JP2000305366A - Wet image forming method and apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To adjust a component of a collected developer collected from a developer carrying member and to reuse the collected developer without installing a special detecting means or a measuring means. To provide a wet image forming method and apparatus which can be used. SOLUTION: Image data is read by a writing control board 104, and the area of an image area formed on a photoreceptor 1, the image density thereof, and the area of a non-image area are calculated from the image data. The area of the image part and the non-image part calculated by the writing control board 104 and the calculated value of the image density are
The amount is transmitted to the board 100, and the amount of developer particles and the amount of solvent estimated to be consumed by actual image formation are specified based on the calculated values. Developer particle replenishment control means 106 for controlling the replenishment amount of developer particles replenished into developer recovery tank 47 through developer particle replenishment pipe 61 based on the consumption amounts of the developer particles and the solvent; The solvent replenishment control means 107 for controlling the replenishment amount of the solvent replenished into the developer recovery tank 47 through the pipe 62 is controlled by the CPU board 100 to convert the components of the recovered developer to the same components as the components of the start agent. Readjust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a wet image, such as a copying machine, a facsimile, and a printer, which form an image using a liquid developer having a high density and a high viscosity by a wet electrophotographic technique. is there.

[0002]

2. Description of the Related Art In an electrophotographic system, for example, an electrostatic latent image is formed on a photosensitive member as a latent image carrier based on image data, and is carried on a developing roller or a developing belt as a developer carrier. After the electrostatic latent image is visualized by the developed developer, an image is formed by transferring the visualized toner image on the photoreceptor to a recording medium such as transfer paper.

Further, various image forming apparatuses have been proposed in which the developer collected from the photoreceptor is recycled and reused. For example, an "image forming apparatus" described in Japanese Patent Application Laid-Open No. 9-127841 is one of them, and this image forming apparatus includes a latent image forming means for forming a latent image on an image carrier, and a Developing means for supplying a developer to the formed latent image to develop the latent image; transfer means for transferring the developer supplied to the image carrier by the developing means to a material to be transferred; Developer collecting means for collecting, from the image carrier, untransferred developer remaining after the developer supplied to the latent image of the body is not transferred to the material to be transferred by the transfer means, and the developer collecting means And a recycling unit for returning the developer other than the developer collected from a position corresponding to a specific area of the image carrier among the developers collected by the method to the developing unit. This image forming apparatus basically relates to dry electrophotography. Besides this,
Although many proposals have been made regarding the reuse of the developer, basically, it is general to recycle the developer remaining on the photoconductor after the transfer step.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a liquid developer in which a solvent component such as a carrier liquid and a developer particle component such as a toner are appropriately adjusted, particularly a liquid developer having a high concentration and a high viscosity. The present invention relates to a wet electrophotography technique using a method, and is conceptually different from a dry electrophotography technique. That is, in dry electrophotography, the electrostatic latent image formed on the photoconductor is developed (visualized) by bringing dry toner into contact with the surface of the photoconductor. Therefore, in this dry electrophotography, the developer that has not been electrostatically attracted to the electrostatic latent image formed on the photoreceptor is dropped into the developer accommodating portion, and is again applied to the photoreceptor by a developing roller or the like. Supplying and recycling does not cause any problems.

On the other hand, in the wet electrophotography of the present invention,
A liquid developer is applied in a thin layer on a developer carrier such as a developing roller or a developing belt, and the thin layer of the liquid developer is brought into contact with the surface of the photoconductor to form an electrostatic latent formed on the photoconductor. The image is being developed. In such a wet electrophotography, the component ratio of the solvent component and the developer particle component of the liquid developer remaining on the developer carrier without contributing to the development of the electrostatic latent image formed on the photoreceptor. However, it has been found that the ratio is different from the component ratio of a start agent composed of a liquid developer whose components are appropriately adjusted. This is because a charge is applied by a corona charger to increase the amount of charge of the liquid developer applied in a thin layer on the developer carrier, or an electrostatic latent image of developer particles in the liquid developer is formed. When a developing bias is applied in the developing step in order to promote the adhesion of the developer, the thin layer liquid developer applied on the developer carrier is affected, and the liquid developer on the developer carrier after development is affected. This is because the ratio between the amount of the solvent component of the remaining liquid developer and the amount of the developer particle component changes (the details will be described later).

Therefore, in this wet electrophotography,
The liquid developer remaining on the developer carrier after the developing step is collected, and the collected developer collected from the developer carrier is
When reused as it is as a liquid developer for development, a problem occurs that an image visualized on a photoconductor gradually becomes a deteriorated image. Therefore, in order to recycle the collected developer collected from the developer carrier after the development step without causing any trouble, the solvent component and the developer particle component of the collected developer must be properly mixed. It needs to be readjusted like a conditioned starter. Such a component adjustment of the collected developer is usually performed by detecting the characteristics of the collected developer with a sensor and adjusting the solvent component and the developer particle component so that the characteristics of the collected developer are in an appropriate state. A method of adjusting the ratio is adopted.

However, since the liquid developer used for this type of wet image formation is generally a liquid developer having a high concentration and a high viscosity, it is not easy to detect or measure its characteristics. At present, no simple and effective detection means or measurement means can be found. Even if such a detecting means or a measuring means is provided, it is highly likely that the detecting means or the measuring means is considerably large, and such a detecting means or a measuring means is incorporated in the image forming apparatus. This may lead to an increase in size and cost of the device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the amount of collected developer collected from a developer carrier without installing any special detecting means or measuring means. An object of the present invention is to provide a wet image forming method and apparatus which can adjust the components and reuse the recovered developer.

[0009]

According to one aspect of the present invention, an electrostatic latent image is formed on a latent image carrier based on image data, and a solvent is formed on the developer carrier. Forming a thin layer of the liquid developer in which the component and the developer particle component are adjusted, and bringing the thin layer into contact with the surface of the latent image carrier to visualize the electrostatic latent image. Recovering the residual developer remaining on the developer carrier, re-adjusting the solvent component and the developer particle component of the recovered developer recovered from the developer carrier, and recycling the recovered developer. In the wet image forming method to be reused, the area of the image portion and the area of the non-image portion of the electrostatic latent image formed on the latent image carrier are calculated from the image data, and are contacted with the image portion. The amount of the developer particles and the amount of the solvent consumed and the amount of the solvent consumed in contact with the non-image portion are calculated. And al particular, based on the specification result is characterized in readjusting the developer particle component and the solvent component of the recovered developer.

In the case of adjusting the components of the collected developer collected from the developer carrying member, the usual method is to measure the concentration of the collected developer itself, the amount of solid content, etc., and adjust the components of the collected developer. However, if the consumption characteristics of the developer particles and the solvent of the liquid developer used can be grasped in advance,
It is possible to specify what kind of image is printed and how much developer particles and solvent are consumed. By re-adjusting the recycled developer components based on this specified result and recycling them, the components of the liquid developer used for development can be kept within a certain allowable range without providing special detecting means and measuring means. It is possible to fit in. Therefore,
In this wet image forming method, first, the area of the image portion and the area of the non-image portion of the electrostatic latent image formed on the latent image carrier are calculated from the image data. Next, the amount of developer particles and the amount of solvent consumed in contact with the image area and the amount of solvent consumed in contact with the non-image area are specified from the calculation result. Then, the solvent component and the developer particle component of the recovered developer are readjusted based on the specified result. As described above, by taking into account not only the image portion of the electrostatic latent image formed on the latent image carrier, but also the non-image portion, the consumption amount of the developer particles and the solvent of the liquid developer in the developing process is reduced. Can be estimated more accurately.

According to a second aspect of the present invention, in the wet image forming method of the first aspect, the same amount of developer particles and solvent as the amount consumed in contact with the image area and the non-image area is added to the recovered developer. It is characterized in that the solvent component and the developer particle component of the recovered developer are readjusted to replenish.

In this wet image forming method, the amount of developer particles and the amount of solvent are the same as the amount of developer particles and the amount of solvent consumed by developing the electrostatic latent image formed on the latent image carrier. Is directly replenished to the recovered developer.
Thus, the components and the liquid amount of the liquid developer in the developer circulation system are always kept constant. As a result, it is possible to form an image with stable image quality without causing defective development due to an abnormal component ratio of the liquid developer or an insufficient amount of liquid.

According to a third aspect of the present invention, in the wet image forming method of the first aspect, the solvent component and the developer particle component of the liquid developer consumed in contact with the image portion and the non-image portion, Only the more consumed component is replenished to the recovered developer at a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer, and the recovered developer is The solvent component and the developer particle component are readjusted.

In this wet image forming method, of the amount of developer particles and the amount of solvent consumed by developing the electrostatic latent image formed on the latent image carrier, the larger of the consumption rate is used. Only the components are replenished to the recovered developer at a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer. This makes it possible to adjust the components of the recovered developer to the same level as those of the starter by simply replenishing the recovered developer with a minimum amount of the solvent or the developer particles. In addition, when the consumption rate of the developer particles and the solvent is significantly different, it may be sufficient to prepare only one of the solvent and the developer particles as a replenisher to be replenished to the recovered developer. Simplification and miniaturization are promoted.

According to a fourth aspect of the present invention, there is provided a latent image carrier, a latent image forming means for forming an electrostatic latent image on the latent image carrier based on image data, and a solvent component on the developer carrier. By forming a thin layer of the liquid developer in which the developer particles are adjusted and bringing the thin layer into contact with the surface of the latent image carrier, the electrostatic latent image formed on the surface of the latent image carrier is visualized. Developing means for forming an image;
A residual developer collecting means for collecting the residual developer remaining on the developer carrier after the visualization, and a solvent component and a developer particle component of the recovered developer collected from the developer carrier for recycling. In a wet image forming apparatus comprising a collected developer recycling unit for reusing the collected developer after adjustment, the area of the image portion of the electrostatic latent image formed on the latent image carrier and the non-image portion Calculating means for calculating the area of the image data from the image data, and calculating the amount of developer particles and the amount of solvent consumed in contact with the image area and the amount of solvent consumed in contact with the non-image area. It has a specific means for specifying from the calculation result, and a collected developer component readjustment means for readjusting the solvent component and the developer particle component of the collected developer based on the specified result of the specified means. Things.

In this wet image forming apparatus, first,
The calculating means calculates the area of the image portion and the area of the non-image portion of the electrostatic latent image formed on the latent image carrier from the image data. Next, the specifying unit specifies the amount of the developer particles and the amount of the solvent consumed in contact with the image area and the amount of the solvent consumed in contact with the non-image area from the calculation result of the calculating unit. Then, the solvent component and the developer particle component of the recovered developer are readjusted by the recovered developer component readjustment unit based on the specified result of the specifying unit. By re-adjusting and recycling the components of the recovered developer in this way, the components of the liquid developer used for development can be kept within a certain allowable range without providing any special detection means or measurement means. It becomes possible.

According to a fifth aspect of the present invention, in the wet image forming apparatus of the fourth aspect, a developer tank for storing the liquid developer and a maximum allowable amount of the liquid developer stored in the developer tank are provided. A liquid amount upper limit detection sensor that detects whether or not the amount has reached the amount, and the liquid amount upper limit detection sensor detects that the amount of the liquid developer stored in the developer tank has reached the maximum allowable storage amount. And a readjustment operation control means for stopping the readjustment operation of the collected developer readjustment means at the point of time.

According to a fourth aspect of the present invention, there is provided a wet image forming apparatus comprising:
When the consumption amount of the liquid developer obtained by the above-mentioned specifying means is different from the consumption amount actually consumed for some reason, the solvent component and the developer particle component of the recovered developer are readjusted in order to readjust. The amount of the replenisher replenished to the collected developer is larger than the amount of the liquid developer consumed in the developing process, and the liquid developer contained in the developer tank of the developing device overflows. There is a fear. Therefore,
In this wet image forming apparatus, the liquid amount upper limit detection sensor detects whether or not the liquid developer amount stored in the developer tank has reached the maximum allowable storage amount. When the liquid amount upper limit detection sensor detects that the amount of the liquid developer stored in the developer tank has reached the maximum allowable storage amount, the re-adjustment operation control means performs the recovery operation. The readjustment operation of the developer readjustment means is stopped. This makes it possible to prevent the overflow of the liquid developer contained in the developer tank even if the above-mentioned unexpected situation occurs.

According to a sixth aspect of the present invention, in the wet image forming apparatus of the fourth aspect, a developer tank in which the liquid developer is stored, and a minimum allowable amount of the liquid developer stored in the developer tank is stored. A liquid amount lower limit detection sensor for detecting whether or not the amount has reached the amount, and the liquid amount lower limit detection sensor detects that the liquid developer amount stored in the developer tank has reached the minimum allowable storage amount. Starting agent replenishing means for replenishing the developer tank with a starting agent composed of an appropriate amount of a liquid developer in which the solvent component and the developer particle component are appropriately adjusted at the time when the starting is performed. It is.

According to a fourth aspect of the invention, there is provided a wet image forming apparatus comprising:
When the consumption amount of the liquid developer obtained by the above-mentioned specifying means is different from the consumption amount actually consumed for some reason, the solvent component and the developer particle component of the recovered developer are readjusted in order to readjust. The amount of the replenisher replenished to the recovered developer is smaller than the amount of the liquid developer consumed in the developing process, and the amount of the liquid developer stored in the developer tank of the developing device becomes insufficient. There is a fear. Further, when the wet image forming method of the third aspect is employed, the amount of the liquid developer in the developer tank gradually decreases. As described above, when the amount of the liquid developer is smaller than a certain value, for example, the supply amount of the liquid developer to the application roller that applies the liquid developer to the developer carrier is reduced. There is a problem that the developing ability of the liquid developer thin layer applied on the developer carrying member is reduced, and as a result, image quality is deteriorated. Thus, in this wet image forming apparatus, the liquid amount lower limit detection sensor detects whether or not the amount of the liquid developer stored in the developer tank has reached the minimum allowable storage amount. Then, when the liquid amount lower limit detection sensor detects that the amount of the liquid developer stored in the developer tank has reached the minimum allowable storage amount, the starting agent replenishing means detects the solvent component and The developer tank is replenished with a starter composed of an appropriate amount of a liquid developer in which a developer particle component is appropriately adjusted. As a result, even when the above-described unexpected situation occurs, it is possible to prevent the adverse effect caused by the shortage of the liquid developer contained in the developer tank.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a printer which is a wet image forming apparatus will be described below. First, a schematic configuration of a printer according to the present embodiment will be described with reference to FIG. Around a photoreceptor 1 as a latent image carrier of the printer, a charger 2 as a charging unit, an optical writing unit 3 as an image data writing unit, a developing unit 4 as a developing unit, and a transfer as a recording medium A paper feeding unit 5 as a paper feeding means for the paper 11, a transfer roller 6 as a transferring means, a fixing unit 7 as a fixing means, a paper discharging unit 8 as a paper discharging means for the transfer paper 11,
A photoconductor cleaning unit 9 as a cleaning unit for the photoconductor 1 and a static elimination lamp 10 as a static elimination unit are provided.

In FIG. 1, when a print button (not shown) provided on an operation panel of the printer main body is turned on, the photosensitive member 1 is rotated in a direction indicated by an arrow at a constant speed by driving means such as a motor (not shown). Driven. As a result, first, the surface of the photoconductor 1 is uniformly charged in the dark by the charger 2. Next, writing light is irradiated and imaged on the surface of the photoconductor 1 by the optical writing unit 3 based on the image data. Thus, an electrostatic latent image corresponding to the image data is formed on the surface of the photoconductor 1. The image data is written by the writing control board connected to the optical writing unit 3 upon receiving an exposure start command from a CPU board (described later in detail) for controlling the operation of the printer main body. Sent from the board. Then, the electrostatic latent image formed on the surface of the photoconductor 1 is visualized by the liquid developer 41 supplied from the developing unit 4. This allows
A toner image corresponding to the image data is formed on the surface of the photoconductor 1.

On the other hand, in parallel with such an image forming process, the transfer paper 10 stacked and housed in the paper feed cassette 51 of the paper feed unit 5 is fed by the paper feed roller 52 and the separation roller 5.
3, only one sheet is separated and fed, and waits while being held between the pair of registration rollers 54. And the photoconductor 1
The timing at which the leading edge of the toner image visualized on the surface of the transfer paper 10 and the leading edge of the image forming area of the transfer paper 10 sandwiched between the registration rollers 54 match at the nip portion between the photosensitive member 1 and the transfer roller 6 Then, the transfer paper 10 is conveyed toward the nip by the registration rollers 54. As a result, the transfer paper 10 passes through the nip between the photoconductor 1 and the transfer roller 6, and the toner image visualized on the surface of the photoconductor 1 at the nip is transferred onto the transfer paper 10.

The transfer paper 11 onto which the toner image has been transferred in this manner is subjected to a fixing process of the toner image by the fixing unit 7 and then is discharged onto a discharge tray 82 by the discharge rollers 81 of the discharge unit 8. The paper is ejected. Further, in the toner image transfer step, the photoconductor 1
The residual developer remaining on the photoconductor 1 is removed from the photoconductor 1 by the photoconductor cleaning unit 9. Then, the photoconductor 1
The residual potential of the surface is removed by the charge removing lamp 10 to prepare for the next image formation.

Next, the developing unit 4 of the Punter will be described with reference to FIG. This developing unit 4
Developing belt 42 as developer carrier, developer tank 4
3, a developer application roller 44, a layer thickness regulating roller 45, a cleaning blade 46, a developer collection tank 47, a corona charger 48, a bias roller 49, and the like. Although the developing unit 4 uses the developing belt 42 as a developer carrier, the developer carrier is not limited to the developing belt 42, and may be, for example, a developing roller. 2, the developing belt 42 is rotatably stretched by a plurality of rollers including a bias roller 49, and is driven to rotate in a direction indicated by an arrow by driving means (not shown). Further, the developing belt 42 is a portion that is stretched around the bias roller 49,
It is stretched so that its surface contacts the surface of the photoconductor 1.

The developer tank 43 contains a predetermined amount of the liquid developer 41. The liquid developer 41 contained in the developer tank 43 has a relatively high concentration and high viscosity in which a solvent component such as a carrier liquid and a developer particle component such as a toner are adjusted at an appropriate ratio. It is a start agent. The developer application roller 44 is rotatably arranged such that the lower part of the peripheral surface is immersed in the liquid developer 41 accommodated in the developer tank 43 and the upper part of the peripheral surface is in contact with the surface of the developing belt 42. And is driven to rotate in the direction of the arrow by driving means (not shown).

When the developer application roller 44 rotates, the liquid developer 41 stored in the developer tank 43 adheres to the peripheral surface of the developer application roller 44 and is pumped up. The liquid developer 41 attached to the peripheral surface of the developer application roller 44
The liquid amount is regulated by the layer thickness regulating roller 45 to be thinned to a predetermined uniform layer thickness, and the developer thin layer having the uniform layer thickness is applied as it is to the surface of the developing belt 42. . The developer thin layer uniformly applied to the surface of the developing belt 42 in this manner is applied to the corona charger 48.
, The charge amount is increased, and the developer particle component layer and the solvent component layer are separated to some extent. By this separation, a solvent component layer is formed on the developer particle component layer, so that physical adsorption of the developer particles to the non-image portion of the electrostatic latent image formed on the surface of the photoreceptor 1 is avoided. Thus, it is possible to prevent the image transferred to the transfer paper 11 from being soiled.

The thin developer layer charged by the corona charger 48 is applied to the bias roller 4 of the developing belt 42.
9 is in contact with the surface of the photoreceptor 1. Then, by the developing bias applied to the bias roller 49, the developer particles in the developer thin layer are changed to the photosensitive member 1.
Is attracted to the electrostatic latent image formed on the surface of the photoconductor 1, and a toner image is formed on the surface of the photoconductor 1. At this time, in the image portion of the electrostatic latent image formed on the surface of the photoconductor 1, both the solvent component layer and the developer particle component layer of the thin developer layer are adsorbed on the photoconductor 1. On the other hand, in the non-image portion of the electrostatic latent image, as described above, the separating action between the developer particle component layer and the solvent component layer by the corona charger 48 causes the solvent component layer to be formed on the developer particle component layer. Is formed, physical adsorption of the developer particles to the non-image portion is avoided, and the image transferred to the transfer paper 11 is prevented from being soiled. As described above, since the developer component that comes into contact with the non-image portion is not a developer particle component but a solvent component, background contamination of the non-image portion is prevented. When the solvent component layer, which is the surface layer on the developing belt 42, physically contacts the surface of the photoconductor 1, the solvent component of the thin developer layer is slightly carried to the photoconductor side.

For this reason, the residual development which corresponds to the non-image portion of the electrostatic latent image formed on the photoreceptor 1 and does not contribute to the development of the image portion of the electrostatic latent image and remains on the developing belt 42 The component ratio of the solvent component and the developer particle component is different from the component ratio of the start agent whose components are properly adjusted. The residual developer remaining on the developing belt 42 is removed from the surface of the developing belt 42 by the cleaning blade 46, and is collected in a developer collecting tank 47.

As described above, in this type of printer, the recovered developer recovered in the developer recovery tank 47 has a component ratio between the solvent component and the developer particle component.
Since the component ratio of the start agent whose components have been properly adjusted is different, the recovered developer is directly used in the developer tank 43.
When the developer is reused as the liquid developer 41 for development, the amount of the solvent component of the liquid developer 41 in the developer tank 43 becomes insufficient, and the image visualized on the photoreceptor 1 is formed. Has a problem that the image gradually deteriorates.

Therefore, in order to recycle the collected developer collected from the developing belt 42 after the developing step without causing any trouble, the solvent component and the developer particle component of the collected developer must be properly adjusted. It is necessary to readjust like a starter whose components have been adjusted. Such a component adjustment of the collected developer is usually performed by detecting the characteristics of the collected developer with a sensor and adjusting the solvent component and the developer particle component so that the characteristics of the collected developer are in an appropriate state. A method of adjusting the ratio is adopted.

However, since the liquid developer 41 used in this type of printer is a high-concentration and high-viscosity liquid developer as described above, it is not easy to detect or measure its characteristics. At present, no simple and effective detection means or measurement means can be found. Also, even if there is such a detecting means or a measuring means, it is highly likely that the detecting means or the measuring means is considerably large, and by incorporating such a detecting means or a measuring means in a printer, Therefore, there is a possibility that the size of the printer main body and the cost are increased.

When the components of the recovered developer collected from the developing belt 42 are adjusted, a usual method is to measure the concentration of the recovered developer itself, the amount of solid content, and the like to determine the component of the recovered developer. The adjustment will be performed. If the consumption characteristics of the developer particles and the solvent of the liquid developer 41 used as the starting agent can be grasped in advance, the amount of the developer particles when printing what kind of image. And whether the solvent is consumed. If the components of the recovered developer are readjusted and recycled based on the specified result, the components of the liquid developer used in the development can be within a certain allowable range without providing special detecting means and measuring means. It can be stored inside.

Therefore, in the printer according to the present embodiment, first, the area of the image portion and the area of the non-image portion of the electrostatic latent image formed on the photosensitive member 1 are calculated from the image data. Next, the amount of developer particles and the amount of solvent consumed in contact with the image area and the amount of solvent consumed in contact with the non-image area are specified from the calculation result. Then, the solvent component and the developer particle component of the recovered developer are readjusted based on the specified result. As described above, not only the image portion of the electrostatic latent image formed on the photoreceptor 1 but also the non-image portion is taken into consideration, so that the consumption amount of the developer particles and the solvent of the liquid developer 41 in the developing process is reduced. Can be estimated more accurately.

FIG. 3 shows an example of a recovered developer component readjusting means for readjusting the solvent component and the developer particle component of the recovered developer recovered from the developing belt 42. In FIG.
The residual developer remaining on the developing belt 42 is scraped off from the developing belt 42 by a cleaning blade 46 and is collected in a developer collecting tank 47 as a collected developer. Further, in the developer collection tank 47, one or both of the developer particles and the solvent individually housed in a replenishment tank (not shown) are filled with a developer particle replenishing tube 6.
1, and can be replenished as needed through the solvent replenishing tube 62.

The recovered developer recovered in the developer recovery tank 47 is composed of two types of components, that is, developer particles and a solvent, as described above. Therefore, in the developer collection tank 47, the developer particle replenishing tube 61 and the solvent replenishing tube 62 are provided.
By separately replenishing the solvent and the developer particles through the above, the ratio between the solvent component and the developer particle component of the recovered developer can be freely adjusted. Therefore, when the collected developer has accumulated to a certain extent in the developer collection tank 47, the developer particles and the solvent are appropriately distributed into the developer collection tank 47 through the developer particle replenishing pipe 61 and the solvent replenishing pipe 62. Only replenish individually. The timing of replenishment of the developer particles and the solvent may be, for example, every time the number of prints of the printer is counted and the count value reaches a predetermined value, or a liquid amount sensor is provided in the developer collection tank 47. Alternatively, the time may be a time when the liquid amount sensor detects that a predetermined amount of the collected developer is stored in the developer collection tank 47. Then, the collected developer in which the developer particles and the solvent are replenished is transferred to a developer collection tank 47.
The collected developer in the developer collection tank 47 is stirred by a stirring member 63 disposed in the developer tank 43.
Is readjusted to a liquid developer having the same composition as the start agent contained in the liquid developer.

The developer collection tank 47 and the developer tank 43
Are connected by a transport pipe 64 for transporting the collected developer contained in the developer collection tank 47 to the developer tank 43. An electromagnetic three-way valve 65 and a negative pressure pump 66 are provided in the middle of the transport pipe 64. The electromagnetic three-way valve 65 can select whether to conduct between the negative pressure pump 66 and the developer collecting tank 47 or to communicate between the negative pressure pump 66 and the atmosphere. Except during transportation, the air flows between the negative pressure pump 66 and the atmosphere. Then, in the developer collection tank 47,
When a fixed amount or more of the collected developer is accumulated and a predetermined amount of the developer particles and the solvent are replenished, and the readjustment of the components of the collected developer is completed, the electromagnetic three-way valve 65 is set to the negative pressure pump 6
6 and the developer recovery tank 47 are controlled so as to conduct, and the negative pressure pump 66 is operated. Thereby, the collected developer after the component adjustment in the developer collection tank 47 is
The developer is transported to the developer tank 43 through the transport pipe 64 and is recycled as the liquid developer 41 for development.

FIG. 4 shows an example of a control system of the printer. The printer body is controlled by a CPU board 100 which is a main control board. In the CPU board 100,
Sensor 10 for controlling the operation of each unit described above
Various control parts such as a clutch 1, a clutch 102, and a motor 103 are connected, and these control parts are respectively controlled according to a predetermined image forming program to realize an operation as a printer. A writing control board 104 is connected to the CPU board 100, and the writing control board 104 performs the above-described data processing of image data and exposure control (so-called writing control). Since the write control board 104 has a lot of control contents, it is often separate from the main CPU board 100. The write control board 104 sends predetermined image data to the optical writing unit 3 connected to the write control board 104 by receiving an exposure start command from the CPU board 100, and Body 1
Exposure operation is performed.

A host computer 105 is connected to the write control board 104, and the host computer 105 sends the image data to the write control board 104.
Alternatively, the data is stored in an external memory controlled by the write control board 104. Then, the write control board 104
Transmits the image data stored in advance to the optical writing unit 3 in response to an exposure start command from the CPU board 100.

When the image data is transmitted to the optical writing unit 3 in this manner, the product of the area of the image area formed on the photosensitive member 1 and the image density is actually determined by developing the image area. The amount of the developer particles of the liquid developer 41 to be consumed and the amount of the solvent have a certain relationship, and the area of the non-image portion should have the same relationship. Therefore, if the areas of the image area and the non-image area formed on the photoreceptor 1 and the image density are known, the amount of developer particles and the amount of solvent consumed when printing the image can be specified. it can.

That is, in the developing step, of the developer thin layer formed on the developing belt 42, the image portion contains the developer particles and the solvent of the liquid developer 41, and the non-image portion contains only the solvent. Is transferred to the photoconductor 1 side, so that the component ratio between the developer particles and the solvent of the residual developer remaining on the developing belt 42 after this developing step is different from the component ratio of the start agent. This is as described above. Therefore, in the developing step, the developer particles and the solvent of the developer thin layer formed on the developing belt 42
If it is determined in advance how much the electrostatic latent image formed on the photosensitive member 1 is transferred and transferred to the image portion and the non-image portion, the electrostatic latent image formed on the photoconductor 1 can be determined. It is possible to estimate the amount of developer particles and the amount of solvent actually consumed in the developing step. Then, based on the estimated value of the amount of developer particles and the amount of solvent consumed in this developing step, the difference in the component ratio between the developer particles and the solvent of the residual developer remaining on the developing belt 42 after the developing step is determined. , Can be identified with considerable accuracy. Further, the consumption of the developer particles and the consumption of the solvent consumed in the developing step can be calculated by knowing the area and the image density of the image portion and the non-image portion of the electrostatic latent image. Therefore, the information on the area ratio between the image portion and the non-image portion of the electrostatic latent image formed on the photoconductor 1 and the information on the potential of the electrostatic latent image on the photoconductor 1 are derived from the image data. This makes it possible to readjust the components of the recovered developer to a component that can be recycled as a starting agent without detecting or measuring the properties of the recovered developer.

Therefore, in the printer according to the present embodiment, the image data is read by the writing control board 104, and the area of the image portion formed on the photosensitive member 1 from the image data, the image density, Then, the area of the non-image portion is calculated. Then, the area of the image portion and the non-image portion and the calculated value of the image density calculated by the writing control board 104 are transmitted to the CPU board 100. CPU board 100
Based on the received calculated values, by referring to a data table obtained in advance by preliminary experiments,
The amount of the developer particles and the amount of the solvent which are estimated to be consumed by actual image formation are specified. The developer particle amount and the solvent amount may be specified by calculation using a calculation formula obtained in advance by a preliminary experiment, without using the data table as described above.

The developer particles replenished into the developer recovery tank 47 through the developer particle replenishing pipe 61 shown in FIG. 3 based on the consumption of the developer particles and the solvent obtained as described above. The developer replenishment control means 106 for controlling the replenishment amount of the solvent and the solvent replenishment control means 107 for controlling the replenishment amount of the solvent replenished into the developer recovery tank 47 through the solvent replenishment pipe 62 are shown in FIG. Then, control is performed by the CPU board 100. Thereby, the components of the recovered developer are readjusted to the same components as the components of the start agent.

As described above, in this printer, C
By transmitting the calculated values of the area of the image portion and the non-image portion and the image density calculated by the writing control board 104 to the PU board 100, the image data is consumed by actual image formation based on the calculated values. The amount of developer particles and the amount of solvent are specified. Then, the developer particle replenishment control unit 106 is determined based on the specified consumption amounts of the developer particles and the solvent.
Controls the replenishment amount of the developer particles to be replenished into the developer recovery tank 47 through the developer particle replenishment pipe 61, and is controlled by the solvent replenishment control means 107 through the solvent replenishment pipe 62. The replenishing amount of the solvent to be replenished is controlled. Therefore, in the present printer, the components of the collected developer collected in the developer collection tank 47 can be controlled in any manner as long as the control information of the replenishment amount is given to the CPU board 100. . The idea of the present embodiment is to obtain the control information of the replenishment amount from the image data stored in the writing control board 104.

Here, the developer particle replenishment control means 10
6, the replenishment amount of the developer particles to be replenished into the developer collection tank 47 through the developer particle replenishment pipe 61 and the replenishment into the developer collection tank 47 through the solvent replenishment pipe 62 by the solvent replenishment control means 107 The replenishing amount of the solvent to be used is desirably set to the same amount as the amount of the developer particles consumed and the amount of the solvent consumed in the developing step. With this setting, the same amount of developer particles and solvent as the amount of developer particles and the amount of solvent consumed by developing the electrostatic latent image formed on the photoreceptor 1 are collected. The components of the recovered developer are adjusted by being directly replenished to the developer. Thus, the components and the liquid amount of the liquid developer 41 in the developer circulation system of the printer are always kept constant. As a result, it is possible to form an image with stable image quality without causing defective development due to an abnormal component ratio of the liquid developer or an insufficient amount of liquid.

As another method for re-adjusting the solvent component and the developer particle component of the recovered developer, there is a method of contacting an image portion and a non-image portion of an electrostatic latent image formed on the photoreceptor 1. Of the solvent component and the developer particle component of the liquid developer 41 consumed as a result, only the component that has been consumed more is determined by combining the solvent component and the developer particle component in the initial state of the liquid developer 41 with each other. The recovered developer may be replenished at a ratio based on the component ratio (the component ratio of the start agent). Here, the replenishment amount of the developer particles or the solvent to be replenished to the recovered developer is adjusted by adjusting the amount of the excessively consumed component according to a predetermined ratio.
Is maintained in the same manner as in the starter.

Thus, the components of the recovered developer can be adjusted to the same level as those of the starter by simply replenishing the recovered developer with a minimum amount of solvent or developer particles. Therefore, in such an adjustment method, for example, when the predicted consumption amount of the liquid developer 41 is slightly different from the actual consumption amount, the developer collection tank 47 to the developer tank 4
The excess recovered developer is transported to the developer tank 43
The liquid developer 41 in the inside does not overflow. When the consumption rates of the developer particles and the solvent are remarkably different, only one of the solvent and the developer particles may be prepared as a replenisher for replenishing the collected developer. That is, if the excessively consumed component is fixed to one component in any image, a replenisher for only one component may be prepared as a replenisher. In this case, simplification and downsizing of the printer can be promoted.

In the above-mentioned printer, when the consumption of the liquid developer 41 in the developing step obtained by the above calculation is different from the consumption actually consumed for some reason, the collected developer is used. The amount of the replenisher replenished to the recovered developer in order to readjust the solvent component and the developer particle component is greater than the amount of the liquid developer 41 consumed in the developing process.
And the liquid developer 41 contained in the developer tank 43 may overflow. Therefore, in the printer according to the present embodiment, as shown in FIG. 3, the amount of the liquid developer 41 stored in the developer tank 43 is stored in the developer tank 43 in which the liquid developer 41 is stored. A liquid amount upper limit detection sensor 108 for detecting whether the maximum allowable storage amount has been reached is provided, and the liquid amount upper limit detection sensor 108 causes the liquid developer amount stored in the developer tank to reach the maximum allowable storage amount. At the point in time when it is detected that the state has been reached, the readjustment operation of the collected developer readjustment means is stopped.

In this printer, the liquid amount upper limit detection sensor 108 detects whether or not the storage amount of the liquid developer 41 stored in the developer tank 43 has reached the maximum allowable storage amount. When the liquid amount upper limit detection sensor 108 detects that the amount of the liquid developer 41 stored in the developer tank 43 has reached the maximum allowable amount, the liquid amount upper limit is detected. Sensor 1
08 is transmitted to the CPU board 100,
The readjustment operation of the collected developer readjustment means is stopped.
Thus, even when the above-described unexpected situation occurs, it is possible to prevent the overflow of the liquid developer 41 contained in the developer tank 43 beforehand.

The liquid amount upper limit detection sensor 108 includes:
When the viscosity of the liquid developer 41 accommodated in the developer tank 43 is relatively low, an optical sensor that measures the transmitted light intensity of the liquid developer 41 or a liquid level is detected by floating a float. It is preferable to use a float switch. When the viscosity of the liquid developer 41 contained in the developer tank 43 is relatively high and it is difficult to install the optical sensor and the float switch as described above, the weight of the developer tank 43 itself is reduced. May be measured, and based on the measured value, it may be determined whether or not the storage amount of the liquid developer 41 stored in the developer tank 43 has reached the maximum allowable storage amount.

Here, as described above, the developer particle replenishment control means 106 controls the developer particle replenishment tube 61.
The replenishment amount of the developer particles replenished into the developer collection tank 47 through the solvent supply control unit 107 and the replenishment amount of the solvent replenished into the developer collection tank 47 through the solvent replenishment pipe 62 by the solvent replenishment control unit 107 are determined by the development If the consumption amount of the developer particles and the consumption amount of the solvent consumed in the process are set to the same amount, there is a possibility that the liquid developer 41 in the developer tank 43 overflows due to a slight deviation of the predicted consumption value. Therefore, when the liquid amount upper limit detection sensor 108 is activated, the replenishment of the developer particles and the solvent is immediately stopped. Further, as described above, of the solvent component and the developer particle component of the liquid developer 41 consumed in contact with the image portion and the non-image portion of the electrostatic latent image formed on the photoconductor 1, Only the more consumed component is replenished to the recovered developer at a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer 41 (the component ratio of the start agent). Even in the case where the replenishment amount of the replenisher becomes excessive due to some error, the liquid developer 4
Since it cannot be said that there is no possibility that 1 overflows, the liquid amount upper limit detection sensor 108 is useful.

On the other hand, the consumption amount of the liquid developer 41 in the developing step obtained by the above calculation differs from the consumption amount actually consumed for some reason, and the solvent component and the developer particle component of the collected developer are different from each other. If the amount of the replenisher replenished to the collected developer to readjust the amount becomes smaller than the amount of the liquid developer 41 consumed in the developing step, the replenisher is stored in the developer tank 43. There is a possibility that the used liquid developer 41 becomes insufficient. In particular, more of the solvent component and developer particle component of the liquid developer 41 consumed in contact with the image portion and the non-image portion of the electrostatic latent image formed on the photoreceptor 1 were consumed more. Only the other component is replenished to the recovered developer at a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer 41 (the component ratio of the start agent). In this case, the capacity of the liquid developer 41 in the developer tank 43 is gradually reduced.

As described above, when the storage amount of the liquid developer 41 stored in the developer tank 43 becomes smaller than a certain value, for example, the liquid developer 1 is applied to the developing belt 42. Since the supply amount of the liquid developer 41 to the developer applying roller 44 is reduced, the developing ability of the liquid developer thin layer applied on the developing belt 42 is reduced, and as a result, the image quality is deteriorated. Causes malfunction.
In a severe case, the image is not printed at all.

Therefore, in this printer, as shown in FIG. 5, whether or not the storage amount of the liquid developer 41 has reached the minimum allowable storage amount in the developer tank 43 storing the liquid developer 41 is determined. Liquid lower limit detection sensor 109 for detecting
Is provided. Further, a starting agent 1 comprising an appropriate amount of a liquid developer in which the solvent component and the developer particle component are appropriately adjusted.
A start agent tank 111 containing therein 10 is provided, and the start agent tank 111 and the developer tank 43 are connected by a transport pipe 112. Further, in the middle of the transport pipe 112,
An electromagnetic three-way valve 113 and a negative pressure pump 114 are installed. When the liquid amount lower limit detection sensor 109 detects that the storage amount of the liquid developer 41 stored in the developer tank 43 has reached the minimum allowable storage amount, the negative pressure pump 114 The electromagnetic three-way valve 113 is controlled so as to establish electrical connection between the
4 is operated to transport the start agent 110 stored in the start agent tank 111 to the developer tank 43 through the transport pipe 112. As a result, even in the case where the above-described unexpected situation occurs, it is possible to prevent the adverse effect caused by the shortage of the liquid developer 41 contained in the developer tank 43 beforehand. Also,
As a result, normal image printing can be continued.

As the liquid amount lower limit detection sensor 109, an optical sensor or a float switch can be used similarly to the liquid amount upper limit detection sensor 108. When it is difficult to install such an optical sensor or a float switch, the weight of the developer tank 43 itself is measured, and the liquid developer stored in the developer tank 43 is measured based on the measured value. It may be determined whether or not the capacity of the agent 41 has reached the minimum allowable capacity.

As described above, the developer particle replenishment control means 106 controls the replenishment amount of the developer particles to be replenished into the developer collection tank 47 through the developer particle replenishment pipe 61 and the solvent replenishment control means. 107, when the replenishing amount of the solvent to be replenished into the developer collecting tank 47 through the solvent replenishing pipe 62 is set to the same amount as the developer particle consumption amount and the solvent consumption amount consumed in the developing step. In this case, the liquid developer 41 in the developer tank 43 may decrease due to a slight deviation of the predicted consumption value.

[0057]

According to the present invention, the consumption characteristics of the developer particles and the solvent of the liquid developer are grasped in advance,
Since it is possible to estimate how much developer particles and solvent will be consumed when printing what kind of image, a special adjustment can be made by re-adjusting the components of the recovered developer based on this estimation and recycling. The components of the liquid developer used for development can be kept within a certain allowable range without providing a detecting unit or a measuring unit. Further, by taking into account not only the image portion of the electrostatic latent image formed on the latent image carrier but also the non-image portion, the consumption of the developer particles and the solvent of the liquid developer in the developing process can be reduced. There is an excellent effect that it is possible to accurately guess.

In particular, according to the second aspect of the invention, the amount of developer particles consumed by developing the electrostatic latent image formed on the latent image carrier and the amount of solvent are the same as the amount of solvent. And the solvent is directly replenished to the recovered developer, so that when the recovered developer is recycled, the components and the liquid amount of the liquid developer used for development are kept constant, and the There is an excellent effect that an image can be formed with stable image quality without developing failure due to a component failure of the agent or an insufficient amount of liquid.

According to the third aspect of the present invention, the consumption rate of the developer particles and the solvent consumed by developing the electrostatic latent image formed on the latent image carrier is large. Only one component is in a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer,
The collected developer is replenished. This makes it possible to adjust the components of the recovered developer to the same level as those of the starter by simply replenishing the recovered developer with a minimum amount of the solvent or the developer particles. In addition, when the consumption rate of the developer particles and the solvent is significantly different, it may be sufficient to prepare only one of the solvent and the developer particles as a replenisher to be replenished to the recovered developer. There is an excellent effect that simplification and downsizing of the device can be promoted.

According to the fourth aspect of the present invention, the recovered developer component readjustment means re-adjusts the solvent component and the developer particle component of the recovered developer based on the calculation result of the calculation means. In addition, there is an excellent effect that the components of the liquid developer used for development can be kept within a certain allowable range without providing any special detecting means or measuring means.

In particular, according to the invention of claim 5, when the liquid amount upper limit detecting sensor detects that the amount of the liquid developer stored in the developer tank has reached the maximum allowable storage amount, Since the readjustment operation of the collected developer readjustment means is stopped by the readjustment operation control means, the excellent effect that the overflow of the liquid developer contained in the developer tank can be prevented can be prevented. is there.

According to the sixth aspect of the present invention, when the liquid amount lower limit detection sensor detects that the amount of the liquid developer stored in the developer tank has reached the minimum allowable storage amount, By the start agent replenishing means, a start agent composed of an appropriate amount of liquid developer in which a solvent component and a developer particle component are appropriately adjusted is replenished into the developer tank,
There is an excellent effect that an adverse effect due to a shortage of the liquid developer contained in the developer tank can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a printer according to an embodiment.

FIG. 2 is a schematic configuration diagram of a developing unit in the printer.

FIG. 3 is a schematic configuration diagram of a collected developer component readjustment unit for readjusting a solvent component and a developer particle component of the collected developer collected from a developing belt of a developing unit.

FIG. 4 is a block diagram illustrating an example of a control system of the printer.

FIG. 5 is another schematic configuration diagram of a developing unit in the printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charger 3 Optical writing unit 4 Developing unit 5 Paper feed unit 6 Transfer roller 7 Fixing unit 8 Paper discharge unit 9 Photoconductor cleaning unit 10 Static elimination lamp 11 Transfer paper 12 Developer separating device 41 Liquid developer 42 Development Belt 43 Developer tank 44 Developer application roller 45 Layer thickness regulating roller 46 Cleaning blade 47 Developer recovery tank 48 Corona charger 49 Bias roller 61 Developer particle refill tube 62 Solvent refill tube 63 Stirrer 64, 112 Transport tube 65, 113 Electromagnetic three-way valve 66, 114 Negative pressure pump 100 CPU board 104 Writing control board 105 Host computer 106 Developer particle replenishment control means 107 Solvent replenishment control means 108 Liquid upper limit detection sensor 109 Liquid lower limit detection sensor 110 Starter 1 11 Starter tank

Claims (6)

[Claims] An electrostatic latent image is formed on a latent image carrier based on image data, and a thin layer of a liquid developer in which a solvent component and a developer particle component are adjusted is formed on the developer carrier. Then, after the electrostatic latent image is visualized by bringing the thin layer into contact with the surface of the latent image carrier, the residual developer remaining on the developer carrier is recovered, and the developer carrier is collected. In the wet image forming method in which the solvent component and the developer particle component of the recovered developer collected from above are readjusted, and the recovered developer is recycled and reused, the latent image carrier is formed on the latent image carrier. The area of the image area and the area of the non-image area of the electrostatic latent image are calculated from the image data, and the amount of developer particles and the amount of the solvent consumed in contact with the image area and the amount of the solvent in contact with the non-image area are consumed. The amount of solvent to be used is specified from the calculation result, and the solvent component of the recovered developer and the A wet image forming method comprising re-adjusting an image agent particle component. 2. The wet image forming method according to claim 1, wherein the same amount of developer particles and solvent as the amount consumed in contact with the image area and the non-image area is replenished to the recovered developer. A wet image forming method, wherein a solvent component and a developer particle component of the recovered developer are readjusted. 3. The liquid image forming method according to claim 1, wherein more of the solvent component and developer particle component of the liquid developer consumed in contact with the image area and the non-image area are consumed. Only the other component is replenished to the recovered developer at a ratio based on the component ratio of the solvent component and the developer particle component in the initial state of the liquid developer, and the solvent component of the recovered developer and the developer are replenished. A wet image forming method, comprising re-adjusting a particle component. 4. A latent image carrier, a latent image forming means for forming an electrostatic latent image on the latent image carrier based on image data, a solvent component and a developer particle component on a developer carrier. Developing means for forming a thin layer of the liquid developer adjusted to have an electrostatic latent image formed on the surface of the latent image carrier by bringing the thin layer into contact with the surface of the latent image carrier. And a residual developer recovery unit that recovers the residual developer remaining on the developer carrier after the visualization, a solvent component and a developer particle component of the recovered developer recovered from the developer carrier. And a collected developer recycling unit that reuses the collected developer after re-adjusting the image forming apparatus. Calculating means for calculating the area of the image portion from the image data; Specifying means for determining the amount of the developer particles and the amount of solvent and the amount of solvent consumed in contact with the non-image portion from the calculation result of the calculating means; and a solvent component of the recovered developer based on the specification result of the specifying means. And a recovered developer component readjustment unit for readjusting the developer and the developer particle component. 5. The wet image forming apparatus according to claim 4, wherein a developer tank in which the liquid developer is stored, and whether an amount of the liquid developer stored in the developer tank reaches a maximum allowable storage amount. The liquid amount upper limit detection sensor for detecting whether or not the liquid amount upper limit detection sensor detects that the liquid developer amount stored in the developer tank has reached the maximum allowable storage amount. And a readjustment operation control means for stopping the readjustment operation of the collected developer readjustment means. 6. A wet image forming apparatus according to claim 4, wherein a developer tank in which said liquid developer is stored, and whether an amount of liquid developer stored in said developer tank has reached a minimum allowable storage amount. A liquid lower limit detection sensor for detecting whether or not the liquid developer lower limit detection sensor detects that the liquid developer amount stored in the developer tank has reached the minimum allowable storage amount. A wet image forming apparatus comprising: a start agent replenishing means for replenishing the developer tank with a proper amount of a liquid developer in which a solvent component and a developer particle component are appropriately adjusted.