JP2001125385A - Liquid concentration detecting device and liquid level detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid concentration detecting device and a liquid level detecting device capable of preventing the faulty regulation of developer by a metering blade by preventing a liquid carrying roller from reversely rotating when moving operation is performed. SOLUTION: When a gear 8 for a liquid carrying roller is moved downward and the addendum part of the gear 8 abuts on and is meshed with the addendum part of a driving gear 9, force to rotate the gear 9 in a direction shown by an arrow H acts on the gear 9. Then, a roller 63 incorporated in a Torinton clutch 61 is separated from the cam surface 62a of an outer ring 62 and idly rotates, whereby the outer ring 62 gets in a free state. The gear 9 also gets in the free state and idly rotates, so that the gear 8 and the liquid carrying roller 3 rotating integrally with the gear 8 are prevented from totating in a reverse direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid concentration detecting device and a liquid level detecting device used in a wet developing device such as a copying machine, a facsimile, a printer, and the like. The present invention relates to a liquid concentration detecting device and a liquid level detecting device.

[0002]

2. Description of the Related Art Conventionally, a latent image is developed using a liquid developer (hereinafter referred to as a developer) in which a toner as a solid component is dispersed in a liquid solvent as a carrier, and a toner image is formed on the surface of a transfer material. Various image forming apparatuses are known.

As a method for detecting the concentration of a developer in this type of image forming apparatus, for example, a liquid film of the developer is formed,
A method of detecting the developer concentration of the liquid film with a transmission type or reflection type optical sensor has been studied. In this detection method, the light emitted from the light emitting unit passes through the liquid film,
The light transmitted through the liquid film is received by the light receiving unit, and a detection value corresponding to the received light amount is output. Therefore, there is a characteristic that the output decreases as the developer concentration increases. In addition, the sensor output changes following the film thickness of the developing solution, but the sensor output shows a saturation characteristic in the thin film portion and the thick film portion, and the sensitivity may be lowered. If the film thickness of the developing solution is formed so that the optical sensor does not show the saturation characteristic, the detection is performed in the high sensitivity region of the optical sensor, and the detection can be performed with high accuracy. However, even with the same developing solution, the viscosity and the like of the developing solution change due to changes in the environment such as temperature and humidity and changes over time, so that it is very difficult to always form the developing solution to a predetermined constant film thickness.

Accordingly, the present applicant has filed Japanese Patent Application No. 11-529.
In No. 48, in order to detect a wide range of liquid concentration using an optical sensor, a predetermined constant film thickness is not formed, but based on the output of the optical sensor for a plurality of different thicknesses of the liquid to be detected. A method for detecting the concentration of the solution was proposed.

A liquid concentration detecting apparatus to which this detecting method is applied has a schematic structure as shown in FIG. 11, for example.
A liquid carrying roller 3 having an eccentric disk portion 2 sandwiched between two disk portions 1 having the same diameter; a metering blade 4 which abuts on the liquid carrying roller 3 to form a liquid thin layer; It mainly comprises an optical sensor 5 for detecting optical characteristics and a cleaning blade 6 for scraping and cleaning the liquid thin layer.

Then, the liquid carrying roller 3 is partially immersed in the developing solution 7 and rotated, and the density is detected in the circumferential concave portion 3a formed at the step between the eccentric disk portion 2 and the two disk portions 1. The target developer 7 is filled, and the developer 7 is formed into a plurality of different film thicknesses corresponding to the concave portions 3a. Optical sensor 5
The light emitted from the light emitting portion is applied to the developer liquid film formed in the concave portion 3a. The light applied to the developer liquid film is
The light passes through the developer liquid film and is reflected by the outer peripheral side surface of the eccentric disk portion 2. The reflected light is received by the light receiving section of the optical sensor 5, and an analog value corresponding to the intensity of the reflected light is output. While rotating the liquid carrying roller 3 in the direction of arrow A, the optical sensor 5 continuously outputs the developer liquid film of the plurality of thicknesses.
By integrating the analog value of, and comparing it with a value obtained in advance, the developer concentration can be detected.

Here, since the liquid carrying roller 3 needs to pump up the developing solution 7, the lower end of the eccentric disk portion 2 must always be located below the level of the developing solution 7 during the liquid concentration detecting operation. Must. In addition, the metering blade 4 must not be buried in the developing solution 7 because of its function. When the metering blade 4 is buried in the developer 7, the developer 7 adheres to the tip of the metering blade 4. If the liquid concentration detection is performed in this state, a defective regulation occurs due to the effect of the developer 7 attached to the tip of the metering blade 4, a desired film thickness is not formed, and the liquid concentration can be accurately detected. Will be gone.

Therefore, it is required that fluctuations in the liquid level of the developer 7 be controlled between the lower end of the eccentric disk portion 2 and the lower side of the metering blade 4. If the diameters of the disk portion 1 and the eccentric disk portion 2 are increased, the fluctuation of the liquid level of the developer 7 can be increased. However, there is a problem that the device becomes large. In addition, during maintenance other than the developing operation, other containers (for example, a developing unit)
In a configuration in which the developer 7 is once collected in a container in which the liquid carrying roller 3 is disposed, the liquid level of the container may rise and the metering blade 4 may be buried. Therefore, it is necessary to increase the diameter of the disk portion 1 and the eccentric disk portion 2 or to perform a retreat operation with respect to the liquid level.

From the above request, a structure has been developed in which upward movement is performed as a retreat operation. The drive transmission unit having this structure includes a drive gear for transmitting a driving force from a drive source, and a gear for a liquid carrying roller for driving the liquid carrying roller 3. When detecting the liquid concentration, these gears mesh with each other to rotate the liquid carrying roller 3.
When the liquid carrying roller 3 and the metering blade 4 are retracted upward, these two gears are disengaged from each other.

[0010]

In the above structure, FIG.
When the liquid carrying roller 3 and the metering blade 4 are retracted in the direction of the arrow C, as shown in FIG. 3, the liquid carrying roller gear 8 rotating integrally with the liquid carrying roller 3 and the drive gear 9 are separated from each other. When the gear 8 for the liquid carrying roller is
Rotate in the direction. This is because the drive gear 9 is provided with a motor (not shown) on the speed increasing side, so that a large rotation torque is required to rotate it, whereas the gear 8 for the liquid carrying roller has a relatively small rotation torque. It is because it rotates with. Since the rotation direction is the normal rotation direction of the liquid carrying roller 3,
The developer 7 existing near the metering blade 4 of the liquid carrying roller 3 moves downstream with rotation.

On the other hand, when the retracting operation of the liquid carrying roller 3 is released and the liquid carrying roller 3 is returned to the original position, the gear 8 for the liquid carrying roller moves in the downward direction of arrow D, and the tip of the gear The portion abuts and meshes with the tip of the drive gear 9. At this time, as described above, the liquid carrying roller gear 8 rotates in the direction opposite to the arrow B direction due to the magnitude of the rotational torque as described above. When the gear 8 for the liquid carrying roller rotates in the reverse direction, the liquid carrying roller 3 also rotates in the reverse direction, and the developer 7 adheres to the tip of the metering blade 4 as shown in FIG. After that, the image forming operation is restarted, and the liquid carrying roller 3 is rotated in the normal rotation direction, which is the direction of arrow A, with the developer 7 attached to the tip of the metering blade 4 to detect the liquid concentration. As shown in FIG.
As a result, the desired film thickness is not formed, and the liquid concentration cannot be accurately detected.

When the drive gear 9 is disposed on the right side, opposite to the gear 8 for the liquid carrying roller in FIG.
When the liquid bearing roller gear 8 comes into contact with the liquid bearing roller gear 8, the above problem does not occur because the liquid bearing roller gear 8 rotates in the normal rotation direction. However, when the driving gear 9 and the liquid carrying roller gear 8 are separated from each other by the retreating operation, the liquid carrying roller gear 8 rotates in the reverse direction, and the developing solution 7
Adheres, causing a similar problem.

The above-mentioned problem is caused not only by forming a liquid film having a plurality of different thicknesses from the liquid to be detected and detecting the liquid film with an optical sensor. The same problem arises when a predetermined constant film thickness is formed by regulating the developing solution carried on the film by a layer thickness regulating member, and this film thickness is detected by an optical sensor.

The present invention has been made in view of the above background, and an object of the present invention is to prevent the liquid carrying roller from rotating in the reverse direction when performing the above-mentioned moving operation, and to prevent the developer from being supplied by the metering blade. It is an object of the present invention to provide a liquid concentration detecting device and a liquid level detecting device capable of preventing a regulation failure.

[0015]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a liquid holding member for holding a liquid whose concentration is to be detected, and a layer thickness of the liquid held by the liquid holding member. A layer thickness regulating member that regulates and reduces the thickness, and a driving force transmitting unit that transmits a rotational driving force in a predetermined direction to the liquid carrying member, and is carried by the liquid carrying member as data for detecting a liquid concentration. In the liquid concentration detecting device for detecting the liquid concentration using the output data of the optical sensor regarding the film thickness of the liquid, a retreat position where the liquid carrying member and the layer thickness regulating member are retracted from the developer liquid surface and the liquid concentration detection Moving means for moving the liquid carrying member by the moving means, the predetermined direction from the driving force transmitting member on the driving source side of the driving force transmitting means generated in accordance with the movement of the liquid carrying member by the moving means. Driving force in the opposite direction is not transmitted to the liquid carrying member. It is characterized in that constitute the drive force transmission means.

In the liquid concentration detecting device according to the first aspect, the predetermined direction from the driving force transmitting member on the driving source side of the driving force transmitting means, which is generated as the liquid carrying member is moved by the moving means, Since the reverse driving force is not transmitted to the liquid carrying member, the liquid carrying member does not rotate in the reverse direction. Accordingly, it is possible to prevent the liquid from adhering to the tip portion of the layer thickness regulating member caused by the rotation of the liquid carrying member in the opposite direction, and to prevent the regulation failure of the layer thickness regulating member.

According to a second aspect of the present invention, in the liquid concentration detecting device of the first aspect, the driving force transmitting member includes a one-way clutch for transmitting the driving force in the predetermined direction to the liquid carrying member. It is a feature.

In the liquid concentration detecting device according to the second aspect, the driving force transmitting member transmits the driving force in the predetermined direction to the liquid carrying member by the one-way clutch, but the driving force in a direction opposite to the predetermined direction is transmitted. Since no force is transmitted to the liquid carrying member, the liquid carrying member does not rotate in the opposite direction.

According to a third aspect of the present invention, there is provided the liquid concentration detecting device according to the first or second aspect, further comprising a developer adjusting container for accommodating the developer to be detected, and supplying the developer to the developer adjusting container. The moving operation of the moving means is performed in conjunction with the attaching / detaching operation of the toner container for performing the above operation.

In the liquid concentration detecting device according to the third aspect, the moving operation between the liquid carrying member and the layer thickness regulating member is performed in conjunction with the attaching / detaching operation of the toner container, so that the operability is improved.

According to a fourth aspect of the present invention, there is provided a liquid level detecting device for detecting a liquid level of a developer, the liquid level detecting member having an outer peripheral surface whose distance from a rotation center changes, and the liquid level detecting member. A cleaning blade for cleaning the outer peripheral surface of the detecting member, a driving force transmitting unit for transmitting a rotational driving force to the liquid level detecting member, and a detecting unit for detecting a range of the developer adhering to the outer peripheral surface of the liquid level detecting member And characterized in that:

In the liquid level detecting device according to the present invention, when the liquid level of the developing solution is between the outer peripheral portion of the maximum distance from the center of rotation of the liquid level detecting member and the outer peripheral portion of the minimum distance, the rotational movement is performed. The range of the developer adhered to the outer peripheral surface of the liquid level detecting member is detected by the detecting means. Depending on the detected range of the developing solution, it is possible to continuously detect the position of the liquid level of the developing solution. That is, if the detection range of the developer is wide, it indicates that the liquid level is above, and conversely, if it is narrow, it indicates that it is below.

According to a fifth aspect of the present invention, there is provided a liquid level detecting device for detecting a liquid level of a developer, wherein a rotatable or swingable liquid level detecting member for detecting an upper limit of the liquid level, A rotatable or swingable liquid level detecting member for detecting the lower limit of the liquid level, a cleaning member for cleaning the detecting portion of the liquid level detecting member for detecting the upper limit, and a cleaning surface for the liquid level detecting member for detecting the lower limit. A driving member for transmitting a rotational or oscillating power to a cleaning member for detecting the upper limit and a liquid level detecting member for detecting the lower limit, and detecting the liquid level detecting member for detecting the upper limit. And an optical sensor for detecting the presence / absence of the developer adhering to the detecting portion of the liquid level detecting member for detecting the lower limit.

In the liquid level detecting device according to the fifth aspect, the developing solution adheres to the detecting portion of the liquid level detecting member for detecting the upper limit and the detecting surface of the liquid level detecting member for detecting the lower limit. Is detected. This makes it possible to determine whether the liquid level is below the lower limit, within an appropriate range, or above the upper limit. That is, when the optical sensor does not detect the adhesion of the developing solution to either the lower limit detecting member or the upper limit detecting member, it means that the liquid level is below the lower limit. When the adhesion of the developer is detected only on the lower limit detecting member, it means that the liquid level is within an appropriate height range. In addition, when the adhesion of the developing solution is detected on both the lower limit detecting member and the upper limit detecting member, it means that the liquid level is higher than the upper limit. In addition, by appropriately setting the vertical position of the liquid level detecting member for detecting the upper limit and the liquid level detecting member for detecting the lower limit, the apparatus can be made larger in size than the liquid level detecting apparatus of claim 4. Without this, the liquid level detection range can be increased.

According to a sixth aspect of the present invention, there is provided the liquid concentration detecting device of the first, second or third aspect, further comprising the liquid level detecting device of the fourth or fifth aspect, wherein the liquid level detecting device is disposed substantially coaxially with the liquid carrying member. A surface detection member is provided.

In the liquid concentration detecting device according to the sixth aspect, the liquid surface detecting member is provided substantially coaxially with the liquid carrying member, so that the liquid surface near the liquid carrying member can be detected.
When the liquid level detecting member and the liquid carrying member are disposed apart from each other, the height of the liquid surface detected by the liquid level detecting member and the liquid level of the liquid carrying member are equal to each other. It may vary depending on the effect of the ripples. On the other hand, by detecting the liquid level in the vicinity of the liquid carrying member, it is possible to suppress the influence of the waving, and to accurately manage the liquid level within a range where the liquid carrying member can normally operate. Becomes Further, the driving source of the liquid level detecting member can be used also as the driving source of the liquid carrying member, and the size of the apparatus can be reduced.

According to a seventh aspect of the present invention, in the liquid concentration detecting apparatus of the sixth aspect, the driving means for moving the liquid carrying member up and down, and the driving means are controlled based on a liquid level detection result of the liquid level detecting apparatus. And control means for performing the operation.

In the liquid concentration detecting device according to the present invention, the liquid carrying member is moved up and down in accordance with the fluctuation of the liquid surface, so as to expand the fluctuation region of the liquid surface where the liquid carrying member can operate normally. Therefore, the size of the device can be reduced.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment in which the present invention is applied to a wet electrophotographic copying machine (hereinafter simply referred to as "copier") as a wet image forming apparatus will be described. First, an outline of the copying machine according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to the present embodiment.

A charging unit 12, a developing unit 13, an intermediate transfer member 14, a photosensitive drum cleaning unit 15, and the like are arranged around a photosensitive drum 11 as a latent image carrier. Further, a transfer roller 17 is provided as a transfer unit for transferring the developed image to a transfer paper 16 as a final transfer material, facing the intermediate transfer body 14.

In the above configuration, the photosensitive drum 11 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 uniformly charged in the dark by the charging unit 12,
The optical writing unit (not shown) irradiates and forms the writing light LB on the basis of the image information to form an electrostatic latent image on the photosensitive drum 1.
1 is formed. Then, the electrostatic latent image is developed by the developing unit 13, and an image is formed on the photosensitive drum 11. The image formed on the photoconductor drum 11 is transferred onto an intermediate transfer body 14 that is driven at the same speed as the photoconductor drum 11. The image on the intermediate transfer body 14 is transferred to a transfer paper 16 transported from a paper feed cassette (not shown) to a transfer unit.
Is transferred by the transfer roller 17. After the transfer, the transfer paper 16 is fixed by a fixing unit (not shown) and is discharged. The developing solution 7 on the photosensitive drum 11 that has not been transferred onto the intermediate transfer body 14 is removed from the photosensitive drum 11 by the photosensitive drum cleaning unit 15. Further, the remaining developer on the intermediate transfer member 14 is removed by an intermediate transfer belt cleaning unit (not shown). After that, the residual potential of the surface of the photosensitive drum 11 is removed by a discharging lamp (not shown) to prepare for the next copy.

As shown in FIG. 1, the developing unit 13 includes a developing section 21, a developing roller 22, and a developer collecting section 2.
3 and a developer accommodating section (hereinafter, referred to as a “developer adjusting section”)
18, a toner bottle 19, and a carrier bottle 20. The developer 7 used in the present embodiment has a viscosity of 100 to 10000 mPa · s and a toner concentration of 5 to 40%.
More specifically, for example, one having a viscosity of 300 mPa · s and a toner concentration of 15% is used.

The developing unit 21 includes a storage tank 24 storing the developer 7, an application roller 25 for applying the developer 7 to the development roller 22, and a pair of screws for supplying the developer 7 to the application roller 25. 26a and 26b, and a regulating blade 27 for regulating the amount of the developer 7 on the surface of the application roller 25 are provided. Storage tank 24 is 100-150c
c can be stored. When the pair of screws 26a and 26b are driven, the liquid level of the developer 7 in the storage tank 24 rises, and the raised portion contacts the application roller 25, so that the developer 7
Supplied to The amount of the developer 7 supplied to the application roller 25 is regulated by the regulating blade 27, and about 30 cc of the developer 7 is applied to the development roller 22 per minute. The developer collecting section 23 mainly includes a scraping roller 28 and a cleaning blade 29, and cleans the developer 7 remaining on the surface of the developing roller 22.

The developing unit 21, the developing roller 22, and the developer collecting unit 23 among the components of the developing unit 13 are provided in one cartridge (encircled by a dashed line in the drawing). Part), the cartridge can be removed from the copier body when maintenance or replacement is performed. When the cartridge is separated from the developing unit 13 and detached from the copying machine main body, the liquid concentration detecting device 31 of the developer adjusting section 18 is previously retracted upward by moving means described later. Then, the transport pump 33 is rotated in the reverse direction to return the developer 7 in the storage tank 24 to the adjustment tank 30, and the storage tank 24 is emptied. Then, a drain cock 35 provided in a pipe section between the transport pump 33 and the storage tank 24 is provided.
Is closed, and the coupling 36 can be detached by releasing the connection. As described above, since the cartridge is removed after the storage tank 24 is emptied, the leakage and disposal of the developer 7 can be prevented.

Next, the developer adjusting section 18 will be described. The developer adjusting section 18 includes an adjusting tank 30 serving as a storage unit storing the developing solution 7, a liquid concentration detecting device 31 for detecting the concentration of the developing solution 7 stored in the adjusting tank 30, and stirring the developing solution 7. A stirrer 32, a transport pump 33 that can rotate forward and reverse to transport the developer 7, and a lid 34 detachably provided on the upper part of the adjustment tank 30.

The liquid concentration detecting device 31 has a moving device that can be retracted upward. This moving device will be described. FIG. 2 is an exploded perspective view showing the moving device. A fixed bracket 41 that supports the entire moving device is fixed to the adjustment tank 30. This fixing bracket 41
Are formed in a pair of convex portions 41a and 41b, respectively.
Is inserted, and the pair of turning arms 42 and 43 are rotatably supported around the pair of projections 41a and 41b. Then, the respective rotation center holes 44a, 45a of the pair of levers 44, 45 are respectively formed in the respective projections 42b, 43b formed on the upper portions of the pair of rotation arms 42, 43.
Is inserted, and a pair of levers 44 and 45 are rotatably supported around these convex portions 42b and 43b.
A handle 46 and a stay 47 for reinforcement are screwed to the pair of levers 44 and 45.

The pair of rotating arms 42 and 43 hold a toner bottle receiver 48 for holding the neck of the toner bottle 19 and the liquid carrying roller 3 in addition to the pair of levers 44 and 45. Roller holding bracket 4 for
9, a pair of connecting brackets 50 for holding the movable bracket 9 vertically.
51, and a pair of U-groove brackets 52, 53 for limiting the rotation of the pair of rotating arms 42, 43 are held.

A pair of protrusions 48a, 4a formed on the upper part of the side surface of the toner bottle receiver 48 which is bent in a U-shape.
8b is inserted into upper long holes 42c and 43c formed in the pair of rotating arms 42 and 43, respectively. A pair of convex portions 48c and 48d formed on the lower side of the side surface are
Upper holes 50a, 51a formed in the pair of connecting brackets 50, 51, respectively, and a pair of rotating arms 42,
43, lower long holes 42d, 43d
And substantially arc-shaped long holes 44b and 45b formed in each of the pair of levers 44 and 45, and upper holes 52 formed in each of the pair of U-groove brackets 52 and 53.
a and 53a.

The pair of U-groove brackets 52, 53
The U-grooves 52b, 53b of the
The pair of pins 41c and 41d formed on the lower side of FIG. Also, a long hole 52c formed in each of the pair of U-groove brackets 52, 53,
A pair of protrusions 41a, 41b formed on the upper side of the fixed bracket 41 are inserted into 53c.

A pair of projections 49a, 49b of the roller holding bracket 49 are inserted into lower holes 50b, 51b formed in the pair of connecting brackets 50, 51, respectively, to support the roller holding bracket 49. It has become. The liquid holding roller 3 is rotatably held by the roller holding bracket 49 by a pair of bearings 54 and 55. A gear 8 for the liquid carrying roller is fitted on the rotation shaft of the liquid carrying roller 3 and meshes with a driving gear 9 rotatably held by a fixed bracket 41 so that the drive is transmitted. .

Next, the operation of retracting the liquid carrying roller 3 upward by the moving device will be described. FIG.
FIG. 3 is a side view of the moving device in a state where the liquid carrying roller 3 is positioned below, as viewed from a direction E in FIG. 2.

When the liquid carrying roller 3 is in a lower position, the lever 44 is in a substantially upright state. As shown in FIG. 3, the substantially arc-shaped long hole 44b of the lever 44 has a rotation center hole 44a corresponding to the distance L1 between the rotation center hole 44a and the end of the long hole 44b in the longitudinal direction of the lever 44. The distance L2 between the end of the long hole 44b and the fan-shaped portion is shorter (L1> L2). As shown in FIG.
Is in the state (L1) where the distance between the rotation center hole 44a and the long hole 44b is the longest. Since the lower convex portion 48c of the toner bottle receiver 48 is inserted into the elongated hole 44b, the toner bottle receiver 48, the connecting bracket 50 which moves upward in conjunction with the toner bottle receiver 48, and the U-groove bracket 52 is the lowermost position. The roller holding bracket 49 supported by the connection bracket 50 and the liquid carrying roller 3 supported by the roller holding bracket 49 are also located at the lowermost position (FIG. 6).
(A)). The U-groove 52b of the U-groove bracket 52 is fitted with the pin 41c of the fixing bracket 41, and stops the turning arm 42 from turning around the projection 41a of the fixing bracket 41 in the direction of the arrow in the figure. are doing.

Then, when the lever 44 is substantially upright,
When the lever 44 is turned in the direction of the arrow in FIG. 3, the lever 44 turns around the protrusion 42 b of the turning arm 42. In FIG. 2, the rotation is centered on FF. With the rotation of the lever 44, as shown in FIG.
Is raised along the elongated hole 44b of the lever 44, and the toner bottle receiver 48 is also raised at the same time. Accordingly, the connection bracket 50 and the U-groove bracket 52 rise, and the roller holding bracket 49 supported by the connection bracket 50 and the liquid carrying roller 3 supported by the roller holding bracket 49 rise ( FIG. 6 (b)). As described above, the lever 44 has a role of converting a rotational motion into a linear motion. When the bracket 52 with the U-shaped groove is raised, the fitting between the U-shaped groove 52b and the pin 41c of the fixed bracket 41 is released, and the locking of the rotation of the rotating arm 42 is released.

FIG. 5 is a side view showing a state where the lever 44 is rotated about 90 degrees in the direction of the arrow in FIG. 4 from the state shown in FIG. When the lever 44 is further rotated from the state shown in FIG. 4, the lever 44 and the rotating arm 42 whose rotation has been locked are
It rotates around 1a. In FIG. 2, the rotation is about GG. With the rotation of the lever 44, FIG.
As shown in FIG.
2. The U-groove bracket 52 and the like rotate about 90 degrees. As a result, the toner bottle 19 becomes substantially horizontal and can be detached upward. At this time, the connection bracket 50 is
As shown in (c), the roller rotates around the roller 56 provided on the fixed bracket 41, and the hole 50b on the lower side of the connection bracket 50 further rises. Accordingly, this hole 5
The roller holding bracket 49 supported by Ob rises, and the liquid carrying roller 3 also rises. In this manner, the liquid carrying roller 3 can be retracted upward from the liquid surface in conjunction with the attachment / detachment of the toner bottle 19.

However, with the retreating operation, the driving gear 9 rotatably supported by the fixed bracket 41 and the gear 8 for the liquid carrying roller, which is the driven side with respect to the driving gear 9, are separated or abutted. At this time, the liquid carrying roller 3 rotates in the reverse direction and the developer 7 adheres to the metering blade 4,
There is a problem that the above-described inconvenience occurs. Therefore,
The liquid concentration detection device 31 according to the present embodiment is characterized in that a driving force transmission control member capable of cutting off the driving force to be in a free state is provided in the driving force transmission unit. Specifically, for example, a one-way clutch is provided.

FIG. 7A is a front view showing a state in which the driving force is transmitted to the liquid carrying roller gear 8 by the driving gear 9 having a one-way clutch built therein. As the one-way clutch, for example, a tollington clutch 61 can be used. The torington clutch 61 mainly includes an outer ring 62 that rotates integrally with the drive gear 9 and a plurality of rollers 63. The torington clutch 61 is disposed on a drive shaft 64 that is driven to rotate by a drive source (not shown). When the drive shaft 64 rotates in the direction of arrow H, a plurality of rollers 63 incorporated in the torington clutch 61 mesh with a cam surface 62 a formed on the inner peripheral surface of the outer ring 62 to be in a locked state and drive the outer ring 62. Since the drive gear 9 is fixed to the outer ring 62, the gear 8 for the liquid carrying roller meshing with the drive gear 9 rotates forward in the direction of arrow A.

Next, the movement of both gears when the liquid carrying roller 3 and the like are retracted upward by the moving device will be described. FIG. 7B is a front view showing the movement of both gears during retreat. The retreat operation is performed after stopping the motor of the driving source. When the retreat operation is performed, the liquid carrying roller gear 8 moves upward with respect to the driving gear 9. At this time, since the drive source is on the speed increasing side with respect to the drive shaft 64 of the drive gear 9, the drive shaft 64 is hard to rotate. Also, Torrington clutch 6
1 is in the locked state, so that the driving gear 9
Is also difficult to rotate. Accordingly, with the upward retreat operation, the liquid carrying roller gear 8 that is easily rotated with respect to the drive gear 9 rotates in the arrow A direction. Since this rotation direction is the normal rotation direction of the liquid carrying roller 3, the developing solution 7 existing near the metering blade 4 of the liquid carrying roller 3 moves downstream, and the developing solution 7 can be prevented from adhering.

Next, the movement of both gears when the retracting operation by the moving device is released and the liquid carrying roller 3 is returned to the original position will be described. FIG. 7C is a front view illustrating a state in which the retracting operation is released, the gear 8 for the liquid carrying roller is moved downward, and meshes with the drive gear 9. When the gear 8 for the liquid-carrying roller moves downward and the tip of the gear 8 for the liquid-carrying roller comes into contact with and meshes with the tip of the drive gear 9, the drive gear 9 is rotated in the direction of arrow H. At the same time, a force for rotating the liquid carrying roller gear 8 in a direction opposite to the normal rotation direction is applied. Here, when a force for rotating the drive gear 9 in the direction of the arrow H acts, the roller 63 incorporated in the torington clutch 61 is separated from the cam surface 62a of the outer ring 62 and idles, and the outer ring 62 is in a free state. Becomes Therefore, it is possible to prevent the driving gear 9 from being in a free state and idling, and to prevent the liquid carrying roller gear 8 from rotating in the reverse direction.

With the structure and operation described above, since the liquid carrying roller 3 does not rotate in the reverse direction with the retreating operation, the developing solution 7 does not adhere to the tip of the metering blade 4 and Can be prevented from occurring. In the present embodiment, the torington clutch 61, which is a one-way clutch, is used as the driving force transmission control member. However, the present invention is not limited to this, and an electromagnetic clutch may be provided to perform electrical control. Good.

[Modification 1] In the first embodiment, the configuration in which the one-way clutch is incorporated in the drive gear 9 has been described. However, the one-way clutch is disposed on the planetary gear, and the sun gear is provided on the drive source side. When the driving force is transmitted, the planetary gear can be freely rotated to transmit the driving force to the liquid holding member gear.

When the liquid carrying member and the layer thickness regulating member are retracted upward from the developer liquid surface, the gear for the liquid carrying member also moves upward, and accordingly, the planetary gear also moves upward. After retreating, when returning to the original position, the one-way clutch locks the planetary gear and locks in that position, the planetary gear and the gear for the liquid holding member are separated, and the liquid holding member is Move down without rotating. In this manner, since the liquid carrying member does not rotate in the reverse direction, it is possible to prevent the liquid from adhering to the layer thickness regulating member. FIG. 8A is a front view of the vicinity of the drive gear according to the present modification. An idle gear 65 is provided as a planetary gear between the drive gear 9 serving as a sun gear and the gear 8 for the liquid carrying roller, and a one-way clutch is built in the idle gear 65.

An idle gear 65 containing a torington clutch 61 as a one-way clutch is supported on a shaft 67 fixed to a rotating arm 66. The rotation arm 66 is rotatably supported by a drive shaft 64 via a bearing 68. When the drive shaft 64 rotates, the drive gear 9 fixed to the drive shaft 64 rotates in the arrow J direction. Drive gear 9
The idle gear 65 meshing with the gear rotates in a free state, and transmits the rotational driving force to the gear 8 for the liquid carrying roller.

Next, the movement of each gear when the liquid carrying roller gear 8 and the like are retracted upward by the moving device will be described. FIG. 8B is a front view showing the movement of each gear during evacuation. When the retreat operation is performed, the liquid carrying roller gear 8 moves upward. At this time, the driving source is the driving gear 9
The drive shaft 64 is hard to rotate since it is on the speed increasing side with respect to the drive shaft 64. Therefore, the drive gear 9 fixed to the drive shaft 64 is also hard to rotate. Since the liquid carrying roller gear 8 is easily rotated with respect to the drive gear 9, when the liquid carrying roller gear 8 moves upward, the liquid carrying roller gear 8 and the idle gear 65 move upward while rotating. . At this time,
Since the idle gear 65 is supported by the rotation arm 66 so that the rotation center distance between the drive gear 9 and the idle gear 65 does not change, the idle gear 65 rotates in the arrow K direction. With the rotation of the idle gear 65, the liquid carrying roller gear 8 rotates in the direction of arrow A. Since this rotation direction is the normal rotation direction of the liquid carrying roller 3, it is present near the metering blade 4 of the liquid carrying roller 3. The developer 7 moved to the downstream side can prevent the developer 7 from adhering to the tip of the metering blade 4.

Next, the movement of each gear when releasing the retracting operation by the moving device and returning the liquid carrying roller 3 to the original position will be described. FIG. 8C is a front view showing a state in which the retracting operation is released and the liquid carrying roller gear 8 is moved downward. The liquid carrying roller gear 8 moves downward, and at the same time, the idle gear 65 also attempts to move downward due to the effect of gravity. Here, in order for the idle gear 65 to move downward, the idle gear 65 must rotate in the opposite direction to the upward movement. However, when the idle gear 65 rotates in this direction, the torington clutch 61 is locked, and the idle gear 65 cannot rotate and cannot move upward. Will remain at Therefore, the gear 8 for the liquid carrying roller is disengaged from the idle gear 65, and moves independently without rotating. The idle gear 65 moves downward as the drive gear 9 rotates, and as shown in FIG.
Will be engaged.

With the structure and operation described above, the liquid carrying roller 3 does not rotate in the reverse direction with the retreating operation, so that the developer 7 does not adhere to the tip of the metering blade 4, The occurrence of the problem can be prevented.

[Second Embodiment] In the first embodiment, the structure for preventing reverse rotation when the liquid carrying roller 3 is retracted upward has been described. However, the structure in which the liquid carrying roller 3 is provided with a liquid level detecting device. It can also be. FIG. 9 is an explanatory view in which a liquid level detecting device is provided on the cylindrical portion of the liquid carrying roller. This liquid level detecting device includes a liquid level detecting member 71 having an outer peripheral surface whose distance from the rotation center changes, and a cleaning blade 72 for cleaning the outer peripheral surface of the liquid level detecting member.
And a reflection-type optical sensor 73.

The liquid level detecting member 71 is provided so as to rotate integrally with the disk portion 1 of the liquid carrying roller 3 in contact with or close to the disk portion 1. When the maximum distance from the center of rotation of the liquid level detecting member 71 to the outer peripheral surface is r1, the minimum distance is r2, and the radius of the disk portion 1 is R, the following relationship is satisfied.

## EQU1 ## 0 ≦ r2 <r1 <R

When the liquid level detecting member 71 is rotated, the developer 7
The developer 7 adheres to the outer peripheral surface of the portion in contact with the developer, and the developer 7 is pumped up. On the other hand, the outer peripheral surface of the portion where the developing solution 7 is not in contact becomes the background. The reflection amount of light differs between the portion where the developer 7 is attached and the background portion where it is not attached. Specifically, the reflected light amount of light is small in the portion where the developing solution 7 is attached, and the reflected light amount is large in the background portion. By detecting the difference in the amount of reflected light with the optical sensor 73, the presence or absence of the developer 7 on the surface of the liquid level detecting member 71 is detected.

As the optical sensor 73, for example, a diffuse reflection type photoelectric switch can be used. And
A threshold value is set to a substantially intermediate value between the reflected light amount of the portion where the developing solution 7 is adhered and the reflected light amount of the background portion, and a detection signal is output when the value falls below the threshold value. When the detection signal is output, it indicates that the portion where the developing solution 7 has been adhered is detected. Therefore, this time is measured by an internal timer such as a controller (not shown) and compared with a value obtained in advance. By doing so, the position of the liquid surface of the developer 7 can be detected. Specifically, when the time during which the detection signal is output is long, the liquid level is above.
On the other hand, when the time during which the detection signal is output is short, the liquid level is below. In this way, the liquid level within the range of the maximum distance r1 and the minimum distance r2 from the rotation center of the liquid level detection member 71 can be continuously detected.

The liquid level detecting member 71 does not necessarily need to be provided in contact with or close to the disk portion 1 of the liquid carrying roller 3. However, by providing the liquid level detecting member 71 in contact with or close to the disk portion 1 and integrating the liquid concentration detecting device and the liquid level detecting device, the liquid level management in the vicinity of the liquid concentration detecting device can be managed. Can be performed with high accuracy,
The device configuration can be simplified.

Further, based on the detection result of the liquid level by the liquid level detecting device, the vertical position of the liquid concentration detecting device automatically follows the liquid surface of the developing solution 7 so that the liquid concentration can be detected. The fluctuation range of the liquid level can be made large, and the size of the liquid carrying roller 3 can be reduced. Here, as a method of automatically following the vertical position of the liquid concentration detecting device to the liquid surface of the developer 7, for example, a straight line is formed in a vertical direction using a screw feed mechanism provided with a drive source such as a stepping motor. There are ways to exercise.

[Modification 2] In the second embodiment, the liquid level detection range cannot be made larger than the maximum distance r1 of the liquid level detection member 71, but may be made larger than the maximum distance r1. . FIG. 10A is an explanatory diagram of a liquid level detection device according to this modification. FIG. 10 (b)
It is the side view seen from the right in the figure of Drawing 10 (a).

The liquid level detecting device according to this modification includes a lower limit detecting member 74 and an upper limit detecting member 75 for the liquid level, and the diameter of the upper limit detecting member 75 is made larger than the radius of the lower limit detecting member 74. It is configured small. Lower limit detection member 7
Numeral 4 is fixed to the drive shaft 64 of the disk unit 1 of the liquid concentration detecting device so as to rotate integrally therewith. Further, a cleaning blade 7 for cleaning both detection members.
6, 77 and an optical sensor 78 are provided. Further, as shown in FIG. 10B, a drive gear 79 fixed to the drive shaft 64, an idle gear 80, and a gear 81 for an upper limit detecting member are provided. The detection member 75 rotates in the same direction.

Then, the optical sensor 78 is formed so that the beam spot of the optical sensor 78 is simultaneously formed on each of the lower limit detecting member 74 and the upper limit detecting member 75.
Is arranged. As the optical sensor 78, an analog output type is used, and an analog value output from the optical sensor 78 is A / D converted by a sensor controller (not shown). By setting two threshold values in this sensor controller, when one optical sensor 78 detects that the liquid level is lower than the lower limit of the lower limit detecting member 74 (insufficient liquid amount), As described above, it is possible to detect the case where the liquid amount is lower than the lower limit of the upper limit detecting member 75 (appropriate liquid amount) and the case where it is equal to or more than the lower limit of the upper limit detecting member 75 (overflow).

The liquid level detecting device having the above configuration can detect two points, that is, the upper limit and the lower limit. Further, by combining with the liquid level detecting device having the configuration of the second embodiment, continuous liquid level detection can be performed. It becomes possible. Also, two switching output type photoelectric switches are provided in place of the analog photoelectric sensor 78, and a lower limit detecting member 74 and an upper limit detecting member 7 are provided.
5 can be detected separately, and two points, the upper limit and the lower limit, can be detected.

[0066]

According to the first, second, third, sixth and seventh aspects of the present invention, since the liquid carrying member does not rotate in the reverse direction, the developing solution does not adhere to the layer thickness regulating member. There is an excellent effect that accurate regulation of the liquid concentration can be performed by preventing the defective regulation of the above.

In particular, according to the third aspect of the present invention, the retracting operation between the liquid carrying member and the layer thickness regulating member is performed in conjunction with the detaching / attaching operation of the toner container, so that the operability is improved. Has an effect.

According to the present invention, the height of the liquid level of the developing solution between the outer peripheral portion of the maximum distance from the center of rotation of the liquid level detecting member and the outer peripheral portion of the minimum distance is continuously detected. There is an excellent effect that can be.

According to the fifth aspect of the invention, there is an excellent effect that the upper limit and the lower limit of the developer can be detected and the liquid level detection range can be increased without increasing the size of the apparatus.

In particular, according to the invention of claim 6, by detecting the liquid level in the vicinity of the liquid concentration detecting device, the influence of the ripple can be suppressed, and the liquid level is set within a range where the liquid carrying member can operate normally. There is an excellent effect that can be managed with high accuracy. In addition, the driving source of the liquid level detecting member can be used also as the driving source of the liquid holding member, and there is an excellent effect that the apparatus can be downsized.

In particular, according to the invention of claim 7, since the fluctuation range of the liquid level at which the liquid carrying member can operate normally can be expanded, an excellent effect that the apparatus can be downsized can be obtained. is there.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part of a wet image forming apparatus according to an embodiment.

FIG. 2 is an exploded perspective view of the moving device.

FIG. 3 is a side view when the moving device is at a height when a liquid concentration is detected.

FIG. 4 is a side view showing a state where the lever is rotated to move a bracket with a U-groove or the like upward along a long hole of the lever;

FIG. 5 is a side view showing a state in which the lever and the like are further turned to make the lever and the like horizontal.

FIGS. 6A, 6B, and 6C are explanatory diagrams showing a state when the liquid carrying member 3 and the like are retracted from the liquid surface.

FIG. 7A is an explanatory view showing a relationship between a gear for a liquid carrying roller and a driving gear when driving force is transmitted. (B) is an explanatory view showing the relationship between the gear for the liquid carrying roller and the drive gear during the retreat operation. (C) is an explanatory view showing the relationship between the liquid carrying roller gear and the drive gear when returning to the original state.

FIGS. 8A, 8B, and 8C are explanatory diagrams showing a relationship among gears according to a modification.

FIG. 9 is an explanatory diagram of a liquid level detection device according to another embodiment.

FIG. 10 is an explanatory diagram of a liquid level detection device according to a modification.

FIG. 11 is an explanatory diagram of a liquid concentration detection device proposed by the present applicant.

FIG. 12 is an explanatory diagram showing a relationship between a gear for a liquid carrying roller and a drive gear of the liquid concentration detecting device proposed by the present applicant.

FIGS. 13A and 13B are diagrams for explaining a defective regulation of the developer when the liquid carrying roller rotates in the reverse direction.

[Explanation of symbols]

 3 Liquid carrying roller 4 Metering blade 8 Liquid carrying roller gear 9 Drive gear 11 Photoconductor drum 13 Developing unit 18 Developer adjusting section 19 Toner bottle 20 Carrier bottle 21 Developing section 22 Developing roller 23 Developer collecting section 31 Liquid concentration detection Device 41 Fixed bracket 42, 43 Rotating arm 44, 45 Lever 49 Roller holding bracket 50, 51 Connection bracket 52, 53 U-groove bracket 56, 57 Roller 61 Torrington clutch 65 Idle gear 66 Rotating arm 71 Liquid level detecting member 73 Optical sensor 74 Lower limit detecting member 75 Upper limit detecting member 78 Optical sensor

Claims (7)

[Claims] A liquid holding member for holding a liquid whose concentration is to be detected, a layer thickness regulating member for regulating the thickness of the liquid carried on the liquid carrying member to reduce the thickness thereof, and Driving force transmitting means for transmitting the rotational driving force in the direction, and detecting the liquid concentration by using output data of an optical sensor regarding the film thickness of the liquid carried on the liquid carrying member as data for detecting the liquid concentration. A moving means for moving the liquid carrying member and the layer thickness regulating member between a retracted position retracted from the developer liquid surface and a detection position at which liquid concentration can be detected; The driving force transmitted from the driving force transmitting member on the driving source side of the driving force transmitting means, which is generated in accordance with the movement of the liquid holding member, is prevented from being transmitted to the liquid holding member. Liquid concentration detection device characterized by comprising force transmission means 2. The liquid concentration detecting device according to claim 1, wherein the driving force transmitting member includes a one-way clutch for transmitting the driving force in the predetermined direction to the liquid carrying member. Detection device. 3. A liquid concentration detecting device according to claim 1, further comprising a developer adjusting container for storing a developing solution to be detected, and a toner for replenishing the developing agent adjusting container. A liquid concentration detecting device, wherein the moving operation of the moving means is performed in conjunction with the demounting operation of the storage container. 4. A liquid level detecting device for detecting a liquid level of a developer, the liquid level detecting member having an outer peripheral surface whose distance from a rotation center changes, and an outer peripheral surface of the liquid surface detecting member A cleaning blade for cleaning the liquid level detecting member, a driving force transmitting means for transmitting a rotational driving force to the liquid level detecting member, and a detecting means for detecting a range of the developer adhering to the outer peripheral surface of the liquid level detecting member. Characteristic liquid level detection device. 5. A liquid level detecting device for detecting a liquid level of a developer, comprising: a rotatable or swingable liquid level detecting member for detecting an upper limit of the liquid level; and a lower limit of the liquid level. A rotatable or swingable liquid level detecting member, a cleaning member for cleaning a detecting portion of the liquid level detecting member for detecting the upper limit, and a cleaning member for cleaning a detecting surface of the liquid level detecting member for detecting the lower limit, A driving force transmitting means for transmitting a rotational force or a oscillating power to a liquid level detecting member for detecting the upper limit and a liquid level detecting member for detecting the lower limit, and a detecting unit of the liquid level detecting member for detecting the upper limit and the lower limit. A liquid level detecting device, comprising: an optical sensor for detecting whether or not the developing solution adheres to a detecting section of the liquid level detecting member to be detected. 6. The liquid concentration detecting device according to claim 1, further comprising the liquid level detecting device according to claim 4, wherein the liquid level detecting member is provided substantially coaxially with the liquid carrying member. A liquid concentration detecting device. 7. A liquid concentration detecting device according to claim 6, wherein said driving means moves up and down said liquid holding member, and said control means controls said driving means based on a liquid level detection result of said liquid level detecting device. A liquid concentration detecting device, comprising: