JP2010091921A - Concentration detector, liquid developer concentration-adjusting device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concentration detector for exactly measuring concentration of a liquid being an object to be measured even if transmittance of the liquid is different, and to provide an image forming apparatus. <P>SOLUTION: The concentration detector includes: a light-emitting element 131a emitting light; light-emitting element holding parts 131b, 131c and 131d holding the light-emitting element 131a; a light-receiving element 132a receiving the light from the light-emitting element 131a; light-receiving element holding parts 132b, 132c and 132d holding the light-receiving element 132a; a rotating member 122 including a light transmission part 122a and a light-shielding part 122b and rotating so that the light transmission part may move through a gap 133 formed by the light-emitting element holding parts 131b, 131c and 131d and the light-receiving element holding parts 132b, 132c and 132d between the light-emitting element 131a and the light-receiving element 132a; and optical paths 131e and 132e constituted to receive the light from the light-emitting element 131a by the light-receiving element 132a without passing through the gap 133. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a concentration detection device, a liquid developer concentration adjustment device, and an image forming apparatus that detect the concentration of a liquid toner containing a carrier liquid and toner.

Conventionally, in order to accurately measure the toner concentration in an optically high-viscosity, high-concentration liquid developer, even when the light quantity of the light-emitting element changes due to temperature changes or temporal changes of the light-emitting element and the light-receiving element, light is used. A light emitting element that emits light, a branching unit that branches light from the light emitting element into two optical paths, and one of the two optical paths branched by the branching unit that receives light in one optical path that passes through the liquid developer. A first light receiving element that converts the first light signal into a first electric signal; a second light receiving element that receives light from the other optical path that does not pass through the liquid developer and converts the light into a second electric signal; There has been a toner concentration detection device having a comparison means for comparing with a second electric signal (see Patent Document 1).
JP 2000-330387A

However, since the technique described in Patent Document 1 requires a plurality of light receiving elements, the number of parts increases and the cost is high.

  In order to solve the above problems, the present invention provides a concentration detection device, a liquid developer concentration adjustment device, and an image forming device that accurately measure the concentration of a liquid with a simple structure even when the light amount of a light emitting element changes. The purpose is to provide.

  The concentration detection apparatus according to the present invention includes a light emitting element that emits light, a light emitting element holding unit that holds the light emitting element, a light receiving element that receives light from the light emitting element, and a light receiving element that holds the light receiving element. A holding portion, a light transmission portion, and a light shielding portion, wherein the light transmission portion moves between the light emitting element and the light receiving element in a gap formed by the light emitting element holding portion and the light receiving element holding portion; And a rotating member that rotates in such a manner, and an optical path portion configured such that light from the light emitting element is received by the light receiving element without passing through the gap.

  In addition, the concentration detection apparatus according to the present invention includes a light reducing member that is disposed in the light path portion and that reduces the amount of light received by the light receiving element.

  In the concentration detection apparatus according to the present invention, the rotating member has flexibility.

  In addition, the concentration detection apparatus according to the present invention includes a control unit that calculates the concentration by averaging the amount of light received by the light receiving element a plurality of times.

  Furthermore, the liquid developer concentration adjusting apparatus according to the present invention includes a developer storage section in which a liquid developer containing toner and a carrier liquid is stored, a light emitting element that emits light, and a light emitting element holding that holds the light emitting element. A light-receiving element that receives light from the light-emitting element, a light-receiving element holding part that holds the light-receiving element, a light-transmitting part, and a light-shielding part. A rotating member that rotates so as to move in a gap formed by the light emitting element holding part and the light receiving element holding part, and light from the light emitting element is received by the light receiving element without passing through the gap part. And a density detection unit disposed in the developer storage unit.

  Furthermore, an image forming apparatus according to the present invention includes a developer carrier that carries a liquid developer containing toner and a carrier liquid, and a developer carrier that collects the liquid developer carried on the developer carrier. A developing unit having a recovery member, an image carrier to be developed by the development unit, a developer storage unit for storing the liquid developer recovered by the developer carrier recovery member, and a developer storage unit A light emitting element for emitting light, a light emitting element holding part for holding the light emitting element, a light receiving element for receiving light from the light emitting element, a light receiving element holding part for holding the light receiving element, a light transmitting part and a light shielding part A rotating member that rotates so as to move the gap formed by the light emitting element holding part and the light receiving element holding part between the light emitting element and the light receiving element, and Light from the light emitting element passes through the gap. Wherein characterized in that it has a density detector having a light path portion configured to be received by the light receiving element, a liquid developer concentration adjusting section having a rather.

  The image forming apparatus according to the present invention further includes an interval adjusting unit that is disposed between the light emitting element holding unit and the light receiving element holding unit and adjusts the interval of the gap.

  The image forming apparatus according to the present invention also includes a second developer carrying member carrying a second liquid developer, and a second liquid developer collecting the second liquid developer carried on the second developer carrying member. (2) storing a second developing unit having a developer carrying member collecting member, a second image carrying member developed by the second developing unit, and a liquid developer collected by the second developer carrying member collecting member. A second developer storage section; a second light emitting element disposed in the second developer storage section for emitting light; a second light emitting element holding section for holding the second light emitting element; and the second light emitting element. A second light-receiving element that receives light from the light-receiving element, a second light-receiving element holding part that holds the second light-receiving element, a light-transmitting part, and a light-shielding part. The first gap portion formed by the second light emitting element holding portion and the second light receiving element holding portion between two light receiving elements A second rotating member that rotates so as to move in a second gap portion having a different interval, and light from the second light emitting element is received by the second light receiving element without passing through the second gap portion. And a second density detector having a second light path section, and a second liquid developer density adjusting section having a second density detector.

  According to the concentration detection apparatus of the present invention, the light intensity emitted from the light emitting element can be measured immediately before the concentration measurement with a simple structure, so that the accuracy of concentration detection can be improved.

  According to the concentration detection apparatus of the present invention, the distance between the light emitting element and the light receiving element can be adjusted in accordance with the transmittance of the liquid to be measured, so that the accuracy of concentration detection can be improved. It becomes.

  Further, according to the concentration detection apparatus of the present invention, it is possible to reduce the cost with a simple structure.

  In addition, according to the concentration detection apparatus of the present invention, the stagnation of the liquid between the light emitting element and the light receiving element is reduced, and the accuracy of concentration detection can be improved.

  Furthermore, according to the liquid developer concentration adjusting apparatus according to the present invention, the distance between the light emitting element and the light receiving element can be varied according to the color of the liquid developer having different transmittance, so that the density detection accuracy is improved. improves.

  Further, according to the image forming apparatus of the present invention, it is possible to form an image with good image quality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of the concentration detection apparatus according to the first embodiment. As shown in FIG. 1, the concentration detection device 120 includes a rotation shaft 121, a propeller 122 as an example of a rotation member, a concentration detection unit 130, and a detection unit mounting member 135.

  The propeller 122 has flexibility, is attached to the rotating shaft 121, and rotates together with the rotating shaft 121 by a motor or the like (not shown). The propeller 122 includes a transparent portion 122a as a light transmitting portion and a light shielding portion 122b. Further, the concentration detection unit 130 is attached to the detection unit attachment member 135, and the light emitting member 131, the light receiving member 132, the gap 133 as a gap portion disposed between the light emitting member 131 and the light receiving member 132, and light emission. It has a screw 134 as a connecting member for connecting the member 131 and the light receiving member 132.

  FIG. 2 is a front view of the concentration detection device in the storage member of the first embodiment. As shown in FIG. 2, the storage member 71 as a liquid storage unit includes a concentration detection device support member 71 a, rotatably supports the rotation shaft 121 of the concentration detection device 120, and the detection unit attachment member 135. To support.

  FIG. 3 is a diagram illustrating the propeller according to the first embodiment. As shown in FIG. 3, the propeller 122 is a long plate-like member, and has a transparent portion 122a as a light transmitting portion on one side with a hole 122c through which the rotating shaft 121 is inserted, and a light shielding portion on the other side. As a light shielding portion 122b. Moreover, it has the 1st edge part 122d and the 2nd edge part 122e shorter than the 1st edge part 122d.

  FIG. 4 is an enlarged front view of the vicinity of the concentration detector of the first embodiment. The propeller 122 is disposed so as to pass through the gap 133 as the rotating shaft 121 rotates. The screw 134 connects the flange portions of the light emitting member 131 and the light receiving member 132.

  FIG. 5 is an enlarged cross-sectional view of the vicinity of the concentration detection unit of the first embodiment, and FIG. 6 is a plan view of the vicinity of the concentration detection unit at the time of concentration detection of the first embodiment.

  The light emitting member 131 includes a light emitting element 131 a such as a light emitting LED, a light emitting element mounting plate 131 b to which the light emitting element 131 a is attached, a light emitting side transmitting member 131 c such as a glass plate disposed facing the gap 133, and light emission. The light emitting element holder 131d holding the element 131a, the light emitting element mounting plate 131b, and the light emitting side transmitting member 131c, and the light emitting side optical path 131e as an optical path portion formed in the light emitting element holder 131d. The light emitting element mounting plate 131b, the light emitting side transmission member 131c, and / or the light emitting element holder 131d constitute a light emitting element holding part.

  The light receiving member 132 includes a light receiving element 132a, a light receiving element mounting plate 132b to which the light receiving element 132a is attached, a light receiving side transmission member 132c such as a glass plate disposed facing the gap 133, and the light receiving element 132a and the light receiving element 132a. A light receiving element holder 132d that holds the element mounting plate 132b and the light receiving side transmitting member 132c, and a light receiving side optical path 132e as an optical path portion formed in the light receiving element holder 132d. The light receiving element mounting plate 132b, the light receiving side transmission member 132c, and / or the light receiving element holder 132d constitute a light receiving element holding portion.

  Between the light emitting member 131 and the light receiving member 132, a spacer 140 serving as a distance adjusting unit is disposed on the detection unit mounting member 135 side, and on the propeller 122 side, a gap is formed between the light emitting element holding unit and the light receiving element holding unit. 133 is formed.

  Next, the operation of the concentration detection device 120 of the first embodiment will be described.

  As shown in FIGS. 5 and 6, the propeller 122 is supported by the rotating shaft 121 and is formed of a rotatable rectangular plate or the like, and is a light emitting element 131 a disposed in the light emitting member 131 of the concentration detection unit 130. The transparent portion 122a is disposed in the gap 133 between the light receiving element 132a and the light receiving element 132a.

At the time of density detection, the propeller 122 is in a state where the transparent portion 122a is disposed in the optical path that is emitted from the light emitting element 131a and incident on the light receiving element 132a. Light emitted from the light emitting element 131a passes through the light emitting hole 131d ₁ provided on the light emitting element holder 131d, passes through the emission-side transmission member 131c, the liquid in the gap 133, the transparent portion 122a of the transparent propeller 122 and, again , through the liquid in the gap 133, transmitted through the reception side transmission member 132c, it passes through the light receiving hole 132d ₁ provided on the light receiving element holder 132d, enters the light receiving element 132a. Thus, by disposing the transparent portion 122a of the propeller 122 in the optical path that is emitted from the light emitting element 131a and incident on the light receiving element 132a, the thickness of the liquid on the optical path is reduced, and the transmittance is increased. It becomes possible to accurately detect the concentration of the liquid.

  FIG. 7 is an enlarged view of the vicinity of the concentration detector at the time of light intensity detection. FIG. 8 is a plan view of the vicinity of the concentration detector when detecting the light intensity. As shown in FIGS. 7 and 8, the propeller 122 is supported by the rotating shaft 121, is formed of a rotatable rectangular plate or the like, and is a light emitting element 131 a disposed in the light emitting member 131 of the concentration detection unit 130. The light shielding portion 122b is disposed in the gap 133 between the light receiving element 132a and the light receiving element 132a.

FIG. 9 is a perspective view of the vicinity of the propeller excluding some members. As shown in FIG. 9, the light emitting side transmitting member 131c, the light receiving side transmitting member 132c, and the spacer 140 have a first hole 131c ₁ , a second hole 132c _2, and a third hole 140 ₁ , respectively, and the light emitting side optical path 131e. reflection plate 141 as dimming member in the third hole 140 ₁ to face to the light receiving side light path 132e is provided with a light passing through the.

  At the time of detecting the light intensity, since the light shielding portion 122b of the propeller 122 is disposed in the gap 133, the light receiving element 132a emits from the light emitting element 131a, and the light emitting side optical path 131e, the reflecting plate 141, and the light receiving side optical path. Only light having passed through 132e is received. By detecting in this way, it is possible to detect the intensity of light emitted from the light emitting element 131a.

  FIG. 10 is a view showing a state in which the propeller 122 rotates and the propeller 122 comes out of the gap. As shown in FIG. 10, the propeller 122 can rotate around the rotation shaft 121. The propeller 122 rotates around the rotating shaft 121 to scrape out the liquid in the gap 133 and the new liquid flows into the gap 133, so that the liquid is reduced from stagnation in the gap 133. The accuracy can be improved.

  FIG. 11 is a system diagram of the concentration measuring unit 130. The light emitting element 131a and the light receiving element 132a are connected to a CPU 137 as a control unit via an amplifier 136, respectively.

  Next, a detection method of the concentration measuring apparatus 120 having such a configuration will be described. FIG. 12 is a diagram illustrating a detection flowchart of the concentration measuring apparatus 120.

  First, in step 1, the light emitting element 131a is turned on to emit light (ST1).

  Subsequently, in step 2, the light receiving intensity of the light receiving element 132a when the light shielding portion 122b of the propeller 122 is in the gap 133 is measured (ST2).

  Next, in step 3, a correction value α is calculated (ST3). The correction value α is obtained by comparing the reference value of the light emitting element 131a stored in advance with the measured value measured by the light receiving element 132a in step 2.

  Next, in step 4, the light receiving intensity of the light receiving element 132a when the transparent portion 122a of the propeller 122 is in the gap 133 is measured (ST4).

  Subsequently, in step 5, density correction is executed by the CPU 134 to obtain the density of the liquid developer (ST5). The concentration of the liquid developer is obtained from the product of the value measured in step 4 and the correction value α obtained in step 3.

  With such a concentration detection method, the concentration of the liquid in the storage member 71 can be detected.

  13 and 14 are enlarged views of the vicinity of the density detection unit. The spacer 140 disposed in the concentration detection unit 130 can be replaced. Therefore, by replacing the spacer 140 in accordance with the transmittance of the liquid to be detected, it is possible to adjust the thickness of the liquid on the optical path and detect it with high accuracy.

  For example, the spacer 140a shown in FIG. 13 is thinner than the spacer 140b shown in FIG. Even when the liquid transmittance is low, by applying the thin spacer 140a shown in FIG. 13, the thickness of the liquid on the optical path can be reduced and detection can be performed with high accuracy.

  FIG. 15 is a diagram illustrating another embodiment of the interval adjusting unit. In the concentration detection unit of another embodiment, a spring 138 as an elastic member is disposed between the light emitting member 131 and the light receiving member 132, and the interval between the light emitting member 131 and the light receiving member 132 is adjusted by a screw 134 as a connecting member. It has a configuration. In this case, the spring 138 and the screw 134 constitute an interval adjusting unit.

  Therefore, by rotating the screw 134 in accordance with the transmittance of the liquid to be detected, it is possible to continuously adjust the thickness of the liquid on the optical path and detect it with higher accuracy. For example, even when the liquid transmittance is low, by rotating the screw 134, the thickness of the liquid on the optical path can be reduced and detection can be performed with high accuracy.

  Next, the configuration of the concentration detection apparatus 120 of the second embodiment will be described. FIG. 16 is an enlarged view of the vicinity of the concentration detection unit at the time of light intensity detection according to the second embodiment.

  The density detection device 120 of the second embodiment has a structure in which a first reflecting plate 141a and a second reflecting plate 141b as light reducing members are provided instead of the reflecting plate 141 of the first embodiment.

  As shown in FIG. 16, in the second embodiment, a light emitting side optical path 131e is provided in the light emitting element holder 131d, a first reflector 141a is provided in the light emitting side optical path 131e, and the light receiving element holder 132d is provided in the light receiving element holder 132d. The light receiving side optical path 132e is provided, and the second reflecting plate 142a is disposed in the light receiving side optical path 132e.

  As shown in FIGS. 16 and 17, the propeller 122 is supported by the rotating shaft 121 and is formed of a rotatable flat plate member such as a rectangle, and the light emitting element 131 a disposed in the light emitting member 131 of the concentration detection unit 130. The light shielding portion 122b is disposed in the gap 133 between the light receiving element 132a and the light receiving element 132a.

FIG. 17 is a perspective view of the vicinity of the propeller excluding some members. As shown in FIG. 17, the light emitting side transmitting member 131c, the light receiving side transmitting member 132c, and the spacer 140 have a first hole 131c ₁ , a second hole 132c _2, and a third hole 140 ₁ , respectively, and emit light from the light emitting element 131a. The light that has passed through the light emitting side optical path 131e and the first reflecting plate 141a is the first hole 131c ₁ of the light emitting side transmitting member 131c, the third hole 140 ₁ of the spacer 140, and the second of the light receiving side transmitting member 132c. The light passes through the hole 132c ₂ and enters the light receiving element 132a through the light receiving side optical path 132e and the second reflecting plate 141b.

  At the time of detecting the light intensity, since the light shielding portion 122b of the propeller 122 is disposed in the gap 133, the light receiving element 132a emits from the light emitting element 131a, and the light emitting side optical path 131e, the reflecting plate 141, and the light receiving side optical path. Only light having passed through 132e is received. By detecting in this way, it is possible to detect the intensity of light emitted from the light emitting element 131a.

  Next, the configuration of the concentration detection apparatus 120 according to another embodiment will be described. FIG. 18 is an enlarged view of the vicinity of the density detector at the time of light intensity detection according to the third embodiment, and FIG. 19 is an enlarged view of the vicinity of the density detector at the time of light intensity detection of the fourth embodiment.

Concentration detection device 120 of the third embodiment, the light-receiving element receiving portion 132d ₁ of the light receiving element holder 132d of the first embodiment, it is subjected to absorption treatment which prevents irregular reflection as a dimming member. The light absorption treatment is a treatment such as coating a light-absorbing coating material, roughening the surface, or painting black.

  The concentration detection device 120 of the fourth embodiment has a structure in which a neutral density filter 142 as a neutral density member is disposed in the vicinity of the entrance of the light emission side optical path 131e of the light emitting element holder 131d of the first embodiment. The neutral density filter 142 is not limited to the position shown in FIG. 19 and may be anywhere on the optical path connecting the light emitting element 131a and the light receiving element 132a when detecting the light intensity.

  Moreover, it is good also as a structure of reducing the reflectance of the reflective mirror 141, etc.

  With this configuration, it is possible to reduce irregular reflection of light from the light emitting element 131a, make the amount of light received by the light receiving element 132a comparable to that during density detection, and improve accuracy.

  Next, a description will be given of a case where such a density detection device 120 is applied to an image forming apparatus as a liquid developer concentration adjustment device.

  FIG. 20 is a diagram showing main components constituting the image forming apparatus according to the embodiment of the present invention. In the present embodiment, each color liquid developer is composed of black K as the first color, cyan C as the second color, yellow Y as the third color, and magenta M as the fourth color. The member using black K is the first member, the member using cyan C is the second member, the member using yellow Y is the third member, and the member using magenta M is Corresponds to the fourth member.

  The image forming unit includes image carriers 10Y, 10M, 10C, and 10K, corona chargers 11Y, 11M, 11C, and 11K, exposure units 12Y, 12M, 12C, and 12K. The exposure units 12Y, 12M, 12C, and 12K include line heads and the like in which LEDs are arranged, and the image carriers 10Y, 10M, 10C, and 10K are uniformly charged by the corona chargers 11Y, 11M, 11C, and 11K. The exposure units 12Y, 12M, 12C, and 12K perform lighting control based on the input image signals, and form electrostatic latent images on the charged image carriers 10Y, 10M, 10C, and 10K.

  The developing devices 30Y, 30M, 30C, and 30K generally include liquid developers of respective colors including the developing rollers 20Y, 20M, 20C, and 20K, yellow (Y), magenta (M), cyan (C), and black (K). Developer containers 31Y, 31M, 31C, 31K to be stored, and developer supply rollers 32Y, 32M that supply liquid developers of these colors from the developer containers 31Y, 31M, 31C, 31K to the developing rollers 20Y, 20M, 20C, 20K. , 32C, 32K, developing rollers 20Y, 20M, 20C, and 20K, and developing roller cleaning blades 21Y, 21M, 21C, and 21K as liquid developer carrying member cleaning members for cleaning the liquid developer carried on the rollers. An electrostatic latent image formed on the image carrier 10Y, 10M, 10C, or 10K by a liquid developer The image. At least the developing rollers 20Y, 20M, 20C, and 20K and the developing roller cleaning blades 21Y, 21M, 21C, and 21K constitute a developing unit.

  The intermediate transfer member 40 is an endless belt member and is wound around and stretched between a driving roller 41 and a tension roller 42. The image transfer members 10Y, 10M, 10C are primary transfer units 50Y, 50M, 50C, 50K. 10K and is driven to rotate by the drive roller 41 while abutting 10K. The primary transfer portions 50Y, 50M, 50C, and 50K are arranged such that the primary transfer rollers 51Y, 51M, 51C, and 51K are opposed to each other with the image transfer bodies 10Y, 10M, 10C, and 10K sandwiched between the intermediate transfer body 40 and the image transfer bodies 10Y, Using the contact position with 10M, 10C, and 10K as the transfer position, the developed toner images of the respective colors on the image carriers 10Y, 10M, 10C, and 10K are sequentially superimposed and transferred onto the intermediate transfer body 40 to obtain a full-color toner. Form an image.

  In the secondary transfer unit 60, a secondary transfer roller 61 is disposed opposite to the belt drive roller 41 with the intermediate transfer member 40 interposed therebetween, and a cleaning device including a secondary transfer roller cleaning blade 62 and a developer recovery unit 63 is disposed. The In the secondary transfer unit 60, the sheet material conveyance path L is synchronized with the timing at which a full-color toner image or a single-color toner image formed on the intermediate transfer body 40 reaches the transfer position of the secondary transfer unit 60. Then, a sheet material such as paper, film or cloth is conveyed and supplied, and a single-color toner image or a full-color toner image is secondarily transferred to the sheet material.

  Further, a fixing unit (not shown) is disposed downstream of the sheet material conveyance path L, and a single-color toner image or a full-color toner image transferred onto a recording medium such as paper is fused and fixed to the recording medium. The image formation on the final sheet material is finished.

  On the side of the tension roller 42 that stretches the intermediate transfer body 40 together with the belt driving roller 41, a cleaning device including an intermediate transfer body cleaning blade 46 and a developer recovery unit 47 is disposed along the outer periphery thereof. The intermediate transfer body 40 after passing through the unit 60 proceeds to the winding portion of the tension roller 42, the intermediate transfer body 40 is cleaned by the intermediate transfer body cleaning blade 46, and again goes to the primary transfer section 50. .

  Developer collecting and replenishing devices 70Y, 70M, 70C, and 70K adjust the concentration of the liquid developer collected from the image carriers 10Y, 10M, 10C, and 10K and the developing devices 30Y, 30M, 30C, and 30K, and a developer container 31Y. , 31M, 31C, 31K.

  Next, the developer collection and supply devices 70Y, 70M, 70C, and 70K will be described. FIG. 14 is a cross-sectional view showing the main components of the developer collection and supply devices 70Y, 70M, 70C, and 70K. Since the configurations of the developer collection and supply devices 70Y, 70M, 70C, and 70K for the respective colors are the same, the following description is based on the yellow (Y) developer collection and supply device 70Y.

  As shown in FIG. 21, the developer collecting and replenishing device 70Y stores the collected liquid developer, replenishes the high concentration developer from the developer tank 74Y, and replenishes the carrier liquid from the carrier liquid tank 77Y, and adjusts the density. A liquid developer storing member 71Y.

  In the present embodiment, the liquid developer is recovered from the developing device 30Y and the image carrier 10Y. The liquid developer recovered in the recovery side storage container 31aY of the developing device 30Y and moved by the developer recovery screw 34Y is recovered in the liquid developer storage member 71Y via the developing device recovery path 72Y. Further, the liquid developer recovered from the image carrier 10Y by the cleaning device including the image carrier cleaning blade 17Y and the developer recovery unit 18Y is recovered to the liquid developer storage member 71Y via the image carrier recovery path 73Y. Is done.

  Further, the high-density developer is supplied from the developer tank 74Y to the liquid developer storage member 71Y via the developer supply path 75 and the developer pump 76. Further, the carrier liquid is supplied from the carrier liquid tank 77Y to the liquid developer storage member 71Y via the carrier liquid supply path 78Y and the carrier liquid pump 79Y. In addition, it is good also as a structure which replenishes by opening and closing of a valve | bulb etc. using gravity instead of a pump.

  The liquid developer stored in the liquid developer storage member 71Y is supplied to the supply side storage container 31bY of the developer container 31Y via the developer supply path 81Y and the developer supply pump 82Y.

  The concentration detection device 120Y includes a rotating shaft 121Y, a propeller 122Y as an example of a rotating member, an agitation propeller 123Y as an example of an agitation member, and a concentration detection unit 130Y. The stirring propeller shaft 121Y is a member that is provided with a propeller 122Y and a stirring propeller 123Y coaxially and is rotated by a motor 124Y.

  Since the concentration detection unit 130Y may be the same as the structure shown in FIGS. 1 to 19, the description of the same contents is omitted.

  FIG. 22 is a graph showing, for each color, the output voltage of the density detector 120 with respect to the density of the liquid developer when the gap 133 is the same. As can be seen from the graph, black K as the first color, cyan C as the second color, yellow Y as the third color, and magenta M as the fourth color have the same density. On the other hand, the output voltage is greatly different. Further, the output voltages of cyan C as the second color, yellow Y as the third color, and magenta M as the fourth color are also different for the same density. Thus, when the distance of the gap 133 is the same, the transmittance of each color is different, and the output voltage varies.

  FIG. 23 is a diagram showing a density detection device 120 applied to the image forming apparatus of the present embodiment. In this embodiment, as shown in FIG. 23, the distance of the gap 133 as the gap portion is made different depending on the color of the liquid developer.

  For example, the distance of the black K gap 133K and the distances of the other cyan C, yellow Y, and magenta M gaps 133C, 133Y, and 133M are made different. It is preferable that the distance of the gap K of black K having a low transmittance is shorter than the distances of the gaps 133C, 133Y, and 133M of other cyan C, yellow Y, and magenta M.

  Alternatively, the distances of the black K gap 133K, the cyan C gap 133C, and the yellow Y and magenta M gap 133 may be different. The distance of the black K gap 133K having the low transmittance is made shorter than the distance of the cyan C gap 133C, and the distance of the cyan C gap 133C having the next low transmittance is set to be the distance of the yellow Y and magenta M gaps 133Y and 133M. It is preferable to shorten it.

  Furthermore, the distances of the gaps 133 for all colors may be varied. The distance of the black K gap 133K having a low transmittance is made shorter than the distance of the cyan C gap 133C, and then the distance of the cyan C gap 133C having the low transmittance is made shorter than the distance of the magenta M gap 133M. It is preferable that the distance of the gap 133M of magenta M having a low transmittance is shorter than the distance of the gap 133M of yellow Y.

  According to the concentration detection device 120 of the present embodiment, the light intensity emitted from the light emitting element 131a can be measured immediately before the concentration measurement with a simple structure, so that the accuracy of concentration detection can be improved. Become.

  Further, according to the concentration detection device 120 of the present embodiment, the interval between the light emitting element 131a and the light receiving element 132a can be adjusted according to the transmittance of the liquid to be measured, so that the accuracy of concentration detection is increased. It becomes possible to improve.

  Further, according to the concentration detection apparatus 120 of the present embodiment, it is possible to reduce the cost with a simple structure.

  In addition, according to the concentration detection device 120 of the present embodiment, the stagnation of the liquid in the gap 133 between the light emitting element 131a and the light receiving element 132a is reduced, and the accuracy of concentration detection can be improved.

  Furthermore, according to the liquid developer concentration adjusting apparatus of the present embodiment, the distance between the light emitting element 131a and the light receiving element 132a can be made different according to the color of the liquid developer having different transmittance. Accuracy is improved.

  Further, according to the image forming apparatus of the present invention, it is possible to form an image with good image quality.

It is a perspective view of the density | concentration detection apparatus of 1st Embodiment. It is a front view of the density | concentration detection apparatus in a storage member. It is a figure which shows the propeller of 1st Embodiment. It is an enlarged view near a density detection unit. It is sectional drawing to which the density | concentration detection part vicinity at the time of density | concentration detection was expanded. It is the top view to which the density detection part vicinity at the time of density detection was expanded. It is sectional drawing to which the density detection part vicinity at the time of light intensity detection was expanded. It is the top view which expanded the density detection part vicinity at the time of light intensity detection. It is a perspective view near the propeller excluding some members. It is a figure which shows the state which the propeller rotated. It is a system diagram of a density | concentration measurement part. It is a figure which shows the flowchart at the time of the detection of a density | concentration detection apparatus. It is an enlarged view near a density detection unit. It is an enlarged view near a density detection unit. It is a figure which shows other embodiment of a space | interval adjustment member. It is an enlarged view of the vicinity of the concentration detection unit at the time of light intensity detection of the second embodiment. It is a perspective view near the propeller excluding some members. It is an enlarged view of the vicinity of the concentration detection unit at the time of light intensity detection of the third embodiment. It is an enlarged view of the vicinity of the concentration detection unit at the time of light intensity detection of the third embodiment. 1 is a diagram illustrating an embodiment of an image forming apparatus. FIG. 3 is a cross-sectional view illustrating main components of an image forming unit and a developing device. It is the graph which represented the output voltage of the density | concentration detection apparatus with respect to the density | concentration of the liquid developer when the clearance gap is made the same for every color. It is a figure which shows the density | concentration detection apparatus applied to the image forming apparatus of this embodiment.

Explanation of symbols

  10Y, 10M, 10C, 10K ... image carrier, 11Y, 11M, 11C, 11K ... corona charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y ... image carrier squeeze roller, 14Y ... cleaning blade, 16Y ... Static elimination device, 17Y ... photosensitive blade, 18Y ... photosensitive member cleaning liquid recovery unit, 20Y, 20M, 20C, 20K ... developing roller (developer carrier), 21Y ... developing roller blade, 30Y, 30M, 30C, 30K ... developing Device, 31Y, 31M, 31C, 31K ... Developer container, 31aY ... Recovery unit, 31bY ... Supply unit, 32Y, 32M, 32C, 32K ... Developer supply roller (developer supply member), 33Y ... Developer regulating blade ( Developer regulating member), 34Y ... recovery screw, 35Y ... communication portion, 36Y ... stirring paddle (stirring) 50Y, 50M, 50C, 50K ... primary transfer backup roller, 40 ... intermediate transfer member, 41 ... belt drive roller, 42 ... tension roller, 46 ... intermediate transfer belt cleaning blade, 47 ... intermediate transfer belt cleaning liquid recovery unit , 50 ... primary transfer unit, 51 ... primary transfer roller, 60 ... secondary transfer unit, 61 ... secondary transfer roller, 62 ... secondary transfer roller blade, 63 ... secondary transfer roller cleaning liquid recovery unit, 70Y ... developer Collecting and replenishing device, 71Y ... storage member, 72Y ... developing device collecting path, 73Y ... image carrier collecting path, 74Y ... developer tank, 75Y ... developer replenishing path, 76Y ... developer pump, 77Y ... carrier liquid tank, 78Y ... Carrier liquid supply path, 79Y ... Carrier liquid pump, 81Y ... Developer supply path, 82Y ... Developer supply pump, DESCRIPTION OF SYMBOLS 120 ... Concentration detection apparatus, 121 ... Rotating shaft (stirring propeller shaft), 122 ... Propeller (rotating member), 123Y ... Stirring propeller (stirring member), 124Y ... Motor, 130 ... Concentration detecting part, 131 ... Light emitting member, 131a ... Light emitting element, 132 ... light receiving member, 132a ... light receiving element, 133 ... gap (gap part), 140 ... spacer (gap adjusting part), 141 ... reflecting plate

Claims (8)

A light emitting element that emits light;
A light emitting element holding unit for holding the light emitting element;
A light receiving element that receives light from the light emitting element;
A light receiving element holding portion for holding the light receiving element;
A light transmitting portion and a light shielding portion, wherein the light transmitting portion rotates between the light emitting element and the light receiving element so as to move a gap formed by the light emitting element holding portion and the light receiving element holding portion; A rotating member that
An optical path configured to receive light from the light emitting element to the light receiving element without passing through the gap;
A concentration detection apparatus comprising: The density detection apparatus according to claim 1, further comprising a light reducing member that is disposed in the light path portion and reduces a light amount of light received by the light receiving element. The concentration detecting apparatus according to claim 2, wherein the rotating member has flexibility. The density detection apparatus according to claim 1, further comprising a control unit that calculates a density by averaging the amount of light received by the light receiving element a plurality of times. A developer reservoir for storing a liquid developer containing toner and carrier liquid;
A light emitting element that emits light, a light emitting element holding unit that holds the light emitting element, a light receiving element that receives light from the light emitting element, a light receiving element holding unit that holds the light receiving element, a light transmitting unit, and a light shielding unit. A rotating member that rotates so that the light transmission portion moves between the light emitting element and the light receiving element in a gap formed by the light emitting element holding part and the light receiving element holding part; and A light path portion configured to be received by the light receiving element without passing through the gap portion, and a concentration detection portion disposed in the developer storage portion,
A liquid developer concentration adjusting apparatus comprising: A developer carrying member that carries a liquid developer containing toner and carrier liquid, and a developer carrying member collecting member that collects the liquid developer carried on the developer carrier;
An image carrier to be developed in the developing unit;
A developer reservoir that stores the liquid developer collected by the developer carrier recovery member, a light emitting element that is disposed in the developer reservoir and emits light, and a light emitting element that holds the light emitting element A light-receiving element that receives light from the light-emitting element, a light-receiving element holding part that holds the light-receiving element, a light-transmitting part, and a light-shielding part. A rotating member that rotates so as to move in a gap formed by the light emitting element holding part and the light receiving element holding part, and light from the light emitting element is received by the light receiving element without passing through the gap part. A concentration detector having a light path portion configured to have a liquid developer concentration adjusting unit,
An image forming apparatus comprising:   The image forming apparatus according to claim 6, further comprising an interval adjusting unit that is disposed between the light emitting element holding unit and the light receiving element holding unit and adjusts the interval of the gap. A second developer carrying member for carrying a second liquid developer; and a second developer carrying member collecting member for collecting the second liquid developer carried on the second developer carrying member. A developing section;
A second image carrier to be developed in the second developing unit;
A second developer reservoir that stores the liquid developer recovered by the second developer carrier recovery member; a second light emitting element that is disposed in the second developer reservoir and emits light; A second light-emitting element holding unit for holding the second light-emitting element; a second light-receiving element for receiving light from the second light-emitting element; a second light-receiving element holding unit for holding the second light-receiving element; And the light transmission part is formed between the second light emitting element and the second light receiving element by the second light emitting element holding part and the second light receiving element holding part. And a second rotating member that rotates so as to move in a second gap having a different interval from each other, and light from the second light emitting element is received by the second light receiving element without passing through the second gap. A second concentration detector having a second light path portion, a second liquid developer concentration adjusting unit,
The image forming apparatus according to claim 6 or 7, comprising:

Images