JPH04457A - Electrophotographic image forming device - Google Patents

Abstract

PURPOSE:To correct the irregularity of the characteristic of a photosensitive body and to form a uniform and stable image by storing the characteristic information of the photosensitive body and adjusting a toner adhering quantity on the surface of the photosnesitive body based on the stored information. CONSTITUTION:The surface potential of the photosensitive body 34A by a corona charger 35 is detected by a surface potential sensor 32, and the electro static charging characteristic and the dark attenuation characteristic at the respective points of the photosensitive body 34A are calculated by a host com puter 22 to store in a memory 15. After performing discharge and radiating a specified quantity of light from an LED array 11, the above processing is performed in the same manner and light sensitivity characteristic is stored in the memory 15. After black and three colors images are successively formed on the photosensitive body 34A, they are transferred. In such a case, the com puter 22 controls the discharge voltage of the charger 35, the light quantity of the array 11, the light intensity of a laser beam from a laser 12 and the bias voltage of a developing roller based on the photosensitive body characteris tic information stored in the memory 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic image forming apparatus that forms an electrostatic latent image on the surface of a photoreceptor and forms a toner image using this electrostatic latent image.

[Prior art]

Conventionally, electrophotographic image forming apparatuses have been applied to many copying machines, printers, etc. due to their simplicity, high speed, and low cost. In particular, wet-type electrophotographic image forming apparatuses have higher resolution than dry-type electrophotographic image forming apparatuses, and are therefore known to be suitable for electrophotographic image forming apparatuses that require high image quality.

In addition, when applying the above-mentioned wet electrophotographic image forming apparatus to fields that require extremely high image quality, such as commercial printing proofs, it is necessary to produce uniform and stable static images over a large area of at least A3 size or larger. It is necessary to form an electrolatent image and a toner image.

[Problem to be solved by the invention]

However, in the photoreceptor used in the electrophotographic image forming apparatus, it is difficult to make the photoreceptor characteristics such as charging characteristics, dark decay characteristics, and photosensitivity characteristics uniform at each point on the surface of the photoreceptor due to manufacturing technology. The problem is that the thickness of the photoreceptor varies slightly, making it extremely difficult. In addition, this unevenness in photoreceptor characteristics can be corrected by conventional methods such as correction of variations in charging voltage, exposure light amount, etc. for each electrophotographic image forming apparatus, and charging voltage, exposure light amount, etc. in response to environmental changes (temperature fluctuations and humidity fluctuations). There is a problem that the above correction does not improve the problem.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide an electrophotographic image forming apparatus that can correct unevenness in the characteristics of a photoreceptor and form a uniform and stable image.

[Means to solve the problem]

An electrophotographic image forming apparatus according to the present invention is an electrophotographic image forming apparatus that forms an electrostatic latent image on the surface of a photoreceptor and forms a toner image using the electrostatic latent image, the a storage means that stores photoreceptor characteristic information such as charging characteristics, dark decay characteristics, and photosensitivity characteristics; The amount of toner adhering to the surface of the photoreceptor is adjusted by correcting one of the surface potential of the photoreceptor surface, the amount of light irradiation for forming the electrostatic latent image, or the developing bias voltage applied during development. It is characterized by being equipped with an image forming means.

[Effect]

According to the above means, when an electrostatic latent image is formed on the surface of the photoreceptor and a toner image is formed using this electrostatic latent image, the image forming means can perform each of the steps on the surface of the photoreceptor stored in advance in the storage means. The output is varied based on photoreceptor characteristic information such as charging characteristics, dark decay characteristics, and photosensitivity characteristics at a point. As a result, at least one of the surface potential of the photoconductor surface, the amount of light irradiation for forming an electrostatic latent image, or the development bias voltage applied during development is corrected, and the amount of toner adhering to the photoconductor surface is adjusted. .

Therefore, the toner image formed on the surface of the photoreceptor can be uniform and stable because the uneven characteristics of the photoreceptor are corrected.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a layout diagram of each processing section constituting a wet-type electrophotographic image forming apparatus as an electrophotographic image forming apparatus according to an embodiment of the present invention.

Exposure section 10 forming part of a wet electrophotographic image forming apparatus
is connected to a semiconductor laser 12, a control unit 14 for controlling the output state of the semiconductor laser 12, a condenser lens 16.26, a scanning lens 28, a reflection mirror 24.30, and a buffer 19, and receives the incident laser beam. It records image information supplied from a multi-AOM (acousto-optic modulator) 18 that divides the ultrasonic wave into multiple parts according to the frequency, a polygon mirror 20, and a host computer 22, and also records the image information on the outer peripheral surface of a photosensitive drum 34, which will be described later. It is constituted by a memory 15 that stores photoreceptor characteristic information such as charging characteristics, dark decay characteristics, and photosensitivity characteristics at each point on the body 34A.

As the semiconductor laser 12, for example, Al-Ga-A
s laser can be used. A laser beam emitted from the semiconductor laser 12 is irradiated onto the multi-AOM 18 via a condensing lens 16. Further, ultrasonic waves of different frequencies generated according to the image information stored in the memory 15 are supplied to the multi-A○M 18. This causes the laser beam to be diffracted in different directions depending on the frequency of the ultrasound.

Further, the light intensity of the laser beam is modulated by the multi-AOM 18 according to information on the photoreceptor characteristics (photosensitivity characteristics) of the photoreceptor 34A stored in the memory 15. Therefore, by modulating this laser beam, unevenness in the photosensitivity characteristics of the photoreceptor 34A is corrected.

This laser beam is condensed by a condensing lens 26, and is further incident on a polygon mirror 20 rotating at high speed via a reflection mirror 24. The laser beam reflected by the polygon mirror 20 is sent to the scanning lens 28 and the reflection mirror 3.
0 to the image forming area on the surface of the photosensitive drum 34. In this embodiment, since a multi-AOM is used, a plurality of (eg, eight) laser beams are scanned simultaneously.

The photosensitive drum 34 is connected to a drive means (not shown), and is rotated clockwise in FIG. 1 (in the six directions of arrows in FIG. 1) by this drive means. Further, the rotation angle of the photosensitive drum 340 (the rotational position of the photosensitive drum 34 from the home position) is detected by a well-known photosensitive drum rotational position detection device, and is manually input to the host computer 22 at any time.

A photoreceptor 34A is provided on the outer peripheral surface of the photoreceptor drum 34 made of aluminum. As the photoreceptor 34, a well-known organic photoconductor or inorganic photoconductor can be used.

It is also possible to use a dielectric material charged with a charging needle.

Organic photoconductors include a variety of well-known organic photoconductors. Specifically, “Research Disclosure J
(Research Disclosure) Magazine #10
938 (May 1973 issue, page 61 et seq., an article entitled "Electrophotographic Elements, Materials and Processes").

For example, polyN-vinylcarbazole and 2.4.7-) are in practical use. Electrophotographic photoreceptor consisting of J nitrofluorene-9-one (US Pat. No. 3,48
4,237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 48-2565
8), an electrophotographic photoreceptor containing an organic pigment as a main component (Japanese Patent Application Laid-Open No. 4937543), an electrophotographic photoreceptor containing a eutectic complex consisting of a dye and a resin as a main component (Japanese Patent Application Laid-Open No. 47-10735)
No.), an electrophotographic photoreceptor in which copper phthalocyanine is dispersed in a resin (Japanese Patent Publication No. 1667/1983), and the like. Others, Journal of the Society of Electrophotography, Vol. 25, No. 3 (1986), 62-
There are substances listed on page 76.

Further, as the inorganic photoconductor used in the present invention, "Electro Photography J (rElectr.

photography J R, M, 5chaffe
Typical examples include various inorganic compounds such as those disclosed in ``Mr. Rt., Focal Press (London) Publishing'' (1975), pp. 260-374.Specific examples include zinc oxide, zinc sulfide, cadmium sulfide, and selenium. , selenium-tellurium alloy, selenium-arsenic alloy, selenium-tellurium-arsenic alloy, and the like.

In addition, amorphous silicon can also be used. This amorphous silicon has fast dark decay but can be used repeatedly, so it is suitable for this embodiment.

A corona charger 35 as part of the image forming means is disposed upstream in the rotational direction of the photoreceptor at a position where the laser beam is incident on the photoreceptor 34A. This corona charger 35 includes a corona wire and a grid wire, and is connected to AC and DC power sources via a changeover switch (not shown). Further, the corona charger 35 is connected to the host computer 22 that constitutes a part of the image forming means.
The discharge voltage is controlled based on the photoreceptor characteristics (charging characteristics, dark decay characteristics) information stored in the memory 15, and the unevenness of the photoreceptor characteristics in the rotational direction of the photoreceptor 34A is corrected.

As a result, the photosensitive drum 34 before electrostatic latent image formation is rotated clockwise in FIG. 1 after the surface of the photosensitive member 34A is positively or negatively charged by the corona charger 35.

Further, as will be described later, by connecting the corona charger 35 to a DC power source and applying a charge having the same polarity as the toner through DC corona discharge, the charge on the toner can be strengthened (precharge).

Further, as will be described later, by connecting the corona charger 35 to an AC power source and performing AC corona discharge, the photoreceptor 34A
The charges on the photoreceptor are neutralized, and the residual potential on the photoreceptor can be removed (static charge removal).

A plurality of surface potential sensors 32 are arranged in parallel in the axial direction of the photosensitive drum 34 on the downstream side of the corona charger 35 (on the rotational direction side of the photosensitive drum 34). The surface potential at each point on the photosensitive drum 34A on the outer peripheral surface of the photosensitive drum 34 (different points in the axial direction and rotational direction of the photosensitive drum 34) can be detected, and the surface potential detected by the surface potential sensor 32 is Based on this, the host computer 22
The photoreceptor characteristic information of charging characteristics, dark decay characteristics, and photosensitivity characteristics at each point on the photoreceptor 34A is calculated, and the information is stored in the memory 1.
5 is stored in memory.

The part of the photoconductor 34A where the laser beam is incident becomes conductive and the charge on the surface disappears, causing the photoconductor 34A to become conductive.
An electrostatic latent image is formed on the surface of 4A.

As shown in FIG. 1, an LED array 11 as part of the image forming means is arranged downstream of the surface potential sensor 32 (on the rotational direction side of the photosensitive drum 34).

As shown in FIG. 2, this LED array 11 is arranged along the axial direction of the photosensitive drum 34 (left-right direction in FIG. 2).
A plurality of (light emitting diodes) 11A are arranged in parallel.

As shown in FIG. 1, the LED array 11 is connected to a host computer 22 forming part of the image forming means. Therefore, the photoreceptor characteristics (charging characteristics, dark decay characteristics) stored in the memory 15 by the host computer 22
The amount of light emitted from each LED IIA is adjusted based on the information.

As a result, as shown in FIG. 3, the corona charger 35
The amount of light (El) that corrects the unevenness of the potential distribution (El) in the axial direction of the surface potential of the photoreceptor 34 charged by
L) is irradiated from the LED array 11 under the control of the host computer 22, and the unevenness of the axial potential distribution (El) of the surface potential of the photoreceptor 340 is corrected by the irradiated light from the LED array 11. , photoreceptor 3
The axial potential distribution of the surface potential of No. 4 is uniform (E2).

Furthermore, by irradiating the photoreceptor 34A with light from the LED array 11, the electric charge on the photoreceptor 34A can be neutralized (photostatic charge removal). This optical static elimination is carried out by the corona charger 35.
In addition to exhibiting a function similar to that of static elimination, it is also possible to perform pre-exposure to improve the transfer efficiency of the toner attached to the photoreceptor 34A, as will be described later.

As shown in FIG.
A plurality of light amount sensors 33 are arranged in parallel in the axial direction of the photosensitive drum 34 at a position where the light is incident on the photosensitive drum 34.
The light amount sensor 33 is capable of detecting the amount of laser beam incident on the photoreceptor 34A on the outer peripheral surface of the photosensitive drum 34. Further, this light amount sensor 33 is connected to the host computer 22, and the light amount of the laser beam detected by the light amount sensor 33 is fed back to the host computer 22, thereby ensuring the light amount control of the laser beam.

As shown in FIG.
A pre-wet device 50 is provided downstream of the position where the light is incident (on the rotational direction side of the photosensitive drum 34 with respect to the incident position). This pre-wetting device 50 is adapted to apply a carrier liquid, which is a dispersion medium for liquid developer, for the purpose of preventing toner from adhering to non-image areas and improving transferability of toner images onto a transfer material.

A developer unit 36 as a part of image forming means is arranged downstream of the pre-wet device 50 (on the rotational direction side of the photosensitive drum 34). The developer unit 36 includes a box with an open top, and a liquid developer 38 is housed in the box. This liquid developer 38 has four types of toner particle colors: blank, yellow, magenta, and cyan. As this liquid developer 38, a known developer can be used, for example,
5-551L Special Publication Show 35-13424, Special Publication No. 50-4
0017, Special Publication No. 49-98634, Special Publication No. 58-12
9438, JP 61-180248, Fundamentals and Applications of Electrophotography Technology (Electrophotography Technology Edition, Coronasha (1988))
Examples include the developer disclosed in, et al.

These liquid developers generally include a carrier liquid, a colorant that forms toner particles, a coating agent made of a polymeric resin that provides fixation properties for the colorant, and a coating agent that promotes the dispersion of toner particles and works to stabilize the dispersion. It consists of a dispersant to control the polarity and charge amount of the toner particles, and a charge control agent to control the polarity and charge amount of the toner particles.

As the coating agent, various known resins can be used, but in particular, Japanese Patent Application Laid-Open No. 61-180248 and Japanese Patent Application No. 63-4
1272, copolymers of ethylene and (meth)acrylic acid, copolymers of ethylene and vinyl acetate, copolymers of ethylene and ethyl acrylate, and ethylene and (meth)acrylic acid esters disclosed in Japanese Patent Application No. 63-41273. Ethylene-based copolymers such as a copolymer of , a terpolymer of ethylene/(meth)acrylic acid/(meth)acrylic acid ester are preferred. The amount of toner particles in the developer is not particularly limited, but is 0.1 to 200 g/l per 1β of the developer.

(i.e. 5 to 10,000 carrier liquid per toner particle)
cc. ) As the charge control agent, various known ones can be used, and the weight concentration thereof is 0.501 to 10 g per developer 11.
, preferably 0.01 to 1 g.

Further, various known dispersants can be used, and the weight concentration thereof is preferably 0.01 to 50 g per developer II2, preferably 0.1 to 10 g.

A plurality of developing rollers 40 are arranged in the developer unit 36 and extend in the axial direction of the photosensitive drum 34 and correspond to the image forming area of the photosensitive member 34A. This developing roller 4
A part of the outer circumferential surface of 0 is immersed in liquid developer 38.

These developing rollers 40 are rotated by a drive mechanism (not shown).

The developing roller 40 also has a developing bias voltage controller 4.
It is connected to 0A, and a developing bias voltage is applied. This developing bias voltage controller 4OA is connected to a host computer 22 that constitutes a part of the image forming means, and the developing bias voltage is controlled by the host computer 22 based on the photoreceptor characteristic information stored in the memory 15. The amount of toner adhesion along the rotational direction of the photosensitive drum 34 is corrected so as not to be affected by the unevenness of the photosensitive characteristics of the photosensitive member 34A.

Further, the developing roller 40 is moved by a mechanism (not shown) from a position where the developing roller 40 is away from the image forming area to a position where it contacts the image forming area (see FIG. 1), and the liquid developer 38 is moved through the developing roller 4O. It is designed so that it can be applied to the image forming area. Further, the developing roller 40 is moved from the contact state to a state away from the image forming area by a mechanism not shown. By changing the type of developer unit 36 through this movement, four types of coloring can be achieved.

A squeeze device 41 having an air jet section 41A extending in the axial direction of the photosensitive drum 34 and facing the image forming area is disposed on the side of the developer unit 36 in the rotational direction of the photosensitive drum 34. The excess liquid developer 38 supplied to the tank is removed and discharged to a waste liquid tank.

On the downstream side of the squeeze device 41 in the rotational direction of the photosensitive drum 340, there is a squeeze device 4 extending in the axial direction of the photosensitive drum 34.
3 is placed. The squeeze device 43 has an air jet section 4.
3A is formed, and a liquid developer discharge path 43B and a rinse liquid discharge path 43C are formed with this air jet portion 43A sandwiched therebetween.

These air jetting portions 43A, liquid developer discharge passages 43B,
A liquid outlet path 43C extends in the axial direction of the photosensitive drum 34 and faces the image forming area. The liquid developer discharge path 43B and the rinse liquid discharge path 43C are connected to a waste liquid tank (not shown), and the air jetted from the air jet section 43A is blown onto the excess liquid developer and rinse liquid attached to the photoreceptor 34A. The liquid developer and the rinsing liquid are discharged to the waste liquid tank via the liquid developer discharge path 43B and the rinse liquid discharge path 43C, respectively.

A rinse liquid unit 42 is arranged downstream of the squeeze device 43 in the rotational direction of the photosensitive drum 34 . The rinsing liquid unit 42 includes a box with an open top. A rinsing liquid 44 is contained in this box. The rinsing liquid 44 has an electrical resistance of I x 109 Ω・
A non-polar non-aqueous solvent having a dielectric constant of 3 cm or more and a dielectric constant of 3 or less can be used.

Examples of the non-aqueous solvent include solvents such as linear or branched aliphatic hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbons, but there are concerns regarding volatility, safety, odor, etc. In terms of octane, isooctane, decane,
Isopar E1 Isopar G, Fisovar H1 Isopar L (Isopar RLSO
perJ is the product name of Exxon), Tsurpets 1001
Siel Silua 1 (manufactured by Shell) and the like are suitable.

A plurality of rinse rollers 46 are arranged in the rinse liquid unit 42 so as to face the image forming area and extend in the axial direction of the photosensitive drum 34 . A portion of the outer peripheral surface of this rinse roller 46 is immersed in the rinse liquid 44. The rinse roller 46 is connected to the rinse roller 4 by a mechanism (not shown).
6 is moved from a position away from the image forming area to a position in contact with the image forming area shown in FIG.
can be applied to the image forming area via a rinse roller 46.

Further, the rinse roller 46 is moved from the contact state to a state away from the image forming area by a mechanism not shown. Further, the rinse roller 46 is brought into contact with the image forming area during development processing and is moved away from the image forming area by a mechanism not shown.

A squeeze device 62 is disposed downstream of the rinsing liquid unit 42 (on the rotational direction side of the photosensitive drum 34) and has an air jetting section 62A that extends in the axial direction of the photosensitive drum 34 and faces the image forming area. The rinsing liquid supplied to the image forming area is removed from the image forming area by the air jetted from the air jetting section a 62A, and is led to the developing unit through a waste path (not shown).

An exhaust duct 66 that constitutes a part of the drying processing section 64 is arranged downstream of the squeeze device 62 (on the rotational direction side of the photosensitive drum 34). The exhaust duct 66 has an arc-shaped opening 66B having substantially the same radius of curvature as the photoreceptor 34A on the side facing the photoreceptor 34A.

Further, on the downstream side of the exhaust duct 66 in the drum rotation direction, there is an intake chamber 6 that constitutes the drying processing section 64 together with the exhaust duct 66.
8 is placed.

The side of this intake chamber 68 opposite to the photosensitive drum 34 is connected to a blower (not shown), and the side of the photosensitive drum 34 is connected to an exhaust duct 66.
It faces the air inlet opening 66A on the downstream side. Air sent through the air inlet opening 66A (arrow W in FIG. 1) passes through the opening 66B and is blown onto the photoreceptor 34A, thereby drying the wet photoreceptor 34A.

The air sent to the photoreceptor 34 is discharged to the outside of the apparatus via the air discharge port 66C.

A transfer unit 70 is arranged downstream of the intake chamber 68 (on the rotational direction side of the photosensitive drum 34). The transfer section 70 is moved toward and away from the outer periphery of the photoreceptor 34A by a drive mechanism (not shown). A pair of transfer rollers 72 extending in the axial direction of the photosensitive drum 34 are provided in the transfer section 70 in close proximity to the photosensitive member 34A. A transfer guide 74 extending in a direction away from the photosensitive drum 34 is arranged above the transfer rollers 72 . A tray 75 for storing a transfer material is connected to the transfer guide 74, and the transfer material set on the tray 75 is guided by the transfer guide 74 and placed between the transfer roller 72 and the photoreceptor 34A. The transcription is then carried out.

A cleaning section 76 is arranged downstream of the transfer roller 72 (on the rotational direction side of the photosensitive drum 34), and on the downstream side of the cleaning section 76 (on the rotational direction side of the photosensitive drum 34).
A cleaning brush 77 is arranged. The cleaning section 76 is equipped with a take-up roller 78 and a web roller 79. A cleaning web 82 made of nonwoven fabric or the like is wound around the take-up roller 78 and the sea urchin flora 79.

Further, the cleaning section 76 is provided with a cleaning roller 84 having a plurality of through holes 84A formed therein so as to extend in the axial direction of the photosensitive drum 34.

This cleaning roller 84 has the above-mentioned isopar G.
Contains a carrier liquid such as This cleaning roller 84 is wound around the middle part of the cleaning web 82. The cleaning roller 84 faces the image forming area via the cleaning web 82. The cleaning unit 76 is moved by a drive mechanism (not shown) in a direction such that it comes into contact with and separates from the outer peripheral surface of the photoreceptor 34A.

In the cleaning process, the cleaning roller 84 is driven by the mechanism described above to a position close to the photoreceptor 34A, and the cleaning web 82 comes into contact with the photoreceptor 34A. The cleaning web 82 is also wound clockwise by the take-up roller 78. The cleaning roller 84 is rotated clockwise following the winding operation, and with this rotation, the carrier liquid flows out from the through hole 84A, and the portion of the cleaning web 82 penetrated by the carrier liquid is attached to the photoreceptor 34A. By sliding along the surface, residual toner etc. after transfer are removed.

A cleaning brush 77 is arranged downstream of the cleaning section 76 (on the rotational direction side of the photosensitive drum 340). The cleaning brush 77 is constructed by planting a large number of animal hairs on the cylindrical surface of a cylindrical body, extends in the axial direction of the photosensitive drum 34, and is brought into contact with the outer circumferential surface of the photosensitive member 34A by a drive mechanism (not shown). Be turned away. In the cleaning process to be described later, the cleaning brush 77 touches the photoreceptor 34.
A is slid along the surface of the photoreceptor 34A to remove foreign matter attached to the photoreceptor 34A without disturbing the toner image formed on the photoreceptor 34A.

The operation of this embodiment will be explained below.

In this embodiment, the corona charger 35 discharges the photoreceptor 34A at a constant voltage, and after a predetermined period of time, the surface potential sensor 32 detects each point on the photoreceptor 34A (photoreceptor 34A).
Detects the surface potential at different points in the axial and rotational directions. Based on the surface potential thus detected, the host computer 22 calculates the charging characteristics and dark decay characteristics at each point on the photoreceptor 34A, and
It is designed to be memorized.

In addition, the corona charger 35 discharges the photoreceptor 34A with a constant voltage, and the LED array 11 irradiates the photoreceptor 34A with a predetermined amount of light. The surface potential at each point on the photosensitive drum 34A (different points in the axial direction and rotational direction of the photosensitive drum 34) is detected. Based on the surface potential thus detected, the host computer 22 controls the photoreceptor 3.
Calculate the photosensitivity characteristics for each point on 4A, and store it in memory 1.
5 is stored in memory.

Alternatively, before installing the photosensitive drum 34 into the present apparatus, the surface potential and dark decay characteristics at each point on the photosensitive drum 34A (different points in the axial direction and rotational direction of the photosensitive drum 34) are evaluated using another dedicated evaluation device. Electrophotographic characteristics such as photosensitivity characteristics and residual potential may be measured and the data may be stored in Memo 'J-15.

The following processing is performed based on the photoreceptor characteristic information stored in the memory 15.

In this embodiment, after a black image is formed, yellow, magenta, and cyan images are formed superimposed on the black image. Further, in this embodiment, a developer containing negatively charged toner particles is used.

First, a case will be described in which a black image is formed on the photoreceptor 34A. Image information of the image to be copied is supplied from the host computer 22.

When a transfer start switch (not shown) is turned on, the photosensitive drum 34 is rotated clockwise in FIG. 1 by a driving means (not shown), the corona charger 35 is activated, and
C. The photoreceptor 34A is positively charged by corona discharge (Charging in FIG. 4(A)). In this case, the corona charger 35
The discharge voltage is controlled by the host computer 22 based on the photoreceptor characteristics (charging characteristics, dark decay characteristics) information stored in the memory 15, and the unevenness of the photoreceptor characteristics in the rotational direction of the photoreceptor 34A is corrected.

Next, the photoreceptor 34A is exposed to light by the LED array 11. The light intensity of this LED array 11 is determined by the photoreceptor characteristics (
Charging characteristics, dark decay characteristics) are adjusted based on information.

As a result, as shown in FIG. 3, the corona charger 35
The amount of light (El) that corrects the unevenness of the potential distribution (El) in the axial direction of the surface potential of the photoreceptor 34 charged by
L) is irradiated from the LED array 11 under the control of the host computer 22, and the axial potential distribution of the surface potential of the photoreceptor 34 (
The unevenness of El) is corrected, and the potential distribution of the surface potential of the photoreceptor 34 in the axial direction becomes uniform (E2).

Note that the potential distribution (E3) in FIG. 3 is the potential distribution in the axial direction of the surface potential of the photoreceptor 34, taking into consideration the potential decrease due to dark decay.

When the image forming portion of the photoreceptor 34A, whose surface is approximately uniformly positively charged, is located at the exposure position, the laser beam irradiated from the semiconductor laser 12 is modulated according to the image information, so that the photoreceptor 34A forms an image. exposed (fourth
Figure (A) Exposure).

In this case, the light intensity of the laser beam is modulated by the host computer 22 via the multi-AOMI 8 according to information on the photoreceptor characteristics (light sensitivity characteristics) of the photoreceptor 34A stored in the memory 15. Therefore, by modulating this laser beam, unevenness in the photosensitivity characteristics of the photoreceptor 34A is corrected.

When the surface of the photoreceptor 34A is imagewise exposed, the portion irradiated with the laser beam becomes conductive, and the positive charges on the surface move to form an electrostatic latent image corresponding to image information.

The photoreceptor 34A, on which the electrostatic latent image is formed, is further
The photoreceptor 3 is rotated clockwise in the figure, and the pre-wet device 50
The carrier liquid is uniformly applied to the surface of 4A.

The pre-wet portion of the photoreceptor 34A further rotates clockwise in FIG. 1 and reaches a position corresponding to the developer unit 36. In this case, a developer unit 36 containing a liquid developer containing black toner particles is arranged in advance. This developer unit 36 applies a liquid developer containing black toner particles to the area where the electrostatic latent image is formed via a developing roller 40 (FIG. 4(A) development).

In this case, the bias voltage of the developing roller 40 is controlled by the host computer 22 connected to the developing bias voltage controller 40A based on information on photoreceptor characteristics (particularly dark decay characteristics) stored in the memory 15, and Correct the unevenness of residual potential.

As a result, negatively charged toner particles in the developer adhere to the image area where the electrostatic latent image is formed, and the electrostatic latent image is visualized, and the photoreceptor corresponding to the image area or non-image area is The characteristic unevenness of 34A is corrected, and a uniform and stable toner image is formed (FIG. 5(A)).

The portion of the photoreceptor 34A on which the toner image is formed further rotates clockwise in FIG. 1 and reaches a position corresponding to the squeeze device 41. The area where the toner image is formed is squeezed by being blown with air from the air jetting section 41A, thereby guiding the excess liquid developer 38 to a tank (not shown) (FIG. 4(A) Squeeze 1).

The portion of the photoreceptor 34 on which the toner image is formed further rotates clockwise in FIG. 1 and reaches a position corresponding to the rinse liquid unit 42 filled with the rinse liquid 44. Photoreceptor 44
A rinsing liquid 44 is supplied to the surface of the photoconductor 34A via a rinsing roller 46, and the developer containing unnecessary toner particles adhering to the portions of the photoreceptor 34A other than the image area to which the toner should adhere is washed away (see FIG. 4). A) Rinse).

The excess rinsing liquid 44 supplied to the photoconductor 34A is flowed downstream along the outer peripheral surface of the photoconductor 34A, but is removed from the surface of the photoconductor 34A by air jetted from the air jet section 43A of the squeeze device 42. and the discharge path 43C
is discharged to a waste liquid tank (not shown) via the
A) Squeeze 2).

The photoreceptor 34A further rotates clockwise in FIG. 1 and faces the opening 66A of the exhaust duct 66.

From this frontage 1ff166A, dry air supplied from a blower (not shown) is blown onto the surface of the photoreceptor 34A. This dry air makes the photoreceptor 3 moist.
The surface of 4A is dried (FIG. 4(A) drying).

From this state, the photoreceptor 34A is further rotated clockwise in FIG. 1, and the photoreceptor 34A shifts to the second rotation. In this second round, only the drying process is performed (Fig. 4 (B)
dry).

As a result of this drying, the rinsing liquid and carrier liquid present between the toner particles forming the electrostatic latent image evaporate, increasing the interaction (bonding force) between the toner particles.
As the photoreceptor 34A rotates around the circumference, the portions of the photoreceptor 34A that face the corona charger 35 are charge-removed by AC corona discharge by the corona charger 35 (FIG. 4(C) charge removal).

Furthermore, the light emitted from the LED array 11 is supplied to this charge-eliminated portion, and the charge remaining on the dust light body 34A after the charge removal is removed (FIG. 4(C) optical charge removal). Thereafter, the drying process is continued until the third rotation is completed.

Next, the process moves on to the image forming process of the second color (yellow) (
4 same mouth). In this second color application process, first, the cleaning brush 77 is moved onto the photoreceptor 3 by a drive mechanism (not shown).
The foreign matter attached to the photoreceptor 34A is removed by sliding along the surface of the photoreceptor 4A (FIG. 4(D) puff). As the photoreceptor 34A rotates, the portion of the photoreceptor 34A from which the foreign matter has been removed is sequentially charged (charging in FIG. 4(D)) and exposed (exposure in FIG. 4(D)) in the same manner as described above. , an electrostatic latent image is formed on the photoreceptor 34A.

The area on the photoconductor 34A where the electrostatic latent image is formed is pre-wet (pre-wet in FIG. 4(D)) before the development process in the same way as described above, to prevent toner particles from adhering to the non-image area. After that, the development is performed, and a toner image of yellow toner particles is formed on the photoreceptor 34A, superimposed on the toner image formed of the blank toner particles (FIG. 4(D) Development, Figure 5 (B)). At this time, the developer unit 36 is moved so that the unit containing the developer containing yellow toner comes into contact with the surface of the photoreceptor 34A. After that, the same squeeze 1 (Fig. 4 (D) squeeze 1), rinsing (Fig. 4 (D) rinse), squeeze 2 (Fig. 4 (D) squeeze) and drying treatment (Fig. 4 (D)) as described above are carried out. D) drying) is performed.

Next, similar to the step of applying the first color toner particles, drying is performed during the rotation of the fifth circumference of the photoreceptor 34A (
(Drying in FIG. 4(E)), static elimination (Charging in FIG. 4(F)), light exposure (Light exposure in FIG. 4(F)), and drying are further carried out in the sixth same port.

In the same way as applying the second color liquid developer, apply the third color (
A liquid developer containing toner particles of magenta is applied. As a result, a toner image of magenta toner particles is formed on the photoreceptor 34A, superimposed on the toner image formed of the yellow toner particles. As a result, three toner layers of black, yellow, and magenta toner particles are formed on the photoreceptor 34A (FIG. 5(C)).

When applying the fourth color (cyan), that is, the final color, use a puff (removal of foreign matter with a cleaning brush) (see Figure 4) in the same way as when applying the second and third colors. (G) puff), charging (Fig. 4 (G) charging), exposure (Fig. 4)
After performing pre-wetting (Fig. 4 (G) Pre-wet) and preventing toner particles from adhering to non-image areas, development (Fig. 4 (G) Development) is performed. A toner image of cyan toner particles is formed on the photoreceptor 34A, superimposed on the toner image formed of the magenta toner particles.

As a result, toner layers of four colors, black, yellow, magenta, and cyan, are formed on the photoreceptor 34A. After that, the same squeeze 1 as above (Figure 4 (G) squeeze 1)
, rinsing (Fig. 4 (G) Rinse), squeeze 2 (Fig. 4 (G) Squeeze 2), and drying (Fig. 4 (G) Drying). The above operations are performed while the photosensitive drum 34A rotates once. The drying process is performed during the period in which the photoreceptor 34A is further rotated once in the clockwise direction in FIG. 1 (Drying in FIG. 4(H)). This second and final color rotation is only for drying.

The photoreceptor 34A is further rotated and moves to the third rotation. In this third rotation, first the corona charger 35
An electric charge having the same polarity as that of the toner is applied to the photoconductor 34A by DC corona discharge caused by the DC corona discharge.
precharge) is performed.

The portion of the photoreceptor 34A that is not precharged is further
It rotates clockwise in the figure and reaches a position corresponding to the LED array 11. The light emitted from the LED array 11 is transmitted to the photoreceptor 3.
4A for pre-exposure.

The pre-exposed portion of the photoreceptor 34A further rotates clockwise in FIG. 1 and reaches a position corresponding to the briwet device 50. As described above, the droplet-shaped carrier liquid is ejected from the briwetting device 50 and applied to the pre-exposed area, thereby performing briwetting before transfer.

On the other hand, the transfer material guided by the guide 74 to a position where it is sandwiched between the photoreceptor 34A and the roller 72 is sandwiched by the portion of the photoreceptor 34A where the toner particle layers of the four colors are formed, and is A transferred image is formed using the toner layer (FIG. 5(D)). As a result, an original image is formed on the surface of the transfer material.

Further, the photosensitive drum 34A is rotated clockwise in FIG. 1 to proceed to a cleaning process. In this cleaning step, web cleaning is performed and further drying processing is performed to bring the photoreceptor to the initial state before exposure as shown in FIG. 4(A).

Although negatively charged toner particles are used in the above example, positively charged toner particles may also be used. In this case, the photoreceptor 34A is negatively charged.

Further, in the above embodiment, the photoreceptor 34 is stored in the memory 15.
Although each photoconductor characteristic information such as charging characteristics, dark decay characteristics, and photosensitivity characteristics at each point of A is stored, in addition to these photoconductor characteristic information, environmental fluctuations such as temperature and humidity at each point of the photoconductor 34A are stored. The photoreceptor characteristic information related to this is stored in the memory 15, and the corona charger 35 is
It is also possible to control image forming means such as the following. Thereby, a more uniform and stable image can be formed.

Further, in the above embodiment, based on the photoconductor characteristic information at each point of the photoconductor 34A stored in the memory 15, the host computer 22 controls the LED array 11, the multi-AOM 18, the corona charger 35, and the developing bias voltage controller 40A. However, some of these are controlled by the host computer 22 based on the photoconductor characteristic information at each point of the photoconductor 34A stored in the memory 15, and the characteristic unevenness of the photoconductor 34A is corrected, and uniform and A stable image may be formed.

[Effects of the Invention] Since the present invention has the above-mentioned configuration, it is possible to obtain an excellent effect of correcting unevenness in the characteristics of the photoreceptor and forming a uniform and stable image.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of each processing section constituting a wet electrophotographic image forming apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of an LED array according to an embodiment of the present invention, and FIG. Surface potential distribution diagrams showing correction of surface potential by the LED array according to an embodiment of the present invention, FIGS. 4(A) to 4(J) are wet type electrophotographic image forming apparatus according to an embodiment of the present invention 5 (A> to 5 (D>) are cross-sectional views showing the process of forming four-layer images on the photoreceptor. 10... Exposure section, 11. ...LED array, 12...Semiconductor laser, 15...Memory, 18...Multi-AOM18. 22...Host computer, 34...Photosensitive drum, 34A...Photoconductor, 35... Corona charger, 36...Developer unit, 40...Developing roller, 4OA...Developing bias voltage controller.

Claims (1)

[Claims] (1) An electrophotographic image forming apparatus that forms an electrostatic latent image on the surface of a photoreceptor and forms a toner image using the electrostatic latent image, which includes charging characteristics, dark decay characteristics, and light at each point on the surface of the photoreceptor. A storage means that stores photoreceptor characteristic information such as sensitivity characteristics; and an image forming means for correcting at least one of the amount of light irradiation for forming a latent image or the developing bias voltage applied during development to adjust the amount of toner adhering to the surface of the photoreceptor. An electrophotographic image forming device.