JPH0690587B2 - Cleaning equipment for wet copiers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a so-called wet copying in which an electrostatic latent image formed on an image bearing member such as a photoconductor is developed by a liquid developer containing toner. Regarding the machine. In particular, it relates to a cleaning device for removing toner remaining in a specific device in a copying machine.

As the device in which the toner remains, it is conceivable that the photosensitive member after the transfer operation is completed, or the toner of different colors is replaced such as a developing device used in a wet color copying machine.

2. Description of the Related Art As a cleaning device used in the above wet copier, there is known a cleaning device that removes untransferred toner remaining on the photoconductor after the transfer is completed by connecting a roller moistened with a cleaning liquid to the photoconductor. Has been. In this case, the cleaning liquid that wets the roller is supplied from the cleaning liquid tank and then collected again in that tank.

The recovered cleaning liquid contains the toner removed from the photoconductor, and this toner is recovered from the cleaning liquid by a so-called electrodeposition method and stored in the recovery container.

Here, in the conventional toner collecting work, the electrodeposition work is started at the same time when the copying work is started. According to this, since the toner in the tank is always collected and the cleaning liquid is always kept clean, extremely good cleaning is performed. However, with this method, although it is essentially sufficient to collect only the concentrated toner, a large amount of cleaning liquid is scraped off during electrodeposition, and as a result, the collection container overflows immediately. There was a flaw. If this happens, the replacement cycle of the collection container becomes short.

In view of the above points, an object of the present invention is to provide a cleaning device capable of prolonging the replacement cycle of the toner recovery container while maintaining good cleaning property.

Structure The above-mentioned object is to dispose toner concentration detecting means in the cleaning liquid tank and collect toner when the toner concentration detecting means detects that the toner concentration in the tank exceeds a predetermined value. It is achieved by doing the work.

Hereinafter, the present invention will be described based on examples.

FIG. 1 shows an example of a wet copier. In the figure, an original document (not shown) is placed on the contact glass 1 with the image surface facing downward, and is pressed by the pressure plate 2.

An exposure optical system E is provided below the contact glass 1. This exposure optical system E includes a lamp 10 and mirrors 11, 12, 13, 1
5 and has a lens 14, and when the document is illuminated by the lamp 10, the reflected light is guided to the photoconductor 3 through the lens and the mirror.

The photoconductor 3 is formed in a drum shape and rotates clockwise in the drawing. Around the photoconductor 3, as viewed in the rotational direction of the photoconductor, a charging charger 4, a developing device 5, a transfer charger 7, a separating unit 8, and a cleaning device 9 are arranged in this order.
(In particular, the cleaning unit 9a) is provided.

The surface of the photoconductor 3 is uniformly charged by the charging charger 4 before being subjected to the exposure action of the exposure optical system E. Therefore, an electrostatic latent image corresponding to the original image is formed on the surface of the photoconductor by the above-mentioned exposure action.

The electrostatic latent image is then subjected to development work by the developing device 5 to be a visible image. As shown in FIG. 2, the developing device 5 is connected to a black developer tank 29b via a developer supply pipe 32b and a pump 31b. A liquid black developer 30b made by dispersing black toner in a mother liquor is stored in the tank 29b. The black developer 30b is supplied to the pump 31b and the supply pipe 32.
It is supplied to the developing device 5 by b, so that the electrostatic latent image on the photoconductor 3 becomes a black visible image.

The developer that has completed the developing operation is collected again in the developer tank 29b via the discharge pipe 36. Reference numeral 34b is a black toner bottle, and 35 is a mother liquor bolt.

While the above operations are being performed, the transfer paper in the paper feed cassette 16 in FIG.
8. It is fed to the registration roller 22 by the feed roller 20. This transfer paper is sent out from the registration roller 22 in time with the black visible image on the photoconductor 3 and is superimposed on the visible image.

Then, the black visible image is transferred onto the transfer paper by the transfer charger 7, and the transfer paper is separated from the photoconductor 3 by the separation unit 8. The separated transfer paper is a fixing device.
After having been subjected to the fixing work by 24, it is discharged to the tray 27 by the sending-out roller 26.

After the transfer operation by the transfer charger 7, the toner that has not contributed to the transfer, so-called untransferred toner, remains on the photoconductor 3. The untransferred toner moves upward as the photoconductor 3 rotates and is conveyed to the cleaning unit 9a of the cleaning device 9.

The cleaning device 9 removes the untransferred toner from the photoconductor 3 as the portion to be cleaned. The cleaning device 9 of the embodiment includes a cleaning liquid tank 100 containing a cleaning liquid 101, as shown in FIG.
It has a pump 102 for pumping the cleaning liquid 101, a supply pipe 43 for guiding the pumped cleaning liquid to the cleaning unit 9a, and a transfer pipe 44 for guiding the cleaning liquid in the cleaning unit 9a into the cleaning liquid tank 100. ing.

When the cleaning liquid sent to the cleaning unit 9a via the supply pipe 43 comes into contact with the untransferred toner on the photoconductor 3, the untransferred toner is redispersed in the cleaning liquid, and the untransferred toner is transferred from the photoconductor 3 to the cleaning liquid. To be removed. The cleaning liquid in which the untransferred toner is dispersed passes through the discharge pipe 44 and is returned to the tank 100 again.
Return to. In this way, the untransferred toner on the photoconductor 3 is cleaned while the cleaning liquid circulates.

When the cleaning operation is repeatedly performed, the toner concentration in the cleaning liquid 101 gradually increases. When the density exceeds the limit, the untransferred toner and re-dispersion in the cleaning unit 9a are reduced, and cleaning is insufficient.

The following measures are being taken to resolve this. As shown in FIG. 3, an electrode roller 105 is provided in the tank 100 so as to be immersed in the cleaning liquid, and a toner concentration detecting means 110 is further provided. The scraper plate 116 is in contact with the electrode roller 105, and the toner collecting container 107 is arranged below the blade 116.

The toner concentration detecting means 110 detects the toner concentration in the cleaning liquid 101. The structure is not particularly limited, but, for example, the structure shown in FIG. 4 can be considered. As shown in FIG.
And a lamp 111 which is a light emitting element and a photo sensor 112 which is a light receiving element. Both the lamp 111 and the photo sensor 112 are fixed to the housing 113. A cleaning liquid inlet 114 is provided at the top of the housing 113, and a cleaning liquid supply tube 115 is provided in this.
Are connected.

When detecting toner concentration, pump through the tube 115 1
The cleaning liquid is supplied into the housing 113 from 02 (FIG. 2). The cleaning liquid that has flowed into the housing 113 enters between the lamp 111 and the photo sensor 112 and
Changes the transmittance of light emitted from 111. This change in transmittance gives a change in current to the photosensor 112, which is converted into a voltage and further compared with the reference voltage value. This determines whether the toner concentration in the cleaning liquid is high or low.

When the density is higher than a predetermined value, a bias voltage (for example, about 800V) is applied to the electrode roller 105 in FIG.
Toner in the cleaning liquid is electrodeposited on the roller. The toner is scraped off by the blade 116 and discharged to the collection container 107.

As described above, since electrodeposition by the electrode roller 105 is performed only when the toner concentration of the cleaning liquid 101 becomes equal to or higher than a predetermined value, only the concentrated toner is efficiently collected in the collection container 107, and cleaning is performed. The inconvenience that a large amount of the liquid itself is recovered is eliminated. Therefore,
It takes a long time until one toner collection container 107 is full, and the toner collection container replacement cycle can be lengthened accordingly.

In addition, the reference value of the toner density that is the reference for starting the electrodeposition is
For example, it is set to a value corresponding to the toner density when the background image is smeared on the copied image.

Next, another embodiment will be described. In this embodiment, the cleaning device according to the present invention is applied to a wet monochromatic color copying machine.

Whenever it is a monochromatic color copier, its mechanical construction is very similar to the black copier described above with reference to FIG. The different points will be described below. The same members as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted. First, as shown in FIG.
One present agent supply pipe 52b, 52m, 52c, 52y and one cleaning liquid supply pipe 53 are provided. One developer supply pipe
It is the second that 52b is connected to the black developer tank 29b.
There is no difference from the illustrated embodiment. The other three supply pipes 52m, 52c,
52y is connected to a magenta developer tank, a cyan developer tank, and a yellow developer tank, respectively. For simplification, the drawing shows the state where the supply pipe 52m is connected to the magenta color developer tank 29m. Other supply pipe 5
The configuration is the same for 2c and 52y. The magenta color developer tank 29m or other tank is arranged at a proper position in the copying machine as shown in FIG.

In this monochromatic color copying machine, by selecting the developer to be supplied to the developing device 55, a copied image of a desired color other than black can be obtained. For example, when a magenta color copy image is desired, the magenta color developer 30m is supplied to the developing device 55 by the pump 31m.

It is assumed that another color, for example, black color is developed before the magenta color development. In this case, if the magenta color developer is supplied immediately after the completion of the black development work, the black toner remaining inside the developing device 55 mixes with the magenta color developer and a clear copy image cannot be obtained.

Therefore, a cleaning device 59 is provided to remove the toner remaining in the developing device 55 from the developing device. That is, in this embodiment, the developing device 55 is the portion to be cleaned by the cleaning device 59. The structure itself of the cleaning device 59 is almost the same as that of the embodiment of FIG.
The difference is that the supply pipe 53 and the discharge pipe 54 are connected not to the cleaning section 9a but to the developing device 55.

In this configuration, when the development work for each color is completed, the cleaning liquid 101 is poured into the developing device 55 via the supply pipe 53 before the development work for the next different color is performed. This cleaning liquid is collected in the tank 100 again through the discharge pipe 36 and the switching valve 37 together with the residual toner in the developing device 55. As a result, the developing device 55 is cleaned.

When the cleaning work is repeated, the toner concentration in the cleaning liquid 101 gradually increases. In this case, a collection container 107 (Fig. 3) using the electrode roller 105
The recovery of toner is similar to that in the embodiment of FIG. Also in this case, in order to prolong the replacement cycle of the collection container 107, the electrodeposition work is performed in a timely manner while detecting the toner concentration.

Also in the embodiment shown in FIG. 5, a cleaning device (hereinafter referred to as a photoconductor cleaning device) is required to remove the untransferred toner from the photoconductor 3. In FIG. 5, the photoconductor cleaning device is indicated by reference numeral 60.

This photoconductor cleaning device 60 includes a black developer tank 29.
The black developer 30b in b is sent to the cleaning unit 9a via the pump 62 and the supply pipe 62, and the black developer 30b is used to disperse and remove the untransferred toner on the photoconductor 3. The black developer that has completed the cleaning operation is collected again in the tank 29b by the discharge pipe 64. As the cleaning liquid thus recovered, the black image agent contains magenta and other color toners in addition to the black toner. However, as long as this black developer is returned to the black developer tank 29b, there is no concern about deterioration of image quality due to color mixing.

The photoconductor cleaning device 60 performs cleaning using the black developer 30b, and is not particularly an embodiment of the present invention. However, it goes without saying that the cleaning device according to the present invention as shown in FIG. 2 can be used as the photoconductor cleaning device in a monochromatic color copying machine.

When the toner collecting container 107 is filled with the collected toner, it is necessary to replace the container with a new container.
To do that, we first need to know that the container is full.

As a means to know that the container is full, the float is floated on the liquid in the container, and when this float rises to the limit height, the switch is operated by this float to display on the lamp etc. There is a switch system. However, in this embodiment, the collection container 107
Since the so-called sludge-like toner concentrated inside is collected, it is conceivable that the float switch system cannot accurately detect the toner.

Therefore, as shown in FIGS. 6 and 7, it is convenient to provide an optical level sensor 65 on the upper part of the container 107 to optically detect the liquid level. In this case, the optical path of the optical level sensor 65 is contaminated, the lower end of the toner recovery pipe 66 is bent outward so that the sensor does not malfunction due to it, and the recovered toner propagates along the wall surface of the recovery container 107. It is good to let it flow down.

When replacing the collection container 107, the optical level sensor 65 is left as it is and only the container is replaced with a new one.

Effect According to the present invention, while maintaining a good cleaning property,
The replacement cycle of the toner recovery container can be lengthened.

[Brief description of drawings]

FIG. 1 is a side sectional view of a wet copier using an embodiment of the present invention, FIG. 2 is a view around the photosensitive member of FIG. 1, and FIG. 3 is a view around the cleaning liquid tank of FIG. FIG. 4 is a cross-sectional view of an example of toner concentration detecting means, FIG. 5 is a side view of another embodiment, and FIGS. 6 and 7 are views showing a toner recovery container. 3 image carrier 30b, 30m liquid developer 100 cleaning liquid tank 101 cleaning liquid 102,43,44,53,54 cleaning liquid circulating means 110 toner concentration detection means 107 Collection container

Claims (1)

[Claims] 1. A cleaning liquid tank for containing a cleaning liquid in a cleaning device of a wet copying machine in which an electrostatic latent image formed on an image carrier is developed by a liquid developer containing toner. A cleaning liquid circulating unit that supplies the cleaning liquid in the cleaning liquid tank to the portion to be cleaned, removes the toner from the portion to be cleaned, and then collects the cleaning liquid in the cleaning liquid tank again; The toner concentration detecting means for detecting the concentration of the toner contained in the cleaning liquid and the toner collecting means for collecting the toner in the cleaning liquid by electrodeposition and discharging the toner in the collecting container. Toner collection work by the toner collection means is performed when the density detection value by the detection means exceeds a predetermined value. Cleaning device according to claim.