JPH10221959A - Liquid image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid image forming device equipped with a liquid developing device capable of detecting the probability of image failure which is caused by variation in the layer thickness of liquid developer. SOLUTION: In an area of a developing roller 42 where a liquid developer 40 formed into a thin layer by a layer-thickness regulation roller 43 is supported, an optical detecting device is provided as a layer-thickness detection means for detecting the regulated layer-thickness of the liquid developer. The optical detecting device has a light emitting element 401, as a light emitting part, which emits light toward a specific detecting position which is downstream from the area where the developing roller 42 faces the layer-thickness regulation roller 43 in the direction of the rotation of the developing roller 42 but is upstream from the area where it faces a photoreceptive drum 1, and a light receiving element 402, as a light receiving part, which receives light reflected from the detecting position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
A developer support for supporting a high-concentration, high-viscosity liquid developer on the surface; and a thinning means for thinning the liquid developer on the developer support. A liquid developing device that performs a developing operation of bringing a liquid developer into contact with the surface of a latent image carrier by moving the surface of the developer support and visualizing an electrostatic latent image formed on the surface of the latent image carrier is provided. The present invention relates to a liquid image forming apparatus provided.

[0002]

2. Description of the Related Art In a liquid image forming apparatus of this type, an electrostatic latent image is formed on a photoreceptor or the like as a latent image carrier, and the electrostatic latent image is formed by a liquid developing device into a toner, which is charged particles. And develop. To reduce the size of the developing device, it has been proposed to use a high-concentration and high-viscosity developer in which the toner concentration of a developer in which toner is dispersed in an insulating liquid is increased. For example, in JP-A-7-209922,
A liquid developing method for an electrostatic latent image formed by developing an electrostatic latent image formed on an image support with a toner, which is a charged visualization particle, comprising applying the electrostatic latent image on a conductive developer support. High concentration of toner dispersed in insulating liquid
A developing step of bringing the liquid developer having a high viscosity of 0 to 10000 mPa · s into contact with the image support to supply the liquid developer to a latent image surface of the image support. Liquid development method for latent images. Has been proposed. According to the publication, the liquid developer is further added to 5 to 40
There is also disclosed a liquid developing method and a liquid developing apparatus in which the thickness is reduced to a layer thickness of μm.

[0003]

In the above publication,
Although the thickness of the layer is specified, there is no mention of the variation in the layer thickness. However, in the liquid developing apparatus having the above-described structure, the liquid developer used for development may be deficient, or the thickness of the layer-thickness regulating member that regulates the thickness of the layer on the developer support and may be reduced, and There may be a deviation from the inclination of the surface of the agent support, or the layer thickness regulating member may be deteriorated. As a result, the layer thickness of the liquid developer on the surface of the developer support may vary, or a portion where the liquid developer layer is not formed may occur.
In the developing device having the above-described structure, the thin layer of the high-density and high-viscosity liquid developer formed on the surface of the developer support is transferred onto the latent image carrier together with the layer. This causes a variation in the layer thickness of the toner image formed thereon. Therefore, when the thickness of the liquid developer thin layer formed on the developer support varies, or when a portion where the liquid developer layer is not formed occurs, the density of the image to be visualized is changed. Adverse effects such as And
When the image is transferred to a recording medium, for example, recording paper,
It is conceivable that the above-mentioned adverse effects also occur in the transferred image.

The present invention has been made in view of the above background, and an object of the present invention is to detect a possibility that an image defect may occur due to a variation in the thickness of a liquid developer layer. An object of the present invention is to provide a liquid image forming apparatus provided with a liquid developing device.

[0005]

In order to achieve the above object, the present invention is directed to a developer support having a surface on which a high-concentration and high-viscosity liquid developer is supported, and a developer support on the developer support. Thinning means for reducing the thickness of the liquid developer, contacting the thinned liquid developer with the surface of the latent image carrier by moving the surface of the developer support, In a liquid image forming apparatus provided with a liquid developing device for performing a developing operation for visualizing an electrostatic latent image formed on a surface of a carrier, a layer thickness detection for detecting a layer thickness of the thinned liquid developer A means is provided.

In this liquid image forming apparatus, the layer thickness of the thinned liquid developer is directly or indirectly detected by the layer thickness detecting means. As a result, it is possible to determine whether or not the layer thickness of the liquid developer varies or whether there is a portion where the liquid developer layer is not formed, using the detection result.

According to a second aspect of the present invention, in the liquid image forming apparatus of the first aspect, the color of the surface of the developer support is different from the color of the liquid developer, and The developer support has a light-emitting unit that emits light toward at least a part of a region that supports the thinned liquid developer, and a light-receiving unit that receives reflected light reflected on the part, An optical detection device having sensitivity only to the color of the liquid developer, wherein the layer thickness of the liquid developer on the surface of the developer support is based on a detection result by the optical detection device. It is.

In this liquid image forming apparatus, the light emitting portion of the optical detecting device as the layer thickness detecting means is provided by:
Light is emitted toward at least a part of the region of the developer support that supports the thinned liquid developer. Then, the light receiving unit of the optical detection device receives the light reflected on the part and performs optical detection. The color of the surface of the developer support is different from that of the liquid developer, and the optical detection device is sensitive only to the color of the liquid developer. The intensity of the reflected light received by the light receiving unit increases or decreases as the color becomes darker. Conversely, as the liquid developer layer is thinner and the color of the developer is lighter, the intensity of the reflected light received by the light receiving section is smaller or larger, and particularly, in a portion where the liquid developer layer is not formed, The reflected light intensity becomes minimum or maximum. Utilizing such a relationship between the reflected light intensity and the layer thickness,
The layer thickness can be detected indirectly. Then, based on the result of the detection of the reflected light intensity, the layer thickness uniformity determining means determines whether or not the thin layer thickness of the liquid developer on the developer support surface is uniform in the direction of movement of the developer support surface. Is determined. For example, if the width of change in reflected light intensity received by the light receiving unit is smaller than a predetermined width, the layer thickness is determined to be uniform, and if the width of change in reflected light intensity is larger than a predetermined width, the layer is determined to be uniform. It is determined that the thickness is non-uniform.

According to a third aspect of the present invention, in the liquid image forming apparatus of the first aspect, the color of the surface of the developer support is different from the color of the liquid developer, and The developer support has a light-emitting unit that emits light toward at least a part of a region that supports the thinned liquid developer, and a light-receiving unit that receives reflected light reflected on the part, An optical detection device having sensitivity only to the color of the surface of the developer support itself is used, and based on the detection result by the optical detection device, the layer thickness of the liquid developer on the surface of the developer support is reduced by the developer. A layer thickness uniformity judging means for judging whether or not the thickness is uniform in the direction of movement of the surface of the support is provided.

In this liquid image forming apparatus, the light emitting portion of the optical detecting device as the layer thickness detecting means includes:
Light is emitted toward at least a part of the region of the developer support that supports the thinned liquid developer. Then, the light receiving unit of the optical detection device receives the light reflected on the part and performs optical detection. The color of the developer support surface is different from that of the liquid developer, and the optical detection device is sensitive only to the color of the surface of the developer support itself. The liquid developer supported by the developer support has a function of blocking the color of the surface of the developer support itself. Thus, the thinner the layer thickness of the liquid developer, the deeper the color of the surface of the developer support itself,
The intensity of the reflected light received by the light receiving unit increases or decreases. In particular, the reflected light intensity becomes maximum or minimum in a portion where the liquid developer layer is not formed. Conversely, as the layer thickness of the liquid developer increases, the color of the surface of the developer support itself decreases, and the intensity of the reflected light received by the light receiving unit decreases or increases. By utilizing such a relationship between the intensity of reflected light and the layer thickness, the layer thickness can be indirectly detected. Then, based on the result of the detection of the reflected light intensity, the layer thickness uniformity determining means determines whether or not the thin layer thickness of the liquid developer on the developer support surface is uniform in the direction of movement of the developer support surface. Is determined. For example, if the width of change in reflected light intensity received by the light receiving unit is smaller than a predetermined width, the layer thickness is determined to be uniform, and if the width of change in reflected light intensity is larger than a predetermined width, the layer is determined to be uniform. It is determined that the thickness is non-uniform.

According to a fourth aspect of the present invention, in the liquid image forming apparatus of the second or third aspect, the color of the surface of the developer support itself is a complementary color of the color of the liquid developer. It is.

In this liquid image forming apparatus, since the color of the surface of the developer support itself is a complementary color of the color of the liquid developer, for example, light having an emission wavelength that is completely reflected by the liquid developer is used. When the detection is performed by using the light, the detection is performed by using the light having the emission wavelength such that the light is not reflected on the surface of the developer support, but is reflected on the surface of the developer support. When it is performed, the light is not reflected by the liquid developer. As described above, by making the color of the surface of the developer support itself a complementary color of the color of the liquid developer, the influence of the thickness of the liquid developer layer on the reflected light intensity appears more remarkably.

According to a fifth aspect of the present invention, in the liquid image forming apparatus of the first aspect, at least a part of the developer support is formed of a transparent material, and a part of the thin film detecting means is used as the layer thickness detecting means. Using an optical detection device having a light-emitting portion that emits light toward a portion supporting the layered liquid developer and a light-receiving portion that receives transmitted light transmitted through the portion, a detection result obtained by the optical detection device A layer thickness uniformity determining means for determining whether or not the layer thickness of the liquid developer on the surface of the developer support is uniform in the direction of movement of the surface of the developer support based on .

In this liquid image forming apparatus, at least a part of the developer support is formed of a transparent material, and a part of the developer support is emitted from a light emitting portion of the optical detecting device as the layer thickness detecting means. The light is emitted toward a portion that supports the thinned liquid developer. Then, the transmitted light transmitted through the portion is received by the light receiving section, and optical detection is performed. Here, of the developer support portion through which the light is transmitted and the liquid developer layer supported by the portion, the developer support portion is transparent, so that the thicker the layer thickness of the liquid developer is, the more the transmitted light becomes. Strength is reduced. Conversely, the thinner the layer thickness of the liquid developer,
The intensity of the transmitted light increases. In particular, the transmitted light intensity becomes maximum in a portion where the liquid developer layer is not formed. By utilizing such a relationship between the transmitted light intensity and the layer thickness, the layer thickness can be indirectly detected. Then, based on the result of detecting the transmitted light intensity, the layer thickness uniformity determination means determines whether or not the thin layer thickness of the liquid developer on the developer support surface is uniform in the direction of movement of the developer support surface. Is determined. For example, if the width of change in transmitted light intensity received by the light receiving unit is smaller than a predetermined width, the layer thickness is determined to be uniform, and if the change width of the transmitted light intensity is larger than a predetermined width, the layer is determined to be uniform. It is determined that the thickness is non-uniform.

According to a sixth aspect of the present invention, in the liquid image forming apparatus of the second, third, fourth, or fifth aspect, a plurality of the optical detection devices are provided in a width direction of the developer support. The layer thickness uniformity determination means is configured to determine whether or not the layer thickness of the liquid developer on the surface of the developer support is uniform in the width direction of the developer support based on a detection result by the optical detection device. It is characterized by having done.

In the liquid image forming apparatus, the layer thickness uniformity judging means detects the surface of the developer support on the basis of detection results obtained by a plurality of optical detectors provided in the width direction of the developer support. It is determined whether the thin layer thickness of the liquid developer is uniform in the width direction of the developer support.

According to a seventh aspect of the present invention, there is provided the second aspect of the present invention.
In the liquid image forming apparatus of (5) or (6), a notifying means for performing a predetermined notification when the layer thickness of the liquid developer is determined to be non-uniform by the layer thickness uniformity determining means is provided. It is characterized by the following.

In the liquid image forming apparatus, when the layer thickness uniformity determining means determines that the thin layer thickness of the liquid developer is non-uniform, a predetermined notification is performed by the notification means.

The invention according to claim 8 is the invention according to claims 2, 3, 4,
In the liquid image forming apparatus according to 5, 6, or 7, when the thickness uniformity determination unit determines that the layer thickness of the liquid developer is non-uniform, the stop control unit stops the image forming operation. Is provided.

In this liquid image forming apparatus, when the film thickness uniformity determining means determines that the thin layer thickness of the liquid developer is not uniform, the stop control means stops the image forming operation. . Thereby, it is possible to prevent image formation in a state where the thin layer thickness of the liquid developer is not uniform.

According to a ninth aspect of the present invention, as the liquid developing device, there is provided a liquid developer container for storing a liquid developer, and the liquid developer is supplied to the surface of the developer support to perform the developing operation. 4. The method according to claim 2, wherein a liquid developing device is used.
In the liquid image forming apparatus of 6, 7, or 8, when the layer thickness of the liquid developer is determined to be non-uniform by the layer thickness uniformity determining means, the liquid developer is stored in the liquid developer container. And a developer replenishing device for replenishing the developer.

In this liquid image forming apparatus, when it is determined that the thin layer thickness of the liquid developer is non-uniform,
The developer supply device supplies the liquid developer container with the liquid developer.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter, referred to as a copying machine) which is a liquid image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of an image forming unit of the copying machine. First, the configuration operation of the entire copying machine will be described with reference to FIG. The photoconductor drum 1 as a latent image carrier is driven to rotate at a constant speed in the direction of the arrow at the time of copying by a driving means such as a motor (not shown).
After being charged in the dark by the charging charger 2, an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 1 by the light 3 radiated by an exposure device (not shown). Thereafter, the electrostatic latent image is developed while passing through the portion of the liquid developing device 4. The toner image developed into the electrostatic latent image is transferred to a recording paper (not shown) that has passed through a transport path (not shown). After the recording paper is separated from the photosensitive drum 1, residual toner is removed by the cleaning blade 5.
The direction in which the cleaning blade 5 is provided may be the trailing direction or the counter direction. Thereafter, the residual potential of the surface of the photosensitive drum 1 is removed by the quenching lamp 6 to prepare for the next copy. The recording paper onto which the toner image has been transferred passes through a fixing device (not shown) and is discharged outside the apparatus.

FIG. 2 shows a schematic configuration of the liquid developing device 4. The liquid developing device 4 is provided with a liquid developer container 41 filled with a high-concentration, high-viscosity liquid developer 40, and partially submerged in the liquid developer 40 in the liquid developer container 41. The photosensitive drum 1
The developing roller 42 includes a developing roller 42 that supplies the liquid developer 40 on the surface of the developing roller 42 and a layer thickness regulating roller 43 as a thinning unit that thins the liquid developer 40 on the surface of the developing roller 42. Further, as the thinning means, for example, a blade or the like may be used. (Hereinafter, margin)

A developing bias voltage is applied to the developing roller 42 from a power source (not shown) to prevent the image on the photosensitive drum 1 from becoming dirty. The developing roller 42 is rotationally driven by a drive motor (not shown) in a direction indicated by an arrow, which is a reverse rotation direction to the photosensitive drum 1. This developing roller 42
On the right side in the figure, the layer thickness regulating roller 43 is disposed so as to be close to and opposed to. The layer thickness regulating roller 43 is rotationally driven by a drive motor (not shown) in the direction of the arrow, which is the same rotational direction as the developing roller 42.

The rotation of the developing roller 42 in the direction of the arrow causes the liquid developer 40 in the liquid developer container to adhere to the surface of the developing roller 42 and to be pumped up. It is uniform. Then, at an opposing portion between the developing roller 42 and the layer thickness regulating roller 43,
The layer thickness regulating roller 43 whose surface moves in the opposite direction to the surface of the developing roller 42 at the facing portion causes the layer thickness of the liquid developer 40 adhered to the developing roller 42 and the layer thickness regulating roller 43 to be adjusted. The thickness is regulated to a layer thickness corresponding to the distance, and the thickness is reduced. As a result, the layer thickness of the liquid developer 40 on the surface of the developing roller is uniformly thinned, and the
When the layer comes into contact with the latent image on the surface of the photosensitive drum 1, the latent image is visualized.

FIG. 3 is a block diagram showing a schematic configuration of a control unit of the copying machine. The control unit controls an image forming operation in the copying machine, and includes a CPU (Central Processing Unit) 101 for executing arithmetic control processing, a basic program for the arithmetic control processing, and a basic program for these processing. A ROM 102 for storing basic data, a RAM 103 for temporarily storing and saving various data,
An output port 104 from which an ON / OFF signal is output from the PU 101 to various driving units in the apparatus, an input port 105 from which an ON / OFF signal is input from various sensors in the apparatus to the CPU 101, and various sensors in the apparatus. CPU10
1 has an analog input port 106 to which analog data is input.

When the liquid developer 40 on the surface of the developing roller comes into contact with the latent image on the surface of the photosensitive drum 1, the layer thickness of the liquid developer 40 is uniform as described above. However, as described above, a shortage of the liquid developer supplied to the surface of the developer support occurs, or the inclination of the surface of the layer thickness regulating roller 43 for regulating the layer thickness on the developer support and the developer. A deviation from the inclination of the surface of the support or a deterioration of the layer thickness regulating roller 43 causes a variation in the layer thickness of the liquid developer 40 or the liquid developer layer is not formed. Parts may occur. In this state, if the latent image on the surface of the photosensitive drum 1 comes into contact with the latent image, the amount of toner adhered to the latent image becomes uneven. When the toner image having the unevenness is transferred to the recording paper in the transfer section, it is expected that the density of the image will be adversely affected.

Therefore, in the present embodiment, a configuration is adopted in which the uniformity of the layer thickness of the liquid developer 40 on the surface of the developing roller 42 can be determined. Hereinafter, this configuration and operation will be described. FIG. 4 shows the developing roller 42.
FIG. 4 is an enlarged view of the vicinity of an opposing portion between a roller and a layer thickness regulating roller 43.
In the present embodiment, at least the surface of the developing roller 42 as the developer support is configured to be different from the color of the liquid developer supported by the developing roller 42. Then, a portion of the developing roller 42 where the liquid developer 40 thinned by the layer thickness regulating roller 43 is supported, specifically, a portion facing the layer thickness regulating roller 43 in the rotation direction of the developing roller 42. A light emitting element 401 serving as a light emitting unit that emits light toward a predetermined detection point in a region downstream of the unit and opposed to the photosensitive drum 1, that is, in a region upstream of the development region, and on the detection position An optical detecting device having a light receiving element 402 as a light receiving unit for receiving the reflected light is provided as a layer thickness detecting means for detecting the layer thickness of the liquid developer having been reduced in thickness. With such an arrangement of the optical detecting device, the layer thickness is regulated by the layer thickness regulating roller 43 to a constant layer thickness, and the layer thickness of the liquid developer before development can be detected. Further, as an arrangement for emitting light from the light emitting element toward a detection point of the developing roller and receiving the reflected light reflected on the detection point by a light receiving element, the light emitting element in FIG. The arrangement is such that the element 401 and the light receiving element 402 are opposed to the detection location of the developing roller 42. The optical detection device is configured to have sensitivity only to the color of the liquid developer. Specifically, an example in which the color of the liquid developer is cyan will be described. For example, the light-emitting element 401 may be set to an emission wavelength close to the wavelength of cyan, and the light-receiving element 402 may be one that can detect natural light. . When the light emitting element 401 having a wavelength close to the color of the liquid developer is used as described above, basically, all the light emitted from the light emitting element 401 is reflected on the surface of the liquid developer 40 layer. Then, when the reflected light is detected by the light receiving element 402, as a result, the reflected light intensity of the cyan wavelength is measured. When detection is performed by the optical detection device having the light emitting element 401 and the light receiving element 402, the liquid developer layer is not uniform, and the color of the surface of the developing roller 42 itself is mixed with the liquid developer layer. In this case, cyan light is absorbed by the color of the surface of the developing roller 42 itself, so that the reflected light intensity decreases. In particular, in a portion where the liquid developer layer is not formed, the reflected light intensity has a minimum value. That is, when the liquid developer layer is thin, the reflected light intensity of cyan light is small, and when the liquid developer layer is thick, the reflected light intensity is large. In the copying machine of the present embodiment, the layer thickness is detected by utilizing the relationship between the liquid developer layer thickness and the reflected light intensity. As a result, the thickness of the liquid developer does not vary, or
It is possible to determine whether there is a portion where the liquid developer layer is not formed. Further, in the copying machine of the present embodiment, the thin layer thickness of the liquid developer 40 on the surface of the developing roller 42 is determined based on the detection result of the intensity of the reflected light.
It is determined whether it is uniform in the circumferential direction. In the copying machine of the illustrated example, the analog input port 10 of the control unit shown in FIG.
The detection signal from the light receiving element 402 is input to 6 and the CPU 101 as the layer thickness uniformity determining means determines whether or not the layer thickness of the liquid developer 40 is uniform. For example, if the width of the change in the intensity of the reflected light received by the light receiving element 402 is smaller than a predetermined width, the layer thickness is determined to be uniform, and if the width of the change in the intensity of the reflected light is larger than the predetermined width, It is determined that the layer thickness is not uniform. By determining the uniformity of the layer thickness in this way, it is possible to detect the occurrence of the layer thickness variation of the liquid developer and to detect the possibility of occurrence of an image defect due to the variation of the layer thickness. .

It is desirable that the surface of the developing roller 42 itself be configured to have a complementary color to the liquid developer 40 supported by the developing roller 42. For example, the light emitting element 4
When the light emitted from the light emitting element 40 is set to a wavelength such that all the light emitted from the developing roller 42 is reflected by the color of the liquid developer, the surface of the developing roller 42 itself, which is a complementary color of the color of the liquid developer, is formed.
No light from 1 is reflected. More specifically, when the color of the liquid developer is cyan, the complementary color red is used as the color of the surface of the developing roller 42 itself. When cyan light is used as the light from the light emitting element 401, the liquid developer 40 reflects all the light as described above, but does not reflect the light at all on the surface of the developing belt 42 itself. For this reason, when the color of the surface of the developing roller 42 itself appears as the color of the surface of the developing roller 42 that supports the liquid developer thinned by the change in the liquid developer layer thickness, the reflected light intensity becomes remarkable. As a result, the intensity of the reflected light becomes zero particularly in a portion where the liquid developer layer is not formed. On the other hand, when a color other than red, which is the complementary color, is used as the surface color of the developing roller 42, cyan light is reflected to some extent. For this reason, the amount of change in the reflected light intensity when the color of the surface of the developing roller 42 itself appears as the color of the surface of the developing roller 42 supporting the liquid developer thinned by the change in the liquid developer layer thickness Is smaller than when the complementary color is used. In particular, since white reflects all colors, it is not suitable as the color of the surface of the developing roller 42 itself in the present embodiment. From the above, the developing roller 42
If the color of the surface of the liquid developer is a complementary color of the color of the liquid developer, the influence of the liquid developer layer thickness on the reflected light intensity will appear more remarkably, so that the variation in the layer thickness can be detected more accurately. It is possible to do. Therefore, it is possible to more accurately detect the possibility of occurrence of an image defect due to the variation in the layer thickness.

In order to configure the optical detection device to have sensitivity only to the color of the liquid developer, a device that emits natural light is used as a light emitting element, and the liquid developer is selectively used as a light receiving element. A device that detects only light of the wavelength of the color may be used.

Further, if a plurality of the optical detecting devices are provided in the axial direction of the developing roller 42, it is possible to detect the variation in the liquid developer layer thickness in the axial direction. FIG. 5 is a perspective view of the developing roller 42 when three optical detecting devices are installed in the axial direction of the developing roller 42. Although the photosensitive drum 1 and the layer thickness regulating roller 43 are not shown, they have the same positional relationship as shown in FIG.
The light emitting element 401 and the light receiving element 402 are
It is installed in the rotation direction on the downstream side of the part facing the layer thickness regulating roller 43 and on the part facing the photoreceptor drum 1, that is, on the upstream side of the developing area. in this way,
By installing a plurality of the optical detecting devices in the axial direction of the developing roller 42, for example, when the layer thickness in the axial direction becomes non-uniform due to the inclined mounting of the developing roller 42 and the layer thickness regulating roller 43. Can be easily detected. Therefore, it is possible to more accurately detect the variation in the layer thickness of the liquid developer and more accurately detect the possibility of occurrence of an image defect. As the number of optical detection devices provided in the axial direction increases, the number of samples at the layer thickness measurement point increases, and the layer thickness in the axial direction can be accurately detected.

In this copying machine, the CPU 101
If the layer thickness is determined to be non-uniform, a display signal is output to a display panel serving as a notification unit via the output port 104, and a display of a development defect is displayed on the display panel, and copying is performed. The image forming operation of the machine is stopped. As described above, by notifying the user of the development failure, the user can quickly perform the subsequent processing, and the operability is improved. Further, at this time, by stopping the image forming operation of the copying machine, it is possible to prevent a defective image from being formed by the image forming operation. Therefore, waste of recording paper due to misprinting can be eliminated.

In the case where the CPU 101 determines that the layer thickness is not uniform, the CPU 101 may, for example, be configured to display only a development defect without stopping the operation of the entire apparatus. Good. In this case, the user can stop the apparatus after viewing the output image on the recording paper, so that the usability is improved when the image formation needs to be performed quickly even if the image quality is somewhat poor.

The lack of the liquid developer in the liquid developer container 41 may cause the layer thickness to be non-uniform. Therefore, the control unit may be configured such that when the CPU 101 determines that the layer thickness is non-uniform, the liquid developer container 41 is newly supplied with liquid developer by a supply unit (not shown). Thus, it is possible to prevent the layer thickness from being varied due to the lack of the liquid developer.

In general, when an optical detection device for detecting reflected light from a detection target is used, it is better to detect light having a dominant wavelength in the reflected light. This makes it easier to detect the fluctuation of the light as compared with the case of performing the above. Therefore, in the above-mentioned copying machine, the color of the surface of the developing roller 42 itself as the color of the surface of the developing roller 42 supporting the thinned liquid developer depends on the properties of the liquid developer and the thickness of the liquid developer layer. If it is dominant, it is preferable to use an optical detection device having sensitivity only to the color of the surface of the developing roller 42 itself. In this case, the light emitting element 401
The light reflected from the developing roller 42 is not the color of the liquid developer but the color of the surface of the developing roller 42 itself. The liquid developer supported by the developing roller 42 has a function of blocking light reflected from the surface of the developing roller 42 itself. Therefore, as the layer thickness of the liquid developer 40 becomes smaller, the developing roller 42 becomes thinner.
The color of the surface itself becomes darker, and the intensity of the reflected light received by the light receiving unit increases. In particular, the reflected light intensity becomes maximum in a portion where the liquid developer layer is not formed. Conversely, as the layer thickness of the liquid developer 40 increases, the color of the surface of the developing roller 42 decreases, and the intensity of the reflected light received by the light receiving unit decreases. By utilizing such a relationship between the intensity of reflected light and the layer thickness, the layer thickness can be indirectly detected.
Then, based on the detection result of the reflected light intensity, it is determined whether the thin layer thickness of the liquid developer 40 on the surface of the developing roller 42 is uniform in the moving direction of the surface of the developing roller 42, that is, in the circumferential direction of the developing roller 42. be able to. For example, similarly to the case where the optical detection device is configured to have sensitivity only to the color of the liquid developer, a detection signal from the light receiving element 402 is input to the analog input port 106 of the control unit illustrated in FIG. The CPU 101 as the layer thickness uniformity determining means may determine whether the layer thickness of the liquid developer 40 is uniform. If the width of the change in the intensity of the reflected light received by the light receiving element 402 is smaller than a predetermined width, it is determined that the layer thickness is uniform. If the width of the change in the intensity of the reflected light is larger than the predetermined width, It is determined that the layer thickness is not uniform. Thus, it is possible to detect the occurrence of the variation in the layer thickness of the liquid developer and to detect the possibility of the occurrence of an image defect due to the variation in the layer thickness. Then, when the CPU 101 determines that the layer thickness is not uniform, the above-described corresponding operation is performed.

The optical detecting device is connected to the developing roller 42.
Even when the developing roller 42 is configured to have sensitivity only to the color of its own surface, it is preferable that the surface of the developing roller 42 is configured to be a complementary color of the liquid developer 40 supported by the developing roller 42. As a result, the influence of the liquid developer layer thickness on the reflected light intensity appears more remarkably, and it becomes possible to detect variations in the layer thickness more accurately. Therefore, it is possible to more accurately detect the possibility of occurrence of an image defect due to the variation in the layer thickness.

As described above, in this embodiment, only the liquid image forming apparatus having the liquid developing device using the developing roller 42 as the developer support has been described. The present invention may be applied to a liquid image forming apparatus having a developing device.

[Second Embodiment] Next, a copying machine according to another embodiment will be described. The basic configuration operation of the entire copying machine according to the present embodiment is the same as that of the apparatus shown in FIG. FIG. 6 shows a schematic configuration of an example of the liquid developing device of the copying machine. The example of FIG. 6 is an example of a liquid developing device using a developing belt 45 as a developer support.
The configuration of the control unit of the copying machine is the same as that of the control unit shown in FIG. First, the basic configuration and operation of the liquid developing device of FIG. 6 will be described. The liquid developing device includes a liquid developer container 41 filled with a high-concentration and high-viscosity liquid developer 40, three support rollers 44a,
A developing belt 45 stretched between 44b and 44c and having an appropriate tension, and a layer thickness of the liquid developer 40 on the surface of the developing belt 45 is regulated to make the liquid developer 40 thinner as shown in FIG. And a layer thickness regulating roller 43 similar to the above. Of the three support rollers, the support roller 44a is provided so as to be partially submerged in the liquid developer 40 in the liquid developer container 41, and rotates in the direction of the arrow to partially support the surface of the support roller 44a. Developing belt 4 wrapped around
The structure is such that the liquid can be pumped to the five surfaces. The support rollers 44b and 44c are provided so as to be close to and along the photoconductor surface. The developing belt 45 is in contact with the surface of the photosensitive drum 1 in a developing area A between the support rollers 44b and 44c. Although a gap is provided between the developing belt 45 and the surface of the photosensitive drum 1 in the drawing, the surface of the developing belt 45 and the surface of the photosensitive drum 1 are actually in contact with each other. Thus, development with the liquid developer on the belt is possible. Further, as the thinning means, for example, a blade or the like may be used. The number of support rollers is 3
The number is not limited to a book, and any number of books may be used depending on the mechanical configuration as long as a developing area where the photosensitive drum 1 and the developing belt 45 come into contact can be secured.

A developing bias voltage is applied to the developing belt 45 from a power source (not shown) to prevent the image on the photosensitive drum 1 from becoming dirty. The developing belt 45 is driven to rotate in the direction indicated by the arrow, which is the direction opposite to the direction of rotation of the photosensitive drum 1, by driving the support roller 44a in the direction indicated by the arrow by a drive motor (not shown). The support roller 4
On the right side of FIG. 4a, the layer thickness regulating roller 43 is disposed so as to be close to and opposed to. The layer thickness regulating roller 43 is driven to rotate in a direction indicated by an arrow, which is the same rotation direction as the developing belt 45, by a drive motor (not shown). The support roller 44
The liquid developer 40 in the liquid developer container adheres to the surface of the developing belt 45 and is drawn up by the rotation of the arrow a in the direction of the arrow, but the layer thickness of the liquid developer 40 attached is not uniform. The developing belt 45 and the layer thickness regulating roller 4
3, a layer thickness regulating roller 43 whose surface moves in a direction opposite to the surface of the developing belt 45 at the facing portion.
Thereby, the layer thickness of the liquid developer 40 attached is regulated to a layer thickness corresponding to the distance between the developing belt 45 and the layer thickness regulating roller 43, and the layer is made thin. As a result, the layer thickness of the liquid developer 40 on the surface of the developing belt is made uniform and thin, and the uniformized liquid developer 40 layer contacts the latent image on the surface of the photosensitive drum 1 in the developing area. The latent image is visualized.

In a liquid developing device that performs development using such a developing belt 45, the liquid developer layer surface is in contact with the surface of the photosensitive drum 1 as compared with a liquid developing device that performs development using a developing roller. It is generally considered advantageous for development because of the long time.

In the liquid developing device of the copying machine according to the present embodiment, the developing belt 45 as a developer support on which the liquid developer 40 is thinned is formed of a transparent material. Then, the portion of the developing belt 45 where the liquid developer 40 thinned by the layer thickness regulating roller 43 is supported, specifically, the portion facing the layer thickness regulating roller 43 in the moving direction of the developing belt 45. A light emitting element 403 serving as a light emitting unit that emits light toward a predetermined detection point in a region downstream of the unit and opposite to the photosensitive drum 1, that is, in a region upstream of the development region, and An optical detecting device having a light receiving element 404 as a light receiving unit that receives transmitted light is provided as a layer thickness detecting unit that detects the layer thickness of the thinned liquid developer. FIG. 7 is an enlarged view around the optical detection device. The direction of the arrow in the drawing indicates the moving direction of the developing belt 45. The developing region is located on the downstream side in the moving direction, and the portion facing the layer thickness regulating roller 43 is located on the upstream side in the moving direction. In the arrangement shown in FIG. 7, the light-emitting element 403 and the light-receiving element 404 emit light from the light-emitting element toward the detection point, and receive transmitted light transmitted through the detection point by the light-receiving element. Thus, the developing belt 45 and the liquid developer layer on the developing belt are sandwiched. With such an arrangement of the optical detection device, the layer thickness can be reduced to a constant layer by the layer thickness regulating roller 43, and the layer thickness of the liquid developer before development can be detected. The optical detector detects light emitted from the light emitting element 403 and transmitted through the liquid developer 40 layer and the developing belt 45 by the light receiving element 404 as shown in FIG. As described above, when the transmitted light is detected by the optical detection device, the liquid developer layer is non-uniform, and if there is a portion where the liquid developer layer is thick, light is difficult to transmit, so that the transmitted light intensity decreases. . Conversely, if there is a portion where the liquid developer layer is thin, light is easily transmitted, so that the transmitted light intensity increases. In particular, the transmitted light intensity becomes maximum in a portion where the liquid developer layer is not formed. In the copying machine of the present embodiment, the layer thickness is indirectly detected using the relationship between the liquid developer layer thickness and the transmitted light intensity.
Then, based on the detection result of the transmitted light intensity, it is determined whether or not the thin layer thickness of the liquid developer 40 on the surface of the developing belt 45 is uniform in the surface moving direction of the developing belt 45, that is, in the circumferential direction of the developing belt 45. In the copying machine of the illustrated example, a detection signal from the light receiving element 404 is input to the analog input port 106 of the control unit shown in FIG. 3, and the layer of the liquid developer 40 is controlled by the CPU 101 as a layer thickness uniformity determining unit. It is determined whether the thickness is uniform. For example, the light receiving element 4
If the width of the change in transmitted light intensity received in step 04 is smaller than a predetermined width, it is determined that the layer thickness is uniform. If the width of the change in transmitted light intensity is larger than the predetermined width, the layer thickness is not uniform. Is determined. By determining the uniformity of the layer thickness in this way, it is possible to detect the occurrence of the layer thickness variation of the liquid developer and to detect the possibility of occurrence of an image defect due to the variation of the layer thickness. . (Hereinafter, margin)

In the copying machine of this embodiment, if a plurality of the optical detecting devices are provided in the width direction of the developing belt 45, it is possible to detect the variation in the thickness of the liquid developer layer in the width direction. Therefore, it is possible to more accurately detect the variation in the layer thickness of the liquid developer. Therefore, it is possible to more accurately detect the possibility of occurrence of an image defect.

When the CPU 101 determines that the layer thickness is non-uniform, the same effect can be obtained by performing the corresponding operation as described in the first embodiment.

Further, in the optical detecting device of the first embodiment, the light reflected by the color of the liquid developer is distinguished from the light reflected by the color of the surface of the developing roller 42 itself carrying the liquid developer. Then, the emission wavelength of the light emitting element of the light detecting device and the sensitivity wavelength of the light receiving element are set according to the color of the liquid developer or the color of the surface of the developing roller 42 itself. However, in the present embodiment, unlike the case of the first embodiment, the developing belt 4
Since 5 is made of a transparent material, only the thickness of the liquid developer layer contributes to the transmittance of the light transmitting portion.
Therefore, it is not necessary to select the emission wavelength or the reception wavelength, and natural light may be used, for example.

In the second embodiment, the developing belt 45 is made of a transparent material, and the layer thickness of the liquid developer on the surface of the developing belt is detected by detecting the light transmitted through the developing belt 45. Although only an example of determining whether or not uniformity is determined in the surface movement direction has been described, the developing belt 45 is made of a transparent material, and a thin liquid developer is used as the layer thickness detecting means. An optical detection device having a light-emitting portion that emits light toward the portion to be supported and a light-receiving portion that receives light reflected on the portion is used. Based on the detection result by the optical detection device, the surface of the developing belt is The layer thickness of the liquid developer may be determined to be uniform in the direction of movement of the developer support surface. And even in the case of such a configuration, since only the liquid developer layer thickness contributes to the reflected light intensity of the reflected light, it is not necessary to particularly select an emission wavelength or a reception wavelength, and for example, natural light is used. It is also possible.

In the first and second embodiments, the example in which the CPU 101 in the copying machine has a function as a layer thickness uniformity judging means has been described. However, the layer thickness uniformity judging means is not provided in the copying machine. Alternatively, a configuration in which only the layer thickness detecting means such as the optical detecting means is provided may be adopted. In this case, the detection signal from the layer thickness detecting means is outputted to a device other than the copying machine connected to the copying machine, for example, a host computer. Then, the host computer may perform a predetermined operation based on the detection signal, for example, stop the copier main unit, or perform a display on a display unit as a notification unit of the copier main unit.

[0048]

According to the first to ninth aspects of the present invention, the thickness of the liquid developer thinned by the thinning means is detected, and the detection result is used to detect the thickness of the liquid developer. It is possible to determine whether there is a variation in the layer thickness or whether there is a portion where the liquid developer layer is not formed. Therefore, there is an excellent effect that it is possible to detect such a possibility that an image defect may occur due to the variation in the thickness of the liquid developer layer by making such a determination.

According to the second to ninth aspects of the present invention, it is determined whether or not the layer thickness of the thinned liquid developer on the surface of the developer support is uniform in the direction of movement of the surface of the developer support. Since the determination can be made, there is an excellent effect that it is possible to detect the occurrence of the variation in the layer thickness and to detect the possibility of occurrence of an image defect due to the variation in the layer thickness.

In particular, according to the invention of claim 4, the color of the surface of the developer support itself is made complementary to the color of the liquid developer, so that the reflected light intensity due to the liquid developer layer thickness is reduced. Since the influence appears more remarkably, there is an excellent effect that the variation in the layer thickness can be detected more accurately, and the possibility of occurrence of an image defect can be detected more accurately.

According to the sixth aspect of the present invention, the layer thickness uniformity determining means determines whether or not the thin layer thickness of the liquid developer on the surface of the developer support is uniform in the width direction of the developer support. Therefore, there is an excellent effect that the variation in the layer thickness of the liquid developer can be detected more accurately, and the possibility of occurrence of an image defect can be detected more accurately.

According to the invention of claim 7, when the thin layer thickness of the liquid developer is determined to be non-uniform, a predetermined notification is performed by the notification means, so that the user can perform the subsequent processing. Has an excellent effect that the operability can be increased quickly.

According to the eighth aspect of the present invention, it is possible to prevent a defective image from being formed by performing an image forming operation in a state where the thin layer thickness of the liquid developer is not uniform. Therefore, waste of recording paper due to misprinting can be eliminated.

According to the ninth aspect of the present invention, when it is determined that the thin layer thickness of the liquid developer is not uniform, the liquid developer container is supplied with the liquid developer by the developer supply device. Therefore, there is an excellent effect that it is possible to prevent variations in the layer thickness caused by the lack of the liquid developer.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming unit of a copying machine according to an embodiment.

FIG. 2 is a front view showing a schematic configuration of a liquid developing device of the copying machine.

FIG. 3 is a block diagram showing a schematic configuration of a control unit of the copying machine.

FIG. 4 is an enlarged view of the vicinity of an opposing portion between a developing roller 42 and a layer thickness regulating roller 43 of the liquid developing device.

FIG. 5 is a perspective view of the developing roller in a case where three optical detecting devices are installed in the axial direction of the developing roller of the liquid developing device.

FIG. 6 is a schematic configuration diagram of an example of a liquid developing device of a copying machine according to another embodiment.

FIG. 7 is an enlarged view around the optical detection device of the liquid developing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charging charger 3 light 4 liquid developing device 40 liquid developer 41 liquid developer container 42 developing roller 43 layer thickness regulating rollers 44a, 44b, 44c supporting roller 45 developing belt 401, 403 light emitting element 402, 404 light receiving element 5 Cleaning blade 6 Quenching lamp

Claims (9)

[Claims] A liquid developer having a high concentration and a high viscosity on a surface thereof; and a thinning means for thinning the liquid developer on the developer support. The developing operation of bringing the thinned liquid developer into contact with the surface of the latent image carrier by moving the surface of the developer support and visualizing the electrostatic latent image formed on the surface of the latent image carrier is performed. A liquid image forming apparatus provided with a liquid developing device, wherein a layer thickness detecting means for detecting a layer thickness of the thinned liquid developer is provided. 2. The liquid image forming apparatus according to claim 1, wherein the color of the surface of the developer support is different from the color of the liquid developer, and the layer thickness detecting means is provided on the surface of the developer support. A light-emitting unit that emits light toward at least a part of a region that supports the thinned liquid developer, and a light-receiving unit that receives reflected light reflected on the part, and Using an optical detection device having sensitivity only to color, based on the detection result by the optical detection device, whether the layer thickness of the liquid developer on the surface of the developer support is uniform in the direction of movement of the surface of the developer support. A liquid image forming apparatus comprising a layer thickness uniformity judging means for judging whether or not the liquid image is formed. 3. The liquid image forming apparatus according to claim 1, wherein the color of the surface of the developer support is different from the color of the liquid developer, and the layer thickness detecting means is provided on the surface of the developer support. A light-emitting unit that emits light toward at least a part of a region that supports the thinned liquid developer, and a light-receiving unit that receives light reflected on the part, and the developer support Using an optical detection device having sensitivity only to the color of the surface of the developer itself, the layer thickness of the liquid developer on the surface of the developer support is adjusted based on the detection result by the optical detection device in the direction of movement of the surface of the developer support. A liquid image forming apparatus provided with a layer thickness uniformity judging means for judging whether or not the liquid is uniform. 4. The liquid image forming apparatus according to claim 2, wherein the color of the surface of the developer support itself is a complementary color of the color of the liquid developer. 5. A liquid image forming apparatus according to claim 1, wherein at least a part of said developer support is formed of a transparent material, and said part of said liquid thinned is used as said layer thickness detecting means. Using an optical detection device having a light-emitting portion that emits light toward a portion supporting the developer and a light-receiving portion that receives transmitted light transmitted through the portion, the developing is performed based on a detection result by the optical detection device. 1. A liquid image forming apparatus, comprising: a layer thickness uniformity determining means for determining whether or not a layer thickness of a liquid developer on a surface of a developer support is uniform in a moving direction of the surface of the developer support. 6. The liquid image forming apparatus according to claim 2, wherein a plurality of said optical detecting devices are provided in a width direction of said developer support, and said plurality of optical detecting devices are provided. The layer thickness uniformity determination means is configured to determine whether or not the layer thickness of the liquid developer on the developer support surface is uniform in the width direction of the developer support based on the detection result. Liquid image forming apparatus. 7. A liquid image forming apparatus according to claim 2, wherein said layer thickness uniformity determining means determines that said layer thickness of said liquid developer is non-uniform. And a notifying means for performing a predetermined notifying operation. 8. A liquid image forming apparatus according to claim 2, wherein said film thickness uniformity determining means determines that the layer thickness of said liquid developer is non-uniform. A liquid image forming apparatus provided with stop control means for stopping an image forming operation when the liquid image forming operation is performed. 9. A liquid developing device having a liquid developer container containing a liquid developer and supplying the liquid developer to the surface of the developer support to perform the developing operation as the liquid developing device. The liquid image forming apparatus according to any one of claims 2, 3, 4, 5, 6, 7, and 8, wherein the layer thickness uniformity determining means determines that the layer thickness of the liquid developer is non-uniform. And a developer supply device for supplying a liquid developer to the liquid developer container.