 2 and the image receiving sheet 2;
40B and a cutter 42 are provided. Further, each of the pressure rollers 40A and 40B has a heat source H0H2 inside.

The cleaning device 20 includes a supply roll 51 for supplying an unused nonwoven fabric (hereinafter simply referred to as nonwoven fabric) 50 having a layer mainly composed of natural fibers, and a supply roll 51 for winding up the used nonwoven fabric 50. The winding roll 52 and the unused nonwoven fabric 50 are impregnated with the cleaning liquid CL, and the cleaning liquid C
A press roll 54 that presses the nonwoven fabric 50 impregnated with L onto the surface of the photoconductor 10, a guide roll 55 and nip rolls 56, 56 that constitute the conveyance system, and a drum drying fan 57 on the downstream side of the press roll 54. and has.
The take-up roll 52 is driven by known means (not shown).

As shown in the figure, it is preferable that the nonwoven fabric 50 is moved in the opposite direction to the moving direction of the photoreceptor drum 11, but the present invention is not limited to this, and the supply roll and take-up roll are replaced, and the photoreceptor drum 11 is moved in the opposite direction. It may move in the same direction as the moving direction of the drum 11.

As shown in FIGS. 3 and 4, the pressure roll 54 is
It has a hollow part 58 for storing the cleaning liquid CL therein, and a capillary tube 60 that communicates the hollow part 58 with the outer surface of the press roll 54. Furthermore, pressure roll shafts 61 and 62 are attached to protrude from the centers of both ends of the pressure roll 54, and bearings 63 are interposed between these roll shafts 61 and 62 and both end surfaces of the pressure roll 54. , non-woven fabric 50-8
The pressure roll 54 is configured to rotate according to the motion. Furthermore, the roll shaft 61 has a through hole 6 at its center.
5. A liquid sending pipe 66 is inserted into this through hole 65 by a known method.
It is configured to be connected to the stem. Liquid sending vibe 66
is connected to a liquid sending pump for cleaning liquid CL stored in a storage tank (not shown). In the example shown in FIG.
L passes through the roll shaft 61 and the hollow part 58 of the pressure roll 54
However, the present invention is not limited thereto, either through the roll shaft 62 or through both roll shafts 61.6.
The cleaning liquid CL may be supplied through 2.

Here, the capillary tube 60 communicating between the outer surface of the press roll 54 and the inner hollow part 58 exudes the cleaning liquid CL stored in the hollow part 58 and is wound around the outer surface of the press roll 54. The material is for impregnating the nonwoven fabric 50, and its shape, dimensions, and arrangement are not particularly limited, and may vary depending on the degree of dirt on the photoconductor 10 to be wiped, the photosensitive drum 1, etc.
1 rotation speed, the cleaning liquid C in the hollow part 58 of the pressure roll 54
It is preferable to window it appropriately depending on the amount of L and the moving speed of the non-woven fabric 50. Dirt adhering to the photoconductor 10 can be removed by using as little cleaning liquid CL as possible and using as little non-woven fabric 50, that is, with a small moving amount. It is preferable to wipe cleanly, so apply a small amount of cleaning liquid CL evenly onto the non-woven cloth 5 as soon as possible.
It is better to include it in 0.

Therefore, it is preferable to provide a large number of capillary tubes 60 with a diameter as small as possible on the pressure roll 54. It is preferable that the capillary tubes 60 are arranged as uniformly as possible, for example, in a staggered manner.

The amount of cleaning liquid CL stored in the hollow part 58 of the pressing roll 54 is not particularly limited as long as the amount of cleaning liquid CL seeping out through the capillary tube 60 can uniformly wet the nonwoven fabric 50. 60, the moving speed of the nonwoven fabric 50, etc., the window may be adjusted as appropriate.

The nonwoven fabric having a layer mainly composed of natural fibers used here can wipe off deposits such as toner particles, dirt, and dust together with the cleaning liquid CL without damaging the photoconductor 10.
The electrical characteristics of the photoconductor 10 can be restored to the optimal state for high-gradation, high-quality continuous-tone images, and the above-mentioned nonwoven fabric is used.

Here, as the cleaning liquid CL used, the cleaning liquid described above can be used.

Further, the pressure roll 54 is movable in the direction of the arrow in the figure by a means not shown, and when in use, the pressure roll 54 is movable in the direction of the arrow in the figure.
It is configured so that it can be firmly contacted and pressed against the upper photoconductor 10 and can be removed from the contact position when not in use.

Further, as shown in FIGS. 5 and 6, the pressure roll 5
A rod 67 may be stored in the hollow portion 58 of 4. The rod 67 is preferably a round rod having a length approximately equal to the width of the nonwoven fabric 50. When the bar 67 is stored in the hollow part 58 of the press roll 54, the cleaning liquid CL introduced into the hollow part 58 travels along the surface of the bar 67 very quickly and spreads over the entire lower surface of the hollow part 58, and the cleaning liquid CL is Due to the surface tension of CL, the cleaning liquid CL is stored in a meniscus shape as shown in FIG. 5, and oozes out from the capillary tube 60 to uniformly impregnate the nonwoven fabric 50 with the cleaning liquid CL. Furthermore, since the bar 67 is housed in the hollow part 58, even if the suppression roll 54 is tilted to some extent, the cleaning liquid CL will be stored in the meniscus between the bar 67 and the hollow part 58, so that the capillary The amount of cleaning liquid CL that seeps out from 60 does not change in the width direction of press roll 54, so that nonwoven fabric 50 can always be wetted with an appropriate amount of cleaning liquid CL.

The bar 6 is preferably stored unfixed near the lower end of the hollow portion 58. The cleaning liquid CL is supplied to the hollow portion 58 of the pressure roll 54 through the through hole 65 of the roll shaft 61. Since it oozes out into the nonwoven fabric 50 through the capillary tube 60, in order to keep the oozing amount constant, the supply amount can be kept constant, but since there is always variation in the supply amount,
It is necessary to store a certain amount of cleaning liquid CL in the hollow part 58. However, due to the rod 67, the cleaning liquid CL is
Since it is stored in the meniscus between 7 and the hollow part 58,
The amount of cleaning liquid CL stored in the hollow portion 58 can be made small, and the amount seeping out can be kept constant at all times.

In the example shown in FIGS. 4 and 6, a bearing 63.63 is inserted between the pressure roll 54 and the pressure roll shaft 61.62, so that the pressure roll shaft 61.62 is not rotated, and only the pressure roll 54 is rotated. Although it was configured to rotate,
The present invention is not limited to this, and the pressure roll 54 and the pressure roll shaft 61.62 may be configured to be integrated and rotated. In this case, the roll shaft 81.62 A bearing 63 is provided to rotatably support it.

Therefore, the liquid sending vibrator 6 supplies the cleaning liquid CL to the through hole 65 provided in at least one of the roll shafts 61 and 62.
6 cannot be connected directly, so it is connected by a known member such as a rotary joint that connects a rotating pipe and a fixed pipe.

The apparatus for carrying out the cleaning method according to the present invention is basically constructed as described above, and its operation will be explained below.

During image recording, the photosensitive drum 11 is rotated as described above. Then, the digital image signal Sd carrying the continuous tone image is passed from the image signal supply device 28 to the correction table 29a.
The image signal S sent to the A/A converter 29b and analogized by the D/Af converter 29b is sent to the above-mentioned modulation circuit 25.
sent to. Note that the image signal Sd is gradation-converted by the correction table 29b. The modulation circuit 25 drives the optical modulator 24 based on the image signal S, whereby the intensity of the light beam 23 is modulated in accordance with the image signal S.

By rotating the photosensitive drum 11 as described above,
The photoconductor 10 is moved relative to the charger 12 and is uniformly charged by the charger 12 in the process. The --like charged photoconductor 10 is irradiated with the light beam 23 deflected by the light deflector 26 as described above. The light beam 23 scans the photoconductor 10 one-dimensionally by the deflection (main scanning). Also, by rotating the photoreceptor drum 11, the light beam 23 performs sub-scanning, and eventually the photoconductor 10 is exposed to light. It is scanned two-dimensionally by the beam 23.

As mentioned above, this light beam 23 is modulated based on the image signal S, and therefore, the electrostatic potential of the image carried by the image signal S appears on the photoconductor 10 irradiated with this light beam 23. An image is formed.

This electrostatic latent image is developed into a toner image by a wet developer 14. This wet type developing device 14 brings a liquid developer F, which is made by dispersing fine charged toner particles in an insulating liquid, into contact with the photoconductor 10, and causes the toner particles to be attached to the photoconductor 10 by electrostatic attraction. By adhering, the electrostatic latent image is developed with toner. The density of the toner image thus formed changes in accordance with the intensity modulation of the light beam 23, and the gradation of the continuous tone image carried by the image signal S is reproduced. After this development, the photosensitive drum 11 is dried by the squeeze roller 15a, blade 15b, drum drying fan 16, and the like.

The dried toner image is moved to position P by rotation of the photosensitive drum 11.

On the other hand, the image-receiving sheet 2 is sent out from the image-receiving sheet supply roller 31 while being stuck to the belt-shaped release sheet 3, and is separated from the release sheet 3 at a position where it is nipped by the nip rollers 32A and 32B.

Release paper sheet 3! The separated image-receiving sheet 2 is suspended on the transfer roller 30 with the adhesive surface 1 outside, while the peeled-off release sheet 3 is suspended on the release sheet take-up roller 3.
3.

When it is detected or determined by known means that the toner-developed portion of the photoconductor 10 has been conveyed to just before the position P+ facing the transfer roller 30,
The transfer roller 30, which had been separated from the photoreceptor drum 11 until then, moves in the direction B so as to press against the photoreceptor drum 11 at a position P.

In this way, the transfer roller 30 moves and the photosensitive drum 11
As a result, the transfer roller 30 rotates as a result of the photoreceptor drum 11 , and the adhesive surface 1 side of the image receiving sheet 2 suspended thereon is pressed against the outer peripheral surface of the photoreceptor drum 11 . The toner image on the photoconductor 10 on the outer peripheral surface is adhesively transferred to the adhesive surface 1 of the image receiving sheet 2.

After that, the transfer roller 30. moves in the direction B' and separates from the photosensitive drum 11.

The image receiving sheet 2, on which the toner image on the photoconductor 10 on the outer surface of the photosensitive drum 11 has been adhesively transferred, is sent between the heated pressure rollers 40A and 40B, and then sent out from the image receiving sheet 2 and the support sheet supply roller 41. A supporting sheet 4 is attached thereto.

Next, the pasted image-receiving sheet 2 and support sheet 4 are cut into a predetermined length by a cutter 42 to form a high-gradation continuous-tone print image.

In the case of color image formation, for example, toner developer F corresponding to three types of Y (yellow), M (magenta), and C (cyan), or 4 fi, which is the addition of B (black) to these, is filled. Using the wet developing device 23, among the above processes, charging, exposure, development, and transfer are sequentially performed, and the image receiving sheets to which the Y, M%C, and B toner images have been transferred are sequentially attached to the same support sheet. A color image can be formed by this method.

On the other hand, the photoconductor 10 to which the toner image has been transferred rotates together with the photosensitive drum 11 in the direction of arrow A, and is neutralized by a static eliminator 18 as the case may be.

Thereafter, before the tip position of the photoconductor 10 where the toner image was formed comes into contact with the press roll 54 of the cleaning device 20, the liquid is passed from the liquid sending vibrator 66 through the through hole 65 to the hollow part of the press roll 54. The supply of the cleaning liquid CL is started at 58, and a predetermined amount of the cleaning liquid CL is stored in the hollow part 58, and at the same time passes through the capillary tube 60 to uniformly wet the nonwoven fabric 50.
On the other hand, the supply roll 51 and the take-up roll 52 are
0 begins to move very slowly, and the pressure roll 5
4 to the contact position, and apply cleaning liquid CL to the photoconductor 10.
A nonwoven fabric 50 uniformly impregnated with a small amount of

In this way, toner stains remaining on the photoconductor 10,
The surface of the photoconductor 10 is cleaned by wiping away deposits such as dust with the nonwoven fabric 50, together with a small amount of cleaning liquid CL impregnated therewith. At this time, since the nonwoven fabric 50 is moved in the opposite direction to the moving direction of the photoconductor 10, a new part always comes into contact with the photoconductor 10, without damaging the photoconductor 10, and without scattering toner particles or cleaning liquid CL. Therefore, the surface of the photoconductor 10 can be suitably cleaned and the electrical properties of the photoconductor 10, such as electrostatic properties and gradation properties, can be restored.

Thereafter, the cleaning liquid CL remaining on the photoconductor 10 is dried by a drum drying fan 57.

Thereafter, the residual latent image on the photoconductor 10 is erased by an erasing lamp 21, and the photoconductor 10 is reused.

In the present invention, since a nonwoven fabric having a layer mainly composed of natural fibers is used as the nonwoven fabric 50, the cleaning liquid CL
It is possible to quickly and uniformly impregnate the photoconductor 10 with the toner, dirt, dust, etc. on the photoconductor 10 by blending it with the cleaning liquid and effectively wiping it off without damaging the photoconductor 10.

In addition, the most characteristic feature of cleaning using a nonwoven fabric mainly composed of natural fibers impregnated with the cleaning solution of the present invention is that cleaning does not adversely affect the electrical characteristics, development characteristics, etc. of the photoconductor 10; It is possible to reproduce the photoconductor 10 with less variation each time without deteriorating its electrical characteristics such as electrostatic characteristics and gradation characteristics when it is reused later.

Therefore, in the electrophotographic method using the cleaning method of the present invention, it is possible to stably form a large number of high quality, high gradation continuous tone images without deteriorating the image quality.

When obtaining a large number of printed images, the photoconductor 10 is used repeatedly in a process similar to that described above, that is, a process of charging, exposure, development, transfer, and cleaning (including static elimination).

In the electrophotographic printer shown in FIG. 2, if the photoconductor drum 11 is stopped without sufficiently cleaning the photoconductor 10 after image formation, toner stains that have adhered to the photoconductor 10 during reuse, The quality of the first few images may deteriorate due to dirt and other deposits. Therefore, in the present invention, consideration is given to the drive sequence, etc. so that the photoconductor 10 is thoroughly cleaned when the use of the photoconductor 10 is finished and before the first image formation is started. It is preferable to keep it.

The apparatus for carrying out the cleaning method according to the present invention has been described above with reference to FIGS. 2 to 6. The pressing means and the means for moving the nonwoven fabric are not limited to these, but the nonwoven fabric is
Various configurations are possible, such as immersion in a cleaning liquid tank or spray coating, or configuring the outer peripheral surface of the roll with the nonwoven fabric.

<Experiment example> The present invention will be specifically explained below based on experimental examples.

(Experiment Example 1) Se-Te photoreceptor, OPC (organic photoconductor) photoreceptor,
Using a-5i (amorphous silicon) photoreceptor,
Tests were conducted on the repeated stability of electrostatic properties with and without the cleaning method of the present invention.

For charging, these photoreceptors are uniformly charged using the same charger, and for erasing, static electricity is removed by AC corona discharge, or light irradiation is performed with an eraser lamp (eraser lamp), or both of these are performed. The charge on the photoreceptor was erased.

In addition, in order to improve the repeat stability of electrostatic characteristics for some of the devices that are erased using an erase lamp, the light intensity and wavelength of the eraser light from the erase lamp were optimized and adjusted.

Table 1 shows the various processing conditions mentioned above.

Charging and erasing were repeated a total of 30 times under the same charging conditions while satisfying these processing conditions, and the variation in the charging potential of the photoreceptor at that time, that is, the repeatability of the charging potential was measured. The results are shown in Table 1.

The variation in charging potential can be determined by measuring the charging potential v0 each time in the 30 repetitions process, and calculating the average value vo,
■ Maximum value. ′aaw When the minimum value is yosin, Δ■. =■. It was expressed as whax y01n Δ”X100%.

v.

Next, in the same manner as above, a process of repeating charging, exposing, and erasing was performed a total of 30 times so as to satisfy the various processing conditions shown in Table 1. Here, before exposure is the charged potential ■ of the photoreceptor before exposure.

is measured, and during exposure, a step wedge consisting of 10 steps is used to set the exposure amount E+ (1=1
．． 10) by simultaneously irradiating each potential V after exposure.
(E+) (i=1°10) is measured, and the exposure amount dependence of the surface potential of the photoreceptor, that is, the gradation characteristic curve (V-nog
E) was found.

The repeatability of the gradation characteristic, which indicates how much the gradation characteristic changes by repeating the process, ie, the variation amount Δ(V-JLogE) of the gradation characteristic, was determined as follows.

That is, in the process of repeating the charging-exposure-erasing process a total of 30 times, each time vo, V(E+)(i-x,
10) is measured, and after repeating this 30 times, (i-1, 10) is determined for each exposure amount, and the maximum value is defined as the variation amount Δ(V - IL ogE ) of the gradation characteristics. did.

Therefore, as shown in FIG. 8, Δ(V - ItogE ) is calculated by overlapping the gradation characteristic curves normalized by the surface potential before exposure obtained in the above process 30 times to obtain a constant exposure amount. It can also be defined as the maximum potential fluctuation rate at .

The amount of variation △(V
-42ogE) results are also shown in Table 1.

(Example 2) Next, using the cleaning device and electrophotographic printer shown in FIGS. 2, 3, and 4, images formed using various nonwoven fabrics were measured in terms of resolution (lines/mm) and Evaluation was made based on image blur and flow. Here, the resolution was evaluated visually by forming an image using a resolution test pattern using a projection exposure system, magnifying the image 50 times with a microscope. In addition, image blur and flow were visually evaluated.

The results are shown in Table 2.

Evaluation of image blur and flow: 0: There is no blur or flow in the image, and there is no deterioration in image quality at all.

Slight blurring and flow are observed in the 62 image.

×2 There is blur and flow in the image, and the deterioration in image quality is clearly seen.

As is clear from Table 1, the surface potential at the time of charging, that is, the initial surface potential, and the surface potential-exposure characteristic, that is, It can be seen that the repetition stability of electrostatic properties such as gradation properties is excellent. Furthermore, among the photoreceptors shown here, a-
It can also be seen that the si (amorphous silicon) photoreceptor has excellent repeated stability of electrostatic properties.

Furthermore, as is clear from Table 2, the inventive example using a nonwoven fabric having a layer containing natural fibers as a main component exhibited superior resolution and no decrease in resolution compared to the comparative example using a nonwoven fabric. unacceptable. In addition, there is little blurring or blurring of the image, and there is very little image deterioration.In particular, when the nonwoven fabric made of natural fibers is in direct contact with the photoconductor of the photoreceptor drum, there is no image deterioration and the image is extremely good.

Although the cleaning device according to the present invention has been described above, the present invention is not limited thereto.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

<Effects of the Invention> As described in detail above, according to the present invention, adherents such as toner, dirt, and dust remaining after the toner image formed on the photoconductor is transferred are removed by uniformly applying an appropriate amount of cleaning liquid. By moving and wiping with a nonwoven fabric impregnated with natural fibers, the deposits are blended with the cleaning solution and effectively removed without damaging the surface of the photoconductor. It is possible to stably obtain high quality, high gradation continuous tone images.

Further, according to the present invention, the electrical properties of the photoconductor are not deteriorated during cleaning, and the repeatability of electrostatic properties such as the initial surface potential and gradation properties of the photoconductor after cleaning can be improved. , it is possible to stably obtain high-quality, high-gradation, continuous-tone images without deterioration in resolution and without image deterioration such as image blurring or blurring.

Further, the present invention is applicable to both monochrome and color image recording.

[Brief explanation of the drawing]

FIGS. 1a, 1b, and 1c are cross-sectional views showing examples of the structure of a nonwoven fabric having a layer mainly composed of natural fibers used in the cleaning method according to the present invention. FIG. 2 is a schematic diagram showing an example of an electrophotographic printer using an apparatus for carrying out the cleaning method according to the present invention. FIG. 3 is a partially cutaway perspective view showing one embodiment of a press roll of an apparatus for carrying out the cleaning method according to the present invention. FIG. 4 is a view taken along the line III-III in FIG. 2. FIG. 5 is a sectional view of another embodiment of a pressure roll of an apparatus for carrying out the cleaning method according to the invention. FIG. 6 is a view taken along the line V-V in FIG. 4. FIG. 7 is a schematic diagram of a conventional cleaning device. FIG. 8 is a graph of a gradation characteristic curve normalized by the surface potential before exposure. Explanation of symbols 1... Adhesive surface, 2... Transparent image receiving sheet, 3... Release paper or release film (ML type sheet), 4
...Support, 6.Layer mainly composed of natural fibers, 7.Back fiber layer, 8.Surface fiber layer, 10.Photoconductor, 11.Photoreceptor drum. ,
12... Charger, 13... Exposure section, 14...
- Wet type developer, 15a... squeeze roller, 15b... blade, 16.57... drum drying fan 17... adhesive transfer means, 18... static eliminator, 20... cleaning device, 21...Erasing lamp, 22...Laser light source, 23...Light beam, 24...Light modulator, 25...Modulation circuit, 236...Light deflector, 27...Scanning lens , 28... Image signal supply device, 29a... Correction table, 29b... A/D converter, 30... Transfer roller, 31... Image receiving sheet supply roller, 32A, 32B... Nip roller , 33... Release sheet winding roller, 40A, 40B... Pressure roller, 50... Nonwoven fabric, 51... Supply roll, 52... Winding roll, 54... Press roll, 55 ...Guide roll, 56.56...Nip roll, 58...Hollow part, 60...Capillary tube, 61.62...Roll shaft, 63...Bearing, 65...Through hole, 66 ...Liquid sending vibrator, 6F...rod material, F...liquid developer, S...color image signal, CL...cleaning liquid patent applicant Fuji Photo Film Co., Ltd. agent
Person Patent Attorney Minoru Watanabe U G, 1a G, lb 3.3 1G, 4 F 1G, 5 6.6 1G, 7

Claims (1)

[Claims] (1) Before forming an electrostatic latent image on the photoconductor disposed on the outer peripheral surface of the photoreceptor drum, a nonwoven fabric having a layer mainly composed of natural fibers is impregnated with a cleaning liquid, and the nonwoven fabric is exposed to the light. A cleaning method characterized in that the surface of the photoconductor is cleaned by moving the photoconductor while making contact with the conductor.