JP2009175386A - Density measuring device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a density measuring device capable of accurately measuring the density of an object substance in a prescribed liquid while substantially maintaining the fluid state of the prescribed liquid, and to provide an image forming apparatus equipped with the same. <P>SOLUTION: Disclosed are the density measuring device for measuring the density of the object substance in the prescribed liquid and the image forming apparatus equipped with the density measuring device, wherein the density measuring device includes: a tube for feeding the prescribed liquid; a density detecting section being a portion of the tube, elastically deformed to a prescribed thickness with application of external pressure; and an optical measuring device for measuring light-transmittance of the prescribed liquid at the density detecting section that was deformed to the prescribed thickness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a density measuring apparatus and an image forming apparatus, and more particularly to a toner density measuring apparatus capable of accurately measuring a toner density while maintaining a liquid developer or the like in a substantially fluid state and an image forming apparatus including the same. .

Conventionally, a toner concentration measuring device has been proposed in which a thin layer is formed on a predetermined rotating body, and then the light reflectance is measured to measure the toner concentration of the liquid developer.
That is, as shown in FIG. 8, a toner density is provided in which a photosensor 330 is provided as a toner density detecting means, and a cleaning blade 305 that is operated by a driving device (not shown) is provided on the downstream side in the rotation direction of the rotating body 301. This is a measuring device 300.
Then, based on the detection value by the optical sensor 330, a toner density determining means (not shown) for determining the toner density, and data on the variation in toner density are obtained based on a plurality of toner densities from the determining means. A density counting means (not shown) and a control device (not shown) for obtaining variation data from the density counting means and operating the driving device when the density exceeds the specified range are provided. .
In the measurement of the toner density, the rotation of the rotating body 301 causes the liquid developer (toner ink T) to be pumped into the holding groove (not shown) to form a liquid developer layer (Tb). Regarding the agent layer, the optical reflectance is detected by the optical sensor 330, and when the variation of the toner density exceeds the specified range, the liquid developer layer in the holding groove is scraped off by the cleaning blade 305.
JP 2003-345137 A

However, the proposed toner concentration measuring apparatus has a problem in that it is difficult to stably form a thin liquid developer layer depending on the environmental temperature and the type of toner.
For example, when the ambient temperature is relatively high, the viscosity of the liquid developer (sometimes simply referred to as a developer) decreases, and the thickness of the thin layer tends to be thin, whereas the ambient temperature is relatively low. When the viscosity is low, the viscosity of the liquid developer increases, and there is a problem that the thickness of the thin layer becomes thick or unevenness tends to occur.
Further, when the toner or the like easily settles in the liquid developer depending on the type of toner, there is a problem that not only the measured density is correct but also the density unevenness becomes large.
In addition, since the proposed toner concentration measuring apparatus must pump up a predetermined amount of liquid developer by the rotating body, the liquid developer whose concentration can be measured is only on the surface, and the entire liquid developer is measured. There was also a problem that the concentration could not be measured.
In addition, the proposed toner concentration measuring device has a complicated configuration, and the pumping amount of the liquid developer changes greatly due to contamination of the holding groove of the rotating body, so that the concentration measurement cannot be performed more accurately. It was observed.

Accordingly, as a result of intensive studies, the present inventors have provided a predetermined pipe, a predetermined concentration detection unit, and a predetermined light measurement device, thereby substantially bringing a predetermined liquid such as a liquid developer into a fluid state. It was found that the concentration of the target substance in the predetermined liquid can be accurately measured while keeping it.
That is, according to the present invention, even with a simple configuration, a concentration measuring device (toner concentration measuring device) that can extract a part of a predetermined liquid in a fluid state and accurately measure the concentration of a target substance contained therein. It is another object of the present invention to provide an image forming apparatus including such a density measuring device.

According to the present invention, a concentration measuring device for measuring the concentration of a target substance in a predetermined liquid,
Piping for feeding a predetermined liquid;
A part of the pipe is provided with a concentration detector that elastically deforms to a predetermined thickness by applying external pressure,
A concentration measuring device comprising: a light measuring device for measuring the light transmittance of a predetermined liquid at a concentration detecting unit in a state of being deformed to a predetermined thickness. can do.
That is, by providing a predetermined pipe, a predetermined concentration detector, and a predetermined light measurement device, a part of a predetermined liquid such as a liquid developer is extracted in a fluid state to prevent sedimentation of the target substance. However, as a whole, the concentration in the predetermined liquid can be accurately measured.
Moreover, since the take-out position of the predetermined liquid can be arbitrarily adjusted, the concentration of the target substance at the arbitrary position in the predetermined liquid can be accurately measured.
Furthermore, since a special rotating body, a cleaning blade operated by a driving device, and the like are unnecessary, a simple and small concentration measuring device can be provided.
In the concentration detector in a state of being deformed to a predetermined thickness, a part of the flow of the predetermined liquid is obstructed. For example, it is a short time of 5 seconds or less, further 0.5 seconds or less, It has been separately found that such a time does not cause problems such as sedimentation of the target substance.

In configuring the concentration measuring apparatus of the present invention, it is preferable that the concentration detection unit is deformed to a predetermined thickness by a crank as an external pressure.
By comprising in this way, the density | concentration detection part in piping can be deformed to predetermined thickness accurately and automatically. As a result, a part of the predetermined liquid can be extracted in a fluidized state, and the concentration of the target substance can be accurately measured as a whole.

In configuring the concentration measuring apparatus of the present invention, a thickness adjusting member for maintaining the thickness of the concentration detecting unit at a predetermined value is provided inside and / or outside of the concentration detecting unit. It is preferable.
By configuring in this way, the concentration detector in the pipe can be deformed to a predetermined thickness with higher accuracy, and as a result, a part of the liquid developer is extracted in a flowing state, and the concentration as a whole is determined. It can be measured accurately.

Further, in configuring the concentration measuring apparatus of the present invention, it is preferable that the thickness of the concentration detecting unit is made variable by the thickness adjusting member according to the type of the target substance in the predetermined liquid.
By configuring in this way, the detection accuracy of the optical measurement device for a predetermined target substance is improved, and a part of the predetermined liquid is extracted in a flow state, and as a whole, the concentration of the target substance is measured more accurately. Can do.

In configuring the concentration measuring apparatus of the present invention, it is preferable that a flow rate adjusting member for adjusting a predetermined liquid amount in the pipe is provided at the inlet and / or outlet of the pipe.
By configuring in this way, the detection accuracy of the optical measurement device for a predetermined target substance is improved, and a part of the predetermined liquid is extracted in a flow state, and as a whole, the concentration of the target substance is measured more accurately. Can do.

Further, in configuring the concentration measuring device of the present invention, the light measuring device includes a light emitting unit and a light receiving unit, and the light amount change of light emitted from the light emitting unit is measured by the light receiving unit. Therefore, it is preferable to measure the concentration of the target substance.
With this configuration, even when a part of the liquid developer or the like as the predetermined liquid is extracted in a fluid state, the overall concentration can be accurately measured based on a predetermined light measurement device. it can.
That is, when a predetermined liquid is filled in a space of a predetermined distance and light is transmitted through the space, the amount of light reaching the light receiving portion changes according to the concentration of the target substance in the predetermined liquid, The concentration can be measured.
Note that the light emitting unit and the light receiving unit in the light measuring device are provided on the same side with respect to the pipe, and the light emitted from the light emitting part is provided in a part of the pipe after passing through the pipe. It is also preferable to reflect on the reflecting member and measure the concentration of the target substance from the reflected light.
With this configuration, the measurement length of light is doubled. Therefore, even when a part of a predetermined liquid is extracted in a fluid state, the overall concentration is more accurately based on a predetermined light measurement device. Can be measured.
Moreover, since the light-emitting part and the light-receiving part are provided on the same side with respect to the pipe, the size of the light measuring device can be reduced.

In configuring the density measuring apparatus of the present invention, it is preferable to use a toner density measuring apparatus for measuring the toner density in the liquid developer.
With this configuration, it is possible to accurately measure the toner concentration in the liquid developer as a whole while extracting a part of the liquid developer in a fluid state and preventing the toner from being settled.

According to another aspect of the present invention, there is provided an image forming apparatus including a concentration measuring device for measuring the concentration of a target substance in a predetermined liquid, wherein the concentration measuring device sends a predetermined liquid. And a concentration detection unit in which a part of the pipe is elastically deformed to a predetermined thickness by applying external pressure, and the concentration detection unit in a state where the light transmittance of the predetermined liquid is deformed to the predetermined thickness An image forming apparatus comprising: a light measuring device for measuring.
That is, the image forming apparatus includes a concentration measuring device including a predetermined pipe, a predetermined density detecting unit, and a predetermined light measuring device, so that a part of a predetermined liquid such as a liquid developer is in a flow state. As a whole, it is possible to accurately measure the concentration in the predetermined liquid while preventing sedimentation of the target substance.
Further, since the take-out position of the predetermined liquid can be arbitrarily adjusted, the concentration of the target substance at an arbitrary position in the predetermined liquid can also be measured with high accuracy.
Further, since a special rotating body, a cleaning blade operated by a driving device, and the like are unnecessary, a small image forming apparatus including a simple and small density measuring device can be provided.

[First Embodiment]
As illustrated in FIG. 1, the first embodiment is a concentration measuring device 10 for measuring the concentration of a target substance in a predetermined liquid,
A pipe 12 for feeding a predetermined liquid (F);
A part of the pipe 12 includes a concentration detection unit 19 that elastically deforms to a predetermined thickness by application of an external pressure (crank) 20, and
And a light measuring device (22, 24) for measuring the light transmittance of the predetermined liquid (F) in the concentration detector 19 in a state of being deformed to a predetermined thickness. .

Hereinafter, the density measuring apparatus of the present invention will be described as the toner density measuring apparatus 10 with reference to the drawings as appropriate. FIGS. 1A and 1B illustrate the basic operation of the toner density measuring apparatus 10. FIG.
FIGS. 2A to 2C are views for explaining the valve structures 14 and 28 of the toner concentration measuring apparatus 10, and FIGS. 3A to 3D are thickness adjusting members 26. It is a figure provided in order to demonstrate the aspect of.
Further, FIG. 4 is a diagram provided for explaining the light measuring devices 22 and 24 of the toner concentration measuring device 10, and FIGS. 5A and 5B are basic operations of another toner concentration measuring device 100. FIG. 6A to FIG. 6B are views provided to explain another aspect of the thickness adjusting member 102.

1. Piping As shown in FIGS. 1A and 1B, the piping 12 is a part of the toner concentration measuring device 10 and is defined as a portion for feeding the liquid developer to the concentration detecting unit 19. The
Here, an arrow indicates the liquid feeding direction of the liquid developer (F) as the predetermined liquid in the pipe 12, but the pipe 12 is made of a transparent resin or a part of the opaque resin. It is preferable that a light transmitting portion made of a transparent member is provided on the surface.
The reason for this is that if the pipe is made of a transparent resin, a part of the liquid developer is extracted in a fluid state by a predetermined light measurement device regardless of the size of the pipe or the type of the liquid developer. This is because the concentration as a whole can be accurately measured.
Further, even if the pipe is made of an opaque resin, if the light transmission part made of a transparent member is formed in a part of the pipe, the size of the pipe and the liquid can be measured by a predetermined light measuring device. This is because, regardless of the type of developer, a part of the liquid developer can be extracted in a fluid state, and the overall density can be accurately measured.
In addition, when it is necessary to prevent unnecessary incident light from the outside, it is preferable to adopt such a configuration.

Moreover, although it does not restrict | limit especially also about the diameter of piping, For example, it is preferable to set it as the value within the range of 0.1-10 mm.
The reason for this is that when the diameter of the pipe is less than 0.1 mm, the fluid friction of the liquid developer (F) as the predetermined liquid increases, and it may be difficult to obtain a stable fluid state. Because there is. In the case of a predetermined liquid having a high viscosity, for example, a liquid developer having a viscosity of 150 cps (measurement temperature 20 degrees) or more, if the diameter of the pipe is excessively thin, it may be difficult to obtain a stable fluid state. Also, in the case of black toner or the like, since the light absorption is strong, it is necessary to basically reduce the diameter of the pipe. However, when the value is less than 0.1 mm, it has been found that the fluid state is significantly reduced. Yes. Further, when the diameter of the pipe is less than 0.1 mm, the target substance, for example, toner particles contained in the predetermined liquid may be liable to settle excessively.
On the other hand, if the diameter of the pipe exceeds 10 mm, it may be difficult to make the liquid developer (F) as the predetermined liquid into a stable flow state.
Therefore, the diameter of the pipe is more preferably set to a value within the range of 1 to 8 mm, and further preferably set to a value within the range of 2 to 5 mm.
As shown in FIGS. 2A to 2C, the diameter of the pipe is the outer diameter (l1) when the pipe 12 has a circular cross section. It becomes the outer diameter of the equivalent circle diameter.

Moreover, although it does not restrict | limit especially also about the material of piping, For example, it is preferable to make it from resin, such as a polyester resin, a polycarbonate resin, a polyurethane resin, an epoxy resin, an acrylic resin, an olefin resin, a phenol resin.
The reason for this is that by using a pipe made of such a material, excellent transparency and elasticity can be obtained even when various shapes are processed. This is because a part of the liquid developer can be extracted in a fluidized state and the overall density can be accurately measured regardless of the type of the liquid developer.
Further, by using a pipe made of such a material, the fluid friction of the liquid developer (F) as the predetermined liquid is reduced, and a stable flow state can be easily achieved.
Furthermore, if the pipe is made of such a material, a predetermined mechanical strength can be obtained and the durability is excellent.
In addition, if piping is resin, although it is easy to process various shapes, even if it is other structural materials, for example, glass, ceramic, a metal, etc., it can use suitably depending on a use aspect.

Further, as shown in FIGS. 1A to 1B, flow rate adjusting members 14 and 28 for adjusting the amount of liquid developer in the pipe 12 are provided at the inlet and / or the outlet of the pipe 12. It is preferable that it is provided.
In this example, ball valves 14 and 28 as flow rate adjusting members are provided on the pipes before and after the measurement unit.
That is, as shown in FIG. 1A, when the liquid developer (F) flows into the pipe 12 via the ball valve 14 positioned in front of the measuring unit, the hole in the ball valve 14 The perforated wall 14a and the ball 14b are separated from each other, and the liquid developer (F) moves from left to right in the gap therebetween.
At that time, the movement of the ball 14b is restricted by the stopper 14c so that the perforated wall 14a and the ball 14b are not excessively separated.
On the other hand, in the ball valve 28 located behind the measuring unit, the perforated wall 28a and the ball 28b come into contact with each other, and the ball 28b closes the perforated wall 28a, so that no gap is generated therebetween. Therefore, the liquid developer (F) cannot move from the left to the right in the pipe located behind the measurement unit. At that time, since the perforated wall 28a and the ball 28b come into contact with each other, the ball 28b and the stopper 28c are separated from each other while maintaining a predetermined distance.

Further, as shown in FIG. 1B, when the liquid developer (F) flows out from the pipe 12, the ball valve 14 located in front of the measuring unit has a perforated wall 14a and a ball. 14b comes into contact and the ball 14b closes the perforated wall 14a, so that there is no gap between them. Therefore, the liquid developer (F) cannot move from the right to the left in the pipe located in front of the measurement unit. At this time, since the perforated wall 14a and the ball 14b come into contact with each other, the ball 14b and the stopper 14c are separated from each other while maintaining a predetermined distance.
On the other hand, in the ball valve 28 located behind the measuring unit, the perforated wall 28a and the ball 14b are separated from each other, and the liquid developer (F) moves from the left to the right through the gap therebetween. At this time, the movement of the ball 28b is restricted by the stopper 28c so that the perforated wall 28a and the ball 28b are not excessively separated.
In any case, since the ball valves 14 and 28 as flow rate adjusting members are provided in the pipes before and after the measurement unit, the detection accuracy of the light measurement device for a predetermined target substance is improved, and the predetermined liquid A part is extracted in a fluid state, and as a whole, the concentration of the target substance can be measured more accurately.

Moreover, the aspect of the ball valve 14 in the inlet_port | entrance of the piping 12 is demonstrated still in detail using FIG. 2 (a)-(c).
First, FIG. 2A is a view of the pipe 12 including the ball valve 14 as viewed from the left. A perforated wall 14a is visible inside the pipe 12, and a part of the ball 14b is further visible from the hole.
FIG. 2B is a cross-sectional view of the pipe 12 including the ball valve 14. In the pipe 12, a perforated wall 14a, a ball 14b, and a stopper 14c are sequentially provided.
Furthermore, FIG.2 (c) is the figure which looked at the piping 12 containing the ball valve 14 from the right-left direction. First, a rod-like stopper 14c that traverses the pipe 12 is seen inside the pipe 12, and a ball 14b is present at the tip of the stopper, and a part of the ball 14b is visible.
Therefore, by providing the ball valve 14 having such an aspect at the inlet of the pipe 12, a part of the predetermined liquid is extracted in a substantially fluid state, and the concentration of the target substance as a whole of the predetermined liquid is adjusted. Furthermore, it can be measured accurately.
Therefore, for example, the diameter of the hole in the perforated wall 14a is preferably set to a value within a range of 1/10 to 1/2 of the diameter of the pipe 12, and the diameter of the ball 14b is set to a value in the perforated wall 14a. While making it larger than the diameter of a hole, it is preferable to set it as the value within the range of 6 / 10-9 / 10 of the diameter of the piping 12. FIG.

2. Concentration Detection Unit As shown in FIGS. 1A to 1B, the concentration detection unit 19 is a part of the pipe 12 and is elastically deformed to a predetermined thickness by applying an external pressure (crank) 20. It is defined as a part to do.
That is, in the case of the toner concentration measuring apparatus 10 shown in FIGS. 1A to 1B, the transparent casing 18 and the pipe 12 through which the liquid developer passes are connected by the elastic member 16, and have a predetermined density. The detection unit is configured.
Therefore, when the transparent casing 18 moves up and down by an external pressure, the elastic member 16 made of NBR, fluororubber, or the like expands and contracts, and the liquid developer is moved between the measurement unit of the concentration detection unit and the pipe 12. The fluid flows in one direction while substantially maintaining the fluid state without leaking from the gap.
When the tip of the transparent casing 18 descends downward and comes into contact with the thickness adjusting member (spacer) 26, the toner concentration can be detected using the light measuring devices 22 and 24 described later. .

Here, as shown in FIGS. 1A to 1B, it is preferable that the concentration detector 19 is deformed to a predetermined thickness by pressurization of the crank 20 as an external pressure.
The reason for this is that by providing such a crank 20, it can function as a simple pump in cooperation with the transparent casing 18 and the elastic member 16. This is because it can be extracted while in a fluid state.
Therefore, the toner concentration in the liquid developer can be accurately measured as a whole by using the light measuring devices 22 and 24 described later in the density detector 19 while preventing the toner from settling.
The configuration of the crank 20 is not particularly limited. For example, as shown in FIG. 1, the disc body 20 a connected to a drive body (not shown) and the flat position thereof are attached. The driving shaft 20b and a pressing member 20c provided at the tip of the driving shaft 20b are preferably used.

Further, as shown in FIGS. 1A to 1B and FIGS. 5A to 5B, the thickness of the concentration detection unit is set to a predetermined value on the inside and / or the outside of the concentration detection unit 19. It is preferable to provide thickness adjusting members 26 and 102 for maintaining the value.
Here, FIGS. 1A to 1B are examples in which the spacer 26 is provided inside the concentration detector 19 as the thickness adjusting member 26.
As this spacer 26, the aspect shown to Fig.3 (a)-(d) is mentioned, for example. A side view of the spacer is shown on the left side of each drawing, and a plan view of the corresponding spacer is shown on the right side.

3A is an example of a spacer in which two linear members 26a made of a rectangular parallelepiped are provided in parallel on a rectangular flat plate 26b.
In such a form, not only the configuration is simple, but the flow of the liquid developer from the lateral direction is instantaneously interrupted, and the space between the two linear members 26a is used. The toner density can be accurately measured.

FIG. 3B shows an example of a spacer in which one linear member 26a made of a rectangular parallelepiped is provided on a rectangular flat plate 26b.
With such a configuration, not only the configuration is further simplified, but also any space formed on both sides of the linear member 26a by further instantaneously blocking the flow of the liquid developer from the lateral direction. Can be used to accurately measure the toner concentration.

FIG. 3C shows a spacer in which two linear members 26a made of a rectangular parallelepiped are provided on a rectangular flat plate 26b and two linear members 26a ′ are further provided in a direction perpendicular to the linear members 26a. It is an example.
In such a form, the flow of the liquid developer from the lateral direction is instantaneously interrupted, and the space formed inside the total of the four linear members 26a and 26a ′ is used. The toner density can be accurately measured.

FIG. 3D shows an example of a spacer in which a flat plate 26 a having a hollow 26 a ″ is provided on a rectangular flat plate 26 b.
With such a configuration, the flow of the liquid developer from the lateral direction can be instantaneously interrupted, and the toner concentration can be accurately measured using the hollow 26a ″.

On the other hand, FIGS. 5A to 5B are examples in which a rack and pinion 102 is provided outside the concentration detector 19 as a thickness adjusting member.
Examples of the basic operation in such a rack and pinion include the modes shown in FIGS.
That is, as shown in FIGS. 6A to 6B, a gear 102a ′ provided on the columnar support member 102a in the rack and pinion 102, and a gear 102b ′ provided on the horizontal portion 102b of the rack. However, the position of the horizontal portion 102b of the rack can be adjusted to a predetermined height by appropriately fitting.
Therefore, when the horizontal portion of the rack 102b and a part (projection) 18 ′ of the transparent casing 18 come into contact with each other, the vertical position of the density detection unit 19, that is, the thickness of the density detection unit 19 is set to a predetermined value. The thickness can be adjusted almost arbitrarily, whereby the function as the thickness adjusting member can be easily exhibited.

FIG. 6A shows a case where the meshing position in the rack and pinion 102 is a relatively lowered position, in which the flow of the liquid developer is partially inhibited, and the liquid development This corresponds to the case where the toner concentration in the agent is measured.
FIG. 6B shows the case where the meshing position in the rack and pinion 102 is relatively upward, and the liquid developer is in a completely fluid state and the toner concentration is not measured. Equivalent to.

In addition, it is preferable that the predetermined value of the thickness of the pipe is variable according to the type of toner in the liquid developer by the thickness adjusting member provided in the pipe.
For example, in the case of cyan toner having a toner density of 1 to 30% by weight with respect to the total amount, it is preferable to detect the density in a state where the thickness of the pipe is controlled to 1.5 mm, for example.
For cyan toner having a toner density of less than 1% by weight with respect to the total amount, for example, it is preferable to detect the density in a state where the thickness of the pipe is controlled to 5 mm.

Furthermore, when the toner concentration is 1 to 30% by weight with respect to the total amount, the thickness of the pipe is preferably 0.1 mm for black toner, and the thickness of the pipe is preferably 0.1 mm for yellow toner. The thickness is preferably 3 mm, for example, and in the case of magenta toner, the thickness of the pipe is preferably 1.5 mm, for example.
In addition, when the toner density is less than 1% by weight with respect to the total amount, the thickness of the pipe is preferably set to 5 mm for all color toners, for example.

3. Light Measuring Device As shown in FIGS. 1A to 1B, the light measuring devices 22 and 24 set the light transmittance (change in light amount) of the liquid developer (F) introduced into the pipe 12 to a predetermined thickness. It is defined as a part for measurement in the deformed density detector 19.
Here, as shown in FIGS. 1A to 1B, the light measuring devices 22 and 24 are configured by a light emitting unit 22 and a light receiving unit 24, and the light emitted from the light emitting unit 22. It is preferable to measure the toner concentration by measuring the change in the amount of light by the light receiving unit 24.
That is, when a space of a predetermined distance is filled with a liquid developer and light is transmitted therethrough, the amount of light that reaches the light receiving portion changes according to the toner concentration in the liquid developer. Therefore, after preparing several types of liquid developer having a predetermined toner concentration in advance, the amount of light received is measured, and then a calibration curve is created and compared with the calibration curve. The toner density can be calculated.

Moreover, as shown in FIG. 4, it is preferable that the light emission part 22 and the light-receiving part 24 in a light measuring device are the structures corresponding to the reflective measurement system provided in the same side with respect to the piping 12. As shown in FIG. That is, the light emitted from the light emitting unit 22 is once transmitted through the liquid developer as a measurement target, and then reflected by a reflecting member (not shown) provided in a part of the pipe 12, for example, an aluminum plate. is allowed to further transmit by diverting the liquid developer, it is preferable to measure the toner density from the reflected light of the condition.
The reason for this is that the optical path length is doubled by measuring in this way. Therefore, even if a part of the liquid developer is extracted in a fluid state, the overall density is determined based on a predetermined light measurement device. This is because can be measured more accurately.
In addition, by configuring the reflective measurement method in this way, the light emitting unit and the light receiving unit are provided on the same side with respect to the pipe, so that the size and the like of the light measuring device can be reduced. Because.
The arrangement relationship between the light emitting unit and the light receiving unit may correspond to the reflection type measurement method as described above, or as shown in FIGS. 1A to 1B, the transmission type measurement method. It may be a thing corresponding to.

[Second Embodiment]
The second embodiment relates to a wet developed image forming apparatus including the density measuring apparatus (toner density measuring apparatus) of the first embodiment.
That is, as shown in FIG. 7, an image forming apparatus (wet development image forming apparatus) 230 provided with a density measuring apparatus (toner density measuring apparatus) 10.

1. As shown in FIG. 7, the wet developing electrophotographic photosensitive member 231 to be mounted on the wet developing image forming apparatus 230 includes a single layer type and a laminated type, and any of them can be applied. is there.
However, it can be used for both positive and negative chargeability, has a simple structure and is easy to manufacture, can suppress film defects when forming a photoreceptor layer, has few interface between layers, and can improve optical characteristics. For these reasons, it is more preferable to apply to a single layer type.
It is also possible to use an amorphous silicon photoconductor excellent in durability.

2. Wet Image Forming Apparatus Further, as shown in FIG. 7, an electrophotographic photoreceptor for wet development (hereinafter sometimes simply referred to as a photoreceptor) 231 is provided, and a charging process is performed around the photoreceptor 231. A charger 232 for performing an exposure, an exposure light source 233 for performing an exposure process, a wet developing unit 234 for performing a development process, and a transfer unit 235 for performing a transfer process are arranged to form an image. This is a wet image forming apparatus 230.
In the following description of the wet image forming apparatus, a case where a single layer type photoreceptor is used as the electrophotographic photoreceptor for wet development will be described.

First, the photoreceptor 231 rotates at a constant speed in the direction of the arrow, and the electrophotographic process is performed on the surface of the photoreceptor 231 in the following order. More specifically, after the photosensitive member 231 is fully charged by the charger 232, the print pattern is exposed by the exposure light source 233. Next, the toner is developed by the wet developing device 234 corresponding to the print pattern, and the toner is transferred onto the transfer material (paper) 236 by the transfer device 235. Finally, excess toner remaining on the photoconductor 231 is scraped off by the cleaning blade 237 and the photoconductor 231 is neutralized by the neutralization light source 238.
Here, the liquid developer 234a in which the toner is dispersed is conveyed by the developing roller 234b, and the toner is attracted onto the surface of the photoconductor 231 by applying a predetermined developing bias, and developed on the photoconductor 231. Will be.

Then, as shown in FIG. 7, the solid content concentration in the liquid developer 234 a is, for example, within a range of 5 to 25 wt% by the density measuring device (toner density measuring device) 10 provided in the middle of the bypass 204. It is preferable to use a value.
In other words, the liquid developer 234a collected by the developing roller 234b after development is used by being connected to a developing device (developing tank) 234 for adjusting the density. Accordingly, the liquid developer 234a collected by the developing roller 234b is conveyed to the developing device 234, and a part of the liquid developer 234a is extracted, and the concentration is detected by the concentration measuring device (toner concentration measuring device) 10 in a substantially fluid state. Is done.
Therefore, when detecting the density, as shown in FIGS. 1A and 1B, the transparent casing 18 moves up and down, and the liquid developer 234a is transferred from the developing device 234 to the density measuring device (toner density measuring device) by the pump effect. Device) 10.
The density is detected using the light measuring devices 22 and 24 and then returned to the developing device 234 again. Then, while performing density detection, a liquid developer having a toner concentration higher than that of the liquid developer used in the carrier liquid or the developing device 234 is added to the developing device 234 until the target concentration is reached.
As the carrier liquid (toner dispersion solvent) used for the liquid developer 234a, a hydrocarbon solvent or a silicone oil is preferably used.

According to the density measuring apparatus (toner density measuring apparatus) of the present invention, the density measuring apparatus includes a predetermined pipe, a predetermined density detecting unit, and a predetermined light measuring device, thereby providing a liquid developer (wet type). The concentration of the liquid developer can be accurately measured while the developer is maintained in a substantially fluid state.
Therefore, the density measuring apparatus of the present invention is not only a toner density measuring apparatus in a wet image forming apparatus, but also various density measuring apparatuses, for example, a pigment concentration measuring apparatus in ink or a concentration detection of a specific substance dispersed in water. It can be used for such applications.
Further, the density measuring apparatus (toner density measuring apparatus) of the present invention itself can also function as a simple pump, so that a predetermined pump is not required even when mounted on an image forming apparatus or the like. As a whole, it is possible to obtain an effect that a small image forming apparatus or the like can be provided.

(A) And (b) is a figure provided in order to demonstrate basic operation | movement of the toner density | concentration measuring apparatus of this invention. (A)-(c) is a figure provided in order to demonstrate the valve structure of a toner concentration measuring apparatus. (A)-(d) is a figure provided in order to demonstrate the aspect of the thickness adjustment member used for this invention. It is a figure provided in order to explain the light measuring device of the toner concentration measuring device. (A) And (b) is a figure provided in order to demonstrate basic operation | movement of another toner density | concentration measuring apparatus of this invention. (A)-(b) is a figure provided in order to demonstrate the aspect of another thickness adjustment member used for this invention. It is a figure provided in order to demonstrate a wet image forming apparatus. It is a figure provided in order to demonstrate the conventional toner concentration measuring apparatus.

Explanation of symbols

10: Toner concentration measuring device 12: Pipe 14: Valve structure 14a: Perforated wall 14b: Ball 14c: Stopper 16: Elastic member 18: Transparent casing 18 ': Protrusion 19: Concentration detector 20: External pressure (crank)
20a: disk body 20b: drive shaft 20c: pressing member 22, 24: light measuring device 26: thickness adjusting member 26a: linear member 26b: flat plate 28: valve structure 28a: perforated wall 28b: ball 28c: stopper 100: Another toner concentration measuring device 102: another thickness adjusting member (rack and pinion)
102a: Support member 102a ': Gear 102b: Rack horizontal portion 102b': Gear 231: Photoconductor 232: Charger 233: Exposure light source 234: Wet developer 234a: Liquid developer (liquid developer)
234b: Development roller 235: Transfer device 236: Transfer material 237: Cleaning blade 238: Static electricity source 239: Probe F: Flow of liquid developer L: Direction of light travel

Claims (8)

A concentration measuring device for measuring the concentration of a target substance in a predetermined liquid,
Piping for feeding a predetermined liquid;
A part of the pipe is provided with a concentration detector that elastically deforms to a predetermined thickness by applying external pressure,
And a light measurement device for measuring the light transmittance of the predetermined liquid in a concentration detector in a state of being deformed to a predetermined thickness.   The concentration measuring apparatus according to claim 1, wherein the concentration detecting unit is deformed to a predetermined thickness by a crank as the external pressure.   The thickness adjusting member for maintaining the thickness of the density detection unit at a predetermined value is provided inside or outside the density detection unit, or any one of the density detection unit. Concentration measuring device.   The concentration measuring apparatus according to claim 3, wherein the thickness of the concentration detecting unit is made variable by the thickness adjusting member according to the type of the target substance in the predetermined liquid.   The flow rate adjusting member for adjusting the predetermined liquid amount in the said piping is provided in the inlet and / or the outlet of the said piping, or any one of Claims 1-4 characterized by the above-mentioned. Concentration measuring device.   The light measuring device includes a light emitting unit and a light receiving unit, and measures the light amount change of light emitted from the light emitting unit by measuring the concentration of the target substance by the light receiving unit. The density | concentration measuring apparatus as described in any one of Claims 1-5 characterized by these.   The density measuring apparatus according to claim 1, wherein the density measuring apparatus is a toner density measuring apparatus for measuring a toner density in the liquid developer. An image forming apparatus including a concentration measuring device for measuring the concentration of a target substance in a predetermined liquid,
The concentration measuring device is
Piping for feeding a predetermined liquid;
A part of the pipe is provided with a concentration detector that elastically deforms to a predetermined thickness by applying external pressure,
An image forming apparatus comprising: a light measuring device for measuring the light transmittance of the predetermined liquid in a concentration detection unit in a state of being deformed to a predetermined thickness.

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